1 /* 2 * Performance events core code: 3 * 4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de> 5 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar 6 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra 7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com> 8 * 9 * For licensing details see kernel-base/COPYING 10 */ 11 12 #include <linux/fs.h> 13 #include <linux/mm.h> 14 #include <linux/cpu.h> 15 #include <linux/smp.h> 16 #include <linux/idr.h> 17 #include <linux/file.h> 18 #include <linux/poll.h> 19 #include <linux/slab.h> 20 #include <linux/hash.h> 21 #include <linux/tick.h> 22 #include <linux/sysfs.h> 23 #include <linux/dcache.h> 24 #include <linux/percpu.h> 25 #include <linux/ptrace.h> 26 #include <linux/reboot.h> 27 #include <linux/vmstat.h> 28 #include <linux/device.h> 29 #include <linux/export.h> 30 #include <linux/vmalloc.h> 31 #include <linux/hardirq.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 50 #include "internal.h" 51 52 #include <asm/irq_regs.h> 53 54 typedef int (*remote_function_f)(void *); 55 56 struct remote_function_call { 57 struct task_struct *p; 58 remote_function_f func; 59 void *info; 60 int ret; 61 }; 62 63 static void remote_function(void *data) 64 { 65 struct remote_function_call *tfc = data; 66 struct task_struct *p = tfc->p; 67 68 if (p) { 69 /* -EAGAIN */ 70 if (task_cpu(p) != smp_processor_id()) 71 return; 72 73 /* 74 * Now that we're on right CPU with IRQs disabled, we can test 75 * if we hit the right task without races. 76 */ 77 78 tfc->ret = -ESRCH; /* No such (running) process */ 79 if (p != current) 80 return; 81 } 82 83 tfc->ret = tfc->func(tfc->info); 84 } 85 86 /** 87 * task_function_call - call a function on the cpu on which a task runs 88 * @p: the task to evaluate 89 * @func: the function to be called 90 * @info: the function call argument 91 * 92 * Calls the function @func when the task is currently running. This might 93 * be on the current CPU, which just calls the function directly 94 * 95 * returns: @func return value, or 96 * -ESRCH - when the process isn't running 97 * -EAGAIN - when the process moved away 98 */ 99 static int 100 task_function_call(struct task_struct *p, remote_function_f func, void *info) 101 { 102 struct remote_function_call data = { 103 .p = p, 104 .func = func, 105 .info = info, 106 .ret = -EAGAIN, 107 }; 108 int ret; 109 110 do { 111 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1); 112 if (!ret) 113 ret = data.ret; 114 } while (ret == -EAGAIN); 115 116 return ret; 117 } 118 119 /** 120 * cpu_function_call - call a function on the cpu 121 * @func: the function to be called 122 * @info: the function call argument 123 * 124 * Calls the function @func on the remote cpu. 125 * 126 * returns: @func return value or -ENXIO when the cpu is offline 127 */ 128 static int cpu_function_call(int cpu, remote_function_f func, void *info) 129 { 130 struct remote_function_call data = { 131 .p = NULL, 132 .func = func, 133 .info = info, 134 .ret = -ENXIO, /* No such CPU */ 135 }; 136 137 smp_call_function_single(cpu, remote_function, &data, 1); 138 139 return data.ret; 140 } 141 142 static inline struct perf_cpu_context * 143 __get_cpu_context(struct perf_event_context *ctx) 144 { 145 return this_cpu_ptr(ctx->pmu->pmu_cpu_context); 146 } 147 148 static void perf_ctx_lock(struct perf_cpu_context *cpuctx, 149 struct perf_event_context *ctx) 150 { 151 raw_spin_lock(&cpuctx->ctx.lock); 152 if (ctx) 153 raw_spin_lock(&ctx->lock); 154 } 155 156 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx, 157 struct perf_event_context *ctx) 158 { 159 if (ctx) 160 raw_spin_unlock(&ctx->lock); 161 raw_spin_unlock(&cpuctx->ctx.lock); 162 } 163 164 #define TASK_TOMBSTONE ((void *)-1L) 165 166 static bool is_kernel_event(struct perf_event *event) 167 { 168 return READ_ONCE(event->owner) == TASK_TOMBSTONE; 169 } 170 171 /* 172 * On task ctx scheduling... 173 * 174 * When !ctx->nr_events a task context will not be scheduled. This means 175 * we can disable the scheduler hooks (for performance) without leaving 176 * pending task ctx state. 177 * 178 * This however results in two special cases: 179 * 180 * - removing the last event from a task ctx; this is relatively straight 181 * forward and is done in __perf_remove_from_context. 182 * 183 * - adding the first event to a task ctx; this is tricky because we cannot 184 * rely on ctx->is_active and therefore cannot use event_function_call(). 185 * See perf_install_in_context(). 186 * 187 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set. 188 */ 189 190 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *, 191 struct perf_event_context *, void *); 192 193 struct event_function_struct { 194 struct perf_event *event; 195 event_f func; 196 void *data; 197 }; 198 199 static int event_function(void *info) 200 { 201 struct event_function_struct *efs = info; 202 struct perf_event *event = efs->event; 203 struct perf_event_context *ctx = event->ctx; 204 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 205 struct perf_event_context *task_ctx = cpuctx->task_ctx; 206 int ret = 0; 207 208 WARN_ON_ONCE(!irqs_disabled()); 209 210 perf_ctx_lock(cpuctx, task_ctx); 211 /* 212 * Since we do the IPI call without holding ctx->lock things can have 213 * changed, double check we hit the task we set out to hit. 214 */ 215 if (ctx->task) { 216 if (ctx->task != current) { 217 ret = -ESRCH; 218 goto unlock; 219 } 220 221 /* 222 * We only use event_function_call() on established contexts, 223 * and event_function() is only ever called when active (or 224 * rather, we'll have bailed in task_function_call() or the 225 * above ctx->task != current test), therefore we must have 226 * ctx->is_active here. 227 */ 228 WARN_ON_ONCE(!ctx->is_active); 229 /* 230 * And since we have ctx->is_active, cpuctx->task_ctx must 231 * match. 232 */ 233 WARN_ON_ONCE(task_ctx != ctx); 234 } else { 235 WARN_ON_ONCE(&cpuctx->ctx != ctx); 236 } 237 238 efs->func(event, cpuctx, ctx, efs->data); 239 unlock: 240 perf_ctx_unlock(cpuctx, task_ctx); 241 242 return ret; 243 } 244 245 static void event_function_local(struct perf_event *event, event_f func, void *data) 246 { 247 struct event_function_struct efs = { 248 .event = event, 249 .func = func, 250 .data = data, 251 }; 252 253 int ret = event_function(&efs); 254 WARN_ON_ONCE(ret); 255 } 256 257 static void event_function_call(struct perf_event *event, event_f func, void *data) 258 { 259 struct perf_event_context *ctx = event->ctx; 260 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */ 261 struct event_function_struct efs = { 262 .event = event, 263 .func = func, 264 .data = data, 265 }; 266 267 if (!event->parent) { 268 /* 269 * If this is a !child event, we must hold ctx::mutex to 270 * stabilize the the event->ctx relation. See 271 * perf_event_ctx_lock(). 272 */ 273 lockdep_assert_held(&ctx->mutex); 274 } 275 276 if (!task) { 277 cpu_function_call(event->cpu, event_function, &efs); 278 return; 279 } 280 281 if (task == TASK_TOMBSTONE) 282 return; 283 284 again: 285 if (!task_function_call(task, event_function, &efs)) 286 return; 287 288 raw_spin_lock_irq(&ctx->lock); 289 /* 290 * Reload the task pointer, it might have been changed by 291 * a concurrent perf_event_context_sched_out(). 292 */ 293 task = ctx->task; 294 if (task == TASK_TOMBSTONE) { 295 raw_spin_unlock_irq(&ctx->lock); 296 return; 297 } 298 if (ctx->is_active) { 299 raw_spin_unlock_irq(&ctx->lock); 300 goto again; 301 } 302 func(event, NULL, ctx, data); 303 raw_spin_unlock_irq(&ctx->lock); 304 } 305 306 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\ 307 PERF_FLAG_FD_OUTPUT |\ 308 PERF_FLAG_PID_CGROUP |\ 309 PERF_FLAG_FD_CLOEXEC) 310 311 /* 312 * branch priv levels that need permission checks 313 */ 314 #define PERF_SAMPLE_BRANCH_PERM_PLM \ 315 (PERF_SAMPLE_BRANCH_KERNEL |\ 316 PERF_SAMPLE_BRANCH_HV) 317 318 enum event_type_t { 319 EVENT_FLEXIBLE = 0x1, 320 EVENT_PINNED = 0x2, 321 EVENT_TIME = 0x4, 322 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED, 323 }; 324 325 /* 326 * perf_sched_events : >0 events exist 327 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu 328 */ 329 330 static void perf_sched_delayed(struct work_struct *work); 331 DEFINE_STATIC_KEY_FALSE(perf_sched_events); 332 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed); 333 static DEFINE_MUTEX(perf_sched_mutex); 334 static atomic_t perf_sched_count; 335 336 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events); 337 static DEFINE_PER_CPU(int, perf_sched_cb_usages); 338 339 static atomic_t nr_mmap_events __read_mostly; 340 static atomic_t nr_comm_events __read_mostly; 341 static atomic_t nr_task_events __read_mostly; 342 static atomic_t nr_freq_events __read_mostly; 343 static atomic_t nr_switch_events __read_mostly; 344 345 static LIST_HEAD(pmus); 346 static DEFINE_MUTEX(pmus_lock); 347 static struct srcu_struct pmus_srcu; 348 349 /* 350 * perf event paranoia level: 351 * -1 - not paranoid at all 352 * 0 - disallow raw tracepoint access for unpriv 353 * 1 - disallow cpu events for unpriv 354 * 2 - disallow kernel profiling for unpriv 355 */ 356 int sysctl_perf_event_paranoid __read_mostly = 2; 357 358 /* Minimum for 512 kiB + 1 user control page */ 359 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */ 360 361 /* 362 * max perf event sample rate 363 */ 364 #define DEFAULT_MAX_SAMPLE_RATE 100000 365 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE) 366 #define DEFAULT_CPU_TIME_MAX_PERCENT 25 367 368 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE; 369 370 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ); 371 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS; 372 373 static int perf_sample_allowed_ns __read_mostly = 374 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100; 375 376 static void update_perf_cpu_limits(void) 377 { 378 u64 tmp = perf_sample_period_ns; 379 380 tmp *= sysctl_perf_cpu_time_max_percent; 381 tmp = div_u64(tmp, 100); 382 if (!tmp) 383 tmp = 1; 384 385 WRITE_ONCE(perf_sample_allowed_ns, tmp); 386 } 387 388 static int perf_rotate_context(struct perf_cpu_context *cpuctx); 389 390 int perf_proc_update_handler(struct ctl_table *table, int write, 391 void __user *buffer, size_t *lenp, 392 loff_t *ppos) 393 { 394 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); 395 396 if (ret || !write) 397 return ret; 398 399 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ); 400 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; 401 update_perf_cpu_limits(); 402 403 return 0; 404 } 405 406 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT; 407 408 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write, 409 void __user *buffer, size_t *lenp, 410 loff_t *ppos) 411 { 412 int ret = proc_dointvec(table, write, buffer, lenp, ppos); 413 414 if (ret || !write) 415 return ret; 416 417 if (sysctl_perf_cpu_time_max_percent == 100 || 418 sysctl_perf_cpu_time_max_percent == 0) { 419 printk(KERN_WARNING 420 "perf: Dynamic interrupt throttling disabled, can hang your system!\n"); 421 WRITE_ONCE(perf_sample_allowed_ns, 0); 422 } else { 423 update_perf_cpu_limits(); 424 } 425 426 return 0; 427 } 428 429 /* 430 * perf samples are done in some very critical code paths (NMIs). 431 * If they take too much CPU time, the system can lock up and not 432 * get any real work done. This will drop the sample rate when 433 * we detect that events are taking too long. 434 */ 435 #define NR_ACCUMULATED_SAMPLES 128 436 static DEFINE_PER_CPU(u64, running_sample_length); 437 438 static u64 __report_avg; 439 static u64 __report_allowed; 440 441 static void perf_duration_warn(struct irq_work *w) 442 { 443 printk_ratelimited(KERN_WARNING 444 "perf: interrupt took too long (%lld > %lld), lowering " 445 "kernel.perf_event_max_sample_rate to %d\n", 446 __report_avg, __report_allowed, 447 sysctl_perf_event_sample_rate); 448 } 449 450 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn); 451 452 void perf_sample_event_took(u64 sample_len_ns) 453 { 454 u64 max_len = READ_ONCE(perf_sample_allowed_ns); 455 u64 running_len; 456 u64 avg_len; 457 u32 max; 458 459 if (max_len == 0) 460 return; 461 462 /* Decay the counter by 1 average sample. */ 463 running_len = __this_cpu_read(running_sample_length); 464 running_len -= running_len/NR_ACCUMULATED_SAMPLES; 465 running_len += sample_len_ns; 466 __this_cpu_write(running_sample_length, running_len); 467 468 /* 469 * Note: this will be biased artifically low until we have 470 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us 471 * from having to maintain a count. 472 */ 473 avg_len = running_len/NR_ACCUMULATED_SAMPLES; 474 if (avg_len <= max_len) 475 return; 476 477 __report_avg = avg_len; 478 __report_allowed = max_len; 479 480 /* 481 * Compute a throttle threshold 25% below the current duration. 482 */ 483 avg_len += avg_len / 4; 484 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent; 485 if (avg_len < max) 486 max /= (u32)avg_len; 487 else 488 max = 1; 489 490 WRITE_ONCE(perf_sample_allowed_ns, avg_len); 491 WRITE_ONCE(max_samples_per_tick, max); 492 493 sysctl_perf_event_sample_rate = max * HZ; 494 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; 495 496 if (!irq_work_queue(&perf_duration_work)) { 497 early_printk("perf: interrupt took too long (%lld > %lld), lowering " 498 "kernel.perf_event_max_sample_rate to %d\n", 499 __report_avg, __report_allowed, 500 sysctl_perf_event_sample_rate); 501 } 502 } 503 504 static atomic64_t perf_event_id; 505 506 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, 507 enum event_type_t event_type); 508 509 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, 510 enum event_type_t event_type, 511 struct task_struct *task); 512 513 static void update_context_time(struct perf_event_context *ctx); 514 static u64 perf_event_time(struct perf_event *event); 515 516 void __weak perf_event_print_debug(void) { } 517 518 extern __weak const char *perf_pmu_name(void) 519 { 520 return "pmu"; 521 } 522 523 static inline u64 perf_clock(void) 524 { 525 return local_clock(); 526 } 527 528 static inline u64 perf_event_clock(struct perf_event *event) 529 { 530 return event->clock(); 531 } 532 533 #ifdef CONFIG_CGROUP_PERF 534 535 static inline bool 536 perf_cgroup_match(struct perf_event *event) 537 { 538 struct perf_event_context *ctx = event->ctx; 539 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 540 541 /* @event doesn't care about cgroup */ 542 if (!event->cgrp) 543 return true; 544 545 /* wants specific cgroup scope but @cpuctx isn't associated with any */ 546 if (!cpuctx->cgrp) 547 return false; 548 549 /* 550 * Cgroup scoping is recursive. An event enabled for a cgroup is 551 * also enabled for all its descendant cgroups. If @cpuctx's 552 * cgroup is a descendant of @event's (the test covers identity 553 * case), it's a match. 554 */ 555 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup, 556 event->cgrp->css.cgroup); 557 } 558 559 static inline void perf_detach_cgroup(struct perf_event *event) 560 { 561 css_put(&event->cgrp->css); 562 event->cgrp = NULL; 563 } 564 565 static inline int is_cgroup_event(struct perf_event *event) 566 { 567 return event->cgrp != NULL; 568 } 569 570 static inline u64 perf_cgroup_event_time(struct perf_event *event) 571 { 572 struct perf_cgroup_info *t; 573 574 t = per_cpu_ptr(event->cgrp->info, event->cpu); 575 return t->time; 576 } 577 578 static inline void __update_cgrp_time(struct perf_cgroup *cgrp) 579 { 580 struct perf_cgroup_info *info; 581 u64 now; 582 583 now = perf_clock(); 584 585 info = this_cpu_ptr(cgrp->info); 586 587 info->time += now - info->timestamp; 588 info->timestamp = now; 589 } 590 591 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) 592 { 593 struct perf_cgroup *cgrp_out = cpuctx->cgrp; 594 if (cgrp_out) 595 __update_cgrp_time(cgrp_out); 596 } 597 598 static inline void update_cgrp_time_from_event(struct perf_event *event) 599 { 600 struct perf_cgroup *cgrp; 601 602 /* 603 * ensure we access cgroup data only when needed and 604 * when we know the cgroup is pinned (css_get) 605 */ 606 if (!is_cgroup_event(event)) 607 return; 608 609 cgrp = perf_cgroup_from_task(current, event->ctx); 610 /* 611 * Do not update time when cgroup is not active 612 */ 613 if (cgrp == event->cgrp) 614 __update_cgrp_time(event->cgrp); 615 } 616 617 static inline void 618 perf_cgroup_set_timestamp(struct task_struct *task, 619 struct perf_event_context *ctx) 620 { 621 struct perf_cgroup *cgrp; 622 struct perf_cgroup_info *info; 623 624 /* 625 * ctx->lock held by caller 626 * ensure we do not access cgroup data 627 * unless we have the cgroup pinned (css_get) 628 */ 629 if (!task || !ctx->nr_cgroups) 630 return; 631 632 cgrp = perf_cgroup_from_task(task, ctx); 633 info = this_cpu_ptr(cgrp->info); 634 info->timestamp = ctx->timestamp; 635 } 636 637 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */ 638 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */ 639 640 /* 641 * reschedule events based on the cgroup constraint of task. 642 * 643 * mode SWOUT : schedule out everything 644 * mode SWIN : schedule in based on cgroup for next 645 */ 646 static void perf_cgroup_switch(struct task_struct *task, int mode) 647 { 648 struct perf_cpu_context *cpuctx; 649 struct pmu *pmu; 650 unsigned long flags; 651 652 /* 653 * disable interrupts to avoid geting nr_cgroup 654 * changes via __perf_event_disable(). Also 655 * avoids preemption. 656 */ 657 local_irq_save(flags); 658 659 /* 660 * we reschedule only in the presence of cgroup 661 * constrained events. 662 */ 663 664 list_for_each_entry_rcu(pmu, &pmus, entry) { 665 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 666 if (cpuctx->unique_pmu != pmu) 667 continue; /* ensure we process each cpuctx once */ 668 669 /* 670 * perf_cgroup_events says at least one 671 * context on this CPU has cgroup events. 672 * 673 * ctx->nr_cgroups reports the number of cgroup 674 * events for a context. 675 */ 676 if (cpuctx->ctx.nr_cgroups > 0) { 677 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 678 perf_pmu_disable(cpuctx->ctx.pmu); 679 680 if (mode & PERF_CGROUP_SWOUT) { 681 cpu_ctx_sched_out(cpuctx, EVENT_ALL); 682 /* 683 * must not be done before ctxswout due 684 * to event_filter_match() in event_sched_out() 685 */ 686 cpuctx->cgrp = NULL; 687 } 688 689 if (mode & PERF_CGROUP_SWIN) { 690 WARN_ON_ONCE(cpuctx->cgrp); 691 /* 692 * set cgrp before ctxsw in to allow 693 * event_filter_match() to not have to pass 694 * task around 695 * we pass the cpuctx->ctx to perf_cgroup_from_task() 696 * because cgorup events are only per-cpu 697 */ 698 cpuctx->cgrp = perf_cgroup_from_task(task, &cpuctx->ctx); 699 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task); 700 } 701 perf_pmu_enable(cpuctx->ctx.pmu); 702 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 703 } 704 } 705 706 local_irq_restore(flags); 707 } 708 709 static inline void perf_cgroup_sched_out(struct task_struct *task, 710 struct task_struct *next) 711 { 712 struct perf_cgroup *cgrp1; 713 struct perf_cgroup *cgrp2 = NULL; 714 715 rcu_read_lock(); 716 /* 717 * we come here when we know perf_cgroup_events > 0 718 * we do not need to pass the ctx here because we know 719 * we are holding the rcu lock 720 */ 721 cgrp1 = perf_cgroup_from_task(task, NULL); 722 cgrp2 = perf_cgroup_from_task(next, NULL); 723 724 /* 725 * only schedule out current cgroup events if we know 726 * that we are switching to a different cgroup. Otherwise, 727 * do no touch the cgroup events. 728 */ 729 if (cgrp1 != cgrp2) 730 perf_cgroup_switch(task, PERF_CGROUP_SWOUT); 731 732 rcu_read_unlock(); 733 } 734 735 static inline void perf_cgroup_sched_in(struct task_struct *prev, 736 struct task_struct *task) 737 { 738 struct perf_cgroup *cgrp1; 739 struct perf_cgroup *cgrp2 = NULL; 740 741 rcu_read_lock(); 742 /* 743 * we come here when we know perf_cgroup_events > 0 744 * we do not need to pass the ctx here because we know 745 * we are holding the rcu lock 746 */ 747 cgrp1 = perf_cgroup_from_task(task, NULL); 748 cgrp2 = perf_cgroup_from_task(prev, NULL); 749 750 /* 751 * only need to schedule in cgroup events if we are changing 752 * cgroup during ctxsw. Cgroup events were not scheduled 753 * out of ctxsw out if that was not the case. 754 */ 755 if (cgrp1 != cgrp2) 756 perf_cgroup_switch(task, PERF_CGROUP_SWIN); 757 758 rcu_read_unlock(); 759 } 760 761 static inline int perf_cgroup_connect(int fd, struct perf_event *event, 762 struct perf_event_attr *attr, 763 struct perf_event *group_leader) 764 { 765 struct perf_cgroup *cgrp; 766 struct cgroup_subsys_state *css; 767 struct fd f = fdget(fd); 768 int ret = 0; 769 770 if (!f.file) 771 return -EBADF; 772 773 css = css_tryget_online_from_dir(f.file->f_path.dentry, 774 &perf_event_cgrp_subsys); 775 if (IS_ERR(css)) { 776 ret = PTR_ERR(css); 777 goto out; 778 } 779 780 cgrp = container_of(css, struct perf_cgroup, css); 781 event->cgrp = cgrp; 782 783 /* 784 * all events in a group must monitor 785 * the same cgroup because a task belongs 786 * to only one perf cgroup at a time 787 */ 788 if (group_leader && group_leader->cgrp != cgrp) { 789 perf_detach_cgroup(event); 790 ret = -EINVAL; 791 } 792 out: 793 fdput(f); 794 return ret; 795 } 796 797 static inline void 798 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) 799 { 800 struct perf_cgroup_info *t; 801 t = per_cpu_ptr(event->cgrp->info, event->cpu); 802 event->shadow_ctx_time = now - t->timestamp; 803 } 804 805 static inline void 806 perf_cgroup_defer_enabled(struct perf_event *event) 807 { 808 /* 809 * when the current task's perf cgroup does not match 810 * the event's, we need to remember to call the 811 * perf_mark_enable() function the first time a task with 812 * a matching perf cgroup is scheduled in. 813 */ 814 if (is_cgroup_event(event) && !perf_cgroup_match(event)) 815 event->cgrp_defer_enabled = 1; 816 } 817 818 static inline void 819 perf_cgroup_mark_enabled(struct perf_event *event, 820 struct perf_event_context *ctx) 821 { 822 struct perf_event *sub; 823 u64 tstamp = perf_event_time(event); 824 825 if (!event->cgrp_defer_enabled) 826 return; 827 828 event->cgrp_defer_enabled = 0; 829 830 event->tstamp_enabled = tstamp - event->total_time_enabled; 831 list_for_each_entry(sub, &event->sibling_list, group_entry) { 832 if (sub->state >= PERF_EVENT_STATE_INACTIVE) { 833 sub->tstamp_enabled = tstamp - sub->total_time_enabled; 834 sub->cgrp_defer_enabled = 0; 835 } 836 } 837 } 838 #else /* !CONFIG_CGROUP_PERF */ 839 840 static inline bool 841 perf_cgroup_match(struct perf_event *event) 842 { 843 return true; 844 } 845 846 static inline void perf_detach_cgroup(struct perf_event *event) 847 {} 848 849 static inline int is_cgroup_event(struct perf_event *event) 850 { 851 return 0; 852 } 853 854 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event) 855 { 856 return 0; 857 } 858 859 static inline void update_cgrp_time_from_event(struct perf_event *event) 860 { 861 } 862 863 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) 864 { 865 } 866 867 static inline void perf_cgroup_sched_out(struct task_struct *task, 868 struct task_struct *next) 869 { 870 } 871 872 static inline void perf_cgroup_sched_in(struct task_struct *prev, 873 struct task_struct *task) 874 { 875 } 876 877 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event, 878 struct perf_event_attr *attr, 879 struct perf_event *group_leader) 880 { 881 return -EINVAL; 882 } 883 884 static inline void 885 perf_cgroup_set_timestamp(struct task_struct *task, 886 struct perf_event_context *ctx) 887 { 888 } 889 890 void 891 perf_cgroup_switch(struct task_struct *task, struct task_struct *next) 892 { 893 } 894 895 static inline void 896 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) 897 { 898 } 899 900 static inline u64 perf_cgroup_event_time(struct perf_event *event) 901 { 902 return 0; 903 } 904 905 static inline void 906 perf_cgroup_defer_enabled(struct perf_event *event) 907 { 908 } 909 910 static inline void 911 perf_cgroup_mark_enabled(struct perf_event *event, 912 struct perf_event_context *ctx) 913 { 914 } 915 #endif 916 917 /* 918 * set default to be dependent on timer tick just 919 * like original code 920 */ 921 #define PERF_CPU_HRTIMER (1000 / HZ) 922 /* 923 * function must be called with interrupts disbled 924 */ 925 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr) 926 { 927 struct perf_cpu_context *cpuctx; 928 int rotations = 0; 929 930 WARN_ON(!irqs_disabled()); 931 932 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer); 933 rotations = perf_rotate_context(cpuctx); 934 935 raw_spin_lock(&cpuctx->hrtimer_lock); 936 if (rotations) 937 hrtimer_forward_now(hr, cpuctx->hrtimer_interval); 938 else 939 cpuctx->hrtimer_active = 0; 940 raw_spin_unlock(&cpuctx->hrtimer_lock); 941 942 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART; 943 } 944 945 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu) 946 { 947 struct hrtimer *timer = &cpuctx->hrtimer; 948 struct pmu *pmu = cpuctx->ctx.pmu; 949 u64 interval; 950 951 /* no multiplexing needed for SW PMU */ 952 if (pmu->task_ctx_nr == perf_sw_context) 953 return; 954 955 /* 956 * check default is sane, if not set then force to 957 * default interval (1/tick) 958 */ 959 interval = pmu->hrtimer_interval_ms; 960 if (interval < 1) 961 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER; 962 963 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval); 964 965 raw_spin_lock_init(&cpuctx->hrtimer_lock); 966 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED); 967 timer->function = perf_mux_hrtimer_handler; 968 } 969 970 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx) 971 { 972 struct hrtimer *timer = &cpuctx->hrtimer; 973 struct pmu *pmu = cpuctx->ctx.pmu; 974 unsigned long flags; 975 976 /* not for SW PMU */ 977 if (pmu->task_ctx_nr == perf_sw_context) 978 return 0; 979 980 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags); 981 if (!cpuctx->hrtimer_active) { 982 cpuctx->hrtimer_active = 1; 983 hrtimer_forward_now(timer, cpuctx->hrtimer_interval); 984 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED); 985 } 986 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags); 987 988 return 0; 989 } 990 991 void perf_pmu_disable(struct pmu *pmu) 992 { 993 int *count = this_cpu_ptr(pmu->pmu_disable_count); 994 if (!(*count)++) 995 pmu->pmu_disable(pmu); 996 } 997 998 void perf_pmu_enable(struct pmu *pmu) 999 { 1000 int *count = this_cpu_ptr(pmu->pmu_disable_count); 1001 if (!--(*count)) 1002 pmu->pmu_enable(pmu); 1003 } 1004 1005 static DEFINE_PER_CPU(struct list_head, active_ctx_list); 1006 1007 /* 1008 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and 1009 * perf_event_task_tick() are fully serialized because they're strictly cpu 1010 * affine and perf_event_ctx{activate,deactivate} are called with IRQs 1011 * disabled, while perf_event_task_tick is called from IRQ context. 1012 */ 1013 static void perf_event_ctx_activate(struct perf_event_context *ctx) 1014 { 1015 struct list_head *head = this_cpu_ptr(&active_ctx_list); 1016 1017 WARN_ON(!irqs_disabled()); 1018 1019 WARN_ON(!list_empty(&ctx->active_ctx_list)); 1020 1021 list_add(&ctx->active_ctx_list, head); 1022 } 1023 1024 static void perf_event_ctx_deactivate(struct perf_event_context *ctx) 1025 { 1026 WARN_ON(!irqs_disabled()); 1027 1028 WARN_ON(list_empty(&ctx->active_ctx_list)); 1029 1030 list_del_init(&ctx->active_ctx_list); 1031 } 1032 1033 static void get_ctx(struct perf_event_context *ctx) 1034 { 1035 WARN_ON(!atomic_inc_not_zero(&ctx->refcount)); 1036 } 1037 1038 static void free_ctx(struct rcu_head *head) 1039 { 1040 struct perf_event_context *ctx; 1041 1042 ctx = container_of(head, struct perf_event_context, rcu_head); 1043 kfree(ctx->task_ctx_data); 1044 kfree(ctx); 1045 } 1046 1047 static void put_ctx(struct perf_event_context *ctx) 1048 { 1049 if (atomic_dec_and_test(&ctx->refcount)) { 1050 if (ctx->parent_ctx) 1051 put_ctx(ctx->parent_ctx); 1052 if (ctx->task && ctx->task != TASK_TOMBSTONE) 1053 put_task_struct(ctx->task); 1054 call_rcu(&ctx->rcu_head, free_ctx); 1055 } 1056 } 1057 1058 /* 1059 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and 1060 * perf_pmu_migrate_context() we need some magic. 1061 * 1062 * Those places that change perf_event::ctx will hold both 1063 * perf_event_ctx::mutex of the 'old' and 'new' ctx value. 1064 * 1065 * Lock ordering is by mutex address. There are two other sites where 1066 * perf_event_context::mutex nests and those are: 1067 * 1068 * - perf_event_exit_task_context() [ child , 0 ] 1069 * perf_event_exit_event() 1070 * put_event() [ parent, 1 ] 1071 * 1072 * - perf_event_init_context() [ parent, 0 ] 1073 * inherit_task_group() 1074 * inherit_group() 1075 * inherit_event() 1076 * perf_event_alloc() 1077 * perf_init_event() 1078 * perf_try_init_event() [ child , 1 ] 1079 * 1080 * While it appears there is an obvious deadlock here -- the parent and child 1081 * nesting levels are inverted between the two. This is in fact safe because 1082 * life-time rules separate them. That is an exiting task cannot fork, and a 1083 * spawning task cannot (yet) exit. 1084 * 1085 * But remember that that these are parent<->child context relations, and 1086 * migration does not affect children, therefore these two orderings should not 1087 * interact. 1088 * 1089 * The change in perf_event::ctx does not affect children (as claimed above) 1090 * because the sys_perf_event_open() case will install a new event and break 1091 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only 1092 * concerned with cpuctx and that doesn't have children. 1093 * 1094 * The places that change perf_event::ctx will issue: 1095 * 1096 * perf_remove_from_context(); 1097 * synchronize_rcu(); 1098 * perf_install_in_context(); 1099 * 1100 * to affect the change. The remove_from_context() + synchronize_rcu() should 1101 * quiesce the event, after which we can install it in the new location. This 1102 * means that only external vectors (perf_fops, prctl) can perturb the event 1103 * while in transit. Therefore all such accessors should also acquire 1104 * perf_event_context::mutex to serialize against this. 1105 * 1106 * However; because event->ctx can change while we're waiting to acquire 1107 * ctx->mutex we must be careful and use the below perf_event_ctx_lock() 1108 * function. 1109 * 1110 * Lock order: 1111 * cred_guard_mutex 1112 * task_struct::perf_event_mutex 1113 * perf_event_context::mutex 1114 * perf_event::child_mutex; 1115 * perf_event_context::lock 1116 * perf_event::mmap_mutex 1117 * mmap_sem 1118 */ 1119 static struct perf_event_context * 1120 perf_event_ctx_lock_nested(struct perf_event *event, int nesting) 1121 { 1122 struct perf_event_context *ctx; 1123 1124 again: 1125 rcu_read_lock(); 1126 ctx = ACCESS_ONCE(event->ctx); 1127 if (!atomic_inc_not_zero(&ctx->refcount)) { 1128 rcu_read_unlock(); 1129 goto again; 1130 } 1131 rcu_read_unlock(); 1132 1133 mutex_lock_nested(&ctx->mutex, nesting); 1134 if (event->ctx != ctx) { 1135 mutex_unlock(&ctx->mutex); 1136 put_ctx(ctx); 1137 goto again; 1138 } 1139 1140 return ctx; 1141 } 1142 1143 static inline struct perf_event_context * 1144 perf_event_ctx_lock(struct perf_event *event) 1145 { 1146 return perf_event_ctx_lock_nested(event, 0); 1147 } 1148 1149 static void perf_event_ctx_unlock(struct perf_event *event, 1150 struct perf_event_context *ctx) 1151 { 1152 mutex_unlock(&ctx->mutex); 1153 put_ctx(ctx); 1154 } 1155 1156 /* 1157 * This must be done under the ctx->lock, such as to serialize against 1158 * context_equiv(), therefore we cannot call put_ctx() since that might end up 1159 * calling scheduler related locks and ctx->lock nests inside those. 1160 */ 1161 static __must_check struct perf_event_context * 1162 unclone_ctx(struct perf_event_context *ctx) 1163 { 1164 struct perf_event_context *parent_ctx = ctx->parent_ctx; 1165 1166 lockdep_assert_held(&ctx->lock); 1167 1168 if (parent_ctx) 1169 ctx->parent_ctx = NULL; 1170 ctx->generation++; 1171 1172 return parent_ctx; 1173 } 1174 1175 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) 1176 { 1177 /* 1178 * only top level events have the pid namespace they were created in 1179 */ 1180 if (event->parent) 1181 event = event->parent; 1182 1183 return task_tgid_nr_ns(p, event->ns); 1184 } 1185 1186 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) 1187 { 1188 /* 1189 * only top level events have the pid namespace they were created in 1190 */ 1191 if (event->parent) 1192 event = event->parent; 1193 1194 return task_pid_nr_ns(p, event->ns); 1195 } 1196 1197 /* 1198 * If we inherit events we want to return the parent event id 1199 * to userspace. 1200 */ 1201 static u64 primary_event_id(struct perf_event *event) 1202 { 1203 u64 id = event->id; 1204 1205 if (event->parent) 1206 id = event->parent->id; 1207 1208 return id; 1209 } 1210 1211 /* 1212 * Get the perf_event_context for a task and lock it. 1213 * 1214 * This has to cope with with the fact that until it is locked, 1215 * the context could get moved to another task. 1216 */ 1217 static struct perf_event_context * 1218 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags) 1219 { 1220 struct perf_event_context *ctx; 1221 1222 retry: 1223 /* 1224 * One of the few rules of preemptible RCU is that one cannot do 1225 * rcu_read_unlock() while holding a scheduler (or nested) lock when 1226 * part of the read side critical section was irqs-enabled -- see 1227 * rcu_read_unlock_special(). 1228 * 1229 * Since ctx->lock nests under rq->lock we must ensure the entire read 1230 * side critical section has interrupts disabled. 1231 */ 1232 local_irq_save(*flags); 1233 rcu_read_lock(); 1234 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]); 1235 if (ctx) { 1236 /* 1237 * If this context is a clone of another, it might 1238 * get swapped for another underneath us by 1239 * perf_event_task_sched_out, though the 1240 * rcu_read_lock() protects us from any context 1241 * getting freed. Lock the context and check if it 1242 * got swapped before we could get the lock, and retry 1243 * if so. If we locked the right context, then it 1244 * can't get swapped on us any more. 1245 */ 1246 raw_spin_lock(&ctx->lock); 1247 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) { 1248 raw_spin_unlock(&ctx->lock); 1249 rcu_read_unlock(); 1250 local_irq_restore(*flags); 1251 goto retry; 1252 } 1253 1254 if (ctx->task == TASK_TOMBSTONE || 1255 !atomic_inc_not_zero(&ctx->refcount)) { 1256 raw_spin_unlock(&ctx->lock); 1257 ctx = NULL; 1258 } else { 1259 WARN_ON_ONCE(ctx->task != task); 1260 } 1261 } 1262 rcu_read_unlock(); 1263 if (!ctx) 1264 local_irq_restore(*flags); 1265 return ctx; 1266 } 1267 1268 /* 1269 * Get the context for a task and increment its pin_count so it 1270 * can't get swapped to another task. This also increments its 1271 * reference count so that the context can't get freed. 1272 */ 1273 static struct perf_event_context * 1274 perf_pin_task_context(struct task_struct *task, int ctxn) 1275 { 1276 struct perf_event_context *ctx; 1277 unsigned long flags; 1278 1279 ctx = perf_lock_task_context(task, ctxn, &flags); 1280 if (ctx) { 1281 ++ctx->pin_count; 1282 raw_spin_unlock_irqrestore(&ctx->lock, flags); 1283 } 1284 return ctx; 1285 } 1286 1287 static void perf_unpin_context(struct perf_event_context *ctx) 1288 { 1289 unsigned long flags; 1290 1291 raw_spin_lock_irqsave(&ctx->lock, flags); 1292 --ctx->pin_count; 1293 raw_spin_unlock_irqrestore(&ctx->lock, flags); 1294 } 1295 1296 /* 1297 * Update the record of the current time in a context. 