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 58 #include "internal.h" 59 60 #include <asm/irq_regs.h> 61 62 typedef int (*remote_function_f)(void *); 63 64 struct remote_function_call { 65 struct task_struct *p; 66 remote_function_f func; 67 void *info; 68 int ret; 69 }; 70 71 static void remote_function(void *data) 72 { 73 struct remote_function_call *tfc = data; 74 struct task_struct *p = tfc->p; 75 76 if (p) { 77 /* -EAGAIN */ 78 if (task_cpu(p) != smp_processor_id()) 79 return; 80 81 /* 82 * Now that we're on right CPU with IRQs disabled, we can test 83 * if we hit the right task without races. 84 */ 85 86 tfc->ret = -ESRCH; /* No such (running) process */ 87 if (p != current) 88 return; 89 } 90 91 tfc->ret = tfc->func(tfc->info); 92 } 93 94 /** 95 * task_function_call - call a function on the cpu on which a task runs 96 * @p: the task to evaluate 97 * @func: the function to be called 98 * @info: the function call argument 99 * 100 * Calls the function @func when the task is currently running. This might 101 * be on the current CPU, which just calls the function directly. This will 102 * retry due to any failures in smp_call_function_single(), such as if the 103 * task_cpu() goes offline concurrently. 104 * 105 * returns @func return value or -ESRCH or -ENXIO when the process isn't running 106 */ 107 static int 108 task_function_call(struct task_struct *p, remote_function_f func, void *info) 109 { 110 struct remote_function_call data = { 111 .p = p, 112 .func = func, 113 .info = info, 114 .ret = -EAGAIN, 115 }; 116 int ret; 117 118 for (;;) { 119 ret = smp_call_function_single(task_cpu(p), remote_function, 120 &data, 1); 121 if (!ret) 122 ret = data.ret; 123 124 if (ret != -EAGAIN) 125 break; 126 127 cond_resched(); 128 } 129 130 return ret; 131 } 132 133 /** 134 * cpu_function_call - call a function on the cpu 135 * @cpu: target cpu to queue this function 136 * @func: the function to be called 137 * @info: the function call argument 138 * 139 * Calls the function @func on the remote cpu. 140 * 141 * returns: @func return value or -ENXIO when the cpu is offline 142 */ 143 static int cpu_function_call(int cpu, remote_function_f func, void *info) 144 { 145 struct remote_function_call data = { 146 .p = NULL, 147 .func = func, 148 .info = info, 149 .ret = -ENXIO, /* No such CPU */ 150 }; 151 152 smp_call_function_single(cpu, remote_function, &data, 1); 153 154 return data.ret; 155 } 156 157 static inline struct perf_cpu_context * 158 __get_cpu_context(struct perf_event_context *ctx) 159 { 160 return this_cpu_ptr(ctx->pmu->pmu_cpu_context); 161 } 162 163 static void perf_ctx_lock(struct perf_cpu_context *cpuctx, 164 struct perf_event_context *ctx) 165 { 166 raw_spin_lock(&cpuctx->ctx.lock); 167 if (ctx) 168 raw_spin_lock(&ctx->lock); 169 } 170 171 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx, 172 struct perf_event_context *ctx) 173 { 174 if (ctx) 175 raw_spin_unlock(&ctx->lock); 176 raw_spin_unlock(&cpuctx->ctx.lock); 177 } 178 179 #define TASK_TOMBSTONE ((void *)-1L) 180 181 static bool is_kernel_event(struct perf_event *event) 182 { 183 return READ_ONCE(event->owner) == TASK_TOMBSTONE; 184 } 185 186 /* 187 * On task ctx scheduling... 188 * 189 * When !ctx->nr_events a task context will not be scheduled. This means 190 * we can disable the scheduler hooks (for performance) without leaving 191 * pending task ctx state. 192 * 193 * This however results in two special cases: 194 * 195 * - removing the last event from a task ctx; this is relatively straight 196 * forward and is done in __perf_remove_from_context. 197 * 198 * - adding the first event to a task ctx; this is tricky because we cannot 199 * rely on ctx->is_active and therefore cannot use event_function_call(). 200 * See perf_install_in_context(). 201 * 202 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set. 203 */ 204 205 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *, 206 struct perf_event_context *, void *); 207 208 struct event_function_struct { 209 struct perf_event *event; 210 event_f func; 211 void *data; 212 }; 213 214 static int event_function(void *info) 215 { 216 struct event_function_struct *efs = info; 217 struct perf_event *event = efs->event; 218 struct perf_event_context *ctx = event->ctx; 219 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 220 struct perf_event_context *task_ctx = cpuctx->task_ctx; 221 int ret = 0; 222 223 lockdep_assert_irqs_disabled(); 224 225 perf_ctx_lock(cpuctx, task_ctx); 226 /* 227 * Since we do the IPI call without holding ctx->lock things can have 228 * changed, double check we hit the task we set out to hit. 229 */ 230 if (ctx->task) { 231 if (ctx->task != current) { 232 ret = -ESRCH; 233 goto unlock; 234 } 235 236 /* 237 * We only use event_function_call() on established contexts, 238 * and event_function() is only ever called when active (or 239 * rather, we'll have bailed in task_function_call() or the 240 * above ctx->task != current test), therefore we must have 241 * ctx->is_active here. 242 */ 243 WARN_ON_ONCE(!ctx->is_active); 244 /* 245 * And since we have ctx->is_active, cpuctx->task_ctx must 246 * match. 247 */ 248 WARN_ON_ONCE(task_ctx != ctx); 249 } else { 250 WARN_ON_ONCE(&cpuctx->ctx != ctx); 251 } 252 253 efs->func(event, cpuctx, ctx, efs->data); 254 unlock: 255 perf_ctx_unlock(cpuctx, task_ctx); 256 257 return ret; 258 } 259 260 static void event_function_call(struct perf_event *event, event_f func, void *data) 261 { 262 struct perf_event_context *ctx = event->ctx; 263 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */ 264 struct event_function_struct efs = { 265 .event = event, 266 .func = func, 267 .data = data, 268 }; 269 270 if (!event->parent) { 271 /* 272 * If this is a !child event, we must hold ctx::mutex to 273 * stabilize the event->ctx relation. See 274 * perf_event_ctx_lock(). 275 */ 276 lockdep_assert_held(&ctx->mutex); 277 } 278 279 if (!task) { 280 cpu_function_call(event->cpu, event_function, &efs); 281 return; 282 } 283 284 if (task == TASK_TOMBSTONE) 285 return; 286 287 again: 288 if (!task_function_call(task, event_function, &efs)) 289 return; 290 291 raw_spin_lock_irq(&ctx->lock); 292 /* 293 * Reload the task pointer, it might have been changed by 294 * a concurrent perf_event_context_sched_out(). 295 */ 296 task = ctx->task; 297 if (task == TASK_TOMBSTONE) { 298 raw_spin_unlock_irq(&ctx->lock); 299 return; 300 } 301 if (ctx->is_active) { 302 raw_spin_unlock_irq(&ctx->lock); 303 goto again; 304 } 305 func(event, NULL, ctx, data); 306 raw_spin_unlock_irq(&ctx->lock); 307 } 308 309 /* 310 * Similar to event_function_call() + event_function(), but hard assumes IRQs 311 * are already disabled and we're on the right CPU. 312 */ 313 static void event_function_local(struct perf_event *event, event_f func, void *data) 314 { 315 struct perf_event_context *ctx = event->ctx; 316 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 317 struct task_struct *task = READ_ONCE(ctx->task); 318 struct perf_event_context *task_ctx = NULL; 319 320 lockdep_assert_irqs_disabled(); 321 322 if (task) { 323 if (task == TASK_TOMBSTONE) 324 return; 325 326 task_ctx = ctx; 327 } 328 329 perf_ctx_lock(cpuctx, task_ctx); 330 331 task = ctx->task; 332 if (task == TASK_TOMBSTONE) 333 goto unlock; 334 335 if (task) { 336 /* 337 * We must be either inactive or active and the right task, 338 * otherwise we're screwed, since we cannot IPI to somewhere 339 * else. 340 */ 341 if (ctx->is_active) { 342 if (WARN_ON_ONCE(task != current)) 343 goto unlock; 344 345 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx)) 346 goto unlock; 347 } 348 } else { 349 WARN_ON_ONCE(&cpuctx->ctx != ctx); 350 } 351 352 func(event, cpuctx, ctx, data); 353 unlock: 354 perf_ctx_unlock(cpuctx, task_ctx); 355 } 356 357 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\ 358 PERF_FLAG_FD_OUTPUT |\ 359 PERF_FLAG_PID_CGROUP |\ 360 PERF_FLAG_FD_CLOEXEC) 361 362 /* 363 * branch priv levels that need permission checks 364 */ 365 #define PERF_SAMPLE_BRANCH_PERM_PLM \ 366 (PERF_SAMPLE_BRANCH_KERNEL |\ 367 PERF_SAMPLE_BRANCH_HV) 368 369 enum event_type_t { 370 EVENT_FLEXIBLE = 0x1, 371 EVENT_PINNED = 0x2, 372 EVENT_TIME = 0x4, 373 /* see ctx_resched() for details */ 374 EVENT_CPU = 0x8, 375 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED, 376 }; 377 378 /* 379 * perf_sched_events : >0 events exist 380 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu 381 */ 382 383 static void perf_sched_delayed(struct work_struct *work); 384 DEFINE_STATIC_KEY_FALSE(perf_sched_events); 385 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed); 386 static DEFINE_MUTEX(perf_sched_mutex); 387 static atomic_t perf_sched_count; 388 389 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events); 390 static DEFINE_PER_CPU(int, perf_sched_cb_usages); 391 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events); 392 393 static atomic_t nr_mmap_events __read_mostly; 394 static atomic_t nr_comm_events __read_mostly; 395 static atomic_t nr_namespaces_events __read_mostly; 396 static atomic_t nr_task_events __read_mostly; 397 static atomic_t nr_freq_events __read_mostly; 398 static atomic_t nr_switch_events __read_mostly; 399 static atomic_t nr_ksymbol_events __read_mostly; 400 static atomic_t nr_bpf_events __read_mostly; 401 static atomic_t nr_cgroup_events __read_mostly; 402 static atomic_t nr_text_poke_events __read_mostly; 403 static atomic_t nr_build_id_events __read_mostly; 404 405 static LIST_HEAD(pmus); 406 static DEFINE_MUTEX(pmus_lock); 407 static struct srcu_struct pmus_srcu; 408 static cpumask_var_t perf_online_mask; 409 static struct kmem_cache *perf_event_cache; 410 411 /* 412 * perf event paranoia level: 413 * -1 - not paranoid at all 414 * 0 - disallow raw tracepoint access for unpriv 415 * 1 - disallow cpu events for unpriv 416 * 2 - disallow kernel profiling for unpriv 417 */ 418 int sysctl_perf_event_paranoid __read_mostly = 2; 419 420 /* Minimum for 512 kiB + 1 user control page */ 421 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */ 422 423 /* 424 * max perf event sample rate 425 */ 426 #define DEFAULT_MAX_SAMPLE_RATE 100000 427 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE) 428 #define DEFAULT_CPU_TIME_MAX_PERCENT 25 429 430 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE; 431 432 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ); 433 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS; 434 435 static int perf_sample_allowed_ns __read_mostly = 436 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100; 437 438 static void update_perf_cpu_limits(void) 439 { 440 u64 tmp = perf_sample_period_ns; 441 442 tmp *= sysctl_perf_cpu_time_max_percent; 443 tmp = div_u64(tmp, 100); 444 if (!tmp) 445 tmp = 1; 446 447 WRITE_ONCE(perf_sample_allowed_ns, tmp); 448 } 449 450 static bool perf_rotate_context(struct perf_cpu_context *cpuctx); 451 452 int perf_proc_update_handler(struct ctl_table *table, int write, 453 void *buffer, size_t *lenp, loff_t *ppos) 454 { 455 int ret; 456 int perf_cpu = sysctl_perf_cpu_time_max_percent; 457 /* 458 * If throttling is disabled don't allow the write: 459 */ 460 if (write && (perf_cpu == 100 || perf_cpu == 0)) 461 return -EINVAL; 462 463 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); 464 if (ret || !write) 465 return ret; 466 467 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ); 468 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; 469 update_perf_cpu_limits(); 470 471 return 0; 472 } 473 474 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT; 475 476 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write, 477 void *buffer, size_t *lenp, loff_t *ppos) 478 { 479 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); 480 481 if (ret || !write) 482 return ret; 483 484 if (sysctl_perf_cpu_time_max_percent == 100 || 485 sysctl_perf_cpu_time_max_percent == 0) { 486 printk(KERN_WARNING 487 "perf: Dynamic interrupt throttling disabled, can hang your system!\n"); 488 WRITE_ONCE(perf_sample_allowed_ns, 0); 489 } else { 490 update_perf_cpu_limits(); 491 } 492 493 return 0; 494 } 495 496 /* 497 * perf samples are done in some very critical code paths (NMIs). 498 * If they take too much CPU time, the system can lock up and not 499 * get any real work done. This will drop the sample rate when 500 * we detect that events are taking too long. 501 */ 502 #define NR_ACCUMULATED_SAMPLES 128 503 static DEFINE_PER_CPU(u64, running_sample_length); 504 505 static u64 __report_avg; 506 static u64 __report_allowed; 507 508 static void perf_duration_warn(struct irq_work *w) 509 { 510 printk_ratelimited(KERN_INFO 511 "perf: interrupt took too long (%lld > %lld), lowering " 512 "kernel.perf_event_max_sample_rate to %d\n", 513 __report_avg, __report_allowed, 514 sysctl_perf_event_sample_rate); 515 } 516 517 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn); 518 519 void perf_sample_event_took(u64 sample_len_ns) 520 { 521 u64 max_len = READ_ONCE(perf_sample_allowed_ns); 522 u64 running_len; 523 u64 avg_len; 524 u32 max; 525 526 if (max_len == 0) 527 return; 528 529 /* Decay the counter by 1 average sample. */ 530 running_len = __this_cpu_read(running_sample_length); 531 running_len -= running_len/NR_ACCUMULATED_SAMPLES; 532 running_len += sample_len_ns; 533 __this_cpu_write(running_sample_length, running_len); 534 535 /* 536 * Note: this will be biased artifically low until we have 537 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us 538 * from having to maintain a count. 539 */ 540 avg_len = running_len/NR_ACCUMULATED_SAMPLES; 541 if (avg_len <= max_len) 542 return; 543 544 __report_avg = avg_len; 545 __report_allowed = max_len; 546 547 /* 548 * Compute a throttle threshold 25% below the current duration. 549 */ 550 avg_len += avg_len / 4; 551 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent; 552 if (avg_len < max) 553 max /= (u32)avg_len; 554 else 555 max = 1; 556 557 WRITE_ONCE(perf_sample_allowed_ns, avg_len); 558 WRITE_ONCE(max_samples_per_tick, max); 559 560 sysctl_perf_event_sample_rate = max * HZ; 561 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; 562 563 if (!irq_work_queue(&perf_duration_work)) { 564 early_printk("perf: interrupt took too long (%lld > %lld), lowering " 565 "kernel.perf_event_max_sample_rate to %d\n", 566 __report_avg, __report_allowed, 567 sysctl_perf_event_sample_rate); 568 } 569 } 570 571 static atomic64_t perf_event_id; 572 573 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, 574 enum event_type_t event_type); 575 576 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, 577 enum event_type_t event_type, 578 struct task_struct *task); 579 580 static void update_context_time(struct perf_event_context *ctx); 581 static u64 perf_event_time(struct perf_event *event); 582 583 void __weak perf_event_print_debug(void) { } 584 585 static inline u64 perf_clock(void) 586 { 587 return local_clock(); 588 } 589 590 static inline u64 perf_event_clock(struct perf_event *event) 591 { 592 return event->clock(); 593 } 594 595 /* 596 * State based event timekeeping... 597 * 598 * The basic idea is to use event->state to determine which (if any) time 599 * fields to increment with the current delta. This means we only need to 600 * update timestamps when we change state or when they are explicitly requested 601 * (read). 602 * 603 * Event groups make things a little more complicated, but not terribly so. The 604 * rules for a group are that if the group leader is OFF the entire group is 605 * OFF, irrespecive of what the group member states are. This results in 606 * __perf_effective_state(). 607 * 608 * A futher ramification is that when a group leader flips between OFF and 609 * !OFF, we need to update all group member times. 610 * 611 * 612 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we 613 * need to make sure the relevant context time is updated before we try and 614 * update our timestamps. 615 */ 616 617 static __always_inline enum perf_event_state 618 __perf_effective_state(struct perf_event *event) 619 { 620 struct perf_event *leader = event->group_leader; 621 622 if (leader->state <= PERF_EVENT_STATE_OFF) 623 return leader->state; 624 625 return event->state; 626 } 627 628 static __always_inline void 629 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running) 630 { 631 enum perf_event_state state = __perf_effective_state(event); 632 u64 delta = now - event->tstamp; 633 634 *enabled = event->total_time_enabled; 635 if (state >= PERF_EVENT_STATE_INACTIVE) 636 *enabled += delta; 637 638 *running = event->total_time_running; 639 if (state >= PERF_EVENT_STATE_ACTIVE) 640 *running += delta; 641 } 642 643 static void perf_event_update_time(struct perf_event *event) 644 { 645 u64 now = perf_event_time(event); 646 647 __perf_update_times(event, now, &event->total_time_enabled, 648 &event->total_time_running); 649 event->tstamp = now; 650 } 651 652 static void perf_event_update_sibling_time(struct perf_event *leader) 653 { 654 struct perf_event *sibling; 655 656 for_each_sibling_event(sibling, leader) 657 perf_event_update_time(sibling); 658 } 659 660 static void 661 perf_event_set_state(struct perf_event *event, enum perf_event_state state) 662 { 663 if (event->state == state) 664 return; 665 666 perf_event_update_time(event); 667 /* 668 * If a group leader gets enabled/disabled all its siblings 669 * are affected too. 670 */ 671 if ((event->state < 0) ^ (state < 0)) 672 perf_event_update_sibling_time(event); 673 674 WRITE_ONCE(event->state, state); 675 } 676 677 #ifdef CONFIG_CGROUP_PERF 678 679 static inline bool 680 perf_cgroup_match(struct perf_event *event) 681 { 682 struct perf_event_context *ctx = event->ctx; 683 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 684 685 /* @event doesn't care about cgroup */ 686 if (!event->cgrp) 687 return true; 688 689 /* wants specific cgroup scope but @cpuctx isn't associated with any */ 690 if (!cpuctx->cgrp) 691 return false; 692 693 /* 694 * Cgroup scoping is recursive. An event enabled for a cgroup is 695 * also enabled for all its descendant cgroups. If @cpuctx's 696 * cgroup is a descendant of @event's (the test covers identity 697 * case), it's a match. 698 */ 699 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup, 700 event->cgrp->css.cgroup); 701 } 702 703 static inline void perf_detach_cgroup(struct perf_event *event) 704 { 705 css_put(&event->cgrp->css); 706 event->cgrp = NULL; 707 } 708 709 static inline int is_cgroup_event(struct perf_event *event) 710 { 711 return event->cgrp != NULL; 712 } 713 714 static inline u64 perf_cgroup_event_time(struct perf_event *event) 715 { 716 struct perf_cgroup_info *t; 717 718 t = per_cpu_ptr(event->cgrp->info, event->cpu); 719 return t->time; 720 } 721 722 static inline void __update_cgrp_time(struct perf_cgroup *cgrp) 723 { 724 struct perf_cgroup_info *info; 725 u64 now; 726 727 now = perf_clock(); 728 729 info = this_cpu_ptr(cgrp->info); 730 731 info->time += now - info->timestamp; 732 info->timestamp = now; 733 } 734 735 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) 736 { 737 struct perf_cgroup *cgrp = cpuctx->cgrp; 738 struct cgroup_subsys_state *css; 739 740 if (cgrp) { 741 for (css = &cgrp->css; css; css = css->parent) { 742 cgrp = container_of(css, struct perf_cgroup, css); 743 __update_cgrp_time(cgrp); 744 } 745 } 746 } 747 748 static inline void update_cgrp_time_from_event(struct perf_event *event) 749 { 750 struct perf_cgroup *cgrp; 751 752 /* 753 * ensure we access cgroup data only when needed and 754 * when we know the cgroup is pinned (css_get) 755 */ 756 if (!is_cgroup_event(event)) 757 return; 758 759 cgrp = perf_cgroup_from_task(current, event->ctx); 760 /* 761 * Do not update time when cgroup is not active 762 */ 763 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup)) 764 __update_cgrp_time(event->cgrp); 765 } 766 767 static inline void 768 perf_cgroup_set_timestamp(struct task_struct *task, 769 struct perf_event_context *ctx) 770 { 771 struct perf_cgroup *cgrp; 772 struct perf_cgroup_info *info; 773 struct cgroup_subsys_state *css; 774 775 /* 776 * ctx->lock held by caller 777 * ensure we do not access cgroup data 778 * unless we have the cgroup pinned (css_get) 779 */ 780 if (!task || !ctx->nr_cgroups) 781 return; 782 783 cgrp = perf_cgroup_from_task(task, ctx); 784 785 for (css = &cgrp->css; css; css = css->parent) { 786 cgrp = container_of(css, struct perf_cgroup, css); 787 info = this_cpu_ptr(cgrp->info); 788 info->timestamp = ctx->timestamp; 789 } 790 } 791 792 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list); 793 794 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */ 795 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */ 796 797 /* 798 * reschedule events based on the cgroup constraint of task. 799 * 800 * mode SWOUT : schedule out everything 801 * mode SWIN : schedule in based on cgroup for next 802 */ 803 static void perf_cgroup_switch(struct task_struct *task, int mode) 804 { 805 struct perf_cpu_context *cpuctx; 806 struct list_head *list; 807 unsigned long flags; 808 809 /* 810 * Disable interrupts and preemption to avoid this CPU's 811 * cgrp_cpuctx_entry to change under us. 812 */ 813 local_irq_save(flags); 814 815 list = this_cpu_ptr(&cgrp_cpuctx_list); 816 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) { 817 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0); 818 819 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 820 perf_pmu_disable(cpuctx->ctx.pmu); 821 822 if (mode & PERF_CGROUP_SWOUT) { 823 cpu_ctx_sched_out(cpuctx, EVENT_ALL); 824 /* 825 * must not be done before ctxswout due 826 * to event_filter_match() in event_sched_out() 827 */ 828 cpuctx->cgrp = NULL; 829 } 830 831 if (mode & PERF_CGROUP_SWIN) { 832 WARN_ON_ONCE(cpuctx->cgrp); 833 /* 834 * set cgrp before ctxsw in to allow 835 * event_filter_match() to not have to pass 836 * task around 837 * we pass the cpuctx->ctx to perf_cgroup_from_task() 838 * because cgorup events are only per-cpu 839 */ 840 cpuctx->cgrp = perf_cgroup_from_task(task, 841 &cpuctx->ctx); 842 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task); 843 } 844 perf_pmu_enable(cpuctx->ctx.pmu); 845 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 846 } 847 848 local_irq_restore(flags); 849 } 850 851 static inline void perf_cgroup_sched_out(struct task_struct *task, 852 struct task_struct *next) 853 { 854 struct perf_cgroup *cgrp1; 855 struct perf_cgroup *cgrp2 = NULL; 856 857 rcu_read_lock(); 858 /* 859 * we come here when we know perf_cgroup_events > 0 860 * we do not need to pass the ctx here because we know 861 * we are holding the rcu lock 862 */ 863 cgrp1 = perf_cgroup_from_task(task, NULL); 864 cgrp2 = perf_cgroup_from_task(next, NULL); 865 866 /* 867 * only schedule out current cgroup events if we know 868 * that we are switching to a different cgroup. Otherwise, 869 * do no touch the cgroup events. 870 */ 871 if (cgrp1 != cgrp2) 872 perf_cgroup_switch(task, PERF_CGROUP_SWOUT); 873 874 rcu_read_unlock(); 875 } 876 877 static inline void perf_cgroup_sched_in(struct task_struct *prev, 878 struct task_struct *task) 879 { 880 struct perf_cgroup *cgrp1; 881 struct perf_cgroup *cgrp2 = NULL; 882 883 rcu_read_lock(); 884 /* 885 * we come here when we know perf_cgroup_events > 0 886 * we do not need to pass the ctx here because we know 887 * we are holding the rcu lock 888 */ 889 cgrp1 = perf_cgroup_from_task(task, NULL); 890 cgrp2 = perf_cgroup_from_task(prev, NULL); 891 892 /* 893 * only need to schedule in cgroup events if we are changing 894 * cgroup during ctxsw. Cgroup events were not scheduled 895 * out of ctxsw out if that was not the case. 896 */ 897 if (cgrp1 != cgrp2) 898 perf_cgroup_switch(task, PERF_CGROUP_SWIN); 899 900 rcu_read_unlock(); 901 } 902 903 static int perf_cgroup_ensure_storage(struct perf_event *event, 904 struct cgroup_subsys_state *css) 905 { 906 struct perf_cpu_context *cpuctx; 907 struct perf_event **storage; 908 int cpu, heap_size, ret = 0; 909 910 /* 911 * Allow storage to have sufficent space for an iterator for each 912 * possibly nested cgroup plus an iterator for events with no cgroup. 913 */ 914 for (heap_size = 1; css; css = css->parent) 915 heap_size++; 916 917 for_each_possible_cpu(cpu) { 918 cpuctx = per_cpu_ptr(event->pmu->pmu_cpu_context, cpu); 919 if (heap_size <= cpuctx->heap_size) 920 continue; 921 922 storage = kmalloc_node(heap_size * sizeof(struct perf_event *), 923 GFP_KERNEL, cpu_to_node(cpu)); 924 if (!storage) { 925 ret = -ENOMEM; 926 break; 927 } 928 929 raw_spin_lock_irq(&cpuctx->ctx.lock); 930 if (cpuctx->heap_size < heap_size) { 931 swap(cpuctx->heap, storage); 932 if (storage == cpuctx->heap_default) 933 storage = NULL; 934 cpuctx->heap_size = heap_size; 935 } 936 raw_spin_unlock_irq(&cpuctx->ctx.lock); 937 938 kfree(storage); 939 } 940 941 return ret; 942 } 943 944 static inline int perf_cgroup_connect(int fd, struct perf_event *event, 945 struct perf_event_attr *attr, 946 struct perf_event *group_leader) 947 { 948 struct perf_cgroup *cgrp; 949 struct cgroup_subsys_state *css; 950 struct fd f = fdget(fd); 951 int ret = 0; 952 953 if (!f.file) 954 return -EBADF; 955 956 css = css_tryget_online_from_dir(f.file->f_path.dentry, 957 &perf_event_cgrp_subsys); 958 if (IS_ERR(css)) { 959 ret = PTR_ERR(css); 960 goto out; 961 } 962 963 ret = perf_cgroup_ensure_storage(event, css); 964 if (ret) 965 goto out; 966 967 cgrp = container_of(css, struct perf_cgroup, css); 968 event->cgrp = cgrp; 969 970 /* 971 * all events in a group must monitor 972 * the same cgroup because a task belongs 973 * to only one perf cgroup at a time 974 */ 975 if (group_leader && group_leader->cgrp != cgrp) { 976 perf_detach_cgroup(event); 977 ret = -EINVAL; 978 } 979 out: 980 fdput(f); 981 return ret; 982 } 983 984 static inline void 985 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) 986 { 987 struct perf_cgroup_info *t; 988 t = per_cpu_ptr(event->cgrp->info, event->cpu); 989 event->shadow_ctx_time = now - t->timestamp; 990 } 991 992 static inline void 993 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx) 994 { 995 struct perf_cpu_context *cpuctx; 996 997 if (!is_cgroup_event(event)) 998 return; 999 1000 /* 1001 * Because cgroup events are always per-cpu events, 1002 * @ctx == &cpuctx->ctx. 1003 */ 1004 cpuctx = container_of(ctx, struct perf_cpu_context, ctx); 1005 1006 /* 1007 * Since setting cpuctx->cgrp is conditional on the current @cgrp 1008 * matching the event's cgroup, we must do this for every new event, 1009 * because if the first would mismatch, the second would not try again 1010 * and we would leave cpuctx->cgrp unset. 1011 */ 1012 if (ctx->is_active && !cpuctx->cgrp) { 1013 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx); 1014 1015 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup)) 1016 cpuctx->cgrp = cgrp; 1017 } 1018 1019 if (ctx->nr_cgroups++) 1020 return; 1021 1022 list_add(&cpuctx->cgrp_cpuctx_entry, 1023 per_cpu_ptr(&cgrp_cpuctx_list, event->cpu)); 1024 } 1025 1026 static inline void 1027 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx) 1028 { 1029 struct perf_cpu_context *cpuctx; 1030 1031 if (!is_cgroup_event(event)) 1032 return; 1033 1034 /* 1035 * Because cgroup events are always per-cpu events, 1036 * @ctx == &cpuctx->ctx. 1037 */ 1038 cpuctx = container_of(ctx, struct perf_cpu_context, ctx); 1039 1040 if (--ctx->nr_cgroups) 1041 return; 1042 1043 if (ctx->is_active && cpuctx->cgrp) 1044 cpuctx->cgrp = NULL; 1045 1046 list_del(&cpuctx->cgrp_cpuctx_entry); 1047 } 1048 1049 #else /* !CONFIG_CGROUP_PERF */ 1050 1051 static inline bool 1052 perf_cgroup_match(struct perf_event *event) 1053 { 1054 return true; 1055 } 1056 1057 static inline void perf_detach_cgroup(struct perf_event *event) 1058 {} 1059 1060 static inline int is_cgroup_event(struct perf_event *event) 1061 { 1062 return 0; 1063 } 1064 1065 static inline void update_cgrp_time_from_event(struct perf_event *event) 1066 { 1067 } 1068 1069 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) 1070 { 1071 } 1072 1073 static inline void perf_cgroup_sched_out(struct task_struct *task, 1074 struct task_struct *next) 1075 { 1076 } 1077 1078 static inline void perf_cgroup_sched_in(struct task_struct *prev, 1079 struct task_struct *task) 1080 { 1081 } 1082 1083 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event, 1084 struct perf_event_attr *attr, 1085 struct perf_event *group_leader) 1086 { 1087 return -EINVAL; 1088 } 1089 1090 static inline void 1091 perf_cgroup_set_timestamp(struct task_struct *task, 1092 struct perf_event_context *ctx) 1093 { 1094 } 1095 1096 static inline void 1097 perf_cgroup_switch(struct task_struct *task, struct task_struct *next) 1098 { 1099 } 1100 1101 static inline void 1102 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) 1103 { 1104 } 1105 1106 static inline u64 perf_cgroup_event_time(struct perf_event *event) 1107 { 1108 return 0; 1109 } 1110 1111 static inline void 1112 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx) 1113 { 1114 } 1115 1116 static inline void 1117 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx) 1118 { 1119 } 1120 #endif 1121 1122 /* 1123 * set default to be dependent on timer tick just 1124 * like original code 1125 */ 1126 #define PERF_CPU_HRTIMER (1000 / HZ) 1127 /* 1128 * function must be called with interrupts disabled 1129 */ 1130 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr) 1131 { 1132 struct perf_cpu_context *cpuctx; 1133 bool rotations; 1134 1135 lockdep_assert_irqs_disabled(); 1136 1137 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer); 1138 rotations = perf_rotate_context(cpuctx); 1139 1140 raw_spin_lock(&cpuctx->hrtimer_lock); 1141 if (rotations) 1142 hrtimer_forward_now(hr, cpuctx->hrtimer_interval); 1143 else 1144 cpuctx->hrtimer_active = 0; 1145 raw_spin_unlock(&cpuctx->hrtimer_lock); 1146 1147 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART; 1148 } 1149 1150 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu) 1151 { 1152 struct hrtimer *timer = &cpuctx->hrtimer; 1153 struct pmu *pmu = cpuctx->ctx.pmu; 1154 u64 interval; 1155 1156 /* no multiplexing needed for SW PMU */ 1157 if (pmu->task_ctx_nr == perf_sw_context) 1158 return; 1159 1160 /* 1161 * check default is sane, if not set then force to 1162 * default interval (1/tick) 1163 */ 1164 interval = pmu->hrtimer_interval_ms; 1165 if (interval < 1) 1166 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER; 1167 1168 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval); 1169 1170 raw_spin_lock_init(&cpuctx->hrtimer_lock); 1171 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD); 1172 timer->function = perf_mux_hrtimer_handler; 1173 } 1174 1175 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx) 1176 { 1177 struct hrtimer *timer = &cpuctx->hrtimer; 1178 struct pmu *pmu = cpuctx->ctx.pmu; 1179 unsigned long flags; 1180 1181 /* not for SW PMU */ 1182 if (pmu->task_ctx_nr == perf_sw_context) 1183 return 0; 1184 1185 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags); 1186 if (!cpuctx->hrtimer_active) { 1187 cpuctx->hrtimer_active = 1; 1188 hrtimer_forward_now(timer, cpuctx->hrtimer_interval); 1189 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD); 1190 } 1191 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags); 1192 1193 return 0; 1194 } 1195 1196 void perf_pmu_disable(struct pmu *pmu) 1197 { 1198 int *count = this_cpu_ptr(pmu->pmu_disable_count); 1199 if (!(*count)++) 1200 pmu->pmu_disable(pmu); 1201 } 1202 1203 void perf_pmu_enable(struct pmu *pmu) 1204 { 1205 int *count = this_cpu_ptr(pmu->pmu_disable_count); 1206 if (!--(*count)) 1207 pmu->pmu_enable(pmu); 1208 } 1209 1210 static DEFINE_PER_CPU(struct list_head, active_ctx_list); 1211 1212 /* 1213 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and 1214 * perf_event_task_tick() are fully serialized because they're strictly cpu 1215 * affine and perf_event_ctx{activate,deactivate} are called with IRQs 1216 * disabled, while perf_event_task_tick is called from IRQ context. 1217 */ 1218 static void perf_event_ctx_activate(struct perf_event_context *ctx) 1219 { 1220 struct list_head *head = this_cpu_ptr(&active_ctx_list); 1221 1222 lockdep_assert_irqs_disabled(); 1223 1224 WARN_ON(!list_empty(&ctx->active_ctx_list)); 1225 1226 list_add(&ctx->active_ctx_list, head); 1227 } 1228 1229 static void perf_event_ctx_deactivate(struct perf_event_context *ctx) 1230 { 1231 lockdep_assert_irqs_disabled(); 1232 1233 WARN_ON(list_empty(&ctx->active_ctx_list)); 1234 1235 list_del_init(&ctx->active_ctx_list); 1236 } 1237 1238 static void get_ctx(struct perf_event_context *ctx) 1239 { 1240 refcount_inc(&ctx->refcount); 1241 } 1242 1243 static void *alloc_task_ctx_data(struct pmu *pmu) 1244 { 1245 if (pmu->task_ctx_cache) 1246 return kmem_cache_zalloc(pmu->task_ctx_cache, GFP_KERNEL); 1247 1248 return NULL; 1249 } 1250 1251 static void free_task_ctx_data(struct pmu *pmu, void *task_ctx_data) 1252 { 1253 if (pmu->task_ctx_cache && task_ctx_data) 1254 kmem_cache_free(pmu->task_ctx_cache, task_ctx_data); 1255 } 1256 1257 static void free_ctx(struct rcu_head *head) 1258 { 1259 struct perf_event_context *ctx; 1260 1261 ctx = container_of(head, struct perf_event_context, rcu_head); 1262 free_task_ctx_data(ctx->pmu, ctx->task_ctx_data); 1263 kfree(ctx); 1264 } 1265 1266 static void put_ctx(struct perf_event_context *ctx) 1267 { 1268 if (refcount_dec_and_test(&ctx->refcount)) { 1269 if (ctx->parent_ctx) 1270 put_ctx(ctx->parent_ctx); 1271 if (ctx->task && ctx->task != TASK_TOMBSTONE) 1272 put_task_struct(ctx->task); 1273 call_rcu(&ctx->rcu_head, free_ctx); 1274 } 1275 } 1276 1277 /* 1278 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and 1279 * perf_pmu_migrate_context() we need some magic. 1280 * 1281 * Those places that change perf_event::ctx will hold both 1282 * perf_event_ctx::mutex of the 'old' and 'new' ctx value. 1283 * 1284 * Lock ordering is by mutex address. There are two other sites where 1285 * perf_event_context::mutex nests and those are: 1286 * 1287 * - perf_event_exit_task_context() [ child , 0 ] 1288 * perf_event_exit_event() 1289 * put_event() [ parent, 1 ] 1290 * 1291 * - perf_event_init_context() [ parent, 0 ] 1292 * inherit_task_group() 1293 * inherit_group() 1294 * inherit_event() 1295 * perf_event_alloc() 1296 * perf_init_event() 1297 * perf_try_init_event() [ child , 1 ] 1298 * 1299 * While it appears there is an obvious deadlock here -- the parent and child 1300 * nesting levels are inverted between the two. This is in fact safe because 1301 * life-time rules separate them. That is an exiting task cannot fork, and a 1302 * spawning task cannot (yet) exit. 1303 * 1304 * But remember that these are parent<->child context relations, and 1305 * migration does not affect children, therefore these two orderings should not 1306 * interact. 1307 * 1308 * The change in perf_event::ctx does not affect children (as claimed above) 1309 * because the sys_perf_event_open() case will install a new event and break 1310 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only 1311 * concerned with cpuctx and that doesn't have children. 1312 * 1313 * The places that change perf_event::ctx will issue: 1314 * 1315 * perf_remove_from_context(); 1316 * synchronize_rcu(); 1317 * perf_install_in_context(); 1318 * 1319 * to affect the change. The remove_from_context() + synchronize_rcu() should 1320 * quiesce the event, after which we can install it in the new location. This 1321 * means that only external vectors (perf_fops, prctl) can perturb the event 1322 * while in transit. Therefore all such accessors should also acquire 1323 * perf_event_context::mutex to serialize against this. 1324 * 1325 * However; because event->ctx can change while we're waiting to acquire 1326 * ctx->mutex we must be careful and use the below perf_event_ctx_lock() 1327 * function. 1328 * 1329 * Lock order: 1330 * exec_update_lock 1331 * task_struct::perf_event_mutex 1332 * perf_event_context::mutex 1333 * perf_event::child_mutex; 1334 * perf_event_context::lock 1335 * perf_event::mmap_mutex 1336 * mmap_lock 1337 * perf_addr_filters_head::lock 1338 * 1339 * cpu_hotplug_lock 1340 * pmus_lock 1341 * cpuctx->mutex / perf_event_context::mutex 1342 */ 1343 static struct perf_event_context * 1344 perf_event_ctx_lock_nested(struct perf_event *event, int nesting) 1345 { 1346 struct perf_event_context *ctx; 1347 1348 again: 1349 rcu_read_lock(); 1350 ctx = READ_ONCE(event->ctx); 1351 if (!refcount_inc_not_zero(&ctx->refcount)) { 1352 rcu_read_unlock(); 1353 goto again; 1354 } 1355 rcu_read_unlock(); 1356 1357 mutex_lock_nested(&ctx->mutex, nesting); 1358 if (event->ctx != ctx) { 1359 mutex_unlock(&ctx->mutex); 1360 put_ctx(ctx); 1361 goto again; 1362 } 1363 1364 return ctx; 1365 } 1366 1367 static inline struct perf_event_context * 1368 perf_event_ctx_lock(struct perf_event *event) 1369 { 1370 return perf_event_ctx_lock_nested(event, 0); 1371 } 1372 1373 static void perf_event_ctx_unlock(struct perf_event *event, 1374 struct perf_event_context *ctx) 1375 { 1376 mutex_unlock(&ctx->mutex); 1377 put_ctx(ctx); 1378 } 1379 1380 /* 1381 * This must be done under the ctx->lock, such as to serialize against 1382 * context_equiv(), therefore we cannot call put_ctx() since that might end up 1383 * calling scheduler related locks and ctx->lock nests inside those. 1384 */ 1385 static __must_check struct perf_event_context * 1386 unclone_ctx(struct perf_event_context *ctx) 1387 { 1388 struct perf_event_context *parent_ctx = ctx->parent_ctx; 1389 1390 lockdep_assert_held(&ctx->lock); 1391 1392 if (parent_ctx) 1393 ctx->parent_ctx = NULL; 1394 ctx->generation++; 1395 1396 return parent_ctx; 1397 } 1398 1399 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p, 1400 enum pid_type type) 1401 { 1402 u32 nr; 1403 /* 1404 * only top level events have the pid namespace they were created in 1405 */ 1406 if (event->parent) 1407 event = event->parent; 1408 1409 nr = __task_pid_nr_ns(p, type, event->ns); 1410 /* avoid -1 if it is idle thread or runs in another ns */ 1411 if (!nr && !pid_alive(p)) 1412 nr = -1; 1413 return nr; 1414 } 1415 1416 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) 1417 { 1418 return perf_event_pid_type(event, p, PIDTYPE_TGID); 1419 } 1420 1421 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) 1422 { 1423 return perf_event_pid_type(event, p, PIDTYPE_PID); 1424 } 1425 1426 /* 1427 * If we inherit events we want to return the parent event id 1428 * to userspace. 1429 */ 1430 static u64 primary_event_id(struct perf_event *event) 1431 { 1432 u64 id = event->id; 1433 1434 if (event->parent) 1435 id = event->parent->id; 1436 1437 return id; 1438 } 1439 1440 /* 1441 * Get the perf_event_context for a task and lock it. 1442 * 1443 * This has to cope with the fact that until it is locked, 1444 * the context could get moved to another task. 1445 */ 1446 static struct perf_event_context * 1447 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags) 1448 { 1449 struct perf_event_context *ctx; 1450 1451 retry: 1452 /* 1453 * One of the few rules of preemptible RCU is that one cannot do 1454 * rcu_read_unlock() while holding a scheduler (or nested) lock when 1455 * part of the read side critical section was irqs-enabled -- see 1456 * rcu_read_unlock_special(). 1457 * 1458 * Since ctx->lock nests under rq->lock we must ensure the entire read 1459 * side critical section has interrupts disabled. 1460 */ 1461 local_irq_save(*flags); 1462 rcu_read_lock(); 1463 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]); 1464 if (ctx) { 1465 /* 1466 * If this context is a clone of another, it might 1467 * get swapped for another underneath us by 1468 * perf_event_task_sched_out, though the 1469 * rcu_read_lock() protects us from any context 1470 * getting freed. Lock the context and check if it 1471 * got swapped before we could get the lock, and retry 1472 * if so. If we locked the right context, then it 1473 * can't get swapped on us any more. 1474 */ 1475 raw_spin_lock(&ctx->lock); 1476 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) { 1477 raw_spin_unlock(&ctx->lock); 1478 rcu_read_unlock(); 1479 local_irq_restore(*flags); 1480 goto retry; 1481 } 1482 1483 if (ctx->task == TASK_TOMBSTONE || 1484 !refcount_inc_not_zero(&ctx->refcount)) { 1485 raw_spin_unlock(&ctx->lock); 1486 ctx = NULL; 1487 } else { 1488 WARN_ON_ONCE(ctx->task != task); 1489 } 1490 } 1491 rcu_read_unlock(); 1492 if (!ctx) 1493 local_irq_restore(*flags); 1494 return ctx; 1495 } 1496 1497 /* 1498 * Get the context for a task and increment its pin_count so it 1499 * can't get swapped to another task. This also increments its 1500 * reference count so that the context can't get freed. 1501 */ 1502 static struct perf_event_context * 1503 perf_pin_task_context(struct task_struct *task, int ctxn) 1504 { 1505 struct perf_event_context *ctx; 1506 unsigned long flags; 1507 1508 ctx = perf_lock_task_context(task, ctxn, &flags); 1509 if (ctx) { 1510 ++ctx->pin_count; 1511 raw_spin_unlock_irqrestore(&ctx->lock, flags); 1512 } 1513 return ctx; 1514 } 1515 1516 static void perf_unpin_context(struct perf_event_context *ctx) 1517 { 1518 unsigned long flags; 1519 1520 raw_spin_lock_irqsave(&ctx->lock, flags); 1521 --ctx->pin_count; 1522 raw_spin_unlock_irqrestore(&ctx->lock, flags); 1523 } 1524 1525 /* 1526 * Update the record of the current time in a context. 1527 */ 1528 static void update_context_time(struct perf_event_context *ctx) 1529 { 1530 u64 now = perf_clock(); 1531 1532 ctx->time += now - ctx->timestamp; 1533 ctx->timestamp = now; 1534 } 1535 1536 static u64 perf_event_time(struct perf_event *event) 1537 { 1538 struct perf_event_context *ctx = event->ctx; 1539 1540 if (is_cgroup_event(event)) 1541 return perf_cgroup_event_time(event); 1542 1543 return ctx ? ctx->time : 0; 1544 } 1545 1546 static enum event_type_t get_event_type(struct perf_event *event) 1547 { 1548 struct perf_event_context *ctx = event->ctx; 1549 enum event_type_t event_type; 1550 1551 lockdep_assert_held(&ctx->lock); 1552 1553 /* 1554 * It's 'group type', really, because if our group leader is 1555 * pinned, so are we. 1556 */ 1557 if (event->group_leader != event) 1558 event = event->group_leader; 1559 1560 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE; 1561 if (!ctx->task) 1562 event_type |= EVENT_CPU; 1563 1564 return event_type; 1565 } 1566 1567 /* 1568 * Helper function to initialize event group nodes. 1569 */ 1570 static void init_event_group(struct perf_event *event) 1571 { 1572 RB_CLEAR_NODE(&event->group_node); 1573 event->group_index = 0; 1574 } 1575 1576 /* 1577 * Extract pinned or flexible groups from the context 1578 * based on event attrs bits. 1579 */ 1580 static struct perf_event_groups * 1581 get_event_groups(struct perf_event *event, struct perf_event_context *ctx) 1582 { 1583 if (event->attr.pinned) 1584 return &ctx->pinned_groups; 1585 else 1586 return &ctx->flexible_groups; 1587 } 1588 1589 /* 1590 * Helper function to initializes perf_event_group trees. 1591 */ 1592 static void perf_event_groups_init(struct perf_event_groups *groups) 1593 { 1594 groups->tree = RB_ROOT; 1595 groups->index = 0; 1596 } 1597 1598 static inline struct cgroup *event_cgroup(const struct perf_event *event) 1599 { 1600 struct cgroup *cgroup = NULL; 1601 1602 #ifdef CONFIG_CGROUP_PERF 1603 if (event->cgrp) 1604 cgroup = event->cgrp->css.cgroup; 1605 #endif 1606 1607 return cgroup; 1608 } 1609 1610 /* 1611 * Compare function for event groups; 1612 * 1613 * Implements complex key that first sorts by CPU and then by virtual index 1614 * which provides ordering when rotating groups for the same CPU. 1615 */ 1616 static __always_inline int 1617 perf_event_groups_cmp(const int left_cpu, const struct cgroup *left_cgroup, 1618 const u64 left_group_index, const struct perf_event *right) 1619 { 1620 if (left_cpu < right->cpu) 1621 return -1; 1622 if (left_cpu > right->cpu) 1623 return 1; 1624 1625 #ifdef CONFIG_CGROUP_PERF 1626 { 1627 const struct cgroup *right_cgroup = event_cgroup(right); 1628 1629 if (left_cgroup != right_cgroup) { 1630 if (!left_cgroup) { 1631 /* 1632 * Left has no cgroup but right does, no 1633 * cgroups come first. 1634 */ 1635 return -1; 1636 } 1637 if (!right_cgroup) { 1638 /* 1639 * Right has no cgroup but left does, no 1640 * cgroups come first. 1641 */ 1642 return 1; 1643 } 1644 /* Two dissimilar cgroups, order by id. */ 1645 if (cgroup_id(left_cgroup) < cgroup_id(right_cgroup)) 1646 return -1; 1647 1648 return 1; 1649 } 1650 } 1651 #endif 1652 1653 if (left_group_index < right->group_index) 1654 return -1; 1655 if (left_group_index > right->group_index) 1656 return 1; 1657 1658 return 0; 1659 } 1660 1661 #define __node_2_pe(node) \ 1662 rb_entry((node), struct perf_event, group_node) 1663 1664 static inline bool __group_less(struct rb_node *a, const struct rb_node *b) 1665 { 1666 struct perf_event *e = __node_2_pe(a); 1667 return perf_event_groups_cmp(e->cpu, event_cgroup(e), e->group_index, 1668 __node_2_pe(b)) < 0; 1669 } 1670 1671 struct __group_key { 1672 int cpu; 1673 struct cgroup *cgroup; 1674 }; 1675 1676 static inline int __group_cmp(const void *key, const struct rb_node *node) 1677 { 1678 const struct __group_key *a = key; 1679 const struct perf_event *b = __node_2_pe(node); 1680 1681 /* partial/subtree match: @cpu, @cgroup; ignore: @group_index */ 1682 return perf_event_groups_cmp(a->cpu, a->cgroup, b->group_index, b); 1683 } 1684 1685 /* 1686 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for 1687 * key (see perf_event_groups_less). This places it last inside the CPU 1688 * subtree. 1689 */ 1690 static void 1691 perf_event_groups_insert(struct perf_event_groups *groups, 1692 struct perf_event *event) 1693 { 1694 event->group_index = ++groups->index; 1695 1696 rb_add(&event->group_node, &groups->tree, __group_less); 1697 } 1698 1699 /* 1700 * Helper function to insert event into the pinned or flexible groups. 1701 */ 1702 static void 1703 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx) 1704 { 1705 struct perf_event_groups *groups; 1706 1707 groups = get_event_groups(event, ctx); 1708 perf_event_groups_insert(groups, event); 1709 } 1710 1711 /* 1712 * Delete a group from a tree. 1713 */ 1714 static void 1715 perf_event_groups_delete(struct perf_event_groups *groups, 1716 struct perf_event *event) 1717 { 1718 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) || 1719 RB_EMPTY_ROOT(&groups->tree)); 1720 1721 rb_erase(&event->group_node, &groups->tree); 1722 init_event_group(event); 1723 } 1724 1725 /* 1726 * Helper function to delete event from its groups. 