1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Performance events core code: 4 * 5 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de> 6 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar 7 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra 8 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com> 9 */ 10 11 #include <linux/fs.h> 12 #include <linux/mm.h> 13 #include <linux/cpu.h> 14 #include <linux/smp.h> 15 #include <linux/idr.h> 16 #include <linux/file.h> 17 #include <linux/poll.h> 18 #include <linux/slab.h> 19 #include <linux/hash.h> 20 #include <linux/tick.h> 21 #include <linux/sysfs.h> 22 #include <linux/dcache.h> 23 #include <linux/percpu.h> 24 #include <linux/ptrace.h> 25 #include <linux/reboot.h> 26 #include <linux/vmstat.h> 27 #include <linux/device.h> 28 #include <linux/export.h> 29 #include <linux/vmalloc.h> 30 #include <linux/hardirq.h> 31 #include <linux/hugetlb.h> 32 #include <linux/rculist.h> 33 #include <linux/uaccess.h> 34 #include <linux/syscalls.h> 35 #include <linux/anon_inodes.h> 36 #include <linux/kernel_stat.h> 37 #include <linux/cgroup.h> 38 #include <linux/perf_event.h> 39 #include <linux/trace_events.h> 40 #include <linux/hw_breakpoint.h> 41 #include <linux/mm_types.h> 42 #include <linux/module.h> 43 #include <linux/mman.h> 44 #include <linux/compat.h> 45 #include <linux/bpf.h> 46 #include <linux/filter.h> 47 #include <linux/namei.h> 48 #include <linux/parser.h> 49 #include <linux/sched/clock.h> 50 #include <linux/sched/mm.h> 51 #include <linux/proc_ns.h> 52 #include <linux/mount.h> 53 #include <linux/min_heap.h> 54 #include <linux/highmem.h> 55 #include <linux/pgtable.h> 56 #include <linux/buildid.h> 57 #include <linux/task_work.h> 58 59 #include "internal.h" 60 61 #include <asm/irq_regs.h> 62 63 typedef int (*remote_function_f)(void *); 64 65 struct remote_function_call { 66 struct task_struct *p; 67 remote_function_f func; 68 void *info; 69 int ret; 70 }; 71 72 static void remote_function(void *data) 73 { 74 struct remote_function_call *tfc = data; 75 struct task_struct *p = tfc->p; 76 77 if (p) { 78 /* -EAGAIN */ 79 if (task_cpu(p) != smp_processor_id()) 80 return; 81 82 /* 83 * Now that we're on right CPU with IRQs disabled, we can test 84 * if we hit the right task without races. 85 */ 86 87 tfc->ret = -ESRCH; /* No such (running) process */ 88 if (p != current) 89 return; 90 } 91 92 tfc->ret = tfc->func(tfc->info); 93 } 94 95 /** 96 * task_function_call - call a function on the cpu on which a task runs 97 * @p: the task to evaluate 98 * @func: the function to be called 99 * @info: the function call argument 100 * 101 * Calls the function @func when the task is currently running. This might 102 * be on the current CPU, which just calls the function directly. This will 103 * retry due to any failures in smp_call_function_single(), such as if the 104 * task_cpu() goes offline concurrently. 105 * 106 * returns @func return value or -ESRCH or -ENXIO when the process isn't running 107 */ 108 static int 109 task_function_call(struct task_struct *p, remote_function_f func, void *info) 110 { 111 struct remote_function_call data = { 112 .p = p, 113 .func = func, 114 .info = info, 115 .ret = -EAGAIN, 116 }; 117 int ret; 118 119 for (;;) { 120 ret = smp_call_function_single(task_cpu(p), remote_function, 121 &data, 1); 122 if (!ret) 123 ret = data.ret; 124 125 if (ret != -EAGAIN) 126 break; 127 128 cond_resched(); 129 } 130 131 return ret; 132 } 133 134 /** 135 * cpu_function_call - call a function on the cpu 136 * @cpu: target cpu to queue this function 137 * @func: the function to be called 138 * @info: the function call argument 139 * 140 * Calls the function @func on the remote cpu. 141 * 142 * returns: @func return value or -ENXIO when the cpu is offline 143 */ 144 static int cpu_function_call(int cpu, remote_function_f func, void *info) 145 { 146 struct remote_function_call data = { 147 .p = NULL, 148 .func = func, 149 .info = info, 150 .ret = -ENXIO, /* No such CPU */ 151 }; 152 153 smp_call_function_single(cpu, remote_function, &data, 1); 154 155 return data.ret; 156 } 157 158 static void perf_ctx_lock(struct perf_cpu_context *cpuctx, 159 struct perf_event_context *ctx) 160 { 161 raw_spin_lock(&cpuctx->ctx.lock); 162 if (ctx) 163 raw_spin_lock(&ctx->lock); 164 } 165 166 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx, 167 struct perf_event_context *ctx) 168 { 169 if (ctx) 170 raw_spin_unlock(&ctx->lock); 171 raw_spin_unlock(&cpuctx->ctx.lock); 172 } 173 174 #define TASK_TOMBSTONE ((void *)-1L) 175 176 static bool is_kernel_event(struct perf_event *event) 177 { 178 return READ_ONCE(event->owner) == TASK_TOMBSTONE; 179 } 180 181 static DEFINE_PER_CPU(struct perf_cpu_context, perf_cpu_context); 182 183 struct perf_event_context *perf_cpu_task_ctx(void) 184 { 185 lockdep_assert_irqs_disabled(); 186 return this_cpu_ptr(&perf_cpu_context)->task_ctx; 187 } 188 189 /* 190 * On task ctx scheduling... 191 * 192 * When !ctx->nr_events a task context will not be scheduled. This means 193 * we can disable the scheduler hooks (for performance) without leaving 194 * pending task ctx state. 195 * 196 * This however results in two special cases: 197 * 198 * - removing the last event from a task ctx; this is relatively straight 199 * forward and is done in __perf_remove_from_context. 200 * 201 * - adding the first event to a task ctx; this is tricky because we cannot 202 * rely on ctx->is_active and therefore cannot use event_function_call(). 203 * See perf_install_in_context(). 204 * 205 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set. 206 */ 207 208 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *, 209 struct perf_event_context *, void *); 210 211 struct event_function_struct { 212 struct perf_event *event; 213 event_f func; 214 void *data; 215 }; 216 217 static int event_function(void *info) 218 { 219 struct event_function_struct *efs = info; 220 struct perf_event *event = efs->event; 221 struct perf_event_context *ctx = event->ctx; 222 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); 223 struct perf_event_context *task_ctx = cpuctx->task_ctx; 224 int ret = 0; 225 226 lockdep_assert_irqs_disabled(); 227 228 perf_ctx_lock(cpuctx, task_ctx); 229 /* 230 * Since we do the IPI call without holding ctx->lock things can have 231 * changed, double check we hit the task we set out to hit. 232 */ 233 if (ctx->task) { 234 if (ctx->task != current) { 235 ret = -ESRCH; 236 goto unlock; 237 } 238 239 /* 240 * We only use event_function_call() on established contexts, 241 * and event_function() is only ever called when active (or 242 * rather, we'll have bailed in task_function_call() or the 243 * above ctx->task != current test), therefore we must have 244 * ctx->is_active here. 245 */ 246 WARN_ON_ONCE(!ctx->is_active); 247 /* 248 * And since we have ctx->is_active, cpuctx->task_ctx must 249 * match. 250 */ 251 WARN_ON_ONCE(task_ctx != ctx); 252 } else { 253 WARN_ON_ONCE(&cpuctx->ctx != ctx); 254 } 255 256 efs->func(event, cpuctx, ctx, efs->data); 257 unlock: 258 perf_ctx_unlock(cpuctx, task_ctx); 259 260 return ret; 261 } 262 263 static void event_function_call(struct perf_event *event, event_f func, void *data) 264 { 265 struct perf_event_context *ctx = event->ctx; 266 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */ 267 struct event_function_struct efs = { 268 .event = event, 269 .func = func, 270 .data = data, 271 }; 272 273 if (!event->parent) { 274 /* 275 * If this is a !child event, we must hold ctx::mutex to 276 * stabilize the event->ctx relation. See 277 * perf_event_ctx_lock(). 278 */ 279 lockdep_assert_held(&ctx->mutex); 280 } 281 282 if (!task) { 283 cpu_function_call(event->cpu, event_function, &efs); 284 return; 285 } 286 287 if (task == TASK_TOMBSTONE) 288 return; 289 290 again: 291 if (!task_function_call(task, event_function, &efs)) 292 return; 293 294 raw_spin_lock_irq(&ctx->lock); 295 /* 296 * Reload the task pointer, it might have been changed by 297 * a concurrent perf_event_context_sched_out(). 298 */ 299 task = ctx->task; 300 if (task == TASK_TOMBSTONE) { 301 raw_spin_unlock_irq(&ctx->lock); 302 return; 303 } 304 if (ctx->is_active) { 305 raw_spin_unlock_irq(&ctx->lock); 306 goto again; 307 } 308 func(event, NULL, ctx, data); 309 raw_spin_unlock_irq(&ctx->lock); 310 } 311 312 /* 313 * Similar to event_function_call() + event_function(), but hard assumes IRQs 314 * are already disabled and we're on the right CPU. 315 */ 316 static void event_function_local(struct perf_event *event, event_f func, void *data) 317 { 318 struct perf_event_context *ctx = event->ctx; 319 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); 320 struct task_struct *task = READ_ONCE(ctx->task); 321 struct perf_event_context *task_ctx = NULL; 322 323 lockdep_assert_irqs_disabled(); 324 325 if (task) { 326 if (task == TASK_TOMBSTONE) 327 return; 328 329 task_ctx = ctx; 330 } 331 332 perf_ctx_lock(cpuctx, task_ctx); 333 334 task = ctx->task; 335 if (task == TASK_TOMBSTONE) 336 goto unlock; 337 338 if (task) { 339 /* 340 * We must be either inactive or active and the right task, 341 * otherwise we're screwed, since we cannot IPI to somewhere 342 * else. 343 */ 344 if (ctx->is_active) { 345 if (WARN_ON_ONCE(task != current)) 346 goto unlock; 347 348 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx)) 349 goto unlock; 350 } 351 } else { 352 WARN_ON_ONCE(&cpuctx->ctx != ctx); 353 } 354 355 func(event, cpuctx, ctx, data); 356 unlock: 357 perf_ctx_unlock(cpuctx, task_ctx); 358 } 359 360 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\ 361 PERF_FLAG_FD_OUTPUT |\ 362 PERF_FLAG_PID_CGROUP |\ 363 PERF_FLAG_FD_CLOEXEC) 364 365 /* 366 * branch priv levels that need permission checks 367 */ 368 #define PERF_SAMPLE_BRANCH_PERM_PLM \ 369 (PERF_SAMPLE_BRANCH_KERNEL |\ 370 PERF_SAMPLE_BRANCH_HV) 371 372 enum event_type_t { 373 EVENT_FLEXIBLE = 0x1, 374 EVENT_PINNED = 0x2, 375 EVENT_TIME = 0x4, 376 /* see ctx_resched() for details */ 377 EVENT_CPU = 0x8, 378 EVENT_CGROUP = 0x10, 379 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED, 380 }; 381 382 /* 383 * perf_sched_events : >0 events exist 384 */ 385 386 static void perf_sched_delayed(struct work_struct *work); 387 DEFINE_STATIC_KEY_FALSE(perf_sched_events); 388 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed); 389 static DEFINE_MUTEX(perf_sched_mutex); 390 static atomic_t perf_sched_count; 391 392 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events); 393 394 static atomic_t nr_mmap_events __read_mostly; 395 static atomic_t nr_comm_events __read_mostly; 396 static atomic_t nr_namespaces_events __read_mostly; 397 static atomic_t nr_task_events __read_mostly; 398 static atomic_t nr_freq_events __read_mostly; 399 static atomic_t nr_switch_events __read_mostly; 400 static atomic_t nr_ksymbol_events __read_mostly; 401 static atomic_t nr_bpf_events __read_mostly; 402 static atomic_t nr_cgroup_events __read_mostly; 403 static atomic_t nr_text_poke_events __read_mostly; 404 static atomic_t nr_build_id_events __read_mostly; 405 406 static LIST_HEAD(pmus); 407 static DEFINE_MUTEX(pmus_lock); 408 static struct srcu_struct pmus_srcu; 409 static cpumask_var_t perf_online_mask; 410 static struct kmem_cache *perf_event_cache; 411 412 /* 413 * perf event paranoia level: 414 * -1 - not paranoid at all 415 * 0 - disallow raw tracepoint access for unpriv 416 * 1 - disallow cpu events for unpriv 417 * 2 - disallow kernel profiling for unpriv 418 */ 419 int sysctl_perf_event_paranoid __read_mostly = 2; 420 421 /* Minimum for 512 kiB + 1 user control page */ 422 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */ 423 424 /* 425 * max perf event sample rate 426 */ 427 #define DEFAULT_MAX_SAMPLE_RATE 100000 428 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE) 429 #define DEFAULT_CPU_TIME_MAX_PERCENT 25 430 431 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE; 432 433 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ); 434 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS; 435 436 static int perf_sample_allowed_ns __read_mostly = 437 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100; 438 439 static void update_perf_cpu_limits(void) 440 { 441 u64 tmp = perf_sample_period_ns; 442 443 tmp *= sysctl_perf_cpu_time_max_percent; 444 tmp = div_u64(tmp, 100); 445 if (!tmp) 446 tmp = 1; 447 448 WRITE_ONCE(perf_sample_allowed_ns, tmp); 449 } 450 451 static bool perf_rotate_context(struct perf_cpu_pmu_context *cpc); 452 453 int perf_event_max_sample_rate_handler(struct ctl_table *table, int write, 454 void *buffer, size_t *lenp, loff_t *ppos) 455 { 456 int ret; 457 int perf_cpu = sysctl_perf_cpu_time_max_percent; 458 /* 459 * If throttling is disabled don't allow the write: 460 */ 461 if (write && (perf_cpu == 100 || perf_cpu == 0)) 462 return -EINVAL; 463 464 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); 465 if (ret || !write) 466 return ret; 467 468 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ); 469 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; 470 update_perf_cpu_limits(); 471 472 return 0; 473 } 474 475 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT; 476 477 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write, 478 void *buffer, size_t *lenp, loff_t *ppos) 479 { 480 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); 481 482 if (ret || !write) 483 return ret; 484 485 if (sysctl_perf_cpu_time_max_percent == 100 || 486 sysctl_perf_cpu_time_max_percent == 0) { 487 printk(KERN_WARNING 488 "perf: Dynamic interrupt throttling disabled, can hang your system!\n"); 489 WRITE_ONCE(perf_sample_allowed_ns, 0); 490 } else { 491 update_perf_cpu_limits(); 492 } 493 494 return 0; 495 } 496 497 /* 498 * perf samples are done in some very critical code paths (NMIs). 499 * If they take too much CPU time, the system can lock up and not 500 * get any real work done. This will drop the sample rate when 501 * we detect that events are taking too long. 502 */ 503 #define NR_ACCUMULATED_SAMPLES 128 504 static DEFINE_PER_CPU(u64, running_sample_length); 505 506 static u64 __report_avg; 507 static u64 __report_allowed; 508 509 static void perf_duration_warn(struct irq_work *w) 510 { 511 printk_ratelimited(KERN_INFO 512 "perf: interrupt took too long (%lld > %lld), lowering " 513 "kernel.perf_event_max_sample_rate to %d\n", 514 __report_avg, __report_allowed, 515 sysctl_perf_event_sample_rate); 516 } 517 518 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn); 519 520 void perf_sample_event_took(u64 sample_len_ns) 521 { 522 u64 max_len = READ_ONCE(perf_sample_allowed_ns); 523 u64 running_len; 524 u64 avg_len; 525 u32 max; 526 527 if (max_len == 0) 528 return; 529 530 /* Decay the counter by 1 average sample. */ 531 running_len = __this_cpu_read(running_sample_length); 532 running_len -= running_len/NR_ACCUMULATED_SAMPLES; 533 running_len += sample_len_ns; 534 __this_cpu_write(running_sample_length, running_len); 535 536 /* 537 * Note: this will be biased artifically low until we have 538 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us 539 * from having to maintain a count. 540 */ 541 avg_len = running_len/NR_ACCUMULATED_SAMPLES; 542 if (avg_len <= max_len) 543 return; 544 545 __report_avg = avg_len; 546 __report_allowed = max_len; 547 548 /* 549 * Compute a throttle threshold 25% below the current duration. 550 */ 551 avg_len += avg_len / 4; 552 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent; 553 if (avg_len < max) 554 max /= (u32)avg_len; 555 else 556 max = 1; 557 558 WRITE_ONCE(perf_sample_allowed_ns, avg_len); 559 WRITE_ONCE(max_samples_per_tick, max); 560 561 sysctl_perf_event_sample_rate = max * HZ; 562 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; 563 564 if (!irq_work_queue(&perf_duration_work)) { 565 early_printk("perf: interrupt took too long (%lld > %lld), lowering " 566 "kernel.perf_event_max_sample_rate to %d\n", 567 __report_avg, __report_allowed, 568 sysctl_perf_event_sample_rate); 569 } 570 } 571 572 static atomic64_t perf_event_id; 573 574 static void update_context_time(struct perf_event_context *ctx); 575 static u64 perf_event_time(struct perf_event *event); 576 577 void __weak perf_event_print_debug(void) { } 578 579 static inline u64 perf_clock(void) 580 { 581 return local_clock(); 582 } 583 584 static inline u64 perf_event_clock(struct perf_event *event) 585 { 586 return event->clock(); 587 } 588 589 /* 590 * State based event timekeeping... 591 * 592 * The basic idea is to use event->state to determine which (if any) time 593 * fields to increment with the current delta. This means we only need to 594 * update timestamps when we change state or when they are explicitly requested 595 * (read). 596 * 597 * Event groups make things a little more complicated, but not terribly so. The 598 * rules for a group are that if the group leader is OFF the entire group is 599 * OFF, irrespecive of what the group member states are. This results in 600 * __perf_effective_state(). 601 * 602 * A futher ramification is that when a group leader flips between OFF and 603 * !OFF, we need to update all group member times. 604 * 605 * 606 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we 607 * need to make sure the relevant context time is updated before we try and 608 * update our timestamps. 609 */ 610 611 static __always_inline enum perf_event_state 612 __perf_effective_state(struct perf_event *event) 613 { 614 struct perf_event *leader = event->group_leader; 615 616 if (leader->state <= PERF_EVENT_STATE_OFF) 617 return leader->state; 618 619 return event->state; 620 } 621 622 static __always_inline void 623 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running) 624 { 625 enum perf_event_state state = __perf_effective_state(event); 626 u64 delta = now - event->tstamp; 627 628 *enabled = event->total_time_enabled; 629 if (state >= PERF_EVENT_STATE_INACTIVE) 630 *enabled += delta; 631 632 *running = event->total_time_running; 633 if (state >= PERF_EVENT_STATE_ACTIVE) 634 *running += delta; 635 } 636 637 static void perf_event_update_time(struct perf_event *event) 638 { 639 u64 now = perf_event_time(event); 640 641 __perf_update_times(event, now, &event->total_time_enabled, 642 &event->total_time_running); 643 event->tstamp = now; 644 } 645 646 static void perf_event_update_sibling_time(struct perf_event *leader) 647 { 648 struct perf_event *sibling; 649 650 for_each_sibling_event(sibling, leader) 651 perf_event_update_time(sibling); 652 } 653 654 static void 655 perf_event_set_state(struct perf_event *event, enum perf_event_state state) 656 { 657 if (event->state == state) 658 return; 659 660 perf_event_update_time(event); 661 /* 662 * If a group leader gets enabled/disabled all its siblings 663 * are affected too. 664 */ 665 if ((event->state < 0) ^ (state < 0)) 666 perf_event_update_sibling_time(event); 667 668 WRITE_ONCE(event->state, state); 669 } 670 671 /* 672 * UP store-release, load-acquire 673 */ 674 675 #define __store_release(ptr, val) \ 676 do { \ 677 barrier(); \ 678 WRITE_ONCE(*(ptr), (val)); \ 679 } while (0) 680 681 #define __load_acquire(ptr) \ 682 ({ \ 683 __unqual_scalar_typeof(*(ptr)) ___p = READ_ONCE(*(ptr)); \ 684 barrier(); \ 685 ___p; \ 686 }) 687 688 static void perf_ctx_disable(struct perf_event_context *ctx, bool cgroup) 689 { 690 struct perf_event_pmu_context *pmu_ctx; 691 692 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) { 693 if (cgroup && !pmu_ctx->nr_cgroups) 694 continue; 695 perf_pmu_disable(pmu_ctx->pmu); 696 } 697 } 698 699 static void perf_ctx_enable(struct perf_event_context *ctx, bool cgroup) 700 { 701 struct perf_event_pmu_context *pmu_ctx; 702 703 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) { 704 if (cgroup && !pmu_ctx->nr_cgroups) 705 continue; 706 perf_pmu_enable(pmu_ctx->pmu); 707 } 708 } 709 710 static void ctx_sched_out(struct perf_event_context *ctx, enum event_type_t event_type); 711 static void ctx_sched_in(struct perf_event_context *ctx, enum event_type_t event_type); 712 713 #ifdef CONFIG_CGROUP_PERF 714 715 static inline bool 716 perf_cgroup_match(struct perf_event *event) 717 { 718 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); 719 720 /* @event doesn't care about cgroup */ 721 if (!event->cgrp) 722 return true; 723 724 /* wants specific cgroup scope but @cpuctx isn't associated with any */ 725 if (!cpuctx->cgrp) 726 return false; 727 728 /* 729 * Cgroup scoping is recursive. An event enabled for a cgroup is 730 * also enabled for all its descendant cgroups. If @cpuctx's 731 * cgroup is a descendant of @event's (the test covers identity 732 * case), it's a match. 733 */ 734 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup, 735 event->cgrp->css.cgroup); 736 } 737 738 static inline void perf_detach_cgroup(struct perf_event *event) 739 { 740 css_put(&event->cgrp->css); 741 event->cgrp = NULL; 742 } 743 744 static inline int is_cgroup_event(struct perf_event *event) 745 { 746 return event->cgrp != NULL; 747 } 748 749 static inline u64 perf_cgroup_event_time(struct perf_event *event) 750 { 751 struct perf_cgroup_info *t; 752 753 t = per_cpu_ptr(event->cgrp->info, event->cpu); 754 return t->time; 755 } 756 757 static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now) 758 { 759 struct perf_cgroup_info *t; 760 761 t = per_cpu_ptr(event->cgrp->info, event->cpu); 762 if (!__load_acquire(&t->active)) 763 return t->time; 764 now += READ_ONCE(t->timeoffset); 765 return now; 766 } 767 768 static inline void __update_cgrp_time(struct perf_cgroup_info *info, u64 now, bool adv) 769 { 770 if (adv) 771 info->time += now - info->timestamp; 772 info->timestamp = now; 773 /* 774 * see update_context_time() 775 */ 776 WRITE_ONCE(info->timeoffset, info->time - info->timestamp); 777 } 778 779 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx, bool final) 780 { 781 struct perf_cgroup *cgrp = cpuctx->cgrp; 782 struct cgroup_subsys_state *css; 783 struct perf_cgroup_info *info; 784 785 if (cgrp) { 786 u64 now = perf_clock(); 787 788 for (css = &cgrp->css; css; css = css->parent) { 789 cgrp = container_of(css, struct perf_cgroup, css); 790 info = this_cpu_ptr(cgrp->info); 791 792 __update_cgrp_time(info, now, true); 793 if (final) 794 __store_release(&info->active, 0); 795 } 796 } 797 } 798 799 static inline void update_cgrp_time_from_event(struct perf_event *event) 800 { 801 struct perf_cgroup_info *info; 802 803 /* 804 * ensure we access cgroup data only when needed and 805 * when we know the cgroup is pinned (css_get) 806 */ 807 if (!is_cgroup_event(event)) 808 return; 809 810 info = this_cpu_ptr(event->cgrp->info); 811 /* 812 * Do not update time when cgroup is not active 813 */ 814 if (info->active) 815 __update_cgrp_time(info, perf_clock(), true); 816 } 817 818 static inline void 819 perf_cgroup_set_timestamp(struct perf_cpu_context *cpuctx) 820 { 821 struct perf_event_context *ctx = &cpuctx->ctx; 822 struct perf_cgroup *cgrp = cpuctx->cgrp; 823 struct perf_cgroup_info *info; 824 struct cgroup_subsys_state *css; 825 826 /* 827 * ctx->lock held by caller 828 * ensure we do not access cgroup data 829 * unless we have the cgroup pinned (css_get) 830 */ 831 if (!cgrp) 832 return; 833 834 WARN_ON_ONCE(!ctx->nr_cgroups); 835 836 for (css = &cgrp->css; css; css = css->parent) { 837 cgrp = container_of(css, struct perf_cgroup, css); 838 info = this_cpu_ptr(cgrp->info); 839 __update_cgrp_time(info, ctx->timestamp, false); 840 __store_release(&info->active, 1); 841 } 842 } 843 844 /* 845 * reschedule events based on the cgroup constraint of task. 846 */ 847 static void perf_cgroup_switch(struct task_struct *task) 848 { 849 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); 850 struct perf_cgroup *cgrp; 851 852 /* 853 * cpuctx->cgrp is set when the first cgroup event enabled, 854 * and is cleared when the last cgroup event disabled. 855 */ 856 if (READ_ONCE(cpuctx->cgrp) == NULL) 857 return; 858 859 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0); 860 861 cgrp = perf_cgroup_from_task(task, NULL); 862 if (READ_ONCE(cpuctx->cgrp) == cgrp) 863 return; 864 865 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 866 perf_ctx_disable(&cpuctx->ctx, true); 867 868 ctx_sched_out(&cpuctx->ctx, EVENT_ALL|EVENT_CGROUP); 869 /* 870 * must not be done before ctxswout due 871 * to update_cgrp_time_from_cpuctx() in 872 * ctx_sched_out() 873 */ 874 cpuctx->cgrp = cgrp; 875 /* 876 * set cgrp before ctxsw in to allow 877 * perf_cgroup_set_timestamp() in ctx_sched_in() 878 * to not have to pass task around 879 */ 880 ctx_sched_in(&cpuctx->ctx, EVENT_ALL|EVENT_CGROUP); 881 882 perf_ctx_enable(&cpuctx->ctx, true); 883 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 884 } 885 886 static int perf_cgroup_ensure_storage(struct perf_event *event, 887 struct cgroup_subsys_state *css) 888 { 889 struct perf_cpu_context *cpuctx; 890 struct perf_event **storage; 891 int cpu, heap_size, ret = 0; 892 893 /* 894 * Allow storage to have sufficent space for an iterator for each 895 * possibly nested cgroup plus an iterator for events with no cgroup. 896 */ 897 for (heap_size = 1; css; css = css->parent) 898 heap_size++; 899 900 for_each_possible_cpu(cpu) { 901 cpuctx = per_cpu_ptr(&perf_cpu_context, cpu); 902 if (heap_size <= cpuctx->heap_size) 903 continue; 904 905 storage = kmalloc_node(heap_size * sizeof(struct perf_event *), 906 GFP_KERNEL, cpu_to_node(cpu)); 907 if (!storage) { 908 ret = -ENOMEM; 909 break; 910 } 911 912 raw_spin_lock_irq(&cpuctx->ctx.lock); 913 if (cpuctx->heap_size < heap_size) { 914 swap(cpuctx->heap, storage); 915 if (storage == cpuctx->heap_default) 916 storage = NULL; 917 cpuctx->heap_size = heap_size; 918 } 919 raw_spin_unlock_irq(&cpuctx->ctx.lock); 920 921 kfree(storage); 922 } 923 924 return ret; 925 } 926 927 static inline int perf_cgroup_connect(int fd, struct perf_event *event, 928 struct perf_event_attr *attr, 929 struct perf_event *group_leader) 930 { 931 struct perf_cgroup *cgrp; 932 struct cgroup_subsys_state *css; 933 struct fd f = fdget(fd); 934 int ret = 0; 935 936 if (!f.file) 937 return -EBADF; 938 939 css = css_tryget_online_from_dir(f.file->f_path.dentry, 940 &perf_event_cgrp_subsys); 941 if (IS_ERR(css)) { 942 ret = PTR_ERR(css); 943 goto out; 944 } 945 946 ret = perf_cgroup_ensure_storage(event, css); 947 if (ret) 948 goto out; 949 950 cgrp = container_of(css, struct perf_cgroup, css); 951 event->cgrp = cgrp; 952 953 /* 954 * all events in a group must monitor 955 * the same cgroup because a task belongs 956 * to only one perf cgroup at a time 957 */ 958 if (group_leader && group_leader->cgrp != cgrp) { 959 perf_detach_cgroup(event); 960 ret = -EINVAL; 961 } 962 out: 963 fdput(f); 964 return ret; 965 } 966 967 static inline void 968 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx) 969 { 970 struct perf_cpu_context *cpuctx; 971 972 if (!is_cgroup_event(event)) 973 return; 974 975 event->pmu_ctx->nr_cgroups++; 976 977 /* 978 * Because cgroup events are always per-cpu events, 979 * @ctx == &cpuctx->ctx. 980 */ 981 cpuctx = container_of(ctx, struct perf_cpu_context, ctx); 982 983 if (ctx->nr_cgroups++) 984 return; 985 986 cpuctx->cgrp = perf_cgroup_from_task(current, ctx); 987 } 988 989 static inline void 990 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx) 991 { 992 struct perf_cpu_context *cpuctx; 993 994 if (!is_cgroup_event(event)) 995 return; 996 997 event->pmu_ctx->nr_cgroups--; 998 999 /* 1000 * Because cgroup events are always per-cpu events, 1001 * @ctx == &cpuctx->ctx. 1002 */ 1003 cpuctx = container_of(ctx, struct perf_cpu_context, ctx); 1004 1005 if (--ctx->nr_cgroups) 1006 return; 1007 1008 cpuctx->cgrp = NULL; 1009 } 1010 1011 #else /* !CONFIG_CGROUP_PERF */ 1012 1013 static inline bool 1014 perf_cgroup_match(struct perf_event *event) 1015 { 1016 return true; 1017 } 1018 1019 static inline void perf_detach_cgroup(struct perf_event *event) 1020 {} 1021 1022 static inline int is_cgroup_event(struct perf_event *event) 1023 { 1024 return 0; 1025 } 1026 1027 static inline void update_cgrp_time_from_event(struct perf_event *event) 1028 { 1029 } 1030 1031 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx, 1032 bool final) 1033 { 1034 } 1035 1036 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event, 1037 struct perf_event_attr *attr, 1038 struct perf_event *group_leader) 1039 { 1040 return -EINVAL; 1041 } 1042 1043 static inline void 1044 perf_cgroup_set_timestamp(struct perf_cpu_context *cpuctx) 1045 { 1046 } 1047 1048 static inline u64 perf_cgroup_event_time(struct perf_event *event) 1049 { 1050 return 0; 1051 } 1052 1053 static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now) 1054 { 1055 return 0; 1056 } 1057 1058 static inline void 1059 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx) 1060 { 1061 } 1062 1063 static inline void 1064 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx) 1065 { 1066 } 1067 1068 static void perf_cgroup_switch(struct task_struct *task) 1069 { 1070 } 1071 #endif 1072 1073 /* 1074 * set default to be dependent on timer tick just 1075 * like original code 1076 */ 1077 #define PERF_CPU_HRTIMER (1000 / HZ) 1078 /* 1079 * function must be called with interrupts disabled 1080 */ 1081 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr) 1082 { 1083 struct perf_cpu_pmu_context *cpc; 1084 bool rotations; 1085 1086 lockdep_assert_irqs_disabled(); 1087 1088 cpc = container_of(hr, struct perf_cpu_pmu_context, hrtimer); 1089 rotations = perf_rotate_context(cpc); 1090 1091 raw_spin_lock(&cpc->hrtimer_lock); 1092 if (rotations) 1093 hrtimer_forward_now(hr, cpc->hrtimer_interval); 1094 else 1095 cpc->hrtimer_active = 0; 1096 raw_spin_unlock(&cpc->hrtimer_lock); 1097 1098 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART; 1099 } 1100 1101 static void __perf_mux_hrtimer_init(struct perf_cpu_pmu_context *cpc, int cpu) 1102 { 1103 struct hrtimer *timer = &cpc->hrtimer; 1104 struct pmu *pmu = cpc->epc.pmu; 1105 u64 interval; 1106 1107 /* 1108 * check default is sane, if not set then force to 1109 * default interval (1/tick) 1110 */ 1111 interval = pmu->hrtimer_interval_ms; 1112 if (interval < 1) 1113 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER; 1114 1115 cpc->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval); 1116 1117 raw_spin_lock_init(&cpc->hrtimer_lock); 1118 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD); 1119 timer->function = perf_mux_hrtimer_handler; 1120 } 1121 1122 static int perf_mux_hrtimer_restart(struct perf_cpu_pmu_context *cpc) 1123 { 1124 struct hrtimer *timer = &cpc->hrtimer; 1125 unsigned long flags; 1126 1127 raw_spin_lock_irqsave(&cpc->hrtimer_lock, flags); 1128 if (!cpc->hrtimer_active) { 1129 cpc->hrtimer_active = 1; 1130 hrtimer_forward_now(timer, cpc->hrtimer_interval); 1131 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD); 1132 } 1133 raw_spin_unlock_irqrestore(&cpc->hrtimer_lock, flags); 1134 1135 return 0; 1136 } 1137 1138 static int perf_mux_hrtimer_restart_ipi(void *arg) 1139 { 1140 return perf_mux_hrtimer_restart(arg); 1141 } 1142 1143 void perf_pmu_disable(struct pmu *pmu) 1144 { 1145 int *count = this_cpu_ptr(pmu->pmu_disable_count); 1146 if (!(*count)++) 1147 pmu->pmu_disable(pmu); 1148 } 1149 1150 void perf_pmu_enable(struct pmu *pmu) 1151 { 1152 int *count = this_cpu_ptr(pmu->pmu_disable_count); 1153 if (!--(*count)) 1154 pmu->pmu_enable(pmu); 1155 } 1156 1157 static void perf_assert_pmu_disabled(struct pmu *pmu) 1158 { 1159 WARN_ON_ONCE(*this_cpu_ptr(pmu->pmu_disable_count) == 0); 1160 } 1161 1162 static void get_ctx(struct perf_event_context *ctx) 1163 { 1164 refcount_inc(&ctx->refcount); 1165 } 1166 1167 static void *alloc_task_ctx_data(struct pmu *pmu) 1168 { 1169 if (pmu->task_ctx_cache) 1170 return kmem_cache_zalloc(pmu->task_ctx_cache, GFP_KERNEL); 1171 1172 return NULL; 1173 } 1174 1175 static void free_task_ctx_data(struct pmu *pmu, void *task_ctx_data) 1176 { 1177 if (pmu->task_ctx_cache && task_ctx_data) 1178 kmem_cache_free(pmu->task_ctx_cache, task_ctx_data); 1179 } 1180 1181 static void free_ctx(struct rcu_head *head) 1182 { 1183 struct perf_event_context *ctx; 1184 1185 ctx = container_of(head, struct perf_event_context, rcu_head); 1186 kfree(ctx); 1187 } 1188 1189 static void put_ctx(struct perf_event_context *ctx) 1190 { 1191 if (refcount_dec_and_test(&ctx->refcount)) { 1192 if (ctx->parent_ctx) 1193 put_ctx(ctx->parent_ctx); 1194 if (ctx->task && ctx->task != TASK_TOMBSTONE) 1195 put_task_struct(ctx->task); 1196 call_rcu(&ctx->rcu_head, free_ctx); 1197 } 1198 } 1199 1200 /* 1201 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and 1202 * perf_pmu_migrate_context() we need some magic. 1203 * 1204 * Those places that change perf_event::ctx will hold both 1205 * perf_event_ctx::mutex of the 'old' and 'new' ctx value. 1206 * 1207 * Lock ordering is by mutex address. There are two other sites where 1208 * perf_event_context::mutex nests and those are: 1209 * 1210 * - perf_event_exit_task_context() [ child , 0 ] 1211 * perf_event_exit_event() 1212 * put_event() [ parent, 1 ] 1213 * 1214 * - perf_event_init_context() [ parent, 0 ] 1215 * inherit_task_group() 1216 * inherit_group() 1217 * inherit_event() 1218 * perf_event_alloc() 1219 * perf_init_event() 1220 * perf_try_init_event() [ child , 1 ] 1221 * 1222 * While it appears there is an obvious deadlock here -- the parent and child 1223 * nesting levels are inverted between the two. This is in fact safe because 1224 * life-time rules separate them. That is an exiting task cannot fork, and a 1225 * spawning task cannot (yet) exit. 1226 * 1227 * But remember that these are parent<->child context relations, and 1228 * migration does not affect children, therefore these two orderings should not 1229 * interact. 1230 * 1231 * The change in perf_event::ctx does not affect children (as claimed above) 1232 * because the sys_perf_event_open() case will install a new event and break 1233 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only 1234 * concerned with cpuctx and that doesn't have children. 1235 * 1236 * The places that change perf_event::ctx will issue: 1237 * 1238 * perf_remove_from_context(); 1239 * synchronize_rcu(); 1240 * perf_install_in_context(); 1241 * 1242 * to affect the change. The remove_from_context() + synchronize_rcu() should 1243 * quiesce the event, after which we can install it in the new location. This 1244 * means that only external vectors (perf_fops, prctl) can perturb the event 1245 * while in transit. Therefore all such accessors should also acquire 1246 * perf_event_context::mutex to serialize against this. 1247 * 1248 * However; because event->ctx can change while we're waiting to acquire 1249 * ctx->mutex we must be careful and use the below perf_event_ctx_lock() 1250 * function. 1251 * 1252 * Lock order: 1253 * exec_update_lock 1254 * task_struct::perf_event_mutex 1255 * perf_event_context::mutex 1256 * perf_event::child_mutex; 1257 * perf_event_context::lock 1258 * perf_event::mmap_mutex 1259 * mmap_lock 1260 * perf_addr_filters_head::lock 1261 * 1262 * cpu_hotplug_lock 1263 * pmus_lock 1264 * cpuctx->mutex / perf_event_context::mutex 1265 */ 1266 static struct perf_event_context * 1267 perf_event_ctx_lock_nested(struct perf_event *event, int nesting) 1268 { 1269 struct perf_event_context *ctx; 1270 1271 again: 1272 rcu_read_lock(); 1273 ctx = READ_ONCE(event->ctx); 1274 if (!refcount_inc_not_zero(&ctx->refcount)) { 1275 rcu_read_unlock(); 1276 goto again; 1277 } 1278 rcu_read_unlock(); 1279 1280 mutex_lock_nested(&ctx->mutex, nesting); 1281 if (event->ctx != ctx) { 1282 mutex_unlock(&ctx->mutex); 1283 put_ctx(ctx); 1284 goto again; 1285 } 1286 1287 return ctx; 1288 } 1289 1290 static inline struct perf_event_context * 1291 perf_event_ctx_lock(struct perf_event *event) 1292 { 1293 return perf_event_ctx_lock_nested(event, 0); 1294 } 1295 1296 static void perf_event_ctx_unlock(struct perf_event *event, 1297 struct perf_event_context *ctx) 1298 { 1299 mutex_unlock(&ctx->mutex); 1300 put_ctx(ctx); 1301 } 1302 1303 /* 1304 * This must be done under the ctx->lock, such as to serialize against 1305 * context_equiv(), therefore we cannot call put_ctx() since that might end up 1306 * calling scheduler related locks and ctx->lock nests inside those. 1307 */ 1308 static __must_check struct perf_event_context * 1309 unclone_ctx(struct perf_event_context *ctx) 1310 { 1311 struct perf_event_context *parent_ctx = ctx->parent_ctx; 1312 1313 lockdep_assert_held(&ctx->lock); 1314 1315 if (parent_ctx) 1316 ctx->parent_ctx = NULL; 1317 ctx->generation++; 1318 1319 return parent_ctx; 1320 } 1321 1322 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p, 1323 enum pid_type type) 1324 { 1325 u32 nr; 1326 /* 1327 * only top level events have the pid namespace they were created in 1328 */ 1329 if (event->parent) 1330 event = event->parent; 1331 1332 nr = __task_pid_nr_ns(p, type, event->ns); 1333 /* avoid -1 if it is idle thread or runs in another ns */ 1334 if (!nr && !pid_alive(p)) 1335 nr = -1; 1336 return nr; 1337 } 1338 1339 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) 1340 { 1341 return perf_event_pid_type(event, p, PIDTYPE_TGID); 1342 } 1343 1344 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) 1345 { 1346 return perf_event_pid_type(event, p, PIDTYPE_PID); 1347 } 1348 1349 /* 1350 * If we inherit events we want to return the parent event id 1351 * to userspace. 1352 */ 1353 static u64 primary_event_id(struct perf_event *event) 1354 { 1355 u64 id = event->id; 1356 1357 if (event->parent) 1358 id = event->parent->id; 1359 1360 return id; 1361 } 1362 1363 /* 1364 * Get the perf_event_context for a task and lock it. 1365 * 1366 * This has to cope with the fact that until it is locked, 1367 * the context could get moved to another task. 1368 */ 1369 static struct perf_event_context * 1370 perf_lock_task_context(struct task_struct *task, unsigned long *flags) 1371 { 1372 struct perf_event_context *ctx; 1373 1374 retry: 1375 /* 1376 * One of the few rules of preemptible RCU is that one cannot do 1377 * rcu_read_unlock() while holding a scheduler (or nested) lock when 1378 * part of the read side critical section was irqs-enabled -- see 1379 * rcu_read_unlock_special(). 1380 * 1381 * Since ctx->lock nests under rq->lock we must ensure the entire read 1382 * side critical section has interrupts disabled. 1383 */ 1384 local_irq_save(*flags); 1385 rcu_read_lock(); 1386 ctx = rcu_dereference(task->perf_event_ctxp); 1387 if (ctx) { 1388 /* 1389 * If this context is a clone of another, it might 1390 * get swapped for another underneath us by 1391 * perf_event_task_sched_out, though the 1392 * rcu_read_lock() protects us from any context 1393 * getting freed. Lock the context and check if it 1394 * got swapped before we could get the lock, and retry 1395 * if so. If we locked the right context, then it 1396 * can't get swapped on us any more. 1397 */ 1398 raw_spin_lock(&ctx->lock); 1399 if (ctx != rcu_dereference(task->perf_event_ctxp)) { 1400 raw_spin_unlock(&ctx->lock); 1401 rcu_read_unlock(); 1402 local_irq_restore(*flags); 1403 goto retry; 1404 } 1405 1406 if (ctx->task == TASK_TOMBSTONE || 1407 !refcount_inc_not_zero(&ctx->refcount)) { 1408 raw_spin_unlock(&ctx->lock); 1409 ctx = NULL; 1410 } else { 1411 WARN_ON_ONCE(ctx->task != task); 1412 } 1413 } 1414 rcu_read_unlock(); 1415 if (!ctx) 1416 local_irq_restore(*flags); 1417 return ctx; 1418 } 1419 1420 /* 1421 * Get the context for a task and increment its pin_count so it 1422 * can't get swapped to another task. This also increments its 1423 * reference count so that the context can't get freed. 1424 */ 1425 static struct perf_event_context * 1426 perf_pin_task_context(struct task_struct *task) 1427 { 1428 struct perf_event_context *ctx; 1429 unsigned long flags; 1430 1431 ctx = perf_lock_task_context(task, &flags); 1432 if (ctx) { 1433 ++ctx->pin_count; 1434 raw_spin_unlock_irqrestore(&ctx->lock, flags); 1435 } 1436 return ctx; 1437 } 1438 1439 static void perf_unpin_context(struct perf_event_context *ctx) 1440 { 1441 unsigned long flags; 1442 1443 raw_spin_lock_irqsave(&ctx->lock, flags); 1444 --ctx->pin_count; 1445 raw_spin_unlock_irqrestore(&ctx->lock, flags); 1446 } 1447 1448 /* 1449 * Update the record of the current time in a context. 1450 */ 1451 static void __update_context_time(struct perf_event_context *ctx, bool adv) 1452 { 1453 u64 now = perf_clock(); 1454 1455 lockdep_assert_held(&ctx->lock); 1456 1457 if (adv) 1458 ctx->time += now - ctx->timestamp; 1459 ctx->timestamp = now; 1460 1461 /* 1462 * The above: time' = time + (now - timestamp), can be re-arranged 1463 * into: time` = now + (time - timestamp), which gives a single value 1464 * offset to compute future time without locks on. 1465 * 1466 * See perf_event_time_now(), which can be used from NMI context where 1467 * it's (obviously) not possible to acquire ctx->lock in order to read 1468 * both the above values in a consistent manner. 1469 */ 1470 WRITE_ONCE(ctx->timeoffset, ctx->time - ctx->timestamp); 1471 } 1472 1473 static void update_context_time(struct perf_event_context *ctx) 1474 { 1475 __update_context_time(ctx, true); 1476 } 1477 1478 static u64 perf_event_time(struct perf_event *event) 1479 { 1480 struct perf_event_context *ctx = event->ctx; 1481 1482 if (unlikely(!ctx)) 1483 return 0; 1484 1485 if (is_cgroup_event(event)) 1486 return perf_cgroup_event_time(event); 1487 1488 return ctx->time; 1489 } 1490 1491 static u64 perf_event_time_now(struct perf_event *event, u64 now) 1492 { 1493 struct perf_event_context *ctx = event->ctx; 1494 1495 if (unlikely(!ctx)) 1496 return 0; 1497 1498 if (is_cgroup_event(event)) 1499 return perf_cgroup_event_time_now(event, now); 1500 1501 if (!(__load_acquire(&ctx->is_active) & EVENT_TIME)) 1502 return ctx->time; 1503 1504 now += READ_ONCE(ctx->timeoffset); 1505 return now; 1506 } 1507 1508 static enum event_type_t get_event_type(struct perf_event *event) 1509 { 1510 struct perf_event_context *ctx = event->ctx; 1511 enum event_type_t event_type; 1512 1513 lockdep_assert_held(&ctx->lock); 1514 1515 /* 1516 * It's 'group type', really, because if our group leader is 1517 * pinned, so are we. 1518 */ 1519 if (event->group_leader != event) 1520 event = event->group_leader; 1521 1522 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE; 1523 if (!ctx->task) 1524 event_type |= EVENT_CPU; 1525 1526 return event_type; 1527 } 1528 1529 /* 1530 * Helper function to initialize event group nodes. 1531 */ 1532 static void init_event_group(struct perf_event *event) 1533 { 1534 RB_CLEAR_NODE(&event->group_node); 1535 event->group_index = 0; 1536 } 1537 1538 /* 1539 * Extract pinned or flexible groups from the context 1540 * based on event attrs bits. 1541 */ 1542 static struct perf_event_groups * 1543 get_event_groups(struct perf_event *event, struct perf_event_context *ctx) 1544 { 1545 if (event->attr.pinned) 1546 return &ctx->pinned_groups; 1547 else 1548 return &ctx->flexible_groups; 1549 } 1550 1551 /* 1552 * Helper function to initializes perf_event_group trees. 1553 */ 1554 static void perf_event_groups_init(struct perf_event_groups *groups) 1555 { 1556 groups->tree = RB_ROOT; 1557 groups->index = 0; 1558 } 1559 1560 static inline struct cgroup *event_cgroup(const struct perf_event *event) 1561 { 1562 struct cgroup *cgroup = NULL; 1563 1564 #ifdef CONFIG_CGROUP_PERF 1565 if (event->cgrp) 1566 cgroup = event->cgrp->css.cgroup; 1567 #endif 1568 1569 return cgroup; 1570 } 1571 1572 /* 1573 * Compare function for event groups; 1574 * 1575 * Implements complex key that first sorts by CPU and then by virtual index 1576 * which provides ordering when rotating groups for the same CPU. 1577 */ 1578 static __always_inline int 1579 perf_event_groups_cmp(const int left_cpu, const struct pmu *left_pmu, 1580 const struct cgroup *left_cgroup, const u64 left_group_index, 1581 const struct perf_event *right) 1582 { 1583 if (left_cpu < right->cpu) 1584 return -1; 1585 if (left_cpu > right->cpu) 1586 return 1; 1587 1588 if (left_pmu) { 1589 if (left_pmu < right->pmu_ctx->pmu) 1590 return -1; 1591 if (left_pmu > right->pmu_ctx->pmu) 1592 return 1; 1593 } 1594 1595 #ifdef CONFIG_CGROUP_PERF 1596 { 1597 const struct cgroup *right_cgroup = event_cgroup(right); 1598 1599 if (left_cgroup != right_cgroup) { 1600 if (!left_cgroup) { 1601 /* 1602 * Left has no cgroup but right does, no 1603 * cgroups come first. 1604 */ 1605 return -1; 1606 } 1607 if (!right_cgroup) { 1608 /* 1609 * Right has no cgroup but left does, no 1610 * cgroups come first. 1611 */ 1612 return 1; 1613 } 1614 /* Two dissimilar cgroups, order by id. */ 1615 if (cgroup_id(left_cgroup) < cgroup_id(right_cgroup)) 1616 return -1; 1617 1618 return 1; 1619 } 1620 } 1621 #endif 1622 1623 if (left_group_index < right->group_index) 1624 return -1; 1625 if (left_group_index > right->group_index) 1626 return 1; 1627 1628 return 0; 1629 } 1630 1631 #define __node_2_pe(node) \ 1632 rb_entry((node), struct perf_event, group_node) 1633 1634 static inline bool __group_less(struct rb_node *a, const struct rb_node *b) 1635 { 1636 struct perf_event *e = __node_2_pe(a); 1637 return perf_event_groups_cmp(e->cpu, e->pmu_ctx->pmu, event_cgroup(e), 1638 e->group_index, __node_2_pe(b)) < 0; 1639 } 1640 1641 struct __group_key { 1642 int cpu; 1643 struct pmu *pmu; 1644 struct cgroup *cgroup; 1645 }; 1646 1647 static inline int __group_cmp(const void *key, const struct rb_node *node) 1648 { 1649 const struct __group_key *a = key; 1650 const struct perf_event *b = __node_2_pe(node); 1651 1652 /* partial/subtree match: @cpu, @pmu, @cgroup; ignore: @group_index */ 1653 return perf_event_groups_cmp(a->cpu, a->pmu, a->cgroup, b->group_index, b); 1654 } 1655 1656 static inline int 1657 __group_cmp_ignore_cgroup(const void *key, const struct rb_node *node) 1658 { 1659 const struct __group_key *a = key; 1660 const struct perf_event *b = __node_2_pe(node); 1661 1662 /* partial/subtree match: @cpu, @pmu, ignore: @cgroup, @group_index */ 1663 return perf_event_groups_cmp(a->cpu, a->pmu, event_cgroup(b), 1664 b->group_index, b); 1665 } 1666 1667 /* 1668 * Insert @event into @groups' tree; using 1669 * {@event->cpu, @event->pmu_ctx->pmu, event_cgroup(@event), ++@groups->index} 1670 * as key. This places it last inside the {cpu,pmu,cgroup} subtree. 1671 */ 1672 static void 1673 perf_event_groups_insert(struct perf_event_groups *groups, 1674 struct perf_event *event) 1675 { 1676 event->group_index = ++groups->index; 1677 1678 rb_add(&event->group_node, &groups->tree, __group_less); 1679 } 1680 1681 /* 1682 * Helper function to insert event into the pinned or flexible groups. 1683 */ 1684 static void 1685 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx) 1686 { 1687 struct perf_event_groups *groups; 1688 1689 groups = get_event_groups(event, ctx); 1690 perf_event_groups_insert(groups, event); 1691 } 1692 1693 /* 1694 * Delete a group from a tree. 1695 */ 1696 static void 1697 perf_event_groups_delete(struct perf_event_groups *groups, 1698 struct perf_event *event) 1699 { 1700 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) || 1701 RB_EMPTY_ROOT(&groups->tree)); 1702 1703 rb_erase(&event->group_node, &groups->tree); 1704 init_event_group(event); 1705 } 1706 1707 /* 1708 * Helper function to delete event from its groups. 1709 */ 1710 static void 1711 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx) 1712 { 1713 struct perf_event_groups *groups; 1714 1715 groups = get_event_groups(event, ctx); 1716 perf_event_groups_delete(groups, event); 1717 } 1718 1719 /* 1720 * Get the leftmost event in the {cpu,pmu,cgroup} subtree. 1721 */ 1722 static struct perf_event * 1723 perf_event_groups_first(struct perf_event_groups *groups, int cpu, 1724 struct pmu *pmu, struct cgroup *cgrp) 1725 { 1726 struct __group_key key = { 1727 .cpu = cpu, 1728 .pmu = pmu, 1729 .cgroup = cgrp, 1730 }; 1731 struct rb_node *node; 1732 1733 node = rb_find_first(&key, &groups->tree, __group_cmp); 1734 if (node) 1735 return __node_2_pe(node); 1736 1737 return NULL; 1738 } 1739 1740 static struct perf_event * 1741 perf_event_groups_next(struct perf_event *event, struct pmu *pmu) 1742 { 1743 struct __group_key key = { 1744 .cpu = event->cpu, 1745 .pmu = pmu, 1746 .cgroup = event_cgroup(event), 1747 }; 1748 struct rb_node *next; 1749 1750 next = rb_next_match(&key, &event->group_node, __group_cmp); 1751 if (next) 1752 return __node_2_pe(next); 1753 1754 return NULL; 1755 } 1756 1757 #define perf_event_groups_for_cpu_pmu(event, groups, cpu, pmu) \ 1758 for (event = perf_event_groups_first(groups, cpu, pmu, NULL); \ 1759 event; event = perf_event_groups_next(event, pmu)) 1760 1761 /* 1762 * Iterate through the whole groups tree. 1763 */ 1764 #define perf_event_groups_for_each(event, groups) \ 1765 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \ 1766 typeof(*event), group_node); event; \ 1767 event = rb_entry_safe(rb_next(&event->group_node), \ 1768 typeof(*event), group_node)) 1769 1770 /* 1771 * Add an event from the lists for its context. 