1298 */ 1299 static void update_context_time(struct perf_event_context *ctx) 1300 { 1301 u64 now = perf_clock(); 1302 1303 ctx->time += now - ctx->timestamp; 1304 ctx->timestamp = now; 1305 } 1306 1307 static u64 perf_event_time(struct perf_event *event) 1308 { 1309 struct perf_event_context *ctx = event->ctx; 1310 1311 if (is_cgroup_event(event)) 1312 return perf_cgroup_event_time(event); 1313 1314 return ctx ? ctx->time : 0; 1315 } 1316 1317 /* 1318 * Update the total_time_enabled and total_time_running fields for a event. 1319 */ 1320 static void update_event_times(struct perf_event *event) 1321 { 1322 struct perf_event_context *ctx = event->ctx; 1323 u64 run_end; 1324 1325 lockdep_assert_held(&ctx->lock); 1326 1327 if (event->state < PERF_EVENT_STATE_INACTIVE || 1328 event->group_leader->state < PERF_EVENT_STATE_INACTIVE) 1329 return; 1330 1331 /* 1332 * in cgroup mode, time_enabled represents 1333 * the time the event was enabled AND active 1334 * tasks were in the monitored cgroup. This is 1335 * independent of the activity of the context as 1336 * there may be a mix of cgroup and non-cgroup events. 1337 * 1338 * That is why we treat cgroup events differently 1339 * here. 1340 */ 1341 if (is_cgroup_event(event)) 1342 run_end = perf_cgroup_event_time(event); 1343 else if (ctx->is_active) 1344 run_end = ctx->time; 1345 else 1346 run_end = event->tstamp_stopped; 1347 1348 event->total_time_enabled = run_end - event->tstamp_enabled; 1349 1350 if (event->state == PERF_EVENT_STATE_INACTIVE) 1351 run_end = event->tstamp_stopped; 1352 else 1353 run_end = perf_event_time(event); 1354 1355 event->total_time_running = run_end - event->tstamp_running; 1356 1357 } 1358 1359 /* 1360 * Update total_time_enabled and total_time_running for all events in a group. 1361 */ 1362 static void update_group_times(struct perf_event *leader) 1363 { 1364 struct perf_event *event; 1365 1366 update_event_times(leader); 1367 list_for_each_entry(event, &leader->sibling_list, group_entry) 1368 update_event_times(event); 1369 } 1370 1371 static struct list_head * 1372 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx) 1373 { 1374 if (event->attr.pinned) 1375 return &ctx->pinned_groups; 1376 else 1377 return &ctx->flexible_groups; 1378 } 1379 1380 /* 1381 * Add a event from the lists for its context. 1382 * Must be called with ctx->mutex and ctx->lock held. 1383 */ 1384 static void 1385 list_add_event(struct perf_event *event, struct perf_event_context *ctx) 1386 { 1387 lockdep_assert_held(&ctx->lock); 1388 1389 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); 1390 event->attach_state |= PERF_ATTACH_CONTEXT; 1391 1392 /* 1393 * If we're a stand alone event or group leader, we go to the context 1394 * list, group events are kept attached to the group so that 1395 * perf_group_detach can, at all times, locate all siblings. 1396 */ 1397 if (event->group_leader == event) { 1398 struct list_head *list; 1399 1400 if (is_software_event(event)) 1401 event->group_flags |= PERF_GROUP_SOFTWARE; 1402 1403 list = ctx_group_list(event, ctx); 1404 list_add_tail(&event->group_entry, list); 1405 } 1406 1407 if (is_cgroup_event(event)) 1408 ctx->nr_cgroups++; 1409 1410 list_add_rcu(&event->event_entry, &ctx->event_list); 1411 ctx->nr_events++; 1412 if (event->attr.inherit_stat) 1413 ctx->nr_stat++; 1414 1415 ctx->generation++; 1416 } 1417 1418 /* 1419 * Initialize event state based on the perf_event_attr::disabled. 1420 */ 1421 static inline void perf_event__state_init(struct perf_event *event) 1422 { 1423 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF : 1424 PERF_EVENT_STATE_INACTIVE; 1425 } 1426 1427 static void __perf_event_read_size(struct perf_event *event, int nr_siblings) 1428 { 1429 int entry = sizeof(u64); /* value */ 1430 int size = 0; 1431 int nr = 1; 1432 1433 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 1434 size += sizeof(u64); 1435 1436 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 1437 size += sizeof(u64); 1438 1439 if (event->attr.read_format & PERF_FORMAT_ID) 1440 entry += sizeof(u64); 1441 1442 if (event->attr.read_format & PERF_FORMAT_GROUP) { 1443 nr += nr_siblings; 1444 size += sizeof(u64); 1445 } 1446 1447 size += entry * nr; 1448 event->read_size = size; 1449 } 1450 1451 static void __perf_event_header_size(struct perf_event *event, u64 sample_type) 1452 { 1453 struct perf_sample_data *data; 1454 u16 size = 0; 1455 1456 if (sample_type & PERF_SAMPLE_IP) 1457 size += sizeof(data->ip); 1458 1459 if (sample_type & PERF_SAMPLE_ADDR) 1460 size += sizeof(data->addr); 1461 1462 if (sample_type & PERF_SAMPLE_PERIOD) 1463 size += sizeof(data->period); 1464 1465 if (sample_type & PERF_SAMPLE_WEIGHT) 1466 size += sizeof(data->weight); 1467 1468 if (sample_type & PERF_SAMPLE_READ) 1469 size += event->read_size; 1470 1471 if (sample_type & PERF_SAMPLE_DATA_SRC) 1472 size += sizeof(data->data_src.val); 1473 1474 if (sample_type & PERF_SAMPLE_TRANSACTION) 1475 size += sizeof(data->txn); 1476 1477 event->header_size = size; 1478 } 1479 1480 /* 1481 * Called at perf_event creation and when events are attached/detached from a 1482 * group. 1483 */ 1484 static void perf_event__header_size(struct perf_event *event) 1485 { 1486 __perf_event_read_size(event, 1487 event->group_leader->nr_siblings); 1488 __perf_event_header_size(event, event->attr.sample_type); 1489 } 1490 1491 static void perf_event__id_header_size(struct perf_event *event) 1492 { 1493 struct perf_sample_data *data; 1494 u64 sample_type = event->attr.sample_type; 1495 u16 size = 0; 1496 1497 if (sample_type & PERF_SAMPLE_TID) 1498 size += sizeof(data->tid_entry); 1499 1500 if (sample_type & PERF_SAMPLE_TIME) 1501 size += sizeof(data->time); 1502 1503 if (sample_type & PERF_SAMPLE_IDENTIFIER) 1504 size += sizeof(data->id); 1505 1506 if (sample_type & PERF_SAMPLE_ID) 1507 size += sizeof(data->id); 1508 1509 if (sample_type & PERF_SAMPLE_STREAM_ID) 1510 size += sizeof(data->stream_id); 1511 1512 if (sample_type & PERF_SAMPLE_CPU) 1513 size += sizeof(data->cpu_entry); 1514 1515 event->id_header_size = size; 1516 } 1517 1518 static bool perf_event_validate_size(struct perf_event *event) 1519 { 1520 /* 1521 * The values computed here will be over-written when we actually 1522 * attach the event. 1523 */ 1524 __perf_event_read_size(event, event->group_leader->nr_siblings + 1); 1525 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ); 1526 perf_event__id_header_size(event); 1527 1528 /* 1529 * Sum the lot; should not exceed the 64k limit we have on records. 1530 * Conservative limit to allow for callchains and other variable fields. 1531 */ 1532 if (event->read_size + event->header_size + 1533 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024) 1534 return false; 1535 1536 return true; 1537 } 1538 1539 static void perf_group_attach(struct perf_event *event) 1540 { 1541 struct perf_event *group_leader = event->group_leader, *pos; 1542 1543 /* 1544 * We can have double attach due to group movement in perf_event_open. 1545 */ 1546 if (event->attach_state & PERF_ATTACH_GROUP) 1547 return; 1548 1549 event->attach_state |= PERF_ATTACH_GROUP; 1550 1551 if (group_leader == event) 1552 return; 1553 1554 WARN_ON_ONCE(group_leader->ctx != event->ctx); 1555 1556 if (group_leader->group_flags & PERF_GROUP_SOFTWARE && 1557 !is_software_event(event)) 1558 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE; 1559 1560 list_add_tail(&event->group_entry, &group_leader->sibling_list); 1561 group_leader->nr_siblings++; 1562 1563 perf_event__header_size(group_leader); 1564 1565 list_for_each_entry(pos, &group_leader->sibling_list, group_entry) 1566 perf_event__header_size(pos); 1567 } 1568 1569 /* 1570 * Remove a event from the lists for its context. 1571 * Must be called with ctx->mutex and ctx->lock held. 1572 */ 1573 static void 1574 list_del_event(struct perf_event *event, struct perf_event_context *ctx) 1575 { 1576 struct perf_cpu_context *cpuctx; 1577 1578 WARN_ON_ONCE(event->ctx != ctx); 1579 lockdep_assert_held(&ctx->lock); 1580 1581 /* 1582 * We can have double detach due to exit/hot-unplug + close. 1583 */ 1584 if (!(event->attach_state & PERF_ATTACH_CONTEXT)) 1585 return; 1586 1587 event->attach_state &= ~PERF_ATTACH_CONTEXT; 1588 1589 if (is_cgroup_event(event)) { 1590 ctx->nr_cgroups--; 1591 /* 1592 * Because cgroup events are always per-cpu events, this will 1593 * always be called from the right CPU. 1594 */ 1595 cpuctx = __get_cpu_context(ctx); 1596 /* 1597 * If there are no more cgroup events then clear cgrp to avoid 1598 * stale pointer in update_cgrp_time_from_cpuctx(). 1599 */ 1600 if (!ctx->nr_cgroups) 1601 cpuctx->cgrp = NULL; 1602 } 1603 1604 ctx->nr_events--; 1605 if (event->attr.inherit_stat) 1606 ctx->nr_stat--; 1607 1608 list_del_rcu(&event->event_entry); 1609 1610 if (event->group_leader == event) 1611 list_del_init(&event->group_entry); 1612 1613 update_group_times(event); 1614 1615 /* 1616 * If event was in error state, then keep it 1617 * that way, otherwise bogus counts will be 1618 * returned on read(). The only way to get out 1619 * of error state is by explicit re-enabling 1620 * of the event 1621 */ 1622 if (event->state > PERF_EVENT_STATE_OFF) 1623 event->state = PERF_EVENT_STATE_OFF; 1624 1625 ctx->generation++; 1626 } 1627 1628 static void perf_group_detach(struct perf_event *event) 1629 { 1630 struct perf_event *sibling, *tmp; 1631 struct list_head *list = NULL; 1632 1633 /* 1634 * We can have double detach due to exit/hot-unplug + close. 1635 */ 1636 if (!(event->attach_state & PERF_ATTACH_GROUP)) 1637 return; 1638 1639 event->attach_state &= ~PERF_ATTACH_GROUP; 1640 1641 /* 1642 * If this is a sibling, remove it from its group. 1643 */ 1644 if (event->group_leader != event) { 1645 list_del_init(&event->group_entry); 1646 event->group_leader->nr_siblings--; 1647 goto out; 1648 } 1649 1650 if (!list_empty(&event->group_entry)) 1651 list = &event->group_entry; 1652 1653 /* 1654 * If this was a group event with sibling events then 1655 * upgrade the siblings to singleton events by adding them 1656 * to whatever list we are on. 1657 */ 1658 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) { 1659 if (list) 1660 list_move_tail(&sibling->group_entry, list); 1661 sibling->group_leader = sibling; 1662 1663 /* Inherit group flags from the previous leader */ 1664 sibling->group_flags = event->group_flags; 1665 1666 WARN_ON_ONCE(sibling->ctx != event->ctx); 1667 } 1668 1669 out: 1670 perf_event__header_size(event->group_leader); 1671 1672 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry) 1673 perf_event__header_size(tmp); 1674 } 1675 1676 static bool is_orphaned_event(struct perf_event *event) 1677 { 1678 return event->state == PERF_EVENT_STATE_DEAD; 1679 } 1680 1681 static inline int __pmu_filter_match(struct perf_event *event) 1682 { 1683 struct pmu *pmu = event->pmu; 1684 return pmu->filter_match ? pmu->filter_match(event) : 1; 1685 } 1686 1687 /* 1688 * Check whether we should attempt to schedule an event group based on 1689 * PMU-specific filtering. An event group can consist of HW and SW events, 1690 * potentially with a SW leader, so we must check all the filters, to 1691 * determine whether a group is schedulable: 1692 */ 1693 static inline int pmu_filter_match(struct perf_event *event) 1694 { 1695 struct perf_event *child; 1696 1697 if (!__pmu_filter_match(event)) 1698 return 0; 1699 1700 list_for_each_entry(child, &event->sibling_list, group_entry) { 1701 if (!__pmu_filter_match(child)) 1702 return 0; 1703 } 1704 1705 return 1; 1706 } 1707 1708 static inline int 1709 event_filter_match(struct perf_event *event) 1710 { 1711 return (event->cpu == -1 || event->cpu == smp_processor_id()) 1712 && perf_cgroup_match(event) && pmu_filter_match(event); 1713 } 1714 1715 static void 1716 event_sched_out(struct perf_event *event, 1717 struct perf_cpu_context *cpuctx, 1718 struct perf_event_context *ctx) 1719 { 1720 u64 tstamp = perf_event_time(event); 1721 u64 delta; 1722 1723 WARN_ON_ONCE(event->ctx != ctx); 1724 lockdep_assert_held(&ctx->lock); 1725 1726 /* 1727 * An event which could not be activated because of 1728 * filter mismatch still needs to have its timings 1729 * maintained, otherwise bogus information is return 1730 * via read() for time_enabled, time_running: 1731 */ 1732 if (event->state == PERF_EVENT_STATE_INACTIVE 1733 && !event_filter_match(event)) { 1734 delta = tstamp - event->tstamp_stopped; 1735 event->tstamp_running += delta; 1736 event->tstamp_stopped = tstamp; 1737 } 1738 1739 if (event->state != PERF_EVENT_STATE_ACTIVE) 1740 return; 1741 1742 perf_pmu_disable(event->pmu); 1743 1744 event->tstamp_stopped = tstamp; 1745 event->pmu->del(event, 0); 1746 event->oncpu = -1; 1747 event->state = PERF_EVENT_STATE_INACTIVE; 1748 if (event->pending_disable) { 1749 event->pending_disable = 0; 1750 event->state = PERF_EVENT_STATE_OFF; 1751 } 1752 1753 if (!is_software_event(event)) 1754 cpuctx->active_oncpu--; 1755 if (!--ctx->nr_active) 1756 perf_event_ctx_deactivate(ctx); 1757 if (event->attr.freq && event->attr.sample_freq) 1758 ctx->nr_freq--; 1759 if (event->attr.exclusive || !cpuctx->active_oncpu) 1760 cpuctx->exclusive = 0; 1761 1762 perf_pmu_enable(event->pmu); 1763 } 1764 1765 static void 1766 group_sched_out(struct perf_event *group_event, 1767 struct perf_cpu_context *cpuctx, 1768 struct perf_event_context *ctx) 1769 { 1770 struct perf_event *event; 1771 int state = group_event->state; 1772 1773 event_sched_out(group_event, cpuctx, ctx); 1774 1775 /* 1776 * Schedule out siblings (if any): 1777 */ 1778 list_for_each_entry(event, &group_event->sibling_list, group_entry) 1779 event_sched_out(event, cpuctx, ctx); 1780 1781 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive) 1782 cpuctx->exclusive = 0; 1783 } 1784 1785 #define DETACH_GROUP 0x01UL 1786 1787 /* 1788 * Cross CPU call to remove a performance event 1789 * 1790 * We disable the event on the hardware level first. After that we 1791 * remove it from the context list. 1792 */ 1793 static void 1794 __perf_remove_from_context(struct perf_event *event, 1795 struct perf_cpu_context *cpuctx, 1796 struct perf_event_context *ctx, 1797 void *info) 1798 { 1799 unsigned long flags = (unsigned long)info; 1800 1801 event_sched_out(event, cpuctx, ctx); 1802 if (flags & DETACH_GROUP) 1803 perf_group_detach(event); 1804 list_del_event(event, ctx); 1805 1806 if (!ctx->nr_events && ctx->is_active) { 1807 ctx->is_active = 0; 1808 if (ctx->task) { 1809 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 1810 cpuctx->task_ctx = NULL; 1811 } 1812 } 1813 } 1814 1815 /* 1816 * Remove the event from a task's (or a CPU's) list of events. 1817 * 1818 * If event->ctx is a cloned context, callers must make sure that 1819 * every task struct that event->ctx->task could possibly point to 1820 * remains valid. This is OK when called from perf_release since 1821 * that only calls us on the top-level context, which can't be a clone. 1822 * When called from perf_event_exit_task, it's OK because the 1823 * context has been detached from its task. 1824 */ 1825 static void perf_remove_from_context(struct perf_event *event, unsigned long flags) 1826 { 1827 lockdep_assert_held(&event->ctx->mutex); 1828 1829 event_function_call(event, __perf_remove_from_context, (void *)flags); 1830 } 1831 1832 /* 1833 * Cross CPU call to disable a performance event 1834 */ 1835 static void __perf_event_disable(struct perf_event *event, 1836 struct perf_cpu_context *cpuctx, 1837 struct perf_event_context *ctx, 1838 void *info) 1839 { 1840 if (event->state < PERF_EVENT_STATE_INACTIVE) 1841 return; 1842 1843 update_context_time(ctx); 1844 update_cgrp_time_from_event(event); 1845 update_group_times(event); 1846 if (event == event->group_leader) 1847 group_sched_out(event, cpuctx, ctx); 1848 else 1849 event_sched_out(event, cpuctx, ctx); 1850 event->state = PERF_EVENT_STATE_OFF; 1851 } 1852 1853 /* 1854 * Disable a event. 1855 * 1856 * If event->ctx is a cloned context, callers must make sure that 1857 * every task struct that event->ctx->task could possibly point to 1858 * remains valid. This condition is satisifed when called through 1859 * perf_event_for_each_child or perf_event_for_each because they 1860 * hold the top-level event's child_mutex, so any descendant that 1861 * goes to exit will block in perf_event_exit_event(). 1862 * 1863 * When called from perf_pending_event it's OK because event->ctx 1864 * is the current context on this CPU and preemption is disabled, 1865 * hence we can't get into perf_event_task_sched_out for this context. 1866 */ 1867 static void _perf_event_disable(struct perf_event *event) 1868 { 1869 struct perf_event_context *ctx = event->ctx; 1870 1871 raw_spin_lock_irq(&ctx->lock); 1872 if (event->state <= PERF_EVENT_STATE_OFF) { 1873 raw_spin_unlock_irq(&ctx->lock); 1874 return; 1875 } 1876 raw_spin_unlock_irq(&ctx->lock); 1877 1878 event_function_call(event, __perf_event_disable, NULL); 1879 } 1880 1881 void perf_event_disable_local(struct perf_event *event) 1882 { 1883 event_function_local(event, __perf_event_disable, NULL); 1884 } 1885 1886 /* 1887 * Strictly speaking kernel users cannot create groups and therefore this 1888 * interface does not need the perf_event_ctx_lock() magic. 1889 */ 1890 void perf_event_disable(struct perf_event *event) 1891 { 1892 struct perf_event_context *ctx; 1893 1894 ctx = perf_event_ctx_lock(event); 1895 _perf_event_disable(event); 1896 perf_event_ctx_unlock(event, ctx); 1897 } 1898 EXPORT_SYMBOL_GPL(perf_event_disable); 1899 1900 static void perf_set_shadow_time(struct perf_event *event, 1901 struct perf_event_context *ctx, 1902 u64 tstamp) 1903 { 1904 /* 1905 * use the correct time source for the time snapshot 1906 * 1907 * We could get by without this by leveraging the 1908 * fact that to get to this function, the caller 1909 * has most likely already called update_context_time() 1910 * and update_cgrp_time_xx() and thus both timestamp 1911 * are identical (or very close). Given that tstamp is, 1912 * already adjusted for cgroup, we could say that: 1913 * tstamp - ctx->timestamp 1914 * is equivalent to 1915 * tstamp - cgrp->timestamp. 1916 * 1917 * Then, in perf_output_read(), the calculation would 1918 * work with no changes because: 1919 * - event is guaranteed scheduled in 1920 * - no scheduled out in between 1921 * - thus the timestamp would be the same 1922 * 1923 * But this is a bit hairy. 1924 * 1925 * So instead, we have an explicit cgroup call to remain 1926 * within the time time source all along. We believe it 1927 * is cleaner and simpler to understand. 1928 */ 1929 if (is_cgroup_event(event)) 1930 perf_cgroup_set_shadow_time(event, tstamp); 1931 else 1932 event->shadow_ctx_time = tstamp - ctx->timestamp; 1933 } 1934 1935 #define MAX_INTERRUPTS (~0ULL) 1936 1937 static void perf_log_throttle(struct perf_event *event, int enable); 1938 static void perf_log_itrace_start(struct perf_event *event); 1939 1940 static int 1941 event_sched_in(struct perf_event *event, 1942 struct perf_cpu_context *cpuctx, 1943 struct perf_event_context *ctx) 1944 { 1945 u64 tstamp = perf_event_time(event); 1946 int ret = 0; 1947 1948 lockdep_assert_held(&ctx->lock); 1949 1950 if (event->state <= PERF_EVENT_STATE_OFF) 1951 return 0; 1952 1953 WRITE_ONCE(event->oncpu, smp_processor_id()); 1954 /* 1955 * Order event::oncpu write to happen before the ACTIVE state 1956 * is visible. 1957 */ 1958 smp_wmb(); 1959 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE); 1960 1961 /* 1962 * Unthrottle events, since we scheduled we might have missed several 1963 * ticks already, also for a heavily scheduling task there is little 1964 * guarantee it'll get a tick in a timely manner. 1965 */ 1966 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) { 1967 perf_log_throttle(event, 1); 1968 event->hw.interrupts = 0; 1969 } 1970 1971 /* 1972 * The new state must be visible before we turn it on in the hardware: 1973 */ 1974 smp_wmb(); 1975 1976 perf_pmu_disable(event->pmu); 1977 1978 perf_set_shadow_time(event, ctx, tstamp); 1979 1980 perf_log_itrace_start(event); 1981 1982 if (event->pmu->add(event, PERF_EF_START)) { 1983 event->state = PERF_EVENT_STATE_INACTIVE; 1984 event->oncpu = -1; 1985 ret = -EAGAIN; 1986 goto out; 1987 } 1988 1989 event->tstamp_running += tstamp - event->tstamp_stopped; 1990 1991 if (!is_software_event(event)) 1992 cpuctx->active_oncpu++; 1993 if (!ctx->nr_active++) 1994 perf_event_ctx_activate(ctx); 1995 if (event->attr.freq && event->attr.sample_freq) 1996 ctx->nr_freq++; 1997 1998 if (event->attr.exclusive) 1999 cpuctx->exclusive = 1; 2000 2001 out: 2002 perf_pmu_enable(event->pmu); 2003 2004 return ret; 2005 } 2006 2007 static int 2008 group_sched_in(struct perf_event *group_event, 2009 struct perf_cpu_context *cpuctx, 2010 struct perf_event_context *ctx) 2011 { 2012 struct perf_event *event, *partial_group = NULL; 2013 struct pmu *pmu = ctx->pmu; 2014 u64 now = ctx->time; 2015 bool simulate = false; 2016 2017 if (group_event->state == PERF_EVENT_STATE_OFF) 2018 return 0; 2019 2020 pmu->start_txn(pmu, PERF_PMU_TXN_ADD); 2021 2022 if (event_sched_in(group_event, cpuctx, ctx)) { 2023 pmu->cancel_txn(pmu); 2024 perf_mux_hrtimer_restart(cpuctx); 2025 return -EAGAIN; 2026 } 2027 2028 /* 2029 * Schedule in siblings as one group (if any): 2030 */ 2031 list_for_each_entry(event, &group_event->sibling_list, group_entry) { 2032 if (event_sched_in(event, cpuctx, ctx)) { 2033 partial_group = event; 2034 goto group_error; 2035 } 2036 } 2037 2038 if (!pmu->commit_txn(pmu)) 2039 return 0; 2040 2041 group_error: 2042 /* 2043 * Groups can be scheduled in as one unit only, so undo any 2044 * partial group before returning: 2045 * The events up to the failed event are scheduled out normally, 2046 * tstamp_stopped will be updated. 2047 * 2048 * The failed events and the remaining siblings need to have 2049 * their timings updated as if they had gone thru event_sched_in() 2050 * and event_sched_out(). This is required to get consistent timings 2051 * across the group. This also takes care of the case where the group 2052 * could never be scheduled by ensuring tstamp_stopped is set to mark 2053 * the time the event was actually stopped, such that time delta 2054 * calculation in update_event_times() is correct. 2055 */ 2056 list_for_each_entry(event, &group_event->sibling_list, group_entry) { 2057 if (event == partial_group) 2058 simulate = true; 2059 2060 if (simulate) { 2061 event->tstamp_running += now - event->tstamp_stopped; 2062 event->tstamp_stopped = now; 2063 } else { 2064 event_sched_out(event, cpuctx, ctx); 2065 } 2066 } 2067 event_sched_out(group_event, cpuctx, ctx); 2068 2069 pmu->cancel_txn(pmu); 2070 2071 perf_mux_hrtimer_restart(cpuctx); 2072 2073 return -EAGAIN; 2074 } 2075 2076 /* 2077 * Work out whether we can put this event group on the CPU now. 2078 */ 2079 static int group_can_go_on(struct perf_event *event, 2080 struct perf_cpu_context *cpuctx, 2081 int can_add_hw) 2082 { 2083 /* 2084 * Groups consisting entirely of software events can always go on. 2085 */ 2086 if (event->group_flags & PERF_GROUP_SOFTWARE) 2087 return 1; 2088 /* 2089 * If an exclusive group is already on, no other hardware 2090 * events can go on. 2091 */ 2092 if (cpuctx->exclusive) 2093 return 0; 2094 /* 2095 * If this group is exclusive and there are already 2096 * events on the CPU, it can't go on. 2097 */ 2098 if (event->attr.exclusive && cpuctx->active_oncpu) 2099 return 0; 2100 /* 2101 * Otherwise, try to add it if all previous groups were able 2102 * to go on. 2103 */ 2104 return can_add_hw; 2105 } 2106 2107 static void add_event_to_ctx(struct perf_event *event, 2108 struct perf_event_context *ctx) 2109 { 2110 u64 tstamp = perf_event_time(event); 2111 2112 list_add_event(event, ctx); 2113 perf_group_attach(event); 2114 event->tstamp_enabled = tstamp; 2115 event->tstamp_running = tstamp; 2116 event->tstamp_stopped = tstamp; 2117 } 2118 2119 static void ctx_sched_out(struct perf_event_context *ctx, 2120 struct perf_cpu_context *cpuctx, 2121 enum event_type_t event_type); 2122 static void 2123 ctx_sched_in(struct perf_event_context *ctx, 2124 struct perf_cpu_context *cpuctx, 2125 enum event_type_t event_type, 2126 struct task_struct *task); 2127 2128 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx, 2129 struct perf_event_context *ctx) 2130 { 2131 if (!cpuctx->task_ctx) 2132 return; 2133 2134 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx)) 2135 return; 2136 2137 ctx_sched_out(ctx, cpuctx, EVENT_ALL); 2138 } 2139 2140 static void perf_event_sched_in(struct perf_cpu_context *cpuctx, 2141 struct perf_event_context *ctx, 2142 struct task_struct *task) 2143 { 2144 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task); 2145 if (ctx) 2146 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task); 2147 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task); 2148 if (ctx) 2149 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task); 2150 } 2151 2152 static void ctx_resched(struct perf_cpu_context *cpuctx, 2153 struct perf_event_context *task_ctx) 2154 { 2155 perf_pmu_disable(cpuctx->ctx.pmu); 2156 if (task_ctx) 2157 task_ctx_sched_out(cpuctx, task_ctx); 2158 cpu_ctx_sched_out(cpuctx, EVENT_ALL); 2159 perf_event_sched_in(cpuctx, task_ctx, current); 2160 perf_pmu_enable(cpuctx->ctx.pmu); 2161 } 2162 2163 /* 2164 * Cross CPU call to install and enable a performance event 2165 * 2166 * Very similar to remote_function() + event_function() but cannot assume that 2167 * things like ctx->is_active and cpuctx->task_ctx are set. 2168 */ 2169 static int __perf_install_in_context(void *info) 2170 { 2171 struct perf_event *event = info; 2172 struct perf_event_context *ctx = event->ctx; 2173 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 2174 struct perf_event_context *task_ctx = cpuctx->task_ctx; 2175 bool activate = true; 2176 int ret = 0; 2177 2178 raw_spin_lock(&cpuctx->ctx.lock); 2179 if (ctx->task) { 2180 raw_spin_lock(&ctx->lock); 2181 task_ctx = ctx; 2182 2183 /* If we're on the wrong CPU, try again */ 2184 if (task_cpu(ctx->task) != smp_processor_id()) { 2185 ret = -ESRCH; 2186 goto unlock; 2187 } 2188 2189 /* 2190 * If we're on the right CPU, see if the task we target is 2191 * current, if not we don't have to activate the ctx, a future 2192 * context switch will do that for us. 2193 */ 2194 if (ctx->task != current) 2195 activate = false; 2196 else 2197 WARN_ON_ONCE(cpuctx->task_ctx && cpuctx->task_ctx != ctx); 2198 2199 } else if (task_ctx) { 2200 raw_spin_lock(&task_ctx->lock); 2201 } 2202 2203 if (activate) { 2204 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 2205 add_event_to_ctx(event, ctx); 2206 ctx_resched(cpuctx, task_ctx); 2207 } else { 2208 add_event_to_ctx(event, ctx); 2209 } 2210 2211 unlock: 2212 perf_ctx_unlock(cpuctx, task_ctx); 2213 2214 return ret; 2215 } 2216 2217 /* 2218 * Attach a performance event to a context. 2219 * 2220 * Very similar to event_function_call, see comment there. 2221 */ 2222 static void 2223 perf_install_in_context(struct perf_event_context *ctx, 2224 struct perf_event *event, 2225 int cpu) 2226 { 2227 struct task_struct *task = READ_ONCE(ctx->task); 2228 2229 lockdep_assert_held(&ctx->mutex); 2230 2231 event->ctx = ctx; 2232 if (event->cpu != -1) 2233 event->cpu = cpu; 2234 2235 if (!task) { 2236 cpu_function_call(cpu, __perf_install_in_context, event); 2237 return; 2238 } 2239 2240 /* 2241 * Should not happen, we validate the ctx is still alive before calling. 2242 */ 2243 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) 2244 return; 2245 2246 /* 2247 * Installing events is tricky because we cannot rely on ctx->is_active 2248 * to be set in case this is the nr_events 0 -> 1 transition. 2249 */ 2250 again: 2251 /* 2252 * Cannot use task_function_call() because we need to run on the task's 2253 * CPU regardless of whether its current or not. 2254 */ 2255 if (!cpu_function_call(task_cpu(task), __perf_install_in_context, event)) 2256 return; 2257 2258 raw_spin_lock_irq(&ctx->lock); 2259 task = ctx->task; 2260 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) { 2261 /* 2262 * Cannot happen because we already checked above (which also 2263 * cannot happen), and we hold ctx->mutex, which serializes us 2264 * against perf_event_exit_task_context(). 2265 */ 2266 raw_spin_unlock_irq(&ctx->lock); 2267 return; 2268 } 2269 raw_spin_unlock_irq(&ctx->lock); 2270 /* 2271 * Since !ctx->is_active doesn't mean anything, we must IPI 2272 * unconditionally. 2273 */ 2274 goto again; 2275 } 2276 2277 /* 2278 * Put a event into inactive state and update time fields. 2279 * Enabling the leader of a group effectively enables all 2280 * the group members that aren't explicitly disabled, so we 2281 * have to update their ->tstamp_enabled also. 2282 * Note: this works for group members as well as group leaders 2283 * since the non-leader members' sibling_lists will be empty. 2284 */ 2285 static void __perf_event_mark_enabled(struct perf_event *event) 2286 { 2287 struct perf_event *sub; 2288 u64 tstamp = perf_event_time(event); 2289 2290 event->state = PERF_EVENT_STATE_INACTIVE; 2291 event->tstamp_enabled = tstamp - event->total_time_enabled; 2292 list_for_each_entry(sub, &event->sibling_list, group_entry) { 2293 if (sub->state >= PERF_EVENT_STATE_INACTIVE) 2294 sub->tstamp_enabled = tstamp - sub->total_time_enabled; 2295 } 2296 } 2297 2298 /* 2299 * Cross CPU call to enable a performance event 2300 */ 2301 static void __perf_event_enable(struct perf_event *event, 2302 struct perf_cpu_context *cpuctx, 2303 struct perf_event_context *ctx, 2304 void *info) 2305 { 2306 struct perf_event *leader = event->group_leader; 2307 struct perf_event_context *task_ctx; 2308 2309 if (event->state >= PERF_EVENT_STATE_INACTIVE || 2310 event->state <= PERF_EVENT_STATE_ERROR) 2311 return; 2312 2313 if (ctx->is_active) 2314 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 2315 2316 __perf_event_mark_enabled(event); 2317 2318 if (!ctx->is_active) 2319 return; 2320 2321 if (!event_filter_match(event)) { 2322 if (is_cgroup_event(event)) 2323 perf_cgroup_defer_enabled(event); 2324 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current); 2325 return; 2326 } 2327 2328 /* 2329 * If the event is in a group and isn't the group leader, 2330 * then don't put it on unless the group is on. 2331 */ 2332 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) { 2333 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current); 2334 return; 2335 } 2336 2337 task_ctx = cpuctx->task_ctx; 2338 if (ctx->task) 2339 WARN_ON_ONCE(task_ctx != ctx); 2340 2341 ctx_resched(cpuctx, task_ctx); 2342 } 2343 2344 /* 2345 * Enable a event. 2346 * 2347 * If event->ctx is a cloned context, callers must make sure that 2348 * every task struct that event->ctx->task could possibly point to 2349 * remains valid. This condition is satisfied when called through 2350 * perf_event_for_each_child or perf_event_for_each as described 2351 * for perf_event_disable. 2352 */ 2353 static void _perf_event_enable(struct perf_event *event) 2354 { 2355 struct perf_event_context *ctx = event->ctx; 2356 2357 raw_spin_lock_irq(&ctx->lock); 2358 if (event->state >= PERF_EVENT_STATE_INACTIVE || 2359 event->state < PERF_EVENT_STATE_ERROR) { 2360 raw_spin_unlock_irq(&ctx->lock); 2361 return; 2362 } 2363 2364 /* 2365 * If the event is in error state, clear that first. 2366 * 2367 * That way, if we see the event in error state below, we know that it 2368 * has gone back into error state, as distinct from the task having 2369 * been scheduled away before the cross-call arrived. 2370 */ 2371 if (event->state == PERF_EVENT_STATE_ERROR) 2372 event->state = PERF_EVENT_STATE_OFF; 2373 raw_spin_unlock_irq(&ctx->lock); 2374 2375 event_function_call(event, __perf_event_enable, NULL); 2376 } 2377 2378 /* 2379 * See perf_event_disable(); 2380 */ 2381 void perf_event_enable(struct perf_event *event) 2382 { 2383 struct perf_event_context *ctx; 2384 2385 ctx = perf_event_ctx_lock(event); 2386 _perf_event_enable(event); 2387 perf_event_ctx_unlock(event, ctx); 2388 } 2389 EXPORT_SYMBOL_GPL(perf_event_enable); 2390 2391 struct stop_event_data { 2392 struct perf_event *event; 2393 unsigned int restart; 2394 }; 2395 2396 static int __perf_event_stop(void *info) 2397 { 2398 struct stop_event_data *sd = info; 2399 struct perf_event *event = sd->event; 2400 2401 /* if it's already INACTIVE, do nothing */ 2402 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) 2403 return 0; 2404 2405 /* matches smp_wmb() in event_sched_in() */ 2406 smp_rmb(); 2407 2408 /* 2409 * There is a window with interrupts enabled before we get here, 2410 * so we need to check again lest we try to stop another CPU's event. 2411 */ 2412 if (READ_ONCE(event->oncpu) != smp_processor_id()) 2413 return -EAGAIN; 2414 2415 event->pmu->stop(event, PERF_EF_UPDATE); 2416 2417 /* 2418 * May race with the actual stop (through perf_pmu_output_stop()), 2419 * but it is only used for events with AUX ring buffer, and such 2420 * events will refuse to restart because of rb::aux_mmap_count==0, 2421 * see comments in perf_aux_output_begin(). 2422 * 2423 * Since this is happening on a event-local CPU, no trace is lost 2424 * while restarting. 2425 */ 2426 if (sd->restart) 2427 event->pmu->start(event, PERF_EF_START); 2428 2429 return 0; 2430 } 2431 2432 static int perf_event_restart(struct perf_event *event) 2433 { 2434 struct stop_event_data sd = { 2435 .event = event, 2436 .restart = 1, 2437 }; 2438 int ret = 0; 2439 2440 do { 2441 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) 2442 return 0; 2443 2444 /* matches smp_wmb() in event_sched_in() */ 2445 smp_rmb(); 2446 2447 /* 2448 * We only want to restart ACTIVE events, so if the event goes 2449 * inactive here (event->oncpu==-1), there's nothing more to do; 2450 * fall through with ret==-ENXIO. 2451 */ 2452 ret = cpu_function_call(READ_ONCE(event->oncpu), 2453 __perf_event_stop, &sd); 2454 } while (ret == -EAGAIN); 2455 2456 return ret; 2457 } 2458 2459 /* 2460 * In order to contain the amount of racy and tricky in the address filter 2461 * configuration management, it is a two part process: 2462 * 2463 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below, 2464 * we update the addresses of corresponding vmas in 2465 * event::addr_filters_offs array and bump the event::addr_filters_gen; 2466 * (p2) when an event is scheduled in (pmu::add), it calls 2467 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync() 2468 * if the generation has changed since the previous call. 2469 * 2470 * If (p1) happens while the event is active, we restart it to force (p2). 2471 * 2472 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on 2473 * pre-existing mappings, called once when new filters arrive via SET_FILTER 2474 * ioctl; 2475 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly 2476 * registered mapping, called for every new mmap(), with mm::mmap_sem down 2477 * for reading; 2478 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process 2479 * of exec. 2480 */ 2481 void perf_event_addr_filters_sync(struct perf_event *event) 2482 { 2483 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 2484 2485 if (!has_addr_filter(event)) 2486 return; 2487 2488 raw_spin_lock(&ifh->lock); 2489 if (event->addr_filters_gen != event->hw.addr_filters_gen) { 2490 event->pmu->addr_filters_sync(event); 2491 event->hw.addr_filters_gen = event->addr_filters_gen; 2492 } 2493 raw_spin_unlock(&ifh->lock); 2494 } 2495 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync); 2496 2497 static int _perf_event_refresh(struct perf_event *event, int refresh) 2498 { 2499 /* 2500 * not supported on inherited events 2501 */ 2502 if (event->attr.inherit || !is_sampling_event(event)) 2503 return -EINVAL; 2504 2505 atomic_add(refresh, &event->event_limit); 2506 _perf_event_enable(event); 2507 2508 return 0; 2509 } 2510 2511 /* 2512 * See perf_event_disable() 2513 */ 2514 int perf_event_refresh(struct perf_event *event, int refresh) 2515 { 2516 struct perf_event_context *ctx; 2517 int ret; 2518 2519 ctx = perf_event_ctx_lock(event); 2520 ret = _perf_event_refresh(event, refresh); 2521 perf_event_ctx_unlock(event, ctx); 2522 2523 return ret; 2524 } 2525 EXPORT_SYMBOL_GPL(perf_event_refresh); 2526 2527 static void ctx_sched_out(struct perf_event_context *ctx, 2528 struct perf_cpu_context *cpuctx, 2529 enum event_type_t event_type) 2530 { 2531 int is_active = ctx->is_active; 2532 struct perf_event *event; 2533 2534 lockdep_assert_held(&ctx->lock); 2535 2536 if (likely(!ctx->nr_events)) { 2537 /* 2538 * See __perf_remove_from_context(). 