1727 */ 1728 static void 1729 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx) 1730 { 1731 struct perf_event_groups *groups; 1732 1733 groups = get_event_groups(event, ctx); 1734 perf_event_groups_delete(groups, event); 1735 } 1736 1737 /* 1738 * Get the leftmost event in the cpu/cgroup subtree. 1739 */ 1740 static struct perf_event * 1741 perf_event_groups_first(struct perf_event_groups *groups, int cpu, 1742 struct cgroup *cgrp) 1743 { 1744 struct __group_key key = { 1745 .cpu = cpu, 1746 .cgroup = cgrp, 1747 }; 1748 struct rb_node *node; 1749 1750 node = rb_find_first(&key, &groups->tree, __group_cmp); 1751 if (node) 1752 return __node_2_pe(node); 1753 1754 return NULL; 1755 } 1756 1757 /* 1758 * Like rb_entry_next_safe() for the @cpu subtree. 1759 */ 1760 static struct perf_event * 1761 perf_event_groups_next(struct perf_event *event) 1762 { 1763 struct __group_key key = { 1764 .cpu = event->cpu, 1765 .cgroup = event_cgroup(event), 1766 }; 1767 struct rb_node *next; 1768 1769 next = rb_next_match(&key, &event->group_node, __group_cmp); 1770 if (next) 1771 return __node_2_pe(next); 1772 1773 return NULL; 1774 } 1775 1776 /* 1777 * Iterate through the whole groups tree. 1778 */ 1779 #define perf_event_groups_for_each(event, groups) \ 1780 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \ 1781 typeof(*event), group_node); event; \ 1782 event = rb_entry_safe(rb_next(&event->group_node), \ 1783 typeof(*event), group_node)) 1784 1785 /* 1786 * Add an event from the lists for its context. 1787 * Must be called with ctx->mutex and ctx->lock held. 1788 */ 1789 static void 1790 list_add_event(struct perf_event *event, struct perf_event_context *ctx) 1791 { 1792 lockdep_assert_held(&ctx->lock); 1793 1794 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); 1795 event->attach_state |= PERF_ATTACH_CONTEXT; 1796 1797 event->tstamp = perf_event_time(event); 1798 1799 /* 1800 * If we're a stand alone event or group leader, we go to the context 1801 * list, group events are kept attached to the group so that 1802 * perf_group_detach can, at all times, locate all siblings. 1803 */ 1804 if (event->group_leader == event) { 1805 event->group_caps = event->event_caps; 1806 add_event_to_groups(event, ctx); 1807 } 1808 1809 list_add_rcu(&event->event_entry, &ctx->event_list); 1810 ctx->nr_events++; 1811 if (event->attr.inherit_stat) 1812 ctx->nr_stat++; 1813 1814 if (event->state > PERF_EVENT_STATE_OFF) 1815 perf_cgroup_event_enable(event, ctx); 1816 1817 ctx->generation++; 1818 } 1819 1820 /* 1821 * Initialize event state based on the perf_event_attr::disabled. 1822 */ 1823 static inline void perf_event__state_init(struct perf_event *event) 1824 { 1825 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF : 1826 PERF_EVENT_STATE_INACTIVE; 1827 } 1828 1829 static void __perf_event_read_size(struct perf_event *event, int nr_siblings) 1830 { 1831 int entry = sizeof(u64); /* value */ 1832 int size = 0; 1833 int nr = 1; 1834 1835 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 1836 size += sizeof(u64); 1837 1838 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 1839 size += sizeof(u64); 1840 1841 if (event->attr.read_format & PERF_FORMAT_ID) 1842 entry += sizeof(u64); 1843 1844 if (event->attr.read_format & PERF_FORMAT_GROUP) { 1845 nr += nr_siblings; 1846 size += sizeof(u64); 1847 } 1848 1849 size += entry * nr; 1850 event->read_size = size; 1851 } 1852 1853 static void __perf_event_header_size(struct perf_event *event, u64 sample_type) 1854 { 1855 struct perf_sample_data *data; 1856 u16 size = 0; 1857 1858 if (sample_type & PERF_SAMPLE_IP) 1859 size += sizeof(data->ip); 1860 1861 if (sample_type & PERF_SAMPLE_ADDR) 1862 size += sizeof(data->addr); 1863 1864 if (sample_type & PERF_SAMPLE_PERIOD) 1865 size += sizeof(data->period); 1866 1867 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE) 1868 size += sizeof(data->weight.full); 1869 1870 if (sample_type & PERF_SAMPLE_READ) 1871 size += event->read_size; 1872 1873 if (sample_type & PERF_SAMPLE_DATA_SRC) 1874 size += sizeof(data->data_src.val); 1875 1876 if (sample_type & PERF_SAMPLE_TRANSACTION) 1877 size += sizeof(data->txn); 1878 1879 if (sample_type & PERF_SAMPLE_PHYS_ADDR) 1880 size += sizeof(data->phys_addr); 1881 1882 if (sample_type & PERF_SAMPLE_CGROUP) 1883 size += sizeof(data->cgroup); 1884 1885 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE) 1886 size += sizeof(data->data_page_size); 1887 1888 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE) 1889 size += sizeof(data->code_page_size); 1890 1891 event->header_size = size; 1892 } 1893 1894 /* 1895 * Called at perf_event creation and when events are attached/detached from a 1896 * group. 1897 */ 1898 static void perf_event__header_size(struct perf_event *event) 1899 { 1900 __perf_event_read_size(event, 1901 event->group_leader->nr_siblings); 1902 __perf_event_header_size(event, event->attr.sample_type); 1903 } 1904 1905 static void perf_event__id_header_size(struct perf_event *event) 1906 { 1907 struct perf_sample_data *data; 1908 u64 sample_type = event->attr.sample_type; 1909 u16 size = 0; 1910 1911 if (sample_type & PERF_SAMPLE_TID) 1912 size += sizeof(data->tid_entry); 1913 1914 if (sample_type & PERF_SAMPLE_TIME) 1915 size += sizeof(data->time); 1916 1917 if (sample_type & PERF_SAMPLE_IDENTIFIER) 1918 size += sizeof(data->id); 1919 1920 if (sample_type & PERF_SAMPLE_ID) 1921 size += sizeof(data->id); 1922 1923 if (sample_type & PERF_SAMPLE_STREAM_ID) 1924 size += sizeof(data->stream_id); 1925 1926 if (sample_type & PERF_SAMPLE_CPU) 1927 size += sizeof(data->cpu_entry); 1928 1929 event->id_header_size = size; 1930 } 1931 1932 static bool perf_event_validate_size(struct perf_event *event) 1933 { 1934 /* 1935 * The values computed here will be over-written when we actually 1936 * attach the event. 1937 */ 1938 __perf_event_read_size(event, event->group_leader->nr_siblings + 1); 1939 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ); 1940 perf_event__id_header_size(event); 1941 1942 /* 1943 * Sum the lot; should not exceed the 64k limit we have on records. 1944 * Conservative limit to allow for callchains and other variable fields. 1945 */ 1946 if (event->read_size + event->header_size + 1947 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024) 1948 return false; 1949 1950 return true; 1951 } 1952 1953 static void perf_group_attach(struct perf_event *event) 1954 { 1955 struct perf_event *group_leader = event->group_leader, *pos; 1956 1957 lockdep_assert_held(&event->ctx->lock); 1958 1959 /* 1960 * We can have double attach due to group movement in perf_event_open. 1961 */ 1962 if (event->attach_state & PERF_ATTACH_GROUP) 1963 return; 1964 1965 event->attach_state |= PERF_ATTACH_GROUP; 1966 1967 if (group_leader == event) 1968 return; 1969 1970 WARN_ON_ONCE(group_leader->ctx != event->ctx); 1971 1972 group_leader->group_caps &= event->event_caps; 1973 1974 list_add_tail(&event->sibling_list, &group_leader->sibling_list); 1975 group_leader->nr_siblings++; 1976 1977 perf_event__header_size(group_leader); 1978 1979 for_each_sibling_event(pos, group_leader) 1980 perf_event__header_size(pos); 1981 } 1982 1983 /* 1984 * Remove an event from the lists for its context. 1985 * Must be called with ctx->mutex and ctx->lock held. 1986 */ 1987 static void 1988 list_del_event(struct perf_event *event, struct perf_event_context *ctx) 1989 { 1990 WARN_ON_ONCE(event->ctx != ctx); 1991 lockdep_assert_held(&ctx->lock); 1992 1993 /* 1994 * We can have double detach due to exit/hot-unplug + close. 1995 */ 1996 if (!(event->attach_state & PERF_ATTACH_CONTEXT)) 1997 return; 1998 1999 event->attach_state &= ~PERF_ATTACH_CONTEXT; 2000 2001 ctx->nr_events--; 2002 if (event->attr.inherit_stat) 2003 ctx->nr_stat--; 2004 2005 list_del_rcu(&event->event_entry); 2006 2007 if (event->group_leader == event) 2008 del_event_from_groups(event, ctx); 2009 2010 /* 2011 * If event was in error state, then keep it 2012 * that way, otherwise bogus counts will be 2013 * returned on read(). The only way to get out 2014 * of error state is by explicit re-enabling 2015 * of the event 2016 */ 2017 if (event->state > PERF_EVENT_STATE_OFF) { 2018 perf_cgroup_event_disable(event, ctx); 2019 perf_event_set_state(event, PERF_EVENT_STATE_OFF); 2020 } 2021 2022 ctx->generation++; 2023 } 2024 2025 static int 2026 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event) 2027 { 2028 if (!has_aux(aux_event)) 2029 return 0; 2030 2031 if (!event->pmu->aux_output_match) 2032 return 0; 2033 2034 return event->pmu->aux_output_match(aux_event); 2035 } 2036 2037 static void put_event(struct perf_event *event); 2038 static void event_sched_out(struct perf_event *event, 2039 struct perf_cpu_context *cpuctx, 2040 struct perf_event_context *ctx); 2041 2042 static void perf_put_aux_event(struct perf_event *event) 2043 { 2044 struct perf_event_context *ctx = event->ctx; 2045 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 2046 struct perf_event *iter; 2047 2048 /* 2049 * If event uses aux_event tear down the link 2050 */ 2051 if (event->aux_event) { 2052 iter = event->aux_event; 2053 event->aux_event = NULL; 2054 put_event(iter); 2055 return; 2056 } 2057 2058 /* 2059 * If the event is an aux_event, tear down all links to 2060 * it from other events. 2061 */ 2062 for_each_sibling_event(iter, event->group_leader) { 2063 if (iter->aux_event != event) 2064 continue; 2065 2066 iter->aux_event = NULL; 2067 put_event(event); 2068 2069 /* 2070 * If it's ACTIVE, schedule it out and put it into ERROR 2071 * state so that we don't try to schedule it again. Note 2072 * that perf_event_enable() will clear the ERROR status. 2073 */ 2074 event_sched_out(iter, cpuctx, ctx); 2075 perf_event_set_state(event, PERF_EVENT_STATE_ERROR); 2076 } 2077 } 2078 2079 static bool perf_need_aux_event(struct perf_event *event) 2080 { 2081 return !!event->attr.aux_output || !!event->attr.aux_sample_size; 2082 } 2083 2084 static int perf_get_aux_event(struct perf_event *event, 2085 struct perf_event *group_leader) 2086 { 2087 /* 2088 * Our group leader must be an aux event if we want to be 2089 * an aux_output. This way, the aux event will precede its 2090 * aux_output events in the group, and therefore will always 2091 * schedule first. 2092 */ 2093 if (!group_leader) 2094 return 0; 2095 2096 /* 2097 * aux_output and aux_sample_size are mutually exclusive. 2098 */ 2099 if (event->attr.aux_output && event->attr.aux_sample_size) 2100 return 0; 2101 2102 if (event->attr.aux_output && 2103 !perf_aux_output_match(event, group_leader)) 2104 return 0; 2105 2106 if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux) 2107 return 0; 2108 2109 if (!atomic_long_inc_not_zero(&group_leader->refcount)) 2110 return 0; 2111 2112 /* 2113 * Link aux_outputs to their aux event; this is undone in 2114 * perf_group_detach() by perf_put_aux_event(). When the 2115 * group in torn down, the aux_output events loose their 2116 * link to the aux_event and can't schedule any more. 2117 */ 2118 event->aux_event = group_leader; 2119 2120 return 1; 2121 } 2122 2123 static inline struct list_head *get_event_list(struct perf_event *event) 2124 { 2125 struct perf_event_context *ctx = event->ctx; 2126 return event->attr.pinned ? &ctx->pinned_active : &ctx->flexible_active; 2127 } 2128 2129 /* 2130 * Events that have PERF_EV_CAP_SIBLING require being part of a group and 2131 * cannot exist on their own, schedule them out and move them into the ERROR 2132 * state. Also see _perf_event_enable(), it will not be able to recover 2133 * this ERROR state. 2134 */ 2135 static inline void perf_remove_sibling_event(struct perf_event *event) 2136 { 2137 struct perf_event_context *ctx = event->ctx; 2138 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 2139 2140 event_sched_out(event, cpuctx, ctx); 2141 perf_event_set_state(event, PERF_EVENT_STATE_ERROR); 2142 } 2143 2144 static void perf_group_detach(struct perf_event *event) 2145 { 2146 struct perf_event *leader = event->group_leader; 2147 struct perf_event *sibling, *tmp; 2148 struct perf_event_context *ctx = event->ctx; 2149 2150 lockdep_assert_held(&ctx->lock); 2151 2152 /* 2153 * We can have double detach due to exit/hot-unplug + close. 2154 */ 2155 if (!(event->attach_state & PERF_ATTACH_GROUP)) 2156 return; 2157 2158 event->attach_state &= ~PERF_ATTACH_GROUP; 2159 2160 perf_put_aux_event(event); 2161 2162 /* 2163 * If this is a sibling, remove it from its group. 2164 */ 2165 if (leader != event) { 2166 list_del_init(&event->sibling_list); 2167 event->group_leader->nr_siblings--; 2168 goto out; 2169 } 2170 2171 /* 2172 * If this was a group event with sibling events then 2173 * upgrade the siblings to singleton events by adding them 2174 * to whatever list we are on. 2175 */ 2176 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) { 2177 2178 if (sibling->event_caps & PERF_EV_CAP_SIBLING) 2179 perf_remove_sibling_event(sibling); 2180 2181 sibling->group_leader = sibling; 2182 list_del_init(&sibling->sibling_list); 2183 2184 /* Inherit group flags from the previous leader */ 2185 sibling->group_caps = event->group_caps; 2186 2187 if (!RB_EMPTY_NODE(&event->group_node)) { 2188 add_event_to_groups(sibling, event->ctx); 2189 2190 if (sibling->state == PERF_EVENT_STATE_ACTIVE) 2191 list_add_tail(&sibling->active_list, get_event_list(sibling)); 2192 } 2193 2194 WARN_ON_ONCE(sibling->ctx != event->ctx); 2195 } 2196 2197 out: 2198 for_each_sibling_event(tmp, leader) 2199 perf_event__header_size(tmp); 2200 2201 perf_event__header_size(leader); 2202 } 2203 2204 static void sync_child_event(struct perf_event *child_event); 2205 2206 static void perf_child_detach(struct perf_event *event) 2207 { 2208 struct perf_event *parent_event = event->parent; 2209 2210 if (!(event->attach_state & PERF_ATTACH_CHILD)) 2211 return; 2212 2213 event->attach_state &= ~PERF_ATTACH_CHILD; 2214 2215 if (WARN_ON_ONCE(!parent_event)) 2216 return; 2217 2218 lockdep_assert_held(&parent_event->child_mutex); 2219 2220 sync_child_event(event); 2221 list_del_init(&event->child_list); 2222 } 2223 2224 static bool is_orphaned_event(struct perf_event *event) 2225 { 2226 return event->state == PERF_EVENT_STATE_DEAD; 2227 } 2228 2229 static inline int __pmu_filter_match(struct perf_event *event) 2230 { 2231 struct pmu *pmu = event->pmu; 2232 return pmu->filter_match ? pmu->filter_match(event) : 1; 2233 } 2234 2235 /* 2236 * Check whether we should attempt to schedule an event group based on 2237 * PMU-specific filtering. An event group can consist of HW and SW events, 2238 * potentially with a SW leader, so we must check all the filters, to 2239 * determine whether a group is schedulable: 2240 */ 2241 static inline int pmu_filter_match(struct perf_event *event) 2242 { 2243 struct perf_event *sibling; 2244 2245 if (!__pmu_filter_match(event)) 2246 return 0; 2247 2248 for_each_sibling_event(sibling, event) { 2249 if (!__pmu_filter_match(sibling)) 2250 return 0; 2251 } 2252 2253 return 1; 2254 } 2255 2256 static inline int 2257 event_filter_match(struct perf_event *event) 2258 { 2259 return (event->cpu == -1 || event->cpu == smp_processor_id()) && 2260 perf_cgroup_match(event) && pmu_filter_match(event); 2261 } 2262 2263 static void 2264 event_sched_out(struct perf_event *event, 2265 struct perf_cpu_context *cpuctx, 2266 struct perf_event_context *ctx) 2267 { 2268 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE; 2269 2270 WARN_ON_ONCE(event->ctx != ctx); 2271 lockdep_assert_held(&ctx->lock); 2272 2273 if (event->state != PERF_EVENT_STATE_ACTIVE) 2274 return; 2275 2276 /* 2277 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but 2278 * we can schedule events _OUT_ individually through things like 2279 * __perf_remove_from_context(). 2280 */ 2281 list_del_init(&event->active_list); 2282 2283 perf_pmu_disable(event->pmu); 2284 2285 event->pmu->del(event, 0); 2286 event->oncpu = -1; 2287 2288 if (READ_ONCE(event->pending_disable) >= 0) { 2289 WRITE_ONCE(event->pending_disable, -1); 2290 perf_cgroup_event_disable(event, ctx); 2291 state = PERF_EVENT_STATE_OFF; 2292 } 2293 perf_event_set_state(event, state); 2294 2295 if (!is_software_event(event)) 2296 cpuctx->active_oncpu--; 2297 if (!--ctx->nr_active) 2298 perf_event_ctx_deactivate(ctx); 2299 if (event->attr.freq && event->attr.sample_freq) 2300 ctx->nr_freq--; 2301 if (event->attr.exclusive || !cpuctx->active_oncpu) 2302 cpuctx->exclusive = 0; 2303 2304 perf_pmu_enable(event->pmu); 2305 } 2306 2307 static void 2308 group_sched_out(struct perf_event *group_event, 2309 struct perf_cpu_context *cpuctx, 2310 struct perf_event_context *ctx) 2311 { 2312 struct perf_event *event; 2313 2314 if (group_event->state != PERF_EVENT_STATE_ACTIVE) 2315 return; 2316 2317 perf_pmu_disable(ctx->pmu); 2318 2319 event_sched_out(group_event, cpuctx, ctx); 2320 2321 /* 2322 * Schedule out siblings (if any): 2323 */ 2324 for_each_sibling_event(event, group_event) 2325 event_sched_out(event, cpuctx, ctx); 2326 2327 perf_pmu_enable(ctx->pmu); 2328 } 2329 2330 #define DETACH_GROUP 0x01UL 2331 #define DETACH_CHILD 0x02UL 2332 2333 /* 2334 * Cross CPU call to remove a performance event 2335 * 2336 * We disable the event on the hardware level first. After that we 2337 * remove it from the context list. 2338 */ 2339 static void 2340 __perf_remove_from_context(struct perf_event *event, 2341 struct perf_cpu_context *cpuctx, 2342 struct perf_event_context *ctx, 2343 void *info) 2344 { 2345 unsigned long flags = (unsigned long)info; 2346 2347 if (ctx->is_active & EVENT_TIME) { 2348 update_context_time(ctx); 2349 update_cgrp_time_from_cpuctx(cpuctx); 2350 } 2351 2352 event_sched_out(event, cpuctx, ctx); 2353 if (flags & DETACH_GROUP) 2354 perf_group_detach(event); 2355 if (flags & DETACH_CHILD) 2356 perf_child_detach(event); 2357 list_del_event(event, ctx); 2358 2359 if (!ctx->nr_events && ctx->is_active) { 2360 ctx->is_active = 0; 2361 ctx->rotate_necessary = 0; 2362 if (ctx->task) { 2363 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 2364 cpuctx->task_ctx = NULL; 2365 } 2366 } 2367 } 2368 2369 /* 2370 * Remove the event from a task's (or a CPU's) list of events. 2371 * 2372 * If event->ctx is a cloned context, callers must make sure that 2373 * every task struct that event->ctx->task could possibly point to 2374 * remains valid. This is OK when called from perf_release since 2375 * that only calls us on the top-level context, which can't be a clone. 2376 * When called from perf_event_exit_task, it's OK because the 2377 * context has been detached from its task. 2378 */ 2379 static void perf_remove_from_context(struct perf_event *event, unsigned long flags) 2380 { 2381 struct perf_event_context *ctx = event->ctx; 2382 2383 lockdep_assert_held(&ctx->mutex); 2384 2385 /* 2386 * Because of perf_event_exit_task(), perf_remove_from_context() ought 2387 * to work in the face of TASK_TOMBSTONE, unlike every other 2388 * event_function_call() user. 2389 */ 2390 raw_spin_lock_irq(&ctx->lock); 2391 if (!ctx->is_active) { 2392 __perf_remove_from_context(event, __get_cpu_context(ctx), 2393 ctx, (void *)flags); 2394 raw_spin_unlock_irq(&ctx->lock); 2395 return; 2396 } 2397 raw_spin_unlock_irq(&ctx->lock); 2398 2399 event_function_call(event, __perf_remove_from_context, (void *)flags); 2400 } 2401 2402 /* 2403 * Cross CPU call to disable a performance event 2404 */ 2405 static void __perf_event_disable(struct perf_event *event, 2406 struct perf_cpu_context *cpuctx, 2407 struct perf_event_context *ctx, 2408 void *info) 2409 { 2410 if (event->state < PERF_EVENT_STATE_INACTIVE) 2411 return; 2412 2413 if (ctx->is_active & EVENT_TIME) { 2414 update_context_time(ctx); 2415 update_cgrp_time_from_event(event); 2416 } 2417 2418 if (event == event->group_leader) 2419 group_sched_out(event, cpuctx, ctx); 2420 else 2421 event_sched_out(event, cpuctx, ctx); 2422 2423 perf_event_set_state(event, PERF_EVENT_STATE_OFF); 2424 perf_cgroup_event_disable(event, ctx); 2425 } 2426 2427 /* 2428 * Disable an event. 2429 * 2430 * If event->ctx is a cloned context, callers must make sure that 2431 * every task struct that event->ctx->task could possibly point to 2432 * remains valid. This condition is satisfied when called through 2433 * perf_event_for_each_child or perf_event_for_each because they 2434 * hold the top-level event's child_mutex, so any descendant that 2435 * goes to exit will block in perf_event_exit_event(). 2436 * 2437 * When called from perf_pending_event it's OK because event->ctx 2438 * is the current context on this CPU and preemption is disabled, 2439 * hence we can't get into perf_event_task_sched_out for this context. 2440 */ 2441 static void _perf_event_disable(struct perf_event *event) 2442 { 2443 struct perf_event_context *ctx = event->ctx; 2444 2445 raw_spin_lock_irq(&ctx->lock); 2446 if (event->state <= PERF_EVENT_STATE_OFF) { 2447 raw_spin_unlock_irq(&ctx->lock); 2448 return; 2449 } 2450 raw_spin_unlock_irq(&ctx->lock); 2451 2452 event_function_call(event, __perf_event_disable, NULL); 2453 } 2454 2455 void perf_event_disable_local(struct perf_event *event) 2456 { 2457 event_function_local(event, __perf_event_disable, NULL); 2458 } 2459 2460 /* 2461 * Strictly speaking kernel users cannot create groups and therefore this 2462 * interface does not need the perf_event_ctx_lock() magic. 2463 */ 2464 void perf_event_disable(struct perf_event *event) 2465 { 2466 struct perf_event_context *ctx; 2467 2468 ctx = perf_event_ctx_lock(event); 2469 _perf_event_disable(event); 2470 perf_event_ctx_unlock(event, ctx); 2471 } 2472 EXPORT_SYMBOL_GPL(perf_event_disable); 2473 2474 void perf_event_disable_inatomic(struct perf_event *event) 2475 { 2476 WRITE_ONCE(event->pending_disable, smp_processor_id()); 2477 /* can fail, see perf_pending_event_disable() */ 2478 irq_work_queue(&event->pending); 2479 } 2480 2481 static void perf_set_shadow_time(struct perf_event *event, 2482 struct perf_event_context *ctx) 2483 { 2484 /* 2485 * use the correct time source for the time snapshot 2486 * 2487 * We could get by without this by leveraging the 2488 * fact that to get to this function, the caller 2489 * has most likely already called update_context_time() 2490 * and update_cgrp_time_xx() and thus both timestamp 2491 * are identical (or very close). Given that tstamp is, 2492 * already adjusted for cgroup, we could say that: 2493 * tstamp - ctx->timestamp 2494 * is equivalent to 2495 * tstamp - cgrp->timestamp. 2496 * 2497 * Then, in perf_output_read(), the calculation would 2498 * work with no changes because: 2499 * - event is guaranteed scheduled in 2500 * - no scheduled out in between 2501 * - thus the timestamp would be the same 2502 * 2503 * But this is a bit hairy. 2504 * 2505 * So instead, we have an explicit cgroup call to remain 2506 * within the time source all along. We believe it 2507 * is cleaner and simpler to understand. 2508 */ 2509 if (is_cgroup_event(event)) 2510 perf_cgroup_set_shadow_time(event, event->tstamp); 2511 else 2512 event->shadow_ctx_time = event->tstamp - ctx->timestamp; 2513 } 2514 2515 #define MAX_INTERRUPTS (~0ULL) 2516 2517 static void perf_log_throttle(struct perf_event *event, int enable); 2518 static void perf_log_itrace_start(struct perf_event *event); 2519 2520 static int 2521 event_sched_in(struct perf_event *event, 2522 struct perf_cpu_context *cpuctx, 2523 struct perf_event_context *ctx) 2524 { 2525 int ret = 0; 2526 2527 WARN_ON_ONCE(event->ctx != ctx); 2528 2529 lockdep_assert_held(&ctx->lock); 2530 2531 if (event->state <= PERF_EVENT_STATE_OFF) 2532 return 0; 2533 2534 WRITE_ONCE(event->oncpu, smp_processor_id()); 2535 /* 2536 * Order event::oncpu write to happen before the ACTIVE state is 2537 * visible. This allows perf_event_{stop,read}() to observe the correct 2538 * ->oncpu if it sees ACTIVE. 2539 */ 2540 smp_wmb(); 2541 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE); 2542 2543 /* 2544 * Unthrottle events, since we scheduled we might have missed several 2545 * ticks already, also for a heavily scheduling task there is little 2546 * guarantee it'll get a tick in a timely manner. 2547 */ 2548 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) { 2549 perf_log_throttle(event, 1); 2550 event->hw.interrupts = 0; 2551 } 2552 2553 perf_pmu_disable(event->pmu); 2554 2555 perf_set_shadow_time(event, ctx); 2556 2557 perf_log_itrace_start(event); 2558 2559 if (event->pmu->add(event, PERF_EF_START)) { 2560 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE); 2561 event->oncpu = -1; 2562 ret = -EAGAIN; 2563 goto out; 2564 } 2565 2566 if (!is_software_event(event)) 2567 cpuctx->active_oncpu++; 2568 if (!ctx->nr_active++) 2569 perf_event_ctx_activate(ctx); 2570 if (event->attr.freq && event->attr.sample_freq) 2571 ctx->nr_freq++; 2572 2573 if (event->attr.exclusive) 2574 cpuctx->exclusive = 1; 2575 2576 out: 2577 perf_pmu_enable(event->pmu); 2578 2579 return ret; 2580 } 2581 2582 static int 2583 group_sched_in(struct perf_event *group_event, 2584 struct perf_cpu_context *cpuctx, 2585 struct perf_event_context *ctx) 2586 { 2587 struct perf_event *event, *partial_group = NULL; 2588 struct pmu *pmu = ctx->pmu; 2589 2590 if (group_event->state == PERF_EVENT_STATE_OFF) 2591 return 0; 2592 2593 pmu->start_txn(pmu, PERF_PMU_TXN_ADD); 2594 2595 if (event_sched_in(group_event, cpuctx, ctx)) 2596 goto error; 2597 2598 /* 2599 * Schedule in siblings as one group (if any): 2600 */ 2601 for_each_sibling_event(event, group_event) { 2602 if (event_sched_in(event, cpuctx, ctx)) { 2603 partial_group = event; 2604 goto group_error; 2605 } 2606 } 2607 2608 if (!pmu->commit_txn(pmu)) 2609 return 0; 2610 2611 group_error: 2612 /* 2613 * Groups can be scheduled in as one unit only, so undo any 2614 * partial group before returning: 2615 * The events up to the failed event are scheduled out normally. 2616 */ 2617 for_each_sibling_event(event, group_event) { 2618 if (event == partial_group) 2619 break; 2620 2621 event_sched_out(event, cpuctx, ctx); 2622 } 2623 event_sched_out(group_event, cpuctx, ctx); 2624 2625 error: 2626 pmu->cancel_txn(pmu); 2627 return -EAGAIN; 2628 } 2629 2630 /* 2631 * Work out whether we can put this event group on the CPU now. 2632 */ 2633 static int group_can_go_on(struct perf_event *event, 2634 struct perf_cpu_context *cpuctx, 2635 int can_add_hw) 2636 { 2637 /* 2638 * Groups consisting entirely of software events can always go on. 2639 */ 2640 if (event->group_caps & PERF_EV_CAP_SOFTWARE) 2641 return 1; 2642 /* 2643 * If an exclusive group is already on, no other hardware 2644 * events can go on. 2645 */ 2646 if (cpuctx->exclusive) 2647 return 0; 2648 /* 2649 * If this group is exclusive and there are already 2650 * events on the CPU, it can't go on. 2651 */ 2652 if (event->attr.exclusive && !list_empty(get_event_list(event))) 2653 return 0; 2654 /* 2655 * Otherwise, try to add it if all previous groups were able 2656 * to go on. 2657 */ 2658 return can_add_hw; 2659 } 2660 2661 static void add_event_to_ctx(struct perf_event *event, 2662 struct perf_event_context *ctx) 2663 { 2664 list_add_event(event, ctx); 2665 perf_group_attach(event); 2666 } 2667 2668 static void ctx_sched_out(struct perf_event_context *ctx, 2669 struct perf_cpu_context *cpuctx, 2670 enum event_type_t event_type); 2671 static void 2672 ctx_sched_in(struct perf_event_context *ctx, 2673 struct perf_cpu_context *cpuctx, 2674 enum event_type_t event_type, 2675 struct task_struct *task); 2676 2677 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx, 2678 struct perf_event_context *ctx, 2679 enum event_type_t event_type) 2680 { 2681 if (!cpuctx->task_ctx) 2682 return; 2683 2684 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx)) 2685 return; 2686 2687 ctx_sched_out(ctx, cpuctx, event_type); 2688 } 2689 2690 static void perf_event_sched_in(struct perf_cpu_context *cpuctx, 2691 struct perf_event_context *ctx, 2692 struct task_struct *task) 2693 { 2694 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task); 2695 if (ctx) 2696 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task); 2697 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task); 2698 if (ctx) 2699 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task); 2700 } 2701 2702 /* 2703 * We want to maintain the following priority of scheduling: 2704 * - CPU pinned (EVENT_CPU | EVENT_PINNED) 2705 * - task pinned (EVENT_PINNED) 2706 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE) 2707 * - task flexible (EVENT_FLEXIBLE). 2708 * 2709 * In order to avoid unscheduling and scheduling back in everything every 2710 * time an event is added, only do it for the groups of equal priority and 2711 * below. 2712 * 2713 * This can be called after a batch operation on task events, in which case 2714 * event_type is a bit mask of the types of events involved. For CPU events, 2715 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE. 2716 */ 2717 static void ctx_resched(struct perf_cpu_context *cpuctx, 2718 struct perf_event_context *task_ctx, 2719 enum event_type_t event_type) 2720 { 2721 enum event_type_t ctx_event_type; 2722 bool cpu_event = !!(event_type & EVENT_CPU); 2723 2724 /* 2725 * If pinned groups are involved, flexible groups also need to be 2726 * scheduled out. 2727 */ 2728 if (event_type & EVENT_PINNED) 2729 event_type |= EVENT_FLEXIBLE; 2730 2731 ctx_event_type = event_type & EVENT_ALL; 2732 2733 perf_pmu_disable(cpuctx->ctx.pmu); 2734 if (task_ctx) 2735 task_ctx_sched_out(cpuctx, task_ctx, event_type); 2736 2737 /* 2738 * Decide which cpu ctx groups to schedule out based on the types 2739 * of events that caused rescheduling: 2740 * - EVENT_CPU: schedule out corresponding groups; 2741 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups; 2742 * - otherwise, do nothing more. 2743 */ 2744 if (cpu_event) 2745 cpu_ctx_sched_out(cpuctx, ctx_event_type); 2746 else if (ctx_event_type & EVENT_PINNED) 2747 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); 2748 2749 perf_event_sched_in(cpuctx, task_ctx, current); 2750 perf_pmu_enable(cpuctx->ctx.pmu); 2751 } 2752 2753 void perf_pmu_resched(struct pmu *pmu) 2754 { 2755 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 2756 struct perf_event_context *task_ctx = cpuctx->task_ctx; 2757 2758 perf_ctx_lock(cpuctx, task_ctx); 2759 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU); 2760 perf_ctx_unlock(cpuctx, task_ctx); 2761 } 2762 2763 /* 2764 * Cross CPU call to install and enable a performance event 2765 * 2766 * Very similar to remote_function() + event_function() but cannot assume that 2767 * things like ctx->is_active and cpuctx->task_ctx are set. 2768 */ 2769 static int __perf_install_in_context(void *info) 2770 { 2771 struct perf_event *event = info; 2772 struct perf_event_context *ctx = event->ctx; 2773 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 2774 struct perf_event_context *task_ctx = cpuctx->task_ctx; 2775 bool reprogram = true; 2776 int ret = 0; 2777 2778 raw_spin_lock(&cpuctx->ctx.lock); 2779 if (ctx->task) { 2780 raw_spin_lock(&ctx->lock); 2781 task_ctx = ctx; 2782 2783 reprogram = (ctx->task == current); 2784 2785 /* 2786 * If the task is running, it must be running on this CPU, 2787 * otherwise we cannot reprogram things. 2788 * 2789 * If its not running, we don't care, ctx->lock will 2790 * serialize against it becoming runnable. 2791 */ 2792 if (task_curr(ctx->task) && !reprogram) { 2793 ret = -ESRCH; 2794 goto unlock; 2795 } 2796 2797 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx); 2798 } else if (task_ctx) { 2799 raw_spin_lock(&task_ctx->lock); 2800 } 2801 2802 #ifdef CONFIG_CGROUP_PERF 2803 if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) { 2804 /* 2805 * If the current cgroup doesn't match the event's 2806 * cgroup, we should not try to schedule it. 2807 */ 2808 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx); 2809 reprogram = cgroup_is_descendant(cgrp->css.cgroup, 2810 event->cgrp->css.cgroup); 2811 } 2812 #endif 2813 2814 if (reprogram) { 2815 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 2816 add_event_to_ctx(event, ctx); 2817 ctx_resched(cpuctx, task_ctx, get_event_type(event)); 2818 } else { 2819 add_event_to_ctx(event, ctx); 2820 } 2821 2822 unlock: 2823 perf_ctx_unlock(cpuctx, task_ctx); 2824 2825 return ret; 2826 } 2827 2828 static bool exclusive_event_installable(struct perf_event *event, 2829 struct perf_event_context *ctx); 2830 2831 /* 2832 * Attach a performance event to a context. 2833 * 2834 * Very similar to event_function_call, see comment there. 2835 */ 2836 static void 2837 perf_install_in_context(struct perf_event_context *ctx, 2838 struct perf_event *event, 2839 int cpu) 2840 { 2841 struct task_struct *task = READ_ONCE(ctx->task); 2842 2843 lockdep_assert_held(&ctx->mutex); 2844 2845 WARN_ON_ONCE(!exclusive_event_installable(event, ctx)); 2846 2847 if (event->cpu != -1) 2848 event->cpu = cpu; 2849 2850 /* 2851 * Ensures that if we can observe event->ctx, both the event and ctx 2852 * will be 'complete'. See perf_iterate_sb_cpu(). 2853 */ 2854 smp_store_release(&event->ctx, ctx); 2855 2856 /* 2857 * perf_event_attr::disabled events will not run and can be initialized 2858 * without IPI. Except when this is the first event for the context, in 2859 * that case we need the magic of the IPI to set ctx->is_active. 2860 * 2861 * The IOC_ENABLE that is sure to follow the creation of a disabled 2862 * event will issue the IPI and reprogram the hardware. 2863 */ 2864 if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF && ctx->nr_events) { 2865 raw_spin_lock_irq(&ctx->lock); 2866 if (ctx->task == TASK_TOMBSTONE) { 2867 raw_spin_unlock_irq(&ctx->lock); 2868 return; 2869 } 2870 add_event_to_ctx(event, ctx); 2871 raw_spin_unlock_irq(&ctx->lock); 2872 return; 2873 } 2874 2875 if (!task) { 2876 cpu_function_call(cpu, __perf_install_in_context, event); 2877 return; 2878 } 2879 2880 /* 2881 * Should not happen, we validate the ctx is still alive before calling. 2882 */ 2883 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) 2884 return; 2885 2886 /* 2887 * Installing events is tricky because we cannot rely on ctx->is_active 2888 * to be set in case this is the nr_events 0 -> 1 transition. 2889 * 2890 * Instead we use task_curr(), which tells us if the task is running. 2891 * However, since we use task_curr() outside of rq::lock, we can race 2892 * against the actual state. This means the result can be wrong. 2893 * 2894 * If we get a false positive, we retry, this is harmless. 2895 * 2896 * If we get a false negative, things are complicated. If we are after 2897 * perf_event_context_sched_in() ctx::lock will serialize us, and the 2898 * value must be correct. If we're before, it doesn't matter since 2899 * perf_event_context_sched_in() will program the counter. 2900 * 2901 * However, this hinges on the remote context switch having observed 2902 * our task->perf_event_ctxp[] store, such that it will in fact take 2903 * ctx::lock in perf_event_context_sched_in(). 2904 * 2905 * We do this by task_function_call(), if the IPI fails to hit the task 2906 * we know any future context switch of task must see the 2907 * perf_event_ctpx[] store. 2908 */ 2909 2910 /* 2911 * This smp_mb() orders the task->perf_event_ctxp[] store with the 2912 * task_cpu() load, such that if the IPI then does not find the task 2913 * running, a future context switch of that task must observe the 2914 * store. 2915 */ 2916 smp_mb(); 2917 again: 2918 if (!task_function_call(task, __perf_install_in_context, event)) 2919 return; 2920 2921 raw_spin_lock_irq(&ctx->lock); 2922 task = ctx->task; 2923 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) { 2924 /* 2925 * Cannot happen because we already checked above (which also 2926 * cannot happen), and we hold ctx->mutex, which serializes us 2927 * against perf_event_exit_task_context(). 2928 */ 2929 raw_spin_unlock_irq(&ctx->lock); 2930 return; 2931 } 2932 /* 2933 * If the task is not running, ctx->lock will avoid it becoming so, 2934 * thus we can safely install the event. 2935 */ 2936 if (task_curr(task)) { 2937 raw_spin_unlock_irq(&ctx->lock); 2938 goto again; 2939 } 2940 add_event_to_ctx(event, ctx); 2941 raw_spin_unlock_irq(&ctx->lock); 2942 } 2943 2944 /* 2945 * Cross CPU call to enable a performance event 2946 */ 2947 static void __perf_event_enable(struct perf_event *event, 2948 struct perf_cpu_context *cpuctx, 2949 struct perf_event_context *ctx, 2950 void *info) 2951 { 2952 struct perf_event *leader = event->group_leader; 2953 struct perf_event_context *task_ctx; 2954 2955 if (event->state >= PERF_EVENT_STATE_INACTIVE || 2956 event->state <= PERF_EVENT_STATE_ERROR) 2957 return; 2958 2959 if (ctx->is_active) 2960 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 2961 2962 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE); 2963 perf_cgroup_event_enable(event, ctx); 2964 2965 if (!ctx->is_active) 2966 return; 2967 2968 if (!event_filter_match(event)) { 2969 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current); 2970 return; 2971 } 2972 2973 /* 2974 * If the event is in a group and isn't the group leader, 2975 * then don't put it on unless the group is on. 2976 */ 2977 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) { 2978 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current); 2979 return; 2980 } 2981 2982 task_ctx = cpuctx->task_ctx; 2983 if (ctx->task) 2984 WARN_ON_ONCE(task_ctx != ctx); 2985 2986 ctx_resched(cpuctx, task_ctx, get_event_type(event)); 2987 } 2988 2989 /* 2990 * Enable an event. 2991 * 2992 * If event->ctx is a cloned context, callers must make sure that 2993 * every task struct that event->ctx->task could possibly point to 2994 * remains valid. This condition is satisfied when called through 2995 * perf_event_for_each_child or perf_event_for_each as described 2996 * for perf_event_disable. 2997 */ 2998 static void _perf_event_enable(struct perf_event *event) 2999 { 3000 struct perf_event_context *ctx = event->ctx; 3001 3002 raw_spin_lock_irq(&ctx->lock); 3003 if (event->state >= PERF_EVENT_STATE_INACTIVE || 3004 event->state < PERF_EVENT_STATE_ERROR) { 3005 out: 3006 raw_spin_unlock_irq(&ctx->lock); 3007 return; 3008 } 3009 3010 /* 3011 * If the event is in error state, clear that first. 3012 * 3013 * That way, if we see the event in error state below, we know that it 3014 * has gone back into error state, as distinct from the task having 3015 * been scheduled away before the cross-call arrived. 3016 */ 3017 if (event->state == PERF_EVENT_STATE_ERROR) { 3018 /* 3019 * Detached SIBLING events cannot leave ERROR state. 3020 */ 3021 if (event->event_caps & PERF_EV_CAP_SIBLING && 3022 event->group_leader == event) 3023 goto out; 3024 3025 event->state = PERF_EVENT_STATE_OFF; 3026 } 3027 raw_spin_unlock_irq(&ctx->lock); 3028 3029 event_function_call(event, __perf_event_enable, NULL); 3030 } 3031 3032 /* 3033 * See perf_event_disable(); 3034 */ 3035 void perf_event_enable(struct perf_event *event) 3036 { 3037 struct perf_event_context *ctx; 3038 3039 ctx = perf_event_ctx_lock(event); 3040 _perf_event_enable(event); 3041 perf_event_ctx_unlock(event, ctx); 3042 } 3043 EXPORT_SYMBOL_GPL(perf_event_enable); 3044 3045 struct stop_event_data { 3046 struct perf_event *event; 3047 unsigned int restart; 3048 }; 3049 3050 static int __perf_event_stop(void *info) 3051 { 3052 struct stop_event_data *sd = info; 3053 struct perf_event *event = sd->event; 3054 3055 /* if it's already INACTIVE, do nothing */ 3056 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) 3057 return 0; 3058 3059 /* matches smp_wmb() in event_sched_in() */ 3060 smp_rmb(); 3061 3062 /* 3063 * There is a window with interrupts enabled before we get here, 3064 * so we need to check again lest we try to stop another CPU's event. 3065 */ 3066 if (READ_ONCE(event->oncpu) != smp_processor_id()) 3067 return -EAGAIN; 3068 3069 event->pmu->stop(event, PERF_EF_UPDATE); 3070 3071 /* 3072 * May race with the actual stop (through perf_pmu_output_stop()), 3073 * but it is only used for events with AUX ring buffer, and such 3074 * events will refuse to restart because of rb::aux_mmap_count==0, 3075 * see comments in perf_aux_output_begin(). 3076 * 3077 * Since this is happening on an event-local CPU, no trace is lost 3078 * while restarting. 3079 */ 3080 if (sd->restart) 3081 event->pmu->start(event, 0); 3082 3083 return 0; 3084 } 3085 3086 static int perf_event_stop(struct perf_event *event, int restart) 3087 { 3088 struct stop_event_data sd = { 3089 .event = event, 3090 .restart = restart, 3091 }; 3092 int ret = 0; 3093 3094 do { 3095 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) 3096 return 0; 3097 3098 /* matches smp_wmb() in event_sched_in() */ 3099 smp_rmb(); 3100 3101 /* 3102 * We only want to restart ACTIVE events, so if the event goes 3103 * inactive here (event->oncpu==-1), there's nothing more to do; 3104 * fall through with ret==-ENXIO. 3105 */ 3106 ret = cpu_function_call(READ_ONCE(event->oncpu), 3107 __perf_event_stop, &sd); 3108 } while (ret == -EAGAIN); 3109 3110 return ret; 3111 } 3112 3113 /* 3114 * In order to contain the amount of racy and tricky in the address filter 3115 * configuration management, it is a two part process: 3116 * 3117 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below, 3118 * we update the addresses of corresponding vmas in 3119 * event::addr_filter_ranges array and bump the event::addr_filters_gen; 3120 * (p2) when an event is scheduled in (pmu::add), it calls 3121 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync() 3122 * if the generation has changed since the previous call. 3123 * 3124 * If (p1) happens while the event is active, we restart it to force (p2). 3125 * 3126 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on 3127 * pre-existing mappings, called once when new filters arrive via SET_FILTER 3128 * ioctl; 3129 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly 3130 * registered mapping, called for every new mmap(), with mm::mmap_lock down 3131 * for reading; 3132 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process 3133 * of exec. 3134 */ 3135 void perf_event_addr_filters_sync(struct perf_event *event) 3136 { 3137 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 3138 3139 if (!has_addr_filter(event)) 3140 return; 3141 3142 raw_spin_lock(&ifh->lock); 3143 if (event->addr_filters_gen != event->hw.addr_filters_gen) { 3144 event->pmu->addr_filters_sync(event); 3145 event->hw.addr_filters_gen = event->addr_filters_gen; 3146 } 3147 raw_spin_unlock(&ifh->lock); 3148 } 3149 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync); 3150 3151 static int _perf_event_refresh(struct perf_event *event, int refresh) 3152 { 3153 /* 3154 * not supported on inherited events 3155 */ 3156 if (event->attr.inherit || !is_sampling_event(event)) 3157 return -EINVAL; 3158 3159 atomic_add(refresh, &event->event_limit); 3160 _perf_event_enable(event); 3161 3162 return 0; 3163 } 3164 3165 /* 3166 * See perf_event_disable() 3167 */ 3168 int perf_event_refresh(struct perf_event *event, int refresh) 3169 { 3170 struct perf_event_context *ctx; 3171 int ret; 3172 3173 ctx = perf_event_ctx_lock(event); 3174 ret = _perf_event_refresh(event, refresh); 3175 perf_event_ctx_unlock(event, ctx); 3176 3177 return ret; 3178 } 3179 EXPORT_SYMBOL_GPL(perf_event_refresh); 3180 3181 static int perf_event_modify_breakpoint(struct perf_event *bp, 3182 struct perf_event_attr *attr) 3183 { 3184 int err; 3185 3186 _perf_event_disable(bp); 3187 3188 err = modify_user_hw_breakpoint_check(bp, attr, true); 3189 3190 if (!bp->attr.disabled) 3191 _perf_event_enable(bp); 3192 3193 return err; 3194 } 3195 3196 static int perf_event_modify_attr(struct perf_event *event, 3197 struct perf_event_attr *attr) 3198 { 3199 int (*func)(struct perf_event *, struct perf_event_attr *); 3200 struct perf_event *child; 3201 int err; 3202 3203 if (event->attr.type != attr->type) 3204 return -EINVAL; 3205 3206 switch (event->attr.type) { 3207 case PERF_TYPE_BREAKPOINT: 3208 func = perf_event_modify_breakpoint; 3209 break; 3210 default: 3211 /* Place holder for future additions. */ 3212 return -EOPNOTSUPP; 3213 } 3214 3215 WARN_ON_ONCE(event->ctx->parent_ctx); 3216 3217 mutex_lock(&event->child_mutex); 3218 err = func(event, attr); 3219 if (err) 3220 goto out; 3221 list_for_each_entry(child, &event->child_list, child_list) { 3222 err = func(child, attr); 3223 if (err) 3224 goto out; 3225 } 3226 out: 3227 mutex_unlock(&event->child_mutex); 3228 return err; 3229 } 3230 3231 static void ctx_sched_out(struct perf_event_context *ctx, 3232 struct perf_cpu_context *cpuctx, 3233 enum event_type_t event_type) 3234 { 3235 struct perf_event *event, *tmp; 3236 int is_active = ctx->is_active; 3237 3238 lockdep_assert_held(&ctx->lock); 3239 3240 if (likely(!ctx->nr_events)) { 3241 /* 3242 * See __perf_remove_from_context(). 3243 */ 3244 WARN_ON_ONCE(ctx->is_active); 3245 if (ctx->task) 3246 WARN_ON_ONCE(cpuctx->task_ctx); 3247 return; 3248 } 3249 3250 ctx->is_active &= ~event_type; 3251 if (!(ctx->is_active & EVENT_ALL)) 3252 ctx->is_active = 0; 3253 3254 if (ctx->task) { 3255 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 3256 if (!ctx->is_active) 3257 cpuctx->task_ctx = NULL; 3258 } 3259 3260 /* 3261 * Always update time if it was set; not only when it changes. 3262 * Otherwise we can 'forget' to update time for any but the last 3263 * context we sched out. For example: 3264 * 3265 * ctx_sched_out(.event_type = EVENT_FLEXIBLE) 3266 * ctx_sched_out(.event_type = EVENT_PINNED) 3267 * 3268 * would only update time for the pinned events. 3269 */ 3270 if (is_active & EVENT_TIME) { 3271 /* update (and stop) ctx time */ 3272 update_context_time(ctx); 3273 update_cgrp_time_from_cpuctx(cpuctx); 3274 } 3275 3276 is_active ^= ctx->is_active; /* changed bits */ 3277 3278 if (!ctx->nr_active || !(is_active & EVENT_ALL)) 3279 return; 3280 3281 perf_pmu_disable(ctx->pmu); 3282 if (is_active & EVENT_PINNED) { 3283 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list) 3284 group_sched_out(event, cpuctx, ctx); 3285 } 3286 3287 if (is_active & EVENT_FLEXIBLE) { 3288 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list) 3289 group_sched_out(event, cpuctx, ctx); 3290 3291 /* 3292 * Since we cleared EVENT_FLEXIBLE, also clear 3293 * rotate_necessary, is will be reset by 3294 * ctx_flexible_sched_in() when needed. 3295 */ 3296 ctx->rotate_necessary = 0; 3297 } 3298 perf_pmu_enable(ctx->pmu); 3299 } 3300 3301 /* 3302 * Test whether two contexts are equivalent, i.e. whether they have both been 3303 * cloned from the same version of the same context. 