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 #include <linux/sched/clock.h> 50 #include <linux/sched/mm.h> 51 #include <linux/proc_ns.h> 52 #include <linux/mount.h> 53 54 #include "internal.h" 55 56 #include <asm/irq_regs.h> 57 58 typedef int (*remote_function_f)(void *); 59 60 struct remote_function_call { 61 struct task_struct *p; 62 remote_function_f func; 63 void *info; 64 int ret; 65 }; 66 67 static void remote_function(void *data) 68 { 69 struct remote_function_call *tfc = data; 70 struct task_struct *p = tfc->p; 71 72 if (p) { 73 /* -EAGAIN */ 74 if (task_cpu(p) != smp_processor_id()) 75 return; 76 77 /* 78 * Now that we're on right CPU with IRQs disabled, we can test 79 * if we hit the right task without races. 80 */ 81 82 tfc->ret = -ESRCH; /* No such (running) process */ 83 if (p != current) 84 return; 85 } 86 87 tfc->ret = tfc->func(tfc->info); 88 } 89 90 /** 91 * task_function_call - call a function on the cpu on which a task runs 92 * @p: the task to evaluate 93 * @func: the function to be called 94 * @info: the function call argument 95 * 96 * Calls the function @func when the task is currently running. This might 97 * be on the current CPU, which just calls the function directly 98 * 99 * returns: @func return value, or 100 * -ESRCH - when the process isn't running 101 * -EAGAIN - when the process moved away 102 */ 103 static int 104 task_function_call(struct task_struct *p, remote_function_f func, void *info) 105 { 106 struct remote_function_call data = { 107 .p = p, 108 .func = func, 109 .info = info, 110 .ret = -EAGAIN, 111 }; 112 int ret; 113 114 do { 115 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1); 116 if (!ret) 117 ret = data.ret; 118 } while (ret == -EAGAIN); 119 120 return ret; 121 } 122 123 /** 124 * cpu_function_call - call a function on the cpu 125 * @func: the function to be called 126 * @info: the function call argument 127 * 128 * Calls the function @func on the remote cpu. 129 * 130 * returns: @func return value or -ENXIO when the cpu is offline 131 */ 132 static int cpu_function_call(int cpu, remote_function_f func, void *info) 133 { 134 struct remote_function_call data = { 135 .p = NULL, 136 .func = func, 137 .info = info, 138 .ret = -ENXIO, /* No such CPU */ 139 }; 140 141 smp_call_function_single(cpu, remote_function, &data, 1); 142 143 return data.ret; 144 } 145 146 static inline struct perf_cpu_context * 147 __get_cpu_context(struct perf_event_context *ctx) 148 { 149 return this_cpu_ptr(ctx->pmu->pmu_cpu_context); 150 } 151 152 static void perf_ctx_lock(struct perf_cpu_context *cpuctx, 153 struct perf_event_context *ctx) 154 { 155 raw_spin_lock(&cpuctx->ctx.lock); 156 if (ctx) 157 raw_spin_lock(&ctx->lock); 158 } 159 160 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx, 161 struct perf_event_context *ctx) 162 { 163 if (ctx) 164 raw_spin_unlock(&ctx->lock); 165 raw_spin_unlock(&cpuctx->ctx.lock); 166 } 167 168 #define TASK_TOMBSTONE ((void *)-1L) 169 170 static bool is_kernel_event(struct perf_event *event) 171 { 172 return READ_ONCE(event->owner) == TASK_TOMBSTONE; 173 } 174 175 /* 176 * On task ctx scheduling... 177 * 178 * When !ctx->nr_events a task context will not be scheduled. This means 179 * we can disable the scheduler hooks (for performance) without leaving 180 * pending task ctx state. 181 * 182 * This however results in two special cases: 183 * 184 * - removing the last event from a task ctx; this is relatively straight 185 * forward and is done in __perf_remove_from_context. 186 * 187 * - adding the first event to a task ctx; this is tricky because we cannot 188 * rely on ctx->is_active and therefore cannot use event_function_call(). 189 * See perf_install_in_context(). 190 * 191 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set. 192 */ 193 194 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *, 195 struct perf_event_context *, void *); 196 197 struct event_function_struct { 198 struct perf_event *event; 199 event_f func; 200 void *data; 201 }; 202 203 static int event_function(void *info) 204 { 205 struct event_function_struct *efs = info; 206 struct perf_event *event = efs->event; 207 struct perf_event_context *ctx = event->ctx; 208 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 209 struct perf_event_context *task_ctx = cpuctx->task_ctx; 210 int ret = 0; 211 212 WARN_ON_ONCE(!irqs_disabled()); 213 214 perf_ctx_lock(cpuctx, task_ctx); 215 /* 216 * Since we do the IPI call without holding ctx->lock things can have 217 * changed, double check we hit the task we set out to hit. 218 */ 219 if (ctx->task) { 220 if (ctx->task != current) { 221 ret = -ESRCH; 222 goto unlock; 223 } 224 225 /* 226 * We only use event_function_call() on established contexts, 227 * and event_function() is only ever called when active (or 228 * rather, we'll have bailed in task_function_call() or the 229 * above ctx->task != current test), therefore we must have 230 * ctx->is_active here. 231 */ 232 WARN_ON_ONCE(!ctx->is_active); 233 /* 234 * And since we have ctx->is_active, cpuctx->task_ctx must 235 * match. 236 */ 237 WARN_ON_ONCE(task_ctx != ctx); 238 } else { 239 WARN_ON_ONCE(&cpuctx->ctx != ctx); 240 } 241 242 efs->func(event, cpuctx, ctx, efs->data); 243 unlock: 244 perf_ctx_unlock(cpuctx, task_ctx); 245 246 return ret; 247 } 248 249 static void event_function_call(struct perf_event *event, event_f func, void *data) 250 { 251 struct perf_event_context *ctx = event->ctx; 252 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */ 253 struct event_function_struct efs = { 254 .event = event, 255 .func = func, 256 .data = data, 257 }; 258 259 if (!event->parent) { 260 /* 261 * If this is a !child event, we must hold ctx::mutex to 262 * stabilize the the event->ctx relation. See 263 * perf_event_ctx_lock(). 264 */ 265 lockdep_assert_held(&ctx->mutex); 266 } 267 268 if (!task) { 269 cpu_function_call(event->cpu, event_function, &efs); 270 return; 271 } 272 273 if (task == TASK_TOMBSTONE) 274 return; 275 276 again: 277 if (!task_function_call(task, event_function, &efs)) 278 return; 279 280 raw_spin_lock_irq(&ctx->lock); 281 /* 282 * Reload the task pointer, it might have been changed by 283 * a concurrent perf_event_context_sched_out(). 284 */ 285 task = ctx->task; 286 if (task == TASK_TOMBSTONE) { 287 raw_spin_unlock_irq(&ctx->lock); 288 return; 289 } 290 if (ctx->is_active) { 291 raw_spin_unlock_irq(&ctx->lock); 292 goto again; 293 } 294 func(event, NULL, ctx, data); 295 raw_spin_unlock_irq(&ctx->lock); 296 } 297 298 /* 299 * Similar to event_function_call() + event_function(), but hard assumes IRQs 300 * are already disabled and we're on the right CPU. 301 */ 302 static void event_function_local(struct perf_event *event, event_f func, void *data) 303 { 304 struct perf_event_context *ctx = event->ctx; 305 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 306 struct task_struct *task = READ_ONCE(ctx->task); 307 struct perf_event_context *task_ctx = NULL; 308 309 WARN_ON_ONCE(!irqs_disabled()); 310 311 if (task) { 312 if (task == TASK_TOMBSTONE) 313 return; 314 315 task_ctx = ctx; 316 } 317 318 perf_ctx_lock(cpuctx, task_ctx); 319 320 task = ctx->task; 321 if (task == TASK_TOMBSTONE) 322 goto unlock; 323 324 if (task) { 325 /* 326 * We must be either inactive or active and the right task, 327 * otherwise we're screwed, since we cannot IPI to somewhere 328 * else. 329 */ 330 if (ctx->is_active) { 331 if (WARN_ON_ONCE(task != current)) 332 goto unlock; 333 334 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx)) 335 goto unlock; 336 } 337 } else { 338 WARN_ON_ONCE(&cpuctx->ctx != ctx); 339 } 340 341 func(event, cpuctx, ctx, data); 342 unlock: 343 perf_ctx_unlock(cpuctx, task_ctx); 344 } 345 346 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\ 347 PERF_FLAG_FD_OUTPUT |\ 348 PERF_FLAG_PID_CGROUP |\ 349 PERF_FLAG_FD_CLOEXEC) 350 351 /* 352 * branch priv levels that need permission checks 353 */ 354 #define PERF_SAMPLE_BRANCH_PERM_PLM \ 355 (PERF_SAMPLE_BRANCH_KERNEL |\ 356 PERF_SAMPLE_BRANCH_HV) 357 358 enum event_type_t { 359 EVENT_FLEXIBLE = 0x1, 360 EVENT_PINNED = 0x2, 361 EVENT_TIME = 0x4, 362 /* see ctx_resched() for details */ 363 EVENT_CPU = 0x8, 364 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED, 365 }; 366 367 /* 368 * perf_sched_events : >0 events exist 369 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu 370 */ 371 372 static void perf_sched_delayed(struct work_struct *work); 373 DEFINE_STATIC_KEY_FALSE(perf_sched_events); 374 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed); 375 static DEFINE_MUTEX(perf_sched_mutex); 376 static atomic_t perf_sched_count; 377 378 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events); 379 static DEFINE_PER_CPU(int, perf_sched_cb_usages); 380 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events); 381 382 static atomic_t nr_mmap_events __read_mostly; 383 static atomic_t nr_comm_events __read_mostly; 384 static atomic_t nr_namespaces_events __read_mostly; 385 static atomic_t nr_task_events __read_mostly; 386 static atomic_t nr_freq_events __read_mostly; 387 static atomic_t nr_switch_events __read_mostly; 388 389 static LIST_HEAD(pmus); 390 static DEFINE_MUTEX(pmus_lock); 391 static struct srcu_struct pmus_srcu; 392 393 /* 394 * perf event paranoia level: 395 * -1 - not paranoid at all 396 * 0 - disallow raw tracepoint access for unpriv 397 * 1 - disallow cpu events for unpriv 398 * 2 - disallow kernel profiling for unpriv 399 */ 400 int sysctl_perf_event_paranoid __read_mostly = 2; 401 402 /* Minimum for 512 kiB + 1 user control page */ 403 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */ 404 405 /* 406 * max perf event sample rate 407 */ 408 #define DEFAULT_MAX_SAMPLE_RATE 100000 409 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE) 410 #define DEFAULT_CPU_TIME_MAX_PERCENT 25 411 412 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE; 413 414 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ); 415 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS; 416 417 static int perf_sample_allowed_ns __read_mostly = 418 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100; 419 420 static void update_perf_cpu_limits(void) 421 { 422 u64 tmp = perf_sample_period_ns; 423 424 tmp *= sysctl_perf_cpu_time_max_percent; 425 tmp = div_u64(tmp, 100); 426 if (!tmp) 427 tmp = 1; 428 429 WRITE_ONCE(perf_sample_allowed_ns, tmp); 430 } 431 432 static int perf_rotate_context(struct perf_cpu_context *cpuctx); 433 434 int perf_proc_update_handler(struct ctl_table *table, int write, 435 void __user *buffer, size_t *lenp, 436 loff_t *ppos) 437 { 438 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); 439 440 if (ret || !write) 441 return ret; 442 443 /* 444 * If throttling is disabled don't allow the write: 445 */ 446 if (sysctl_perf_cpu_time_max_percent == 100 || 447 sysctl_perf_cpu_time_max_percent == 0) 448 return -EINVAL; 449 450 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ); 451 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; 452 update_perf_cpu_limits(); 453 454 return 0; 455 } 456 457 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT; 458 459 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write, 460 void __user *buffer, size_t *lenp, 461 loff_t *ppos) 462 { 463 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); 464 465 if (ret || !write) 466 return ret; 467 468 if (sysctl_perf_cpu_time_max_percent == 100 || 469 sysctl_perf_cpu_time_max_percent == 0) { 470 printk(KERN_WARNING 471 "perf: Dynamic interrupt throttling disabled, can hang your system!\n"); 472 WRITE_ONCE(perf_sample_allowed_ns, 0); 473 } else { 474 update_perf_cpu_limits(); 475 } 476 477 return 0; 478 } 479 480 /* 481 * perf samples are done in some very critical code paths (NMIs). 482 * If they take too much CPU time, the system can lock up and not 483 * get any real work done. This will drop the sample rate when 484 * we detect that events are taking too long. 485 */ 486 #define NR_ACCUMULATED_SAMPLES 128 487 static DEFINE_PER_CPU(u64, running_sample_length); 488 489 static u64 __report_avg; 490 static u64 __report_allowed; 491 492 static void perf_duration_warn(struct irq_work *w) 493 { 494 printk_ratelimited(KERN_INFO 495 "perf: interrupt took too long (%lld > %lld), lowering " 496 "kernel.perf_event_max_sample_rate to %d\n", 497 __report_avg, __report_allowed, 498 sysctl_perf_event_sample_rate); 499 } 500 501 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn); 502 503 void perf_sample_event_took(u64 sample_len_ns) 504 { 505 u64 max_len = READ_ONCE(perf_sample_allowed_ns); 506 u64 running_len; 507 u64 avg_len; 508 u32 max; 509 510 if (max_len == 0) 511 return; 512 513 /* Decay the counter by 1 average sample. */ 514 running_len = __this_cpu_read(running_sample_length); 515 running_len -= running_len/NR_ACCUMULATED_SAMPLES; 516 running_len += sample_len_ns; 517 __this_cpu_write(running_sample_length, running_len); 518 519 /* 520 * Note: this will be biased artifically low until we have 521 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us 522 * from having to maintain a count. 523 */ 524 avg_len = running_len/NR_ACCUMULATED_SAMPLES; 525 if (avg_len <= max_len) 526 return; 527 528 __report_avg = avg_len; 529 __report_allowed = max_len; 530 531 /* 532 * Compute a throttle threshold 25% below the current duration. 533 */ 534 avg_len += avg_len / 4; 535 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent; 536 if (avg_len < max) 537 max /= (u32)avg_len; 538 else 539 max = 1; 540 541 WRITE_ONCE(perf_sample_allowed_ns, avg_len); 542 WRITE_ONCE(max_samples_per_tick, max); 543 544 sysctl_perf_event_sample_rate = max * HZ; 545 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; 546 547 if (!irq_work_queue(&perf_duration_work)) { 548 early_printk("perf: interrupt took too long (%lld > %lld), lowering " 549 "kernel.perf_event_max_sample_rate to %d\n", 550 __report_avg, __report_allowed, 551 sysctl_perf_event_sample_rate); 552 } 553 } 554 555 static atomic64_t perf_event_id; 556 557 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, 558 enum event_type_t event_type); 559 560 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, 561 enum event_type_t event_type, 562 struct task_struct *task); 563 564 static void update_context_time(struct perf_event_context *ctx); 565 static u64 perf_event_time(struct perf_event *event); 566 567 void __weak perf_event_print_debug(void) { } 568 569 extern __weak const char *perf_pmu_name(void) 570 { 571 return "pmu"; 572 } 573 574 static inline u64 perf_clock(void) 575 { 576 return local_clock(); 577 } 578 579 static inline u64 perf_event_clock(struct perf_event *event) 580 { 581 return event->clock(); 582 } 583 584 #ifdef CONFIG_CGROUP_PERF 585 586 static inline bool 587 perf_cgroup_match(struct perf_event *event) 588 { 589 struct perf_event_context *ctx = event->ctx; 590 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 591 592 /* @event doesn't care about cgroup */ 593 if (!event->cgrp) 594 return true; 595 596 /* wants specific cgroup scope but @cpuctx isn't associated with any */ 597 if (!cpuctx->cgrp) 598 return false; 599 600 /* 601 * Cgroup scoping is recursive. An event enabled for a cgroup is 602 * also enabled for all its descendant cgroups. If @cpuctx's 603 * cgroup is a descendant of @event's (the test covers identity 604 * case), it's a match. 605 */ 606 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup, 607 event->cgrp->css.cgroup); 608 } 609 610 static inline void perf_detach_cgroup(struct perf_event *event) 611 { 612 css_put(&event->cgrp->css); 613 event->cgrp = NULL; 614 } 615 616 static inline int is_cgroup_event(struct perf_event *event) 617 { 618 return event->cgrp != NULL; 619 } 620 621 static inline u64 perf_cgroup_event_time(struct perf_event *event) 622 { 623 struct perf_cgroup_info *t; 624 625 t = per_cpu_ptr(event->cgrp->info, event->cpu); 626 return t->time; 627 } 628 629 static inline void __update_cgrp_time(struct perf_cgroup *cgrp) 630 { 631 struct perf_cgroup_info *info; 632 u64 now; 633 634 now = perf_clock(); 635 636 info = this_cpu_ptr(cgrp->info); 637 638 info->time += now - info->timestamp; 639 info->timestamp = now; 640 } 641 642 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) 643 { 644 struct perf_cgroup *cgrp_out = cpuctx->cgrp; 645 if (cgrp_out) 646 __update_cgrp_time(cgrp_out); 647 } 648 649 static inline void update_cgrp_time_from_event(struct perf_event *event) 650 { 651 struct perf_cgroup *cgrp; 652 653 /* 654 * ensure we access cgroup data only when needed and 655 * when we know the cgroup is pinned (css_get) 656 */ 657 if (!is_cgroup_event(event)) 658 return; 659 660 cgrp = perf_cgroup_from_task(current, event->ctx); 661 /* 662 * Do not update time when cgroup is not active 663 */ 664 if (cgrp == event->cgrp) 665 __update_cgrp_time(event->cgrp); 666 } 667 668 static inline void 669 perf_cgroup_set_timestamp(struct task_struct *task, 670 struct perf_event_context *ctx) 671 { 672 struct perf_cgroup *cgrp; 673 struct perf_cgroup_info *info; 674 675 /* 676 * ctx->lock held by caller 677 * ensure we do not access cgroup data 678 * unless we have the cgroup pinned (css_get) 679 */ 680 if (!task || !ctx->nr_cgroups) 681 return; 682 683 cgrp = perf_cgroup_from_task(task, ctx); 684 info = this_cpu_ptr(cgrp->info); 685 info->timestamp = ctx->timestamp; 686 } 687 688 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list); 689 690 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */ 691 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */ 692 693 /* 694 * reschedule events based on the cgroup constraint of task. 695 * 696 * mode SWOUT : schedule out everything 697 * mode SWIN : schedule in based on cgroup for next 698 */ 699 static void perf_cgroup_switch(struct task_struct *task, int mode) 700 { 701 struct perf_cpu_context *cpuctx; 702 struct list_head *list; 703 unsigned long flags; 704 705 /* 706 * Disable interrupts and preemption to avoid this CPU's 707 * cgrp_cpuctx_entry to change under us. 708 */ 709 local_irq_save(flags); 710 711 list = this_cpu_ptr(&cgrp_cpuctx_list); 712 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) { 713 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0); 714 715 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 716 perf_pmu_disable(cpuctx->ctx.pmu); 717 718 if (mode & PERF_CGROUP_SWOUT) { 719 cpu_ctx_sched_out(cpuctx, EVENT_ALL); 720 /* 721 * must not be done before ctxswout due 722 * to event_filter_match() in event_sched_out() 723 */ 724 cpuctx->cgrp = NULL; 725 } 726 727 if (mode & PERF_CGROUP_SWIN) { 728 WARN_ON_ONCE(cpuctx->cgrp); 729 /* 730 * set cgrp before ctxsw in to allow 731 * event_filter_match() to not have to pass 732 * task around 733 * we pass the cpuctx->ctx to perf_cgroup_from_task() 734 * because cgorup events are only per-cpu 735 */ 736 cpuctx->cgrp = perf_cgroup_from_task(task, 737 &cpuctx->ctx); 738 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task); 739 } 740 perf_pmu_enable(cpuctx->ctx.pmu); 741 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 742 } 743 744 local_irq_restore(flags); 745 } 746 747 static inline void perf_cgroup_sched_out(struct task_struct *task, 748 struct task_struct *next) 749 { 750 struct perf_cgroup *cgrp1; 751 struct perf_cgroup *cgrp2 = NULL; 752 753 rcu_read_lock(); 754 /* 755 * we come here when we know perf_cgroup_events > 0 756 * we do not need to pass the ctx here because we know 757 * we are holding the rcu lock 758 */ 759 cgrp1 = perf_cgroup_from_task(task, NULL); 760 cgrp2 = perf_cgroup_from_task(next, NULL); 761 762 /* 763 * only schedule out current cgroup events if we know 764 * that we are switching to a different cgroup. Otherwise, 765 * do no touch the cgroup events. 