1772 * Must be called with ctx->mutex and ctx->lock held. 1773 */ 1774 static void 1775 list_add_event(struct perf_event *event, struct perf_event_context *ctx) 1776 { 1777 lockdep_assert_held(&ctx->lock); 1778 1779 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); 1780 event->attach_state |= PERF_ATTACH_CONTEXT; 1781 1782 event->tstamp = perf_event_time(event); 1783 1784 /* 1785 * If we're a stand alone event or group leader, we go to the context 1786 * list, group events are kept attached to the group so that 1787 * perf_group_detach can, at all times, locate all siblings. 1788 */ 1789 if (event->group_leader == event) { 1790 event->group_caps = event->event_caps; 1791 add_event_to_groups(event, ctx); 1792 } 1793 1794 list_add_rcu(&event->event_entry, &ctx->event_list); 1795 ctx->nr_events++; 1796 if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT) 1797 ctx->nr_user++; 1798 if (event->attr.inherit_stat) 1799 ctx->nr_stat++; 1800 1801 if (event->state > PERF_EVENT_STATE_OFF) 1802 perf_cgroup_event_enable(event, ctx); 1803 1804 ctx->generation++; 1805 event->pmu_ctx->nr_events++; 1806 } 1807 1808 /* 1809 * Initialize event state based on the perf_event_attr::disabled. 1810 */ 1811 static inline void perf_event__state_init(struct perf_event *event) 1812 { 1813 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF : 1814 PERF_EVENT_STATE_INACTIVE; 1815 } 1816 1817 static int __perf_event_read_size(u64 read_format, int nr_siblings) 1818 { 1819 int entry = sizeof(u64); /* value */ 1820 int size = 0; 1821 int nr = 1; 1822 1823 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 1824 size += sizeof(u64); 1825 1826 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 1827 size += sizeof(u64); 1828 1829 if (read_format & PERF_FORMAT_ID) 1830 entry += sizeof(u64); 1831 1832 if (read_format & PERF_FORMAT_LOST) 1833 entry += sizeof(u64); 1834 1835 if (read_format & PERF_FORMAT_GROUP) { 1836 nr += nr_siblings; 1837 size += sizeof(u64); 1838 } 1839 1840 /* 1841 * Since perf_event_validate_size() limits this to 16k and inhibits 1842 * adding more siblings, this will never overflow. 1843 */ 1844 return size + nr * entry; 1845 } 1846 1847 static void __perf_event_header_size(struct perf_event *event, u64 sample_type) 1848 { 1849 struct perf_sample_data *data; 1850 u16 size = 0; 1851 1852 if (sample_type & PERF_SAMPLE_IP) 1853 size += sizeof(data->ip); 1854 1855 if (sample_type & PERF_SAMPLE_ADDR) 1856 size += sizeof(data->addr); 1857 1858 if (sample_type & PERF_SAMPLE_PERIOD) 1859 size += sizeof(data->period); 1860 1861 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE) 1862 size += sizeof(data->weight.full); 1863 1864 if (sample_type & PERF_SAMPLE_READ) 1865 size += event->read_size; 1866 1867 if (sample_type & PERF_SAMPLE_DATA_SRC) 1868 size += sizeof(data->data_src.val); 1869 1870 if (sample_type & PERF_SAMPLE_TRANSACTION) 1871 size += sizeof(data->txn); 1872 1873 if (sample_type & PERF_SAMPLE_PHYS_ADDR) 1874 size += sizeof(data->phys_addr); 1875 1876 if (sample_type & PERF_SAMPLE_CGROUP) 1877 size += sizeof(data->cgroup); 1878 1879 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE) 1880 size += sizeof(data->data_page_size); 1881 1882 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE) 1883 size += sizeof(data->code_page_size); 1884 1885 event->header_size = size; 1886 } 1887 1888 /* 1889 * Called at perf_event creation and when events are attached/detached from a 1890 * group. 1891 */ 1892 static void perf_event__header_size(struct perf_event *event) 1893 { 1894 event->read_size = 1895 __perf_event_read_size(event->attr.read_format, 1896 event->group_leader->nr_siblings); 1897 __perf_event_header_size(event, event->attr.sample_type); 1898 } 1899 1900 static void perf_event__id_header_size(struct perf_event *event) 1901 { 1902 struct perf_sample_data *data; 1903 u64 sample_type = event->attr.sample_type; 1904 u16 size = 0; 1905 1906 if (sample_type & PERF_SAMPLE_TID) 1907 size += sizeof(data->tid_entry); 1908 1909 if (sample_type & PERF_SAMPLE_TIME) 1910 size += sizeof(data->time); 1911 1912 if (sample_type & PERF_SAMPLE_IDENTIFIER) 1913 size += sizeof(data->id); 1914 1915 if (sample_type & PERF_SAMPLE_ID) 1916 size += sizeof(data->id); 1917 1918 if (sample_type & PERF_SAMPLE_STREAM_ID) 1919 size += sizeof(data->stream_id); 1920 1921 if (sample_type & PERF_SAMPLE_CPU) 1922 size += sizeof(data->cpu_entry); 1923 1924 event->id_header_size = size; 1925 } 1926 1927 /* 1928 * Check that adding an event to the group does not result in anybody 1929 * overflowing the 64k event limit imposed by the output buffer. 1930 * 1931 * Specifically, check that the read_size for the event does not exceed 16k, 1932 * read_size being the one term that grows with groups size. Since read_size 1933 * depends on per-event read_format, also (re)check the existing events. 1934 * 1935 * This leaves 48k for the constant size fields and things like callchains, 1936 * branch stacks and register sets. 1937 */ 1938 static bool perf_event_validate_size(struct perf_event *event) 1939 { 1940 struct perf_event *sibling, *group_leader = event->group_leader; 1941 1942 if (__perf_event_read_size(event->attr.read_format, 1943 group_leader->nr_siblings + 1) > 16*1024) 1944 return false; 1945 1946 if (__perf_event_read_size(group_leader->attr.read_format, 1947 group_leader->nr_siblings + 1) > 16*1024) 1948 return false; 1949 1950 /* 1951 * When creating a new group leader, group_leader->ctx is initialized 1952 * after the size has been validated, but we cannot safely use 1953 * for_each_sibling_event() until group_leader->ctx is set. A new group 1954 * leader cannot have any siblings yet, so we can safely skip checking 1955 * the non-existent siblings. 1956 */ 1957 if (event == group_leader) 1958 return true; 1959 1960 for_each_sibling_event(sibling, group_leader) { 1961 if (__perf_event_read_size(sibling->attr.read_format, 1962 group_leader->nr_siblings + 1) > 16*1024) 1963 return false; 1964 } 1965 1966 return true; 1967 } 1968 1969 static void perf_group_attach(struct perf_event *event) 1970 { 1971 struct perf_event *group_leader = event->group_leader, *pos; 1972 1973 lockdep_assert_held(&event->ctx->lock); 1974 1975 /* 1976 * We can have double attach due to group movement (move_group) in 1977 * perf_event_open(). 1978 */ 1979 if (event->attach_state & PERF_ATTACH_GROUP) 1980 return; 1981 1982 event->attach_state |= PERF_ATTACH_GROUP; 1983 1984 if (group_leader == event) 1985 return; 1986 1987 WARN_ON_ONCE(group_leader->ctx != event->ctx); 1988 1989 group_leader->group_caps &= event->event_caps; 1990 1991 list_add_tail(&event->sibling_list, &group_leader->sibling_list); 1992 group_leader->nr_siblings++; 1993 group_leader->group_generation++; 1994 1995 perf_event__header_size(group_leader); 1996 1997 for_each_sibling_event(pos, group_leader) 1998 perf_event__header_size(pos); 1999 } 2000 2001 /* 2002 * Remove an event from the lists for its context. 2003 * Must be called with ctx->mutex and ctx->lock held. 2004 */ 2005 static void 2006 list_del_event(struct perf_event *event, struct perf_event_context *ctx) 2007 { 2008 WARN_ON_ONCE(event->ctx != ctx); 2009 lockdep_assert_held(&ctx->lock); 2010 2011 /* 2012 * We can have double detach due to exit/hot-unplug + close. 2013 */ 2014 if (!(event->attach_state & PERF_ATTACH_CONTEXT)) 2015 return; 2016 2017 event->attach_state &= ~PERF_ATTACH_CONTEXT; 2018 2019 ctx->nr_events--; 2020 if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT) 2021 ctx->nr_user--; 2022 if (event->attr.inherit_stat) 2023 ctx->nr_stat--; 2024 2025 list_del_rcu(&event->event_entry); 2026 2027 if (event->group_leader == event) 2028 del_event_from_groups(event, ctx); 2029 2030 /* 2031 * If event was in error state, then keep it 2032 * that way, otherwise bogus counts will be 2033 * returned on read(). The only way to get out 2034 * of error state is by explicit re-enabling 2035 * of the event 2036 */ 2037 if (event->state > PERF_EVENT_STATE_OFF) { 2038 perf_cgroup_event_disable(event, ctx); 2039 perf_event_set_state(event, PERF_EVENT_STATE_OFF); 2040 } 2041 2042 ctx->generation++; 2043 event->pmu_ctx->nr_events--; 2044 } 2045 2046 static int 2047 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event) 2048 { 2049 if (!has_aux(aux_event)) 2050 return 0; 2051 2052 if (!event->pmu->aux_output_match) 2053 return 0; 2054 2055 return event->pmu->aux_output_match(aux_event); 2056 } 2057 2058 static void put_event(struct perf_event *event); 2059 static void event_sched_out(struct perf_event *event, 2060 struct perf_event_context *ctx); 2061 2062 static void perf_put_aux_event(struct perf_event *event) 2063 { 2064 struct perf_event_context *ctx = event->ctx; 2065 struct perf_event *iter; 2066 2067 /* 2068 * If event uses aux_event tear down the link 2069 */ 2070 if (event->aux_event) { 2071 iter = event->aux_event; 2072 event->aux_event = NULL; 2073 put_event(iter); 2074 return; 2075 } 2076 2077 /* 2078 * If the event is an aux_event, tear down all links to 2079 * it from other events. 2080 */ 2081 for_each_sibling_event(iter, event->group_leader) { 2082 if (iter->aux_event != event) 2083 continue; 2084 2085 iter->aux_event = NULL; 2086 put_event(event); 2087 2088 /* 2089 * If it's ACTIVE, schedule it out and put it into ERROR 2090 * state so that we don't try to schedule it again. Note 2091 * that perf_event_enable() will clear the ERROR status. 2092 */ 2093 event_sched_out(iter, ctx); 2094 perf_event_set_state(event, PERF_EVENT_STATE_ERROR); 2095 } 2096 } 2097 2098 static bool perf_need_aux_event(struct perf_event *event) 2099 { 2100 return !!event->attr.aux_output || !!event->attr.aux_sample_size; 2101 } 2102 2103 static int perf_get_aux_event(struct perf_event *event, 2104 struct perf_event *group_leader) 2105 { 2106 /* 2107 * Our group leader must be an aux event if we want to be 2108 * an aux_output. This way, the aux event will precede its 2109 * aux_output events in the group, and therefore will always 2110 * schedule first. 2111 */ 2112 if (!group_leader) 2113 return 0; 2114 2115 /* 2116 * aux_output and aux_sample_size are mutually exclusive. 2117 */ 2118 if (event->attr.aux_output && event->attr.aux_sample_size) 2119 return 0; 2120 2121 if (event->attr.aux_output && 2122 !perf_aux_output_match(event, group_leader)) 2123 return 0; 2124 2125 if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux) 2126 return 0; 2127 2128 if (!atomic_long_inc_not_zero(&group_leader->refcount)) 2129 return 0; 2130 2131 /* 2132 * Link aux_outputs to their aux event; this is undone in 2133 * perf_group_detach() by perf_put_aux_event(). When the 2134 * group in torn down, the aux_output events loose their 2135 * link to the aux_event and can't schedule any more. 2136 */ 2137 event->aux_event = group_leader; 2138 2139 return 1; 2140 } 2141 2142 static inline struct list_head *get_event_list(struct perf_event *event) 2143 { 2144 return event->attr.pinned ? &event->pmu_ctx->pinned_active : 2145 &event->pmu_ctx->flexible_active; 2146 } 2147 2148 /* 2149 * Events that have PERF_EV_CAP_SIBLING require being part of a group and 2150 * cannot exist on their own, schedule them out and move them into the ERROR 2151 * state. Also see _perf_event_enable(), it will not be able to recover 2152 * this ERROR state. 2153 */ 2154 static inline void perf_remove_sibling_event(struct perf_event *event) 2155 { 2156 event_sched_out(event, event->ctx); 2157 perf_event_set_state(event, PERF_EVENT_STATE_ERROR); 2158 } 2159 2160 static void perf_group_detach(struct perf_event *event) 2161 { 2162 struct perf_event *leader = event->group_leader; 2163 struct perf_event *sibling, *tmp; 2164 struct perf_event_context *ctx = event->ctx; 2165 2166 lockdep_assert_held(&ctx->lock); 2167 2168 /* 2169 * We can have double detach due to exit/hot-unplug + close. 2170 */ 2171 if (!(event->attach_state & PERF_ATTACH_GROUP)) 2172 return; 2173 2174 event->attach_state &= ~PERF_ATTACH_GROUP; 2175 2176 perf_put_aux_event(event); 2177 2178 /* 2179 * If this is a sibling, remove it from its group. 2180 */ 2181 if (leader != event) { 2182 list_del_init(&event->sibling_list); 2183 event->group_leader->nr_siblings--; 2184 event->group_leader->group_generation++; 2185 goto out; 2186 } 2187 2188 /* 2189 * If this was a group event with sibling events then 2190 * upgrade the siblings to singleton events by adding them 2191 * to whatever list we are on. 2192 */ 2193 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) { 2194 2195 if (sibling->event_caps & PERF_EV_CAP_SIBLING) 2196 perf_remove_sibling_event(sibling); 2197 2198 sibling->group_leader = sibling; 2199 list_del_init(&sibling->sibling_list); 2200 2201 /* Inherit group flags from the previous leader */ 2202 sibling->group_caps = event->group_caps; 2203 2204 if (sibling->attach_state & PERF_ATTACH_CONTEXT) { 2205 add_event_to_groups(sibling, event->ctx); 2206 2207 if (sibling->state == PERF_EVENT_STATE_ACTIVE) 2208 list_add_tail(&sibling->active_list, get_event_list(sibling)); 2209 } 2210 2211 WARN_ON_ONCE(sibling->ctx != event->ctx); 2212 } 2213 2214 out: 2215 for_each_sibling_event(tmp, leader) 2216 perf_event__header_size(tmp); 2217 2218 perf_event__header_size(leader); 2219 } 2220 2221 static void sync_child_event(struct perf_event *child_event); 2222 2223 static void perf_child_detach(struct perf_event *event) 2224 { 2225 struct perf_event *parent_event = event->parent; 2226 2227 if (!(event->attach_state & PERF_ATTACH_CHILD)) 2228 return; 2229 2230 event->attach_state &= ~PERF_ATTACH_CHILD; 2231 2232 if (WARN_ON_ONCE(!parent_event)) 2233 return; 2234 2235 lockdep_assert_held(&parent_event->child_mutex); 2236 2237 sync_child_event(event); 2238 list_del_init(&event->child_list); 2239 } 2240 2241 static bool is_orphaned_event(struct perf_event *event) 2242 { 2243 return event->state == PERF_EVENT_STATE_DEAD; 2244 } 2245 2246 static inline int 2247 event_filter_match(struct perf_event *event) 2248 { 2249 return (event->cpu == -1 || event->cpu == smp_processor_id()) && 2250 perf_cgroup_match(event); 2251 } 2252 2253 static void 2254 event_sched_out(struct perf_event *event, struct perf_event_context *ctx) 2255 { 2256 struct perf_event_pmu_context *epc = event->pmu_ctx; 2257 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context); 2258 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE; 2259 2260 // XXX cpc serialization, probably per-cpu IRQ disabled 2261 2262 WARN_ON_ONCE(event->ctx != ctx); 2263 lockdep_assert_held(&ctx->lock); 2264 2265 if (event->state != PERF_EVENT_STATE_ACTIVE) 2266 return; 2267 2268 /* 2269 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but 2270 * we can schedule events _OUT_ individually through things like 2271 * __perf_remove_from_context(). 2272 */ 2273 list_del_init(&event->active_list); 2274 2275 perf_pmu_disable(event->pmu); 2276 2277 event->pmu->del(event, 0); 2278 event->oncpu = -1; 2279 2280 if (event->pending_disable) { 2281 event->pending_disable = 0; 2282 perf_cgroup_event_disable(event, ctx); 2283 state = PERF_EVENT_STATE_OFF; 2284 } 2285 2286 if (event->pending_sigtrap) { 2287 bool dec = true; 2288 2289 event->pending_sigtrap = 0; 2290 if (state != PERF_EVENT_STATE_OFF && 2291 !event->pending_work) { 2292 event->pending_work = 1; 2293 dec = false; 2294 WARN_ON_ONCE(!atomic_long_inc_not_zero(&event->refcount)); 2295 task_work_add(current, &event->pending_task, TWA_RESUME); 2296 } 2297 if (dec) 2298 local_dec(&event->ctx->nr_pending); 2299 } 2300 2301 perf_event_set_state(event, state); 2302 2303 if (!is_software_event(event)) 2304 cpc->active_oncpu--; 2305 if (event->attr.freq && event->attr.sample_freq) { 2306 ctx->nr_freq--; 2307 epc->nr_freq--; 2308 } 2309 if (event->attr.exclusive || !cpc->active_oncpu) 2310 cpc->exclusive = 0; 2311 2312 perf_pmu_enable(event->pmu); 2313 } 2314 2315 static void 2316 group_sched_out(struct perf_event *group_event, struct perf_event_context *ctx) 2317 { 2318 struct perf_event *event; 2319 2320 if (group_event->state != PERF_EVENT_STATE_ACTIVE) 2321 return; 2322 2323 perf_assert_pmu_disabled(group_event->pmu_ctx->pmu); 2324 2325 event_sched_out(group_event, ctx); 2326 2327 /* 2328 * Schedule out siblings (if any): 2329 */ 2330 for_each_sibling_event(event, group_event) 2331 event_sched_out(event, ctx); 2332 } 2333 2334 #define DETACH_GROUP 0x01UL 2335 #define DETACH_CHILD 0x02UL 2336 #define DETACH_DEAD 0x04UL 2337 2338 /* 2339 * Cross CPU call to remove a performance event 2340 * 2341 * We disable the event on the hardware level first. After that we 2342 * remove it from the context list. 2343 */ 2344 static void 2345 __perf_remove_from_context(struct perf_event *event, 2346 struct perf_cpu_context *cpuctx, 2347 struct perf_event_context *ctx, 2348 void *info) 2349 { 2350 struct perf_event_pmu_context *pmu_ctx = event->pmu_ctx; 2351 unsigned long flags = (unsigned long)info; 2352 2353 if (ctx->is_active & EVENT_TIME) { 2354 update_context_time(ctx); 2355 update_cgrp_time_from_cpuctx(cpuctx, false); 2356 } 2357 2358 /* 2359 * Ensure event_sched_out() switches to OFF, at the very least 2360 * this avoids raising perf_pending_task() at this time. 2361 */ 2362 if (flags & DETACH_DEAD) 2363 event->pending_disable = 1; 2364 event_sched_out(event, ctx); 2365 if (flags & DETACH_GROUP) 2366 perf_group_detach(event); 2367 if (flags & DETACH_CHILD) 2368 perf_child_detach(event); 2369 list_del_event(event, ctx); 2370 if (flags & DETACH_DEAD) 2371 event->state = PERF_EVENT_STATE_DEAD; 2372 2373 if (!pmu_ctx->nr_events) { 2374 pmu_ctx->rotate_necessary = 0; 2375 2376 if (ctx->task && ctx->is_active) { 2377 struct perf_cpu_pmu_context *cpc; 2378 2379 cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context); 2380 WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx); 2381 cpc->task_epc = NULL; 2382 } 2383 } 2384 2385 if (!ctx->nr_events && ctx->is_active) { 2386 if (ctx == &cpuctx->ctx) 2387 update_cgrp_time_from_cpuctx(cpuctx, true); 2388 2389 ctx->is_active = 0; 2390 if (ctx->task) { 2391 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 2392 cpuctx->task_ctx = NULL; 2393 } 2394 } 2395 } 2396 2397 /* 2398 * Remove the event from a task's (or a CPU's) list of events. 2399 * 2400 * If event->ctx is a cloned context, callers must make sure that 2401 * every task struct that event->ctx->task could possibly point to 2402 * remains valid. This is OK when called from perf_release since 2403 * that only calls us on the top-level context, which can't be a clone. 2404 * When called from perf_event_exit_task, it's OK because the 2405 * context has been detached from its task. 2406 */ 2407 static void perf_remove_from_context(struct perf_event *event, unsigned long flags) 2408 { 2409 struct perf_event_context *ctx = event->ctx; 2410 2411 lockdep_assert_held(&ctx->mutex); 2412 2413 /* 2414 * Because of perf_event_exit_task(), perf_remove_from_context() ought 2415 * to work in the face of TASK_TOMBSTONE, unlike every other 2416 * event_function_call() user. 2417 */ 2418 raw_spin_lock_irq(&ctx->lock); 2419 if (!ctx->is_active) { 2420 __perf_remove_from_context(event, this_cpu_ptr(&perf_cpu_context), 2421 ctx, (void *)flags); 2422 raw_spin_unlock_irq(&ctx->lock); 2423 return; 2424 } 2425 raw_spin_unlock_irq(&ctx->lock); 2426 2427 event_function_call(event, __perf_remove_from_context, (void *)flags); 2428 } 2429 2430 /* 2431 * Cross CPU call to disable a performance event 2432 */ 2433 static void __perf_event_disable(struct perf_event *event, 2434 struct perf_cpu_context *cpuctx, 2435 struct perf_event_context *ctx, 2436 void *info) 2437 { 2438 if (event->state < PERF_EVENT_STATE_INACTIVE) 2439 return; 2440 2441 if (ctx->is_active & EVENT_TIME) { 2442 update_context_time(ctx); 2443 update_cgrp_time_from_event(event); 2444 } 2445 2446 perf_pmu_disable(event->pmu_ctx->pmu); 2447 2448 if (event == event->group_leader) 2449 group_sched_out(event, ctx); 2450 else 2451 event_sched_out(event, ctx); 2452 2453 perf_event_set_state(event, PERF_EVENT_STATE_OFF); 2454 perf_cgroup_event_disable(event, ctx); 2455 2456 perf_pmu_enable(event->pmu_ctx->pmu); 2457 } 2458 2459 /* 2460 * Disable an event. 2461 * 2462 * If event->ctx is a cloned context, callers must make sure that 2463 * every task struct that event->ctx->task could possibly point to 2464 * remains valid. This condition is satisfied when called through 2465 * perf_event_for_each_child or perf_event_for_each because they 2466 * hold the top-level event's child_mutex, so any descendant that 2467 * goes to exit will block in perf_event_exit_event(). 2468 * 2469 * When called from perf_pending_irq it's OK because event->ctx 2470 * is the current context on this CPU and preemption is disabled, 2471 * hence we can't get into perf_event_task_sched_out for this context. 2472 */ 2473 static void _perf_event_disable(struct perf_event *event) 2474 { 2475 struct perf_event_context *ctx = event->ctx; 2476 2477 raw_spin_lock_irq(&ctx->lock); 2478 if (event->state <= PERF_EVENT_STATE_OFF) { 2479 raw_spin_unlock_irq(&ctx->lock); 2480 return; 2481 } 2482 raw_spin_unlock_irq(&ctx->lock); 2483 2484 event_function_call(event, __perf_event_disable, NULL); 2485 } 2486 2487 void perf_event_disable_local(struct perf_event *event) 2488 { 2489 event_function_local(event, __perf_event_disable, NULL); 2490 } 2491 2492 /* 2493 * Strictly speaking kernel users cannot create groups and therefore this 2494 * interface does not need the perf_event_ctx_lock() magic. 2495 */ 2496 void perf_event_disable(struct perf_event *event) 2497 { 2498 struct perf_event_context *ctx; 2499 2500 ctx = perf_event_ctx_lock(event); 2501 _perf_event_disable(event); 2502 perf_event_ctx_unlock(event, ctx); 2503 } 2504 EXPORT_SYMBOL_GPL(perf_event_disable); 2505 2506 void perf_event_disable_inatomic(struct perf_event *event) 2507 { 2508 event->pending_disable = 1; 2509 irq_work_queue(&event->pending_irq); 2510 } 2511 2512 #define MAX_INTERRUPTS (~0ULL) 2513 2514 static void perf_log_throttle(struct perf_event *event, int enable); 2515 static void perf_log_itrace_start(struct perf_event *event); 2516 2517 static int 2518 event_sched_in(struct perf_event *event, struct perf_event_context *ctx) 2519 { 2520 struct perf_event_pmu_context *epc = event->pmu_ctx; 2521 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context); 2522 int ret = 0; 2523 2524 WARN_ON_ONCE(event->ctx != ctx); 2525 2526 lockdep_assert_held(&ctx->lock); 2527 2528 if (event->state <= PERF_EVENT_STATE_OFF) 2529 return 0; 2530 2531 WRITE_ONCE(event->oncpu, smp_processor_id()); 2532 /* 2533 * Order event::oncpu write to happen before the ACTIVE state is 2534 * visible. This allows perf_event_{stop,read}() to observe the correct 2535 * ->oncpu if it sees ACTIVE. 2536 */ 2537 smp_wmb(); 2538 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE); 2539 2540 /* 2541 * Unthrottle events, since we scheduled we might have missed several 2542 * ticks already, also for a heavily scheduling task there is little 2543 * guarantee it'll get a tick in a timely manner. 2544 */ 2545 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) { 2546 perf_log_throttle(event, 1); 2547 event->hw.interrupts = 0; 2548 } 2549 2550 perf_pmu_disable(event->pmu); 2551 2552 perf_log_itrace_start(event); 2553 2554 if (event->pmu->add(event, PERF_EF_START)) { 2555 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE); 2556 event->oncpu = -1; 2557 ret = -EAGAIN; 2558 goto out; 2559 } 2560 2561 if (!is_software_event(event)) 2562 cpc->active_oncpu++; 2563 if (event->attr.freq && event->attr.sample_freq) { 2564 ctx->nr_freq++; 2565 epc->nr_freq++; 2566 } 2567 if (event->attr.exclusive) 2568 cpc->exclusive = 1; 2569 2570 out: 2571 perf_pmu_enable(event->pmu); 2572 2573 return ret; 2574 } 2575 2576 static int 2577 group_sched_in(struct perf_event *group_event, struct perf_event_context *ctx) 2578 { 2579 struct perf_event *event, *partial_group = NULL; 2580 struct pmu *pmu = group_event->pmu_ctx->pmu; 2581 2582 if (group_event->state == PERF_EVENT_STATE_OFF) 2583 return 0; 2584 2585 pmu->start_txn(pmu, PERF_PMU_TXN_ADD); 2586 2587 if (event_sched_in(group_event, ctx)) 2588 goto error; 2589 2590 /* 2591 * Schedule in siblings as one group (if any): 2592 */ 2593 for_each_sibling_event(event, group_event) { 2594 if (event_sched_in(event, ctx)) { 2595 partial_group = event; 2596 goto group_error; 2597 } 2598 } 2599 2600 if (!pmu->commit_txn(pmu)) 2601 return 0; 2602 2603 group_error: 2604 /* 2605 * Groups can be scheduled in as one unit only, so undo any 2606 * partial group before returning: 2607 * The events up to the failed event are scheduled out normally. 2608 */ 2609 for_each_sibling_event(event, group_event) { 2610 if (event == partial_group) 2611 break; 2612 2613 event_sched_out(event, ctx); 2614 } 2615 event_sched_out(group_event, ctx); 2616 2617 error: 2618 pmu->cancel_txn(pmu); 2619 return -EAGAIN; 2620 } 2621 2622 /* 2623 * Work out whether we can put this event group on the CPU now. 2624 */ 2625 static int group_can_go_on(struct perf_event *event, int can_add_hw) 2626 { 2627 struct perf_event_pmu_context *epc = event->pmu_ctx; 2628 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(epc->pmu->cpu_pmu_context); 2629 2630 /* 2631 * Groups consisting entirely of software events can always go on. 2632 */ 2633 if (event->group_caps & PERF_EV_CAP_SOFTWARE) 2634 return 1; 2635 /* 2636 * If an exclusive group is already on, no other hardware 2637 * events can go on. 2638 */ 2639 if (cpc->exclusive) 2640 return 0; 2641 /* 2642 * If this group is exclusive and there are already 2643 * events on the CPU, it can't go on. 2644 */ 2645 if (event->attr.exclusive && !list_empty(get_event_list(event))) 2646 return 0; 2647 /* 2648 * Otherwise, try to add it if all previous groups were able 2649 * to go on. 2650 */ 2651 return can_add_hw; 2652 } 2653 2654 static void add_event_to_ctx(struct perf_event *event, 2655 struct perf_event_context *ctx) 2656 { 2657 list_add_event(event, ctx); 2658 perf_group_attach(event); 2659 } 2660 2661 static void task_ctx_sched_out(struct perf_event_context *ctx, 2662 enum event_type_t event_type) 2663 { 2664 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); 2665 2666 if (!cpuctx->task_ctx) 2667 return; 2668 2669 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx)) 2670 return; 2671 2672 ctx_sched_out(ctx, event_type); 2673 } 2674 2675 static void perf_event_sched_in(struct perf_cpu_context *cpuctx, 2676 struct perf_event_context *ctx) 2677 { 2678 ctx_sched_in(&cpuctx->ctx, EVENT_PINNED); 2679 if (ctx) 2680 ctx_sched_in(ctx, EVENT_PINNED); 2681 ctx_sched_in(&cpuctx->ctx, EVENT_FLEXIBLE); 2682 if (ctx) 2683 ctx_sched_in(ctx, EVENT_FLEXIBLE); 2684 } 2685 2686 /* 2687 * We want to maintain the following priority of scheduling: 2688 * - CPU pinned (EVENT_CPU | EVENT_PINNED) 2689 * - task pinned (EVENT_PINNED) 2690 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE) 2691 * - task flexible (EVENT_FLEXIBLE). 2692 * 2693 * In order to avoid unscheduling and scheduling back in everything every 2694 * time an event is added, only do it for the groups of equal priority and 2695 * below. 2696 * 2697 * This can be called after a batch operation on task events, in which case 2698 * event_type is a bit mask of the types of events involved. For CPU events, 2699 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE. 2700 */ 2701 /* 2702 * XXX: ctx_resched() reschedule entire perf_event_context while adding new 2703 * event to the context or enabling existing event in the context. We can 2704 * probably optimize it by rescheduling only affected pmu_ctx. 2705 */ 2706 static void ctx_resched(struct perf_cpu_context *cpuctx, 2707 struct perf_event_context *task_ctx, 2708 enum event_type_t event_type) 2709 { 2710 bool cpu_event = !!(event_type & EVENT_CPU); 2711 2712 /* 2713 * If pinned groups are involved, flexible groups also need to be 2714 * scheduled out. 2715 */ 2716 if (event_type & EVENT_PINNED) 2717 event_type |= EVENT_FLEXIBLE; 2718 2719 event_type &= EVENT_ALL; 2720 2721 perf_ctx_disable(&cpuctx->ctx, false); 2722 if (task_ctx) { 2723 perf_ctx_disable(task_ctx, false); 2724 task_ctx_sched_out(task_ctx, event_type); 2725 } 2726 2727 /* 2728 * Decide which cpu ctx groups to schedule out based on the types 2729 * of events that caused rescheduling: 2730 * - EVENT_CPU: schedule out corresponding groups; 2731 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups; 2732 * - otherwise, do nothing more. 2733 */ 2734 if (cpu_event) 2735 ctx_sched_out(&cpuctx->ctx, event_type); 2736 else if (event_type & EVENT_PINNED) 2737 ctx_sched_out(&cpuctx->ctx, EVENT_FLEXIBLE); 2738 2739 perf_event_sched_in(cpuctx, task_ctx); 2740 2741 perf_ctx_enable(&cpuctx->ctx, false); 2742 if (task_ctx) 2743 perf_ctx_enable(task_ctx, false); 2744 } 2745 2746 void perf_pmu_resched(struct pmu *pmu) 2747 { 2748 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); 2749 struct perf_event_context *task_ctx = cpuctx->task_ctx; 2750 2751 perf_ctx_lock(cpuctx, task_ctx); 2752 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU); 2753 perf_ctx_unlock(cpuctx, task_ctx); 2754 } 2755 2756 /* 2757 * Cross CPU call to install and enable a performance event 2758 * 2759 * Very similar to remote_function() + event_function() but cannot assume that 2760 * things like ctx->is_active and cpuctx->task_ctx are set. 2761 */ 2762 static int __perf_install_in_context(void *info) 2763 { 2764 struct perf_event *event = info; 2765 struct perf_event_context *ctx = event->ctx; 2766 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); 2767 struct perf_event_context *task_ctx = cpuctx->task_ctx; 2768 bool reprogram = true; 2769 int ret = 0; 2770 2771 raw_spin_lock(&cpuctx->ctx.lock); 2772 if (ctx->task) { 2773 raw_spin_lock(&ctx->lock); 2774 task_ctx = ctx; 2775 2776 reprogram = (ctx->task == current); 2777 2778 /* 2779 * If the task is running, it must be running on this CPU, 2780 * otherwise we cannot reprogram things. 2781 * 2782 * If its not running, we don't care, ctx->lock will 2783 * serialize against it becoming runnable. 2784 */ 2785 if (task_curr(ctx->task) && !reprogram) { 2786 ret = -ESRCH; 2787 goto unlock; 2788 } 2789 2790 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx); 2791 } else if (task_ctx) { 2792 raw_spin_lock(&task_ctx->lock); 2793 } 2794 2795 #ifdef CONFIG_CGROUP_PERF 2796 if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) { 2797 /* 2798 * If the current cgroup doesn't match the event's 2799 * cgroup, we should not try to schedule it. 2800 */ 2801 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx); 2802 reprogram = cgroup_is_descendant(cgrp->css.cgroup, 2803 event->cgrp->css.cgroup); 2804 } 2805 #endif 2806 2807 if (reprogram) { 2808 ctx_sched_out(ctx, EVENT_TIME); 2809 add_event_to_ctx(event, ctx); 2810 ctx_resched(cpuctx, task_ctx, get_event_type(event)); 2811 } else { 2812 add_event_to_ctx(event, ctx); 2813 } 2814 2815 unlock: 2816 perf_ctx_unlock(cpuctx, task_ctx); 2817 2818 return ret; 2819 } 2820 2821 static bool exclusive_event_installable(struct perf_event *event, 2822 struct perf_event_context *ctx); 2823 2824 /* 2825 * Attach a performance event to a context. 2826 * 2827 * Very similar to event_function_call, see comment there. 2828 */ 2829 static void 2830 perf_install_in_context(struct perf_event_context *ctx, 2831 struct perf_event *event, 2832 int cpu) 2833 { 2834 struct task_struct *task = READ_ONCE(ctx->task); 2835 2836 lockdep_assert_held(&ctx->mutex); 2837 2838 WARN_ON_ONCE(!exclusive_event_installable(event, ctx)); 2839 2840 if (event->cpu != -1) 2841 WARN_ON_ONCE(event->cpu != cpu); 2842 2843 /* 2844 * Ensures that if we can observe event->ctx, both the event and ctx 2845 * will be 'complete'. See perf_iterate_sb_cpu(). 2846 */ 2847 smp_store_release(&event->ctx, ctx); 2848 2849 /* 2850 * perf_event_attr::disabled events will not run and can be initialized 2851 * without IPI. Except when this is the first event for the context, in 2852 * that case we need the magic of the IPI to set ctx->is_active. 2853 * 2854 * The IOC_ENABLE that is sure to follow the creation of a disabled 2855 * event will issue the IPI and reprogram the hardware. 2856 */ 2857 if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF && 2858 ctx->nr_events && !is_cgroup_event(event)) { 2859 raw_spin_lock_irq(&ctx->lock); 2860 if (ctx->task == TASK_TOMBSTONE) { 2861 raw_spin_unlock_irq(&ctx->lock); 2862 return; 2863 } 2864 add_event_to_ctx(event, ctx); 2865 raw_spin_unlock_irq(&ctx->lock); 2866 return; 2867 } 2868 2869 if (!task) { 2870 cpu_function_call(cpu, __perf_install_in_context, event); 2871 return; 2872 } 2873 2874 /* 2875 * Should not happen, we validate the ctx is still alive before calling. 2876 */ 2877 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) 2878 return; 2879 2880 /* 2881 * Installing events is tricky because we cannot rely on ctx->is_active 2882 * to be set in case this is the nr_events 0 -> 1 transition. 2883 * 2884 * Instead we use task_curr(), which tells us if the task is running. 2885 * However, since we use task_curr() outside of rq::lock, we can race 2886 * against the actual state. This means the result can be wrong. 2887 * 2888 * If we get a false positive, we retry, this is harmless. 2889 * 2890 * If we get a false negative, things are complicated. If we are after 2891 * perf_event_context_sched_in() ctx::lock will serialize us, and the 2892 * value must be correct. If we're before, it doesn't matter since 2893 * perf_event_context_sched_in() will program the counter. 2894 * 2895 * However, this hinges on the remote context switch having observed 2896 * our task->perf_event_ctxp[] store, such that it will in fact take 2897 * ctx::lock in perf_event_context_sched_in(). 2898 * 2899 * We do this by task_function_call(), if the IPI fails to hit the task 2900 * we know any future context switch of task must see the 2901 * perf_event_ctpx[] store. 2902 */ 2903 2904 /* 2905 * This smp_mb() orders the task->perf_event_ctxp[] store with the 2906 * task_cpu() load, such that if the IPI then does not find the task 2907 * running, a future context switch of that task must observe the 2908 * store. 2909 */ 2910 smp_mb(); 2911 again: 2912 if (!task_function_call(task, __perf_install_in_context, event)) 2913 return; 2914 2915 raw_spin_lock_irq(&ctx->lock); 2916 task = ctx->task; 2917 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) { 2918 /* 2919 * Cannot happen because we already checked above (which also 2920 * cannot happen), and we hold ctx->mutex, which serializes us 2921 * against perf_event_exit_task_context(). 2922 */ 2923 raw_spin_unlock_irq(&ctx->lock); 2924 return; 2925 } 2926 /* 2927 * If the task is not running, ctx->lock will avoid it becoming so, 2928 * thus we can safely install the event. 2929 */ 2930 if (task_curr(task)) { 2931 raw_spin_unlock_irq(&ctx->lock); 2932 goto again; 2933 } 2934 add_event_to_ctx(event, ctx); 2935 raw_spin_unlock_irq(&ctx->lock); 2936 } 2937 2938 /* 2939 * Cross CPU call to enable a performance event 2940 */ 2941 static void __perf_event_enable(struct perf_event *event, 2942 struct perf_cpu_context *cpuctx, 2943 struct perf_event_context *ctx, 2944 void *info) 2945 { 2946 struct perf_event *leader = event->group_leader; 2947 struct perf_event_context *task_ctx; 2948 2949 if (event->state >= PERF_EVENT_STATE_INACTIVE || 2950 event->state <= PERF_EVENT_STATE_ERROR) 2951 return; 2952 2953 if (ctx->is_active) 2954 ctx_sched_out(ctx, EVENT_TIME); 2955 2956 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE); 2957 perf_cgroup_event_enable(event, ctx); 2958 2959 if (!ctx->is_active) 2960 return; 2961 2962 if (!event_filter_match(event)) { 2963 ctx_sched_in(ctx, EVENT_TIME); 2964 return; 2965 } 2966 2967 /* 2968 * If the event is in a group and isn't the group leader, 2969 * then don't put it on unless the group is on. 2970 */ 2971 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) { 2972 ctx_sched_in(ctx, EVENT_TIME); 2973 return; 2974 } 2975 2976 task_ctx = cpuctx->task_ctx; 2977 if (ctx->task) 2978 WARN_ON_ONCE(task_ctx != ctx); 2979 2980 ctx_resched(cpuctx, task_ctx, get_event_type(event)); 2981 } 2982 2983 /* 2984 * Enable an event. 2985 * 2986 * If event->ctx is a cloned context, callers must make sure that 2987 * every task struct that event->ctx->task could possibly point to 2988 * remains valid. This condition is satisfied when called through 2989 * perf_event_for_each_child or perf_event_for_each as described 2990 * for perf_event_disable. 2991 */ 2992 static void _perf_event_enable(struct perf_event *event) 2993 { 2994 struct perf_event_context *ctx = event->ctx; 2995 2996 raw_spin_lock_irq(&ctx->lock); 2997 if (event->state >= PERF_EVENT_STATE_INACTIVE || 2998 event->state < PERF_EVENT_STATE_ERROR) { 2999 out: 3000 raw_spin_unlock_irq(&ctx->lock); 3001 return; 3002 } 3003 3004 /* 3005 * If the event is in error state, clear that first. 3006 * 3007 * That way, if we see the event in error state below, we know that it 3008 * has gone back into error state, as distinct from the task having 3009 * been scheduled away before the cross-call arrived. 3010 */ 3011 if (event->state == PERF_EVENT_STATE_ERROR) { 3012 /* 3013 * Detached SIBLING events cannot leave ERROR state. 3014 */ 3015 if (event->event_caps & PERF_EV_CAP_SIBLING && 3016 event->group_leader == event) 3017 goto out; 3018 3019 event->state = PERF_EVENT_STATE_OFF; 3020 } 3021 raw_spin_unlock_irq(&ctx->lock); 3022 3023 event_function_call(event, __perf_event_enable, NULL); 3024 } 3025 3026 /* 3027 * See perf_event_disable(); 3028 */ 3029 void perf_event_enable(struct perf_event *event) 3030 { 3031 struct perf_event_context *ctx; 3032 3033 ctx = perf_event_ctx_lock(event); 3034 _perf_event_enable(event); 3035 perf_event_ctx_unlock(event, ctx); 3036 } 3037 EXPORT_SYMBOL_GPL(perf_event_enable); 3038 3039 struct stop_event_data { 3040 struct perf_event *event; 3041 unsigned int restart; 3042 }; 3043 3044 static int __perf_event_stop(void *info) 3045 { 3046 struct stop_event_data *sd = info; 3047 struct perf_event *event = sd->event; 3048 3049 /* if it's already INACTIVE, do nothing */ 3050 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) 3051 return 0; 3052 3053 /* matches smp_wmb() in event_sched_in() */ 3054 smp_rmb(); 3055 3056 /* 3057 * There is a window with interrupts enabled before we get here, 3058 * so we need to check again lest we try to stop another CPU's event. 3059 */ 3060 if (READ_ONCE(event->oncpu) != smp_processor_id()) 3061 return -EAGAIN; 3062 3063 event->pmu->stop(event, PERF_EF_UPDATE); 3064 3065 /* 3066 * May race with the actual stop (through perf_pmu_output_stop()), 3067 * but it is only used for events with AUX ring buffer, and such 3068 * events will refuse to restart because of rb::aux_mmap_count==0, 3069 * see comments in perf_aux_output_begin(). 3070 * 3071 * Since this is happening on an event-local CPU, no trace is lost 3072 * while restarting. 3073 */ 3074 if (sd->restart) 3075 event->pmu->start(event, 0); 3076 3077 return 0; 3078 } 3079 3080 static int perf_event_stop(struct perf_event *event, int restart) 3081 { 3082 struct stop_event_data sd = { 3083 .event = event, 3084 .restart = restart, 3085 }; 3086 int ret = 0; 3087 3088 do { 3089 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) 3090 return 0; 3091 3092 /* matches smp_wmb() in event_sched_in() */ 3093 smp_rmb(); 3094 3095 /* 3096 * We only want to restart ACTIVE events, so if the event goes 3097 * inactive here (event->oncpu==-1), there's nothing more to do; 3098 * fall through with ret==-ENXIO. 3099 */ 3100 ret = cpu_function_call(READ_ONCE(event->oncpu), 3101 __perf_event_stop, &sd); 3102 } while (ret == -EAGAIN); 3103 3104 return ret; 3105 } 3106 3107 /* 3108 * In order to contain the amount of racy and tricky in the address filter 3109 * configuration management, it is a two part process: 3110 * 3111 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below, 3112 * we update the addresses of corresponding vmas in 3113 * event::addr_filter_ranges array and bump the event::addr_filters_gen; 3114 * (p2) when an event is scheduled in (pmu::add), it calls 3115 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync() 3116 * if the generation has changed since the previous call. 3117 * 3118 * If (p1) happens while the event is active, we restart it to force (p2). 3119 * 3120 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on 3121 * pre-existing mappings, called once when new filters arrive via SET_FILTER 3122 * ioctl; 3123 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly 3124 * registered mapping, called for every new mmap(), with mm::mmap_lock down 3125 * for reading; 3126 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process 3127 * of exec. 3128 */ 3129 void perf_event_addr_filters_sync(struct perf_event *event) 3130 { 3131 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 3132 3133 if (!has_addr_filter(event)) 3134 return; 3135 3136 raw_spin_lock(&ifh->lock); 3137 if (event->addr_filters_gen != event->hw.addr_filters_gen) { 3138 event->pmu->addr_filters_sync(event); 3139 event->hw.addr_filters_gen = event->addr_filters_gen; 3140 } 3141 raw_spin_unlock(&ifh->lock); 3142 } 3143 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync); 3144 3145 static int _perf_event_refresh(struct perf_event *event, int refresh) 3146 { 3147 /* 3148 * not supported on inherited events 3149 */ 3150 if (event->attr.inherit || !is_sampling_event(event)) 3151 return -EINVAL; 3152 3153 atomic_add(refresh, &event->event_limit); 3154 _perf_event_enable(event); 3155 3156 return 0; 3157 } 3158 3159 /* 3160 * See perf_event_disable() 3161 */ 3162 int perf_event_refresh(struct perf_event *event, int refresh) 3163 { 3164 struct perf_event_context *ctx; 3165 int ret; 3166 3167 ctx = perf_event_ctx_lock(event); 3168 ret = _perf_event_refresh(event, refresh); 3169 perf_event_ctx_unlock(event, ctx); 3170 3171 return ret; 3172 } 3173 EXPORT_SYMBOL_GPL(perf_event_refresh); 3174 3175 static int perf_event_modify_breakpoint(struct perf_event *bp, 3176 struct perf_event_attr *attr) 3177 { 3178 int err; 3179 3180 _perf_event_disable(bp); 3181 3182 err = modify_user_hw_breakpoint_check(bp, attr, true); 3183 3184 if (!bp->attr.disabled) 3185 _perf_event_enable(bp); 3186 3187 return err; 3188 } 3189 3190 /* 3191 * Copy event-type-independent attributes that may be modified. 3192 */ 3193 static void perf_event_modify_copy_attr(struct perf_event_attr *to, 3194 const struct perf_event_attr *from) 3195 { 3196 to->sig_data = from->sig_data; 3197 } 3198 3199 static int perf_event_modify_attr(struct perf_event *event, 3200 struct perf_event_attr *attr) 3201 { 3202 int (*func)(struct perf_event *, struct perf_event_attr *); 3203 struct perf_event *child; 3204 int err; 3205 3206 if (event->attr.type != attr->type) 3207 return -EINVAL; 3208 3209 switch (event->attr.type) { 3210 case PERF_TYPE_BREAKPOINT: 3211 func = perf_event_modify_breakpoint; 3212 break; 3213 default: 3214 /* Place holder for future additions. */ 3215 return -EOPNOTSUPP; 3216 } 3217 3218 WARN_ON_ONCE(event->ctx->parent_ctx); 3219 3220 mutex_lock(&event->child_mutex); 3221 /* 3222 * Event-type-independent attributes must be copied before event-type 3223 * modification, which will validate that final attributes match the 3224 * source attributes after all relevant attributes have been copied. 3225 */ 3226 perf_event_modify_copy_attr(&event->attr, attr); 3227 err = func(event, attr); 3228 if (err) 3229 goto out; 3230 list_for_each_entry(child, &event->child_list, child_list) { 3231 perf_event_modify_copy_attr(&child->attr, attr); 3232 err = func(child, attr); 3233 if (err) 3234 goto out; 3235 } 3236 out: 3237 mutex_unlock(&event->child_mutex); 3238 return err; 3239 } 3240 3241 static void __pmu_ctx_sched_out(struct perf_event_pmu_context *pmu_ctx, 3242 enum event_type_t event_type) 3243 { 3244 struct perf_event_context *ctx = pmu_ctx->ctx; 3245 struct perf_event *event, *tmp; 3246 struct pmu *pmu = pmu_ctx->pmu; 3247 3248 if (ctx->task && !ctx->is_active) { 3249 struct perf_cpu_pmu_context *cpc; 3250 3251 cpc = this_cpu_ptr(pmu->cpu_pmu_context); 3252 WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx); 3253 cpc->task_epc = NULL; 3254 } 3255 3256 if (!event_type) 3257 return; 3258 3259 perf_pmu_disable(pmu); 3260 if (event_type & EVENT_PINNED) { 3261 list_for_each_entry_safe(event, tmp, 3262 &pmu_ctx->pinned_active, 3263 active_list) 3264 group_sched_out(event, ctx); 3265 } 3266 3267 if (event_type & EVENT_FLEXIBLE) { 3268 list_for_each_entry_safe(event, tmp, 3269 &pmu_ctx->flexible_active, 3270 active_list) 3271 group_sched_out(event, ctx); 3272 /* 3273 * Since we cleared EVENT_FLEXIBLE, also clear 3274 * rotate_necessary, is will be reset by 3275 * ctx_flexible_sched_in() when needed. 3276 */ 3277 pmu_ctx->rotate_necessary = 0; 3278 } 3279 perf_pmu_enable(pmu); 3280 } 3281 3282 static void 3283 ctx_sched_out(struct perf_event_context *ctx, enum event_type_t event_type) 3284 { 3285 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); 3286 struct perf_event_pmu_context *pmu_ctx; 3287 int is_active = ctx->is_active; 3288 bool cgroup = event_type & EVENT_CGROUP; 3289 3290 event_type &= ~EVENT_CGROUP; 3291 3292 lockdep_assert_held(&ctx->lock); 3293 3294 if (likely(!ctx->nr_events)) { 3295 /* 3296 * See __perf_remove_from_context(). 3297 */ 3298 WARN_ON_ONCE(ctx->is_active); 3299 if (ctx->task) 3300 WARN_ON_ONCE(cpuctx->task_ctx); 3301 return; 3302 } 3303 3304 /* 3305 * Always update time if it was set; not only when it changes. 3306 * Otherwise we can 'forget' to update time for any but the last 3307 * context we sched out. For example: 3308 * 3309 * ctx_sched_out(.event_type = EVENT_FLEXIBLE) 3310 * ctx_sched_out(.event_type = EVENT_PINNED) 3311 * 3312 * would only update time for the pinned events. 3313 */ 3314 if (is_active & EVENT_TIME) { 3315 /* update (and stop) ctx time */ 3316 update_context_time(ctx); 3317 update_cgrp_time_from_cpuctx(cpuctx, ctx == &cpuctx->ctx); 3318 /* 3319 * CPU-release for the below ->is_active store, 3320 * see __load_acquire() in perf_event_time_now() 3321 */ 3322 barrier(); 3323 } 3324 3325 ctx->is_active &= ~event_type; 3326 if (!(ctx->is_active & EVENT_ALL)) 3327 ctx->is_active = 0; 3328 3329 if (ctx->task) { 3330 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 3331 if (!ctx->is_active) 3332 cpuctx->task_ctx = NULL; 3333 } 3334 3335 is_active ^= ctx->is_active; /* changed bits */ 3336 3337 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) { 3338 if (cgroup && !pmu_ctx->nr_cgroups) 3339 continue; 3340 __pmu_ctx_sched_out(pmu_ctx, is_active); 3341 } 3342 } 3343 3344 /* 3345 * Test whether two contexts are equivalent, i.e. whether they have both been 3346 * cloned from the same version of the same context. 3347 * 3348 * Equivalence is measured using a generation number in the context that is 3349 * incremented on each modification to it; see unclone_ctx(), list_add_event() 3350 * and list_del_event(). 3351 */ 3352 static int context_equiv(struct perf_event_context *ctx1, 3353 struct perf_event_context *ctx2) 3354 { 3355 lockdep_assert_held(&ctx1->lock); 3356 lockdep_assert_held(&ctx2->lock); 3357 3358 /* Pinning disables the swap optimization */ 3359 if (ctx1->pin_count || ctx2->pin_count) 3360 return 0; 3361 3362 /* If ctx1 is the parent of ctx2 */ 3363 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen) 3364 return 1; 3365 3366 /* If ctx2 is the parent of ctx1 */ 3367 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation) 3368 return 1; 3369 3370 /* 3371 * If ctx1 and ctx2 have the same parent; we flatten the parent 3372 * hierarchy, see perf_event_init_context(). 3373 */ 3374 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx && 3375 ctx1->parent_gen == ctx2->parent_gen) 3376 return 1; 3377 3378 /* Unmatched */ 3379 return 0; 3380 } 3381 3382 static void __perf_event_sync_stat(struct perf_event *event, 3383 struct perf_event *next_event) 3384 { 3385 u64 value; 3386 3387 if (!event->attr.inherit_stat) 3388 return; 3389 3390 /* 3391 * Update the event value, we cannot use perf_event_read() 3392 * because we're in the middle of a context switch and have IRQs 3393 * disabled, which upsets smp_call_function_single(), however 3394 * we know the event must be on the current CPU, therefore we 3395 * don't need to use it. 3396 */ 3397 if (event->state == PERF_EVENT_STATE_ACTIVE) 3398 event->pmu->read(event); 3399 3400 perf_event_update_time(event); 3401 3402 /* 3403 * In order to keep per-task stats reliable we need to flip the event 3404 * values when we flip the contexts. 