3304 * 3305 * Equivalence is measured using a generation number in the context that is 3306 * incremented on each modification to it; see unclone_ctx(), list_add_event() 3307 * and list_del_event(). 3308 */ 3309 static int context_equiv(struct perf_event_context *ctx1, 3310 struct perf_event_context *ctx2) 3311 { 3312 lockdep_assert_held(&ctx1->lock); 3313 lockdep_assert_held(&ctx2->lock); 3314 3315 /* Pinning disables the swap optimization */ 3316 if (ctx1->pin_count || ctx2->pin_count) 3317 return 0; 3318 3319 /* If ctx1 is the parent of ctx2 */ 3320 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen) 3321 return 1; 3322 3323 /* If ctx2 is the parent of ctx1 */ 3324 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation) 3325 return 1; 3326 3327 /* 3328 * If ctx1 and ctx2 have the same parent; we flatten the parent 3329 * hierarchy, see perf_event_init_context(). 3330 */ 3331 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx && 3332 ctx1->parent_gen == ctx2->parent_gen) 3333 return 1; 3334 3335 /* Unmatched */ 3336 return 0; 3337 } 3338 3339 static void __perf_event_sync_stat(struct perf_event *event, 3340 struct perf_event *next_event) 3341 { 3342 u64 value; 3343 3344 if (!event->attr.inherit_stat) 3345 return; 3346 3347 /* 3348 * Update the event value, we cannot use perf_event_read() 3349 * because we're in the middle of a context switch and have IRQs 3350 * disabled, which upsets smp_call_function_single(), however 3351 * we know the event must be on the current CPU, therefore we 3352 * don't need to use it. 3353 */ 3354 if (event->state == PERF_EVENT_STATE_ACTIVE) 3355 event->pmu->read(event); 3356 3357 perf_event_update_time(event); 3358 3359 /* 3360 * In order to keep per-task stats reliable we need to flip the event 3361 * values when we flip the contexts. 3362 */ 3363 value = local64_read(&next_event->count); 3364 value = local64_xchg(&event->count, value); 3365 local64_set(&next_event->count, value); 3366 3367 swap(event->total_time_enabled, next_event->total_time_enabled); 3368 swap(event->total_time_running, next_event->total_time_running); 3369 3370 /* 3371 * Since we swizzled the values, update the user visible data too. 3372 */ 3373 perf_event_update_userpage(event); 3374 perf_event_update_userpage(next_event); 3375 } 3376 3377 static void perf_event_sync_stat(struct perf_event_context *ctx, 3378 struct perf_event_context *next_ctx) 3379 { 3380 struct perf_event *event, *next_event; 3381 3382 if (!ctx->nr_stat) 3383 return; 3384 3385 update_context_time(ctx); 3386 3387 event = list_first_entry(&ctx->event_list, 3388 struct perf_event, event_entry); 3389 3390 next_event = list_first_entry(&next_ctx->event_list, 3391 struct perf_event, event_entry); 3392 3393 while (&event->event_entry != &ctx->event_list && 3394 &next_event->event_entry != &next_ctx->event_list) { 3395 3396 __perf_event_sync_stat(event, next_event); 3397 3398 event = list_next_entry(event, event_entry); 3399 next_event = list_next_entry(next_event, event_entry); 3400 } 3401 } 3402 3403 static void perf_event_context_sched_out(struct task_struct *task, int ctxn, 3404 struct task_struct *next) 3405 { 3406 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn]; 3407 struct perf_event_context *next_ctx; 3408 struct perf_event_context *parent, *next_parent; 3409 struct perf_cpu_context *cpuctx; 3410 int do_switch = 1; 3411 struct pmu *pmu; 3412 3413 if (likely(!ctx)) 3414 return; 3415 3416 pmu = ctx->pmu; 3417 cpuctx = __get_cpu_context(ctx); 3418 if (!cpuctx->task_ctx) 3419 return; 3420 3421 rcu_read_lock(); 3422 next_ctx = next->perf_event_ctxp[ctxn]; 3423 if (!next_ctx) 3424 goto unlock; 3425 3426 parent = rcu_dereference(ctx->parent_ctx); 3427 next_parent = rcu_dereference(next_ctx->parent_ctx); 3428 3429 /* If neither context have a parent context; they cannot be clones. */ 3430 if (!parent && !next_parent) 3431 goto unlock; 3432 3433 if (next_parent == ctx || next_ctx == parent || next_parent == parent) { 3434 /* 3435 * Looks like the two contexts are clones, so we might be 3436 * able to optimize the context switch. We lock both 3437 * contexts and check that they are clones under the 3438 * lock (including re-checking that neither has been 3439 * uncloned in the meantime). It doesn't matter which 3440 * order we take the locks because no other cpu could 3441 * be trying to lock both of these tasks. 3442 */ 3443 raw_spin_lock(&ctx->lock); 3444 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING); 3445 if (context_equiv(ctx, next_ctx)) { 3446 3447 WRITE_ONCE(ctx->task, next); 3448 WRITE_ONCE(next_ctx->task, task); 3449 3450 perf_pmu_disable(pmu); 3451 3452 if (cpuctx->sched_cb_usage && pmu->sched_task) 3453 pmu->sched_task(ctx, false); 3454 3455 /* 3456 * PMU specific parts of task perf context can require 3457 * additional synchronization. As an example of such 3458 * synchronization see implementation details of Intel 3459 * LBR call stack data profiling; 3460 */ 3461 if (pmu->swap_task_ctx) 3462 pmu->swap_task_ctx(ctx, next_ctx); 3463 else 3464 swap(ctx->task_ctx_data, next_ctx->task_ctx_data); 3465 3466 perf_pmu_enable(pmu); 3467 3468 /* 3469 * RCU_INIT_POINTER here is safe because we've not 3470 * modified the ctx and the above modification of 3471 * ctx->task and ctx->task_ctx_data are immaterial 3472 * since those values are always verified under 3473 * ctx->lock which we're now holding. 3474 */ 3475 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx); 3476 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx); 3477 3478 do_switch = 0; 3479 3480 perf_event_sync_stat(ctx, next_ctx); 3481 } 3482 raw_spin_unlock(&next_ctx->lock); 3483 raw_spin_unlock(&ctx->lock); 3484 } 3485 unlock: 3486 rcu_read_unlock(); 3487 3488 if (do_switch) { 3489 raw_spin_lock(&ctx->lock); 3490 perf_pmu_disable(pmu); 3491 3492 if (cpuctx->sched_cb_usage && pmu->sched_task) 3493 pmu->sched_task(ctx, false); 3494 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL); 3495 3496 perf_pmu_enable(pmu); 3497 raw_spin_unlock(&ctx->lock); 3498 } 3499 } 3500 3501 static DEFINE_PER_CPU(struct list_head, sched_cb_list); 3502 3503 void perf_sched_cb_dec(struct pmu *pmu) 3504 { 3505 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 3506 3507 this_cpu_dec(perf_sched_cb_usages); 3508 3509 if (!--cpuctx->sched_cb_usage) 3510 list_del(&cpuctx->sched_cb_entry); 3511 } 3512 3513 3514 void perf_sched_cb_inc(struct pmu *pmu) 3515 { 3516 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 3517 3518 if (!cpuctx->sched_cb_usage++) 3519 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list)); 3520 3521 this_cpu_inc(perf_sched_cb_usages); 3522 } 3523 3524 /* 3525 * This function provides the context switch callback to the lower code 3526 * layer. It is invoked ONLY when the context switch callback is enabled. 3527 * 3528 * This callback is relevant even to per-cpu events; for example multi event 3529 * PEBS requires this to provide PID/TID information. This requires we flush 3530 * all queued PEBS records before we context switch to a new task. 3531 */ 3532 static void __perf_pmu_sched_task(struct perf_cpu_context *cpuctx, bool sched_in) 3533 { 3534 struct pmu *pmu; 3535 3536 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */ 3537 3538 if (WARN_ON_ONCE(!pmu->sched_task)) 3539 return; 3540 3541 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 3542 perf_pmu_disable(pmu); 3543 3544 pmu->sched_task(cpuctx->task_ctx, sched_in); 3545 3546 perf_pmu_enable(pmu); 3547 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 3548 } 3549 3550 static void perf_pmu_sched_task(struct task_struct *prev, 3551 struct task_struct *next, 3552 bool sched_in) 3553 { 3554 struct perf_cpu_context *cpuctx; 3555 3556 if (prev == next) 3557 return; 3558 3559 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) { 3560 /* will be handled in perf_event_context_sched_in/out */ 3561 if (cpuctx->task_ctx) 3562 continue; 3563 3564 __perf_pmu_sched_task(cpuctx, sched_in); 3565 } 3566 } 3567 3568 static void perf_event_switch(struct task_struct *task, 3569 struct task_struct *next_prev, bool sched_in); 3570 3571 #define for_each_task_context_nr(ctxn) \ 3572 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++) 3573 3574 /* 3575 * Called from scheduler to remove the events of the current task, 3576 * with interrupts disabled. 3577 * 3578 * We stop each event and update the event value in event->count. 3579 * 3580 * This does not protect us against NMI, but disable() 3581 * sets the disabled bit in the control field of event _before_ 3582 * accessing the event control register. If a NMI hits, then it will 3583 * not restart the event. 3584 */ 3585 void __perf_event_task_sched_out(struct task_struct *task, 3586 struct task_struct *next) 3587 { 3588 int ctxn; 3589 3590 if (__this_cpu_read(perf_sched_cb_usages)) 3591 perf_pmu_sched_task(task, next, false); 3592 3593 if (atomic_read(&nr_switch_events)) 3594 perf_event_switch(task, next, false); 3595 3596 for_each_task_context_nr(ctxn) 3597 perf_event_context_sched_out(task, ctxn, next); 3598 3599 /* 3600 * if cgroup events exist on this CPU, then we need 3601 * to check if we have to switch out PMU state. 3602 * cgroup event are system-wide mode only 3603 */ 3604 if (atomic_read(this_cpu_ptr(&perf_cgroup_events))) 3605 perf_cgroup_sched_out(task, next); 3606 } 3607 3608 /* 3609 * Called with IRQs disabled 3610 */ 3611 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, 3612 enum event_type_t event_type) 3613 { 3614 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type); 3615 } 3616 3617 static bool perf_less_group_idx(const void *l, const void *r) 3618 { 3619 const struct perf_event *le = *(const struct perf_event **)l; 3620 const struct perf_event *re = *(const struct perf_event **)r; 3621 3622 return le->group_index < re->group_index; 3623 } 3624 3625 static void swap_ptr(void *l, void *r) 3626 { 3627 void **lp = l, **rp = r; 3628 3629 swap(*lp, *rp); 3630 } 3631 3632 static const struct min_heap_callbacks perf_min_heap = { 3633 .elem_size = sizeof(struct perf_event *), 3634 .less = perf_less_group_idx, 3635 .swp = swap_ptr, 3636 }; 3637 3638 static void __heap_add(struct min_heap *heap, struct perf_event *event) 3639 { 3640 struct perf_event **itrs = heap->data; 3641 3642 if (event) { 3643 itrs[heap->nr] = event; 3644 heap->nr++; 3645 } 3646 } 3647 3648 static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx, 3649 struct perf_event_groups *groups, int cpu, 3650 int (*func)(struct perf_event *, void *), 3651 void *data) 3652 { 3653 #ifdef CONFIG_CGROUP_PERF 3654 struct cgroup_subsys_state *css = NULL; 3655 #endif 3656 /* Space for per CPU and/or any CPU event iterators. */ 3657 struct perf_event *itrs[2]; 3658 struct min_heap event_heap; 3659 struct perf_event **evt; 3660 int ret; 3661 3662 if (cpuctx) { 3663 event_heap = (struct min_heap){ 3664 .data = cpuctx->heap, 3665 .nr = 0, 3666 .size = cpuctx->heap_size, 3667 }; 3668 3669 lockdep_assert_held(&cpuctx->ctx.lock); 3670 3671 #ifdef CONFIG_CGROUP_PERF 3672 if (cpuctx->cgrp) 3673 css = &cpuctx->cgrp->css; 3674 #endif 3675 } else { 3676 event_heap = (struct min_heap){ 3677 .data = itrs, 3678 .nr = 0, 3679 .size = ARRAY_SIZE(itrs), 3680 }; 3681 /* Events not within a CPU context may be on any CPU. */ 3682 __heap_add(&event_heap, perf_event_groups_first(groups, -1, NULL)); 3683 } 3684 evt = event_heap.data; 3685 3686 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, NULL)); 3687 3688 #ifdef CONFIG_CGROUP_PERF 3689 for (; css; css = css->parent) 3690 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, css->cgroup)); 3691 #endif 3692 3693 min_heapify_all(&event_heap, &perf_min_heap); 3694 3695 while (event_heap.nr) { 3696 ret = func(*evt, data); 3697 if (ret) 3698 return ret; 3699 3700 *evt = perf_event_groups_next(*evt); 3701 if (*evt) 3702 min_heapify(&event_heap, 0, &perf_min_heap); 3703 else 3704 min_heap_pop(&event_heap, &perf_min_heap); 3705 } 3706 3707 return 0; 3708 } 3709 3710 static int merge_sched_in(struct perf_event *event, void *data) 3711 { 3712 struct perf_event_context *ctx = event->ctx; 3713 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 3714 int *can_add_hw = data; 3715 3716 if (event->state <= PERF_EVENT_STATE_OFF) 3717 return 0; 3718 3719 if (!event_filter_match(event)) 3720 return 0; 3721 3722 if (group_can_go_on(event, cpuctx, *can_add_hw)) { 3723 if (!group_sched_in(event, cpuctx, ctx)) 3724 list_add_tail(&event->active_list, get_event_list(event)); 3725 } 3726 3727 if (event->state == PERF_EVENT_STATE_INACTIVE) { 3728 if (event->attr.pinned) { 3729 perf_cgroup_event_disable(event, ctx); 3730 perf_event_set_state(event, PERF_EVENT_STATE_ERROR); 3731 } 3732 3733 *can_add_hw = 0; 3734 ctx->rotate_necessary = 1; 3735 perf_mux_hrtimer_restart(cpuctx); 3736 } 3737 3738 return 0; 3739 } 3740 3741 static void 3742 ctx_pinned_sched_in(struct perf_event_context *ctx, 3743 struct perf_cpu_context *cpuctx) 3744 { 3745 int can_add_hw = 1; 3746 3747 if (ctx != &cpuctx->ctx) 3748 cpuctx = NULL; 3749 3750 visit_groups_merge(cpuctx, &ctx->pinned_groups, 3751 smp_processor_id(), 3752 merge_sched_in, &can_add_hw); 3753 } 3754 3755 static void 3756 ctx_flexible_sched_in(struct perf_event_context *ctx, 3757 struct perf_cpu_context *cpuctx) 3758 { 3759 int can_add_hw = 1; 3760 3761 if (ctx != &cpuctx->ctx) 3762 cpuctx = NULL; 3763 3764 visit_groups_merge(cpuctx, &ctx->flexible_groups, 3765 smp_processor_id(), 3766 merge_sched_in, &can_add_hw); 3767 } 3768 3769 static void 3770 ctx_sched_in(struct perf_event_context *ctx, 3771 struct perf_cpu_context *cpuctx, 3772 enum event_type_t event_type, 3773 struct task_struct *task) 3774 { 3775 int is_active = ctx->is_active; 3776 u64 now; 3777 3778 lockdep_assert_held(&ctx->lock); 3779 3780 if (likely(!ctx->nr_events)) 3781 return; 3782 3783 ctx->is_active |= (event_type | EVENT_TIME); 3784 if (ctx->task) { 3785 if (!is_active) 3786 cpuctx->task_ctx = ctx; 3787 else 3788 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 3789 } 3790 3791 is_active ^= ctx->is_active; /* changed bits */ 3792 3793 if (is_active & EVENT_TIME) { 3794 /* start ctx time */ 3795 now = perf_clock(); 3796 ctx->timestamp = now; 3797 perf_cgroup_set_timestamp(task, ctx); 3798 } 3799 3800 /* 3801 * First go through the list and put on any pinned groups 3802 * in order to give them the best chance of going on. 3803 */ 3804 if (is_active & EVENT_PINNED) 3805 ctx_pinned_sched_in(ctx, cpuctx); 3806 3807 /* Then walk through the lower prio flexible groups */ 3808 if (is_active & EVENT_FLEXIBLE) 3809 ctx_flexible_sched_in(ctx, cpuctx); 3810 } 3811 3812 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, 3813 enum event_type_t event_type, 3814 struct task_struct *task) 3815 { 3816 struct perf_event_context *ctx = &cpuctx->ctx; 3817 3818 ctx_sched_in(ctx, cpuctx, event_type, task); 3819 } 3820 3821 static void perf_event_context_sched_in(struct perf_event_context *ctx, 3822 struct task_struct *task) 3823 { 3824 struct perf_cpu_context *cpuctx; 3825 struct pmu *pmu; 3826 3827 cpuctx = __get_cpu_context(ctx); 3828 3829 /* 3830 * HACK: for HETEROGENEOUS the task context might have switched to a 3831 * different PMU, force (re)set the context, 3832 */ 3833 pmu = ctx->pmu = cpuctx->ctx.pmu; 3834 3835 if (cpuctx->task_ctx == ctx) { 3836 if (cpuctx->sched_cb_usage) 3837 __perf_pmu_sched_task(cpuctx, true); 3838 return; 3839 } 3840 3841 perf_ctx_lock(cpuctx, ctx); 3842 /* 3843 * We must check ctx->nr_events while holding ctx->lock, such 3844 * that we serialize against perf_install_in_context(). 3845 */ 3846 if (!ctx->nr_events) 3847 goto unlock; 3848 3849 perf_pmu_disable(pmu); 3850 /* 3851 * We want to keep the following priority order: 3852 * cpu pinned (that don't need to move), task pinned, 3853 * cpu flexible, task flexible. 3854 * 3855 * However, if task's ctx is not carrying any pinned 3856 * events, no need to flip the cpuctx's events around. 3857 */ 3858 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree)) 3859 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); 3860 perf_event_sched_in(cpuctx, ctx, task); 3861 3862 if (cpuctx->sched_cb_usage && pmu->sched_task) 3863 pmu->sched_task(cpuctx->task_ctx, true); 3864 3865 perf_pmu_enable(pmu); 3866 3867 unlock: 3868 perf_ctx_unlock(cpuctx, ctx); 3869 } 3870 3871 /* 3872 * Called from scheduler to add the events of the current task 3873 * with interrupts disabled. 3874 * 3875 * We restore the event value and then enable it. 3876 * 3877 * This does not protect us against NMI, but enable() 3878 * sets the enabled bit in the control field of event _before_ 3879 * accessing the event control register. If a NMI hits, then it will 3880 * keep the event running. 3881 */ 3882 void __perf_event_task_sched_in(struct task_struct *prev, 3883 struct task_struct *task) 3884 { 3885 struct perf_event_context *ctx; 3886 int ctxn; 3887 3888 /* 3889 * If cgroup events exist on this CPU, then we need to check if we have 3890 * to switch in PMU state; cgroup event are system-wide mode only. 3891 * 3892 * Since cgroup events are CPU events, we must schedule these in before 3893 * we schedule in the task events. 3894 */ 3895 if (atomic_read(this_cpu_ptr(&perf_cgroup_events))) 3896 perf_cgroup_sched_in(prev, task); 3897 3898 for_each_task_context_nr(ctxn) { 3899 ctx = task->perf_event_ctxp[ctxn]; 3900 if (likely(!ctx)) 3901 continue; 3902 3903 perf_event_context_sched_in(ctx, task); 3904 } 3905 3906 if (atomic_read(&nr_switch_events)) 3907 perf_event_switch(task, prev, true); 3908 3909 if (__this_cpu_read(perf_sched_cb_usages)) 3910 perf_pmu_sched_task(prev, task, true); 3911 } 3912 3913 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count) 3914 { 3915 u64 frequency = event->attr.sample_freq; 3916 u64 sec = NSEC_PER_SEC; 3917 u64 divisor, dividend; 3918 3919 int count_fls, nsec_fls, frequency_fls, sec_fls; 3920 3921 count_fls = fls64(count); 3922 nsec_fls = fls64(nsec); 3923 frequency_fls = fls64(frequency); 3924 sec_fls = 30; 3925 3926 /* 3927 * We got @count in @nsec, with a target of sample_freq HZ 3928 * the target period becomes: 3929 * 3930 * @count * 10^9 3931 * period = ------------------- 3932 * @nsec * sample_freq 3933 * 3934 */ 3935 3936 /* 3937 * Reduce accuracy by one bit such that @a and @b converge 3938 * to a similar magnitude. 3939 */ 3940 #define REDUCE_FLS(a, b) \ 3941 do { \ 3942 if (a##_fls > b##_fls) { \ 3943 a >>= 1; \ 3944 a##_fls--; \ 3945 } else { \ 3946 b >>= 1; \ 3947 b##_fls--; \ 3948 } \ 3949 } while (0) 3950 3951 /* 3952 * Reduce accuracy until either term fits in a u64, then proceed with 3953 * the other, so that finally we can do a u64/u64 division. 3954 */ 3955 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) { 3956 REDUCE_FLS(nsec, frequency); 3957 REDUCE_FLS(sec, count); 3958 } 3959 3960 if (count_fls + sec_fls > 64) { 3961 divisor = nsec * frequency; 3962 3963 while (count_fls + sec_fls > 64) { 3964 REDUCE_FLS(count, sec); 3965 divisor >>= 1; 3966 } 3967 3968 dividend = count * sec; 3969 } else { 3970 dividend = count * sec; 3971 3972 while (nsec_fls + frequency_fls > 64) { 3973 REDUCE_FLS(nsec, frequency); 3974 dividend >>= 1; 3975 } 3976 3977 divisor = nsec * frequency; 3978 } 3979 3980 if (!divisor) 3981 return dividend; 3982 3983 return div64_u64(dividend, divisor); 3984 } 3985 3986 static DEFINE_PER_CPU(int, perf_throttled_count); 3987 static DEFINE_PER_CPU(u64, perf_throttled_seq); 3988 3989 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable) 3990 { 3991 struct hw_perf_event *hwc = &event->hw; 3992 s64 period, sample_period; 3993 s64 delta; 3994 3995 period = perf_calculate_period(event, nsec, count); 3996 3997 delta = (s64)(period - hwc->sample_period); 3998 delta = (delta + 7) / 8; /* low pass filter */ 3999 4000 sample_period = hwc->sample_period + delta; 4001 4002 if (!sample_period) 4003 sample_period = 1; 4004 4005 hwc->sample_period = sample_period; 4006 4007 if (local64_read(&hwc->period_left) > 8*sample_period) { 4008 if (disable) 4009 event->pmu->stop(event, PERF_EF_UPDATE); 4010 4011 local64_set(&hwc->period_left, 0); 4012 4013 if (disable) 4014 event->pmu->start(event, PERF_EF_RELOAD); 4015 } 4016 } 4017 4018 /* 4019 * combine freq adjustment with unthrottling to avoid two passes over the 4020 * events. At the same time, make sure, having freq events does not change 4021 * the rate of unthrottling as that would introduce bias. 4022 */ 4023 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx, 4024 int needs_unthr) 4025 { 4026 struct perf_event *event; 4027 struct hw_perf_event *hwc; 4028 u64 now, period = TICK_NSEC; 4029 s64 delta; 4030 4031 /* 4032 * only need to iterate over all events iff: 4033 * - context have events in frequency mode (needs freq adjust) 4034 * - there are events to unthrottle on this cpu 4035 */ 4036 if (!(ctx->nr_freq || needs_unthr)) 4037 return; 4038 4039 raw_spin_lock(&ctx->lock); 4040 perf_pmu_disable(ctx->pmu); 4041 4042 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 4043 if (event->state != PERF_EVENT_STATE_ACTIVE) 4044 continue; 4045 4046 if (!event_filter_match(event)) 4047 continue; 4048 4049 perf_pmu_disable(event->pmu); 4050 4051 hwc = &event->hw; 4052 4053 if (hwc->interrupts == MAX_INTERRUPTS) { 4054 hwc->interrupts = 0; 4055 perf_log_throttle(event, 1); 4056 event->pmu->start(event, 0); 4057 } 4058 4059 if (!event->attr.freq || !event->attr.sample_freq) 4060 goto next; 4061 4062 /* 4063 * stop the event and update event->count 4064 */ 4065 event->pmu->stop(event, PERF_EF_UPDATE); 4066 4067 now = local64_read(&event->count); 4068 delta = now - hwc->freq_count_stamp; 4069 hwc->freq_count_stamp = now; 4070 4071 /* 4072 * restart the event 4073 * reload only if value has changed 4074 * we have stopped the event so tell that 4075 * to perf_adjust_period() to avoid stopping it 4076 * twice. 4077 */ 4078 if (delta > 0) 4079 perf_adjust_period(event, period, delta, false); 4080 4081 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0); 4082 next: 4083 perf_pmu_enable(event->pmu); 4084 } 4085 4086 perf_pmu_enable(ctx->pmu); 4087 raw_spin_unlock(&ctx->lock); 4088 } 4089 4090 /* 4091 * Move @event to the tail of the @ctx's elegible events. 4092 */ 4093 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event) 4094 { 4095 /* 4096 * Rotate the first entry last of non-pinned groups. Rotation might be 4097 * disabled by the inheritance code. 4098 */ 4099 if (ctx->rotate_disable) 4100 return; 4101 4102 perf_event_groups_delete(&ctx->flexible_groups, event); 4103 perf_event_groups_insert(&ctx->flexible_groups, event); 4104 } 4105 4106 /* pick an event from the flexible_groups to rotate */ 4107 static inline struct perf_event * 4108 ctx_event_to_rotate(struct perf_event_context *ctx) 4109 { 4110 struct perf_event *event; 4111 4112 /* pick the first active flexible event */ 4113 event = list_first_entry_or_null(&ctx->flexible_active, 4114 struct perf_event, active_list); 4115 4116 /* if no active flexible event, pick the first event */ 4117 if (!event) { 4118 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree), 4119 typeof(*event), group_node); 4120 } 4121 4122 /* 4123 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in() 4124 * finds there are unschedulable events, it will set it again. 4125 */ 4126 ctx->rotate_necessary = 0; 4127 4128 return event; 4129 } 4130 4131 static bool perf_rotate_context(struct perf_cpu_context *cpuctx) 4132 { 4133 struct perf_event *cpu_event = NULL, *task_event = NULL; 4134 struct perf_event_context *task_ctx = NULL; 4135 int cpu_rotate, task_rotate; 4136 4137 /* 4138 * Since we run this from IRQ context, nobody can install new 4139 * events, thus the event count values are stable. 4140 */ 4141 4142 cpu_rotate = cpuctx->ctx.rotate_necessary; 4143 task_ctx = cpuctx->task_ctx; 4144 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0; 4145 4146 if (!(cpu_rotate || task_rotate)) 4147 return false; 4148 4149 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 4150 perf_pmu_disable(cpuctx->ctx.pmu); 4151 4152 if (task_rotate) 4153 task_event = ctx_event_to_rotate(task_ctx); 4154 if (cpu_rotate) 4155 cpu_event = ctx_event_to_rotate(&cpuctx->ctx); 4156 4157 /* 4158 * As per the order given at ctx_resched() first 'pop' task flexible 4159 * and then, if needed CPU flexible. 4160 */ 4161 if (task_event || (task_ctx && cpu_event)) 4162 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE); 4163 if (cpu_event) 4164 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); 4165 4166 if (task_event) 4167 rotate_ctx(task_ctx, task_event); 4168 if (cpu_event) 4169 rotate_ctx(&cpuctx->ctx, cpu_event); 4170 4171 perf_event_sched_in(cpuctx, task_ctx, current); 4172 4173 perf_pmu_enable(cpuctx->ctx.pmu); 4174 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 4175 4176 return true; 4177 } 4178 4179 void perf_event_task_tick(void) 4180 { 4181 struct list_head *head = this_cpu_ptr(&active_ctx_list); 4182 struct perf_event_context *ctx, *tmp; 4183 int throttled; 4184 4185 lockdep_assert_irqs_disabled(); 4186 4187 __this_cpu_inc(perf_throttled_seq); 4188 throttled = __this_cpu_xchg(perf_throttled_count, 0); 4189 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); 4190 4191 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list) 4192 perf_adjust_freq_unthr_context(ctx, throttled); 4193 } 4194 4195 static int event_enable_on_exec(struct perf_event *event, 4196 struct perf_event_context *ctx) 4197 { 4198 if (!event->attr.enable_on_exec) 4199 return 0; 4200 4201 event->attr.enable_on_exec = 0; 4202 if (event->state >= PERF_EVENT_STATE_INACTIVE) 4203 return 0; 4204 4205 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE); 4206 4207 return 1; 4208 } 4209 4210 /* 4211 * Enable all of a task's events that have been marked enable-on-exec. 4212 * This expects task == current. 4213 */ 4214 static void perf_event_enable_on_exec(int ctxn) 4215 { 4216 struct perf_event_context *ctx, *clone_ctx = NULL; 4217 enum event_type_t event_type = 0; 4218 struct perf_cpu_context *cpuctx; 4219 struct perf_event *event; 4220 unsigned long flags; 4221 int enabled = 0; 4222 4223 local_irq_save(flags); 4224 ctx = current->perf_event_ctxp[ctxn]; 4225 if (!ctx || !ctx->nr_events) 4226 goto out; 4227 4228 cpuctx = __get_cpu_context(ctx); 4229 perf_ctx_lock(cpuctx, ctx); 4230 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 4231 list_for_each_entry(event, &ctx->event_list, event_entry) { 4232 enabled |= event_enable_on_exec(event, ctx); 4233 event_type |= get_event_type(event); 4234 } 4235 4236 /* 4237 * Unclone and reschedule this context if we enabled any event. 4238 */ 4239 if (enabled) { 4240 clone_ctx = unclone_ctx(ctx); 4241 ctx_resched(cpuctx, ctx, event_type); 4242 } else { 4243 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current); 4244 } 4245 perf_ctx_unlock(cpuctx, ctx); 4246 4247 out: 4248 local_irq_restore(flags); 4249 4250 if (clone_ctx) 4251 put_ctx(clone_ctx); 4252 } 4253 4254 static void perf_remove_from_owner(struct perf_event *event); 4255 static void perf_event_exit_event(struct perf_event *event, 4256 struct perf_event_context *ctx); 4257 4258 /* 4259 * Removes all events from the current task that have been marked 4260 * remove-on-exec, and feeds their values back to parent events. 4261 */ 4262 static void perf_event_remove_on_exec(int ctxn) 4263 { 4264 struct perf_event_context *ctx, *clone_ctx = NULL; 4265 struct perf_event *event, *next; 4266 LIST_HEAD(free_list); 4267 unsigned long flags; 4268 bool modified = false; 4269 4270 ctx = perf_pin_task_context(current, ctxn); 4271 if (!ctx) 4272 return; 4273 4274 mutex_lock(&ctx->mutex); 4275 4276 if (WARN_ON_ONCE(ctx->task != current)) 4277 goto unlock; 4278 4279 list_for_each_entry_safe(event, next, &ctx->event_list, event_entry) { 4280 if (!event->attr.remove_on_exec) 4281 continue; 4282 4283 if (!is_kernel_event(event)) 4284 perf_remove_from_owner(event); 4285 4286 modified = true; 4287 4288 perf_event_exit_event(event, ctx); 4289 } 4290 4291 raw_spin_lock_irqsave(&ctx->lock, flags); 4292 if (modified) 4293 clone_ctx = unclone_ctx(ctx); 4294 --ctx->pin_count; 4295 raw_spin_unlock_irqrestore(&ctx->lock, flags); 4296 4297 unlock: 4298 mutex_unlock(&ctx->mutex); 4299 4300 put_ctx(ctx); 4301 if (clone_ctx) 4302 put_ctx(clone_ctx); 4303 } 4304 4305 struct perf_read_data { 4306 struct perf_event *event; 4307 bool group; 4308 int ret; 4309 }; 4310 4311 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu) 4312 { 4313 u16 local_pkg, event_pkg; 4314 4315 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) { 4316 int local_cpu = smp_processor_id(); 4317 4318 event_pkg = topology_physical_package_id(event_cpu); 4319 local_pkg = topology_physical_package_id(local_cpu); 4320 4321 if (event_pkg == local_pkg) 4322 return local_cpu; 4323 } 4324 4325 return event_cpu; 4326 } 4327 4328 /* 4329 * Cross CPU call to read the hardware event 4330 */ 4331 static void __perf_event_read(void *info) 4332 { 4333 struct perf_read_data *data = info; 4334 struct perf_event *sub, *event = data->event; 4335 struct perf_event_context *ctx = event->ctx; 4336 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 4337 struct pmu *pmu = event->pmu; 4338 4339 /* 4340 * If this is a task context, we need to check whether it is 4341 * the current task context of this cpu. If not it has been 4342 * scheduled out before the smp call arrived. In that case 4343 * event->count would have been updated to a recent sample 4344 * when the event was scheduled out. 4345 */ 4346 if (ctx->task && cpuctx->task_ctx != ctx) 4347 return; 4348 4349 raw_spin_lock(&ctx->lock); 4350 if (ctx->is_active & EVENT_TIME) { 4351 update_context_time(ctx); 4352 update_cgrp_time_from_event(event); 4353 } 4354 4355 perf_event_update_time(event); 4356 if (data->group) 4357 perf_event_update_sibling_time(event); 4358 4359 if (event->state != PERF_EVENT_STATE_ACTIVE) 4360 goto unlock; 4361 4362 if (!data->group) { 4363 pmu->read(event); 4364 data->ret = 0; 4365 goto unlock; 4366 } 4367 4368 pmu->start_txn(pmu, PERF_PMU_TXN_READ); 4369 4370 pmu->read(event); 4371 4372 for_each_sibling_event(sub, event) { 4373 if (sub->state == PERF_EVENT_STATE_ACTIVE) { 4374 /* 4375 * Use sibling's PMU rather than @event's since 4376 * sibling could be on different (eg: software) PMU. 4377 */ 4378 sub->pmu->read(sub); 4379 } 4380 } 4381 4382 data->ret = pmu->commit_txn(pmu); 4383 4384 unlock: 4385 raw_spin_unlock(&ctx->lock); 4386 } 4387 4388 static inline u64 perf_event_count(struct perf_event *event) 4389 { 4390 return local64_read(&event->count) + atomic64_read(&event->child_count); 4391 } 4392 4393 /* 4394 * NMI-safe method to read a local event, that is an event that 4395 * is: 4396 * - either for the current task, or for this CPU 4397 * - does not have inherit set, for inherited task events 4398 * will not be local and we cannot read them atomically 4399 * - must not have a pmu::count method 4400 */ 4401 int perf_event_read_local(struct perf_event *event, u64 *value, 4402 u64 *enabled, u64 *running) 4403 { 4404 unsigned long flags; 4405 int ret = 0; 4406 4407 /* 4408 * Disabling interrupts avoids all counter scheduling (context 4409 * switches, timer based rotation and IPIs). 4410 */ 4411 local_irq_save(flags); 4412 4413 /* 4414 * It must not be an event with inherit set, we cannot read 4415 * all child counters from atomic context. 4416 */ 4417 if (event->attr.inherit) { 4418 ret = -EOPNOTSUPP; 4419 goto out; 4420 } 4421 4422 /* If this is a per-task event, it must be for current */ 4423 if ((event->attach_state & PERF_ATTACH_TASK) && 4424 event->hw.target != current) { 4425 ret = -EINVAL; 4426 goto out; 4427 } 4428 4429 /* If this is a per-CPU event, it must be for this CPU */ 4430 if (!(event->attach_state & PERF_ATTACH_TASK) && 4431 event->cpu != smp_processor_id()) { 4432 ret = -EINVAL; 4433 goto out; 4434 } 4435 4436 /* If this is a pinned event it must be running on this CPU */ 4437 if (event->attr.pinned && event->oncpu != smp_processor_id()) { 4438 ret = -EBUSY; 4439 goto out; 4440 } 4441 4442 /* 4443 * If the event is currently on this CPU, its either a per-task event, 4444 * or local to this CPU. Furthermore it means its ACTIVE (otherwise 4445 * oncpu == -1). 4446 */ 4447 if (event->oncpu == smp_processor_id()) 4448 event->pmu->read(event); 4449 4450 *value = local64_read(&event->count); 4451 if (enabled || running) { 4452 u64 now = event->shadow_ctx_time + perf_clock(); 4453 u64 __enabled, __running; 4454 4455 __perf_update_times(event, now, &__enabled, &__running); 4456 if (enabled) 4457 *enabled = __enabled; 4458 if (running) 4459 *running = __running; 4460 } 4461 out: 4462 local_irq_restore(flags); 4463 4464 return ret; 4465 } 4466 4467 static int perf_event_read(struct perf_event *event, bool group) 4468 { 4469 enum perf_event_state state = READ_ONCE(event->state); 4470 int event_cpu, ret = 0; 4471 4472 /* 4473 * If event is enabled and currently active on a CPU, update the 4474 * value in the event structure: 4475 */ 4476 again: 4477 if (state == PERF_EVENT_STATE_ACTIVE) { 4478 struct perf_read_data data; 4479 4480 /* 4481 * Orders the ->state and ->oncpu loads such that if we see 4482 * ACTIVE we must also see the right ->oncpu. 4483 * 4484 * Matches the smp_wmb() from event_sched_in(). 4485 */ 4486 smp_rmb(); 4487 4488 event_cpu = READ_ONCE(event->oncpu); 4489 if ((unsigned)event_cpu >= nr_cpu_ids) 4490 return 0; 4491 4492 data = (struct perf_read_data){ 4493 .event = event, 4494 .group = group, 4495 .ret = 0, 4496 }; 4497 4498 preempt_disable(); 4499 event_cpu = __perf_event_read_cpu(event, event_cpu); 4500 4501 /* 4502 * Purposely ignore the smp_call_function_single() return 4503 * value. 4504 * 4505 * If event_cpu isn't a valid CPU it means the event got 4506 * scheduled out and that will have updated the event count. 4507 * 4508 * Therefore, either way, we'll have an up-to-date event count 4509 * after this. 4510 */ 4511 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1); 4512 preempt_enable(); 4513 ret = data.ret; 4514 4515 } else if (state == PERF_EVENT_STATE_INACTIVE) { 4516 struct perf_event_context *ctx = event->ctx; 4517 unsigned long flags; 4518 4519 raw_spin_lock_irqsave(&ctx->lock, flags); 4520 state = event->state; 4521 if (state != PERF_EVENT_STATE_INACTIVE) { 4522 raw_spin_unlock_irqrestore(&ctx->lock, flags); 4523 goto again; 4524 } 4525 4526 /* 4527 * May read while context is not active (e.g., thread is 4528 * blocked), in that case we cannot update context time 4529 */ 4530 if (ctx->is_active & EVENT_TIME) { 4531 update_context_time(ctx); 4532 update_cgrp_time_from_event(event); 4533 } 4534 4535 perf_event_update_time(event); 4536 if (group) 4537 perf_event_update_sibling_time(event); 4538 raw_spin_unlock_irqrestore(&ctx->lock, flags); 4539 } 4540 4541 return ret; 4542 } 4543 4544 /* 4545 * Initialize the perf_event context in a task_struct: 4546 */ 4547 static void __perf_event_init_context(struct perf_event_context *ctx) 4548 { 4549 raw_spin_lock_init(&ctx->lock); 4550 mutex_init(&ctx->mutex); 4551 INIT_LIST_HEAD(&ctx->active_ctx_list); 4552 perf_event_groups_init(&ctx->pinned_groups); 4553 perf_event_groups_init(&ctx->flexible_groups); 4554 INIT_LIST_HEAD(&ctx->event_list); 4555 INIT_LIST_HEAD(&ctx->pinned_active); 4556 INIT_LIST_HEAD(&ctx->flexible_active); 4557 refcount_set(&ctx->refcount, 1); 4558 } 4559 4560 static struct perf_event_context * 4561 alloc_perf_context(struct pmu *pmu, struct task_struct *task) 4562 { 4563 struct perf_event_context *ctx; 4564 4565 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL); 4566 if (!ctx) 4567 return NULL; 4568 4569 __perf_event_init_context(ctx); 4570 if (task) 4571 ctx->task = get_task_struct(task); 4572 ctx->pmu = pmu; 4573 4574 return ctx; 4575 } 4576 4577 static struct task_struct * 4578 find_lively_task_by_vpid(pid_t vpid) 4579 { 4580 struct task_struct *task; 4581 4582 rcu_read_lock(); 4583 if (!vpid) 4584 task = current; 4585 else 4586 task = find_task_by_vpid(vpid); 4587 if (task) 4588 get_task_struct(task); 4589 rcu_read_unlock(); 4590 4591 if (!task) 4592 return ERR_PTR(-ESRCH); 4593 4594 return task; 4595 } 4596 4597 /* 4598 * Returns a matching context with refcount and pincount. 4599 */ 4600 static struct perf_event_context * 4601 find_get_context(struct pmu *pmu, struct task_struct *task, 4602 struct perf_event *event) 4603 { 4604 struct perf_event_context *ctx, *clone_ctx = NULL; 4605 struct perf_cpu_context *cpuctx; 4606 void *task_ctx_data = NULL; 4607 unsigned long flags; 4608 int ctxn, err; 4609 int cpu = event->cpu; 4610 4611 if (!task) { 4612 /* Must be root to operate on a CPU event: */ 4613 err = perf_allow_cpu(&event->attr); 4614 if (err) 4615 return ERR_PTR(err); 4616 4617 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 4618 ctx = &cpuctx->ctx; 4619 get_ctx(ctx); 4620 raw_spin_lock_irqsave(&ctx->lock, flags); 4621 ++ctx->pin_count; 4622 raw_spin_unlock_irqrestore(&ctx->lock, flags); 4623 4624 return ctx; 4625 } 4626 4627 err = -EINVAL; 4628 ctxn = pmu->task_ctx_nr; 4629 if (ctxn < 0) 4630 goto errout; 4631 4632 if (event->attach_state & PERF_ATTACH_TASK_DATA) { 4633 task_ctx_data = alloc_task_ctx_data(pmu); 4634 if (!task_ctx_data) { 4635 err = -ENOMEM; 4636 goto errout; 4637 } 4638 } 4639 4640 retry: 4641 ctx = perf_lock_task_context(task, ctxn, &flags); 4642 if (ctx) { 4643 clone_ctx = unclone_ctx(ctx); 4644 ++ctx->pin_count; 4645 4646 if (task_ctx_data && !ctx->task_ctx_data) { 4647 ctx->task_ctx_data = task_ctx_data; 4648 task_ctx_data = NULL; 4649 } 4650 raw_spin_unlock_irqrestore(&ctx->lock, flags); 4651 4652 if (clone_ctx) 4653 put_ctx(clone_ctx); 4654 } else { 4655 ctx = alloc_perf_context(pmu, task); 4656 err = -ENOMEM; 4657 if (!ctx) 4658 goto errout; 4659 4660 if (task_ctx_data) { 4661 ctx->task_ctx_data = task_ctx_data; 4662 task_ctx_data = NULL; 4663 } 4664 4665 err = 0; 4666 mutex_lock(&task->perf_event_mutex); 4667 /* 4668 * If it has already passed perf_event_exit_task(). 4669 * we must see PF_EXITING, it takes this mutex too. 4670 */ 4671 if (task->flags & PF_EXITING) 4672 err = -ESRCH; 4673 else if (task->perf_event_ctxp[ctxn]) 4674 err = -EAGAIN; 4675 else { 4676 get_ctx(ctx); 4677 ++ctx->pin_count; 4678 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx); 4679 } 4680 mutex_unlock(&task->perf_event_mutex); 4681 4682 if (unlikely(err)) { 4683 put_ctx(ctx); 4684 4685 if (err == -EAGAIN) 4686 goto retry; 4687 goto errout; 4688 } 4689 } 4690 4691 free_task_ctx_data(pmu, task_ctx_data); 4692 return ctx; 4693 4694 errout: 4695 free_task_ctx_data(pmu, task_ctx_data); 4696 return ERR_PTR(err); 4697 } 4698 4699 static void perf_event_free_filter(struct perf_event *event); 4700 4701 static void free_event_rcu(struct rcu_head *head) 4702 { 4703 struct perf_event *event; 4704 4705 event = container_of(head, struct perf_event, rcu_head); 4706 if (event->ns) 4707 put_pid_ns(event->ns); 4708 perf_event_free_filter(event); 4709 kmem_cache_free(perf_event_cache, event); 4710 } 4711 4712 static void ring_buffer_attach(struct perf_event *event, 4713 struct perf_buffer *rb); 4714 4715 static void detach_sb_event(struct perf_event *event) 4716 { 4717 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu); 4718 4719 raw_spin_lock(&pel->lock); 4720 list_del_rcu(&event->sb_list); 4721 raw_spin_unlock(&pel->lock); 4722 } 4723 4724 static bool is_sb_event(struct perf_event *event) 4725 { 4726 struct perf_event_attr *attr = &event->attr; 4727 4728 if (event->parent) 4729 return false; 4730 4731 if (event->attach_state & PERF_ATTACH_TASK) 4732 return false; 4733 4734 if (attr->mmap || attr->mmap_data || attr->mmap2 || 4735 attr->comm || attr->comm_exec || 4736 attr->task || attr->ksymbol || 4737 attr->context_switch || attr->text_poke || 4738 attr->bpf_event) 4739 return true; 4740 return false; 4741 } 4742 4743 static void unaccount_pmu_sb_event(struct perf_event *event) 4744 { 4745 if (is_sb_event(event)) 4746 detach_sb_event(event); 4747 } 4748 4749 static void unaccount_event_cpu(struct perf_event *event, int cpu) 4750 { 4751 if (event->parent) 4752 return; 4753 4754 if (is_cgroup_event(event)) 4755 atomic_dec(&per_cpu(perf_cgroup_events, cpu)); 4756 } 4757 4758 #ifdef CONFIG_NO_HZ_FULL 4759 static DEFINE_SPINLOCK(nr_freq_lock); 4760 #endif 4761 4762 static void unaccount_freq_event_nohz(void) 4763 { 4764 #ifdef CONFIG_NO_HZ_FULL 4765 spin_lock(&nr_freq_lock); 4766 if (atomic_dec_and_test(&nr_freq_events)) 4767 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS); 4768 spin_unlock(&nr_freq_lock); 4769 #endif 4770 } 4771 4772 static void unaccount_freq_event(void) 4773 { 4774 if (tick_nohz_full_enabled()) 4775 unaccount_freq_event_nohz(); 4776 else 4777 atomic_dec(&nr_freq_events); 4778 } 4779 4780 static void unaccount_event(struct perf_event *event) 4781 { 4782 bool dec = false; 4783 4784 if (event->parent) 4785 return; 4786 4787 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB)) 4788 dec = true; 4789 if (event->attr.mmap || event->attr.mmap_data) 4790 atomic_dec(&nr_mmap_events); 4791 if (event->attr.build_id) 4792 atomic_dec(&nr_build_id_events); 4793 if (event->attr.comm) 4794 atomic_dec(&nr_comm_events); 4795 if (event->attr.namespaces) 4796 atomic_dec(&nr_namespaces_events); 4797 if (event->attr.cgroup) 4798 atomic_dec(&nr_cgroup_events); 4799 if (event->attr.task) 4800 atomic_dec(&nr_task_events); 4801 if (event->attr.freq) 4802 unaccount_freq_event(); 4803 if (event->attr.context_switch) { 4804 dec = true; 4805 atomic_dec(&nr_switch_events); 4806 } 4807 if (is_cgroup_event(event)) 4808 dec = true; 4809 if (has_branch_stack(event)) 4810 dec = true; 4811 if (event->attr.ksymbol) 4812 atomic_dec(&nr_ksymbol_events); 4813 if (event->attr.bpf_event) 4814 atomic_dec(&nr_bpf_events); 4815 if (event->attr.text_poke) 4816 atomic_dec(&nr_text_poke_events); 4817 4818 if (dec) { 4819 if (!atomic_add_unless(&perf_sched_count, -1, 1)) 4820 schedule_delayed_work(&perf_sched_work, HZ); 4821 } 4822 4823 unaccount_event_cpu(event, event->cpu); 4824 4825 unaccount_pmu_sb_event(event); 4826 } 4827 4828 static void perf_sched_delayed(struct work_struct *work) 4829 { 4830 mutex_lock(&perf_sched_mutex); 4831 if (atomic_dec_and_test(&perf_sched_count)) 4832 static_branch_disable(&perf_sched_events); 4833 mutex_unlock(&perf_sched_mutex); 4834 } 4835 4836 /* 4837 * The following implement mutual exclusion of events on "exclusive" pmus 4838 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled 4839 * at a time, so we disallow creating events that might conflict, namely: 4840 * 4841 * 1) cpu-wide events in the presence of per-task events, 4842 * 2) per-task events in the presence of cpu-wide events, 4843 * 3) two matching events on the same context. 4844 * 4845 * The former two cases are handled in the allocation path (perf_event_alloc(), 4846 * _free_event()), the latter -- before the first perf_install_in_context(). 4847 */ 4848 static int exclusive_event_init(struct perf_event *event) 4849 { 4850 struct pmu *pmu = event->pmu; 4851 4852 if (!is_exclusive_pmu(pmu)) 4853 return 0; 4854 4855 /* 4856 * Prevent co-existence of per-task and cpu-wide events on the 4857 * same exclusive pmu. 4858 * 4859 * Negative pmu::exclusive_cnt means there are cpu-wide 4860 * events on this "exclusive" pmu, positive means there are 4861 * per-task events. 4862 * 4863 * Since this is called in perf_event_alloc() path, event::ctx 4864 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK 4865 * to mean "per-task event", because unlike other attach states it 4866 * never gets cleared. 4867 */ 4868 if (event->attach_state & PERF_ATTACH_TASK) { 4869 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt)) 4870 return -EBUSY; 4871 } else { 4872 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt)) 4873 return -EBUSY; 4874 } 4875 4876 return 0; 4877 } 4878 4879 static void exclusive_event_destroy(struct perf_event *event) 4880 { 4881 struct pmu *pmu = event->pmu; 4882 4883 if (!is_exclusive_pmu(pmu)) 4884 return; 4885 4886 /* see comment in exclusive_event_init() */ 4887 if (event->attach_state & PERF_ATTACH_TASK) 4888 atomic_dec(&pmu->exclusive_cnt); 4889 else 4890 atomic_inc(&pmu->exclusive_cnt); 4891 } 4892 4893 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2) 4894 { 4895 if ((e1->pmu == e2->pmu) && 4896 (e1->cpu == e2->cpu || 4897 e1->cpu == -1 || 4898 e2->cpu == -1)) 4899 return true; 4900 return false; 4901 } 4902 4903 static bool exclusive_event_installable(struct perf_event *event, 4904 struct perf_event_context *ctx) 4905 { 4906 struct perf_event *iter_event; 4907 struct pmu *pmu = event->pmu; 4908 4909 lockdep_assert_held(&ctx->mutex); 4910 4911 if (!is_exclusive_pmu(pmu)) 4912 return true; 4913 4914 list_for_each_entry(iter_event, &ctx->event_list, event_entry) { 4915 if (exclusive_event_match(iter_event, event)) 4916 return false; 4917 } 4918 4919 return true; 4920 } 4921 4922 static void perf_addr_filters_splice(struct perf_event *event, 4923 struct list_head *head); 4924 4925 static void _free_event(struct perf_event *event) 4926 { 4927 irq_work_sync(&event->pending); 4928 4929 unaccount_event(event); 4930 4931 security_perf_event_free(event); 4932 4933 if (event->rb) { 4934 /* 4935 * Can happen when we close an event with re-directed output. 4936 * 4937 * Since we have a 0 refcount, perf_mmap_close() will skip 4938 * over us; possibly making our ring_buffer_put() the last. 4939 */ 4940 mutex_lock(&event->mmap_mutex); 4941 ring_buffer_attach(event, NULL); 4942 mutex_unlock(&event->mmap_mutex); 4943 } 4944 4945 if (is_cgroup_event(event)) 4946 perf_detach_cgroup(event); 4947 4948 if (!event->parent) { 4949 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) 4950 put_callchain_buffers(); 4951 } 4952 4953 perf_event_free_bpf_prog(event); 4954 perf_addr_filters_splice(event, NULL); 4955 kfree(event->addr_filter_ranges); 4956 4957 if (event->destroy) 4958 event->destroy(event); 4959 4960 /* 4961 * Must be after ->destroy(), due to uprobe_perf_close() using 4962 * hw.target. 4963 */ 4964 if (event->hw.target) 4965 put_task_struct(event->hw.target); 4966 4967 /* 4968 * perf_event_free_task() relies on put_ctx() being 'last', in particular 4969 * all task references must be cleaned up. 4970 */ 4971 if (event->ctx) 4972 put_ctx(event->ctx); 4973 4974 exclusive_event_destroy(event); 4975 module_put(event->pmu->module); 4976 4977 call_rcu(&event->rcu_head, free_event_rcu); 4978 } 4979 4980 /* 4981 * Used to free events which have a known refcount of 1, such as in error paths 4982 * where the event isn't exposed yet and inherited events. 