766 */ 767 if (cgrp1 != cgrp2) 768 perf_cgroup_switch(task, PERF_CGROUP_SWOUT); 769 770 rcu_read_unlock(); 771 } 772 773 static inline void perf_cgroup_sched_in(struct task_struct *prev, 774 struct task_struct *task) 775 { 776 struct perf_cgroup *cgrp1; 777 struct perf_cgroup *cgrp2 = NULL; 778 779 rcu_read_lock(); 780 /* 781 * we come here when we know perf_cgroup_events > 0 782 * we do not need to pass the ctx here because we know 783 * we are holding the rcu lock 784 */ 785 cgrp1 = perf_cgroup_from_task(task, NULL); 786 cgrp2 = perf_cgroup_from_task(prev, NULL); 787 788 /* 789 * only need to schedule in cgroup events if we are changing 790 * cgroup during ctxsw. Cgroup events were not scheduled 791 * out of ctxsw out if that was not the case. 792 */ 793 if (cgrp1 != cgrp2) 794 perf_cgroup_switch(task, PERF_CGROUP_SWIN); 795 796 rcu_read_unlock(); 797 } 798 799 static inline int perf_cgroup_connect(int fd, struct perf_event *event, 800 struct perf_event_attr *attr, 801 struct perf_event *group_leader) 802 { 803 struct perf_cgroup *cgrp; 804 struct cgroup_subsys_state *css; 805 struct fd f = fdget(fd); 806 int ret = 0; 807 808 if (!f.file) 809 return -EBADF; 810 811 css = css_tryget_online_from_dir(f.file->f_path.dentry, 812 &perf_event_cgrp_subsys); 813 if (IS_ERR(css)) { 814 ret = PTR_ERR(css); 815 goto out; 816 } 817 818 cgrp = container_of(css, struct perf_cgroup, css); 819 event->cgrp = cgrp; 820 821 /* 822 * all events in a group must monitor 823 * the same cgroup because a task belongs 824 * to only one perf cgroup at a time 825 */ 826 if (group_leader && group_leader->cgrp != cgrp) { 827 perf_detach_cgroup(event); 828 ret = -EINVAL; 829 } 830 out: 831 fdput(f); 832 return ret; 833 } 834 835 static inline void 836 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) 837 { 838 struct perf_cgroup_info *t; 839 t = per_cpu_ptr(event->cgrp->info, event->cpu); 840 event->shadow_ctx_time = now - t->timestamp; 841 } 842 843 static inline void 844 perf_cgroup_defer_enabled(struct perf_event *event) 845 { 846 /* 847 * when the current task's perf cgroup does not match 848 * the event's, we need to remember to call the 849 * perf_mark_enable() function the first time a task with 850 * a matching perf cgroup is scheduled in. 851 */ 852 if (is_cgroup_event(event) && !perf_cgroup_match(event)) 853 event->cgrp_defer_enabled = 1; 854 } 855 856 static inline void 857 perf_cgroup_mark_enabled(struct perf_event *event, 858 struct perf_event_context *ctx) 859 { 860 struct perf_event *sub; 861 u64 tstamp = perf_event_time(event); 862 863 if (!event->cgrp_defer_enabled) 864 return; 865 866 event->cgrp_defer_enabled = 0; 867 868 event->tstamp_enabled = tstamp - event->total_time_enabled; 869 list_for_each_entry(sub, &event->sibling_list, group_entry) { 870 if (sub->state >= PERF_EVENT_STATE_INACTIVE) { 871 sub->tstamp_enabled = tstamp - sub->total_time_enabled; 872 sub->cgrp_defer_enabled = 0; 873 } 874 } 875 } 876 877 /* 878 * Update cpuctx->cgrp so that it is set when first cgroup event is added and 879 * cleared when last cgroup event is removed. 880 */ 881 static inline void 882 list_update_cgroup_event(struct perf_event *event, 883 struct perf_event_context *ctx, bool add) 884 { 885 struct perf_cpu_context *cpuctx; 886 struct list_head *cpuctx_entry; 887 888 if (!is_cgroup_event(event)) 889 return; 890 891 if (add && ctx->nr_cgroups++) 892 return; 893 else if (!add && --ctx->nr_cgroups) 894 return; 895 /* 896 * Because cgroup events are always per-cpu events, 897 * this will always be called from the right CPU. 898 */ 899 cpuctx = __get_cpu_context(ctx); 900 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry; 901 /* cpuctx->cgrp is NULL unless a cgroup event is active in this CPU .*/ 902 if (add) { 903 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list)); 904 if (perf_cgroup_from_task(current, ctx) == event->cgrp) 905 cpuctx->cgrp = event->cgrp; 906 } else { 907 list_del(cpuctx_entry); 908 cpuctx->cgrp = NULL; 909 } 910 } 911 912 #else /* !CONFIG_CGROUP_PERF */ 913 914 static inline bool 915 perf_cgroup_match(struct perf_event *event) 916 { 917 return true; 918 } 919 920 static inline void perf_detach_cgroup(struct perf_event *event) 921 {} 922 923 static inline int is_cgroup_event(struct perf_event *event) 924 { 925 return 0; 926 } 927 928 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event) 929 { 930 return 0; 931 } 932 933 static inline void update_cgrp_time_from_event(struct perf_event *event) 934 { 935 } 936 937 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) 938 { 939 } 940 941 static inline void perf_cgroup_sched_out(struct task_struct *task, 942 struct task_struct *next) 943 { 944 } 945 946 static inline void perf_cgroup_sched_in(struct task_struct *prev, 947 struct task_struct *task) 948 { 949 } 950 951 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event, 952 struct perf_event_attr *attr, 953 struct perf_event *group_leader) 954 { 955 return -EINVAL; 956 } 957 958 static inline void 959 perf_cgroup_set_timestamp(struct task_struct *task, 960 struct perf_event_context *ctx) 961 { 962 } 963 964 void 965 perf_cgroup_switch(struct task_struct *task, struct task_struct *next) 966 { 967 } 968 969 static inline void 970 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) 971 { 972 } 973 974 static inline u64 perf_cgroup_event_time(struct perf_event *event) 975 { 976 return 0; 977 } 978 979 static inline void 980 perf_cgroup_defer_enabled(struct perf_event *event) 981 { 982 } 983 984 static inline void 985 perf_cgroup_mark_enabled(struct perf_event *event, 986 struct perf_event_context *ctx) 987 { 988 } 989 990 static inline void 991 list_update_cgroup_event(struct perf_event *event, 992 struct perf_event_context *ctx, bool add) 993 { 994 } 995 996 #endif 997 998 /* 999 * set default to be dependent on timer tick just 1000 * like original code 1001 */ 1002 #define PERF_CPU_HRTIMER (1000 / HZ) 1003 /* 1004 * function must be called with interrupts disabled 1005 */ 1006 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr) 1007 { 1008 struct perf_cpu_context *cpuctx; 1009 int rotations = 0; 1010 1011 WARN_ON(!irqs_disabled()); 1012 1013 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer); 1014 rotations = perf_rotate_context(cpuctx); 1015 1016 raw_spin_lock(&cpuctx->hrtimer_lock); 1017 if (rotations) 1018 hrtimer_forward_now(hr, cpuctx->hrtimer_interval); 1019 else 1020 cpuctx->hrtimer_active = 0; 1021 raw_spin_unlock(&cpuctx->hrtimer_lock); 1022 1023 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART; 1024 } 1025 1026 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu) 1027 { 1028 struct hrtimer *timer = &cpuctx->hrtimer; 1029 struct pmu *pmu = cpuctx->ctx.pmu; 1030 u64 interval; 1031 1032 /* no multiplexing needed for SW PMU */ 1033 if (pmu->task_ctx_nr == perf_sw_context) 1034 return; 1035 1036 /* 1037 * check default is sane, if not set then force to 1038 * default interval (1/tick) 1039 */ 1040 interval = pmu->hrtimer_interval_ms; 1041 if (interval < 1) 1042 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER; 1043 1044 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval); 1045 1046 raw_spin_lock_init(&cpuctx->hrtimer_lock); 1047 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED); 1048 timer->function = perf_mux_hrtimer_handler; 1049 } 1050 1051 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx) 1052 { 1053 struct hrtimer *timer = &cpuctx->hrtimer; 1054 struct pmu *pmu = cpuctx->ctx.pmu; 1055 unsigned long flags; 1056 1057 /* not for SW PMU */ 1058 if (pmu->task_ctx_nr == perf_sw_context) 1059 return 0; 1060 1061 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags); 1062 if (!cpuctx->hrtimer_active) { 1063 cpuctx->hrtimer_active = 1; 1064 hrtimer_forward_now(timer, cpuctx->hrtimer_interval); 1065 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED); 1066 } 1067 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags); 1068 1069 return 0; 1070 } 1071 1072 void perf_pmu_disable(struct pmu *pmu) 1073 { 1074 int *count = this_cpu_ptr(pmu->pmu_disable_count); 1075 if (!(*count)++) 1076 pmu->pmu_disable(pmu); 1077 } 1078 1079 void perf_pmu_enable(struct pmu *pmu) 1080 { 1081 int *count = this_cpu_ptr(pmu->pmu_disable_count); 1082 if (!--(*count)) 1083 pmu->pmu_enable(pmu); 1084 } 1085 1086 static DEFINE_PER_CPU(struct list_head, active_ctx_list); 1087 1088 /* 1089 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and 1090 * perf_event_task_tick() are fully serialized because they're strictly cpu 1091 * affine and perf_event_ctx{activate,deactivate} are called with IRQs 1092 * disabled, while perf_event_task_tick is called from IRQ context. 1093 */ 1094 static void perf_event_ctx_activate(struct perf_event_context *ctx) 1095 { 1096 struct list_head *head = this_cpu_ptr(&active_ctx_list); 1097 1098 WARN_ON(!irqs_disabled()); 1099 1100 WARN_ON(!list_empty(&ctx->active_ctx_list)); 1101 1102 list_add(&ctx->active_ctx_list, head); 1103 } 1104 1105 static void perf_event_ctx_deactivate(struct perf_event_context *ctx) 1106 { 1107 WARN_ON(!irqs_disabled()); 1108 1109 WARN_ON(list_empty(&ctx->active_ctx_list)); 1110 1111 list_del_init(&ctx->active_ctx_list); 1112 } 1113 1114 static void get_ctx(struct perf_event_context *ctx) 1115 { 1116 WARN_ON(!atomic_inc_not_zero(&ctx->refcount)); 1117 } 1118 1119 static void free_ctx(struct rcu_head *head) 1120 { 1121 struct perf_event_context *ctx; 1122 1123 ctx = container_of(head, struct perf_event_context, rcu_head); 1124 kfree(ctx->task_ctx_data); 1125 kfree(ctx); 1126 } 1127 1128 static void put_ctx(struct perf_event_context *ctx) 1129 { 1130 if (atomic_dec_and_test(&ctx->refcount)) { 1131 if (ctx->parent_ctx) 1132 put_ctx(ctx->parent_ctx); 1133 if (ctx->task && ctx->task != TASK_TOMBSTONE) 1134 put_task_struct(ctx->task); 1135 call_rcu(&ctx->rcu_head, free_ctx); 1136 } 1137 } 1138 1139 /* 1140 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and 1141 * perf_pmu_migrate_context() we need some magic. 1142 * 1143 * Those places that change perf_event::ctx will hold both 1144 * perf_event_ctx::mutex of the 'old' and 'new' ctx value. 1145 * 1146 * Lock ordering is by mutex address. There are two other sites where 1147 * perf_event_context::mutex nests and those are: 1148 * 1149 * - perf_event_exit_task_context() [ child , 0 ] 1150 * perf_event_exit_event() 1151 * put_event() [ parent, 1 ] 1152 * 1153 * - perf_event_init_context() [ parent, 0 ] 1154 * inherit_task_group() 1155 * inherit_group() 1156 * inherit_event() 1157 * perf_event_alloc() 1158 * perf_init_event() 1159 * perf_try_init_event() [ child , 1 ] 1160 * 1161 * While it appears there is an obvious deadlock here -- the parent and child 1162 * nesting levels are inverted between the two. This is in fact safe because 1163 * life-time rules separate them. That is an exiting task cannot fork, and a 1164 * spawning task cannot (yet) exit. 1165 * 1166 * But remember that that these are parent<->child context relations, and 1167 * migration does not affect children, therefore these two orderings should not 1168 * interact. 1169 * 1170 * The change in perf_event::ctx does not affect children (as claimed above) 1171 * because the sys_perf_event_open() case will install a new event and break 1172 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only 1173 * concerned with cpuctx and that doesn't have children. 1174 * 1175 * The places that change perf_event::ctx will issue: 1176 * 1177 * perf_remove_from_context(); 1178 * synchronize_rcu(); 1179 * perf_install_in_context(); 1180 * 1181 * to affect the change. The remove_from_context() + synchronize_rcu() should 1182 * quiesce the event, after which we can install it in the new location. This 1183 * means that only external vectors (perf_fops, prctl) can perturb the event 1184 * while in transit. Therefore all such accessors should also acquire 1185 * perf_event_context::mutex to serialize against this. 1186 * 1187 * However; because event->ctx can change while we're waiting to acquire 1188 * ctx->mutex we must be careful and use the below perf_event_ctx_lock() 1189 * function. 1190 * 1191 * Lock order: 1192 * cred_guard_mutex 1193 * task_struct::perf_event_mutex 1194 * perf_event_context::mutex 1195 * perf_event::child_mutex; 1196 * perf_event_context::lock 1197 * perf_event::mmap_mutex 1198 * mmap_sem 1199 */ 1200 static struct perf_event_context * 1201 perf_event_ctx_lock_nested(struct perf_event *event, int nesting) 1202 { 1203 struct perf_event_context *ctx; 1204 1205 again: 1206 rcu_read_lock(); 1207 ctx = ACCESS_ONCE(event->ctx); 1208 if (!atomic_inc_not_zero(&ctx->refcount)) { 1209 rcu_read_unlock(); 1210 goto again; 1211 } 1212 rcu_read_unlock(); 1213 1214 mutex_lock_nested(&ctx->mutex, nesting); 1215 if (event->ctx != ctx) { 1216 mutex_unlock(&ctx->mutex); 1217 put_ctx(ctx); 1218 goto again; 1219 } 1220 1221 return ctx; 1222 } 1223 1224 static inline struct perf_event_context * 1225 perf_event_ctx_lock(struct perf_event *event) 1226 { 1227 return perf_event_ctx_lock_nested(event, 0); 1228 } 1229 1230 static void perf_event_ctx_unlock(struct perf_event *event, 1231 struct perf_event_context *ctx) 1232 { 1233 mutex_unlock(&ctx->mutex); 1234 put_ctx(ctx); 1235 } 1236 1237 /* 1238 * This must be done under the ctx->lock, such as to serialize against 1239 * context_equiv(), therefore we cannot call put_ctx() since that might end up 1240 * calling scheduler related locks and ctx->lock nests inside those. 1241 */ 1242 static __must_check struct perf_event_context * 1243 unclone_ctx(struct perf_event_context *ctx) 1244 { 1245 struct perf_event_context *parent_ctx = ctx->parent_ctx; 1246 1247 lockdep_assert_held(&ctx->lock); 1248 1249 if (parent_ctx) 1250 ctx->parent_ctx = NULL; 1251 ctx->generation++; 1252 1253 return parent_ctx; 1254 } 1255 1256 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) 1257 { 1258 /* 1259 * only top level events have the pid namespace they were created in 1260 */ 1261 if (event->parent) 1262 event = event->parent; 1263 1264 return task_tgid_nr_ns(p, event->ns); 1265 } 1266 1267 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) 1268 { 1269 /* 1270 * only top level events have the pid namespace they were created in 1271 */ 1272 if (event->parent) 1273 event = event->parent; 1274 1275 return task_pid_nr_ns(p, event->ns); 1276 } 1277 1278 /* 1279 * If we inherit events we want to return the parent event id 1280 * to userspace. 1281 */ 1282 static u64 primary_event_id(struct perf_event *event) 1283 { 1284 u64 id = event->id; 1285 1286 if (event->parent) 1287 id = event->parent->id; 1288 1289 return id; 1290 } 1291 1292 /* 1293 * Get the perf_event_context for a task and lock it. 1294 * 1295 * This has to cope with with the fact that until it is locked, 1296 * the context could get moved to another task. 1297 */ 1298 static struct perf_event_context * 1299 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags) 1300 { 1301 struct perf_event_context *ctx; 1302 1303 retry: 1304 /* 1305 * One of the few rules of preemptible RCU is that one cannot do 1306 * rcu_read_unlock() while holding a scheduler (or nested) lock when 1307 * part of the read side critical section was irqs-enabled -- see 1308 * rcu_read_unlock_special(). 1309 * 1310 * Since ctx->lock nests under rq->lock we must ensure the entire read 1311 * side critical section has interrupts disabled. 