2539 */ 2540 WARN_ON_ONCE(ctx->is_active); 2541 if (ctx->task) 2542 WARN_ON_ONCE(cpuctx->task_ctx); 2543 return; 2544 } 2545 2546 ctx->is_active &= ~event_type; 2547 if (!(ctx->is_active & EVENT_ALL)) 2548 ctx->is_active = 0; 2549 2550 if (ctx->task) { 2551 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 2552 if (!ctx->is_active) 2553 cpuctx->task_ctx = NULL; 2554 } 2555 2556 /* 2557 * Always update time if it was set; not only when it changes. 2558 * Otherwise we can 'forget' to update time for any but the last 2559 * context we sched out. For example: 2560 * 2561 * ctx_sched_out(.event_type = EVENT_FLEXIBLE) 2562 * ctx_sched_out(.event_type = EVENT_PINNED) 2563 * 2564 * would only update time for the pinned events. 2565 */ 2566 if (is_active & EVENT_TIME) { 2567 /* update (and stop) ctx time */ 2568 update_context_time(ctx); 2569 update_cgrp_time_from_cpuctx(cpuctx); 2570 } 2571 2572 is_active ^= ctx->is_active; /* changed bits */ 2573 2574 if (!ctx->nr_active || !(is_active & EVENT_ALL)) 2575 return; 2576 2577 perf_pmu_disable(ctx->pmu); 2578 if (is_active & EVENT_PINNED) { 2579 list_for_each_entry(event, &ctx->pinned_groups, group_entry) 2580 group_sched_out(event, cpuctx, ctx); 2581 } 2582 2583 if (is_active & EVENT_FLEXIBLE) { 2584 list_for_each_entry(event, &ctx->flexible_groups, group_entry) 2585 group_sched_out(event, cpuctx, ctx); 2586 } 2587 perf_pmu_enable(ctx->pmu); 2588 } 2589 2590 /* 2591 * Test whether two contexts are equivalent, i.e. whether they have both been 2592 * cloned from the same version of the same context. 2593 * 2594 * Equivalence is measured using a generation number in the context that is 2595 * incremented on each modification to it; see unclone_ctx(), list_add_event() 2596 * and list_del_event(). 2597 */ 2598 static int context_equiv(struct perf_event_context *ctx1, 2599 struct perf_event_context *ctx2) 2600 { 2601 lockdep_assert_held(&ctx1->lock); 2602 lockdep_assert_held(&ctx2->lock); 2603 2604 /* Pinning disables the swap optimization */ 2605 if (ctx1->pin_count || ctx2->pin_count) 2606 return 0; 2607 2608 /* If ctx1 is the parent of ctx2 */ 2609 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen) 2610 return 1; 2611 2612 /* If ctx2 is the parent of ctx1 */ 2613 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation) 2614 return 1; 2615 2616 /* 2617 * If ctx1 and ctx2 have the same parent; we flatten the parent 2618 * hierarchy, see perf_event_init_context(). 2619 */ 2620 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx && 2621 ctx1->parent_gen == ctx2->parent_gen) 2622 return 1; 2623 2624 /* Unmatched */ 2625 return 0; 2626 } 2627 2628 static void __perf_event_sync_stat(struct perf_event *event, 2629 struct perf_event *next_event) 2630 { 2631 u64 value; 2632 2633 if (!event->attr.inherit_stat) 2634 return; 2635 2636 /* 2637 * Update the event value, we cannot use perf_event_read() 2638 * because we're in the middle of a context switch and have IRQs 2639 * disabled, which upsets smp_call_function_single(), however 2640 * we know the event must be on the current CPU, therefore we 2641 * don't need to use it. 2642 */ 2643 switch (event->state) { 2644 case PERF_EVENT_STATE_ACTIVE: 2645 event->pmu->read(event); 2646 /* fall-through */ 2647 2648 case PERF_EVENT_STATE_INACTIVE: 2649 update_event_times(event); 2650 break; 2651 2652 default: 2653 break; 2654 } 2655 2656 /* 2657 * In order to keep per-task stats reliable we need to flip the event 2658 * values when we flip the contexts. 2659 */ 2660 value = local64_read(&next_event->count); 2661 value = local64_xchg(&event->count, value); 2662 local64_set(&next_event->count, value); 2663 2664 swap(event->total_time_enabled, next_event->total_time_enabled); 2665 swap(event->total_time_running, next_event->total_time_running); 2666 2667 /* 2668 * Since we swizzled the values, update the user visible data too. 2669 */ 2670 perf_event_update_userpage(event); 2671 perf_event_update_userpage(next_event); 2672 } 2673 2674 static void perf_event_sync_stat(struct perf_event_context *ctx, 2675 struct perf_event_context *next_ctx) 2676 { 2677 struct perf_event *event, *next_event; 2678 2679 if (!ctx->nr_stat) 2680 return; 2681 2682 update_context_time(ctx); 2683 2684 event = list_first_entry(&ctx->event_list, 2685 struct perf_event, event_entry); 2686 2687 next_event = list_first_entry(&next_ctx->event_list, 2688 struct perf_event, event_entry); 2689 2690 while (&event->event_entry != &ctx->event_list && 2691 &next_event->event_entry != &next_ctx->event_list) { 2692 2693 __perf_event_sync_stat(event, next_event); 2694 2695 event = list_next_entry(event, event_entry); 2696 next_event = list_next_entry(next_event, event_entry); 2697 } 2698 } 2699 2700 static void perf_event_context_sched_out(struct task_struct *task, int ctxn, 2701 struct task_struct *next) 2702 { 2703 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn]; 2704 struct perf_event_context *next_ctx; 2705 struct perf_event_context *parent, *next_parent; 2706 struct perf_cpu_context *cpuctx; 2707 int do_switch = 1; 2708 2709 if (likely(!ctx)) 2710 return; 2711 2712 cpuctx = __get_cpu_context(ctx); 2713 if (!cpuctx->task_ctx) 2714 return; 2715 2716 rcu_read_lock(); 2717 next_ctx = next->perf_event_ctxp[ctxn]; 2718 if (!next_ctx) 2719 goto unlock; 2720 2721 parent = rcu_dereference(ctx->parent_ctx); 2722 next_parent = rcu_dereference(next_ctx->parent_ctx); 2723 2724 /* If neither context have a parent context; they cannot be clones. */ 2725 if (!parent && !next_parent) 2726 goto unlock; 2727 2728 if (next_parent == ctx || next_ctx == parent || next_parent == parent) { 2729 /* 2730 * Looks like the two contexts are clones, so we might be 2731 * able to optimize the context switch. We lock both 2732 * contexts and check that they are clones under the 2733 * lock (including re-checking that neither has been 2734 * uncloned in the meantime). It doesn't matter which 2735 * order we take the locks because no other cpu could 2736 * be trying to lock both of these tasks. 2737 */ 2738 raw_spin_lock(&ctx->lock); 2739 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING); 2740 if (context_equiv(ctx, next_ctx)) { 2741 WRITE_ONCE(ctx->task, next); 2742 WRITE_ONCE(next_ctx->task, task); 2743 2744 swap(ctx->task_ctx_data, next_ctx->task_ctx_data); 2745 2746 /* 2747 * RCU_INIT_POINTER here is safe because we've not 2748 * modified the ctx and the above modification of 2749 * ctx->task and ctx->task_ctx_data are immaterial 2750 * since those values are always verified under 2751 * ctx->lock which we're now holding. 2752 */ 2753 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx); 2754 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx); 2755 2756 do_switch = 0; 2757 2758 perf_event_sync_stat(ctx, next_ctx); 2759 } 2760 raw_spin_unlock(&next_ctx->lock); 2761 raw_spin_unlock(&ctx->lock); 2762 } 2763 unlock: 2764 rcu_read_unlock(); 2765 2766 if (do_switch) { 2767 raw_spin_lock(&ctx->lock); 2768 task_ctx_sched_out(cpuctx, ctx); 2769 raw_spin_unlock(&ctx->lock); 2770 } 2771 } 2772 2773 void perf_sched_cb_dec(struct pmu *pmu) 2774 { 2775 this_cpu_dec(perf_sched_cb_usages); 2776 } 2777 2778 void perf_sched_cb_inc(struct pmu *pmu) 2779 { 2780 this_cpu_inc(perf_sched_cb_usages); 2781 } 2782 2783 /* 2784 * This function provides the context switch callback to the lower code 2785 * layer. It is invoked ONLY when the context switch callback is enabled. 2786 */ 2787 static void perf_pmu_sched_task(struct task_struct *prev, 2788 struct task_struct *next, 2789 bool sched_in) 2790 { 2791 struct perf_cpu_context *cpuctx; 2792 struct pmu *pmu; 2793 unsigned long flags; 2794 2795 if (prev == next) 2796 return; 2797 2798 local_irq_save(flags); 2799 2800 rcu_read_lock(); 2801 2802 list_for_each_entry_rcu(pmu, &pmus, entry) { 2803 if (pmu->sched_task) { 2804 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 2805 2806 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 2807 2808 perf_pmu_disable(pmu); 2809 2810 pmu->sched_task(cpuctx->task_ctx, sched_in); 2811 2812 perf_pmu_enable(pmu); 2813 2814 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 2815 } 2816 } 2817 2818 rcu_read_unlock(); 2819 2820 local_irq_restore(flags); 2821 } 2822 2823 static void perf_event_switch(struct task_struct *task, 2824 struct task_struct *next_prev, bool sched_in); 2825 2826 #define for_each_task_context_nr(ctxn) \ 2827 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++) 2828 2829 /* 2830 * Called from scheduler to remove the events of the current task, 2831 * with interrupts disabled. 2832 * 2833 * We stop each event and update the event value in event->count. 2834 * 2835 * This does not protect us against NMI, but disable() 2836 * sets the disabled bit in the control field of event _before_ 2837 * accessing the event control register. If a NMI hits, then it will 2838 * not restart the event. 2839 */ 2840 void __perf_event_task_sched_out(struct task_struct *task, 2841 struct task_struct *next) 2842 { 2843 int ctxn; 2844 2845 if (__this_cpu_read(perf_sched_cb_usages)) 2846 perf_pmu_sched_task(task, next, false); 2847 2848 if (atomic_read(&nr_switch_events)) 2849 perf_event_switch(task, next, false); 2850 2851 for_each_task_context_nr(ctxn) 2852 perf_event_context_sched_out(task, ctxn, next); 2853 2854 /* 2855 * if cgroup events exist on this CPU, then we need 2856 * to check if we have to switch out PMU state. 2857 * cgroup event are system-wide mode only 2858 */ 2859 if (atomic_read(this_cpu_ptr(&perf_cgroup_events))) 2860 perf_cgroup_sched_out(task, next); 2861 } 2862 2863 /* 2864 * Called with IRQs disabled 2865 */ 2866 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, 2867 enum event_type_t event_type) 2868 { 2869 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type); 2870 } 2871 2872 static void 2873 ctx_pinned_sched_in(struct perf_event_context *ctx, 2874 struct perf_cpu_context *cpuctx) 2875 { 2876 struct perf_event *event; 2877 2878 list_for_each_entry(event, &ctx->pinned_groups, group_entry) { 2879 if (event->state <= PERF_EVENT_STATE_OFF) 2880 continue; 2881 if (!event_filter_match(event)) 2882 continue; 2883 2884 /* may need to reset tstamp_enabled */ 2885 if (is_cgroup_event(event)) 2886 perf_cgroup_mark_enabled(event, ctx); 2887 2888 if (group_can_go_on(event, cpuctx, 1)) 2889 group_sched_in(event, cpuctx, ctx); 2890 2891 /* 2892 * If this pinned group hasn't been scheduled, 2893 * put it in error state. 2894 */ 2895 if (event->state == PERF_EVENT_STATE_INACTIVE) { 2896 update_group_times(event); 2897 event->state = PERF_EVENT_STATE_ERROR; 2898 } 2899 } 2900 } 2901 2902 static void 2903 ctx_flexible_sched_in(struct perf_event_context *ctx, 2904 struct perf_cpu_context *cpuctx) 2905 { 2906 struct perf_event *event; 2907 int can_add_hw = 1; 2908 2909 list_for_each_entry(event, &ctx->flexible_groups, group_entry) { 2910 /* Ignore events in OFF or ERROR state */ 2911 if (event->state <= PERF_EVENT_STATE_OFF) 2912 continue; 2913 /* 2914 * Listen to the 'cpu' scheduling filter constraint 2915 * of events: 2916 */ 2917 if (!event_filter_match(event)) 2918 continue; 2919 2920 /* may need to reset tstamp_enabled */ 2921 if (is_cgroup_event(event)) 2922 perf_cgroup_mark_enabled(event, ctx); 2923 2924 if (group_can_go_on(event, cpuctx, can_add_hw)) { 2925 if (group_sched_in(event, cpuctx, ctx)) 2926 can_add_hw = 0; 2927 } 2928 } 2929 } 2930 2931 static void 2932 ctx_sched_in(struct perf_event_context *ctx, 2933 struct perf_cpu_context *cpuctx, 2934 enum event_type_t event_type, 2935 struct task_struct *task) 2936 { 2937 int is_active = ctx->is_active; 2938 u64 now; 2939 2940 lockdep_assert_held(&ctx->lock); 2941 2942 if (likely(!ctx->nr_events)) 2943 return; 2944 2945 ctx->is_active |= (event_type | EVENT_TIME); 2946 if (ctx->task) { 2947 if (!is_active) 2948 cpuctx->task_ctx = ctx; 2949 else 2950 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 2951 } 2952 2953 is_active ^= ctx->is_active; /* changed bits */ 2954 2955 if (is_active & EVENT_TIME) { 2956 /* start ctx time */ 2957 now = perf_clock(); 2958 ctx->timestamp = now; 2959 perf_cgroup_set_timestamp(task, ctx); 2960 } 2961 2962 /* 2963 * First go through the list and put on any pinned groups 2964 * in order to give them the best chance of going on. 2965 */ 2966 if (is_active & EVENT_PINNED) 2967 ctx_pinned_sched_in(ctx, cpuctx); 2968 2969 /* Then walk through the lower prio flexible groups */ 2970 if (is_active & EVENT_FLEXIBLE) 2971 ctx_flexible_sched_in(ctx, cpuctx); 2972 } 2973 2974 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, 2975 enum event_type_t event_type, 2976 struct task_struct *task) 2977 { 2978 struct perf_event_context *ctx = &cpuctx->ctx; 2979 2980 ctx_sched_in(ctx, cpuctx, event_type, task); 2981 } 2982 2983 static void perf_event_context_sched_in(struct perf_event_context *ctx, 2984 struct task_struct *task) 2985 { 2986 struct perf_cpu_context *cpuctx; 2987 2988 cpuctx = __get_cpu_context(ctx); 2989 if (cpuctx->task_ctx == ctx) 2990 return; 2991 2992 perf_ctx_lock(cpuctx, ctx); 2993 perf_pmu_disable(ctx->pmu); 2994 /* 2995 * We want to keep the following priority order: 2996 * cpu pinned (that don't need to move), task pinned, 2997 * cpu flexible, task flexible. 2998 */ 2999 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); 3000 perf_event_sched_in(cpuctx, ctx, task); 3001 perf_pmu_enable(ctx->pmu); 3002 perf_ctx_unlock(cpuctx, ctx); 3003 } 3004 3005 /* 3006 * Called from scheduler to add the events of the current task 3007 * with interrupts disabled. 3008 * 3009 * We restore the event value and then enable it. 3010 * 3011 * This does not protect us against NMI, but enable() 3012 * sets the enabled bit in the control field of event _before_ 3013 * accessing the event control register. If a NMI hits, then it will 3014 * keep the event running. 3015 */ 3016 void __perf_event_task_sched_in(struct task_struct *prev, 3017 struct task_struct *task) 3018 { 3019 struct perf_event_context *ctx; 3020 int ctxn; 3021 3022 /* 3023 * If cgroup events exist on this CPU, then we need to check if we have 3024 * to switch in PMU state; cgroup event are system-wide mode only. 3025 * 3026 * Since cgroup events are CPU events, we must schedule these in before 3027 * we schedule in the task events. 3028 */ 3029 if (atomic_read(this_cpu_ptr(&perf_cgroup_events))) 3030 perf_cgroup_sched_in(prev, task); 3031 3032 for_each_task_context_nr(ctxn) { 3033 ctx = task->perf_event_ctxp[ctxn]; 3034 if (likely(!ctx)) 3035 continue; 3036 3037 perf_event_context_sched_in(ctx, task); 3038 } 3039 3040 if (atomic_read(&nr_switch_events)) 3041 perf_event_switch(task, prev, true); 3042 3043 if (__this_cpu_read(perf_sched_cb_usages)) 3044 perf_pmu_sched_task(prev, task, true); 3045 } 3046 3047 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count) 3048 { 3049 u64 frequency = event->attr.sample_freq; 3050 u64 sec = NSEC_PER_SEC; 3051 u64 divisor, dividend; 3052 3053 int count_fls, nsec_fls, frequency_fls, sec_fls; 3054 3055 count_fls = fls64(count); 3056 nsec_fls = fls64(nsec); 3057 frequency_fls = fls64(frequency); 3058 sec_fls = 30; 3059 3060 /* 3061 * We got @count in @nsec, with a target of sample_freq HZ 3062 * the target period becomes: 3063 * 3064 * @count * 10^9 3065 * period = ------------------- 3066 * @nsec * sample_freq 3067 * 3068 */ 3069 3070 /* 3071 * Reduce accuracy by one bit such that @a and @b converge 3072 * to a similar magnitude. 3073 */ 3074 #define REDUCE_FLS(a, b) \ 3075 do { \ 3076 if (a##_fls > b##_fls) { \ 3077 a >>= 1; \ 3078 a##_fls--; \ 3079 } else { \ 3080 b >>= 1; \ 3081 b##_fls--; \ 3082 } \ 3083 } while (0) 3084 3085 /* 3086 * Reduce accuracy until either term fits in a u64, then proceed with 3087 * the other, so that finally we can do a u64/u64 division. 3088 */ 3089 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) { 3090 REDUCE_FLS(nsec, frequency); 3091 REDUCE_FLS(sec, count); 3092 } 3093 3094 if (count_fls + sec_fls > 64) { 3095 divisor = nsec * frequency; 3096 3097 while (count_fls + sec_fls > 64) { 3098 REDUCE_FLS(count, sec); 3099 divisor >>= 1; 3100 } 3101 3102 dividend = count * sec; 3103 } else { 3104 dividend = count * sec; 3105 3106 while (nsec_fls + frequency_fls > 64) { 3107 REDUCE_FLS(nsec, frequency); 3108 dividend >>= 1; 3109 } 3110 3111 divisor = nsec * frequency; 3112 } 3113 3114 if (!divisor) 3115 return dividend; 3116 3117 return div64_u64(dividend, divisor); 3118 } 3119 3120 static DEFINE_PER_CPU(int, perf_throttled_count); 3121 static DEFINE_PER_CPU(u64, perf_throttled_seq); 3122 3123 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable) 3124 { 3125 struct hw_perf_event *hwc = &event->hw; 3126 s64 period, sample_period; 3127 s64 delta; 3128 3129 period = perf_calculate_period(event, nsec, count); 3130 3131 delta = (s64)(period - hwc->sample_period); 3132 delta = (delta + 7) / 8; /* low pass filter */ 3133 3134 sample_period = hwc->sample_period + delta; 3135 3136 if (!sample_period) 3137 sample_period = 1; 3138 3139 hwc->sample_period = sample_period; 3140 3141 if (local64_read(&hwc->period_left) > 8*sample_period) { 3142 if (disable) 3143 event->pmu->stop(event, PERF_EF_UPDATE); 3144 3145 local64_set(&hwc->period_left, 0); 3146 3147 if (disable) 3148 event->pmu->start(event, PERF_EF_RELOAD); 3149 } 3150 } 3151 3152 /* 3153 * combine freq adjustment with unthrottling to avoid two passes over the 3154 * events. At the same time, make sure, having freq events does not change 3155 * the rate of unthrottling as that would introduce bias. 3156 */ 3157 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx, 3158 int needs_unthr) 3159 { 3160 struct perf_event *event; 3161 struct hw_perf_event *hwc; 3162 u64 now, period = TICK_NSEC; 3163 s64 delta; 3164 3165 /* 3166 * only need to iterate over all events iff: 3167 * - context have events in frequency mode (needs freq adjust) 3168 * - there are events to unthrottle on this cpu 3169 */ 3170 if (!(ctx->nr_freq || needs_unthr)) 3171 return; 3172 3173 raw_spin_lock(&ctx->lock); 3174 perf_pmu_disable(ctx->pmu); 3175 3176 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 3177 if (event->state != PERF_EVENT_STATE_ACTIVE) 3178 continue; 3179 3180 if (!event_filter_match(event)) 3181 continue; 3182 3183 perf_pmu_disable(event->pmu); 3184 3185 hwc = &event->hw; 3186 3187 if (hwc->interrupts == MAX_INTERRUPTS) { 3188 hwc->interrupts = 0; 3189 perf_log_throttle(event, 1); 3190 event->pmu->start(event, 0); 3191 } 3192 3193 if (!event->attr.freq || !event->attr.sample_freq) 3194 goto next; 3195 3196 /* 3197 * stop the event and update event->count 3198 */ 3199 event->pmu->stop(event, PERF_EF_UPDATE); 3200 3201 now = local64_read(&event->count); 3202 delta = now - hwc->freq_count_stamp; 3203 hwc->freq_count_stamp = now; 3204 3205 /* 3206 * restart the event 3207 * reload only if value has changed 3208 * we have stopped the event so tell that 3209 * to perf_adjust_period() to avoid stopping it 3210 * twice. 3211 */ 3212 if (delta > 0) 3213 perf_adjust_period(event, period, delta, false); 3214 3215 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0); 3216 next: 3217 perf_pmu_enable(event->pmu); 3218 } 3219 3220 perf_pmu_enable(ctx->pmu); 3221 raw_spin_unlock(&ctx->lock); 3222 } 3223 3224 /* 3225 * Round-robin a context's events: 3226 */ 3227 static void rotate_ctx(struct perf_event_context *ctx) 3228 { 3229 /* 3230 * Rotate the first entry last of non-pinned groups. Rotation might be 3231 * disabled by the inheritance code. 3232 */ 3233 if (!ctx->rotate_disable) 3234 list_rotate_left(&ctx->flexible_groups); 3235 } 3236 3237 static int perf_rotate_context(struct perf_cpu_context *cpuctx) 3238 { 3239 struct perf_event_context *ctx = NULL; 3240 int rotate = 0; 3241 3242 if (cpuctx->ctx.nr_events) { 3243 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active) 3244 rotate = 1; 3245 } 3246 3247 ctx = cpuctx->task_ctx; 3248 if (ctx && ctx->nr_events) { 3249 if (ctx->nr_events != ctx->nr_active) 3250 rotate = 1; 3251 } 3252 3253 if (!rotate) 3254 goto done; 3255 3256 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 3257 perf_pmu_disable(cpuctx->ctx.pmu); 3258 3259 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); 3260 if (ctx) 3261 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE); 3262 3263 rotate_ctx(&cpuctx->ctx); 3264 if (ctx) 3265 rotate_ctx(ctx); 3266 3267 perf_event_sched_in(cpuctx, ctx, current); 3268 3269 perf_pmu_enable(cpuctx->ctx.pmu); 3270 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 3271 done: 3272 3273 return rotate; 3274 } 3275 3276 void perf_event_task_tick(void) 3277 { 3278 struct list_head *head = this_cpu_ptr(&active_ctx_list); 3279 struct perf_event_context *ctx, *tmp; 3280 int throttled; 3281 3282 WARN_ON(!irqs_disabled()); 3283 3284 __this_cpu_inc(perf_throttled_seq); 3285 throttled = __this_cpu_xchg(perf_throttled_count, 0); 3286 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); 3287 3288 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list) 3289 perf_adjust_freq_unthr_context(ctx, throttled); 3290 } 3291 3292 static int event_enable_on_exec(struct perf_event *event, 3293 struct perf_event_context *ctx) 3294 { 3295 if (!event->attr.enable_on_exec) 3296 return 0; 3297 3298 event->attr.enable_on_exec = 0; 3299 if (event->state >= PERF_EVENT_STATE_INACTIVE) 3300 return 0; 3301 3302 __perf_event_mark_enabled(event); 3303 3304 return 1; 3305 } 3306 3307 /* 3308 * Enable all of a task's events that have been marked enable-on-exec. 3309 * This expects task == current. 3310 */ 3311 static void perf_event_enable_on_exec(int ctxn) 3312 { 3313 struct perf_event_context *ctx, *clone_ctx = NULL; 3314 struct perf_cpu_context *cpuctx; 3315 struct perf_event *event; 3316 unsigned long flags; 3317 int enabled = 0; 3318 3319 local_irq_save(flags); 3320 ctx = current->perf_event_ctxp[ctxn]; 3321 if (!ctx || !ctx->nr_events) 3322 goto out; 3323 3324 cpuctx = __get_cpu_context(ctx); 3325 perf_ctx_lock(cpuctx, ctx); 3326 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 3327 list_for_each_entry(event, &ctx->event_list, event_entry) 3328 enabled |= event_enable_on_exec(event, ctx); 3329 3330 /* 3331 * Unclone and reschedule this context if we enabled any event. 3332 */ 3333 if (enabled) { 3334 clone_ctx = unclone_ctx(ctx); 3335 ctx_resched(cpuctx, ctx); 3336 } 3337 perf_ctx_unlock(cpuctx, ctx); 3338 3339 out: 3340 local_irq_restore(flags); 3341 3342 if (clone_ctx) 3343 put_ctx(clone_ctx); 3344 } 3345 3346 struct perf_read_data { 3347 struct perf_event *event; 3348 bool group; 3349 int ret; 3350 }; 3351 3352 /* 3353 * Cross CPU call to read the hardware event 3354 */ 3355 static void __perf_event_read(void *info) 3356 { 3357 struct perf_read_data *data = info; 3358 struct perf_event *sub, *event = data->event; 3359 struct perf_event_context *ctx = event->ctx; 3360 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 3361 struct pmu *pmu = event->pmu; 3362 3363 /* 3364 * If this is a task context, we need to check whether it is 3365 * the current task context of this cpu. If not it has been 3366 * scheduled out before the smp call arrived. In that case 3367 * event->count would have been updated to a recent sample 3368 * when the event was scheduled out. 3369 */ 3370 if (ctx->task && cpuctx->task_ctx != ctx) 3371 return; 3372 3373 raw_spin_lock(&ctx->lock); 3374 if (ctx->is_active) { 3375 update_context_time(ctx); 3376 update_cgrp_time_from_event(event); 3377 } 3378 3379 update_event_times(event); 3380 if (event->state != PERF_EVENT_STATE_ACTIVE) 3381 goto unlock; 3382 3383 if (!data->group) { 3384 pmu->read(event); 3385 data->ret = 0; 3386 goto unlock; 3387 } 3388 3389 pmu->start_txn(pmu, PERF_PMU_TXN_READ); 3390 3391 pmu->read(event); 3392 3393 list_for_each_entry(sub, &event->sibling_list, group_entry) { 3394 update_event_times(sub); 3395 if (sub->state == PERF_EVENT_STATE_ACTIVE) { 3396 /* 3397 * Use sibling's PMU rather than @event's since 3398 * sibling could be on different (eg: software) PMU. 3399 */ 3400 sub->pmu->read(sub); 3401 } 3402 } 3403 3404 data->ret = pmu->commit_txn(pmu); 3405 3406 unlock: 3407 raw_spin_unlock(&ctx->lock); 3408 } 3409 3410 static inline u64 perf_event_count(struct perf_event *event) 3411 { 3412 if (event->pmu->count) 3413 return event->pmu->count(event); 3414 3415 return __perf_event_count(event); 3416 } 3417 3418 /* 3419 * NMI-safe method to read a local event, that is an event that 3420 * is: 3421 * - either for the current task, or for this CPU 3422 * - does not have inherit set, for inherited task events 3423 * will not be local and we cannot read them atomically 3424 * - must not have a pmu::count method 3425 */ 3426 u64 perf_event_read_local(struct perf_event *event) 3427 { 3428 unsigned long flags; 3429 u64 val; 3430 3431 /* 3432 * Disabling interrupts avoids all counter scheduling (context 3433 * switches, timer based rotation and IPIs). 3434 */ 3435 local_irq_save(flags); 3436 3437 /* If this is a per-task event, it must be for current */ 3438 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) && 3439 event->hw.target != current); 3440 3441 /* If this is a per-CPU event, it must be for this CPU */ 3442 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) && 3443 event->cpu != smp_processor_id()); 3444 3445 /* 3446 * It must not be an event with inherit set, we cannot read 3447 * all child counters from atomic context. 3448 */ 3449 WARN_ON_ONCE(event->attr.inherit); 3450 3451 /* 3452 * It must not have a pmu::count method, those are not 3453 * NMI safe. 3454 */ 3455 WARN_ON_ONCE(event->pmu->count); 3456 3457 /* 3458 * If the event is currently on this CPU, its either a per-task event, 3459 * or local to this CPU. Furthermore it means its ACTIVE (otherwise 3460 * oncpu == -1). 3461 */ 3462 if (event->oncpu == smp_processor_id()) 3463 event->pmu->read(event); 3464 3465 val = local64_read(&event->count); 3466 local_irq_restore(flags); 3467 3468 return val; 3469 } 3470 3471 static int perf_event_read(struct perf_event *event, bool group) 3472 { 3473 int ret = 0; 3474 3475 /* 3476 * If event is enabled and currently active on a CPU, update the 3477 * value in the event structure: 3478 */ 3479 if (event->state == PERF_EVENT_STATE_ACTIVE) { 3480 struct perf_read_data data = { 3481 .event = event, 3482 .group = group, 3483 .ret = 0, 3484 }; 3485 smp_call_function_single(event->oncpu, 3486 __perf_event_read, &data, 1); 3487 ret = data.ret; 3488 } else if (event->state == PERF_EVENT_STATE_INACTIVE) { 3489 struct perf_event_context *ctx = event->ctx; 3490 unsigned long flags; 3491 3492 raw_spin_lock_irqsave(&ctx->lock, flags); 3493 /* 3494 * may read while context is not active 3495 * (e.g., thread is blocked), in that case 3496 * we cannot update context time 3497 */ 3498 if (ctx->is_active) { 3499 update_context_time(ctx); 3500 update_cgrp_time_from_event(event); 3501 } 3502 if (group) 3503 update_group_times(event); 3504 else 3505 update_event_times(event); 3506 raw_spin_unlock_irqrestore(&ctx->lock, flags); 3507 } 3508 3509 return ret; 3510 } 3511 3512 /* 3513 * Initialize the perf_event context in a task_struct: 3514 */ 3515 static void __perf_event_init_context(struct perf_event_context *ctx) 3516 { 3517 raw_spin_lock_init(&ctx->lock); 3518 mutex_init(&ctx->mutex); 3519 INIT_LIST_HEAD(&ctx->active_ctx_list); 3520 INIT_LIST_HEAD(&ctx->pinned_groups); 3521 INIT_LIST_HEAD(&ctx->flexible_groups); 3522 INIT_LIST_HEAD(&ctx->event_list); 3523 atomic_set(&ctx->refcount, 1); 3524 } 3525 3526 static struct perf_event_context * 3527 alloc_perf_context(struct pmu *pmu, struct task_struct *task) 3528 { 3529 struct perf_event_context *ctx; 3530 3531 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL); 3532 if (!ctx) 3533 return NULL; 3534 3535 __perf_event_init_context(ctx); 3536 if (task) { 3537 ctx->task = task; 3538 get_task_struct(task); 3539 } 3540 ctx->pmu = pmu; 3541 3542 return ctx; 3543 } 3544 3545 static struct task_struct * 3546 find_lively_task_by_vpid(pid_t vpid) 3547 { 3548 struct task_struct *task; 3549 3550 rcu_read_lock(); 3551 if (!vpid) 3552 task = current; 3553 else 3554 task = find_task_by_vpid(vpid); 3555 if (task) 3556 get_task_struct(task); 3557 rcu_read_unlock(); 3558 3559 if (!task) 3560 return ERR_PTR(-ESRCH); 3561 3562 return task; 3563 } 3564 3565 /* 3566 * Returns a matching context with refcount and pincount. 3567 */ 3568 static struct perf_event_context * 3569 find_get_context(struct pmu *pmu, struct task_struct *task, 3570 struct perf_event *event) 3571 { 3572 struct perf_event_context *ctx, *clone_ctx = NULL; 3573 struct perf_cpu_context *cpuctx; 3574 void *task_ctx_data = NULL; 3575 unsigned long flags; 3576 int ctxn, err; 3577 int cpu = event->cpu; 3578 3579 if (!task) { 3580 /* Must be root to operate on a CPU event: */ 3581 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN)) 3582 return ERR_PTR(-EACCES); 3583 3584 /* 3585 * We could be clever and allow to attach a event to an 3586 * offline CPU and activate it when the CPU comes up, but 3587 * that's for later. 3588 */ 3589 if (!cpu_online(cpu)) 3590 return ERR_PTR(-ENODEV); 3591 3592 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 3593 ctx = &cpuctx->ctx; 3594 get_ctx(ctx); 3595 ++ctx->pin_count; 3596 3597 return ctx; 3598 } 3599 3600 err = -EINVAL; 3601 ctxn = pmu->task_ctx_nr; 3602 if (ctxn < 0) 3603 goto errout; 3604 3605 if (event->attach_state & PERF_ATTACH_TASK_DATA) { 3606 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL); 3607 if (!task_ctx_data) { 3608 err = -ENOMEM; 3609 goto errout; 3610 } 3611 } 3612 3613 retry: 3614 ctx = perf_lock_task_context(task, ctxn, &flags); 3615 if (ctx) { 3616 clone_ctx = unclone_ctx(ctx); 3617 ++ctx->pin_count; 3618 3619 if (task_ctx_data && !ctx->task_ctx_data) { 3620 ctx->task_ctx_data = task_ctx_data; 3621 task_ctx_data = NULL; 3622 } 3623 raw_spin_unlock_irqrestore(&ctx->lock, flags); 3624 3625 if (clone_ctx) 3626 put_ctx(clone_ctx); 3627 } else { 3628 ctx = alloc_perf_context(pmu, task); 3629 err = -ENOMEM; 3630 if (!ctx) 3631 goto errout; 3632 3633 if (task_ctx_data) { 3634 ctx->task_ctx_data = task_ctx_data; 3635 task_ctx_data = NULL; 3636 } 3637 3638 err = 0; 3639 mutex_lock(&task->perf_event_mutex); 3640 /* 3641 * If it has already passed perf_event_exit_task(). 3642 * we must see PF_EXITING, it takes this mutex too. 3643 */ 3644 if (task->flags & PF_EXITING) 3645 err = -ESRCH; 3646 else if (task->perf_event_ctxp[ctxn]) 3647 err = -EAGAIN; 3648 else { 3649 get_ctx(ctx); 3650 ++ctx->pin_count; 3651 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx); 3652 } 3653 mutex_unlock(&task->perf_event_mutex); 3654 3655 if (unlikely(err)) { 3656 put_ctx(ctx); 3657 3658 if (err == -EAGAIN) 3659 goto retry; 3660 goto errout; 3661 } 3662 } 3663 3664 kfree(task_ctx_data); 3665 return ctx; 3666 3667 errout: 3668 kfree(task_ctx_data); 3669 return ERR_PTR(err); 3670 } 3671 3672 static void perf_event_free_filter(struct perf_event *event); 3673 static void perf_event_free_bpf_prog(struct perf_event *event); 3674 3675 static void free_event_rcu(struct rcu_head *head) 3676 { 3677 struct perf_event *event; 3678 3679 event = container_of(head, struct perf_event, rcu_head); 3680 if (event->ns) 3681 put_pid_ns(event->ns); 3682 perf_event_free_filter(event); 3683 kfree(event); 3684 } 3685 3686 static void ring_buffer_attach(struct perf_event *event, 3687 struct ring_buffer *rb); 3688 3689 static void unaccount_event_cpu(struct perf_event *event, int cpu) 3690 { 3691 if (event->parent) 3692 return; 3693 3694 if (is_cgroup_event(event)) 3695 atomic_dec(&per_cpu(perf_cgroup_events, cpu)); 3696 } 3697 3698 #ifdef CONFIG_NO_HZ_FULL 3699 static DEFINE_SPINLOCK(nr_freq_lock); 3700 #endif 3701 3702 static void unaccount_freq_event_nohz(void) 3703 { 3704 #ifdef CONFIG_NO_HZ_FULL 3705 spin_lock(&nr_freq_lock); 3706 if (atomic_dec_and_test(&nr_freq_events)) 3707 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS); 3708 spin_unlock(&nr_freq_lock); 3709 #endif 3710 } 3711 3712 static void unaccount_freq_event(void) 3713 { 3714 if (tick_nohz_full_enabled()) 3715 unaccount_freq_event_nohz(); 3716 else 3717 atomic_dec(&nr_freq_events); 3718 } 3719 3720 static void unaccount_event(struct perf_event *event) 3721 { 3722 bool dec = false; 3723 3724 if (event->parent) 3725 return; 3726 3727 if (event->attach_state & PERF_ATTACH_TASK) 3728 dec = true; 3729 if (event->attr.mmap || event->attr.mmap_data) 3730 atomic_dec(&nr_mmap_events); 3731 if (event->attr.comm) 3732 atomic_dec(&nr_comm_events); 3733 if (event->attr.task) 3734 atomic_dec(&nr_task_events); 3735 if (event->attr.freq) 3736 unaccount_freq_event(); 3737 if (event->attr.context_switch) { 3738 dec = true; 3739 atomic_dec(&nr_switch_events); 3740 } 3741 if (is_cgroup_event(event)) 3742 dec = true; 3743 if (has_branch_stack(event)) 3744 dec = true; 3745 3746 if (dec) { 3747 if (!atomic_add_unless(&perf_sched_count, -1, 1)) 3748 schedule_delayed_work(&perf_sched_work, HZ); 3749 } 3750 3751 unaccount_event_cpu(event, event->cpu); 3752 } 3753 3754 static void perf_sched_delayed(struct work_struct *work) 3755 { 3756 mutex_lock(&perf_sched_mutex); 3757 if (atomic_dec_and_test(&perf_sched_count)) 3758 static_branch_disable(&perf_sched_events); 3759 mutex_unlock(&perf_sched_mutex); 3760 } 3761 3762 /* 3763 * The following implement mutual exclusion of events on "exclusive" pmus 3764 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled 3765 * at a time, so we disallow creating events that might conflict, namely: 3766 * 3767 * 1) cpu-wide events in the presence of per-task events, 3768 * 2) per-task events in the presence of cpu-wide events, 3769 * 3) two matching events on the same context. 3770 * 3771 * The former two cases are handled in the allocation path (perf_event_alloc(), 3772 * _free_event()), the latter -- before the first perf_install_in_context(). 3773 */ 3774 static int exclusive_event_init(struct perf_event *event) 3775 { 3776 struct pmu *pmu = event->pmu; 3777 3778 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE)) 3779 return 0; 3780 3781 /* 3782 * Prevent co-existence of per-task and cpu-wide events on the 3783 * same exclusive pmu. 3784 * 3785 * Negative pmu::exclusive_cnt means there are cpu-wide 3786 * events on this "exclusive" pmu, positive means there are 3787 * per-task events. 3788 * 3789 * Since this is called in perf_event_alloc() path, event::ctx 3790 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK 3791 * to mean "per-task event", because unlike other attach states it 3792 * never gets cleared. 