3405 */ 3406 value = local64_read(&next_event->count); 3407 value = local64_xchg(&event->count, value); 3408 local64_set(&next_event->count, value); 3409 3410 swap(event->total_time_enabled, next_event->total_time_enabled); 3411 swap(event->total_time_running, next_event->total_time_running); 3412 3413 /* 3414 * Since we swizzled the values, update the user visible data too. 3415 */ 3416 perf_event_update_userpage(event); 3417 perf_event_update_userpage(next_event); 3418 } 3419 3420 static void perf_event_sync_stat(struct perf_event_context *ctx, 3421 struct perf_event_context *next_ctx) 3422 { 3423 struct perf_event *event, *next_event; 3424 3425 if (!ctx->nr_stat) 3426 return; 3427 3428 update_context_time(ctx); 3429 3430 event = list_first_entry(&ctx->event_list, 3431 struct perf_event, event_entry); 3432 3433 next_event = list_first_entry(&next_ctx->event_list, 3434 struct perf_event, event_entry); 3435 3436 while (&event->event_entry != &ctx->event_list && 3437 &next_event->event_entry != &next_ctx->event_list) { 3438 3439 __perf_event_sync_stat(event, next_event); 3440 3441 event = list_next_entry(event, event_entry); 3442 next_event = list_next_entry(next_event, event_entry); 3443 } 3444 } 3445 3446 #define double_list_for_each_entry(pos1, pos2, head1, head2, member) \ 3447 for (pos1 = list_first_entry(head1, typeof(*pos1), member), \ 3448 pos2 = list_first_entry(head2, typeof(*pos2), member); \ 3449 !list_entry_is_head(pos1, head1, member) && \ 3450 !list_entry_is_head(pos2, head2, member); \ 3451 pos1 = list_next_entry(pos1, member), \ 3452 pos2 = list_next_entry(pos2, member)) 3453 3454 static void perf_event_swap_task_ctx_data(struct perf_event_context *prev_ctx, 3455 struct perf_event_context *next_ctx) 3456 { 3457 struct perf_event_pmu_context *prev_epc, *next_epc; 3458 3459 if (!prev_ctx->nr_task_data) 3460 return; 3461 3462 double_list_for_each_entry(prev_epc, next_epc, 3463 &prev_ctx->pmu_ctx_list, &next_ctx->pmu_ctx_list, 3464 pmu_ctx_entry) { 3465 3466 if (WARN_ON_ONCE(prev_epc->pmu != next_epc->pmu)) 3467 continue; 3468 3469 /* 3470 * PMU specific parts of task perf context can require 3471 * additional synchronization. As an example of such 3472 * synchronization see implementation details of Intel 3473 * LBR call stack data profiling; 3474 */ 3475 if (prev_epc->pmu->swap_task_ctx) 3476 prev_epc->pmu->swap_task_ctx(prev_epc, next_epc); 3477 else 3478 swap(prev_epc->task_ctx_data, next_epc->task_ctx_data); 3479 } 3480 } 3481 3482 static void perf_ctx_sched_task_cb(struct perf_event_context *ctx, bool sched_in) 3483 { 3484 struct perf_event_pmu_context *pmu_ctx; 3485 struct perf_cpu_pmu_context *cpc; 3486 3487 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) { 3488 cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context); 3489 3490 if (cpc->sched_cb_usage && pmu_ctx->pmu->sched_task) 3491 pmu_ctx->pmu->sched_task(pmu_ctx, sched_in); 3492 } 3493 } 3494 3495 static void 3496 perf_event_context_sched_out(struct task_struct *task, struct task_struct *next) 3497 { 3498 struct perf_event_context *ctx = task->perf_event_ctxp; 3499 struct perf_event_context *next_ctx; 3500 struct perf_event_context *parent, *next_parent; 3501 int do_switch = 1; 3502 3503 if (likely(!ctx)) 3504 return; 3505 3506 rcu_read_lock(); 3507 next_ctx = rcu_dereference(next->perf_event_ctxp); 3508 if (!next_ctx) 3509 goto unlock; 3510 3511 parent = rcu_dereference(ctx->parent_ctx); 3512 next_parent = rcu_dereference(next_ctx->parent_ctx); 3513 3514 /* If neither context have a parent context; they cannot be clones. */ 3515 if (!parent && !next_parent) 3516 goto unlock; 3517 3518 if (next_parent == ctx || next_ctx == parent || next_parent == parent) { 3519 /* 3520 * Looks like the two contexts are clones, so we might be 3521 * able to optimize the context switch. We lock both 3522 * contexts and check that they are clones under the 3523 * lock (including re-checking that neither has been 3524 * uncloned in the meantime). It doesn't matter which 3525 * order we take the locks because no other cpu could 3526 * be trying to lock both of these tasks. 3527 */ 3528 raw_spin_lock(&ctx->lock); 3529 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING); 3530 if (context_equiv(ctx, next_ctx)) { 3531 3532 perf_ctx_disable(ctx, false); 3533 3534 /* PMIs are disabled; ctx->nr_pending is stable. */ 3535 if (local_read(&ctx->nr_pending) || 3536 local_read(&next_ctx->nr_pending)) { 3537 /* 3538 * Must not swap out ctx when there's pending 3539 * events that rely on the ctx->task relation. 3540 */ 3541 raw_spin_unlock(&next_ctx->lock); 3542 rcu_read_unlock(); 3543 goto inside_switch; 3544 } 3545 3546 WRITE_ONCE(ctx->task, next); 3547 WRITE_ONCE(next_ctx->task, task); 3548 3549 perf_ctx_sched_task_cb(ctx, false); 3550 perf_event_swap_task_ctx_data(ctx, next_ctx); 3551 3552 perf_ctx_enable(ctx, false); 3553 3554 /* 3555 * RCU_INIT_POINTER here is safe because we've not 3556 * modified the ctx and the above modification of 3557 * ctx->task and ctx->task_ctx_data are immaterial 3558 * since those values are always verified under 3559 * ctx->lock which we're now holding. 3560 */ 3561 RCU_INIT_POINTER(task->perf_event_ctxp, next_ctx); 3562 RCU_INIT_POINTER(next->perf_event_ctxp, ctx); 3563 3564 do_switch = 0; 3565 3566 perf_event_sync_stat(ctx, next_ctx); 3567 } 3568 raw_spin_unlock(&next_ctx->lock); 3569 raw_spin_unlock(&ctx->lock); 3570 } 3571 unlock: 3572 rcu_read_unlock(); 3573 3574 if (do_switch) { 3575 raw_spin_lock(&ctx->lock); 3576 perf_ctx_disable(ctx, false); 3577 3578 inside_switch: 3579 perf_ctx_sched_task_cb(ctx, false); 3580 task_ctx_sched_out(ctx, EVENT_ALL); 3581 3582 perf_ctx_enable(ctx, false); 3583 raw_spin_unlock(&ctx->lock); 3584 } 3585 } 3586 3587 static DEFINE_PER_CPU(struct list_head, sched_cb_list); 3588 static DEFINE_PER_CPU(int, perf_sched_cb_usages); 3589 3590 void perf_sched_cb_dec(struct pmu *pmu) 3591 { 3592 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(pmu->cpu_pmu_context); 3593 3594 this_cpu_dec(perf_sched_cb_usages); 3595 barrier(); 3596 3597 if (!--cpc->sched_cb_usage) 3598 list_del(&cpc->sched_cb_entry); 3599 } 3600 3601 3602 void perf_sched_cb_inc(struct pmu *pmu) 3603 { 3604 struct perf_cpu_pmu_context *cpc = this_cpu_ptr(pmu->cpu_pmu_context); 3605 3606 if (!cpc->sched_cb_usage++) 3607 list_add(&cpc->sched_cb_entry, this_cpu_ptr(&sched_cb_list)); 3608 3609 barrier(); 3610 this_cpu_inc(perf_sched_cb_usages); 3611 } 3612 3613 /* 3614 * This function provides the context switch callback to the lower code 3615 * layer. It is invoked ONLY when the context switch callback is enabled. 3616 * 3617 * This callback is relevant even to per-cpu events; for example multi event 3618 * PEBS requires this to provide PID/TID information. This requires we flush 3619 * all queued PEBS records before we context switch to a new task. 3620 */ 3621 static void __perf_pmu_sched_task(struct perf_cpu_pmu_context *cpc, bool sched_in) 3622 { 3623 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); 3624 struct pmu *pmu; 3625 3626 pmu = cpc->epc.pmu; 3627 3628 /* software PMUs will not have sched_task */ 3629 if (WARN_ON_ONCE(!pmu->sched_task)) 3630 return; 3631 3632 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 3633 perf_pmu_disable(pmu); 3634 3635 pmu->sched_task(cpc->task_epc, sched_in); 3636 3637 perf_pmu_enable(pmu); 3638 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 3639 } 3640 3641 static void perf_pmu_sched_task(struct task_struct *prev, 3642 struct task_struct *next, 3643 bool sched_in) 3644 { 3645 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); 3646 struct perf_cpu_pmu_context *cpc; 3647 3648 /* cpuctx->task_ctx will be handled in perf_event_context_sched_in/out */ 3649 if (prev == next || cpuctx->task_ctx) 3650 return; 3651 3652 list_for_each_entry(cpc, this_cpu_ptr(&sched_cb_list), sched_cb_entry) 3653 __perf_pmu_sched_task(cpc, sched_in); 3654 } 3655 3656 static void perf_event_switch(struct task_struct *task, 3657 struct task_struct *next_prev, bool sched_in); 3658 3659 /* 3660 * Called from scheduler to remove the events of the current task, 3661 * with interrupts disabled. 3662 * 3663 * We stop each event and update the event value in event->count. 3664 * 3665 * This does not protect us against NMI, but disable() 3666 * sets the disabled bit in the control field of event _before_ 3667 * accessing the event control register. If a NMI hits, then it will 3668 * not restart the event. 3669 */ 3670 void __perf_event_task_sched_out(struct task_struct *task, 3671 struct task_struct *next) 3672 { 3673 if (__this_cpu_read(perf_sched_cb_usages)) 3674 perf_pmu_sched_task(task, next, false); 3675 3676 if (atomic_read(&nr_switch_events)) 3677 perf_event_switch(task, next, false); 3678 3679 perf_event_context_sched_out(task, next); 3680 3681 /* 3682 * if cgroup events exist on this CPU, then we need 3683 * to check if we have to switch out PMU state. 3684 * cgroup event are system-wide mode only 3685 */ 3686 perf_cgroup_switch(next); 3687 } 3688 3689 static bool perf_less_group_idx(const void *l, const void *r) 3690 { 3691 const struct perf_event *le = *(const struct perf_event **)l; 3692 const struct perf_event *re = *(const struct perf_event **)r; 3693 3694 return le->group_index < re->group_index; 3695 } 3696 3697 static void swap_ptr(void *l, void *r) 3698 { 3699 void **lp = l, **rp = r; 3700 3701 swap(*lp, *rp); 3702 } 3703 3704 static const struct min_heap_callbacks perf_min_heap = { 3705 .elem_size = sizeof(struct perf_event *), 3706 .less = perf_less_group_idx, 3707 .swp = swap_ptr, 3708 }; 3709 3710 static void __heap_add(struct min_heap *heap, struct perf_event *event) 3711 { 3712 struct perf_event **itrs = heap->data; 3713 3714 if (event) { 3715 itrs[heap->nr] = event; 3716 heap->nr++; 3717 } 3718 } 3719 3720 static void __link_epc(struct perf_event_pmu_context *pmu_ctx) 3721 { 3722 struct perf_cpu_pmu_context *cpc; 3723 3724 if (!pmu_ctx->ctx->task) 3725 return; 3726 3727 cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context); 3728 WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx); 3729 cpc->task_epc = pmu_ctx; 3730 } 3731 3732 static noinline int visit_groups_merge(struct perf_event_context *ctx, 3733 struct perf_event_groups *groups, int cpu, 3734 struct pmu *pmu, 3735 int (*func)(struct perf_event *, void *), 3736 void *data) 3737 { 3738 #ifdef CONFIG_CGROUP_PERF 3739 struct cgroup_subsys_state *css = NULL; 3740 #endif 3741 struct perf_cpu_context *cpuctx = NULL; 3742 /* Space for per CPU and/or any CPU event iterators. */ 3743 struct perf_event *itrs[2]; 3744 struct min_heap event_heap; 3745 struct perf_event **evt; 3746 int ret; 3747 3748 if (pmu->filter && pmu->filter(pmu, cpu)) 3749 return 0; 3750 3751 if (!ctx->task) { 3752 cpuctx = this_cpu_ptr(&perf_cpu_context); 3753 event_heap = (struct min_heap){ 3754 .data = cpuctx->heap, 3755 .nr = 0, 3756 .size = cpuctx->heap_size, 3757 }; 3758 3759 lockdep_assert_held(&cpuctx->ctx.lock); 3760 3761 #ifdef CONFIG_CGROUP_PERF 3762 if (cpuctx->cgrp) 3763 css = &cpuctx->cgrp->css; 3764 #endif 3765 } else { 3766 event_heap = (struct min_heap){ 3767 .data = itrs, 3768 .nr = 0, 3769 .size = ARRAY_SIZE(itrs), 3770 }; 3771 /* Events not within a CPU context may be on any CPU. */ 3772 __heap_add(&event_heap, perf_event_groups_first(groups, -1, pmu, NULL)); 3773 } 3774 evt = event_heap.data; 3775 3776 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, pmu, NULL)); 3777 3778 #ifdef CONFIG_CGROUP_PERF 3779 for (; css; css = css->parent) 3780 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, pmu, css->cgroup)); 3781 #endif 3782 3783 if (event_heap.nr) { 3784 __link_epc((*evt)->pmu_ctx); 3785 perf_assert_pmu_disabled((*evt)->pmu_ctx->pmu); 3786 } 3787 3788 min_heapify_all(&event_heap, &perf_min_heap); 3789 3790 while (event_heap.nr) { 3791 ret = func(*evt, data); 3792 if (ret) 3793 return ret; 3794 3795 *evt = perf_event_groups_next(*evt, pmu); 3796 if (*evt) 3797 min_heapify(&event_heap, 0, &perf_min_heap); 3798 else 3799 min_heap_pop(&event_heap, &perf_min_heap); 3800 } 3801 3802 return 0; 3803 } 3804 3805 /* 3806 * Because the userpage is strictly per-event (there is no concept of context, 3807 * so there cannot be a context indirection), every userpage must be updated 3808 * when context time starts :-( 3809 * 3810 * IOW, we must not miss EVENT_TIME edges. 3811 */ 3812 static inline bool event_update_userpage(struct perf_event *event) 3813 { 3814 if (likely(!atomic_read(&event->mmap_count))) 3815 return false; 3816 3817 perf_event_update_time(event); 3818 perf_event_update_userpage(event); 3819 3820 return true; 3821 } 3822 3823 static inline void group_update_userpage(struct perf_event *group_event) 3824 { 3825 struct perf_event *event; 3826 3827 if (!event_update_userpage(group_event)) 3828 return; 3829 3830 for_each_sibling_event(event, group_event) 3831 event_update_userpage(event); 3832 } 3833 3834 static int merge_sched_in(struct perf_event *event, void *data) 3835 { 3836 struct perf_event_context *ctx = event->ctx; 3837 int *can_add_hw = data; 3838 3839 if (event->state <= PERF_EVENT_STATE_OFF) 3840 return 0; 3841 3842 if (!event_filter_match(event)) 3843 return 0; 3844 3845 if (group_can_go_on(event, *can_add_hw)) { 3846 if (!group_sched_in(event, ctx)) 3847 list_add_tail(&event->active_list, get_event_list(event)); 3848 } 3849 3850 if (event->state == PERF_EVENT_STATE_INACTIVE) { 3851 *can_add_hw = 0; 3852 if (event->attr.pinned) { 3853 perf_cgroup_event_disable(event, ctx); 3854 perf_event_set_state(event, PERF_EVENT_STATE_ERROR); 3855 } else { 3856 struct perf_cpu_pmu_context *cpc; 3857 3858 event->pmu_ctx->rotate_necessary = 1; 3859 cpc = this_cpu_ptr(event->pmu_ctx->pmu->cpu_pmu_context); 3860 perf_mux_hrtimer_restart(cpc); 3861 group_update_userpage(event); 3862 } 3863 } 3864 3865 return 0; 3866 } 3867 3868 static void pmu_groups_sched_in(struct perf_event_context *ctx, 3869 struct perf_event_groups *groups, 3870 struct pmu *pmu) 3871 { 3872 int can_add_hw = 1; 3873 visit_groups_merge(ctx, groups, smp_processor_id(), pmu, 3874 merge_sched_in, &can_add_hw); 3875 } 3876 3877 static void ctx_groups_sched_in(struct perf_event_context *ctx, 3878 struct perf_event_groups *groups, 3879 bool cgroup) 3880 { 3881 struct perf_event_pmu_context *pmu_ctx; 3882 3883 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) { 3884 if (cgroup && !pmu_ctx->nr_cgroups) 3885 continue; 3886 pmu_groups_sched_in(ctx, groups, pmu_ctx->pmu); 3887 } 3888 } 3889 3890 static void __pmu_ctx_sched_in(struct perf_event_context *ctx, 3891 struct pmu *pmu) 3892 { 3893 pmu_groups_sched_in(ctx, &ctx->flexible_groups, pmu); 3894 } 3895 3896 static void 3897 ctx_sched_in(struct perf_event_context *ctx, enum event_type_t event_type) 3898 { 3899 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); 3900 int is_active = ctx->is_active; 3901 bool cgroup = event_type & EVENT_CGROUP; 3902 3903 event_type &= ~EVENT_CGROUP; 3904 3905 lockdep_assert_held(&ctx->lock); 3906 3907 if (likely(!ctx->nr_events)) 3908 return; 3909 3910 if (!(is_active & EVENT_TIME)) { 3911 /* start ctx time */ 3912 __update_context_time(ctx, false); 3913 perf_cgroup_set_timestamp(cpuctx); 3914 /* 3915 * CPU-release for the below ->is_active store, 3916 * see __load_acquire() in perf_event_time_now() 3917 */ 3918 barrier(); 3919 } 3920 3921 ctx->is_active |= (event_type | EVENT_TIME); 3922 if (ctx->task) { 3923 if (!is_active) 3924 cpuctx->task_ctx = ctx; 3925 else 3926 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 3927 } 3928 3929 is_active ^= ctx->is_active; /* changed bits */ 3930 3931 /* 3932 * First go through the list and put on any pinned groups 3933 * in order to give them the best chance of going on. 3934 */ 3935 if (is_active & EVENT_PINNED) 3936 ctx_groups_sched_in(ctx, &ctx->pinned_groups, cgroup); 3937 3938 /* Then walk through the lower prio flexible groups */ 3939 if (is_active & EVENT_FLEXIBLE) 3940 ctx_groups_sched_in(ctx, &ctx->flexible_groups, cgroup); 3941 } 3942 3943 static void perf_event_context_sched_in(struct task_struct *task) 3944 { 3945 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); 3946 struct perf_event_context *ctx; 3947 3948 rcu_read_lock(); 3949 ctx = rcu_dereference(task->perf_event_ctxp); 3950 if (!ctx) 3951 goto rcu_unlock; 3952 3953 if (cpuctx->task_ctx == ctx) { 3954 perf_ctx_lock(cpuctx, ctx); 3955 perf_ctx_disable(ctx, false); 3956 3957 perf_ctx_sched_task_cb(ctx, true); 3958 3959 perf_ctx_enable(ctx, false); 3960 perf_ctx_unlock(cpuctx, ctx); 3961 goto rcu_unlock; 3962 } 3963 3964 perf_ctx_lock(cpuctx, ctx); 3965 /* 3966 * We must check ctx->nr_events while holding ctx->lock, such 3967 * that we serialize against perf_install_in_context(). 3968 */ 3969 if (!ctx->nr_events) 3970 goto unlock; 3971 3972 perf_ctx_disable(ctx, false); 3973 /* 3974 * We want to keep the following priority order: 3975 * cpu pinned (that don't need to move), task pinned, 3976 * cpu flexible, task flexible. 3977 * 3978 * However, if task's ctx is not carrying any pinned 3979 * events, no need to flip the cpuctx's events around. 3980 */ 3981 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree)) { 3982 perf_ctx_disable(&cpuctx->ctx, false); 3983 ctx_sched_out(&cpuctx->ctx, EVENT_FLEXIBLE); 3984 } 3985 3986 perf_event_sched_in(cpuctx, ctx); 3987 3988 perf_ctx_sched_task_cb(cpuctx->task_ctx, true); 3989 3990 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree)) 3991 perf_ctx_enable(&cpuctx->ctx, false); 3992 3993 perf_ctx_enable(ctx, false); 3994 3995 unlock: 3996 perf_ctx_unlock(cpuctx, ctx); 3997 rcu_unlock: 3998 rcu_read_unlock(); 3999 } 4000 4001 /* 4002 * Called from scheduler to add the events of the current task 4003 * with interrupts disabled. 4004 * 4005 * We restore the event value and then enable it. 4006 * 4007 * This does not protect us against NMI, but enable() 4008 * sets the enabled bit in the control field of event _before_ 4009 * accessing the event control register. If a NMI hits, then it will 4010 * keep the event running. 4011 */ 4012 void __perf_event_task_sched_in(struct task_struct *prev, 4013 struct task_struct *task) 4014 { 4015 perf_event_context_sched_in(task); 4016 4017 if (atomic_read(&nr_switch_events)) 4018 perf_event_switch(task, prev, true); 4019 4020 if (__this_cpu_read(perf_sched_cb_usages)) 4021 perf_pmu_sched_task(prev, task, true); 4022 } 4023 4024 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count) 4025 { 4026 u64 frequency = event->attr.sample_freq; 4027 u64 sec = NSEC_PER_SEC; 4028 u64 divisor, dividend; 4029 4030 int count_fls, nsec_fls, frequency_fls, sec_fls; 4031 4032 count_fls = fls64(count); 4033 nsec_fls = fls64(nsec); 4034 frequency_fls = fls64(frequency); 4035 sec_fls = 30; 4036 4037 /* 4038 * We got @count in @nsec, with a target of sample_freq HZ 4039 * the target period becomes: 4040 * 4041 * @count * 10^9 4042 * period = ------------------- 4043 * @nsec * sample_freq 4044 * 4045 */ 4046 4047 /* 4048 * Reduce accuracy by one bit such that @a and @b converge 4049 * to a similar magnitude. 4050 */ 4051 #define REDUCE_FLS(a, b) \ 4052 do { \ 4053 if (a##_fls > b##_fls) { \ 4054 a >>= 1; \ 4055 a##_fls--; \ 4056 } else { \ 4057 b >>= 1; \ 4058 b##_fls--; \ 4059 } \ 4060 } while (0) 4061 4062 /* 4063 * Reduce accuracy until either term fits in a u64, then proceed with 4064 * the other, so that finally we can do a u64/u64 division. 4065 */ 4066 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) { 4067 REDUCE_FLS(nsec, frequency); 4068 REDUCE_FLS(sec, count); 4069 } 4070 4071 if (count_fls + sec_fls > 64) { 4072 divisor = nsec * frequency; 4073 4074 while (count_fls + sec_fls > 64) { 4075 REDUCE_FLS(count, sec); 4076 divisor >>= 1; 4077 } 4078 4079 dividend = count * sec; 4080 } else { 4081 dividend = count * sec; 4082 4083 while (nsec_fls + frequency_fls > 64) { 4084 REDUCE_FLS(nsec, frequency); 4085 dividend >>= 1; 4086 } 4087 4088 divisor = nsec * frequency; 4089 } 4090 4091 if (!divisor) 4092 return dividend; 4093 4094 return div64_u64(dividend, divisor); 4095 } 4096 4097 static DEFINE_PER_CPU(int, perf_throttled_count); 4098 static DEFINE_PER_CPU(u64, perf_throttled_seq); 4099 4100 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable) 4101 { 4102 struct hw_perf_event *hwc = &event->hw; 4103 s64 period, sample_period; 4104 s64 delta; 4105 4106 period = perf_calculate_period(event, nsec, count); 4107 4108 delta = (s64)(period - hwc->sample_period); 4109 delta = (delta + 7) / 8; /* low pass filter */ 4110 4111 sample_period = hwc->sample_period + delta; 4112 4113 if (!sample_period) 4114 sample_period = 1; 4115 4116 hwc->sample_period = sample_period; 4117 4118 if (local64_read(&hwc->period_left) > 8*sample_period) { 4119 if (disable) 4120 event->pmu->stop(event, PERF_EF_UPDATE); 4121 4122 local64_set(&hwc->period_left, 0); 4123 4124 if (disable) 4125 event->pmu->start(event, PERF_EF_RELOAD); 4126 } 4127 } 4128 4129 static void perf_adjust_freq_unthr_events(struct list_head *event_list) 4130 { 4131 struct perf_event *event; 4132 struct hw_perf_event *hwc; 4133 u64 now, period = TICK_NSEC; 4134 s64 delta; 4135 4136 list_for_each_entry(event, event_list, active_list) { 4137 if (event->state != PERF_EVENT_STATE_ACTIVE) 4138 continue; 4139 4140 // XXX use visit thingy to avoid the -1,cpu match 4141 if (!event_filter_match(event)) 4142 continue; 4143 4144 hwc = &event->hw; 4145 4146 if (hwc->interrupts == MAX_INTERRUPTS) { 4147 hwc->interrupts = 0; 4148 perf_log_throttle(event, 1); 4149 if (!event->attr.freq || !event->attr.sample_freq) 4150 event->pmu->start(event, 0); 4151 } 4152 4153 if (!event->attr.freq || !event->attr.sample_freq) 4154 continue; 4155 4156 /* 4157 * stop the event and update event->count 4158 */ 4159 event->pmu->stop(event, PERF_EF_UPDATE); 4160 4161 now = local64_read(&event->count); 4162 delta = now - hwc->freq_count_stamp; 4163 hwc->freq_count_stamp = now; 4164 4165 /* 4166 * restart the event 4167 * reload only if value has changed 4168 * we have stopped the event so tell that 4169 * to perf_adjust_period() to avoid stopping it 4170 * twice. 4171 */ 4172 if (delta > 0) 4173 perf_adjust_period(event, period, delta, false); 4174 4175 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0); 4176 } 4177 } 4178 4179 /* 4180 * combine freq adjustment with unthrottling to avoid two passes over the 4181 * events. At the same time, make sure, having freq events does not change 4182 * the rate of unthrottling as that would introduce bias. 4183 */ 4184 static void 4185 perf_adjust_freq_unthr_context(struct perf_event_context *ctx, bool unthrottle) 4186 { 4187 struct perf_event_pmu_context *pmu_ctx; 4188 4189 /* 4190 * only need to iterate over all events iff: 4191 * - context have events in frequency mode (needs freq adjust) 4192 * - there are events to unthrottle on this cpu 4193 */ 4194 if (!(ctx->nr_freq || unthrottle)) 4195 return; 4196 4197 raw_spin_lock(&ctx->lock); 4198 4199 list_for_each_entry(pmu_ctx, &ctx->pmu_ctx_list, pmu_ctx_entry) { 4200 if (!(pmu_ctx->nr_freq || unthrottle)) 4201 continue; 4202 if (!perf_pmu_ctx_is_active(pmu_ctx)) 4203 continue; 4204 if (pmu_ctx->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) 4205 continue; 4206 4207 perf_pmu_disable(pmu_ctx->pmu); 4208 perf_adjust_freq_unthr_events(&pmu_ctx->pinned_active); 4209 perf_adjust_freq_unthr_events(&pmu_ctx->flexible_active); 4210 perf_pmu_enable(pmu_ctx->pmu); 4211 } 4212 4213 raw_spin_unlock(&ctx->lock); 4214 } 4215 4216 /* 4217 * Move @event to the tail of the @ctx's elegible events. 4218 */ 4219 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event) 4220 { 4221 /* 4222 * Rotate the first entry last of non-pinned groups. Rotation might be 4223 * disabled by the inheritance code. 4224 */ 4225 if (ctx->rotate_disable) 4226 return; 4227 4228 perf_event_groups_delete(&ctx->flexible_groups, event); 4229 perf_event_groups_insert(&ctx->flexible_groups, event); 4230 } 4231 4232 /* pick an event from the flexible_groups to rotate */ 4233 static inline struct perf_event * 4234 ctx_event_to_rotate(struct perf_event_pmu_context *pmu_ctx) 4235 { 4236 struct perf_event *event; 4237 struct rb_node *node; 4238 struct rb_root *tree; 4239 struct __group_key key = { 4240 .pmu = pmu_ctx->pmu, 4241 }; 4242 4243 /* pick the first active flexible event */ 4244 event = list_first_entry_or_null(&pmu_ctx->flexible_active, 4245 struct perf_event, active_list); 4246 if (event) 4247 goto out; 4248 4249 /* if no active flexible event, pick the first event */ 4250 tree = &pmu_ctx->ctx->flexible_groups.tree; 4251 4252 if (!pmu_ctx->ctx->task) { 4253 key.cpu = smp_processor_id(); 4254 4255 node = rb_find_first(&key, tree, __group_cmp_ignore_cgroup); 4256 if (node) 4257 event = __node_2_pe(node); 4258 goto out; 4259 } 4260 4261 key.cpu = -1; 4262 node = rb_find_first(&key, tree, __group_cmp_ignore_cgroup); 4263 if (node) { 4264 event = __node_2_pe(node); 4265 goto out; 4266 } 4267 4268 key.cpu = smp_processor_id(); 4269 node = rb_find_first(&key, tree, __group_cmp_ignore_cgroup); 4270 if (node) 4271 event = __node_2_pe(node); 4272 4273 out: 4274 /* 4275 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in() 4276 * finds there are unschedulable events, it will set it again. 4277 */ 4278 pmu_ctx->rotate_necessary = 0; 4279 4280 return event; 4281 } 4282 4283 static bool perf_rotate_context(struct perf_cpu_pmu_context *cpc) 4284 { 4285 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); 4286 struct perf_event_pmu_context *cpu_epc, *task_epc = NULL; 4287 struct perf_event *cpu_event = NULL, *task_event = NULL; 4288 int cpu_rotate, task_rotate; 4289 struct pmu *pmu; 4290 4291 /* 4292 * Since we run this from IRQ context, nobody can install new 4293 * events, thus the event count values are stable. 4294 */ 4295 4296 cpu_epc = &cpc->epc; 4297 pmu = cpu_epc->pmu; 4298 task_epc = cpc->task_epc; 4299 4300 cpu_rotate = cpu_epc->rotate_necessary; 4301 task_rotate = task_epc ? task_epc->rotate_necessary : 0; 4302 4303 if (!(cpu_rotate || task_rotate)) 4304 return false; 4305 4306 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 4307 perf_pmu_disable(pmu); 4308 4309 if (task_rotate) 4310 task_event = ctx_event_to_rotate(task_epc); 4311 if (cpu_rotate) 4312 cpu_event = ctx_event_to_rotate(cpu_epc); 4313 4314 /* 4315 * As per the order given at ctx_resched() first 'pop' task flexible 4316 * and then, if needed CPU flexible. 4317 */ 4318 if (task_event || (task_epc && cpu_event)) { 4319 update_context_time(task_epc->ctx); 4320 __pmu_ctx_sched_out(task_epc, EVENT_FLEXIBLE); 4321 } 4322 4323 if (cpu_event) { 4324 update_context_time(&cpuctx->ctx); 4325 __pmu_ctx_sched_out(cpu_epc, EVENT_FLEXIBLE); 4326 rotate_ctx(&cpuctx->ctx, cpu_event); 4327 __pmu_ctx_sched_in(&cpuctx->ctx, pmu); 4328 } 4329 4330 if (task_event) 4331 rotate_ctx(task_epc->ctx, task_event); 4332 4333 if (task_event || (task_epc && cpu_event)) 4334 __pmu_ctx_sched_in(task_epc->ctx, pmu); 4335 4336 perf_pmu_enable(pmu); 4337 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 4338 4339 return true; 4340 } 4341 4342 void perf_event_task_tick(void) 4343 { 4344 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); 4345 struct perf_event_context *ctx; 4346 int throttled; 4347 4348 lockdep_assert_irqs_disabled(); 4349 4350 __this_cpu_inc(perf_throttled_seq); 4351 throttled = __this_cpu_xchg(perf_throttled_count, 0); 4352 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); 4353 4354 perf_adjust_freq_unthr_context(&cpuctx->ctx, !!throttled); 4355 4356 rcu_read_lock(); 4357 ctx = rcu_dereference(current->perf_event_ctxp); 4358 if (ctx) 4359 perf_adjust_freq_unthr_context(ctx, !!throttled); 4360 rcu_read_unlock(); 4361 } 4362 4363 static int event_enable_on_exec(struct perf_event *event, 4364 struct perf_event_context *ctx) 4365 { 4366 if (!event->attr.enable_on_exec) 4367 return 0; 4368 4369 event->attr.enable_on_exec = 0; 4370 if (event->state >= PERF_EVENT_STATE_INACTIVE) 4371 return 0; 4372 4373 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE); 4374 4375 return 1; 4376 } 4377 4378 /* 4379 * Enable all of a task's events that have been marked enable-on-exec. 4380 * This expects task == current. 4381 */ 4382 static void perf_event_enable_on_exec(struct perf_event_context *ctx) 4383 { 4384 struct perf_event_context *clone_ctx = NULL; 4385 enum event_type_t event_type = 0; 4386 struct perf_cpu_context *cpuctx; 4387 struct perf_event *event; 4388 unsigned long flags; 4389 int enabled = 0; 4390 4391 local_irq_save(flags); 4392 if (WARN_ON_ONCE(current->perf_event_ctxp != ctx)) 4393 goto out; 4394 4395 if (!ctx->nr_events) 4396 goto out; 4397 4398 cpuctx = this_cpu_ptr(&perf_cpu_context); 4399 perf_ctx_lock(cpuctx, ctx); 4400 ctx_sched_out(ctx, EVENT_TIME); 4401 4402 list_for_each_entry(event, &ctx->event_list, event_entry) { 4403 enabled |= event_enable_on_exec(event, ctx); 4404 event_type |= get_event_type(event); 4405 } 4406 4407 /* 4408 * Unclone and reschedule this context if we enabled any event. 4409 */ 4410 if (enabled) { 4411 clone_ctx = unclone_ctx(ctx); 4412 ctx_resched(cpuctx, ctx, event_type); 4413 } else { 4414 ctx_sched_in(ctx, EVENT_TIME); 4415 } 4416 perf_ctx_unlock(cpuctx, ctx); 4417 4418 out: 4419 local_irq_restore(flags); 4420 4421 if (clone_ctx) 4422 put_ctx(clone_ctx); 4423 } 4424 4425 static void perf_remove_from_owner(struct perf_event *event); 4426 static void perf_event_exit_event(struct perf_event *event, 4427 struct perf_event_context *ctx); 4428 4429 /* 4430 * Removes all events from the current task that have been marked 4431 * remove-on-exec, and feeds their values back to parent events. 4432 */ 4433 static void perf_event_remove_on_exec(struct perf_event_context *ctx) 4434 { 4435 struct perf_event_context *clone_ctx = NULL; 4436 struct perf_event *event, *next; 4437 unsigned long flags; 4438 bool modified = false; 4439 4440 mutex_lock(&ctx->mutex); 4441 4442 if (WARN_ON_ONCE(ctx->task != current)) 4443 goto unlock; 4444 4445 list_for_each_entry_safe(event, next, &ctx->event_list, event_entry) { 4446 if (!event->attr.remove_on_exec) 4447 continue; 4448 4449 if (!is_kernel_event(event)) 4450 perf_remove_from_owner(event); 4451 4452 modified = true; 4453 4454 perf_event_exit_event(event, ctx); 4455 } 4456 4457 raw_spin_lock_irqsave(&ctx->lock, flags); 4458 if (modified) 4459 clone_ctx = unclone_ctx(ctx); 4460 raw_spin_unlock_irqrestore(&ctx->lock, flags); 4461 4462 unlock: 4463 mutex_unlock(&ctx->mutex); 4464 4465 if (clone_ctx) 4466 put_ctx(clone_ctx); 4467 } 4468 4469 struct perf_read_data { 4470 struct perf_event *event; 4471 bool group; 4472 int ret; 4473 }; 4474 4475 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu) 4476 { 4477 u16 local_pkg, event_pkg; 4478 4479 if ((unsigned)event_cpu >= nr_cpu_ids) 4480 return event_cpu; 4481 4482 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) { 4483 int local_cpu = smp_processor_id(); 4484 4485 event_pkg = topology_physical_package_id(event_cpu); 4486 local_pkg = topology_physical_package_id(local_cpu); 4487 4488 if (event_pkg == local_pkg) 4489 return local_cpu; 4490 } 4491 4492 return event_cpu; 4493 } 4494 4495 /* 4496 * Cross CPU call to read the hardware event 4497 */ 4498 static void __perf_event_read(void *info) 4499 { 4500 struct perf_read_data *data = info; 4501 struct perf_event *sub, *event = data->event; 4502 struct perf_event_context *ctx = event->ctx; 4503 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); 4504 struct pmu *pmu = event->pmu; 4505 4506 /* 4507 * If this is a task context, we need to check whether it is 4508 * the current task context of this cpu. If not it has been 4509 * scheduled out before the smp call arrived. In that case 4510 * event->count would have been updated to a recent sample 4511 * when the event was scheduled out. 4512 */ 4513 if (ctx->task && cpuctx->task_ctx != ctx) 4514 return; 4515 4516 raw_spin_lock(&ctx->lock); 4517 if (ctx->is_active & EVENT_TIME) { 4518 update_context_time(ctx); 4519 update_cgrp_time_from_event(event); 4520 } 4521 4522 perf_event_update_time(event); 4523 if (data->group) 4524 perf_event_update_sibling_time(event); 4525 4526 if (event->state != PERF_EVENT_STATE_ACTIVE) 4527 goto unlock; 4528 4529 if (!data->group) { 4530 pmu->read(event); 4531 data->ret = 0; 4532 goto unlock; 4533 } 4534 4535 pmu->start_txn(pmu, PERF_PMU_TXN_READ); 4536 4537 pmu->read(event); 4538 4539 for_each_sibling_event(sub, event) { 4540 if (sub->state == PERF_EVENT_STATE_ACTIVE) { 4541 /* 4542 * Use sibling's PMU rather than @event's since 4543 * sibling could be on different (eg: software) PMU. 4544 */ 4545 sub->pmu->read(sub); 4546 } 4547 } 4548 4549 data->ret = pmu->commit_txn(pmu); 4550 4551 unlock: 4552 raw_spin_unlock(&ctx->lock); 4553 } 4554 4555 static inline u64 perf_event_count(struct perf_event *event) 4556 { 4557 return local64_read(&event->count) + atomic64_read(&event->child_count); 4558 } 4559 4560 static void calc_timer_values(struct perf_event *event, 4561 u64 *now, 4562 u64 *enabled, 4563 u64 *running) 4564 { 4565 u64 ctx_time; 4566 4567 *now = perf_clock(); 4568 ctx_time = perf_event_time_now(event, *now); 4569 __perf_update_times(event, ctx_time, enabled, running); 4570 } 4571 4572 /* 4573 * NMI-safe method to read a local event, that is an event that 4574 * is: 4575 * - either for the current task, or for this CPU 4576 * - does not have inherit set, for inherited task events 4577 * will not be local and we cannot read them atomically 4578 * - must not have a pmu::count method 4579 */ 4580 int perf_event_read_local(struct perf_event *event, u64 *value, 4581 u64 *enabled, u64 *running) 4582 { 4583 unsigned long flags; 4584 int event_oncpu; 4585 int event_cpu; 4586 int ret = 0; 4587 4588 /* 4589 * Disabling interrupts avoids all counter scheduling (context 4590 * switches, timer based rotation and IPIs). 4591 */ 4592 local_irq_save(flags); 4593 4594 /* 4595 * It must not be an event with inherit set, we cannot read 4596 * all child counters from atomic context. 4597 */ 4598 if (event->attr.inherit) { 4599 ret = -EOPNOTSUPP; 4600 goto out; 4601 } 4602 4603 /* If this is a per-task event, it must be for current */ 4604 if ((event->attach_state & PERF_ATTACH_TASK) && 4605 event->hw.target != current) { 4606 ret = -EINVAL; 4607 goto out; 4608 } 4609 4610 /* 4611 * Get the event CPU numbers, and adjust them to local if the event is 4612 * a per-package event that can be read locally 4613 */ 4614 event_oncpu = __perf_event_read_cpu(event, event->oncpu); 4615 event_cpu = __perf_event_read_cpu(event, event->cpu); 4616 4617 /* If this is a per-CPU event, it must be for this CPU */ 4618 if (!(event->attach_state & PERF_ATTACH_TASK) && 4619 event_cpu != smp_processor_id()) { 4620 ret = -EINVAL; 4621 goto out; 4622 } 4623 4624 /* If this is a pinned event it must be running on this CPU */ 4625 if (event->attr.pinned && event_oncpu != smp_processor_id()) { 4626 ret = -EBUSY; 4627 goto out; 4628 } 4629 4630 /* 4631 * If the event is currently on this CPU, its either a per-task event, 4632 * or local to this CPU. Furthermore it means its ACTIVE (otherwise 4633 * oncpu == -1). 4634 */ 4635 if (event_oncpu == smp_processor_id()) 4636 event->pmu->read(event); 4637 4638 *value = local64_read(&event->count); 4639 if (enabled || running) { 4640 u64 __enabled, __running, __now; 4641 4642 calc_timer_values(event, &__now, &__enabled, &__running); 4643 if (enabled) 4644 *enabled = __enabled; 4645 if (running) 4646 *running = __running; 4647 } 4648 out: 4649 local_irq_restore(flags); 4650 4651 return ret; 4652 } 4653 4654 static int perf_event_read(struct perf_event *event, bool group) 4655 { 4656 enum perf_event_state state = READ_ONCE(event->state); 4657 int event_cpu, ret = 0; 4658 4659 /* 4660 * If event is enabled and currently active on a CPU, update the 4661 * value in the event structure: 4662 */ 4663 again: 4664 if (state == PERF_EVENT_STATE_ACTIVE) { 4665 struct perf_read_data data; 4666 4667 /* 4668 * Orders the ->state and ->oncpu loads such that if we see 4669 * ACTIVE we must also see the right ->oncpu. 4670 * 4671 * Matches the smp_wmb() from event_sched_in(). 4672 */ 4673 smp_rmb(); 4674 4675 event_cpu = READ_ONCE(event->oncpu); 4676 if ((unsigned)event_cpu >= nr_cpu_ids) 4677 return 0; 4678 4679 data = (struct perf_read_data){ 4680 .event = event, 4681 .group = group, 4682 .ret = 0, 4683 }; 4684 4685 preempt_disable(); 4686 event_cpu = __perf_event_read_cpu(event, event_cpu); 4687 4688 /* 4689 * Purposely ignore the smp_call_function_single() return 4690 * value. 4691 * 4692 * If event_cpu isn't a valid CPU it means the event got 4693 * scheduled out and that will have updated the event count. 4694 * 4695 * Therefore, either way, we'll have an up-to-date event count 4696 * after this. 4697 */ 4698 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1); 4699 preempt_enable(); 4700 ret = data.ret; 4701 4702 } else if (state == PERF_EVENT_STATE_INACTIVE) { 4703 struct perf_event_context *ctx = event->ctx; 4704 unsigned long flags; 4705 4706 raw_spin_lock_irqsave(&ctx->lock, flags); 4707 state = event->state; 4708 if (state != PERF_EVENT_STATE_INACTIVE) { 4709 raw_spin_unlock_irqrestore(&ctx->lock, flags); 4710 goto again; 4711 } 4712 4713 /* 4714 * May read while context is not active (e.g., thread is 4715 * blocked), in that case we cannot update context time 4716 */ 4717 if (ctx->is_active & EVENT_TIME) { 4718 update_context_time(ctx); 4719 update_cgrp_time_from_event(event); 4720 } 4721 4722 perf_event_update_time(event); 4723 if (group) 4724 perf_event_update_sibling_time(event); 4725 raw_spin_unlock_irqrestore(&ctx->lock, flags); 4726 } 4727 4728 return ret; 4729 } 4730 4731 /* 4732 * Initialize the perf_event context in a task_struct: 4733 */ 4734 static void __perf_event_init_context(struct perf_event_context *ctx) 4735 { 4736 raw_spin_lock_init(&ctx->lock); 4737 mutex_init(&ctx->mutex); 4738 INIT_LIST_HEAD(&ctx->pmu_ctx_list); 4739 perf_event_groups_init(&ctx->pinned_groups); 4740 perf_event_groups_init(&ctx->flexible_groups); 4741 INIT_LIST_HEAD(&ctx->event_list); 4742 refcount_set(&ctx->refcount, 1); 4743 } 4744 4745 static void 4746 __perf_init_event_pmu_context(struct perf_event_pmu_context *epc, struct pmu *pmu) 4747 { 4748 epc->pmu = pmu; 4749 INIT_LIST_HEAD(&epc->pmu_ctx_entry); 4750 INIT_LIST_HEAD(&epc->pinned_active); 4751 INIT_LIST_HEAD(&epc->flexible_active); 4752 atomic_set(&epc->refcount, 1); 4753 } 4754 4755 static struct perf_event_context * 4756 alloc_perf_context(struct task_struct *task) 4757 { 4758 struct perf_event_context *ctx; 4759 4760 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL); 4761 if (!ctx) 4762 return NULL; 4763 4764 __perf_event_init_context(ctx); 4765 if (task) 4766 ctx->task = get_task_struct(task); 4767 4768 return ctx; 4769 } 4770 4771 static struct task_struct * 4772 find_lively_task_by_vpid(pid_t vpid) 4773 { 4774 struct task_struct *task; 4775 4776 rcu_read_lock(); 4777 if (!vpid) 4778 task = current; 4779 else 4780 task = find_task_by_vpid(vpid); 4781 if (task) 4782 get_task_struct(task); 4783 rcu_read_unlock(); 4784 4785 if (!task) 4786 return ERR_PTR(-ESRCH); 4787 4788 return task; 4789 } 4790 4791 /* 4792 * Returns a matching context with refcount and pincount. 4793 */ 4794 static struct perf_event_context * 4795 find_get_context(struct task_struct *task, struct perf_event *event) 4796 { 4797 struct perf_event_context *ctx, *clone_ctx = NULL; 4798 struct perf_cpu_context *cpuctx; 4799 unsigned long flags; 4800 int err; 4801 4802 if (!task) { 4803 /* Must be root to operate on a CPU event: */ 4804 err = perf_allow_cpu(&event->attr); 4805 if (err) 4806 return ERR_PTR(err); 4807 4808 cpuctx = per_cpu_ptr(&perf_cpu_context, event->cpu); 4809 ctx = &cpuctx->ctx; 4810 get_ctx(ctx); 4811 raw_spin_lock_irqsave(&ctx->lock, flags); 4812 ++ctx->pin_count; 4813 raw_spin_unlock_irqrestore(&ctx->lock, flags); 4814 4815 return ctx; 4816 } 4817 4818 err = -EINVAL; 4819 retry: 4820 ctx = perf_lock_task_context(task, &flags); 4821 if (ctx) { 4822 clone_ctx = unclone_ctx(ctx); 4823 ++ctx->pin_count; 4824 4825 raw_spin_unlock_irqrestore(&ctx->lock, flags); 4826 4827 if (clone_ctx) 4828 put_ctx(clone_ctx); 4829 } else { 4830 ctx = alloc_perf_context(task); 4831 err = -ENOMEM; 4832 if (!ctx) 4833 goto errout; 4834 4835 err = 0; 4836 mutex_lock(&task->perf_event_mutex); 4837 /* 4838 * If it has already passed perf_event_exit_task(). 4839 * we must see PF_EXITING, it takes this mutex too. 4840 */ 4841 if (task->flags & PF_EXITING) 4842 err = -ESRCH; 4843 else if (task->perf_event_ctxp) 4844 err = -EAGAIN; 4845 else { 4846 get_ctx(ctx); 4847 ++ctx->pin_count; 4848 rcu_assign_pointer(task->perf_event_ctxp, ctx); 4849 } 4850 mutex_unlock(&task->perf_event_mutex); 4851 4852 if (unlikely(err)) { 4853 put_ctx(ctx); 4854 4855 if (err == -EAGAIN) 4856 goto retry; 4857 goto errout; 4858 } 4859 } 4860 4861 return ctx; 4862 4863 errout: 4864 return ERR_PTR(err); 4865 } 4866 4867 static struct perf_event_pmu_context * 4868 find_get_pmu_context(struct pmu *pmu, struct perf_event_context *ctx, 4869 struct perf_event *event) 4870 { 4871 struct perf_event_pmu_context *new = NULL, *epc; 4872 void *task_ctx_data = NULL; 4873 4874 if (!ctx->task) { 4875 /* 4876 * perf_pmu_migrate_context() / __perf_pmu_install_event() 4877 * relies on the fact that find_get_pmu_context() cannot fail 4878 * for CPU contexts. 4879 */ 4880 struct perf_cpu_pmu_context *cpc; 4881 4882 cpc = per_cpu_ptr(pmu->cpu_pmu_context, event->cpu); 4883 epc = &cpc->epc; 4884 raw_spin_lock_irq(&ctx->lock); 4885 if (!epc->ctx) { 4886 atomic_set(&epc->refcount, 1); 4887 epc->embedded = 1; 4888 list_add(&epc->pmu_ctx_entry, &ctx->pmu_ctx_list); 4889 epc->ctx = ctx; 4890 } else { 4891 WARN_ON_ONCE(epc->ctx != ctx); 4892 atomic_inc(&epc->refcount); 4893 } 4894 raw_spin_unlock_irq(&ctx->lock); 4895 return epc; 4896 } 4897 4898 new = kzalloc(sizeof(*epc), GFP_KERNEL); 4899 if (!new) 4900 return ERR_PTR(-ENOMEM); 4901 4902 if (event->attach_state & PERF_ATTACH_TASK_DATA) { 4903 task_ctx_data = alloc_task_ctx_data(pmu); 4904 if (!task_ctx_data) { 4905 kfree(new); 4906 return ERR_PTR(-ENOMEM); 4907 } 4908 } 4909 4910 __perf_init_event_pmu_context(new, pmu); 4911 4912 /* 4913 * XXX 4914 * 4915 * lockdep_assert_held(&ctx->mutex); 4916 * 4917 * can't because perf_event_init_task() doesn't actually hold the 4918 * child_ctx->mutex. 4919 */ 4920 4921 raw_spin_lock_irq(&ctx->lock); 4922 list_for_each_entry(epc, &ctx->pmu_ctx_list, pmu_ctx_entry) { 4923 if (epc->pmu == pmu) { 4924 WARN_ON_ONCE(epc->ctx != ctx); 4925 atomic_inc(&epc->refcount); 4926 goto found_epc; 4927 } 4928 } 4929 4930 epc = new; 4931 new = NULL; 4932 4933 list_add(&epc->pmu_ctx_entry, &ctx->pmu_ctx_list); 4934 epc->ctx = ctx; 4935 4936 found_epc: 4937 if (task_ctx_data && !epc->task_ctx_data) { 4938 epc->task_ctx_data = task_ctx_data; 4939 task_ctx_data = NULL; 4940 ctx->nr_task_data++; 4941 } 4942 raw_spin_unlock_irq(&ctx->lock); 4943 4944 free_task_ctx_data(pmu, task_ctx_data); 4945 kfree(new); 4946 4947 return epc; 4948 } 4949 4950 static void get_pmu_ctx(struct perf_event_pmu_context *epc) 4951 { 4952 WARN_ON_ONCE(!atomic_inc_not_zero(&epc->refcount)); 4953 } 4954 4955 static void free_epc_rcu(struct rcu_head *head) 4956 { 4957 struct perf_event_pmu_context *epc = container_of(head, typeof(*epc), rcu_head); 4958 4959 kfree(epc->task_ctx_data); 4960 kfree(epc); 4961 } 4962 4963 static void put_pmu_ctx(struct perf_event_pmu_context *epc) 4964 { 4965 struct perf_event_context *ctx = epc->ctx; 4966 unsigned long flags; 4967 4968 /* 4969 * XXX 4970 * 4971 * lockdep_assert_held(&ctx->mutex); 4972 * 4973 * can't because of the call-site in _free_event()/put_event() 4974 * which isn't always called under ctx->mutex. 4975 */ 4976 if (!atomic_dec_and_raw_lock_irqsave(&epc->refcount, &ctx->lock, flags)) 4977 return; 4978 4979 WARN_ON_ONCE(list_empty(&epc->pmu_ctx_entry)); 4980 4981 list_del_init(&epc->pmu_ctx_entry); 4982 epc->ctx = NULL; 4983 4984 WARN_ON_ONCE(!list_empty(&epc->pinned_active)); 4985 WARN_ON_ONCE(!list_empty(&epc->flexible_active)); 4986 4987 raw_spin_unlock_irqrestore(&ctx->lock, flags); 4988 4989 if (epc->embedded) 4990 return; 4991 4992 call_rcu(&epc->rcu_head, free_epc_rcu); 4993 } 4994 4995 static void perf_event_free_filter(struct perf_event *event); 4996 4997 static void free_event_rcu(struct rcu_head *head) 4998 { 4999 struct perf_event *event = container_of(head, typeof(*event), rcu_head); 5000 5001 if (event->ns) 5002 put_pid_ns(event->ns); 5003 perf_event_free_filter(event); 5004 kmem_cache_free(perf_event_cache, event); 5005 } 5006 5007 static void ring_buffer_attach(struct perf_event *event, 5008 struct perf_buffer *rb); 5009 5010 static void detach_sb_event(struct perf_event *event) 5011 { 5012 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu); 5013 5014 raw_spin_lock(&pel->lock); 5015 list_del_rcu(&event->sb_list); 5016 raw_spin_unlock(&pel->lock); 5017 } 5018 5019 static bool is_sb_event(struct perf_event *event) 5020 { 5021 struct perf_event_attr *attr = &event->attr; 5022 5023 if (event->parent) 5024 return false; 5025 5026 if (event->attach_state & PERF_ATTACH_TASK) 5027 return false; 5028 5029 if (attr->mmap || attr->mmap_data || attr->mmap2 || 5030 attr->comm || attr->comm_exec || 5031 attr->task || attr->ksymbol || 5032 attr->context_switch || attr->text_poke || 5033 attr->bpf_event) 5034 return true; 5035 return false; 5036 } 5037 5038 static void unaccount_pmu_sb_event(struct perf_event *event) 5039 { 5040 if (is_sb_event(event)) 5041 detach_sb_event(event); 5042 } 5043 5044 #ifdef CONFIG_NO_HZ_FULL 5045 static DEFINE_SPINLOCK(nr_freq_lock); 5046 #endif 5047 5048 static void unaccount_freq_event_nohz(void) 5049 { 5050 #ifdef CONFIG_NO_HZ_FULL 5051 spin_lock(&nr_freq_lock); 5052 if (atomic_dec_and_test(&nr_freq_events)) 5053 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS); 5054 spin_unlock(&nr_freq_lock); 5055 #endif 5056 } 5057 5058 static void unaccount_freq_event(void) 5059 { 5060 if (tick_nohz_full_enabled()) 5061 unaccount_freq_event_nohz(); 5062 else 5063 atomic_dec(&nr_freq_events); 5064 } 5065 5066 static void unaccount_event(struct perf_event *event) 5067 { 5068 bool dec = false; 5069 5070 if (event->parent) 5071 return; 5072 5073 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB)) 5074 dec = true; 5075 if (event->attr.mmap || event->attr.mmap_data) 5076 atomic_dec(&nr_mmap_events); 5077 if (event->attr.build_id) 5078 atomic_dec(&nr_build_id_events); 5079 if (event->attr.comm) 5080 atomic_dec(&nr_comm_events); 5081 if (event->attr.namespaces) 5082 atomic_dec(&nr_namespaces_events); 5083 if (event->attr.cgroup) 5084 atomic_dec(&nr_cgroup_events); 5085 if (event->attr.task) 5086 atomic_dec(&nr_task_events); 5087 if (event->attr.freq) 5088 unaccount_freq_event(); 5089 if (event->attr.context_switch) { 5090 dec = true; 5091 atomic_dec(&nr_switch_events); 5092 } 5093 if (is_cgroup_event(event)) 5094 dec = true; 5095 if (has_branch_stack(event)) 5096 dec = true; 5097 if (event->attr.ksymbol) 5098 atomic_dec(&nr_ksymbol_events); 5099 if (event->attr.bpf_event) 5100 atomic_dec(&nr_bpf_events); 5101 if (event->attr.text_poke) 5102 atomic_dec(&nr_text_poke_events); 5103 5104 if (dec) { 5105 if (!atomic_add_unless(&perf_sched_count, -1, 1)) 5106 schedule_delayed_work(&perf_sched_work, HZ); 5107 } 5108 5109 unaccount_pmu_sb_event(event); 5110 } 5111 5112 static void perf_sched_delayed(struct work_struct *work) 5113 { 5114 mutex_lock(&perf_sched_mutex); 5115 if (atomic_dec_and_test(&perf_sched_count)) 5116 static_branch_disable(&perf_sched_events); 5117 mutex_unlock(&perf_sched_mutex); 5118 } 5119 5120 /* 5121 * The following implement mutual exclusion of events on "exclusive" pmus 5122 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled 5123 * at a time, so we disallow creating events that might conflict, namely: 5124 * 5125 * 1) cpu-wide events in the presence of per-task events, 5126 * 2) per-task events in the presence of cpu-wide events, 5127 * 3) two matching events on the same perf_event_context. 5128 * 5129 * The former two cases are handled in the allocation path (perf_event_alloc(), 5130 * _free_event()), the latter -- before the first perf_install_in_context(). 5131 */ 5132 static int exclusive_event_init(struct perf_event *event) 5133 { 5134 struct pmu *pmu = event->pmu; 5135 5136 if (!is_exclusive_pmu(pmu)) 5137 return 0; 5138 5139 /* 5140 * Prevent co-existence of per-task and cpu-wide events on the 5141 * same exclusive pmu. 5142 * 5143 * Negative pmu::exclusive_cnt means there are cpu-wide 5144 * events on this "exclusive" pmu, positive means there are 5145 * per-task events. 5146 * 5147 * Since this is called in perf_event_alloc() path, event::ctx 5148 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK 5149 * to mean "per-task event", because unlike other attach states it 5150 * never gets cleared. 