1312 */ 1313 local_irq_save(*flags); 1314 rcu_read_lock(); 1315 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]); 1316 if (ctx) { 1317 /* 1318 * If this context is a clone of another, it might 1319 * get swapped for another underneath us by 1320 * perf_event_task_sched_out, though the 1321 * rcu_read_lock() protects us from any context 1322 * getting freed. Lock the context and check if it 1323 * got swapped before we could get the lock, and retry 1324 * if so. If we locked the right context, then it 1325 * can't get swapped on us any more. 1326 */ 1327 raw_spin_lock(&ctx->lock); 1328 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) { 1329 raw_spin_unlock(&ctx->lock); 1330 rcu_read_unlock(); 1331 local_irq_restore(*flags); 1332 goto retry; 1333 } 1334 1335 if (ctx->task == TASK_TOMBSTONE || 1336 !atomic_inc_not_zero(&ctx->refcount)) { 1337 raw_spin_unlock(&ctx->lock); 1338 ctx = NULL; 1339 } else { 1340 WARN_ON_ONCE(ctx->task != task); 1341 } 1342 } 1343 rcu_read_unlock(); 1344 if (!ctx) 1345 local_irq_restore(*flags); 1346 return ctx; 1347 } 1348 1349 /* 1350 * Get the context for a task and increment its pin_count so it 1351 * can't get swapped to another task. This also increments its 1352 * reference count so that the context can't get freed. 1353 */ 1354 static struct perf_event_context * 1355 perf_pin_task_context(struct task_struct *task, int ctxn) 1356 { 1357 struct perf_event_context *ctx; 1358 unsigned long flags; 1359 1360 ctx = perf_lock_task_context(task, ctxn, &flags); 1361 if (ctx) { 1362 ++ctx->pin_count; 1363 raw_spin_unlock_irqrestore(&ctx->lock, flags); 1364 } 1365 return ctx; 1366 } 1367 1368 static void perf_unpin_context(struct perf_event_context *ctx) 1369 { 1370 unsigned long flags; 1371 1372 raw_spin_lock_irqsave(&ctx->lock, flags); 1373 --ctx->pin_count; 1374 raw_spin_unlock_irqrestore(&ctx->lock, flags); 1375 } 1376 1377 /* 1378 * Update the record of the current time in a context. 1379 */ 1380 static void update_context_time(struct perf_event_context *ctx) 1381 { 1382 u64 now = perf_clock(); 1383 1384 ctx->time += now - ctx->timestamp; 1385 ctx->timestamp = now; 1386 } 1387 1388 static u64 perf_event_time(struct perf_event *event) 1389 { 1390 struct perf_event_context *ctx = event->ctx; 1391 1392 if (is_cgroup_event(event)) 1393 return perf_cgroup_event_time(event); 1394 1395 return ctx ? ctx->time : 0; 1396 } 1397 1398 /* 1399 * Update the total_time_enabled and total_time_running fields for a event. 1400 */ 1401 static void update_event_times(struct perf_event *event) 1402 { 1403 struct perf_event_context *ctx = event->ctx; 1404 u64 run_end; 1405 1406 lockdep_assert_held(&ctx->lock); 1407 1408 if (event->state < PERF_EVENT_STATE_INACTIVE || 1409 event->group_leader->state < PERF_EVENT_STATE_INACTIVE) 1410 return; 1411 1412 /* 1413 * in cgroup mode, time_enabled represents 1414 * the time the event was enabled AND active 1415 * tasks were in the monitored cgroup. This is 1416 * independent of the activity of the context as 1417 * there may be a mix of cgroup and non-cgroup events. 1418 * 1419 * That is why we treat cgroup events differently 1420 * here. 1421 */ 1422 if (is_cgroup_event(event)) 1423 run_end = perf_cgroup_event_time(event); 1424 else if (ctx->is_active) 1425 run_end = ctx->time; 1426 else 1427 run_end = event->tstamp_stopped; 1428 1429 event->total_time_enabled = run_end - event->tstamp_enabled; 1430 1431 if (event->state == PERF_EVENT_STATE_INACTIVE) 1432 run_end = event->tstamp_stopped; 1433 else 1434 run_end = perf_event_time(event); 1435 1436 event->total_time_running = run_end - event->tstamp_running; 1437 1438 } 1439 1440 /* 1441 * Update total_time_enabled and total_time_running for all events in a group. 1442 */ 1443 static void update_group_times(struct perf_event *leader) 1444 { 1445 struct perf_event *event; 1446 1447 update_event_times(leader); 1448 list_for_each_entry(event, &leader->sibling_list, group_entry) 1449 update_event_times(event); 1450 } 1451 1452 static enum event_type_t get_event_type(struct perf_event *event) 1453 { 1454 struct perf_event_context *ctx = event->ctx; 1455 enum event_type_t event_type; 1456 1457 lockdep_assert_held(&ctx->lock); 1458 1459 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE; 1460 if (!ctx->task) 1461 event_type |= EVENT_CPU; 1462 1463 return event_type; 1464 } 1465 1466 static struct list_head * 1467 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx) 1468 { 1469 if (event->attr.pinned) 1470 return &ctx->pinned_groups; 1471 else 1472 return &ctx->flexible_groups; 1473 } 1474 1475 /* 1476 * Add a event from the lists for its context. 1477 * Must be called with ctx->mutex and ctx->lock held. 1478 */ 1479 static void 1480 list_add_event(struct perf_event *event, struct perf_event_context *ctx) 1481 { 1482 lockdep_assert_held(&ctx->lock); 1483 1484 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); 1485 event->attach_state |= PERF_ATTACH_CONTEXT; 1486 1487 /* 1488 * If we're a stand alone event or group leader, we go to the context 1489 * list, group events are kept attached to the group so that 1490 * perf_group_detach can, at all times, locate all siblings. 1491 */ 1492 if (event->group_leader == event) { 1493 struct list_head *list; 1494 1495 event->group_caps = event->event_caps; 1496 1497 list = ctx_group_list(event, ctx); 1498 list_add_tail(&event->group_entry, list); 1499 } 1500 1501 list_update_cgroup_event(event, ctx, true); 1502 1503 list_add_rcu(&event->event_entry, &ctx->event_list); 1504 ctx->nr_events++; 1505 if (event->attr.inherit_stat) 1506 ctx->nr_stat++; 1507 1508 ctx->generation++; 1509 } 1510 1511 /* 1512 * Initialize event state based on the perf_event_attr::disabled. 1513 */ 1514 static inline void perf_event__state_init(struct perf_event *event) 1515 { 1516 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF : 1517 PERF_EVENT_STATE_INACTIVE; 1518 } 1519 1520 static void __perf_event_read_size(struct perf_event *event, int nr_siblings) 1521 { 1522 int entry = sizeof(u64); /* value */ 1523 int size = 0; 1524 int nr = 1; 1525 1526 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 1527 size += sizeof(u64); 1528 1529 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 1530 size += sizeof(u64); 1531 1532 if (event->attr.read_format & PERF_FORMAT_ID) 1533 entry += sizeof(u64); 1534 1535 if (event->attr.read_format & PERF_FORMAT_GROUP) { 1536 nr += nr_siblings; 1537 size += sizeof(u64); 1538 } 1539 1540 size += entry * nr; 1541 event->read_size = size; 1542 } 1543 1544 static void __perf_event_header_size(struct perf_event *event, u64 sample_type) 1545 { 1546 struct perf_sample_data *data; 1547 u16 size = 0; 1548 1549 if (sample_type & PERF_SAMPLE_IP) 1550 size += sizeof(data->ip); 1551 1552 if (sample_type & PERF_SAMPLE_ADDR) 1553 size += sizeof(data->addr); 1554 1555 if (sample_type & PERF_SAMPLE_PERIOD) 1556 size += sizeof(data->period); 1557 1558 if (sample_type & PERF_SAMPLE_WEIGHT) 1559 size += sizeof(data->weight); 1560 1561 if (sample_type & PERF_SAMPLE_READ) 1562 size += event->read_size; 1563 1564 if (sample_type & PERF_SAMPLE_DATA_SRC) 1565 size += sizeof(data->data_src.val); 1566 1567 if (sample_type & PERF_SAMPLE_TRANSACTION) 1568 size += sizeof(data->txn); 1569 1570 event->header_size = size; 1571 } 1572 1573 /* 1574 * Called at perf_event creation and when events are attached/detached from a 1575 * group. 1576 */ 1577 static void perf_event__header_size(struct perf_event *event) 1578 { 1579 __perf_event_read_size(event, 1580 event->group_leader->nr_siblings); 1581 __perf_event_header_size(event, event->attr.sample_type); 1582 } 1583 1584 static void perf_event__id_header_size(struct perf_event *event) 1585 { 1586 struct perf_sample_data *data; 1587 u64 sample_type = event->attr.sample_type; 1588 u16 size = 0; 1589 1590 if (sample_type & PERF_SAMPLE_TID) 1591 size += sizeof(data->tid_entry); 1592 1593 if (sample_type & PERF_SAMPLE_TIME) 1594 size += sizeof(data->time); 1595 1596 if (sample_type & PERF_SAMPLE_IDENTIFIER) 1597 size += sizeof(data->id); 1598 1599 if (sample_type & PERF_SAMPLE_ID) 1600 size += sizeof(data->id); 1601 1602 if (sample_type & PERF_SAMPLE_STREAM_ID) 1603 size += sizeof(data->stream_id); 1604 1605 if (sample_type & PERF_SAMPLE_CPU) 1606 size += sizeof(data->cpu_entry); 1607 1608 event->id_header_size = size; 1609 } 1610 1611 static bool perf_event_validate_size(struct perf_event *event) 1612 { 1613 /* 1614 * The values computed here will be over-written when we actually 1615 * attach the event. 1616 */ 1617 __perf_event_read_size(event, event->group_leader->nr_siblings + 1); 1618 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ); 1619 perf_event__id_header_size(event); 1620 1621 /* 1622 * Sum the lot; should not exceed the 64k limit we have on records. 1623 * Conservative limit to allow for callchains and other variable fields. 1624 */ 1625 if (event->read_size + event->header_size + 1626 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024) 1627 return false; 1628 1629 return true; 1630 } 1631 1632 static void perf_group_attach(struct perf_event *event) 1633 { 1634 struct perf_event *group_leader = event->group_leader, *pos; 1635 1636 lockdep_assert_held(&event->ctx->lock); 1637 1638 /* 1639 * We can have double attach due to group movement in perf_event_open. 1640 */ 1641 if (event->attach_state & PERF_ATTACH_GROUP) 1642 return; 1643 1644 event->attach_state |= PERF_ATTACH_GROUP; 1645 1646 if (group_leader == event) 1647 return; 1648 1649 WARN_ON_ONCE(group_leader->ctx != event->ctx); 1650 1651 group_leader->group_caps &= event->event_caps; 1652 1653 list_add_tail(&event->group_entry, &group_leader->sibling_list); 1654 group_leader->nr_siblings++; 1655 1656 perf_event__header_size(group_leader); 1657 1658 list_for_each_entry(pos, &group_leader->sibling_list, group_entry) 1659 perf_event__header_size(pos); 1660 } 1661 1662 /* 1663 * Remove a event from the lists for its context. 1664 * Must be called with ctx->mutex and ctx->lock held. 1665 */ 1666 static void 1667 list_del_event(struct perf_event *event, struct perf_event_context *ctx) 1668 { 1669 WARN_ON_ONCE(event->ctx != ctx); 1670 lockdep_assert_held(&ctx->lock); 1671 1672 /* 1673 * We can have double detach due to exit/hot-unplug + close. 1674 */ 1675 if (!(event->attach_state & PERF_ATTACH_CONTEXT)) 1676 return; 1677 1678 event->attach_state &= ~PERF_ATTACH_CONTEXT; 1679 1680 list_update_cgroup_event(event, ctx, false); 1681 1682 ctx->nr_events--; 1683 if (event->attr.inherit_stat) 1684 ctx->nr_stat--; 1685 1686 list_del_rcu(&event->event_entry); 1687 1688 if (event->group_leader == event) 1689 list_del_init(&event->group_entry); 1690 1691 update_group_times(event); 1692 1693 /* 1694 * If event was in error state, then keep it 1695 * that way, otherwise bogus counts will be 1696 * returned on read(). The only way to get out 1697 * of error state is by explicit re-enabling 1698 * of the event 1699 */ 1700 if (event->state > PERF_EVENT_STATE_OFF) 1701 event->state = PERF_EVENT_STATE_OFF; 1702 1703 ctx->generation++; 1704 } 1705 1706 static void perf_group_detach(struct perf_event *event) 1707 { 1708 struct perf_event *sibling, *tmp; 1709 struct list_head *list = NULL; 1710 1711 lockdep_assert_held(&event->ctx->lock); 1712 1713 /* 1714 * We can have double detach due to exit/hot-unplug + close. 1715 */ 1716 if (!(event->attach_state & PERF_ATTACH_GROUP)) 1717 return; 1718 1719 event->attach_state &= ~PERF_ATTACH_GROUP; 1720 1721 /* 1722 * If this is a sibling, remove it from its group. 1723 */ 1724 if (event->group_leader != event) { 1725 list_del_init(&event->group_entry); 1726 event->group_leader->nr_siblings--; 1727 goto out; 1728 } 1729 1730 if (!list_empty(&event->group_entry)) 1731 list = &event->group_entry; 1732 1733 /* 1734 * If this was a group event with sibling events then 1735 * upgrade the siblings to singleton events by adding them 1736 * to whatever list we are on. 1737 */ 1738 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) { 1739 if (list) 1740 list_move_tail(&sibling->group_entry, list); 1741 sibling->group_leader = sibling; 1742 1743 /* Inherit group flags from the previous leader */ 1744 sibling->group_caps = event->group_caps; 1745 1746 WARN_ON_ONCE(sibling->ctx != event->ctx); 1747 } 1748 1749 out: 1750 perf_event__header_size(event->group_leader); 1751 1752 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry) 1753 perf_event__header_size(tmp); 1754 } 1755 1756 static bool is_orphaned_event(struct perf_event *event) 1757 { 1758 return event->state == PERF_EVENT_STATE_DEAD; 1759 } 1760 1761 static inline int __pmu_filter_match(struct perf_event *event) 1762 { 1763 struct pmu *pmu = event->pmu; 1764 return pmu->filter_match ? pmu->filter_match(event) : 1; 1765 } 1766 1767 /* 1768 * Check whether we should attempt to schedule an event group based on 1769 * PMU-specific filtering. An event group can consist of HW and SW events, 1770 * potentially with a SW leader, so we must check all the filters, to 1771 * determine whether a group is schedulable: 1772 */ 1773 static inline int pmu_filter_match(struct perf_event *event) 1774 { 1775 struct perf_event *child; 1776 1777 if (!__pmu_filter_match(event)) 1778 return 0; 1779 1780 list_for_each_entry(child, &event->sibling_list, group_entry) { 1781 if (!__pmu_filter_match(child)) 1782 return 0; 1783 } 1784 1785 return 1; 1786 } 1787 1788 static inline int 1789 event_filter_match(struct perf_event *event) 1790 { 1791 return (event->cpu == -1 || event->cpu == smp_processor_id()) && 1792 perf_cgroup_match(event) && pmu_filter_match(event); 1793 } 1794 1795 static void 1796 event_sched_out(struct perf_event *event, 1797 struct perf_cpu_context *cpuctx, 1798 struct perf_event_context *ctx) 1799 { 1800 u64 tstamp = perf_event_time(event); 1801 u64 delta; 1802 1803 WARN_ON_ONCE(event->ctx != ctx); 1804 lockdep_assert_held(&ctx->lock); 1805 1806 /* 1807 * An event which could not be activated because of 1808 * filter mismatch still needs to have its timings 1809 * maintained, otherwise bogus information is return 1810 * via read() for time_enabled, time_running: 1811 */ 1812 if (event->state == PERF_EVENT_STATE_INACTIVE && 1813 !event_filter_match(event)) { 1814 delta = tstamp - event->tstamp_stopped; 1815 event->tstamp_running += delta; 1816 event->tstamp_stopped = tstamp; 1817 } 1818 1819 if (event->state != PERF_EVENT_STATE_ACTIVE) 1820 return; 1821 1822 perf_pmu_disable(event->pmu); 1823 1824 event->tstamp_stopped = tstamp; 1825 event->pmu->del(event, 0); 1826 event->oncpu = -1; 1827 event->state = PERF_EVENT_STATE_INACTIVE; 1828 if (event->pending_disable) { 1829 event->pending_disable = 0; 1830 event->state = PERF_EVENT_STATE_OFF; 1831 } 1832 1833 if (!is_software_event(event)) 1834 cpuctx->active_oncpu--; 1835 if (!--ctx->nr_active) 1836 perf_event_ctx_deactivate(ctx); 1837 if (event->attr.freq && event->attr.sample_freq) 1838 ctx->nr_freq--; 1839 if (event->attr.exclusive || !cpuctx->active_oncpu) 1840 cpuctx->exclusive = 0; 1841 1842 perf_pmu_enable(event->pmu); 1843 } 1844 1845 static void 1846 group_sched_out(struct perf_event *group_event, 1847 struct perf_cpu_context *cpuctx, 1848 struct perf_event_context *ctx) 1849 { 1850 struct perf_event *event; 1851 int state = group_event->state; 1852 1853 perf_pmu_disable(ctx->pmu); 1854 1855 event_sched_out(group_event, cpuctx, ctx); 1856 1857 /* 1858 * Schedule out siblings (if any): 1859 */ 1860 list_for_each_entry(event, &group_event->sibling_list, group_entry) 1861 event_sched_out(event, cpuctx, ctx); 1862 1863 perf_pmu_enable(ctx->pmu); 1864 1865 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive) 1866 cpuctx->exclusive = 0; 1867 } 1868 1869 #define DETACH_GROUP 0x01UL 1870 1871 /* 1872 * Cross CPU call to remove a performance event 1873 * 1874 * We disable the event on the hardware level first. After that we 1875 * remove it from the context list. 1876 */ 1877 static void 1878 __perf_remove_from_context(struct perf_event *event, 1879 struct perf_cpu_context *cpuctx, 1880 struct perf_event_context *ctx, 1881 void *info) 1882 { 1883 unsigned long flags = (unsigned long)info; 1884 1885 event_sched_out(event, cpuctx, ctx); 1886 if (flags & DETACH_GROUP) 1887 perf_group_detach(event); 1888 list_del_event(event, ctx); 1889 1890 if (!ctx->nr_events && ctx->is_active) { 1891 ctx->is_active = 0; 1892 if (ctx->task) { 1893 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 1894 cpuctx->task_ctx = NULL; 1895 } 1896 } 1897 } 1898 1899 /* 1900 * Remove the event from a task's (or a CPU's) list of events. 1901 * 1902 * If event->ctx is a cloned context, callers must make sure that 1903 * every task struct that event->ctx->task could possibly point to 1904 * remains valid. This is OK when called from perf_release since 1905 * that only calls us on the top-level context, which can't be a clone. 1906 * When called from perf_event_exit_task, it's OK because the 1907 * context has been detached from its task. 1908 */ 1909 static void perf_remove_from_context(struct perf_event *event, unsigned long flags) 1910 { 1911 struct perf_event_context *ctx = event->ctx; 1912 1913 lockdep_assert_held(&ctx->mutex); 1914 1915 event_function_call(event, __perf_remove_from_context, (void *)flags); 1916 1917 /* 1918 * The above event_function_call() can NO-OP when it hits 1919 * TASK_TOMBSTONE. In that case we must already have been detached 1920 * from the context (by perf_event_exit_event()) but the grouping 1921 * might still be in-tact. 1922 */ 1923 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); 1924 if ((flags & DETACH_GROUP) && 1925 (event->attach_state & PERF_ATTACH_GROUP)) { 1926 /* 1927 * Since in that case we cannot possibly be scheduled, simply 1928 * detach now. 1929 */ 1930 raw_spin_lock_irq(&ctx->lock); 1931 perf_group_detach(event); 1932 raw_spin_unlock_irq(&ctx->lock); 1933 } 1934 } 1935 1936 /* 1937 * Cross CPU call to disable a performance event 1938 */ 1939 static void __perf_event_disable(struct perf_event *event, 1940 struct perf_cpu_context *cpuctx, 1941 struct perf_event_context *ctx, 1942 void *info) 1943 { 1944 if (event->state < PERF_EVENT_STATE_INACTIVE) 1945 return; 1946 1947 update_context_time(ctx); 1948 update_cgrp_time_from_event(event); 1949 update_group_times(event); 1950 if (event == event->group_leader) 1951 group_sched_out(event, cpuctx, ctx); 1952 else 1953 event_sched_out(event, cpuctx, ctx); 1954 event->state = PERF_EVENT_STATE_OFF; 1955 } 1956 1957 /* 1958 * Disable a event. 