3793 */ 3794 if (event->attach_state & PERF_ATTACH_TASK) { 3795 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt)) 3796 return -EBUSY; 3797 } else { 3798 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt)) 3799 return -EBUSY; 3800 } 3801 3802 return 0; 3803 } 3804 3805 static void exclusive_event_destroy(struct perf_event *event) 3806 { 3807 struct pmu *pmu = event->pmu; 3808 3809 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE)) 3810 return; 3811 3812 /* see comment in exclusive_event_init() */ 3813 if (event->attach_state & PERF_ATTACH_TASK) 3814 atomic_dec(&pmu->exclusive_cnt); 3815 else 3816 atomic_inc(&pmu->exclusive_cnt); 3817 } 3818 3819 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2) 3820 { 3821 if ((e1->pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && 3822 (e1->cpu == e2->cpu || 3823 e1->cpu == -1 || 3824 e2->cpu == -1)) 3825 return true; 3826 return false; 3827 } 3828 3829 /* Called under the same ctx::mutex as perf_install_in_context() */ 3830 static bool exclusive_event_installable(struct perf_event *event, 3831 struct perf_event_context *ctx) 3832 { 3833 struct perf_event *iter_event; 3834 struct pmu *pmu = event->pmu; 3835 3836 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE)) 3837 return true; 3838 3839 list_for_each_entry(iter_event, &ctx->event_list, event_entry) { 3840 if (exclusive_event_match(iter_event, event)) 3841 return false; 3842 } 3843 3844 return true; 3845 } 3846 3847 static void perf_addr_filters_splice(struct perf_event *event, 3848 struct list_head *head); 3849 3850 static void _free_event(struct perf_event *event) 3851 { 3852 irq_work_sync(&event->pending); 3853 3854 unaccount_event(event); 3855 3856 if (event->rb) { 3857 /* 3858 * Can happen when we close an event with re-directed output. 3859 * 3860 * Since we have a 0 refcount, perf_mmap_close() will skip 3861 * over us; possibly making our ring_buffer_put() the last. 3862 */ 3863 mutex_lock(&event->mmap_mutex); 3864 ring_buffer_attach(event, NULL); 3865 mutex_unlock(&event->mmap_mutex); 3866 } 3867 3868 if (is_cgroup_event(event)) 3869 perf_detach_cgroup(event); 3870 3871 if (!event->parent) { 3872 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) 3873 put_callchain_buffers(); 3874 } 3875 3876 perf_event_free_bpf_prog(event); 3877 perf_addr_filters_splice(event, NULL); 3878 kfree(event->addr_filters_offs); 3879 3880 if (event->destroy) 3881 event->destroy(event); 3882 3883 if (event->ctx) 3884 put_ctx(event->ctx); 3885 3886 exclusive_event_destroy(event); 3887 module_put(event->pmu->module); 3888 3889 call_rcu(&event->rcu_head, free_event_rcu); 3890 } 3891 3892 /* 3893 * Used to free events which have a known refcount of 1, such as in error paths 3894 * where the event isn't exposed yet and inherited events. 3895 */ 3896 static void free_event(struct perf_event *event) 3897 { 3898 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1, 3899 "unexpected event refcount: %ld; ptr=%p\n", 3900 atomic_long_read(&event->refcount), event)) { 3901 /* leak to avoid use-after-free */ 3902 return; 3903 } 3904 3905 _free_event(event); 3906 } 3907 3908 /* 3909 * Remove user event from the owner task. 3910 */ 3911 static void perf_remove_from_owner(struct perf_event *event) 3912 { 3913 struct task_struct *owner; 3914 3915 rcu_read_lock(); 3916 /* 3917 * Matches the smp_store_release() in perf_event_exit_task(). If we 3918 * observe !owner it means the list deletion is complete and we can 3919 * indeed free this event, otherwise we need to serialize on 3920 * owner->perf_event_mutex. 3921 */ 3922 owner = lockless_dereference(event->owner); 3923 if (owner) { 3924 /* 3925 * Since delayed_put_task_struct() also drops the last 3926 * task reference we can safely take a new reference 3927 * while holding the rcu_read_lock(). 3928 */ 3929 get_task_struct(owner); 3930 } 3931 rcu_read_unlock(); 3932 3933 if (owner) { 3934 /* 3935 * If we're here through perf_event_exit_task() we're already 3936 * holding ctx->mutex which would be an inversion wrt. the 3937 * normal lock order. 3938 * 3939 * However we can safely take this lock because its the child 3940 * ctx->mutex. 3941 */ 3942 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING); 3943 3944 /* 3945 * We have to re-check the event->owner field, if it is cleared 3946 * we raced with perf_event_exit_task(), acquiring the mutex 3947 * ensured they're done, and we can proceed with freeing the 3948 * event. 3949 */ 3950 if (event->owner) { 3951 list_del_init(&event->owner_entry); 3952 smp_store_release(&event->owner, NULL); 3953 } 3954 mutex_unlock(&owner->perf_event_mutex); 3955 put_task_struct(owner); 3956 } 3957 } 3958 3959 static void put_event(struct perf_event *event) 3960 { 3961 if (!atomic_long_dec_and_test(&event->refcount)) 3962 return; 3963 3964 _free_event(event); 3965 } 3966 3967 /* 3968 * Kill an event dead; while event:refcount will preserve the event 3969 * object, it will not preserve its functionality. Once the last 'user' 3970 * gives up the object, we'll destroy the thing. 3971 */ 3972 int perf_event_release_kernel(struct perf_event *event) 3973 { 3974 struct perf_event_context *ctx = event->ctx; 3975 struct perf_event *child, *tmp; 3976 3977 /* 3978 * If we got here through err_file: fput(event_file); we will not have 3979 * attached to a context yet. 3980 */ 3981 if (!ctx) { 3982 WARN_ON_ONCE(event->attach_state & 3983 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP)); 3984 goto no_ctx; 3985 } 3986 3987 if (!is_kernel_event(event)) 3988 perf_remove_from_owner(event); 3989 3990 ctx = perf_event_ctx_lock(event); 3991 WARN_ON_ONCE(ctx->parent_ctx); 3992 perf_remove_from_context(event, DETACH_GROUP); 3993 3994 raw_spin_lock_irq(&ctx->lock); 3995 /* 3996 * Mark this even as STATE_DEAD, there is no external reference to it 3997 * anymore. 3998 * 3999 * Anybody acquiring event->child_mutex after the below loop _must_ 4000 * also see this, most importantly inherit_event() which will avoid 4001 * placing more children on the list. 4002 * 4003 * Thus this guarantees that we will in fact observe and kill _ALL_ 4004 * child events. 4005 */ 4006 event->state = PERF_EVENT_STATE_DEAD; 4007 raw_spin_unlock_irq(&ctx->lock); 4008 4009 perf_event_ctx_unlock(event, ctx); 4010 4011 again: 4012 mutex_lock(&event->child_mutex); 4013 list_for_each_entry(child, &event->child_list, child_list) { 4014 4015 /* 4016 * Cannot change, child events are not migrated, see the 4017 * comment with perf_event_ctx_lock_nested(). 4018 */ 4019 ctx = lockless_dereference(child->ctx); 4020 /* 4021 * Since child_mutex nests inside ctx::mutex, we must jump 4022 * through hoops. We start by grabbing a reference on the ctx. 4023 * 4024 * Since the event cannot get freed while we hold the 4025 * child_mutex, the context must also exist and have a !0 4026 * reference count. 4027 */ 4028 get_ctx(ctx); 4029 4030 /* 4031 * Now that we have a ctx ref, we can drop child_mutex, and 4032 * acquire ctx::mutex without fear of it going away. Then we 4033 * can re-acquire child_mutex. 4034 */ 4035 mutex_unlock(&event->child_mutex); 4036 mutex_lock(&ctx->mutex); 4037 mutex_lock(&event->child_mutex); 4038 4039 /* 4040 * Now that we hold ctx::mutex and child_mutex, revalidate our 4041 * state, if child is still the first entry, it didn't get freed 4042 * and we can continue doing so. 4043 */ 4044 tmp = list_first_entry_or_null(&event->child_list, 4045 struct perf_event, child_list); 4046 if (tmp == child) { 4047 perf_remove_from_context(child, DETACH_GROUP); 4048 list_del(&child->child_list); 4049 free_event(child); 4050 /* 4051 * This matches the refcount bump in inherit_event(); 4052 * this can't be the last reference. 4053 */ 4054 put_event(event); 4055 } 4056 4057 mutex_unlock(&event->child_mutex); 4058 mutex_unlock(&ctx->mutex); 4059 put_ctx(ctx); 4060 goto again; 4061 } 4062 mutex_unlock(&event->child_mutex); 4063 4064 no_ctx: 4065 put_event(event); /* Must be the 'last' reference */ 4066 return 0; 4067 } 4068 EXPORT_SYMBOL_GPL(perf_event_release_kernel); 4069 4070 /* 4071 * Called when the last reference to the file is gone. 4072 */ 4073 static int perf_release(struct inode *inode, struct file *file) 4074 { 4075 perf_event_release_kernel(file->private_data); 4076 return 0; 4077 } 4078 4079 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) 4080 { 4081 struct perf_event *child; 4082 u64 total = 0; 4083 4084 *enabled = 0; 4085 *running = 0; 4086 4087 mutex_lock(&event->child_mutex); 4088 4089 (void)perf_event_read(event, false); 4090 total += perf_event_count(event); 4091 4092 *enabled += event->total_time_enabled + 4093 atomic64_read(&event->child_total_time_enabled); 4094 *running += event->total_time_running + 4095 atomic64_read(&event->child_total_time_running); 4096 4097 list_for_each_entry(child, &event->child_list, child_list) { 4098 (void)perf_event_read(child, false); 4099 total += perf_event_count(child); 4100 *enabled += child->total_time_enabled; 4101 *running += child->total_time_running; 4102 } 4103 mutex_unlock(&event->child_mutex); 4104 4105 return total; 4106 } 4107 EXPORT_SYMBOL_GPL(perf_event_read_value); 4108 4109 static int __perf_read_group_add(struct perf_event *leader, 4110 u64 read_format, u64 *values) 4111 { 4112 struct perf_event *sub; 4113 int n = 1; /* skip @nr */ 4114 int ret; 4115 4116 ret = perf_event_read(leader, true); 4117 if (ret) 4118 return ret; 4119 4120 /* 4121 * Since we co-schedule groups, {enabled,running} times of siblings 4122 * will be identical to those of the leader, so we only publish one 4123 * set. 4124 */ 4125 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { 4126 values[n++] += leader->total_time_enabled + 4127 atomic64_read(&leader->child_total_time_enabled); 4128 } 4129 4130 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { 4131 values[n++] += leader->total_time_running + 4132 atomic64_read(&leader->child_total_time_running); 4133 } 4134 4135 /* 4136 * Write {count,id} tuples for every sibling. 4137 */ 4138 values[n++] += perf_event_count(leader); 4139 if (read_format & PERF_FORMAT_ID) 4140 values[n++] = primary_event_id(leader); 4141 4142 list_for_each_entry(sub, &leader->sibling_list, group_entry) { 4143 values[n++] += perf_event_count(sub); 4144 if (read_format & PERF_FORMAT_ID) 4145 values[n++] = primary_event_id(sub); 4146 } 4147 4148 return 0; 4149 } 4150 4151 static int perf_read_group(struct perf_event *event, 4152 u64 read_format, char __user *buf) 4153 { 4154 struct perf_event *leader = event->group_leader, *child; 4155 struct perf_event_context *ctx = leader->ctx; 4156 int ret; 4157 u64 *values; 4158 4159 lockdep_assert_held(&ctx->mutex); 4160 4161 values = kzalloc(event->read_size, GFP_KERNEL); 4162 if (!values) 4163 return -ENOMEM; 4164 4165 values[0] = 1 + leader->nr_siblings; 4166 4167 /* 4168 * By locking the child_mutex of the leader we effectively 4169 * lock the child list of all siblings.. XXX explain how. 4170 */ 4171 mutex_lock(&leader->child_mutex); 4172 4173 ret = __perf_read_group_add(leader, read_format, values); 4174 if (ret) 4175 goto unlock; 4176 4177 list_for_each_entry(child, &leader->child_list, child_list) { 4178 ret = __perf_read_group_add(child, read_format, values); 4179 if (ret) 4180 goto unlock; 4181 } 4182 4183 mutex_unlock(&leader->child_mutex); 4184 4185 ret = event->read_size; 4186 if (copy_to_user(buf, values, event->read_size)) 4187 ret = -EFAULT; 4188 goto out; 4189 4190 unlock: 4191 mutex_unlock(&leader->child_mutex); 4192 out: 4193 kfree(values); 4194 return ret; 4195 } 4196 4197 static int perf_read_one(struct perf_event *event, 4198 u64 read_format, char __user *buf) 4199 { 4200 u64 enabled, running; 4201 u64 values[4]; 4202 int n = 0; 4203 4204 values[n++] = perf_event_read_value(event, &enabled, &running); 4205 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 4206 values[n++] = enabled; 4207 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 4208 values[n++] = running; 4209 if (read_format & PERF_FORMAT_ID) 4210 values[n++] = primary_event_id(event); 4211 4212 if (copy_to_user(buf, values, n * sizeof(u64))) 4213 return -EFAULT; 4214 4215 return n * sizeof(u64); 4216 } 4217 4218 static bool is_event_hup(struct perf_event *event) 4219 { 4220 bool no_children; 4221 4222 if (event->state > PERF_EVENT_STATE_EXIT) 4223 return false; 4224 4225 mutex_lock(&event->child_mutex); 4226 no_children = list_empty(&event->child_list); 4227 mutex_unlock(&event->child_mutex); 4228 return no_children; 4229 } 4230 4231 /* 4232 * Read the performance event - simple non blocking version for now 4233 */ 4234 static ssize_t 4235 __perf_read(struct perf_event *event, char __user *buf, size_t count) 4236 { 4237 u64 read_format = event->attr.read_format; 4238 int ret; 4239 4240 /* 4241 * Return end-of-file for a read on a event that is in 4242 * error state (i.e. because it was pinned but it couldn't be 4243 * scheduled on to the CPU at some point). 4244 */ 4245 if (event->state == PERF_EVENT_STATE_ERROR) 4246 return 0; 4247 4248 if (count < event->read_size) 4249 return -ENOSPC; 4250 4251 WARN_ON_ONCE(event->ctx->parent_ctx); 4252 if (read_format & PERF_FORMAT_GROUP) 4253 ret = perf_read_group(event, read_format, buf); 4254 else 4255 ret = perf_read_one(event, read_format, buf); 4256 4257 return ret; 4258 } 4259 4260 static ssize_t 4261 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 4262 { 4263 struct perf_event *event = file->private_data; 4264 struct perf_event_context *ctx; 4265 int ret; 4266 4267 ctx = perf_event_ctx_lock(event); 4268 ret = __perf_read(event, buf, count); 4269 perf_event_ctx_unlock(event, ctx); 4270 4271 return ret; 4272 } 4273 4274 static unsigned int perf_poll(struct file *file, poll_table *wait) 4275 { 4276 struct perf_event *event = file->private_data; 4277 struct ring_buffer *rb; 4278 unsigned int events = POLLHUP; 4279 4280 poll_wait(file, &event->waitq, wait); 4281 4282 if (is_event_hup(event)) 4283 return events; 4284 4285 /* 4286 * Pin the event->rb by taking event->mmap_mutex; otherwise 4287 * perf_event_set_output() can swizzle our rb and make us miss wakeups. 4288 */ 4289 mutex_lock(&event->mmap_mutex); 4290 rb = event->rb; 4291 if (rb) 4292 events = atomic_xchg(&rb->poll, 0); 4293 mutex_unlock(&event->mmap_mutex); 4294 return events; 4295 } 4296 4297 static void _perf_event_reset(struct perf_event *event) 4298 { 4299 (void)perf_event_read(event, false); 4300 local64_set(&event->count, 0); 4301 perf_event_update_userpage(event); 4302 } 4303 4304 /* 4305 * Holding the top-level event's child_mutex means that any 4306 * descendant process that has inherited this event will block 4307 * in perf_event_exit_event() if it goes to exit, thus satisfying the 4308 * task existence requirements of perf_event_enable/disable. 4309 */ 4310 static void perf_event_for_each_child(struct perf_event *event, 4311 void (*func)(struct perf_event *)) 4312 { 4313 struct perf_event *child; 4314 4315 WARN_ON_ONCE(event->ctx->parent_ctx); 4316 4317 mutex_lock(&event->child_mutex); 4318 func(event); 4319 list_for_each_entry(child, &event->child_list, child_list) 4320 func(child); 4321 mutex_unlock(&event->child_mutex); 4322 } 4323 4324 static void perf_event_for_each(struct perf_event *event, 4325 void (*func)(struct perf_event *)) 4326 { 4327 struct perf_event_context *ctx = event->ctx; 4328 struct perf_event *sibling; 4329 4330 lockdep_assert_held(&ctx->mutex); 4331 4332 event = event->group_leader; 4333 4334 perf_event_for_each_child(event, func); 4335 list_for_each_entry(sibling, &event->sibling_list, group_entry) 4336 perf_event_for_each_child(sibling, func); 4337 } 4338 4339 static void __perf_event_period(struct perf_event *event, 4340 struct perf_cpu_context *cpuctx, 4341 struct perf_event_context *ctx, 4342 void *info) 4343 { 4344 u64 value = *((u64 *)info); 4345 bool active; 4346 4347 if (event->attr.freq) { 4348 event->attr.sample_freq = value; 4349 } else { 4350 event->attr.sample_period = value; 4351 event->hw.sample_period = value; 4352 } 4353 4354 active = (event->state == PERF_EVENT_STATE_ACTIVE); 4355 if (active) { 4356 perf_pmu_disable(ctx->pmu); 4357 /* 4358 * We could be throttled; unthrottle now to avoid the tick 4359 * trying to unthrottle while we already re-started the event. 4360 */ 4361 if (event->hw.interrupts == MAX_INTERRUPTS) { 4362 event->hw.interrupts = 0; 4363 perf_log_throttle(event, 1); 4364 } 4365 event->pmu->stop(event, PERF_EF_UPDATE); 4366 } 4367 4368 local64_set(&event->hw.period_left, 0); 4369 4370 if (active) { 4371 event->pmu->start(event, PERF_EF_RELOAD); 4372 perf_pmu_enable(ctx->pmu); 4373 } 4374 } 4375 4376 static int perf_event_period(struct perf_event *event, u64 __user *arg) 4377 { 4378 u64 value; 4379 4380 if (!is_sampling_event(event)) 4381 return -EINVAL; 4382 4383 if (copy_from_user(&value, arg, sizeof(value))) 4384 return -EFAULT; 4385 4386 if (!value) 4387 return -EINVAL; 4388 4389 if (event->attr.freq && value > sysctl_perf_event_sample_rate) 4390 return -EINVAL; 4391 4392 event_function_call(event, __perf_event_period, &value); 4393 4394 return 0; 4395 } 4396 4397 static const struct file_operations perf_fops; 4398 4399 static inline int perf_fget_light(int fd, struct fd *p) 4400 { 4401 struct fd f = fdget(fd); 4402 if (!f.file) 4403 return -EBADF; 4404 4405 if (f.file->f_op != &perf_fops) { 4406 fdput(f); 4407 return -EBADF; 4408 } 4409 *p = f; 4410 return 0; 4411 } 4412 4413 static int perf_event_set_output(struct perf_event *event, 4414 struct perf_event *output_event); 4415 static int perf_event_set_filter(struct perf_event *event, void __user *arg); 4416 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd); 4417 4418 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg) 4419 { 4420 void (*func)(struct perf_event *); 4421 u32 flags = arg; 4422 4423 switch (cmd) { 4424 case PERF_EVENT_IOC_ENABLE: 4425 func = _perf_event_enable; 4426 break; 4427 case PERF_EVENT_IOC_DISABLE: 4428 func = _perf_event_disable; 4429 break; 4430 case PERF_EVENT_IOC_RESET: 4431 func = _perf_event_reset; 4432 break; 4433 4434 case PERF_EVENT_IOC_REFRESH: 4435 return _perf_event_refresh(event, arg); 4436 4437 case PERF_EVENT_IOC_PERIOD: 4438 return perf_event_period(event, (u64 __user *)arg); 4439 4440 case PERF_EVENT_IOC_ID: 4441 { 4442 u64 id = primary_event_id(event); 4443 4444 if (copy_to_user((void __user *)arg, &id, sizeof(id))) 4445 return -EFAULT; 4446 return 0; 4447 } 4448 4449 case PERF_EVENT_IOC_SET_OUTPUT: 4450 { 4451 int ret; 4452 if (arg != -1) { 4453 struct perf_event *output_event; 4454 struct fd output; 4455 ret = perf_fget_light(arg, &output); 4456 if (ret) 4457 return ret; 4458 output_event = output.file->private_data; 4459 ret = perf_event_set_output(event, output_event); 4460 fdput(output); 4461 } else { 4462 ret = perf_event_set_output(event, NULL); 4463 } 4464 return ret; 4465 } 4466 4467 case PERF_EVENT_IOC_SET_FILTER: 4468 return perf_event_set_filter(event, (void __user *)arg); 4469 4470 case PERF_EVENT_IOC_SET_BPF: 4471 return perf_event_set_bpf_prog(event, arg); 4472 4473 case PERF_EVENT_IOC_PAUSE_OUTPUT: { 4474 struct ring_buffer *rb; 4475 4476 rcu_read_lock(); 4477 rb = rcu_dereference(event->rb); 4478 if (!rb || !rb->nr_pages) { 4479 rcu_read_unlock(); 4480 return -EINVAL; 4481 } 4482 rb_toggle_paused(rb, !!arg); 4483 rcu_read_unlock(); 4484 return 0; 4485 } 4486 default: 4487 return -ENOTTY; 4488 } 4489 4490 if (flags & PERF_IOC_FLAG_GROUP) 4491 perf_event_for_each(event, func); 4492 else 4493 perf_event_for_each_child(event, func); 4494 4495 return 0; 4496 } 4497 4498 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 4499 { 4500 struct perf_event *event = file->private_data; 4501 struct perf_event_context *ctx; 4502 long ret; 4503 4504 ctx = perf_event_ctx_lock(event); 4505 ret = _perf_ioctl(event, cmd, arg); 4506 perf_event_ctx_unlock(event, ctx); 4507 4508 return ret; 4509 } 4510 4511 #ifdef CONFIG_COMPAT 4512 static long perf_compat_ioctl(struct file *file, unsigned int cmd, 4513 unsigned long arg) 4514 { 4515 switch (_IOC_NR(cmd)) { 4516 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER): 4517 case _IOC_NR(PERF_EVENT_IOC_ID): 4518 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */ 4519 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) { 4520 cmd &= ~IOCSIZE_MASK; 4521 cmd |= sizeof(void *) << IOCSIZE_SHIFT; 4522 } 4523 break; 4524 } 4525 return perf_ioctl(file, cmd, arg); 4526 } 4527 #else 4528 # define perf_compat_ioctl NULL 4529 #endif 4530 4531 int perf_event_task_enable(void) 4532 { 4533 struct perf_event_context *ctx; 4534 struct perf_event *event; 4535 4536 mutex_lock(¤t->perf_event_mutex); 4537 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { 4538 ctx = perf_event_ctx_lock(event); 4539 perf_event_for_each_child(event, _perf_event_enable); 4540 perf_event_ctx_unlock(event, ctx); 4541 } 4542 mutex_unlock(¤t->perf_event_mutex); 4543 4544 return 0; 4545 } 4546 4547 int perf_event_task_disable(void) 4548 { 4549 struct perf_event_context *ctx; 4550 struct perf_event *event; 4551 4552 mutex_lock(¤t->perf_event_mutex); 4553 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { 4554 ctx = perf_event_ctx_lock(event); 4555 perf_event_for_each_child(event, _perf_event_disable); 4556 perf_event_ctx_unlock(event, ctx); 4557 } 4558 mutex_unlock(¤t->perf_event_mutex); 4559 4560 return 0; 4561 } 4562 4563 static int perf_event_index(struct perf_event *event) 4564 { 4565 if (event->hw.state & PERF_HES_STOPPED) 4566 return 0; 4567 4568 if (event->state != PERF_EVENT_STATE_ACTIVE) 4569 return 0; 4570 4571 return event->pmu->event_idx(event); 4572 } 4573 4574 static void calc_timer_values(struct perf_event *event, 4575 u64 *now, 4576 u64 *enabled, 4577 u64 *running) 4578 { 4579 u64 ctx_time; 4580 4581 *now = perf_clock(); 4582 ctx_time = event->shadow_ctx_time + *now; 4583 *enabled = ctx_time - event->tstamp_enabled; 4584 *running = ctx_time - event->tstamp_running; 4585 } 4586 4587 static void perf_event_init_userpage(struct perf_event *event) 4588 { 4589 struct perf_event_mmap_page *userpg; 4590 struct ring_buffer *rb; 4591 4592 rcu_read_lock(); 4593 rb = rcu_dereference(event->rb); 4594 if (!rb) 4595 goto unlock; 4596 4597 userpg = rb->user_page; 4598 4599 /* Allow new userspace to detect that bit 0 is deprecated */ 4600 userpg->cap_bit0_is_deprecated = 1; 4601 userpg->size = offsetof(struct perf_event_mmap_page, __reserved); 4602 userpg->data_offset = PAGE_SIZE; 4603 userpg->data_size = perf_data_size(rb); 4604 4605 unlock: 4606 rcu_read_unlock(); 4607 } 4608 4609 void __weak arch_perf_update_userpage( 4610 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now) 4611 { 4612 } 4613 4614 /* 4615 * Callers need to ensure there can be no nesting of this function, otherwise 4616 * the seqlock logic goes bad. We can not serialize this because the arch 4617 * code calls this from NMI context. 4618 */ 4619 void perf_event_update_userpage(struct perf_event *event) 4620 { 4621 struct perf_event_mmap_page *userpg; 4622 struct ring_buffer *rb; 4623 u64 enabled, running, now; 4624 4625 rcu_read_lock(); 4626 rb = rcu_dereference(event->rb); 4627 if (!rb) 4628 goto unlock; 4629 4630 /* 4631 * compute total_time_enabled, total_time_running 4632 * based on snapshot values taken when the event 4633 * was last scheduled in. 4634 * 4635 * we cannot simply called update_context_time() 4636 * because of locking issue as we can be called in 4637 * NMI context 4638 */ 4639 calc_timer_values(event, &now, &enabled, &running); 4640 4641 userpg = rb->user_page; 4642 /* 4643 * Disable preemption so as to not let the corresponding user-space 4644 * spin too long if we get preempted. 4645 */ 4646 preempt_disable(); 4647 ++userpg->lock; 4648 barrier(); 4649 userpg->index = perf_event_index(event); 4650 userpg->offset = perf_event_count(event); 4651 if (userpg->index) 4652 userpg->offset -= local64_read(&event->hw.prev_count); 4653 4654 userpg->time_enabled = enabled + 4655 atomic64_read(&event->child_total_time_enabled); 4656 4657 userpg->time_running = running + 4658 atomic64_read(&event->child_total_time_running); 4659 4660 arch_perf_update_userpage(event, userpg, now); 4661 4662 barrier(); 4663 ++userpg->lock; 4664 preempt_enable(); 4665 unlock: 4666 rcu_read_unlock(); 4667 } 4668 4669 static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 4670 { 4671 struct perf_event *event = vma->vm_file->private_data; 4672 struct ring_buffer *rb; 4673 int ret = VM_FAULT_SIGBUS; 4674 4675 if (vmf->flags & FAULT_FLAG_MKWRITE) { 4676 if (vmf->pgoff == 0) 4677 ret = 0; 4678 return ret; 4679 } 4680 4681 rcu_read_lock(); 4682 rb = rcu_dereference(event->rb); 4683 if (!rb) 4684 goto unlock; 4685 4686 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE)) 4687 goto unlock; 4688 4689 vmf->page = perf_mmap_to_page(rb, vmf->pgoff); 4690 if (!vmf->page) 4691 goto unlock; 4692 4693 get_page(vmf->page); 4694 vmf->page->mapping = vma->vm_file->f_mapping; 4695 vmf->page->index = vmf->pgoff; 4696 4697 ret = 0; 4698 unlock: 4699 rcu_read_unlock(); 4700 4701 return ret; 4702 } 4703 4704 static void ring_buffer_attach(struct perf_event *event, 4705 struct ring_buffer *rb) 4706 { 4707 struct ring_buffer *old_rb = NULL; 4708 unsigned long flags; 4709 4710 if (event->rb) { 4711 /* 4712 * Should be impossible, we set this when removing 4713 * event->rb_entry and wait/clear when adding event->rb_entry. 4714 */ 4715 WARN_ON_ONCE(event->rcu_pending); 4716 4717 old_rb = event->rb; 4718 spin_lock_irqsave(&old_rb->event_lock, flags); 4719 list_del_rcu(&event->rb_entry); 4720 spin_unlock_irqrestore(&old_rb->event_lock, flags); 4721 4722 event->rcu_batches = get_state_synchronize_rcu(); 4723 event->rcu_pending = 1; 4724 } 4725 4726 if (rb) { 4727 if (event->rcu_pending) { 4728 cond_synchronize_rcu(event->rcu_batches); 4729 event->rcu_pending = 0; 4730 } 4731 4732 spin_lock_irqsave(&rb->event_lock, flags); 4733 list_add_rcu(&event->rb_entry, &rb->event_list); 4734 spin_unlock_irqrestore(&rb->event_lock, flags); 4735 } 4736 4737 rcu_assign_pointer(event->rb, rb); 4738 4739 if (old_rb) { 4740 ring_buffer_put(old_rb); 4741 /* 4742 * Since we detached before setting the new rb, so that we 4743 * could attach the new rb, we could have missed a wakeup. 4744 * Provide it now. 4745 */ 4746 wake_up_all(&event->waitq); 4747 } 4748 } 4749 4750 static void ring_buffer_wakeup(struct perf_event *event) 4751 { 4752 struct ring_buffer *rb; 4753 4754 rcu_read_lock(); 4755 rb = rcu_dereference(event->rb); 4756 if (rb) { 4757 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) 4758 wake_up_all(&event->waitq); 4759 } 4760 rcu_read_unlock(); 4761 } 4762 4763 struct ring_buffer *ring_buffer_get(struct perf_event *event) 4764 { 4765 struct ring_buffer *rb; 4766 4767 rcu_read_lock(); 4768 rb = rcu_dereference(event->rb); 4769 if (rb) { 4770 if (!atomic_inc_not_zero(&rb->refcount)) 4771 rb = NULL; 4772 } 4773 rcu_read_unlock(); 4774 4775 return rb; 4776 } 4777 4778 void ring_buffer_put(struct ring_buffer *rb) 4779 { 4780 if (!atomic_dec_and_test(&rb->refcount)) 4781 return; 4782 4783 WARN_ON_ONCE(!list_empty(&rb->event_list)); 4784 4785 call_rcu(&rb->rcu_head, rb_free_rcu); 4786 } 4787 4788 static void perf_mmap_open(struct vm_area_struct *vma) 4789 { 4790 struct perf_event *event = vma->vm_file->private_data; 4791 4792 atomic_inc(&event->mmap_count); 4793 atomic_inc(&event->rb->mmap_count); 4794 4795 if (vma->vm_pgoff) 4796 atomic_inc(&event->rb->aux_mmap_count); 4797 4798 if (event->pmu->event_mapped) 4799 event->pmu->event_mapped(event); 4800 } 4801 4802 static void perf_pmu_output_stop(struct perf_event *event); 4803 4804 /* 4805 * A buffer can be mmap()ed multiple times; either directly through the same 4806 * event, or through other events by use of perf_event_set_output(). 4807 * 4808 * In order to undo the VM accounting done by perf_mmap() we need to destroy 4809 * the buffer here, where we still have a VM context. This means we need 4810 * to detach all events redirecting to us. 4811 */ 4812 static void perf_mmap_close(struct vm_area_struct *vma) 4813 { 4814 struct perf_event *event = vma->vm_file->private_data; 4815 4816 struct ring_buffer *rb = ring_buffer_get(event); 4817 struct user_struct *mmap_user = rb->mmap_user; 4818 int mmap_locked = rb->mmap_locked; 4819 unsigned long size = perf_data_size(rb); 4820 4821 if (event->pmu->event_unmapped) 4822 event->pmu->event_unmapped(event); 4823 4824 /* 4825 * rb->aux_mmap_count will always drop before rb->mmap_count and 4826 * event->mmap_count, so it is ok to use event->mmap_mutex to 4827 * serialize with perf_mmap here. 4828 */ 4829 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff && 4830 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) { 4831 /* 4832 * Stop all AUX events that are writing to this buffer, 4833 * so that we can free its AUX pages and corresponding PMU 4834 * data. Note that after rb::aux_mmap_count dropped to zero, 4835 * they won't start any more (see perf_aux_output_begin()). 4836 */ 4837 perf_pmu_output_stop(event); 4838 4839 /* now it's safe to free the pages */ 4840 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm); 4841 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked; 4842 4843 /* this has to be the last one */ 4844 rb_free_aux(rb); 4845 WARN_ON_ONCE(atomic_read(&rb->aux_refcount)); 4846 4847 mutex_unlock(&event->mmap_mutex); 4848 } 4849 4850 atomic_dec(&rb->mmap_count); 4851 4852 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) 4853 goto out_put; 4854 4855 ring_buffer_attach(event, NULL); 4856 mutex_unlock(&event->mmap_mutex); 4857 4858 /* If there's still other mmap()s of this buffer, we're done. */ 4859 if (atomic_read(&rb->mmap_count)) 4860 goto out_put; 4861 4862 /* 4863 * No other mmap()s, detach from all other events that might redirect 4864 * into the now unreachable buffer. Somewhat complicated by the 4865 * fact that rb::event_lock otherwise nests inside mmap_mutex. 4866 */ 4867 again: 4868 rcu_read_lock(); 4869 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) { 4870 if (!atomic_long_inc_not_zero(&event->refcount)) { 4871 /* 4872 * This event is en-route to free_event() which will 4873 * detach it and remove it from the list. 4874 */ 4875 continue; 4876 } 4877 rcu_read_unlock(); 4878 4879 mutex_lock(&event->mmap_mutex); 4880 /* 4881 * Check we didn't race with perf_event_set_output() which can 4882 * swizzle the rb from under us while we were waiting to 4883 * acquire mmap_mutex. 4884 * 4885 * If we find a different rb; ignore this event, a next 4886 * iteration will no longer find it on the list. We have to 4887 * still restart the iteration to make sure we're not now 4888 * iterating the wrong list. 4889 */ 4890 if (event->rb == rb) 4891 ring_buffer_attach(event, NULL); 4892 4893 mutex_unlock(&event->mmap_mutex); 4894 put_event(event); 4895 4896 /* 4897 * Restart the iteration; either we're on the wrong list or 4898 * destroyed its integrity by doing a deletion. 4899 */ 4900 goto again; 4901 } 4902 rcu_read_unlock(); 4903 4904 /* 4905 * It could be there's still a few 0-ref events on the list; they'll 4906 * get cleaned up by free_event() -- they'll also still have their 4907 * ref on the rb and will free it whenever they are done with it. 4908 * 4909 * Aside from that, this buffer is 'fully' detached and unmapped, 4910 * undo the VM accounting. 4911 */ 4912 4913 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm); 4914 vma->vm_mm->pinned_vm -= mmap_locked; 4915 free_uid(mmap_user); 4916 4917 out_put: 4918 ring_buffer_put(rb); /* could be last */ 4919 } 4920 4921 static const struct vm_operations_struct perf_mmap_vmops = { 4922 .open = perf_mmap_open, 4923 .close = perf_mmap_close, /* non mergable */ 4924 .fault = perf_mmap_fault, 4925 .page_mkwrite = perf_mmap_fault, 4926 }; 4927 4928 static int perf_mmap(struct file *file, struct vm_area_struct *vma) 4929 { 4930 struct perf_event *event = file->private_data; 4931 unsigned long user_locked, user_lock_limit; 4932 struct user_struct *user = current_user(); 4933 unsigned long locked, lock_limit; 4934 struct ring_buffer *rb = NULL; 4935 unsigned long vma_size; 4936 unsigned long nr_pages; 4937 long user_extra = 0, extra = 0; 4938 int ret = 0, flags = 0; 4939 4940 /* 4941 * Don't allow mmap() of inherited per-task counters. This would 4942 * create a performance issue due to all children writing to the 4943 * same rb. 4944 */ 4945 if (event->cpu == -1 && event->attr.inherit) 4946 return -EINVAL; 4947 4948 if (!(vma->vm_flags & VM_SHARED)) 4949 return -EINVAL; 4950 4951 vma_size = vma->vm_end - vma->vm_start; 4952 4953 if (vma->vm_pgoff == 0) { 4954 nr_pages = (vma_size / PAGE_SIZE) - 1; 4955 } else { 4956 /* 4957 * AUX area mapping: if rb->aux_nr_pages != 0, it's already 4958 * mapped, all subsequent mappings should have the same size 4959 * and offset. Must be above the normal perf buffer. 4960 */ 4961 u64 aux_offset, aux_size; 4962 4963 if (!event->rb) 4964 return -EINVAL; 4965 4966 nr_pages = vma_size / PAGE_SIZE; 4967 4968 mutex_lock(&event->mmap_mutex); 4969 ret = -EINVAL; 4970 4971 rb = event->rb; 4972 if (!rb) 4973 goto aux_unlock; 4974 4975 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset); 4976 aux_size = ACCESS_ONCE(rb->user_page->aux_size); 4977 4978 if (aux_offset < perf_data_size(rb) + PAGE_SIZE) 4979 goto aux_unlock; 4980 4981 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT) 4982 goto aux_unlock; 4983 4984 /* already mapped with a different offset */ 4985 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff) 4986 goto aux_unlock; 4987 4988 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE) 4989 goto aux_unlock; 4990 4991 /* already mapped with a different size */ 4992 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages) 4993 goto aux_unlock; 4994 4995 if (!is_power_of_2(nr_pages)) 4996 goto aux_unlock; 4997 4998 if (!atomic_inc_not_zero(&rb->mmap_count)) 4999 goto aux_unlock; 5000 5001 if (rb_has_aux(rb)) { 5002 atomic_inc(&rb->aux_mmap_count); 5003 ret = 0; 5004 goto unlock; 5005 } 5006 5007 atomic_set(&rb->aux_mmap_count, 1); 5008 user_extra = nr_pages; 5009 5010 goto accounting; 5011 } 5012 5013 /* 5014 * If we have rb pages ensure they're a power-of-two number, so we 5015 * can do bitmasks instead of modulo. 