5151 */ 5152 if (event->attach_state & PERF_ATTACH_TASK) { 5153 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt)) 5154 return -EBUSY; 5155 } else { 5156 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt)) 5157 return -EBUSY; 5158 } 5159 5160 return 0; 5161 } 5162 5163 static void exclusive_event_destroy(struct perf_event *event) 5164 { 5165 struct pmu *pmu = event->pmu; 5166 5167 if (!is_exclusive_pmu(pmu)) 5168 return; 5169 5170 /* see comment in exclusive_event_init() */ 5171 if (event->attach_state & PERF_ATTACH_TASK) 5172 atomic_dec(&pmu->exclusive_cnt); 5173 else 5174 atomic_inc(&pmu->exclusive_cnt); 5175 } 5176 5177 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2) 5178 { 5179 if ((e1->pmu == e2->pmu) && 5180 (e1->cpu == e2->cpu || 5181 e1->cpu == -1 || 5182 e2->cpu == -1)) 5183 return true; 5184 return false; 5185 } 5186 5187 static bool exclusive_event_installable(struct perf_event *event, 5188 struct perf_event_context *ctx) 5189 { 5190 struct perf_event *iter_event; 5191 struct pmu *pmu = event->pmu; 5192 5193 lockdep_assert_held(&ctx->mutex); 5194 5195 if (!is_exclusive_pmu(pmu)) 5196 return true; 5197 5198 list_for_each_entry(iter_event, &ctx->event_list, event_entry) { 5199 if (exclusive_event_match(iter_event, event)) 5200 return false; 5201 } 5202 5203 return true; 5204 } 5205 5206 static void perf_addr_filters_splice(struct perf_event *event, 5207 struct list_head *head); 5208 5209 static void _free_event(struct perf_event *event) 5210 { 5211 irq_work_sync(&event->pending_irq); 5212 5213 unaccount_event(event); 5214 5215 security_perf_event_free(event); 5216 5217 if (event->rb) { 5218 /* 5219 * Can happen when we close an event with re-directed output. 5220 * 5221 * Since we have a 0 refcount, perf_mmap_close() will skip 5222 * over us; possibly making our ring_buffer_put() the last. 5223 */ 5224 mutex_lock(&event->mmap_mutex); 5225 ring_buffer_attach(event, NULL); 5226 mutex_unlock(&event->mmap_mutex); 5227 } 5228 5229 if (is_cgroup_event(event)) 5230 perf_detach_cgroup(event); 5231 5232 if (!event->parent) { 5233 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) 5234 put_callchain_buffers(); 5235 } 5236 5237 perf_event_free_bpf_prog(event); 5238 perf_addr_filters_splice(event, NULL); 5239 kfree(event->addr_filter_ranges); 5240 5241 if (event->destroy) 5242 event->destroy(event); 5243 5244 /* 5245 * Must be after ->destroy(), due to uprobe_perf_close() using 5246 * hw.target. 5247 */ 5248 if (event->hw.target) 5249 put_task_struct(event->hw.target); 5250 5251 if (event->pmu_ctx) 5252 put_pmu_ctx(event->pmu_ctx); 5253 5254 /* 5255 * perf_event_free_task() relies on put_ctx() being 'last', in particular 5256 * all task references must be cleaned up. 5257 */ 5258 if (event->ctx) 5259 put_ctx(event->ctx); 5260 5261 exclusive_event_destroy(event); 5262 module_put(event->pmu->module); 5263 5264 call_rcu(&event->rcu_head, free_event_rcu); 5265 } 5266 5267 /* 5268 * Used to free events which have a known refcount of 1, such as in error paths 5269 * where the event isn't exposed yet and inherited events. 5270 */ 5271 static void free_event(struct perf_event *event) 5272 { 5273 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1, 5274 "unexpected event refcount: %ld; ptr=%p\n", 5275 atomic_long_read(&event->refcount), event)) { 5276 /* leak to avoid use-after-free */ 5277 return; 5278 } 5279 5280 _free_event(event); 5281 } 5282 5283 /* 5284 * Remove user event from the owner task. 5285 */ 5286 static void perf_remove_from_owner(struct perf_event *event) 5287 { 5288 struct task_struct *owner; 5289 5290 rcu_read_lock(); 5291 /* 5292 * Matches the smp_store_release() in perf_event_exit_task(). If we 5293 * observe !owner it means the list deletion is complete and we can 5294 * indeed free this event, otherwise we need to serialize on 5295 * owner->perf_event_mutex. 5296 */ 5297 owner = READ_ONCE(event->owner); 5298 if (owner) { 5299 /* 5300 * Since delayed_put_task_struct() also drops the last 5301 * task reference we can safely take a new reference 5302 * while holding the rcu_read_lock(). 5303 */ 5304 get_task_struct(owner); 5305 } 5306 rcu_read_unlock(); 5307 5308 if (owner) { 5309 /* 5310 * If we're here through perf_event_exit_task() we're already 5311 * holding ctx->mutex which would be an inversion wrt. the 5312 * normal lock order. 5313 * 5314 * However we can safely take this lock because its the child 5315 * ctx->mutex. 5316 */ 5317 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING); 5318 5319 /* 5320 * We have to re-check the event->owner field, if it is cleared 5321 * we raced with perf_event_exit_task(), acquiring the mutex 5322 * ensured they're done, and we can proceed with freeing the 5323 * event. 5324 */ 5325 if (event->owner) { 5326 list_del_init(&event->owner_entry); 5327 smp_store_release(&event->owner, NULL); 5328 } 5329 mutex_unlock(&owner->perf_event_mutex); 5330 put_task_struct(owner); 5331 } 5332 } 5333 5334 static void put_event(struct perf_event *event) 5335 { 5336 if (!atomic_long_dec_and_test(&event->refcount)) 5337 return; 5338 5339 _free_event(event); 5340 } 5341 5342 /* 5343 * Kill an event dead; while event:refcount will preserve the event 5344 * object, it will not preserve its functionality. Once the last 'user' 5345 * gives up the object, we'll destroy the thing. 5346 */ 5347 int perf_event_release_kernel(struct perf_event *event) 5348 { 5349 struct perf_event_context *ctx = event->ctx; 5350 struct perf_event *child, *tmp; 5351 LIST_HEAD(free_list); 5352 5353 /* 5354 * If we got here through err_alloc: free_event(event); we will not 5355 * have attached to a context yet. 5356 */ 5357 if (!ctx) { 5358 WARN_ON_ONCE(event->attach_state & 5359 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP)); 5360 goto no_ctx; 5361 } 5362 5363 if (!is_kernel_event(event)) 5364 perf_remove_from_owner(event); 5365 5366 ctx = perf_event_ctx_lock(event); 5367 WARN_ON_ONCE(ctx->parent_ctx); 5368 5369 /* 5370 * Mark this event as STATE_DEAD, there is no external reference to it 5371 * anymore. 5372 * 5373 * Anybody acquiring event->child_mutex after the below loop _must_ 5374 * also see this, most importantly inherit_event() which will avoid 5375 * placing more children on the list. 5376 * 5377 * Thus this guarantees that we will in fact observe and kill _ALL_ 5378 * child events. 5379 */ 5380 perf_remove_from_context(event, DETACH_GROUP|DETACH_DEAD); 5381 5382 perf_event_ctx_unlock(event, ctx); 5383 5384 again: 5385 mutex_lock(&event->child_mutex); 5386 list_for_each_entry(child, &event->child_list, child_list) { 5387 5388 /* 5389 * Cannot change, child events are not migrated, see the 5390 * comment with perf_event_ctx_lock_nested(). 5391 */ 5392 ctx = READ_ONCE(child->ctx); 5393 /* 5394 * Since child_mutex nests inside ctx::mutex, we must jump 5395 * through hoops. We start by grabbing a reference on the ctx. 5396 * 5397 * Since the event cannot get freed while we hold the 5398 * child_mutex, the context must also exist and have a !0 5399 * reference count. 5400 */ 5401 get_ctx(ctx); 5402 5403 /* 5404 * Now that we have a ctx ref, we can drop child_mutex, and 5405 * acquire ctx::mutex without fear of it going away. Then we 5406 * can re-acquire child_mutex. 5407 */ 5408 mutex_unlock(&event->child_mutex); 5409 mutex_lock(&ctx->mutex); 5410 mutex_lock(&event->child_mutex); 5411 5412 /* 5413 * Now that we hold ctx::mutex and child_mutex, revalidate our 5414 * state, if child is still the first entry, it didn't get freed 5415 * and we can continue doing so. 5416 */ 5417 tmp = list_first_entry_or_null(&event->child_list, 5418 struct perf_event, child_list); 5419 if (tmp == child) { 5420 perf_remove_from_context(child, DETACH_GROUP); 5421 list_move(&child->child_list, &free_list); 5422 /* 5423 * This matches the refcount bump in inherit_event(); 5424 * this can't be the last reference. 5425 */ 5426 put_event(event); 5427 } 5428 5429 mutex_unlock(&event->child_mutex); 5430 mutex_unlock(&ctx->mutex); 5431 put_ctx(ctx); 5432 goto again; 5433 } 5434 mutex_unlock(&event->child_mutex); 5435 5436 list_for_each_entry_safe(child, tmp, &free_list, child_list) { 5437 void *var = &child->ctx->refcount; 5438 5439 list_del(&child->child_list); 5440 free_event(child); 5441 5442 /* 5443 * Wake any perf_event_free_task() waiting for this event to be 5444 * freed. 5445 */ 5446 smp_mb(); /* pairs with wait_var_event() */ 5447 wake_up_var(var); 5448 } 5449 5450 no_ctx: 5451 put_event(event); /* Must be the 'last' reference */ 5452 return 0; 5453 } 5454 EXPORT_SYMBOL_GPL(perf_event_release_kernel); 5455 5456 /* 5457 * Called when the last reference to the file is gone. 5458 */ 5459 static int perf_release(struct inode *inode, struct file *file) 5460 { 5461 perf_event_release_kernel(file->private_data); 5462 return 0; 5463 } 5464 5465 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) 5466 { 5467 struct perf_event *child; 5468 u64 total = 0; 5469 5470 *enabled = 0; 5471 *running = 0; 5472 5473 mutex_lock(&event->child_mutex); 5474 5475 (void)perf_event_read(event, false); 5476 total += perf_event_count(event); 5477 5478 *enabled += event->total_time_enabled + 5479 atomic64_read(&event->child_total_time_enabled); 5480 *running += event->total_time_running + 5481 atomic64_read(&event->child_total_time_running); 5482 5483 list_for_each_entry(child, &event->child_list, child_list) { 5484 (void)perf_event_read(child, false); 5485 total += perf_event_count(child); 5486 *enabled += child->total_time_enabled; 5487 *running += child->total_time_running; 5488 } 5489 mutex_unlock(&event->child_mutex); 5490 5491 return total; 5492 } 5493 5494 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) 5495 { 5496 struct perf_event_context *ctx; 5497 u64 count; 5498 5499 ctx = perf_event_ctx_lock(event); 5500 count = __perf_event_read_value(event, enabled, running); 5501 perf_event_ctx_unlock(event, ctx); 5502 5503 return count; 5504 } 5505 EXPORT_SYMBOL_GPL(perf_event_read_value); 5506 5507 static int __perf_read_group_add(struct perf_event *leader, 5508 u64 read_format, u64 *values) 5509 { 5510 struct perf_event_context *ctx = leader->ctx; 5511 struct perf_event *sub, *parent; 5512 unsigned long flags; 5513 int n = 1; /* skip @nr */ 5514 int ret; 5515 5516 ret = perf_event_read(leader, true); 5517 if (ret) 5518 return ret; 5519 5520 raw_spin_lock_irqsave(&ctx->lock, flags); 5521 /* 5522 * Verify the grouping between the parent and child (inherited) 5523 * events is still in tact. 5524 * 5525 * Specifically: 5526 * - leader->ctx->lock pins leader->sibling_list 5527 * - parent->child_mutex pins parent->child_list 5528 * - parent->ctx->mutex pins parent->sibling_list 5529 * 5530 * Because parent->ctx != leader->ctx (and child_list nests inside 5531 * ctx->mutex), group destruction is not atomic between children, also 5532 * see perf_event_release_kernel(). Additionally, parent can grow the 5533 * group. 5534 * 5535 * Therefore it is possible to have parent and child groups in a 5536 * different configuration and summing over such a beast makes no sense 5537 * what so ever. 5538 * 5539 * Reject this. 5540 */ 5541 parent = leader->parent; 5542 if (parent && 5543 (parent->group_generation != leader->group_generation || 5544 parent->nr_siblings != leader->nr_siblings)) { 5545 ret = -ECHILD; 5546 goto unlock; 5547 } 5548 5549 /* 5550 * Since we co-schedule groups, {enabled,running} times of siblings 5551 * will be identical to those of the leader, so we only publish one 5552 * set. 5553 */ 5554 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { 5555 values[n++] += leader->total_time_enabled + 5556 atomic64_read(&leader->child_total_time_enabled); 5557 } 5558 5559 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { 5560 values[n++] += leader->total_time_running + 5561 atomic64_read(&leader->child_total_time_running); 5562 } 5563 5564 /* 5565 * Write {count,id} tuples for every sibling. 5566 */ 5567 values[n++] += perf_event_count(leader); 5568 if (read_format & PERF_FORMAT_ID) 5569 values[n++] = primary_event_id(leader); 5570 if (read_format & PERF_FORMAT_LOST) 5571 values[n++] = atomic64_read(&leader->lost_samples); 5572 5573 for_each_sibling_event(sub, leader) { 5574 values[n++] += perf_event_count(sub); 5575 if (read_format & PERF_FORMAT_ID) 5576 values[n++] = primary_event_id(sub); 5577 if (read_format & PERF_FORMAT_LOST) 5578 values[n++] = atomic64_read(&sub->lost_samples); 5579 } 5580 5581 unlock: 5582 raw_spin_unlock_irqrestore(&ctx->lock, flags); 5583 return ret; 5584 } 5585 5586 static int perf_read_group(struct perf_event *event, 5587 u64 read_format, char __user *buf) 5588 { 5589 struct perf_event *leader = event->group_leader, *child; 5590 struct perf_event_context *ctx = leader->ctx; 5591 int ret; 5592 u64 *values; 5593 5594 lockdep_assert_held(&ctx->mutex); 5595 5596 values = kzalloc(event->read_size, GFP_KERNEL); 5597 if (!values) 5598 return -ENOMEM; 5599 5600 values[0] = 1 + leader->nr_siblings; 5601 5602 mutex_lock(&leader->child_mutex); 5603 5604 ret = __perf_read_group_add(leader, read_format, values); 5605 if (ret) 5606 goto unlock; 5607 5608 list_for_each_entry(child, &leader->child_list, child_list) { 5609 ret = __perf_read_group_add(child, read_format, values); 5610 if (ret) 5611 goto unlock; 5612 } 5613 5614 mutex_unlock(&leader->child_mutex); 5615 5616 ret = event->read_size; 5617 if (copy_to_user(buf, values, event->read_size)) 5618 ret = -EFAULT; 5619 goto out; 5620 5621 unlock: 5622 mutex_unlock(&leader->child_mutex); 5623 out: 5624 kfree(values); 5625 return ret; 5626 } 5627 5628 static int perf_read_one(struct perf_event *event, 5629 u64 read_format, char __user *buf) 5630 { 5631 u64 enabled, running; 5632 u64 values[5]; 5633 int n = 0; 5634 5635 values[n++] = __perf_event_read_value(event, &enabled, &running); 5636 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 5637 values[n++] = enabled; 5638 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 5639 values[n++] = running; 5640 if (read_format & PERF_FORMAT_ID) 5641 values[n++] = primary_event_id(event); 5642 if (read_format & PERF_FORMAT_LOST) 5643 values[n++] = atomic64_read(&event->lost_samples); 5644 5645 if (copy_to_user(buf, values, n * sizeof(u64))) 5646 return -EFAULT; 5647 5648 return n * sizeof(u64); 5649 } 5650 5651 static bool is_event_hup(struct perf_event *event) 5652 { 5653 bool no_children; 5654 5655 if (event->state > PERF_EVENT_STATE_EXIT) 5656 return false; 5657 5658 mutex_lock(&event->child_mutex); 5659 no_children = list_empty(&event->child_list); 5660 mutex_unlock(&event->child_mutex); 5661 return no_children; 5662 } 5663 5664 /* 5665 * Read the performance event - simple non blocking version for now 5666 */ 5667 static ssize_t 5668 __perf_read(struct perf_event *event, char __user *buf, size_t count) 5669 { 5670 u64 read_format = event->attr.read_format; 5671 int ret; 5672 5673 /* 5674 * Return end-of-file for a read on an event that is in 5675 * error state (i.e. because it was pinned but it couldn't be 5676 * scheduled on to the CPU at some point). 5677 */ 5678 if (event->state == PERF_EVENT_STATE_ERROR) 5679 return 0; 5680 5681 if (count < event->read_size) 5682 return -ENOSPC; 5683 5684 WARN_ON_ONCE(event->ctx->parent_ctx); 5685 if (read_format & PERF_FORMAT_GROUP) 5686 ret = perf_read_group(event, read_format, buf); 5687 else 5688 ret = perf_read_one(event, read_format, buf); 5689 5690 return ret; 5691 } 5692 5693 static ssize_t 5694 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 5695 { 5696 struct perf_event *event = file->private_data; 5697 struct perf_event_context *ctx; 5698 int ret; 5699 5700 ret = security_perf_event_read(event); 5701 if (ret) 5702 return ret; 5703 5704 ctx = perf_event_ctx_lock(event); 5705 ret = __perf_read(event, buf, count); 5706 perf_event_ctx_unlock(event, ctx); 5707 5708 return ret; 5709 } 5710 5711 static __poll_t perf_poll(struct file *file, poll_table *wait) 5712 { 5713 struct perf_event *event = file->private_data; 5714 struct perf_buffer *rb; 5715 __poll_t events = EPOLLHUP; 5716 5717 poll_wait(file, &event->waitq, wait); 5718 5719 if (is_event_hup(event)) 5720 return events; 5721 5722 /* 5723 * Pin the event->rb by taking event->mmap_mutex; otherwise 5724 * perf_event_set_output() can swizzle our rb and make us miss wakeups. 5725 */ 5726 mutex_lock(&event->mmap_mutex); 5727 rb = event->rb; 5728 if (rb) 5729 events = atomic_xchg(&rb->poll, 0); 5730 mutex_unlock(&event->mmap_mutex); 5731 return events; 5732 } 5733 5734 static void _perf_event_reset(struct perf_event *event) 5735 { 5736 (void)perf_event_read(event, false); 5737 local64_set(&event->count, 0); 5738 perf_event_update_userpage(event); 5739 } 5740 5741 /* Assume it's not an event with inherit set. */ 5742 u64 perf_event_pause(struct perf_event *event, bool reset) 5743 { 5744 struct perf_event_context *ctx; 5745 u64 count; 5746 5747 ctx = perf_event_ctx_lock(event); 5748 WARN_ON_ONCE(event->attr.inherit); 5749 _perf_event_disable(event); 5750 count = local64_read(&event->count); 5751 if (reset) 5752 local64_set(&event->count, 0); 5753 perf_event_ctx_unlock(event, ctx); 5754 5755 return count; 5756 } 5757 EXPORT_SYMBOL_GPL(perf_event_pause); 5758 5759 /* 5760 * Holding the top-level event's child_mutex means that any 5761 * descendant process that has inherited this event will block 5762 * in perf_event_exit_event() if it goes to exit, thus satisfying the 5763 * task existence requirements of perf_event_enable/disable. 5764 */ 5765 static void perf_event_for_each_child(struct perf_event *event, 5766 void (*func)(struct perf_event *)) 5767 { 5768 struct perf_event *child; 5769 5770 WARN_ON_ONCE(event->ctx->parent_ctx); 5771 5772 mutex_lock(&event->child_mutex); 5773 func(event); 5774 list_for_each_entry(child, &event->child_list, child_list) 5775 func(child); 5776 mutex_unlock(&event->child_mutex); 5777 } 5778 5779 static void perf_event_for_each(struct perf_event *event, 5780 void (*func)(struct perf_event *)) 5781 { 5782 struct perf_event_context *ctx = event->ctx; 5783 struct perf_event *sibling; 5784 5785 lockdep_assert_held(&ctx->mutex); 5786 5787 event = event->group_leader; 5788 5789 perf_event_for_each_child(event, func); 5790 for_each_sibling_event(sibling, event) 5791 perf_event_for_each_child(sibling, func); 5792 } 5793 5794 static void __perf_event_period(struct perf_event *event, 5795 struct perf_cpu_context *cpuctx, 5796 struct perf_event_context *ctx, 5797 void *info) 5798 { 5799 u64 value = *((u64 *)info); 5800 bool active; 5801 5802 if (event->attr.freq) { 5803 event->attr.sample_freq = value; 5804 } else { 5805 event->attr.sample_period = value; 5806 event->hw.sample_period = value; 5807 } 5808 5809 active = (event->state == PERF_EVENT_STATE_ACTIVE); 5810 if (active) { 5811 perf_pmu_disable(event->pmu); 5812 /* 5813 * We could be throttled; unthrottle now to avoid the tick 5814 * trying to unthrottle while we already re-started the event. 5815 */ 5816 if (event->hw.interrupts == MAX_INTERRUPTS) { 5817 event->hw.interrupts = 0; 5818 perf_log_throttle(event, 1); 5819 } 5820 event->pmu->stop(event, PERF_EF_UPDATE); 5821 } 5822 5823 local64_set(&event->hw.period_left, 0); 5824 5825 if (active) { 5826 event->pmu->start(event, PERF_EF_RELOAD); 5827 perf_pmu_enable(event->pmu); 5828 } 5829 } 5830 5831 static int perf_event_check_period(struct perf_event *event, u64 value) 5832 { 5833 return event->pmu->check_period(event, value); 5834 } 5835 5836 static int _perf_event_period(struct perf_event *event, u64 value) 5837 { 5838 if (!is_sampling_event(event)) 5839 return -EINVAL; 5840 5841 if (!value) 5842 return -EINVAL; 5843 5844 if (event->attr.freq && value > sysctl_perf_event_sample_rate) 5845 return -EINVAL; 5846 5847 if (perf_event_check_period(event, value)) 5848 return -EINVAL; 5849 5850 if (!event->attr.freq && (value & (1ULL << 63))) 5851 return -EINVAL; 5852 5853 event_function_call(event, __perf_event_period, &value); 5854 5855 return 0; 5856 } 5857 5858 int perf_event_period(struct perf_event *event, u64 value) 5859 { 5860 struct perf_event_context *ctx; 5861 int ret; 5862 5863 ctx = perf_event_ctx_lock(event); 5864 ret = _perf_event_period(event, value); 5865 perf_event_ctx_unlock(event, ctx); 5866 5867 return ret; 5868 } 5869 EXPORT_SYMBOL_GPL(perf_event_period); 5870 5871 static const struct file_operations perf_fops; 5872 5873 static inline int perf_fget_light(int fd, struct fd *p) 5874 { 5875 struct fd f = fdget(fd); 5876 if (!f.file) 5877 return -EBADF; 5878 5879 if (f.file->f_op != &perf_fops) { 5880 fdput(f); 5881 return -EBADF; 5882 } 5883 *p = f; 5884 return 0; 5885 } 5886 5887 static int perf_event_set_output(struct perf_event *event, 5888 struct perf_event *output_event); 5889 static int perf_event_set_filter(struct perf_event *event, void __user *arg); 5890 static int perf_copy_attr(struct perf_event_attr __user *uattr, 5891 struct perf_event_attr *attr); 5892 5893 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg) 5894 { 5895 void (*func)(struct perf_event *); 5896 u32 flags = arg; 5897 5898 switch (cmd) { 5899 case PERF_EVENT_IOC_ENABLE: 5900 func = _perf_event_enable; 5901 break; 5902 case PERF_EVENT_IOC_DISABLE: 5903 func = _perf_event_disable; 5904 break; 5905 case PERF_EVENT_IOC_RESET: 5906 func = _perf_event_reset; 5907 break; 5908 5909 case PERF_EVENT_IOC_REFRESH: 5910 return _perf_event_refresh(event, arg); 5911 5912 case PERF_EVENT_IOC_PERIOD: 5913 { 5914 u64 value; 5915 5916 if (copy_from_user(&value, (u64 __user *)arg, sizeof(value))) 5917 return -EFAULT; 5918 5919 return _perf_event_period(event, value); 5920 } 5921 case PERF_EVENT_IOC_ID: 5922 { 5923 u64 id = primary_event_id(event); 5924 5925 if (copy_to_user((void __user *)arg, &id, sizeof(id))) 5926 return -EFAULT; 5927 return 0; 5928 } 5929 5930 case PERF_EVENT_IOC_SET_OUTPUT: 5931 { 5932 int ret; 5933 if (arg != -1) { 5934 struct perf_event *output_event; 5935 struct fd output; 5936 ret = perf_fget_light(arg, &output); 5937 if (ret) 5938 return ret; 5939 output_event = output.file->private_data; 5940 ret = perf_event_set_output(event, output_event); 5941 fdput(output); 5942 } else { 5943 ret = perf_event_set_output(event, NULL); 5944 } 5945 return ret; 5946 } 5947 5948 case PERF_EVENT_IOC_SET_FILTER: 5949 return perf_event_set_filter(event, (void __user *)arg); 5950 5951 case PERF_EVENT_IOC_SET_BPF: 5952 { 5953 struct bpf_prog *prog; 5954 int err; 5955 5956 prog = bpf_prog_get(arg); 5957 if (IS_ERR(prog)) 5958 return PTR_ERR(prog); 5959 5960 err = perf_event_set_bpf_prog(event, prog, 0); 5961 if (err) { 5962 bpf_prog_put(prog); 5963 return err; 5964 } 5965 5966 return 0; 5967 } 5968 5969 case PERF_EVENT_IOC_PAUSE_OUTPUT: { 5970 struct perf_buffer *rb; 5971 5972 rcu_read_lock(); 5973 rb = rcu_dereference(event->rb); 5974 if (!rb || !rb->nr_pages) { 5975 rcu_read_unlock(); 5976 return -EINVAL; 5977 } 5978 rb_toggle_paused(rb, !!arg); 5979 rcu_read_unlock(); 5980 return 0; 5981 } 5982 5983 case PERF_EVENT_IOC_QUERY_BPF: 5984 return perf_event_query_prog_array(event, (void __user *)arg); 5985 5986 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: { 5987 struct perf_event_attr new_attr; 5988 int err = perf_copy_attr((struct perf_event_attr __user *)arg, 5989 &new_attr); 5990 5991 if (err) 5992 return err; 5993 5994 return perf_event_modify_attr(event, &new_attr); 5995 } 5996 default: 5997 return -ENOTTY; 5998 } 5999 6000 if (flags & PERF_IOC_FLAG_GROUP) 6001 perf_event_for_each(event, func); 6002 else 6003 perf_event_for_each_child(event, func); 6004 6005 return 0; 6006 } 6007 6008 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 6009 { 6010 struct perf_event *event = file->private_data; 6011 struct perf_event_context *ctx; 6012 long ret; 6013 6014 /* Treat ioctl like writes as it is likely a mutating operation. */ 6015 ret = security_perf_event_write(event); 6016 if (ret) 6017 return ret; 6018 6019 ctx = perf_event_ctx_lock(event); 6020 ret = _perf_ioctl(event, cmd, arg); 6021 perf_event_ctx_unlock(event, ctx); 6022 6023 return ret; 6024 } 6025 6026 #ifdef CONFIG_COMPAT 6027 static long perf_compat_ioctl(struct file *file, unsigned int cmd, 6028 unsigned long arg) 6029 { 6030 switch (_IOC_NR(cmd)) { 6031 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER): 6032 case _IOC_NR(PERF_EVENT_IOC_ID): 6033 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF): 6034 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES): 6035 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */ 6036 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) { 6037 cmd &= ~IOCSIZE_MASK; 6038 cmd |= sizeof(void *) << IOCSIZE_SHIFT; 6039 } 6040 break; 6041 } 6042 return perf_ioctl(file, cmd, arg); 6043 } 6044 #else 6045 # define perf_compat_ioctl NULL 6046 #endif 6047 6048 int perf_event_task_enable(void) 6049 { 6050 struct perf_event_context *ctx; 6051 struct perf_event *event; 6052 6053 mutex_lock(¤t->perf_event_mutex); 6054 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { 6055 ctx = perf_event_ctx_lock(event); 6056 perf_event_for_each_child(event, _perf_event_enable); 6057 perf_event_ctx_unlock(event, ctx); 6058 } 6059 mutex_unlock(¤t->perf_event_mutex); 6060 6061 return 0; 6062 } 6063 6064 int perf_event_task_disable(void) 6065 { 6066 struct perf_event_context *ctx; 6067 struct perf_event *event; 6068 6069 mutex_lock(¤t->perf_event_mutex); 6070 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { 6071 ctx = perf_event_ctx_lock(event); 6072 perf_event_for_each_child(event, _perf_event_disable); 6073 perf_event_ctx_unlock(event, ctx); 6074 } 6075 mutex_unlock(¤t->perf_event_mutex); 6076 6077 return 0; 6078 } 6079 6080 static int perf_event_index(struct perf_event *event) 6081 { 6082 if (event->hw.state & PERF_HES_STOPPED) 6083 return 0; 6084 6085 if (event->state != PERF_EVENT_STATE_ACTIVE) 6086 return 0; 6087 6088 return event->pmu->event_idx(event); 6089 } 6090 6091 static void perf_event_init_userpage(struct perf_event *event) 6092 { 6093 struct perf_event_mmap_page *userpg; 6094 struct perf_buffer *rb; 6095 6096 rcu_read_lock(); 6097 rb = rcu_dereference(event->rb); 6098 if (!rb) 6099 goto unlock; 6100 6101 userpg = rb->user_page; 6102 6103 /* Allow new userspace to detect that bit 0 is deprecated */ 6104 userpg->cap_bit0_is_deprecated = 1; 6105 userpg->size = offsetof(struct perf_event_mmap_page, __reserved); 6106 userpg->data_offset = PAGE_SIZE; 6107 userpg->data_size = perf_data_size(rb); 6108 6109 unlock: 6110 rcu_read_unlock(); 6111 } 6112 6113 void __weak arch_perf_update_userpage( 6114 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now) 6115 { 6116 } 6117 6118 /* 6119 * Callers need to ensure there can be no nesting of this function, otherwise 6120 * the seqlock logic goes bad. We can not serialize this because the arch 6121 * code calls this from NMI context. 6122 */ 6123 void perf_event_update_userpage(struct perf_event *event) 6124 { 6125 struct perf_event_mmap_page *userpg; 6126 struct perf_buffer *rb; 6127 u64 enabled, running, now; 6128 6129 rcu_read_lock(); 6130 rb = rcu_dereference(event->rb); 6131 if (!rb) 6132 goto unlock; 6133 6134 /* 6135 * compute total_time_enabled, total_time_running 6136 * based on snapshot values taken when the event 6137 * was last scheduled in. 6138 * 6139 * we cannot simply called update_context_time() 6140 * because of locking issue as we can be called in 6141 * NMI context 6142 */ 6143 calc_timer_values(event, &now, &enabled, &running); 6144 6145 userpg = rb->user_page; 6146 /* 6147 * Disable preemption to guarantee consistent time stamps are stored to 6148 * the user page. 6149 */ 6150 preempt_disable(); 6151 ++userpg->lock; 6152 barrier(); 6153 userpg->index = perf_event_index(event); 6154 userpg->offset = perf_event_count(event); 6155 if (userpg->index) 6156 userpg->offset -= local64_read(&event->hw.prev_count); 6157 6158 userpg->time_enabled = enabled + 6159 atomic64_read(&event->child_total_time_enabled); 6160 6161 userpg->time_running = running + 6162 atomic64_read(&event->child_total_time_running); 6163 6164 arch_perf_update_userpage(event, userpg, now); 6165 6166 barrier(); 6167 ++userpg->lock; 6168 preempt_enable(); 6169 unlock: 6170 rcu_read_unlock(); 6171 } 6172 EXPORT_SYMBOL_GPL(perf_event_update_userpage); 6173 6174 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf) 6175 { 6176 struct perf_event *event = vmf->vma->vm_file->private_data; 6177 struct perf_buffer *rb; 6178 vm_fault_t ret = VM_FAULT_SIGBUS; 6179 6180 if (vmf->flags & FAULT_FLAG_MKWRITE) { 6181 if (vmf->pgoff == 0) 6182 ret = 0; 6183 return ret; 6184 } 6185 6186 rcu_read_lock(); 6187 rb = rcu_dereference(event->rb); 6188 if (!rb) 6189 goto unlock; 6190 6191 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE)) 6192 goto unlock; 6193 6194 vmf->page = perf_mmap_to_page(rb, vmf->pgoff); 6195 if (!vmf->page) 6196 goto unlock; 6197 6198 get_page(vmf->page); 6199 vmf->page->mapping = vmf->vma->vm_file->f_mapping; 6200 vmf->page->index = vmf->pgoff; 6201 6202 ret = 0; 6203 unlock: 6204 rcu_read_unlock(); 6205 6206 return ret; 6207 } 6208 6209 static void ring_buffer_attach(struct perf_event *event, 6210 struct perf_buffer *rb) 6211 { 6212 struct perf_buffer *old_rb = NULL; 6213 unsigned long flags; 6214 6215 WARN_ON_ONCE(event->parent); 6216 6217 if (event->rb) { 6218 /* 6219 * Should be impossible, we set this when removing 6220 * event->rb_entry and wait/clear when adding event->rb_entry. 6221 */ 6222 WARN_ON_ONCE(event->rcu_pending); 6223 6224 old_rb = event->rb; 6225 spin_lock_irqsave(&old_rb->event_lock, flags); 6226 list_del_rcu(&event->rb_entry); 6227 spin_unlock_irqrestore(&old_rb->event_lock, flags); 6228 6229 event->rcu_batches = get_state_synchronize_rcu(); 6230 event->rcu_pending = 1; 6231 } 6232 6233 if (rb) { 6234 if (event->rcu_pending) { 6235 cond_synchronize_rcu(event->rcu_batches); 6236 event->rcu_pending = 0; 6237 } 6238 6239 spin_lock_irqsave(&rb->event_lock, flags); 6240 list_add_rcu(&event->rb_entry, &rb->event_list); 6241 spin_unlock_irqrestore(&rb->event_lock, flags); 6242 } 6243 6244 /* 6245 * Avoid racing with perf_mmap_close(AUX): stop the event 6246 * before swizzling the event::rb pointer; if it's getting 6247 * unmapped, its aux_mmap_count will be 0 and it won't 6248 * restart. See the comment in __perf_pmu_output_stop(). 6249 * 6250 * Data will inevitably be lost when set_output is done in 6251 * mid-air, but then again, whoever does it like this is 6252 * not in for the data anyway. 6253 */ 6254 if (has_aux(event)) 6255 perf_event_stop(event, 0); 6256 6257 rcu_assign_pointer(event->rb, rb); 6258 6259 if (old_rb) { 6260 ring_buffer_put(old_rb); 6261 /* 6262 * Since we detached before setting the new rb, so that we 6263 * could attach the new rb, we could have missed a wakeup. 6264 * Provide it now. 6265 */ 6266 wake_up_all(&event->waitq); 6267 } 6268 } 6269 6270 static void ring_buffer_wakeup(struct perf_event *event) 6271 { 6272 struct perf_buffer *rb; 6273 6274 if (event->parent) 6275 event = event->parent; 6276 6277 rcu_read_lock(); 6278 rb = rcu_dereference(event->rb); 6279 if (rb) { 6280 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) 6281 wake_up_all(&event->waitq); 6282 } 6283 rcu_read_unlock(); 6284 } 6285 6286 struct perf_buffer *ring_buffer_get(struct perf_event *event) 6287 { 6288 struct perf_buffer *rb; 6289 6290 if (event->parent) 6291 event = event->parent; 6292 6293 rcu_read_lock(); 6294 rb = rcu_dereference(event->rb); 6295 if (rb) { 6296 if (!refcount_inc_not_zero(&rb->refcount)) 6297 rb = NULL; 6298 } 6299 rcu_read_unlock(); 6300 6301 return rb; 6302 } 6303 6304 void ring_buffer_put(struct perf_buffer *rb) 6305 { 6306 if (!refcount_dec_and_test(&rb->refcount)) 6307 return; 6308 6309 WARN_ON_ONCE(!list_empty(&rb->event_list)); 6310 6311 call_rcu(&rb->rcu_head, rb_free_rcu); 6312 } 6313 6314 static void perf_mmap_open(struct vm_area_struct *vma) 6315 { 6316 struct perf_event *event = vma->vm_file->private_data; 6317 6318 atomic_inc(&event->mmap_count); 6319 atomic_inc(&event->rb->mmap_count); 6320 6321 if (vma->vm_pgoff) 6322 atomic_inc(&event->rb->aux_mmap_count); 6323 6324 if (event->pmu->event_mapped) 6325 event->pmu->event_mapped(event, vma->vm_mm); 6326 } 6327 6328 static void perf_pmu_output_stop(struct perf_event *event); 6329 6330 /* 6331 * A buffer can be mmap()ed multiple times; either directly through the same 6332 * event, or through other events by use of perf_event_set_output(). 6333 * 6334 * In order to undo the VM accounting done by perf_mmap() we need to destroy 6335 * the buffer here, where we still have a VM context. This means we need 6336 * to detach all events redirecting to us. 6337 */ 6338 static void perf_mmap_close(struct vm_area_struct *vma) 6339 { 6340 struct perf_event *event = vma->vm_file->private_data; 6341 struct perf_buffer *rb = ring_buffer_get(event); 6342 struct user_struct *mmap_user = rb->mmap_user; 6343 int mmap_locked = rb->mmap_locked; 6344 unsigned long size = perf_data_size(rb); 6345 bool detach_rest = false; 6346 6347 if (event->pmu->event_unmapped) 6348 event->pmu->event_unmapped(event, vma->vm_mm); 6349 6350 /* 6351 * rb->aux_mmap_count will always drop before rb->mmap_count and 6352 * event->mmap_count, so it is ok to use event->mmap_mutex to 6353 * serialize with perf_mmap here. 6354 */ 6355 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff && 6356 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) { 6357 /* 6358 * Stop all AUX events that are writing to this buffer, 6359 * so that we can free its AUX pages and corresponding PMU 6360 * data. Note that after rb::aux_mmap_count dropped to zero, 6361 * they won't start any more (see perf_aux_output_begin()). 6362 */ 6363 perf_pmu_output_stop(event); 6364 6365 /* now it's safe to free the pages */ 6366 atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm); 6367 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm); 6368 6369 /* this has to be the last one */ 6370 rb_free_aux(rb); 6371 WARN_ON_ONCE(refcount_read(&rb->aux_refcount)); 6372 6373 mutex_unlock(&event->mmap_mutex); 6374 } 6375 6376 if (atomic_dec_and_test(&rb->mmap_count)) 6377 detach_rest = true; 6378 6379 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) 6380 goto out_put; 6381 6382 ring_buffer_attach(event, NULL); 6383 mutex_unlock(&event->mmap_mutex); 6384 6385 /* If there's still other mmap()s of this buffer, we're done. */ 6386 if (!detach_rest) 6387 goto out_put; 6388 6389 /* 6390 * No other mmap()s, detach from all other events that might redirect 6391 * into the now unreachable buffer. Somewhat complicated by the 6392 * fact that rb::event_lock otherwise nests inside mmap_mutex. 6393 */ 6394 again: 6395 rcu_read_lock(); 6396 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) { 6397 if (!atomic_long_inc_not_zero(&event->refcount)) { 6398 /* 6399 * This event is en-route to free_event() which will 6400 * detach it and remove it from the list. 6401 */ 6402 continue; 6403 } 6404 rcu_read_unlock(); 6405 6406 mutex_lock(&event->mmap_mutex); 6407 /* 6408 * Check we didn't race with perf_event_set_output() which can 6409 * swizzle the rb from under us while we were waiting to 6410 * acquire mmap_mutex. 6411 * 6412 * If we find a different rb; ignore this event, a next 6413 * iteration will no longer find it on the list. We have to 6414 * still restart the iteration to make sure we're not now 6415 * iterating the wrong list. 6416 */ 6417 if (event->rb == rb) 6418 ring_buffer_attach(event, NULL); 6419 6420 mutex_unlock(&event->mmap_mutex); 6421 put_event(event); 6422 6423 /* 6424 * Restart the iteration; either we're on the wrong list or 6425 * destroyed its integrity by doing a deletion. 6426 */ 6427 goto again; 6428 } 6429 rcu_read_unlock(); 6430 6431 /* 6432 * It could be there's still a few 0-ref events on the list; they'll 6433 * get cleaned up by free_event() -- they'll also still have their 6434 * ref on the rb and will free it whenever they are done with it. 6435 * 6436 * Aside from that, this buffer is 'fully' detached and unmapped, 6437 * undo the VM accounting. 6438 */ 6439 6440 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked, 6441 &mmap_user->locked_vm); 6442 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm); 6443 free_uid(mmap_user); 6444 6445 out_put: 6446 ring_buffer_put(rb); /* could be last */ 6447 } 6448 6449 static const struct vm_operations_struct perf_mmap_vmops = { 6450 .open = perf_mmap_open, 6451 .close = perf_mmap_close, /* non mergeable */ 6452 .fault = perf_mmap_fault, 6453 .page_mkwrite = perf_mmap_fault, 6454 }; 6455 6456 static int perf_mmap(struct file *file, struct vm_area_struct *vma) 6457 { 6458 struct perf_event *event = file->private_data; 6459 unsigned long user_locked, user_lock_limit; 6460 struct user_struct *user = current_user(); 6461 struct perf_buffer *rb = NULL; 6462 unsigned long locked, lock_limit; 6463 unsigned long vma_size; 6464 unsigned long nr_pages; 6465 long user_extra = 0, extra = 0; 6466 int ret = 0, flags = 0; 6467 6468 /* 6469 * Don't allow mmap() of inherited per-task counters. This would 6470 * create a performance issue due to all children writing to the 6471 * same rb. 6472 */ 6473 if (event->cpu == -1 && event->attr.inherit) 6474 return -EINVAL; 6475 6476 if (!(vma->vm_flags & VM_SHARED)) 6477 return -EINVAL; 6478 6479 ret = security_perf_event_read(event); 6480 if (ret) 6481 return ret; 6482 6483 vma_size = vma->vm_end - vma->vm_start; 6484 6485 if (vma->vm_pgoff == 0) { 6486 nr_pages = (vma_size / PAGE_SIZE) - 1; 6487 } else { 6488 /* 6489 * AUX area mapping: if rb->aux_nr_pages != 0, it's already 6490 * mapped, all subsequent mappings should have the same size 6491 * and offset. Must be above the normal perf buffer. 6492 */ 6493 u64 aux_offset, aux_size; 6494 6495 if (!event->rb) 6496 return -EINVAL; 6497 6498 nr_pages = vma_size / PAGE_SIZE; 6499 6500 mutex_lock(&event->mmap_mutex); 6501 ret = -EINVAL; 6502 6503 rb = event->rb; 6504 if (!rb) 6505 goto aux_unlock; 6506 6507 aux_offset = READ_ONCE(rb->user_page->aux_offset); 6508 aux_size = READ_ONCE(rb->user_page->aux_size); 6509 6510 if (aux_offset < perf_data_size(rb) + PAGE_SIZE) 6511 goto aux_unlock; 6512 6513 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT) 6514 goto aux_unlock; 6515 6516 /* already mapped with a different offset */ 6517 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff) 6518 goto aux_unlock; 6519 6520 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE) 6521 goto aux_unlock; 6522 6523 /* already mapped with a different size */ 6524 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages) 6525 goto aux_unlock; 6526 6527 if (!is_power_of_2(nr_pages)) 6528 goto aux_unlock; 6529 6530 if (!atomic_inc_not_zero(&rb->mmap_count)) 6531 goto aux_unlock; 6532 6533 if (rb_has_aux(rb)) { 6534 atomic_inc(&rb->aux_mmap_count); 6535 ret = 0; 6536 goto unlock; 6537 } 6538 6539 atomic_set(&rb->aux_mmap_count, 1); 6540 user_extra = nr_pages; 6541 6542 goto accounting; 6543 } 6544 6545 /* 6546 * If we have rb pages ensure they're a power-of-two number, so we 6547 * can do bitmasks instead of modulo. 6548 */ 6549 if (nr_pages != 0 && !is_power_of_2(nr_pages)) 6550 return -EINVAL; 6551 6552 if (vma_size != PAGE_SIZE * (1 + nr_pages)) 6553 return -EINVAL; 6554 6555 WARN_ON_ONCE(event->ctx->parent_ctx); 6556 again: 6557 mutex_lock(&event->mmap_mutex); 6558 if (event->rb) { 6559 if (data_page_nr(event->rb) != nr_pages) { 6560 ret = -EINVAL; 6561 goto unlock; 6562 } 6563 6564 if (!atomic_inc_not_zero(&event->rb->mmap_count)) { 6565 /* 6566 * Raced against perf_mmap_close(); remove the 6567 * event and try again. 6568 */ 6569 ring_buffer_attach(event, NULL); 6570 mutex_unlock(&event->mmap_mutex); 6571 goto again; 6572 } 6573 6574 goto unlock; 6575 } 6576 6577 user_extra = nr_pages + 1; 6578 6579 accounting: 6580 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10); 6581 6582 /* 6583 * Increase the limit linearly with more CPUs: 6584 */ 6585 user_lock_limit *= num_online_cpus(); 6586 6587 user_locked = atomic_long_read(&user->locked_vm); 6588 6589 /* 6590 * sysctl_perf_event_mlock may have changed, so that 6591 * user->locked_vm > user_lock_limit 6592 */ 6593 if (user_locked > user_lock_limit) 6594 user_locked = user_lock_limit; 6595 user_locked += user_extra; 6596 6597 if (user_locked > user_lock_limit) { 6598 /* 6599 * charge locked_vm until it hits user_lock_limit; 6600 * charge the rest from pinned_vm 6601 */ 6602 extra = user_locked - user_lock_limit; 6603 user_extra -= extra; 6604 } 6605 6606 lock_limit = rlimit(RLIMIT_MEMLOCK); 6607 lock_limit >>= PAGE_SHIFT; 6608 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra; 6609 6610 if ((locked > lock_limit) && perf_is_paranoid() && 6611 !capable(CAP_IPC_LOCK)) { 6612 ret = -EPERM; 6613 goto unlock; 6614 } 6615 6616 WARN_ON(!rb && event->rb); 6617 6618 if (vma->vm_flags & VM_WRITE) 6619 flags |= RING_BUFFER_WRITABLE; 6620 6621 if (!rb) { 6622 rb = rb_alloc(nr_pages, 6623 event->attr.watermark ? event->attr.wakeup_watermark : 0, 6624 event->cpu, flags); 6625 6626 if (!rb) { 6627 ret = -ENOMEM; 6628 goto unlock; 6629 } 6630 6631 atomic_set(&rb->mmap_count, 1); 6632 rb->mmap_user = get_current_user(); 6633 rb->mmap_locked = extra; 6634 6635 ring_buffer_attach(event, rb); 6636 6637 perf_event_update_time(event); 6638 perf_event_init_userpage(event); 6639 perf_event_update_userpage(event); 6640 } else { 6641 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages, 6642 event->attr.aux_watermark, flags); 6643 if (!ret) 6644 rb->aux_mmap_locked = extra; 6645 } 6646 6647 unlock: 6648 if (!ret) { 6649 atomic_long_add(user_extra, &user->locked_vm); 6650 atomic64_add(extra, &vma->vm_mm->pinned_vm); 6651 6652 atomic_inc(&event->mmap_count); 6653 } else if (rb) { 6654 atomic_dec(&rb->mmap_count); 6655 } 6656 aux_unlock: 6657 mutex_unlock(&event->mmap_mutex); 6658 6659 /* 6660 * Since pinned accounting is per vm we cannot allow fork() to copy our 6661 * vma. 6662 */ 6663 vm_flags_set(vma, VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP); 6664 vma->vm_ops = &perf_mmap_vmops; 6665 6666 if (event->pmu->event_mapped) 6667 event->pmu->event_mapped(event, vma->vm_mm); 6668 6669 return ret; 6670 } 6671 6672 static int perf_fasync(int fd, struct file *filp, int on) 6673 { 6674 struct inode *inode = file_inode(filp); 6675 struct perf_event *event = filp->private_data; 6676 int retval; 6677 6678 inode_lock(inode); 6679 retval = fasync_helper(fd, filp, on, &event->fasync); 6680 inode_unlock(inode); 6681 6682 if (retval < 0) 6683 return retval; 6684 6685 return 0; 6686 } 6687 6688 static const struct file_operations perf_fops = { 6689 .llseek = no_llseek, 6690 .release = perf_release, 6691 .read = perf_read, 6692 .poll = perf_poll, 6693 .unlocked_ioctl = perf_ioctl, 6694 .compat_ioctl = perf_compat_ioctl, 6695 .mmap = perf_mmap, 6696 .fasync = perf_fasync, 6697 }; 6698 6699 /* 6700 * Perf event wakeup 6701 * 6702 * If there's data, ensure we set the poll() state and publish everything 6703 * to user-space before waking everybody up. 6704 */ 6705 6706 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event) 6707 { 6708 /* only the parent has fasync state */ 6709 if (event->parent) 6710 event = event->parent; 6711 return &event->fasync; 6712 } 6713 6714 void perf_event_wakeup(struct perf_event *event) 6715 { 6716 ring_buffer_wakeup(event); 6717 6718 if (event->pending_kill) { 6719 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill); 6720 event->pending_kill = 0; 6721 } 6722 } 6723 6724 static void perf_sigtrap(struct perf_event *event) 6725 { 6726 /* 6727 * We'd expect this to only occur if the irq_work is delayed and either 6728 * ctx->task or current has changed in the meantime. This can be the 6729 * case on architectures that do not implement arch_irq_work_raise(). 6730 */ 6731 if (WARN_ON_ONCE(event->ctx->task != current)) 6732 return; 6733 6734 /* 6735 * Both perf_pending_task() and perf_pending_irq() can race with the 6736 * task exiting. 6737 */ 6738 if (current->flags & PF_EXITING) 6739 return; 6740 6741 send_sig_perf((void __user *)event->pending_addr, 6742 event->orig_type, event->attr.sig_data); 6743 } 6744 6745 /* 6746 * Deliver the pending work in-event-context or follow the context. 6747 */ 6748 static void __perf_pending_irq(struct perf_event *event) 6749 { 6750 int cpu = READ_ONCE(event->oncpu); 6751 6752 /* 6753 * If the event isn't running; we done. event_sched_out() will have 6754 * taken care of things. 6755 */ 6756 if (cpu < 0) 6757 return; 6758 6759 /* 6760 * Yay, we hit home and are in the context of the event. 6761 */ 6762 if (cpu == smp_processor_id()) { 6763 if (event->pending_sigtrap) { 6764 event->pending_sigtrap = 0; 6765 perf_sigtrap(event); 6766 local_dec(&event->ctx->nr_pending); 6767 } 6768 if (event->pending_disable) { 6769 event->pending_disable = 0; 6770 perf_event_disable_local(event); 6771 } 6772 return; 6773 } 6774 6775 /* 6776 * CPU-A CPU-B 6777 * 6778 * perf_event_disable_inatomic() 6779 * @pending_disable = CPU-A; 6780 * irq_work_queue(); 6781 * 6782 * sched-out 6783 * @pending_disable = -1; 6784 * 6785 * sched-in 6786 * perf_event_disable_inatomic() 6787 * @pending_disable = CPU-B; 6788 * irq_work_queue(); // FAILS 6789 * 6790 * irq_work_run() 6791 * perf_pending_irq() 6792 * 6793 * But the event runs on CPU-B and wants disabling there. 6794 */ 6795 irq_work_queue_on(&event->pending_irq, cpu); 6796 } 6797 6798 static void perf_pending_irq(struct irq_work *entry) 6799 { 6800 struct perf_event *event = container_of(entry, struct perf_event, pending_irq); 6801 int rctx; 6802 6803 /* 6804 * If we 'fail' here, that's OK, it means recursion is already disabled 6805 * and we won't recurse 'further'. 6806 */ 6807 rctx = perf_swevent_get_recursion_context(); 6808 6809 /* 6810 * The wakeup isn't bound to the context of the event -- it can happen 6811 * irrespective of where the event is. 6812 */ 6813 if (event->pending_wakeup) { 6814 event->pending_wakeup = 0; 6815 perf_event_wakeup(event); 6816 } 6817 6818 __perf_pending_irq(event); 6819 6820 if (rctx >= 0) 6821 perf_swevent_put_recursion_context(rctx); 6822 } 6823 6824 static void perf_pending_task(struct callback_head *head) 6825 { 6826 struct perf_event *event = container_of(head, struct perf_event, pending_task); 6827 int rctx; 6828 6829 /* 6830 * If we 'fail' here, that's OK, it means recursion is already disabled 6831 * and we won't recurse 'further'. 6832 */ 6833 preempt_disable_notrace(); 6834 rctx = perf_swevent_get_recursion_context(); 6835 6836 if (event->pending_work) { 6837 event->pending_work = 0; 6838 perf_sigtrap(event); 6839 local_dec(&event->ctx->nr_pending); 6840 } 6841 6842 if (rctx >= 0) 6843 perf_swevent_put_recursion_context(rctx); 6844 preempt_enable_notrace(); 6845 6846 put_event(event); 6847 } 6848 6849 #ifdef CONFIG_GUEST_PERF_EVENTS 6850 struct perf_guest_info_callbacks __rcu *perf_guest_cbs; 6851 6852 DEFINE_STATIC_CALL_RET0(__perf_guest_state, *perf_guest_cbs->state); 6853 DEFINE_STATIC_CALL_RET0(__perf_guest_get_ip, *perf_guest_cbs->get_ip); 6854 DEFINE_STATIC_CALL_RET0(__perf_guest_handle_intel_pt_intr, *perf_guest_cbs->handle_intel_pt_intr); 6855 6856 void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) 6857 { 6858 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs))) 6859 return; 6860 6861 rcu_assign_pointer(perf_guest_cbs, cbs); 6862 static_call_update(__perf_guest_state, cbs->state); 6863 static_call_update(__perf_guest_get_ip, cbs->get_ip); 6864 6865 /* Implementing ->handle_intel_pt_intr is optional. */ 6866 if (cbs->handle_intel_pt_intr) 6867 static_call_update(__perf_guest_handle_intel_pt_intr, 6868 cbs->handle_intel_pt_intr); 6869 } 6870 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks); 6871 6872 void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) 6873 { 6874 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs) != cbs)) 6875 return; 6876 6877 rcu_assign_pointer(perf_guest_cbs, NULL); 6878 static_call_update(__perf_guest_state, (void *)&__static_call_return0); 6879 static_call_update(__perf_guest_get_ip, (void *)&__static_call_return0); 6880 static_call_update(__perf_guest_handle_intel_pt_intr, 6881 (void *)&__static_call_return0); 6882 synchronize_rcu(); 6883 } 6884 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks); 6885 #endif 6886 6887 static void 6888 perf_output_sample_regs(struct perf_output_handle *handle, 6889 struct pt_regs *regs, u64 mask) 6890 { 6891 int bit; 6892 DECLARE_BITMAP(_mask, 64); 6893 6894 bitmap_from_u64(_mask, mask); 6895 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) { 6896 u64 val; 6897 6898 val = perf_reg_value(regs, bit); 6899 perf_output_put(handle, val); 6900 } 6901 } 6902 6903 static void perf_sample_regs_user(struct perf_regs *regs_user, 6904 struct pt_regs *regs) 6905 { 6906 if (user_mode(regs)) { 6907 regs_user->abi = perf_reg_abi(current); 6908 regs_user->regs = regs; 6909 } else if (!(current->flags & PF_KTHREAD)) { 6910 perf_get_regs_user(regs_user, regs); 6911 } else { 6912 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE; 6913 regs_user->regs = NULL; 6914 } 6915 } 6916 6917 static void perf_sample_regs_intr(struct perf_regs *regs_intr, 6918 struct pt_regs *regs) 6919 { 6920 regs_intr->regs = regs; 6921 regs_intr->abi = perf_reg_abi(current); 6922 } 6923 6924 6925 /* 6926 * Get remaining task size from user stack pointer. 