1959 * 1960 * If event->ctx is a cloned context, callers must make sure that 1961 * every task struct that event->ctx->task could possibly point to 1962 * remains valid. This condition is satisifed when called through 1963 * perf_event_for_each_child or perf_event_for_each because they 1964 * hold the top-level event's child_mutex, so any descendant that 1965 * goes to exit will block in perf_event_exit_event(). 1966 * 1967 * When called from perf_pending_event it's OK because event->ctx 1968 * is the current context on this CPU and preemption is disabled, 1969 * hence we can't get into perf_event_task_sched_out for this context. 1970 */ 1971 static void _perf_event_disable(struct perf_event *event) 1972 { 1973 struct perf_event_context *ctx = event->ctx; 1974 1975 raw_spin_lock_irq(&ctx->lock); 1976 if (event->state <= PERF_EVENT_STATE_OFF) { 1977 raw_spin_unlock_irq(&ctx->lock); 1978 return; 1979 } 1980 raw_spin_unlock_irq(&ctx->lock); 1981 1982 event_function_call(event, __perf_event_disable, NULL); 1983 } 1984 1985 void perf_event_disable_local(struct perf_event *event) 1986 { 1987 event_function_local(event, __perf_event_disable, NULL); 1988 } 1989 1990 /* 1991 * Strictly speaking kernel users cannot create groups and therefore this 1992 * interface does not need the perf_event_ctx_lock() magic. 1993 */ 1994 void perf_event_disable(struct perf_event *event) 1995 { 1996 struct perf_event_context *ctx; 1997 1998 ctx = perf_event_ctx_lock(event); 1999 _perf_event_disable(event); 2000 perf_event_ctx_unlock(event, ctx); 2001 } 2002 EXPORT_SYMBOL_GPL(perf_event_disable); 2003 2004 void perf_event_disable_inatomic(struct perf_event *event) 2005 { 2006 event->pending_disable = 1; 2007 irq_work_queue(&event->pending); 2008 } 2009 2010 static void perf_set_shadow_time(struct perf_event *event, 2011 struct perf_event_context *ctx, 2012 u64 tstamp) 2013 { 2014 /* 2015 * use the correct time source for the time snapshot 2016 * 2017 * We could get by without this by leveraging the 2018 * fact that to get to this function, the caller 2019 * has most likely already called update_context_time() 2020 * and update_cgrp_time_xx() and thus both timestamp 2021 * are identical (or very close). Given that tstamp is, 2022 * already adjusted for cgroup, we could say that: 2023 * tstamp - ctx->timestamp 2024 * is equivalent to 2025 * tstamp - cgrp->timestamp. 2026 * 2027 * Then, in perf_output_read(), the calculation would 2028 * work with no changes because: 2029 * - event is guaranteed scheduled in 2030 * - no scheduled out in between 2031 * - thus the timestamp would be the same 2032 * 2033 * But this is a bit hairy. 2034 * 2035 * So instead, we have an explicit cgroup call to remain 2036 * within the time time source all along. We believe it 2037 * is cleaner and simpler to understand. 2038 */ 2039 if (is_cgroup_event(event)) 2040 perf_cgroup_set_shadow_time(event, tstamp); 2041 else 2042 event->shadow_ctx_time = tstamp - ctx->timestamp; 2043 } 2044 2045 #define MAX_INTERRUPTS (~0ULL) 2046 2047 static void perf_log_throttle(struct perf_event *event, int enable); 2048 static void perf_log_itrace_start(struct perf_event *event); 2049 2050 static int 2051 event_sched_in(struct perf_event *event, 2052 struct perf_cpu_context *cpuctx, 2053 struct perf_event_context *ctx) 2054 { 2055 u64 tstamp = perf_event_time(event); 2056 int ret = 0; 2057 2058 lockdep_assert_held(&ctx->lock); 2059 2060 if (event->state <= PERF_EVENT_STATE_OFF) 2061 return 0; 2062 2063 WRITE_ONCE(event->oncpu, smp_processor_id()); 2064 /* 2065 * Order event::oncpu write to happen before the ACTIVE state 2066 * is visible. 2067 */ 2068 smp_wmb(); 2069 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE); 2070 2071 /* 2072 * Unthrottle events, since we scheduled we might have missed several 2073 * ticks already, also for a heavily scheduling task there is little 2074 * guarantee it'll get a tick in a timely manner. 2075 */ 2076 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) { 2077 perf_log_throttle(event, 1); 2078 event->hw.interrupts = 0; 2079 } 2080 2081 /* 2082 * The new state must be visible before we turn it on in the hardware: 2083 */ 2084 smp_wmb(); 2085 2086 perf_pmu_disable(event->pmu); 2087 2088 perf_set_shadow_time(event, ctx, tstamp); 2089 2090 perf_log_itrace_start(event); 2091 2092 if (event->pmu->add(event, PERF_EF_START)) { 2093 event->state = PERF_EVENT_STATE_INACTIVE; 2094 event->oncpu = -1; 2095 ret = -EAGAIN; 2096 goto out; 2097 } 2098 2099 event->tstamp_running += tstamp - event->tstamp_stopped; 2100 2101 if (!is_software_event(event)) 2102 cpuctx->active_oncpu++; 2103 if (!ctx->nr_active++) 2104 perf_event_ctx_activate(ctx); 2105 if (event->attr.freq && event->attr.sample_freq) 2106 ctx->nr_freq++; 2107 2108 if (event->attr.exclusive) 2109 cpuctx->exclusive = 1; 2110 2111 out: 2112 perf_pmu_enable(event->pmu); 2113 2114 return ret; 2115 } 2116 2117 static int 2118 group_sched_in(struct perf_event *group_event, 2119 struct perf_cpu_context *cpuctx, 2120 struct perf_event_context *ctx) 2121 { 2122 struct perf_event *event, *partial_group = NULL; 2123 struct pmu *pmu = ctx->pmu; 2124 u64 now = ctx->time; 2125 bool simulate = false; 2126 2127 if (group_event->state == PERF_EVENT_STATE_OFF) 2128 return 0; 2129 2130 pmu->start_txn(pmu, PERF_PMU_TXN_ADD); 2131 2132 if (event_sched_in(group_event, cpuctx, ctx)) { 2133 pmu->cancel_txn(pmu); 2134 perf_mux_hrtimer_restart(cpuctx); 2135 return -EAGAIN; 2136 } 2137 2138 /* 2139 * Schedule in siblings as one group (if any): 2140 */ 2141 list_for_each_entry(event, &group_event->sibling_list, group_entry) { 2142 if (event_sched_in(event, cpuctx, ctx)) { 2143 partial_group = event; 2144 goto group_error; 2145 } 2146 } 2147 2148 if (!pmu->commit_txn(pmu)) 2149 return 0; 2150 2151 group_error: 2152 /* 2153 * Groups can be scheduled in as one unit only, so undo any 2154 * partial group before returning: 2155 * The events up to the failed event are scheduled out normally, 2156 * tstamp_stopped will be updated. 2157 * 2158 * The failed events and the remaining siblings need to have 2159 * their timings updated as if they had gone thru event_sched_in() 2160 * and event_sched_out(). This is required to get consistent timings 2161 * across the group. This also takes care of the case where the group 2162 * could never be scheduled by ensuring tstamp_stopped is set to mark 2163 * the time the event was actually stopped, such that time delta 2164 * calculation in update_event_times() is correct. 2165 */ 2166 list_for_each_entry(event, &group_event->sibling_list, group_entry) { 2167 if (event == partial_group) 2168 simulate = true; 2169 2170 if (simulate) { 2171 event->tstamp_running += now - event->tstamp_stopped; 2172 event->tstamp_stopped = now; 2173 } else { 2174 event_sched_out(event, cpuctx, ctx); 2175 } 2176 } 2177 event_sched_out(group_event, cpuctx, ctx); 2178 2179 pmu->cancel_txn(pmu); 2180 2181 perf_mux_hrtimer_restart(cpuctx); 2182 2183 return -EAGAIN; 2184 } 2185 2186 /* 2187 * Work out whether we can put this event group on the CPU now. 2188 */ 2189 static int group_can_go_on(struct perf_event *event, 2190 struct perf_cpu_context *cpuctx, 2191 int can_add_hw) 2192 { 2193 /* 2194 * Groups consisting entirely of software events can always go on. 2195 */ 2196 if (event->group_caps & PERF_EV_CAP_SOFTWARE) 2197 return 1; 2198 /* 2199 * If an exclusive group is already on, no other hardware 2200 * events can go on. 2201 */ 2202 if (cpuctx->exclusive) 2203 return 0; 2204 /* 2205 * If this group is exclusive and there are already 2206 * events on the CPU, it can't go on. 2207 */ 2208 if (event->attr.exclusive && cpuctx->active_oncpu) 2209 return 0; 2210 /* 2211 * Otherwise, try to add it if all previous groups were able 2212 * to go on. 2213 */ 2214 return can_add_hw; 2215 } 2216 2217 static void add_event_to_ctx(struct perf_event *event, 2218 struct perf_event_context *ctx) 2219 { 2220 u64 tstamp = perf_event_time(event); 2221 2222 list_add_event(event, ctx); 2223 perf_group_attach(event); 2224 event->tstamp_enabled = tstamp; 2225 event->tstamp_running = tstamp; 2226 event->tstamp_stopped = tstamp; 2227 } 2228 2229 static void ctx_sched_out(struct perf_event_context *ctx, 2230 struct perf_cpu_context *cpuctx, 2231 enum event_type_t event_type); 2232 static void 2233 ctx_sched_in(struct perf_event_context *ctx, 2234 struct perf_cpu_context *cpuctx, 2235 enum event_type_t event_type, 2236 struct task_struct *task); 2237 2238 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx, 2239 struct perf_event_context *ctx, 2240 enum event_type_t event_type) 2241 { 2242 if (!cpuctx->task_ctx) 2243 return; 2244 2245 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx)) 2246 return; 2247 2248 ctx_sched_out(ctx, cpuctx, event_type); 2249 } 2250 2251 static void perf_event_sched_in(struct perf_cpu_context *cpuctx, 2252 struct perf_event_context *ctx, 2253 struct task_struct *task) 2254 { 2255 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task); 2256 if (ctx) 2257 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task); 2258 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task); 2259 if (ctx) 2260 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task); 2261 } 2262 2263 /* 2264 * We want to maintain the following priority of scheduling: 2265 * - CPU pinned (EVENT_CPU | EVENT_PINNED) 2266 * - task pinned (EVENT_PINNED) 2267 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE) 2268 * - task flexible (EVENT_FLEXIBLE). 2269 * 2270 * In order to avoid unscheduling and scheduling back in everything every 2271 * time an event is added, only do it for the groups of equal priority and 2272 * below. 2273 * 2274 * This can be called after a batch operation on task events, in which case 2275 * event_type is a bit mask of the types of events involved. For CPU events, 2276 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE. 2277 */ 2278 static void ctx_resched(struct perf_cpu_context *cpuctx, 2279 struct perf_event_context *task_ctx, 2280 enum event_type_t event_type) 2281 { 2282 enum event_type_t ctx_event_type = event_type & EVENT_ALL; 2283 bool cpu_event = !!(event_type & EVENT_CPU); 2284 2285 /* 2286 * If pinned groups are involved, flexible groups also need to be 2287 * scheduled out. 2288 */ 2289 if (event_type & EVENT_PINNED) 2290 event_type |= EVENT_FLEXIBLE; 2291 2292 perf_pmu_disable(cpuctx->ctx.pmu); 2293 if (task_ctx) 2294 task_ctx_sched_out(cpuctx, task_ctx, event_type); 2295 2296 /* 2297 * Decide which cpu ctx groups to schedule out based on the types 2298 * of events that caused rescheduling: 2299 * - EVENT_CPU: schedule out corresponding groups; 2300 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups; 2301 * - otherwise, do nothing more. 2302 */ 2303 if (cpu_event) 2304 cpu_ctx_sched_out(cpuctx, ctx_event_type); 2305 else if (ctx_event_type & EVENT_PINNED) 2306 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); 2307 2308 perf_event_sched_in(cpuctx, task_ctx, current); 2309 perf_pmu_enable(cpuctx->ctx.pmu); 2310 } 2311 2312 /* 2313 * Cross CPU call to install and enable a performance event 2314 * 2315 * Very similar to remote_function() + event_function() but cannot assume that 2316 * things like ctx->is_active and cpuctx->task_ctx are set. 2317 */ 2318 static int __perf_install_in_context(void *info) 2319 { 2320 struct perf_event *event = info; 2321 struct perf_event_context *ctx = event->ctx; 2322 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 2323 struct perf_event_context *task_ctx = cpuctx->task_ctx; 2324 bool reprogram = true; 2325 int ret = 0; 2326 2327 raw_spin_lock(&cpuctx->ctx.lock); 2328 if (ctx->task) { 2329 raw_spin_lock(&ctx->lock); 2330 task_ctx = ctx; 2331 2332 reprogram = (ctx->task == current); 2333 2334 /* 2335 * If the task is running, it must be running on this CPU, 2336 * otherwise we cannot reprogram things. 2337 * 2338 * If its not running, we don't care, ctx->lock will 2339 * serialize against it becoming runnable. 2340 */ 2341 if (task_curr(ctx->task) && !reprogram) { 2342 ret = -ESRCH; 2343 goto unlock; 2344 } 2345 2346 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx); 2347 } else if (task_ctx) { 2348 raw_spin_lock(&task_ctx->lock); 2349 } 2350 2351 if (reprogram) { 2352 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 2353 add_event_to_ctx(event, ctx); 2354 ctx_resched(cpuctx, task_ctx, get_event_type(event)); 2355 } else { 2356 add_event_to_ctx(event, ctx); 2357 } 2358 2359 unlock: 2360 perf_ctx_unlock(cpuctx, task_ctx); 2361 2362 return ret; 2363 } 2364 2365 /* 2366 * Attach a performance event to a context. 2367 * 2368 * Very similar to event_function_call, see comment there. 2369 */ 2370 static void 2371 perf_install_in_context(struct perf_event_context *ctx, 2372 struct perf_event *event, 2373 int cpu) 2374 { 2375 struct task_struct *task = READ_ONCE(ctx->task); 2376 2377 lockdep_assert_held(&ctx->mutex); 2378 2379 if (event->cpu != -1) 2380 event->cpu = cpu; 2381 2382 /* 2383 * Ensures that if we can observe event->ctx, both the event and ctx 2384 * will be 'complete'. See perf_iterate_sb_cpu(). 2385 */ 2386 smp_store_release(&event->ctx, ctx); 2387 2388 if (!task) { 2389 cpu_function_call(cpu, __perf_install_in_context, event); 2390 return; 2391 } 2392 2393 /* 2394 * Should not happen, we validate the ctx is still alive before calling. 2395 */ 2396 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) 2397 return; 2398 2399 /* 2400 * Installing events is tricky because we cannot rely on ctx->is_active 2401 * to be set in case this is the nr_events 0 -> 1 transition. 2402 * 2403 * Instead we use task_curr(), which tells us if the task is running. 2404 * However, since we use task_curr() outside of rq::lock, we can race 2405 * against the actual state. This means the result can be wrong. 2406 * 2407 * If we get a false positive, we retry, this is harmless. 2408 * 2409 * If we get a false negative, things are complicated. If we are after 2410 * perf_event_context_sched_in() ctx::lock will serialize us, and the 2411 * value must be correct. If we're before, it doesn't matter since 2412 * perf_event_context_sched_in() will program the counter. 2413 * 2414 * However, this hinges on the remote context switch having observed 2415 * our task->perf_event_ctxp[] store, such that it will in fact take 2416 * ctx::lock in perf_event_context_sched_in(). 2417 * 2418 * We do this by task_function_call(), if the IPI fails to hit the task 2419 * we know any future context switch of task must see the 2420 * perf_event_ctpx[] store. 2421 */ 2422 2423 /* 2424 * This smp_mb() orders the task->perf_event_ctxp[] store with the 2425 * task_cpu() load, such that if the IPI then does not find the task 2426 * running, a future context switch of that task must observe the 2427 * store. 2428 */ 2429 smp_mb(); 2430 again: 2431 if (!task_function_call(task, __perf_install_in_context, event)) 2432 return; 2433 2434 raw_spin_lock_irq(&ctx->lock); 2435 task = ctx->task; 2436 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) { 2437 /* 2438 * Cannot happen because we already checked above (which also 2439 * cannot happen), and we hold ctx->mutex, which serializes us 2440 * against perf_event_exit_task_context(). 2441 */ 2442 raw_spin_unlock_irq(&ctx->lock); 2443 return; 2444 } 2445 /* 2446 * If the task is not running, ctx->lock will avoid it becoming so, 2447 * thus we can safely install the event. 2448 */ 2449 if (task_curr(task)) { 2450 raw_spin_unlock_irq(&ctx->lock); 2451 goto again; 2452 } 2453 add_event_to_ctx(event, ctx); 2454 raw_spin_unlock_irq(&ctx->lock); 2455 } 2456 2457 /* 2458 * Put a event into inactive state and update time fields. 2459 * Enabling the leader of a group effectively enables all 2460 * the group members that aren't explicitly disabled, so we 2461 * have to update their ->tstamp_enabled also. 2462 * Note: this works for group members as well as group leaders 2463 * since the non-leader members' sibling_lists will be empty. 2464 */ 2465 static void __perf_event_mark_enabled(struct perf_event *event) 2466 { 2467 struct perf_event *sub; 2468 u64 tstamp = perf_event_time(event); 2469 2470 event->state = PERF_EVENT_STATE_INACTIVE; 2471 event->tstamp_enabled = tstamp - event->total_time_enabled; 2472 list_for_each_entry(sub, &event->sibling_list, group_entry) { 2473 if (sub->state >= PERF_EVENT_STATE_INACTIVE) 2474 sub->tstamp_enabled = tstamp - sub->total_time_enabled; 2475 } 2476 } 2477 2478 /* 2479 * Cross CPU call to enable a performance event 2480 */ 2481 static void __perf_event_enable(struct perf_event *event, 2482 struct perf_cpu_context *cpuctx, 2483 struct perf_event_context *ctx, 2484 void *info) 2485 { 2486 struct perf_event *leader = event->group_leader; 2487 struct perf_event_context *task_ctx; 2488 2489 if (event->state >= PERF_EVENT_STATE_INACTIVE || 2490 event->state <= PERF_EVENT_STATE_ERROR) 2491 return; 2492 2493 if (ctx->is_active) 2494 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 2495 2496 __perf_event_mark_enabled(event); 2497 2498 if (!ctx->is_active) 2499 return; 2500 2501 if (!event_filter_match(event)) { 2502 if (is_cgroup_event(event)) 2503 perf_cgroup_defer_enabled(event); 2504 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current); 2505 return; 2506 } 2507 2508 /* 2509 * If the event is in a group and isn't the group leader, 2510 * then don't put it on unless the group is on. 2511 */ 2512 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) { 2513 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current); 2514 return; 2515 } 2516 2517 task_ctx = cpuctx->task_ctx; 2518 if (ctx->task) 2519 WARN_ON_ONCE(task_ctx != ctx); 2520 2521 ctx_resched(cpuctx, task_ctx, get_event_type(event)); 2522 } 2523 2524 /* 2525 * Enable a event. 