5016 */ 5017 if (nr_pages != 0 && !is_power_of_2(nr_pages)) 5018 return -EINVAL; 5019 5020 if (vma_size != PAGE_SIZE * (1 + nr_pages)) 5021 return -EINVAL; 5022 5023 WARN_ON_ONCE(event->ctx->parent_ctx); 5024 again: 5025 mutex_lock(&event->mmap_mutex); 5026 if (event->rb) { 5027 if (event->rb->nr_pages != nr_pages) { 5028 ret = -EINVAL; 5029 goto unlock; 5030 } 5031 5032 if (!atomic_inc_not_zero(&event->rb->mmap_count)) { 5033 /* 5034 * Raced against perf_mmap_close() through 5035 * perf_event_set_output(). Try again, hope for better 5036 * luck. 5037 */ 5038 mutex_unlock(&event->mmap_mutex); 5039 goto again; 5040 } 5041 5042 goto unlock; 5043 } 5044 5045 user_extra = nr_pages + 1; 5046 5047 accounting: 5048 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10); 5049 5050 /* 5051 * Increase the limit linearly with more CPUs: 5052 */ 5053 user_lock_limit *= num_online_cpus(); 5054 5055 user_locked = atomic_long_read(&user->locked_vm) + user_extra; 5056 5057 if (user_locked > user_lock_limit) 5058 extra = user_locked - user_lock_limit; 5059 5060 lock_limit = rlimit(RLIMIT_MEMLOCK); 5061 lock_limit >>= PAGE_SHIFT; 5062 locked = vma->vm_mm->pinned_vm + extra; 5063 5064 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() && 5065 !capable(CAP_IPC_LOCK)) { 5066 ret = -EPERM; 5067 goto unlock; 5068 } 5069 5070 WARN_ON(!rb && event->rb); 5071 5072 if (vma->vm_flags & VM_WRITE) 5073 flags |= RING_BUFFER_WRITABLE; 5074 5075 if (!rb) { 5076 rb = rb_alloc(nr_pages, 5077 event->attr.watermark ? event->attr.wakeup_watermark : 0, 5078 event->cpu, flags); 5079 5080 if (!rb) { 5081 ret = -ENOMEM; 5082 goto unlock; 5083 } 5084 5085 atomic_set(&rb->mmap_count, 1); 5086 rb->mmap_user = get_current_user(); 5087 rb->mmap_locked = extra; 5088 5089 ring_buffer_attach(event, rb); 5090 5091 perf_event_init_userpage(event); 5092 perf_event_update_userpage(event); 5093 } else { 5094 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages, 5095 event->attr.aux_watermark, flags); 5096 if (!ret) 5097 rb->aux_mmap_locked = extra; 5098 } 5099 5100 unlock: 5101 if (!ret) { 5102 atomic_long_add(user_extra, &user->locked_vm); 5103 vma->vm_mm->pinned_vm += extra; 5104 5105 atomic_inc(&event->mmap_count); 5106 } else if (rb) { 5107 atomic_dec(&rb->mmap_count); 5108 } 5109 aux_unlock: 5110 mutex_unlock(&event->mmap_mutex); 5111 5112 /* 5113 * Since pinned accounting is per vm we cannot allow fork() to copy our 5114 * vma. 5115 */ 5116 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP; 5117 vma->vm_ops = &perf_mmap_vmops; 5118 5119 if (event->pmu->event_mapped) 5120 event->pmu->event_mapped(event); 5121 5122 return ret; 5123 } 5124 5125 static int perf_fasync(int fd, struct file *filp, int on) 5126 { 5127 struct inode *inode = file_inode(filp); 5128 struct perf_event *event = filp->private_data; 5129 int retval; 5130 5131 inode_lock(inode); 5132 retval = fasync_helper(fd, filp, on, &event->fasync); 5133 inode_unlock(inode); 5134 5135 if (retval < 0) 5136 return retval; 5137 5138 return 0; 5139 } 5140 5141 static const struct file_operations perf_fops = { 5142 .llseek = no_llseek, 5143 .release = perf_release, 5144 .read = perf_read, 5145 .poll = perf_poll, 5146 .unlocked_ioctl = perf_ioctl, 5147 .compat_ioctl = perf_compat_ioctl, 5148 .mmap = perf_mmap, 5149 .fasync = perf_fasync, 5150 }; 5151 5152 /* 5153 * Perf event wakeup 5154 * 5155 * If there's data, ensure we set the poll() state and publish everything 5156 * to user-space before waking everybody up. 5157 */ 5158 5159 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event) 5160 { 5161 /* only the parent has fasync state */ 5162 if (event->parent) 5163 event = event->parent; 5164 return &event->fasync; 5165 } 5166 5167 void perf_event_wakeup(struct perf_event *event) 5168 { 5169 ring_buffer_wakeup(event); 5170 5171 if (event->pending_kill) { 5172 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill); 5173 event->pending_kill = 0; 5174 } 5175 } 5176 5177 static void perf_pending_event(struct irq_work *entry) 5178 { 5179 struct perf_event *event = container_of(entry, 5180 struct perf_event, pending); 5181 int rctx; 5182 5183 rctx = perf_swevent_get_recursion_context(); 5184 /* 5185 * If we 'fail' here, that's OK, it means recursion is already disabled 5186 * and we won't recurse 'further'. 5187 */ 5188 5189 if (event->pending_disable) { 5190 event->pending_disable = 0; 5191 perf_event_disable_local(event); 5192 } 5193 5194 if (event->pending_wakeup) { 5195 event->pending_wakeup = 0; 5196 perf_event_wakeup(event); 5197 } 5198 5199 if (rctx >= 0) 5200 perf_swevent_put_recursion_context(rctx); 5201 } 5202 5203 /* 5204 * We assume there is only KVM supporting the callbacks. 5205 * Later on, we might change it to a list if there is 5206 * another virtualization implementation supporting the callbacks. 5207 */ 5208 struct perf_guest_info_callbacks *perf_guest_cbs; 5209 5210 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) 5211 { 5212 perf_guest_cbs = cbs; 5213 return 0; 5214 } 5215 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks); 5216 5217 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) 5218 { 5219 perf_guest_cbs = NULL; 5220 return 0; 5221 } 5222 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks); 5223 5224 static void 5225 perf_output_sample_regs(struct perf_output_handle *handle, 5226 struct pt_regs *regs, u64 mask) 5227 { 5228 int bit; 5229 5230 for_each_set_bit(bit, (const unsigned long *) &mask, 5231 sizeof(mask) * BITS_PER_BYTE) { 5232 u64 val; 5233 5234 val = perf_reg_value(regs, bit); 5235 perf_output_put(handle, val); 5236 } 5237 } 5238 5239 static void perf_sample_regs_user(struct perf_regs *regs_user, 5240 struct pt_regs *regs, 5241 struct pt_regs *regs_user_copy) 5242 { 5243 if (user_mode(regs)) { 5244 regs_user->abi = perf_reg_abi(current); 5245 regs_user->regs = regs; 5246 } else if (current->mm) { 5247 perf_get_regs_user(regs_user, regs, regs_user_copy); 5248 } else { 5249 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE; 5250 regs_user->regs = NULL; 5251 } 5252 } 5253 5254 static void perf_sample_regs_intr(struct perf_regs *regs_intr, 5255 struct pt_regs *regs) 5256 { 5257 regs_intr->regs = regs; 5258 regs_intr->abi = perf_reg_abi(current); 5259 } 5260 5261 5262 /* 5263 * Get remaining task size from user stack pointer. 5264 * 5265 * It'd be better to take stack vma map and limit this more 5266 * precisly, but there's no way to get it safely under interrupt, 5267 * so using TASK_SIZE as limit. 5268 */ 5269 static u64 perf_ustack_task_size(struct pt_regs *regs) 5270 { 5271 unsigned long addr = perf_user_stack_pointer(regs); 5272 5273 if (!addr || addr >= TASK_SIZE) 5274 return 0; 5275 5276 return TASK_SIZE - addr; 5277 } 5278 5279 static u16 5280 perf_sample_ustack_size(u16 stack_size, u16 header_size, 5281 struct pt_regs *regs) 5282 { 5283 u64 task_size; 5284 5285 /* No regs, no stack pointer, no dump. */ 5286 if (!regs) 5287 return 0; 5288 5289 /* 5290 * Check if we fit in with the requested stack size into the: 5291 * - TASK_SIZE 5292 * If we don't, we limit the size to the TASK_SIZE. 5293 * 5294 * - remaining sample size 5295 * If we don't, we customize the stack size to 5296 * fit in to the remaining sample size. 5297 */ 5298 5299 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs)); 5300 stack_size = min(stack_size, (u16) task_size); 5301 5302 /* Current header size plus static size and dynamic size. */ 5303 header_size += 2 * sizeof(u64); 5304 5305 /* Do we fit in with the current stack dump size? */ 5306 if ((u16) (header_size + stack_size) < header_size) { 5307 /* 5308 * If we overflow the maximum size for the sample, 5309 * we customize the stack dump size to fit in. 5310 */ 5311 stack_size = USHRT_MAX - header_size - sizeof(u64); 5312 stack_size = round_up(stack_size, sizeof(u64)); 5313 } 5314 5315 return stack_size; 5316 } 5317 5318 static void 5319 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size, 5320 struct pt_regs *regs) 5321 { 5322 /* Case of a kernel thread, nothing to dump */ 5323 if (!regs) { 5324 u64 size = 0; 5325 perf_output_put(handle, size); 5326 } else { 5327 unsigned long sp; 5328 unsigned int rem; 5329 u64 dyn_size; 5330 5331 /* 5332 * We dump: 5333 * static size 5334 * - the size requested by user or the best one we can fit 5335 * in to the sample max size 5336 * data 5337 * - user stack dump data 5338 * dynamic size 5339 * - the actual dumped size 5340 */ 5341 5342 /* Static size. */ 5343 perf_output_put(handle, dump_size); 5344 5345 /* Data. */ 5346 sp = perf_user_stack_pointer(regs); 5347 rem = __output_copy_user(handle, (void *) sp, dump_size); 5348 dyn_size = dump_size - rem; 5349 5350 perf_output_skip(handle, rem); 5351 5352 /* Dynamic size. */ 5353 perf_output_put(handle, dyn_size); 5354 } 5355 } 5356 5357 static void __perf_event_header__init_id(struct perf_event_header *header, 5358 struct perf_sample_data *data, 5359 struct perf_event *event) 5360 { 5361 u64 sample_type = event->attr.sample_type; 5362 5363 data->type = sample_type; 5364 header->size += event->id_header_size; 5365 5366 if (sample_type & PERF_SAMPLE_TID) { 5367 /* namespace issues */ 5368 data->tid_entry.pid = perf_event_pid(event, current); 5369 data->tid_entry.tid = perf_event_tid(event, current); 5370 } 5371 5372 if (sample_type & PERF_SAMPLE_TIME) 5373 data->time = perf_event_clock(event); 5374 5375 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER)) 5376 data->id = primary_event_id(event); 5377 5378 if (sample_type & PERF_SAMPLE_STREAM_ID) 5379 data->stream_id = event->id; 5380 5381 if (sample_type & PERF_SAMPLE_CPU) { 5382 data->cpu_entry.cpu = raw_smp_processor_id(); 5383 data->cpu_entry.reserved = 0; 5384 } 5385 } 5386 5387 void perf_event_header__init_id(struct perf_event_header *header, 5388 struct perf_sample_data *data, 5389 struct perf_event *event) 5390 { 5391 if (event->attr.sample_id_all) 5392 __perf_event_header__init_id(header, data, event); 5393 } 5394 5395 static void __perf_event__output_id_sample(struct perf_output_handle *handle, 5396 struct perf_sample_data *data) 5397 { 5398 u64 sample_type = data->type; 5399 5400 if (sample_type & PERF_SAMPLE_TID) 5401 perf_output_put(handle, data->tid_entry); 5402 5403 if (sample_type & PERF_SAMPLE_TIME) 5404 perf_output_put(handle, data->time); 5405 5406 if (sample_type & PERF_SAMPLE_ID) 5407 perf_output_put(handle, data->id); 5408 5409 if (sample_type & PERF_SAMPLE_STREAM_ID) 5410 perf_output_put(handle, data->stream_id); 5411 5412 if (sample_type & PERF_SAMPLE_CPU) 5413 perf_output_put(handle, data->cpu_entry); 5414 5415 if (sample_type & PERF_SAMPLE_IDENTIFIER) 5416 perf_output_put(handle, data->id); 5417 } 5418 5419 void perf_event__output_id_sample(struct perf_event *event, 5420 struct perf_output_handle *handle, 5421 struct perf_sample_data *sample) 5422 { 5423 if (event->attr.sample_id_all) 5424 __perf_event__output_id_sample(handle, sample); 5425 } 5426 5427 static void perf_output_read_one(struct perf_output_handle *handle, 5428 struct perf_event *event, 5429 u64 enabled, u64 running) 5430 { 5431 u64 read_format = event->attr.read_format; 5432 u64 values[4]; 5433 int n = 0; 5434 5435 values[n++] = perf_event_count(event); 5436 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { 5437 values[n++] = enabled + 5438 atomic64_read(&event->child_total_time_enabled); 5439 } 5440 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { 5441 values[n++] = running + 5442 atomic64_read(&event->child_total_time_running); 5443 } 5444 if (read_format & PERF_FORMAT_ID) 5445 values[n++] = primary_event_id(event); 5446 5447 __output_copy(handle, values, n * sizeof(u64)); 5448 } 5449 5450 /* 5451 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult. 5452 */ 5453 static void perf_output_read_group(struct perf_output_handle *handle, 5454 struct perf_event *event, 5455 u64 enabled, u64 running) 5456 { 5457 struct perf_event *leader = event->group_leader, *sub; 5458 u64 read_format = event->attr.read_format; 5459 u64 values[5]; 5460 int n = 0; 5461 5462 values[n++] = 1 + leader->nr_siblings; 5463 5464 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 5465 values[n++] = enabled; 5466 5467 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 5468 values[n++] = running; 5469 5470 if (leader != event) 5471 leader->pmu->read(leader); 5472 5473 values[n++] = perf_event_count(leader); 5474 if (read_format & PERF_FORMAT_ID) 5475 values[n++] = primary_event_id(leader); 5476 5477 __output_copy(handle, values, n * sizeof(u64)); 5478 5479 list_for_each_entry(sub, &leader->sibling_list, group_entry) { 5480 n = 0; 5481 5482 if ((sub != event) && 5483 (sub->state == PERF_EVENT_STATE_ACTIVE)) 5484 sub->pmu->read(sub); 5485 5486 values[n++] = perf_event_count(sub); 5487 if (read_format & PERF_FORMAT_ID) 5488 values[n++] = primary_event_id(sub); 5489 5490 __output_copy(handle, values, n * sizeof(u64)); 5491 } 5492 } 5493 5494 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\ 5495 PERF_FORMAT_TOTAL_TIME_RUNNING) 5496 5497 static void perf_output_read(struct perf_output_handle *handle, 5498 struct perf_event *event) 5499 { 5500 u64 enabled = 0, running = 0, now; 5501 u64 read_format = event->attr.read_format; 5502 5503 /* 5504 * compute total_time_enabled, total_time_running 5505 * based on snapshot values taken when the event 5506 * was last scheduled in. 5507 * 5508 * we cannot simply called update_context_time() 5509 * because of locking issue as we are called in 5510 * NMI context 5511 */ 5512 if (read_format & PERF_FORMAT_TOTAL_TIMES) 5513 calc_timer_values(event, &now, &enabled, &running); 5514 5515 if (event->attr.read_format & PERF_FORMAT_GROUP) 5516 perf_output_read_group(handle, event, enabled, running); 5517 else 5518 perf_output_read_one(handle, event, enabled, running); 5519 } 5520 5521 void perf_output_sample(struct perf_output_handle *handle, 5522 struct perf_event_header *header, 5523 struct perf_sample_data *data, 5524 struct perf_event *event) 5525 { 5526 u64 sample_type = data->type; 5527 5528 perf_output_put(handle, *header); 5529 5530 if (sample_type & PERF_SAMPLE_IDENTIFIER) 5531 perf_output_put(handle, data->id); 5532 5533 if (sample_type & PERF_SAMPLE_IP) 5534 perf_output_put(handle, data->ip); 5535 5536 if (sample_type & PERF_SAMPLE_TID) 5537 perf_output_put(handle, data->tid_entry); 5538 5539 if (sample_type & PERF_SAMPLE_TIME) 5540 perf_output_put(handle, data->time); 5541 5542 if (sample_type & PERF_SAMPLE_ADDR) 5543 perf_output_put(handle, data->addr); 5544 5545 if (sample_type & PERF_SAMPLE_ID) 5546 perf_output_put(handle, data->id); 5547 5548 if (sample_type & PERF_SAMPLE_STREAM_ID) 5549 perf_output_put(handle, data->stream_id); 5550 5551 if (sample_type & PERF_SAMPLE_CPU) 5552 perf_output_put(handle, data->cpu_entry); 5553 5554 if (sample_type & PERF_SAMPLE_PERIOD) 5555 perf_output_put(handle, data->period); 5556 5557 if (sample_type & PERF_SAMPLE_READ) 5558 perf_output_read(handle, event); 5559 5560 if (sample_type & PERF_SAMPLE_CALLCHAIN) { 5561 if (data->callchain) { 5562 int size = 1; 5563 5564 if (data->callchain) 5565 size += data->callchain->nr; 5566 5567 size *= sizeof(u64); 5568 5569 __output_copy(handle, data->callchain, size); 5570 } else { 5571 u64 nr = 0; 5572 perf_output_put(handle, nr); 5573 } 5574 } 5575 5576 if (sample_type & PERF_SAMPLE_RAW) { 5577 if (data->raw) { 5578 u32 raw_size = data->raw->size; 5579 u32 real_size = round_up(raw_size + sizeof(u32), 5580 sizeof(u64)) - sizeof(u32); 5581 u64 zero = 0; 5582 5583 perf_output_put(handle, real_size); 5584 __output_copy(handle, data->raw->data, raw_size); 5585 if (real_size - raw_size) 5586 __output_copy(handle, &zero, real_size - raw_size); 5587 } else { 5588 struct { 5589 u32 size; 5590 u32 data; 5591 } raw = { 5592 .size = sizeof(u32), 5593 .data = 0, 5594 }; 5595 perf_output_put(handle, raw); 5596 } 5597 } 5598 5599 if (sample_type & PERF_SAMPLE_BRANCH_STACK) { 5600 if (data->br_stack) { 5601 size_t size; 5602 5603 size = data->br_stack->nr 5604 * sizeof(struct perf_branch_entry); 5605 5606 perf_output_put(handle, data->br_stack->nr); 5607 perf_output_copy(handle, data->br_stack->entries, size); 5608 } else { 5609 /* 5610 * we always store at least the value of nr 5611 */ 5612 u64 nr = 0; 5613 perf_output_put(handle, nr); 5614 } 5615 } 5616 5617 if (sample_type & PERF_SAMPLE_REGS_USER) { 5618 u64 abi = data->regs_user.abi; 5619 5620 /* 5621 * If there are no regs to dump, notice it through 5622 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). 5623 */ 5624 perf_output_put(handle, abi); 5625 5626 if (abi) { 5627 u64 mask = event->attr.sample_regs_user; 5628 perf_output_sample_regs(handle, 5629 data->regs_user.regs, 5630 mask); 5631 } 5632 } 5633 5634 if (sample_type & PERF_SAMPLE_STACK_USER) { 5635 perf_output_sample_ustack(handle, 5636 data->stack_user_size, 5637 data->regs_user.regs); 5638 } 5639 5640 if (sample_type & PERF_SAMPLE_WEIGHT) 5641 perf_output_put(handle, data->weight); 5642 5643 if (sample_type & PERF_SAMPLE_DATA_SRC) 5644 perf_output_put(handle, data->data_src.val); 5645 5646 if (sample_type & PERF_SAMPLE_TRANSACTION) 5647 perf_output_put(handle, data->txn); 5648 5649 if (sample_type & PERF_SAMPLE_REGS_INTR) { 5650 u64 abi = data->regs_intr.abi; 5651 /* 5652 * If there are no regs to dump, notice it through 5653 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). 5654 */ 5655 perf_output_put(handle, abi); 5656 5657 if (abi) { 5658 u64 mask = event->attr.sample_regs_intr; 5659 5660 perf_output_sample_regs(handle, 5661 data->regs_intr.regs, 5662 mask); 5663 } 5664 } 5665 5666 if (!event->attr.watermark) { 5667 int wakeup_events = event->attr.wakeup_events; 5668 5669 if (wakeup_events) { 5670 struct ring_buffer *rb = handle->rb; 5671 int events = local_inc_return(&rb->events); 5672 5673 if (events >= wakeup_events) { 5674 local_sub(wakeup_events, &rb->events); 5675 local_inc(&rb->wakeup); 5676 } 5677 } 5678 } 5679 } 5680 5681 void perf_prepare_sample(struct perf_event_header *header, 5682 struct perf_sample_data *data, 5683 struct perf_event *event, 5684 struct pt_regs *regs) 5685 { 5686 u64 sample_type = event->attr.sample_type; 5687 5688 header->type = PERF_RECORD_SAMPLE; 5689 header->size = sizeof(*header) + event->header_size; 5690 5691 header->misc = 0; 5692 header->misc |= perf_misc_flags(regs); 5693 5694 __perf_event_header__init_id(header, data, event); 5695 5696 if (sample_type & PERF_SAMPLE_IP) 5697 data->ip = perf_instruction_pointer(regs); 5698 5699 if (sample_type & PERF_SAMPLE_CALLCHAIN) { 5700 int size = 1; 5701 5702 data->callchain = perf_callchain(event, regs); 5703 5704 if (data->callchain) 5705 size += data->callchain->nr; 5706 5707 header->size += size * sizeof(u64); 5708 } 5709 5710 if (sample_type & PERF_SAMPLE_RAW) { 5711 int size = sizeof(u32); 5712 5713 if (data->raw) 5714 size += data->raw->size; 5715 else 5716 size += sizeof(u32); 5717 5718 header->size += round_up(size, sizeof(u64)); 5719 } 5720 5721 if (sample_type & PERF_SAMPLE_BRANCH_STACK) { 5722 int size = sizeof(u64); /* nr */ 5723 if (data->br_stack) { 5724 size += data->br_stack->nr 5725 * sizeof(struct perf_branch_entry); 5726 } 5727 header->size += size; 5728 } 5729 5730 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER)) 5731 perf_sample_regs_user(&data->regs_user, regs, 5732 &data->regs_user_copy); 5733 5734 if (sample_type & PERF_SAMPLE_REGS_USER) { 5735 /* regs dump ABI info */ 5736 int size = sizeof(u64); 5737 5738 if (data->regs_user.regs) { 5739 u64 mask = event->attr.sample_regs_user; 5740 size += hweight64(mask) * sizeof(u64); 5741 } 5742 5743 header->size += size; 5744 } 5745 5746 if (sample_type & PERF_SAMPLE_STACK_USER) { 5747 /* 5748 * Either we need PERF_SAMPLE_STACK_USER bit to be allways 5749 * processed as the last one or have additional check added 5750 * in case new sample type is added, because we could eat 5751 * up the rest of the sample size. 5752 */ 5753 u16 stack_size = event->attr.sample_stack_user; 5754 u16 size = sizeof(u64); 5755 5756 stack_size = perf_sample_ustack_size(stack_size, header->size, 5757 data->regs_user.regs); 5758 5759 /* 5760 * If there is something to dump, add space for the dump 5761 * itself and for the field that tells the dynamic size, 5762 * which is how many have been actually dumped. 5763 */ 5764 if (stack_size) 5765 size += sizeof(u64) + stack_size; 5766 5767 data->stack_user_size = stack_size; 5768 header->size += size; 5769 } 5770 5771 if (sample_type & PERF_SAMPLE_REGS_INTR) { 5772 /* regs dump ABI info */ 5773 int size = sizeof(u64); 5774 5775 perf_sample_regs_intr(&data->regs_intr, regs); 5776 5777 if (data->regs_intr.regs) { 5778 u64 mask = event->attr.sample_regs_intr; 5779 5780 size += hweight64(mask) * sizeof(u64); 5781 } 5782 5783 header->size += size; 5784 } 5785 } 5786 5787 static void __always_inline 5788 __perf_event_output(struct perf_event *event, 5789 struct perf_sample_data *data, 5790 struct pt_regs *regs, 5791 int (*output_begin)(struct perf_output_handle *, 5792 struct perf_event *, 5793 unsigned int)) 5794 { 5795 struct perf_output_handle handle; 5796 struct perf_event_header header; 5797 5798 /* protect the callchain buffers */ 5799 rcu_read_lock(); 5800 5801 perf_prepare_sample(&header, data, event, regs); 5802 5803 if (output_begin(&handle, event, header.size)) 5804 goto exit; 5805 5806 perf_output_sample(&handle, &header, data, event); 5807 5808 perf_output_end(&handle); 5809 5810 exit: 5811 rcu_read_unlock(); 5812 } 5813 5814 void 5815 perf_event_output_forward(struct perf_event *event, 5816 struct perf_sample_data *data, 5817 struct pt_regs *regs) 5818 { 5819 __perf_event_output(event, data, regs, perf_output_begin_forward); 5820 } 5821 5822 void 5823 perf_event_output_backward(struct perf_event *event, 5824 struct perf_sample_data *data, 5825 struct pt_regs *regs) 5826 { 5827 __perf_event_output(event, data, regs, perf_output_begin_backward); 5828 } 5829 5830 void 5831 perf_event_output(struct perf_event *event, 5832 struct perf_sample_data *data, 5833 struct pt_regs *regs) 5834 { 5835 __perf_event_output(event, data, regs, perf_output_begin); 5836 } 5837 5838 /* 5839 * read event_id 5840 */ 5841 5842 struct perf_read_event { 5843 struct perf_event_header header; 5844 5845 u32 pid; 5846 u32 tid; 5847 }; 5848 5849 static void 5850 perf_event_read_event(struct perf_event *event, 5851 struct task_struct *task) 5852 { 5853 struct perf_output_handle handle; 5854 struct perf_sample_data sample; 5855 struct perf_read_event read_event = { 5856 .header = { 5857 .type = PERF_RECORD_READ, 5858 .misc = 0, 5859 .size = sizeof(read_event) + event->read_size, 5860 }, 5861 .pid = perf_event_pid(event, task), 5862 .tid = perf_event_tid(event, task), 5863 }; 5864 int ret; 5865 5866 perf_event_header__init_id(&read_event.header, &sample, event); 5867 ret = perf_output_begin(&handle, event, read_event.header.size); 5868 if (ret) 5869 return; 5870 5871 perf_output_put(&handle, read_event); 5872 perf_output_read(&handle, event); 5873 perf_event__output_id_sample(event, &handle, &sample); 5874 5875 perf_output_end(&handle); 5876 } 5877 5878 typedef void (perf_event_aux_output_cb)(struct perf_event *event, void *data); 5879 5880 static void 5881 perf_event_aux_ctx(struct perf_event_context *ctx, 5882 perf_event_aux_output_cb output, 5883 void *data, bool all) 5884 { 5885 struct perf_event *event; 5886 5887 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 5888 if (!all) { 5889 if (event->state < PERF_EVENT_STATE_INACTIVE) 5890 continue; 5891 if (!event_filter_match(event)) 5892 continue; 5893 } 5894 5895 output(event, data); 5896 } 5897 } 5898 5899 static void 5900 perf_event_aux_task_ctx(perf_event_aux_output_cb output, void *data, 5901 struct perf_event_context *task_ctx) 5902 { 5903 rcu_read_lock(); 5904 preempt_disable(); 5905 perf_event_aux_ctx(task_ctx, output, data, false); 5906 preempt_enable(); 5907 rcu_read_unlock(); 5908 } 5909 5910 static void 5911 perf_event_aux(perf_event_aux_output_cb output, void *data, 5912 struct perf_event_context *task_ctx) 5913 { 5914 struct perf_cpu_context *cpuctx; 5915 struct perf_event_context *ctx; 5916 struct pmu *pmu; 5917 int ctxn; 5918 5919 /* 5920 * If we have task_ctx != NULL we only notify 5921 * the task context itself. The task_ctx is set 5922 * only for EXIT events before releasing task 5923 * context. 5924 */ 5925 if (task_ctx) { 5926 perf_event_aux_task_ctx(output, data, task_ctx); 5927 return; 5928 } 5929 5930 rcu_read_lock(); 5931 list_for_each_entry_rcu(pmu, &pmus, entry) { 5932 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context); 5933 if (cpuctx->unique_pmu != pmu) 5934 goto next; 5935 perf_event_aux_ctx(&cpuctx->ctx, output, data, false); 5936 ctxn = pmu->task_ctx_nr; 5937 if (ctxn < 0) 5938 goto next; 5939 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); 5940 if (ctx) 5941 perf_event_aux_ctx(ctx, output, data, false); 5942 next: 5943 put_cpu_ptr(pmu->pmu_cpu_context); 5944 } 5945 rcu_read_unlock(); 5946 } 5947 5948 /* 5949 * Clear all file-based filters at exec, they'll have to be 5950 * re-instated when/if these objects are mmapped again. 5951 */ 5952 static void perf_event_addr_filters_exec(struct perf_event *event, void *data) 5953 { 5954 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 5955 struct perf_addr_filter *filter; 5956 unsigned int restart = 0, count = 0; 5957 unsigned long flags; 5958 5959 if (!has_addr_filter(event)) 5960 return; 5961 5962 raw_spin_lock_irqsave(&ifh->lock, flags); 5963 list_for_each_entry(filter, &ifh->list, entry) { 5964 if (filter->inode) { 5965 event->addr_filters_offs[count] = 0; 5966 restart++; 5967 } 5968 5969 count++; 5970 } 5971 5972 if (restart) 5973 event->addr_filters_gen++; 5974 raw_spin_unlock_irqrestore(&ifh->lock, flags); 5975 5976 if (restart) 5977 perf_event_restart(event); 5978 } 5979 5980 void perf_event_exec(void) 5981 { 5982 struct perf_event_context *ctx; 5983 int ctxn; 5984 5985 rcu_read_lock(); 5986 for_each_task_context_nr(ctxn) { 5987 ctx = current->perf_event_ctxp[ctxn]; 5988 if (!ctx) 5989 continue; 5990 5991 perf_event_enable_on_exec(ctxn); 5992 5993 perf_event_aux_ctx(ctx, perf_event_addr_filters_exec, NULL, 5994 true); 5995 } 5996 rcu_read_unlock(); 5997 } 5998 5999 struct remote_output { 6000 struct ring_buffer *rb; 6001 int err; 6002 }; 6003 6004 static void __perf_event_output_stop(struct perf_event *event, void *data) 6005 { 6006 struct perf_event *parent = event->parent; 6007 struct remote_output *ro = data; 6008 struct ring_buffer *rb = ro->rb; 6009 struct stop_event_data sd = { 6010 .event = event, 6011 }; 6012 6013 if (!has_aux(event)) 6014 return; 6015 6016 if (!parent) 6017 parent = event; 6018 6019 /* 6020 * In case of inheritance, it will be the parent that links to the 6021 * ring-buffer, but it will be the child that's actually using it: 6022 */ 6023 if (rcu_dereference(parent->rb) == rb) 6024 ro->err = __perf_event_stop(&sd); 6025 } 6026 6027 static int __perf_pmu_output_stop(void *info) 6028 { 6029 struct perf_event *event = info; 6030 struct pmu *pmu = event->pmu; 6031 struct perf_cpu_context *cpuctx = get_cpu_ptr(pmu->pmu_cpu_context); 6032 struct remote_output ro = { 6033 .rb = event->rb, 6034 }; 6035 6036 rcu_read_lock(); 6037 perf_event_aux_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false); 6038 if (cpuctx->task_ctx) 6039 perf_event_aux_ctx(cpuctx->task_ctx, __perf_event_output_stop, 6040 &ro, false); 6041 rcu_read_unlock(); 6042 6043 return ro.err; 6044 } 6045 6046 static void perf_pmu_output_stop(struct perf_event *event) 6047 { 6048 struct perf_event *iter; 6049 int err, cpu; 6050 6051 restart: 6052 rcu_read_lock(); 6053 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) { 6054 /* 6055 * For per-CPU events, we need to make sure that neither they 6056 * nor their children are running; for cpu==-1 events it's 6057 * sufficient to stop the event itself if it's active, since 6058 * it can't have children. 6059 */ 6060 cpu = iter->cpu; 6061 if (cpu == -1) 6062 cpu = READ_ONCE(iter->oncpu); 6063 6064 if (cpu == -1) 6065 continue; 6066 6067 err = cpu_function_call(cpu, __perf_pmu_output_stop, event); 6068 if (err == -EAGAIN) { 6069 rcu_read_unlock(); 6070 goto restart; 6071 } 6072 } 6073 rcu_read_unlock(); 6074 } 6075 6076 /* 6077 * task tracking -- fork/exit 6078 * 6079 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task 6080 */ 6081 6082 struct perf_task_event { 6083 struct task_struct *task; 6084 struct perf_event_context *task_ctx; 6085 6086 struct { 6087 struct perf_event_header header; 6088 6089 u32 pid; 6090 u32 ppid; 6091 u32 tid; 6092 u32 ptid; 6093 u64 time; 6094 } event_id; 6095 }; 6096 6097 static int perf_event_task_match(struct perf_event *event) 6098 { 6099 return event->attr.comm || event->attr.mmap || 6100 event->attr.mmap2 || event->attr.mmap_data || 6101 event->attr.task; 6102 } 6103 6104 static void perf_event_task_output(struct perf_event *event, 6105 void *data) 6106 { 6107 struct perf_task_event *task_event = data; 6108 struct perf_output_handle handle; 6109 struct perf_sample_data sample; 6110 struct task_struct *task = task_event->task; 6111 int ret, size = task_event->event_id.header.size; 6112 6113 if (!perf_event_task_match(event)) 6114 return; 6115 6116 perf_event_header__init_id(&task_event->event_id.header, &sample, event); 6117 6118 ret = perf_output_begin(&handle, event, 6119 task_event->event_id.header.size); 6120 if (ret) 6121 goto out; 6122 6123 task_event->event_id.pid = perf_event_pid(event, task); 6124 task_event->event_id.ppid = perf_event_pid(event, current); 6125 6126 task_event->event_id.tid = perf_event_tid(event, task); 6127 task_event->event_id.ptid = perf_event_tid(event, current); 6128 6129 task_event->event_id.time = perf_event_clock(event); 6130 6131 perf_output_put(&handle, task_event->event_id); 6132 6133 perf_event__output_id_sample(event, &handle, &sample); 6134 6135 perf_output_end(&handle); 6136 out: 6137 task_event->event_id.header.size = size; 6138 } 6139 6140 static void perf_event_task(struct task_struct *task, 6141 struct perf_event_context *task_ctx, 6142 int new) 6143 { 6144 struct perf_task_event task_event; 6145 6146 if (!atomic_read(&nr_comm_events) && 6147 !atomic_read(&nr_mmap_events) && 6148 !atomic_read(&nr_task_events)) 6149 return; 6150 6151 task_event = (struct perf_task_event){ 6152 .task = task, 6153 .task_ctx = task_ctx, 6154 .event_id = { 6155 .header = { 6156 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT, 6157 .misc = 0, 6158 .size = sizeof(task_event.event_id), 6159 }, 6160 /* .pid */ 6161 /* .ppid */ 6162 /* .tid */ 6163 /* .ptid */ 6164 /* .time */ 6165 }, 6166 }; 6167 6168 perf_event_aux(perf_event_task_output, 6169 &task_event, 6170 task_ctx); 6171 } 6172 6173 void perf_event_fork(struct task_struct *task) 6174 { 6175 perf_event_task(task, NULL, 1); 6176 } 6177 6178 /* 6179 * comm tracking 6180 */ 6181 6182 struct perf_comm_event { 6183 struct task_struct *task; 6184 char *comm; 6185 int comm_size; 6186 6187 struct { 6188 struct perf_event_header header; 6189 6190 u32 pid; 6191 u32 tid; 6192 } event_id; 6193 }; 6194 6195 static int perf_event_comm_match(struct perf_event *event) 6196 { 6197 return event->attr.comm; 6198 } 6199 6200 static void perf_event_comm_output(struct perf_event *event, 6201 void *data) 6202 { 6203 struct perf_comm_event *comm_event = data; 6204 struct perf_output_handle handle; 6205 struct perf_sample_data sample; 6206 int size = comm_event->event_id.header.size; 6207 int ret; 6208 6209 if (!perf_event_comm_match(event)) 6210 return; 6211 6212 perf_event_header__init_id(&comm_event->event_id.header, &sample, event); 6213 ret = perf_output_begin(&handle, event, 6214 comm_event->event_id.header.size); 6215 6216 if (ret) 6217 goto out; 6218 6219 comm_event->event_id.pid = perf_event_pid(event, comm_event->task); 6220 comm_event->event_id.tid = perf_event_tid(event, comm_event->task); 6221 6222 perf_output_put(&handle, comm_event->event_id); 6223 __output_copy(&handle, comm_event->comm, 6224 comm_event->comm_size); 6225 6226 perf_event__output_id_sample(event, &handle, &sample); 6227 6228 perf_output_end(&handle); 6229 out: 6230 comm_event->event_id.header.size = size; 6231 } 6232 6233 static void perf_event_comm_event(struct perf_comm_event *comm_event) 6234 { 6235 char comm[TASK_COMM_LEN]; 6236 unsigned int size; 6237 6238 memset(comm, 0, sizeof(comm)); 6239 strlcpy(comm, comm_event->task->comm, sizeof(comm)); 6240 size = ALIGN(strlen(comm)+1, sizeof(u64)); 6241 6242 comm_event->comm = comm; 6243 comm_event->comm_size = size; 6244 6245 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size; 6246 6247 perf_event_aux(perf_event_comm_output, 6248 comm_event, 6249 NULL); 6250 } 6251 6252 void perf_event_comm(struct task_struct *task, bool exec) 6253 { 6254 struct perf_comm_event comm_event; 6255 6256 if (!atomic_read(&nr_comm_events)) 6257 return; 6258 6259 comm_event = (struct perf_comm_event){ 6260 .task = task, 6261 /* .comm */ 6262 /* .comm_size */ 6263 .event_id = { 6264 .header = { 6265 .type = PERF_RECORD_COMM, 6266 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0, 6267 /* .size */ 6268 }, 6269 /* .pid */ 6270 /* .tid */ 6271 }, 6272 }; 6273 6274 perf_event_comm_event(&comm_event); 6275 } 6276 6277 /* 6278 * mmap tracking 6279 */ 6280 6281 struct perf_mmap_event { 6282 struct vm_area_struct *vma; 6283 6284 const char *file_name; 6285 int file_size; 6286 int maj, min; 6287 u64 ino; 6288 u64 ino_generation; 6289 u32 prot, flags; 6290 6291 struct { 6292 struct perf_event_header header; 6293 6294 u32 pid; 6295 u32 tid; 6296 u64 start; 6297 u64 len; 6298 u64 pgoff; 6299 } event_id; 6300 }; 6301 6302 static int perf_event_mmap_match(struct perf_event *event, 6303 void *data) 6304 { 6305 struct perf_mmap_event *mmap_event = data; 6306 struct vm_area_struct *vma = mmap_event->vma; 6307 int executable = vma->vm_flags & VM_EXEC; 6308 6309 return (!executable && event->attr.mmap_data) || 6310 (executable && (event->attr.mmap || event->attr.mmap2)); 6311 } 6312 6313 static void perf_event_mmap_output(struct perf_event *event, 6314 void *data) 6315 { 6316 struct perf_mmap_event *mmap_event = data; 6317 struct perf_output_handle handle; 6318 struct perf_sample_data sample; 6319 int size = mmap_event->event_id.header.size; 6320 int ret; 6321 6322 if (!perf_event_mmap_match(event, data)) 6323 return; 6324 6325 if (event->attr.mmap2) { 6326 mmap_event->event_id.header.type = PERF_RECORD_MMAP2; 6327 mmap_event->event_id.header.size += sizeof(mmap_event->maj); 6328 mmap_event->event_id.header.size += sizeof(mmap_event->min); 6329 mmap_event->event_id.header.size += sizeof(mmap_event->ino); 6330 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation); 6331 mmap_event->event_id.header.size += sizeof(mmap_event->prot); 6332 mmap_event->event_id.header.size += sizeof(mmap_event->flags); 6333 } 6334 6335 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event); 6336 ret = perf_output_begin(&handle, event, 6337 mmap_event->event_id.header.size); 6338 if (ret) 6339 goto out; 6340 6341 mmap_event->event_id.pid = perf_event_pid(event, current); 6342 mmap_event->event_id.tid = perf_event_tid(event, current); 6343 6344 perf_output_put(&handle, mmap_event->event_id); 6345 6346 if (event->attr.mmap2) { 6347 perf_output_put(&handle, mmap_event->maj); 6348 perf_output_put(&handle, mmap_event->min); 6349 perf_output_put(&handle, mmap_event->ino); 6350 perf_output_put(&handle, mmap_event->ino_generation); 6351 perf_output_put(&handle, mmap_event->prot); 6352 perf_output_put(&handle, mmap_event->flags); 6353 } 6354 6355 __output_copy(&handle, mmap_event->file_name, 6356 mmap_event->file_size); 6357 6358 perf_event__output_id_sample(event, &handle, &sample); 6359 6360 perf_output_end(&handle); 6361 out: 6362 mmap_event->event_id.header.size = size; 6363 } 6364 6365 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) 6366 { 6367 struct vm_area_struct *vma = mmap_event->vma; 6368 struct file *file = vma->vm_file; 6369 int maj = 0, min = 0; 6370 u64 ino = 0, gen = 0; 6371 u32 prot = 0, flags = 0; 6372 unsigned int size; 6373 char tmp[16]; 6374 char *buf = NULL; 6375 char *name; 6376 6377 if (file) { 6378 struct inode *inode; 6379 dev_t dev; 6380 6381 buf = kmalloc(PATH_MAX, GFP_KERNEL); 6382 if (!buf) { 6383 name = "//enomem"; 6384 goto cpy_name; 6385 } 6386 /* 6387 * d_path() works from the end of the rb backwards, so we 6388 * need to add enough zero bytes after the string to handle 6389 * the 64bit alignment we do later. 6390 */ 6391 name = file_path(file, buf, PATH_MAX - sizeof(u64)); 6392 if (IS_ERR(name)) { 6393 name = "//toolong"; 6394 goto cpy_name; 6395 } 6396 inode = file_inode(vma->vm_file); 6397 dev = inode->i_sb->s_dev; 6398 ino = inode->i_ino; 6399 gen = inode->i_generation; 6400 maj = MAJOR(dev); 6401 min = MINOR(dev); 6402 6403 if (vma->vm_flags & VM_READ) 6404 prot |= PROT_READ; 6405 if (vma->vm_flags & VM_WRITE) 6406 prot |= PROT_WRITE; 6407 if (vma->vm_flags & VM_EXEC) 6408 prot |= PROT_EXEC; 6409 6410 if (vma->vm_flags & VM_MAYSHARE) 6411 flags = MAP_SHARED; 6412 else 6413 flags = MAP_PRIVATE; 6414 6415 if (vma->vm_flags & VM_DENYWRITE) 6416 flags |= MAP_DENYWRITE; 6417 if (vma->vm_flags & VM_MAYEXEC) 6418 flags |= MAP_EXECUTABLE; 6419 if (vma->vm_flags & VM_LOCKED) 6420 flags |= MAP_LOCKED; 6421 if (vma->vm_flags & VM_HUGETLB) 6422 flags |= MAP_HUGETLB; 6423 6424 goto got_name; 6425 } else { 6426 if (vma->vm_ops && vma->vm_ops->name) { 6427 name = (char *) vma->vm_ops->name(vma); 6428 if (name) 6429 goto cpy_name; 6430 } 6431 6432 name = (char *)arch_vma_name(vma); 6433 if (name) 6434 goto cpy_name; 6435 6436 if (vma->vm_start <= vma->vm_mm->start_brk && 6437 vma->vm_end >= vma->vm_mm->brk) { 6438 name = "[heap]"; 6439 goto cpy_name; 6440 } 6441 if (vma->vm_start <= vma->vm_mm->start_stack && 6442 vma->vm_end >= vma->vm_mm->start_stack) { 6443 name = "[stack]"; 6444 goto cpy_name; 6445 } 6446 6447 name = "//anon"; 6448 goto cpy_name; 6449 } 6450 6451 cpy_name: 6452 strlcpy(tmp, name, sizeof(tmp)); 6453 name = tmp; 6454 got_name: 6455 /* 6456 * Since our buffer works in 8 byte units we need to align our string 6457 * size to a multiple of 8. However, we must guarantee the tail end is 6458 * zero'd out to avoid leaking random bits to userspace. 