6927 * 6928 * It'd be better to take stack vma map and limit this more 6929 * precisely, but there's no way to get it safely under interrupt, 6930 * so using TASK_SIZE as limit. 6931 */ 6932 static u64 perf_ustack_task_size(struct pt_regs *regs) 6933 { 6934 unsigned long addr = perf_user_stack_pointer(regs); 6935 6936 if (!addr || addr >= TASK_SIZE) 6937 return 0; 6938 6939 return TASK_SIZE - addr; 6940 } 6941 6942 static u16 6943 perf_sample_ustack_size(u16 stack_size, u16 header_size, 6944 struct pt_regs *regs) 6945 { 6946 u64 task_size; 6947 6948 /* No regs, no stack pointer, no dump. */ 6949 if (!regs) 6950 return 0; 6951 6952 /* 6953 * Check if we fit in with the requested stack size into the: 6954 * - TASK_SIZE 6955 * If we don't, we limit the size to the TASK_SIZE. 6956 * 6957 * - remaining sample size 6958 * If we don't, we customize the stack size to 6959 * fit in to the remaining sample size. 6960 */ 6961 6962 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs)); 6963 stack_size = min(stack_size, (u16) task_size); 6964 6965 /* Current header size plus static size and dynamic size. */ 6966 header_size += 2 * sizeof(u64); 6967 6968 /* Do we fit in with the current stack dump size? */ 6969 if ((u16) (header_size + stack_size) < header_size) { 6970 /* 6971 * If we overflow the maximum size for the sample, 6972 * we customize the stack dump size to fit in. 6973 */ 6974 stack_size = USHRT_MAX - header_size - sizeof(u64); 6975 stack_size = round_up(stack_size, sizeof(u64)); 6976 } 6977 6978 return stack_size; 6979 } 6980 6981 static void 6982 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size, 6983 struct pt_regs *regs) 6984 { 6985 /* Case of a kernel thread, nothing to dump */ 6986 if (!regs) { 6987 u64 size = 0; 6988 perf_output_put(handle, size); 6989 } else { 6990 unsigned long sp; 6991 unsigned int rem; 6992 u64 dyn_size; 6993 6994 /* 6995 * We dump: 6996 * static size 6997 * - the size requested by user or the best one we can fit 6998 * in to the sample max size 6999 * data 7000 * - user stack dump data 7001 * dynamic size 7002 * - the actual dumped size 7003 */ 7004 7005 /* Static size. */ 7006 perf_output_put(handle, dump_size); 7007 7008 /* Data. */ 7009 sp = perf_user_stack_pointer(regs); 7010 rem = __output_copy_user(handle, (void *) sp, dump_size); 7011 dyn_size = dump_size - rem; 7012 7013 perf_output_skip(handle, rem); 7014 7015 /* Dynamic size. */ 7016 perf_output_put(handle, dyn_size); 7017 } 7018 } 7019 7020 static unsigned long perf_prepare_sample_aux(struct perf_event *event, 7021 struct perf_sample_data *data, 7022 size_t size) 7023 { 7024 struct perf_event *sampler = event->aux_event; 7025 struct perf_buffer *rb; 7026 7027 data->aux_size = 0; 7028 7029 if (!sampler) 7030 goto out; 7031 7032 if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE)) 7033 goto out; 7034 7035 if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id())) 7036 goto out; 7037 7038 rb = ring_buffer_get(sampler); 7039 if (!rb) 7040 goto out; 7041 7042 /* 7043 * If this is an NMI hit inside sampling code, don't take 7044 * the sample. See also perf_aux_sample_output(). 7045 */ 7046 if (READ_ONCE(rb->aux_in_sampling)) { 7047 data->aux_size = 0; 7048 } else { 7049 size = min_t(size_t, size, perf_aux_size(rb)); 7050 data->aux_size = ALIGN(size, sizeof(u64)); 7051 } 7052 ring_buffer_put(rb); 7053 7054 out: 7055 return data->aux_size; 7056 } 7057 7058 static long perf_pmu_snapshot_aux(struct perf_buffer *rb, 7059 struct perf_event *event, 7060 struct perf_output_handle *handle, 7061 unsigned long size) 7062 { 7063 unsigned long flags; 7064 long ret; 7065 7066 /* 7067 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler 7068 * paths. If we start calling them in NMI context, they may race with 7069 * the IRQ ones, that is, for example, re-starting an event that's just 7070 * been stopped, which is why we're using a separate callback that 7071 * doesn't change the event state. 7072 * 7073 * IRQs need to be disabled to prevent IPIs from racing with us. 7074 */ 7075 local_irq_save(flags); 7076 /* 7077 * Guard against NMI hits inside the critical section; 7078 * see also perf_prepare_sample_aux(). 7079 */ 7080 WRITE_ONCE(rb->aux_in_sampling, 1); 7081 barrier(); 7082 7083 ret = event->pmu->snapshot_aux(event, handle, size); 7084 7085 barrier(); 7086 WRITE_ONCE(rb->aux_in_sampling, 0); 7087 local_irq_restore(flags); 7088 7089 return ret; 7090 } 7091 7092 static void perf_aux_sample_output(struct perf_event *event, 7093 struct perf_output_handle *handle, 7094 struct perf_sample_data *data) 7095 { 7096 struct perf_event *sampler = event->aux_event; 7097 struct perf_buffer *rb; 7098 unsigned long pad; 7099 long size; 7100 7101 if (WARN_ON_ONCE(!sampler || !data->aux_size)) 7102 return; 7103 7104 rb = ring_buffer_get(sampler); 7105 if (!rb) 7106 return; 7107 7108 size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size); 7109 7110 /* 7111 * An error here means that perf_output_copy() failed (returned a 7112 * non-zero surplus that it didn't copy), which in its current 7113 * enlightened implementation is not possible. If that changes, we'd 7114 * like to know. 7115 */ 7116 if (WARN_ON_ONCE(size < 0)) 7117 goto out_put; 7118 7119 /* 7120 * The pad comes from ALIGN()ing data->aux_size up to u64 in 7121 * perf_prepare_sample_aux(), so should not be more than that. 7122 */ 7123 pad = data->aux_size - size; 7124 if (WARN_ON_ONCE(pad >= sizeof(u64))) 7125 pad = 8; 7126 7127 if (pad) { 7128 u64 zero = 0; 7129 perf_output_copy(handle, &zero, pad); 7130 } 7131 7132 out_put: 7133 ring_buffer_put(rb); 7134 } 7135 7136 /* 7137 * A set of common sample data types saved even for non-sample records 7138 * when event->attr.sample_id_all is set. 7139 */ 7140 #define PERF_SAMPLE_ID_ALL (PERF_SAMPLE_TID | PERF_SAMPLE_TIME | \ 7141 PERF_SAMPLE_ID | PERF_SAMPLE_STREAM_ID | \ 7142 PERF_SAMPLE_CPU | PERF_SAMPLE_IDENTIFIER) 7143 7144 static void __perf_event_header__init_id(struct perf_sample_data *data, 7145 struct perf_event *event, 7146 u64 sample_type) 7147 { 7148 data->type = event->attr.sample_type; 7149 data->sample_flags |= data->type & PERF_SAMPLE_ID_ALL; 7150 7151 if (sample_type & PERF_SAMPLE_TID) { 7152 /* namespace issues */ 7153 data->tid_entry.pid = perf_event_pid(event, current); 7154 data->tid_entry.tid = perf_event_tid(event, current); 7155 } 7156 7157 if (sample_type & PERF_SAMPLE_TIME) 7158 data->time = perf_event_clock(event); 7159 7160 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER)) 7161 data->id = primary_event_id(event); 7162 7163 if (sample_type & PERF_SAMPLE_STREAM_ID) 7164 data->stream_id = event->id; 7165 7166 if (sample_type & PERF_SAMPLE_CPU) { 7167 data->cpu_entry.cpu = raw_smp_processor_id(); 7168 data->cpu_entry.reserved = 0; 7169 } 7170 } 7171 7172 void perf_event_header__init_id(struct perf_event_header *header, 7173 struct perf_sample_data *data, 7174 struct perf_event *event) 7175 { 7176 if (event->attr.sample_id_all) { 7177 header->size += event->id_header_size; 7178 __perf_event_header__init_id(data, event, event->attr.sample_type); 7179 } 7180 } 7181 7182 static void __perf_event__output_id_sample(struct perf_output_handle *handle, 7183 struct perf_sample_data *data) 7184 { 7185 u64 sample_type = data->type; 7186 7187 if (sample_type & PERF_SAMPLE_TID) 7188 perf_output_put(handle, data->tid_entry); 7189 7190 if (sample_type & PERF_SAMPLE_TIME) 7191 perf_output_put(handle, data->time); 7192 7193 if (sample_type & PERF_SAMPLE_ID) 7194 perf_output_put(handle, data->id); 7195 7196 if (sample_type & PERF_SAMPLE_STREAM_ID) 7197 perf_output_put(handle, data->stream_id); 7198 7199 if (sample_type & PERF_SAMPLE_CPU) 7200 perf_output_put(handle, data->cpu_entry); 7201 7202 if (sample_type & PERF_SAMPLE_IDENTIFIER) 7203 perf_output_put(handle, data->id); 7204 } 7205 7206 void perf_event__output_id_sample(struct perf_event *event, 7207 struct perf_output_handle *handle, 7208 struct perf_sample_data *sample) 7209 { 7210 if (event->attr.sample_id_all) 7211 __perf_event__output_id_sample(handle, sample); 7212 } 7213 7214 static void perf_output_read_one(struct perf_output_handle *handle, 7215 struct perf_event *event, 7216 u64 enabled, u64 running) 7217 { 7218 u64 read_format = event->attr.read_format; 7219 u64 values[5]; 7220 int n = 0; 7221 7222 values[n++] = perf_event_count(event); 7223 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { 7224 values[n++] = enabled + 7225 atomic64_read(&event->child_total_time_enabled); 7226 } 7227 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { 7228 values[n++] = running + 7229 atomic64_read(&event->child_total_time_running); 7230 } 7231 if (read_format & PERF_FORMAT_ID) 7232 values[n++] = primary_event_id(event); 7233 if (read_format & PERF_FORMAT_LOST) 7234 values[n++] = atomic64_read(&event->lost_samples); 7235 7236 __output_copy(handle, values, n * sizeof(u64)); 7237 } 7238 7239 static void perf_output_read_group(struct perf_output_handle *handle, 7240 struct perf_event *event, 7241 u64 enabled, u64 running) 7242 { 7243 struct perf_event *leader = event->group_leader, *sub; 7244 u64 read_format = event->attr.read_format; 7245 unsigned long flags; 7246 u64 values[6]; 7247 int n = 0; 7248 7249 /* 7250 * Disabling interrupts avoids all counter scheduling 7251 * (context switches, timer based rotation and IPIs). 7252 */ 7253 local_irq_save(flags); 7254 7255 values[n++] = 1 + leader->nr_siblings; 7256 7257 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 7258 values[n++] = enabled; 7259 7260 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 7261 values[n++] = running; 7262 7263 if ((leader != event) && 7264 (leader->state == PERF_EVENT_STATE_ACTIVE)) 7265 leader->pmu->read(leader); 7266 7267 values[n++] = perf_event_count(leader); 7268 if (read_format & PERF_FORMAT_ID) 7269 values[n++] = primary_event_id(leader); 7270 if (read_format & PERF_FORMAT_LOST) 7271 values[n++] = atomic64_read(&leader->lost_samples); 7272 7273 __output_copy(handle, values, n * sizeof(u64)); 7274 7275 for_each_sibling_event(sub, leader) { 7276 n = 0; 7277 7278 if ((sub != event) && 7279 (sub->state == PERF_EVENT_STATE_ACTIVE)) 7280 sub->pmu->read(sub); 7281 7282 values[n++] = perf_event_count(sub); 7283 if (read_format & PERF_FORMAT_ID) 7284 values[n++] = primary_event_id(sub); 7285 if (read_format & PERF_FORMAT_LOST) 7286 values[n++] = atomic64_read(&sub->lost_samples); 7287 7288 __output_copy(handle, values, n * sizeof(u64)); 7289 } 7290 7291 local_irq_restore(flags); 7292 } 7293 7294 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\ 7295 PERF_FORMAT_TOTAL_TIME_RUNNING) 7296 7297 /* 7298 * XXX PERF_SAMPLE_READ vs inherited events seems difficult. 7299 * 7300 * The problem is that its both hard and excessively expensive to iterate the 7301 * child list, not to mention that its impossible to IPI the children running 7302 * on another CPU, from interrupt/NMI context. 7303 */ 7304 static void perf_output_read(struct perf_output_handle *handle, 7305 struct perf_event *event) 7306 { 7307 u64 enabled = 0, running = 0, now; 7308 u64 read_format = event->attr.read_format; 7309 7310 /* 7311 * compute total_time_enabled, total_time_running 7312 * based on snapshot values taken when the event 7313 * was last scheduled in. 7314 * 7315 * we cannot simply called update_context_time() 7316 * because of locking issue as we are called in 7317 * NMI context 7318 */ 7319 if (read_format & PERF_FORMAT_TOTAL_TIMES) 7320 calc_timer_values(event, &now, &enabled, &running); 7321 7322 if (event->attr.read_format & PERF_FORMAT_GROUP) 7323 perf_output_read_group(handle, event, enabled, running); 7324 else 7325 perf_output_read_one(handle, event, enabled, running); 7326 } 7327 7328 void perf_output_sample(struct perf_output_handle *handle, 7329 struct perf_event_header *header, 7330 struct perf_sample_data *data, 7331 struct perf_event *event) 7332 { 7333 u64 sample_type = data->type; 7334 7335 perf_output_put(handle, *header); 7336 7337 if (sample_type & PERF_SAMPLE_IDENTIFIER) 7338 perf_output_put(handle, data->id); 7339 7340 if (sample_type & PERF_SAMPLE_IP) 7341 perf_output_put(handle, data->ip); 7342 7343 if (sample_type & PERF_SAMPLE_TID) 7344 perf_output_put(handle, data->tid_entry); 7345 7346 if (sample_type & PERF_SAMPLE_TIME) 7347 perf_output_put(handle, data->time); 7348 7349 if (sample_type & PERF_SAMPLE_ADDR) 7350 perf_output_put(handle, data->addr); 7351 7352 if (sample_type & PERF_SAMPLE_ID) 7353 perf_output_put(handle, data->id); 7354 7355 if (sample_type & PERF_SAMPLE_STREAM_ID) 7356 perf_output_put(handle, data->stream_id); 7357 7358 if (sample_type & PERF_SAMPLE_CPU) 7359 perf_output_put(handle, data->cpu_entry); 7360 7361 if (sample_type & PERF_SAMPLE_PERIOD) 7362 perf_output_put(handle, data->period); 7363 7364 if (sample_type & PERF_SAMPLE_READ) 7365 perf_output_read(handle, event); 7366 7367 if (sample_type & PERF_SAMPLE_CALLCHAIN) { 7368 int size = 1; 7369 7370 size += data->callchain->nr; 7371 size *= sizeof(u64); 7372 __output_copy(handle, data->callchain, size); 7373 } 7374 7375 if (sample_type & PERF_SAMPLE_RAW) { 7376 struct perf_raw_record *raw = data->raw; 7377 7378 if (raw) { 7379 struct perf_raw_frag *frag = &raw->frag; 7380 7381 perf_output_put(handle, raw->size); 7382 do { 7383 if (frag->copy) { 7384 __output_custom(handle, frag->copy, 7385 frag->data, frag->size); 7386 } else { 7387 __output_copy(handle, frag->data, 7388 frag->size); 7389 } 7390 if (perf_raw_frag_last(frag)) 7391 break; 7392 frag = frag->next; 7393 } while (1); 7394 if (frag->pad) 7395 __output_skip(handle, NULL, frag->pad); 7396 } else { 7397 struct { 7398 u32 size; 7399 u32 data; 7400 } raw = { 7401 .size = sizeof(u32), 7402 .data = 0, 7403 }; 7404 perf_output_put(handle, raw); 7405 } 7406 } 7407 7408 if (sample_type & PERF_SAMPLE_BRANCH_STACK) { 7409 if (data->br_stack) { 7410 size_t size; 7411 7412 size = data->br_stack->nr 7413 * sizeof(struct perf_branch_entry); 7414 7415 perf_output_put(handle, data->br_stack->nr); 7416 if (branch_sample_hw_index(event)) 7417 perf_output_put(handle, data->br_stack->hw_idx); 7418 perf_output_copy(handle, data->br_stack->entries, size); 7419 /* 7420 * Add the extension space which is appended 7421 * right after the struct perf_branch_stack. 7422 */ 7423 if (data->br_stack_cntr) { 7424 size = data->br_stack->nr * sizeof(u64); 7425 perf_output_copy(handle, data->br_stack_cntr, size); 7426 } 7427 } else { 7428 /* 7429 * we always store at least the value of nr 7430 */ 7431 u64 nr = 0; 7432 perf_output_put(handle, nr); 7433 } 7434 } 7435 7436 if (sample_type & PERF_SAMPLE_REGS_USER) { 7437 u64 abi = data->regs_user.abi; 7438 7439 /* 7440 * If there are no regs to dump, notice it through 7441 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). 7442 */ 7443 perf_output_put(handle, abi); 7444 7445 if (abi) { 7446 u64 mask = event->attr.sample_regs_user; 7447 perf_output_sample_regs(handle, 7448 data->regs_user.regs, 7449 mask); 7450 } 7451 } 7452 7453 if (sample_type & PERF_SAMPLE_STACK_USER) { 7454 perf_output_sample_ustack(handle, 7455 data->stack_user_size, 7456 data->regs_user.regs); 7457 } 7458 7459 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE) 7460 perf_output_put(handle, data->weight.full); 7461 7462 if (sample_type & PERF_SAMPLE_DATA_SRC) 7463 perf_output_put(handle, data->data_src.val); 7464 7465 if (sample_type & PERF_SAMPLE_TRANSACTION) 7466 perf_output_put(handle, data->txn); 7467 7468 if (sample_type & PERF_SAMPLE_REGS_INTR) { 7469 u64 abi = data->regs_intr.abi; 7470 /* 7471 * If there are no regs to dump, notice it through 7472 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). 7473 */ 7474 perf_output_put(handle, abi); 7475 7476 if (abi) { 7477 u64 mask = event->attr.sample_regs_intr; 7478 7479 perf_output_sample_regs(handle, 7480 data->regs_intr.regs, 7481 mask); 7482 } 7483 } 7484 7485 if (sample_type & PERF_SAMPLE_PHYS_ADDR) 7486 perf_output_put(handle, data->phys_addr); 7487 7488 if (sample_type & PERF_SAMPLE_CGROUP) 7489 perf_output_put(handle, data->cgroup); 7490 7491 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE) 7492 perf_output_put(handle, data->data_page_size); 7493 7494 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE) 7495 perf_output_put(handle, data->code_page_size); 7496 7497 if (sample_type & PERF_SAMPLE_AUX) { 7498 perf_output_put(handle, data->aux_size); 7499 7500 if (data->aux_size) 7501 perf_aux_sample_output(event, handle, data); 7502 } 7503 7504 if (!event->attr.watermark) { 7505 int wakeup_events = event->attr.wakeup_events; 7506 7507 if (wakeup_events) { 7508 struct perf_buffer *rb = handle->rb; 7509 int events = local_inc_return(&rb->events); 7510 7511 if (events >= wakeup_events) { 7512 local_sub(wakeup_events, &rb->events); 7513 local_inc(&rb->wakeup); 7514 } 7515 } 7516 } 7517 } 7518 7519 static u64 perf_virt_to_phys(u64 virt) 7520 { 7521 u64 phys_addr = 0; 7522 7523 if (!virt) 7524 return 0; 7525 7526 if (virt >= TASK_SIZE) { 7527 /* If it's vmalloc()d memory, leave phys_addr as 0 */ 7528 if (virt_addr_valid((void *)(uintptr_t)virt) && 7529 !(virt >= VMALLOC_START && virt < VMALLOC_END)) 7530 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt); 7531 } else { 7532 /* 7533 * Walking the pages tables for user address. 7534 * Interrupts are disabled, so it prevents any tear down 7535 * of the page tables. 7536 * Try IRQ-safe get_user_page_fast_only first. 7537 * If failed, leave phys_addr as 0. 7538 */ 7539 if (current->mm != NULL) { 7540 struct page *p; 7541 7542 pagefault_disable(); 7543 if (get_user_page_fast_only(virt, 0, &p)) { 7544 phys_addr = page_to_phys(p) + virt % PAGE_SIZE; 7545 put_page(p); 7546 } 7547 pagefault_enable(); 7548 } 7549 } 7550 7551 return phys_addr; 7552 } 7553 7554 /* 7555 * Return the pagetable size of a given virtual address. 7556 */ 7557 static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr) 7558 { 7559 u64 size = 0; 7560 7561 #ifdef CONFIG_HAVE_FAST_GUP 7562 pgd_t *pgdp, pgd; 7563 p4d_t *p4dp, p4d; 7564 pud_t *pudp, pud; 7565 pmd_t *pmdp, pmd; 7566 pte_t *ptep, pte; 7567 7568 pgdp = pgd_offset(mm, addr); 7569 pgd = READ_ONCE(*pgdp); 7570 if (pgd_none(pgd)) 7571 return 0; 7572 7573 if (pgd_leaf(pgd)) 7574 return pgd_leaf_size(pgd); 7575 7576 p4dp = p4d_offset_lockless(pgdp, pgd, addr); 7577 p4d = READ_ONCE(*p4dp); 7578 if (!p4d_present(p4d)) 7579 return 0; 7580 7581 if (p4d_leaf(p4d)) 7582 return p4d_leaf_size(p4d); 7583 7584 pudp = pud_offset_lockless(p4dp, p4d, addr); 7585 pud = READ_ONCE(*pudp); 7586 if (!pud_present(pud)) 7587 return 0; 7588 7589 if (pud_leaf(pud)) 7590 return pud_leaf_size(pud); 7591 7592 pmdp = pmd_offset_lockless(pudp, pud, addr); 7593 again: 7594 pmd = pmdp_get_lockless(pmdp); 7595 if (!pmd_present(pmd)) 7596 return 0; 7597 7598 if (pmd_leaf(pmd)) 7599 return pmd_leaf_size(pmd); 7600 7601 ptep = pte_offset_map(&pmd, addr); 7602 if (!ptep) 7603 goto again; 7604 7605 pte = ptep_get_lockless(ptep); 7606 if (pte_present(pte)) 7607 size = pte_leaf_size(pte); 7608 pte_unmap(ptep); 7609 #endif /* CONFIG_HAVE_FAST_GUP */ 7610 7611 return size; 7612 } 7613 7614 static u64 perf_get_page_size(unsigned long addr) 7615 { 7616 struct mm_struct *mm; 7617 unsigned long flags; 7618 u64 size; 7619 7620 if (!addr) 7621 return 0; 7622 7623 /* 7624 * Software page-table walkers must disable IRQs, 7625 * which prevents any tear down of the page tables. 7626 */ 7627 local_irq_save(flags); 7628 7629 mm = current->mm; 7630 if (!mm) { 7631 /* 7632 * For kernel threads and the like, use init_mm so that 7633 * we can find kernel memory. 7634 */ 7635 mm = &init_mm; 7636 } 7637 7638 size = perf_get_pgtable_size(mm, addr); 7639 7640 local_irq_restore(flags); 7641 7642 return size; 7643 } 7644 7645 static struct perf_callchain_entry __empty_callchain = { .nr = 0, }; 7646 7647 struct perf_callchain_entry * 7648 perf_callchain(struct perf_event *event, struct pt_regs *regs) 7649 { 7650 bool kernel = !event->attr.exclude_callchain_kernel; 7651 bool user = !event->attr.exclude_callchain_user; 7652 /* Disallow cross-task user callchains. */ 7653 bool crosstask = event->ctx->task && event->ctx->task != current; 7654 const u32 max_stack = event->attr.sample_max_stack; 7655 struct perf_callchain_entry *callchain; 7656 7657 if (!kernel && !user) 7658 return &__empty_callchain; 7659 7660 callchain = get_perf_callchain(regs, 0, kernel, user, 7661 max_stack, crosstask, true); 7662 return callchain ?: &__empty_callchain; 7663 } 7664 7665 static __always_inline u64 __cond_set(u64 flags, u64 s, u64 d) 7666 { 7667 return d * !!(flags & s); 7668 } 7669 7670 void perf_prepare_sample(struct perf_sample_data *data, 7671 struct perf_event *event, 7672 struct pt_regs *regs) 7673 { 7674 u64 sample_type = event->attr.sample_type; 7675 u64 filtered_sample_type; 7676 7677 /* 7678 * Add the sample flags that are dependent to others. And clear the 7679 * sample flags that have already been done by the PMU driver. 7680 */ 7681 filtered_sample_type = sample_type; 7682 filtered_sample_type |= __cond_set(sample_type, PERF_SAMPLE_CODE_PAGE_SIZE, 7683 PERF_SAMPLE_IP); 7684 filtered_sample_type |= __cond_set(sample_type, PERF_SAMPLE_DATA_PAGE_SIZE | 7685 PERF_SAMPLE_PHYS_ADDR, PERF_SAMPLE_ADDR); 7686 filtered_sample_type |= __cond_set(sample_type, PERF_SAMPLE_STACK_USER, 7687 PERF_SAMPLE_REGS_USER); 7688 filtered_sample_type &= ~data->sample_flags; 7689 7690 if (filtered_sample_type == 0) { 7691 /* Make sure it has the correct data->type for output */ 7692 data->type = event->attr.sample_type; 7693 return; 7694 } 7695 7696 __perf_event_header__init_id(data, event, filtered_sample_type); 7697 7698 if (filtered_sample_type & PERF_SAMPLE_IP) { 7699 data->ip = perf_instruction_pointer(regs); 7700 data->sample_flags |= PERF_SAMPLE_IP; 7701 } 7702 7703 if (filtered_sample_type & PERF_SAMPLE_CALLCHAIN) 7704 perf_sample_save_callchain(data, event, regs); 7705 7706 if (filtered_sample_type & PERF_SAMPLE_RAW) { 7707 data->raw = NULL; 7708 data->dyn_size += sizeof(u64); 7709 data->sample_flags |= PERF_SAMPLE_RAW; 7710 } 7711 7712 if (filtered_sample_type & PERF_SAMPLE_BRANCH_STACK) { 7713 data->br_stack = NULL; 7714 data->dyn_size += sizeof(u64); 7715 data->sample_flags |= PERF_SAMPLE_BRANCH_STACK; 7716 } 7717 7718 if (filtered_sample_type & PERF_SAMPLE_REGS_USER) 7719 perf_sample_regs_user(&data->regs_user, regs); 7720 7721 /* 7722 * It cannot use the filtered_sample_type here as REGS_USER can be set 7723 * by STACK_USER (using __cond_set() above) and we don't want to update 7724 * the dyn_size if it's not requested by users. 7725 */ 7726 if ((sample_type & ~data->sample_flags) & PERF_SAMPLE_REGS_USER) { 7727 /* regs dump ABI info */ 7728 int size = sizeof(u64); 7729 7730 if (data->regs_user.regs) { 7731 u64 mask = event->attr.sample_regs_user; 7732 size += hweight64(mask) * sizeof(u64); 7733 } 7734 7735 data->dyn_size += size; 7736 data->sample_flags |= PERF_SAMPLE_REGS_USER; 7737 } 7738 7739 if (filtered_sample_type & PERF_SAMPLE_STACK_USER) { 7740 /* 7741 * Either we need PERF_SAMPLE_STACK_USER bit to be always 7742 * processed as the last one or have additional check added 7743 * in case new sample type is added, because we could eat 7744 * up the rest of the sample size. 7745 */ 7746 u16 stack_size = event->attr.sample_stack_user; 7747 u16 header_size = perf_sample_data_size(data, event); 7748 u16 size = sizeof(u64); 7749 7750 stack_size = perf_sample_ustack_size(stack_size, header_size, 7751 data->regs_user.regs); 7752 7753 /* 7754 * If there is something to dump, add space for the dump 7755 * itself and for the field that tells the dynamic size, 7756 * which is how many have been actually dumped. 7757 */ 7758 if (stack_size) 7759 size += sizeof(u64) + stack_size; 7760 7761 data->stack_user_size = stack_size; 7762 data->dyn_size += size; 7763 data->sample_flags |= PERF_SAMPLE_STACK_USER; 7764 } 7765 7766 if (filtered_sample_type & PERF_SAMPLE_WEIGHT_TYPE) { 7767 data->weight.full = 0; 7768 data->sample_flags |= PERF_SAMPLE_WEIGHT_TYPE; 7769 } 7770 7771 if (filtered_sample_type & PERF_SAMPLE_DATA_SRC) { 7772 data->data_src.val = PERF_MEM_NA; 7773 data->sample_flags |= PERF_SAMPLE_DATA_SRC; 7774 } 7775 7776 if (filtered_sample_type & PERF_SAMPLE_TRANSACTION) { 7777 data->txn = 0; 7778 data->sample_flags |= PERF_SAMPLE_TRANSACTION; 7779 } 7780 7781 if (filtered_sample_type & PERF_SAMPLE_ADDR) { 7782 data->addr = 0; 7783 data->sample_flags |= PERF_SAMPLE_ADDR; 7784 } 7785 7786 if (filtered_sample_type & PERF_SAMPLE_REGS_INTR) { 7787 /* regs dump ABI info */ 7788 int size = sizeof(u64); 7789 7790 perf_sample_regs_intr(&data->regs_intr, regs); 7791 7792 if (data->regs_intr.regs) { 7793 u64 mask = event->attr.sample_regs_intr; 7794 7795 size += hweight64(mask) * sizeof(u64); 7796 } 7797 7798 data->dyn_size += size; 7799 data->sample_flags |= PERF_SAMPLE_REGS_INTR; 7800 } 7801 7802 if (filtered_sample_type & PERF_SAMPLE_PHYS_ADDR) { 7803 data->phys_addr = perf_virt_to_phys(data->addr); 7804 data->sample_flags |= PERF_SAMPLE_PHYS_ADDR; 7805 } 7806 7807 #ifdef CONFIG_CGROUP_PERF 7808 if (filtered_sample_type & PERF_SAMPLE_CGROUP) { 7809 struct cgroup *cgrp; 7810 7811 /* protected by RCU */ 7812 cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup; 7813 data->cgroup = cgroup_id(cgrp); 7814 data->sample_flags |= PERF_SAMPLE_CGROUP; 7815 } 7816 #endif 7817 7818 /* 7819 * PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't 7820 * require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr, 7821 * but the value will not dump to the userspace. 7822 */ 7823 if (filtered_sample_type & PERF_SAMPLE_DATA_PAGE_SIZE) { 7824 data->data_page_size = perf_get_page_size(data->addr); 7825 data->sample_flags |= PERF_SAMPLE_DATA_PAGE_SIZE; 7826 } 7827 7828 if (filtered_sample_type & PERF_SAMPLE_CODE_PAGE_SIZE) { 7829 data->code_page_size = perf_get_page_size(data->ip); 7830 data->sample_flags |= PERF_SAMPLE_CODE_PAGE_SIZE; 7831 } 7832 7833 if (filtered_sample_type & PERF_SAMPLE_AUX) { 7834 u64 size; 7835 u16 header_size = perf_sample_data_size(data, event); 7836 7837 header_size += sizeof(u64); /* size */ 7838 7839 /* 7840 * Given the 16bit nature of header::size, an AUX sample can 7841 * easily overflow it, what with all the preceding sample bits. 7842 * Make sure this doesn't happen by using up to U16_MAX bytes 7843 * per sample in total (rounded down to 8 byte boundary). 7844 */ 7845 size = min_t(size_t, U16_MAX - header_size, 7846 event->attr.aux_sample_size); 7847 size = rounddown(size, 8); 7848 size = perf_prepare_sample_aux(event, data, size); 7849 7850 WARN_ON_ONCE(size + header_size > U16_MAX); 7851 data->dyn_size += size + sizeof(u64); /* size above */ 7852 data->sample_flags |= PERF_SAMPLE_AUX; 7853 } 7854 } 7855 7856 void perf_prepare_header(struct perf_event_header *header, 7857 struct perf_sample_data *data, 7858 struct perf_event *event, 7859 struct pt_regs *regs) 7860 { 7861 header->type = PERF_RECORD_SAMPLE; 7862 header->size = perf_sample_data_size(data, event); 7863 header->misc = perf_misc_flags(regs); 7864 7865 /* 7866 * If you're adding more sample types here, you likely need to do 7867 * something about the overflowing header::size, like repurpose the 7868 * lowest 3 bits of size, which should be always zero at the moment. 7869 * This raises a more important question, do we really need 512k sized 7870 * samples and why, so good argumentation is in order for whatever you 7871 * do here next. 7872 */ 7873 WARN_ON_ONCE(header->size & 7); 7874 } 7875 7876 static __always_inline int 7877 __perf_event_output(struct perf_event *event, 7878 struct perf_sample_data *data, 7879 struct pt_regs *regs, 7880 int (*output_begin)(struct perf_output_handle *, 7881 struct perf_sample_data *, 7882 struct perf_event *, 7883 unsigned int)) 7884 { 7885 struct perf_output_handle handle; 7886 struct perf_event_header header; 7887 int err; 7888 7889 /* protect the callchain buffers */ 7890 rcu_read_lock(); 7891 7892 perf_prepare_sample(data, event, regs); 7893 perf_prepare_header(&header, data, event, regs); 7894 7895 err = output_begin(&handle, data, event, header.size); 7896 if (err) 7897 goto exit; 7898 7899 perf_output_sample(&handle, &header, data, event); 7900 7901 perf_output_end(&handle); 7902 7903 exit: 7904 rcu_read_unlock(); 7905 return err; 7906 } 7907 7908 void 7909 perf_event_output_forward(struct perf_event *event, 7910 struct perf_sample_data *data, 7911 struct pt_regs *regs) 7912 { 7913 __perf_event_output(event, data, regs, perf_output_begin_forward); 7914 } 7915 7916 void 7917 perf_event_output_backward(struct perf_event *event, 7918 struct perf_sample_data *data, 7919 struct pt_regs *regs) 7920 { 7921 __perf_event_output(event, data, regs, perf_output_begin_backward); 7922 } 7923 7924 int 7925 perf_event_output(struct perf_event *event, 7926 struct perf_sample_data *data, 7927 struct pt_regs *regs) 7928 { 7929 return __perf_event_output(event, data, regs, perf_output_begin); 7930 } 7931 7932 /* 7933 * read event_id 7934 */ 7935 7936 struct perf_read_event { 7937 struct perf_event_header header; 7938 7939 u32 pid; 7940 u32 tid; 7941 }; 7942 7943 static void 7944 perf_event_read_event(struct perf_event *event, 7945 struct task_struct *task) 7946 { 7947 struct perf_output_handle handle; 7948 struct perf_sample_data sample; 7949 struct perf_read_event read_event = { 7950 .header = { 7951 .type = PERF_RECORD_READ, 7952 .misc = 0, 7953 .size = sizeof(read_event) + event->read_size, 7954 }, 7955 .pid = perf_event_pid(event, task), 7956 .tid = perf_event_tid(event, task), 7957 }; 7958 int ret; 7959 7960 perf_event_header__init_id(&read_event.header, &sample, event); 7961 ret = perf_output_begin(&handle, &sample, event, read_event.header.size); 7962 if (ret) 7963 return; 7964 7965 perf_output_put(&handle, read_event); 7966 perf_output_read(&handle, event); 7967 perf_event__output_id_sample(event, &handle, &sample); 7968 7969 perf_output_end(&handle); 7970 } 7971 7972 typedef void (perf_iterate_f)(struct perf_event *event, void *data); 7973 7974 static void 7975 perf_iterate_ctx(struct perf_event_context *ctx, 7976 perf_iterate_f output, 7977 void *data, bool all) 7978 { 7979 struct perf_event *event; 7980 7981 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 7982 if (!all) { 7983 if (event->state < PERF_EVENT_STATE_INACTIVE) 7984 continue; 7985 if (!event_filter_match(event)) 7986 continue; 7987 } 7988 7989 output(event, data); 7990 } 7991 } 7992 7993 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data) 7994 { 7995 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events); 7996 struct perf_event *event; 7997 7998 list_for_each_entry_rcu(event, &pel->list, sb_list) { 7999 /* 8000 * Skip events that are not fully formed yet; ensure that 8001 * if we observe event->ctx, both event and ctx will be 8002 * complete enough. See perf_install_in_context(). 8003 */ 8004 if (!smp_load_acquire(&event->ctx)) 8005 continue; 8006 8007 if (event->state < PERF_EVENT_STATE_INACTIVE) 8008 continue; 8009 if (!event_filter_match(event)) 8010 continue; 8011 output(event, data); 8012 } 8013 } 8014 8015 /* 8016 * Iterate all events that need to receive side-band events. 8017 * 8018 * For new callers; ensure that account_pmu_sb_event() includes 8019 * your event, otherwise it might not get delivered. 8020 */ 8021 static void 8022 perf_iterate_sb(perf_iterate_f output, void *data, 8023 struct perf_event_context *task_ctx) 8024 { 8025 struct perf_event_context *ctx; 8026 8027 rcu_read_lock(); 8028 preempt_disable(); 8029 8030 /* 8031 * If we have task_ctx != NULL we only notify the task context itself. 8032 * The task_ctx is set only for EXIT events before releasing task 8033 * context. 8034 */ 8035 if (task_ctx) { 8036 perf_iterate_ctx(task_ctx, output, data, false); 8037 goto done; 8038 } 8039 8040 perf_iterate_sb_cpu(output, data); 8041 8042 ctx = rcu_dereference(current->perf_event_ctxp); 8043 if (ctx) 8044 perf_iterate_ctx(ctx, output, data, false); 8045 done: 8046 preempt_enable(); 8047 rcu_read_unlock(); 8048 } 8049 8050 /* 8051 * Clear all file-based filters at exec, they'll have to be 8052 * re-instated when/if these objects are mmapped again. 8053 */ 8054 static void perf_event_addr_filters_exec(struct perf_event *event, void *data) 8055 { 8056 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 8057 struct perf_addr_filter *filter; 8058 unsigned int restart = 0, count = 0; 8059 unsigned long flags; 8060 8061 if (!has_addr_filter(event)) 8062 return; 8063 8064 raw_spin_lock_irqsave(&ifh->lock, flags); 8065 list_for_each_entry(filter, &ifh->list, entry) { 8066 if (filter->path.dentry) { 8067 event->addr_filter_ranges[count].start = 0; 8068 event->addr_filter_ranges[count].size = 0; 8069 restart++; 8070 } 8071 8072 count++; 8073 } 8074 8075 if (restart) 8076 event->addr_filters_gen++; 8077 raw_spin_unlock_irqrestore(&ifh->lock, flags); 8078 8079 if (restart) 8080 perf_event_stop(event, 1); 8081 } 8082 8083 void perf_event_exec(void) 8084 { 8085 struct perf_event_context *ctx; 8086 8087 ctx = perf_pin_task_context(current); 8088 if (!ctx) 8089 return; 8090 8091 perf_event_enable_on_exec(ctx); 8092 perf_event_remove_on_exec(ctx); 8093 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL, true); 8094 8095 perf_unpin_context(ctx); 8096 put_ctx(ctx); 8097 } 8098 8099 struct remote_output { 8100 struct perf_buffer *rb; 8101 int err; 8102 }; 8103 8104 static void __perf_event_output_stop(struct perf_event *event, void *data) 8105 { 8106 struct perf_event *parent = event->parent; 8107 struct remote_output *ro = data; 8108 struct perf_buffer *rb = ro->rb; 8109 struct stop_event_data sd = { 8110 .event = event, 8111 }; 8112 8113 if (!has_aux(event)) 8114 return; 8115 8116 if (!parent) 8117 parent = event; 8118 8119 /* 8120 * In case of inheritance, it will be the parent that links to the 8121 * ring-buffer, but it will be the child that's actually using it. 8122 * 8123 * We are using event::rb to determine if the event should be stopped, 8124 * however this may race with ring_buffer_attach() (through set_output), 8125 * which will make us skip the event that actually needs to be stopped. 8126 * So ring_buffer_attach() has to stop an aux event before re-assigning 8127 * its rb pointer. 8128 */ 8129 if (rcu_dereference(parent->rb) == rb) 8130 ro->err = __perf_event_stop(&sd); 8131 } 8132 8133 static int __perf_pmu_output_stop(void *info) 8134 { 8135 struct perf_event *event = info; 8136 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); 8137 struct remote_output ro = { 8138 .rb = event->rb, 8139 }; 8140 8141 rcu_read_lock(); 8142 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false); 8143 if (cpuctx->task_ctx) 8144 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop, 8145 &ro, false); 8146 rcu_read_unlock(); 8147 8148 return ro.err; 8149 } 8150 8151 static void perf_pmu_output_stop(struct perf_event *event) 8152 { 8153 struct perf_event *iter; 8154 int err, cpu; 8155 8156 restart: 8157 rcu_read_lock(); 8158 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) { 8159 /* 8160 * For per-CPU events, we need to make sure that neither they 8161 * nor their children are running; for cpu==-1 events it's 8162 * sufficient to stop the event itself if it's active, since 8163 * it can't have children. 8164 */ 8165 cpu = iter->cpu; 8166 if (cpu == -1) 8167 cpu = READ_ONCE(iter->oncpu); 8168 8169 if (cpu == -1) 8170 continue; 8171 8172 err = cpu_function_call(cpu, __perf_pmu_output_stop, event); 8173 if (err == -EAGAIN) { 8174 rcu_read_unlock(); 8175 goto restart; 8176 } 8177 } 8178 rcu_read_unlock(); 8179 } 8180 8181 /* 8182 * task tracking -- fork/exit 8183 * 8184 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task 8185 */ 8186 8187 struct perf_task_event { 8188 struct task_struct *task; 8189 struct perf_event_context *task_ctx; 8190 8191 struct { 8192 struct perf_event_header header; 8193 8194 u32 pid; 8195 u32 ppid; 8196 u32 tid; 8197 u32 ptid; 8198 u64 time; 8199 } event_id; 8200 }; 8201 8202 static int perf_event_task_match(struct perf_event *event) 8203 { 8204 return event->attr.comm || event->attr.mmap || 8205 event->attr.mmap2 || event->attr.mmap_data || 8206 event->attr.task; 8207 } 8208 8209 static void perf_event_task_output(struct perf_event *event, 8210 void *data) 8211 { 8212 struct perf_task_event *task_event = data; 8213 struct perf_output_handle handle; 8214 struct perf_sample_data sample; 8215 struct task_struct *task = task_event->task; 8216 int ret, size = task_event->event_id.header.size; 8217 8218 if (!perf_event_task_match(event)) 8219 return; 8220 8221 perf_event_header__init_id(&task_event->event_id.header, &sample, event); 8222 8223 ret = perf_output_begin(&handle, &sample, event, 8224 task_event->event_id.header.size); 8225 if (ret) 8226 goto out; 8227 8228 task_event->event_id.pid = perf_event_pid(event, task); 8229 task_event->event_id.tid = perf_event_tid(event, task); 8230 8231 if (task_event->event_id.header.type == PERF_RECORD_EXIT) { 8232 task_event->event_id.ppid = perf_event_pid(event, 8233 task->real_parent); 8234 task_event->event_id.ptid = perf_event_pid(event, 8235 task->real_parent); 8236 } else { /* PERF_RECORD_FORK */ 8237 task_event->event_id.ppid = perf_event_pid(event, current); 8238 task_event->event_id.ptid = perf_event_tid(event, current); 8239 } 8240 8241 task_event->event_id.time = perf_event_clock(event); 8242 8243 perf_output_put(&handle, task_event->event_id); 8244 8245 perf_event__output_id_sample(event, &handle, &sample); 8246 8247 perf_output_end(&handle); 8248 out: 8249 task_event->event_id.header.size = size; 8250 } 8251 8252 static void perf_event_task(struct task_struct *task, 8253 struct perf_event_context *task_ctx, 8254 int new) 8255 { 8256 struct perf_task_event task_event; 8257 8258 if (!atomic_read(&nr_comm_events) && 8259 !atomic_read(&nr_mmap_events) && 8260 !atomic_read(&nr_task_events)) 8261 return; 8262 8263 task_event = (struct perf_task_event){ 8264 .task = task, 8265 .task_ctx = task_ctx, 8266 .event_id = { 8267 .header = { 8268 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT, 8269 .misc = 0, 8270 .size = sizeof(task_event.event_id), 8271 }, 8272 /* .pid */ 8273 /* .ppid */ 8274 /* .tid */ 8275 /* .ptid */ 8276 /* .time */ 8277 }, 8278 }; 8279 8280 perf_iterate_sb(perf_event_task_output, 8281 &task_event, 8282 task_ctx); 8283 } 8284 8285 void perf_event_fork(struct task_struct *task) 8286 { 8287 perf_event_task(task, NULL, 1); 8288 perf_event_namespaces(task); 8289 } 8290 8291 /* 8292 * comm tracking 8293 */ 8294 8295 struct perf_comm_event { 8296 struct task_struct *task; 8297 char *comm; 8298 int comm_size; 8299 8300 struct { 8301 struct perf_event_header header; 8302 8303 u32 pid; 8304 u32 tid; 8305 } event_id; 8306 }; 8307 8308 static int perf_event_comm_match(struct perf_event *event) 8309 { 8310 return event->attr.comm; 8311 } 8312 8313 static void perf_event_comm_output(struct perf_event *event, 8314 void *data) 8315 { 8316 struct perf_comm_event *comm_event = data; 8317 struct perf_output_handle handle; 8318 struct perf_sample_data sample; 8319 int size = comm_event->event_id.header.size; 8320 int ret; 8321 8322 if (!perf_event_comm_match(event)) 8323 return; 8324 8325 perf_event_header__init_id(&comm_event->event_id.header, &sample, event); 8326 ret = perf_output_begin(&handle, &sample, event, 8327 comm_event->event_id.header.size); 8328 8329 if (ret) 8330 goto out; 8331 8332 comm_event->event_id.pid = perf_event_pid(event, comm_event->task); 8333 comm_event->event_id.tid = perf_event_tid(event, comm_event->task); 8334 8335 perf_output_put(&handle, comm_event->event_id); 8336 __output_copy(&handle, comm_event->comm, 8337 comm_event->comm_size); 8338 8339 perf_event__output_id_sample(event, &handle, &sample); 8340 8341 perf_output_end(&handle); 8342 out: 8343 comm_event->event_id.header.size = size; 8344 } 8345 8346 static void perf_event_comm_event(struct perf_comm_event *comm_event) 8347 { 8348 char comm[TASK_COMM_LEN]; 8349 unsigned int size; 8350 8351 memset(comm, 0, sizeof(comm)); 8352 strscpy(comm, comm_event->task->comm, sizeof(comm)); 8353 size = ALIGN(strlen(comm)+1, sizeof(u64)); 8354 8355 comm_event->comm = comm; 8356 comm_event->comm_size = size; 8357 8358 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size; 8359 8360 perf_iterate_sb(perf_event_comm_output, 8361 comm_event, 8362 NULL); 8363 } 8364 8365 void perf_event_comm(struct task_struct *task, bool exec) 8366 { 8367 struct perf_comm_event comm_event; 8368 8369 if (!atomic_read(&nr_comm_events)) 8370 return; 8371 8372 comm_event = (struct perf_comm_event){ 8373 .task = task, 8374 /* .comm */ 8375 /* .comm_size */ 8376 .event_id = { 8377 .header = { 8378 .type = PERF_RECORD_COMM, 8379 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0, 8380 /* .size */ 8381 }, 8382 /* .pid */ 8383 /* .tid */ 8384 }, 8385 }; 8386 8387 perf_event_comm_event(&comm_event); 8388 } 8389 8390 /* 8391 * namespaces tracking 8392 */ 8393 8394 struct perf_namespaces_event { 8395 struct task_struct *task; 8396 8397 struct { 8398 struct perf_event_header header; 8399 8400 u32 pid; 8401 u32 tid; 8402 u64 nr_namespaces; 8403 struct perf_ns_link_info link_info[NR_NAMESPACES]; 8404 } event_id; 8405 }; 8406 8407 static int perf_event_namespaces_match(struct perf_event *event) 8408 { 8409 return event->attr.namespaces; 8410 } 8411 8412 static void perf_event_namespaces_output(struct perf_event *event, 8413 void *data) 8414 { 8415 struct perf_namespaces_event *namespaces_event = data; 8416 struct perf_output_handle handle; 8417 struct perf_sample_data sample; 8418 u16 header_size = namespaces_event->event_id.header.size; 8419 int ret; 8420 8421 if (!perf_event_namespaces_match(event)) 8422 return; 8423 8424 perf_event_header__init_id(&namespaces_event->event_id.header, 8425 &sample, event); 8426 ret = perf_output_begin(&handle, &sample, event, 8427 namespaces_event->event_id.header.size); 8428 if (ret) 8429 goto out; 8430 8431 namespaces_event->event_id.pid = perf_event_pid(event, 8432 namespaces_event->task); 8433 namespaces_event->event_id.tid = perf_event_tid(event, 8434 namespaces_event->task); 8435 8436 perf_output_put(&handle, namespaces_event->event_id); 8437 8438 perf_event__output_id_sample(event, &handle, &sample); 8439 8440 perf_output_end(&handle); 8441 out: 8442 namespaces_event->event_id.header.size = header_size; 8443 } 8444 8445 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info, 8446 struct task_struct *task, 8447 const struct proc_ns_operations *ns_ops) 8448 { 8449 struct path ns_path; 8450 struct inode *ns_inode; 8451 int error; 8452 8453 error = ns_get_path(&ns_path, task, ns_ops); 8454 if (!error) { 8455 ns_inode = ns_path.dentry->d_inode; 8456 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev); 8457 ns_link_info->ino = ns_inode->i_ino; 8458 path_put(&ns_path); 8459 } 8460 } 8461 8462 void perf_event_namespaces(struct task_struct *task) 8463 { 8464 struct perf_namespaces_event namespaces_event; 8465 struct perf_ns_link_info *ns_link_info; 8466 8467 if (!atomic_read(&nr_namespaces_events)) 8468 return; 8469 8470 namespaces_event = (struct perf_namespaces_event){ 8471 .task = task, 8472 .event_id = { 8473 .header = { 8474 .type = PERF_RECORD_NAMESPACES, 8475 .misc = 0, 8476 .size = sizeof(namespaces_event.event_id), 8477 }, 8478 /* .pid */ 8479 /* .tid */ 8480 .nr_namespaces = NR_NAMESPACES, 8481 /* .link_info[NR_NAMESPACES] */ 8482 }, 8483 }; 8484 8485 ns_link_info = namespaces_event.event_id.link_info; 8486 8487 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX], 8488 task, &mntns_operations); 8489 8490 #ifdef CONFIG_USER_NS 8491 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX], 8492 task, &userns_operations); 8493 #endif 8494 #ifdef CONFIG_NET_NS 8495 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX], 8496 task, &netns_operations); 8497 #endif 8498 #ifdef CONFIG_UTS_NS 8499 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX], 8500 task, &utsns_operations); 8501 #endif 8502 #ifdef CONFIG_IPC_NS 8503 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX], 8504 task, &ipcns_operations); 8505 #endif 8506 #ifdef CONFIG_PID_NS 8507 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX], 8508 task, &pidns_operations); 8509 #endif 8510 #ifdef CONFIG_CGROUPS 8511 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX], 8512 task, &cgroupns_operations); 8513 #endif 8514 8515 perf_iterate_sb(perf_event_namespaces_output, 8516 &namespaces_event, 8517 NULL); 8518 } 8519 8520 /* 8521 * cgroup tracking 8522 */ 8523 #ifdef CONFIG_CGROUP_PERF 8524 8525 struct perf_cgroup_event { 8526 char *path; 8527 int path_size; 8528 struct { 8529 struct perf_event_header header; 8530 u64 id; 8531 char path[]; 8532 } event_id; 8533 }; 8534 8535 static int perf_event_cgroup_match(struct perf_event *event) 8536 { 8537 return event->attr.cgroup; 8538 } 8539 8540 static void perf_event_cgroup_output(struct perf_event *event, void *data) 8541 { 8542 struct perf_cgroup_event *cgroup_event = data; 8543 struct perf_output_handle handle; 8544 struct perf_sample_data sample; 8545 u16 header_size = cgroup_event->event_id.header.size; 8546 int ret; 8547 8548 if (!perf_event_cgroup_match(event)) 8549 return; 8550 8551 perf_event_header__init_id(&cgroup_event->event_id.header, 8552 &sample, event); 8553 ret = perf_output_begin(&handle, &sample, event, 8554 cgroup_event->event_id.header.size); 8555 if (ret) 8556 goto out; 8557 8558 perf_output_put(&handle, cgroup_event->event_id); 8559 __output_copy(&handle, cgroup_event->path, cgroup_event->path_size); 8560 8561 perf_event__output_id_sample(event, &handle, &sample); 8562 8563 perf_output_end(&handle); 8564 out: 8565 cgroup_event->event_id.header.size = header_size; 8566 } 8567 8568 static void perf_event_cgroup(struct cgroup *cgrp) 8569 { 8570 struct perf_cgroup_event cgroup_event; 8571 char path_enomem[16] = "//enomem"; 8572 char *pathname; 8573 size_t size; 8574 8575 if (!atomic_read(&nr_cgroup_events)) 8576 return; 8577 8578 cgroup_event = (struct perf_cgroup_event){ 8579 .event_id = { 8580 .header = { 8581 .type = PERF_RECORD_CGROUP, 8582 .misc = 0, 8583 .size = sizeof(cgroup_event.event_id), 8584 }, 8585 .id = cgroup_id(cgrp), 8586 }, 8587 }; 8588 8589 pathname = kmalloc(PATH_MAX, GFP_KERNEL); 8590 if (pathname == NULL) { 8591 cgroup_event.path = path_enomem; 8592 } else { 8593 /* just to be sure to have enough space for alignment */ 8594 cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64)); 8595 cgroup_event.path = pathname; 8596 } 8597 8598 /* 8599 * Since our buffer works in 8 byte units we need to align our string 8600 * size to a multiple of 8. However, we must guarantee the tail end is 8601 * zero'd out to avoid leaking random bits to userspace. 8602 */ 8603 size = strlen(cgroup_event.path) + 1; 8604 while (!IS_ALIGNED(size, sizeof(u64))) 8605 cgroup_event.path[size++] = '\0'; 8606 8607 cgroup_event.event_id.header.size += size; 8608 cgroup_event.path_size = size; 8609 8610 perf_iterate_sb(perf_event_cgroup_output, 8611 &cgroup_event, 8612 NULL); 8613 8614 kfree(pathname); 8615 } 8616 8617 #endif 8618 8619 /* 8620 * mmap tracking 8621 */ 8622 8623 struct perf_mmap_event { 8624 struct vm_area_struct *vma; 8625 8626 const char *file_name; 8627 int file_size; 8628 int maj, min; 8629 u64 ino; 8630 u64 ino_generation; 8631 u32 prot, flags; 8632 u8 build_id[BUILD_ID_SIZE_MAX]; 8633 u32 build_id_size; 8634 8635 struct { 8636 struct perf_event_header header; 8637 8638 u32 pid; 8639 u32 tid; 8640 u64 start; 8641 u64 len; 8642 u64 pgoff; 8643 } event_id; 8644 }; 8645 8646 static int perf_event_mmap_match(struct perf_event *event, 8647 void *data) 8648 { 8649 struct perf_mmap_event *mmap_event = data; 8650 struct vm_area_struct *vma = mmap_event->vma; 8651 int executable = vma->vm_flags & VM_EXEC; 8652 8653 return (!executable && event->attr.mmap_data) || 8654 (executable && (event->attr.mmap || event->attr.mmap2)); 8655 } 8656 8657 static void perf_event_mmap_output(struct perf_event *event, 8658 void *data) 8659 { 8660 struct perf_mmap_event *mmap_event = data; 8661 struct perf_output_handle handle; 8662 struct perf_sample_data sample; 8663 int size = mmap_event->event_id.header.size; 8664 u32 type = mmap_event->event_id.header.type; 8665 bool use_build_id; 8666 int ret; 8667 8668 if (!perf_event_mmap_match(event, data)) 8669 return; 8670 8671 if (event->attr.mmap2) { 8672 mmap_event->event_id.header.type = PERF_RECORD_MMAP2; 8673 mmap_event->event_id.header.size += sizeof(mmap_event->maj); 8674 mmap_event->event_id.header.size += sizeof(mmap_event->min); 8675 mmap_event->event_id.header.size += sizeof(mmap_event->ino); 8676 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation); 8677 mmap_event->event_id.header.size += sizeof(mmap_event->prot); 8678 mmap_event->event_id.header.size += sizeof(mmap_event->flags); 8679 } 8680 8681 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event); 8682 ret = perf_output_begin(&handle, &sample, event, 8683 mmap_event->event_id.header.size); 8684 if (ret) 8685 goto out; 8686 8687 mmap_event->event_id.pid = perf_event_pid(event, current); 8688 mmap_event->event_id.tid = perf_event_tid(event, current); 8689 8690 use_build_id = event->attr.build_id && mmap_event->build_id_size; 8691 8692 if (event->attr.mmap2 && use_build_id) 8693 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID; 8694 8695 perf_output_put(&handle, mmap_event->event_id); 8696 8697 if (event->attr.mmap2) { 8698 if (use_build_id) { 8699 u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 }; 8700 8701 __output_copy(&handle, size, 4); 8702 __output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX); 8703 } else { 8704 perf_output_put(&handle, mmap_event->maj); 8705 perf_output_put(&handle, mmap_event->min); 8706 perf_output_put(&handle, mmap_event->ino); 8707 perf_output_put(&handle, mmap_event->ino_generation); 8708 } 8709 perf_output_put(&handle, mmap_event->prot); 8710 perf_output_put(&handle, mmap_event->flags); 8711 } 8712 8713 __output_copy(&handle, mmap_event->file_name, 8714 mmap_event->file_size); 8715 8716 perf_event__output_id_sample(event, &handle, &sample); 8717 8718 perf_output_end(&handle); 8719 out: 8720 mmap_event->event_id.header.size = size; 8721 mmap_event->event_id.header.type = type; 8722 } 8723 8724 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) 8725 { 8726 struct vm_area_struct *vma = mmap_event->vma; 8727 struct file *file = vma->vm_file; 8728 int maj = 0, min = 0; 8729 u64 ino = 0, gen = 0; 8730 u32 prot = 0, flags = 0; 8731 unsigned int size; 8732 char tmp[16]; 8733 char *buf = NULL; 8734 char *name = NULL; 8735 8736 if (vma->vm_flags & VM_READ) 8737 prot |= PROT_READ; 8738 if (vma->vm_flags & VM_WRITE) 8739 prot |= PROT_WRITE; 8740 if (vma->vm_flags & VM_EXEC) 8741 prot |= PROT_EXEC; 8742 8743 if (vma->vm_flags & VM_MAYSHARE) 8744 flags = MAP_SHARED; 8745 else 8746 flags = MAP_PRIVATE; 8747 8748 if (vma->vm_flags & VM_LOCKED) 8749 flags |= MAP_LOCKED; 8750 if (is_vm_hugetlb_page(vma)) 8751 flags |= MAP_HUGETLB; 8752 8753 if (file) { 8754 struct inode *inode; 8755 dev_t dev; 8756 8757 buf = kmalloc(PATH_MAX, GFP_KERNEL); 8758 if (!buf) { 8759 name = "//enomem"; 8760 goto cpy_name; 8761 } 8762 /* 8763 * d_path() works from the end of the rb backwards, so we 8764 * need to add enough zero bytes after the string to handle 8765 * the 64bit alignment we do later. 