4983 */ 4984 static void free_event(struct perf_event *event) 4985 { 4986 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1, 4987 "unexpected event refcount: %ld; ptr=%p\n", 4988 atomic_long_read(&event->refcount), event)) { 4989 /* leak to avoid use-after-free */ 4990 return; 4991 } 4992 4993 _free_event(event); 4994 } 4995 4996 /* 4997 * Remove user event from the owner task. 4998 */ 4999 static void perf_remove_from_owner(struct perf_event *event) 5000 { 5001 struct task_struct *owner; 5002 5003 rcu_read_lock(); 5004 /* 5005 * Matches the smp_store_release() in perf_event_exit_task(). If we 5006 * observe !owner it means the list deletion is complete and we can 5007 * indeed free this event, otherwise we need to serialize on 5008 * owner->perf_event_mutex. 5009 */ 5010 owner = READ_ONCE(event->owner); 5011 if (owner) { 5012 /* 5013 * Since delayed_put_task_struct() also drops the last 5014 * task reference we can safely take a new reference 5015 * while holding the rcu_read_lock(). 5016 */ 5017 get_task_struct(owner); 5018 } 5019 rcu_read_unlock(); 5020 5021 if (owner) { 5022 /* 5023 * If we're here through perf_event_exit_task() we're already 5024 * holding ctx->mutex which would be an inversion wrt. the 5025 * normal lock order. 5026 * 5027 * However we can safely take this lock because its the child 5028 * ctx->mutex. 5029 */ 5030 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING); 5031 5032 /* 5033 * We have to re-check the event->owner field, if it is cleared 5034 * we raced with perf_event_exit_task(), acquiring the mutex 5035 * ensured they're done, and we can proceed with freeing the 5036 * event. 5037 */ 5038 if (event->owner) { 5039 list_del_init(&event->owner_entry); 5040 smp_store_release(&event->owner, NULL); 5041 } 5042 mutex_unlock(&owner->perf_event_mutex); 5043 put_task_struct(owner); 5044 } 5045 } 5046 5047 static void put_event(struct perf_event *event) 5048 { 5049 if (!atomic_long_dec_and_test(&event->refcount)) 5050 return; 5051 5052 _free_event(event); 5053 } 5054 5055 /* 5056 * Kill an event dead; while event:refcount will preserve the event 5057 * object, it will not preserve its functionality. Once the last 'user' 5058 * gives up the object, we'll destroy the thing. 5059 */ 5060 int perf_event_release_kernel(struct perf_event *event) 5061 { 5062 struct perf_event_context *ctx = event->ctx; 5063 struct perf_event *child, *tmp; 5064 LIST_HEAD(free_list); 5065 5066 /* 5067 * If we got here through err_file: fput(event_file); we will not have 5068 * attached to a context yet. 5069 */ 5070 if (!ctx) { 5071 WARN_ON_ONCE(event->attach_state & 5072 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP)); 5073 goto no_ctx; 5074 } 5075 5076 if (!is_kernel_event(event)) 5077 perf_remove_from_owner(event); 5078 5079 ctx = perf_event_ctx_lock(event); 5080 WARN_ON_ONCE(ctx->parent_ctx); 5081 perf_remove_from_context(event, DETACH_GROUP); 5082 5083 raw_spin_lock_irq(&ctx->lock); 5084 /* 5085 * Mark this event as STATE_DEAD, there is no external reference to it 5086 * anymore. 5087 * 5088 * Anybody acquiring event->child_mutex after the below loop _must_ 5089 * also see this, most importantly inherit_event() which will avoid 5090 * placing more children on the list. 5091 * 5092 * Thus this guarantees that we will in fact observe and kill _ALL_ 5093 * child events. 5094 */ 5095 event->state = PERF_EVENT_STATE_DEAD; 5096 raw_spin_unlock_irq(&ctx->lock); 5097 5098 perf_event_ctx_unlock(event, ctx); 5099 5100 again: 5101 mutex_lock(&event->child_mutex); 5102 list_for_each_entry(child, &event->child_list, child_list) { 5103 5104 /* 5105 * Cannot change, child events are not migrated, see the 5106 * comment with perf_event_ctx_lock_nested(). 5107 */ 5108 ctx = READ_ONCE(child->ctx); 5109 /* 5110 * Since child_mutex nests inside ctx::mutex, we must jump 5111 * through hoops. We start by grabbing a reference on the ctx. 5112 * 5113 * Since the event cannot get freed while we hold the 5114 * child_mutex, the context must also exist and have a !0 5115 * reference count. 5116 */ 5117 get_ctx(ctx); 5118 5119 /* 5120 * Now that we have a ctx ref, we can drop child_mutex, and 5121 * acquire ctx::mutex without fear of it going away. Then we 5122 * can re-acquire child_mutex. 5123 */ 5124 mutex_unlock(&event->child_mutex); 5125 mutex_lock(&ctx->mutex); 5126 mutex_lock(&event->child_mutex); 5127 5128 /* 5129 * Now that we hold ctx::mutex and child_mutex, revalidate our 5130 * state, if child is still the first entry, it didn't get freed 5131 * and we can continue doing so. 5132 */ 5133 tmp = list_first_entry_or_null(&event->child_list, 5134 struct perf_event, child_list); 5135 if (tmp == child) { 5136 perf_remove_from_context(child, DETACH_GROUP); 5137 list_move(&child->child_list, &free_list); 5138 /* 5139 * This matches the refcount bump in inherit_event(); 5140 * this can't be the last reference. 5141 */ 5142 put_event(event); 5143 } 5144 5145 mutex_unlock(&event->child_mutex); 5146 mutex_unlock(&ctx->mutex); 5147 put_ctx(ctx); 5148 goto again; 5149 } 5150 mutex_unlock(&event->child_mutex); 5151 5152 list_for_each_entry_safe(child, tmp, &free_list, child_list) { 5153 void *var = &child->ctx->refcount; 5154 5155 list_del(&child->child_list); 5156 free_event(child); 5157 5158 /* 5159 * Wake any perf_event_free_task() waiting for this event to be 5160 * freed. 5161 */ 5162 smp_mb(); /* pairs with wait_var_event() */ 5163 wake_up_var(var); 5164 } 5165 5166 no_ctx: 5167 put_event(event); /* Must be the 'last' reference */ 5168 return 0; 5169 } 5170 EXPORT_SYMBOL_GPL(perf_event_release_kernel); 5171 5172 /* 5173 * Called when the last reference to the file is gone. 5174 */ 5175 static int perf_release(struct inode *inode, struct file *file) 5176 { 5177 perf_event_release_kernel(file->private_data); 5178 return 0; 5179 } 5180 5181 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) 5182 { 5183 struct perf_event *child; 5184 u64 total = 0; 5185 5186 *enabled = 0; 5187 *running = 0; 5188 5189 mutex_lock(&event->child_mutex); 5190 5191 (void)perf_event_read(event, false); 5192 total += perf_event_count(event); 5193 5194 *enabled += event->total_time_enabled + 5195 atomic64_read(&event->child_total_time_enabled); 5196 *running += event->total_time_running + 5197 atomic64_read(&event->child_total_time_running); 5198 5199 list_for_each_entry(child, &event->child_list, child_list) { 5200 (void)perf_event_read(child, false); 5201 total += perf_event_count(child); 5202 *enabled += child->total_time_enabled; 5203 *running += child->total_time_running; 5204 } 5205 mutex_unlock(&event->child_mutex); 5206 5207 return total; 5208 } 5209 5210 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) 5211 { 5212 struct perf_event_context *ctx; 5213 u64 count; 5214 5215 ctx = perf_event_ctx_lock(event); 5216 count = __perf_event_read_value(event, enabled, running); 5217 perf_event_ctx_unlock(event, ctx); 5218 5219 return count; 5220 } 5221 EXPORT_SYMBOL_GPL(perf_event_read_value); 5222 5223 static int __perf_read_group_add(struct perf_event *leader, 5224 u64 read_format, u64 *values) 5225 { 5226 struct perf_event_context *ctx = leader->ctx; 5227 struct perf_event *sub; 5228 unsigned long flags; 5229 int n = 1; /* skip @nr */ 5230 int ret; 5231 5232 ret = perf_event_read(leader, true); 5233 if (ret) 5234 return ret; 5235 5236 raw_spin_lock_irqsave(&ctx->lock, flags); 5237 5238 /* 5239 * Since we co-schedule groups, {enabled,running} times of siblings 5240 * will be identical to those of the leader, so we only publish one 5241 * set. 5242 */ 5243 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { 5244 values[n++] += leader->total_time_enabled + 5245 atomic64_read(&leader->child_total_time_enabled); 5246 } 5247 5248 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { 5249 values[n++] += leader->total_time_running + 5250 atomic64_read(&leader->child_total_time_running); 5251 } 5252 5253 /* 5254 * Write {count,id} tuples for every sibling. 5255 */ 5256 values[n++] += perf_event_count(leader); 5257 if (read_format & PERF_FORMAT_ID) 5258 values[n++] = primary_event_id(leader); 5259 5260 for_each_sibling_event(sub, leader) { 5261 values[n++] += perf_event_count(sub); 5262 if (read_format & PERF_FORMAT_ID) 5263 values[n++] = primary_event_id(sub); 5264 } 5265 5266 raw_spin_unlock_irqrestore(&ctx->lock, flags); 5267 return 0; 5268 } 5269 5270 static int perf_read_group(struct perf_event *event, 5271 u64 read_format, char __user *buf) 5272 { 5273 struct perf_event *leader = event->group_leader, *child; 5274 struct perf_event_context *ctx = leader->ctx; 5275 int ret; 5276 u64 *values; 5277 5278 lockdep_assert_held(&ctx->mutex); 5279 5280 values = kzalloc(event->read_size, GFP_KERNEL); 5281 if (!values) 5282 return -ENOMEM; 5283 5284 values[0] = 1 + leader->nr_siblings; 5285 5286 /* 5287 * By locking the child_mutex of the leader we effectively 5288 * lock the child list of all siblings.. XXX explain how. 5289 */ 5290 mutex_lock(&leader->child_mutex); 5291 5292 ret = __perf_read_group_add(leader, read_format, values); 5293 if (ret) 5294 goto unlock; 5295 5296 list_for_each_entry(child, &leader->child_list, child_list) { 5297 ret = __perf_read_group_add(child, read_format, values); 5298 if (ret) 5299 goto unlock; 5300 } 5301 5302 mutex_unlock(&leader->child_mutex); 5303 5304 ret = event->read_size; 5305 if (copy_to_user(buf, values, event->read_size)) 5306 ret = -EFAULT; 5307 goto out; 5308 5309 unlock: 5310 mutex_unlock(&leader->child_mutex); 5311 out: 5312 kfree(values); 5313 return ret; 5314 } 5315 5316 static int perf_read_one(struct perf_event *event, 5317 u64 read_format, char __user *buf) 5318 { 5319 u64 enabled, running; 5320 u64 values[4]; 5321 int n = 0; 5322 5323 values[n++] = __perf_event_read_value(event, &enabled, &running); 5324 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 5325 values[n++] = enabled; 5326 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 5327 values[n++] = running; 5328 if (read_format & PERF_FORMAT_ID) 5329 values[n++] = primary_event_id(event); 5330 5331 if (copy_to_user(buf, values, n * sizeof(u64))) 5332 return -EFAULT; 5333 5334 return n * sizeof(u64); 5335 } 5336 5337 static bool is_event_hup(struct perf_event *event) 5338 { 5339 bool no_children; 5340 5341 if (event->state > PERF_EVENT_STATE_EXIT) 5342 return false; 5343 5344 mutex_lock(&event->child_mutex); 5345 no_children = list_empty(&event->child_list); 5346 mutex_unlock(&event->child_mutex); 5347 return no_children; 5348 } 5349 5350 /* 5351 * Read the performance event - simple non blocking version for now 5352 */ 5353 static ssize_t 5354 __perf_read(struct perf_event *event, char __user *buf, size_t count) 5355 { 5356 u64 read_format = event->attr.read_format; 5357 int ret; 5358 5359 /* 5360 * Return end-of-file for a read on an event that is in 5361 * error state (i.e. because it was pinned but it couldn't be 5362 * scheduled on to the CPU at some point). 5363 */ 5364 if (event->state == PERF_EVENT_STATE_ERROR) 5365 return 0; 5366 5367 if (count < event->read_size) 5368 return -ENOSPC; 5369 5370 WARN_ON_ONCE(event->ctx->parent_ctx); 5371 if (read_format & PERF_FORMAT_GROUP) 5372 ret = perf_read_group(event, read_format, buf); 5373 else 5374 ret = perf_read_one(event, read_format, buf); 5375 5376 return ret; 5377 } 5378 5379 static ssize_t 5380 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 5381 { 5382 struct perf_event *event = file->private_data; 5383 struct perf_event_context *ctx; 5384 int ret; 5385 5386 ret = security_perf_event_read(event); 5387 if (ret) 5388 return ret; 5389 5390 ctx = perf_event_ctx_lock(event); 5391 ret = __perf_read(event, buf, count); 5392 perf_event_ctx_unlock(event, ctx); 5393 5394 return ret; 5395 } 5396 5397 static __poll_t perf_poll(struct file *file, poll_table *wait) 5398 { 5399 struct perf_event *event = file->private_data; 5400 struct perf_buffer *rb; 5401 __poll_t events = EPOLLHUP; 5402 5403 poll_wait(file, &event->waitq, wait); 5404 5405 if (is_event_hup(event)) 5406 return events; 5407 5408 /* 5409 * Pin the event->rb by taking event->mmap_mutex; otherwise 5410 * perf_event_set_output() can swizzle our rb and make us miss wakeups. 5411 */ 5412 mutex_lock(&event->mmap_mutex); 5413 rb = event->rb; 5414 if (rb) 5415 events = atomic_xchg(&rb->poll, 0); 5416 mutex_unlock(&event->mmap_mutex); 5417 return events; 5418 } 5419 5420 static void _perf_event_reset(struct perf_event *event) 5421 { 5422 (void)perf_event_read(event, false); 5423 local64_set(&event->count, 0); 5424 perf_event_update_userpage(event); 5425 } 5426 5427 /* Assume it's not an event with inherit set. */ 5428 u64 perf_event_pause(struct perf_event *event, bool reset) 5429 { 5430 struct perf_event_context *ctx; 5431 u64 count; 5432 5433 ctx = perf_event_ctx_lock(event); 5434 WARN_ON_ONCE(event->attr.inherit); 5435 _perf_event_disable(event); 5436 count = local64_read(&event->count); 5437 if (reset) 5438 local64_set(&event->count, 0); 5439 perf_event_ctx_unlock(event, ctx); 5440 5441 return count; 5442 } 5443 EXPORT_SYMBOL_GPL(perf_event_pause); 5444 5445 /* 5446 * Holding the top-level event's child_mutex means that any 5447 * descendant process that has inherited this event will block 5448 * in perf_event_exit_event() if it goes to exit, thus satisfying the 5449 * task existence requirements of perf_event_enable/disable. 5450 */ 5451 static void perf_event_for_each_child(struct perf_event *event, 5452 void (*func)(struct perf_event *)) 5453 { 5454 struct perf_event *child; 5455 5456 WARN_ON_ONCE(event->ctx->parent_ctx); 5457 5458 mutex_lock(&event->child_mutex); 5459 func(event); 5460 list_for_each_entry(child, &event->child_list, child_list) 5461 func(child); 5462 mutex_unlock(&event->child_mutex); 5463 } 5464 5465 static void perf_event_for_each(struct perf_event *event, 5466 void (*func)(struct perf_event *)) 5467 { 5468 struct perf_event_context *ctx = event->ctx; 5469 struct perf_event *sibling; 5470 5471 lockdep_assert_held(&ctx->mutex); 5472 5473 event = event->group_leader; 5474 5475 perf_event_for_each_child(event, func); 5476 for_each_sibling_event(sibling, event) 5477 perf_event_for_each_child(sibling, func); 5478 } 5479 5480 static void __perf_event_period(struct perf_event *event, 5481 struct perf_cpu_context *cpuctx, 5482 struct perf_event_context *ctx, 5483 void *info) 5484 { 5485 u64 value = *((u64 *)info); 5486 bool active; 5487 5488 if (event->attr.freq) { 5489 event->attr.sample_freq = value; 5490 } else { 5491 event->attr.sample_period = value; 5492 event->hw.sample_period = value; 5493 } 5494 5495 active = (event->state == PERF_EVENT_STATE_ACTIVE); 5496 if (active) { 5497 perf_pmu_disable(ctx->pmu); 5498 /* 5499 * We could be throttled; unthrottle now to avoid the tick 5500 * trying to unthrottle while we already re-started the event. 5501 */ 5502 if (event->hw.interrupts == MAX_INTERRUPTS) { 5503 event->hw.interrupts = 0; 5504 perf_log_throttle(event, 1); 5505 } 5506 event->pmu->stop(event, PERF_EF_UPDATE); 5507 } 5508 5509 local64_set(&event->hw.period_left, 0); 5510 5511 if (active) { 5512 event->pmu->start(event, PERF_EF_RELOAD); 5513 perf_pmu_enable(ctx->pmu); 5514 } 5515 } 5516 5517 static int perf_event_check_period(struct perf_event *event, u64 value) 5518 { 5519 return event->pmu->check_period(event, value); 5520 } 5521 5522 static int _perf_event_period(struct perf_event *event, u64 value) 5523 { 5524 if (!is_sampling_event(event)) 5525 return -EINVAL; 5526 5527 if (!value) 5528 return -EINVAL; 5529 5530 if (event->attr.freq && value > sysctl_perf_event_sample_rate) 5531 return -EINVAL; 5532 5533 if (perf_event_check_period(event, value)) 5534 return -EINVAL; 5535 5536 if (!event->attr.freq && (value & (1ULL << 63))) 5537 return -EINVAL; 5538 5539 event_function_call(event, __perf_event_period, &value); 5540 5541 return 0; 5542 } 5543 5544 int perf_event_period(struct perf_event *event, u64 value) 5545 { 5546 struct perf_event_context *ctx; 5547 int ret; 5548 5549 ctx = perf_event_ctx_lock(event); 5550 ret = _perf_event_period(event, value); 5551 perf_event_ctx_unlock(event, ctx); 5552 5553 return ret; 5554 } 5555 EXPORT_SYMBOL_GPL(perf_event_period); 5556 5557 static const struct file_operations perf_fops; 5558 5559 static inline int perf_fget_light(int fd, struct fd *p) 5560 { 5561 struct fd f = fdget(fd); 5562 if (!f.file) 5563 return -EBADF; 5564 5565 if (f.file->f_op != &perf_fops) { 5566 fdput(f); 5567 return -EBADF; 5568 } 5569 *p = f; 5570 return 0; 5571 } 5572 5573 static int perf_event_set_output(struct perf_event *event, 5574 struct perf_event *output_event); 5575 static int perf_event_set_filter(struct perf_event *event, void __user *arg); 5576 static int perf_copy_attr(struct perf_event_attr __user *uattr, 5577 struct perf_event_attr *attr); 5578 5579 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg) 5580 { 5581 void (*func)(struct perf_event *); 5582 u32 flags = arg; 5583 5584 switch (cmd) { 5585 case PERF_EVENT_IOC_ENABLE: 5586 func = _perf_event_enable; 5587 break; 5588 case PERF_EVENT_IOC_DISABLE: 5589 func = _perf_event_disable; 5590 break; 5591 case PERF_EVENT_IOC_RESET: 5592 func = _perf_event_reset; 5593 break; 5594 5595 case PERF_EVENT_IOC_REFRESH: 5596 return _perf_event_refresh(event, arg); 5597 5598 case PERF_EVENT_IOC_PERIOD: 5599 { 5600 u64 value; 5601 5602 if (copy_from_user(&value, (u64 __user *)arg, sizeof(value))) 5603 return -EFAULT; 5604 5605 return _perf_event_period(event, value); 5606 } 5607 case PERF_EVENT_IOC_ID: 5608 { 5609 u64 id = primary_event_id(event); 5610 5611 if (copy_to_user((void __user *)arg, &id, sizeof(id))) 5612 return -EFAULT; 5613 return 0; 5614 } 5615 5616 case PERF_EVENT_IOC_SET_OUTPUT: 5617 { 5618 int ret; 5619 if (arg != -1) { 5620 struct perf_event *output_event; 5621 struct fd output; 5622 ret = perf_fget_light(arg, &output); 5623 if (ret) 5624 return ret; 5625 output_event = output.file->private_data; 5626 ret = perf_event_set_output(event, output_event); 5627 fdput(output); 5628 } else { 5629 ret = perf_event_set_output(event, NULL); 5630 } 5631 return ret; 5632 } 5633 5634 case PERF_EVENT_IOC_SET_FILTER: 5635 return perf_event_set_filter(event, (void __user *)arg); 5636 5637 case PERF_EVENT_IOC_SET_BPF: 5638 { 5639 struct bpf_prog *prog; 5640 int err; 5641 5642 prog = bpf_prog_get(arg); 5643 if (IS_ERR(prog)) 5644 return PTR_ERR(prog); 5645 5646 err = perf_event_set_bpf_prog(event, prog, 0); 5647 if (err) { 5648 bpf_prog_put(prog); 5649 return err; 5650 } 5651 5652 return 0; 5653 } 5654 5655 case PERF_EVENT_IOC_PAUSE_OUTPUT: { 5656 struct perf_buffer *rb; 5657 5658 rcu_read_lock(); 5659 rb = rcu_dereference(event->rb); 5660 if (!rb || !rb->nr_pages) { 5661 rcu_read_unlock(); 5662 return -EINVAL; 5663 } 5664 rb_toggle_paused(rb, !!arg); 5665 rcu_read_unlock(); 5666 return 0; 5667 } 5668 5669 case PERF_EVENT_IOC_QUERY_BPF: 5670 return perf_event_query_prog_array(event, (void __user *)arg); 5671 5672 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: { 5673 struct perf_event_attr new_attr; 5674 int err = perf_copy_attr((struct perf_event_attr __user *)arg, 5675 &new_attr); 5676 5677 if (err) 5678 return err; 5679 5680 return perf_event_modify_attr(event, &new_attr); 5681 } 5682 default: 5683 return -ENOTTY; 5684 } 5685 5686 if (flags & PERF_IOC_FLAG_GROUP) 5687 perf_event_for_each(event, func); 5688 else 5689 perf_event_for_each_child(event, func); 5690 5691 return 0; 5692 } 5693 5694 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 5695 { 5696 struct perf_event *event = file->private_data; 5697 struct perf_event_context *ctx; 5698 long ret; 5699 5700 /* Treat ioctl like writes as it is likely a mutating operation. */ 5701 ret = security_perf_event_write(event); 5702 if (ret) 5703 return ret; 5704 5705 ctx = perf_event_ctx_lock(event); 5706 ret = _perf_ioctl(event, cmd, arg); 5707 perf_event_ctx_unlock(event, ctx); 5708 5709 return ret; 5710 } 5711 5712 #ifdef CONFIG_COMPAT 5713 static long perf_compat_ioctl(struct file *file, unsigned int cmd, 5714 unsigned long arg) 5715 { 5716 switch (_IOC_NR(cmd)) { 5717 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER): 5718 case _IOC_NR(PERF_EVENT_IOC_ID): 5719 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF): 5720 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES): 5721 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */ 5722 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) { 5723 cmd &= ~IOCSIZE_MASK; 5724 cmd |= sizeof(void *) << IOCSIZE_SHIFT; 5725 } 5726 break; 5727 } 5728 return perf_ioctl(file, cmd, arg); 5729 } 5730 #else 5731 # define perf_compat_ioctl NULL 5732 #endif 5733 5734 int perf_event_task_enable(void) 5735 { 5736 struct perf_event_context *ctx; 5737 struct perf_event *event; 5738 5739 mutex_lock(¤t->perf_event_mutex); 5740 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { 5741 ctx = perf_event_ctx_lock(event); 5742 perf_event_for_each_child(event, _perf_event_enable); 5743 perf_event_ctx_unlock(event, ctx); 5744 } 5745 mutex_unlock(¤t->perf_event_mutex); 5746 5747 return 0; 5748 } 5749 5750 int perf_event_task_disable(void) 5751 { 5752 struct perf_event_context *ctx; 5753 struct perf_event *event; 5754 5755 mutex_lock(¤t->perf_event_mutex); 5756 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { 5757 ctx = perf_event_ctx_lock(event); 5758 perf_event_for_each_child(event, _perf_event_disable); 5759 perf_event_ctx_unlock(event, ctx); 5760 } 5761 mutex_unlock(¤t->perf_event_mutex); 5762 5763 return 0; 5764 } 5765 5766 static int perf_event_index(struct perf_event *event) 5767 { 5768 if (event->hw.state & PERF_HES_STOPPED) 5769 return 0; 5770 5771 if (event->state != PERF_EVENT_STATE_ACTIVE) 5772 return 0; 5773 5774 return event->pmu->event_idx(event); 5775 } 5776 5777 static void calc_timer_values(struct perf_event *event, 5778 u64 *now, 5779 u64 *enabled, 5780 u64 *running) 5781 { 5782 u64 ctx_time; 5783 5784 *now = perf_clock(); 5785 ctx_time = event->shadow_ctx_time + *now; 5786 __perf_update_times(event, ctx_time, enabled, running); 5787 } 5788 5789 static void perf_event_init_userpage(struct perf_event *event) 5790 { 5791 struct perf_event_mmap_page *userpg; 5792 struct perf_buffer *rb; 5793 5794 rcu_read_lock(); 5795 rb = rcu_dereference(event->rb); 5796 if (!rb) 5797 goto unlock; 5798 5799 userpg = rb->user_page; 5800 5801 /* Allow new userspace to detect that bit 0 is deprecated */ 5802 userpg->cap_bit0_is_deprecated = 1; 5803 userpg->size = offsetof(struct perf_event_mmap_page, __reserved); 5804 userpg->data_offset = PAGE_SIZE; 5805 userpg->data_size = perf_data_size(rb); 5806 5807 unlock: 5808 rcu_read_unlock(); 5809 } 5810 5811 void __weak arch_perf_update_userpage( 5812 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now) 5813 { 5814 } 5815 5816 /* 5817 * Callers need to ensure there can be no nesting of this function, otherwise 5818 * the seqlock logic goes bad. We can not serialize this because the arch 5819 * code calls this from NMI context. 5820 */ 5821 void perf_event_update_userpage(struct perf_event *event) 5822 { 5823 struct perf_event_mmap_page *userpg; 5824 struct perf_buffer *rb; 5825 u64 enabled, running, now; 5826 5827 rcu_read_lock(); 5828 rb = rcu_dereference(event->rb); 5829 if (!rb) 5830 goto unlock; 5831 5832 /* 5833 * compute total_time_enabled, total_time_running 5834 * based on snapshot values taken when the event 5835 * was last scheduled in. 5836 * 5837 * we cannot simply called update_context_time() 5838 * because of locking issue as we can be called in 5839 * NMI context 5840 */ 5841 calc_timer_values(event, &now, &enabled, &running); 5842 5843 userpg = rb->user_page; 5844 /* 5845 * Disable preemption to guarantee consistent time stamps are stored to 5846 * the user page. 5847 */ 5848 preempt_disable(); 5849 ++userpg->lock; 5850 barrier(); 5851 userpg->index = perf_event_index(event); 5852 userpg->offset = perf_event_count(event); 5853 if (userpg->index) 5854 userpg->offset -= local64_read(&event->hw.prev_count); 5855 5856 userpg->time_enabled = enabled + 5857 atomic64_read(&event->child_total_time_enabled); 5858 5859 userpg->time_running = running + 5860 atomic64_read(&event->child_total_time_running); 5861 5862 arch_perf_update_userpage(event, userpg, now); 5863 5864 barrier(); 5865 ++userpg->lock; 5866 preempt_enable(); 5867 unlock: 5868 rcu_read_unlock(); 5869 } 5870 EXPORT_SYMBOL_GPL(perf_event_update_userpage); 5871 5872 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf) 5873 { 5874 struct perf_event *event = vmf->vma->vm_file->private_data; 5875 struct perf_buffer *rb; 5876 vm_fault_t ret = VM_FAULT_SIGBUS; 5877 5878 if (vmf->flags & FAULT_FLAG_MKWRITE) { 5879 if (vmf->pgoff == 0) 5880 ret = 0; 5881 return ret; 5882 } 5883 5884 rcu_read_lock(); 5885 rb = rcu_dereference(event->rb); 5886 if (!rb) 5887 goto unlock; 5888 5889 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE)) 5890 goto unlock; 5891 5892 vmf->page = perf_mmap_to_page(rb, vmf->pgoff); 5893 if (!vmf->page) 5894 goto unlock; 5895 5896 get_page(vmf->page); 5897 vmf->page->mapping = vmf->vma->vm_file->f_mapping; 5898 vmf->page->index = vmf->pgoff; 5899 5900 ret = 0; 5901 unlock: 5902 rcu_read_unlock(); 5903 5904 return ret; 5905 } 5906 5907 static void ring_buffer_attach(struct perf_event *event, 5908 struct perf_buffer *rb) 5909 { 5910 struct perf_buffer *old_rb = NULL; 5911 unsigned long flags; 5912 5913 if (event->rb) { 5914 /* 5915 * Should be impossible, we set this when removing 5916 * event->rb_entry and wait/clear when adding event->rb_entry. 5917 */ 5918 WARN_ON_ONCE(event->rcu_pending); 5919 5920 old_rb = event->rb; 5921 spin_lock_irqsave(&old_rb->event_lock, flags); 5922 list_del_rcu(&event->rb_entry); 5923 spin_unlock_irqrestore(&old_rb->event_lock, flags); 5924 5925 event->rcu_batches = get_state_synchronize_rcu(); 5926 event->rcu_pending = 1; 5927 } 5928 5929 if (rb) { 5930 if (event->rcu_pending) { 5931 cond_synchronize_rcu(event->rcu_batches); 5932 event->rcu_pending = 0; 5933 } 5934 5935 spin_lock_irqsave(&rb->event_lock, flags); 5936 list_add_rcu(&event->rb_entry, &rb->event_list); 5937 spin_unlock_irqrestore(&rb->event_lock, flags); 5938 } 5939 5940 /* 5941 * Avoid racing with perf_mmap_close(AUX): stop the event 5942 * before swizzling the event::rb pointer; if it's getting 5943 * unmapped, its aux_mmap_count will be 0 and it won't 5944 * restart. See the comment in __perf_pmu_output_stop(). 5945 * 5946 * Data will inevitably be lost when set_output is done in 5947 * mid-air, but then again, whoever does it like this is 5948 * not in for the data anyway. 5949 */ 5950 if (has_aux(event)) 5951 perf_event_stop(event, 0); 5952 5953 rcu_assign_pointer(event->rb, rb); 5954 5955 if (old_rb) { 5956 ring_buffer_put(old_rb); 5957 /* 5958 * Since we detached before setting the new rb, so that we 5959 * could attach the new rb, we could have missed a wakeup. 5960 * Provide it now. 5961 */ 5962 wake_up_all(&event->waitq); 5963 } 5964 } 5965 5966 static void ring_buffer_wakeup(struct perf_event *event) 5967 { 5968 struct perf_buffer *rb; 5969 5970 rcu_read_lock(); 5971 rb = rcu_dereference(event->rb); 5972 if (rb) { 5973 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) 5974 wake_up_all(&event->waitq); 5975 } 5976 rcu_read_unlock(); 5977 } 5978 5979 struct perf_buffer *ring_buffer_get(struct perf_event *event) 5980 { 5981 struct perf_buffer *rb; 5982 5983 rcu_read_lock(); 5984 rb = rcu_dereference(event->rb); 5985 if (rb) { 5986 if (!refcount_inc_not_zero(&rb->refcount)) 5987 rb = NULL; 5988 } 5989 rcu_read_unlock(); 5990 5991 return rb; 5992 } 5993 5994 void ring_buffer_put(struct perf_buffer *rb) 5995 { 5996 if (!refcount_dec_and_test(&rb->refcount)) 5997 return; 5998 5999 WARN_ON_ONCE(!list_empty(&rb->event_list)); 6000 6001 call_rcu(&rb->rcu_head, rb_free_rcu); 6002 } 6003 6004 static void perf_mmap_open(struct vm_area_struct *vma) 6005 { 6006 struct perf_event *event = vma->vm_file->private_data; 6007 6008 atomic_inc(&event->mmap_count); 6009 atomic_inc(&event->rb->mmap_count); 6010 6011 if (vma->vm_pgoff) 6012 atomic_inc(&event->rb->aux_mmap_count); 6013 6014 if (event->pmu->event_mapped) 6015 event->pmu->event_mapped(event, vma->vm_mm); 6016 } 6017 6018 static void perf_pmu_output_stop(struct perf_event *event); 6019 6020 /* 6021 * A buffer can be mmap()ed multiple times; either directly through the same 6022 * event, or through other events by use of perf_event_set_output(). 6023 * 6024 * In order to undo the VM accounting done by perf_mmap() we need to destroy 6025 * the buffer here, where we still have a VM context. This means we need 6026 * to detach all events redirecting to us. 6027 */ 6028 static void perf_mmap_close(struct vm_area_struct *vma) 6029 { 6030 struct perf_event *event = vma->vm_file->private_data; 6031 struct perf_buffer *rb = ring_buffer_get(event); 6032 struct user_struct *mmap_user = rb->mmap_user; 6033 int mmap_locked = rb->mmap_locked; 6034 unsigned long size = perf_data_size(rb); 6035 bool detach_rest = false; 6036 6037 if (event->pmu->event_unmapped) 6038 event->pmu->event_unmapped(event, vma->vm_mm); 6039 6040 /* 6041 * rb->aux_mmap_count will always drop before rb->mmap_count and 6042 * event->mmap_count, so it is ok to use event->mmap_mutex to 6043 * serialize with perf_mmap here. 6044 */ 6045 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff && 6046 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) { 6047 /* 6048 * Stop all AUX events that are writing to this buffer, 6049 * so that we can free its AUX pages and corresponding PMU 6050 * data. Note that after rb::aux_mmap_count dropped to zero, 6051 * they won't start any more (see perf_aux_output_begin()). 6052 */ 6053 perf_pmu_output_stop(event); 6054 6055 /* now it's safe to free the pages */ 6056 atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm); 6057 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm); 6058 6059 /* this has to be the last one */ 6060 rb_free_aux(rb); 6061 WARN_ON_ONCE(refcount_read(&rb->aux_refcount)); 6062 6063 mutex_unlock(&event->mmap_mutex); 6064 } 6065 6066 if (atomic_dec_and_test(&rb->mmap_count)) 6067 detach_rest = true; 6068 6069 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) 6070 goto out_put; 6071 6072 ring_buffer_attach(event, NULL); 6073 mutex_unlock(&event->mmap_mutex); 6074 6075 /* If there's still other mmap()s of this buffer, we're done. */ 6076 if (!detach_rest) 6077 goto out_put; 6078 6079 /* 6080 * No other mmap()s, detach from all other events that might redirect 6081 * into the now unreachable buffer. Somewhat complicated by the 6082 * fact that rb::event_lock otherwise nests inside mmap_mutex. 6083 */ 6084 again: 6085 rcu_read_lock(); 6086 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) { 6087 if (!atomic_long_inc_not_zero(&event->refcount)) { 6088 /* 6089 * This event is en-route to free_event() which will 6090 * detach it and remove it from the list. 6091 */ 6092 continue; 6093 } 6094 rcu_read_unlock(); 6095 6096 mutex_lock(&event->mmap_mutex); 6097 /* 6098 * Check we didn't race with perf_event_set_output() which can 6099 * swizzle the rb from under us while we were waiting to 6100 * acquire mmap_mutex. 6101 * 6102 * If we find a different rb; ignore this event, a next 6103 * iteration will no longer find it on the list. We have to 6104 * still restart the iteration to make sure we're not now 6105 * iterating the wrong list. 6106 */ 6107 if (event->rb == rb) 6108 ring_buffer_attach(event, NULL); 6109 6110 mutex_unlock(&event->mmap_mutex); 6111 put_event(event); 6112 6113 /* 6114 * Restart the iteration; either we're on the wrong list or 6115 * destroyed its integrity by doing a deletion. 6116 */ 6117 goto again; 6118 } 6119 rcu_read_unlock(); 6120 6121 /* 6122 * It could be there's still a few 0-ref events on the list; they'll 6123 * get cleaned up by free_event() -- they'll also still have their 6124 * ref on the rb and will free it whenever they are done with it. 6125 * 6126 * Aside from that, this buffer is 'fully' detached and unmapped, 6127 * undo the VM accounting. 6128 */ 6129 6130 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked, 6131 &mmap_user->locked_vm); 6132 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm); 6133 free_uid(mmap_user); 6134 6135 out_put: 6136 ring_buffer_put(rb); /* could be last */ 6137 } 6138 6139 static const struct vm_operations_struct perf_mmap_vmops = { 6140 .open = perf_mmap_open, 6141 .close = perf_mmap_close, /* non mergeable */ 6142 .fault = perf_mmap_fault, 6143 .page_mkwrite = perf_mmap_fault, 6144 }; 6145 6146 static int perf_mmap(struct file *file, struct vm_area_struct *vma) 6147 { 6148 struct perf_event *event = file->private_data; 6149 unsigned long user_locked, user_lock_limit; 6150 struct user_struct *user = current_user(); 6151 struct perf_buffer *rb = NULL; 6152 unsigned long locked, lock_limit; 6153 unsigned long vma_size; 6154 unsigned long nr_pages; 6155 long user_extra = 0, extra = 0; 6156 int ret = 0, flags = 0; 6157 6158 /* 6159 * Don't allow mmap() of inherited per-task counters. This would 6160 * create a performance issue due to all children writing to the 6161 * same rb. 6162 */ 6163 if (event->cpu == -1 && event->attr.inherit) 6164 return -EINVAL; 6165 6166 if (!(vma->vm_flags & VM_SHARED)) 6167 return -EINVAL; 6168 6169 ret = security_perf_event_read(event); 6170 if (ret) 6171 return ret; 6172 6173 vma_size = vma->vm_end - vma->vm_start; 6174 6175 if (vma->vm_pgoff == 0) { 6176 nr_pages = (vma_size / PAGE_SIZE) - 1; 6177 } else { 6178 /* 6179 * AUX area mapping: if rb->aux_nr_pages != 0, it's already 6180 * mapped, all subsequent mappings should have the same size 6181 * and offset. Must be above the normal perf buffer. 6182 */ 6183 u64 aux_offset, aux_size; 6184 6185 if (!event->rb) 6186 return -EINVAL; 6187 6188 nr_pages = vma_size / PAGE_SIZE; 6189 6190 mutex_lock(&event->mmap_mutex); 6191 ret = -EINVAL; 6192 6193 rb = event->rb; 6194 if (!rb) 6195 goto aux_unlock; 6196 6197 aux_offset = READ_ONCE(rb->user_page->aux_offset); 6198 aux_size = READ_ONCE(rb->user_page->aux_size); 6199 6200 if (aux_offset < perf_data_size(rb) + PAGE_SIZE) 6201 goto aux_unlock; 6202 6203 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT) 6204 goto aux_unlock; 6205 6206 /* already mapped with a different offset */ 6207 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff) 6208 goto aux_unlock; 6209 6210 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE) 6211 goto aux_unlock; 6212 6213 /* already mapped with a different size */ 6214 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages) 6215 goto aux_unlock; 6216 6217 if (!is_power_of_2(nr_pages)) 6218 goto aux_unlock; 6219 6220 if (!atomic_inc_not_zero(&rb->mmap_count)) 6221 goto aux_unlock; 6222 6223 if (rb_has_aux(rb)) { 6224 atomic_inc(&rb->aux_mmap_count); 6225 ret = 0; 6226 goto unlock; 6227 } 6228 6229 atomic_set(&rb->aux_mmap_count, 1); 6230 user_extra = nr_pages; 6231 6232 goto accounting; 6233 } 6234 6235 /* 6236 * If we have rb pages ensure they're a power-of-two number, so we 6237 * can do bitmasks instead of modulo. 6238 */ 6239 if (nr_pages != 0 && !is_power_of_2(nr_pages)) 6240 return -EINVAL; 6241 6242 if (vma_size != PAGE_SIZE * (1 + nr_pages)) 6243 return -EINVAL; 6244 6245 WARN_ON_ONCE(event->ctx->parent_ctx); 6246 again: 6247 mutex_lock(&event->mmap_mutex); 6248 if (event->rb) { 6249 if (event->rb->nr_pages != nr_pages) { 6250 ret = -EINVAL; 6251 goto unlock; 6252 } 6253 6254 if (!atomic_inc_not_zero(&event->rb->mmap_count)) { 6255 /* 6256 * Raced against perf_mmap_close() through 6257 * perf_event_set_output(). Try again, hope for better 6258 * luck. 6259 */ 6260 mutex_unlock(&event->mmap_mutex); 6261 goto again; 6262 } 6263 6264 goto unlock; 6265 } 6266 6267 user_extra = nr_pages + 1; 6268 6269 accounting: 6270 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10); 6271 6272 /* 6273 * Increase the limit linearly with more CPUs: 6274 */ 6275 user_lock_limit *= num_online_cpus(); 6276 6277 user_locked = atomic_long_read(&user->locked_vm); 6278 6279 /* 6280 * sysctl_perf_event_mlock may have changed, so that 6281 * user->locked_vm > user_lock_limit 6282 */ 6283 if (user_locked > user_lock_limit) 6284 user_locked = user_lock_limit; 6285 user_locked += user_extra; 6286 6287 if (user_locked > user_lock_limit) { 6288 /* 6289 * charge locked_vm until it hits user_lock_limit; 6290 * charge the rest from pinned_vm 6291 */ 6292 extra = user_locked - user_lock_limit; 6293 user_extra -= extra; 6294 } 6295 6296 lock_limit = rlimit(RLIMIT_MEMLOCK); 6297 lock_limit >>= PAGE_SHIFT; 6298 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra; 6299 6300 if ((locked > lock_limit) && perf_is_paranoid() && 6301 !capable(CAP_IPC_LOCK)) { 6302 ret = -EPERM; 6303 goto unlock; 6304 } 6305 6306 WARN_ON(!rb && event->rb); 6307 6308 if (vma->vm_flags & VM_WRITE) 6309 flags |= RING_BUFFER_WRITABLE; 6310 6311 if (!rb) { 6312 rb = rb_alloc(nr_pages, 6313 event->attr.watermark ? event->attr.wakeup_watermark : 0, 6314 event->cpu, flags); 6315 6316 if (!rb) { 6317 ret = -ENOMEM; 6318 goto unlock; 6319 } 6320 6321 atomic_set(&rb->mmap_count, 1); 6322 rb->mmap_user = get_current_user(); 6323 rb->mmap_locked = extra; 6324 6325 ring_buffer_attach(event, rb); 6326 6327 perf_event_init_userpage(event); 6328 perf_event_update_userpage(event); 6329 } else { 6330 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages, 6331 event->attr.aux_watermark, flags); 6332 if (!ret) 6333 rb->aux_mmap_locked = extra; 6334 } 6335 6336 unlock: 6337 if (!ret) { 6338 atomic_long_add(user_extra, &user->locked_vm); 6339 atomic64_add(extra, &vma->vm_mm->pinned_vm); 6340 6341 atomic_inc(&event->mmap_count); 6342 } else if (rb) { 6343 atomic_dec(&rb->mmap_count); 6344 } 6345 aux_unlock: 6346 mutex_unlock(&event->mmap_mutex); 6347 6348 /* 6349 * Since pinned accounting is per vm we cannot allow fork() to copy our 6350 * vma. 6351 */ 6352 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP; 6353 vma->vm_ops = &perf_mmap_vmops; 6354 6355 if (event->pmu->event_mapped) 6356 event->pmu->event_mapped(event, vma->vm_mm); 6357 6358 return ret; 6359 } 6360 6361 static int perf_fasync(int fd, struct file *filp, int on) 6362 { 6363 struct inode *inode = file_inode(filp); 6364 struct perf_event *event = filp->private_data; 6365 int retval; 6366 6367 inode_lock(inode); 6368 retval = fasync_helper(fd, filp, on, &event->fasync); 6369 inode_unlock(inode); 6370 6371 if (retval < 0) 6372 return retval; 6373 6374 return 0; 6375 } 6376 6377 static const struct file_operations perf_fops = { 6378 .llseek = no_llseek, 6379 .release = perf_release, 6380 .read = perf_read, 6381 .poll = perf_poll, 6382 .unlocked_ioctl = perf_ioctl, 6383 .compat_ioctl = perf_compat_ioctl, 6384 .mmap = perf_mmap, 6385 .fasync = perf_fasync, 6386 }; 6387 6388 /* 6389 * Perf event wakeup 6390 * 6391 * If there's data, ensure we set the poll() state and publish everything 6392 * to user-space before waking everybody up. 6393 */ 6394 6395 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event) 6396 { 6397 /* only the parent has fasync state */ 6398 if (event->parent) 6399 event = event->parent; 6400 return &event->fasync; 6401 } 6402 6403 void perf_event_wakeup(struct perf_event *event) 6404 { 6405 ring_buffer_wakeup(event); 6406 6407 if (event->pending_kill) { 6408 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill); 6409 event->pending_kill = 0; 6410 } 6411 } 6412 6413 static void perf_sigtrap(struct perf_event *event) 6414 { 6415 /* 6416 * We'd expect this to only occur if the irq_work is delayed and either 6417 * ctx->task or current has changed in the meantime. This can be the 6418 * case on architectures that do not implement arch_irq_work_raise(). 6419 */ 6420 if (WARN_ON_ONCE(event->ctx->task != current)) 6421 return; 6422 6423 /* 6424 * perf_pending_event() can race with the task exiting. 6425 */ 6426 if (current->flags & PF_EXITING) 6427 return; 6428 6429 force_sig_perf((void __user *)event->pending_addr, 6430 event->attr.type, event->attr.sig_data); 6431 } 6432 6433 static void perf_pending_event_disable(struct perf_event *event) 6434 { 6435 int cpu = READ_ONCE(event->pending_disable); 6436 6437 if (cpu < 0) 6438 return; 6439 6440 if (cpu == smp_processor_id()) { 6441 WRITE_ONCE(event->pending_disable, -1); 6442 6443 if (event->attr.sigtrap) { 6444 perf_sigtrap(event); 6445 atomic_set_release(&event->event_limit, 1); /* rearm event */ 6446 return; 6447 } 6448 6449 perf_event_disable_local(event); 6450 return; 6451 } 6452 6453 /* 6454 * CPU-A CPU-B 6455 * 6456 * perf_event_disable_inatomic() 6457 * @pending_disable = CPU-A; 6458 * irq_work_queue(); 6459 * 6460 * sched-out 6461 * @pending_disable = -1; 6462 * 6463 * sched-in 6464 * perf_event_disable_inatomic() 6465 * @pending_disable = CPU-B; 6466 * irq_work_queue(); // FAILS 6467 * 6468 * irq_work_run() 6469 * perf_pending_event() 6470 * 6471 * But the event runs on CPU-B and wants disabling there. 6472 */ 6473 irq_work_queue_on(&event->pending, cpu); 6474 } 6475 6476 static void perf_pending_event(struct irq_work *entry) 6477 { 6478 struct perf_event *event = container_of(entry, struct perf_event, pending); 6479 int rctx; 6480 6481 rctx = perf_swevent_get_recursion_context(); 6482 /* 6483 * If we 'fail' here, that's OK, it means recursion is already disabled 6484 * and we won't recurse 'further'. 6485 */ 6486 6487 perf_pending_event_disable(event); 6488 6489 if (event->pending_wakeup) { 6490 event->pending_wakeup = 0; 6491 perf_event_wakeup(event); 6492 } 6493 6494 if (rctx >= 0) 6495 perf_swevent_put_recursion_context(rctx); 6496 } 6497 6498 /* 6499 * We assume there is only KVM supporting the callbacks. 6500 * Later on, we might change it to a list if there is 6501 * another virtualization implementation supporting the callbacks. 6502 */ 6503 struct perf_guest_info_callbacks *perf_guest_cbs; 6504 6505 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) 6506 { 6507 perf_guest_cbs = cbs; 6508 return 0; 6509 } 6510 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks); 6511 6512 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) 6513 { 6514 perf_guest_cbs = NULL; 6515 return 0; 6516 } 6517 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks); 6518 6519 static void 6520 perf_output_sample_regs(struct perf_output_handle *handle, 6521 struct pt_regs *regs, u64 mask) 6522 { 6523 int bit; 6524 DECLARE_BITMAP(_mask, 64); 6525 6526 bitmap_from_u64(_mask, mask); 6527 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) { 6528 u64 val; 6529 6530 val = perf_reg_value(regs, bit); 6531 perf_output_put(handle, val); 6532 } 6533 } 6534 6535 static void perf_sample_regs_user(struct perf_regs *regs_user, 6536 struct pt_regs *regs) 6537 { 6538 if (user_mode(regs)) { 6539 regs_user->abi = perf_reg_abi(current); 6540 regs_user->regs = regs; 6541 } else if (!(current->flags & PF_KTHREAD)) { 6542 perf_get_regs_user(regs_user, regs); 6543 } else { 6544 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE; 6545 regs_user->regs = NULL; 6546 } 6547 } 6548 6549 static void perf_sample_regs_intr(struct perf_regs *regs_intr, 6550 struct pt_regs *regs) 6551 { 6552 regs_intr->regs = regs; 6553 regs_intr->abi = perf_reg_abi(current); 6554 } 6555 6556 6557 /* 6558 * Get remaining task size from user stack pointer. 6559 * 6560 * It'd be better to take stack vma map and limit this more 6561 * precisely, but there's no way to get it safely under interrupt, 6562 * so using TASK_SIZE as limit. 6563 */ 6564 static u64 perf_ustack_task_size(struct pt_regs *regs) 6565 { 6566 unsigned long addr = perf_user_stack_pointer(regs); 6567 6568 if (!addr || addr >= TASK_SIZE) 6569 return 0; 6570 6571 return TASK_SIZE - addr; 6572 } 6573 6574 static u16 6575 perf_sample_ustack_size(u16 stack_size, u16 header_size, 6576 struct pt_regs *regs) 6577 { 6578 u64 task_size; 6579 6580 /* No regs, no stack pointer, no dump. */ 6581 if (!regs) 6582 return 0; 6583 6584 /* 6585 * Check if we fit in with the requested stack size into the: 6586 * - TASK_SIZE 6587 * If we don't, we limit the size to the TASK_SIZE. 6588 * 6589 * - remaining sample size 6590 * If we don't, we customize the stack size to 6591 * fit in to the remaining sample size. 6592 */ 6593 6594 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs)); 6595 stack_size = min(stack_size, (u16) task_size); 6596 6597 /* Current header size plus static size and dynamic size. */ 6598 header_size += 2 * sizeof(u64); 6599 6600 /* Do we fit in with the current stack dump size? */ 6601 if ((u16) (header_size + stack_size) < header_size) { 6602 /* 6603 * If we overflow the maximum size for the sample, 6604 * we customize the stack dump size to fit in. 6605 */ 6606 stack_size = USHRT_MAX - header_size - sizeof(u64); 6607 stack_size = round_up(stack_size, sizeof(u64)); 6608 } 6609 6610 return stack_size; 6611 } 6612 6613 static void 6614 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size, 6615 struct pt_regs *regs) 6616 { 6617 /* Case of a kernel thread, nothing to dump */ 6618 if (!regs) { 6619 u64 size = 0; 6620 perf_output_put(handle, size); 6621 } else { 6622 unsigned long sp; 6623 unsigned int rem; 6624 u64 dyn_size; 6625 mm_segment_t fs; 6626 6627 /* 6628 * We dump: 6629 * static size 6630 * - the size requested by user or the best one we can fit 6631 * in to the sample max size 6632 * data 6633 * - user stack dump data 6634 * dynamic size 6635 * - the actual dumped size 6636 */ 6637 6638 /* Static size. */ 6639 perf_output_put(handle, dump_size); 6640 6641 /* Data. */ 6642 sp = perf_user_stack_pointer(regs); 6643 fs = force_uaccess_begin(); 6644 rem = __output_copy_user(handle, (void *) sp, dump_size); 6645 force_uaccess_end(fs); 6646 dyn_size = dump_size - rem; 6647 6648 perf_output_skip(handle, rem); 6649 6650 /* Dynamic size. */ 6651 perf_output_put(handle, dyn_size); 6652 } 6653 } 6654 6655 static unsigned long perf_prepare_sample_aux(struct perf_event *event, 6656 struct perf_sample_data *data, 6657 size_t size) 6658 { 6659 struct perf_event *sampler = event->aux_event; 6660 struct perf_buffer *rb; 6661 6662 data->aux_size = 0; 6663 6664 if (!sampler) 6665 goto out; 6666 6667 if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE)) 6668 goto out; 6669 6670 if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id())) 6671 goto out; 6672 6673 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler); 6674 if (!rb) 6675 goto out; 6676 6677 /* 6678 * If this is an NMI hit inside sampling code, don't take 6679 * the sample. See also perf_aux_sample_output(). 