6459 */ 6460 size = strlen(name)+1; 6461 while (!IS_ALIGNED(size, sizeof(u64))) 6462 name[size++] = '\0'; 6463 6464 mmap_event->file_name = name; 6465 mmap_event->file_size = size; 6466 mmap_event->maj = maj; 6467 mmap_event->min = min; 6468 mmap_event->ino = ino; 6469 mmap_event->ino_generation = gen; 6470 mmap_event->prot = prot; 6471 mmap_event->flags = flags; 6472 6473 if (!(vma->vm_flags & VM_EXEC)) 6474 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA; 6475 6476 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size; 6477 6478 perf_event_aux(perf_event_mmap_output, 6479 mmap_event, 6480 NULL); 6481 6482 kfree(buf); 6483 } 6484 6485 /* 6486 * Whether this @filter depends on a dynamic object which is not loaded 6487 * yet or its load addresses are not known. 6488 */ 6489 static bool perf_addr_filter_needs_mmap(struct perf_addr_filter *filter) 6490 { 6491 return filter->filter && filter->inode; 6492 } 6493 6494 /* 6495 * Check whether inode and address range match filter criteria. 6496 */ 6497 static bool perf_addr_filter_match(struct perf_addr_filter *filter, 6498 struct file *file, unsigned long offset, 6499 unsigned long size) 6500 { 6501 if (filter->inode != file->f_inode) 6502 return false; 6503 6504 if (filter->offset > offset + size) 6505 return false; 6506 6507 if (filter->offset + filter->size < offset) 6508 return false; 6509 6510 return true; 6511 } 6512 6513 static void __perf_addr_filters_adjust(struct perf_event *event, void *data) 6514 { 6515 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 6516 struct vm_area_struct *vma = data; 6517 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags; 6518 struct file *file = vma->vm_file; 6519 struct perf_addr_filter *filter; 6520 unsigned int restart = 0, count = 0; 6521 6522 if (!has_addr_filter(event)) 6523 return; 6524 6525 if (!file) 6526 return; 6527 6528 raw_spin_lock_irqsave(&ifh->lock, flags); 6529 list_for_each_entry(filter, &ifh->list, entry) { 6530 if (perf_addr_filter_match(filter, file, off, 6531 vma->vm_end - vma->vm_start)) { 6532 event->addr_filters_offs[count] = vma->vm_start; 6533 restart++; 6534 } 6535 6536 count++; 6537 } 6538 6539 if (restart) 6540 event->addr_filters_gen++; 6541 raw_spin_unlock_irqrestore(&ifh->lock, flags); 6542 6543 if (restart) 6544 perf_event_restart(event); 6545 } 6546 6547 /* 6548 * Adjust all task's events' filters to the new vma 6549 */ 6550 static void perf_addr_filters_adjust(struct vm_area_struct *vma) 6551 { 6552 struct perf_event_context *ctx; 6553 int ctxn; 6554 6555 rcu_read_lock(); 6556 for_each_task_context_nr(ctxn) { 6557 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); 6558 if (!ctx) 6559 continue; 6560 6561 perf_event_aux_ctx(ctx, __perf_addr_filters_adjust, vma, true); 6562 } 6563 rcu_read_unlock(); 6564 } 6565 6566 void perf_event_mmap(struct vm_area_struct *vma) 6567 { 6568 struct perf_mmap_event mmap_event; 6569 6570 if (!atomic_read(&nr_mmap_events)) 6571 return; 6572 6573 mmap_event = (struct perf_mmap_event){ 6574 .vma = vma, 6575 /* .file_name */ 6576 /* .file_size */ 6577 .event_id = { 6578 .header = { 6579 .type = PERF_RECORD_MMAP, 6580 .misc = PERF_RECORD_MISC_USER, 6581 /* .size */ 6582 }, 6583 /* .pid */ 6584 /* .tid */ 6585 .start = vma->vm_start, 6586 .len = vma->vm_end - vma->vm_start, 6587 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT, 6588 }, 6589 /* .maj (attr_mmap2 only) */ 6590 /* .min (attr_mmap2 only) */ 6591 /* .ino (attr_mmap2 only) */ 6592 /* .ino_generation (attr_mmap2 only) */ 6593 /* .prot (attr_mmap2 only) */ 6594 /* .flags (attr_mmap2 only) */ 6595 }; 6596 6597 perf_addr_filters_adjust(vma); 6598 perf_event_mmap_event(&mmap_event); 6599 } 6600 6601 void perf_event_aux_event(struct perf_event *event, unsigned long head, 6602 unsigned long size, u64 flags) 6603 { 6604 struct perf_output_handle handle; 6605 struct perf_sample_data sample; 6606 struct perf_aux_event { 6607 struct perf_event_header header; 6608 u64 offset; 6609 u64 size; 6610 u64 flags; 6611 } rec = { 6612 .header = { 6613 .type = PERF_RECORD_AUX, 6614 .misc = 0, 6615 .size = sizeof(rec), 6616 }, 6617 .offset = head, 6618 .size = size, 6619 .flags = flags, 6620 }; 6621 int ret; 6622 6623 perf_event_header__init_id(&rec.header, &sample, event); 6624 ret = perf_output_begin(&handle, event, rec.header.size); 6625 6626 if (ret) 6627 return; 6628 6629 perf_output_put(&handle, rec); 6630 perf_event__output_id_sample(event, &handle, &sample); 6631 6632 perf_output_end(&handle); 6633 } 6634 6635 /* 6636 * Lost/dropped samples logging 6637 */ 6638 void perf_log_lost_samples(struct perf_event *event, u64 lost) 6639 { 6640 struct perf_output_handle handle; 6641 struct perf_sample_data sample; 6642 int ret; 6643 6644 struct { 6645 struct perf_event_header header; 6646 u64 lost; 6647 } lost_samples_event = { 6648 .header = { 6649 .type = PERF_RECORD_LOST_SAMPLES, 6650 .misc = 0, 6651 .size = sizeof(lost_samples_event), 6652 }, 6653 .lost = lost, 6654 }; 6655 6656 perf_event_header__init_id(&lost_samples_event.header, &sample, event); 6657 6658 ret = perf_output_begin(&handle, event, 6659 lost_samples_event.header.size); 6660 if (ret) 6661 return; 6662 6663 perf_output_put(&handle, lost_samples_event); 6664 perf_event__output_id_sample(event, &handle, &sample); 6665 perf_output_end(&handle); 6666 } 6667 6668 /* 6669 * context_switch tracking 6670 */ 6671 6672 struct perf_switch_event { 6673 struct task_struct *task; 6674 struct task_struct *next_prev; 6675 6676 struct { 6677 struct perf_event_header header; 6678 u32 next_prev_pid; 6679 u32 next_prev_tid; 6680 } event_id; 6681 }; 6682 6683 static int perf_event_switch_match(struct perf_event *event) 6684 { 6685 return event->attr.context_switch; 6686 } 6687 6688 static void perf_event_switch_output(struct perf_event *event, void *data) 6689 { 6690 struct perf_switch_event *se = data; 6691 struct perf_output_handle handle; 6692 struct perf_sample_data sample; 6693 int ret; 6694 6695 if (!perf_event_switch_match(event)) 6696 return; 6697 6698 /* Only CPU-wide events are allowed to see next/prev pid/tid */ 6699 if (event->ctx->task) { 6700 se->event_id.header.type = PERF_RECORD_SWITCH; 6701 se->event_id.header.size = sizeof(se->event_id.header); 6702 } else { 6703 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE; 6704 se->event_id.header.size = sizeof(se->event_id); 6705 se->event_id.next_prev_pid = 6706 perf_event_pid(event, se->next_prev); 6707 se->event_id.next_prev_tid = 6708 perf_event_tid(event, se->next_prev); 6709 } 6710 6711 perf_event_header__init_id(&se->event_id.header, &sample, event); 6712 6713 ret = perf_output_begin(&handle, event, se->event_id.header.size); 6714 if (ret) 6715 return; 6716 6717 if (event->ctx->task) 6718 perf_output_put(&handle, se->event_id.header); 6719 else 6720 perf_output_put(&handle, se->event_id); 6721 6722 perf_event__output_id_sample(event, &handle, &sample); 6723 6724 perf_output_end(&handle); 6725 } 6726 6727 static void perf_event_switch(struct task_struct *task, 6728 struct task_struct *next_prev, bool sched_in) 6729 { 6730 struct perf_switch_event switch_event; 6731 6732 /* N.B. caller checks nr_switch_events != 0 */ 6733 6734 switch_event = (struct perf_switch_event){ 6735 .task = task, 6736 .next_prev = next_prev, 6737 .event_id = { 6738 .header = { 6739 /* .type */ 6740 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT, 6741 /* .size */ 6742 }, 6743 /* .next_prev_pid */ 6744 /* .next_prev_tid */ 6745 }, 6746 }; 6747 6748 perf_event_aux(perf_event_switch_output, 6749 &switch_event, 6750 NULL); 6751 } 6752 6753 /* 6754 * IRQ throttle logging 6755 */ 6756 6757 static void perf_log_throttle(struct perf_event *event, int enable) 6758 { 6759 struct perf_output_handle handle; 6760 struct perf_sample_data sample; 6761 int ret; 6762 6763 struct { 6764 struct perf_event_header header; 6765 u64 time; 6766 u64 id; 6767 u64 stream_id; 6768 } throttle_event = { 6769 .header = { 6770 .type = PERF_RECORD_THROTTLE, 6771 .misc = 0, 6772 .size = sizeof(throttle_event), 6773 }, 6774 .time = perf_event_clock(event), 6775 .id = primary_event_id(event), 6776 .stream_id = event->id, 6777 }; 6778 6779 if (enable) 6780 throttle_event.header.type = PERF_RECORD_UNTHROTTLE; 6781 6782 perf_event_header__init_id(&throttle_event.header, &sample, event); 6783 6784 ret = perf_output_begin(&handle, event, 6785 throttle_event.header.size); 6786 if (ret) 6787 return; 6788 6789 perf_output_put(&handle, throttle_event); 6790 perf_event__output_id_sample(event, &handle, &sample); 6791 perf_output_end(&handle); 6792 } 6793 6794 static void perf_log_itrace_start(struct perf_event *event) 6795 { 6796 struct perf_output_handle handle; 6797 struct perf_sample_data sample; 6798 struct perf_aux_event { 6799 struct perf_event_header header; 6800 u32 pid; 6801 u32 tid; 6802 } rec; 6803 int ret; 6804 6805 if (event->parent) 6806 event = event->parent; 6807 6808 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) || 6809 event->hw.itrace_started) 6810 return; 6811 6812 rec.header.type = PERF_RECORD_ITRACE_START; 6813 rec.header.misc = 0; 6814 rec.header.size = sizeof(rec); 6815 rec.pid = perf_event_pid(event, current); 6816 rec.tid = perf_event_tid(event, current); 6817 6818 perf_event_header__init_id(&rec.header, &sample, event); 6819 ret = perf_output_begin(&handle, event, rec.header.size); 6820 6821 if (ret) 6822 return; 6823 6824 perf_output_put(&handle, rec); 6825 perf_event__output_id_sample(event, &handle, &sample); 6826 6827 perf_output_end(&handle); 6828 } 6829 6830 /* 6831 * Generic event overflow handling, sampling. 6832 */ 6833 6834 static int __perf_event_overflow(struct perf_event *event, 6835 int throttle, struct perf_sample_data *data, 6836 struct pt_regs *regs) 6837 { 6838 int events = atomic_read(&event->event_limit); 6839 struct hw_perf_event *hwc = &event->hw; 6840 u64 seq; 6841 int ret = 0; 6842 6843 /* 6844 * Non-sampling counters might still use the PMI to fold short 6845 * hardware counters, ignore those. 6846 */ 6847 if (unlikely(!is_sampling_event(event))) 6848 return 0; 6849 6850 seq = __this_cpu_read(perf_throttled_seq); 6851 if (seq != hwc->interrupts_seq) { 6852 hwc->interrupts_seq = seq; 6853 hwc->interrupts = 1; 6854 } else { 6855 hwc->interrupts++; 6856 if (unlikely(throttle 6857 && hwc->interrupts >= max_samples_per_tick)) { 6858 __this_cpu_inc(perf_throttled_count); 6859 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); 6860 hwc->interrupts = MAX_INTERRUPTS; 6861 perf_log_throttle(event, 0); 6862 ret = 1; 6863 } 6864 } 6865 6866 if (event->attr.freq) { 6867 u64 now = perf_clock(); 6868 s64 delta = now - hwc->freq_time_stamp; 6869 6870 hwc->freq_time_stamp = now; 6871 6872 if (delta > 0 && delta < 2*TICK_NSEC) 6873 perf_adjust_period(event, delta, hwc->last_period, true); 6874 } 6875 6876 /* 6877 * XXX event_limit might not quite work as expected on inherited 6878 * events 6879 */ 6880 6881 event->pending_kill = POLL_IN; 6882 if (events && atomic_dec_and_test(&event->event_limit)) { 6883 ret = 1; 6884 event->pending_kill = POLL_HUP; 6885 event->pending_disable = 1; 6886 irq_work_queue(&event->pending); 6887 } 6888 6889 event->overflow_handler(event, data, regs); 6890 6891 if (*perf_event_fasync(event) && event->pending_kill) { 6892 event->pending_wakeup = 1; 6893 irq_work_queue(&event->pending); 6894 } 6895 6896 return ret; 6897 } 6898 6899 int perf_event_overflow(struct perf_event *event, 6900 struct perf_sample_data *data, 6901 struct pt_regs *regs) 6902 { 6903 return __perf_event_overflow(event, 1, data, regs); 6904 } 6905 6906 /* 6907 * Generic software event infrastructure 6908 */ 6909 6910 struct swevent_htable { 6911 struct swevent_hlist *swevent_hlist; 6912 struct mutex hlist_mutex; 6913 int hlist_refcount; 6914 6915 /* Recursion avoidance in each contexts */ 6916 int recursion[PERF_NR_CONTEXTS]; 6917 }; 6918 6919 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable); 6920 6921 /* 6922 * We directly increment event->count and keep a second value in 6923 * event->hw.period_left to count intervals. This period event 6924 * is kept in the range [-sample_period, 0] so that we can use the 6925 * sign as trigger. 6926 */ 6927 6928 u64 perf_swevent_set_period(struct perf_event *event) 6929 { 6930 struct hw_perf_event *hwc = &event->hw; 6931 u64 period = hwc->last_period; 6932 u64 nr, offset; 6933 s64 old, val; 6934 6935 hwc->last_period = hwc->sample_period; 6936 6937 again: 6938 old = val = local64_read(&hwc->period_left); 6939 if (val < 0) 6940 return 0; 6941 6942 nr = div64_u64(period + val, period); 6943 offset = nr * period; 6944 val -= offset; 6945 if (local64_cmpxchg(&hwc->period_left, old, val) != old) 6946 goto again; 6947 6948 return nr; 6949 } 6950 6951 static void perf_swevent_overflow(struct perf_event *event, u64 overflow, 6952 struct perf_sample_data *data, 6953 struct pt_regs *regs) 6954 { 6955 struct hw_perf_event *hwc = &event->hw; 6956 int throttle = 0; 6957 6958 if (!overflow) 6959 overflow = perf_swevent_set_period(event); 6960 6961 if (hwc->interrupts == MAX_INTERRUPTS) 6962 return; 6963 6964 for (; overflow; overflow--) { 6965 if (__perf_event_overflow(event, throttle, 6966 data, regs)) { 6967 /* 6968 * We inhibit the overflow from happening when 6969 * hwc->interrupts == MAX_INTERRUPTS. 6970 */ 6971 break; 6972 } 6973 throttle = 1; 6974 } 6975 } 6976 6977 static void perf_swevent_event(struct perf_event *event, u64 nr, 6978 struct perf_sample_data *data, 6979 struct pt_regs *regs) 6980 { 6981 struct hw_perf_event *hwc = &event->hw; 6982 6983 local64_add(nr, &event->count); 6984 6985 if (!regs) 6986 return; 6987 6988 if (!is_sampling_event(event)) 6989 return; 6990 6991 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) { 6992 data->period = nr; 6993 return perf_swevent_overflow(event, 1, data, regs); 6994 } else 6995 data->period = event->hw.last_period; 6996 6997 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq) 6998 return perf_swevent_overflow(event, 1, data, regs); 6999 7000 if (local64_add_negative(nr, &hwc->period_left)) 7001 return; 7002 7003 perf_swevent_overflow(event, 0, data, regs); 7004 } 7005 7006 static int perf_exclude_event(struct perf_event *event, 7007 struct pt_regs *regs) 7008 { 7009 if (event->hw.state & PERF_HES_STOPPED) 7010 return 1; 7011 7012 if (regs) { 7013 if (event->attr.exclude_user && user_mode(regs)) 7014 return 1; 7015 7016 if (event->attr.exclude_kernel && !user_mode(regs)) 7017 return 1; 7018 } 7019 7020 return 0; 7021 } 7022 7023 static int perf_swevent_match(struct perf_event *event, 7024 enum perf_type_id type, 7025 u32 event_id, 7026 struct perf_sample_data *data, 7027 struct pt_regs *regs) 7028 { 7029 if (event->attr.type != type) 7030 return 0; 7031 7032 if (event->attr.config != event_id) 7033 return 0; 7034 7035 if (perf_exclude_event(event, regs)) 7036 return 0; 7037 7038 return 1; 7039 } 7040 7041 static inline u64 swevent_hash(u64 type, u32 event_id) 7042 { 7043 u64 val = event_id | (type << 32); 7044 7045 return hash_64(val, SWEVENT_HLIST_BITS); 7046 } 7047 7048 static inline struct hlist_head * 7049 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id) 7050 { 7051 u64 hash = swevent_hash(type, event_id); 7052 7053 return &hlist->heads[hash]; 7054 } 7055 7056 /* For the read side: events when they trigger */ 7057 static inline struct hlist_head * 7058 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id) 7059 { 7060 struct swevent_hlist *hlist; 7061 7062 hlist = rcu_dereference(swhash->swevent_hlist); 7063 if (!hlist) 7064 return NULL; 7065 7066 return __find_swevent_head(hlist, type, event_id); 7067 } 7068 7069 /* For the event head insertion and removal in the hlist */ 7070 static inline struct hlist_head * 7071 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event) 7072 { 7073 struct swevent_hlist *hlist; 7074 u32 event_id = event->attr.config; 7075 u64 type = event->attr.type; 7076 7077 /* 7078 * Event scheduling is always serialized against hlist allocation 7079 * and release. Which makes the protected version suitable here. 7080 * The context lock guarantees that. 7081 */ 7082 hlist = rcu_dereference_protected(swhash->swevent_hlist, 7083 lockdep_is_held(&event->ctx->lock)); 7084 if (!hlist) 7085 return NULL; 7086 7087 return __find_swevent_head(hlist, type, event_id); 7088 } 7089 7090 static void do_perf_sw_event(enum perf_type_id type, u32 event_id, 7091 u64 nr, 7092 struct perf_sample_data *data, 7093 struct pt_regs *regs) 7094 { 7095 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 7096 struct perf_event *event; 7097 struct hlist_head *head; 7098 7099 rcu_read_lock(); 7100 head = find_swevent_head_rcu(swhash, type, event_id); 7101 if (!head) 7102 goto end; 7103 7104 hlist_for_each_entry_rcu(event, head, hlist_entry) { 7105 if (perf_swevent_match(event, type, event_id, data, regs)) 7106 perf_swevent_event(event, nr, data, regs); 7107 } 7108 end: 7109 rcu_read_unlock(); 7110 } 7111 7112 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]); 7113 7114 int perf_swevent_get_recursion_context(void) 7115 { 7116 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 7117 7118 return get_recursion_context(swhash->recursion); 7119 } 7120 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context); 7121 7122 void perf_swevent_put_recursion_context(int rctx) 7123 { 7124 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 7125 7126 put_recursion_context(swhash->recursion, rctx); 7127 } 7128 7129 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) 7130 { 7131 struct perf_sample_data data; 7132 7133 if (WARN_ON_ONCE(!regs)) 7134 return; 7135 7136 perf_sample_data_init(&data, addr, 0); 7137 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs); 7138 } 7139 7140 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) 7141 { 7142 int rctx; 7143 7144 preempt_disable_notrace(); 7145 rctx = perf_swevent_get_recursion_context(); 7146 if (unlikely(rctx < 0)) 7147 goto fail; 7148 7149 ___perf_sw_event(event_id, nr, regs, addr); 7150 7151 perf_swevent_put_recursion_context(rctx); 7152 fail: 7153 preempt_enable_notrace(); 7154 } 7155 7156 static void perf_swevent_read(struct perf_event *event) 7157 { 7158 } 7159 7160 static int perf_swevent_add(struct perf_event *event, int flags) 7161 { 7162 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 7163 struct hw_perf_event *hwc = &event->hw; 7164 struct hlist_head *head; 7165 7166 if (is_sampling_event(event)) { 7167 hwc->last_period = hwc->sample_period; 7168 perf_swevent_set_period(event); 7169 } 7170 7171 hwc->state = !(flags & PERF_EF_START); 7172 7173 head = find_swevent_head(swhash, event); 7174 if (WARN_ON_ONCE(!head)) 7175 return -EINVAL; 7176 7177 hlist_add_head_rcu(&event->hlist_entry, head); 7178 perf_event_update_userpage(event); 7179 7180 return 0; 7181 } 7182 7183 static void perf_swevent_del(struct perf_event *event, int flags) 7184 { 7185 hlist_del_rcu(&event->hlist_entry); 7186 } 7187 7188 static void perf_swevent_start(struct perf_event *event, int flags) 7189 { 7190 event->hw.state = 0; 7191 } 7192 7193 static void perf_swevent_stop(struct perf_event *event, int flags) 7194 { 7195 event->hw.state = PERF_HES_STOPPED; 7196 } 7197 7198 /* Deref the hlist from the update side */ 7199 static inline struct swevent_hlist * 7200 swevent_hlist_deref(struct swevent_htable *swhash) 7201 { 7202 return rcu_dereference_protected(swhash->swevent_hlist, 7203 lockdep_is_held(&swhash->hlist_mutex)); 7204 } 7205 7206 static void swevent_hlist_release(struct swevent_htable *swhash) 7207 { 7208 struct swevent_hlist *hlist = swevent_hlist_deref(swhash); 7209 7210 if (!hlist) 7211 return; 7212 7213 RCU_INIT_POINTER(swhash->swevent_hlist, NULL); 7214 kfree_rcu(hlist, rcu_head); 7215 } 7216 7217 static void swevent_hlist_put_cpu(int cpu) 7218 { 7219 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 7220 7221 mutex_lock(&swhash->hlist_mutex); 7222 7223 if (!--swhash->hlist_refcount) 7224 swevent_hlist_release(swhash); 7225 7226 mutex_unlock(&swhash->hlist_mutex); 7227 } 7228 7229 static void swevent_hlist_put(void) 7230 { 7231 int cpu; 7232 7233 for_each_possible_cpu(cpu) 7234 swevent_hlist_put_cpu(cpu); 7235 } 7236 7237 static int swevent_hlist_get_cpu(int cpu) 7238 { 7239 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 7240 int err = 0; 7241 7242 mutex_lock(&swhash->hlist_mutex); 7243 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) { 7244 struct swevent_hlist *hlist; 7245 7246 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL); 7247 if (!hlist) { 7248 err = -ENOMEM; 7249 goto exit; 7250 } 7251 rcu_assign_pointer(swhash->swevent_hlist, hlist); 7252 } 7253 swhash->hlist_refcount++; 7254 exit: 7255 mutex_unlock(&swhash->hlist_mutex); 7256 7257 return err; 7258 } 7259 7260 static int swevent_hlist_get(void) 7261 { 7262 int err, cpu, failed_cpu; 7263 7264 get_online_cpus(); 7265 for_each_possible_cpu(cpu) { 7266 err = swevent_hlist_get_cpu(cpu); 7267 if (err) { 7268 failed_cpu = cpu; 7269 goto fail; 7270 } 7271 } 7272 put_online_cpus(); 7273 7274 return 0; 7275 fail: 7276 for_each_possible_cpu(cpu) { 7277 if (cpu == failed_cpu) 7278 break; 7279 swevent_hlist_put_cpu(cpu); 7280 } 7281 7282 put_online_cpus(); 7283 return err; 7284 } 7285 7286 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX]; 7287 7288 static void sw_perf_event_destroy(struct perf_event *event) 7289 { 7290 u64 event_id = event->attr.config; 7291 7292 WARN_ON(event->parent); 7293 7294 static_key_slow_dec(&perf_swevent_enabled[event_id]); 7295 swevent_hlist_put(); 7296 } 7297 7298 static int perf_swevent_init(struct perf_event *event) 7299 { 7300 u64 event_id = event->attr.config; 7301 7302 if (event->attr.type != PERF_TYPE_SOFTWARE) 7303 return -ENOENT; 7304 7305 /* 7306 * no branch sampling for software events 7307 */ 7308 if (has_branch_stack(event)) 7309 return -EOPNOTSUPP; 7310 7311 switch (event_id) { 7312 case PERF_COUNT_SW_CPU_CLOCK: 7313 case PERF_COUNT_SW_TASK_CLOCK: 7314 return -ENOENT; 7315 7316 default: 7317 break; 7318 } 7319 7320 if (event_id >= PERF_COUNT_SW_MAX) 7321 return -ENOENT; 7322 7323 if (!event->parent) { 7324 int err; 7325 7326 err = swevent_hlist_get(); 7327 if (err) 7328 return err; 7329 7330 static_key_slow_inc(&perf_swevent_enabled[event_id]); 7331 event->destroy = sw_perf_event_destroy; 7332 } 7333 7334 return 0; 7335 } 7336 7337 static struct pmu perf_swevent = { 7338 .task_ctx_nr = perf_sw_context, 7339 7340 .capabilities = PERF_PMU_CAP_NO_NMI, 7341 7342 .event_init = perf_swevent_init, 7343 .add = perf_swevent_add, 7344 .del = perf_swevent_del, 7345 .start = perf_swevent_start, 7346 .stop = perf_swevent_stop, 7347 .read = perf_swevent_read, 7348 }; 7349 7350 #ifdef CONFIG_EVENT_TRACING 7351 7352 static int perf_tp_filter_match(struct perf_event *event, 7353 struct perf_sample_data *data) 7354 { 7355 void *record = data->raw->data; 7356 7357 /* only top level events have filters set */ 7358 if (event->parent) 7359 event = event->parent; 7360 7361 if (likely(!event->filter) || filter_match_preds(event->filter, record)) 7362 return 1; 7363 return 0; 7364 } 7365 7366 static int perf_tp_event_match(struct perf_event *event, 7367 struct perf_sample_data *data, 7368 struct pt_regs *regs) 7369 { 7370 if (event->hw.state & PERF_HES_STOPPED) 7371 return 0; 7372 /* 7373 * All tracepoints are from kernel-space. 7374 */ 7375 if (event->attr.exclude_kernel) 7376 return 0; 7377 7378 if (!perf_tp_filter_match(event, data)) 7379 return 0; 7380 7381 return 1; 7382 } 7383 7384 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx, 7385 struct trace_event_call *call, u64 count, 7386 struct pt_regs *regs, struct hlist_head *head, 7387 struct task_struct *task) 7388 { 7389 struct bpf_prog *prog = call->prog; 7390 7391 if (prog) { 7392 *(struct pt_regs **)raw_data = regs; 7393 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) { 7394 perf_swevent_put_recursion_context(rctx); 7395 return; 7396 } 7397 } 7398 perf_tp_event(call->event.type, count, raw_data, size, regs, head, 7399 rctx, task); 7400 } 7401 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit); 7402 7403 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size, 7404 struct pt_regs *regs, struct hlist_head *head, int rctx, 7405 struct task_struct *task) 7406 { 7407 struct perf_sample_data data; 7408 struct perf_event *event; 7409 7410 struct perf_raw_record raw = { 7411 .size = entry_size, 7412 .data = record, 7413 }; 7414 7415 perf_sample_data_init(&data, 0, 0); 7416 data.raw = &raw; 7417 7418 perf_trace_buf_update(record, event_type); 7419 7420 hlist_for_each_entry_rcu(event, head, hlist_entry) { 7421 if (perf_tp_event_match(event, &data, regs)) 7422 perf_swevent_event(event, count, &data, regs); 7423 } 7424 7425 /* 7426 * If we got specified a target task, also iterate its context and 7427 * deliver this event there too. 7428 */ 7429 if (task && task != current) { 7430 struct perf_event_context *ctx; 7431 struct trace_entry *entry = record; 7432 7433 rcu_read_lock(); 7434 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]); 7435 if (!ctx) 7436 goto unlock; 7437 7438 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 7439 if (event->attr.type != PERF_TYPE_TRACEPOINT) 7440 continue; 7441 if (event->attr.config != entry->type) 7442 continue; 7443 if (perf_tp_event_match(event, &data, regs)) 7444 perf_swevent_event(event, count, &data, regs); 7445 } 7446 unlock: 7447 rcu_read_unlock(); 7448 } 7449 7450 perf_swevent_put_recursion_context(rctx); 7451 } 7452 EXPORT_SYMBOL_GPL(perf_tp_event); 7453 7454 static void tp_perf_event_destroy(struct perf_event *event) 7455 { 7456 perf_trace_destroy(event); 7457 } 7458 7459 static int perf_tp_event_init(struct perf_event *event) 7460 { 7461 int err; 7462 7463 if (event->attr.type != PERF_TYPE_TRACEPOINT) 7464 return -ENOENT; 7465 7466 /* 7467 * no branch sampling for tracepoint events 7468 */ 7469 if (has_branch_stack(event)) 7470 return -EOPNOTSUPP; 7471 7472 err = perf_trace_init(event); 7473 if (err) 7474 return err; 7475 7476 event->destroy = tp_perf_event_destroy; 7477 7478 return 0; 7479 } 7480 7481 static struct pmu perf_tracepoint = { 7482 .task_ctx_nr = perf_sw_context, 7483 7484 .event_init = perf_tp_event_init, 7485 .add = perf_trace_add, 7486 .del = perf_trace_del, 7487 .start = perf_swevent_start, 7488 .stop = perf_swevent_stop, 7489 .read = perf_swevent_read, 7490 }; 7491 7492 static inline void perf_tp_register(void) 7493 { 7494 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT); 7495 } 7496 7497 static void perf_event_free_filter(struct perf_event *event) 7498 { 7499 ftrace_profile_free_filter(event); 7500 } 7501 7502 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) 7503 { 7504 bool is_kprobe, is_tracepoint; 7505 struct bpf_prog *prog; 7506 7507 if (event->attr.type != PERF_TYPE_TRACEPOINT) 7508 return -EINVAL; 7509 7510 if (event->tp_event->prog) 7511 return -EEXIST; 7512 7513 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE; 7514 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT; 7515 if (!is_kprobe && !is_tracepoint) 7516 /* bpf programs can only be attached to u/kprobe or tracepoint */ 7517 return -EINVAL; 7518 7519 prog = bpf_prog_get(prog_fd); 7520 if (IS_ERR(prog)) 7521 return PTR_ERR(prog); 7522 7523 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) || 7524 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT)) { 7525 /* valid fd, but invalid bpf program type */ 7526 bpf_prog_put(prog); 7527 return -EINVAL; 7528 } 7529 7530 if (is_tracepoint) { 7531 int off = trace_event_get_offsets(event->tp_event); 7532 7533 if (prog->aux->max_ctx_offset > off) { 7534 bpf_prog_put(prog); 7535 return -EACCES; 7536 } 7537 } 7538 event->tp_event->prog = prog; 7539 7540 return 0; 7541 } 7542 7543 static void perf_event_free_bpf_prog(struct perf_event *event) 7544 { 7545 struct bpf_prog *prog; 7546 7547 if (!event->tp_event) 7548 return; 7549 7550 prog = event->tp_event->prog; 7551 if (prog) { 7552 event->tp_event->prog = NULL; 7553 bpf_prog_put_rcu(prog); 7554 } 7555 } 7556 7557 #else 7558 7559 static inline void perf_tp_register(void) 7560 { 7561 } 7562 7563 static void perf_event_free_filter(struct perf_event *event) 7564 { 7565 } 7566 7567 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) 7568 { 7569 return -ENOENT; 7570 } 7571 7572 static void perf_event_free_bpf_prog(struct perf_event *event) 7573 { 7574 } 7575 #endif /* CONFIG_EVENT_TRACING */ 7576 7577 #ifdef CONFIG_HAVE_HW_BREAKPOINT 7578 void perf_bp_event(struct perf_event *bp, void *data) 7579 { 7580 struct perf_sample_data sample; 7581 struct pt_regs *regs = data; 7582 7583 perf_sample_data_init(&sample, bp->attr.bp_addr, 0); 7584 7585 if (!bp->hw.state && !perf_exclude_event(bp, regs)) 7586 perf_swevent_event(bp, 1, &sample, regs); 7587 } 7588 #endif 7589 7590 /* 7591 * Allocate a new address filter 7592 */ 7593 static struct perf_addr_filter * 7594 perf_addr_filter_new(struct perf_event *event, struct list_head *filters) 7595 { 7596 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu); 7597 struct perf_addr_filter *filter; 7598 7599 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node); 7600 if (!filter) 7601 return NULL; 7602 7603 INIT_LIST_HEAD(&filter->entry); 7604 list_add_tail(&filter->entry, filters); 7605 7606 return filter; 7607 } 7608 7609 static void free_filters_list(struct list_head *filters) 7610 { 7611 struct perf_addr_filter *filter, *iter; 7612 7613 list_for_each_entry_safe(filter, iter, filters, entry) { 7614 if (filter->inode) 7615 iput(filter->inode); 7616 list_del(&filter->entry); 7617 kfree(filter); 7618 } 7619 } 7620 7621 /* 7622 * Free existing address filters and optionally install new ones 7623 */ 7624 static void perf_addr_filters_splice(struct perf_event *event, 7625 struct list_head *head) 7626 { 7627 unsigned long flags; 7628 LIST_HEAD(list); 7629 7630 if (!has_addr_filter(event)) 7631 return; 7632 7633 /* don't bother with children, they don't have their own filters */ 7634 if (event->parent) 7635 return; 7636 7637 raw_spin_lock_irqsave(&event->addr_filters.lock, flags); 7638 7639 list_splice_init(&event->addr_filters.list, &list); 7640 if (head) 7641 list_splice(head, &event->addr_filters.list); 7642 7643 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags); 7644 7645 free_filters_list(&list); 7646 } 7647 7648 /* 7649 * Scan through mm's vmas and see if one of them matches the 7650 * @filter; if so, adjust filter's address range. 7651 * Called with mm::mmap_sem down for reading. 7652 */ 7653 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter, 7654 struct mm_struct *mm) 7655 { 7656 struct vm_area_struct *vma; 7657 7658 for (vma = mm->mmap; vma; vma = vma->vm_next) { 7659 struct file *file = vma->vm_file; 7660 unsigned long off = vma->vm_pgoff << PAGE_SHIFT; 7661 unsigned long vma_size = vma->vm_end - vma->vm_start; 7662 7663 if (!file) 7664 continue; 7665 7666 if (!perf_addr_filter_match(filter, file, off, vma_size)) 7667 continue; 7668 7669 return vma->vm_start; 7670 } 7671 7672 return 0; 7673 } 7674 7675 /* 7676 * Update event's address range filters based on the 7677 * task's existing mappings, if any. 7678 */ 7679 static void perf_event_addr_filters_apply(struct perf_event *event) 7680 { 7681 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 7682 struct task_struct *task = READ_ONCE(event->ctx->task); 7683 struct perf_addr_filter *filter; 7684 struct mm_struct *mm = NULL; 7685 unsigned int count = 0; 7686 unsigned long flags; 7687 7688 /* 7689 * We may observe TASK_TOMBSTONE, which means that the event tear-down 7690 * will stop on the parent's child_mutex that our caller is also holding 7691 */ 7692 if (task == TASK_TOMBSTONE) 7693 return; 7694 7695 mm = get_task_mm(event->ctx->task); 7696 if (!mm) 7697 goto restart; 7698 7699 down_read(&mm->mmap_sem); 7700 7701 raw_spin_lock_irqsave(&ifh->lock, flags); 7702 list_for_each_entry(filter, &ifh->list, entry) { 7703 event->addr_filters_offs[count] = 0; 7704 7705 if (perf_addr_filter_needs_mmap(filter)) 7706 event->addr_filters_offs[count] = 7707 perf_addr_filter_apply(filter, mm); 7708 7709 count++; 7710 } 7711 7712 event->addr_filters_gen++; 7713 raw_spin_unlock_irqrestore(&ifh->lock, flags); 7714 7715 up_read(&mm->mmap_sem); 7716 7717 mmput(mm); 7718 7719 restart: 7720 perf_event_restart(event); 7721 } 7722 7723 /* 7724 * Address range filtering: limiting the data to certain 7725 * instruction address ranges. Filters are ioctl()ed to us from 7726 * userspace as ascii strings. 7727 * 7728 * Filter string format: 7729 * 7730 * ACTION RANGE_SPEC 7731 * where ACTION is one of the 7732 * * "filter": limit the trace to this region 7733 * * "start": start tracing from this address 7734 * * "stop": stop tracing at this address/region; 7735 * RANGE_SPEC is 7736 * * for kernel addresses: <start address>[/<size>] 7737 * * for object files: <start address>[/<size>]@</path/to/object/file> 7738 * 7739 * if <size> is not specified, the range is treated as a single address. 7740 */ 7741 enum { 7742 IF_ACT_FILTER, 7743 IF_ACT_START, 7744 IF_ACT_STOP, 7745 IF_SRC_FILE, 7746 IF_SRC_KERNEL, 7747 IF_SRC_FILEADDR, 7748 IF_SRC_KERNELADDR, 7749 }; 7750 7751 enum { 7752 IF_STATE_ACTION = 0, 7753 IF_STATE_SOURCE, 7754 IF_STATE_END, 7755 }; 7756 7757 static const match_table_t if_tokens = { 7758 { IF_ACT_FILTER, "filter" }, 7759 { IF_ACT_START, "start" }, 7760 { IF_ACT_STOP, "stop" }, 7761 { IF_SRC_FILE, "%u/%u@%s" }, 7762 { IF_SRC_KERNEL, "%u/%u" }, 7763 { IF_SRC_FILEADDR, "%u@%s" }, 7764 { IF_SRC_KERNELADDR, "%u" }, 7765 }; 7766 7767 /* 7768 * Address filter string parser 7769 */ 7770 static int 7771 perf_event_parse_addr_filter(struct perf_event *event, char *fstr, 7772 struct list_head *filters) 7773 { 7774 struct perf_addr_filter *filter = NULL; 7775 char *start, *orig, *filename = NULL; 7776 struct path path; 7777 substring_t args[MAX_OPT_ARGS]; 7778 int state = IF_STATE_ACTION, token; 7779 unsigned int kernel = 0; 7780 int ret = -EINVAL; 7781 7782 orig = fstr = kstrdup(fstr, GFP_KERNEL); 7783 if (!fstr) 7784 return -ENOMEM; 7785 7786 while ((start = strsep(&fstr, " ,\n")) != NULL) { 7787 ret = -EINVAL; 7788 7789 if (!*start) 7790 continue; 7791 7792 /* filter definition begins */ 7793 if (state == IF_STATE_ACTION) { 7794 filter = perf_addr_filter_new(event, filters); 7795 if (!filter) 7796 goto fail; 7797 } 7798 7799 token = match_token(start, if_tokens, args); 7800 switch (token) { 7801 case IF_ACT_FILTER: 7802 case IF_ACT_START: 7803 filter->filter = 1; 7804 7805 case IF_ACT_STOP: 7806 if (state != IF_STATE_ACTION) 7807 goto fail; 7808 7809 state = IF_STATE_SOURCE; 7810 break; 7811 7812 case IF_SRC_KERNELADDR: 7813 case IF_SRC_KERNEL: 7814 kernel = 1; 7815 7816 case IF_SRC_FILEADDR: 7817 case IF_SRC_FILE: 7818 if (state != IF_STATE_SOURCE) 7819 goto fail; 7820 7821 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL) 7822 filter->range = 1; 7823 7824 *args[0].to = 0; 7825 ret = kstrtoul(args[0].from, 0, &filter->offset); 7826 if (ret) 7827 goto fail; 7828 7829 if (filter->range) { 7830 *args[1].to = 0; 7831 ret = kstrtoul(args[1].from, 0, &filter->size); 7832 if (ret) 7833 goto fail; 7834 } 7835 7836 if (token == IF_SRC_FILE) { 7837 filename = match_strdup(&args[2]); 7838 if (!filename) { 7839 ret = -ENOMEM; 7840 goto fail; 7841 } 7842 } 7843 7844 state = IF_STATE_END; 7845 break; 7846 7847 default: 7848 goto fail; 7849 } 7850 7851 /* 7852 * Filter definition is fully parsed, validate and install it. 7853 * Make sure that it doesn't contradict itself or the event's 7854 * attribute. 