8766 */ 8767 name = file_path(file, buf, PATH_MAX - sizeof(u64)); 8768 if (IS_ERR(name)) { 8769 name = "//toolong"; 8770 goto cpy_name; 8771 } 8772 inode = file_inode(vma->vm_file); 8773 dev = inode->i_sb->s_dev; 8774 ino = inode->i_ino; 8775 gen = inode->i_generation; 8776 maj = MAJOR(dev); 8777 min = MINOR(dev); 8778 8779 goto got_name; 8780 } else { 8781 if (vma->vm_ops && vma->vm_ops->name) 8782 name = (char *) vma->vm_ops->name(vma); 8783 if (!name) 8784 name = (char *)arch_vma_name(vma); 8785 if (!name) { 8786 if (vma_is_initial_heap(vma)) 8787 name = "[heap]"; 8788 else if (vma_is_initial_stack(vma)) 8789 name = "[stack]"; 8790 else 8791 name = "//anon"; 8792 } 8793 } 8794 8795 cpy_name: 8796 strscpy(tmp, name, sizeof(tmp)); 8797 name = tmp; 8798 got_name: 8799 /* 8800 * Since our buffer works in 8 byte units we need to align our string 8801 * size to a multiple of 8. However, we must guarantee the tail end is 8802 * zero'd out to avoid leaking random bits to userspace. 8803 */ 8804 size = strlen(name)+1; 8805 while (!IS_ALIGNED(size, sizeof(u64))) 8806 name[size++] = '\0'; 8807 8808 mmap_event->file_name = name; 8809 mmap_event->file_size = size; 8810 mmap_event->maj = maj; 8811 mmap_event->min = min; 8812 mmap_event->ino = ino; 8813 mmap_event->ino_generation = gen; 8814 mmap_event->prot = prot; 8815 mmap_event->flags = flags; 8816 8817 if (!(vma->vm_flags & VM_EXEC)) 8818 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA; 8819 8820 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size; 8821 8822 if (atomic_read(&nr_build_id_events)) 8823 build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size); 8824 8825 perf_iterate_sb(perf_event_mmap_output, 8826 mmap_event, 8827 NULL); 8828 8829 kfree(buf); 8830 } 8831 8832 /* 8833 * Check whether inode and address range match filter criteria. 8834 */ 8835 static bool perf_addr_filter_match(struct perf_addr_filter *filter, 8836 struct file *file, unsigned long offset, 8837 unsigned long size) 8838 { 8839 /* d_inode(NULL) won't be equal to any mapped user-space file */ 8840 if (!filter->path.dentry) 8841 return false; 8842 8843 if (d_inode(filter->path.dentry) != file_inode(file)) 8844 return false; 8845 8846 if (filter->offset > offset + size) 8847 return false; 8848 8849 if (filter->offset + filter->size < offset) 8850 return false; 8851 8852 return true; 8853 } 8854 8855 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter, 8856 struct vm_area_struct *vma, 8857 struct perf_addr_filter_range *fr) 8858 { 8859 unsigned long vma_size = vma->vm_end - vma->vm_start; 8860 unsigned long off = vma->vm_pgoff << PAGE_SHIFT; 8861 struct file *file = vma->vm_file; 8862 8863 if (!perf_addr_filter_match(filter, file, off, vma_size)) 8864 return false; 8865 8866 if (filter->offset < off) { 8867 fr->start = vma->vm_start; 8868 fr->size = min(vma_size, filter->size - (off - filter->offset)); 8869 } else { 8870 fr->start = vma->vm_start + filter->offset - off; 8871 fr->size = min(vma->vm_end - fr->start, filter->size); 8872 } 8873 8874 return true; 8875 } 8876 8877 static void __perf_addr_filters_adjust(struct perf_event *event, void *data) 8878 { 8879 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 8880 struct vm_area_struct *vma = data; 8881 struct perf_addr_filter *filter; 8882 unsigned int restart = 0, count = 0; 8883 unsigned long flags; 8884 8885 if (!has_addr_filter(event)) 8886 return; 8887 8888 if (!vma->vm_file) 8889 return; 8890 8891 raw_spin_lock_irqsave(&ifh->lock, flags); 8892 list_for_each_entry(filter, &ifh->list, entry) { 8893 if (perf_addr_filter_vma_adjust(filter, vma, 8894 &event->addr_filter_ranges[count])) 8895 restart++; 8896 8897 count++; 8898 } 8899 8900 if (restart) 8901 event->addr_filters_gen++; 8902 raw_spin_unlock_irqrestore(&ifh->lock, flags); 8903 8904 if (restart) 8905 perf_event_stop(event, 1); 8906 } 8907 8908 /* 8909 * Adjust all task's events' filters to the new vma 8910 */ 8911 static void perf_addr_filters_adjust(struct vm_area_struct *vma) 8912 { 8913 struct perf_event_context *ctx; 8914 8915 /* 8916 * Data tracing isn't supported yet and as such there is no need 8917 * to keep track of anything that isn't related to executable code: 8918 */ 8919 if (!(vma->vm_flags & VM_EXEC)) 8920 return; 8921 8922 rcu_read_lock(); 8923 ctx = rcu_dereference(current->perf_event_ctxp); 8924 if (ctx) 8925 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true); 8926 rcu_read_unlock(); 8927 } 8928 8929 void perf_event_mmap(struct vm_area_struct *vma) 8930 { 8931 struct perf_mmap_event mmap_event; 8932 8933 if (!atomic_read(&nr_mmap_events)) 8934 return; 8935 8936 mmap_event = (struct perf_mmap_event){ 8937 .vma = vma, 8938 /* .file_name */ 8939 /* .file_size */ 8940 .event_id = { 8941 .header = { 8942 .type = PERF_RECORD_MMAP, 8943 .misc = PERF_RECORD_MISC_USER, 8944 /* .size */ 8945 }, 8946 /* .pid */ 8947 /* .tid */ 8948 .start = vma->vm_start, 8949 .len = vma->vm_end - vma->vm_start, 8950 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT, 8951 }, 8952 /* .maj (attr_mmap2 only) */ 8953 /* .min (attr_mmap2 only) */ 8954 /* .ino (attr_mmap2 only) */ 8955 /* .ino_generation (attr_mmap2 only) */ 8956 /* .prot (attr_mmap2 only) */ 8957 /* .flags (attr_mmap2 only) */ 8958 }; 8959 8960 perf_addr_filters_adjust(vma); 8961 perf_event_mmap_event(&mmap_event); 8962 } 8963 8964 void perf_event_aux_event(struct perf_event *event, unsigned long head, 8965 unsigned long size, u64 flags) 8966 { 8967 struct perf_output_handle handle; 8968 struct perf_sample_data sample; 8969 struct perf_aux_event { 8970 struct perf_event_header header; 8971 u64 offset; 8972 u64 size; 8973 u64 flags; 8974 } rec = { 8975 .header = { 8976 .type = PERF_RECORD_AUX, 8977 .misc = 0, 8978 .size = sizeof(rec), 8979 }, 8980 .offset = head, 8981 .size = size, 8982 .flags = flags, 8983 }; 8984 int ret; 8985 8986 perf_event_header__init_id(&rec.header, &sample, event); 8987 ret = perf_output_begin(&handle, &sample, event, rec.header.size); 8988 8989 if (ret) 8990 return; 8991 8992 perf_output_put(&handle, rec); 8993 perf_event__output_id_sample(event, &handle, &sample); 8994 8995 perf_output_end(&handle); 8996 } 8997 8998 /* 8999 * Lost/dropped samples logging 9000 */ 9001 void perf_log_lost_samples(struct perf_event *event, u64 lost) 9002 { 9003 struct perf_output_handle handle; 9004 struct perf_sample_data sample; 9005 int ret; 9006 9007 struct { 9008 struct perf_event_header header; 9009 u64 lost; 9010 } lost_samples_event = { 9011 .header = { 9012 .type = PERF_RECORD_LOST_SAMPLES, 9013 .misc = 0, 9014 .size = sizeof(lost_samples_event), 9015 }, 9016 .lost = lost, 9017 }; 9018 9019 perf_event_header__init_id(&lost_samples_event.header, &sample, event); 9020 9021 ret = perf_output_begin(&handle, &sample, event, 9022 lost_samples_event.header.size); 9023 if (ret) 9024 return; 9025 9026 perf_output_put(&handle, lost_samples_event); 9027 perf_event__output_id_sample(event, &handle, &sample); 9028 perf_output_end(&handle); 9029 } 9030 9031 /* 9032 * context_switch tracking 9033 */ 9034 9035 struct perf_switch_event { 9036 struct task_struct *task; 9037 struct task_struct *next_prev; 9038 9039 struct { 9040 struct perf_event_header header; 9041 u32 next_prev_pid; 9042 u32 next_prev_tid; 9043 } event_id; 9044 }; 9045 9046 static int perf_event_switch_match(struct perf_event *event) 9047 { 9048 return event->attr.context_switch; 9049 } 9050 9051 static void perf_event_switch_output(struct perf_event *event, void *data) 9052 { 9053 struct perf_switch_event *se = data; 9054 struct perf_output_handle handle; 9055 struct perf_sample_data sample; 9056 int ret; 9057 9058 if (!perf_event_switch_match(event)) 9059 return; 9060 9061 /* Only CPU-wide events are allowed to see next/prev pid/tid */ 9062 if (event->ctx->task) { 9063 se->event_id.header.type = PERF_RECORD_SWITCH; 9064 se->event_id.header.size = sizeof(se->event_id.header); 9065 } else { 9066 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE; 9067 se->event_id.header.size = sizeof(se->event_id); 9068 se->event_id.next_prev_pid = 9069 perf_event_pid(event, se->next_prev); 9070 se->event_id.next_prev_tid = 9071 perf_event_tid(event, se->next_prev); 9072 } 9073 9074 perf_event_header__init_id(&se->event_id.header, &sample, event); 9075 9076 ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size); 9077 if (ret) 9078 return; 9079 9080 if (event->ctx->task) 9081 perf_output_put(&handle, se->event_id.header); 9082 else 9083 perf_output_put(&handle, se->event_id); 9084 9085 perf_event__output_id_sample(event, &handle, &sample); 9086 9087 perf_output_end(&handle); 9088 } 9089 9090 static void perf_event_switch(struct task_struct *task, 9091 struct task_struct *next_prev, bool sched_in) 9092 { 9093 struct perf_switch_event switch_event; 9094 9095 /* N.B. caller checks nr_switch_events != 0 */ 9096 9097 switch_event = (struct perf_switch_event){ 9098 .task = task, 9099 .next_prev = next_prev, 9100 .event_id = { 9101 .header = { 9102 /* .type */ 9103 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT, 9104 /* .size */ 9105 }, 9106 /* .next_prev_pid */ 9107 /* .next_prev_tid */ 9108 }, 9109 }; 9110 9111 if (!sched_in && task->on_rq) { 9112 switch_event.event_id.header.misc |= 9113 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT; 9114 } 9115 9116 perf_iterate_sb(perf_event_switch_output, &switch_event, NULL); 9117 } 9118 9119 /* 9120 * IRQ throttle logging 9121 */ 9122 9123 static void perf_log_throttle(struct perf_event *event, int enable) 9124 { 9125 struct perf_output_handle handle; 9126 struct perf_sample_data sample; 9127 int ret; 9128 9129 struct { 9130 struct perf_event_header header; 9131 u64 time; 9132 u64 id; 9133 u64 stream_id; 9134 } throttle_event = { 9135 .header = { 9136 .type = PERF_RECORD_THROTTLE, 9137 .misc = 0, 9138 .size = sizeof(throttle_event), 9139 }, 9140 .time = perf_event_clock(event), 9141 .id = primary_event_id(event), 9142 .stream_id = event->id, 9143 }; 9144 9145 if (enable) 9146 throttle_event.header.type = PERF_RECORD_UNTHROTTLE; 9147 9148 perf_event_header__init_id(&throttle_event.header, &sample, event); 9149 9150 ret = perf_output_begin(&handle, &sample, event, 9151 throttle_event.header.size); 9152 if (ret) 9153 return; 9154 9155 perf_output_put(&handle, throttle_event); 9156 perf_event__output_id_sample(event, &handle, &sample); 9157 perf_output_end(&handle); 9158 } 9159 9160 /* 9161 * ksymbol register/unregister tracking 9162 */ 9163 9164 struct perf_ksymbol_event { 9165 const char *name; 9166 int name_len; 9167 struct { 9168 struct perf_event_header header; 9169 u64 addr; 9170 u32 len; 9171 u16 ksym_type; 9172 u16 flags; 9173 } event_id; 9174 }; 9175 9176 static int perf_event_ksymbol_match(struct perf_event *event) 9177 { 9178 return event->attr.ksymbol; 9179 } 9180 9181 static void perf_event_ksymbol_output(struct perf_event *event, void *data) 9182 { 9183 struct perf_ksymbol_event *ksymbol_event = data; 9184 struct perf_output_handle handle; 9185 struct perf_sample_data sample; 9186 int ret; 9187 9188 if (!perf_event_ksymbol_match(event)) 9189 return; 9190 9191 perf_event_header__init_id(&ksymbol_event->event_id.header, 9192 &sample, event); 9193 ret = perf_output_begin(&handle, &sample, event, 9194 ksymbol_event->event_id.header.size); 9195 if (ret) 9196 return; 9197 9198 perf_output_put(&handle, ksymbol_event->event_id); 9199 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len); 9200 perf_event__output_id_sample(event, &handle, &sample); 9201 9202 perf_output_end(&handle); 9203 } 9204 9205 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister, 9206 const char *sym) 9207 { 9208 struct perf_ksymbol_event ksymbol_event; 9209 char name[KSYM_NAME_LEN]; 9210 u16 flags = 0; 9211 int name_len; 9212 9213 if (!atomic_read(&nr_ksymbol_events)) 9214 return; 9215 9216 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX || 9217 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN) 9218 goto err; 9219 9220 strscpy(name, sym, KSYM_NAME_LEN); 9221 name_len = strlen(name) + 1; 9222 while (!IS_ALIGNED(name_len, sizeof(u64))) 9223 name[name_len++] = '\0'; 9224 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64)); 9225 9226 if (unregister) 9227 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER; 9228 9229 ksymbol_event = (struct perf_ksymbol_event){ 9230 .name = name, 9231 .name_len = name_len, 9232 .event_id = { 9233 .header = { 9234 .type = PERF_RECORD_KSYMBOL, 9235 .size = sizeof(ksymbol_event.event_id) + 9236 name_len, 9237 }, 9238 .addr = addr, 9239 .len = len, 9240 .ksym_type = ksym_type, 9241 .flags = flags, 9242 }, 9243 }; 9244 9245 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL); 9246 return; 9247 err: 9248 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type); 9249 } 9250 9251 /* 9252 * bpf program load/unload tracking 9253 */ 9254 9255 struct perf_bpf_event { 9256 struct bpf_prog *prog; 9257 struct { 9258 struct perf_event_header header; 9259 u16 type; 9260 u16 flags; 9261 u32 id; 9262 u8 tag[BPF_TAG_SIZE]; 9263 } event_id; 9264 }; 9265 9266 static int perf_event_bpf_match(struct perf_event *event) 9267 { 9268 return event->attr.bpf_event; 9269 } 9270 9271 static void perf_event_bpf_output(struct perf_event *event, void *data) 9272 { 9273 struct perf_bpf_event *bpf_event = data; 9274 struct perf_output_handle handle; 9275 struct perf_sample_data sample; 9276 int ret; 9277 9278 if (!perf_event_bpf_match(event)) 9279 return; 9280 9281 perf_event_header__init_id(&bpf_event->event_id.header, 9282 &sample, event); 9283 ret = perf_output_begin(&handle, &sample, event, 9284 bpf_event->event_id.header.size); 9285 if (ret) 9286 return; 9287 9288 perf_output_put(&handle, bpf_event->event_id); 9289 perf_event__output_id_sample(event, &handle, &sample); 9290 9291 perf_output_end(&handle); 9292 } 9293 9294 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog, 9295 enum perf_bpf_event_type type) 9296 { 9297 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD; 9298 int i; 9299 9300 if (prog->aux->func_cnt == 0) { 9301 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF, 9302 (u64)(unsigned long)prog->bpf_func, 9303 prog->jited_len, unregister, 9304 prog->aux->ksym.name); 9305 } else { 9306 for (i = 0; i < prog->aux->func_cnt; i++) { 9307 struct bpf_prog *subprog = prog->aux->func[i]; 9308 9309 perf_event_ksymbol( 9310 PERF_RECORD_KSYMBOL_TYPE_BPF, 9311 (u64)(unsigned long)subprog->bpf_func, 9312 subprog->jited_len, unregister, 9313 subprog->aux->ksym.name); 9314 } 9315 } 9316 } 9317 9318 void perf_event_bpf_event(struct bpf_prog *prog, 9319 enum perf_bpf_event_type type, 9320 u16 flags) 9321 { 9322 struct perf_bpf_event bpf_event; 9323 9324 switch (type) { 9325 case PERF_BPF_EVENT_PROG_LOAD: 9326 case PERF_BPF_EVENT_PROG_UNLOAD: 9327 if (atomic_read(&nr_ksymbol_events)) 9328 perf_event_bpf_emit_ksymbols(prog, type); 9329 break; 9330 default: 9331 return; 9332 } 9333 9334 if (!atomic_read(&nr_bpf_events)) 9335 return; 9336 9337 bpf_event = (struct perf_bpf_event){ 9338 .prog = prog, 9339 .event_id = { 9340 .header = { 9341 .type = PERF_RECORD_BPF_EVENT, 9342 .size = sizeof(bpf_event.event_id), 9343 }, 9344 .type = type, 9345 .flags = flags, 9346 .id = prog->aux->id, 9347 }, 9348 }; 9349 9350 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64)); 9351 9352 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE); 9353 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL); 9354 } 9355 9356 struct perf_text_poke_event { 9357 const void *old_bytes; 9358 const void *new_bytes; 9359 size_t pad; 9360 u16 old_len; 9361 u16 new_len; 9362 9363 struct { 9364 struct perf_event_header header; 9365 9366 u64 addr; 9367 } event_id; 9368 }; 9369 9370 static int perf_event_text_poke_match(struct perf_event *event) 9371 { 9372 return event->attr.text_poke; 9373 } 9374 9375 static void perf_event_text_poke_output(struct perf_event *event, void *data) 9376 { 9377 struct perf_text_poke_event *text_poke_event = data; 9378 struct perf_output_handle handle; 9379 struct perf_sample_data sample; 9380 u64 padding = 0; 9381 int ret; 9382 9383 if (!perf_event_text_poke_match(event)) 9384 return; 9385 9386 perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event); 9387 9388 ret = perf_output_begin(&handle, &sample, event, 9389 text_poke_event->event_id.header.size); 9390 if (ret) 9391 return; 9392 9393 perf_output_put(&handle, text_poke_event->event_id); 9394 perf_output_put(&handle, text_poke_event->old_len); 9395 perf_output_put(&handle, text_poke_event->new_len); 9396 9397 __output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len); 9398 __output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len); 9399 9400 if (text_poke_event->pad) 9401 __output_copy(&handle, &padding, text_poke_event->pad); 9402 9403 perf_event__output_id_sample(event, &handle, &sample); 9404 9405 perf_output_end(&handle); 9406 } 9407 9408 void perf_event_text_poke(const void *addr, const void *old_bytes, 9409 size_t old_len, const void *new_bytes, size_t new_len) 9410 { 9411 struct perf_text_poke_event text_poke_event; 9412 size_t tot, pad; 9413 9414 if (!atomic_read(&nr_text_poke_events)) 9415 return; 9416 9417 tot = sizeof(text_poke_event.old_len) + old_len; 9418 tot += sizeof(text_poke_event.new_len) + new_len; 9419 pad = ALIGN(tot, sizeof(u64)) - tot; 9420 9421 text_poke_event = (struct perf_text_poke_event){ 9422 .old_bytes = old_bytes, 9423 .new_bytes = new_bytes, 9424 .pad = pad, 9425 .old_len = old_len, 9426 .new_len = new_len, 9427 .event_id = { 9428 .header = { 9429 .type = PERF_RECORD_TEXT_POKE, 9430 .misc = PERF_RECORD_MISC_KERNEL, 9431 .size = sizeof(text_poke_event.event_id) + tot + pad, 9432 }, 9433 .addr = (unsigned long)addr, 9434 }, 9435 }; 9436 9437 perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL); 9438 } 9439 9440 void perf_event_itrace_started(struct perf_event *event) 9441 { 9442 event->attach_state |= PERF_ATTACH_ITRACE; 9443 } 9444 9445 static void perf_log_itrace_start(struct perf_event *event) 9446 { 9447 struct perf_output_handle handle; 9448 struct perf_sample_data sample; 9449 struct perf_aux_event { 9450 struct perf_event_header header; 9451 u32 pid; 9452 u32 tid; 9453 } rec; 9454 int ret; 9455 9456 if (event->parent) 9457 event = event->parent; 9458 9459 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) || 9460 event->attach_state & PERF_ATTACH_ITRACE) 9461 return; 9462 9463 rec.header.type = PERF_RECORD_ITRACE_START; 9464 rec.header.misc = 0; 9465 rec.header.size = sizeof(rec); 9466 rec.pid = perf_event_pid(event, current); 9467 rec.tid = perf_event_tid(event, current); 9468 9469 perf_event_header__init_id(&rec.header, &sample, event); 9470 ret = perf_output_begin(&handle, &sample, event, rec.header.size); 9471 9472 if (ret) 9473 return; 9474 9475 perf_output_put(&handle, rec); 9476 perf_event__output_id_sample(event, &handle, &sample); 9477 9478 perf_output_end(&handle); 9479 } 9480 9481 void perf_report_aux_output_id(struct perf_event *event, u64 hw_id) 9482 { 9483 struct perf_output_handle handle; 9484 struct perf_sample_data sample; 9485 struct perf_aux_event { 9486 struct perf_event_header header; 9487 u64 hw_id; 9488 } rec; 9489 int ret; 9490 9491 if (event->parent) 9492 event = event->parent; 9493 9494 rec.header.type = PERF_RECORD_AUX_OUTPUT_HW_ID; 9495 rec.header.misc = 0; 9496 rec.header.size = sizeof(rec); 9497 rec.hw_id = hw_id; 9498 9499 perf_event_header__init_id(&rec.header, &sample, event); 9500 ret = perf_output_begin(&handle, &sample, event, rec.header.size); 9501 9502 if (ret) 9503 return; 9504 9505 perf_output_put(&handle, rec); 9506 perf_event__output_id_sample(event, &handle, &sample); 9507 9508 perf_output_end(&handle); 9509 } 9510 EXPORT_SYMBOL_GPL(perf_report_aux_output_id); 9511 9512 static int 9513 __perf_event_account_interrupt(struct perf_event *event, int throttle) 9514 { 9515 struct hw_perf_event *hwc = &event->hw; 9516 int ret = 0; 9517 u64 seq; 9518 9519 seq = __this_cpu_read(perf_throttled_seq); 9520 if (seq != hwc->interrupts_seq) { 9521 hwc->interrupts_seq = seq; 9522 hwc->interrupts = 1; 9523 } else { 9524 hwc->interrupts++; 9525 if (unlikely(throttle && 9526 hwc->interrupts > max_samples_per_tick)) { 9527 __this_cpu_inc(perf_throttled_count); 9528 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); 9529 hwc->interrupts = MAX_INTERRUPTS; 9530 perf_log_throttle(event, 0); 9531 ret = 1; 9532 } 9533 } 9534 9535 if (event->attr.freq) { 9536 u64 now = perf_clock(); 9537 s64 delta = now - hwc->freq_time_stamp; 9538 9539 hwc->freq_time_stamp = now; 9540 9541 if (delta > 0 && delta < 2*TICK_NSEC) 9542 perf_adjust_period(event, delta, hwc->last_period, true); 9543 } 9544 9545 return ret; 9546 } 9547 9548 int perf_event_account_interrupt(struct perf_event *event) 9549 { 9550 return __perf_event_account_interrupt(event, 1); 9551 } 9552 9553 static inline bool sample_is_allowed(struct perf_event *event, struct pt_regs *regs) 9554 { 9555 /* 9556 * Due to interrupt latency (AKA "skid"), we may enter the 9557 * kernel before taking an overflow, even if the PMU is only 9558 * counting user events. 9559 */ 9560 if (event->attr.exclude_kernel && !user_mode(regs)) 9561 return false; 9562 9563 return true; 9564 } 9565 9566 #ifdef CONFIG_BPF_SYSCALL 9567 static void bpf_overflow_handler(struct perf_event *event, 9568 struct perf_sample_data *data, 9569 struct pt_regs *regs) 9570 { 9571 struct bpf_perf_event_data_kern ctx = { 9572 .data = data, 9573 .event = event, 9574 }; 9575 struct bpf_prog *prog; 9576 int ret = 0; 9577 9578 ctx.regs = perf_arch_bpf_user_pt_regs(regs); 9579 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) 9580 goto out; 9581 rcu_read_lock(); 9582 prog = READ_ONCE(event->prog); 9583 if (prog) { 9584 perf_prepare_sample(data, event, regs); 9585 ret = bpf_prog_run(prog, &ctx); 9586 } 9587 rcu_read_unlock(); 9588 out: 9589 __this_cpu_dec(bpf_prog_active); 9590 if (!ret) 9591 return; 9592 9593 event->orig_overflow_handler(event, data, regs); 9594 } 9595 9596 static int perf_event_set_bpf_handler(struct perf_event *event, 9597 struct bpf_prog *prog, 9598 u64 bpf_cookie) 9599 { 9600 if (event->overflow_handler_context) 9601 /* hw breakpoint or kernel counter */ 9602 return -EINVAL; 9603 9604 if (event->prog) 9605 return -EEXIST; 9606 9607 if (prog->type != BPF_PROG_TYPE_PERF_EVENT) 9608 return -EINVAL; 9609 9610 if (event->attr.precise_ip && 9611 prog->call_get_stack && 9612 (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) || 9613 event->attr.exclude_callchain_kernel || 9614 event->attr.exclude_callchain_user)) { 9615 /* 9616 * On perf_event with precise_ip, calling bpf_get_stack() 9617 * may trigger unwinder warnings and occasional crashes. 9618 * bpf_get_[stack|stackid] works around this issue by using 9619 * callchain attached to perf_sample_data. If the 9620 * perf_event does not full (kernel and user) callchain 9621 * attached to perf_sample_data, do not allow attaching BPF 9622 * program that calls bpf_get_[stack|stackid]. 9623 */ 9624 return -EPROTO; 9625 } 9626 9627 event->prog = prog; 9628 event->bpf_cookie = bpf_cookie; 9629 event->orig_overflow_handler = READ_ONCE(event->overflow_handler); 9630 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler); 9631 return 0; 9632 } 9633 9634 static void perf_event_free_bpf_handler(struct perf_event *event) 9635 { 9636 struct bpf_prog *prog = event->prog; 9637 9638 if (!prog) 9639 return; 9640 9641 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler); 9642 event->prog = NULL; 9643 bpf_prog_put(prog); 9644 } 9645 #else 9646 static void bpf_overflow_handler(struct perf_event *event, 9647 struct perf_sample_data *data, 9648 struct pt_regs *regs) 9649 { 9650 } 9651 9652 static int perf_event_set_bpf_handler(struct perf_event *event, 9653 struct bpf_prog *prog, 9654 u64 bpf_cookie) 9655 { 9656 return -EOPNOTSUPP; 9657 } 9658 9659 static void perf_event_free_bpf_handler(struct perf_event *event) 9660 { 9661 } 9662 #endif 9663 9664 /* 9665 * Generic event overflow handling, sampling. 9666 */ 9667 9668 static int __perf_event_overflow(struct perf_event *event, 9669 int throttle, struct perf_sample_data *data, 9670 struct pt_regs *regs) 9671 { 9672 int events = atomic_read(&event->event_limit); 9673 int ret = 0; 9674 9675 /* 9676 * Non-sampling counters might still use the PMI to fold short 9677 * hardware counters, ignore those. 9678 */ 9679 if (unlikely(!is_sampling_event(event))) 9680 return 0; 9681 9682 ret = __perf_event_account_interrupt(event, throttle); 9683 9684 /* 9685 * XXX event_limit might not quite work as expected on inherited 9686 * events 9687 */ 9688 9689 event->pending_kill = POLL_IN; 9690 if (events && atomic_dec_and_test(&event->event_limit)) { 9691 ret = 1; 9692 event->pending_kill = POLL_HUP; 9693 perf_event_disable_inatomic(event); 9694 } 9695 9696 if (event->attr.sigtrap) { 9697 /* 9698 * The desired behaviour of sigtrap vs invalid samples is a bit 9699 * tricky; on the one hand, one should not loose the SIGTRAP if 9700 * it is the first event, on the other hand, we should also not 9701 * trigger the WARN or override the data address. 9702 */ 9703 bool valid_sample = sample_is_allowed(event, regs); 9704 unsigned int pending_id = 1; 9705 9706 if (regs) 9707 pending_id = hash32_ptr((void *)instruction_pointer(regs)) ?: 1; 9708 if (!event->pending_sigtrap) { 9709 event->pending_sigtrap = pending_id; 9710 local_inc(&event->ctx->nr_pending); 9711 } else if (event->attr.exclude_kernel && valid_sample) { 9712 /* 9713 * Should not be able to return to user space without 9714 * consuming pending_sigtrap; with exceptions: 9715 * 9716 * 1. Where !exclude_kernel, events can overflow again 9717 * in the kernel without returning to user space. 9718 * 9719 * 2. Events that can overflow again before the IRQ- 9720 * work without user space progress (e.g. hrtimer). 9721 * To approximate progress (with false negatives), 9722 * check 32-bit hash of the current IP. 9723 */ 9724 WARN_ON_ONCE(event->pending_sigtrap != pending_id); 9725 } 9726 9727 event->pending_addr = 0; 9728 if (valid_sample && (data->sample_flags & PERF_SAMPLE_ADDR)) 9729 event->pending_addr = data->addr; 9730 irq_work_queue(&event->pending_irq); 9731 } 9732 9733 READ_ONCE(event->overflow_handler)(event, data, regs); 9734 9735 if (*perf_event_fasync(event) && event->pending_kill) { 9736 event->pending_wakeup = 1; 9737 irq_work_queue(&event->pending_irq); 9738 } 9739 9740 return ret; 9741 } 9742 9743 int perf_event_overflow(struct perf_event *event, 9744 struct perf_sample_data *data, 9745 struct pt_regs *regs) 9746 { 9747 return __perf_event_overflow(event, 1, data, regs); 9748 } 9749 9750 /* 9751 * Generic software event infrastructure 9752 */ 9753 9754 struct swevent_htable { 9755 struct swevent_hlist *swevent_hlist; 9756 struct mutex hlist_mutex; 9757 int hlist_refcount; 9758 9759 /* Recursion avoidance in each contexts */ 9760 int recursion[PERF_NR_CONTEXTS]; 9761 }; 9762 9763 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable); 9764 9765 /* 9766 * We directly increment event->count and keep a second value in 9767 * event->hw.period_left to count intervals. This period event 9768 * is kept in the range [-sample_period, 0] so that we can use the 9769 * sign as trigger. 9770 */ 9771 9772 u64 perf_swevent_set_period(struct perf_event *event) 9773 { 9774 struct hw_perf_event *hwc = &event->hw; 9775 u64 period = hwc->last_period; 9776 u64 nr, offset; 9777 s64 old, val; 9778 9779 hwc->last_period = hwc->sample_period; 9780 9781 old = local64_read(&hwc->period_left); 9782 do { 9783 val = old; 9784 if (val < 0) 9785 return 0; 9786 9787 nr = div64_u64(period + val, period); 9788 offset = nr * period; 9789 val -= offset; 9790 } while (!local64_try_cmpxchg(&hwc->period_left, &old, val)); 9791 9792 return nr; 9793 } 9794 9795 static void perf_swevent_overflow(struct perf_event *event, u64 overflow, 9796 struct perf_sample_data *data, 9797 struct pt_regs *regs) 9798 { 9799 struct hw_perf_event *hwc = &event->hw; 9800 int throttle = 0; 9801 9802 if (!overflow) 9803 overflow = perf_swevent_set_period(event); 9804 9805 if (hwc->interrupts == MAX_INTERRUPTS) 9806 return; 9807 9808 for (; overflow; overflow--) { 9809 if (__perf_event_overflow(event, throttle, 9810 data, regs)) { 9811 /* 9812 * We inhibit the overflow from happening when 9813 * hwc->interrupts == MAX_INTERRUPTS. 9814 */ 9815 break; 9816 } 9817 throttle = 1; 9818 } 9819 } 9820 9821 static void perf_swevent_event(struct perf_event *event, u64 nr, 9822 struct perf_sample_data *data, 9823 struct pt_regs *regs) 9824 { 9825 struct hw_perf_event *hwc = &event->hw; 9826 9827 local64_add(nr, &event->count); 9828 9829 if (!regs) 9830 return; 9831 9832 if (!is_sampling_event(event)) 9833 return; 9834 9835 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) { 9836 data->period = nr; 9837 return perf_swevent_overflow(event, 1, data, regs); 9838 } else 9839 data->period = event->hw.last_period; 9840 9841 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq) 9842 return perf_swevent_overflow(event, 1, data, regs); 9843 9844 if (local64_add_negative(nr, &hwc->period_left)) 9845 return; 9846 9847 perf_swevent_overflow(event, 0, data, regs); 9848 } 9849 9850 static int perf_exclude_event(struct perf_event *event, 9851 struct pt_regs *regs) 9852 { 9853 if (event->hw.state & PERF_HES_STOPPED) 9854 return 1; 9855 9856 if (regs) { 9857 if (event->attr.exclude_user && user_mode(regs)) 9858 return 1; 9859 9860 if (event->attr.exclude_kernel && !user_mode(regs)) 9861 return 1; 9862 } 9863 9864 return 0; 9865 } 9866 9867 static int perf_swevent_match(struct perf_event *event, 9868 enum perf_type_id type, 9869 u32 event_id, 9870 struct perf_sample_data *data, 9871 struct pt_regs *regs) 9872 { 9873 if (event->attr.type != type) 9874 return 0; 9875 9876 if (event->attr.config != event_id) 9877 return 0; 9878 9879 if (perf_exclude_event(event, regs)) 9880 return 0; 9881 9882 return 1; 9883 } 9884 9885 static inline u64 swevent_hash(u64 type, u32 event_id) 9886 { 9887 u64 val = event_id | (type << 32); 9888 9889 return hash_64(val, SWEVENT_HLIST_BITS); 9890 } 9891 9892 static inline struct hlist_head * 9893 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id) 9894 { 9895 u64 hash = swevent_hash(type, event_id); 9896 9897 return &hlist->heads[hash]; 9898 } 9899 9900 /* For the read side: events when they trigger */ 9901 static inline struct hlist_head * 9902 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id) 9903 { 9904 struct swevent_hlist *hlist; 9905 9906 hlist = rcu_dereference(swhash->swevent_hlist); 9907 if (!hlist) 9908 return NULL; 9909 9910 return __find_swevent_head(hlist, type, event_id); 9911 } 9912 9913 /* For the event head insertion and removal in the hlist */ 9914 static inline struct hlist_head * 9915 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event) 9916 { 9917 struct swevent_hlist *hlist; 9918 u32 event_id = event->attr.config; 9919 u64 type = event->attr.type; 9920 9921 /* 9922 * Event scheduling is always serialized against hlist allocation 9923 * and release. Which makes the protected version suitable here. 9924 * The context lock guarantees that. 9925 */ 9926 hlist = rcu_dereference_protected(swhash->swevent_hlist, 9927 lockdep_is_held(&event->ctx->lock)); 9928 if (!hlist) 9929 return NULL; 9930 9931 return __find_swevent_head(hlist, type, event_id); 9932 } 9933 9934 static void do_perf_sw_event(enum perf_type_id type, u32 event_id, 9935 u64 nr, 9936 struct perf_sample_data *data, 9937 struct pt_regs *regs) 9938 { 9939 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 9940 struct perf_event *event; 9941 struct hlist_head *head; 9942 9943 rcu_read_lock(); 9944 head = find_swevent_head_rcu(swhash, type, event_id); 9945 if (!head) 9946 goto end; 9947 9948 hlist_for_each_entry_rcu(event, head, hlist_entry) { 9949 if (perf_swevent_match(event, type, event_id, data, regs)) 9950 perf_swevent_event(event, nr, data, regs); 9951 } 9952 end: 9953 rcu_read_unlock(); 9954 } 9955 9956 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]); 9957 9958 int perf_swevent_get_recursion_context(void) 9959 { 9960 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 9961 9962 return get_recursion_context(swhash->recursion); 9963 } 9964 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context); 9965 9966 void perf_swevent_put_recursion_context(int rctx) 9967 { 9968 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 9969 9970 put_recursion_context(swhash->recursion, rctx); 9971 } 9972 9973 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) 9974 { 9975 struct perf_sample_data data; 9976 9977 if (WARN_ON_ONCE(!regs)) 9978 return; 9979 9980 perf_sample_data_init(&data, addr, 0); 9981 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs); 9982 } 9983 9984 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) 9985 { 9986 int rctx; 9987 9988 preempt_disable_notrace(); 9989 rctx = perf_swevent_get_recursion_context(); 9990 if (unlikely(rctx < 0)) 9991 goto fail; 9992 9993 ___perf_sw_event(event_id, nr, regs, addr); 9994 9995 perf_swevent_put_recursion_context(rctx); 9996 fail: 9997 preempt_enable_notrace(); 9998 } 9999 10000 static void perf_swevent_read(struct perf_event *event) 10001 { 10002 } 10003 10004 static int perf_swevent_add(struct perf_event *event, int flags) 10005 { 10006 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 10007 struct hw_perf_event *hwc = &event->hw; 10008 struct hlist_head *head; 10009 10010 if (is_sampling_event(event)) { 10011 hwc->last_period = hwc->sample_period; 10012 perf_swevent_set_period(event); 10013 } 10014 10015 hwc->state = !(flags & PERF_EF_START); 10016 10017 head = find_swevent_head(swhash, event); 10018 if (WARN_ON_ONCE(!head)) 10019 return -EINVAL; 10020 10021 hlist_add_head_rcu(&event->hlist_entry, head); 10022 perf_event_update_userpage(event); 10023 10024 return 0; 10025 } 10026 10027 static void perf_swevent_del(struct perf_event *event, int flags) 10028 { 10029 hlist_del_rcu(&event->hlist_entry); 10030 } 10031 10032 static void perf_swevent_start(struct perf_event *event, int flags) 10033 { 10034 event->hw.state = 0; 10035 } 10036 10037 static void perf_swevent_stop(struct perf_event *event, int flags) 10038 { 10039 event->hw.state = PERF_HES_STOPPED; 10040 } 10041 10042 /* Deref the hlist from the update side */ 10043 static inline struct swevent_hlist * 10044 swevent_hlist_deref(struct swevent_htable *swhash) 10045 { 10046 return rcu_dereference_protected(swhash->swevent_hlist, 10047 lockdep_is_held(&swhash->hlist_mutex)); 10048 } 10049 10050 static void swevent_hlist_release(struct swevent_htable *swhash) 10051 { 10052 struct swevent_hlist *hlist = swevent_hlist_deref(swhash); 10053 10054 if (!hlist) 10055 return; 10056 10057 RCU_INIT_POINTER(swhash->swevent_hlist, NULL); 10058 kfree_rcu(hlist, rcu_head); 10059 } 10060 10061 static void swevent_hlist_put_cpu(int cpu) 10062 { 10063 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 10064 10065 mutex_lock(&swhash->hlist_mutex); 10066 10067 if (!--swhash->hlist_refcount) 10068 swevent_hlist_release(swhash); 10069 10070 mutex_unlock(&swhash->hlist_mutex); 10071 } 10072 10073 static void swevent_hlist_put(void) 10074 { 10075 int cpu; 10076 10077 for_each_possible_cpu(cpu) 10078 swevent_hlist_put_cpu(cpu); 10079 } 10080 10081 static int swevent_hlist_get_cpu(int cpu) 10082 { 10083 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 10084 int err = 0; 10085 10086 mutex_lock(&swhash->hlist_mutex); 10087 if (!swevent_hlist_deref(swhash) && 10088 cpumask_test_cpu(cpu, perf_online_mask)) { 10089 struct swevent_hlist *hlist; 10090 10091 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL); 10092 if (!hlist) { 10093 err = -ENOMEM; 10094 goto exit; 10095 } 10096 rcu_assign_pointer(swhash->swevent_hlist, hlist); 10097 } 10098 swhash->hlist_refcount++; 10099 exit: 10100 mutex_unlock(&swhash->hlist_mutex); 10101 10102 return err; 10103 } 10104 10105 static int swevent_hlist_get(void) 10106 { 10107 int err, cpu, failed_cpu; 10108 10109 mutex_lock(&pmus_lock); 10110 for_each_possible_cpu(cpu) { 10111 err = swevent_hlist_get_cpu(cpu); 10112 if (err) { 10113 failed_cpu = cpu; 10114 goto fail; 10115 } 10116 } 10117 mutex_unlock(&pmus_lock); 10118 return 0; 10119 fail: 10120 for_each_possible_cpu(cpu) { 10121 if (cpu == failed_cpu) 10122 break; 10123 swevent_hlist_put_cpu(cpu); 10124 } 10125 mutex_unlock(&pmus_lock); 10126 return err; 10127 } 10128 10129 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX]; 10130 10131 static void sw_perf_event_destroy(struct perf_event *event) 10132 { 10133 u64 event_id = event->attr.config; 10134 10135 WARN_ON(event->parent); 10136 10137 static_key_slow_dec(&perf_swevent_enabled[event_id]); 10138 swevent_hlist_put(); 10139 } 10140 10141 static struct pmu perf_cpu_clock; /* fwd declaration */ 10142 static struct pmu perf_task_clock; 10143 10144 static int perf_swevent_init(struct perf_event *event) 10145 { 10146 u64 event_id = event->attr.config; 10147 10148 if (event->attr.type != PERF_TYPE_SOFTWARE) 10149 return -ENOENT; 10150 10151 /* 10152 * no branch sampling for software events 10153 */ 10154 if (has_branch_stack(event)) 10155 return -EOPNOTSUPP; 10156 10157 switch (event_id) { 10158 case PERF_COUNT_SW_CPU_CLOCK: 10159 event->attr.type = perf_cpu_clock.type; 10160 return -ENOENT; 10161 case PERF_COUNT_SW_TASK_CLOCK: 10162 event->attr.type = perf_task_clock.type; 10163 return -ENOENT; 10164 10165 default: 10166 break; 10167 } 10168 10169 if (event_id >= PERF_COUNT_SW_MAX) 10170 return -ENOENT; 10171 10172 if (!event->parent) { 10173 int err; 10174 10175 err = swevent_hlist_get(); 10176 if (err) 10177 return err; 10178 10179 static_key_slow_inc(&perf_swevent_enabled[event_id]); 10180 event->destroy = sw_perf_event_destroy; 10181 } 10182 10183 return 0; 10184 } 10185 10186 static struct pmu perf_swevent = { 10187 .task_ctx_nr = perf_sw_context, 10188 10189 .capabilities = PERF_PMU_CAP_NO_NMI, 10190 10191 .event_init = perf_swevent_init, 10192 .add = perf_swevent_add, 10193 .del = perf_swevent_del, 10194 .start = perf_swevent_start, 10195 .stop = perf_swevent_stop, 10196 .read = perf_swevent_read, 10197 }; 10198 10199 #ifdef CONFIG_EVENT_TRACING 10200 10201 static void tp_perf_event_destroy(struct perf_event *event) 10202 { 10203 perf_trace_destroy(event); 10204 } 10205 10206 static int perf_tp_event_init(struct perf_event *event) 10207 { 10208 int err; 10209 10210 if (event->attr.type != PERF_TYPE_TRACEPOINT) 10211 return -ENOENT; 10212 10213 /* 10214 * no branch sampling for tracepoint events 10215 */ 10216 if (has_branch_stack(event)) 10217 return -EOPNOTSUPP; 10218 10219 err = perf_trace_init(event); 10220 if (err) 10221 return err; 10222 10223 event->destroy = tp_perf_event_destroy; 10224 10225 return 0; 10226 } 10227 10228 static struct pmu perf_tracepoint = { 10229 .task_ctx_nr = perf_sw_context, 10230 10231 .event_init = perf_tp_event_init, 10232 .add = perf_trace_add, 10233 .del = perf_trace_del, 10234 .start = perf_swevent_start, 10235 .stop = perf_swevent_stop, 10236 .read = perf_swevent_read, 10237 }; 10238 10239 static int perf_tp_filter_match(struct perf_event *event, 10240 struct perf_sample_data *data) 10241 { 10242 void *record = data->raw->frag.data; 10243 10244 /* only top level events have filters set */ 10245 if (event->parent) 10246 event = event->parent; 10247 10248 if (likely(!event->filter) || filter_match_preds(event->filter, record)) 10249 return 1; 10250 return 0; 10251 } 10252 10253 static int perf_tp_event_match(struct perf_event *event, 10254 struct perf_sample_data *data, 10255 struct pt_regs *regs) 10256 { 10257 if (event->hw.state & PERF_HES_STOPPED) 10258 return 0; 10259 /* 10260 * If exclude_kernel, only trace user-space tracepoints (uprobes) 10261 */ 10262 if (event->attr.exclude_kernel && !user_mode(regs)) 10263 return 0; 10264 10265 if (!perf_tp_filter_match(event, data)) 10266 return 0; 10267 10268 return 1; 10269 } 10270 10271 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx, 10272 struct trace_event_call *call, u64 count, 10273 struct pt_regs *regs, struct hlist_head *head, 10274 struct task_struct *task) 10275 { 10276 if (bpf_prog_array_valid(call)) { 10277 *(struct pt_regs **)raw_data = regs; 10278 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) { 10279 perf_swevent_put_recursion_context(rctx); 10280 return; 10281 } 10282 } 10283 perf_tp_event(call->event.type, count, raw_data, size, regs, head, 10284 rctx, task); 10285 } 10286 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit); 10287 10288 static void __perf_tp_event_target_task(u64 count, void *record, 10289 struct pt_regs *regs, 10290 struct perf_sample_data *data, 10291 struct perf_event *event) 10292 { 10293 struct trace_entry *entry = record; 10294 10295 if (event->attr.config != entry->type) 10296 return; 10297 /* Cannot deliver synchronous signal to other task. */ 10298 if (event->attr.sigtrap) 10299 return; 10300 if (perf_tp_event_match(event, data, regs)) 10301 perf_swevent_event(event, count, data, regs); 10302 } 10303 10304 static void perf_tp_event_target_task(u64 count, void *record, 10305 struct pt_regs *regs, 10306 struct perf_sample_data *data, 10307 struct perf_event_context *ctx) 10308 { 10309 unsigned int cpu = smp_processor_id(); 10310 struct pmu *pmu = &perf_tracepoint; 10311 struct perf_event *event, *sibling; 10312 10313 perf_event_groups_for_cpu_pmu(event, &ctx->pinned_groups, cpu, pmu) { 10314 __perf_tp_event_target_task(count, record, regs, data, event); 10315 for_each_sibling_event(sibling, event) 10316 __perf_tp_event_target_task(count, record, regs, data, sibling); 10317 } 10318 10319 perf_event_groups_for_cpu_pmu(event, &ctx->flexible_groups, cpu, pmu) { 10320 __perf_tp_event_target_task(count, record, regs, data, event); 10321 for_each_sibling_event(sibling, event) 10322 __perf_tp_event_target_task(count, record, regs, data, sibling); 10323 } 10324 } 10325 10326 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size, 10327 struct pt_regs *regs, struct hlist_head *head, int rctx, 10328 struct task_struct *task) 10329 { 10330 struct perf_sample_data data; 10331 struct perf_event *event; 10332 10333 struct perf_raw_record raw = { 10334 .frag = { 10335 .size = entry_size, 10336 .data = record, 10337 }, 10338 }; 10339 10340 perf_sample_data_init(&data, 0, 0); 10341 perf_sample_save_raw_data(&data, &raw); 10342 10343 perf_trace_buf_update(record, event_type); 10344 10345 hlist_for_each_entry_rcu(event, head, hlist_entry) { 10346 if (perf_tp_event_match(event, &data, regs)) { 10347 perf_swevent_event(event, count, &data, regs); 10348 10349 /* 10350 * Here use the same on-stack perf_sample_data, 10351 * some members in data are event-specific and 10352 * need to be re-computed for different sweveents. 10353 * Re-initialize data->sample_flags safely to avoid 10354 * the problem that next event skips preparing data 10355 * because data->sample_flags is set. 10356 */ 10357 perf_sample_data_init(&data, 0, 0); 10358 perf_sample_save_raw_data(&data, &raw); 10359 } 10360 } 10361 10362 /* 10363 * If we got specified a target task, also iterate its context and 10364 * deliver this event there too. 10365 */ 10366 if (task && task != current) { 10367 struct perf_event_context *ctx; 10368 10369 rcu_read_lock(); 10370 ctx = rcu_dereference(task->perf_event_ctxp); 10371 if (!ctx) 10372 goto unlock; 10373 10374 raw_spin_lock(&ctx->lock); 10375 perf_tp_event_target_task(count, record, regs, &data, ctx); 10376 raw_spin_unlock(&ctx->lock); 10377 unlock: 10378 rcu_read_unlock(); 10379 } 10380 10381 perf_swevent_put_recursion_context(rctx); 10382 } 10383 EXPORT_SYMBOL_GPL(perf_tp_event); 10384 10385 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS) 10386 /* 10387 * Flags in config, used by dynamic PMU kprobe and uprobe 10388 * The flags should match following PMU_FORMAT_ATTR(). 