2526 * 2527 * If event->ctx is a cloned context, callers must make sure that 2528 * every task struct that event->ctx->task could possibly point to 2529 * remains valid. This condition is satisfied when called through 2530 * perf_event_for_each_child or perf_event_for_each as described 2531 * for perf_event_disable. 2532 */ 2533 static void _perf_event_enable(struct perf_event *event) 2534 { 2535 struct perf_event_context *ctx = event->ctx; 2536 2537 raw_spin_lock_irq(&ctx->lock); 2538 if (event->state >= PERF_EVENT_STATE_INACTIVE || 2539 event->state < PERF_EVENT_STATE_ERROR) { 2540 raw_spin_unlock_irq(&ctx->lock); 2541 return; 2542 } 2543 2544 /* 2545 * If the event is in error state, clear that first. 2546 * 2547 * That way, if we see the event in error state below, we know that it 2548 * has gone back into error state, as distinct from the task having 2549 * been scheduled away before the cross-call arrived. 2550 */ 2551 if (event->state == PERF_EVENT_STATE_ERROR) 2552 event->state = PERF_EVENT_STATE_OFF; 2553 raw_spin_unlock_irq(&ctx->lock); 2554 2555 event_function_call(event, __perf_event_enable, NULL); 2556 } 2557 2558 /* 2559 * See perf_event_disable(); 2560 */ 2561 void perf_event_enable(struct perf_event *event) 2562 { 2563 struct perf_event_context *ctx; 2564 2565 ctx = perf_event_ctx_lock(event); 2566 _perf_event_enable(event); 2567 perf_event_ctx_unlock(event, ctx); 2568 } 2569 EXPORT_SYMBOL_GPL(perf_event_enable); 2570 2571 struct stop_event_data { 2572 struct perf_event *event; 2573 unsigned int restart; 2574 }; 2575 2576 static int __perf_event_stop(void *info) 2577 { 2578 struct stop_event_data *sd = info; 2579 struct perf_event *event = sd->event; 2580 2581 /* if it's already INACTIVE, do nothing */ 2582 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) 2583 return 0; 2584 2585 /* matches smp_wmb() in event_sched_in() */ 2586 smp_rmb(); 2587 2588 /* 2589 * There is a window with interrupts enabled before we get here, 2590 * so we need to check again lest we try to stop another CPU's event. 2591 */ 2592 if (READ_ONCE(event->oncpu) != smp_processor_id()) 2593 return -EAGAIN; 2594 2595 event->pmu->stop(event, PERF_EF_UPDATE); 2596 2597 /* 2598 * May race with the actual stop (through perf_pmu_output_stop()), 2599 * but it is only used for events with AUX ring buffer, and such 2600 * events will refuse to restart because of rb::aux_mmap_count==0, 2601 * see comments in perf_aux_output_begin(). 2602 * 2603 * Since this is happening on a event-local CPU, no trace is lost 2604 * while restarting. 2605 */ 2606 if (sd->restart) 2607 event->pmu->start(event, 0); 2608 2609 return 0; 2610 } 2611 2612 static int perf_event_stop(struct perf_event *event, int restart) 2613 { 2614 struct stop_event_data sd = { 2615 .event = event, 2616 .restart = restart, 2617 }; 2618 int ret = 0; 2619 2620 do { 2621 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) 2622 return 0; 2623 2624 /* matches smp_wmb() in event_sched_in() */ 2625 smp_rmb(); 2626 2627 /* 2628 * We only want to restart ACTIVE events, so if the event goes 2629 * inactive here (event->oncpu==-1), there's nothing more to do; 2630 * fall through with ret==-ENXIO. 2631 */ 2632 ret = cpu_function_call(READ_ONCE(event->oncpu), 2633 __perf_event_stop, &sd); 2634 } while (ret == -EAGAIN); 2635 2636 return ret; 2637 } 2638 2639 /* 2640 * In order to contain the amount of racy and tricky in the address filter 2641 * configuration management, it is a two part process: 2642 * 2643 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below, 2644 * we update the addresses of corresponding vmas in 2645 * event::addr_filters_offs array and bump the event::addr_filters_gen; 2646 * (p2) when an event is scheduled in (pmu::add), it calls 2647 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync() 2648 * if the generation has changed since the previous call. 2649 * 2650 * If (p1) happens while the event is active, we restart it to force (p2). 2651 * 2652 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on 2653 * pre-existing mappings, called once when new filters arrive via SET_FILTER 2654 * ioctl; 2655 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly 2656 * registered mapping, called for every new mmap(), with mm::mmap_sem down 2657 * for reading; 2658 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process 2659 * of exec. 2660 */ 2661 void perf_event_addr_filters_sync(struct perf_event *event) 2662 { 2663 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 2664 2665 if (!has_addr_filter(event)) 2666 return; 2667 2668 raw_spin_lock(&ifh->lock); 2669 if (event->addr_filters_gen != event->hw.addr_filters_gen) { 2670 event->pmu->addr_filters_sync(event); 2671 event->hw.addr_filters_gen = event->addr_filters_gen; 2672 } 2673 raw_spin_unlock(&ifh->lock); 2674 } 2675 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync); 2676 2677 static int _perf_event_refresh(struct perf_event *event, int refresh) 2678 { 2679 /* 2680 * not supported on inherited events 2681 */ 2682 if (event->attr.inherit || !is_sampling_event(event)) 2683 return -EINVAL; 2684 2685 atomic_add(refresh, &event->event_limit); 2686 _perf_event_enable(event); 2687 2688 return 0; 2689 } 2690 2691 /* 2692 * See perf_event_disable() 2693 */ 2694 int perf_event_refresh(struct perf_event *event, int refresh) 2695 { 2696 struct perf_event_context *ctx; 2697 int ret; 2698 2699 ctx = perf_event_ctx_lock(event); 2700 ret = _perf_event_refresh(event, refresh); 2701 perf_event_ctx_unlock(event, ctx); 2702 2703 return ret; 2704 } 2705 EXPORT_SYMBOL_GPL(perf_event_refresh); 2706 2707 static void ctx_sched_out(struct perf_event_context *ctx, 2708 struct perf_cpu_context *cpuctx, 2709 enum event_type_t event_type) 2710 { 2711 int is_active = ctx->is_active; 2712 struct perf_event *event; 2713 2714 lockdep_assert_held(&ctx->lock); 2715 2716 if (likely(!ctx->nr_events)) { 2717 /* 2718 * See __perf_remove_from_context(). 2719 */ 2720 WARN_ON_ONCE(ctx->is_active); 2721 if (ctx->task) 2722 WARN_ON_ONCE(cpuctx->task_ctx); 2723 return; 2724 } 2725 2726 ctx->is_active &= ~event_type; 2727 if (!(ctx->is_active & EVENT_ALL)) 2728 ctx->is_active = 0; 2729 2730 if (ctx->task) { 2731 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 2732 if (!ctx->is_active) 2733 cpuctx->task_ctx = NULL; 2734 } 2735 2736 /* 2737 * Always update time if it was set; not only when it changes. 2738 * Otherwise we can 'forget' to update time for any but the last 2739 * context we sched out. For example: 2740 * 2741 * ctx_sched_out(.event_type = EVENT_FLEXIBLE) 2742 * ctx_sched_out(.event_type = EVENT_PINNED) 2743 * 2744 * would only update time for the pinned events. 2745 */ 2746 if (is_active & EVENT_TIME) { 2747 /* update (and stop) ctx time */ 2748 update_context_time(ctx); 2749 update_cgrp_time_from_cpuctx(cpuctx); 2750 } 2751 2752 is_active ^= ctx->is_active; /* changed bits */ 2753 2754 if (!ctx->nr_active || !(is_active & EVENT_ALL)) 2755 return; 2756 2757 perf_pmu_disable(ctx->pmu); 2758 if (is_active & EVENT_PINNED) { 2759 list_for_each_entry(event, &ctx->pinned_groups, group_entry) 2760 group_sched_out(event, cpuctx, ctx); 2761 } 2762 2763 if (is_active & EVENT_FLEXIBLE) { 2764 list_for_each_entry(event, &ctx->flexible_groups, group_entry) 2765 group_sched_out(event, cpuctx, ctx); 2766 } 2767 perf_pmu_enable(ctx->pmu); 2768 } 2769 2770 /* 2771 * Test whether two contexts are equivalent, i.e. whether they have both been 2772 * cloned from the same version of the same context. 2773 * 2774 * Equivalence is measured using a generation number in the context that is 2775 * incremented on each modification to it; see unclone_ctx(), list_add_event() 2776 * and list_del_event(). 2777 */ 2778 static int context_equiv(struct perf_event_context *ctx1, 2779 struct perf_event_context *ctx2) 2780 { 2781 lockdep_assert_held(&ctx1->lock); 2782 lockdep_assert_held(&ctx2->lock); 2783 2784 /* Pinning disables the swap optimization */ 2785 if (ctx1->pin_count || ctx2->pin_count) 2786 return 0; 2787 2788 /* If ctx1 is the parent of ctx2 */ 2789 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen) 2790 return 1; 2791 2792 /* If ctx2 is the parent of ctx1 */ 2793 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation) 2794 return 1; 2795 2796 /* 2797 * If ctx1 and ctx2 have the same parent; we flatten the parent 2798 * hierarchy, see perf_event_init_context(). 2799 */ 2800 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx && 2801 ctx1->parent_gen == ctx2->parent_gen) 2802 return 1; 2803 2804 /* Unmatched */ 2805 return 0; 2806 } 2807 2808 static void __perf_event_sync_stat(struct perf_event *event, 2809 struct perf_event *next_event) 2810 { 2811 u64 value; 2812 2813 if (!event->attr.inherit_stat) 2814 return; 2815 2816 /* 2817 * Update the event value, we cannot use perf_event_read() 2818 * because we're in the middle of a context switch and have IRQs 2819 * disabled, which upsets smp_call_function_single(), however 2820 * we know the event must be on the current CPU, therefore we 2821 * don't need to use it. 2822 */ 2823 switch (event->state) { 2824 case PERF_EVENT_STATE_ACTIVE: 2825 event->pmu->read(event); 2826 /* fall-through */ 2827 2828 case PERF_EVENT_STATE_INACTIVE: 2829 update_event_times(event); 2830 break; 2831 2832 default: 2833 break; 2834 } 2835 2836 /* 2837 * In order to keep per-task stats reliable we need to flip the event 2838 * values when we flip the contexts. 2839 */ 2840 value = local64_read(&next_event->count); 2841 value = local64_xchg(&event->count, value); 2842 local64_set(&next_event->count, value); 2843 2844 swap(event->total_time_enabled, next_event->total_time_enabled); 2845 swap(event->total_time_running, next_event->total_time_running); 2846 2847 /* 2848 * Since we swizzled the values, update the user visible data too. 2849 */ 2850 perf_event_update_userpage(event); 2851 perf_event_update_userpage(next_event); 2852 } 2853 2854 static void perf_event_sync_stat(struct perf_event_context *ctx, 2855 struct perf_event_context *next_ctx) 2856 { 2857 struct perf_event *event, *next_event; 2858 2859 if (!ctx->nr_stat) 2860 return; 2861 2862 update_context_time(ctx); 2863 2864 event = list_first_entry(&ctx->event_list, 2865 struct perf_event, event_entry); 2866 2867 next_event = list_first_entry(&next_ctx->event_list, 2868 struct perf_event, event_entry); 2869 2870 while (&event->event_entry != &ctx->event_list && 2871 &next_event->event_entry != &next_ctx->event_list) { 2872 2873 __perf_event_sync_stat(event, next_event); 2874 2875 event = list_next_entry(event, event_entry); 2876 next_event = list_next_entry(next_event, event_entry); 2877 } 2878 } 2879 2880 static void perf_event_context_sched_out(struct task_struct *task, int ctxn, 2881 struct task_struct *next) 2882 { 2883 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn]; 2884 struct perf_event_context *next_ctx; 2885 struct perf_event_context *parent, *next_parent; 2886 struct perf_cpu_context *cpuctx; 2887 int do_switch = 1; 2888 2889 if (likely(!ctx)) 2890 return; 2891 2892 cpuctx = __get_cpu_context(ctx); 2893 if (!cpuctx->task_ctx) 2894 return; 2895 2896 rcu_read_lock(); 2897 next_ctx = next->perf_event_ctxp[ctxn]; 2898 if (!next_ctx) 2899 goto unlock; 2900 2901 parent = rcu_dereference(ctx->parent_ctx); 2902 next_parent = rcu_dereference(next_ctx->parent_ctx); 2903 2904 /* If neither context have a parent context; they cannot be clones. */ 2905 if (!parent && !next_parent) 2906 goto unlock; 2907 2908 if (next_parent == ctx || next_ctx == parent || next_parent == parent) { 2909 /* 2910 * Looks like the two contexts are clones, so we might be 2911 * able to optimize the context switch. We lock both 2912 * contexts and check that they are clones under the 2913 * lock (including re-checking that neither has been 2914 * uncloned in the meantime). It doesn't matter which 2915 * order we take the locks because no other cpu could 2916 * be trying to lock both of these tasks. 2917 */ 2918 raw_spin_lock(&ctx->lock); 2919 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING); 2920 if (context_equiv(ctx, next_ctx)) { 2921 WRITE_ONCE(ctx->task, next); 2922 WRITE_ONCE(next_ctx->task, task); 2923 2924 swap(ctx->task_ctx_data, next_ctx->task_ctx_data); 2925 2926 /* 2927 * RCU_INIT_POINTER here is safe because we've not 2928 * modified the ctx and the above modification of 2929 * ctx->task and ctx->task_ctx_data are immaterial 2930 * since those values are always verified under 2931 * ctx->lock which we're now holding. 2932 */ 2933 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx); 2934 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx); 2935 2936 do_switch = 0; 2937 2938 perf_event_sync_stat(ctx, next_ctx); 2939 } 2940 raw_spin_unlock(&next_ctx->lock); 2941 raw_spin_unlock(&ctx->lock); 2942 } 2943 unlock: 2944 rcu_read_unlock(); 2945 2946 if (do_switch) { 2947 raw_spin_lock(&ctx->lock); 2948 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL); 2949 raw_spin_unlock(&ctx->lock); 2950 } 2951 } 2952 2953 static DEFINE_PER_CPU(struct list_head, sched_cb_list); 2954 2955 void perf_sched_cb_dec(struct pmu *pmu) 2956 { 2957 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 2958 2959 this_cpu_dec(perf_sched_cb_usages); 2960 2961 if (!--cpuctx->sched_cb_usage) 2962 list_del(&cpuctx->sched_cb_entry); 2963 } 2964 2965 2966 void perf_sched_cb_inc(struct pmu *pmu) 2967 { 2968 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 2969 2970 if (!cpuctx->sched_cb_usage++) 2971 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list)); 2972 2973 this_cpu_inc(perf_sched_cb_usages); 2974 } 2975 2976 /* 2977 * This function provides the context switch callback to the lower code 2978 * layer. It is invoked ONLY when the context switch callback is enabled. 2979 * 2980 * This callback is relevant even to per-cpu events; for example multi event 2981 * PEBS requires this to provide PID/TID information. This requires we flush 2982 * all queued PEBS records before we context switch to a new task. 2983 */ 2984 static void perf_pmu_sched_task(struct task_struct *prev, 2985 struct task_struct *next, 2986 bool sched_in) 2987 { 2988 struct perf_cpu_context *cpuctx; 2989 struct pmu *pmu; 2990 2991 if (prev == next) 2992 return; 2993 2994 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) { 2995 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */ 2996 2997 if (WARN_ON_ONCE(!pmu->sched_task)) 2998 continue; 2999 3000 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 3001 perf_pmu_disable(pmu); 3002 3003 pmu->sched_task(cpuctx->task_ctx, sched_in); 3004 3005 perf_pmu_enable(pmu); 3006 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 3007 } 3008 } 3009 3010 static void perf_event_switch(struct task_struct *task, 3011 struct task_struct *next_prev, bool sched_in); 3012 3013 #define for_each_task_context_nr(ctxn) \ 3014 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++) 3015 3016 /* 3017 * Called from scheduler to remove the events of the current task, 3018 * with interrupts disabled. 3019 * 3020 * We stop each event and update the event value in event->count. 3021 * 3022 * This does not protect us against NMI, but disable() 3023 * sets the disabled bit in the control field of event _before_ 3024 * accessing the event control register. If a NMI hits, then it will 3025 * not restart the event. 3026 */ 3027 void __perf_event_task_sched_out(struct task_struct *task, 3028 struct task_struct *next) 3029 { 3030 int ctxn; 3031 3032 if (__this_cpu_read(perf_sched_cb_usages)) 3033 perf_pmu_sched_task(task, next, false); 3034 3035 if (atomic_read(&nr_switch_events)) 3036 perf_event_switch(task, next, false); 3037 3038 for_each_task_context_nr(ctxn) 3039 perf_event_context_sched_out(task, ctxn, next); 3040 3041 /* 3042 * if cgroup events exist on this CPU, then we need 3043 * to check if we have to switch out PMU state. 3044 * cgroup event are system-wide mode only 3045 */ 3046 if (atomic_read(this_cpu_ptr(&perf_cgroup_events))) 3047 perf_cgroup_sched_out(task, next); 3048 } 3049 3050 /* 3051 * Called with IRQs disabled 3052 */ 3053 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, 3054 enum event_type_t event_type) 3055 { 3056 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type); 3057 } 3058 3059 static void 3060 ctx_pinned_sched_in(struct perf_event_context *ctx, 3061 struct perf_cpu_context *cpuctx) 3062 { 3063 struct perf_event *event; 3064 3065 list_for_each_entry(event, &ctx->pinned_groups, group_entry) { 3066 if (event->state <= PERF_EVENT_STATE_OFF) 3067 continue; 3068 if (!event_filter_match(event)) 3069 continue; 3070 3071 /* may need to reset tstamp_enabled */ 3072 if (is_cgroup_event(event)) 3073 perf_cgroup_mark_enabled(event, ctx); 3074 3075 if (group_can_go_on(event, cpuctx, 1)) 3076 group_sched_in(event, cpuctx, ctx); 3077 3078 /* 3079 * If this pinned group hasn't been scheduled, 3080 * put it in error state. 