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