10389 * 10390 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe 10391 * if not set, create kprobe/uprobe 10392 * 10393 * The following values specify a reference counter (or semaphore in the 10394 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically 10395 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset. 10396 * 10397 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset 10398 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left 10399 */ 10400 enum perf_probe_config { 10401 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */ 10402 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32, 10403 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS, 10404 }; 10405 10406 PMU_FORMAT_ATTR(retprobe, "config:0"); 10407 #endif 10408 10409 #ifdef CONFIG_KPROBE_EVENTS 10410 static struct attribute *kprobe_attrs[] = { 10411 &format_attr_retprobe.attr, 10412 NULL, 10413 }; 10414 10415 static struct attribute_group kprobe_format_group = { 10416 .name = "format", 10417 .attrs = kprobe_attrs, 10418 }; 10419 10420 static const struct attribute_group *kprobe_attr_groups[] = { 10421 &kprobe_format_group, 10422 NULL, 10423 }; 10424 10425 static int perf_kprobe_event_init(struct perf_event *event); 10426 static struct pmu perf_kprobe = { 10427 .task_ctx_nr = perf_sw_context, 10428 .event_init = perf_kprobe_event_init, 10429 .add = perf_trace_add, 10430 .del = perf_trace_del, 10431 .start = perf_swevent_start, 10432 .stop = perf_swevent_stop, 10433 .read = perf_swevent_read, 10434 .attr_groups = kprobe_attr_groups, 10435 }; 10436 10437 static int perf_kprobe_event_init(struct perf_event *event) 10438 { 10439 int err; 10440 bool is_retprobe; 10441 10442 if (event->attr.type != perf_kprobe.type) 10443 return -ENOENT; 10444 10445 if (!perfmon_capable()) 10446 return -EACCES; 10447 10448 /* 10449 * no branch sampling for probe events 10450 */ 10451 if (has_branch_stack(event)) 10452 return -EOPNOTSUPP; 10453 10454 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE; 10455 err = perf_kprobe_init(event, is_retprobe); 10456 if (err) 10457 return err; 10458 10459 event->destroy = perf_kprobe_destroy; 10460 10461 return 0; 10462 } 10463 #endif /* CONFIG_KPROBE_EVENTS */ 10464 10465 #ifdef CONFIG_UPROBE_EVENTS 10466 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63"); 10467 10468 static struct attribute *uprobe_attrs[] = { 10469 &format_attr_retprobe.attr, 10470 &format_attr_ref_ctr_offset.attr, 10471 NULL, 10472 }; 10473 10474 static struct attribute_group uprobe_format_group = { 10475 .name = "format", 10476 .attrs = uprobe_attrs, 10477 }; 10478 10479 static const struct attribute_group *uprobe_attr_groups[] = { 10480 &uprobe_format_group, 10481 NULL, 10482 }; 10483 10484 static int perf_uprobe_event_init(struct perf_event *event); 10485 static struct pmu perf_uprobe = { 10486 .task_ctx_nr = perf_sw_context, 10487 .event_init = perf_uprobe_event_init, 10488 .add = perf_trace_add, 10489 .del = perf_trace_del, 10490 .start = perf_swevent_start, 10491 .stop = perf_swevent_stop, 10492 .read = perf_swevent_read, 10493 .attr_groups = uprobe_attr_groups, 10494 }; 10495 10496 static int perf_uprobe_event_init(struct perf_event *event) 10497 { 10498 int err; 10499 unsigned long ref_ctr_offset; 10500 bool is_retprobe; 10501 10502 if (event->attr.type != perf_uprobe.type) 10503 return -ENOENT; 10504 10505 if (!perfmon_capable()) 10506 return -EACCES; 10507 10508 /* 10509 * no branch sampling for probe events 10510 */ 10511 if (has_branch_stack(event)) 10512 return -EOPNOTSUPP; 10513 10514 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE; 10515 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT; 10516 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe); 10517 if (err) 10518 return err; 10519 10520 event->destroy = perf_uprobe_destroy; 10521 10522 return 0; 10523 } 10524 #endif /* CONFIG_UPROBE_EVENTS */ 10525 10526 static inline void perf_tp_register(void) 10527 { 10528 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT); 10529 #ifdef CONFIG_KPROBE_EVENTS 10530 perf_pmu_register(&perf_kprobe, "kprobe", -1); 10531 #endif 10532 #ifdef CONFIG_UPROBE_EVENTS 10533 perf_pmu_register(&perf_uprobe, "uprobe", -1); 10534 #endif 10535 } 10536 10537 static void perf_event_free_filter(struct perf_event *event) 10538 { 10539 ftrace_profile_free_filter(event); 10540 } 10541 10542 /* 10543 * returns true if the event is a tracepoint, or a kprobe/upprobe created 10544 * with perf_event_open() 10545 */ 10546 static inline bool perf_event_is_tracing(struct perf_event *event) 10547 { 10548 if (event->pmu == &perf_tracepoint) 10549 return true; 10550 #ifdef CONFIG_KPROBE_EVENTS 10551 if (event->pmu == &perf_kprobe) 10552 return true; 10553 #endif 10554 #ifdef CONFIG_UPROBE_EVENTS 10555 if (event->pmu == &perf_uprobe) 10556 return true; 10557 #endif 10558 return false; 10559 } 10560 10561 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog, 10562 u64 bpf_cookie) 10563 { 10564 bool is_kprobe, is_uprobe, is_tracepoint, is_syscall_tp; 10565 10566 if (!perf_event_is_tracing(event)) 10567 return perf_event_set_bpf_handler(event, prog, bpf_cookie); 10568 10569 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_KPROBE; 10570 is_uprobe = event->tp_event->flags & TRACE_EVENT_FL_UPROBE; 10571 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT; 10572 is_syscall_tp = is_syscall_trace_event(event->tp_event); 10573 if (!is_kprobe && !is_uprobe && !is_tracepoint && !is_syscall_tp) 10574 /* bpf programs can only be attached to u/kprobe or tracepoint */ 10575 return -EINVAL; 10576 10577 if (((is_kprobe || is_uprobe) && prog->type != BPF_PROG_TYPE_KPROBE) || 10578 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) || 10579 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) 10580 return -EINVAL; 10581 10582 if (prog->type == BPF_PROG_TYPE_KPROBE && prog->sleepable && !is_uprobe) 10583 /* only uprobe programs are allowed to be sleepable */ 10584 return -EINVAL; 10585 10586 /* Kprobe override only works for kprobes, not uprobes. */ 10587 if (prog->kprobe_override && !is_kprobe) 10588 return -EINVAL; 10589 10590 if (is_tracepoint || is_syscall_tp) { 10591 int off = trace_event_get_offsets(event->tp_event); 10592 10593 if (prog->aux->max_ctx_offset > off) 10594 return -EACCES; 10595 } 10596 10597 return perf_event_attach_bpf_prog(event, prog, bpf_cookie); 10598 } 10599 10600 void perf_event_free_bpf_prog(struct perf_event *event) 10601 { 10602 if (!perf_event_is_tracing(event)) { 10603 perf_event_free_bpf_handler(event); 10604 return; 10605 } 10606 perf_event_detach_bpf_prog(event); 10607 } 10608 10609 #else 10610 10611 static inline void perf_tp_register(void) 10612 { 10613 } 10614 10615 static void perf_event_free_filter(struct perf_event *event) 10616 { 10617 } 10618 10619 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog, 10620 u64 bpf_cookie) 10621 { 10622 return -ENOENT; 10623 } 10624 10625 void perf_event_free_bpf_prog(struct perf_event *event) 10626 { 10627 } 10628 #endif /* CONFIG_EVENT_TRACING */ 10629 10630 #ifdef CONFIG_HAVE_HW_BREAKPOINT 10631 void perf_bp_event(struct perf_event *bp, void *data) 10632 { 10633 struct perf_sample_data sample; 10634 struct pt_regs *regs = data; 10635 10636 perf_sample_data_init(&sample, bp->attr.bp_addr, 0); 10637 10638 if (!bp->hw.state && !perf_exclude_event(bp, regs)) 10639 perf_swevent_event(bp, 1, &sample, regs); 10640 } 10641 #endif 10642 10643 /* 10644 * Allocate a new address filter 10645 */ 10646 static struct perf_addr_filter * 10647 perf_addr_filter_new(struct perf_event *event, struct list_head *filters) 10648 { 10649 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu); 10650 struct perf_addr_filter *filter; 10651 10652 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node); 10653 if (!filter) 10654 return NULL; 10655 10656 INIT_LIST_HEAD(&filter->entry); 10657 list_add_tail(&filter->entry, filters); 10658 10659 return filter; 10660 } 10661 10662 static void free_filters_list(struct list_head *filters) 10663 { 10664 struct perf_addr_filter *filter, *iter; 10665 10666 list_for_each_entry_safe(filter, iter, filters, entry) { 10667 path_put(&filter->path); 10668 list_del(&filter->entry); 10669 kfree(filter); 10670 } 10671 } 10672 10673 /* 10674 * Free existing address filters and optionally install new ones 10675 */ 10676 static void perf_addr_filters_splice(struct perf_event *event, 10677 struct list_head *head) 10678 { 10679 unsigned long flags; 10680 LIST_HEAD(list); 10681 10682 if (!has_addr_filter(event)) 10683 return; 10684 10685 /* don't bother with children, they don't have their own filters */ 10686 if (event->parent) 10687 return; 10688 10689 raw_spin_lock_irqsave(&event->addr_filters.lock, flags); 10690 10691 list_splice_init(&event->addr_filters.list, &list); 10692 if (head) 10693 list_splice(head, &event->addr_filters.list); 10694 10695 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags); 10696 10697 free_filters_list(&list); 10698 } 10699 10700 /* 10701 * Scan through mm's vmas and see if one of them matches the 10702 * @filter; if so, adjust filter's address range. 10703 * Called with mm::mmap_lock down for reading. 10704 */ 10705 static void perf_addr_filter_apply(struct perf_addr_filter *filter, 10706 struct mm_struct *mm, 10707 struct perf_addr_filter_range *fr) 10708 { 10709 struct vm_area_struct *vma; 10710 VMA_ITERATOR(vmi, mm, 0); 10711 10712 for_each_vma(vmi, vma) { 10713 if (!vma->vm_file) 10714 continue; 10715 10716 if (perf_addr_filter_vma_adjust(filter, vma, fr)) 10717 return; 10718 } 10719 } 10720 10721 /* 10722 * Update event's address range filters based on the 10723 * task's existing mappings, if any. 10724 */ 10725 static void perf_event_addr_filters_apply(struct perf_event *event) 10726 { 10727 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 10728 struct task_struct *task = READ_ONCE(event->ctx->task); 10729 struct perf_addr_filter *filter; 10730 struct mm_struct *mm = NULL; 10731 unsigned int count = 0; 10732 unsigned long flags; 10733 10734 /* 10735 * We may observe TASK_TOMBSTONE, which means that the event tear-down 10736 * will stop on the parent's child_mutex that our caller is also holding 10737 */ 10738 if (task == TASK_TOMBSTONE) 10739 return; 10740 10741 if (ifh->nr_file_filters) { 10742 mm = get_task_mm(task); 10743 if (!mm) 10744 goto restart; 10745 10746 mmap_read_lock(mm); 10747 } 10748 10749 raw_spin_lock_irqsave(&ifh->lock, flags); 10750 list_for_each_entry(filter, &ifh->list, entry) { 10751 if (filter->path.dentry) { 10752 /* 10753 * Adjust base offset if the filter is associated to a 10754 * binary that needs to be mapped: 10755 */ 10756 event->addr_filter_ranges[count].start = 0; 10757 event->addr_filter_ranges[count].size = 0; 10758 10759 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]); 10760 } else { 10761 event->addr_filter_ranges[count].start = filter->offset; 10762 event->addr_filter_ranges[count].size = filter->size; 10763 } 10764 10765 count++; 10766 } 10767 10768 event->addr_filters_gen++; 10769 raw_spin_unlock_irqrestore(&ifh->lock, flags); 10770 10771 if (ifh->nr_file_filters) { 10772 mmap_read_unlock(mm); 10773 10774 mmput(mm); 10775 } 10776 10777 restart: 10778 perf_event_stop(event, 1); 10779 } 10780 10781 /* 10782 * Address range filtering: limiting the data to certain 10783 * instruction address ranges. Filters are ioctl()ed to us from 10784 * userspace as ascii strings. 10785 * 10786 * Filter string format: 10787 * 10788 * ACTION RANGE_SPEC 10789 * where ACTION is one of the 10790 * * "filter": limit the trace to this region 10791 * * "start": start tracing from this address 10792 * * "stop": stop tracing at this address/region; 10793 * RANGE_SPEC is 10794 * * for kernel addresses: <start address>[/<size>] 10795 * * for object files: <start address>[/<size>]@</path/to/object/file> 10796 * 10797 * if <size> is not specified or is zero, the range is treated as a single 10798 * address; not valid for ACTION=="filter". 10799 */ 10800 enum { 10801 IF_ACT_NONE = -1, 10802 IF_ACT_FILTER, 10803 IF_ACT_START, 10804 IF_ACT_STOP, 10805 IF_SRC_FILE, 10806 IF_SRC_KERNEL, 10807 IF_SRC_FILEADDR, 10808 IF_SRC_KERNELADDR, 10809 }; 10810 10811 enum { 10812 IF_STATE_ACTION = 0, 10813 IF_STATE_SOURCE, 10814 IF_STATE_END, 10815 }; 10816 10817 static const match_table_t if_tokens = { 10818 { IF_ACT_FILTER, "filter" }, 10819 { IF_ACT_START, "start" }, 10820 { IF_ACT_STOP, "stop" }, 10821 { IF_SRC_FILE, "%u/%u@%s" }, 10822 { IF_SRC_KERNEL, "%u/%u" }, 10823 { IF_SRC_FILEADDR, "%u@%s" }, 10824 { IF_SRC_KERNELADDR, "%u" }, 10825 { IF_ACT_NONE, NULL }, 10826 }; 10827 10828 /* 10829 * Address filter string parser 10830 */ 10831 static int 10832 perf_event_parse_addr_filter(struct perf_event *event, char *fstr, 10833 struct list_head *filters) 10834 { 10835 struct perf_addr_filter *filter = NULL; 10836 char *start, *orig, *filename = NULL; 10837 substring_t args[MAX_OPT_ARGS]; 10838 int state = IF_STATE_ACTION, token; 10839 unsigned int kernel = 0; 10840 int ret = -EINVAL; 10841 10842 orig = fstr = kstrdup(fstr, GFP_KERNEL); 10843 if (!fstr) 10844 return -ENOMEM; 10845 10846 while ((start = strsep(&fstr, " ,\n")) != NULL) { 10847 static const enum perf_addr_filter_action_t actions[] = { 10848 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER, 10849 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START, 10850 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP, 10851 }; 10852 ret = -EINVAL; 10853 10854 if (!*start) 10855 continue; 10856 10857 /* filter definition begins */ 10858 if (state == IF_STATE_ACTION) { 10859 filter = perf_addr_filter_new(event, filters); 10860 if (!filter) 10861 goto fail; 10862 } 10863 10864 token = match_token(start, if_tokens, args); 10865 switch (token) { 10866 case IF_ACT_FILTER: 10867 case IF_ACT_START: 10868 case IF_ACT_STOP: 10869 if (state != IF_STATE_ACTION) 10870 goto fail; 10871 10872 filter->action = actions[token]; 10873 state = IF_STATE_SOURCE; 10874 break; 10875 10876 case IF_SRC_KERNELADDR: 10877 case IF_SRC_KERNEL: 10878 kernel = 1; 10879 fallthrough; 10880 10881 case IF_SRC_FILEADDR: 10882 case IF_SRC_FILE: 10883 if (state != IF_STATE_SOURCE) 10884 goto fail; 10885 10886 *args[0].to = 0; 10887 ret = kstrtoul(args[0].from, 0, &filter->offset); 10888 if (ret) 10889 goto fail; 10890 10891 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) { 10892 *args[1].to = 0; 10893 ret = kstrtoul(args[1].from, 0, &filter->size); 10894 if (ret) 10895 goto fail; 10896 } 10897 10898 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) { 10899 int fpos = token == IF_SRC_FILE ? 2 : 1; 10900 10901 kfree(filename); 10902 filename = match_strdup(&args[fpos]); 10903 if (!filename) { 10904 ret = -ENOMEM; 10905 goto fail; 10906 } 10907 } 10908 10909 state = IF_STATE_END; 10910 break; 10911 10912 default: 10913 goto fail; 10914 } 10915 10916 /* 10917 * Filter definition is fully parsed, validate and install it. 10918 * Make sure that it doesn't contradict itself or the event's 10919 * attribute. 10920 */ 10921 if (state == IF_STATE_END) { 10922 ret = -EINVAL; 10923 10924 /* 10925 * ACTION "filter" must have a non-zero length region 10926 * specified. 10927 */ 10928 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER && 10929 !filter->size) 10930 goto fail; 10931 10932 if (!kernel) { 10933 if (!filename) 10934 goto fail; 10935 10936 /* 10937 * For now, we only support file-based filters 10938 * in per-task events; doing so for CPU-wide 10939 * events requires additional context switching 10940 * trickery, since same object code will be 10941 * mapped at different virtual addresses in 10942 * different processes. 10943 */ 10944 ret = -EOPNOTSUPP; 10945 if (!event->ctx->task) 10946 goto fail; 10947 10948 /* look up the path and grab its inode */ 10949 ret = kern_path(filename, LOOKUP_FOLLOW, 10950 &filter->path); 10951 if (ret) 10952 goto fail; 10953 10954 ret = -EINVAL; 10955 if (!filter->path.dentry || 10956 !S_ISREG(d_inode(filter->path.dentry) 10957 ->i_mode)) 10958 goto fail; 10959 10960 event->addr_filters.nr_file_filters++; 10961 } 10962 10963 /* ready to consume more filters */ 10964 kfree(filename); 10965 filename = NULL; 10966 state = IF_STATE_ACTION; 10967 filter = NULL; 10968 kernel = 0; 10969 } 10970 } 10971 10972 if (state != IF_STATE_ACTION) 10973 goto fail; 10974 10975 kfree(filename); 10976 kfree(orig); 10977 10978 return 0; 10979 10980 fail: 10981 kfree(filename); 10982 free_filters_list(filters); 10983 kfree(orig); 10984 10985 return ret; 10986 } 10987 10988 static int 10989 perf_event_set_addr_filter(struct perf_event *event, char *filter_str) 10990 { 10991 LIST_HEAD(filters); 10992 int ret; 10993 10994 /* 10995 * Since this is called in perf_ioctl() path, we're already holding 10996 * ctx::mutex. 10997 */ 10998 lockdep_assert_held(&event->ctx->mutex); 10999 11000 if (WARN_ON_ONCE(event->parent)) 11001 return -EINVAL; 11002 11003 ret = perf_event_parse_addr_filter(event, filter_str, &filters); 11004 if (ret) 11005 goto fail_clear_files; 11006 11007 ret = event->pmu->addr_filters_validate(&filters); 11008 if (ret) 11009 goto fail_free_filters; 11010 11011 /* remove existing filters, if any */ 11012 perf_addr_filters_splice(event, &filters); 11013 11014 /* install new filters */ 11015 perf_event_for_each_child(event, perf_event_addr_filters_apply); 11016 11017 return ret; 11018 11019 fail_free_filters: 11020 free_filters_list(&filters); 11021 11022 fail_clear_files: 11023 event->addr_filters.nr_file_filters = 0; 11024 11025 return ret; 11026 } 11027 11028 static int perf_event_set_filter(struct perf_event *event, void __user *arg) 11029 { 11030 int ret = -EINVAL; 11031 char *filter_str; 11032 11033 filter_str = strndup_user(arg, PAGE_SIZE); 11034 if (IS_ERR(filter_str)) 11035 return PTR_ERR(filter_str); 11036 11037 #ifdef CONFIG_EVENT_TRACING 11038 if (perf_event_is_tracing(event)) { 11039 struct perf_event_context *ctx = event->ctx; 11040 11041 /* 11042 * Beware, here be dragons!! 11043 * 11044 * the tracepoint muck will deadlock against ctx->mutex, but 11045 * the tracepoint stuff does not actually need it. So 11046 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we 11047 * already have a reference on ctx. 11048 * 11049 * This can result in event getting moved to a different ctx, 11050 * but that does not affect the tracepoint state. 11051 */ 11052 mutex_unlock(&ctx->mutex); 11053 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str); 11054 mutex_lock(&ctx->mutex); 11055 } else 11056 #endif 11057 if (has_addr_filter(event)) 11058 ret = perf_event_set_addr_filter(event, filter_str); 11059 11060 kfree(filter_str); 11061 return ret; 11062 } 11063 11064 /* 11065 * hrtimer based swevent callback 11066 */ 11067 11068 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer) 11069 { 11070 enum hrtimer_restart ret = HRTIMER_RESTART; 11071 struct perf_sample_data data; 11072 struct pt_regs *regs; 11073 struct perf_event *event; 11074 u64 period; 11075 11076 event = container_of(hrtimer, struct perf_event, hw.hrtimer); 11077 11078 if (event->state != PERF_EVENT_STATE_ACTIVE) 11079 return HRTIMER_NORESTART; 11080 11081 event->pmu->read(event); 11082 11083 perf_sample_data_init(&data, 0, event->hw.last_period); 11084 regs = get_irq_regs(); 11085 11086 if (regs && !perf_exclude_event(event, regs)) { 11087 if (!(event->attr.exclude_idle && is_idle_task(current))) 11088 if (__perf_event_overflow(event, 1, &data, regs)) 11089 ret = HRTIMER_NORESTART; 11090 } 11091 11092 period = max_t(u64, 10000, event->hw.sample_period); 11093 hrtimer_forward_now(hrtimer, ns_to_ktime(period)); 11094 11095 return ret; 11096 } 11097 11098 static void perf_swevent_start_hrtimer(struct perf_event *event) 11099 { 11100 struct hw_perf_event *hwc = &event->hw; 11101 s64 period; 11102 11103 if (!is_sampling_event(event)) 11104 return; 11105 11106 period = local64_read(&hwc->period_left); 11107 if (period) { 11108 if (period < 0) 11109 period = 10000; 11110 11111 local64_set(&hwc->period_left, 0); 11112 } else { 11113 period = max_t(u64, 10000, hwc->sample_period); 11114 } 11115 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period), 11116 HRTIMER_MODE_REL_PINNED_HARD); 11117 } 11118 11119 static void perf_swevent_cancel_hrtimer(struct perf_event *event) 11120 { 11121 struct hw_perf_event *hwc = &event->hw; 11122 11123 if (is_sampling_event(event)) { 11124 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer); 11125 local64_set(&hwc->period_left, ktime_to_ns(remaining)); 11126 11127 hrtimer_cancel(&hwc->hrtimer); 11128 } 11129 } 11130 11131 static void perf_swevent_init_hrtimer(struct perf_event *event) 11132 { 11133 struct hw_perf_event *hwc = &event->hw; 11134 11135 if (!is_sampling_event(event)) 11136 return; 11137 11138 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); 11139 hwc->hrtimer.function = perf_swevent_hrtimer; 11140 11141 /* 11142 * Since hrtimers have a fixed rate, we can do a static freq->period 11143 * mapping and avoid the whole period adjust feedback stuff. 11144 */ 11145 if (event->attr.freq) { 11146 long freq = event->attr.sample_freq; 11147 11148 event->attr.sample_period = NSEC_PER_SEC / freq; 11149 hwc->sample_period = event->attr.sample_period; 11150 local64_set(&hwc->period_left, hwc->sample_period); 11151 hwc->last_period = hwc->sample_period; 11152 event->attr.freq = 0; 11153 } 11154 } 11155 11156 /* 11157 * Software event: cpu wall time clock 11158 */ 11159 11160 static void cpu_clock_event_update(struct perf_event *event) 11161 { 11162 s64 prev; 11163 u64 now; 11164 11165 now = local_clock(); 11166 prev = local64_xchg(&event->hw.prev_count, now); 11167 local64_add(now - prev, &event->count); 11168 } 11169 11170 static void cpu_clock_event_start(struct perf_event *event, int flags) 11171 { 11172 local64_set(&event->hw.prev_count, local_clock()); 11173 perf_swevent_start_hrtimer(event); 11174 } 11175 11176 static void cpu_clock_event_stop(struct perf_event *event, int flags) 11177 { 11178 perf_swevent_cancel_hrtimer(event); 11179 cpu_clock_event_update(event); 11180 } 11181 11182 static int cpu_clock_event_add(struct perf_event *event, int flags) 11183 { 11184 if (flags & PERF_EF_START) 11185 cpu_clock_event_start(event, flags); 11186 perf_event_update_userpage(event); 11187 11188 return 0; 11189 } 11190 11191 static void cpu_clock_event_del(struct perf_event *event, int flags) 11192 { 11193 cpu_clock_event_stop(event, flags); 11194 } 11195 11196 static void cpu_clock_event_read(struct perf_event *event) 11197 { 11198 cpu_clock_event_update(event); 11199 } 11200 11201 static int cpu_clock_event_init(struct perf_event *event) 11202 { 11203 if (event->attr.type != perf_cpu_clock.type) 11204 return -ENOENT; 11205 11206 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK) 11207 return -ENOENT; 11208 11209 /* 11210 * no branch sampling for software events 11211 */ 11212 if (has_branch_stack(event)) 11213 return -EOPNOTSUPP; 11214 11215 perf_swevent_init_hrtimer(event); 11216 11217 return 0; 11218 } 11219 11220 static struct pmu perf_cpu_clock = { 11221 .task_ctx_nr = perf_sw_context, 11222 11223 .capabilities = PERF_PMU_CAP_NO_NMI, 11224 .dev = PMU_NULL_DEV, 11225 11226 .event_init = cpu_clock_event_init, 11227 .add = cpu_clock_event_add, 11228 .del = cpu_clock_event_del, 11229 .start = cpu_clock_event_start, 11230 .stop = cpu_clock_event_stop, 11231 .read = cpu_clock_event_read, 11232 }; 11233 11234 /* 11235 * Software event: task time clock 11236 */ 11237 11238 static void task_clock_event_update(struct perf_event *event, u64 now) 11239 { 11240 u64 prev; 11241 s64 delta; 11242 11243 prev = local64_xchg(&event->hw.prev_count, now); 11244 delta = now - prev; 11245 local64_add(delta, &event->count); 11246 } 11247 11248 static void task_clock_event_start(struct perf_event *event, int flags) 11249 { 11250 local64_set(&event->hw.prev_count, event->ctx->time); 11251 perf_swevent_start_hrtimer(event); 11252 } 11253 11254 static void task_clock_event_stop(struct perf_event *event, int flags) 11255 { 11256 perf_swevent_cancel_hrtimer(event); 11257 task_clock_event_update(event, event->ctx->time); 11258 } 11259 11260 static int task_clock_event_add(struct perf_event *event, int flags) 11261 { 11262 if (flags & PERF_EF_START) 11263 task_clock_event_start(event, flags); 11264 perf_event_update_userpage(event); 11265 11266 return 0; 11267 } 11268 11269 static void task_clock_event_del(struct perf_event *event, int flags) 11270 { 11271 task_clock_event_stop(event, PERF_EF_UPDATE); 11272 } 11273 11274 static void task_clock_event_read(struct perf_event *event) 11275 { 11276 u64 now = perf_clock(); 11277 u64 delta = now - event->ctx->timestamp; 11278 u64 time = event->ctx->time + delta; 11279 11280 task_clock_event_update(event, time); 11281 } 11282 11283 static int task_clock_event_init(struct perf_event *event) 11284 { 11285 if (event->attr.type != perf_task_clock.type) 11286 return -ENOENT; 11287 11288 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK) 11289 return -ENOENT; 11290 11291 /* 11292 * no branch sampling for software events 11293 */ 11294 if (has_branch_stack(event)) 11295 return -EOPNOTSUPP; 11296 11297 perf_swevent_init_hrtimer(event); 11298 11299 return 0; 11300 } 11301 11302 static struct pmu perf_task_clock = { 11303 .task_ctx_nr = perf_sw_context, 11304 11305 .capabilities = PERF_PMU_CAP_NO_NMI, 11306 .dev = PMU_NULL_DEV, 11307 11308 .event_init = task_clock_event_init, 11309 .add = task_clock_event_add, 11310 .del = task_clock_event_del, 11311 .start = task_clock_event_start, 11312 .stop = task_clock_event_stop, 11313 .read = task_clock_event_read, 11314 }; 11315 11316 static void perf_pmu_nop_void(struct pmu *pmu) 11317 { 11318 } 11319 11320 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags) 11321 { 11322 } 11323 11324 static int perf_pmu_nop_int(struct pmu *pmu) 11325 { 11326 return 0; 11327 } 11328 11329 static int perf_event_nop_int(struct perf_event *event, u64 value) 11330 { 11331 return 0; 11332 } 11333 11334 static DEFINE_PER_CPU(unsigned int, nop_txn_flags); 11335 11336 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags) 11337 { 11338 __this_cpu_write(nop_txn_flags, flags); 11339 11340 if (flags & ~PERF_PMU_TXN_ADD) 11341 return; 11342 11343 perf_pmu_disable(pmu); 11344 } 11345 11346 static int perf_pmu_commit_txn(struct pmu *pmu) 11347 { 11348 unsigned int flags = __this_cpu_read(nop_txn_flags); 11349 11350 __this_cpu_write(nop_txn_flags, 0); 11351 11352 if (flags & ~PERF_PMU_TXN_ADD) 11353 return 0; 11354 11355 perf_pmu_enable(pmu); 11356 return 0; 11357 } 11358 11359 static void perf_pmu_cancel_txn(struct pmu *pmu) 11360 { 11361 unsigned int flags = __this_cpu_read(nop_txn_flags); 11362 11363 __this_cpu_write(nop_txn_flags, 0); 11364 11365 if (flags & ~PERF_PMU_TXN_ADD) 11366 return; 11367 11368 perf_pmu_enable(pmu); 11369 } 11370 11371 static int perf_event_idx_default(struct perf_event *event) 11372 { 11373 return 0; 11374 } 11375 11376 static void free_pmu_context(struct pmu *pmu) 11377 { 11378 free_percpu(pmu->cpu_pmu_context); 11379 } 11380 11381 /* 11382 * Let userspace know that this PMU supports address range filtering: 11383 */ 11384 static ssize_t nr_addr_filters_show(struct device *dev, 11385 struct device_attribute *attr, 11386 char *page) 11387 { 11388 struct pmu *pmu = dev_get_drvdata(dev); 11389 11390 return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters); 11391 } 11392 DEVICE_ATTR_RO(nr_addr_filters); 11393 11394 static struct idr pmu_idr; 11395 11396 static ssize_t 11397 type_show(struct device *dev, struct device_attribute *attr, char *page) 11398 { 11399 struct pmu *pmu = dev_get_drvdata(dev); 11400 11401 return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->type); 11402 } 11403 static DEVICE_ATTR_RO(type); 11404 11405 static ssize_t 11406 perf_event_mux_interval_ms_show(struct device *dev, 11407 struct device_attribute *attr, 11408 char *page) 11409 { 11410 struct pmu *pmu = dev_get_drvdata(dev); 11411 11412 return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->hrtimer_interval_ms); 11413 } 11414 11415 static DEFINE_MUTEX(mux_interval_mutex); 11416 11417 static ssize_t 11418 perf_event_mux_interval_ms_store(struct device *dev, 11419 struct device_attribute *attr, 11420 const char *buf, size_t count) 11421 { 11422 struct pmu *pmu = dev_get_drvdata(dev); 11423 int timer, cpu, ret; 11424 11425 ret = kstrtoint(buf, 0, &timer); 11426 if (ret) 11427 return ret; 11428 11429 if (timer < 1) 11430 return -EINVAL; 11431 11432 /* same value, noting to do */ 11433 if (timer == pmu->hrtimer_interval_ms) 11434 return count; 11435 11436 mutex_lock(&mux_interval_mutex); 11437 pmu->hrtimer_interval_ms = timer; 11438 11439 /* update all cpuctx for this PMU */ 11440 cpus_read_lock(); 11441 for_each_online_cpu(cpu) { 11442 struct perf_cpu_pmu_context *cpc; 11443 cpc = per_cpu_ptr(pmu->cpu_pmu_context, cpu); 11444 cpc->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer); 11445 11446 cpu_function_call(cpu, perf_mux_hrtimer_restart_ipi, cpc); 11447 } 11448 cpus_read_unlock(); 11449 mutex_unlock(&mux_interval_mutex); 11450 11451 return count; 11452 } 11453 static DEVICE_ATTR_RW(perf_event_mux_interval_ms); 11454 11455 static struct attribute *pmu_dev_attrs[] = { 11456 &dev_attr_type.attr, 11457 &dev_attr_perf_event_mux_interval_ms.attr, 11458 &dev_attr_nr_addr_filters.attr, 11459 NULL, 11460 }; 11461 11462 static umode_t pmu_dev_is_visible(struct kobject *kobj, struct attribute *a, int n) 11463 { 11464 struct device *dev = kobj_to_dev(kobj); 11465 struct pmu *pmu = dev_get_drvdata(dev); 11466 11467 if (n == 2 && !pmu->nr_addr_filters) 11468 return 0; 11469 11470 return a->mode; 11471 } 11472 11473 static struct attribute_group pmu_dev_attr_group = { 11474 .is_visible = pmu_dev_is_visible, 11475 .attrs = pmu_dev_attrs, 11476 }; 11477 11478 static const struct attribute_group *pmu_dev_groups[] = { 11479 &pmu_dev_attr_group, 11480 NULL, 11481 }; 11482 11483 static int pmu_bus_running; 11484 static struct bus_type pmu_bus = { 11485 .name = "event_source", 11486 .dev_groups = pmu_dev_groups, 11487 }; 11488 11489 static void pmu_dev_release(struct device *dev) 11490 { 11491 kfree(dev); 11492 } 11493 11494 static int pmu_dev_alloc(struct pmu *pmu) 11495 { 11496 int ret = -ENOMEM; 11497 11498 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL); 11499 if (!pmu->dev) 11500 goto out; 11501 11502 pmu->dev->groups = pmu->attr_groups; 11503 device_initialize(pmu->dev); 11504 11505 dev_set_drvdata(pmu->dev, pmu); 11506 pmu->dev->bus = &pmu_bus; 11507 pmu->dev->parent = pmu->parent; 11508 pmu->dev->release = pmu_dev_release; 11509 11510 ret = dev_set_name(pmu->dev, "%s", pmu->name); 11511 if (ret) 11512 goto free_dev; 11513 11514 ret = device_add(pmu->dev); 11515 if (ret) 11516 goto free_dev; 11517 11518 if (pmu->attr_update) { 11519 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update); 11520 if (ret) 11521 goto del_dev; 11522 } 11523 11524 out: 11525 return ret; 11526 11527 del_dev: 11528 device_del(pmu->dev); 11529 11530 free_dev: 11531 put_device(pmu->dev); 11532 goto out; 11533 } 11534 11535 static struct lock_class_key cpuctx_mutex; 11536 static struct lock_class_key cpuctx_lock; 11537 11538 int perf_pmu_register(struct pmu *pmu, const char *name, int type) 11539 { 11540 int cpu, ret, max = PERF_TYPE_MAX; 11541 11542 mutex_lock(&pmus_lock); 11543 ret = -ENOMEM; 11544 pmu->pmu_disable_count = alloc_percpu(int); 11545 if (!pmu->pmu_disable_count) 11546 goto unlock; 11547 11548 pmu->type = -1; 11549 if (WARN_ONCE(!name, "Can not register anonymous pmu.\n")) { 11550 ret = -EINVAL; 11551 goto free_pdc; 11552 } 11553 11554 pmu->name = name; 11555 11556 if (type >= 0) 11557 max = type; 11558 11559 ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL); 11560 if (ret < 0) 11561 goto free_pdc; 11562 11563 WARN_ON(type >= 0 && ret != type); 11564 11565 type = ret; 11566 pmu->type = type; 11567 11568 if (pmu_bus_running && !pmu->dev) { 11569 ret = pmu_dev_alloc(pmu); 11570 if (ret) 11571 goto free_idr; 11572 } 11573 11574 ret = -ENOMEM; 11575 pmu->cpu_pmu_context = alloc_percpu(struct perf_cpu_pmu_context); 11576 if (!pmu->cpu_pmu_context) 11577 goto free_dev; 11578 11579 for_each_possible_cpu(cpu) { 11580 struct perf_cpu_pmu_context *cpc; 11581 11582 cpc = per_cpu_ptr(pmu->cpu_pmu_context, cpu); 11583 __perf_init_event_pmu_context(&cpc->epc, pmu); 11584 __perf_mux_hrtimer_init(cpc, cpu); 11585 } 11586 11587 if (!pmu->start_txn) { 11588 if (pmu->pmu_enable) { 11589 /* 11590 * If we have pmu_enable/pmu_disable calls, install 11591 * transaction stubs that use that to try and batch 11592 * hardware accesses. 11593 */ 11594 pmu->start_txn = perf_pmu_start_txn; 11595 pmu->commit_txn = perf_pmu_commit_txn; 11596 pmu->cancel_txn = perf_pmu_cancel_txn; 11597 } else { 11598 pmu->start_txn = perf_pmu_nop_txn; 11599 pmu->commit_txn = perf_pmu_nop_int; 11600 pmu->cancel_txn = perf_pmu_nop_void; 11601 } 11602 } 11603 11604 if (!pmu->pmu_enable) { 11605 pmu->pmu_enable = perf_pmu_nop_void; 11606 pmu->pmu_disable = perf_pmu_nop_void; 11607 } 11608 11609 if (!pmu->check_period) 11610 pmu->check_period = perf_event_nop_int; 11611 11612 if (!pmu->event_idx) 11613 pmu->event_idx = perf_event_idx_default; 11614 11615 list_add_rcu(&pmu->entry, &pmus); 11616 atomic_set(&pmu->exclusive_cnt, 0); 11617 ret = 0; 11618 unlock: 11619 mutex_unlock(&pmus_lock); 11620 11621 return ret; 11622 11623 free_dev: 11624 if (pmu->dev && pmu->dev != PMU_NULL_DEV) { 11625 device_del(pmu->dev); 11626 put_device(pmu->dev); 11627 } 11628 11629 free_idr: 11630 idr_remove(&pmu_idr, pmu->type); 11631 11632 free_pdc: 11633 free_percpu(pmu->pmu_disable_count); 11634 goto unlock; 11635 } 11636 EXPORT_SYMBOL_GPL(perf_pmu_register); 11637 11638 void perf_pmu_unregister(struct pmu *pmu) 11639 { 11640 mutex_lock(&pmus_lock); 11641 list_del_rcu(&pmu->entry); 11642 11643 /* 11644 * We dereference the pmu list under both SRCU and regular RCU, so 11645 * synchronize against both of those. 11646 */ 11647 synchronize_srcu(&pmus_srcu); 11648 synchronize_rcu(); 11649 11650 free_percpu(pmu->pmu_disable_count); 11651 idr_remove(&pmu_idr, pmu->type); 11652 if (pmu_bus_running && pmu->dev && pmu->dev != PMU_NULL_DEV) { 11653 if (pmu->nr_addr_filters) 11654 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters); 11655 device_del(pmu->dev); 11656 put_device(pmu->dev); 11657 } 11658 free_pmu_context(pmu); 11659 mutex_unlock(&pmus_lock); 11660 } 11661 EXPORT_SYMBOL_GPL(perf_pmu_unregister); 11662 11663 static inline bool has_extended_regs(struct perf_event *event) 11664 { 11665 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) || 11666 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK); 11667 } 11668 11669 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event) 11670 { 11671 struct perf_event_context *ctx = NULL; 11672 int ret; 11673 11674 if (!try_module_get(pmu->module)) 11675 return -ENODEV; 11676 11677 /* 11678 * A number of pmu->event_init() methods iterate the sibling_list to, 11679 * for example, validate if the group fits on the PMU. Therefore, 11680 * if this is a sibling event, acquire the ctx->mutex to protect 11681 * the sibling_list. 11682 */ 11683 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) { 11684 /* 11685 * This ctx->mutex can nest when we're called through 11686 * inheritance. See the perf_event_ctx_lock_nested() comment. 11687 */ 11688 ctx = perf_event_ctx_lock_nested(event->group_leader, 11689 SINGLE_DEPTH_NESTING); 11690 BUG_ON(!ctx); 11691 } 11692 11693 event->pmu = pmu; 11694 ret = pmu->event_init(event); 11695 11696 if (ctx) 11697 perf_event_ctx_unlock(event->group_leader, ctx); 11698 11699 if (!ret) { 11700 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) && 11701 has_extended_regs(event)) 11702 ret = -EOPNOTSUPP; 11703 11704 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE && 11705 event_has_any_exclude_flag(event)) 11706 ret = -EINVAL; 11707 11708 if (ret && event->destroy) 11709 event->destroy(event); 11710 } 11711 11712 if (ret) 11713 module_put(pmu->module); 11714 11715 return ret; 11716 } 11717 11718 static struct pmu *perf_init_event(struct perf_event *event) 11719 { 11720 bool extended_type = false; 11721 int idx, type, ret; 11722 struct pmu *pmu; 11723 11724 idx = srcu_read_lock(&pmus_srcu); 11725 11726 /* 11727 * Save original type before calling pmu->event_init() since certain 11728 * pmus overwrites event->attr.type to forward event to another pmu. 11729 */ 11730 event->orig_type = event->attr.type; 11731 11732 /* Try parent's PMU first: */ 11733 if (event->parent && event->parent->pmu) { 11734 pmu = event->parent->pmu; 11735 ret = perf_try_init_event(pmu, event); 11736 if (!ret) 11737 goto unlock; 11738 } 11739 11740 /* 11741 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE 11742 * are often aliases for PERF_TYPE_RAW. 11743 */ 11744 type = event->attr.type; 11745 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) { 11746 type = event->attr.config >> PERF_PMU_TYPE_SHIFT; 11747 if (!type) { 11748 type = PERF_TYPE_RAW; 11749 } else { 11750 extended_type = true; 11751 event->attr.config &= PERF_HW_EVENT_MASK; 11752 } 11753 } 11754 11755 again: 11756 rcu_read_lock(); 11757 pmu = idr_find(&pmu_idr, type); 11758 rcu_read_unlock(); 11759 if (pmu) { 11760 if (event->attr.type != type && type != PERF_TYPE_RAW && 11761 !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE)) 11762 goto fail; 11763 11764 ret = perf_try_init_event(pmu, event); 11765 if (ret == -ENOENT && event->attr.type != type && !extended_type) { 11766 type = event->attr.type; 11767 goto again; 11768 } 11769 11770 if (ret) 11771 pmu = ERR_PTR(ret); 11772 11773 goto unlock; 11774 } 11775 11776 list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) { 11777 ret = perf_try_init_event(pmu, event); 11778 if (!ret) 11779 goto unlock; 11780 11781 if (ret != -ENOENT) { 11782 pmu = ERR_PTR(ret); 11783 goto unlock; 11784 } 11785 } 11786 fail: 11787 pmu = ERR_PTR(-ENOENT); 11788 unlock: 11789 srcu_read_unlock(&pmus_srcu, idx); 11790 11791 return pmu; 11792 } 11793 11794 static void attach_sb_event(struct perf_event *event) 11795 { 11796 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu); 11797 11798 raw_spin_lock(&pel->lock); 11799 list_add_rcu(&event->sb_list, &pel->list); 11800 raw_spin_unlock(&pel->lock); 11801 } 11802 11803 /* 11804 * We keep a list of all !task (and therefore per-cpu) events 11805 * that need to receive side-band records. 11806 * 11807 * This avoids having to scan all the various PMU per-cpu contexts 11808 * looking for them. 11809 */ 11810 static void account_pmu_sb_event(struct perf_event *event) 11811 { 11812 if (is_sb_event(event)) 11813 attach_sb_event(event); 11814 } 11815 11816 /* Freq events need the tick to stay alive (see perf_event_task_tick). */ 11817 static void account_freq_event_nohz(void) 11818 { 11819 #ifdef CONFIG_NO_HZ_FULL 11820 /* Lock so we don't race with concurrent unaccount */ 11821 spin_lock(&nr_freq_lock); 11822 if (atomic_inc_return(&nr_freq_events) == 1) 11823 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS); 11824 spin_unlock(&nr_freq_lock); 11825 #endif 11826 } 11827 11828 static void account_freq_event(void) 11829 { 11830 if (tick_nohz_full_enabled()) 11831 account_freq_event_nohz(); 11832 else 11833 atomic_inc(&nr_freq_events); 11834 } 11835 11836 11837 static void account_event(struct perf_event *event) 11838 { 11839 bool inc = false; 11840 11841 if (event->parent) 11842 return; 11843 11844 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB)) 11845 inc = true; 11846 if (event->attr.mmap || event->attr.mmap_data) 11847 atomic_inc(&nr_mmap_events); 11848 if (event->attr.build_id) 11849 atomic_inc(&nr_build_id_events); 11850 if (event->attr.comm) 11851 atomic_inc(&nr_comm_events); 11852 if (event->attr.namespaces) 11853 atomic_inc(&nr_namespaces_events); 11854 if (event->attr.cgroup) 11855 atomic_inc(&nr_cgroup_events); 11856 if (event->attr.task) 11857 atomic_inc(&nr_task_events); 11858 if (event->attr.freq) 11859 account_freq_event(); 11860 if (event->attr.context_switch) { 11861 atomic_inc(&nr_switch_events); 11862 inc = true; 11863 } 11864 if (has_branch_stack(event)) 11865 inc = true; 11866 if (is_cgroup_event(event)) 11867 inc = true; 11868 if (event->attr.ksymbol) 11869 atomic_inc(&nr_ksymbol_events); 11870 if (event->attr.bpf_event) 11871 atomic_inc(&nr_bpf_events); 11872 if (event->attr.text_poke) 11873 atomic_inc(&nr_text_poke_events); 11874 11875 if (inc) { 11876 /* 11877 * We need the mutex here because static_branch_enable() 11878 * must complete *before* the perf_sched_count increment 11879 * becomes visible. 11880 */ 11881 if (atomic_inc_not_zero(&perf_sched_count)) 11882 goto enabled; 11883 11884 mutex_lock(&perf_sched_mutex); 11885 if (!atomic_read(&perf_sched_count)) { 11886 static_branch_enable(&perf_sched_events); 11887 /* 11888 * Guarantee that all CPUs observe they key change and 11889 * call the perf scheduling hooks before proceeding to 11890 * install events that need them. 11891 */ 11892 synchronize_rcu(); 11893 } 11894 /* 11895 * Now that we have waited for the sync_sched(), allow further 11896 * increments to by-pass the mutex. 11897 */ 11898 atomic_inc(&perf_sched_count); 11899 mutex_unlock(&perf_sched_mutex); 11900 } 11901 enabled: 11902 11903 account_pmu_sb_event(event); 11904 } 11905 11906 /* 11907 * Allocate and initialize an event structure 11908 */ 11909 static struct perf_event * 11910 perf_event_alloc(struct perf_event_attr *attr, int cpu, 11911 struct task_struct *task, 11912 struct perf_event *group_leader, 11913 struct perf_event *parent_event, 11914 perf_overflow_handler_t overflow_handler, 11915 void *context, int cgroup_fd) 11916 { 11917 struct pmu *pmu; 11918 struct perf_event *event; 11919 struct hw_perf_event *hwc; 11920 long err = -EINVAL; 11921 int node; 11922 11923 if ((unsigned)cpu >= nr_cpu_ids) { 11924 if (!task || cpu != -1) 11925 return ERR_PTR(-EINVAL); 11926 } 11927 if (attr->sigtrap && !task) { 11928 /* Requires a task: avoid signalling random tasks. */ 11929 return ERR_PTR(-EINVAL); 11930 } 11931 11932 node = (cpu >= 0) ? cpu_to_node(cpu) : -1; 11933 event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO, 11934 node); 11935 if (!event) 11936 return ERR_PTR(-ENOMEM); 11937 11938 /* 11939 * Single events are their own group leaders, with an 11940 * empty sibling list: 11941 */ 11942 if (!group_leader) 11943 group_leader = event; 11944 11945 mutex_init(&event->child_mutex); 11946 INIT_LIST_HEAD(&event->child_list); 11947 11948 INIT_LIST_HEAD(&event->event_entry); 11949 INIT_LIST_HEAD(&event->sibling_list); 11950 INIT_LIST_HEAD(&event->active_list); 11951 init_event_group(event); 11952 INIT_LIST_HEAD(&event->rb_entry); 11953 INIT_LIST_HEAD(&event->active_entry); 11954 INIT_LIST_HEAD(&event->addr_filters.list); 11955 INIT_HLIST_NODE(&event->hlist_entry); 11956 11957 11958 init_waitqueue_head(&event->waitq); 11959 init_irq_work(&event->pending_irq, perf_pending_irq); 11960 init_task_work(&event->pending_task, perf_pending_task); 11961 11962 mutex_init(&event->mmap_mutex); 11963 raw_spin_lock_init(&event->addr_filters.lock); 11964 11965 atomic_long_set(&event->refcount, 1); 11966 event->cpu = cpu; 11967 event->attr = *attr; 11968 event->group_leader = group_leader; 11969 event->pmu = NULL; 11970 event->oncpu = -1; 11971 11972 event->parent = parent_event; 11973 11974 event->ns = get_pid_ns(task_active_pid_ns(current)); 11975 event->id = atomic64_inc_return(&perf_event_id); 11976 11977 event->state = PERF_EVENT_STATE_INACTIVE; 11978 11979 if (parent_event) 11980 event->event_caps = parent_event->event_caps; 11981 11982 if (task) { 11983 event->attach_state = PERF_ATTACH_TASK; 11984 /* 11985 * XXX pmu::event_init needs to know what task to account to 11986 * and we cannot use the ctx information because we need the 11987 * pmu before we get a ctx. 11988 */ 11989 event->hw.target = get_task_struct(task); 11990 } 11991 11992 event->clock = &local_clock; 11993 if (parent_event) 11994 event->clock = parent_event->clock; 11995 11996 if (!overflow_handler && parent_event) { 11997 overflow_handler = parent_event->overflow_handler; 11998 context = parent_event->overflow_handler_context; 11999 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING) 12000 if (overflow_handler == bpf_overflow_handler) { 12001 struct bpf_prog *prog = parent_event->prog; 12002 12003 bpf_prog_inc(prog); 12004 event->prog = prog; 12005 event->orig_overflow_handler = 12006 parent_event->orig_overflow_handler; 12007 } 12008 #endif 12009 } 12010 12011 if (overflow_handler) { 12012 event->overflow_handler = overflow_handler; 12013 event->overflow_handler_context = context; 12014 } else if (is_write_backward(event)){ 12015 event->overflow_handler = perf_event_output_backward; 12016 event->overflow_handler_context = NULL; 12017 } else { 12018 event->overflow_handler = perf_event_output_forward; 12019 event->overflow_handler_context = NULL; 12020 } 12021 12022 perf_event__state_init(event); 12023 12024 pmu = NULL; 12025 12026 hwc = &event->hw; 12027 hwc->sample_period = attr->sample_period; 12028 if (attr->freq && attr->sample_freq) 12029 hwc->sample_period = 1; 12030 hwc->last_period = hwc->sample_period; 12031 12032 local64_set(&hwc->period_left, hwc->sample_period); 12033 12034 /* 12035 * We currently do not support PERF_SAMPLE_READ on inherited events. 12036 * See perf_output_read(). 12037 */ 12038 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ)) 12039 goto err_ns; 12040 12041 if (!has_branch_stack(event)) 12042 event->attr.branch_sample_type = 0; 12043 12044 pmu = perf_init_event(event); 12045 if (IS_ERR(pmu)) { 12046 err = PTR_ERR(pmu); 12047 goto err_ns; 12048 } 12049 12050 /* 12051 * Disallow uncore-task events. Similarly, disallow uncore-cgroup 12052 * events (they don't make sense as the cgroup will be different 12053 * on other CPUs in the uncore mask). 12054 */ 12055 if (pmu->task_ctx_nr == perf_invalid_context && (task || cgroup_fd != -1)) { 12056 err = -EINVAL; 12057 goto err_pmu; 12058 } 12059 12060 if (event->attr.aux_output && 12061 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) { 12062 err = -EOPNOTSUPP; 12063 goto err_pmu; 12064 } 12065 12066 if (cgroup_fd != -1) { 12067 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader); 12068 if (err) 12069 goto err_pmu; 12070 } 12071 12072 err = exclusive_event_init(event); 12073 if (err) 12074 goto err_pmu; 12075 12076 if (has_addr_filter(event)) { 12077 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters, 12078 sizeof(struct perf_addr_filter_range), 12079 GFP_KERNEL); 12080 if (!event->addr_filter_ranges) { 12081 err = -ENOMEM; 12082 goto err_per_task; 12083 } 12084 12085 /* 12086 * Clone the parent's vma offsets: they are valid until exec() 12087 * even if the mm is not shared with the parent. 12088 */ 12089 if (event->parent) { 12090 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 12091 12092 raw_spin_lock_irq(&ifh->lock); 12093 memcpy(event->addr_filter_ranges, 12094 event->parent->addr_filter_ranges, 12095 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range)); 12096 raw_spin_unlock_irq(&ifh->lock); 12097 } 12098 12099 /* force hw sync on the address filters */ 12100 event->addr_filters_gen = 1; 12101 } 12102 12103 if (!event->parent) { 12104 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) { 12105 err = get_callchain_buffers(attr->sample_max_stack); 12106 if (err) 12107 goto err_addr_filters; 12108 } 12109 } 12110 12111 err = security_perf_event_alloc(event); 12112 if (err) 12113 goto err_callchain_buffer; 12114 12115 /* symmetric to unaccount_event() in _free_event() */ 12116 account_event(event); 12117 12118 return event; 12119 12120 err_callchain_buffer: 12121 if (!event->parent) { 12122 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) 12123 put_callchain_buffers(); 12124 } 12125 err_addr_filters: 12126 kfree(event->addr_filter_ranges); 12127 12128 err_per_task: 12129 exclusive_event_destroy(event); 12130 12131 err_pmu: 12132 if (is_cgroup_event(event)) 12133 perf_detach_cgroup(event); 12134 if (event->destroy) 12135 event->destroy(event); 12136 module_put(pmu->module); 12137 err_ns: 12138 if (event->hw.target) 12139 put_task_struct(event->hw.target); 12140 call_rcu(&event->rcu_head, free_event_rcu); 12141 12142 return ERR_PTR(err); 12143 } 12144 12145 static int perf_copy_attr(struct perf_event_attr __user *uattr, 12146 struct perf_event_attr *attr) 12147 { 12148 u32 size; 12149 int ret; 12150 12151 /* Zero the full structure, so that a short copy will be nice. */ 12152 memset(attr, 0, sizeof(*attr)); 12153 12154 ret = get_user(size, &uattr->size); 12155 if (ret) 12156 return ret; 12157 12158 /* ABI compatibility quirk: */ 12159 if (!size) 12160 size = PERF_ATTR_SIZE_VER0; 12161 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE) 12162 goto err_size; 12163 12164 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size); 12165 if (ret) { 12166 if (ret == -E2BIG) 12167 goto err_size; 12168 return ret; 12169 } 12170 12171 attr->size = size; 12172 12173 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3) 12174 return -EINVAL; 12175 12176 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1)) 12177 return -EINVAL; 12178 12179 if (attr->read_format & ~(PERF_FORMAT_MAX-1)) 12180 return -EINVAL; 12181 12182 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) { 12183 u64 mask = attr->branch_sample_type; 12184 12185 /* only using defined bits */ 12186 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1)) 12187 return -EINVAL; 12188 12189 /* at least one branch bit must be set */ 12190 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL)) 12191 return -EINVAL; 12192 12193 /* propagate priv level, when not set for branch */ 12194 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) { 12195 12196 /* exclude_kernel checked on syscall entry */ 12197 if (!attr->exclude_kernel) 12198 mask |= PERF_SAMPLE_BRANCH_KERNEL; 12199 12200 if (!attr->exclude_user) 12201 mask |= PERF_SAMPLE_BRANCH_USER; 12202 12203 if (!attr->exclude_hv) 12204 mask |= PERF_SAMPLE_BRANCH_HV; 12205 /* 12206 * adjust user setting (for HW filter setup) 12207 */ 12208 attr->branch_sample_type = mask; 12209 } 12210 /* privileged levels capture (kernel, hv): check permissions */ 12211 if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) { 12212 ret = perf_allow_kernel(attr); 12213 if (ret) 12214 return ret; 12215 } 12216 } 12217 12218 if (attr->sample_type & PERF_SAMPLE_REGS_USER) { 12219 ret = perf_reg_validate(attr->sample_regs_user); 12220 if (ret) 12221 return ret; 12222 } 12223 12224 if (attr->sample_type & PERF_SAMPLE_STACK_USER) { 12225 if (!arch_perf_have_user_stack_dump()) 12226 return -ENOSYS; 12227 12228 /* 12229 * We have __u32 type for the size, but so far 12230 * we can only use __u16 as maximum due to the 12231 * __u16 sample size limit. 