7855 */ 7856 if (state == IF_STATE_END) { 7857 if (kernel && event->attr.exclude_kernel) 7858 goto fail; 7859 7860 if (!kernel) { 7861 if (!filename) 7862 goto fail; 7863 7864 /* look up the path and grab its inode */ 7865 ret = kern_path(filename, LOOKUP_FOLLOW, &path); 7866 if (ret) 7867 goto fail_free_name; 7868 7869 filter->inode = igrab(d_inode(path.dentry)); 7870 path_put(&path); 7871 kfree(filename); 7872 filename = NULL; 7873 7874 ret = -EINVAL; 7875 if (!filter->inode || 7876 !S_ISREG(filter->inode->i_mode)) 7877 /* free_filters_list() will iput() */ 7878 goto fail; 7879 } 7880 7881 /* ready to consume more filters */ 7882 state = IF_STATE_ACTION; 7883 filter = NULL; 7884 } 7885 } 7886 7887 if (state != IF_STATE_ACTION) 7888 goto fail; 7889 7890 kfree(orig); 7891 7892 return 0; 7893 7894 fail_free_name: 7895 kfree(filename); 7896 fail: 7897 free_filters_list(filters); 7898 kfree(orig); 7899 7900 return ret; 7901 } 7902 7903 static int 7904 perf_event_set_addr_filter(struct perf_event *event, char *filter_str) 7905 { 7906 LIST_HEAD(filters); 7907 int ret; 7908 7909 /* 7910 * Since this is called in perf_ioctl() path, we're already holding 7911 * ctx::mutex. 7912 */ 7913 lockdep_assert_held(&event->ctx->mutex); 7914 7915 if (WARN_ON_ONCE(event->parent)) 7916 return -EINVAL; 7917 7918 /* 7919 * For now, we only support filtering in per-task events; doing so 7920 * for CPU-wide events requires additional context switching trickery, 7921 * since same object code will be mapped at different virtual 7922 * addresses in different processes. 7923 */ 7924 if (!event->ctx->task) 7925 return -EOPNOTSUPP; 7926 7927 ret = perf_event_parse_addr_filter(event, filter_str, &filters); 7928 if (ret) 7929 return ret; 7930 7931 ret = event->pmu->addr_filters_validate(&filters); 7932 if (ret) { 7933 free_filters_list(&filters); 7934 return ret; 7935 } 7936 7937 /* remove existing filters, if any */ 7938 perf_addr_filters_splice(event, &filters); 7939 7940 /* install new filters */ 7941 perf_event_for_each_child(event, perf_event_addr_filters_apply); 7942 7943 return ret; 7944 } 7945 7946 static int perf_event_set_filter(struct perf_event *event, void __user *arg) 7947 { 7948 char *filter_str; 7949 int ret = -EINVAL; 7950 7951 if ((event->attr.type != PERF_TYPE_TRACEPOINT || 7952 !IS_ENABLED(CONFIG_EVENT_TRACING)) && 7953 !has_addr_filter(event)) 7954 return -EINVAL; 7955 7956 filter_str = strndup_user(arg, PAGE_SIZE); 7957 if (IS_ERR(filter_str)) 7958 return PTR_ERR(filter_str); 7959 7960 if (IS_ENABLED(CONFIG_EVENT_TRACING) && 7961 event->attr.type == PERF_TYPE_TRACEPOINT) 7962 ret = ftrace_profile_set_filter(event, event->attr.config, 7963 filter_str); 7964 else if (has_addr_filter(event)) 7965 ret = perf_event_set_addr_filter(event, filter_str); 7966 7967 kfree(filter_str); 7968 return ret; 7969 } 7970 7971 /* 7972 * hrtimer based swevent callback 7973 */ 7974 7975 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer) 7976 { 7977 enum hrtimer_restart ret = HRTIMER_RESTART; 7978 struct perf_sample_data data; 7979 struct pt_regs *regs; 7980 struct perf_event *event; 7981 u64 period; 7982 7983 event = container_of(hrtimer, struct perf_event, hw.hrtimer); 7984 7985 if (event->state != PERF_EVENT_STATE_ACTIVE) 7986 return HRTIMER_NORESTART; 7987 7988 event->pmu->read(event); 7989 7990 perf_sample_data_init(&data, 0, event->hw.last_period); 7991 regs = get_irq_regs(); 7992 7993 if (regs && !perf_exclude_event(event, regs)) { 7994 if (!(event->attr.exclude_idle && is_idle_task(current))) 7995 if (__perf_event_overflow(event, 1, &data, regs)) 7996 ret = HRTIMER_NORESTART; 7997 } 7998 7999 period = max_t(u64, 10000, event->hw.sample_period); 8000 hrtimer_forward_now(hrtimer, ns_to_ktime(period)); 8001 8002 return ret; 8003 } 8004 8005 static void perf_swevent_start_hrtimer(struct perf_event *event) 8006 { 8007 struct hw_perf_event *hwc = &event->hw; 8008 s64 period; 8009 8010 if (!is_sampling_event(event)) 8011 return; 8012 8013 period = local64_read(&hwc->period_left); 8014 if (period) { 8015 if (period < 0) 8016 period = 10000; 8017 8018 local64_set(&hwc->period_left, 0); 8019 } else { 8020 period = max_t(u64, 10000, hwc->sample_period); 8021 } 8022 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period), 8023 HRTIMER_MODE_REL_PINNED); 8024 } 8025 8026 static void perf_swevent_cancel_hrtimer(struct perf_event *event) 8027 { 8028 struct hw_perf_event *hwc = &event->hw; 8029 8030 if (is_sampling_event(event)) { 8031 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer); 8032 local64_set(&hwc->period_left, ktime_to_ns(remaining)); 8033 8034 hrtimer_cancel(&hwc->hrtimer); 8035 } 8036 } 8037 8038 static void perf_swevent_init_hrtimer(struct perf_event *event) 8039 { 8040 struct hw_perf_event *hwc = &event->hw; 8041 8042 if (!is_sampling_event(event)) 8043 return; 8044 8045 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 8046 hwc->hrtimer.function = perf_swevent_hrtimer; 8047 8048 /* 8049 * Since hrtimers have a fixed rate, we can do a static freq->period 8050 * mapping and avoid the whole period adjust feedback stuff. 8051 */ 8052 if (event->attr.freq) { 8053 long freq = event->attr.sample_freq; 8054 8055 event->attr.sample_period = NSEC_PER_SEC / freq; 8056 hwc->sample_period = event->attr.sample_period; 8057 local64_set(&hwc->period_left, hwc->sample_period); 8058 hwc->last_period = hwc->sample_period; 8059 event->attr.freq = 0; 8060 } 8061 } 8062 8063 /* 8064 * Software event: cpu wall time clock 8065 */ 8066 8067 static void cpu_clock_event_update(struct perf_event *event) 8068 { 8069 s64 prev; 8070 u64 now; 8071 8072 now = local_clock(); 8073 prev = local64_xchg(&event->hw.prev_count, now); 8074 local64_add(now - prev, &event->count); 8075 } 8076 8077 static void cpu_clock_event_start(struct perf_event *event, int flags) 8078 { 8079 local64_set(&event->hw.prev_count, local_clock()); 8080 perf_swevent_start_hrtimer(event); 8081 } 8082 8083 static void cpu_clock_event_stop(struct perf_event *event, int flags) 8084 { 8085 perf_swevent_cancel_hrtimer(event); 8086 cpu_clock_event_update(event); 8087 } 8088 8089 static int cpu_clock_event_add(struct perf_event *event, int flags) 8090 { 8091 if (flags & PERF_EF_START) 8092 cpu_clock_event_start(event, flags); 8093 perf_event_update_userpage(event); 8094 8095 return 0; 8096 } 8097 8098 static void cpu_clock_event_del(struct perf_event *event, int flags) 8099 { 8100 cpu_clock_event_stop(event, flags); 8101 } 8102 8103 static void cpu_clock_event_read(struct perf_event *event) 8104 { 8105 cpu_clock_event_update(event); 8106 } 8107 8108 static int cpu_clock_event_init(struct perf_event *event) 8109 { 8110 if (event->attr.type != PERF_TYPE_SOFTWARE) 8111 return -ENOENT; 8112 8113 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK) 8114 return -ENOENT; 8115 8116 /* 8117 * no branch sampling for software events 8118 */ 8119 if (has_branch_stack(event)) 8120 return -EOPNOTSUPP; 8121 8122 perf_swevent_init_hrtimer(event); 8123 8124 return 0; 8125 } 8126 8127 static struct pmu perf_cpu_clock = { 8128 .task_ctx_nr = perf_sw_context, 8129 8130 .capabilities = PERF_PMU_CAP_NO_NMI, 8131 8132 .event_init = cpu_clock_event_init, 8133 .add = cpu_clock_event_add, 8134 .del = cpu_clock_event_del, 8135 .start = cpu_clock_event_start, 8136 .stop = cpu_clock_event_stop, 8137 .read = cpu_clock_event_read, 8138 }; 8139 8140 /* 8141 * Software event: task time clock 8142 */ 8143 8144 static void task_clock_event_update(struct perf_event *event, u64 now) 8145 { 8146 u64 prev; 8147 s64 delta; 8148 8149 prev = local64_xchg(&event->hw.prev_count, now); 8150 delta = now - prev; 8151 local64_add(delta, &event->count); 8152 } 8153 8154 static void task_clock_event_start(struct perf_event *event, int flags) 8155 { 8156 local64_set(&event->hw.prev_count, event->ctx->time); 8157 perf_swevent_start_hrtimer(event); 8158 } 8159 8160 static void task_clock_event_stop(struct perf_event *event, int flags) 8161 { 8162 perf_swevent_cancel_hrtimer(event); 8163 task_clock_event_update(event, event->ctx->time); 8164 } 8165 8166 static int task_clock_event_add(struct perf_event *event, int flags) 8167 { 8168 if (flags & PERF_EF_START) 8169 task_clock_event_start(event, flags); 8170 perf_event_update_userpage(event); 8171 8172 return 0; 8173 } 8174 8175 static void task_clock_event_del(struct perf_event *event, int flags) 8176 { 8177 task_clock_event_stop(event, PERF_EF_UPDATE); 8178 } 8179 8180 static void task_clock_event_read(struct perf_event *event) 8181 { 8182 u64 now = perf_clock(); 8183 u64 delta = now - event->ctx->timestamp; 8184 u64 time = event->ctx->time + delta; 8185 8186 task_clock_event_update(event, time); 8187 } 8188 8189 static int task_clock_event_init(struct perf_event *event) 8190 { 8191 if (event->attr.type != PERF_TYPE_SOFTWARE) 8192 return -ENOENT; 8193 8194 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK) 8195 return -ENOENT; 8196 8197 /* 8198 * no branch sampling for software events 8199 */ 8200 if (has_branch_stack(event)) 8201 return -EOPNOTSUPP; 8202 8203 perf_swevent_init_hrtimer(event); 8204 8205 return 0; 8206 } 8207 8208 static struct pmu perf_task_clock = { 8209 .task_ctx_nr = perf_sw_context, 8210 8211 .capabilities = PERF_PMU_CAP_NO_NMI, 8212 8213 .event_init = task_clock_event_init, 8214 .add = task_clock_event_add, 8215 .del = task_clock_event_del, 8216 .start = task_clock_event_start, 8217 .stop = task_clock_event_stop, 8218 .read = task_clock_event_read, 8219 }; 8220 8221 static void perf_pmu_nop_void(struct pmu *pmu) 8222 { 8223 } 8224 8225 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags) 8226 { 8227 } 8228 8229 static int perf_pmu_nop_int(struct pmu *pmu) 8230 { 8231 return 0; 8232 } 8233 8234 static DEFINE_PER_CPU(unsigned int, nop_txn_flags); 8235 8236 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags) 8237 { 8238 __this_cpu_write(nop_txn_flags, flags); 8239 8240 if (flags & ~PERF_PMU_TXN_ADD) 8241 return; 8242 8243 perf_pmu_disable(pmu); 8244 } 8245 8246 static int perf_pmu_commit_txn(struct pmu *pmu) 8247 { 8248 unsigned int flags = __this_cpu_read(nop_txn_flags); 8249 8250 __this_cpu_write(nop_txn_flags, 0); 8251 8252 if (flags & ~PERF_PMU_TXN_ADD) 8253 return 0; 8254 8255 perf_pmu_enable(pmu); 8256 return 0; 8257 } 8258 8259 static void perf_pmu_cancel_txn(struct pmu *pmu) 8260 { 8261 unsigned int flags = __this_cpu_read(nop_txn_flags); 8262 8263 __this_cpu_write(nop_txn_flags, 0); 8264 8265 if (flags & ~PERF_PMU_TXN_ADD) 8266 return; 8267 8268 perf_pmu_enable(pmu); 8269 } 8270 8271 static int perf_event_idx_default(struct perf_event *event) 8272 { 8273 return 0; 8274 } 8275 8276 /* 8277 * Ensures all contexts with the same task_ctx_nr have the same 8278 * pmu_cpu_context too. 8279 */ 8280 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn) 8281 { 8282 struct pmu *pmu; 8283 8284 if (ctxn < 0) 8285 return NULL; 8286 8287 list_for_each_entry(pmu, &pmus, entry) { 8288 if (pmu->task_ctx_nr == ctxn) 8289 return pmu->pmu_cpu_context; 8290 } 8291 8292 return NULL; 8293 } 8294 8295 static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu) 8296 { 8297 int cpu; 8298 8299 for_each_possible_cpu(cpu) { 8300 struct perf_cpu_context *cpuctx; 8301 8302 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 8303 8304 if (cpuctx->unique_pmu == old_pmu) 8305 cpuctx->unique_pmu = pmu; 8306 } 8307 } 8308 8309 static void free_pmu_context(struct pmu *pmu) 8310 { 8311 struct pmu *i; 8312 8313 mutex_lock(&pmus_lock); 8314 /* 8315 * Like a real lame refcount. 8316 */ 8317 list_for_each_entry(i, &pmus, entry) { 8318 if (i->pmu_cpu_context == pmu->pmu_cpu_context) { 8319 update_pmu_context(i, pmu); 8320 goto out; 8321 } 8322 } 8323 8324 free_percpu(pmu->pmu_cpu_context); 8325 out: 8326 mutex_unlock(&pmus_lock); 8327 } 8328 8329 /* 8330 * Let userspace know that this PMU supports address range filtering: 8331 */ 8332 static ssize_t nr_addr_filters_show(struct device *dev, 8333 struct device_attribute *attr, 8334 char *page) 8335 { 8336 struct pmu *pmu = dev_get_drvdata(dev); 8337 8338 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters); 8339 } 8340 DEVICE_ATTR_RO(nr_addr_filters); 8341 8342 static struct idr pmu_idr; 8343 8344 static ssize_t 8345 type_show(struct device *dev, struct device_attribute *attr, char *page) 8346 { 8347 struct pmu *pmu = dev_get_drvdata(dev); 8348 8349 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type); 8350 } 8351 static DEVICE_ATTR_RO(type); 8352 8353 static ssize_t 8354 perf_event_mux_interval_ms_show(struct device *dev, 8355 struct device_attribute *attr, 8356 char *page) 8357 { 8358 struct pmu *pmu = dev_get_drvdata(dev); 8359 8360 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms); 8361 } 8362 8363 static DEFINE_MUTEX(mux_interval_mutex); 8364 8365 static ssize_t 8366 perf_event_mux_interval_ms_store(struct device *dev, 8367 struct device_attribute *attr, 8368 const char *buf, size_t count) 8369 { 8370 struct pmu *pmu = dev_get_drvdata(dev); 8371 int timer, cpu, ret; 8372 8373 ret = kstrtoint(buf, 0, &timer); 8374 if (ret) 8375 return ret; 8376 8377 if (timer < 1) 8378 return -EINVAL; 8379 8380 /* same value, noting to do */ 8381 if (timer == pmu->hrtimer_interval_ms) 8382 return count; 8383 8384 mutex_lock(&mux_interval_mutex); 8385 pmu->hrtimer_interval_ms = timer; 8386 8387 /* update all cpuctx for this PMU */ 8388 get_online_cpus(); 8389 for_each_online_cpu(cpu) { 8390 struct perf_cpu_context *cpuctx; 8391 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 8392 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer); 8393 8394 cpu_function_call(cpu, 8395 (remote_function_f)perf_mux_hrtimer_restart, cpuctx); 8396 } 8397 put_online_cpus(); 8398 mutex_unlock(&mux_interval_mutex); 8399 8400 return count; 8401 } 8402 static DEVICE_ATTR_RW(perf_event_mux_interval_ms); 8403 8404 static struct attribute *pmu_dev_attrs[] = { 8405 &dev_attr_type.attr, 8406 &dev_attr_perf_event_mux_interval_ms.attr, 8407 NULL, 8408 }; 8409 ATTRIBUTE_GROUPS(pmu_dev); 8410 8411 static int pmu_bus_running; 8412 static struct bus_type pmu_bus = { 8413 .name = "event_source", 8414 .dev_groups = pmu_dev_groups, 8415 }; 8416 8417 static void pmu_dev_release(struct device *dev) 8418 { 8419 kfree(dev); 8420 } 8421 8422 static int pmu_dev_alloc(struct pmu *pmu) 8423 { 8424 int ret = -ENOMEM; 8425 8426 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL); 8427 if (!pmu->dev) 8428 goto out; 8429 8430 pmu->dev->groups = pmu->attr_groups; 8431 device_initialize(pmu->dev); 8432 ret = dev_set_name(pmu->dev, "%s", pmu->name); 8433 if (ret) 8434 goto free_dev; 8435 8436 dev_set_drvdata(pmu->dev, pmu); 8437 pmu->dev->bus = &pmu_bus; 8438 pmu->dev->release = pmu_dev_release; 8439 ret = device_add(pmu->dev); 8440 if (ret) 8441 goto free_dev; 8442 8443 /* For PMUs with address filters, throw in an extra attribute: */ 8444 if (pmu->nr_addr_filters) 8445 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters); 8446 8447 if (ret) 8448 goto del_dev; 8449 8450 out: 8451 return ret; 8452 8453 del_dev: 8454 device_del(pmu->dev); 8455 8456 free_dev: 8457 put_device(pmu->dev); 8458 goto out; 8459 } 8460 8461 static struct lock_class_key cpuctx_mutex; 8462 static struct lock_class_key cpuctx_lock; 8463 8464 int perf_pmu_register(struct pmu *pmu, const char *name, int type) 8465 { 8466 int cpu, ret; 8467 8468 mutex_lock(&pmus_lock); 8469 ret = -ENOMEM; 8470 pmu->pmu_disable_count = alloc_percpu(int); 8471 if (!pmu->pmu_disable_count) 8472 goto unlock; 8473 8474 pmu->type = -1; 8475 if (!name) 8476 goto skip_type; 8477 pmu->name = name; 8478 8479 if (type < 0) { 8480 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL); 8481 if (type < 0) { 8482 ret = type; 8483 goto free_pdc; 8484 } 8485 } 8486 pmu->type = type; 8487 8488 if (pmu_bus_running) { 8489 ret = pmu_dev_alloc(pmu); 8490 if (ret) 8491 goto free_idr; 8492 } 8493 8494 skip_type: 8495 if (pmu->task_ctx_nr == perf_hw_context) { 8496 static int hw_context_taken = 0; 8497 8498 /* 8499 * Other than systems with heterogeneous CPUs, it never makes 8500 * sense for two PMUs to share perf_hw_context. PMUs which are 8501 * uncore must use perf_invalid_context. 8502 */ 8503 if (WARN_ON_ONCE(hw_context_taken && 8504 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS))) 8505 pmu->task_ctx_nr = perf_invalid_context; 8506 8507 hw_context_taken = 1; 8508 } 8509 8510 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr); 8511 if (pmu->pmu_cpu_context) 8512 goto got_cpu_context; 8513 8514 ret = -ENOMEM; 8515 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context); 8516 if (!pmu->pmu_cpu_context) 8517 goto free_dev; 8518 8519 for_each_possible_cpu(cpu) { 8520 struct perf_cpu_context *cpuctx; 8521 8522 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 8523 __perf_event_init_context(&cpuctx->ctx); 8524 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex); 8525 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock); 8526 cpuctx->ctx.pmu = pmu; 8527 8528 __perf_mux_hrtimer_init(cpuctx, cpu); 8529 8530 cpuctx->unique_pmu = pmu; 8531 } 8532 8533 got_cpu_context: 8534 if (!pmu->start_txn) { 8535 if (pmu->pmu_enable) { 8536 /* 8537 * If we have pmu_enable/pmu_disable calls, install 8538 * transaction stubs that use that to try and batch 8539 * hardware accesses. 8540 */ 8541 pmu->start_txn = perf_pmu_start_txn; 8542 pmu->commit_txn = perf_pmu_commit_txn; 8543 pmu->cancel_txn = perf_pmu_cancel_txn; 8544 } else { 8545 pmu->start_txn = perf_pmu_nop_txn; 8546 pmu->commit_txn = perf_pmu_nop_int; 8547 pmu->cancel_txn = perf_pmu_nop_void; 8548 } 8549 } 8550 8551 if (!pmu->pmu_enable) { 8552 pmu->pmu_enable = perf_pmu_nop_void; 8553 pmu->pmu_disable = perf_pmu_nop_void; 8554 } 8555 8556 if (!pmu->event_idx) 8557 pmu->event_idx = perf_event_idx_default; 8558 8559 list_add_rcu(&pmu->entry, &pmus); 8560 atomic_set(&pmu->exclusive_cnt, 0); 8561 ret = 0; 8562 unlock: 8563 mutex_unlock(&pmus_lock); 8564 8565 return ret; 8566 8567 free_dev: 8568 device_del(pmu->dev); 8569 put_device(pmu->dev); 8570 8571 free_idr: 8572 if (pmu->type >= PERF_TYPE_MAX) 8573 idr_remove(&pmu_idr, pmu->type); 8574 8575 free_pdc: 8576 free_percpu(pmu->pmu_disable_count); 8577 goto unlock; 8578 } 8579 EXPORT_SYMBOL_GPL(perf_pmu_register); 8580 8581 void perf_pmu_unregister(struct pmu *pmu) 8582 { 8583 mutex_lock(&pmus_lock); 8584 list_del_rcu(&pmu->entry); 8585 mutex_unlock(&pmus_lock); 8586 8587 /* 8588 * We dereference the pmu list under both SRCU and regular RCU, so 8589 * synchronize against both of those. 8590 */ 8591 synchronize_srcu(&pmus_srcu); 8592 synchronize_rcu(); 8593 8594 free_percpu(pmu->pmu_disable_count); 8595 if (pmu->type >= PERF_TYPE_MAX) 8596 idr_remove(&pmu_idr, pmu->type); 8597 if (pmu->nr_addr_filters) 8598 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters); 8599 device_del(pmu->dev); 8600 put_device(pmu->dev); 8601 free_pmu_context(pmu); 8602 } 8603 EXPORT_SYMBOL_GPL(perf_pmu_unregister); 8604 8605 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event) 8606 { 8607 struct perf_event_context *ctx = NULL; 8608 int ret; 8609 8610 if (!try_module_get(pmu->module)) 8611 return -ENODEV; 8612 8613 if (event->group_leader != event) { 8614 /* 8615 * This ctx->mutex can nest when we're called through 8616 * inheritance. See the perf_event_ctx_lock_nested() comment. 8617 */ 8618 ctx = perf_event_ctx_lock_nested(event->group_leader, 8619 SINGLE_DEPTH_NESTING); 8620 BUG_ON(!ctx); 8621 } 8622 8623 event->pmu = pmu; 8624 ret = pmu->event_init(event); 8625 8626 if (ctx) 8627 perf_event_ctx_unlock(event->group_leader, ctx); 8628 8629 if (ret) 8630 module_put(pmu->module); 8631 8632 return ret; 8633 } 8634 8635 static struct pmu *perf_init_event(struct perf_event *event) 8636 { 8637 struct pmu *pmu = NULL; 8638 int idx; 8639 int ret; 8640 8641 idx = srcu_read_lock(&pmus_srcu); 8642 8643 rcu_read_lock(); 8644 pmu = idr_find(&pmu_idr, event->attr.type); 8645 rcu_read_unlock(); 8646 if (pmu) { 8647 ret = perf_try_init_event(pmu, event); 8648 if (ret) 8649 pmu = ERR_PTR(ret); 8650 goto unlock; 8651 } 8652 8653 list_for_each_entry_rcu(pmu, &pmus, entry) { 8654 ret = perf_try_init_event(pmu, event); 8655 if (!ret) 8656 goto unlock; 8657 8658 if (ret != -ENOENT) { 8659 pmu = ERR_PTR(ret); 8660 goto unlock; 8661 } 8662 } 8663 pmu = ERR_PTR(-ENOENT); 8664 unlock: 8665 srcu_read_unlock(&pmus_srcu, idx); 8666 8667 return pmu; 8668 } 8669 8670 static void account_event_cpu(struct perf_event *event, int cpu) 8671 { 8672 if (event->parent) 8673 return; 8674 8675 if (is_cgroup_event(event)) 8676 atomic_inc(&per_cpu(perf_cgroup_events, cpu)); 8677 } 8678 8679 /* Freq events need the tick to stay alive (see perf_event_task_tick). */ 8680 static void account_freq_event_nohz(void) 8681 { 8682 #ifdef CONFIG_NO_HZ_FULL 8683 /* Lock so we don't race with concurrent unaccount */ 8684 spin_lock(&nr_freq_lock); 8685 if (atomic_inc_return(&nr_freq_events) == 1) 8686 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS); 8687 spin_unlock(&nr_freq_lock); 8688 #endif 8689 } 8690 8691 static void account_freq_event(void) 8692 { 8693 if (tick_nohz_full_enabled()) 8694 account_freq_event_nohz(); 8695 else 8696 atomic_inc(&nr_freq_events); 8697 } 8698 8699 8700 static void account_event(struct perf_event *event) 8701 { 8702 bool inc = false; 8703 8704 if (event->parent) 8705 return; 8706 8707 if (event->attach_state & PERF_ATTACH_TASK) 8708 inc = true; 8709 if (event->attr.mmap || event->attr.mmap_data) 8710 atomic_inc(&nr_mmap_events); 8711 if (event->attr.comm) 8712 atomic_inc(&nr_comm_events); 8713 if (event->attr.task) 8714 atomic_inc(&nr_task_events); 8715 if (event->attr.freq) 8716 account_freq_event(); 8717 if (event->attr.context_switch) { 8718 atomic_inc(&nr_switch_events); 8719 inc = true; 8720 } 8721 if (has_branch_stack(event)) 8722 inc = true; 8723 if (is_cgroup_event(event)) 8724 inc = true; 8725 8726 if (inc) { 8727 if (atomic_inc_not_zero(&perf_sched_count)) 8728 goto enabled; 8729 8730 mutex_lock(&perf_sched_mutex); 8731 if (!atomic_read(&perf_sched_count)) { 8732 static_branch_enable(&perf_sched_events); 8733 /* 8734 * Guarantee that all CPUs observe they key change and 8735 * call the perf scheduling hooks before proceeding to 8736 * install events that need them. 8737 */ 8738 synchronize_sched(); 8739 } 8740 /* 8741 * Now that we have waited for the sync_sched(), allow further 8742 * increments to by-pass the mutex. 8743 */ 8744 atomic_inc(&perf_sched_count); 8745 mutex_unlock(&perf_sched_mutex); 8746 } 8747 enabled: 8748 8749 account_event_cpu(event, event->cpu); 8750 } 8751 8752 /* 8753 * Allocate and initialize a event structure 8754 */ 8755 static struct perf_event * 8756 perf_event_alloc(struct perf_event_attr *attr, int cpu, 8757 struct task_struct *task, 8758 struct perf_event *group_leader, 8759 struct perf_event *parent_event, 8760 perf_overflow_handler_t overflow_handler, 8761 void *context, int cgroup_fd) 8762 { 8763 struct pmu *pmu; 8764 struct perf_event *event; 8765 struct hw_perf_event *hwc; 8766 long err = -EINVAL; 8767 8768 if ((unsigned)cpu >= nr_cpu_ids) { 8769 if (!task || cpu != -1) 8770 return ERR_PTR(-EINVAL); 8771 } 8772 8773 event = kzalloc(sizeof(*event), GFP_KERNEL); 8774 if (!event) 8775 return ERR_PTR(-ENOMEM); 8776 8777 /* 8778 * Single events are their own group leaders, with an 8779 * empty sibling list: 8780 */ 8781 if (!group_leader) 8782 group_leader = event; 8783 8784 mutex_init(&event->child_mutex); 8785 INIT_LIST_HEAD(&event->child_list); 8786 8787 INIT_LIST_HEAD(&event->group_entry); 8788 INIT_LIST_HEAD(&event->event_entry); 8789 INIT_LIST_HEAD(&event->sibling_list); 8790 INIT_LIST_HEAD(&event->rb_entry); 8791 INIT_LIST_HEAD(&event->active_entry); 8792 INIT_LIST_HEAD(&event->addr_filters.list); 8793 INIT_HLIST_NODE(&event->hlist_entry); 8794 8795 8796 init_waitqueue_head(&event->waitq); 8797 init_irq_work(&event->pending, perf_pending_event); 8798 8799 mutex_init(&event->mmap_mutex); 8800 raw_spin_lock_init(&event->addr_filters.lock); 8801 8802 atomic_long_set(&event->refcount, 1); 8803 event->cpu = cpu; 8804 event->attr = *attr; 8805 event->group_leader = group_leader; 8806 event->pmu = NULL; 8807 event->oncpu = -1; 8808 8809 event->parent = parent_event; 8810 8811 event->ns = get_pid_ns(task_active_pid_ns(current)); 8812 event->id = atomic64_inc_return(&perf_event_id); 8813 8814 event->state = PERF_EVENT_STATE_INACTIVE; 8815 8816 if (task) { 8817 event->attach_state = PERF_ATTACH_TASK; 8818 /* 8819 * XXX pmu::event_init needs to know what task to account to 8820 * and we cannot use the ctx information because we need the 8821 * pmu before we get a ctx. 8822 */ 8823 event->hw.target = task; 8824 } 8825 8826 event->clock = &local_clock; 8827 if (parent_event) 8828 event->clock = parent_event->clock; 8829 8830 if (!overflow_handler && parent_event) { 8831 overflow_handler = parent_event->overflow_handler; 8832 context = parent_event->overflow_handler_context; 8833 } 8834 8835 if (overflow_handler) { 8836 event->overflow_handler = overflow_handler; 8837 event->overflow_handler_context = context; 8838 } else if (is_write_backward(event)){ 8839 event->overflow_handler = perf_event_output_backward; 8840 event->overflow_handler_context = NULL; 8841 } else { 8842 event->overflow_handler = perf_event_output_forward; 8843 event->overflow_handler_context = NULL; 8844 } 8845 8846 perf_event__state_init(event); 8847 8848 pmu = NULL; 8849 8850 hwc = &event->hw; 8851 hwc->sample_period = attr->sample_period; 8852 if (attr->freq && attr->sample_freq) 8853 hwc->sample_period = 1; 8854 hwc->last_period = hwc->sample_period; 8855 8856 local64_set(&hwc->period_left, hwc->sample_period); 8857 8858 /* 8859 * we currently do not support PERF_FORMAT_GROUP on inherited events 8860 */ 8861 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP)) 8862 goto err_ns; 8863 8864 if (!has_branch_stack(event)) 8865 event->attr.branch_sample_type = 0; 8866 8867 if (cgroup_fd != -1) { 8868 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader); 8869 if (err) 8870 goto err_ns; 8871 } 8872 8873 pmu = perf_init_event(event); 8874 if (!pmu) 8875 goto err_ns; 8876 else if (IS_ERR(pmu)) { 8877 err = PTR_ERR(pmu); 8878 goto err_ns; 8879 } 8880 8881 err = exclusive_event_init(event); 8882 if (err) 8883 goto err_pmu; 8884 8885 if (has_addr_filter(event)) { 8886 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters, 8887 sizeof(unsigned long), 8888 GFP_KERNEL); 8889 if (!event->addr_filters_offs) 8890 goto err_per_task; 8891 8892 /* force hw sync on the address filters */ 8893 event->addr_filters_gen = 1; 8894 } 8895 8896 if (!event->parent) { 8897 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) { 8898 err = get_callchain_buffers(); 8899 if (err) 8900 goto err_addr_filters; 8901 } 8902 } 8903 8904 /* symmetric to unaccount_event() in _free_event() */ 8905 account_event(event); 8906 8907 return event; 8908 8909 err_addr_filters: 8910 kfree(event->addr_filters_offs); 8911 8912 err_per_task: 8913 exclusive_event_destroy(event); 8914 8915 err_pmu: 8916 if (event->destroy) 8917 event->destroy(event); 8918 module_put(pmu->module); 8919 err_ns: 8920 if (is_cgroup_event(event)) 8921 perf_detach_cgroup(event); 8922 if (event->ns) 8923 put_pid_ns(event->ns); 8924 kfree(event); 8925 8926 return ERR_PTR(err); 8927 } 8928 8929 static int perf_copy_attr(struct perf_event_attr __user *uattr, 8930 struct perf_event_attr *attr) 8931 { 8932 u32 size; 8933 int ret; 8934 8935 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0)) 8936 return -EFAULT; 8937 8938 /* 8939 * zero the full structure, so that a short copy will be nice. 8940 */ 8941 memset(attr, 0, sizeof(*attr)); 8942 8943 ret = get_user(size, &uattr->size); 8944 if (ret) 8945 return ret; 8946 8947 if (size > PAGE_SIZE) /* silly large */ 8948 goto err_size; 8949 8950 if (!size) /* abi compat */ 8951 size = PERF_ATTR_SIZE_VER0; 8952 8953 if (size < PERF_ATTR_SIZE_VER0) 8954 goto err_size; 8955 8956 /* 8957 * If we're handed a bigger struct than we know of, 8958 * ensure all the unknown bits are 0 - i.e. new 8959 * user-space does not rely on any kernel feature 8960 * extensions we dont know about yet. 8961 */ 8962 if (size > sizeof(*attr)) { 8963 unsigned char __user *addr; 8964 unsigned char __user *end; 8965 unsigned char val; 8966 8967 addr = (void __user *)uattr + sizeof(*attr); 8968 end = (void __user *)uattr + size; 8969 8970 for (; addr < end; addr++) { 8971 ret = get_user(val, addr); 8972 if (ret) 8973 return ret; 8974 if (val) 8975 goto err_size; 8976 } 8977 size = sizeof(*attr); 8978 } 8979 8980 ret = copy_from_user(attr, uattr, size); 8981 if (ret) 8982 return -EFAULT; 8983 8984 if (attr->__reserved_1) 8985 return -EINVAL; 8986 8987 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1)) 8988 return -EINVAL; 8989 8990 if (attr->read_format & ~(PERF_FORMAT_MAX-1)) 8991 return -EINVAL; 8992 8993 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) { 8994 u64 mask = attr->branch_sample_type; 8995 8996 /* only using defined bits */ 8997 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1)) 8998 return -EINVAL; 8999 9000 /* at least one branch bit must be set */ 9001 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL)) 9002 return -EINVAL; 9003 9004 /* propagate priv level, when not set for branch */ 9005 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) { 9006 9007 /* exclude_kernel checked on syscall entry */ 9008 if (!attr->exclude_kernel) 9009 mask |= PERF_SAMPLE_BRANCH_KERNEL; 9010 9011 if (!attr->exclude_user) 9012 mask |= PERF_SAMPLE_BRANCH_USER; 9013 9014 if (!attr->exclude_hv) 9015 mask |= PERF_SAMPLE_BRANCH_HV; 9016 /* 9017 * adjust user setting (for HW filter setup) 9018 */ 9019 attr->branch_sample_type = mask; 9020 } 9021 /* privileged levels capture (kernel, hv): check permissions */ 9022 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM) 9023 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) 9024 return -EACCES; 9025 } 9026 9027 if (attr->sample_type & PERF_SAMPLE_REGS_USER) { 9028 ret = perf_reg_validate(attr->sample_regs_user); 9029 if (ret) 9030 return ret; 9031 } 9032 9033 if (attr->sample_type & PERF_SAMPLE_STACK_USER) { 9034 if (!arch_perf_have_user_stack_dump()) 9035 return -ENOSYS; 9036 9037 /* 9038 * We have __u32 type for the size, but so far 9039 * we can only use __u16 as maximum due to the 9040 * __u16 sample size limit. 9041 */ 9042 if (attr->sample_stack_user >= USHRT_MAX) 9043 ret = -EINVAL; 9044 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64))) 9045 ret = -EINVAL; 9046 } 9047 9048 if (attr->sample_type & PERF_SAMPLE_REGS_INTR) 9049 ret = perf_reg_validate(attr->sample_regs_intr); 9050 out: 9051 return ret; 9052 9053 err_size: 9054 put_user(sizeof(*attr), &uattr->size); 9055 ret = -E2BIG; 9056 goto out; 9057 } 9058 9059 static int 9060 perf_event_set_output(struct perf_event *event, struct perf_event *output_event) 9061 { 9062 struct ring_buffer *rb = NULL; 9063 int ret = -EINVAL; 9064 9065 if (!output_event) 9066 goto set; 9067 9068 /* don't allow circular references */ 9069 if (event == output_event) 9070 goto out; 9071 9072 /* 9073 * Don't allow cross-cpu buffers 9074 */ 9075 if (output_event->cpu != event->cpu) 9076 goto out; 9077 9078 /* 9079 * If its not a per-cpu rb, it must be the same task. 9080 */ 9081 if (output_event->cpu == -1 && output_event->ctx != event->ctx) 9082 goto out; 9083 9084 /* 9085 * Mixing clocks in the same buffer is trouble you don't need. 9086 */ 9087 if (output_event->clock != event->clock) 9088 goto out; 9089 9090 /* 9091 * Either writing ring buffer from beginning or from end. 9092 * Mixing is not allowed. 9093 */ 9094 if (is_write_backward(output_event) != is_write_backward(event)) 9095 goto out; 9096 9097 /* 9098 * If both events generate aux data, they must be on the same PMU 9099 */ 9100 if (has_aux(event) && has_aux(output_event) && 9101 event->pmu != output_event->pmu) 9102 goto out; 9103 9104 set: 9105 mutex_lock(&event->mmap_mutex); 9106 /* Can't redirect output if we've got an active mmap() */ 9107 if (atomic_read(&event->mmap_count)) 9108 goto unlock; 9109 9110 if (output_event) { 9111 /* get the rb we want to redirect to */ 9112 rb = ring_buffer_get(output_event); 9113 if (!rb) 9114 goto unlock; 9115 } 9116 9117 ring_buffer_attach(event, rb); 9118 9119 ret = 0; 9120 unlock: 9121 mutex_unlock(&event->mmap_mutex); 9122 9123 out: 9124 return ret; 9125 } 9126 9127 static void mutex_lock_double(struct mutex *a, struct mutex *b) 9128 { 9129 if (b < a) 9130 swap(a, b); 9131 9132 mutex_lock(a); 9133 mutex_lock_nested(b, SINGLE_DEPTH_NESTING); 9134 } 9135 9136 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id) 9137 { 9138 bool nmi_safe = false; 9139 9140 switch (clk_id) { 9141 case CLOCK_MONOTONIC: 9142 event->clock = &ktime_get_mono_fast_ns; 9143 nmi_safe = true; 9144 break; 9145 9146 case CLOCK_MONOTONIC_RAW: 9147 event->clock = &ktime_get_raw_fast_ns; 9148 nmi_safe = true; 9149 break; 9150 9151 case CLOCK_REALTIME: 9152 event->clock = &ktime_get_real_ns; 9153 break; 9154 9155 case CLOCK_BOOTTIME: 9156 event->clock = &ktime_get_boot_ns; 9157 break; 9158 9159 case CLOCK_TAI: 9160 event->clock = &ktime_get_tai_ns; 9161 break; 9162 9163 default: 9164 return -EINVAL; 9165 } 9166 9167 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI)) 9168 return -EINVAL; 9169 9170 return 0; 9171 } 9172 9173 /** 9174 * sys_perf_event_open - open a performance event, associate it to a task/cpu 9175 * 9176 * @attr_uptr: event_id type attributes for monitoring/sampling 9177 * @pid: target pid 9178 * @cpu: target cpu 9179 * @group_fd: group leader event fd 9180 */ 9181 SYSCALL_DEFINE5(perf_event_open, 9182 struct perf_event_attr __user *, attr_uptr, 9183 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags) 9184 { 9185 struct perf_event *group_leader = NULL, *output_event = NULL; 9186 struct perf_event *event, *sibling; 9187 struct perf_event_attr attr; 9188 struct perf_event_context *ctx, *uninitialized_var(gctx); 9189 struct file *event_file = NULL; 9190 struct fd group = {NULL, 0}; 9191 struct task_struct *task = NULL; 9192 struct pmu *pmu; 9193 int event_fd; 9194 int move_group = 0; 9195 int err; 9196 int f_flags = O_RDWR; 9197 int cgroup_fd = -1; 9198 9199 /* for future expandability... */ 9200 if (flags & ~PERF_FLAG_ALL) 9201 return -EINVAL; 9202 9203 err = perf_copy_attr(attr_uptr, &attr); 9204 if (err) 9205 return err; 9206 9207 if (!attr.exclude_kernel) { 9208 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) 9209 return -EACCES; 9210 } 9211 9212 if (attr.freq) { 9213 if (attr.sample_freq > sysctl_perf_event_sample_rate) 9214 return -EINVAL; 9215 } else { 9216 if (attr.sample_period & (1ULL << 63)) 9217 return -EINVAL; 9218 } 9219 9220 /* 9221 * In cgroup mode, the pid argument is used to pass the fd 9222 * opened to the cgroup directory in cgroupfs. The cpu argument 9223 * designates the cpu on which to monitor threads from that 9224 * cgroup. 