6680 */ 6681 if (READ_ONCE(rb->aux_in_sampling)) { 6682 data->aux_size = 0; 6683 } else { 6684 size = min_t(size_t, size, perf_aux_size(rb)); 6685 data->aux_size = ALIGN(size, sizeof(u64)); 6686 } 6687 ring_buffer_put(rb); 6688 6689 out: 6690 return data->aux_size; 6691 } 6692 6693 static long perf_pmu_snapshot_aux(struct perf_buffer *rb, 6694 struct perf_event *event, 6695 struct perf_output_handle *handle, 6696 unsigned long size) 6697 { 6698 unsigned long flags; 6699 long ret; 6700 6701 /* 6702 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler 6703 * paths. If we start calling them in NMI context, they may race with 6704 * the IRQ ones, that is, for example, re-starting an event that's just 6705 * been stopped, which is why we're using a separate callback that 6706 * doesn't change the event state. 6707 * 6708 * IRQs need to be disabled to prevent IPIs from racing with us. 6709 */ 6710 local_irq_save(flags); 6711 /* 6712 * Guard against NMI hits inside the critical section; 6713 * see also perf_prepare_sample_aux(). 6714 */ 6715 WRITE_ONCE(rb->aux_in_sampling, 1); 6716 barrier(); 6717 6718 ret = event->pmu->snapshot_aux(event, handle, size); 6719 6720 barrier(); 6721 WRITE_ONCE(rb->aux_in_sampling, 0); 6722 local_irq_restore(flags); 6723 6724 return ret; 6725 } 6726 6727 static void perf_aux_sample_output(struct perf_event *event, 6728 struct perf_output_handle *handle, 6729 struct perf_sample_data *data) 6730 { 6731 struct perf_event *sampler = event->aux_event; 6732 struct perf_buffer *rb; 6733 unsigned long pad; 6734 long size; 6735 6736 if (WARN_ON_ONCE(!sampler || !data->aux_size)) 6737 return; 6738 6739 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler); 6740 if (!rb) 6741 return; 6742 6743 size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size); 6744 6745 /* 6746 * An error here means that perf_output_copy() failed (returned a 6747 * non-zero surplus that it didn't copy), which in its current 6748 * enlightened implementation is not possible. If that changes, we'd 6749 * like to know. 6750 */ 6751 if (WARN_ON_ONCE(size < 0)) 6752 goto out_put; 6753 6754 /* 6755 * The pad comes from ALIGN()ing data->aux_size up to u64 in 6756 * perf_prepare_sample_aux(), so should not be more than that. 6757 */ 6758 pad = data->aux_size - size; 6759 if (WARN_ON_ONCE(pad >= sizeof(u64))) 6760 pad = 8; 6761 6762 if (pad) { 6763 u64 zero = 0; 6764 perf_output_copy(handle, &zero, pad); 6765 } 6766 6767 out_put: 6768 ring_buffer_put(rb); 6769 } 6770 6771 static void __perf_event_header__init_id(struct perf_event_header *header, 6772 struct perf_sample_data *data, 6773 struct perf_event *event) 6774 { 6775 u64 sample_type = event->attr.sample_type; 6776 6777 data->type = sample_type; 6778 header->size += event->id_header_size; 6779 6780 if (sample_type & PERF_SAMPLE_TID) { 6781 /* namespace issues */ 6782 data->tid_entry.pid = perf_event_pid(event, current); 6783 data->tid_entry.tid = perf_event_tid(event, current); 6784 } 6785 6786 if (sample_type & PERF_SAMPLE_TIME) 6787 data->time = perf_event_clock(event); 6788 6789 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER)) 6790 data->id = primary_event_id(event); 6791 6792 if (sample_type & PERF_SAMPLE_STREAM_ID) 6793 data->stream_id = event->id; 6794 6795 if (sample_type & PERF_SAMPLE_CPU) { 6796 data->cpu_entry.cpu = raw_smp_processor_id(); 6797 data->cpu_entry.reserved = 0; 6798 } 6799 } 6800 6801 void perf_event_header__init_id(struct perf_event_header *header, 6802 struct perf_sample_data *data, 6803 struct perf_event *event) 6804 { 6805 if (event->attr.sample_id_all) 6806 __perf_event_header__init_id(header, data, event); 6807 } 6808 6809 static void __perf_event__output_id_sample(struct perf_output_handle *handle, 6810 struct perf_sample_data *data) 6811 { 6812 u64 sample_type = data->type; 6813 6814 if (sample_type & PERF_SAMPLE_TID) 6815 perf_output_put(handle, data->tid_entry); 6816 6817 if (sample_type & PERF_SAMPLE_TIME) 6818 perf_output_put(handle, data->time); 6819 6820 if (sample_type & PERF_SAMPLE_ID) 6821 perf_output_put(handle, data->id); 6822 6823 if (sample_type & PERF_SAMPLE_STREAM_ID) 6824 perf_output_put(handle, data->stream_id); 6825 6826 if (sample_type & PERF_SAMPLE_CPU) 6827 perf_output_put(handle, data->cpu_entry); 6828 6829 if (sample_type & PERF_SAMPLE_IDENTIFIER) 6830 perf_output_put(handle, data->id); 6831 } 6832 6833 void perf_event__output_id_sample(struct perf_event *event, 6834 struct perf_output_handle *handle, 6835 struct perf_sample_data *sample) 6836 { 6837 if (event->attr.sample_id_all) 6838 __perf_event__output_id_sample(handle, sample); 6839 } 6840 6841 static void perf_output_read_one(struct perf_output_handle *handle, 6842 struct perf_event *event, 6843 u64 enabled, u64 running) 6844 { 6845 u64 read_format = event->attr.read_format; 6846 u64 values[4]; 6847 int n = 0; 6848 6849 values[n++] = perf_event_count(event); 6850 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { 6851 values[n++] = enabled + 6852 atomic64_read(&event->child_total_time_enabled); 6853 } 6854 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { 6855 values[n++] = running + 6856 atomic64_read(&event->child_total_time_running); 6857 } 6858 if (read_format & PERF_FORMAT_ID) 6859 values[n++] = primary_event_id(event); 6860 6861 __output_copy(handle, values, n * sizeof(u64)); 6862 } 6863 6864 static void perf_output_read_group(struct perf_output_handle *handle, 6865 struct perf_event *event, 6866 u64 enabled, u64 running) 6867 { 6868 struct perf_event *leader = event->group_leader, *sub; 6869 u64 read_format = event->attr.read_format; 6870 u64 values[5]; 6871 int n = 0; 6872 6873 values[n++] = 1 + leader->nr_siblings; 6874 6875 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 6876 values[n++] = enabled; 6877 6878 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 6879 values[n++] = running; 6880 6881 if ((leader != event) && 6882 (leader->state == PERF_EVENT_STATE_ACTIVE)) 6883 leader->pmu->read(leader); 6884 6885 values[n++] = perf_event_count(leader); 6886 if (read_format & PERF_FORMAT_ID) 6887 values[n++] = primary_event_id(leader); 6888 6889 __output_copy(handle, values, n * sizeof(u64)); 6890 6891 for_each_sibling_event(sub, leader) { 6892 n = 0; 6893 6894 if ((sub != event) && 6895 (sub->state == PERF_EVENT_STATE_ACTIVE)) 6896 sub->pmu->read(sub); 6897 6898 values[n++] = perf_event_count(sub); 6899 if (read_format & PERF_FORMAT_ID) 6900 values[n++] = primary_event_id(sub); 6901 6902 __output_copy(handle, values, n * sizeof(u64)); 6903 } 6904 } 6905 6906 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\ 6907 PERF_FORMAT_TOTAL_TIME_RUNNING) 6908 6909 /* 6910 * XXX PERF_SAMPLE_READ vs inherited events seems difficult. 6911 * 6912 * The problem is that its both hard and excessively expensive to iterate the 6913 * child list, not to mention that its impossible to IPI the children running 6914 * on another CPU, from interrupt/NMI context. 6915 */ 6916 static void perf_output_read(struct perf_output_handle *handle, 6917 struct perf_event *event) 6918 { 6919 u64 enabled = 0, running = 0, now; 6920 u64 read_format = event->attr.read_format; 6921 6922 /* 6923 * compute total_time_enabled, total_time_running 6924 * based on snapshot values taken when the event 6925 * was last scheduled in. 6926 * 6927 * we cannot simply called update_context_time() 6928 * because of locking issue as we are called in 6929 * NMI context 6930 */ 6931 if (read_format & PERF_FORMAT_TOTAL_TIMES) 6932 calc_timer_values(event, &now, &enabled, &running); 6933 6934 if (event->attr.read_format & PERF_FORMAT_GROUP) 6935 perf_output_read_group(handle, event, enabled, running); 6936 else 6937 perf_output_read_one(handle, event, enabled, running); 6938 } 6939 6940 static inline bool perf_sample_save_hw_index(struct perf_event *event) 6941 { 6942 return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_HW_INDEX; 6943 } 6944 6945 void perf_output_sample(struct perf_output_handle *handle, 6946 struct perf_event_header *header, 6947 struct perf_sample_data *data, 6948 struct perf_event *event) 6949 { 6950 u64 sample_type = data->type; 6951 6952 perf_output_put(handle, *header); 6953 6954 if (sample_type & PERF_SAMPLE_IDENTIFIER) 6955 perf_output_put(handle, data->id); 6956 6957 if (sample_type & PERF_SAMPLE_IP) 6958 perf_output_put(handle, data->ip); 6959 6960 if (sample_type & PERF_SAMPLE_TID) 6961 perf_output_put(handle, data->tid_entry); 6962 6963 if (sample_type & PERF_SAMPLE_TIME) 6964 perf_output_put(handle, data->time); 6965 6966 if (sample_type & PERF_SAMPLE_ADDR) 6967 perf_output_put(handle, data->addr); 6968 6969 if (sample_type & PERF_SAMPLE_ID) 6970 perf_output_put(handle, data->id); 6971 6972 if (sample_type & PERF_SAMPLE_STREAM_ID) 6973 perf_output_put(handle, data->stream_id); 6974 6975 if (sample_type & PERF_SAMPLE_CPU) 6976 perf_output_put(handle, data->cpu_entry); 6977 6978 if (sample_type & PERF_SAMPLE_PERIOD) 6979 perf_output_put(handle, data->period); 6980 6981 if (sample_type & PERF_SAMPLE_READ) 6982 perf_output_read(handle, event); 6983 6984 if (sample_type & PERF_SAMPLE_CALLCHAIN) { 6985 int size = 1; 6986 6987 size += data->callchain->nr; 6988 size *= sizeof(u64); 6989 __output_copy(handle, data->callchain, size); 6990 } 6991 6992 if (sample_type & PERF_SAMPLE_RAW) { 6993 struct perf_raw_record *raw = data->raw; 6994 6995 if (raw) { 6996 struct perf_raw_frag *frag = &raw->frag; 6997 6998 perf_output_put(handle, raw->size); 6999 do { 7000 if (frag->copy) { 7001 __output_custom(handle, frag->copy, 7002 frag->data, frag->size); 7003 } else { 7004 __output_copy(handle, frag->data, 7005 frag->size); 7006 } 7007 if (perf_raw_frag_last(frag)) 7008 break; 7009 frag = frag->next; 7010 } while (1); 7011 if (frag->pad) 7012 __output_skip(handle, NULL, frag->pad); 7013 } else { 7014 struct { 7015 u32 size; 7016 u32 data; 7017 } raw = { 7018 .size = sizeof(u32), 7019 .data = 0, 7020 }; 7021 perf_output_put(handle, raw); 7022 } 7023 } 7024 7025 if (sample_type & PERF_SAMPLE_BRANCH_STACK) { 7026 if (data->br_stack) { 7027 size_t size; 7028 7029 size = data->br_stack->nr 7030 * sizeof(struct perf_branch_entry); 7031 7032 perf_output_put(handle, data->br_stack->nr); 7033 if (perf_sample_save_hw_index(event)) 7034 perf_output_put(handle, data->br_stack->hw_idx); 7035 perf_output_copy(handle, data->br_stack->entries, size); 7036 } else { 7037 /* 7038 * we always store at least the value of nr 7039 */ 7040 u64 nr = 0; 7041 perf_output_put(handle, nr); 7042 } 7043 } 7044 7045 if (sample_type & PERF_SAMPLE_REGS_USER) { 7046 u64 abi = data->regs_user.abi; 7047 7048 /* 7049 * If there are no regs to dump, notice it through 7050 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). 7051 */ 7052 perf_output_put(handle, abi); 7053 7054 if (abi) { 7055 u64 mask = event->attr.sample_regs_user; 7056 perf_output_sample_regs(handle, 7057 data->regs_user.regs, 7058 mask); 7059 } 7060 } 7061 7062 if (sample_type & PERF_SAMPLE_STACK_USER) { 7063 perf_output_sample_ustack(handle, 7064 data->stack_user_size, 7065 data->regs_user.regs); 7066 } 7067 7068 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE) 7069 perf_output_put(handle, data->weight.full); 7070 7071 if (sample_type & PERF_SAMPLE_DATA_SRC) 7072 perf_output_put(handle, data->data_src.val); 7073 7074 if (sample_type & PERF_SAMPLE_TRANSACTION) 7075 perf_output_put(handle, data->txn); 7076 7077 if (sample_type & PERF_SAMPLE_REGS_INTR) { 7078 u64 abi = data->regs_intr.abi; 7079 /* 7080 * If there are no regs to dump, notice it through 7081 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). 7082 */ 7083 perf_output_put(handle, abi); 7084 7085 if (abi) { 7086 u64 mask = event->attr.sample_regs_intr; 7087 7088 perf_output_sample_regs(handle, 7089 data->regs_intr.regs, 7090 mask); 7091 } 7092 } 7093 7094 if (sample_type & PERF_SAMPLE_PHYS_ADDR) 7095 perf_output_put(handle, data->phys_addr); 7096 7097 if (sample_type & PERF_SAMPLE_CGROUP) 7098 perf_output_put(handle, data->cgroup); 7099 7100 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE) 7101 perf_output_put(handle, data->data_page_size); 7102 7103 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE) 7104 perf_output_put(handle, data->code_page_size); 7105 7106 if (sample_type & PERF_SAMPLE_AUX) { 7107 perf_output_put(handle, data->aux_size); 7108 7109 if (data->aux_size) 7110 perf_aux_sample_output(event, handle, data); 7111 } 7112 7113 if (!event->attr.watermark) { 7114 int wakeup_events = event->attr.wakeup_events; 7115 7116 if (wakeup_events) { 7117 struct perf_buffer *rb = handle->rb; 7118 int events = local_inc_return(&rb->events); 7119 7120 if (events >= wakeup_events) { 7121 local_sub(wakeup_events, &rb->events); 7122 local_inc(&rb->wakeup); 7123 } 7124 } 7125 } 7126 } 7127 7128 static u64 perf_virt_to_phys(u64 virt) 7129 { 7130 u64 phys_addr = 0; 7131 struct page *p = NULL; 7132 7133 if (!virt) 7134 return 0; 7135 7136 if (virt >= TASK_SIZE) { 7137 /* If it's vmalloc()d memory, leave phys_addr as 0 */ 7138 if (virt_addr_valid((void *)(uintptr_t)virt) && 7139 !(virt >= VMALLOC_START && virt < VMALLOC_END)) 7140 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt); 7141 } else { 7142 /* 7143 * Walking the pages tables for user address. 7144 * Interrupts are disabled, so it prevents any tear down 7145 * of the page tables. 7146 * Try IRQ-safe get_user_page_fast_only first. 7147 * If failed, leave phys_addr as 0. 7148 */ 7149 if (current->mm != NULL) { 7150 pagefault_disable(); 7151 if (get_user_page_fast_only(virt, 0, &p)) 7152 phys_addr = page_to_phys(p) + virt % PAGE_SIZE; 7153 pagefault_enable(); 7154 } 7155 7156 if (p) 7157 put_page(p); 7158 } 7159 7160 return phys_addr; 7161 } 7162 7163 /* 7164 * Return the pagetable size of a given virtual address. 7165 */ 7166 static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr) 7167 { 7168 u64 size = 0; 7169 7170 #ifdef CONFIG_HAVE_FAST_GUP 7171 pgd_t *pgdp, pgd; 7172 p4d_t *p4dp, p4d; 7173 pud_t *pudp, pud; 7174 pmd_t *pmdp, pmd; 7175 pte_t *ptep, pte; 7176 7177 pgdp = pgd_offset(mm, addr); 7178 pgd = READ_ONCE(*pgdp); 7179 if (pgd_none(pgd)) 7180 return 0; 7181 7182 if (pgd_leaf(pgd)) 7183 return pgd_leaf_size(pgd); 7184 7185 p4dp = p4d_offset_lockless(pgdp, pgd, addr); 7186 p4d = READ_ONCE(*p4dp); 7187 if (!p4d_present(p4d)) 7188 return 0; 7189 7190 if (p4d_leaf(p4d)) 7191 return p4d_leaf_size(p4d); 7192 7193 pudp = pud_offset_lockless(p4dp, p4d, addr); 7194 pud = READ_ONCE(*pudp); 7195 if (!pud_present(pud)) 7196 return 0; 7197 7198 if (pud_leaf(pud)) 7199 return pud_leaf_size(pud); 7200 7201 pmdp = pmd_offset_lockless(pudp, pud, addr); 7202 pmd = READ_ONCE(*pmdp); 7203 if (!pmd_present(pmd)) 7204 return 0; 7205 7206 if (pmd_leaf(pmd)) 7207 return pmd_leaf_size(pmd); 7208 7209 ptep = pte_offset_map(&pmd, addr); 7210 pte = ptep_get_lockless(ptep); 7211 if (pte_present(pte)) 7212 size = pte_leaf_size(pte); 7213 pte_unmap(ptep); 7214 #endif /* CONFIG_HAVE_FAST_GUP */ 7215 7216 return size; 7217 } 7218 7219 static u64 perf_get_page_size(unsigned long addr) 7220 { 7221 struct mm_struct *mm; 7222 unsigned long flags; 7223 u64 size; 7224 7225 if (!addr) 7226 return 0; 7227 7228 /* 7229 * Software page-table walkers must disable IRQs, 7230 * which prevents any tear down of the page tables. 7231 */ 7232 local_irq_save(flags); 7233 7234 mm = current->mm; 7235 if (!mm) { 7236 /* 7237 * For kernel threads and the like, use init_mm so that 7238 * we can find kernel memory. 7239 */ 7240 mm = &init_mm; 7241 } 7242 7243 size = perf_get_pgtable_size(mm, addr); 7244 7245 local_irq_restore(flags); 7246 7247 return size; 7248 } 7249 7250 static struct perf_callchain_entry __empty_callchain = { .nr = 0, }; 7251 7252 struct perf_callchain_entry * 7253 perf_callchain(struct perf_event *event, struct pt_regs *regs) 7254 { 7255 bool kernel = !event->attr.exclude_callchain_kernel; 7256 bool user = !event->attr.exclude_callchain_user; 7257 /* Disallow cross-task user callchains. */ 7258 bool crosstask = event->ctx->task && event->ctx->task != current; 7259 const u32 max_stack = event->attr.sample_max_stack; 7260 struct perf_callchain_entry *callchain; 7261 7262 if (!kernel && !user) 7263 return &__empty_callchain; 7264 7265 callchain = get_perf_callchain(regs, 0, kernel, user, 7266 max_stack, crosstask, true); 7267 return callchain ?: &__empty_callchain; 7268 } 7269 7270 void perf_prepare_sample(struct perf_event_header *header, 7271 struct perf_sample_data *data, 7272 struct perf_event *event, 7273 struct pt_regs *regs) 7274 { 7275 u64 sample_type = event->attr.sample_type; 7276 7277 header->type = PERF_RECORD_SAMPLE; 7278 header->size = sizeof(*header) + event->header_size; 7279 7280 header->misc = 0; 7281 header->misc |= perf_misc_flags(regs); 7282 7283 __perf_event_header__init_id(header, data, event); 7284 7285 if (sample_type & (PERF_SAMPLE_IP | PERF_SAMPLE_CODE_PAGE_SIZE)) 7286 data->ip = perf_instruction_pointer(regs); 7287 7288 if (sample_type & PERF_SAMPLE_CALLCHAIN) { 7289 int size = 1; 7290 7291 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY)) 7292 data->callchain = perf_callchain(event, regs); 7293 7294 size += data->callchain->nr; 7295 7296 header->size += size * sizeof(u64); 7297 } 7298 7299 if (sample_type & PERF_SAMPLE_RAW) { 7300 struct perf_raw_record *raw = data->raw; 7301 int size; 7302 7303 if (raw) { 7304 struct perf_raw_frag *frag = &raw->frag; 7305 u32 sum = 0; 7306 7307 do { 7308 sum += frag->size; 7309 if (perf_raw_frag_last(frag)) 7310 break; 7311 frag = frag->next; 7312 } while (1); 7313 7314 size = round_up(sum + sizeof(u32), sizeof(u64)); 7315 raw->size = size - sizeof(u32); 7316 frag->pad = raw->size - sum; 7317 } else { 7318 size = sizeof(u64); 7319 } 7320 7321 header->size += size; 7322 } 7323 7324 if (sample_type & PERF_SAMPLE_BRANCH_STACK) { 7325 int size = sizeof(u64); /* nr */ 7326 if (data->br_stack) { 7327 if (perf_sample_save_hw_index(event)) 7328 size += sizeof(u64); 7329 7330 size += data->br_stack->nr 7331 * sizeof(struct perf_branch_entry); 7332 } 7333 header->size += size; 7334 } 7335 7336 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER)) 7337 perf_sample_regs_user(&data->regs_user, regs); 7338 7339 if (sample_type & PERF_SAMPLE_REGS_USER) { 7340 /* regs dump ABI info */ 7341 int size = sizeof(u64); 7342 7343 if (data->regs_user.regs) { 7344 u64 mask = event->attr.sample_regs_user; 7345 size += hweight64(mask) * sizeof(u64); 7346 } 7347 7348 header->size += size; 7349 } 7350 7351 if (sample_type & PERF_SAMPLE_STACK_USER) { 7352 /* 7353 * Either we need PERF_SAMPLE_STACK_USER bit to be always 7354 * processed as the last one or have additional check added 7355 * in case new sample type is added, because we could eat 7356 * up the rest of the sample size. 7357 */ 7358 u16 stack_size = event->attr.sample_stack_user; 7359 u16 size = sizeof(u64); 7360 7361 stack_size = perf_sample_ustack_size(stack_size, header->size, 7362 data->regs_user.regs); 7363 7364 /* 7365 * If there is something to dump, add space for the dump 7366 * itself and for the field that tells the dynamic size, 7367 * which is how many have been actually dumped. 7368 */ 7369 if (stack_size) 7370 size += sizeof(u64) + stack_size; 7371 7372 data->stack_user_size = stack_size; 7373 header->size += size; 7374 } 7375 7376 if (sample_type & PERF_SAMPLE_REGS_INTR) { 7377 /* regs dump ABI info */ 7378 int size = sizeof(u64); 7379 7380 perf_sample_regs_intr(&data->regs_intr, regs); 7381 7382 if (data->regs_intr.regs) { 7383 u64 mask = event->attr.sample_regs_intr; 7384 7385 size += hweight64(mask) * sizeof(u64); 7386 } 7387 7388 header->size += size; 7389 } 7390 7391 if (sample_type & PERF_SAMPLE_PHYS_ADDR) 7392 data->phys_addr = perf_virt_to_phys(data->addr); 7393 7394 #ifdef CONFIG_CGROUP_PERF 7395 if (sample_type & PERF_SAMPLE_CGROUP) { 7396 struct cgroup *cgrp; 7397 7398 /* protected by RCU */ 7399 cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup; 7400 data->cgroup = cgroup_id(cgrp); 7401 } 7402 #endif 7403 7404 /* 7405 * PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't 7406 * require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr, 7407 * but the value will not dump to the userspace. 7408 */ 7409 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE) 7410 data->data_page_size = perf_get_page_size(data->addr); 7411 7412 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE) 7413 data->code_page_size = perf_get_page_size(data->ip); 7414 7415 if (sample_type & PERF_SAMPLE_AUX) { 7416 u64 size; 7417 7418 header->size += sizeof(u64); /* size */ 7419 7420 /* 7421 * Given the 16bit nature of header::size, an AUX sample can 7422 * easily overflow it, what with all the preceding sample bits. 7423 * Make sure this doesn't happen by using up to U16_MAX bytes 7424 * per sample in total (rounded down to 8 byte boundary). 7425 */ 7426 size = min_t(size_t, U16_MAX - header->size, 7427 event->attr.aux_sample_size); 7428 size = rounddown(size, 8); 7429 size = perf_prepare_sample_aux(event, data, size); 7430 7431 WARN_ON_ONCE(size + header->size > U16_MAX); 7432 header->size += size; 7433 } 7434 /* 7435 * If you're adding more sample types here, you likely need to do 7436 * something about the overflowing header::size, like repurpose the 7437 * lowest 3 bits of size, which should be always zero at the moment. 7438 * This raises a more important question, do we really need 512k sized 7439 * samples and why, so good argumentation is in order for whatever you 7440 * do here next. 7441 */ 7442 WARN_ON_ONCE(header->size & 7); 7443 } 7444 7445 static __always_inline int 7446 __perf_event_output(struct perf_event *event, 7447 struct perf_sample_data *data, 7448 struct pt_regs *regs, 7449 int (*output_begin)(struct perf_output_handle *, 7450 struct perf_sample_data *, 7451 struct perf_event *, 7452 unsigned int)) 7453 { 7454 struct perf_output_handle handle; 7455 struct perf_event_header header; 7456 int err; 7457 7458 /* protect the callchain buffers */ 7459 rcu_read_lock(); 7460 7461 perf_prepare_sample(&header, data, event, regs); 7462 7463 err = output_begin(&handle, data, event, header.size); 7464 if (err) 7465 goto exit; 7466 7467 perf_output_sample(&handle, &header, data, event); 7468 7469 perf_output_end(&handle); 7470 7471 exit: 7472 rcu_read_unlock(); 7473 return err; 7474 } 7475 7476 void 7477 perf_event_output_forward(struct perf_event *event, 7478 struct perf_sample_data *data, 7479 struct pt_regs *regs) 7480 { 7481 __perf_event_output(event, data, regs, perf_output_begin_forward); 7482 } 7483 7484 void 7485 perf_event_output_backward(struct perf_event *event, 7486 struct perf_sample_data *data, 7487 struct pt_regs *regs) 7488 { 7489 __perf_event_output(event, data, regs, perf_output_begin_backward); 7490 } 7491 7492 int 7493 perf_event_output(struct perf_event *event, 7494 struct perf_sample_data *data, 7495 struct pt_regs *regs) 7496 { 7497 return __perf_event_output(event, data, regs, perf_output_begin); 7498 } 7499 7500 /* 7501 * read event_id 7502 */ 7503 7504 struct perf_read_event { 7505 struct perf_event_header header; 7506 7507 u32 pid; 7508 u32 tid; 7509 }; 7510 7511 static void 7512 perf_event_read_event(struct perf_event *event, 7513 struct task_struct *task) 7514 { 7515 struct perf_output_handle handle; 7516 struct perf_sample_data sample; 7517 struct perf_read_event read_event = { 7518 .header = { 7519 .type = PERF_RECORD_READ, 7520 .misc = 0, 7521 .size = sizeof(read_event) + event->read_size, 7522 }, 7523 .pid = perf_event_pid(event, task), 7524 .tid = perf_event_tid(event, task), 7525 }; 7526 int ret; 7527 7528 perf_event_header__init_id(&read_event.header, &sample, event); 7529 ret = perf_output_begin(&handle, &sample, event, read_event.header.size); 7530 if (ret) 7531 return; 7532 7533 perf_output_put(&handle, read_event); 7534 perf_output_read(&handle, event); 7535 perf_event__output_id_sample(event, &handle, &sample); 7536 7537 perf_output_end(&handle); 7538 } 7539 7540 typedef void (perf_iterate_f)(struct perf_event *event, void *data); 7541 7542 static void 7543 perf_iterate_ctx(struct perf_event_context *ctx, 7544 perf_iterate_f output, 7545 void *data, bool all) 7546 { 7547 struct perf_event *event; 7548 7549 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 7550 if (!all) { 7551 if (event->state < PERF_EVENT_STATE_INACTIVE) 7552 continue; 7553 if (!event_filter_match(event)) 7554 continue; 7555 } 7556 7557 output(event, data); 7558 } 7559 } 7560 7561 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data) 7562 { 7563 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events); 7564 struct perf_event *event; 7565 7566 list_for_each_entry_rcu(event, &pel->list, sb_list) { 7567 /* 7568 * Skip events that are not fully formed yet; ensure that 7569 * if we observe event->ctx, both event and ctx will be 7570 * complete enough. See perf_install_in_context(). 7571 */ 7572 if (!smp_load_acquire(&event->ctx)) 7573 continue; 7574 7575 if (event->state < PERF_EVENT_STATE_INACTIVE) 7576 continue; 7577 if (!event_filter_match(event)) 7578 continue; 7579 output(event, data); 7580 } 7581 } 7582 7583 /* 7584 * Iterate all events that need to receive side-band events. 7585 * 7586 * For new callers; ensure that account_pmu_sb_event() includes 7587 * your event, otherwise it might not get delivered. 7588 */ 7589 static void 7590 perf_iterate_sb(perf_iterate_f output, void *data, 7591 struct perf_event_context *task_ctx) 7592 { 7593 struct perf_event_context *ctx; 7594 int ctxn; 7595 7596 rcu_read_lock(); 7597 preempt_disable(); 7598 7599 /* 7600 * If we have task_ctx != NULL we only notify the task context itself. 7601 * The task_ctx is set only for EXIT events before releasing task 7602 * context. 7603 */ 7604 if (task_ctx) { 7605 perf_iterate_ctx(task_ctx, output, data, false); 7606 goto done; 7607 } 7608 7609 perf_iterate_sb_cpu(output, data); 7610 7611 for_each_task_context_nr(ctxn) { 7612 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); 7613 if (ctx) 7614 perf_iterate_ctx(ctx, output, data, false); 7615 } 7616 done: 7617 preempt_enable(); 7618 rcu_read_unlock(); 7619 } 7620 7621 /* 7622 * Clear all file-based filters at exec, they'll have to be 7623 * re-instated when/if these objects are mmapped again. 7624 */ 7625 static void perf_event_addr_filters_exec(struct perf_event *event, void *data) 7626 { 7627 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 7628 struct perf_addr_filter *filter; 7629 unsigned int restart = 0, count = 0; 7630 unsigned long flags; 7631 7632 if (!has_addr_filter(event)) 7633 return; 7634 7635 raw_spin_lock_irqsave(&ifh->lock, flags); 7636 list_for_each_entry(filter, &ifh->list, entry) { 7637 if (filter->path.dentry) { 7638 event->addr_filter_ranges[count].start = 0; 7639 event->addr_filter_ranges[count].size = 0; 7640 restart++; 7641 } 7642 7643 count++; 7644 } 7645 7646 if (restart) 7647 event->addr_filters_gen++; 7648 raw_spin_unlock_irqrestore(&ifh->lock, flags); 7649 7650 if (restart) 7651 perf_event_stop(event, 1); 7652 } 7653 7654 void perf_event_exec(void) 7655 { 7656 struct perf_event_context *ctx; 7657 int ctxn; 7658 7659 for_each_task_context_nr(ctxn) { 7660 perf_event_enable_on_exec(ctxn); 7661 perf_event_remove_on_exec(ctxn); 7662 7663 rcu_read_lock(); 7664 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); 7665 if (ctx) { 7666 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, 7667 NULL, true); 7668 } 7669 rcu_read_unlock(); 7670 } 7671 } 7672 7673 struct remote_output { 7674 struct perf_buffer *rb; 7675 int err; 7676 }; 7677 7678 static void __perf_event_output_stop(struct perf_event *event, void *data) 7679 { 7680 struct perf_event *parent = event->parent; 7681 struct remote_output *ro = data; 7682 struct perf_buffer *rb = ro->rb; 7683 struct stop_event_data sd = { 7684 .event = event, 7685 }; 7686 7687 if (!has_aux(event)) 7688 return; 7689 7690 if (!parent) 7691 parent = event; 7692 7693 /* 7694 * In case of inheritance, it will be the parent that links to the 7695 * ring-buffer, but it will be the child that's actually using it. 7696 * 7697 * We are using event::rb to determine if the event should be stopped, 7698 * however this may race with ring_buffer_attach() (through set_output), 7699 * which will make us skip the event that actually needs to be stopped. 7700 * So ring_buffer_attach() has to stop an aux event before re-assigning 7701 * its rb pointer. 7702 */ 7703 if (rcu_dereference(parent->rb) == rb) 7704 ro->err = __perf_event_stop(&sd); 7705 } 7706 7707 static int __perf_pmu_output_stop(void *info) 7708 { 7709 struct perf_event *event = info; 7710 struct pmu *pmu = event->ctx->pmu; 7711 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 7712 struct remote_output ro = { 7713 .rb = event->rb, 7714 }; 7715 7716 rcu_read_lock(); 7717 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false); 7718 if (cpuctx->task_ctx) 7719 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop, 7720 &ro, false); 7721 rcu_read_unlock(); 7722 7723 return ro.err; 7724 } 7725 7726 static void perf_pmu_output_stop(struct perf_event *event) 7727 { 7728 struct perf_event *iter; 7729 int err, cpu; 7730 7731 restart: 7732 rcu_read_lock(); 7733 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) { 7734 /* 7735 * For per-CPU events, we need to make sure that neither they 7736 * nor their children are running; for cpu==-1 events it's 7737 * sufficient to stop the event itself if it's active, since 7738 * it can't have children. 7739 */ 7740 cpu = iter->cpu; 7741 if (cpu == -1) 7742 cpu = READ_ONCE(iter->oncpu); 7743 7744 if (cpu == -1) 7745 continue; 7746 7747 err = cpu_function_call(cpu, __perf_pmu_output_stop, event); 7748 if (err == -EAGAIN) { 7749 rcu_read_unlock(); 7750 goto restart; 7751 } 7752 } 7753 rcu_read_unlock(); 7754 } 7755 7756 /* 7757 * task tracking -- fork/exit 7758 * 7759 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task 7760 */ 7761 7762 struct perf_task_event { 7763 struct task_struct *task; 7764 struct perf_event_context *task_ctx; 7765 7766 struct { 7767 struct perf_event_header header; 7768 7769 u32 pid; 7770 u32 ppid; 7771 u32 tid; 7772 u32 ptid; 7773 u64 time; 7774 } event_id; 7775 }; 7776 7777 static int perf_event_task_match(struct perf_event *event) 7778 { 7779 return event->attr.comm || event->attr.mmap || 7780 event->attr.mmap2 || event->attr.mmap_data || 7781 event->attr.task; 7782 } 7783 7784 static void perf_event_task_output(struct perf_event *event, 7785 void *data) 7786 { 7787 struct perf_task_event *task_event = data; 7788 struct perf_output_handle handle; 7789 struct perf_sample_data sample; 7790 struct task_struct *task = task_event->task; 7791 int ret, size = task_event->event_id.header.size; 7792 7793 if (!perf_event_task_match(event)) 7794 return; 7795 7796 perf_event_header__init_id(&task_event->event_id.header, &sample, event); 7797 7798 ret = perf_output_begin(&handle, &sample, event, 7799 task_event->event_id.header.size); 7800 if (ret) 7801 goto out; 7802 7803 task_event->event_id.pid = perf_event_pid(event, task); 7804 task_event->event_id.tid = perf_event_tid(event, task); 7805 7806 if (task_event->event_id.header.type == PERF_RECORD_EXIT) { 7807 task_event->event_id.ppid = perf_event_pid(event, 7808 task->real_parent); 7809 task_event->event_id.ptid = perf_event_pid(event, 7810 task->real_parent); 7811 } else { /* PERF_RECORD_FORK */ 7812 task_event->event_id.ppid = perf_event_pid(event, current); 7813 task_event->event_id.ptid = perf_event_tid(event, current); 7814 } 7815 7816 task_event->event_id.time = perf_event_clock(event); 7817 7818 perf_output_put(&handle, task_event->event_id); 7819 7820 perf_event__output_id_sample(event, &handle, &sample); 7821 7822 perf_output_end(&handle); 7823 out: 7824 task_event->event_id.header.size = size; 7825 } 7826 7827 static void perf_event_task(struct task_struct *task, 7828 struct perf_event_context *task_ctx, 7829 int new) 7830 { 7831 struct perf_task_event task_event; 7832 7833 if (!atomic_read(&nr_comm_events) && 7834 !atomic_read(&nr_mmap_events) && 7835 !atomic_read(&nr_task_events)) 7836 return; 7837 7838 task_event = (struct perf_task_event){ 7839 .task = task, 7840 .task_ctx = task_ctx, 7841 .event_id = { 7842 .header = { 7843 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT, 7844 .misc = 0, 7845 .size = sizeof(task_event.event_id), 7846 }, 7847 /* .pid */ 7848 /* .ppid */ 7849 /* .tid */ 7850 /* .ptid */ 7851 /* .time */ 7852 }, 7853 }; 7854 7855 perf_iterate_sb(perf_event_task_output, 7856 &task_event, 7857 task_ctx); 7858 } 7859 7860 void perf_event_fork(struct task_struct *task) 7861 { 7862 perf_event_task(task, NULL, 1); 7863 perf_event_namespaces(task); 7864 } 7865 7866 /* 7867 * comm tracking 7868 */ 7869 7870 struct perf_comm_event { 7871 struct task_struct *task; 7872 char *comm; 7873 int comm_size; 7874 7875 struct { 7876 struct perf_event_header header; 7877 7878 u32 pid; 7879 u32 tid; 7880 } event_id; 7881 }; 7882 7883 static int perf_event_comm_match(struct perf_event *event) 7884 { 7885 return event->attr.comm; 7886 } 7887 7888 static void perf_event_comm_output(struct perf_event *event, 7889 void *data) 7890 { 7891 struct perf_comm_event *comm_event = data; 7892 struct perf_output_handle handle; 7893 struct perf_sample_data sample; 7894 int size = comm_event->event_id.header.size; 7895 int ret; 7896 7897 if (!perf_event_comm_match(event)) 7898 return; 7899 7900 perf_event_header__init_id(&comm_event->event_id.header, &sample, event); 7901 ret = perf_output_begin(&handle, &sample, event, 7902 comm_event->event_id.header.size); 7903 7904 if (ret) 7905 goto out; 7906 7907 comm_event->event_id.pid = perf_event_pid(event, comm_event->task); 7908 comm_event->event_id.tid = perf_event_tid(event, comm_event->task); 7909 7910 perf_output_put(&handle, comm_event->event_id); 7911 __output_copy(&handle, comm_event->comm, 7912 comm_event->comm_size); 7913 7914 perf_event__output_id_sample(event, &handle, &sample); 7915 7916 perf_output_end(&handle); 7917 out: 7918 comm_event->event_id.header.size = size; 7919 } 7920 7921 static void perf_event_comm_event(struct perf_comm_event *comm_event) 7922 { 7923 char comm[TASK_COMM_LEN]; 7924 unsigned int size; 7925 7926 memset(comm, 0, sizeof(comm)); 7927 strlcpy(comm, comm_event->task->comm, sizeof(comm)); 7928 size = ALIGN(strlen(comm)+1, sizeof(u64)); 7929 7930 comm_event->comm = comm; 7931 comm_event->comm_size = size; 7932 7933 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size; 7934 7935 perf_iterate_sb(perf_event_comm_output, 7936 comm_event, 7937 NULL); 7938 } 7939 7940 void perf_event_comm(struct task_struct *task, bool exec) 7941 { 7942 struct perf_comm_event comm_event; 7943 7944 if (!atomic_read(&nr_comm_events)) 7945 return; 7946 7947 comm_event = (struct perf_comm_event){ 7948 .task = task, 7949 /* .comm */ 7950 /* .comm_size */ 7951 .event_id = { 7952 .header = { 7953 .type = PERF_RECORD_COMM, 7954 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0, 7955 /* .size */ 7956 }, 7957 /* .pid */ 7958 /* .tid */ 7959 }, 7960 }; 7961 7962 perf_event_comm_event(&comm_event); 7963 } 7964 7965 /* 7966 * namespaces tracking 7967 */ 7968 7969 struct perf_namespaces_event { 7970 struct task_struct *task; 7971 7972 struct { 7973 struct perf_event_header header; 7974 7975 u32 pid; 7976 u32 tid; 7977 u64 nr_namespaces; 7978 struct perf_ns_link_info link_info[NR_NAMESPACES]; 7979 } event_id; 7980 }; 7981 7982 static int perf_event_namespaces_match(struct perf_event *event) 7983 { 7984 return event->attr.namespaces; 7985 } 7986 7987 static void perf_event_namespaces_output(struct perf_event *event, 7988 void *data) 7989 { 7990 struct perf_namespaces_event *namespaces_event = data; 7991 struct perf_output_handle handle; 7992 struct perf_sample_data sample; 7993 u16 header_size = namespaces_event->event_id.header.size; 7994 int ret; 7995 7996 if (!perf_event_namespaces_match(event)) 7997 return; 7998 7999 perf_event_header__init_id(&namespaces_event->event_id.header, 8000 &sample, event); 8001 ret = perf_output_begin(&handle, &sample, event, 8002 namespaces_event->event_id.header.size); 8003 if (ret) 8004 goto out; 8005 8006 namespaces_event->event_id.pid = perf_event_pid(event, 8007 namespaces_event->task); 8008 namespaces_event->event_id.tid = perf_event_tid(event, 8009 namespaces_event->task); 8010 8011 perf_output_put(&handle, namespaces_event->event_id); 8012 8013 perf_event__output_id_sample(event, &handle, &sample); 8014 8015 perf_output_end(&handle); 8016 out: 8017 namespaces_event->event_id.header.size = header_size; 8018 } 8019 8020 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info, 8021 struct task_struct *task, 8022 const struct proc_ns_operations *ns_ops) 8023 { 8024 struct path ns_path; 8025 struct inode *ns_inode; 8026 int error; 8027 8028 error = ns_get_path(&ns_path, task, ns_ops); 8029 if (!error) { 8030 ns_inode = ns_path.dentry->d_inode; 8031 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev); 8032 ns_link_info->ino = ns_inode->i_ino; 8033 path_put(&ns_path); 8034 } 8035 } 8036 8037 void perf_event_namespaces(struct task_struct *task) 8038 { 8039 struct perf_namespaces_event namespaces_event; 8040 struct perf_ns_link_info *ns_link_info; 8041 8042 if (!atomic_read(&nr_namespaces_events)) 8043 return; 8044 8045 namespaces_event = (struct perf_namespaces_event){ 8046 .task = task, 8047 .event_id = { 8048 .header = { 8049 .type = PERF_RECORD_NAMESPACES, 8050 .misc = 0, 8051 .size = sizeof(namespaces_event.event_id), 8052 }, 8053 /* .pid */ 8054 /* .tid */ 8055 .nr_namespaces = NR_NAMESPACES, 8056 /* .link_info[NR_NAMESPACES] */ 8057 }, 8058 }; 8059 8060 ns_link_info = namespaces_event.event_id.link_info; 8061 8062 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX], 8063 task, &mntns_operations); 8064 8065 #ifdef CONFIG_USER_NS 8066 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX], 8067 task, &userns_operations); 8068 #endif 8069 #ifdef CONFIG_NET_NS 8070 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX], 8071 task, &netns_operations); 8072 #endif 8073 #ifdef CONFIG_UTS_NS 8074 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX], 8075 task, &utsns_operations); 8076 #endif 8077 #ifdef CONFIG_IPC_NS 8078 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX], 8079 task, &ipcns_operations); 8080 #endif 8081 #ifdef CONFIG_PID_NS 8082 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX], 8083 task, &pidns_operations); 8084 #endif 8085 #ifdef CONFIG_CGROUPS 8086 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX], 8087 task, &cgroupns_operations); 8088 #endif 8089 8090 perf_iterate_sb(perf_event_namespaces_output, 8091 &namespaces_event, 8092 NULL); 8093 } 8094 8095 /* 8096 * cgroup tracking 8097 */ 8098 #ifdef CONFIG_CGROUP_PERF 8099 8100 struct perf_cgroup_event { 8101 char *path; 8102 int path_size; 8103 struct { 8104 struct perf_event_header header; 8105 u64 id; 8106 char path[]; 8107 } event_id; 8108 }; 8109 8110 static int perf_event_cgroup_match(struct perf_event *event) 8111 { 8112 return event->attr.cgroup; 8113 } 8114 8115 static void perf_event_cgroup_output(struct perf_event *event, void *data) 8116 { 8117 struct perf_cgroup_event *cgroup_event = data; 8118 struct perf_output_handle handle; 8119 struct perf_sample_data sample; 8120 u16 header_size = cgroup_event->event_id.header.size; 8121 int ret; 8122 8123 if (!perf_event_cgroup_match(event)) 8124 return; 8125 8126 perf_event_header__init_id(&cgroup_event->event_id.header, 8127 &sample, event); 8128 ret = perf_output_begin(&handle, &sample, event, 8129 cgroup_event->event_id.header.size); 8130 if (ret) 8131 goto out; 8132 8133 perf_output_put(&handle, cgroup_event->event_id); 8134 __output_copy(&handle, cgroup_event->path, cgroup_event->path_size); 8135 8136 perf_event__output_id_sample(event, &handle, &sample); 8137 8138 perf_output_end(&handle); 8139 out: 8140 cgroup_event->event_id.header.size = header_size; 8141 } 8142 8143 static void perf_event_cgroup(struct cgroup *cgrp) 8144 { 8145 struct perf_cgroup_event cgroup_event; 8146 char path_enomem[16] = "//enomem"; 8147 char *pathname; 8148 size_t size; 8149 8150 if (!atomic_read(&nr_cgroup_events)) 8151 return; 8152 8153 cgroup_event = (struct perf_cgroup_event){ 8154 .event_id = { 8155 .header = { 8156 .type = PERF_RECORD_CGROUP, 8157 .misc = 0, 8158 .size = sizeof(cgroup_event.event_id), 8159 }, 8160 .id = cgroup_id(cgrp), 8161 }, 8162 }; 8163 8164 pathname = kmalloc(PATH_MAX, GFP_KERNEL); 8165 if (pathname == NULL) { 8166 cgroup_event.path = path_enomem; 8167 } else { 8168 /* just to be sure to have enough space for alignment */ 8169 cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64)); 8170 cgroup_event.path = pathname; 8171 } 8172 8173 /* 8174 * Since our buffer works in 8 byte units we need to align our string 8175 * size to a multiple of 8. However, we must guarantee the tail end is 8176 * zero'd out to avoid leaking random bits to userspace. 8177 */ 8178 size = strlen(cgroup_event.path) + 1; 8179 while (!IS_ALIGNED(size, sizeof(u64))) 8180 cgroup_event.path[size++] = '\0'; 8181 8182 cgroup_event.event_id.header.size += size; 8183 cgroup_event.path_size = size; 8184 8185 perf_iterate_sb(perf_event_cgroup_output, 8186 &cgroup_event, 8187 NULL); 8188 8189 kfree(pathname); 8190 } 8191 8192 #endif 8193 8194 /* 8195 * mmap tracking 8196 */ 8197 8198 struct perf_mmap_event { 8199 struct vm_area_struct *vma; 8200 8201 const char *file_name; 8202 int file_size; 8203 int maj, min; 8204 u64 ino; 8205 u64 ino_generation; 8206 u32 prot, flags; 8207 u8 build_id[BUILD_ID_SIZE_MAX]; 8208 u32 build_id_size; 8209 8210 struct { 8211 struct perf_event_header header; 8212 8213 u32 pid; 8214 u32 tid; 8215 u64 start; 8216 u64 len; 8217 u64 pgoff; 8218 } event_id; 8219 }; 8220 8221 static int perf_event_mmap_match(struct perf_event *event, 8222 void *data) 8223 { 8224 struct perf_mmap_event *mmap_event = data; 8225 struct vm_area_struct *vma = mmap_event->vma; 8226 int executable = vma->vm_flags & VM_EXEC; 8227 8228 return (!executable && event->attr.mmap_data) || 8229 (executable && (event->attr.mmap || event->attr.mmap2)); 8230 } 8231 8232 static void perf_event_mmap_output(struct perf_event *event, 8233 void *data) 8234 { 8235 struct perf_mmap_event *mmap_event = data; 8236 struct perf_output_handle handle; 8237 struct perf_sample_data sample; 8238 int size = mmap_event->event_id.header.size; 8239 u32 type = mmap_event->event_id.header.type; 8240 bool use_build_id; 8241 int ret; 8242 8243 if (!perf_event_mmap_match(event, data)) 8244 return; 8245 8246 if (event->attr.mmap2) { 8247 mmap_event->event_id.header.type = PERF_RECORD_MMAP2; 8248 mmap_event->event_id.header.size += sizeof(mmap_event->maj); 8249 mmap_event->event_id.header.size += sizeof(mmap_event->min); 8250 mmap_event->event_id.header.size += sizeof(mmap_event->ino); 8251 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation); 8252 mmap_event->event_id.header.size += sizeof(mmap_event->prot); 8253 mmap_event->event_id.header.size += sizeof(mmap_event->flags); 8254 } 8255 8256 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event); 8257 ret = perf_output_begin(&handle, &sample, event, 8258 mmap_event->event_id.header.size); 8259 if (ret) 8260 goto out; 8261 8262 mmap_event->event_id.pid = perf_event_pid(event, current); 8263 mmap_event->event_id.tid = perf_event_tid(event, current); 8264 8265 use_build_id = event->attr.build_id && mmap_event->build_id_size; 8266 8267 if (event->attr.mmap2 && use_build_id) 8268 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID; 8269 8270 perf_output_put(&handle, mmap_event->event_id); 8271 8272 if (event->attr.mmap2) { 8273 if (use_build_id) { 8274 u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 }; 8275 8276 __output_copy(&handle, size, 4); 8277 __output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX); 8278 } else { 8279 perf_output_put(&handle, mmap_event->maj); 8280 perf_output_put(&handle, mmap_event->min); 8281 perf_output_put(&handle, mmap_event->ino); 8282 perf_output_put(&handle, mmap_event->ino_generation); 8283 } 8284 perf_output_put(&handle, mmap_event->prot); 8285 perf_output_put(&handle, mmap_event->flags); 8286 } 8287 8288 __output_copy(&handle, mmap_event->file_name, 8289 mmap_event->file_size); 8290 8291 perf_event__output_id_sample(event, &handle, &sample); 8292 8293 perf_output_end(&handle); 8294 out: 8295 mmap_event->event_id.header.size = size; 8296 mmap_event->event_id.header.type = type; 8297 } 8298 8299 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) 8300 { 8301 struct vm_area_struct *vma = mmap_event->vma; 8302 struct file *file = vma->vm_file; 8303 int maj = 0, min = 0; 8304 u64 ino = 0, gen = 0; 8305 u32 prot = 0, flags = 0; 8306 unsigned int size; 8307 char tmp[16]; 8308 char *buf = NULL; 8309 char *name; 8310 8311 if (vma->vm_flags & VM_READ) 8312 prot |= PROT_READ; 8313 if (vma->vm_flags & VM_WRITE) 8314 prot |= PROT_WRITE; 8315 if (vma->vm_flags & VM_EXEC) 8316 prot |= PROT_EXEC; 8317 8318 if (vma->vm_flags & VM_MAYSHARE) 8319 flags = MAP_SHARED; 8320 else 8321 flags = MAP_PRIVATE; 8322 8323 if (vma->vm_flags & VM_LOCKED) 8324 flags |= MAP_LOCKED; 8325 if (is_vm_hugetlb_page(vma)) 8326 flags |= MAP_HUGETLB; 8327 8328 if (file) { 8329 struct inode *inode; 8330 dev_t dev; 8331 8332 buf = kmalloc(PATH_MAX, GFP_KERNEL); 8333 if (!buf) { 8334 name = "//enomem"; 8335 goto cpy_name; 8336 } 8337 /* 8338 * d_path() works from the end of the rb backwards, so we 8339 * need to add enough zero bytes after the string to handle 8340 * the 64bit alignment we do later. 8341 */ 8342 name = file_path(file, buf, PATH_MAX - sizeof(u64)); 8343 if (IS_ERR(name)) { 8344 name = "//toolong"; 8345 goto cpy_name; 8346 } 8347 inode = file_inode(vma->vm_file); 8348 dev = inode->i_sb->s_dev; 8349 ino = inode->i_ino; 8350 gen = inode->i_generation; 8351 maj = MAJOR(dev); 8352 min = MINOR(dev); 8353 8354 goto got_name; 8355 } else { 8356 if (vma->vm_ops && vma->vm_ops->name) { 8357 name = (char *) vma->vm_ops->name(vma); 8358 if (name) 8359 goto cpy_name; 8360 } 8361 8362 name = (char *)arch_vma_name(vma); 8363 if (name) 8364 goto cpy_name; 8365 8366 if (vma->vm_start <= vma->vm_mm->start_brk && 8367 vma->vm_end >= vma->vm_mm->brk) { 8368 name = "[heap]"; 8369 goto cpy_name; 8370 } 8371 if (vma->vm_start <= vma->vm_mm->start_stack && 8372 vma->vm_end >= vma->vm_mm->start_stack) { 8373 name = "[stack]"; 8374 goto cpy_name; 8375 } 8376 8377 name = "//anon"; 8378 goto cpy_name; 8379 } 8380 8381 cpy_name: 8382 strlcpy(tmp, name, sizeof(tmp)); 8383 name = tmp; 8384 got_name: 8385 /* 8386 * Since our buffer works in 8 byte units we need to align our string 8387 * size to a multiple of 8. However, we must guarantee the tail end is 8388 * zero'd out to avoid leaking random bits to userspace. 