12232 */ 12233 if (attr->sample_stack_user >= USHRT_MAX) 12234 return -EINVAL; 12235 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64))) 12236 return -EINVAL; 12237 } 12238 12239 if (!attr->sample_max_stack) 12240 attr->sample_max_stack = sysctl_perf_event_max_stack; 12241 12242 if (attr->sample_type & PERF_SAMPLE_REGS_INTR) 12243 ret = perf_reg_validate(attr->sample_regs_intr); 12244 12245 #ifndef CONFIG_CGROUP_PERF 12246 if (attr->sample_type & PERF_SAMPLE_CGROUP) 12247 return -EINVAL; 12248 #endif 12249 if ((attr->sample_type & PERF_SAMPLE_WEIGHT) && 12250 (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT)) 12251 return -EINVAL; 12252 12253 if (!attr->inherit && attr->inherit_thread) 12254 return -EINVAL; 12255 12256 if (attr->remove_on_exec && attr->enable_on_exec) 12257 return -EINVAL; 12258 12259 if (attr->sigtrap && !attr->remove_on_exec) 12260 return -EINVAL; 12261 12262 out: 12263 return ret; 12264 12265 err_size: 12266 put_user(sizeof(*attr), &uattr->size); 12267 ret = -E2BIG; 12268 goto out; 12269 } 12270 12271 static void mutex_lock_double(struct mutex *a, struct mutex *b) 12272 { 12273 if (b < a) 12274 swap(a, b); 12275 12276 mutex_lock(a); 12277 mutex_lock_nested(b, SINGLE_DEPTH_NESTING); 12278 } 12279 12280 static int 12281 perf_event_set_output(struct perf_event *event, struct perf_event *output_event) 12282 { 12283 struct perf_buffer *rb = NULL; 12284 int ret = -EINVAL; 12285 12286 if (!output_event) { 12287 mutex_lock(&event->mmap_mutex); 12288 goto set; 12289 } 12290 12291 /* don't allow circular references */ 12292 if (event == output_event) 12293 goto out; 12294 12295 /* 12296 * Don't allow cross-cpu buffers 12297 */ 12298 if (output_event->cpu != event->cpu) 12299 goto out; 12300 12301 /* 12302 * If its not a per-cpu rb, it must be the same task. 12303 */ 12304 if (output_event->cpu == -1 && output_event->hw.target != event->hw.target) 12305 goto out; 12306 12307 /* 12308 * Mixing clocks in the same buffer is trouble you don't need. 12309 */ 12310 if (output_event->clock != event->clock) 12311 goto out; 12312 12313 /* 12314 * Either writing ring buffer from beginning or from end. 12315 * Mixing is not allowed. 12316 */ 12317 if (is_write_backward(output_event) != is_write_backward(event)) 12318 goto out; 12319 12320 /* 12321 * If both events generate aux data, they must be on the same PMU 12322 */ 12323 if (has_aux(event) && has_aux(output_event) && 12324 event->pmu != output_event->pmu) 12325 goto out; 12326 12327 /* 12328 * Hold both mmap_mutex to serialize against perf_mmap_close(). Since 12329 * output_event is already on rb->event_list, and the list iteration 12330 * restarts after every removal, it is guaranteed this new event is 12331 * observed *OR* if output_event is already removed, it's guaranteed we 12332 * observe !rb->mmap_count. 12333 */ 12334 mutex_lock_double(&event->mmap_mutex, &output_event->mmap_mutex); 12335 set: 12336 /* Can't redirect output if we've got an active mmap() */ 12337 if (atomic_read(&event->mmap_count)) 12338 goto unlock; 12339 12340 if (output_event) { 12341 /* get the rb we want to redirect to */ 12342 rb = ring_buffer_get(output_event); 12343 if (!rb) 12344 goto unlock; 12345 12346 /* did we race against perf_mmap_close() */ 12347 if (!atomic_read(&rb->mmap_count)) { 12348 ring_buffer_put(rb); 12349 goto unlock; 12350 } 12351 } 12352 12353 ring_buffer_attach(event, rb); 12354 12355 ret = 0; 12356 unlock: 12357 mutex_unlock(&event->mmap_mutex); 12358 if (output_event) 12359 mutex_unlock(&output_event->mmap_mutex); 12360 12361 out: 12362 return ret; 12363 } 12364 12365 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id) 12366 { 12367 bool nmi_safe = false; 12368 12369 switch (clk_id) { 12370 case CLOCK_MONOTONIC: 12371 event->clock = &ktime_get_mono_fast_ns; 12372 nmi_safe = true; 12373 break; 12374 12375 case CLOCK_MONOTONIC_RAW: 12376 event->clock = &ktime_get_raw_fast_ns; 12377 nmi_safe = true; 12378 break; 12379 12380 case CLOCK_REALTIME: 12381 event->clock = &ktime_get_real_ns; 12382 break; 12383 12384 case CLOCK_BOOTTIME: 12385 event->clock = &ktime_get_boottime_ns; 12386 break; 12387 12388 case CLOCK_TAI: 12389 event->clock = &ktime_get_clocktai_ns; 12390 break; 12391 12392 default: 12393 return -EINVAL; 12394 } 12395 12396 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI)) 12397 return -EINVAL; 12398 12399 return 0; 12400 } 12401 12402 static bool 12403 perf_check_permission(struct perf_event_attr *attr, struct task_struct *task) 12404 { 12405 unsigned int ptrace_mode = PTRACE_MODE_READ_REALCREDS; 12406 bool is_capable = perfmon_capable(); 12407 12408 if (attr->sigtrap) { 12409 /* 12410 * perf_event_attr::sigtrap sends signals to the other task. 12411 * Require the current task to also have CAP_KILL. 12412 */ 12413 rcu_read_lock(); 12414 is_capable &= ns_capable(__task_cred(task)->user_ns, CAP_KILL); 12415 rcu_read_unlock(); 12416 12417 /* 12418 * If the required capabilities aren't available, checks for 12419 * ptrace permissions: upgrade to ATTACH, since sending signals 12420 * can effectively change the target task. 12421 */ 12422 ptrace_mode = PTRACE_MODE_ATTACH_REALCREDS; 12423 } 12424 12425 /* 12426 * Preserve ptrace permission check for backwards compatibility. The 12427 * ptrace check also includes checks that the current task and other 12428 * task have matching uids, and is therefore not done here explicitly. 12429 */ 12430 return is_capable || ptrace_may_access(task, ptrace_mode); 12431 } 12432 12433 /** 12434 * sys_perf_event_open - open a performance event, associate it to a task/cpu 12435 * 12436 * @attr_uptr: event_id type attributes for monitoring/sampling 12437 * @pid: target pid 12438 * @cpu: target cpu 12439 * @group_fd: group leader event fd 12440 * @flags: perf event open flags 12441 */ 12442 SYSCALL_DEFINE5(perf_event_open, 12443 struct perf_event_attr __user *, attr_uptr, 12444 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags) 12445 { 12446 struct perf_event *group_leader = NULL, *output_event = NULL; 12447 struct perf_event_pmu_context *pmu_ctx; 12448 struct perf_event *event, *sibling; 12449 struct perf_event_attr attr; 12450 struct perf_event_context *ctx; 12451 struct file *event_file = NULL; 12452 struct fd group = {NULL, 0}; 12453 struct task_struct *task = NULL; 12454 struct pmu *pmu; 12455 int event_fd; 12456 int move_group = 0; 12457 int err; 12458 int f_flags = O_RDWR; 12459 int cgroup_fd = -1; 12460 12461 /* for future expandability... */ 12462 if (flags & ~PERF_FLAG_ALL) 12463 return -EINVAL; 12464 12465 err = perf_copy_attr(attr_uptr, &attr); 12466 if (err) 12467 return err; 12468 12469 /* Do we allow access to perf_event_open(2) ? */ 12470 err = security_perf_event_open(&attr, PERF_SECURITY_OPEN); 12471 if (err) 12472 return err; 12473 12474 if (!attr.exclude_kernel) { 12475 err = perf_allow_kernel(&attr); 12476 if (err) 12477 return err; 12478 } 12479 12480 if (attr.namespaces) { 12481 if (!perfmon_capable()) 12482 return -EACCES; 12483 } 12484 12485 if (attr.freq) { 12486 if (attr.sample_freq > sysctl_perf_event_sample_rate) 12487 return -EINVAL; 12488 } else { 12489 if (attr.sample_period & (1ULL << 63)) 12490 return -EINVAL; 12491 } 12492 12493 /* Only privileged users can get physical addresses */ 12494 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) { 12495 err = perf_allow_kernel(&attr); 12496 if (err) 12497 return err; 12498 } 12499 12500 /* REGS_INTR can leak data, lockdown must prevent this */ 12501 if (attr.sample_type & PERF_SAMPLE_REGS_INTR) { 12502 err = security_locked_down(LOCKDOWN_PERF); 12503 if (err) 12504 return err; 12505 } 12506 12507 /* 12508 * In cgroup mode, the pid argument is used to pass the fd 12509 * opened to the cgroup directory in cgroupfs. The cpu argument 12510 * designates the cpu on which to monitor threads from that 12511 * cgroup. 12512 */ 12513 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1)) 12514 return -EINVAL; 12515 12516 if (flags & PERF_FLAG_FD_CLOEXEC) 12517 f_flags |= O_CLOEXEC; 12518 12519 event_fd = get_unused_fd_flags(f_flags); 12520 if (event_fd < 0) 12521 return event_fd; 12522 12523 if (group_fd != -1) { 12524 err = perf_fget_light(group_fd, &group); 12525 if (err) 12526 goto err_fd; 12527 group_leader = group.file->private_data; 12528 if (flags & PERF_FLAG_FD_OUTPUT) 12529 output_event = group_leader; 12530 if (flags & PERF_FLAG_FD_NO_GROUP) 12531 group_leader = NULL; 12532 } 12533 12534 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) { 12535 task = find_lively_task_by_vpid(pid); 12536 if (IS_ERR(task)) { 12537 err = PTR_ERR(task); 12538 goto err_group_fd; 12539 } 12540 } 12541 12542 if (task && group_leader && 12543 group_leader->attr.inherit != attr.inherit) { 12544 err = -EINVAL; 12545 goto err_task; 12546 } 12547 12548 if (flags & PERF_FLAG_PID_CGROUP) 12549 cgroup_fd = pid; 12550 12551 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, 12552 NULL, NULL, cgroup_fd); 12553 if (IS_ERR(event)) { 12554 err = PTR_ERR(event); 12555 goto err_task; 12556 } 12557 12558 if (is_sampling_event(event)) { 12559 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) { 12560 err = -EOPNOTSUPP; 12561 goto err_alloc; 12562 } 12563 } 12564 12565 /* 12566 * Special case software events and allow them to be part of 12567 * any hardware group. 12568 */ 12569 pmu = event->pmu; 12570 12571 if (attr.use_clockid) { 12572 err = perf_event_set_clock(event, attr.clockid); 12573 if (err) 12574 goto err_alloc; 12575 } 12576 12577 if (pmu->task_ctx_nr == perf_sw_context) 12578 event->event_caps |= PERF_EV_CAP_SOFTWARE; 12579 12580 if (task) { 12581 err = down_read_interruptible(&task->signal->exec_update_lock); 12582 if (err) 12583 goto err_alloc; 12584 12585 /* 12586 * We must hold exec_update_lock across this and any potential 12587 * perf_install_in_context() call for this new event to 12588 * serialize against exec() altering our credentials (and the 12589 * perf_event_exit_task() that could imply). 12590 */ 12591 err = -EACCES; 12592 if (!perf_check_permission(&attr, task)) 12593 goto err_cred; 12594 } 12595 12596 /* 12597 * Get the target context (task or percpu): 12598 */ 12599 ctx = find_get_context(task, event); 12600 if (IS_ERR(ctx)) { 12601 err = PTR_ERR(ctx); 12602 goto err_cred; 12603 } 12604 12605 mutex_lock(&ctx->mutex); 12606 12607 if (ctx->task == TASK_TOMBSTONE) { 12608 err = -ESRCH; 12609 goto err_locked; 12610 } 12611 12612 if (!task) { 12613 /* 12614 * Check if the @cpu we're creating an event for is online. 12615 * 12616 * We use the perf_cpu_context::ctx::mutex to serialize against 12617 * the hotplug notifiers. See perf_event_{init,exit}_cpu(). 12618 */ 12619 struct perf_cpu_context *cpuctx = per_cpu_ptr(&perf_cpu_context, event->cpu); 12620 12621 if (!cpuctx->online) { 12622 err = -ENODEV; 12623 goto err_locked; 12624 } 12625 } 12626 12627 if (group_leader) { 12628 err = -EINVAL; 12629 12630 /* 12631 * Do not allow a recursive hierarchy (this new sibling 12632 * becoming part of another group-sibling): 12633 */ 12634 if (group_leader->group_leader != group_leader) 12635 goto err_locked; 12636 12637 /* All events in a group should have the same clock */ 12638 if (group_leader->clock != event->clock) 12639 goto err_locked; 12640 12641 /* 12642 * Make sure we're both events for the same CPU; 12643 * grouping events for different CPUs is broken; since 12644 * you can never concurrently schedule them anyhow. 12645 */ 12646 if (group_leader->cpu != event->cpu) 12647 goto err_locked; 12648 12649 /* 12650 * Make sure we're both on the same context; either task or cpu. 12651 */ 12652 if (group_leader->ctx != ctx) 12653 goto err_locked; 12654 12655 /* 12656 * Only a group leader can be exclusive or pinned 12657 */ 12658 if (attr.exclusive || attr.pinned) 12659 goto err_locked; 12660 12661 if (is_software_event(event) && 12662 !in_software_context(group_leader)) { 12663 /* 12664 * If the event is a sw event, but the group_leader 12665 * is on hw context. 12666 * 12667 * Allow the addition of software events to hw 12668 * groups, this is safe because software events 12669 * never fail to schedule. 12670 * 12671 * Note the comment that goes with struct 12672 * perf_event_pmu_context. 12673 */ 12674 pmu = group_leader->pmu_ctx->pmu; 12675 } else if (!is_software_event(event)) { 12676 if (is_software_event(group_leader) && 12677 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) { 12678 /* 12679 * In case the group is a pure software group, and we 12680 * try to add a hardware event, move the whole group to 12681 * the hardware context. 12682 */ 12683 move_group = 1; 12684 } 12685 12686 /* Don't allow group of multiple hw events from different pmus */ 12687 if (!in_software_context(group_leader) && 12688 group_leader->pmu_ctx->pmu != pmu) 12689 goto err_locked; 12690 } 12691 } 12692 12693 /* 12694 * Now that we're certain of the pmu; find the pmu_ctx. 12695 */ 12696 pmu_ctx = find_get_pmu_context(pmu, ctx, event); 12697 if (IS_ERR(pmu_ctx)) { 12698 err = PTR_ERR(pmu_ctx); 12699 goto err_locked; 12700 } 12701 event->pmu_ctx = pmu_ctx; 12702 12703 if (output_event) { 12704 err = perf_event_set_output(event, output_event); 12705 if (err) 12706 goto err_context; 12707 } 12708 12709 if (!perf_event_validate_size(event)) { 12710 err = -E2BIG; 12711 goto err_context; 12712 } 12713 12714 if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) { 12715 err = -EINVAL; 12716 goto err_context; 12717 } 12718 12719 /* 12720 * Must be under the same ctx::mutex as perf_install_in_context(), 12721 * because we need to serialize with concurrent event creation. 12722 */ 12723 if (!exclusive_event_installable(event, ctx)) { 12724 err = -EBUSY; 12725 goto err_context; 12726 } 12727 12728 WARN_ON_ONCE(ctx->parent_ctx); 12729 12730 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, f_flags); 12731 if (IS_ERR(event_file)) { 12732 err = PTR_ERR(event_file); 12733 event_file = NULL; 12734 goto err_context; 12735 } 12736 12737 /* 12738 * This is the point on no return; we cannot fail hereafter. This is 12739 * where we start modifying current state. 12740 */ 12741 12742 if (move_group) { 12743 perf_remove_from_context(group_leader, 0); 12744 put_pmu_ctx(group_leader->pmu_ctx); 12745 12746 for_each_sibling_event(sibling, group_leader) { 12747 perf_remove_from_context(sibling, 0); 12748 put_pmu_ctx(sibling->pmu_ctx); 12749 } 12750 12751 /* 12752 * Install the group siblings before the group leader. 12753 * 12754 * Because a group leader will try and install the entire group 12755 * (through the sibling list, which is still in-tact), we can 12756 * end up with siblings installed in the wrong context. 12757 * 12758 * By installing siblings first we NO-OP because they're not 12759 * reachable through the group lists. 12760 */ 12761 for_each_sibling_event(sibling, group_leader) { 12762 sibling->pmu_ctx = pmu_ctx; 12763 get_pmu_ctx(pmu_ctx); 12764 perf_event__state_init(sibling); 12765 perf_install_in_context(ctx, sibling, sibling->cpu); 12766 } 12767 12768 /* 12769 * Removing from the context ends up with disabled 12770 * event. What we want here is event in the initial 12771 * startup state, ready to be add into new context. 12772 */ 12773 group_leader->pmu_ctx = pmu_ctx; 12774 get_pmu_ctx(pmu_ctx); 12775 perf_event__state_init(group_leader); 12776 perf_install_in_context(ctx, group_leader, group_leader->cpu); 12777 } 12778 12779 /* 12780 * Precalculate sample_data sizes; do while holding ctx::mutex such 12781 * that we're serialized against further additions and before 12782 * perf_install_in_context() which is the point the event is active and 12783 * can use these values. 12784 */ 12785 perf_event__header_size(event); 12786 perf_event__id_header_size(event); 12787 12788 event->owner = current; 12789 12790 perf_install_in_context(ctx, event, event->cpu); 12791 perf_unpin_context(ctx); 12792 12793 mutex_unlock(&ctx->mutex); 12794 12795 if (task) { 12796 up_read(&task->signal->exec_update_lock); 12797 put_task_struct(task); 12798 } 12799 12800 mutex_lock(¤t->perf_event_mutex); 12801 list_add_tail(&event->owner_entry, ¤t->perf_event_list); 12802 mutex_unlock(¤t->perf_event_mutex); 12803 12804 /* 12805 * Drop the reference on the group_event after placing the 12806 * new event on the sibling_list. This ensures destruction 12807 * of the group leader will find the pointer to itself in 12808 * perf_group_detach(). 12809 */ 12810 fdput(group); 12811 fd_install(event_fd, event_file); 12812 return event_fd; 12813 12814 err_context: 12815 put_pmu_ctx(event->pmu_ctx); 12816 event->pmu_ctx = NULL; /* _free_event() */ 12817 err_locked: 12818 mutex_unlock(&ctx->mutex); 12819 perf_unpin_context(ctx); 12820 put_ctx(ctx); 12821 err_cred: 12822 if (task) 12823 up_read(&task->signal->exec_update_lock); 12824 err_alloc: 12825 free_event(event); 12826 err_task: 12827 if (task) 12828 put_task_struct(task); 12829 err_group_fd: 12830 fdput(group); 12831 err_fd: 12832 put_unused_fd(event_fd); 12833 return err; 12834 } 12835 12836 /** 12837 * perf_event_create_kernel_counter 12838 * 12839 * @attr: attributes of the counter to create 12840 * @cpu: cpu in which the counter is bound 12841 * @task: task to profile (NULL for percpu) 12842 * @overflow_handler: callback to trigger when we hit the event 12843 * @context: context data could be used in overflow_handler callback 12844 */ 12845 struct perf_event * 12846 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, 12847 struct task_struct *task, 12848 perf_overflow_handler_t overflow_handler, 12849 void *context) 12850 { 12851 struct perf_event_pmu_context *pmu_ctx; 12852 struct perf_event_context *ctx; 12853 struct perf_event *event; 12854 struct pmu *pmu; 12855 int err; 12856 12857 /* 12858 * Grouping is not supported for kernel events, neither is 'AUX', 12859 * make sure the caller's intentions are adjusted. 12860 */ 12861 if (attr->aux_output) 12862 return ERR_PTR(-EINVAL); 12863 12864 event = perf_event_alloc(attr, cpu, task, NULL, NULL, 12865 overflow_handler, context, -1); 12866 if (IS_ERR(event)) { 12867 err = PTR_ERR(event); 12868 goto err; 12869 } 12870 12871 /* Mark owner so we could distinguish it from user events. */ 12872 event->owner = TASK_TOMBSTONE; 12873 pmu = event->pmu; 12874 12875 if (pmu->task_ctx_nr == perf_sw_context) 12876 event->event_caps |= PERF_EV_CAP_SOFTWARE; 12877 12878 /* 12879 * Get the target context (task or percpu): 12880 */ 12881 ctx = find_get_context(task, event); 12882 if (IS_ERR(ctx)) { 12883 err = PTR_ERR(ctx); 12884 goto err_alloc; 12885 } 12886 12887 WARN_ON_ONCE(ctx->parent_ctx); 12888 mutex_lock(&ctx->mutex); 12889 if (ctx->task == TASK_TOMBSTONE) { 12890 err = -ESRCH; 12891 goto err_unlock; 12892 } 12893 12894 pmu_ctx = find_get_pmu_context(pmu, ctx, event); 12895 if (IS_ERR(pmu_ctx)) { 12896 err = PTR_ERR(pmu_ctx); 12897 goto err_unlock; 12898 } 12899 event->pmu_ctx = pmu_ctx; 12900 12901 if (!task) { 12902 /* 12903 * Check if the @cpu we're creating an event for is online. 12904 * 12905 * We use the perf_cpu_context::ctx::mutex to serialize against 12906 * the hotplug notifiers. See perf_event_{init,exit}_cpu(). 12907 */ 12908 struct perf_cpu_context *cpuctx = 12909 container_of(ctx, struct perf_cpu_context, ctx); 12910 if (!cpuctx->online) { 12911 err = -ENODEV; 12912 goto err_pmu_ctx; 12913 } 12914 } 12915 12916 if (!exclusive_event_installable(event, ctx)) { 12917 err = -EBUSY; 12918 goto err_pmu_ctx; 12919 } 12920 12921 perf_install_in_context(ctx, event, event->cpu); 12922 perf_unpin_context(ctx); 12923 mutex_unlock(&ctx->mutex); 12924 12925 return event; 12926 12927 err_pmu_ctx: 12928 put_pmu_ctx(pmu_ctx); 12929 event->pmu_ctx = NULL; /* _free_event() */ 12930 err_unlock: 12931 mutex_unlock(&ctx->mutex); 12932 perf_unpin_context(ctx); 12933 put_ctx(ctx); 12934 err_alloc: 12935 free_event(event); 12936 err: 12937 return ERR_PTR(err); 12938 } 12939 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter); 12940 12941 static void __perf_pmu_remove(struct perf_event_context *ctx, 12942 int cpu, struct pmu *pmu, 12943 struct perf_event_groups *groups, 12944 struct list_head *events) 12945 { 12946 struct perf_event *event, *sibling; 12947 12948 perf_event_groups_for_cpu_pmu(event, groups, cpu, pmu) { 12949 perf_remove_from_context(event, 0); 12950 put_pmu_ctx(event->pmu_ctx); 12951 list_add(&event->migrate_entry, events); 12952 12953 for_each_sibling_event(sibling, event) { 12954 perf_remove_from_context(sibling, 0); 12955 put_pmu_ctx(sibling->pmu_ctx); 12956 list_add(&sibling->migrate_entry, events); 12957 } 12958 } 12959 } 12960 12961 static void __perf_pmu_install_event(struct pmu *pmu, 12962 struct perf_event_context *ctx, 12963 int cpu, struct perf_event *event) 12964 { 12965 struct perf_event_pmu_context *epc; 12966 struct perf_event_context *old_ctx = event->ctx; 12967 12968 get_ctx(ctx); /* normally find_get_context() */ 12969 12970 event->cpu = cpu; 12971 epc = find_get_pmu_context(pmu, ctx, event); 12972 event->pmu_ctx = epc; 12973 12974 if (event->state >= PERF_EVENT_STATE_OFF) 12975 event->state = PERF_EVENT_STATE_INACTIVE; 12976 perf_install_in_context(ctx, event, cpu); 12977 12978 /* 12979 * Now that event->ctx is updated and visible, put the old ctx. 12980 */ 12981 put_ctx(old_ctx); 12982 } 12983 12984 static void __perf_pmu_install(struct perf_event_context *ctx, 12985 int cpu, struct pmu *pmu, struct list_head *events) 12986 { 12987 struct perf_event *event, *tmp; 12988 12989 /* 12990 * Re-instate events in 2 passes. 12991 * 12992 * Skip over group leaders and only install siblings on this first 12993 * pass, siblings will not get enabled without a leader, however a 12994 * leader will enable its siblings, even if those are still on the old 12995 * context. 12996 */ 12997 list_for_each_entry_safe(event, tmp, events, migrate_entry) { 12998 if (event->group_leader == event) 12999 continue; 13000 13001 list_del(&event->migrate_entry); 13002 __perf_pmu_install_event(pmu, ctx, cpu, event); 13003 } 13004 13005 /* 13006 * Once all the siblings are setup properly, install the group leaders 13007 * to make it go. 13008 */ 13009 list_for_each_entry_safe(event, tmp, events, migrate_entry) { 13010 list_del(&event->migrate_entry); 13011 __perf_pmu_install_event(pmu, ctx, cpu, event); 13012 } 13013 } 13014 13015 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu) 13016 { 13017 struct perf_event_context *src_ctx, *dst_ctx; 13018 LIST_HEAD(events); 13019 13020 /* 13021 * Since per-cpu context is persistent, no need to grab an extra 13022 * reference. 13023 */ 13024 src_ctx = &per_cpu_ptr(&perf_cpu_context, src_cpu)->ctx; 13025 dst_ctx = &per_cpu_ptr(&perf_cpu_context, dst_cpu)->ctx; 13026 13027 /* 13028 * See perf_event_ctx_lock() for comments on the details 13029 * of swizzling perf_event::ctx. 13030 */ 13031 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex); 13032 13033 __perf_pmu_remove(src_ctx, src_cpu, pmu, &src_ctx->pinned_groups, &events); 13034 __perf_pmu_remove(src_ctx, src_cpu, pmu, &src_ctx->flexible_groups, &events); 13035 13036 if (!list_empty(&events)) { 13037 /* 13038 * Wait for the events to quiesce before re-instating them. 13039 */ 13040 synchronize_rcu(); 13041 13042 __perf_pmu_install(dst_ctx, dst_cpu, pmu, &events); 13043 } 13044 13045 mutex_unlock(&dst_ctx->mutex); 13046 mutex_unlock(&src_ctx->mutex); 13047 } 13048 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context); 13049 13050 static void sync_child_event(struct perf_event *child_event) 13051 { 13052 struct perf_event *parent_event = child_event->parent; 13053 u64 child_val; 13054 13055 if (child_event->attr.inherit_stat) { 13056 struct task_struct *task = child_event->ctx->task; 13057 13058 if (task && task != TASK_TOMBSTONE) 13059 perf_event_read_event(child_event, task); 13060 } 13061 13062 child_val = perf_event_count(child_event); 13063 13064 /* 13065 * Add back the child's count to the parent's count: 13066 */ 13067 atomic64_add(child_val, &parent_event->child_count); 13068 atomic64_add(child_event->total_time_enabled, 13069 &parent_event->child_total_time_enabled); 13070 atomic64_add(child_event->total_time_running, 13071 &parent_event->child_total_time_running); 13072 } 13073 13074 static void 13075 perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx) 13076 { 13077 struct perf_event *parent_event = event->parent; 13078 unsigned long detach_flags = 0; 13079 13080 if (parent_event) { 13081 /* 13082 * Do not destroy the 'original' grouping; because of the 13083 * context switch optimization the original events could've 13084 * ended up in a random child task. 13085 * 13086 * If we were to destroy the original group, all group related 13087 * operations would cease to function properly after this 13088 * random child dies. 13089 * 13090 * Do destroy all inherited groups, we don't care about those 13091 * and being thorough is better. 13092 */ 13093 detach_flags = DETACH_GROUP | DETACH_CHILD; 13094 mutex_lock(&parent_event->child_mutex); 13095 } 13096 13097 perf_remove_from_context(event, detach_flags); 13098 13099 raw_spin_lock_irq(&ctx->lock); 13100 if (event->state > PERF_EVENT_STATE_EXIT) 13101 perf_event_set_state(event, PERF_EVENT_STATE_EXIT); 13102 raw_spin_unlock_irq(&ctx->lock); 13103 13104 /* 13105 * Child events can be freed. 13106 */ 13107 if (parent_event) { 13108 mutex_unlock(&parent_event->child_mutex); 13109 /* 13110 * Kick perf_poll() for is_event_hup(); 13111 */ 13112 perf_event_wakeup(parent_event); 13113 free_event(event); 13114 put_event(parent_event); 13115 return; 13116 } 13117 13118 /* 13119 * Parent events are governed by their filedesc, retain them. 13120 */ 13121 perf_event_wakeup(event); 13122 } 13123 13124 static void perf_event_exit_task_context(struct task_struct *child) 13125 { 13126 struct perf_event_context *child_ctx, *clone_ctx = NULL; 13127 struct perf_event *child_event, *next; 13128 13129 WARN_ON_ONCE(child != current); 13130 13131 child_ctx = perf_pin_task_context(child); 13132 if (!child_ctx) 13133 return; 13134 13135 /* 13136 * In order to reduce the amount of tricky in ctx tear-down, we hold 13137 * ctx::mutex over the entire thing. This serializes against almost 13138 * everything that wants to access the ctx. 13139 * 13140 * The exception is sys_perf_event_open() / 13141 * perf_event_create_kernel_count() which does find_get_context() 13142 * without ctx::mutex (it cannot because of the move_group double mutex 13143 * lock thing). See the comments in perf_install_in_context(). 13144 */ 13145 mutex_lock(&child_ctx->mutex); 13146 13147 /* 13148 * In a single ctx::lock section, de-schedule the events and detach the 13149 * context from the task such that we cannot ever get it scheduled back 13150 * in. 13151 */ 13152 raw_spin_lock_irq(&child_ctx->lock); 13153 task_ctx_sched_out(child_ctx, EVENT_ALL); 13154 13155 /* 13156 * Now that the context is inactive, destroy the task <-> ctx relation 13157 * and mark the context dead. 13158 */ 13159 RCU_INIT_POINTER(child->perf_event_ctxp, NULL); 13160 put_ctx(child_ctx); /* cannot be last */ 13161 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE); 13162 put_task_struct(current); /* cannot be last */ 13163 13164 clone_ctx = unclone_ctx(child_ctx); 13165 raw_spin_unlock_irq(&child_ctx->lock); 13166 13167 if (clone_ctx) 13168 put_ctx(clone_ctx); 13169 13170 /* 13171 * Report the task dead after unscheduling the events so that we 13172 * won't get any samples after PERF_RECORD_EXIT. We can however still 13173 * get a few PERF_RECORD_READ events. 13174 */ 13175 perf_event_task(child, child_ctx, 0); 13176 13177 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry) 13178 perf_event_exit_event(child_event, child_ctx); 13179 13180 mutex_unlock(&child_ctx->mutex); 13181 13182 put_ctx(child_ctx); 13183 } 13184 13185 /* 13186 * When a child task exits, feed back event values to parent events. 13187 * 13188 * Can be called with exec_update_lock held when called from 13189 * setup_new_exec(). 13190 */ 13191 void perf_event_exit_task(struct task_struct *child) 13192 { 13193 struct perf_event *event, *tmp; 13194 13195 mutex_lock(&child->perf_event_mutex); 13196 list_for_each_entry_safe(event, tmp, &child->perf_event_list, 13197 owner_entry) { 13198 list_del_init(&event->owner_entry); 13199 13200 /* 13201 * Ensure the list deletion is visible before we clear 13202 * the owner, closes a race against perf_release() where 13203 * we need to serialize on the owner->perf_event_mutex. 13204 */ 13205 smp_store_release(&event->owner, NULL); 13206 } 13207 mutex_unlock(&child->perf_event_mutex); 13208 13209 perf_event_exit_task_context(child); 13210 13211 /* 13212 * The perf_event_exit_task_context calls perf_event_task 13213 * with child's task_ctx, which generates EXIT events for 13214 * child contexts and sets child->perf_event_ctxp[] to NULL. 13215 * At this point we need to send EXIT events to cpu contexts. 13216 */ 13217 perf_event_task(child, NULL, 0); 13218 } 13219 13220 static void perf_free_event(struct perf_event *event, 13221 struct perf_event_context *ctx) 13222 { 13223 struct perf_event *parent = event->parent; 13224 13225 if (WARN_ON_ONCE(!parent)) 13226 return; 13227 13228 mutex_lock(&parent->child_mutex); 13229 list_del_init(&event->child_list); 13230 mutex_unlock(&parent->child_mutex); 13231 13232 put_event(parent); 13233 13234 raw_spin_lock_irq(&ctx->lock); 13235 perf_group_detach(event); 13236 list_del_event(event, ctx); 13237 raw_spin_unlock_irq(&ctx->lock); 13238 free_event(event); 13239 } 13240 13241 /* 13242 * Free a context as created by inheritance by perf_event_init_task() below, 13243 * used by fork() in case of fail. 13244 * 13245 * Even though the task has never lived, the context and events have been 13246 * exposed through the child_list, so we must take care tearing it all down. 13247 */ 13248 void perf_event_free_task(struct task_struct *task) 13249 { 13250 struct perf_event_context *ctx; 13251 struct perf_event *event, *tmp; 13252 13253 ctx = rcu_access_pointer(task->perf_event_ctxp); 13254 if (!ctx) 13255 return; 13256 13257 mutex_lock(&ctx->mutex); 13258 raw_spin_lock_irq(&ctx->lock); 13259 /* 13260 * Destroy the task <-> ctx relation and mark the context dead. 13261 * 13262 * This is important because even though the task hasn't been 13263 * exposed yet the context has been (through child_list). 13264 */ 13265 RCU_INIT_POINTER(task->perf_event_ctxp, NULL); 13266 WRITE_ONCE(ctx->task, TASK_TOMBSTONE); 13267 put_task_struct(task); /* cannot be last */ 13268 raw_spin_unlock_irq(&ctx->lock); 13269 13270 13271 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) 13272 perf_free_event(event, ctx); 13273 13274 mutex_unlock(&ctx->mutex); 13275 13276 /* 13277 * perf_event_release_kernel() could've stolen some of our 13278 * child events and still have them on its free_list. In that 13279 * case we must wait for these events to have been freed (in 13280 * particular all their references to this task must've been 13281 * dropped). 13282 * 13283 * Without this copy_process() will unconditionally free this 13284 * task (irrespective of its reference count) and 13285 * _free_event()'s put_task_struct(event->hw.target) will be a 13286 * use-after-free. 13287 * 13288 * Wait for all events to drop their context reference. 13289 */ 13290 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1); 13291 put_ctx(ctx); /* must be last */ 13292 } 13293 13294 void perf_event_delayed_put(struct task_struct *task) 13295 { 13296 WARN_ON_ONCE(task->perf_event_ctxp); 13297 } 13298 13299 struct file *perf_event_get(unsigned int fd) 13300 { 13301 struct file *file = fget(fd); 13302 if (!file) 13303 return ERR_PTR(-EBADF); 13304 13305 if (file->f_op != &perf_fops) { 13306 fput(file); 13307 return ERR_PTR(-EBADF); 13308 } 13309 13310 return file; 13311 } 13312 13313 const struct perf_event *perf_get_event(struct file *file) 13314 { 13315 if (file->f_op != &perf_fops) 13316 return ERR_PTR(-EINVAL); 13317 13318 return file->private_data; 13319 } 13320 13321 const struct perf_event_attr *perf_event_attrs(struct perf_event *event) 13322 { 13323 if (!event) 13324 return ERR_PTR(-EINVAL); 13325 13326 return &event->attr; 13327 } 13328 13329 /* 13330 * Inherit an event from parent task to child task. 13331 * 13332 * Returns: 13333 * - valid pointer on success 13334 * - NULL for orphaned events 13335 * - IS_ERR() on error 13336 */ 13337 static struct perf_event * 13338 inherit_event(struct perf_event *parent_event, 13339 struct task_struct *parent, 13340 struct perf_event_context *parent_ctx, 13341 struct task_struct *child, 13342 struct perf_event *group_leader, 13343 struct perf_event_context *child_ctx) 13344 { 13345 enum perf_event_state parent_state = parent_event->state; 13346 struct perf_event_pmu_context *pmu_ctx; 13347 struct perf_event *child_event; 13348 unsigned long flags; 13349 13350 /* 13351 * Instead of creating recursive hierarchies of events, 13352 * we link inherited events back to the original parent, 13353 * which has a filp for sure, which we use as the reference 13354 * count: 13355 */ 13356 if (parent_event->parent) 13357 parent_event = parent_event->parent; 13358 13359 child_event = perf_event_alloc(&parent_event->attr, 13360 parent_event->cpu, 13361 child, 13362 group_leader, parent_event, 13363 NULL, NULL, -1); 13364 if (IS_ERR(child_event)) 13365 return child_event; 13366 13367 pmu_ctx = find_get_pmu_context(child_event->pmu, child_ctx, child_event); 13368 if (IS_ERR(pmu_ctx)) { 13369 free_event(child_event); 13370 return ERR_CAST(pmu_ctx); 13371 } 13372 child_event->pmu_ctx = pmu_ctx; 13373 13374 /* 13375 * is_orphaned_event() and list_add_tail(&parent_event->child_list) 13376 * must be under the same lock in order to serialize against 13377 * perf_event_release_kernel(), such that either we must observe 13378 * is_orphaned_event() or they will observe us on the child_list. 13379 */ 13380 mutex_lock(&parent_event->child_mutex); 13381 if (is_orphaned_event(parent_event) || 13382 !atomic_long_inc_not_zero(&parent_event->refcount)) { 13383 mutex_unlock(&parent_event->child_mutex); 13384 /* task_ctx_data is freed with child_ctx */ 13385 free_event(child_event); 13386 return NULL; 13387 } 13388 13389 get_ctx(child_ctx); 13390 13391 /* 13392 * Make the child state follow the state of the parent event, 13393 * not its attr.disabled bit. We hold the parent's mutex, 13394 * so we won't race with perf_event_{en, dis}able_family. 13395 */ 13396 if (parent_state >= PERF_EVENT_STATE_INACTIVE) 13397 child_event->state = PERF_EVENT_STATE_INACTIVE; 13398 else 13399 child_event->state = PERF_EVENT_STATE_OFF; 13400 13401 if (parent_event->attr.freq) { 13402 u64 sample_period = parent_event->hw.sample_period; 13403 struct hw_perf_event *hwc = &child_event->hw; 13404 13405 hwc->sample_period = sample_period; 13406 hwc->last_period = sample_period; 13407 13408 local64_set(&hwc->period_left, sample_period); 13409 } 13410 13411 child_event->ctx = child_ctx; 13412 child_event->overflow_handler = parent_event->overflow_handler; 13413 child_event->overflow_handler_context 13414 = parent_event->overflow_handler_context; 13415 13416 /* 13417 * Precalculate sample_data sizes 13418 */ 13419 perf_event__header_size(child_event); 13420 perf_event__id_header_size(child_event); 13421 13422 /* 13423 * Link it up in the child's context: 13424 */ 13425 raw_spin_lock_irqsave(&child_ctx->lock, flags); 13426 add_event_to_ctx(child_event, child_ctx); 13427 child_event->attach_state |= PERF_ATTACH_CHILD; 13428 raw_spin_unlock_irqrestore(&child_ctx->lock, flags); 13429 13430 /* 13431 * Link this into the parent event's child list 13432 */ 13433 list_add_tail(&child_event->child_list, &parent_event->child_list); 13434 mutex_unlock(&parent_event->child_mutex); 13435 13436 return child_event; 13437 } 13438 13439 /* 13440 * Inherits an event group. 13441 * 13442 * This will quietly suppress orphaned events; !inherit_event() is not an error. 13443 * This matches with perf_event_release_kernel() removing all child events. 13444 * 13445 * Returns: 13446 * - 0 on success 13447 * - <0 on error 13448 */ 13449 static int inherit_group(struct perf_event *parent_event, 13450 struct task_struct *parent, 13451 struct perf_event_context *parent_ctx, 13452 struct task_struct *child, 13453 struct perf_event_context *child_ctx) 13454 { 13455 struct perf_event *leader; 13456 struct perf_event *sub; 13457 struct perf_event *child_ctr; 13458 13459 leader = inherit_event(parent_event, parent, parent_ctx, 13460 child, NULL, child_ctx); 13461 if (IS_ERR(leader)) 13462 return PTR_ERR(leader); 13463 /* 13464 * @leader can be NULL here because of is_orphaned_event(). In this 13465 * case inherit_event() will create individual events, similar to what 13466 * perf_group_detach() would do anyway. 13467 */ 13468 for_each_sibling_event(sub, parent_event) { 13469 child_ctr = inherit_event(sub, parent, parent_ctx, 13470 child, leader, child_ctx); 13471 if (IS_ERR(child_ctr)) 13472 return PTR_ERR(child_ctr); 13473 13474 if (sub->aux_event == parent_event && child_ctr && 13475 !perf_get_aux_event(child_ctr, leader)) 13476 return -EINVAL; 13477 } 13478 if (leader) 13479 leader->group_generation = parent_event->group_generation; 13480 return 0; 13481 } 13482 13483 /* 13484 * Creates the child task context and tries to inherit the event-group. 13485 * 13486 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave 13487 * inherited_all set when we 'fail' to inherit an orphaned event; this is 13488 * consistent with perf_event_release_kernel() removing all child events. 13489 * 13490 * Returns: 13491 * - 0 on success 13492 * - <0 on error 13493 */ 13494 static int 13495 inherit_task_group(struct perf_event *event, struct task_struct *parent, 13496 struct perf_event_context *parent_ctx, 13497 struct task_struct *child, 13498 u64 clone_flags, int *inherited_all) 13499 { 13500 struct perf_event_context *child_ctx; 13501 int ret; 13502 13503 if (!event->attr.inherit || 13504 (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) || 13505 /* Do not inherit if sigtrap and signal handlers were cleared. */ 13506 (event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) { 13507 *inherited_all = 0; 13508 return 0; 13509 } 13510 13511 child_ctx = child->perf_event_ctxp; 13512 if (!child_ctx) { 13513 /* 13514 * This is executed from the parent task context, so 13515 * inherit events that have been marked for cloning. 13516 * First allocate and initialize a context for the 13517 * child. 13518 */ 13519 child_ctx = alloc_perf_context(child); 13520 if (!child_ctx) 13521 return -ENOMEM; 13522 13523 child->perf_event_ctxp = child_ctx; 13524 } 13525 13526 ret = inherit_group(event, parent, parent_ctx, child, child_ctx); 13527 if (ret) 13528 *inherited_all = 0; 13529 13530 return ret; 13531 } 13532 13533 /* 13534 * Initialize the perf_event context in task_struct 13535 */ 13536 static int perf_event_init_context(struct task_struct *child, u64 clone_flags) 13537 { 13538 struct perf_event_context *child_ctx, *parent_ctx; 13539 struct perf_event_context *cloned_ctx; 13540 struct perf_event *event; 13541 struct task_struct *parent = current; 13542 int inherited_all = 1; 13543 unsigned long flags; 13544 int ret = 0; 13545 13546 if (likely(!parent->perf_event_ctxp)) 13547 return 0; 13548 13549 /* 13550 * If the parent's context is a clone, pin it so it won't get 13551 * swapped under us. 13552 */ 13553 parent_ctx = perf_pin_task_context(parent); 13554 if (!parent_ctx) 13555 return 0; 13556 13557 /* 13558 * No need to check if parent_ctx != NULL here; since we saw 13559 * it non-NULL earlier, the only reason for it to become NULL 13560 * is if we exit, and since we're currently in the middle of 13561 * a fork we can't be exiting at the same time. 13562 */ 13563 13564 /* 13565 * Lock the parent list. No need to lock the child - not PID 13566 * hashed yet and not running, so nobody can access it. 13567 */ 13568 mutex_lock(&parent_ctx->mutex); 13569 13570 /* 13571 * We dont have to disable NMIs - we are only looking at 13572 * the list, not manipulating it: 13573 */ 13574 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) { 13575 ret = inherit_task_group(event, parent, parent_ctx, 13576 child, clone_flags, &inherited_all); 13577 if (ret) 13578 goto out_unlock; 13579 } 13580 13581 /* 13582 * We can't hold ctx->lock when iterating the ->flexible_group list due 13583 * to allocations, but we need to prevent rotation because 13584 * rotate_ctx() will change the list from interrupt context. 13585 */ 13586 raw_spin_lock_irqsave(&parent_ctx->lock, flags); 13587 parent_ctx->rotate_disable = 1; 13588 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); 13589 13590 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) { 13591 ret = inherit_task_group(event, parent, parent_ctx, 13592 child, clone_flags, &inherited_all); 13593 if (ret) 13594 goto out_unlock; 13595 } 13596 13597 raw_spin_lock_irqsave(&parent_ctx->lock, flags); 13598 parent_ctx->rotate_disable = 0; 13599 13600 child_ctx = child->perf_event_ctxp; 13601 13602 if (child_ctx && inherited_all) { 13603 /* 13604 * Mark the child context as a clone of the parent 13605 * context, or of whatever the parent is a clone of. 13606 * 13607 * Note that if the parent is a clone, the holding of 13608 * parent_ctx->lock avoids it from being uncloned. 13609 */ 13610 cloned_ctx = parent_ctx->parent_ctx; 13611 if (cloned_ctx) { 13612 child_ctx->parent_ctx = cloned_ctx; 13613 child_ctx->parent_gen = parent_ctx->parent_gen; 13614 } else { 13615 child_ctx->parent_ctx = parent_ctx; 13616 child_ctx->parent_gen = parent_ctx->generation; 13617 } 13618 get_ctx(child_ctx->parent_ctx); 13619 } 13620 13621 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); 13622 out_unlock: 13623 mutex_unlock(&parent_ctx->mutex); 13624 13625 perf_unpin_context(parent_ctx); 13626 put_ctx(parent_ctx); 13627 13628 return ret; 13629 } 13630 13631 /* 13632 * Initialize the perf_event context in task_struct 13633 */ 13634 int perf_event_init_task(struct task_struct *child, u64 clone_flags) 13635 { 13636 int ret; 13637 13638 child->perf_event_ctxp = NULL; 13639 mutex_init(&child->perf_event_mutex); 13640 INIT_LIST_HEAD(&child->perf_event_list); 13641 13642 ret = perf_event_init_context(child, clone_flags); 13643 if (ret) { 13644 perf_event_free_task(child); 13645 return ret; 13646 } 13647 13648 return 0; 13649 } 13650 13651 static void __init perf_event_init_all_cpus(void) 13652 { 13653 struct swevent_htable *swhash; 13654 struct perf_cpu_context *cpuctx; 13655 int cpu; 13656 13657 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL); 13658 13659 for_each_possible_cpu(cpu) { 13660 swhash = &per_cpu(swevent_htable, cpu); 13661 mutex_init(&swhash->hlist_mutex); 13662 13663 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu)); 13664 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu)); 13665 13666 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu)); 13667 13668 cpuctx = per_cpu_ptr(&perf_cpu_context, cpu); 13669 __perf_event_init_context(&cpuctx->ctx); 13670 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex); 13671 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock); 13672 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask); 13673 cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default); 13674 cpuctx->heap = cpuctx->heap_default; 13675 } 13676 } 13677 13678 static void perf_swevent_init_cpu(unsigned int cpu) 13679 { 13680 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 13681 13682 mutex_lock(&swhash->hlist_mutex); 13683 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) { 13684 struct swevent_hlist *hlist; 13685 13686 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu)); 13687 WARN_ON(!hlist); 13688 rcu_assign_pointer(swhash->swevent_hlist, hlist); 13689 } 13690 mutex_unlock(&swhash->hlist_mutex); 13691 } 13692 13693 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE 13694 static void __perf_event_exit_context(void *__info) 13695 { 13696 struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context); 13697 struct perf_event_context *ctx = __info; 13698 struct perf_event *event; 13699 13700 raw_spin_lock(&ctx->lock); 13701 ctx_sched_out(ctx, EVENT_TIME); 13702 list_for_each_entry(event, &ctx->event_list, event_entry) 13703 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP); 13704 raw_spin_unlock(&ctx->lock); 13705 } 13706 13707 static void perf_event_exit_cpu_context(int cpu) 13708 { 13709 struct perf_cpu_context *cpuctx; 13710 struct perf_event_context *ctx; 13711 13712 // XXX simplify cpuctx->online 13713 mutex_lock(&pmus_lock); 13714 cpuctx = per_cpu_ptr(&perf_cpu_context, cpu); 13715 ctx = &cpuctx->ctx; 13716 13717 mutex_lock(&ctx->mutex); 13718 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1); 13719 cpuctx->online = 0; 13720 mutex_unlock(&ctx->mutex); 13721 cpumask_clear_cpu(cpu, perf_online_mask); 13722 mutex_unlock(&pmus_lock); 13723 } 13724 #else 13725 13726 static void perf_event_exit_cpu_context(int cpu) { } 13727 13728 #endif 13729 13730 int perf_event_init_cpu(unsigned int cpu) 13731 { 13732 struct perf_cpu_context *cpuctx; 13733 struct perf_event_context *ctx; 13734 13735 perf_swevent_init_cpu(cpu); 13736 13737 mutex_lock(&pmus_lock); 13738 cpumask_set_cpu(cpu, perf_online_mask); 13739 cpuctx = per_cpu_ptr(&perf_cpu_context, cpu); 13740 ctx = &cpuctx->ctx; 13741 13742 mutex_lock(&ctx->mutex); 13743 cpuctx->online = 1; 13744 mutex_unlock(&ctx->mutex); 13745 mutex_unlock(&pmus_lock); 13746 13747 return 0; 13748 } 13749 13750 int perf_event_exit_cpu(unsigned int cpu) 13751 { 13752 perf_event_exit_cpu_context(cpu); 13753 return 0; 13754 } 13755 13756 static int 13757 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v) 13758 { 13759 int cpu; 13760 13761 for_each_online_cpu(cpu) 13762 perf_event_exit_cpu(cpu); 13763 13764 return NOTIFY_OK; 13765 } 13766 13767 /* 13768 * Run the perf reboot notifier at the very last possible moment so that 13769 * the generic watchdog code runs as long as possible. 13770 */ 13771 static struct notifier_block perf_reboot_notifier = { 13772 .notifier_call = perf_reboot, 13773 .priority = INT_MIN, 13774 }; 13775 13776 void __init perf_event_init(void) 13777 { 13778 int ret; 13779 13780 idr_init(&pmu_idr); 13781 13782 perf_event_init_all_cpus(); 13783 init_srcu_struct(&pmus_srcu); 13784 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE); 13785 perf_pmu_register(&perf_cpu_clock, "cpu_clock", -1); 13786 perf_pmu_register(&perf_task_clock, "task_clock", -1); 13787 perf_tp_register(); 13788 perf_event_init_cpu(smp_processor_id()); 13789 register_reboot_notifier(&perf_reboot_notifier); 13790 13791 ret = init_hw_breakpoint(); 13792 WARN(ret, "hw_breakpoint initialization failed with: %d", ret); 13793 13794 perf_event_cache = KMEM_CACHE(perf_event, SLAB_PANIC); 13795 13796 /* 13797 * Build time assertion that we keep the data_head at the intended 13798 * location. IOW, validation we got the __reserved[] size right. 13799 */ 13800 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head)) 13801 != 1024); 13802 } 13803 13804 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr, 13805 char *page) 13806 { 13807 struct perf_pmu_events_attr *pmu_attr = 13808 container_of(attr, struct perf_pmu_events_attr, attr); 13809 13810 if (pmu_attr->event_str) 13811 return sprintf(page, "%s\n", pmu_attr->event_str); 13812 13813 return 0; 13814 } 13815 EXPORT_SYMBOL_GPL(perf_event_sysfs_show); 13816 13817 static int __init perf_event_sysfs_init(void) 13818 { 13819 struct pmu *pmu; 13820 int ret; 13821 13822 mutex_lock(&pmus_lock); 13823 13824 ret = bus_register(&pmu_bus); 13825 if (ret) 13826 goto unlock; 13827 13828 list_for_each_entry(pmu, &pmus, entry) { 13829 if (pmu->dev) 13830 continue; 13831 13832 ret = pmu_dev_alloc(pmu); 13833 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret); 13834 } 13835 pmu_bus_running = 1; 13836 ret = 0; 13837 13838 unlock: 13839 mutex_unlock(&pmus_lock); 13840 13841 return ret; 13842 } 13843 device_initcall(perf_event_sysfs_init); 13844 13845 #ifdef CONFIG_CGROUP_PERF 13846 static struct cgroup_subsys_state * 13847 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) 13848 { 13849 struct perf_cgroup *jc; 13850 13851 jc = kzalloc(sizeof(*jc), GFP_KERNEL); 13852 if (!jc) 13853 return ERR_PTR(-ENOMEM); 13854 13855 jc->info = alloc_percpu(struct perf_cgroup_info); 13856 if (!jc->info) { 13857 kfree(jc); 13858 return ERR_PTR(-ENOMEM); 13859 } 13860 13861 return &jc->css; 13862 } 13863 13864 static void perf_cgroup_css_free(struct cgroup_subsys_state *css) 13865 { 13866 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css); 13867 13868 free_percpu(jc->info); 13869 kfree(jc); 13870 } 13871 13872 static int perf_cgroup_css_online(struct cgroup_subsys_state *css) 13873 { 13874 perf_event_cgroup(css->cgroup); 13875 return 0; 13876 } 13877 13878 static int __perf_cgroup_move(void *info) 13879 { 13880 struct task_struct *task = info; 13881 13882 preempt_disable(); 13883 perf_cgroup_switch(task); 13884 preempt_enable(); 13885 13886 return 0; 13887 } 13888 13889 static void perf_cgroup_attach(struct cgroup_taskset *tset) 13890 { 13891 struct task_struct *task; 13892 struct cgroup_subsys_state *css; 13893 13894 cgroup_taskset_for_each(task, css, tset) 13895 task_function_call(task, __perf_cgroup_move, task); 13896 } 13897 13898 struct cgroup_subsys perf_event_cgrp_subsys = { 13899 .css_alloc = perf_cgroup_css_alloc, 13900 .css_free = perf_cgroup_css_free, 13901 .css_online = perf_cgroup_css_online, 13902 .attach = perf_cgroup_attach, 13903 /* 13904 * Implicitly enable on dfl hierarchy so that perf events can 13905 * always be filtered by cgroup2 path as long as perf_event 13906 * controller is not mounted on a legacy hierarchy. 13907 */ 13908 .implicit_on_dfl = true, 13909 .threaded = true, 13910 }; 13911 #endif /* CONFIG_CGROUP_PERF */ 13912 13913 DEFINE_STATIC_CALL_RET0(perf_snapshot_branch_stack, perf_snapshot_branch_stack_t); 13914