9225 */ 9226 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1)) 9227 return -EINVAL; 9228 9229 if (flags & PERF_FLAG_FD_CLOEXEC) 9230 f_flags |= O_CLOEXEC; 9231 9232 event_fd = get_unused_fd_flags(f_flags); 9233 if (event_fd < 0) 9234 return event_fd; 9235 9236 if (group_fd != -1) { 9237 err = perf_fget_light(group_fd, &group); 9238 if (err) 9239 goto err_fd; 9240 group_leader = group.file->private_data; 9241 if (flags & PERF_FLAG_FD_OUTPUT) 9242 output_event = group_leader; 9243 if (flags & PERF_FLAG_FD_NO_GROUP) 9244 group_leader = NULL; 9245 } 9246 9247 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) { 9248 task = find_lively_task_by_vpid(pid); 9249 if (IS_ERR(task)) { 9250 err = PTR_ERR(task); 9251 goto err_group_fd; 9252 } 9253 } 9254 9255 if (task && group_leader && 9256 group_leader->attr.inherit != attr.inherit) { 9257 err = -EINVAL; 9258 goto err_task; 9259 } 9260 9261 get_online_cpus(); 9262 9263 if (task) { 9264 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex); 9265 if (err) 9266 goto err_cpus; 9267 9268 /* 9269 * Reuse ptrace permission checks for now. 9270 * 9271 * We must hold cred_guard_mutex across this and any potential 9272 * perf_install_in_context() call for this new event to 9273 * serialize against exec() altering our credentials (and the 9274 * perf_event_exit_task() that could imply). 9275 */ 9276 err = -EACCES; 9277 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) 9278 goto err_cred; 9279 } 9280 9281 if (flags & PERF_FLAG_PID_CGROUP) 9282 cgroup_fd = pid; 9283 9284 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, 9285 NULL, NULL, cgroup_fd); 9286 if (IS_ERR(event)) { 9287 err = PTR_ERR(event); 9288 goto err_cred; 9289 } 9290 9291 if (is_sampling_event(event)) { 9292 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) { 9293 err = -ENOTSUPP; 9294 goto err_alloc; 9295 } 9296 } 9297 9298 /* 9299 * Special case software events and allow them to be part of 9300 * any hardware group. 9301 */ 9302 pmu = event->pmu; 9303 9304 if (attr.use_clockid) { 9305 err = perf_event_set_clock(event, attr.clockid); 9306 if (err) 9307 goto err_alloc; 9308 } 9309 9310 if (group_leader && 9311 (is_software_event(event) != is_software_event(group_leader))) { 9312 if (is_software_event(event)) { 9313 /* 9314 * If event and group_leader are not both a software 9315 * event, and event is, then group leader is not. 9316 * 9317 * Allow the addition of software events to !software 9318 * groups, this is safe because software events never 9319 * fail to schedule. 9320 */ 9321 pmu = group_leader->pmu; 9322 } else if (is_software_event(group_leader) && 9323 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) { 9324 /* 9325 * In case the group is a pure software group, and we 9326 * try to add a hardware event, move the whole group to 9327 * the hardware context. 9328 */ 9329 move_group = 1; 9330 } 9331 } 9332 9333 /* 9334 * Get the target context (task or percpu): 9335 */ 9336 ctx = find_get_context(pmu, task, event); 9337 if (IS_ERR(ctx)) { 9338 err = PTR_ERR(ctx); 9339 goto err_alloc; 9340 } 9341 9342 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) { 9343 err = -EBUSY; 9344 goto err_context; 9345 } 9346 9347 /* 9348 * Look up the group leader (we will attach this event to it): 9349 */ 9350 if (group_leader) { 9351 err = -EINVAL; 9352 9353 /* 9354 * Do not allow a recursive hierarchy (this new sibling 9355 * becoming part of another group-sibling): 9356 */ 9357 if (group_leader->group_leader != group_leader) 9358 goto err_context; 9359 9360 /* All events in a group should have the same clock */ 9361 if (group_leader->clock != event->clock) 9362 goto err_context; 9363 9364 /* 9365 * Do not allow to attach to a group in a different 9366 * task or CPU context: 9367 */ 9368 if (move_group) { 9369 /* 9370 * Make sure we're both on the same task, or both 9371 * per-cpu events. 9372 */ 9373 if (group_leader->ctx->task != ctx->task) 9374 goto err_context; 9375 9376 /* 9377 * Make sure we're both events for the same CPU; 9378 * grouping events for different CPUs is broken; since 9379 * you can never concurrently schedule them anyhow. 9380 */ 9381 if (group_leader->cpu != event->cpu) 9382 goto err_context; 9383 } else { 9384 if (group_leader->ctx != ctx) 9385 goto err_context; 9386 } 9387 9388 /* 9389 * Only a group leader can be exclusive or pinned 9390 */ 9391 if (attr.exclusive || attr.pinned) 9392 goto err_context; 9393 } 9394 9395 if (output_event) { 9396 err = perf_event_set_output(event, output_event); 9397 if (err) 9398 goto err_context; 9399 } 9400 9401 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, 9402 f_flags); 9403 if (IS_ERR(event_file)) { 9404 err = PTR_ERR(event_file); 9405 event_file = NULL; 9406 goto err_context; 9407 } 9408 9409 if (move_group) { 9410 gctx = group_leader->ctx; 9411 mutex_lock_double(&gctx->mutex, &ctx->mutex); 9412 if (gctx->task == TASK_TOMBSTONE) { 9413 err = -ESRCH; 9414 goto err_locked; 9415 } 9416 } else { 9417 mutex_lock(&ctx->mutex); 9418 } 9419 9420 if (ctx->task == TASK_TOMBSTONE) { 9421 err = -ESRCH; 9422 goto err_locked; 9423 } 9424 9425 if (!perf_event_validate_size(event)) { 9426 err = -E2BIG; 9427 goto err_locked; 9428 } 9429 9430 /* 9431 * Must be under the same ctx::mutex as perf_install_in_context(), 9432 * because we need to serialize with concurrent event creation. 9433 */ 9434 if (!exclusive_event_installable(event, ctx)) { 9435 /* exclusive and group stuff are assumed mutually exclusive */ 9436 WARN_ON_ONCE(move_group); 9437 9438 err = -EBUSY; 9439 goto err_locked; 9440 } 9441 9442 WARN_ON_ONCE(ctx->parent_ctx); 9443 9444 /* 9445 * This is the point on no return; we cannot fail hereafter. This is 9446 * where we start modifying current state. 9447 */ 9448 9449 if (move_group) { 9450 /* 9451 * See perf_event_ctx_lock() for comments on the details 9452 * of swizzling perf_event::ctx. 9453 */ 9454 perf_remove_from_context(group_leader, 0); 9455 9456 list_for_each_entry(sibling, &group_leader->sibling_list, 9457 group_entry) { 9458 perf_remove_from_context(sibling, 0); 9459 put_ctx(gctx); 9460 } 9461 9462 /* 9463 * Wait for everybody to stop referencing the events through 9464 * the old lists, before installing it on new lists. 9465 */ 9466 synchronize_rcu(); 9467 9468 /* 9469 * Install the group siblings before the group leader. 9470 * 9471 * Because a group leader will try and install the entire group 9472 * (through the sibling list, which is still in-tact), we can 9473 * end up with siblings installed in the wrong context. 9474 * 9475 * By installing siblings first we NO-OP because they're not 9476 * reachable through the group lists. 9477 */ 9478 list_for_each_entry(sibling, &group_leader->sibling_list, 9479 group_entry) { 9480 perf_event__state_init(sibling); 9481 perf_install_in_context(ctx, sibling, sibling->cpu); 9482 get_ctx(ctx); 9483 } 9484 9485 /* 9486 * Removing from the context ends up with disabled 9487 * event. What we want here is event in the initial 9488 * startup state, ready to be add into new context. 9489 */ 9490 perf_event__state_init(group_leader); 9491 perf_install_in_context(ctx, group_leader, group_leader->cpu); 9492 get_ctx(ctx); 9493 9494 /* 9495 * Now that all events are installed in @ctx, nothing 9496 * references @gctx anymore, so drop the last reference we have 9497 * on it. 9498 */ 9499 put_ctx(gctx); 9500 } 9501 9502 /* 9503 * Precalculate sample_data sizes; do while holding ctx::mutex such 9504 * that we're serialized against further additions and before 9505 * perf_install_in_context() which is the point the event is active and 9506 * can use these values. 9507 */ 9508 perf_event__header_size(event); 9509 perf_event__id_header_size(event); 9510 9511 event->owner = current; 9512 9513 perf_install_in_context(ctx, event, event->cpu); 9514 perf_unpin_context(ctx); 9515 9516 if (move_group) 9517 mutex_unlock(&gctx->mutex); 9518 mutex_unlock(&ctx->mutex); 9519 9520 if (task) { 9521 mutex_unlock(&task->signal->cred_guard_mutex); 9522 put_task_struct(task); 9523 } 9524 9525 put_online_cpus(); 9526 9527 mutex_lock(¤t->perf_event_mutex); 9528 list_add_tail(&event->owner_entry, ¤t->perf_event_list); 9529 mutex_unlock(¤t->perf_event_mutex); 9530 9531 /* 9532 * Drop the reference on the group_event after placing the 9533 * new event on the sibling_list. This ensures destruction 9534 * of the group leader will find the pointer to itself in 9535 * perf_group_detach(). 9536 */ 9537 fdput(group); 9538 fd_install(event_fd, event_file); 9539 return event_fd; 9540 9541 err_locked: 9542 if (move_group) 9543 mutex_unlock(&gctx->mutex); 9544 mutex_unlock(&ctx->mutex); 9545 /* err_file: */ 9546 fput(event_file); 9547 err_context: 9548 perf_unpin_context(ctx); 9549 put_ctx(ctx); 9550 err_alloc: 9551 /* 9552 * If event_file is set, the fput() above will have called ->release() 9553 * and that will take care of freeing the event. 9554 */ 9555 if (!event_file) 9556 free_event(event); 9557 err_cred: 9558 if (task) 9559 mutex_unlock(&task->signal->cred_guard_mutex); 9560 err_cpus: 9561 put_online_cpus(); 9562 err_task: 9563 if (task) 9564 put_task_struct(task); 9565 err_group_fd: 9566 fdput(group); 9567 err_fd: 9568 put_unused_fd(event_fd); 9569 return err; 9570 } 9571 9572 /** 9573 * perf_event_create_kernel_counter 9574 * 9575 * @attr: attributes of the counter to create 9576 * @cpu: cpu in which the counter is bound 9577 * @task: task to profile (NULL for percpu) 9578 */ 9579 struct perf_event * 9580 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, 9581 struct task_struct *task, 9582 perf_overflow_handler_t overflow_handler, 9583 void *context) 9584 { 9585 struct perf_event_context *ctx; 9586 struct perf_event *event; 9587 int err; 9588 9589 /* 9590 * Get the target context (task or percpu): 9591 */ 9592 9593 event = perf_event_alloc(attr, cpu, task, NULL, NULL, 9594 overflow_handler, context, -1); 9595 if (IS_ERR(event)) { 9596 err = PTR_ERR(event); 9597 goto err; 9598 } 9599 9600 /* Mark owner so we could distinguish it from user events. */ 9601 event->owner = TASK_TOMBSTONE; 9602 9603 ctx = find_get_context(event->pmu, task, event); 9604 if (IS_ERR(ctx)) { 9605 err = PTR_ERR(ctx); 9606 goto err_free; 9607 } 9608 9609 WARN_ON_ONCE(ctx->parent_ctx); 9610 mutex_lock(&ctx->mutex); 9611 if (ctx->task == TASK_TOMBSTONE) { 9612 err = -ESRCH; 9613 goto err_unlock; 9614 } 9615 9616 if (!exclusive_event_installable(event, ctx)) { 9617 err = -EBUSY; 9618 goto err_unlock; 9619 } 9620 9621 perf_install_in_context(ctx, event, cpu); 9622 perf_unpin_context(ctx); 9623 mutex_unlock(&ctx->mutex); 9624 9625 return event; 9626 9627 err_unlock: 9628 mutex_unlock(&ctx->mutex); 9629 perf_unpin_context(ctx); 9630 put_ctx(ctx); 9631 err_free: 9632 free_event(event); 9633 err: 9634 return ERR_PTR(err); 9635 } 9636 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter); 9637 9638 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu) 9639 { 9640 struct perf_event_context *src_ctx; 9641 struct perf_event_context *dst_ctx; 9642 struct perf_event *event, *tmp; 9643 LIST_HEAD(events); 9644 9645 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx; 9646 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx; 9647 9648 /* 9649 * See perf_event_ctx_lock() for comments on the details 9650 * of swizzling perf_event::ctx. 9651 */ 9652 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex); 9653 list_for_each_entry_safe(event, tmp, &src_ctx->event_list, 9654 event_entry) { 9655 perf_remove_from_context(event, 0); 9656 unaccount_event_cpu(event, src_cpu); 9657 put_ctx(src_ctx); 9658 list_add(&event->migrate_entry, &events); 9659 } 9660 9661 /* 9662 * Wait for the events to quiesce before re-instating them. 9663 */ 9664 synchronize_rcu(); 9665 9666 /* 9667 * Re-instate events in 2 passes. 9668 * 9669 * Skip over group leaders and only install siblings on this first 9670 * pass, siblings will not get enabled without a leader, however a 9671 * leader will enable its siblings, even if those are still on the old 9672 * context. 9673 */ 9674 list_for_each_entry_safe(event, tmp, &events, migrate_entry) { 9675 if (event->group_leader == event) 9676 continue; 9677 9678 list_del(&event->migrate_entry); 9679 if (event->state >= PERF_EVENT_STATE_OFF) 9680 event->state = PERF_EVENT_STATE_INACTIVE; 9681 account_event_cpu(event, dst_cpu); 9682 perf_install_in_context(dst_ctx, event, dst_cpu); 9683 get_ctx(dst_ctx); 9684 } 9685 9686 /* 9687 * Once all the siblings are setup properly, install the group leaders 9688 * to make it go. 9689 */ 9690 list_for_each_entry_safe(event, tmp, &events, migrate_entry) { 9691 list_del(&event->migrate_entry); 9692 if (event->state >= PERF_EVENT_STATE_OFF) 9693 event->state = PERF_EVENT_STATE_INACTIVE; 9694 account_event_cpu(event, dst_cpu); 9695 perf_install_in_context(dst_ctx, event, dst_cpu); 9696 get_ctx(dst_ctx); 9697 } 9698 mutex_unlock(&dst_ctx->mutex); 9699 mutex_unlock(&src_ctx->mutex); 9700 } 9701 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context); 9702 9703 static void sync_child_event(struct perf_event *child_event, 9704 struct task_struct *child) 9705 { 9706 struct perf_event *parent_event = child_event->parent; 9707 u64 child_val; 9708 9709 if (child_event->attr.inherit_stat) 9710 perf_event_read_event(child_event, child); 9711 9712 child_val = perf_event_count(child_event); 9713 9714 /* 9715 * Add back the child's count to the parent's count: 9716 */ 9717 atomic64_add(child_val, &parent_event->child_count); 9718 atomic64_add(child_event->total_time_enabled, 9719 &parent_event->child_total_time_enabled); 9720 atomic64_add(child_event->total_time_running, 9721 &parent_event->child_total_time_running); 9722 } 9723 9724 static void 9725 perf_event_exit_event(struct perf_event *child_event, 9726 struct perf_event_context *child_ctx, 9727 struct task_struct *child) 9728 { 9729 struct perf_event *parent_event = child_event->parent; 9730 9731 /* 9732 * Do not destroy the 'original' grouping; because of the context 9733 * switch optimization the original events could've ended up in a 9734 * random child task. 9735 * 9736 * If we were to destroy the original group, all group related 9737 * operations would cease to function properly after this random 9738 * child dies. 9739 * 9740 * Do destroy all inherited groups, we don't care about those 9741 * and being thorough is better. 9742 */ 9743 raw_spin_lock_irq(&child_ctx->lock); 9744 WARN_ON_ONCE(child_ctx->is_active); 9745 9746 if (parent_event) 9747 perf_group_detach(child_event); 9748 list_del_event(child_event, child_ctx); 9749 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */ 9750 raw_spin_unlock_irq(&child_ctx->lock); 9751 9752 /* 9753 * Parent events are governed by their filedesc, retain them. 9754 */ 9755 if (!parent_event) { 9756 perf_event_wakeup(child_event); 9757 return; 9758 } 9759 /* 9760 * Child events can be cleaned up. 9761 */ 9762 9763 sync_child_event(child_event, child); 9764 9765 /* 9766 * Remove this event from the parent's list 9767 */ 9768 WARN_ON_ONCE(parent_event->ctx->parent_ctx); 9769 mutex_lock(&parent_event->child_mutex); 9770 list_del_init(&child_event->child_list); 9771 mutex_unlock(&parent_event->child_mutex); 9772 9773 /* 9774 * Kick perf_poll() for is_event_hup(). 9775 */ 9776 perf_event_wakeup(parent_event); 9777 free_event(child_event); 9778 put_event(parent_event); 9779 } 9780 9781 static void perf_event_exit_task_context(struct task_struct *child, int ctxn) 9782 { 9783 struct perf_event_context *child_ctx, *clone_ctx = NULL; 9784 struct perf_event *child_event, *next; 9785 9786 WARN_ON_ONCE(child != current); 9787 9788 child_ctx = perf_pin_task_context(child, ctxn); 9789 if (!child_ctx) 9790 return; 9791 9792 /* 9793 * In order to reduce the amount of tricky in ctx tear-down, we hold 9794 * ctx::mutex over the entire thing. This serializes against almost 9795 * everything that wants to access the ctx. 9796 * 9797 * The exception is sys_perf_event_open() / 9798 * perf_event_create_kernel_count() which does find_get_context() 9799 * without ctx::mutex (it cannot because of the move_group double mutex 9800 * lock thing). See the comments in perf_install_in_context(). 9801 */ 9802 mutex_lock(&child_ctx->mutex); 9803 9804 /* 9805 * In a single ctx::lock section, de-schedule the events and detach the 9806 * context from the task such that we cannot ever get it scheduled back 9807 * in. 9808 */ 9809 raw_spin_lock_irq(&child_ctx->lock); 9810 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx); 9811 9812 /* 9813 * Now that the context is inactive, destroy the task <-> ctx relation 9814 * and mark the context dead. 9815 */ 9816 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL); 9817 put_ctx(child_ctx); /* cannot be last */ 9818 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE); 9819 put_task_struct(current); /* cannot be last */ 9820 9821 clone_ctx = unclone_ctx(child_ctx); 9822 raw_spin_unlock_irq(&child_ctx->lock); 9823 9824 if (clone_ctx) 9825 put_ctx(clone_ctx); 9826 9827 /* 9828 * Report the task dead after unscheduling the events so that we 9829 * won't get any samples after PERF_RECORD_EXIT. We can however still 9830 * get a few PERF_RECORD_READ events. 9831 */ 9832 perf_event_task(child, child_ctx, 0); 9833 9834 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry) 9835 perf_event_exit_event(child_event, child_ctx, child); 9836 9837 mutex_unlock(&child_ctx->mutex); 9838 9839 put_ctx(child_ctx); 9840 } 9841 9842 /* 9843 * When a child task exits, feed back event values to parent events. 9844 * 9845 * Can be called with cred_guard_mutex held when called from 9846 * install_exec_creds(). 9847 */ 9848 void perf_event_exit_task(struct task_struct *child) 9849 { 9850 struct perf_event *event, *tmp; 9851 int ctxn; 9852 9853 mutex_lock(&child->perf_event_mutex); 9854 list_for_each_entry_safe(event, tmp, &child->perf_event_list, 9855 owner_entry) { 9856 list_del_init(&event->owner_entry); 9857 9858 /* 9859 * Ensure the list deletion is visible before we clear 9860 * the owner, closes a race against perf_release() where 9861 * we need to serialize on the owner->perf_event_mutex. 9862 */ 9863 smp_store_release(&event->owner, NULL); 9864 } 9865 mutex_unlock(&child->perf_event_mutex); 9866 9867 for_each_task_context_nr(ctxn) 9868 perf_event_exit_task_context(child, ctxn); 9869 9870 /* 9871 * The perf_event_exit_task_context calls perf_event_task 9872 * with child's task_ctx, which generates EXIT events for 9873 * child contexts and sets child->perf_event_ctxp[] to NULL. 9874 * At this point we need to send EXIT events to cpu contexts. 9875 */ 9876 perf_event_task(child, NULL, 0); 9877 } 9878 9879 static void perf_free_event(struct perf_event *event, 9880 struct perf_event_context *ctx) 9881 { 9882 struct perf_event *parent = event->parent; 9883 9884 if (WARN_ON_ONCE(!parent)) 9885 return; 9886 9887 mutex_lock(&parent->child_mutex); 9888 list_del_init(&event->child_list); 9889 mutex_unlock(&parent->child_mutex); 9890 9891 put_event(parent); 9892 9893 raw_spin_lock_irq(&ctx->lock); 9894 perf_group_detach(event); 9895 list_del_event(event, ctx); 9896 raw_spin_unlock_irq(&ctx->lock); 9897 free_event(event); 9898 } 9899 9900 /* 9901 * Free an unexposed, unused context as created by inheritance by 9902 * perf_event_init_task below, used by fork() in case of fail. 9903 * 9904 * Not all locks are strictly required, but take them anyway to be nice and 9905 * help out with the lockdep assertions. 9906 */ 9907 void perf_event_free_task(struct task_struct *task) 9908 { 9909 struct perf_event_context *ctx; 9910 struct perf_event *event, *tmp; 9911 int ctxn; 9912 9913 for_each_task_context_nr(ctxn) { 9914 ctx = task->perf_event_ctxp[ctxn]; 9915 if (!ctx) 9916 continue; 9917 9918 mutex_lock(&ctx->mutex); 9919 again: 9920 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, 9921 group_entry) 9922 perf_free_event(event, ctx); 9923 9924 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, 9925 group_entry) 9926 perf_free_event(event, ctx); 9927 9928 if (!list_empty(&ctx->pinned_groups) || 9929 !list_empty(&ctx->flexible_groups)) 9930 goto again; 9931 9932 mutex_unlock(&ctx->mutex); 9933 9934 put_ctx(ctx); 9935 } 9936 } 9937 9938 void perf_event_delayed_put(struct task_struct *task) 9939 { 9940 int ctxn; 9941 9942 for_each_task_context_nr(ctxn) 9943 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]); 9944 } 9945 9946 struct file *perf_event_get(unsigned int fd) 9947 { 9948 struct file *file; 9949 9950 file = fget_raw(fd); 9951 if (!file) 9952 return ERR_PTR(-EBADF); 9953 9954 if (file->f_op != &perf_fops) { 9955 fput(file); 9956 return ERR_PTR(-EBADF); 9957 } 9958 9959 return file; 9960 } 9961 9962 const struct perf_event_attr *perf_event_attrs(struct perf_event *event) 9963 { 9964 if (!event) 9965 return ERR_PTR(-EINVAL); 9966 9967 return &event->attr; 9968 } 9969 9970 /* 9971 * inherit a event from parent task to child task: 9972 */ 9973 static struct perf_event * 9974 inherit_event(struct perf_event *parent_event, 9975 struct task_struct *parent, 9976 struct perf_event_context *parent_ctx, 9977 struct task_struct *child, 9978 struct perf_event *group_leader, 9979 struct perf_event_context *child_ctx) 9980 { 9981 enum perf_event_active_state parent_state = parent_event->state; 9982 struct perf_event *child_event; 9983 unsigned long flags; 9984 9985 /* 9986 * Instead of creating recursive hierarchies of events, 9987 * we link inherited events back to the original parent, 9988 * which has a filp for sure, which we use as the reference 9989 * count: 9990 */ 9991 if (parent_event->parent) 9992 parent_event = parent_event->parent; 9993 9994 child_event = perf_event_alloc(&parent_event->attr, 9995 parent_event->cpu, 9996 child, 9997 group_leader, parent_event, 9998 NULL, NULL, -1); 9999 if (IS_ERR(child_event)) 10000 return child_event; 10001 10002 /* 10003 * is_orphaned_event() and list_add_tail(&parent_event->child_list) 10004 * must be under the same lock in order to serialize against 10005 * perf_event_release_kernel(), such that either we must observe 10006 * is_orphaned_event() or they will observe us on the child_list. 10007 */ 10008 mutex_lock(&parent_event->child_mutex); 10009 if (is_orphaned_event(parent_event) || 10010 !atomic_long_inc_not_zero(&parent_event->refcount)) { 10011 mutex_unlock(&parent_event->child_mutex); 10012 free_event(child_event); 10013 return NULL; 10014 } 10015 10016 get_ctx(child_ctx); 10017 10018 /* 10019 * Make the child state follow the state of the parent event, 10020 * not its attr.disabled bit. We hold the parent's mutex, 10021 * so we won't race with perf_event_{en, dis}able_family. 10022 */ 10023 if (parent_state >= PERF_EVENT_STATE_INACTIVE) 10024 child_event->state = PERF_EVENT_STATE_INACTIVE; 10025 else 10026 child_event->state = PERF_EVENT_STATE_OFF; 10027 10028 if (parent_event->attr.freq) { 10029 u64 sample_period = parent_event->hw.sample_period; 10030 struct hw_perf_event *hwc = &child_event->hw; 10031 10032 hwc->sample_period = sample_period; 10033 hwc->last_period = sample_period; 10034 10035 local64_set(&hwc->period_left, sample_period); 10036 } 10037 10038 child_event->ctx = child_ctx; 10039 child_event->overflow_handler = parent_event->overflow_handler; 10040 child_event->overflow_handler_context 10041 = parent_event->overflow_handler_context; 10042 10043 /* 10044 * Precalculate sample_data sizes 10045 */ 10046 perf_event__header_size(child_event); 10047 perf_event__id_header_size(child_event); 10048 10049 /* 10050 * Link it up in the child's context: 10051 */ 10052 raw_spin_lock_irqsave(&child_ctx->lock, flags); 10053 add_event_to_ctx(child_event, child_ctx); 10054 raw_spin_unlock_irqrestore(&child_ctx->lock, flags); 10055 10056 /* 10057 * Link this into the parent event's child list 10058 */ 10059 list_add_tail(&child_event->child_list, &parent_event->child_list); 10060 mutex_unlock(&parent_event->child_mutex); 10061 10062 return child_event; 10063 } 10064 10065 static int inherit_group(struct perf_event *parent_event, 10066 struct task_struct *parent, 10067 struct perf_event_context *parent_ctx, 10068 struct task_struct *child, 10069 struct perf_event_context *child_ctx) 10070 { 10071 struct perf_event *leader; 10072 struct perf_event *sub; 10073 struct perf_event *child_ctr; 10074 10075 leader = inherit_event(parent_event, parent, parent_ctx, 10076 child, NULL, child_ctx); 10077 if (IS_ERR(leader)) 10078 return PTR_ERR(leader); 10079 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) { 10080 child_ctr = inherit_event(sub, parent, parent_ctx, 10081 child, leader, child_ctx); 10082 if (IS_ERR(child_ctr)) 10083 return PTR_ERR(child_ctr); 10084 } 10085 return 0; 10086 } 10087 10088 static int 10089 inherit_task_group(struct perf_event *event, struct task_struct *parent, 10090 struct perf_event_context *parent_ctx, 10091 struct task_struct *child, int ctxn, 10092 int *inherited_all) 10093 { 10094 int ret; 10095 struct perf_event_context *child_ctx; 10096 10097 if (!event->attr.inherit) { 10098 *inherited_all = 0; 10099 return 0; 10100 } 10101 10102 child_ctx = child->perf_event_ctxp[ctxn]; 10103 if (!child_ctx) { 10104 /* 10105 * This is executed from the parent task context, so 10106 * inherit events that have been marked for cloning. 10107 * First allocate and initialize a context for the 10108 * child. 10109 */ 10110 10111 child_ctx = alloc_perf_context(parent_ctx->pmu, child); 10112 if (!child_ctx) 10113 return -ENOMEM; 10114 10115 child->perf_event_ctxp[ctxn] = child_ctx; 10116 } 10117 10118 ret = inherit_group(event, parent, parent_ctx, 10119 child, child_ctx); 10120 10121 if (ret) 10122 *inherited_all = 0; 10123 10124 return ret; 10125 } 10126 10127 /* 10128 * Initialize the perf_event context in task_struct 10129 */ 10130 static int perf_event_init_context(struct task_struct *child, int ctxn) 10131 { 10132 struct perf_event_context *child_ctx, *parent_ctx; 10133 struct perf_event_context *cloned_ctx; 10134 struct perf_event *event; 10135 struct task_struct *parent = current; 10136 int inherited_all = 1; 10137 unsigned long flags; 10138 int ret = 0; 10139 10140 if (likely(!parent->perf_event_ctxp[ctxn])) 10141 return 0; 10142 10143 /* 10144 * If the parent's context is a clone, pin it so it won't get 10145 * swapped under us. 10146 */ 10147 parent_ctx = perf_pin_task_context(parent, ctxn); 10148 if (!parent_ctx) 10149 return 0; 10150 10151 /* 10152 * No need to check if parent_ctx != NULL here; since we saw 10153 * it non-NULL earlier, the only reason for it to become NULL 10154 * is if we exit, and since we're currently in the middle of 10155 * a fork we can't be exiting at the same time. 10156 */ 10157 10158 /* 10159 * Lock the parent list. No need to lock the child - not PID 10160 * hashed yet and not running, so nobody can access it. 10161 */ 10162 mutex_lock(&parent_ctx->mutex); 10163 10164 /* 10165 * We dont have to disable NMIs - we are only looking at 10166 * the list, not manipulating it: 10167 */ 10168 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) { 10169 ret = inherit_task_group(event, parent, parent_ctx, 10170 child, ctxn, &inherited_all); 10171 if (ret) 10172 break; 10173 } 10174 10175 /* 10176 * We can't hold ctx->lock when iterating the ->flexible_group list due 10177 * to allocations, but we need to prevent rotation because 10178 * rotate_ctx() will change the list from interrupt context. 10179 */ 10180 raw_spin_lock_irqsave(&parent_ctx->lock, flags); 10181 parent_ctx->rotate_disable = 1; 10182 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); 10183 10184 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) { 10185 ret = inherit_task_group(event, parent, parent_ctx, 10186 child, ctxn, &inherited_all); 10187 if (ret) 10188 break; 10189 } 10190 10191 raw_spin_lock_irqsave(&parent_ctx->lock, flags); 10192 parent_ctx->rotate_disable = 0; 10193 10194 child_ctx = child->perf_event_ctxp[ctxn]; 10195 10196 if (child_ctx && inherited_all) { 10197 /* 10198 * Mark the child context as a clone of the parent 10199 * context, or of whatever the parent is a clone of. 10200 * 10201 * Note that if the parent is a clone, the holding of 10202 * parent_ctx->lock avoids it from being uncloned. 10203 */ 10204 cloned_ctx = parent_ctx->parent_ctx; 10205 if (cloned_ctx) { 10206 child_ctx->parent_ctx = cloned_ctx; 10207 child_ctx->parent_gen = parent_ctx->parent_gen; 10208 } else { 10209 child_ctx->parent_ctx = parent_ctx; 10210 child_ctx->parent_gen = parent_ctx->generation; 10211 } 10212 get_ctx(child_ctx->parent_ctx); 10213 } 10214 10215 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); 10216 mutex_unlock(&parent_ctx->mutex); 10217 10218 perf_unpin_context(parent_ctx); 10219 put_ctx(parent_ctx); 10220 10221 return ret; 10222 } 10223 10224 /* 10225 * Initialize the perf_event context in task_struct 10226 */ 10227 int perf_event_init_task(struct task_struct *child) 10228 { 10229 int ctxn, ret; 10230 10231 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp)); 10232 mutex_init(&child->perf_event_mutex); 10233 INIT_LIST_HEAD(&child->perf_event_list); 10234 10235 for_each_task_context_nr(ctxn) { 10236 ret = perf_event_init_context(child, ctxn); 10237 if (ret) { 10238 perf_event_free_task(child); 10239 return ret; 10240 } 10241 } 10242 10243 return 0; 10244 } 10245 10246 static void __init perf_event_init_all_cpus(void) 10247 { 10248 struct swevent_htable *swhash; 10249 int cpu; 10250 10251 for_each_possible_cpu(cpu) { 10252 swhash = &per_cpu(swevent_htable, cpu); 10253 mutex_init(&swhash->hlist_mutex); 10254 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu)); 10255 } 10256 } 10257 10258 static void perf_event_init_cpu(int cpu) 10259 { 10260 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 10261 10262 mutex_lock(&swhash->hlist_mutex); 10263 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) { 10264 struct swevent_hlist *hlist; 10265 10266 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu)); 10267 WARN_ON(!hlist); 10268 rcu_assign_pointer(swhash->swevent_hlist, hlist); 10269 } 10270 mutex_unlock(&swhash->hlist_mutex); 10271 } 10272 10273 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE 10274 static void __perf_event_exit_context(void *__info) 10275 { 10276 struct perf_event_context *ctx = __info; 10277 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 10278 struct perf_event *event; 10279 10280 raw_spin_lock(&ctx->lock); 10281 list_for_each_entry(event, &ctx->event_list, event_entry) 10282 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP); 10283 raw_spin_unlock(&ctx->lock); 10284 } 10285 10286 static void perf_event_exit_cpu_context(int cpu) 10287 { 10288 struct perf_event_context *ctx; 10289 struct pmu *pmu; 10290 int idx; 10291 10292 idx = srcu_read_lock(&pmus_srcu); 10293 list_for_each_entry_rcu(pmu, &pmus, entry) { 10294 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx; 10295 10296 mutex_lock(&ctx->mutex); 10297 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1); 10298 mutex_unlock(&ctx->mutex); 10299 } 10300 srcu_read_unlock(&pmus_srcu, idx); 10301 } 10302 10303 static void perf_event_exit_cpu(int cpu) 10304 { 10305 perf_event_exit_cpu_context(cpu); 10306 } 10307 #else 10308 static inline void perf_event_exit_cpu(int cpu) { } 10309 #endif 10310 10311 static int 10312 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v) 10313 { 10314 int cpu; 10315 10316 for_each_online_cpu(cpu) 10317 perf_event_exit_cpu(cpu); 10318 10319 return NOTIFY_OK; 10320 } 10321 10322 /* 10323 * Run the perf reboot notifier at the very last possible moment so that 10324 * the generic watchdog code runs as long as possible. 10325 */ 10326 static struct notifier_block perf_reboot_notifier = { 10327 .notifier_call = perf_reboot, 10328 .priority = INT_MIN, 10329 }; 10330 10331 static int 10332 perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) 10333 { 10334 unsigned int cpu = (long)hcpu; 10335 10336 switch (action & ~CPU_TASKS_FROZEN) { 10337 10338 case CPU_UP_PREPARE: 10339 /* 10340 * This must be done before the CPU comes alive, because the 10341 * moment we can run tasks we can encounter (software) events. 10342 * 10343 * Specifically, someone can have inherited events on kthreadd 10344 * or a pre-existing worker thread that gets re-bound. 10345 */ 10346 perf_event_init_cpu(cpu); 10347 break; 10348 10349 case CPU_DOWN_PREPARE: 10350 /* 10351 * This must be done before the CPU dies because after that an 10352 * active event might want to IPI the CPU and that'll not work 10353 * so great for dead CPUs. 10354 * 10355 * XXX smp_call_function_single() return -ENXIO without a warn 10356 * so we could possibly deal with this. 10357 * 10358 * This is safe against new events arriving because 10359 * sys_perf_event_open() serializes against hotplug using 10360 * get_online_cpus(). 10361 */ 10362 perf_event_exit_cpu(cpu); 10363 break; 10364 default: 10365 break; 10366 } 10367 10368 return NOTIFY_OK; 10369 } 10370 10371 void __init perf_event_init(void) 10372 { 10373 int ret; 10374 10375 idr_init(&pmu_idr); 10376 10377 perf_event_init_all_cpus(); 10378 init_srcu_struct(&pmus_srcu); 10379 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE); 10380 perf_pmu_register(&perf_cpu_clock, NULL, -1); 10381 perf_pmu_register(&perf_task_clock, NULL, -1); 10382 perf_tp_register(); 10383 perf_cpu_notifier(perf_cpu_notify); 10384 register_reboot_notifier(&perf_reboot_notifier); 10385 10386 ret = init_hw_breakpoint(); 10387 WARN(ret, "hw_breakpoint initialization failed with: %d", ret); 10388 10389 /* 10390 * Build time assertion that we keep the data_head at the intended 10391 * location. IOW, validation we got the __reserved[] size right. 10392 */ 10393 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head)) 10394 != 1024); 10395 } 10396 10397 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr, 10398 char *page) 10399 { 10400 struct perf_pmu_events_attr *pmu_attr = 10401 container_of(attr, struct perf_pmu_events_attr, attr); 10402 10403 if (pmu_attr->event_str) 10404 return sprintf(page, "%s\n", pmu_attr->event_str); 10405 10406 return 0; 10407 } 10408 EXPORT_SYMBOL_GPL(perf_event_sysfs_show); 10409 10410 static int __init perf_event_sysfs_init(void) 10411 { 10412 struct pmu *pmu; 10413 int ret; 10414 10415 mutex_lock(&pmus_lock); 10416 10417 ret = bus_register(&pmu_bus); 10418 if (ret) 10419 goto unlock; 10420 10421 list_for_each_entry(pmu, &pmus, entry) { 10422 if (!pmu->name || pmu->type < 0) 10423 continue; 10424 10425 ret = pmu_dev_alloc(pmu); 10426 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret); 10427 } 10428 pmu_bus_running = 1; 10429 ret = 0; 10430 10431 unlock: 10432 mutex_unlock(&pmus_lock); 10433 10434 return ret; 10435 } 10436 device_initcall(perf_event_sysfs_init); 10437 10438 #ifdef CONFIG_CGROUP_PERF 10439 static struct cgroup_subsys_state * 10440 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) 10441 { 10442 struct perf_cgroup *jc; 10443 10444 jc = kzalloc(sizeof(*jc), GFP_KERNEL); 10445 if (!jc) 10446 return ERR_PTR(-ENOMEM); 10447 10448 jc->info = alloc_percpu(struct perf_cgroup_info); 10449 if (!jc->info) { 10450 kfree(jc); 10451 return ERR_PTR(-ENOMEM); 10452 } 10453 10454 return &jc->css; 10455 } 10456 10457 static void perf_cgroup_css_free(struct cgroup_subsys_state *css) 10458 { 10459 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css); 10460 10461 free_percpu(jc->info); 10462 kfree(jc); 10463 } 10464 10465 static int __perf_cgroup_move(void *info) 10466 { 10467 struct task_struct *task = info; 10468 rcu_read_lock(); 10469 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN); 10470 rcu_read_unlock(); 10471 return 0; 10472 } 10473 10474 static void perf_cgroup_attach(struct cgroup_taskset *tset) 10475 { 10476 struct task_struct *task; 10477 struct cgroup_subsys_state *css; 10478 10479 cgroup_taskset_for_each(task, css, tset) 10480 task_function_call(task, __perf_cgroup_move, task); 10481 } 10482 10483 struct cgroup_subsys perf_event_cgrp_subsys = { 10484 .css_alloc = perf_cgroup_css_alloc, 10485 .css_free = perf_cgroup_css_free, 10486 .attach = perf_cgroup_attach, 10487 }; 10488 #endif /* CONFIG_CGROUP_PERF */ 10489