8389 */ 8390 size = strlen(name)+1; 8391 while (!IS_ALIGNED(size, sizeof(u64))) 8392 name[size++] = '\0'; 8393 8394 mmap_event->file_name = name; 8395 mmap_event->file_size = size; 8396 mmap_event->maj = maj; 8397 mmap_event->min = min; 8398 mmap_event->ino = ino; 8399 mmap_event->ino_generation = gen; 8400 mmap_event->prot = prot; 8401 mmap_event->flags = flags; 8402 8403 if (!(vma->vm_flags & VM_EXEC)) 8404 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA; 8405 8406 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size; 8407 8408 if (atomic_read(&nr_build_id_events)) 8409 build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size); 8410 8411 perf_iterate_sb(perf_event_mmap_output, 8412 mmap_event, 8413 NULL); 8414 8415 kfree(buf); 8416 } 8417 8418 /* 8419 * Check whether inode and address range match filter criteria. 8420 */ 8421 static bool perf_addr_filter_match(struct perf_addr_filter *filter, 8422 struct file *file, unsigned long offset, 8423 unsigned long size) 8424 { 8425 /* d_inode(NULL) won't be equal to any mapped user-space file */ 8426 if (!filter->path.dentry) 8427 return false; 8428 8429 if (d_inode(filter->path.dentry) != file_inode(file)) 8430 return false; 8431 8432 if (filter->offset > offset + size) 8433 return false; 8434 8435 if (filter->offset + filter->size < offset) 8436 return false; 8437 8438 return true; 8439 } 8440 8441 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter, 8442 struct vm_area_struct *vma, 8443 struct perf_addr_filter_range *fr) 8444 { 8445 unsigned long vma_size = vma->vm_end - vma->vm_start; 8446 unsigned long off = vma->vm_pgoff << PAGE_SHIFT; 8447 struct file *file = vma->vm_file; 8448 8449 if (!perf_addr_filter_match(filter, file, off, vma_size)) 8450 return false; 8451 8452 if (filter->offset < off) { 8453 fr->start = vma->vm_start; 8454 fr->size = min(vma_size, filter->size - (off - filter->offset)); 8455 } else { 8456 fr->start = vma->vm_start + filter->offset - off; 8457 fr->size = min(vma->vm_end - fr->start, filter->size); 8458 } 8459 8460 return true; 8461 } 8462 8463 static void __perf_addr_filters_adjust(struct perf_event *event, void *data) 8464 { 8465 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 8466 struct vm_area_struct *vma = data; 8467 struct perf_addr_filter *filter; 8468 unsigned int restart = 0, count = 0; 8469 unsigned long flags; 8470 8471 if (!has_addr_filter(event)) 8472 return; 8473 8474 if (!vma->vm_file) 8475 return; 8476 8477 raw_spin_lock_irqsave(&ifh->lock, flags); 8478 list_for_each_entry(filter, &ifh->list, entry) { 8479 if (perf_addr_filter_vma_adjust(filter, vma, 8480 &event->addr_filter_ranges[count])) 8481 restart++; 8482 8483 count++; 8484 } 8485 8486 if (restart) 8487 event->addr_filters_gen++; 8488 raw_spin_unlock_irqrestore(&ifh->lock, flags); 8489 8490 if (restart) 8491 perf_event_stop(event, 1); 8492 } 8493 8494 /* 8495 * Adjust all task's events' filters to the new vma 8496 */ 8497 static void perf_addr_filters_adjust(struct vm_area_struct *vma) 8498 { 8499 struct perf_event_context *ctx; 8500 int ctxn; 8501 8502 /* 8503 * Data tracing isn't supported yet and as such there is no need 8504 * to keep track of anything that isn't related to executable code: 8505 */ 8506 if (!(vma->vm_flags & VM_EXEC)) 8507 return; 8508 8509 rcu_read_lock(); 8510 for_each_task_context_nr(ctxn) { 8511 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); 8512 if (!ctx) 8513 continue; 8514 8515 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true); 8516 } 8517 rcu_read_unlock(); 8518 } 8519 8520 void perf_event_mmap(struct vm_area_struct *vma) 8521 { 8522 struct perf_mmap_event mmap_event; 8523 8524 if (!atomic_read(&nr_mmap_events)) 8525 return; 8526 8527 mmap_event = (struct perf_mmap_event){ 8528 .vma = vma, 8529 /* .file_name */ 8530 /* .file_size */ 8531 .event_id = { 8532 .header = { 8533 .type = PERF_RECORD_MMAP, 8534 .misc = PERF_RECORD_MISC_USER, 8535 /* .size */ 8536 }, 8537 /* .pid */ 8538 /* .tid */ 8539 .start = vma->vm_start, 8540 .len = vma->vm_end - vma->vm_start, 8541 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT, 8542 }, 8543 /* .maj (attr_mmap2 only) */ 8544 /* .min (attr_mmap2 only) */ 8545 /* .ino (attr_mmap2 only) */ 8546 /* .ino_generation (attr_mmap2 only) */ 8547 /* .prot (attr_mmap2 only) */ 8548 /* .flags (attr_mmap2 only) */ 8549 }; 8550 8551 perf_addr_filters_adjust(vma); 8552 perf_event_mmap_event(&mmap_event); 8553 } 8554 8555 void perf_event_aux_event(struct perf_event *event, unsigned long head, 8556 unsigned long size, u64 flags) 8557 { 8558 struct perf_output_handle handle; 8559 struct perf_sample_data sample; 8560 struct perf_aux_event { 8561 struct perf_event_header header; 8562 u64 offset; 8563 u64 size; 8564 u64 flags; 8565 } rec = { 8566 .header = { 8567 .type = PERF_RECORD_AUX, 8568 .misc = 0, 8569 .size = sizeof(rec), 8570 }, 8571 .offset = head, 8572 .size = size, 8573 .flags = flags, 8574 }; 8575 int ret; 8576 8577 perf_event_header__init_id(&rec.header, &sample, event); 8578 ret = perf_output_begin(&handle, &sample, event, rec.header.size); 8579 8580 if (ret) 8581 return; 8582 8583 perf_output_put(&handle, rec); 8584 perf_event__output_id_sample(event, &handle, &sample); 8585 8586 perf_output_end(&handle); 8587 } 8588 8589 /* 8590 * Lost/dropped samples logging 8591 */ 8592 void perf_log_lost_samples(struct perf_event *event, u64 lost) 8593 { 8594 struct perf_output_handle handle; 8595 struct perf_sample_data sample; 8596 int ret; 8597 8598 struct { 8599 struct perf_event_header header; 8600 u64 lost; 8601 } lost_samples_event = { 8602 .header = { 8603 .type = PERF_RECORD_LOST_SAMPLES, 8604 .misc = 0, 8605 .size = sizeof(lost_samples_event), 8606 }, 8607 .lost = lost, 8608 }; 8609 8610 perf_event_header__init_id(&lost_samples_event.header, &sample, event); 8611 8612 ret = perf_output_begin(&handle, &sample, event, 8613 lost_samples_event.header.size); 8614 if (ret) 8615 return; 8616 8617 perf_output_put(&handle, lost_samples_event); 8618 perf_event__output_id_sample(event, &handle, &sample); 8619 perf_output_end(&handle); 8620 } 8621 8622 /* 8623 * context_switch tracking 8624 */ 8625 8626 struct perf_switch_event { 8627 struct task_struct *task; 8628 struct task_struct *next_prev; 8629 8630 struct { 8631 struct perf_event_header header; 8632 u32 next_prev_pid; 8633 u32 next_prev_tid; 8634 } event_id; 8635 }; 8636 8637 static int perf_event_switch_match(struct perf_event *event) 8638 { 8639 return event->attr.context_switch; 8640 } 8641 8642 static void perf_event_switch_output(struct perf_event *event, void *data) 8643 { 8644 struct perf_switch_event *se = data; 8645 struct perf_output_handle handle; 8646 struct perf_sample_data sample; 8647 int ret; 8648 8649 if (!perf_event_switch_match(event)) 8650 return; 8651 8652 /* Only CPU-wide events are allowed to see next/prev pid/tid */ 8653 if (event->ctx->task) { 8654 se->event_id.header.type = PERF_RECORD_SWITCH; 8655 se->event_id.header.size = sizeof(se->event_id.header); 8656 } else { 8657 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE; 8658 se->event_id.header.size = sizeof(se->event_id); 8659 se->event_id.next_prev_pid = 8660 perf_event_pid(event, se->next_prev); 8661 se->event_id.next_prev_tid = 8662 perf_event_tid(event, se->next_prev); 8663 } 8664 8665 perf_event_header__init_id(&se->event_id.header, &sample, event); 8666 8667 ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size); 8668 if (ret) 8669 return; 8670 8671 if (event->ctx->task) 8672 perf_output_put(&handle, se->event_id.header); 8673 else 8674 perf_output_put(&handle, se->event_id); 8675 8676 perf_event__output_id_sample(event, &handle, &sample); 8677 8678 perf_output_end(&handle); 8679 } 8680 8681 static void perf_event_switch(struct task_struct *task, 8682 struct task_struct *next_prev, bool sched_in) 8683 { 8684 struct perf_switch_event switch_event; 8685 8686 /* N.B. caller checks nr_switch_events != 0 */ 8687 8688 switch_event = (struct perf_switch_event){ 8689 .task = task, 8690 .next_prev = next_prev, 8691 .event_id = { 8692 .header = { 8693 /* .type */ 8694 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT, 8695 /* .size */ 8696 }, 8697 /* .next_prev_pid */ 8698 /* .next_prev_tid */ 8699 }, 8700 }; 8701 8702 if (!sched_in && task->on_rq) { 8703 switch_event.event_id.header.misc |= 8704 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT; 8705 } 8706 8707 perf_iterate_sb(perf_event_switch_output, &switch_event, NULL); 8708 } 8709 8710 /* 8711 * IRQ throttle logging 8712 */ 8713 8714 static void perf_log_throttle(struct perf_event *event, int enable) 8715 { 8716 struct perf_output_handle handle; 8717 struct perf_sample_data sample; 8718 int ret; 8719 8720 struct { 8721 struct perf_event_header header; 8722 u64 time; 8723 u64 id; 8724 u64 stream_id; 8725 } throttle_event = { 8726 .header = { 8727 .type = PERF_RECORD_THROTTLE, 8728 .misc = 0, 8729 .size = sizeof(throttle_event), 8730 }, 8731 .time = perf_event_clock(event), 8732 .id = primary_event_id(event), 8733 .stream_id = event->id, 8734 }; 8735 8736 if (enable) 8737 throttle_event.header.type = PERF_RECORD_UNTHROTTLE; 8738 8739 perf_event_header__init_id(&throttle_event.header, &sample, event); 8740 8741 ret = perf_output_begin(&handle, &sample, event, 8742 throttle_event.header.size); 8743 if (ret) 8744 return; 8745 8746 perf_output_put(&handle, throttle_event); 8747 perf_event__output_id_sample(event, &handle, &sample); 8748 perf_output_end(&handle); 8749 } 8750 8751 /* 8752 * ksymbol register/unregister tracking 8753 */ 8754 8755 struct perf_ksymbol_event { 8756 const char *name; 8757 int name_len; 8758 struct { 8759 struct perf_event_header header; 8760 u64 addr; 8761 u32 len; 8762 u16 ksym_type; 8763 u16 flags; 8764 } event_id; 8765 }; 8766 8767 static int perf_event_ksymbol_match(struct perf_event *event) 8768 { 8769 return event->attr.ksymbol; 8770 } 8771 8772 static void perf_event_ksymbol_output(struct perf_event *event, void *data) 8773 { 8774 struct perf_ksymbol_event *ksymbol_event = data; 8775 struct perf_output_handle handle; 8776 struct perf_sample_data sample; 8777 int ret; 8778 8779 if (!perf_event_ksymbol_match(event)) 8780 return; 8781 8782 perf_event_header__init_id(&ksymbol_event->event_id.header, 8783 &sample, event); 8784 ret = perf_output_begin(&handle, &sample, event, 8785 ksymbol_event->event_id.header.size); 8786 if (ret) 8787 return; 8788 8789 perf_output_put(&handle, ksymbol_event->event_id); 8790 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len); 8791 perf_event__output_id_sample(event, &handle, &sample); 8792 8793 perf_output_end(&handle); 8794 } 8795 8796 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister, 8797 const char *sym) 8798 { 8799 struct perf_ksymbol_event ksymbol_event; 8800 char name[KSYM_NAME_LEN]; 8801 u16 flags = 0; 8802 int name_len; 8803 8804 if (!atomic_read(&nr_ksymbol_events)) 8805 return; 8806 8807 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX || 8808 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN) 8809 goto err; 8810 8811 strlcpy(name, sym, KSYM_NAME_LEN); 8812 name_len = strlen(name) + 1; 8813 while (!IS_ALIGNED(name_len, sizeof(u64))) 8814 name[name_len++] = '\0'; 8815 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64)); 8816 8817 if (unregister) 8818 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER; 8819 8820 ksymbol_event = (struct perf_ksymbol_event){ 8821 .name = name, 8822 .name_len = name_len, 8823 .event_id = { 8824 .header = { 8825 .type = PERF_RECORD_KSYMBOL, 8826 .size = sizeof(ksymbol_event.event_id) + 8827 name_len, 8828 }, 8829 .addr = addr, 8830 .len = len, 8831 .ksym_type = ksym_type, 8832 .flags = flags, 8833 }, 8834 }; 8835 8836 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL); 8837 return; 8838 err: 8839 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type); 8840 } 8841 8842 /* 8843 * bpf program load/unload tracking 8844 */ 8845 8846 struct perf_bpf_event { 8847 struct bpf_prog *prog; 8848 struct { 8849 struct perf_event_header header; 8850 u16 type; 8851 u16 flags; 8852 u32 id; 8853 u8 tag[BPF_TAG_SIZE]; 8854 } event_id; 8855 }; 8856 8857 static int perf_event_bpf_match(struct perf_event *event) 8858 { 8859 return event->attr.bpf_event; 8860 } 8861 8862 static void perf_event_bpf_output(struct perf_event *event, void *data) 8863 { 8864 struct perf_bpf_event *bpf_event = data; 8865 struct perf_output_handle handle; 8866 struct perf_sample_data sample; 8867 int ret; 8868 8869 if (!perf_event_bpf_match(event)) 8870 return; 8871 8872 perf_event_header__init_id(&bpf_event->event_id.header, 8873 &sample, event); 8874 ret = perf_output_begin(&handle, data, event, 8875 bpf_event->event_id.header.size); 8876 if (ret) 8877 return; 8878 8879 perf_output_put(&handle, bpf_event->event_id); 8880 perf_event__output_id_sample(event, &handle, &sample); 8881 8882 perf_output_end(&handle); 8883 } 8884 8885 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog, 8886 enum perf_bpf_event_type type) 8887 { 8888 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD; 8889 int i; 8890 8891 if (prog->aux->func_cnt == 0) { 8892 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF, 8893 (u64)(unsigned long)prog->bpf_func, 8894 prog->jited_len, unregister, 8895 prog->aux->ksym.name); 8896 } else { 8897 for (i = 0; i < prog->aux->func_cnt; i++) { 8898 struct bpf_prog *subprog = prog->aux->func[i]; 8899 8900 perf_event_ksymbol( 8901 PERF_RECORD_KSYMBOL_TYPE_BPF, 8902 (u64)(unsigned long)subprog->bpf_func, 8903 subprog->jited_len, unregister, 8904 prog->aux->ksym.name); 8905 } 8906 } 8907 } 8908 8909 void perf_event_bpf_event(struct bpf_prog *prog, 8910 enum perf_bpf_event_type type, 8911 u16 flags) 8912 { 8913 struct perf_bpf_event bpf_event; 8914 8915 if (type <= PERF_BPF_EVENT_UNKNOWN || 8916 type >= PERF_BPF_EVENT_MAX) 8917 return; 8918 8919 switch (type) { 8920 case PERF_BPF_EVENT_PROG_LOAD: 8921 case PERF_BPF_EVENT_PROG_UNLOAD: 8922 if (atomic_read(&nr_ksymbol_events)) 8923 perf_event_bpf_emit_ksymbols(prog, type); 8924 break; 8925 default: 8926 break; 8927 } 8928 8929 if (!atomic_read(&nr_bpf_events)) 8930 return; 8931 8932 bpf_event = (struct perf_bpf_event){ 8933 .prog = prog, 8934 .event_id = { 8935 .header = { 8936 .type = PERF_RECORD_BPF_EVENT, 8937 .size = sizeof(bpf_event.event_id), 8938 }, 8939 .type = type, 8940 .flags = flags, 8941 .id = prog->aux->id, 8942 }, 8943 }; 8944 8945 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64)); 8946 8947 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE); 8948 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL); 8949 } 8950 8951 struct perf_text_poke_event { 8952 const void *old_bytes; 8953 const void *new_bytes; 8954 size_t pad; 8955 u16 old_len; 8956 u16 new_len; 8957 8958 struct { 8959 struct perf_event_header header; 8960 8961 u64 addr; 8962 } event_id; 8963 }; 8964 8965 static int perf_event_text_poke_match(struct perf_event *event) 8966 { 8967 return event->attr.text_poke; 8968 } 8969 8970 static void perf_event_text_poke_output(struct perf_event *event, void *data) 8971 { 8972 struct perf_text_poke_event *text_poke_event = data; 8973 struct perf_output_handle handle; 8974 struct perf_sample_data sample; 8975 u64 padding = 0; 8976 int ret; 8977 8978 if (!perf_event_text_poke_match(event)) 8979 return; 8980 8981 perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event); 8982 8983 ret = perf_output_begin(&handle, &sample, event, 8984 text_poke_event->event_id.header.size); 8985 if (ret) 8986 return; 8987 8988 perf_output_put(&handle, text_poke_event->event_id); 8989 perf_output_put(&handle, text_poke_event->old_len); 8990 perf_output_put(&handle, text_poke_event->new_len); 8991 8992 __output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len); 8993 __output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len); 8994 8995 if (text_poke_event->pad) 8996 __output_copy(&handle, &padding, text_poke_event->pad); 8997 8998 perf_event__output_id_sample(event, &handle, &sample); 8999 9000 perf_output_end(&handle); 9001 } 9002 9003 void perf_event_text_poke(const void *addr, const void *old_bytes, 9004 size_t old_len, const void *new_bytes, size_t new_len) 9005 { 9006 struct perf_text_poke_event text_poke_event; 9007 size_t tot, pad; 9008 9009 if (!atomic_read(&nr_text_poke_events)) 9010 return; 9011 9012 tot = sizeof(text_poke_event.old_len) + old_len; 9013 tot += sizeof(text_poke_event.new_len) + new_len; 9014 pad = ALIGN(tot, sizeof(u64)) - tot; 9015 9016 text_poke_event = (struct perf_text_poke_event){ 9017 .old_bytes = old_bytes, 9018 .new_bytes = new_bytes, 9019 .pad = pad, 9020 .old_len = old_len, 9021 .new_len = new_len, 9022 .event_id = { 9023 .header = { 9024 .type = PERF_RECORD_TEXT_POKE, 9025 .misc = PERF_RECORD_MISC_KERNEL, 9026 .size = sizeof(text_poke_event.event_id) + tot + pad, 9027 }, 9028 .addr = (unsigned long)addr, 9029 }, 9030 }; 9031 9032 perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL); 9033 } 9034 9035 void perf_event_itrace_started(struct perf_event *event) 9036 { 9037 event->attach_state |= PERF_ATTACH_ITRACE; 9038 } 9039 9040 static void perf_log_itrace_start(struct perf_event *event) 9041 { 9042 struct perf_output_handle handle; 9043 struct perf_sample_data sample; 9044 struct perf_aux_event { 9045 struct perf_event_header header; 9046 u32 pid; 9047 u32 tid; 9048 } rec; 9049 int ret; 9050 9051 if (event->parent) 9052 event = event->parent; 9053 9054 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) || 9055 event->attach_state & PERF_ATTACH_ITRACE) 9056 return; 9057 9058 rec.header.type = PERF_RECORD_ITRACE_START; 9059 rec.header.misc = 0; 9060 rec.header.size = sizeof(rec); 9061 rec.pid = perf_event_pid(event, current); 9062 rec.tid = perf_event_tid(event, current); 9063 9064 perf_event_header__init_id(&rec.header, &sample, event); 9065 ret = perf_output_begin(&handle, &sample, event, rec.header.size); 9066 9067 if (ret) 9068 return; 9069 9070 perf_output_put(&handle, rec); 9071 perf_event__output_id_sample(event, &handle, &sample); 9072 9073 perf_output_end(&handle); 9074 } 9075 9076 static int 9077 __perf_event_account_interrupt(struct perf_event *event, int throttle) 9078 { 9079 struct hw_perf_event *hwc = &event->hw; 9080 int ret = 0; 9081 u64 seq; 9082 9083 seq = __this_cpu_read(perf_throttled_seq); 9084 if (seq != hwc->interrupts_seq) { 9085 hwc->interrupts_seq = seq; 9086 hwc->interrupts = 1; 9087 } else { 9088 hwc->interrupts++; 9089 if (unlikely(throttle 9090 && hwc->interrupts >= max_samples_per_tick)) { 9091 __this_cpu_inc(perf_throttled_count); 9092 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); 9093 hwc->interrupts = MAX_INTERRUPTS; 9094 perf_log_throttle(event, 0); 9095 ret = 1; 9096 } 9097 } 9098 9099 if (event->attr.freq) { 9100 u64 now = perf_clock(); 9101 s64 delta = now - hwc->freq_time_stamp; 9102 9103 hwc->freq_time_stamp = now; 9104 9105 if (delta > 0 && delta < 2*TICK_NSEC) 9106 perf_adjust_period(event, delta, hwc->last_period, true); 9107 } 9108 9109 return ret; 9110 } 9111 9112 int perf_event_account_interrupt(struct perf_event *event) 9113 { 9114 return __perf_event_account_interrupt(event, 1); 9115 } 9116 9117 /* 9118 * Generic event overflow handling, sampling. 9119 */ 9120 9121 static int __perf_event_overflow(struct perf_event *event, 9122 int throttle, struct perf_sample_data *data, 9123 struct pt_regs *regs) 9124 { 9125 int events = atomic_read(&event->event_limit); 9126 int ret = 0; 9127 9128 /* 9129 * Non-sampling counters might still use the PMI to fold short 9130 * hardware counters, ignore those. 9131 */ 9132 if (unlikely(!is_sampling_event(event))) 9133 return 0; 9134 9135 ret = __perf_event_account_interrupt(event, throttle); 9136 9137 /* 9138 * XXX event_limit might not quite work as expected on inherited 9139 * events 9140 */ 9141 9142 event->pending_kill = POLL_IN; 9143 if (events && atomic_dec_and_test(&event->event_limit)) { 9144 ret = 1; 9145 event->pending_kill = POLL_HUP; 9146 event->pending_addr = data->addr; 9147 9148 perf_event_disable_inatomic(event); 9149 } 9150 9151 READ_ONCE(event->overflow_handler)(event, data, regs); 9152 9153 if (*perf_event_fasync(event) && event->pending_kill) { 9154 event->pending_wakeup = 1; 9155 irq_work_queue(&event->pending); 9156 } 9157 9158 return ret; 9159 } 9160 9161 int perf_event_overflow(struct perf_event *event, 9162 struct perf_sample_data *data, 9163 struct pt_regs *regs) 9164 { 9165 return __perf_event_overflow(event, 1, data, regs); 9166 } 9167 9168 /* 9169 * Generic software event infrastructure 9170 */ 9171 9172 struct swevent_htable { 9173 struct swevent_hlist *swevent_hlist; 9174 struct mutex hlist_mutex; 9175 int hlist_refcount; 9176 9177 /* Recursion avoidance in each contexts */ 9178 int recursion[PERF_NR_CONTEXTS]; 9179 }; 9180 9181 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable); 9182 9183 /* 9184 * We directly increment event->count and keep a second value in 9185 * event->hw.period_left to count intervals. This period event 9186 * is kept in the range [-sample_period, 0] so that we can use the 9187 * sign as trigger. 9188 */ 9189 9190 u64 perf_swevent_set_period(struct perf_event *event) 9191 { 9192 struct hw_perf_event *hwc = &event->hw; 9193 u64 period = hwc->last_period; 9194 u64 nr, offset; 9195 s64 old, val; 9196 9197 hwc->last_period = hwc->sample_period; 9198 9199 again: 9200 old = val = local64_read(&hwc->period_left); 9201 if (val < 0) 9202 return 0; 9203 9204 nr = div64_u64(period + val, period); 9205 offset = nr * period; 9206 val -= offset; 9207 if (local64_cmpxchg(&hwc->period_left, old, val) != old) 9208 goto again; 9209 9210 return nr; 9211 } 9212 9213 static void perf_swevent_overflow(struct perf_event *event, u64 overflow, 9214 struct perf_sample_data *data, 9215 struct pt_regs *regs) 9216 { 9217 struct hw_perf_event *hwc = &event->hw; 9218 int throttle = 0; 9219 9220 if (!overflow) 9221 overflow = perf_swevent_set_period(event); 9222 9223 if (hwc->interrupts == MAX_INTERRUPTS) 9224 return; 9225 9226 for (; overflow; overflow--) { 9227 if (__perf_event_overflow(event, throttle, 9228 data, regs)) { 9229 /* 9230 * We inhibit the overflow from happening when 9231 * hwc->interrupts == MAX_INTERRUPTS. 9232 */ 9233 break; 9234 } 9235 throttle = 1; 9236 } 9237 } 9238 9239 static void perf_swevent_event(struct perf_event *event, u64 nr, 9240 struct perf_sample_data *data, 9241 struct pt_regs *regs) 9242 { 9243 struct hw_perf_event *hwc = &event->hw; 9244 9245 local64_add(nr, &event->count); 9246 9247 if (!regs) 9248 return; 9249 9250 if (!is_sampling_event(event)) 9251 return; 9252 9253 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) { 9254 data->period = nr; 9255 return perf_swevent_overflow(event, 1, data, regs); 9256 } else 9257 data->period = event->hw.last_period; 9258 9259 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq) 9260 return perf_swevent_overflow(event, 1, data, regs); 9261 9262 if (local64_add_negative(nr, &hwc->period_left)) 9263 return; 9264 9265 perf_swevent_overflow(event, 0, data, regs); 9266 } 9267 9268 static int perf_exclude_event(struct perf_event *event, 9269 struct pt_regs *regs) 9270 { 9271 if (event->hw.state & PERF_HES_STOPPED) 9272 return 1; 9273 9274 if (regs) { 9275 if (event->attr.exclude_user && user_mode(regs)) 9276 return 1; 9277 9278 if (event->attr.exclude_kernel && !user_mode(regs)) 9279 return 1; 9280 } 9281 9282 return 0; 9283 } 9284 9285 static int perf_swevent_match(struct perf_event *event, 9286 enum perf_type_id type, 9287 u32 event_id, 9288 struct perf_sample_data *data, 9289 struct pt_regs *regs) 9290 { 9291 if (event->attr.type != type) 9292 return 0; 9293 9294 if (event->attr.config != event_id) 9295 return 0; 9296 9297 if (perf_exclude_event(event, regs)) 9298 return 0; 9299 9300 return 1; 9301 } 9302 9303 static inline u64 swevent_hash(u64 type, u32 event_id) 9304 { 9305 u64 val = event_id | (type << 32); 9306 9307 return hash_64(val, SWEVENT_HLIST_BITS); 9308 } 9309 9310 static inline struct hlist_head * 9311 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id) 9312 { 9313 u64 hash = swevent_hash(type, event_id); 9314 9315 return &hlist->heads[hash]; 9316 } 9317 9318 /* For the read side: events when they trigger */ 9319 static inline struct hlist_head * 9320 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id) 9321 { 9322 struct swevent_hlist *hlist; 9323 9324 hlist = rcu_dereference(swhash->swevent_hlist); 9325 if (!hlist) 9326 return NULL; 9327 9328 return __find_swevent_head(hlist, type, event_id); 9329 } 9330 9331 /* For the event head insertion and removal in the hlist */ 9332 static inline struct hlist_head * 9333 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event) 9334 { 9335 struct swevent_hlist *hlist; 9336 u32 event_id = event->attr.config; 9337 u64 type = event->attr.type; 9338 9339 /* 9340 * Event scheduling is always serialized against hlist allocation 9341 * and release. Which makes the protected version suitable here. 9342 * The context lock guarantees that. 9343 */ 9344 hlist = rcu_dereference_protected(swhash->swevent_hlist, 9345 lockdep_is_held(&event->ctx->lock)); 9346 if (!hlist) 9347 return NULL; 9348 9349 return __find_swevent_head(hlist, type, event_id); 9350 } 9351 9352 static void do_perf_sw_event(enum perf_type_id type, u32 event_id, 9353 u64 nr, 9354 struct perf_sample_data *data, 9355 struct pt_regs *regs) 9356 { 9357 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 9358 struct perf_event *event; 9359 struct hlist_head *head; 9360 9361 rcu_read_lock(); 9362 head = find_swevent_head_rcu(swhash, type, event_id); 9363 if (!head) 9364 goto end; 9365 9366 hlist_for_each_entry_rcu(event, head, hlist_entry) { 9367 if (perf_swevent_match(event, type, event_id, data, regs)) 9368 perf_swevent_event(event, nr, data, regs); 9369 } 9370 end: 9371 rcu_read_unlock(); 9372 } 9373 9374 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]); 9375 9376 int perf_swevent_get_recursion_context(void) 9377 { 9378 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 9379 9380 return get_recursion_context(swhash->recursion); 9381 } 9382 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context); 9383 9384 void perf_swevent_put_recursion_context(int rctx) 9385 { 9386 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 9387 9388 put_recursion_context(swhash->recursion, rctx); 9389 } 9390 9391 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) 9392 { 9393 struct perf_sample_data data; 9394 9395 if (WARN_ON_ONCE(!regs)) 9396 return; 9397 9398 perf_sample_data_init(&data, addr, 0); 9399 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs); 9400 } 9401 9402 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) 9403 { 9404 int rctx; 9405 9406 preempt_disable_notrace(); 9407 rctx = perf_swevent_get_recursion_context(); 9408 if (unlikely(rctx < 0)) 9409 goto fail; 9410 9411 ___perf_sw_event(event_id, nr, regs, addr); 9412 9413 perf_swevent_put_recursion_context(rctx); 9414 fail: 9415 preempt_enable_notrace(); 9416 } 9417 9418 static void perf_swevent_read(struct perf_event *event) 9419 { 9420 } 9421 9422 static int perf_swevent_add(struct perf_event *event, int flags) 9423 { 9424 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 9425 struct hw_perf_event *hwc = &event->hw; 9426 struct hlist_head *head; 9427 9428 if (is_sampling_event(event)) { 9429 hwc->last_period = hwc->sample_period; 9430 perf_swevent_set_period(event); 9431 } 9432 9433 hwc->state = !(flags & PERF_EF_START); 9434 9435 head = find_swevent_head(swhash, event); 9436 if (WARN_ON_ONCE(!head)) 9437 return -EINVAL; 9438 9439 hlist_add_head_rcu(&event->hlist_entry, head); 9440 perf_event_update_userpage(event); 9441 9442 return 0; 9443 } 9444 9445 static void perf_swevent_del(struct perf_event *event, int flags) 9446 { 9447 hlist_del_rcu(&event->hlist_entry); 9448 } 9449 9450 static void perf_swevent_start(struct perf_event *event, int flags) 9451 { 9452 event->hw.state = 0; 9453 } 9454 9455 static void perf_swevent_stop(struct perf_event *event, int flags) 9456 { 9457 event->hw.state = PERF_HES_STOPPED; 9458 } 9459 9460 /* Deref the hlist from the update side */ 9461 static inline struct swevent_hlist * 9462 swevent_hlist_deref(struct swevent_htable *swhash) 9463 { 9464 return rcu_dereference_protected(swhash->swevent_hlist, 9465 lockdep_is_held(&swhash->hlist_mutex)); 9466 } 9467 9468 static void swevent_hlist_release(struct swevent_htable *swhash) 9469 { 9470 struct swevent_hlist *hlist = swevent_hlist_deref(swhash); 9471 9472 if (!hlist) 9473 return; 9474 9475 RCU_INIT_POINTER(swhash->swevent_hlist, NULL); 9476 kfree_rcu(hlist, rcu_head); 9477 } 9478 9479 static void swevent_hlist_put_cpu(int cpu) 9480 { 9481 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 9482 9483 mutex_lock(&swhash->hlist_mutex); 9484 9485 if (!--swhash->hlist_refcount) 9486 swevent_hlist_release(swhash); 9487 9488 mutex_unlock(&swhash->hlist_mutex); 9489 } 9490 9491 static void swevent_hlist_put(void) 9492 { 9493 int cpu; 9494 9495 for_each_possible_cpu(cpu) 9496 swevent_hlist_put_cpu(cpu); 9497 } 9498 9499 static int swevent_hlist_get_cpu(int cpu) 9500 { 9501 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 9502 int err = 0; 9503 9504 mutex_lock(&swhash->hlist_mutex); 9505 if (!swevent_hlist_deref(swhash) && 9506 cpumask_test_cpu(cpu, perf_online_mask)) { 9507 struct swevent_hlist *hlist; 9508 9509 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL); 9510 if (!hlist) { 9511 err = -ENOMEM; 9512 goto exit; 9513 } 9514 rcu_assign_pointer(swhash->swevent_hlist, hlist); 9515 } 9516 swhash->hlist_refcount++; 9517 exit: 9518 mutex_unlock(&swhash->hlist_mutex); 9519 9520 return err; 9521 } 9522 9523 static int swevent_hlist_get(void) 9524 { 9525 int err, cpu, failed_cpu; 9526 9527 mutex_lock(&pmus_lock); 9528 for_each_possible_cpu(cpu) { 9529 err = swevent_hlist_get_cpu(cpu); 9530 if (err) { 9531 failed_cpu = cpu; 9532 goto fail; 9533 } 9534 } 9535 mutex_unlock(&pmus_lock); 9536 return 0; 9537 fail: 9538 for_each_possible_cpu(cpu) { 9539 if (cpu == failed_cpu) 9540 break; 9541 swevent_hlist_put_cpu(cpu); 9542 } 9543 mutex_unlock(&pmus_lock); 9544 return err; 9545 } 9546 9547 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX]; 9548 9549 static void sw_perf_event_destroy(struct perf_event *event) 9550 { 9551 u64 event_id = event->attr.config; 9552 9553 WARN_ON(event->parent); 9554 9555 static_key_slow_dec(&perf_swevent_enabled[event_id]); 9556 swevent_hlist_put(); 9557 } 9558 9559 static int perf_swevent_init(struct perf_event *event) 9560 { 9561 u64 event_id = event->attr.config; 9562 9563 if (event->attr.type != PERF_TYPE_SOFTWARE) 9564 return -ENOENT; 9565 9566 /* 9567 * no branch sampling for software events 9568 */ 9569 if (has_branch_stack(event)) 9570 return -EOPNOTSUPP; 9571 9572 switch (event_id) { 9573 case PERF_COUNT_SW_CPU_CLOCK: 9574 case PERF_COUNT_SW_TASK_CLOCK: 9575 return -ENOENT; 9576 9577 default: 9578 break; 9579 } 9580 9581 if (event_id >= PERF_COUNT_SW_MAX) 9582 return -ENOENT; 9583 9584 if (!event->parent) { 9585 int err; 9586 9587 err = swevent_hlist_get(); 9588 if (err) 9589 return err; 9590 9591 static_key_slow_inc(&perf_swevent_enabled[event_id]); 9592 event->destroy = sw_perf_event_destroy; 9593 } 9594 9595 return 0; 9596 } 9597 9598 static struct pmu perf_swevent = { 9599 .task_ctx_nr = perf_sw_context, 9600 9601 .capabilities = PERF_PMU_CAP_NO_NMI, 9602 9603 .event_init = perf_swevent_init, 9604 .add = perf_swevent_add, 9605 .del = perf_swevent_del, 9606 .start = perf_swevent_start, 9607 .stop = perf_swevent_stop, 9608 .read = perf_swevent_read, 9609 }; 9610 9611 #ifdef CONFIG_EVENT_TRACING 9612 9613 static int perf_tp_filter_match(struct perf_event *event, 9614 struct perf_sample_data *data) 9615 { 9616 void *record = data->raw->frag.data; 9617 9618 /* only top level events have filters set */ 9619 if (event->parent) 9620 event = event->parent; 9621 9622 if (likely(!event->filter) || filter_match_preds(event->filter, record)) 9623 return 1; 9624 return 0; 9625 } 9626 9627 static int perf_tp_event_match(struct perf_event *event, 9628 struct perf_sample_data *data, 9629 struct pt_regs *regs) 9630 { 9631 if (event->hw.state & PERF_HES_STOPPED) 9632 return 0; 9633 /* 9634 * If exclude_kernel, only trace user-space tracepoints (uprobes) 9635 */ 9636 if (event->attr.exclude_kernel && !user_mode(regs)) 9637 return 0; 9638 9639 if (!perf_tp_filter_match(event, data)) 9640 return 0; 9641 9642 return 1; 9643 } 9644 9645 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx, 9646 struct trace_event_call *call, u64 count, 9647 struct pt_regs *regs, struct hlist_head *head, 9648 struct task_struct *task) 9649 { 9650 if (bpf_prog_array_valid(call)) { 9651 *(struct pt_regs **)raw_data = regs; 9652 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) { 9653 perf_swevent_put_recursion_context(rctx); 9654 return; 9655 } 9656 } 9657 perf_tp_event(call->event.type, count, raw_data, size, regs, head, 9658 rctx, task); 9659 } 9660 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit); 9661 9662 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size, 9663 struct pt_regs *regs, struct hlist_head *head, int rctx, 9664 struct task_struct *task) 9665 { 9666 struct perf_sample_data data; 9667 struct perf_event *event; 9668 9669 struct perf_raw_record raw = { 9670 .frag = { 9671 .size = entry_size, 9672 .data = record, 9673 }, 9674 }; 9675 9676 perf_sample_data_init(&data, 0, 0); 9677 data.raw = &raw; 9678 9679 perf_trace_buf_update(record, event_type); 9680 9681 hlist_for_each_entry_rcu(event, head, hlist_entry) { 9682 if (perf_tp_event_match(event, &data, regs)) 9683 perf_swevent_event(event, count, &data, regs); 9684 } 9685 9686 /* 9687 * If we got specified a target task, also iterate its context and 9688 * deliver this event there too. 9689 */ 9690 if (task && task != current) { 9691 struct perf_event_context *ctx; 9692 struct trace_entry *entry = record; 9693 9694 rcu_read_lock(); 9695 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]); 9696 if (!ctx) 9697 goto unlock; 9698 9699 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 9700 if (event->cpu != smp_processor_id()) 9701 continue; 9702 if (event->attr.type != PERF_TYPE_TRACEPOINT) 9703 continue; 9704 if (event->attr.config != entry->type) 9705 continue; 9706 if (perf_tp_event_match(event, &data, regs)) 9707 perf_swevent_event(event, count, &data, regs); 9708 } 9709 unlock: 9710 rcu_read_unlock(); 9711 } 9712 9713 perf_swevent_put_recursion_context(rctx); 9714 } 9715 EXPORT_SYMBOL_GPL(perf_tp_event); 9716 9717 static void tp_perf_event_destroy(struct perf_event *event) 9718 { 9719 perf_trace_destroy(event); 9720 } 9721 9722 static int perf_tp_event_init(struct perf_event *event) 9723 { 9724 int err; 9725 9726 if (event->attr.type != PERF_TYPE_TRACEPOINT) 9727 return -ENOENT; 9728 9729 /* 9730 * no branch sampling for tracepoint events 9731 */ 9732 if (has_branch_stack(event)) 9733 return -EOPNOTSUPP; 9734 9735 err = perf_trace_init(event); 9736 if (err) 9737 return err; 9738 9739 event->destroy = tp_perf_event_destroy; 9740 9741 return 0; 9742 } 9743 9744 static struct pmu perf_tracepoint = { 9745 .task_ctx_nr = perf_sw_context, 9746 9747 .event_init = perf_tp_event_init, 9748 .add = perf_trace_add, 9749 .del = perf_trace_del, 9750 .start = perf_swevent_start, 9751 .stop = perf_swevent_stop, 9752 .read = perf_swevent_read, 9753 }; 9754 9755 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS) 9756 /* 9757 * Flags in config, used by dynamic PMU kprobe and uprobe 9758 * The flags should match following PMU_FORMAT_ATTR(). 9759 * 9760 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe 9761 * if not set, create kprobe/uprobe 9762 * 9763 * The following values specify a reference counter (or semaphore in the 9764 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically 9765 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset. 9766 * 9767 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset 9768 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left 9769 */ 9770 enum perf_probe_config { 9771 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */ 9772 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32, 9773 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS, 9774 }; 9775 9776 PMU_FORMAT_ATTR(retprobe, "config:0"); 9777 #endif 9778 9779 #ifdef CONFIG_KPROBE_EVENTS 9780 static struct attribute *kprobe_attrs[] = { 9781 &format_attr_retprobe.attr, 9782 NULL, 9783 }; 9784 9785 static struct attribute_group kprobe_format_group = { 9786 .name = "format", 9787 .attrs = kprobe_attrs, 9788 }; 9789 9790 static const struct attribute_group *kprobe_attr_groups[] = { 9791 &kprobe_format_group, 9792 NULL, 9793 }; 9794 9795 static int perf_kprobe_event_init(struct perf_event *event); 9796 static struct pmu perf_kprobe = { 9797 .task_ctx_nr = perf_sw_context, 9798 .event_init = perf_kprobe_event_init, 9799 .add = perf_trace_add, 9800 .del = perf_trace_del, 9801 .start = perf_swevent_start, 9802 .stop = perf_swevent_stop, 9803 .read = perf_swevent_read, 9804 .attr_groups = kprobe_attr_groups, 9805 }; 9806 9807 static int perf_kprobe_event_init(struct perf_event *event) 9808 { 9809 int err; 9810 bool is_retprobe; 9811 9812 if (event->attr.type != perf_kprobe.type) 9813 return -ENOENT; 9814 9815 if (!perfmon_capable()) 9816 return -EACCES; 9817 9818 /* 9819 * no branch sampling for probe events 9820 */ 9821 if (has_branch_stack(event)) 9822 return -EOPNOTSUPP; 9823 9824 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE; 9825 err = perf_kprobe_init(event, is_retprobe); 9826 if (err) 9827 return err; 9828 9829 event->destroy = perf_kprobe_destroy; 9830 9831 return 0; 9832 } 9833 #endif /* CONFIG_KPROBE_EVENTS */ 9834 9835 #ifdef CONFIG_UPROBE_EVENTS 9836 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63"); 9837 9838 static struct attribute *uprobe_attrs[] = { 9839 &format_attr_retprobe.attr, 9840 &format_attr_ref_ctr_offset.attr, 9841 NULL, 9842 }; 9843 9844 static struct attribute_group uprobe_format_group = { 9845 .name = "format", 9846 .attrs = uprobe_attrs, 9847 }; 9848 9849 static const struct attribute_group *uprobe_attr_groups[] = { 9850 &uprobe_format_group, 9851 NULL, 9852 }; 9853 9854 static int perf_uprobe_event_init(struct perf_event *event); 9855 static struct pmu perf_uprobe = { 9856 .task_ctx_nr = perf_sw_context, 9857 .event_init = perf_uprobe_event_init, 9858 .add = perf_trace_add, 9859 .del = perf_trace_del, 9860 .start = perf_swevent_start, 9861 .stop = perf_swevent_stop, 9862 .read = perf_swevent_read, 9863 .attr_groups = uprobe_attr_groups, 9864 }; 9865 9866 static int perf_uprobe_event_init(struct perf_event *event) 9867 { 9868 int err; 9869 unsigned long ref_ctr_offset; 9870 bool is_retprobe; 9871 9872 if (event->attr.type != perf_uprobe.type) 9873 return -ENOENT; 9874 9875 if (!perfmon_capable()) 9876 return -EACCES; 9877 9878 /* 9879 * no branch sampling for probe events 9880 */ 9881 if (has_branch_stack(event)) 9882 return -EOPNOTSUPP; 9883 9884 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE; 9885 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT; 9886 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe); 9887 if (err) 9888 return err; 9889 9890 event->destroy = perf_uprobe_destroy; 9891 9892 return 0; 9893 } 9894 #endif /* CONFIG_UPROBE_EVENTS */ 9895 9896 static inline void perf_tp_register(void) 9897 { 9898 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT); 9899 #ifdef CONFIG_KPROBE_EVENTS 9900 perf_pmu_register(&perf_kprobe, "kprobe", -1); 9901 #endif 9902 #ifdef CONFIG_UPROBE_EVENTS 9903 perf_pmu_register(&perf_uprobe, "uprobe", -1); 9904 #endif 9905 } 9906 9907 static void perf_event_free_filter(struct perf_event *event) 9908 { 9909 ftrace_profile_free_filter(event); 9910 } 9911 9912 #ifdef CONFIG_BPF_SYSCALL 9913 static void bpf_overflow_handler(struct perf_event *event, 9914 struct perf_sample_data *data, 9915 struct pt_regs *regs) 9916 { 9917 struct bpf_perf_event_data_kern ctx = { 9918 .data = data, 9919 .event = event, 9920 }; 9921 struct bpf_prog *prog; 9922 int ret = 0; 9923 9924 ctx.regs = perf_arch_bpf_user_pt_regs(regs); 9925 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) 9926 goto out; 9927 rcu_read_lock(); 9928 prog = READ_ONCE(event->prog); 9929 if (prog) 9930 ret = bpf_prog_run(prog, &ctx); 9931 rcu_read_unlock(); 9932 out: 9933 __this_cpu_dec(bpf_prog_active); 9934 if (!ret) 9935 return; 9936 9937 event->orig_overflow_handler(event, data, regs); 9938 } 9939 9940 static int perf_event_set_bpf_handler(struct perf_event *event, 9941 struct bpf_prog *prog, 9942 u64 bpf_cookie) 9943 { 9944 if (event->overflow_handler_context) 9945 /* hw breakpoint or kernel counter */ 9946 return -EINVAL; 9947 9948 if (event->prog) 9949 return -EEXIST; 9950 9951 if (prog->type != BPF_PROG_TYPE_PERF_EVENT) 9952 return -EINVAL; 9953 9954 if (event->attr.precise_ip && 9955 prog->call_get_stack && 9956 (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY) || 9957 event->attr.exclude_callchain_kernel || 9958 event->attr.exclude_callchain_user)) { 9959 /* 9960 * On perf_event with precise_ip, calling bpf_get_stack() 9961 * may trigger unwinder warnings and occasional crashes. 9962 * bpf_get_[stack|stackid] works around this issue by using 9963 * callchain attached to perf_sample_data. If the 9964 * perf_event does not full (kernel and user) callchain 9965 * attached to perf_sample_data, do not allow attaching BPF 9966 * program that calls bpf_get_[stack|stackid]. 9967 */ 9968 return -EPROTO; 9969 } 9970 9971 event->prog = prog; 9972 event->bpf_cookie = bpf_cookie; 9973 event->orig_overflow_handler = READ_ONCE(event->overflow_handler); 9974 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler); 9975 return 0; 9976 } 9977 9978 static void perf_event_free_bpf_handler(struct perf_event *event) 9979 { 9980 struct bpf_prog *prog = event->prog; 9981 9982 if (!prog) 9983 return; 9984 9985 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler); 9986 event->prog = NULL; 9987 bpf_prog_put(prog); 9988 } 9989 #else 9990 static int perf_event_set_bpf_handler(struct perf_event *event, 9991 struct bpf_prog *prog, 9992 u64 bpf_cookie) 9993 { 9994 return -EOPNOTSUPP; 9995 } 9996 static void perf_event_free_bpf_handler(struct perf_event *event) 9997 { 9998 } 9999 #endif 10000 10001 /* 10002 * returns true if the event is a tracepoint, or a kprobe/upprobe created 10003 * with perf_event_open() 10004 */ 10005 static inline bool perf_event_is_tracing(struct perf_event *event) 10006 { 10007 if (event->pmu == &perf_tracepoint) 10008 return true; 10009 #ifdef CONFIG_KPROBE_EVENTS 10010 if (event->pmu == &perf_kprobe) 10011 return true; 10012 #endif 10013 #ifdef CONFIG_UPROBE_EVENTS 10014 if (event->pmu == &perf_uprobe) 10015 return true; 10016 #endif 10017 return false; 10018 } 10019 10020 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog, 10021 u64 bpf_cookie) 10022 { 10023 bool is_kprobe, is_tracepoint, is_syscall_tp; 10024 10025 if (!perf_event_is_tracing(event)) 10026 return perf_event_set_bpf_handler(event, prog, bpf_cookie); 10027 10028 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE; 10029 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT; 10030 is_syscall_tp = is_syscall_trace_event(event->tp_event); 10031 if (!is_kprobe && !is_tracepoint && !is_syscall_tp) 10032 /* bpf programs can only be attached to u/kprobe or tracepoint */ 10033 return -EINVAL; 10034 10035 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) || 10036 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) || 10037 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) 10038 return -EINVAL; 10039 10040 /* Kprobe override only works for kprobes, not uprobes. */ 10041 if (prog->kprobe_override && 10042 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) 10043 return -EINVAL; 10044 10045 if (is_tracepoint || is_syscall_tp) { 10046 int off = trace_event_get_offsets(event->tp_event); 10047 10048 if (prog->aux->max_ctx_offset > off) 10049 return -EACCES; 10050 } 10051 10052 return perf_event_attach_bpf_prog(event, prog, bpf_cookie); 10053 } 10054 10055 void perf_event_free_bpf_prog(struct perf_event *event) 10056 { 10057 if (!perf_event_is_tracing(event)) { 10058 perf_event_free_bpf_handler(event); 10059 return; 10060 } 10061 perf_event_detach_bpf_prog(event); 10062 } 10063 10064 #else 10065 10066 static inline void perf_tp_register(void) 10067 { 10068 } 10069 10070 static void perf_event_free_filter(struct perf_event *event) 10071 { 10072 } 10073 10074 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog, 10075 u64 bpf_cookie) 10076 { 10077 return -ENOENT; 10078 } 10079 10080 void perf_event_free_bpf_prog(struct perf_event *event) 10081 { 10082 } 10083 #endif /* CONFIG_EVENT_TRACING */ 10084 10085 #ifdef CONFIG_HAVE_HW_BREAKPOINT 10086 void perf_bp_event(struct perf_event *bp, void *data) 10087 { 10088 struct perf_sample_data sample; 10089 struct pt_regs *regs = data; 10090 10091 perf_sample_data_init(&sample, bp->attr.bp_addr, 0); 10092 10093 if (!bp->hw.state && !perf_exclude_event(bp, regs)) 10094 perf_swevent_event(bp, 1, &sample, regs); 10095 } 10096 #endif 10097 10098 /* 10099 * Allocate a new address filter 10100 */ 10101 static struct perf_addr_filter * 10102 perf_addr_filter_new(struct perf_event *event, struct list_head *filters) 10103 { 10104 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu); 10105 struct perf_addr_filter *filter; 10106 10107 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node); 10108 if (!filter) 10109 return NULL; 10110 10111 INIT_LIST_HEAD(&filter->entry); 10112 list_add_tail(&filter->entry, filters); 10113 10114 return filter; 10115 } 10116 10117 static void free_filters_list(struct list_head *filters) 10118 { 10119 struct perf_addr_filter *filter, *iter; 10120 10121 list_for_each_entry_safe(filter, iter, filters, entry) { 10122 path_put(&filter->path); 10123 list_del(&filter->entry); 10124 kfree(filter); 10125 } 10126 } 10127 10128 /* 10129 * Free existing address filters and optionally install new ones 10130 */ 10131 static void perf_addr_filters_splice(struct perf_event *event, 10132 struct list_head *head) 10133 { 10134 unsigned long flags; 10135 LIST_HEAD(list); 10136 10137 if (!has_addr_filter(event)) 10138 return; 10139 10140 /* don't bother with children, they don't have their own filters */ 10141 if (event->parent) 10142 return; 10143 10144 raw_spin_lock_irqsave(&event->addr_filters.lock, flags); 10145 10146 list_splice_init(&event->addr_filters.list, &list); 10147 if (head) 10148 list_splice(head, &event->addr_filters.list); 10149 10150 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags); 10151 10152 free_filters_list(&list); 10153 } 10154 10155 /* 10156 * Scan through mm's vmas and see if one of them matches the 10157 * @filter; if so, adjust filter's address range. 