3081 */ 3082 if (event->state == PERF_EVENT_STATE_INACTIVE) { 3083 update_group_times(event); 3084 event->state = PERF_EVENT_STATE_ERROR; 3085 } 3086 } 3087 } 3088 3089 static void 3090 ctx_flexible_sched_in(struct perf_event_context *ctx, 3091 struct perf_cpu_context *cpuctx) 3092 { 3093 struct perf_event *event; 3094 int can_add_hw = 1; 3095 3096 list_for_each_entry(event, &ctx->flexible_groups, group_entry) { 3097 /* Ignore events in OFF or ERROR state */ 3098 if (event->state <= PERF_EVENT_STATE_OFF) 3099 continue; 3100 /* 3101 * Listen to the 'cpu' scheduling filter constraint 3102 * of events: 3103 */ 3104 if (!event_filter_match(event)) 3105 continue; 3106 3107 /* may need to reset tstamp_enabled */ 3108 if (is_cgroup_event(event)) 3109 perf_cgroup_mark_enabled(event, ctx); 3110 3111 if (group_can_go_on(event, cpuctx, can_add_hw)) { 3112 if (group_sched_in(event, cpuctx, ctx)) 3113 can_add_hw = 0; 3114 } 3115 } 3116 } 3117 3118 static void 3119 ctx_sched_in(struct perf_event_context *ctx, 3120 struct perf_cpu_context *cpuctx, 3121 enum event_type_t event_type, 3122 struct task_struct *task) 3123 { 3124 int is_active = ctx->is_active; 3125 u64 now; 3126 3127 lockdep_assert_held(&ctx->lock); 3128 3129 if (likely(!ctx->nr_events)) 3130 return; 3131 3132 ctx->is_active |= (event_type | EVENT_TIME); 3133 if (ctx->task) { 3134 if (!is_active) 3135 cpuctx->task_ctx = ctx; 3136 else 3137 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 3138 } 3139 3140 is_active ^= ctx->is_active; /* changed bits */ 3141 3142 if (is_active & EVENT_TIME) { 3143 /* start ctx time */ 3144 now = perf_clock(); 3145 ctx->timestamp = now; 3146 perf_cgroup_set_timestamp(task, ctx); 3147 } 3148 3149 /* 3150 * First go through the list and put on any pinned groups 3151 * in order to give them the best chance of going on. 3152 */ 3153 if (is_active & EVENT_PINNED) 3154 ctx_pinned_sched_in(ctx, cpuctx); 3155 3156 /* Then walk through the lower prio flexible groups */ 3157 if (is_active & EVENT_FLEXIBLE) 3158 ctx_flexible_sched_in(ctx, cpuctx); 3159 } 3160 3161 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, 3162 enum event_type_t event_type, 3163 struct task_struct *task) 3164 { 3165 struct perf_event_context *ctx = &cpuctx->ctx; 3166 3167 ctx_sched_in(ctx, cpuctx, event_type, task); 3168 } 3169 3170 static void perf_event_context_sched_in(struct perf_event_context *ctx, 3171 struct task_struct *task) 3172 { 3173 struct perf_cpu_context *cpuctx; 3174 3175 cpuctx = __get_cpu_context(ctx); 3176 if (cpuctx->task_ctx == ctx) 3177 return; 3178 3179 perf_ctx_lock(cpuctx, ctx); 3180 perf_pmu_disable(ctx->pmu); 3181 /* 3182 * We want to keep the following priority order: 3183 * cpu pinned (that don't need to move), task pinned, 3184 * cpu flexible, task flexible. 3185 * 3186 * However, if task's ctx is not carrying any pinned 3187 * events, no need to flip the cpuctx's events around. 3188 */ 3189 if (!list_empty(&ctx->pinned_groups)) 3190 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); 3191 perf_event_sched_in(cpuctx, ctx, task); 3192 perf_pmu_enable(ctx->pmu); 3193 perf_ctx_unlock(cpuctx, ctx); 3194 } 3195 3196 /* 3197 * Called from scheduler to add the events of the current task 3198 * with interrupts disabled. 3199 * 3200 * We restore the event value and then enable it. 3201 * 3202 * This does not protect us against NMI, but enable() 3203 * sets the enabled bit in the control field of event _before_ 3204 * accessing the event control register. If a NMI hits, then it will 3205 * keep the event running. 3206 */ 3207 void __perf_event_task_sched_in(struct task_struct *prev, 3208 struct task_struct *task) 3209 { 3210 struct perf_event_context *ctx; 3211 int ctxn; 3212 3213 /* 3214 * If cgroup events exist on this CPU, then we need to check if we have 3215 * to switch in PMU state; cgroup event are system-wide mode only. 3216 * 3217 * Since cgroup events are CPU events, we must schedule these in before 3218 * we schedule in the task events. 3219 */ 3220 if (atomic_read(this_cpu_ptr(&perf_cgroup_events))) 3221 perf_cgroup_sched_in(prev, task); 3222 3223 for_each_task_context_nr(ctxn) { 3224 ctx = task->perf_event_ctxp[ctxn]; 3225 if (likely(!ctx)) 3226 continue; 3227 3228 perf_event_context_sched_in(ctx, task); 3229 } 3230 3231 if (atomic_read(&nr_switch_events)) 3232 perf_event_switch(task, prev, true); 3233 3234 if (__this_cpu_read(perf_sched_cb_usages)) 3235 perf_pmu_sched_task(prev, task, true); 3236 } 3237 3238 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count) 3239 { 3240 u64 frequency = event->attr.sample_freq; 3241 u64 sec = NSEC_PER_SEC; 3242 u64 divisor, dividend; 3243 3244 int count_fls, nsec_fls, frequency_fls, sec_fls; 3245 3246 count_fls = fls64(count); 3247 nsec_fls = fls64(nsec); 3248 frequency_fls = fls64(frequency); 3249 sec_fls = 30; 3250 3251 /* 3252 * We got @count in @nsec, with a target of sample_freq HZ 3253 * the target period becomes: 3254 * 3255 * @count * 10^9 3256 * period = ------------------- 3257 * @nsec * sample_freq 3258 * 3259 */ 3260 3261 /* 3262 * Reduce accuracy by one bit such that @a and @b converge 3263 * to a similar magnitude. 3264 */ 3265 #define REDUCE_FLS(a, b) \ 3266 do { \ 3267 if (a##_fls > b##_fls) { \ 3268 a >>= 1; \ 3269 a##_fls--; \ 3270 } else { \ 3271 b >>= 1; \ 3272 b##_fls--; \ 3273 } \ 3274 } while (0) 3275 3276 /* 3277 * Reduce accuracy until either term fits in a u64, then proceed with 3278 * the other, so that finally we can do a u64/u64 division. 3279 */ 3280 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) { 3281 REDUCE_FLS(nsec, frequency); 3282 REDUCE_FLS(sec, count); 3283 } 3284 3285 if (count_fls + sec_fls > 64) { 3286 divisor = nsec * frequency; 3287 3288 while (count_fls + sec_fls > 64) { 3289 REDUCE_FLS(count, sec); 3290 divisor >>= 1; 3291 } 3292 3293 dividend = count * sec; 3294 } else { 3295 dividend = count * sec; 3296 3297 while (nsec_fls + frequency_fls > 64) { 3298 REDUCE_FLS(nsec, frequency); 3299 dividend >>= 1; 3300 } 3301 3302 divisor = nsec * frequency; 3303 } 3304 3305 if (!divisor) 3306 return dividend; 3307 3308 return div64_u64(dividend, divisor); 3309 } 3310 3311 static DEFINE_PER_CPU(int, perf_throttled_count); 3312 static DEFINE_PER_CPU(u64, perf_throttled_seq); 3313 3314 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable) 3315 { 3316 struct hw_perf_event *hwc = &event->hw; 3317 s64 period, sample_period; 3318 s64 delta; 3319 3320 period = perf_calculate_period(event, nsec, count); 3321 3322 delta = (s64)(period - hwc->sample_period); 3323 delta = (delta + 7) / 8; /* low pass filter */ 3324 3325 sample_period = hwc->sample_period + delta; 3326 3327 if (!sample_period) 3328 sample_period = 1; 3329 3330 hwc->sample_period = sample_period; 3331 3332 if (local64_read(&hwc->period_left) > 8*sample_period) { 3333 if (disable) 3334 event->pmu->stop(event, PERF_EF_UPDATE); 3335 3336 local64_set(&hwc->period_left, 0); 3337 3338 if (disable) 3339 event->pmu->start(event, PERF_EF_RELOAD); 3340 } 3341 } 3342 3343 /* 3344 * combine freq adjustment with unthrottling to avoid two passes over the 3345 * events. At the same time, make sure, having freq events does not change 3346 * the rate of unthrottling as that would introduce bias. 3347 */ 3348 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx, 3349 int needs_unthr) 3350 { 3351 struct perf_event *event; 3352 struct hw_perf_event *hwc; 3353 u64 now, period = TICK_NSEC; 3354 s64 delta; 3355 3356 /* 3357 * only need to iterate over all events iff: 3358 * - context have events in frequency mode (needs freq adjust) 3359 * - there are events to unthrottle on this cpu 3360 */ 3361 if (!(ctx->nr_freq || needs_unthr)) 3362 return; 3363 3364 raw_spin_lock(&ctx->lock); 3365 perf_pmu_disable(ctx->pmu); 3366 3367 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 3368 if (event->state != PERF_EVENT_STATE_ACTIVE) 3369 continue; 3370 3371 if (!event_filter_match(event)) 3372 continue; 3373 3374 perf_pmu_disable(event->pmu); 3375 3376 hwc = &event->hw; 3377 3378 if (hwc->interrupts == MAX_INTERRUPTS) { 3379 hwc->interrupts = 0; 3380 perf_log_throttle(event, 1); 3381 event->pmu->start(event, 0); 3382 } 3383 3384 if (!event->attr.freq || !event->attr.sample_freq) 3385 goto next; 3386 3387 /* 3388 * stop the event and update event->count 3389 */ 3390 event->pmu->stop(event, PERF_EF_UPDATE); 3391 3392 now = local64_read(&event->count); 3393 delta = now - hwc->freq_count_stamp; 3394 hwc->freq_count_stamp = now; 3395 3396 /* 3397 * restart the event 3398 * reload only if value has changed 3399 * we have stopped the event so tell that 3400 * to perf_adjust_period() to avoid stopping it 3401 * twice. 3402 */ 3403 if (delta > 0) 3404 perf_adjust_period(event, period, delta, false); 3405 3406 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0); 3407 next: 3408 perf_pmu_enable(event->pmu); 3409 } 3410 3411 perf_pmu_enable(ctx->pmu); 3412 raw_spin_unlock(&ctx->lock); 3413 } 3414 3415 /* 3416 * Round-robin a context's events: 3417 */ 3418 static void rotate_ctx(struct perf_event_context *ctx) 3419 { 3420 /* 3421 * Rotate the first entry last of non-pinned groups. Rotation might be 3422 * disabled by the inheritance code. 3423 */ 3424 if (!ctx->rotate_disable) 3425 list_rotate_left(&ctx->flexible_groups); 3426 } 3427 3428 static int perf_rotate_context(struct perf_cpu_context *cpuctx) 3429 { 3430 struct perf_event_context *ctx = NULL; 3431 int rotate = 0; 3432 3433 if (cpuctx->ctx.nr_events) { 3434 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active) 3435 rotate = 1; 3436 } 3437 3438 ctx = cpuctx->task_ctx; 3439 if (ctx && ctx->nr_events) { 3440 if (ctx->nr_events != ctx->nr_active) 3441 rotate = 1; 3442 } 3443 3444 if (!rotate) 3445 goto done; 3446 3447 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 3448 perf_pmu_disable(cpuctx->ctx.pmu); 3449 3450 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); 3451 if (ctx) 3452 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE); 3453 3454 rotate_ctx(&cpuctx->ctx); 3455 if (ctx) 3456 rotate_ctx(ctx); 3457 3458 perf_event_sched_in(cpuctx, ctx, current); 3459 3460 perf_pmu_enable(cpuctx->ctx.pmu); 3461 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 3462 done: 3463 3464 return rotate; 3465 } 3466 3467 void perf_event_task_tick(void) 3468 { 3469 struct list_head *head = this_cpu_ptr(&active_ctx_list); 3470 struct perf_event_context *ctx, *tmp; 3471 int throttled; 3472 3473 WARN_ON(!irqs_disabled()); 3474 3475 __this_cpu_inc(perf_throttled_seq); 3476 throttled = __this_cpu_xchg(perf_throttled_count, 0); 3477 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); 3478 3479 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list) 3480 perf_adjust_freq_unthr_context(ctx, throttled); 3481 } 3482 3483 static int event_enable_on_exec(struct perf_event *event, 3484 struct perf_event_context *ctx) 3485 { 3486 if (!event->attr.enable_on_exec) 3487 return 0; 3488 3489 event->attr.enable_on_exec = 0; 3490 if (event->state >= PERF_EVENT_STATE_INACTIVE) 3491 return 0; 3492 3493 __perf_event_mark_enabled(event); 3494 3495 return 1; 3496 } 3497 3498 /* 3499 * Enable all of a task's events that have been marked enable-on-exec. 3500 * This expects task == current. 3501 */ 3502 static void perf_event_enable_on_exec(int ctxn) 3503 { 3504 struct perf_event_context *ctx, *clone_ctx = NULL; 3505 enum event_type_t event_type = 0; 3506 struct perf_cpu_context *cpuctx; 3507 struct perf_event *event; 3508 unsigned long flags; 3509 int enabled = 0; 3510 3511 local_irq_save(flags); 3512 ctx = current->perf_event_ctxp[ctxn]; 3513 if (!ctx || !ctx->nr_events) 3514 goto out; 3515 3516 cpuctx = __get_cpu_context(ctx); 3517 perf_ctx_lock(cpuctx, ctx); 3518 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 3519 list_for_each_entry(event, &ctx->event_list, event_entry) { 3520 enabled |= event_enable_on_exec(event, ctx); 3521 event_type |= get_event_type(event); 3522 } 3523 3524 /* 3525 * Unclone and reschedule this context if we enabled any event. 3526 */ 3527 if (enabled) { 3528 clone_ctx = unclone_ctx(ctx); 3529 ctx_resched(cpuctx, ctx, event_type); 3530 } else { 3531 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current); 3532 } 3533 perf_ctx_unlock(cpuctx, ctx); 3534 3535 out: 3536 local_irq_restore(flags); 3537 3538 if (clone_ctx) 3539 put_ctx(clone_ctx); 3540 } 3541 3542 struct perf_read_data { 3543 struct perf_event *event; 3544 bool group; 3545 int ret; 3546 }; 3547 3548 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu) 3549 { 3550 u16 local_pkg, event_pkg; 3551 3552 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) { 3553 int local_cpu = smp_processor_id(); 3554 3555 event_pkg = topology_physical_package_id(event_cpu); 3556 local_pkg = topology_physical_package_id(local_cpu); 3557 3558 if (event_pkg == local_pkg) 3559 return local_cpu; 3560 } 3561 3562 return event_cpu; 3563 } 3564 3565 /* 3566 * Cross CPU call to read the hardware event 3567 */ 3568 static void __perf_event_read(void *info) 3569 { 3570 struct perf_read_data *data = info; 3571 struct perf_event *sub, *event = data->event; 3572 struct perf_event_context *ctx = event->ctx; 3573 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 3574 struct pmu *pmu = event->pmu; 3575 3576 /* 3577 * If this is a task context, we need to check whether it is 3578 * the current task context of this cpu. If not it has been 3579 * scheduled out before the smp call arrived. In that case 3580 * event->count would have been updated to a recent sample 3581 * when the event was scheduled out. 3582 */ 3583 if (ctx->task && cpuctx->task_ctx != ctx) 3584 return; 3585 3586 raw_spin_lock(&ctx->lock); 3587 if (ctx->is_active) { 3588 update_context_time(ctx); 3589 update_cgrp_time_from_event(event); 3590 } 3591 3592 update_event_times(event); 3593 if (event->state != PERF_EVENT_STATE_ACTIVE) 3594 goto unlock; 3595 3596 if (!data->group) { 3597 pmu->read(event); 3598 data->ret = 0; 3599 goto unlock; 3600 } 3601 3602 pmu->start_txn(pmu, PERF_PMU_TXN_READ); 3603 3604 pmu->read(event); 3605 3606 list_for_each_entry(sub, &event->sibling_list, group_entry) { 3607 update_event_times(sub); 3608 if (sub->state == PERF_EVENT_STATE_ACTIVE) { 3609 /* 3610 * Use sibling's PMU rather than @event's since 3611 * sibling could be on different (eg: software) PMU. 3612 */ 3613 sub->pmu->read(sub); 3614 } 3615 } 3616 3617 data->ret = pmu->commit_txn(pmu); 3618 3619 unlock: 3620 raw_spin_unlock(&ctx->lock); 3621 } 3622 3623 static inline u64 perf_event_count(struct perf_event *event) 3624 { 3625 if (event->pmu->count) 3626 return event->pmu->count(event); 3627 3628 return __perf_event_count(event); 3629 } 3630 3631 /* 3632 * NMI-safe method to read a local event, that is an event that 3633 * is: 3634 * - either for the current task, or for this CPU 3635 * - does not have inherit set, for inherited task events 3636 * will not be local and we cannot read them atomically 3637 * - must not have a pmu::count method 3638 */ 3639 u64 perf_event_read_local(struct perf_event *event) 3640 { 3641 unsigned long flags; 3642 u64 val; 3643 3644 /* 3645 * Disabling interrupts avoids all counter scheduling (context 3646 * switches, timer based rotation and IPIs). 3647 */ 3648 local_irq_save(flags); 3649 3650 /* If this is a per-task event, it must be for current */ 3651 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) && 3652 event->hw.target != current); 3653 3654 /* If this is a per-CPU event, it must be for this CPU */ 3655 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) && 3656 event->cpu != smp_processor_id()); 3657 3658 /* 3659 * It must not be an event with inherit set, we cannot read 3660 * all child counters from atomic context. 3661 */ 3662 WARN_ON_ONCE(event->attr.inherit); 3663 3664 /* 3665 * It must not have a pmu::count method, those are not 3666 * NMI safe. 3667 */ 3668 WARN_ON_ONCE(event->pmu->count); 3669 3670 /* 3671 * If the event is currently on this CPU, its either a per-task event, 3672 * or local to this CPU. Furthermore it means its ACTIVE (otherwise 3673 * oncpu == -1). 3674 */ 3675 if (event->oncpu == smp_processor_id()) 3676 event->pmu->read(event); 3677 3678 val = local64_read(&event->count); 3679 local_irq_restore(flags); 3680 3681 return val; 3682 } 3683 3684 static int perf_event_read(struct perf_event *event, bool group) 3685 { 3686 int event_cpu, ret = 0; 3687 3688 /* 3689 * If event is enabled and currently active on a CPU, update the 3690 * value in the event structure: 3691 */ 3692 if (event->state == PERF_EVENT_STATE_ACTIVE) { 3693 struct perf_read_data data = { 3694 .event = event, 3695 .group = group, 3696 .ret = 0, 3697 }; 3698 3699 event_cpu = READ_ONCE(event->oncpu); 3700 if ((unsigned)event_cpu >= nr_cpu_ids) 3701 return 0; 3702 3703 preempt_disable(); 3704 event_cpu = __perf_event_read_cpu(event, event_cpu); 3705 3706 /* 3707 * Purposely ignore the smp_call_function_single() return 3708 * value. 3709 * 3710 * If event_cpu isn't a valid CPU it means the event got 3711 * scheduled out and that will have updated the event count. 