10158 * Called with mm::mmap_lock down for reading. 10159 */ 10160 static void perf_addr_filter_apply(struct perf_addr_filter *filter, 10161 struct mm_struct *mm, 10162 struct perf_addr_filter_range *fr) 10163 { 10164 struct vm_area_struct *vma; 10165 10166 for (vma = mm->mmap; vma; vma = vma->vm_next) { 10167 if (!vma->vm_file) 10168 continue; 10169 10170 if (perf_addr_filter_vma_adjust(filter, vma, fr)) 10171 return; 10172 } 10173 } 10174 10175 /* 10176 * Update event's address range filters based on the 10177 * task's existing mappings, if any. 10178 */ 10179 static void perf_event_addr_filters_apply(struct perf_event *event) 10180 { 10181 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 10182 struct task_struct *task = READ_ONCE(event->ctx->task); 10183 struct perf_addr_filter *filter; 10184 struct mm_struct *mm = NULL; 10185 unsigned int count = 0; 10186 unsigned long flags; 10187 10188 /* 10189 * We may observe TASK_TOMBSTONE, which means that the event tear-down 10190 * will stop on the parent's child_mutex that our caller is also holding 10191 */ 10192 if (task == TASK_TOMBSTONE) 10193 return; 10194 10195 if (ifh->nr_file_filters) { 10196 mm = get_task_mm(task); 10197 if (!mm) 10198 goto restart; 10199 10200 mmap_read_lock(mm); 10201 } 10202 10203 raw_spin_lock_irqsave(&ifh->lock, flags); 10204 list_for_each_entry(filter, &ifh->list, entry) { 10205 if (filter->path.dentry) { 10206 /* 10207 * Adjust base offset if the filter is associated to a 10208 * binary that needs to be mapped: 10209 */ 10210 event->addr_filter_ranges[count].start = 0; 10211 event->addr_filter_ranges[count].size = 0; 10212 10213 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]); 10214 } else { 10215 event->addr_filter_ranges[count].start = filter->offset; 10216 event->addr_filter_ranges[count].size = filter->size; 10217 } 10218 10219 count++; 10220 } 10221 10222 event->addr_filters_gen++; 10223 raw_spin_unlock_irqrestore(&ifh->lock, flags); 10224 10225 if (ifh->nr_file_filters) { 10226 mmap_read_unlock(mm); 10227 10228 mmput(mm); 10229 } 10230 10231 restart: 10232 perf_event_stop(event, 1); 10233 } 10234 10235 /* 10236 * Address range filtering: limiting the data to certain 10237 * instruction address ranges. Filters are ioctl()ed to us from 10238 * userspace as ascii strings. 10239 * 10240 * Filter string format: 10241 * 10242 * ACTION RANGE_SPEC 10243 * where ACTION is one of the 10244 * * "filter": limit the trace to this region 10245 * * "start": start tracing from this address 10246 * * "stop": stop tracing at this address/region; 10247 * RANGE_SPEC is 10248 * * for kernel addresses: <start address>[/<size>] 10249 * * for object files: <start address>[/<size>]@</path/to/object/file> 10250 * 10251 * if <size> is not specified or is zero, the range is treated as a single 10252 * address; not valid for ACTION=="filter". 10253 */ 10254 enum { 10255 IF_ACT_NONE = -1, 10256 IF_ACT_FILTER, 10257 IF_ACT_START, 10258 IF_ACT_STOP, 10259 IF_SRC_FILE, 10260 IF_SRC_KERNEL, 10261 IF_SRC_FILEADDR, 10262 IF_SRC_KERNELADDR, 10263 }; 10264 10265 enum { 10266 IF_STATE_ACTION = 0, 10267 IF_STATE_SOURCE, 10268 IF_STATE_END, 10269 }; 10270 10271 static const match_table_t if_tokens = { 10272 { IF_ACT_FILTER, "filter" }, 10273 { IF_ACT_START, "start" }, 10274 { IF_ACT_STOP, "stop" }, 10275 { IF_SRC_FILE, "%u/%u@%s" }, 10276 { IF_SRC_KERNEL, "%u/%u" }, 10277 { IF_SRC_FILEADDR, "%u@%s" }, 10278 { IF_SRC_KERNELADDR, "%u" }, 10279 { IF_ACT_NONE, NULL }, 10280 }; 10281 10282 /* 10283 * Address filter string parser 10284 */ 10285 static int 10286 perf_event_parse_addr_filter(struct perf_event *event, char *fstr, 10287 struct list_head *filters) 10288 { 10289 struct perf_addr_filter *filter = NULL; 10290 char *start, *orig, *filename = NULL; 10291 substring_t args[MAX_OPT_ARGS]; 10292 int state = IF_STATE_ACTION, token; 10293 unsigned int kernel = 0; 10294 int ret = -EINVAL; 10295 10296 orig = fstr = kstrdup(fstr, GFP_KERNEL); 10297 if (!fstr) 10298 return -ENOMEM; 10299 10300 while ((start = strsep(&fstr, " ,\n")) != NULL) { 10301 static const enum perf_addr_filter_action_t actions[] = { 10302 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER, 10303 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START, 10304 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP, 10305 }; 10306 ret = -EINVAL; 10307 10308 if (!*start) 10309 continue; 10310 10311 /* filter definition begins */ 10312 if (state == IF_STATE_ACTION) { 10313 filter = perf_addr_filter_new(event, filters); 10314 if (!filter) 10315 goto fail; 10316 } 10317 10318 token = match_token(start, if_tokens, args); 10319 switch (token) { 10320 case IF_ACT_FILTER: 10321 case IF_ACT_START: 10322 case IF_ACT_STOP: 10323 if (state != IF_STATE_ACTION) 10324 goto fail; 10325 10326 filter->action = actions[token]; 10327 state = IF_STATE_SOURCE; 10328 break; 10329 10330 case IF_SRC_KERNELADDR: 10331 case IF_SRC_KERNEL: 10332 kernel = 1; 10333 fallthrough; 10334 10335 case IF_SRC_FILEADDR: 10336 case IF_SRC_FILE: 10337 if (state != IF_STATE_SOURCE) 10338 goto fail; 10339 10340 *args[0].to = 0; 10341 ret = kstrtoul(args[0].from, 0, &filter->offset); 10342 if (ret) 10343 goto fail; 10344 10345 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) { 10346 *args[1].to = 0; 10347 ret = kstrtoul(args[1].from, 0, &filter->size); 10348 if (ret) 10349 goto fail; 10350 } 10351 10352 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) { 10353 int fpos = token == IF_SRC_FILE ? 2 : 1; 10354 10355 kfree(filename); 10356 filename = match_strdup(&args[fpos]); 10357 if (!filename) { 10358 ret = -ENOMEM; 10359 goto fail; 10360 } 10361 } 10362 10363 state = IF_STATE_END; 10364 break; 10365 10366 default: 10367 goto fail; 10368 } 10369 10370 /* 10371 * Filter definition is fully parsed, validate and install it. 10372 * Make sure that it doesn't contradict itself or the event's 10373 * attribute. 10374 */ 10375 if (state == IF_STATE_END) { 10376 ret = -EINVAL; 10377 if (kernel && event->attr.exclude_kernel) 10378 goto fail; 10379 10380 /* 10381 * ACTION "filter" must have a non-zero length region 10382 * specified. 10383 */ 10384 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER && 10385 !filter->size) 10386 goto fail; 10387 10388 if (!kernel) { 10389 if (!filename) 10390 goto fail; 10391 10392 /* 10393 * For now, we only support file-based filters 10394 * in per-task events; doing so for CPU-wide 10395 * events requires additional context switching 10396 * trickery, since same object code will be 10397 * mapped at different virtual addresses in 10398 * different processes. 10399 */ 10400 ret = -EOPNOTSUPP; 10401 if (!event->ctx->task) 10402 goto fail; 10403 10404 /* look up the path and grab its inode */ 10405 ret = kern_path(filename, LOOKUP_FOLLOW, 10406 &filter->path); 10407 if (ret) 10408 goto fail; 10409 10410 ret = -EINVAL; 10411 if (!filter->path.dentry || 10412 !S_ISREG(d_inode(filter->path.dentry) 10413 ->i_mode)) 10414 goto fail; 10415 10416 event->addr_filters.nr_file_filters++; 10417 } 10418 10419 /* ready to consume more filters */ 10420 state = IF_STATE_ACTION; 10421 filter = NULL; 10422 } 10423 } 10424 10425 if (state != IF_STATE_ACTION) 10426 goto fail; 10427 10428 kfree(filename); 10429 kfree(orig); 10430 10431 return 0; 10432 10433 fail: 10434 kfree(filename); 10435 free_filters_list(filters); 10436 kfree(orig); 10437 10438 return ret; 10439 } 10440 10441 static int 10442 perf_event_set_addr_filter(struct perf_event *event, char *filter_str) 10443 { 10444 LIST_HEAD(filters); 10445 int ret; 10446 10447 /* 10448 * Since this is called in perf_ioctl() path, we're already holding 10449 * ctx::mutex. 10450 */ 10451 lockdep_assert_held(&event->ctx->mutex); 10452 10453 if (WARN_ON_ONCE(event->parent)) 10454 return -EINVAL; 10455 10456 ret = perf_event_parse_addr_filter(event, filter_str, &filters); 10457 if (ret) 10458 goto fail_clear_files; 10459 10460 ret = event->pmu->addr_filters_validate(&filters); 10461 if (ret) 10462 goto fail_free_filters; 10463 10464 /* remove existing filters, if any */ 10465 perf_addr_filters_splice(event, &filters); 10466 10467 /* install new filters */ 10468 perf_event_for_each_child(event, perf_event_addr_filters_apply); 10469 10470 return ret; 10471 10472 fail_free_filters: 10473 free_filters_list(&filters); 10474 10475 fail_clear_files: 10476 event->addr_filters.nr_file_filters = 0; 10477 10478 return ret; 10479 } 10480 10481 static int perf_event_set_filter(struct perf_event *event, void __user *arg) 10482 { 10483 int ret = -EINVAL; 10484 char *filter_str; 10485 10486 filter_str = strndup_user(arg, PAGE_SIZE); 10487 if (IS_ERR(filter_str)) 10488 return PTR_ERR(filter_str); 10489 10490 #ifdef CONFIG_EVENT_TRACING 10491 if (perf_event_is_tracing(event)) { 10492 struct perf_event_context *ctx = event->ctx; 10493 10494 /* 10495 * Beware, here be dragons!! 10496 * 10497 * the tracepoint muck will deadlock against ctx->mutex, but 10498 * the tracepoint stuff does not actually need it. So 10499 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we 10500 * already have a reference on ctx. 10501 * 10502 * This can result in event getting moved to a different ctx, 10503 * but that does not affect the tracepoint state. 10504 */ 10505 mutex_unlock(&ctx->mutex); 10506 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str); 10507 mutex_lock(&ctx->mutex); 10508 } else 10509 #endif 10510 if (has_addr_filter(event)) 10511 ret = perf_event_set_addr_filter(event, filter_str); 10512 10513 kfree(filter_str); 10514 return ret; 10515 } 10516 10517 /* 10518 * hrtimer based swevent callback 10519 */ 10520 10521 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer) 10522 { 10523 enum hrtimer_restart ret = HRTIMER_RESTART; 10524 struct perf_sample_data data; 10525 struct pt_regs *regs; 10526 struct perf_event *event; 10527 u64 period; 10528 10529 event = container_of(hrtimer, struct perf_event, hw.hrtimer); 10530 10531 if (event->state != PERF_EVENT_STATE_ACTIVE) 10532 return HRTIMER_NORESTART; 10533 10534 event->pmu->read(event); 10535 10536 perf_sample_data_init(&data, 0, event->hw.last_period); 10537 regs = get_irq_regs(); 10538 10539 if (regs && !perf_exclude_event(event, regs)) { 10540 if (!(event->attr.exclude_idle && is_idle_task(current))) 10541 if (__perf_event_overflow(event, 1, &data, regs)) 10542 ret = HRTIMER_NORESTART; 10543 } 10544 10545 period = max_t(u64, 10000, event->hw.sample_period); 10546 hrtimer_forward_now(hrtimer, ns_to_ktime(period)); 10547 10548 return ret; 10549 } 10550 10551 static void perf_swevent_start_hrtimer(struct perf_event *event) 10552 { 10553 struct hw_perf_event *hwc = &event->hw; 10554 s64 period; 10555 10556 if (!is_sampling_event(event)) 10557 return; 10558 10559 period = local64_read(&hwc->period_left); 10560 if (period) { 10561 if (period < 0) 10562 period = 10000; 10563 10564 local64_set(&hwc->period_left, 0); 10565 } else { 10566 period = max_t(u64, 10000, hwc->sample_period); 10567 } 10568 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period), 10569 HRTIMER_MODE_REL_PINNED_HARD); 10570 } 10571 10572 static void perf_swevent_cancel_hrtimer(struct perf_event *event) 10573 { 10574 struct hw_perf_event *hwc = &event->hw; 10575 10576 if (is_sampling_event(event)) { 10577 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer); 10578 local64_set(&hwc->period_left, ktime_to_ns(remaining)); 10579 10580 hrtimer_cancel(&hwc->hrtimer); 10581 } 10582 } 10583 10584 static void perf_swevent_init_hrtimer(struct perf_event *event) 10585 { 10586 struct hw_perf_event *hwc = &event->hw; 10587 10588 if (!is_sampling_event(event)) 10589 return; 10590 10591 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); 10592 hwc->hrtimer.function = perf_swevent_hrtimer; 10593 10594 /* 10595 * Since hrtimers have a fixed rate, we can do a static freq->period 10596 * mapping and avoid the whole period adjust feedback stuff. 10597 */ 10598 if (event->attr.freq) { 10599 long freq = event->attr.sample_freq; 10600 10601 event->attr.sample_period = NSEC_PER_SEC / freq; 10602 hwc->sample_period = event->attr.sample_period; 10603 local64_set(&hwc->period_left, hwc->sample_period); 10604 hwc->last_period = hwc->sample_period; 10605 event->attr.freq = 0; 10606 } 10607 } 10608 10609 /* 10610 * Software event: cpu wall time clock 10611 */ 10612 10613 static void cpu_clock_event_update(struct perf_event *event) 10614 { 10615 s64 prev; 10616 u64 now; 10617 10618 now = local_clock(); 10619 prev = local64_xchg(&event->hw.prev_count, now); 10620 local64_add(now - prev, &event->count); 10621 } 10622 10623 static void cpu_clock_event_start(struct perf_event *event, int flags) 10624 { 10625 local64_set(&event->hw.prev_count, local_clock()); 10626 perf_swevent_start_hrtimer(event); 10627 } 10628 10629 static void cpu_clock_event_stop(struct perf_event *event, int flags) 10630 { 10631 perf_swevent_cancel_hrtimer(event); 10632 cpu_clock_event_update(event); 10633 } 10634 10635 static int cpu_clock_event_add(struct perf_event *event, int flags) 10636 { 10637 if (flags & PERF_EF_START) 10638 cpu_clock_event_start(event, flags); 10639 perf_event_update_userpage(event); 10640 10641 return 0; 10642 } 10643 10644 static void cpu_clock_event_del(struct perf_event *event, int flags) 10645 { 10646 cpu_clock_event_stop(event, flags); 10647 } 10648 10649 static void cpu_clock_event_read(struct perf_event *event) 10650 { 10651 cpu_clock_event_update(event); 10652 } 10653 10654 static int cpu_clock_event_init(struct perf_event *event) 10655 { 10656 if (event->attr.type != PERF_TYPE_SOFTWARE) 10657 return -ENOENT; 10658 10659 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK) 10660 return -ENOENT; 10661 10662 /* 10663 * no branch sampling for software events 10664 */ 10665 if (has_branch_stack(event)) 10666 return -EOPNOTSUPP; 10667 10668 perf_swevent_init_hrtimer(event); 10669 10670 return 0; 10671 } 10672 10673 static struct pmu perf_cpu_clock = { 10674 .task_ctx_nr = perf_sw_context, 10675 10676 .capabilities = PERF_PMU_CAP_NO_NMI, 10677 10678 .event_init = cpu_clock_event_init, 10679 .add = cpu_clock_event_add, 10680 .del = cpu_clock_event_del, 10681 .start = cpu_clock_event_start, 10682 .stop = cpu_clock_event_stop, 10683 .read = cpu_clock_event_read, 10684 }; 10685 10686 /* 10687 * Software event: task time clock 10688 */ 10689 10690 static void task_clock_event_update(struct perf_event *event, u64 now) 10691 { 10692 u64 prev; 10693 s64 delta; 10694 10695 prev = local64_xchg(&event->hw.prev_count, now); 10696 delta = now - prev; 10697 local64_add(delta, &event->count); 10698 } 10699 10700 static void task_clock_event_start(struct perf_event *event, int flags) 10701 { 10702 local64_set(&event->hw.prev_count, event->ctx->time); 10703 perf_swevent_start_hrtimer(event); 10704 } 10705 10706 static void task_clock_event_stop(struct perf_event *event, int flags) 10707 { 10708 perf_swevent_cancel_hrtimer(event); 10709 task_clock_event_update(event, event->ctx->time); 10710 } 10711 10712 static int task_clock_event_add(struct perf_event *event, int flags) 10713 { 10714 if (flags & PERF_EF_START) 10715 task_clock_event_start(event, flags); 10716 perf_event_update_userpage(event); 10717 10718 return 0; 10719 } 10720 10721 static void task_clock_event_del(struct perf_event *event, int flags) 10722 { 10723 task_clock_event_stop(event, PERF_EF_UPDATE); 10724 } 10725 10726 static void task_clock_event_read(struct perf_event *event) 10727 { 10728 u64 now = perf_clock(); 10729 u64 delta = now - event->ctx->timestamp; 10730 u64 time = event->ctx->time + delta; 10731 10732 task_clock_event_update(event, time); 10733 } 10734 10735 static int task_clock_event_init(struct perf_event *event) 10736 { 10737 if (event->attr.type != PERF_TYPE_SOFTWARE) 10738 return -ENOENT; 10739 10740 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK) 10741 return -ENOENT; 10742 10743 /* 10744 * no branch sampling for software events 10745 */ 10746 if (has_branch_stack(event)) 10747 return -EOPNOTSUPP; 10748 10749 perf_swevent_init_hrtimer(event); 10750 10751 return 0; 10752 } 10753 10754 static struct pmu perf_task_clock = { 10755 .task_ctx_nr = perf_sw_context, 10756 10757 .capabilities = PERF_PMU_CAP_NO_NMI, 10758 10759 .event_init = task_clock_event_init, 10760 .add = task_clock_event_add, 10761 .del = task_clock_event_del, 10762 .start = task_clock_event_start, 10763 .stop = task_clock_event_stop, 10764 .read = task_clock_event_read, 10765 }; 10766 10767 static void perf_pmu_nop_void(struct pmu *pmu) 10768 { 10769 } 10770 10771 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags) 10772 { 10773 } 10774 10775 static int perf_pmu_nop_int(struct pmu *pmu) 10776 { 10777 return 0; 10778 } 10779 10780 static int perf_event_nop_int(struct perf_event *event, u64 value) 10781 { 10782 return 0; 10783 } 10784 10785 static DEFINE_PER_CPU(unsigned int, nop_txn_flags); 10786 10787 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags) 10788 { 10789 __this_cpu_write(nop_txn_flags, flags); 10790 10791 if (flags & ~PERF_PMU_TXN_ADD) 10792 return; 10793 10794 perf_pmu_disable(pmu); 10795 } 10796 10797 static int perf_pmu_commit_txn(struct pmu *pmu) 10798 { 10799 unsigned int flags = __this_cpu_read(nop_txn_flags); 10800 10801 __this_cpu_write(nop_txn_flags, 0); 10802 10803 if (flags & ~PERF_PMU_TXN_ADD) 10804 return 0; 10805 10806 perf_pmu_enable(pmu); 10807 return 0; 10808 } 10809 10810 static void perf_pmu_cancel_txn(struct pmu *pmu) 10811 { 10812 unsigned int flags = __this_cpu_read(nop_txn_flags); 10813 10814 __this_cpu_write(nop_txn_flags, 0); 10815 10816 if (flags & ~PERF_PMU_TXN_ADD) 10817 return; 10818 10819 perf_pmu_enable(pmu); 10820 } 10821 10822 static int perf_event_idx_default(struct perf_event *event) 10823 { 10824 return 0; 10825 } 10826 10827 /* 10828 * Ensures all contexts with the same task_ctx_nr have the same 10829 * pmu_cpu_context too. 10830 */ 10831 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn) 10832 { 10833 struct pmu *pmu; 10834 10835 if (ctxn < 0) 10836 return NULL; 10837 10838 list_for_each_entry(pmu, &pmus, entry) { 10839 if (pmu->task_ctx_nr == ctxn) 10840 return pmu->pmu_cpu_context; 10841 } 10842 10843 return NULL; 10844 } 10845 10846 static void free_pmu_context(struct pmu *pmu) 10847 { 10848 /* 10849 * Static contexts such as perf_sw_context have a global lifetime 10850 * and may be shared between different PMUs. Avoid freeing them 10851 * when a single PMU is going away. 10852 */ 10853 if (pmu->task_ctx_nr > perf_invalid_context) 10854 return; 10855 10856 free_percpu(pmu->pmu_cpu_context); 10857 } 10858 10859 /* 10860 * Let userspace know that this PMU supports address range filtering: 10861 */ 10862 static ssize_t nr_addr_filters_show(struct device *dev, 10863 struct device_attribute *attr, 10864 char *page) 10865 { 10866 struct pmu *pmu = dev_get_drvdata(dev); 10867 10868 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters); 10869 } 10870 DEVICE_ATTR_RO(nr_addr_filters); 10871 10872 static struct idr pmu_idr; 10873 10874 static ssize_t 10875 type_show(struct device *dev, struct device_attribute *attr, char *page) 10876 { 10877 struct pmu *pmu = dev_get_drvdata(dev); 10878 10879 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type); 10880 } 10881 static DEVICE_ATTR_RO(type); 10882 10883 static ssize_t 10884 perf_event_mux_interval_ms_show(struct device *dev, 10885 struct device_attribute *attr, 10886 char *page) 10887 { 10888 struct pmu *pmu = dev_get_drvdata(dev); 10889 10890 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms); 10891 } 10892 10893 static DEFINE_MUTEX(mux_interval_mutex); 10894 10895 static ssize_t 10896 perf_event_mux_interval_ms_store(struct device *dev, 10897 struct device_attribute *attr, 10898 const char *buf, size_t count) 10899 { 10900 struct pmu *pmu = dev_get_drvdata(dev); 10901 int timer, cpu, ret; 10902 10903 ret = kstrtoint(buf, 0, &timer); 10904 if (ret) 10905 return ret; 10906 10907 if (timer < 1) 10908 return -EINVAL; 10909 10910 /* same value, noting to do */ 10911 if (timer == pmu->hrtimer_interval_ms) 10912 return count; 10913 10914 mutex_lock(&mux_interval_mutex); 10915 pmu->hrtimer_interval_ms = timer; 10916 10917 /* update all cpuctx for this PMU */ 10918 cpus_read_lock(); 10919 for_each_online_cpu(cpu) { 10920 struct perf_cpu_context *cpuctx; 10921 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 10922 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer); 10923 10924 cpu_function_call(cpu, 10925 (remote_function_f)perf_mux_hrtimer_restart, cpuctx); 10926 } 10927 cpus_read_unlock(); 10928 mutex_unlock(&mux_interval_mutex); 10929 10930 return count; 10931 } 10932 static DEVICE_ATTR_RW(perf_event_mux_interval_ms); 10933 10934 static struct attribute *pmu_dev_attrs[] = { 10935 &dev_attr_type.attr, 10936 &dev_attr_perf_event_mux_interval_ms.attr, 10937 NULL, 10938 }; 10939 ATTRIBUTE_GROUPS(pmu_dev); 10940 10941 static int pmu_bus_running; 10942 static struct bus_type pmu_bus = { 10943 .name = "event_source", 10944 .dev_groups = pmu_dev_groups, 10945 }; 10946 10947 static void pmu_dev_release(struct device *dev) 10948 { 10949 kfree(dev); 10950 } 10951 10952 static int pmu_dev_alloc(struct pmu *pmu) 10953 { 10954 int ret = -ENOMEM; 10955 10956 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL); 10957 if (!pmu->dev) 10958 goto out; 10959 10960 pmu->dev->groups = pmu->attr_groups; 10961 device_initialize(pmu->dev); 10962 ret = dev_set_name(pmu->dev, "%s", pmu->name); 10963 if (ret) 10964 goto free_dev; 10965 10966 dev_set_drvdata(pmu->dev, pmu); 10967 pmu->dev->bus = &pmu_bus; 10968 pmu->dev->release = pmu_dev_release; 10969 ret = device_add(pmu->dev); 10970 if (ret) 10971 goto free_dev; 10972 10973 /* For PMUs with address filters, throw in an extra attribute: */ 10974 if (pmu->nr_addr_filters) 10975 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters); 10976 10977 if (ret) 10978 goto del_dev; 10979 10980 if (pmu->attr_update) 10981 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update); 10982 10983 if (ret) 10984 goto del_dev; 10985 10986 out: 10987 return ret; 10988 10989 del_dev: 10990 device_del(pmu->dev); 10991 10992 free_dev: 10993 put_device(pmu->dev); 10994 goto out; 10995 } 10996 10997 static struct lock_class_key cpuctx_mutex; 10998 static struct lock_class_key cpuctx_lock; 10999 11000 int perf_pmu_register(struct pmu *pmu, const char *name, int type) 11001 { 11002 int cpu, ret, max = PERF_TYPE_MAX; 11003 11004 mutex_lock(&pmus_lock); 11005 ret = -ENOMEM; 11006 pmu->pmu_disable_count = alloc_percpu(int); 11007 if (!pmu->pmu_disable_count) 11008 goto unlock; 11009 11010 pmu->type = -1; 11011 if (!name) 11012 goto skip_type; 11013 pmu->name = name; 11014 11015 if (type != PERF_TYPE_SOFTWARE) { 11016 if (type >= 0) 11017 max = type; 11018 11019 ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL); 11020 if (ret < 0) 11021 goto free_pdc; 11022 11023 WARN_ON(type >= 0 && ret != type); 11024 11025 type = ret; 11026 } 11027 pmu->type = type; 11028 11029 if (pmu_bus_running) { 11030 ret = pmu_dev_alloc(pmu); 11031 if (ret) 11032 goto free_idr; 11033 } 11034 11035 skip_type: 11036 if (pmu->task_ctx_nr == perf_hw_context) { 11037 static int hw_context_taken = 0; 11038 11039 /* 11040 * Other than systems with heterogeneous CPUs, it never makes 11041 * sense for two PMUs to share perf_hw_context. PMUs which are 11042 * uncore must use perf_invalid_context. 11043 */ 11044 if (WARN_ON_ONCE(hw_context_taken && 11045 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS))) 11046 pmu->task_ctx_nr = perf_invalid_context; 11047 11048 hw_context_taken = 1; 11049 } 11050 11051 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr); 11052 if (pmu->pmu_cpu_context) 11053 goto got_cpu_context; 11054 11055 ret = -ENOMEM; 11056 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context); 11057 if (!pmu->pmu_cpu_context) 11058 goto free_dev; 11059 11060 for_each_possible_cpu(cpu) { 11061 struct perf_cpu_context *cpuctx; 11062 11063 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 11064 __perf_event_init_context(&cpuctx->ctx); 11065 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex); 11066 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock); 11067 cpuctx->ctx.pmu = pmu; 11068 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask); 11069 11070 __perf_mux_hrtimer_init(cpuctx, cpu); 11071 11072 cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default); 11073 cpuctx->heap = cpuctx->heap_default; 11074 } 11075 11076 got_cpu_context: 11077 if (!pmu->start_txn) { 11078 if (pmu->pmu_enable) { 11079 /* 11080 * If we have pmu_enable/pmu_disable calls, install 11081 * transaction stubs that use that to try and batch 11082 * hardware accesses. 11083 */ 11084 pmu->start_txn = perf_pmu_start_txn; 11085 pmu->commit_txn = perf_pmu_commit_txn; 11086 pmu->cancel_txn = perf_pmu_cancel_txn; 11087 } else { 11088 pmu->start_txn = perf_pmu_nop_txn; 11089 pmu->commit_txn = perf_pmu_nop_int; 11090 pmu->cancel_txn = perf_pmu_nop_void; 11091 } 11092 } 11093 11094 if (!pmu->pmu_enable) { 11095 pmu->pmu_enable = perf_pmu_nop_void; 11096 pmu->pmu_disable = perf_pmu_nop_void; 11097 } 11098 11099 if (!pmu->check_period) 11100 pmu->check_period = perf_event_nop_int; 11101 11102 if (!pmu->event_idx) 11103 pmu->event_idx = perf_event_idx_default; 11104 11105 /* 11106 * Ensure the TYPE_SOFTWARE PMUs are at the head of the list, 11107 * since these cannot be in the IDR. This way the linear search 11108 * is fast, provided a valid software event is provided. 11109 */ 11110 if (type == PERF_TYPE_SOFTWARE || !name) 11111 list_add_rcu(&pmu->entry, &pmus); 11112 else 11113 list_add_tail_rcu(&pmu->entry, &pmus); 11114 11115 atomic_set(&pmu->exclusive_cnt, 0); 11116 ret = 0; 11117 unlock: 11118 mutex_unlock(&pmus_lock); 11119 11120 return ret; 11121 11122 free_dev: 11123 device_del(pmu->dev); 11124 put_device(pmu->dev); 11125 11126 free_idr: 11127 if (pmu->type != PERF_TYPE_SOFTWARE) 11128 idr_remove(&pmu_idr, pmu->type); 11129 11130 free_pdc: 11131 free_percpu(pmu->pmu_disable_count); 11132 goto unlock; 11133 } 11134 EXPORT_SYMBOL_GPL(perf_pmu_register); 11135 11136 void perf_pmu_unregister(struct pmu *pmu) 11137 { 11138 mutex_lock(&pmus_lock); 11139 list_del_rcu(&pmu->entry); 11140 11141 /* 11142 * We dereference the pmu list under both SRCU and regular RCU, so 11143 * synchronize against both of those. 11144 */ 11145 synchronize_srcu(&pmus_srcu); 11146 synchronize_rcu(); 11147 11148 free_percpu(pmu->pmu_disable_count); 11149 if (pmu->type != PERF_TYPE_SOFTWARE) 11150 idr_remove(&pmu_idr, pmu->type); 11151 if (pmu_bus_running) { 11152 if (pmu->nr_addr_filters) 11153 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters); 11154 device_del(pmu->dev); 11155 put_device(pmu->dev); 11156 } 11157 free_pmu_context(pmu); 11158 mutex_unlock(&pmus_lock); 11159 } 11160 EXPORT_SYMBOL_GPL(perf_pmu_unregister); 11161 11162 static inline bool has_extended_regs(struct perf_event *event) 11163 { 11164 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) || 11165 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK); 11166 } 11167 11168 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event) 11169 { 11170 struct perf_event_context *ctx = NULL; 11171 int ret; 11172 11173 if (!try_module_get(pmu->module)) 11174 return -ENODEV; 11175 11176 /* 11177 * A number of pmu->event_init() methods iterate the sibling_list to, 11178 * for example, validate if the group fits on the PMU. Therefore, 11179 * if this is a sibling event, acquire the ctx->mutex to protect 11180 * the sibling_list. 11181 */ 11182 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) { 11183 /* 11184 * This ctx->mutex can nest when we're called through 11185 * inheritance. See the perf_event_ctx_lock_nested() comment. 11186 */ 11187 ctx = perf_event_ctx_lock_nested(event->group_leader, 11188 SINGLE_DEPTH_NESTING); 11189 BUG_ON(!ctx); 11190 } 11191 11192 event->pmu = pmu; 11193 ret = pmu->event_init(event); 11194 11195 if (ctx) 11196 perf_event_ctx_unlock(event->group_leader, ctx); 11197 11198 if (!ret) { 11199 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) && 11200 has_extended_regs(event)) 11201 ret = -EOPNOTSUPP; 11202 11203 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE && 11204 event_has_any_exclude_flag(event)) 11205 ret = -EINVAL; 11206 11207 if (ret && event->destroy) 11208 event->destroy(event); 11209 } 11210 11211 if (ret) 11212 module_put(pmu->module); 11213 11214 return ret; 11215 } 11216 11217 static struct pmu *perf_init_event(struct perf_event *event) 11218 { 11219 bool extended_type = false; 11220 int idx, type, ret; 11221 struct pmu *pmu; 11222 11223 idx = srcu_read_lock(&pmus_srcu); 11224 11225 /* Try parent's PMU first: */ 11226 if (event->parent && event->parent->pmu) { 11227 pmu = event->parent->pmu; 11228 ret = perf_try_init_event(pmu, event); 11229 if (!ret) 11230 goto unlock; 11231 } 11232 11233 /* 11234 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE 11235 * are often aliases for PERF_TYPE_RAW. 11236 */ 11237 type = event->attr.type; 11238 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) { 11239 type = event->attr.config >> PERF_PMU_TYPE_SHIFT; 11240 if (!type) { 11241 type = PERF_TYPE_RAW; 11242 } else { 11243 extended_type = true; 11244 event->attr.config &= PERF_HW_EVENT_MASK; 11245 } 11246 } 11247 11248 again: 11249 rcu_read_lock(); 11250 pmu = idr_find(&pmu_idr, type); 11251 rcu_read_unlock(); 11252 if (pmu) { 11253 if (event->attr.type != type && type != PERF_TYPE_RAW && 11254 !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE)) 11255 goto fail; 11256 11257 ret = perf_try_init_event(pmu, event); 11258 if (ret == -ENOENT && event->attr.type != type && !extended_type) { 11259 type = event->attr.type; 11260 goto again; 11261 } 11262 11263 if (ret) 11264 pmu = ERR_PTR(ret); 11265 11266 goto unlock; 11267 } 11268 11269 list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) { 11270 ret = perf_try_init_event(pmu, event); 11271 if (!ret) 11272 goto unlock; 11273 11274 if (ret != -ENOENT) { 11275 pmu = ERR_PTR(ret); 11276 goto unlock; 11277 } 11278 } 11279 fail: 11280 pmu = ERR_PTR(-ENOENT); 11281 unlock: 11282 srcu_read_unlock(&pmus_srcu, idx); 11283 11284 return pmu; 11285 } 11286 11287 static void attach_sb_event(struct perf_event *event) 11288 { 11289 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu); 11290 11291 raw_spin_lock(&pel->lock); 11292 list_add_rcu(&event->sb_list, &pel->list); 11293 raw_spin_unlock(&pel->lock); 11294 } 11295 11296 /* 11297 * We keep a list of all !task (and therefore per-cpu) events 11298 * that need to receive side-band records. 11299 * 11300 * This avoids having to scan all the various PMU per-cpu contexts 11301 * looking for them. 11302 */ 11303 static void account_pmu_sb_event(struct perf_event *event) 11304 { 11305 if (is_sb_event(event)) 11306 attach_sb_event(event); 11307 } 11308 11309 static void account_event_cpu(struct perf_event *event, int cpu) 11310 { 11311 if (event->parent) 11312 return; 11313 11314 if (is_cgroup_event(event)) 11315 atomic_inc(&per_cpu(perf_cgroup_events, cpu)); 11316 } 11317 11318 /* Freq events need the tick to stay alive (see perf_event_task_tick). */ 11319 static void account_freq_event_nohz(void) 11320 { 11321 #ifdef CONFIG_NO_HZ_FULL 11322 /* Lock so we don't race with concurrent unaccount */ 11323 spin_lock(&nr_freq_lock); 11324 if (atomic_inc_return(&nr_freq_events) == 1) 11325 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS); 11326 spin_unlock(&nr_freq_lock); 11327 #endif 11328 } 11329 11330 static void account_freq_event(void) 11331 { 11332 if (tick_nohz_full_enabled()) 11333 account_freq_event_nohz(); 11334 else 11335 atomic_inc(&nr_freq_events); 11336 } 11337 11338 11339 static void account_event(struct perf_event *event) 11340 { 11341 bool inc = false; 11342 11343 if (event->parent) 11344 return; 11345 11346 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB)) 11347 inc = true; 11348 if (event->attr.mmap || event->attr.mmap_data) 11349 atomic_inc(&nr_mmap_events); 11350 if (event->attr.build_id) 11351 atomic_inc(&nr_build_id_events); 11352 if (event->attr.comm) 11353 atomic_inc(&nr_comm_events); 11354 if (event->attr.namespaces) 11355 atomic_inc(&nr_namespaces_events); 11356 if (event->attr.cgroup) 11357 atomic_inc(&nr_cgroup_events); 11358 if (event->attr.task) 11359 atomic_inc(&nr_task_events); 11360 if (event->attr.freq) 11361 account_freq_event(); 11362 if (event->attr.context_switch) { 11363 atomic_inc(&nr_switch_events); 11364 inc = true; 11365 } 11366 if (has_branch_stack(event)) 11367 inc = true; 11368 if (is_cgroup_event(event)) 11369 inc = true; 11370 if (event->attr.ksymbol) 11371 atomic_inc(&nr_ksymbol_events); 11372 if (event->attr.bpf_event) 11373 atomic_inc(&nr_bpf_events); 11374 if (event->attr.text_poke) 11375 atomic_inc(&nr_text_poke_events); 11376 11377 if (inc) { 11378 /* 11379 * We need the mutex here because static_branch_enable() 11380 * must complete *before* the perf_sched_count increment 11381 * becomes visible. 11382 */ 11383 if (atomic_inc_not_zero(&perf_sched_count)) 11384 goto enabled; 11385 11386 mutex_lock(&perf_sched_mutex); 11387 if (!atomic_read(&perf_sched_count)) { 11388 static_branch_enable(&perf_sched_events); 11389 /* 11390 * Guarantee that all CPUs observe they key change and 11391 * call the perf scheduling hooks before proceeding to 11392 * install events that need them. 11393 */ 11394 synchronize_rcu(); 11395 } 11396 /* 11397 * Now that we have waited for the sync_sched(), allow further 11398 * increments to by-pass the mutex. 11399 */ 11400 atomic_inc(&perf_sched_count); 11401 mutex_unlock(&perf_sched_mutex); 11402 } 11403 enabled: 11404 11405 account_event_cpu(event, event->cpu); 11406 11407 account_pmu_sb_event(event); 11408 } 11409 11410 /* 11411 * Allocate and initialize an event structure 11412 */ 11413 static struct perf_event * 11414 perf_event_alloc(struct perf_event_attr *attr, int cpu, 11415 struct task_struct *task, 11416 struct perf_event *group_leader, 11417 struct perf_event *parent_event, 11418 perf_overflow_handler_t overflow_handler, 11419 void *context, int cgroup_fd) 11420 { 11421 struct pmu *pmu; 11422 struct perf_event *event; 11423 struct hw_perf_event *hwc; 11424 long err = -EINVAL; 11425 int node; 11426 11427 if ((unsigned)cpu >= nr_cpu_ids) { 11428 if (!task || cpu != -1) 11429 return ERR_PTR(-EINVAL); 11430 } 11431 if (attr->sigtrap && !task) { 11432 /* Requires a task: avoid signalling random tasks. */ 11433 return ERR_PTR(-EINVAL); 11434 } 11435 11436 node = (cpu >= 0) ? cpu_to_node(cpu) : -1; 11437 event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO, 11438 node); 11439 if (!event) 11440 return ERR_PTR(-ENOMEM); 11441 11442 /* 11443 * Single events are their own group leaders, with an 11444 * empty sibling list: 11445 */ 11446 if (!group_leader) 11447 group_leader = event; 11448 11449 mutex_init(&event->child_mutex); 11450 INIT_LIST_HEAD(&event->child_list); 11451 11452 INIT_LIST_HEAD(&event->event_entry); 11453 INIT_LIST_HEAD(&event->sibling_list); 11454 INIT_LIST_HEAD(&event->active_list); 11455 init_event_group(event); 11456 INIT_LIST_HEAD(&event->rb_entry); 11457 INIT_LIST_HEAD(&event->active_entry); 11458 INIT_LIST_HEAD(&event->addr_filters.list); 11459 INIT_HLIST_NODE(&event->hlist_entry); 11460 11461 11462 init_waitqueue_head(&event->waitq); 11463 event->pending_disable = -1; 11464 init_irq_work(&event->pending, perf_pending_event); 11465 11466 mutex_init(&event->mmap_mutex); 11467 raw_spin_lock_init(&event->addr_filters.lock); 11468 11469 atomic_long_set(&event->refcount, 1); 11470 event->cpu = cpu; 11471 event->attr = *attr; 11472 event->group_leader = group_leader; 11473 event->pmu = NULL; 11474 event->oncpu = -1; 11475 11476 event->parent = parent_event; 11477 11478 event->ns = get_pid_ns(task_active_pid_ns(current)); 11479 event->id = atomic64_inc_return(&perf_event_id); 11480 11481 event->state = PERF_EVENT_STATE_INACTIVE; 11482 11483 if (event->attr.sigtrap) 11484 atomic_set(&event->event_limit, 1); 11485 11486 if (task) { 11487 event->attach_state = PERF_ATTACH_TASK; 11488 /* 11489 * XXX pmu::event_init needs to know what task to account to 11490 * and we cannot use the ctx information because we need the 11491 * pmu before we get a ctx. 11492 */ 11493 event->hw.target = get_task_struct(task); 11494 } 11495 11496 event->clock = &local_clock; 11497 if (parent_event) 11498 event->clock = parent_event->clock; 11499 11500 if (!overflow_handler && parent_event) { 11501 overflow_handler = parent_event->overflow_handler; 11502 context = parent_event->overflow_handler_context; 11503 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING) 11504 if (overflow_handler == bpf_overflow_handler) { 11505 struct bpf_prog *prog = parent_event->prog; 11506 11507 bpf_prog_inc(prog); 11508 event->prog = prog; 11509 event->orig_overflow_handler = 11510 parent_event->orig_overflow_handler; 11511 } 11512 #endif 11513 } 11514 11515 if (overflow_handler) { 11516 event->overflow_handler = overflow_handler; 11517 event->overflow_handler_context = context; 11518 } else if (is_write_backward(event)){ 11519 event->overflow_handler = perf_event_output_backward; 11520 event->overflow_handler_context = NULL; 11521 } else { 11522 event->overflow_handler = perf_event_output_forward; 11523 event->overflow_handler_context = NULL; 11524 } 11525 11526 perf_event__state_init(event); 11527 11528 pmu = NULL; 11529 11530 hwc = &event->hw; 11531 hwc->sample_period = attr->sample_period; 11532 if (attr->freq && attr->sample_freq) 11533 hwc->sample_period = 1; 11534 hwc->last_period = hwc->sample_period; 11535 11536 local64_set(&hwc->period_left, hwc->sample_period); 11537 11538 /* 11539 * We currently do not support PERF_SAMPLE_READ on inherited events. 11540 * See perf_output_read(). 11541 */ 11542 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ)) 11543 goto err_ns; 11544 11545 if (!has_branch_stack(event)) 11546 event->attr.branch_sample_type = 0; 11547 11548 pmu = perf_init_event(event); 11549 if (IS_ERR(pmu)) { 11550 err = PTR_ERR(pmu); 11551 goto err_ns; 11552 } 11553 11554 /* 11555 * Disallow uncore-cgroup events, they don't make sense as the cgroup will 11556 * be different on other CPUs in the uncore mask. 11557 */ 11558 if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) { 11559 err = -EINVAL; 11560 goto err_pmu; 11561 } 11562 11563 if (event->attr.aux_output && 11564 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) { 11565 err = -EOPNOTSUPP; 11566 goto err_pmu; 11567 } 11568 11569 if (cgroup_fd != -1) { 11570 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader); 11571 if (err) 11572 goto err_pmu; 11573 } 11574 11575 err = exclusive_event_init(event); 11576 if (err) 11577 goto err_pmu; 11578 11579 if (has_addr_filter(event)) { 11580 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters, 11581 sizeof(struct perf_addr_filter_range), 11582 GFP_KERNEL); 11583 if (!event->addr_filter_ranges) { 11584 err = -ENOMEM; 11585 goto err_per_task; 11586 } 11587 11588 /* 11589 * Clone the parent's vma offsets: they are valid until exec() 11590 * even if the mm is not shared with the parent. 11591 */ 11592 if (event->parent) { 11593 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 11594 11595 raw_spin_lock_irq(&ifh->lock); 11596 memcpy(event->addr_filter_ranges, 11597 event->parent->addr_filter_ranges, 11598 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range)); 11599 raw_spin_unlock_irq(&ifh->lock); 11600 } 11601 11602 /* force hw sync on the address filters */ 11603 event->addr_filters_gen = 1; 11604 } 11605 11606 if (!event->parent) { 11607 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) { 11608 err = get_callchain_buffers(attr->sample_max_stack); 11609 if (err) 11610 goto err_addr_filters; 11611 } 11612 } 11613 11614 err = security_perf_event_alloc(event); 11615 if (err) 11616 goto err_callchain_buffer; 11617 11618 /* symmetric to unaccount_event() in _free_event() */ 11619 account_event(event); 11620 11621 return event; 11622 11623 err_callchain_buffer: 11624 if (!event->parent) { 11625 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) 11626 put_callchain_buffers(); 11627 } 11628 err_addr_filters: 11629 kfree(event->addr_filter_ranges); 11630 11631 err_per_task: 11632 exclusive_event_destroy(event); 11633 11634 err_pmu: 11635 if (is_cgroup_event(event)) 11636 perf_detach_cgroup(event); 11637 if (event->destroy) 11638 event->destroy(event); 11639 module_put(pmu->module); 11640 err_ns: 11641 if (event->ns) 11642 put_pid_ns(event->ns); 11643 if (event->hw.target) 11644 put_task_struct(event->hw.target); 11645 kmem_cache_free(perf_event_cache, event); 11646 11647 return ERR_PTR(err); 11648 } 11649 11650 static int perf_copy_attr(struct perf_event_attr __user *uattr, 11651 struct perf_event_attr *attr) 11652 { 11653 u32 size; 11654 int ret; 11655 11656 /* Zero the full structure, so that a short copy will be nice. */ 11657 memset(attr, 0, sizeof(*attr)); 11658 11659 ret = get_user(size, &uattr->size); 11660 if (ret) 11661 return ret; 11662 11663 /* ABI compatibility quirk: */ 11664 if (!size) 11665 size = PERF_ATTR_SIZE_VER0; 11666 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE) 11667 goto err_size; 11668 11669 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size); 11670 if (ret) { 11671 if (ret == -E2BIG) 11672 goto err_size; 11673 return ret; 11674 } 11675 11676 attr->size = size; 11677 11678 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3) 11679 return -EINVAL; 11680 11681 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1)) 11682 return -EINVAL; 11683 11684 if (attr->read_format & ~(PERF_FORMAT_MAX-1)) 11685 return -EINVAL; 11686 11687 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) { 11688 u64 mask = attr->branch_sample_type; 11689 11690 /* only using defined bits */ 11691 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1)) 11692 return -EINVAL; 11693 11694 /* at least one branch bit must be set */ 11695 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL)) 11696 return -EINVAL; 11697 11698 /* propagate priv level, when not set for branch */ 11699 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) { 11700 11701 /* exclude_kernel checked on syscall entry */ 11702 if (!attr->exclude_kernel) 11703 mask |= PERF_SAMPLE_BRANCH_KERNEL; 11704 11705 if (!attr->exclude_user) 11706 mask |= PERF_SAMPLE_BRANCH_USER; 11707 11708 if (!attr->exclude_hv) 11709 mask |= PERF_SAMPLE_BRANCH_HV; 11710 /* 11711 * adjust user setting (for HW filter setup) 11712 */ 11713 attr->branch_sample_type = mask; 11714 } 11715 /* privileged levels capture (kernel, hv): check permissions */ 11716 if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) { 11717 ret = perf_allow_kernel(attr); 11718 if (ret) 11719 return ret; 11720 } 11721 } 11722 11723 if (attr->sample_type & PERF_SAMPLE_REGS_USER) { 11724 ret = perf_reg_validate(attr->sample_regs_user); 11725 if (ret) 11726 return ret; 11727 } 11728 11729 if (attr->sample_type & PERF_SAMPLE_STACK_USER) { 11730 if (!arch_perf_have_user_stack_dump()) 11731 return -ENOSYS; 11732 11733 /* 11734 * We have __u32 type for the size, but so far 11735 * we can only use __u16 as maximum due to the 11736 * __u16 sample size limit. 11737 */ 11738 if (attr->sample_stack_user >= USHRT_MAX) 11739 return -EINVAL; 11740 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64))) 11741 return -EINVAL; 11742 } 11743 11744 if (!attr->sample_max_stack) 11745 attr->sample_max_stack = sysctl_perf_event_max_stack; 11746 11747 if (attr->sample_type & PERF_SAMPLE_REGS_INTR) 11748 ret = perf_reg_validate(attr->sample_regs_intr); 11749 11750 #ifndef CONFIG_CGROUP_PERF 11751 if (attr->sample_type & PERF_SAMPLE_CGROUP) 11752 return -EINVAL; 11753 #endif 11754 if ((attr->sample_type & PERF_SAMPLE_WEIGHT) && 11755 (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT)) 11756 return -EINVAL; 11757 11758 if (!attr->inherit && attr->inherit_thread) 11759 return -EINVAL; 11760 11761 if (attr->remove_on_exec && attr->enable_on_exec) 11762 return -EINVAL; 11763 11764 if (attr->sigtrap && !attr->remove_on_exec) 11765 return -EINVAL; 11766 11767 out: 11768 return ret; 11769 11770 err_size: 11771 put_user(sizeof(*attr), &uattr->size); 11772 ret = -E2BIG; 11773 goto out; 11774 } 11775 11776 static int 11777 perf_event_set_output(struct perf_event *event, struct perf_event *output_event) 11778 { 11779 struct perf_buffer *rb = NULL; 11780 int ret = -EINVAL; 11781 11782 if (!output_event) 11783 goto set; 11784 11785 /* don't allow circular references */ 11786 if (event == output_event) 11787 goto out; 11788 11789 /* 11790 * Don't allow cross-cpu buffers 11791 */ 11792 if (output_event->cpu != event->cpu) 11793 goto out; 11794 11795 /* 11796 * If its not a per-cpu rb, it must be the same task. 11797 */ 11798 if (output_event->cpu == -1 && output_event->ctx != event->ctx) 11799 goto out; 11800 11801 /* 11802 * Mixing clocks in the same buffer is trouble you don't need. 11803 */ 11804 if (output_event->clock != event->clock) 11805 goto out; 11806 11807 /* 11808 * Either writing ring buffer from beginning or from end. 11809 * Mixing is not allowed. 11810 */ 11811 if (is_write_backward(output_event) != is_write_backward(event)) 11812 goto out; 11813 11814 /* 11815 * If both events generate aux data, they must be on the same PMU 11816 */ 11817 if (has_aux(event) && has_aux(output_event) && 11818 event->pmu != output_event->pmu) 11819 goto out; 11820 11821 set: 11822 mutex_lock(&event->mmap_mutex); 11823 /* Can't redirect output if we've got an active mmap() */ 11824 if (atomic_read(&event->mmap_count)) 11825 goto unlock; 11826 11827 if (output_event) { 11828 /* get the rb we want to redirect to */ 11829 rb = ring_buffer_get(output_event); 11830 if (!rb) 11831 goto unlock; 11832 } 11833 11834 ring_buffer_attach(event, rb); 11835 11836 ret = 0; 11837 unlock: 11838 mutex_unlock(&event->mmap_mutex); 11839 11840 out: 11841 return ret; 11842 } 11843 11844 static void mutex_lock_double(struct mutex *a, struct mutex *b) 11845 { 11846 if (b < a) 11847 swap(a, b); 11848 11849 mutex_lock(a); 11850 mutex_lock_nested(b, SINGLE_DEPTH_NESTING); 11851 } 11852 11853 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id) 11854 { 11855 bool nmi_safe = false; 11856 11857 switch (clk_id) { 11858 case CLOCK_MONOTONIC: 11859 event->clock = &ktime_get_mono_fast_ns; 11860 nmi_safe = true; 11861 break; 11862 11863 case CLOCK_MONOTONIC_RAW: 11864 event->clock = &ktime_get_raw_fast_ns; 11865 nmi_safe = true; 11866 break; 11867 11868 case CLOCK_REALTIME: 11869 event->clock = &ktime_get_real_ns; 11870 break; 11871 11872 case CLOCK_BOOTTIME: 11873 event->clock = &ktime_get_boottime_ns; 11874 break; 11875 11876 case CLOCK_TAI: 11877 event->clock = &ktime_get_clocktai_ns; 11878 break; 11879 11880 default: 11881 return -EINVAL; 11882 } 11883 11884 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI)) 11885 return -EINVAL; 11886 11887 return 0; 11888 } 11889 11890 /* 11891 * Variation on perf_event_ctx_lock_nested(), except we take two context 11892 * mutexes. 11893 */ 11894 static struct perf_event_context * 11895 __perf_event_ctx_lock_double(struct perf_event *group_leader, 11896 struct perf_event_context *ctx) 11897 { 11898 struct perf_event_context *gctx; 11899 11900 again: 11901 rcu_read_lock(); 11902 gctx = READ_ONCE(group_leader->ctx); 11903 if (!refcount_inc_not_zero(&gctx->refcount)) { 11904 rcu_read_unlock(); 11905 goto again; 11906 } 11907 rcu_read_unlock(); 11908 11909 mutex_lock_double(&gctx->mutex, &ctx->mutex); 11910 11911 if (group_leader->ctx != gctx) { 11912 mutex_unlock(&ctx->mutex); 11913 mutex_unlock(&gctx->mutex); 11914 put_ctx(gctx); 11915 goto again; 11916 } 11917 11918 return gctx; 11919 } 11920 11921 static bool 11922 perf_check_permission(struct perf_event_attr *attr, struct task_struct *task) 11923 { 11924 unsigned int ptrace_mode = PTRACE_MODE_READ_REALCREDS; 11925 bool is_capable = perfmon_capable(); 11926 11927 if (attr->sigtrap) { 11928 /* 11929 * perf_event_attr::sigtrap sends signals to the other task. 11930 * Require the current task to also have CAP_KILL. 11931 */ 11932 rcu_read_lock(); 11933 is_capable &= ns_capable(__task_cred(task)->user_ns, CAP_KILL); 11934 rcu_read_unlock(); 11935 11936 /* 11937 * If the required capabilities aren't available, checks for 11938 * ptrace permissions: upgrade to ATTACH, since sending signals 11939 * can effectively change the target task. 11940 */ 11941 ptrace_mode = PTRACE_MODE_ATTACH_REALCREDS; 11942 } 11943 11944 /* 11945 * Preserve ptrace permission check for backwards compatibility. The 11946 * ptrace check also includes checks that the current task and other 11947 * task have matching uids, and is therefore not done here explicitly. 11948 */ 11949 return is_capable || ptrace_may_access(task, ptrace_mode); 11950 } 11951 11952 /** 11953 * sys_perf_event_open - open a performance event, associate it to a task/cpu 11954 * 11955 * @attr_uptr: event_id type attributes for monitoring/sampling 11956 * @pid: target pid 11957 * @cpu: target cpu 11958 * @group_fd: group leader event fd 11959 * @flags: perf event open flags 11960 */ 11961 SYSCALL_DEFINE5(perf_event_open, 11962 struct perf_event_attr __user *, attr_uptr, 11963 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags) 11964 { 11965 struct perf_event *group_leader = NULL, *output_event = NULL; 11966 struct perf_event *event, *sibling; 11967 struct perf_event_attr attr; 11968 struct perf_event_context *ctx, *gctx; 11969 struct file *event_file = NULL; 11970 struct fd group = {NULL, 0}; 11971 struct task_struct *task = NULL; 11972 struct pmu *pmu; 11973 int event_fd; 11974 int move_group = 0; 11975 int err; 11976 int f_flags = O_RDWR; 11977 int cgroup_fd = -1; 11978 11979 /* for future expandability... */ 11980 if (flags & ~PERF_FLAG_ALL) 11981 return -EINVAL; 11982 11983 /* Do we allow access to perf_event_open(2) ? */ 11984 err = security_perf_event_open(&attr, PERF_SECURITY_OPEN); 11985 if (err) 11986 return err; 11987 11988 err = perf_copy_attr(attr_uptr, &attr); 11989 if (err) 11990 return err; 11991 11992 if (!attr.exclude_kernel) { 11993 err = perf_allow_kernel(&attr); 11994 if (err) 11995 return err; 11996 } 11997 11998 if (attr.namespaces) { 11999 if (!perfmon_capable()) 12000 return -EACCES; 12001 } 12002 12003 if (attr.freq) { 12004 if (attr.sample_freq > sysctl_perf_event_sample_rate) 12005 return -EINVAL; 12006 } else { 12007 if (attr.sample_period & (1ULL << 63)) 12008 return -EINVAL; 12009 } 12010 12011 /* Only privileged users can get physical addresses */ 12012 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) { 12013 err = perf_allow_kernel(&attr); 12014 if (err) 12015 return err; 12016 } 12017 12018 /* REGS_INTR can leak data, lockdown must prevent this */ 12019 if (attr.sample_type & PERF_SAMPLE_REGS_INTR) { 12020 err = security_locked_down(LOCKDOWN_PERF); 12021 if (err) 12022 return err; 12023 } 12024 12025 /* 12026 * In cgroup mode, the pid argument is used to pass the fd 12027 * opened to the cgroup directory in cgroupfs. The cpu argument 12028 * designates the cpu on which to monitor threads from that 12029 * cgroup. 12030 */ 12031 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1)) 12032 return -EINVAL; 12033 12034 if (flags & PERF_FLAG_FD_CLOEXEC) 12035 f_flags |= O_CLOEXEC; 12036 12037 event_fd = get_unused_fd_flags(f_flags); 12038 if (event_fd < 0) 12039 return event_fd; 12040 12041 if (group_fd != -1) { 12042 err = perf_fget_light(group_fd, &group); 12043 if (err) 12044 goto err_fd; 12045 group_leader = group.file->private_data; 12046 if (flags & PERF_FLAG_FD_OUTPUT) 12047 output_event = group_leader; 12048 if (flags & PERF_FLAG_FD_NO_GROUP) 12049 group_leader = NULL; 12050 } 12051 12052 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) { 12053 task = find_lively_task_by_vpid(pid); 12054 if (IS_ERR(task)) { 12055 err = PTR_ERR(task); 12056 goto err_group_fd; 12057 } 12058 } 12059 12060 if (task && group_leader && 12061 group_leader->attr.inherit != attr.inherit) { 12062 err = -EINVAL; 12063 goto err_task; 12064 } 12065 12066 if (flags & PERF_FLAG_PID_CGROUP) 12067 cgroup_fd = pid; 12068 12069 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, 12070 NULL, NULL, cgroup_fd); 12071 if (IS_ERR(event)) { 12072 err = PTR_ERR(event); 12073 goto err_task; 12074 } 12075 12076 if (is_sampling_event(event)) { 12077 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) { 12078 err = -EOPNOTSUPP; 12079 goto err_alloc; 12080 } 12081 } 12082 12083 /* 12084 * Special case software events and allow them to be part of 12085 * any hardware group. 12086 */ 12087 pmu = event->pmu; 12088 12089 if (attr.use_clockid) { 12090 err = perf_event_set_clock(event, attr.clockid); 12091 if (err) 12092 goto err_alloc; 12093 } 12094 12095 if (pmu->task_ctx_nr == perf_sw_context) 12096 event->event_caps |= PERF_EV_CAP_SOFTWARE; 12097 12098 if (group_leader) { 12099 if (is_software_event(event) && 12100 !in_software_context(group_leader)) { 12101 /* 12102 * If the event is a sw event, but the group_leader 12103 * is on hw context. 12104 * 12105 * Allow the addition of software events to hw 12106 * groups, this is safe because software events 12107 * never fail to schedule. 12108 */ 12109 pmu = group_leader->ctx->pmu; 12110 } else if (!is_software_event(event) && 12111 is_software_event(group_leader) && 12112 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) { 12113 /* 12114 * In case the group is a pure software group, and we 12115 * try to add a hardware event, move the whole group to 12116 * the hardware context. 12117 */ 12118 move_group = 1; 12119 } 12120 } 12121 12122 /* 12123 * Get the target context (task or percpu): 12124 */ 12125 ctx = find_get_context(pmu, task, event); 12126 if (IS_ERR(ctx)) { 12127 err = PTR_ERR(ctx); 12128 goto err_alloc; 12129 } 12130 12131 /* 12132 * Look up the group leader (we will attach this event to it): 12133 */ 12134 if (group_leader) { 12135 err = -EINVAL; 12136 12137 /* 12138 * Do not allow a recursive hierarchy (this new sibling 12139 * becoming part of another group-sibling): 12140 */ 12141 if (group_leader->group_leader != group_leader) 12142 goto err_context; 12143 12144 /* All events in a group should have the same clock */ 12145 if (group_leader->clock != event->clock) 12146 goto err_context; 12147 12148 /* 12149 * Make sure we're both events for the same CPU; 12150 * grouping events for different CPUs is broken; since 12151 * you can never concurrently schedule them anyhow. 12152 */ 12153 if (group_leader->cpu != event->cpu) 12154 goto err_context; 12155 12156 /* 12157 * Make sure we're both on the same task, or both 12158 * per-CPU events. 12159 */ 12160 if (group_leader->ctx->task != ctx->task) 12161 goto err_context; 12162 12163 /* 12164 * Do not allow to attach to a group in a different task 12165 * or CPU context. If we're moving SW events, we'll fix 12166 * this up later, so allow that. 12167 */ 12168 if (!move_group && group_leader->ctx != ctx) 12169 goto err_context; 12170 12171 /* 12172 * Only a group leader can be exclusive or pinned 12173 */ 12174 if (attr.exclusive || attr.pinned) 12175 goto err_context; 12176 } 12177 12178 if (output_event) { 12179 err = perf_event_set_output(event, output_event); 12180 if (err) 12181 goto err_context; 12182 } 12183 12184 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, 12185 f_flags); 12186 if (IS_ERR(event_file)) { 12187 err = PTR_ERR(event_file); 12188 event_file = NULL; 12189 goto err_context; 12190 } 12191 12192 if (task) { 12193 err = down_read_interruptible(&task->signal->exec_update_lock); 12194 if (err) 12195 goto err_file; 12196 12197 /* 12198 * We must hold exec_update_lock across this and any potential 12199 * perf_install_in_context() call for this new event to 12200 * serialize against exec() altering our credentials (and the 12201 * perf_event_exit_task() that could imply). 12202 */ 12203 err = -EACCES; 12204 if (!perf_check_permission(&attr, task)) 12205 goto err_cred; 12206 } 12207 12208 if (move_group) { 12209 gctx = __perf_event_ctx_lock_double(group_leader, ctx); 12210 12211 if (gctx->task == TASK_TOMBSTONE) { 12212 err = -ESRCH; 12213 goto err_locked; 12214 } 12215 12216 /* 12217 * Check if we raced against another sys_perf_event_open() call 12218 * moving the software group underneath us. 12219 */ 12220 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) { 12221 /* 12222 * If someone moved the group out from under us, check 12223 * if this new event wound up on the same ctx, if so 12224 * its the regular !move_group case, otherwise fail. 12225 */ 12226 if (gctx != ctx) { 12227 err = -EINVAL; 12228 goto err_locked; 12229 } else { 12230 perf_event_ctx_unlock(group_leader, gctx); 12231 move_group = 0; 12232 } 12233 } 12234 12235 /* 12236 * Failure to create exclusive events returns -EBUSY. 12237 */ 12238 err = -EBUSY; 12239 if (!exclusive_event_installable(group_leader, ctx)) 12240 goto err_locked; 12241 12242 for_each_sibling_event(sibling, group_leader) { 12243 if (!exclusive_event_installable(sibling, ctx)) 12244 goto err_locked; 12245 } 12246 } else { 12247 mutex_lock(&ctx->mutex); 12248 } 12249 12250 if (ctx->task == TASK_TOMBSTONE) { 12251 err = -ESRCH; 12252 goto err_locked; 12253 } 12254 12255 if (!perf_event_validate_size(event)) { 12256 err = -E2BIG; 12257 goto err_locked; 12258 } 12259 12260 if (!task) { 12261 /* 12262 * Check if the @cpu we're creating an event for is online. 12263 * 12264 * We use the perf_cpu_context::ctx::mutex to serialize against 12265 * the hotplug notifiers. See perf_event_{init,exit}_cpu(). 12266 */ 12267 struct perf_cpu_context *cpuctx = 12268 container_of(ctx, struct perf_cpu_context, ctx); 12269 12270 if (!cpuctx->online) { 12271 err = -ENODEV; 12272 goto err_locked; 12273 } 12274 } 12275 12276 if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) { 12277 err = -EINVAL; 12278 goto err_locked; 12279 } 12280 12281 /* 12282 * Must be under the same ctx::mutex as perf_install_in_context(), 12283 * because we need to serialize with concurrent event creation. 12284 */ 12285 if (!exclusive_event_installable(event, ctx)) { 12286 err = -EBUSY; 12287 goto err_locked; 12288 } 12289 12290 WARN_ON_ONCE(ctx->parent_ctx); 12291 12292 /* 12293 * This is the point on no return; we cannot fail hereafter. This is 12294 * where we start modifying current state. 12295 */ 12296 12297 if (move_group) { 12298 /* 12299 * See perf_event_ctx_lock() for comments on the details 12300 * of swizzling perf_event::ctx. 12301 */ 12302 perf_remove_from_context(group_leader, 0); 12303 put_ctx(gctx); 12304 12305 for_each_sibling_event(sibling, group_leader) { 12306 perf_remove_from_context(sibling, 0); 12307 put_ctx(gctx); 12308 } 12309 12310 /* 12311 * Wait for everybody to stop referencing the events through 12312 * the old lists, before installing it on new lists. 12313 */ 12314 synchronize_rcu(); 12315 12316 /* 12317 * Install the group siblings before the group leader. 12318 * 12319 * Because a group leader will try and install the entire group 12320 * (through the sibling list, which is still in-tact), we can 12321 * end up with siblings installed in the wrong context. 12322 * 12323 * By installing siblings first we NO-OP because they're not 12324 * reachable through the group lists. 12325 */ 12326 for_each_sibling_event(sibling, group_leader) { 12327 perf_event__state_init(sibling); 12328 perf_install_in_context(ctx, sibling, sibling->cpu); 12329 get_ctx(ctx); 12330 } 12331 12332 /* 12333 * Removing from the context ends up with disabled 12334 * event. What we want here is event in the initial 12335 * startup state, ready to be add into new context. 12336 */ 12337 perf_event__state_init(group_leader); 12338 perf_install_in_context(ctx, group_leader, group_leader->cpu); 12339 get_ctx(ctx); 12340 } 12341 12342 /* 12343 * Precalculate sample_data sizes; do while holding ctx::mutex such 12344 * that we're serialized against further additions and before 12345 * perf_install_in_context() which is the point the event is active and 12346 * can use these values. 12347 */ 12348 perf_event__header_size(event); 12349 perf_event__id_header_size(event); 12350 12351 event->owner = current; 12352 12353 perf_install_in_context(ctx, event, event->cpu); 12354 perf_unpin_context(ctx); 12355 12356 if (move_group) 12357 perf_event_ctx_unlock(group_leader, gctx); 12358 mutex_unlock(&ctx->mutex); 12359 12360 if (task) { 12361 up_read(&task->signal->exec_update_lock); 12362 put_task_struct(task); 12363 } 12364 12365 mutex_lock(¤t->perf_event_mutex); 12366 list_add_tail(&event->owner_entry, ¤t->perf_event_list); 12367 mutex_unlock(¤t->perf_event_mutex); 12368 12369 /* 12370 * Drop the reference on the group_event after placing the 12371 * new event on the sibling_list. This ensures destruction 12372 * of the group leader will find the pointer to itself in 12373 * perf_group_detach(). 12374 */ 12375 fdput(group); 12376 fd_install(event_fd, event_file); 12377 return event_fd; 12378 12379 err_locked: 12380 if (move_group) 12381 perf_event_ctx_unlock(group_leader, gctx); 12382 mutex_unlock(&ctx->mutex); 12383 err_cred: 12384 if (task) 12385 up_read(&task->signal->exec_update_lock); 12386 err_file: 12387 fput(event_file); 12388 err_context: 12389 perf_unpin_context(ctx); 12390 put_ctx(ctx); 12391 err_alloc: 12392 /* 12393 * If event_file is set, the fput() above will have called ->release() 12394 * and that will take care of freeing the event. 12395 */ 12396 if (!event_file) 12397 free_event(event); 12398 err_task: 12399 if (task) 12400 put_task_struct(task); 12401 err_group_fd: 12402 fdput(group); 12403 err_fd: 12404 put_unused_fd(event_fd); 12405 return err; 12406 } 12407 12408 /** 12409 * perf_event_create_kernel_counter 12410 * 12411 * @attr: attributes of the counter to create 12412 * @cpu: cpu in which the counter is bound 12413 * @task: task to profile (NULL for percpu) 12414 * @overflow_handler: callback to trigger when we hit the event 12415 * @context: context data could be used in overflow_handler callback 12416 */ 12417 struct perf_event * 12418 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, 12419 struct task_struct *task, 12420 perf_overflow_handler_t overflow_handler, 12421 void *context) 12422 { 12423 struct perf_event_context *ctx; 12424 struct perf_event *event; 12425 int err; 12426 12427 /* 12428 * Grouping is not supported for kernel events, neither is 'AUX', 12429 * make sure the caller's intentions are adjusted. 12430 */ 12431 if (attr->aux_output) 12432 return ERR_PTR(-EINVAL); 12433 12434 event = perf_event_alloc(attr, cpu, task, NULL, NULL, 12435 overflow_handler, context, -1); 12436 if (IS_ERR(event)) { 12437 err = PTR_ERR(event); 12438 goto err; 12439 } 12440 12441 /* Mark owner so we could distinguish it from user events. */ 12442 event->owner = TASK_TOMBSTONE; 12443 12444 /* 12445 * Get the target context (task or percpu): 12446 */ 12447 ctx = find_get_context(event->pmu, task, event); 12448 if (IS_ERR(ctx)) { 12449 err = PTR_ERR(ctx); 12450 goto err_free; 12451 } 12452 12453 WARN_ON_ONCE(ctx->parent_ctx); 12454 mutex_lock(&ctx->mutex); 12455 if (ctx->task == TASK_TOMBSTONE) { 12456 err = -ESRCH; 12457 goto err_unlock; 12458 } 12459 12460 if (!task) { 12461 /* 12462 * Check if the @cpu we're creating an event for is online. 12463 * 12464 * We use the perf_cpu_context::ctx::mutex to serialize against 12465 * the hotplug notifiers. See perf_event_{init,exit}_cpu(). 12466 */ 12467 struct perf_cpu_context *cpuctx = 12468 container_of(ctx, struct perf_cpu_context, ctx); 12469 if (!cpuctx->online) { 12470 err = -ENODEV; 12471 goto err_unlock; 12472 } 12473 } 12474 12475 if (!exclusive_event_installable(event, ctx)) { 12476 err = -EBUSY; 12477 goto err_unlock; 12478 } 12479 12480 perf_install_in_context(ctx, event, event->cpu); 12481 perf_unpin_context(ctx); 12482 mutex_unlock(&ctx->mutex); 12483 12484 return event; 12485 12486 err_unlock: 12487 mutex_unlock(&ctx->mutex); 12488 perf_unpin_context(ctx); 12489 put_ctx(ctx); 12490 err_free: 12491 free_event(event); 12492 err: 12493 return ERR_PTR(err); 12494 } 12495 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter); 12496 12497 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu) 12498 { 12499 struct perf_event_context *src_ctx; 12500 struct perf_event_context *dst_ctx; 12501 struct perf_event *event, *tmp; 12502 LIST_HEAD(events); 12503 12504 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx; 12505 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx; 12506 12507 /* 12508 * See perf_event_ctx_lock() for comments on the details 12509 * of swizzling perf_event::ctx. 12510 */ 12511 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex); 12512 list_for_each_entry_safe(event, tmp, &src_ctx->event_list, 12513 event_entry) { 12514 perf_remove_from_context(event, 0); 12515 unaccount_event_cpu(event, src_cpu); 12516 put_ctx(src_ctx); 12517 list_add(&event->migrate_entry, &events); 12518 } 12519 12520 /* 12521 * Wait for the events to quiesce before re-instating them. 12522 */ 12523 synchronize_rcu(); 12524 12525 /* 12526 * Re-instate events in 2 passes. 12527 * 12528 * Skip over group leaders and only install siblings on this first 12529 * pass, siblings will not get enabled without a leader, however a 12530 * leader will enable its siblings, even if those are still on the old 12531 * context. 12532 */ 12533 list_for_each_entry_safe(event, tmp, &events, migrate_entry) { 12534 if (event->group_leader == event) 12535 continue; 12536 12537 list_del(&event->migrate_entry); 12538 if (event->state >= PERF_EVENT_STATE_OFF) 12539 event->state = PERF_EVENT_STATE_INACTIVE; 12540 account_event_cpu(event, dst_cpu); 12541 perf_install_in_context(dst_ctx, event, dst_cpu); 12542 get_ctx(dst_ctx); 12543 } 12544 12545 /* 12546 * Once all the siblings are setup properly, install the group leaders 12547 * to make it go. 12548 */ 12549 list_for_each_entry_safe(event, tmp, &events, migrate_entry) { 12550 list_del(&event->migrate_entry); 12551 if (event->state >= PERF_EVENT_STATE_OFF) 12552 event->state = PERF_EVENT_STATE_INACTIVE; 12553 account_event_cpu(event, dst_cpu); 12554 perf_install_in_context(dst_ctx, event, dst_cpu); 12555 get_ctx(dst_ctx); 12556 } 12557 mutex_unlock(&dst_ctx->mutex); 12558 mutex_unlock(&src_ctx->mutex); 12559 } 12560 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context); 12561 12562 static void sync_child_event(struct perf_event *child_event) 12563 { 12564 struct perf_event *parent_event = child_event->parent; 12565 u64 child_val; 12566 12567 if (child_event->attr.inherit_stat) { 12568 struct task_struct *task = child_event->ctx->task; 12569 12570 if (task && task != TASK_TOMBSTONE) 12571 perf_event_read_event(child_event, task); 12572 } 12573 12574 child_val = perf_event_count(child_event); 12575 12576 /* 12577 * Add back the child's count to the parent's count: 12578 */ 12579 atomic64_add(child_val, &parent_event->child_count); 12580 atomic64_add(child_event->total_time_enabled, 12581 &parent_event->child_total_time_enabled); 12582 atomic64_add(child_event->total_time_running, 12583 &parent_event->child_total_time_running); 12584 } 12585 12586 static void 12587 perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx) 12588 { 12589 struct perf_event *parent_event = event->parent; 12590 unsigned long detach_flags = 0; 12591 12592 if (parent_event) { 12593 /* 12594 * Do not destroy the 'original' grouping; because of the 12595 * context switch optimization the original events could've 12596 * ended up in a random child task. 12597 * 12598 * If we were to destroy the original group, all group related 12599 * operations would cease to function properly after this 12600 * random child dies. 12601 * 12602 * Do destroy all inherited groups, we don't care about those 12603 * and being thorough is better. 12604 */ 12605 detach_flags = DETACH_GROUP | DETACH_CHILD; 12606 mutex_lock(&parent_event->child_mutex); 12607 } 12608 12609 perf_remove_from_context(event, detach_flags); 12610 12611 raw_spin_lock_irq(&ctx->lock); 12612 if (event->state > PERF_EVENT_STATE_EXIT) 12613 perf_event_set_state(event, PERF_EVENT_STATE_EXIT); 12614 raw_spin_unlock_irq(&ctx->lock); 12615 12616 /* 12617 * Child events can be freed. 12618 */ 12619 if (parent_event) { 12620 mutex_unlock(&parent_event->child_mutex); 12621 /* 12622 * Kick perf_poll() for is_event_hup(); 12623 */ 12624 perf_event_wakeup(parent_event); 12625 free_event(event); 12626 put_event(parent_event); 12627 return; 12628 } 12629 12630 /* 12631 * Parent events are governed by their filedesc, retain them. 12632 */ 12633 perf_event_wakeup(event); 12634 } 12635 12636 static void perf_event_exit_task_context(struct task_struct *child, int ctxn) 12637 { 12638 struct perf_event_context *child_ctx, *clone_ctx = NULL; 12639 struct perf_event *child_event, *next; 12640 12641 WARN_ON_ONCE(child != current); 12642 12643 child_ctx = perf_pin_task_context(child, ctxn); 12644 if (!child_ctx) 12645 return; 12646 12647 /* 12648 * In order to reduce the amount of tricky in ctx tear-down, we hold 12649 * ctx::mutex over the entire thing. This serializes against almost 12650 * everything that wants to access the ctx. 12651 * 12652 * The exception is sys_perf_event_open() / 12653 * perf_event_create_kernel_count() which does find_get_context() 12654 * without ctx::mutex (it cannot because of the move_group double mutex 12655 * lock thing). See the comments in perf_install_in_context(). 12656 */ 12657 mutex_lock(&child_ctx->mutex); 12658 12659 /* 12660 * In a single ctx::lock section, de-schedule the events and detach the 12661 * context from the task such that we cannot ever get it scheduled back 12662 * in. 12663 */ 12664 raw_spin_lock_irq(&child_ctx->lock); 12665 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL); 12666 12667 /* 12668 * Now that the context is inactive, destroy the task <-> ctx relation 12669 * and mark the context dead. 12670 */ 12671 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL); 12672 put_ctx(child_ctx); /* cannot be last */ 12673 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE); 12674 put_task_struct(current); /* cannot be last */ 12675 12676 clone_ctx = unclone_ctx(child_ctx); 12677 raw_spin_unlock_irq(&child_ctx->lock); 12678 12679 if (clone_ctx) 12680 put_ctx(clone_ctx); 12681 12682 /* 12683 * Report the task dead after unscheduling the events so that we 12684 * won't get any samples after PERF_RECORD_EXIT. We can however still 12685 * get a few PERF_RECORD_READ events. 12686 */ 12687 perf_event_task(child, child_ctx, 0); 12688 12689 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry) 12690 perf_event_exit_event(child_event, child_ctx); 12691 12692 mutex_unlock(&child_ctx->mutex); 12693 12694 put_ctx(child_ctx); 12695 } 12696 12697 /* 12698 * When a child task exits, feed back event values to parent events. 12699 * 12700 * Can be called with exec_update_lock held when called from 12701 * setup_new_exec(). 12702 */ 12703 void perf_event_exit_task(struct task_struct *child) 12704 { 12705 struct perf_event *event, *tmp; 12706 int ctxn; 12707 12708 mutex_lock(&child->perf_event_mutex); 12709 list_for_each_entry_safe(event, tmp, &child->perf_event_list, 12710 owner_entry) { 12711 list_del_init(&event->owner_entry); 12712 12713 /* 12714 * Ensure the list deletion is visible before we clear 12715 * the owner, closes a race against perf_release() where 12716 * we need to serialize on the owner->perf_event_mutex. 12717 */ 12718 smp_store_release(&event->owner, NULL); 12719 } 12720 mutex_unlock(&child->perf_event_mutex); 12721 12722 for_each_task_context_nr(ctxn) 12723 perf_event_exit_task_context(child, ctxn); 12724 12725 /* 12726 * The perf_event_exit_task_context calls perf_event_task 12727 * with child's task_ctx, which generates EXIT events for 12728 * child contexts and sets child->perf_event_ctxp[] to NULL. 12729 * At this point we need to send EXIT events to cpu contexts. 12730 */ 12731 perf_event_task(child, NULL, 0); 12732 } 12733 12734 static void perf_free_event(struct perf_event *event, 12735 struct perf_event_context *ctx) 12736 { 12737 struct perf_event *parent = event->parent; 12738 12739 if (WARN_ON_ONCE(!parent)) 12740 return; 12741 12742 mutex_lock(&parent->child_mutex); 12743 list_del_init(&event->child_list); 12744 mutex_unlock(&parent->child_mutex); 12745 12746 put_event(parent); 12747 12748 raw_spin_lock_irq(&ctx->lock); 12749 perf_group_detach(event); 12750 list_del_event(event, ctx); 12751 raw_spin_unlock_irq(&ctx->lock); 12752 free_event(event); 12753 } 12754 12755 /* 12756 * Free a context as created by inheritance by perf_event_init_task() below, 12757 * used by fork() in case of fail. 12758 * 12759 * Even though the task has never lived, the context and events have been 12760 * exposed through the child_list, so we must take care tearing it all down. 12761 */ 12762 void perf_event_free_task(struct task_struct *task) 12763 { 12764 struct perf_event_context *ctx; 12765 struct perf_event *event, *tmp; 12766 int ctxn; 12767 12768 for_each_task_context_nr(ctxn) { 12769 ctx = task->perf_event_ctxp[ctxn]; 12770 if (!ctx) 12771 continue; 12772 12773 mutex_lock(&ctx->mutex); 12774 raw_spin_lock_irq(&ctx->lock); 12775 /* 12776 * Destroy the task <-> ctx relation and mark the context dead. 12777 * 12778 * This is important because even though the task hasn't been 12779 * exposed yet the context has been (through child_list). 12780 */ 12781 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL); 12782 WRITE_ONCE(ctx->task, TASK_TOMBSTONE); 12783 put_task_struct(task); /* cannot be last */ 12784 raw_spin_unlock_irq(&ctx->lock); 12785 12786 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) 12787 perf_free_event(event, ctx); 12788 12789 mutex_unlock(&ctx->mutex); 12790 12791 /* 12792 * perf_event_release_kernel() could've stolen some of our 12793 * child events and still have them on its free_list. In that 12794 * case we must wait for these events to have been freed (in 12795 * particular all their references to this task must've been 12796 * dropped). 12797 * 12798 * Without this copy_process() will unconditionally free this 12799 * task (irrespective of its reference count) and 12800 * _free_event()'s put_task_struct(event->hw.target) will be a 12801 * use-after-free. 12802 * 12803 * Wait for all events to drop their context reference. 12804 */ 12805 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1); 12806 put_ctx(ctx); /* must be last */ 12807 } 12808 } 12809 12810 void perf_event_delayed_put(struct task_struct *task) 12811 { 12812 int ctxn; 12813 12814 for_each_task_context_nr(ctxn) 12815 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]); 12816 } 12817 12818 struct file *perf_event_get(unsigned int fd) 12819 { 12820 struct file *file = fget(fd); 12821 if (!file) 12822 return ERR_PTR(-EBADF); 12823 12824 if (file->f_op != &perf_fops) { 12825 fput(file); 12826 return ERR_PTR(-EBADF); 12827 } 12828 12829 return file; 12830 } 12831 12832 const struct perf_event *perf_get_event(struct file *file) 12833 { 12834 if (file->f_op != &perf_fops) 12835 return ERR_PTR(-EINVAL); 12836 12837 return file->private_data; 12838 } 12839 12840 const struct perf_event_attr *perf_event_attrs(struct perf_event *event) 12841 { 12842 if (!event) 12843 return ERR_PTR(-EINVAL); 12844 12845 return &event->attr; 12846 } 12847 12848 /* 12849 * Inherit an event from parent task to child task. 12850 * 12851 * Returns: 12852 * - valid pointer on success 12853 * - NULL for orphaned events 12854 * - IS_ERR() on error 12855 */ 12856 static struct perf_event * 12857 inherit_event(struct perf_event *parent_event, 12858 struct task_struct *parent, 12859 struct perf_event_context *parent_ctx, 12860 struct task_struct *child, 12861 struct perf_event *group_leader, 12862 struct perf_event_context *child_ctx) 12863 { 12864 enum perf_event_state parent_state = parent_event->state; 12865 struct perf_event *child_event; 12866 unsigned long flags; 12867 12868 /* 12869 * Instead of creating recursive hierarchies of events, 12870 * we link inherited events back to the original parent, 12871 * which has a filp for sure, which we use as the reference 12872 * count: 12873 */ 12874 if (parent_event->parent) 12875 parent_event = parent_event->parent; 12876 12877 child_event = perf_event_alloc(&parent_event->attr, 12878 parent_event->cpu, 12879 child, 12880 group_leader, parent_event, 12881 NULL, NULL, -1); 12882 if (IS_ERR(child_event)) 12883 return child_event; 12884 12885 12886 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) && 12887 !child_ctx->task_ctx_data) { 12888 struct pmu *pmu = child_event->pmu; 12889 12890 child_ctx->task_ctx_data = alloc_task_ctx_data(pmu); 12891 if (!child_ctx->task_ctx_data) { 12892 free_event(child_event); 12893 return ERR_PTR(-ENOMEM); 12894 } 12895 } 12896 12897 /* 12898 * is_orphaned_event() and list_add_tail(&parent_event->child_list) 12899 * must be under the same lock in order to serialize against 12900 * perf_event_release_kernel(), such that either we must observe 12901 * is_orphaned_event() or they will observe us on the child_list. 12902 */ 12903 mutex_lock(&parent_event->child_mutex); 12904 if (is_orphaned_event(parent_event) || 12905 !atomic_long_inc_not_zero(&parent_event->refcount)) { 12906 mutex_unlock(&parent_event->child_mutex); 12907 /* task_ctx_data is freed with child_ctx */ 12908 free_event(child_event); 12909 return NULL; 12910 } 12911 12912 get_ctx(child_ctx); 12913 12914 /* 12915 * Make the child state follow the state of the parent event, 12916 * not its attr.disabled bit. We hold the parent's mutex, 12917 * so we won't race with perf_event_{en, dis}able_family. 12918 */ 12919 if (parent_state >= PERF_EVENT_STATE_INACTIVE) 12920 child_event->state = PERF_EVENT_STATE_INACTIVE; 12921 else 12922 child_event->state = PERF_EVENT_STATE_OFF; 12923 12924 if (parent_event->attr.freq) { 12925 u64 sample_period = parent_event->hw.sample_period; 12926 struct hw_perf_event *hwc = &child_event->hw; 12927 12928 hwc->sample_period = sample_period; 12929 hwc->last_period = sample_period; 12930 12931 local64_set(&hwc->period_left, sample_period); 12932 } 12933 12934 child_event->ctx = child_ctx; 12935 child_event->overflow_handler = parent_event->overflow_handler; 12936 child_event->overflow_handler_context 12937 = parent_event->overflow_handler_context; 12938 12939 /* 12940 * Precalculate sample_data sizes 12941 */ 12942 perf_event__header_size(child_event); 12943 perf_event__id_header_size(child_event); 12944 12945 /* 12946 * Link it up in the child's context: 12947 */ 12948 raw_spin_lock_irqsave(&child_ctx->lock, flags); 12949 add_event_to_ctx(child_event, child_ctx); 12950 child_event->attach_state |= PERF_ATTACH_CHILD; 12951 raw_spin_unlock_irqrestore(&child_ctx->lock, flags); 12952 12953 /* 12954 * Link this into the parent event's child list 12955 */ 12956 list_add_tail(&child_event->child_list, &parent_event->child_list); 12957 mutex_unlock(&parent_event->child_mutex); 12958 12959 return child_event; 12960 } 12961 12962 /* 12963 * Inherits an event group. 12964 * 12965 * This will quietly suppress orphaned events; !inherit_event() is not an error. 12966 * This matches with perf_event_release_kernel() removing all child events. 12967 * 12968 * Returns: 12969 * - 0 on success 12970 * - <0 on error 12971 */ 12972 static int inherit_group(struct perf_event *parent_event, 12973 struct task_struct *parent, 12974 struct perf_event_context *parent_ctx, 12975 struct task_struct *child, 12976 struct perf_event_context *child_ctx) 12977 { 12978 struct perf_event *leader; 12979 struct perf_event *sub; 12980 struct perf_event *child_ctr; 12981 12982 leader = inherit_event(parent_event, parent, parent_ctx, 12983 child, NULL, child_ctx); 12984 if (IS_ERR(leader)) 12985 return PTR_ERR(leader); 12986 /* 12987 * @leader can be NULL here because of is_orphaned_event(). In this 12988 * case inherit_event() will create individual events, similar to what 12989 * perf_group_detach() would do anyway. 12990 */ 12991 for_each_sibling_event(sub, parent_event) { 12992 child_ctr = inherit_event(sub, parent, parent_ctx, 12993 child, leader, child_ctx); 12994 if (IS_ERR(child_ctr)) 12995 return PTR_ERR(child_ctr); 12996 12997 if (sub->aux_event == parent_event && child_ctr && 12998 !perf_get_aux_event(child_ctr, leader)) 12999 return -EINVAL; 13000 } 13001 return 0; 13002 } 13003 13004 /* 13005 * Creates the child task context and tries to inherit the event-group. 13006 * 13007 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave 13008 * inherited_all set when we 'fail' to inherit an orphaned event; this is 13009 * consistent with perf_event_release_kernel() removing all child events. 13010 * 13011 * Returns: 13012 * - 0 on success 13013 * - <0 on error 13014 */ 13015 static int 13016 inherit_task_group(struct perf_event *event, struct task_struct *parent, 13017 struct perf_event_context *parent_ctx, 13018 struct task_struct *child, int ctxn, 13019 u64 clone_flags, int *inherited_all) 13020 { 13021 int ret; 13022 struct perf_event_context *child_ctx; 13023 13024 if (!event->attr.inherit || 13025 (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) || 13026 /* Do not inherit if sigtrap and signal handlers were cleared. */ 13027 (event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) { 13028 *inherited_all = 0; 13029 return 0; 13030 } 13031 13032 child_ctx = child->perf_event_ctxp[ctxn]; 13033 if (!child_ctx) { 13034 /* 13035 * This is executed from the parent task context, so 13036 * inherit events that have been marked for cloning. 13037 * First allocate and initialize a context for the 13038 * child. 13039 */ 13040 child_ctx = alloc_perf_context(parent_ctx->pmu, child); 13041 if (!child_ctx) 13042 return -ENOMEM; 13043 13044 child->perf_event_ctxp[ctxn] = child_ctx; 13045 } 13046 13047 ret = inherit_group(event, parent, parent_ctx, 13048 child, child_ctx); 13049 13050 if (ret) 13051 *inherited_all = 0; 13052 13053 return ret; 13054 } 13055 13056 /* 13057 * Initialize the perf_event context in task_struct 13058 */ 13059 static int perf_event_init_context(struct task_struct *child, int ctxn, 13060 u64 clone_flags) 13061 { 13062 struct perf_event_context *child_ctx, *parent_ctx; 13063 struct perf_event_context *cloned_ctx; 13064 struct perf_event *event; 13065 struct task_struct *parent = current; 13066 int inherited_all = 1; 13067 unsigned long flags; 13068 int ret = 0; 13069 13070 if (likely(!parent->perf_event_ctxp[ctxn])) 13071 return 0; 13072 13073 /* 13074 * If the parent's context is a clone, pin it so it won't get 13075 * swapped under us. 13076 */ 13077 parent_ctx = perf_pin_task_context(parent, ctxn); 13078 if (!parent_ctx) 13079 return 0; 13080 13081 /* 13082 * No need to check if parent_ctx != NULL here; since we saw 13083 * it non-NULL earlier, the only reason for it to become NULL 13084 * is if we exit, and since we're currently in the middle of 13085 * a fork we can't be exiting at the same time. 13086 */ 13087 13088 /* 13089 * Lock the parent list. No need to lock the child - not PID 13090 * hashed yet and not running, so nobody can access it. 13091 */ 13092 mutex_lock(&parent_ctx->mutex); 13093 13094 /* 13095 * We dont have to disable NMIs - we are only looking at 13096 * the list, not manipulating it: 13097 */ 13098 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) { 13099 ret = inherit_task_group(event, parent, parent_ctx, 13100 child, ctxn, clone_flags, 13101 &inherited_all); 13102 if (ret) 13103 goto out_unlock; 13104 } 13105 13106 /* 13107 * We can't hold ctx->lock when iterating the ->flexible_group list due 13108 * to allocations, but we need to prevent rotation because 13109 * rotate_ctx() will change the list from interrupt context. 13110 */ 13111 raw_spin_lock_irqsave(&parent_ctx->lock, flags); 13112 parent_ctx->rotate_disable = 1; 13113 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); 13114 13115 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) { 13116 ret = inherit_task_group(event, parent, parent_ctx, 13117 child, ctxn, clone_flags, 13118 &inherited_all); 13119 if (ret) 13120 goto out_unlock; 13121 } 13122 13123 raw_spin_lock_irqsave(&parent_ctx->lock, flags); 13124 parent_ctx->rotate_disable = 0; 13125 13126 child_ctx = child->perf_event_ctxp[ctxn]; 13127 13128 if (child_ctx && inherited_all) { 13129 /* 13130 * Mark the child context as a clone of the parent 13131 * context, or of whatever the parent is a clone of. 13132 * 13133 * Note that if the parent is a clone, the holding of 13134 * parent_ctx->lock avoids it from being uncloned. 13135 */ 13136 cloned_ctx = parent_ctx->parent_ctx; 13137 if (cloned_ctx) { 13138 child_ctx->parent_ctx = cloned_ctx; 13139 child_ctx->parent_gen = parent_ctx->parent_gen; 13140 } else { 13141 child_ctx->parent_ctx = parent_ctx; 13142 child_ctx->parent_gen = parent_ctx->generation; 13143 } 13144 get_ctx(child_ctx->parent_ctx); 13145 } 13146 13147 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); 13148 out_unlock: 13149 mutex_unlock(&parent_ctx->mutex); 13150 13151 perf_unpin_context(parent_ctx); 13152 put_ctx(parent_ctx); 13153 13154 return ret; 13155 } 13156 13157 /* 13158 * Initialize the perf_event context in task_struct 13159 */ 13160 int perf_event_init_task(struct task_struct *child, u64 clone_flags) 13161 { 13162 int ctxn, ret; 13163 13164 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp)); 13165 mutex_init(&child->perf_event_mutex); 13166 INIT_LIST_HEAD(&child->perf_event_list); 13167 13168 for_each_task_context_nr(ctxn) { 13169 ret = perf_event_init_context(child, ctxn, clone_flags); 13170 if (ret) { 13171 perf_event_free_task(child); 13172 return ret; 13173 } 13174 } 13175 13176 return 0; 13177 } 13178 13179 static void __init perf_event_init_all_cpus(void) 13180 { 13181 struct swevent_htable *swhash; 13182 int cpu; 13183 13184 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL); 13185 13186 for_each_possible_cpu(cpu) { 13187 swhash = &per_cpu(swevent_htable, cpu); 13188 mutex_init(&swhash->hlist_mutex); 13189 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu)); 13190 13191 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu)); 13192 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu)); 13193 13194 #ifdef CONFIG_CGROUP_PERF 13195 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu)); 13196 #endif 13197 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu)); 13198 } 13199 } 13200 13201 static void perf_swevent_init_cpu(unsigned int cpu) 13202 { 13203 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 13204 13205 mutex_lock(&swhash->hlist_mutex); 13206 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) { 13207 struct swevent_hlist *hlist; 13208 13209 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu)); 13210 WARN_ON(!hlist); 13211 rcu_assign_pointer(swhash->swevent_hlist, hlist); 13212 } 13213 mutex_unlock(&swhash->hlist_mutex); 13214 } 13215 13216 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE 13217 static void __perf_event_exit_context(void *__info) 13218 { 13219 struct perf_event_context *ctx = __info; 13220 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 13221 struct perf_event *event; 13222 13223 raw_spin_lock(&ctx->lock); 13224 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 13225 list_for_each_entry(event, &ctx->event_list, event_entry) 13226 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP); 13227 raw_spin_unlock(&ctx->lock); 13228 } 13229 13230 static void perf_event_exit_cpu_context(int cpu) 13231 { 13232 struct perf_cpu_context *cpuctx; 13233 struct perf_event_context *ctx; 13234 struct pmu *pmu; 13235 13236 mutex_lock(&pmus_lock); 13237 list_for_each_entry(pmu, &pmus, entry) { 13238 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 13239 ctx = &cpuctx->ctx; 13240 13241 mutex_lock(&ctx->mutex); 13242 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1); 13243 cpuctx->online = 0; 13244 mutex_unlock(&ctx->mutex); 13245 } 13246 cpumask_clear_cpu(cpu, perf_online_mask); 13247 mutex_unlock(&pmus_lock); 13248 } 13249 #else 13250 13251 static void perf_event_exit_cpu_context(int cpu) { } 13252 13253 #endif 13254 13255 int perf_event_init_cpu(unsigned int cpu) 13256 { 13257 struct perf_cpu_context *cpuctx; 13258 struct perf_event_context *ctx; 13259 struct pmu *pmu; 13260 13261 perf_swevent_init_cpu(cpu); 13262 13263 mutex_lock(&pmus_lock); 13264 cpumask_set_cpu(cpu, perf_online_mask); 13265 list_for_each_entry(pmu, &pmus, entry) { 13266 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 13267 ctx = &cpuctx->ctx; 13268 13269 mutex_lock(&ctx->mutex); 13270 cpuctx->online = 1; 13271 mutex_unlock(&ctx->mutex); 13272 } 13273 mutex_unlock(&pmus_lock); 13274 13275 return 0; 13276 } 13277 13278 int perf_event_exit_cpu(unsigned int cpu) 13279 { 13280 perf_event_exit_cpu_context(cpu); 13281 return 0; 13282 } 13283 13284 static int 13285 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v) 13286 { 13287 int cpu; 13288 13289 for_each_online_cpu(cpu) 13290 perf_event_exit_cpu(cpu); 13291 13292 return NOTIFY_OK; 13293 } 13294 13295 /* 13296 * Run the perf reboot notifier at the very last possible moment so that 13297 * the generic watchdog code runs as long as possible. 13298 */ 13299 static struct notifier_block perf_reboot_notifier = { 13300 .notifier_call = perf_reboot, 13301 .priority = INT_MIN, 13302 }; 13303 13304 void __init perf_event_init(void) 13305 { 13306 int ret; 13307 13308 idr_init(&pmu_idr); 13309 13310 perf_event_init_all_cpus(); 13311 init_srcu_struct(&pmus_srcu); 13312 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE); 13313 perf_pmu_register(&perf_cpu_clock, NULL, -1); 13314 perf_pmu_register(&perf_task_clock, NULL, -1); 13315 perf_tp_register(); 13316 perf_event_init_cpu(smp_processor_id()); 13317 register_reboot_notifier(&perf_reboot_notifier); 13318 13319 ret = init_hw_breakpoint(); 13320 WARN(ret, "hw_breakpoint initialization failed with: %d", ret); 13321 13322 perf_event_cache = KMEM_CACHE(perf_event, SLAB_PANIC); 13323 13324 /* 13325 * Build time assertion that we keep the data_head at the intended 13326 * location. IOW, validation we got the __reserved[] size right. 13327 */ 13328 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head)) 13329 != 1024); 13330 } 13331 13332 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr, 13333 char *page) 13334 { 13335 struct perf_pmu_events_attr *pmu_attr = 13336 container_of(attr, struct perf_pmu_events_attr, attr); 13337 13338 if (pmu_attr->event_str) 13339 return sprintf(page, "%s\n", pmu_attr->event_str); 13340 13341 return 0; 13342 } 13343 EXPORT_SYMBOL_GPL(perf_event_sysfs_show); 13344 13345 static int __init perf_event_sysfs_init(void) 13346 { 13347 struct pmu *pmu; 13348 int ret; 13349 13350 mutex_lock(&pmus_lock); 13351 13352 ret = bus_register(&pmu_bus); 13353 if (ret) 13354 goto unlock; 13355 13356 list_for_each_entry(pmu, &pmus, entry) { 13357 if (!pmu->name || pmu->type < 0) 13358 continue; 13359 13360 ret = pmu_dev_alloc(pmu); 13361 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret); 13362 } 13363 pmu_bus_running = 1; 13364 ret = 0; 13365 13366 unlock: 13367 mutex_unlock(&pmus_lock); 13368 13369 return ret; 13370 } 13371 device_initcall(perf_event_sysfs_init); 13372 13373 #ifdef CONFIG_CGROUP_PERF 13374 static struct cgroup_subsys_state * 13375 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) 13376 { 13377 struct perf_cgroup *jc; 13378 13379 jc = kzalloc(sizeof(*jc), GFP_KERNEL); 13380 if (!jc) 13381 return ERR_PTR(-ENOMEM); 13382 13383 jc->info = alloc_percpu(struct perf_cgroup_info); 13384 if (!jc->info) { 13385 kfree(jc); 13386 return ERR_PTR(-ENOMEM); 13387 } 13388 13389 return &jc->css; 13390 } 13391 13392 static void perf_cgroup_css_free(struct cgroup_subsys_state *css) 13393 { 13394 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css); 13395 13396 free_percpu(jc->info); 13397 kfree(jc); 13398 } 13399 13400 static int perf_cgroup_css_online(struct cgroup_subsys_state *css) 13401 { 13402 perf_event_cgroup(css->cgroup); 13403 return 0; 13404 } 13405 13406 static int __perf_cgroup_move(void *info) 13407 { 13408 struct task_struct *task = info; 13409 rcu_read_lock(); 13410 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN); 13411 rcu_read_unlock(); 13412 return 0; 13413 } 13414 13415 static void perf_cgroup_attach(struct cgroup_taskset *tset) 13416 { 13417 struct task_struct *task; 13418 struct cgroup_subsys_state *css; 13419 13420 cgroup_taskset_for_each(task, css, tset) 13421 task_function_call(task, __perf_cgroup_move, task); 13422 } 13423 13424 struct cgroup_subsys perf_event_cgrp_subsys = { 13425 .css_alloc = perf_cgroup_css_alloc, 13426 .css_free = perf_cgroup_css_free, 13427 .css_online = perf_cgroup_css_online, 13428 .attach = perf_cgroup_attach, 13429 /* 13430 * Implicitly enable on dfl hierarchy so that perf events can 13431 * always be filtered by cgroup2 path as long as perf_event 13432 * controller is not mounted on a legacy hierarchy. 13433 */ 13434 .implicit_on_dfl = true, 13435 .threaded = true, 13436 }; 13437 #endif /* CONFIG_CGROUP_PERF */ 13438