3712 * 3713 * Therefore, either way, we'll have an up-to-date event count 3714 * after this. 3715 */ 3716 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1); 3717 preempt_enable(); 3718 ret = data.ret; 3719 } else if (event->state == PERF_EVENT_STATE_INACTIVE) { 3720 struct perf_event_context *ctx = event->ctx; 3721 unsigned long flags; 3722 3723 raw_spin_lock_irqsave(&ctx->lock, flags); 3724 /* 3725 * may read while context is not active 3726 * (e.g., thread is blocked), in that case 3727 * we cannot update context time 3728 */ 3729 if (ctx->is_active) { 3730 update_context_time(ctx); 3731 update_cgrp_time_from_event(event); 3732 } 3733 if (group) 3734 update_group_times(event); 3735 else 3736 update_event_times(event); 3737 raw_spin_unlock_irqrestore(&ctx->lock, flags); 3738 } 3739 3740 return ret; 3741 } 3742 3743 /* 3744 * Initialize the perf_event context in a task_struct: 3745 */ 3746 static void __perf_event_init_context(struct perf_event_context *ctx) 3747 { 3748 raw_spin_lock_init(&ctx->lock); 3749 mutex_init(&ctx->mutex); 3750 INIT_LIST_HEAD(&ctx->active_ctx_list); 3751 INIT_LIST_HEAD(&ctx->pinned_groups); 3752 INIT_LIST_HEAD(&ctx->flexible_groups); 3753 INIT_LIST_HEAD(&ctx->event_list); 3754 atomic_set(&ctx->refcount, 1); 3755 } 3756 3757 static struct perf_event_context * 3758 alloc_perf_context(struct pmu *pmu, struct task_struct *task) 3759 { 3760 struct perf_event_context *ctx; 3761 3762 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL); 3763 if (!ctx) 3764 return NULL; 3765 3766 __perf_event_init_context(ctx); 3767 if (task) { 3768 ctx->task = task; 3769 get_task_struct(task); 3770 } 3771 ctx->pmu = pmu; 3772 3773 return ctx; 3774 } 3775 3776 static struct task_struct * 3777 find_lively_task_by_vpid(pid_t vpid) 3778 { 3779 struct task_struct *task; 3780 3781 rcu_read_lock(); 3782 if (!vpid) 3783 task = current; 3784 else 3785 task = find_task_by_vpid(vpid); 3786 if (task) 3787 get_task_struct(task); 3788 rcu_read_unlock(); 3789 3790 if (!task) 3791 return ERR_PTR(-ESRCH); 3792 3793 return task; 3794 } 3795 3796 /* 3797 * Returns a matching context with refcount and pincount. 3798 */ 3799 static struct perf_event_context * 3800 find_get_context(struct pmu *pmu, struct task_struct *task, 3801 struct perf_event *event) 3802 { 3803 struct perf_event_context *ctx, *clone_ctx = NULL; 3804 struct perf_cpu_context *cpuctx; 3805 void *task_ctx_data = NULL; 3806 unsigned long flags; 3807 int ctxn, err; 3808 int cpu = event->cpu; 3809 3810 if (!task) { 3811 /* Must be root to operate on a CPU event: */ 3812 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN)) 3813 return ERR_PTR(-EACCES); 3814 3815 /* 3816 * We could be clever and allow to attach a event to an 3817 * offline CPU and activate it when the CPU comes up, but 3818 * that's for later. 3819 */ 3820 if (!cpu_online(cpu)) 3821 return ERR_PTR(-ENODEV); 3822 3823 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 3824 ctx = &cpuctx->ctx; 3825 get_ctx(ctx); 3826 ++ctx->pin_count; 3827 3828 return ctx; 3829 } 3830 3831 err = -EINVAL; 3832 ctxn = pmu->task_ctx_nr; 3833 if (ctxn < 0) 3834 goto errout; 3835 3836 if (event->attach_state & PERF_ATTACH_TASK_DATA) { 3837 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL); 3838 if (!task_ctx_data) { 3839 err = -ENOMEM; 3840 goto errout; 3841 } 3842 } 3843 3844 retry: 3845 ctx = perf_lock_task_context(task, ctxn, &flags); 3846 if (ctx) { 3847 clone_ctx = unclone_ctx(ctx); 3848 ++ctx->pin_count; 3849 3850 if (task_ctx_data && !ctx->task_ctx_data) { 3851 ctx->task_ctx_data = task_ctx_data; 3852 task_ctx_data = NULL; 3853 } 3854 raw_spin_unlock_irqrestore(&ctx->lock, flags); 3855 3856 if (clone_ctx) 3857 put_ctx(clone_ctx); 3858 } else { 3859 ctx = alloc_perf_context(pmu, task); 3860 err = -ENOMEM; 3861 if (!ctx) 3862 goto errout; 3863 3864 if (task_ctx_data) { 3865 ctx->task_ctx_data = task_ctx_data; 3866 task_ctx_data = NULL; 3867 } 3868 3869 err = 0; 3870 mutex_lock(&task->perf_event_mutex); 3871 /* 3872 * If it has already passed perf_event_exit_task(). 3873 * we must see PF_EXITING, it takes this mutex too. 3874 */ 3875 if (task->flags & PF_EXITING) 3876 err = -ESRCH; 3877 else if (task->perf_event_ctxp[ctxn]) 3878 err = -EAGAIN; 3879 else { 3880 get_ctx(ctx); 3881 ++ctx->pin_count; 3882 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx); 3883 } 3884 mutex_unlock(&task->perf_event_mutex); 3885 3886 if (unlikely(err)) { 3887 put_ctx(ctx); 3888 3889 if (err == -EAGAIN) 3890 goto retry; 3891 goto errout; 3892 } 3893 } 3894 3895 kfree(task_ctx_data); 3896 return ctx; 3897 3898 errout: 3899 kfree(task_ctx_data); 3900 return ERR_PTR(err); 3901 } 3902 3903 static void perf_event_free_filter(struct perf_event *event); 3904 static void perf_event_free_bpf_prog(struct perf_event *event); 3905 3906 static void free_event_rcu(struct rcu_head *head) 3907 { 3908 struct perf_event *event; 3909 3910 event = container_of(head, struct perf_event, rcu_head); 3911 if (event->ns) 3912 put_pid_ns(event->ns); 3913 perf_event_free_filter(event); 3914 kfree(event); 3915 } 3916 3917 static void ring_buffer_attach(struct perf_event *event, 3918 struct ring_buffer *rb); 3919 3920 static void detach_sb_event(struct perf_event *event) 3921 { 3922 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu); 3923 3924 raw_spin_lock(&pel->lock); 3925 list_del_rcu(&event->sb_list); 3926 raw_spin_unlock(&pel->lock); 3927 } 3928 3929 static bool is_sb_event(struct perf_event *event) 3930 { 3931 struct perf_event_attr *attr = &event->attr; 3932 3933 if (event->parent) 3934 return false; 3935 3936 if (event->attach_state & PERF_ATTACH_TASK) 3937 return false; 3938 3939 if (attr->mmap || attr->mmap_data || attr->mmap2 || 3940 attr->comm || attr->comm_exec || 3941 attr->task || 3942 attr->context_switch) 3943 return true; 3944 return false; 3945 } 3946 3947 static void unaccount_pmu_sb_event(struct perf_event *event) 3948 { 3949 if (is_sb_event(event)) 3950 detach_sb_event(event); 3951 } 3952 3953 static void unaccount_event_cpu(struct perf_event *event, int cpu) 3954 { 3955 if (event->parent) 3956 return; 3957 3958 if (is_cgroup_event(event)) 3959 atomic_dec(&per_cpu(perf_cgroup_events, cpu)); 3960 } 3961 3962 #ifdef CONFIG_NO_HZ_FULL 3963 static DEFINE_SPINLOCK(nr_freq_lock); 3964 #endif 3965 3966 static void unaccount_freq_event_nohz(void) 3967 { 3968 #ifdef CONFIG_NO_HZ_FULL 3969 spin_lock(&nr_freq_lock); 3970 if (atomic_dec_and_test(&nr_freq_events)) 3971 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS); 3972 spin_unlock(&nr_freq_lock); 3973 #endif 3974 } 3975 3976 static void unaccount_freq_event(void) 3977 { 3978 if (tick_nohz_full_enabled()) 3979 unaccount_freq_event_nohz(); 3980 else 3981 atomic_dec(&nr_freq_events); 3982 } 3983 3984 static void unaccount_event(struct perf_event *event) 3985 { 3986 bool dec = false; 3987 3988 if (event->parent) 3989 return; 3990 3991 if (event->attach_state & PERF_ATTACH_TASK) 3992 dec = true; 3993 if (event->attr.mmap || event->attr.mmap_data) 3994 atomic_dec(&nr_mmap_events); 3995 if (event->attr.comm) 3996 atomic_dec(&nr_comm_events); 3997 if (event->attr.namespaces) 3998 atomic_dec(&nr_namespaces_events); 3999 if (event->attr.task) 4000 atomic_dec(&nr_task_events); 4001 if (event->attr.freq) 4002 unaccount_freq_event(); 4003 if (event->attr.context_switch) { 4004 dec = true; 4005 atomic_dec(&nr_switch_events); 4006 } 4007 if (is_cgroup_event(event)) 4008 dec = true; 4009 if (has_branch_stack(event)) 4010 dec = true; 4011 4012 if (dec) { 4013 if (!atomic_add_unless(&perf_sched_count, -1, 1)) 4014 schedule_delayed_work(&perf_sched_work, HZ); 4015 } 4016 4017 unaccount_event_cpu(event, event->cpu); 4018 4019 unaccount_pmu_sb_event(event); 4020 } 4021 4022 static void perf_sched_delayed(struct work_struct *work) 4023 { 4024 mutex_lock(&perf_sched_mutex); 4025 if (atomic_dec_and_test(&perf_sched_count)) 4026 static_branch_disable(&perf_sched_events); 4027 mutex_unlock(&perf_sched_mutex); 4028 } 4029 4030 /* 4031 * The following implement mutual exclusion of events on "exclusive" pmus 4032 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled 4033 * at a time, so we disallow creating events that might conflict, namely: 4034 * 4035 * 1) cpu-wide events in the presence of per-task events, 4036 * 2) per-task events in the presence of cpu-wide events, 4037 * 3) two matching events on the same context. 4038 * 4039 * The former two cases are handled in the allocation path (perf_event_alloc(), 4040 * _free_event()), the latter -- before the first perf_install_in_context(). 4041 */ 4042 static int exclusive_event_init(struct perf_event *event) 4043 { 4044 struct pmu *pmu = event->pmu; 4045 4046 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE)) 4047 return 0; 4048 4049 /* 4050 * Prevent co-existence of per-task and cpu-wide events on the 4051 * same exclusive pmu. 4052 * 4053 * Negative pmu::exclusive_cnt means there are cpu-wide 4054 * events on this "exclusive" pmu, positive means there are 4055 * per-task events. 4056 * 4057 * Since this is called in perf_event_alloc() path, event::ctx 4058 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK 4059 * to mean "per-task event", because unlike other attach states it 4060 * never gets cleared. 4061 */ 4062 if (event->attach_state & PERF_ATTACH_TASK) { 4063 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt)) 4064 return -EBUSY; 4065 } else { 4066 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt)) 4067 return -EBUSY; 4068 } 4069 4070 return 0; 4071 } 4072 4073 static void exclusive_event_destroy(struct perf_event *event) 4074 { 4075 struct pmu *pmu = event->pmu; 4076 4077 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE)) 4078 return; 4079 4080 /* see comment in exclusive_event_init() */ 4081 if (event->attach_state & PERF_ATTACH_TASK) 4082 atomic_dec(&pmu->exclusive_cnt); 4083 else 4084 atomic_inc(&pmu->exclusive_cnt); 4085 } 4086 4087 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2) 4088 { 4089 if ((e1->pmu == e2->pmu) && 4090 (e1->cpu == e2->cpu || 4091 e1->cpu == -1 || 4092 e2->cpu == -1)) 4093 return true; 4094 return false; 4095 } 4096 4097 /* Called under the same ctx::mutex as perf_install_in_context() */ 4098 static bool exclusive_event_installable(struct perf_event *event, 4099 struct perf_event_context *ctx) 4100 { 4101 struct perf_event *iter_event; 4102 struct pmu *pmu = event->pmu; 4103 4104 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE)) 4105 return true; 4106 4107 list_for_each_entry(iter_event, &ctx->event_list, event_entry) { 4108 if (exclusive_event_match(iter_event, event)) 4109 return false; 4110 } 4111 4112 return true; 4113 } 4114 4115 static void perf_addr_filters_splice(struct perf_event *event, 4116 struct list_head *head); 4117 4118 static void _free_event(struct perf_event *event) 4119 { 4120 irq_work_sync(&event->pending); 4121 4122 unaccount_event(event); 4123 4124 if (event->rb) { 4125 /* 4126 * Can happen when we close an event with re-directed output. 4127 * 4128 * Since we have a 0 refcount, perf_mmap_close() will skip 4129 * over us; possibly making our ring_buffer_put() the last. 4130 */ 4131 mutex_lock(&event->mmap_mutex); 4132 ring_buffer_attach(event, NULL); 4133 mutex_unlock(&event->mmap_mutex); 4134 } 4135 4136 if (is_cgroup_event(event)) 4137 perf_detach_cgroup(event); 4138 4139 if (!event->parent) { 4140 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) 4141 put_callchain_buffers(); 4142 } 4143 4144 perf_event_free_bpf_prog(event); 4145 perf_addr_filters_splice(event, NULL); 4146 kfree(event->addr_filters_offs); 4147 4148 if (event->destroy) 4149 event->destroy(event); 4150 4151 if (event->ctx) 4152 put_ctx(event->ctx); 4153 4154 exclusive_event_destroy(event); 4155 module_put(event->pmu->module); 4156 4157 call_rcu(&event->rcu_head, free_event_rcu); 4158 } 4159 4160 /* 4161 * Used to free events which have a known refcount of 1, such as in error paths 4162 * where the event isn't exposed yet and inherited events. 4163 */ 4164 static void free_event(struct perf_event *event) 4165 { 4166 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1, 4167 "unexpected event refcount: %ld; ptr=%p\n", 4168 atomic_long_read(&event->refcount), event)) { 4169 /* leak to avoid use-after-free */ 4170 return; 4171 } 4172 4173 _free_event(event); 4174 } 4175 4176 /* 4177 * Remove user event from the owner task. 4178 */ 4179 static void perf_remove_from_owner(struct perf_event *event) 4180 { 4181 struct task_struct *owner; 4182 4183 rcu_read_lock(); 4184 /* 4185 * Matches the smp_store_release() in perf_event_exit_task(). If we 4186 * observe !owner it means the list deletion is complete and we can 4187 * indeed free this event, otherwise we need to serialize on 4188 * owner->perf_event_mutex. 4189 */ 4190 owner = lockless_dereference(event->owner); 4191 if (owner) { 4192 /* 4193 * Since delayed_put_task_struct() also drops the last 4194 * task reference we can safely take a new reference 4195 * while holding the rcu_read_lock(). 4196 */ 4197 get_task_struct(owner); 4198 } 4199 rcu_read_unlock(); 4200 4201 if (owner) { 4202 /* 4203 * If we're here through perf_event_exit_task() we're already 4204 * holding ctx->mutex which would be an inversion wrt. the 4205 * normal lock order. 4206 * 4207 * However we can safely take this lock because its the child 4208 * ctx->mutex. 4209 */ 4210 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING); 4211 4212 /* 4213 * We have to re-check the event->owner field, if it is cleared 4214 * we raced with perf_event_exit_task(), acquiring the mutex 4215 * ensured they're done, and we can proceed with freeing the 4216 * event. 4217 */ 4218 if (event->owner) { 4219 list_del_init(&event->owner_entry); 4220 smp_store_release(&event->owner, NULL); 4221 } 4222 mutex_unlock(&owner->perf_event_mutex); 4223 put_task_struct(owner); 4224 } 4225 } 4226 4227 static void put_event(struct perf_event *event) 4228 { 4229 if (!atomic_long_dec_and_test(&event->refcount)) 4230 return; 4231 4232 _free_event(event); 4233 } 4234 4235 /* 4236 * Kill an event dead; while event:refcount will preserve the event 4237 * object, it will not preserve its functionality. Once the last 'user' 4238 * gives up the object, we'll destroy the thing. 4239 */ 4240 int perf_event_release_kernel(struct perf_event *event) 4241 { 4242 struct perf_event_context *ctx = event->ctx; 4243 struct perf_event *child, *tmp; 4244 4245 /* 4246 * If we got here through err_file: fput(event_file); we will not have 4247 * attached to a context yet. 4248 */ 4249 if (!ctx) { 4250 WARN_ON_ONCE(event->attach_state & 4251 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP)); 4252 goto no_ctx; 4253 } 4254 4255 if (!is_kernel_event(event)) 4256 perf_remove_from_owner(event); 4257 4258 ctx = perf_event_ctx_lock(event); 4259 WARN_ON_ONCE(ctx->parent_ctx); 4260 perf_remove_from_context(event, DETACH_GROUP); 4261 4262 raw_spin_lock_irq(&ctx->lock); 4263 /* 4264 * Mark this event as STATE_DEAD, there is no external reference to it 4265 * anymore. 4266 * 4267 * Anybody acquiring event->child_mutex after the below loop _must_ 4268 * also see this, most importantly inherit_event() which will avoid 4269 * placing more children on the list. 4270 * 4271 * Thus this guarantees that we will in fact observe and kill _ALL_ 4272 * child events. 4273 */ 4274 event->state = PERF_EVENT_STATE_DEAD; 4275 raw_spin_unlock_irq(&ctx->lock); 4276 4277 perf_event_ctx_unlock(event, ctx); 4278 4279 again: 4280 mutex_lock(&event->child_mutex); 4281 list_for_each_entry(child, &event->child_list, child_list) { 4282 4283 /* 4284 * Cannot change, child events are not migrated, see the 4285 * comment with perf_event_ctx_lock_nested(). 4286 */ 4287 ctx = lockless_dereference(child->ctx); 4288 /* 4289 * Since child_mutex nests inside ctx::mutex, we must jump 4290 * through hoops. We start by grabbing a reference on the ctx. 4291 * 4292 * Since the event cannot get freed while we hold the 4293 * child_mutex, the context must also exist and have a !0 4294 * reference count. 4295 */ 4296 get_ctx(ctx); 4297 4298 /* 4299 * Now that we have a ctx ref, we can drop child_mutex, and 4300 * acquire ctx::mutex without fear of it going away. Then we 4301 * can re-acquire child_mutex. 4302 */ 4303 mutex_unlock(&event->child_mutex); 4304 mutex_lock(&ctx->mutex); 4305 mutex_lock(&event->child_mutex); 4306 4307 /* 4308 * Now that we hold ctx::mutex and child_mutex, revalidate our 4309 * state, if child is still the first entry, it didn't get freed 4310 * and we can continue doing so. 4311 */ 4312 tmp = list_first_entry_or_null(&event->child_list, 4313 struct perf_event, child_list); 4314 if (tmp == child) { 4315 perf_remove_from_context(child, DETACH_GROUP); 4316 list_del(&child->child_list); 4317 free_event(child); 4318 /* 4319 * This matches the refcount bump in inherit_event(); 4320 * this can't be the last reference. 4321 */ 4322 put_event(event); 4323 } 4324 4325 mutex_unlock(&event->child_mutex); 4326 mutex_unlock(&ctx->mutex); 4327 put_ctx(ctx); 4328 goto again; 4329 } 4330 mutex_unlock(&event->child_mutex); 4331 4332 no_ctx: 4333 put_event(event); /* Must be the 'last' reference */ 4334 return 0; 4335 } 4336 EXPORT_SYMBOL_GPL(perf_event_release_kernel); 4337 4338 /* 4339 * Called when the last reference to the file is gone. 4340 */ 4341 static int perf_release(struct inode *inode, struct file *file) 4342 { 4343 perf_event_release_kernel(file->private_data); 4344 return 0; 4345 } 4346 4347 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) 4348 { 4349 struct perf_event *child; 4350 u64 total = 0; 4351 4352 *enabled = 0; 4353 *running = 0; 4354 4355 mutex_lock(&event->child_mutex); 4356 4357 (void)perf_event_read(event, false); 4358 total += perf_event_count(event); 4359 4360 *enabled += event->total_time_enabled + 4361 atomic64_read(&event->child_total_time_enabled); 4362 *running += event->total_time_running + 4363 atomic64_read(&event->child_total_time_running); 4364 4365 list_for_each_entry(child, &event->child_list, child_list) { 4366 (void)perf_event_read(child, false); 4367 total += perf_event_count(child); 4368 *enabled += child->total_time_enabled; 4369 *running += child->total_time_running; 4370 } 4371 mutex_unlock(&event->child_mutex); 4372 4373 return total; 4374 } 4375 EXPORT_SYMBOL_GPL(perf_event_read_value); 4376 4377 static int __perf_read_group_add(struct perf_event *leader, 4378 u64 read_format, u64 *values) 4379 { 4380 struct perf_event *sub; 4381 int n = 1; /* skip @nr */ 4382 int ret; 4383 4384 ret = perf_event_read(leader, true); 4385 if (ret) 4386 return ret; 4387 4388 /* 4389 * Since we co-schedule groups, {enabled,running} times of siblings 4390 * will be identical to those of the leader, so we only publish one 4391 * set. 4392 */ 4393 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { 4394 values[n++] += leader->total_time_enabled + 4395 atomic64_read(&leader->child_total_time_enabled); 4396 } 4397 4398 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { 4399 values[n++] += leader->total_time_running + 4400 atomic64_read(&leader->child_total_time_running); 4401 } 4402 4403 /* 4404 * Write {count,id} tuples for every sibling. 4405 */ 4406 values[n++] += perf_event_count(leader); 4407 if (read_format & PERF_FORMAT_ID) 4408 values[n++] = primary_event_id(leader); 4409 4410 list_for_each_entry(sub, &leader->sibling_list, group_entry) { 4411 values[n++] += perf_event_count(sub); 4412 if (read_format & PERF_FORMAT_ID) 4413 values[n++] = primary_event_id(sub); 4414 } 4415 4416 return 0; 4417 } 4418 4419 static int perf_read_group(struct perf_event *event, 4420 u64 read_format, char __user *buf) 4421 { 4422 struct perf_event *leader = event->group_leader, *child; 4423 struct perf_event_context *ctx = leader->ctx; 4424 int ret; 4425 u64 *values; 4426 4427 lockdep_assert_held(&ctx->mutex); 4428 4429 values = kzalloc(event->read_size, GFP_KERNEL); 4430 if (!values) 4431 return -ENOMEM; 4432 4433 values[0] = 1 + leader->nr_siblings; 4434 4435 /* 4436 * By locking the child_mutex of the leader we effectively 4437 * lock the child list of all siblings.. XXX explain how. 4438 */ 4439 mutex_lock(&leader->child_mutex); 4440 4441 ret = __perf_read_group_add(leader, read_format, values); 4442 if (ret) 4443 goto unlock; 4444 4445 list_for_each_entry(child, &leader->child_list, child_list) { 4446 ret = __perf_read_group_add(child, read_format, values); 4447 if (ret) 4448 goto unlock; 4449 } 4450 4451 mutex_unlock(&leader->child_mutex); 4452 4453 ret = event->read_size; 4454 if (copy_to_user(buf, values, event->read_size)) 4455 ret = -EFAULT; 4456 goto out; 4457 4458 unlock: 4459 mutex_unlock(&leader->child_mutex); 4460 out: 4461 kfree(values); 4462 return ret; 4463 } 4464 4465 static int perf_read_one(struct perf_event *event, 4466 u64 read_format, char __user *buf) 4467 { 4468 u64 enabled, running; 4469 u64 values[4]; 4470 int n = 0; 4471 4472 values[n++] = perf_event_read_value(event, &enabled, &running); 4473 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 4474 values[n++] = enabled; 4475 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 4476 values[n++] = running; 4477 if (read_format & PERF_FORMAT_ID) 4478 values[n++] = primary_event_id(event); 4479 4480 if (copy_to_user(buf, values, n * sizeof(u64))) 4481 return -EFAULT; 4482 4483 return n * sizeof(u64); 4484 } 4485 4486 static bool is_event_hup(struct perf_event *event) 4487 { 4488 bool no_children; 4489 4490 if (event->state > PERF_EVENT_STATE_EXIT) 4491 return false; 4492 4493 mutex_lock(&event->child_mutex); 4494 no_children = list_empty(&event->child_list); 4495 mutex_unlock(&event->child_mutex); 4496 return no_children; 4497 } 4498 4499 /* 4500 * Read the performance event - simple non blocking version for now 4501 */ 4502 static ssize_t 4503 __perf_read(struct perf_event *event, char __user *buf, size_t count) 4504 { 4505 u64 read_format = event->attr.read_format; 4506 int ret; 4507 4508 /* 4509 * Return end-of-file for a read on a event that is in 4510 * error state (i.e. because it was pinned but it couldn't be 4511 * scheduled on to the CPU at some point). 4512 */ 4513 if (event->state == PERF_EVENT_STATE_ERROR) 4514 return 0; 4515 4516 if (count < event->read_size) 4517 return -ENOSPC; 4518 4519 WARN_ON_ONCE(event->ctx->parent_ctx); 4520 if (read_format & PERF_FORMAT_GROUP) 4521 ret = perf_read_group(event, read_format, buf); 4522 else 4523 ret = perf_read_one(event, read_format, buf); 4524 4525 return ret; 4526 } 4527 4528 static ssize_t 4529 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 4530 { 4531 struct perf_event *event = file->private_data; 4532 struct perf_event_context *ctx; 4533 int ret; 4534 4535 ctx = perf_event_ctx_lock(event); 4536 ret = __perf_read(event, buf, count); 4537 perf_event_ctx_unlock(event, ctx); 4538 4539 return ret; 4540 } 4541 4542 static unsigned int perf_poll(struct file *file, poll_table *wait) 4543 { 4544 struct perf_event *event = file->private_data; 4545 struct ring_buffer *rb; 4546 unsigned int events = POLLHUP; 4547 4548 poll_wait(file, &event->waitq, wait); 4549 4550 if (is_event_hup(event)) 4551 return events; 4552 4553 /* 4554 * Pin the event->rb by taking event->mmap_mutex; otherwise 4555 * perf_event_set_output() can swizzle our rb and make us miss wakeups. 4556 */ 4557 mutex_lock(&event->mmap_mutex); 4558 rb = event->rb; 4559 if (rb) 4560 events = atomic_xchg(&rb->poll, 0); 4561 mutex_unlock(&event->mmap_mutex); 4562 return events; 4563 } 4564 4565 static void _perf_event_reset(struct perf_event *event) 4566 { 4567 (void)perf_event_read(event, false); 4568 local64_set(&event->count, 0); 4569 perf_event_update_userpage(event); 4570 } 4571 4572 /* 4573 * Holding the top-level event's child_mutex means that any 4574 * descendant process that has inherited this event will block 4575 * in perf_event_exit_event() if it goes to exit, thus satisfying the 4576 * task existence requirements of perf_event_enable/disable. 4577 */ 4578 static void perf_event_for_each_child(struct perf_event *event, 4579 void (*func)(struct perf_event *)) 4580 { 4581 struct perf_event *child; 4582 4583 WARN_ON_ONCE(event->ctx->parent_ctx); 4584 4585 mutex_lock(&event->child_mutex); 4586 func(event); 4587 list_for_each_entry(child, &event->child_list, child_list) 4588 func(child); 4589 mutex_unlock(&event->child_mutex); 4590 } 4591 4592 static void perf_event_for_each(struct perf_event *event, 4593 void (*func)(struct perf_event *)) 4594 { 4595 struct perf_event_context *ctx = event->ctx; 4596 struct perf_event *sibling; 4597 4598 lockdep_assert_held(&ctx->mutex); 4599 4600 event = event->group_leader; 4601 4602 perf_event_for_each_child(event, func); 4603 list_for_each_entry(sibling, &event->sibling_list, group_entry) 4604 perf_event_for_each_child(sibling, func); 4605 } 4606 4607 static void __perf_event_period(struct perf_event *event, 4608 struct perf_cpu_context *cpuctx, 4609 struct perf_event_context *ctx, 4610 void *info) 4611 { 4612 u64 value = *((u64 *)info); 4613 bool active; 4614 4615 if (event->attr.freq) { 4616 event->attr.sample_freq = value; 4617 } else { 4618 event->attr.sample_period = value; 4619 event->hw.sample_period = value; 4620 } 4621 4622 active = (event->state == PERF_EVENT_STATE_ACTIVE); 4623 if (active) { 4624 perf_pmu_disable(ctx->pmu); 4625 /* 4626 * We could be throttled; unthrottle now to avoid the tick 4627 * trying to unthrottle while we already re-started the event. 4628 */ 4629 if (event->hw.interrupts == MAX_INTERRUPTS) { 4630 event->hw.interrupts = 0; 4631 perf_log_throttle(event, 1); 4632 } 4633 event->pmu->stop(event, PERF_EF_UPDATE); 4634 } 4635 4636 local64_set(&event->hw.period_left, 0); 4637 4638 if (active) { 4639 event->pmu->start(event, PERF_EF_RELOAD); 4640 perf_pmu_enable(ctx->pmu); 4641 } 4642 } 4643 4644 static int perf_event_period(struct perf_event *event, u64 __user *arg) 4645 { 4646 u64 value; 4647 4648 if (!is_sampling_event(event)) 4649 return -EINVAL; 4650 4651 if (copy_from_user(&value, arg, sizeof(value))) 4652 return -EFAULT; 4653 4654 if (!value) 4655 return -EINVAL; 4656 4657 if (event->attr.freq && value > sysctl_perf_event_sample_rate) 4658 return -EINVAL; 4659 4660 event_function_call(event, __perf_event_period, &value); 4661 4662 return 0; 4663 } 4664 4665 static const struct file_operations perf_fops; 4666 4667 static inline int perf_fget_light(int fd, struct fd *p) 4668 { 4669 struct fd f = fdget(fd); 4670 if (!f.file) 4671 return -EBADF; 4672 4673 if (f.file->f_op != &perf_fops) { 4674 fdput(f); 4675 return -EBADF; 4676 } 4677 *p = f; 4678 return 0; 4679 } 4680 4681 static int perf_event_set_output(struct perf_event *event, 4682 struct perf_event *output_event); 4683 static int perf_event_set_filter(struct perf_event *event, void __user *arg); 4684 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd); 4685 4686 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg) 4687 { 4688 void (*func)(struct perf_event *); 4689 u32 flags = arg; 4690 4691 switch (cmd) { 4692 case PERF_EVENT_IOC_ENABLE: 4693 func = _perf_event_enable; 4694 break; 4695 case PERF_EVENT_IOC_DISABLE: 4696 func = _perf_event_disable; 4697 break; 4698 case PERF_EVENT_IOC_RESET: 4699 func = _perf_event_reset; 4700 break; 4701 4702 case PERF_EVENT_IOC_REFRESH: 4703 return _perf_event_refresh(event, arg); 4704 4705 case PERF_EVENT_IOC_PERIOD: 4706 return perf_event_period(event, (u64 __user *)arg); 4707 4708 case PERF_EVENT_IOC_ID: 4709 { 4710 u64 id = primary_event_id(event); 4711 4712 if (copy_to_user((void __user *)arg, &id, sizeof(id))) 4713 return -EFAULT; 4714 return 0; 4715 } 4716 4717 case PERF_EVENT_IOC_SET_OUTPUT: 4718 { 4719 int ret; 4720 if (arg != -1) { 4721 struct perf_event *output_event; 4722 struct fd output; 4723 ret = perf_fget_light(arg, &output); 4724 if (ret) 4725 return ret; 4726 output_event = output.file->private_data; 4727 ret = perf_event_set_output(event, output_event); 4728 fdput(output); 4729 } else { 4730 ret = perf_event_set_output(event, NULL); 4731 } 4732 return ret; 4733 } 4734 4735 case PERF_EVENT_IOC_SET_FILTER: 4736 return perf_event_set_filter(event, (void __user *)arg); 4737 4738 case PERF_EVENT_IOC_SET_BPF: 4739 return perf_event_set_bpf_prog(event, arg); 4740 4741 case PERF_EVENT_IOC_PAUSE_OUTPUT: { 4742 struct ring_buffer *rb; 4743 4744 rcu_read_lock(); 4745 rb = rcu_dereference(event->rb); 4746 if (!rb || !rb->nr_pages) { 4747 rcu_read_unlock(); 4748 return -EINVAL; 4749 } 4750 rb_toggle_paused(rb, !!arg); 4751 rcu_read_unlock(); 4752 return 0; 4753 } 4754 default: 4755 return -ENOTTY; 4756 } 4757 4758 if (flags & PERF_IOC_FLAG_GROUP) 4759 perf_event_for_each(event, func); 4760 else 4761 perf_event_for_each_child(event, func); 4762 4763 return 0; 4764 } 4765 4766 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 4767 { 4768 struct perf_event *event = file->private_data; 4769 struct perf_event_context *ctx; 4770 long ret; 4771 4772 ctx = perf_event_ctx_lock(event); 4773 ret = _perf_ioctl(event, cmd, arg); 4774 perf_event_ctx_unlock(event, ctx); 4775 4776 return ret; 4777 } 4778 4779 #ifdef CONFIG_COMPAT 4780 static long perf_compat_ioctl(struct file *file, unsigned int cmd, 4781 unsigned long arg) 4782 { 4783 switch (_IOC_NR(cmd)) { 4784 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER): 4785 case _IOC_NR(PERF_EVENT_IOC_ID): 4786 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */ 4787 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) { 4788 cmd &= ~IOCSIZE_MASK; 4789 cmd |= sizeof(void *) << IOCSIZE_SHIFT; 4790 } 4791 break; 4792 } 4793 return perf_ioctl(file, cmd, arg); 4794 } 4795 #else 4796 # define perf_compat_ioctl NULL 4797 #endif 4798 4799 int perf_event_task_enable(void) 4800 { 4801 struct perf_event_context *ctx; 4802 struct perf_event *event; 4803 4804 mutex_lock(¤t->perf_event_mutex); 4805 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { 4806 ctx = perf_event_ctx_lock(event); 4807 perf_event_for_each_child(event, _perf_event_enable); 4808 perf_event_ctx_unlock(event, ctx); 4809 } 4810 mutex_unlock(¤t->perf_event_mutex); 4811 4812 return 0; 4813 } 4814 4815 int perf_event_task_disable(void) 4816 { 4817 struct perf_event_context *ctx; 4818 struct perf_event *event; 4819 4820 mutex_lock(¤t->perf_event_mutex); 4821 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { 4822 ctx = perf_event_ctx_lock(event); 4823 perf_event_for_each_child(event, _perf_event_disable); 4824 perf_event_ctx_unlock(event, ctx); 4825 } 4826 mutex_unlock(¤t->perf_event_mutex); 4827 4828 return 0; 4829 } 4830 4831 static int perf_event_index(struct perf_event *event) 4832 { 4833 if (event->hw.state & PERF_HES_STOPPED) 4834 return 0; 4835 4836 if (event->state != PERF_EVENT_STATE_ACTIVE) 4837 return 0; 4838 4839 return event->pmu->event_idx(event); 4840 } 4841 4842 static void calc_timer_values(struct perf_event *event, 4843 u64 *now, 4844 u64 *enabled, 4845 u64 *running) 4846 { 4847 u64 ctx_time; 4848 4849 *now = perf_clock(); 4850 ctx_time = event->shadow_ctx_time + *now; 4851 *enabled = ctx_time - event->tstamp_enabled; 4852 *running = ctx_time - event->tstamp_running; 4853 } 4854 4855 static void perf_event_init_userpage(struct perf_event *event) 4856 { 4857 struct perf_event_mmap_page *userpg; 4858 struct ring_buffer *rb; 4859 4860 rcu_read_lock(); 4861 rb = rcu_dereference(event->rb); 4862 if (!rb) 4863 goto unlock; 4864 4865 userpg = rb->user_page; 4866 4867 /* Allow new userspace to detect that bit 0 is deprecated */ 4868 userpg->cap_bit0_is_deprecated = 1; 4869 userpg->size = offsetof(struct perf_event_mmap_page, __reserved); 4870 userpg->data_offset = PAGE_SIZE; 4871 userpg->data_size = perf_data_size(rb); 4872 4873 unlock: 4874 rcu_read_unlock(); 4875 } 4876 4877 void __weak arch_perf_update_userpage( 4878 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now) 4879 { 4880 } 4881 4882 /* 4883 * Callers need to ensure there can be no nesting of this function, otherwise 4884 * the seqlock logic goes bad. We can not serialize this because the arch 4885 * code calls this from NMI context. 4886 */ 4887 void perf_event_update_userpage(struct perf_event *event) 4888 { 4889 struct perf_event_mmap_page *userpg; 4890 struct ring_buffer *rb; 4891 u64 enabled, running, now; 4892 4893 rcu_read_lock(); 4894 rb = rcu_dereference(event->rb); 4895 if (!rb) 4896 goto unlock; 4897 4898 /* 4899 * compute total_time_enabled, total_time_running 4900 * based on snapshot values taken when the event 4901 * was last scheduled in. 4902 * 4903 * we cannot simply called update_context_time() 4904 * because of locking issue as we can be called in 4905 * NMI context 4906 */ 4907 calc_timer_values(event, &now, &enabled, &running); 4908 4909 userpg = rb->user_page; 4910 /* 4911 * Disable preemption so as to not let the corresponding user-space 4912 * spin too long if we get preempted. 4913 */ 4914 preempt_disable(); 4915 ++userpg->lock; 4916 barrier(); 4917 userpg->index = perf_event_index(event); 4918 userpg->offset = perf_event_count(event); 4919 if (userpg->index) 4920 userpg->offset -= local64_read(&event->hw.prev_count); 4921 4922 userpg->time_enabled = enabled + 4923 atomic64_read(&event->child_total_time_enabled); 4924 4925 userpg->time_running = running + 4926 atomic64_read(&event->child_total_time_running); 4927 4928 arch_perf_update_userpage(event, userpg, now); 4929 4930 barrier(); 4931 ++userpg->lock; 4932 preempt_enable(); 4933 unlock: 4934 rcu_read_unlock(); 4935 } 4936 4937 static int perf_mmap_fault(struct vm_fault *vmf) 4938 { 4939 struct perf_event *event = vmf->vma->vm_file->private_data; 4940 struct ring_buffer *rb; 4941 int ret = VM_FAULT_SIGBUS; 4942 4943 if (vmf->flags & FAULT_FLAG_MKWRITE) { 4944 if (vmf->pgoff == 0) 4945 ret = 0; 4946 return ret; 4947 } 4948 4949 rcu_read_lock(); 4950 rb = rcu_dereference(event->rb); 4951 if (!rb) 4952 goto unlock; 4953 4954 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE)) 4955 goto unlock; 4956 4957 vmf->page = perf_mmap_to_page(rb, vmf->pgoff); 4958 if (!vmf->page) 4959 goto unlock; 4960 4961 get_page(vmf->page); 4962 vmf->page->mapping = vmf->vma->vm_file->f_mapping; 4963 vmf->page->index = vmf->pgoff; 4964 4965 ret = 0; 4966 unlock: 4967 rcu_read_unlock(); 4968 4969 return ret; 4970 } 4971 4972 static void ring_buffer_attach(struct perf_event *event, 4973 struct ring_buffer *rb) 4974 { 4975 struct ring_buffer *old_rb = NULL; 4976 unsigned long flags; 4977 4978 if (event->rb) { 4979 /* 4980 * Should be impossible, we set this when removing 4981 * event->rb_entry and wait/clear when adding event->rb_entry. 4982 */ 4983 WARN_ON_ONCE(event->rcu_pending); 4984 4985 old_rb = event->rb; 4986 spin_lock_irqsave(&old_rb->event_lock, flags); 4987 list_del_rcu(&event->rb_entry); 4988 spin_unlock_irqrestore(&old_rb->event_lock, flags); 4989 4990 event->rcu_batches = get_state_synchronize_rcu(); 4991 event->rcu_pending = 1; 4992 } 4993 4994 if (rb) { 4995 if (event->rcu_pending) { 4996 cond_synchronize_rcu(event->rcu_batches); 4997 event->rcu_pending = 0; 4998 } 4999 5000 spin_lock_irqsave(&rb->event_lock, flags); 5001 list_add_rcu(&event->rb_entry, &rb->event_list); 5002 spin_unlock_irqrestore(&rb->event_lock, flags); 5003 } 5004 5005 /* 5006 * Avoid racing with perf_mmap_close(AUX): stop the event 5007 * before swizzling the event::rb pointer; if it's getting 5008 * unmapped, its aux_mmap_count will be 0 and it won't 5009 * restart. See the comment in __perf_pmu_output_stop(). 5010 * 5011 * Data will inevitably be lost when set_output is done in 5012 * mid-air, but then again, whoever does it like this is 5013 * not in for the data anyway. 5014 */ 5015 if (has_aux(event)) 5016 perf_event_stop(event, 0); 5017 5018 rcu_assign_pointer(event->rb, rb); 5019 5020 if (old_rb) { 5021 ring_buffer_put(old_rb); 5022 /* 5023 * Since we detached before setting the new rb, so that we 5024 * could attach the new rb, we could have missed a wakeup. 5025 * Provide it now. 5026 */ 5027 wake_up_all(&event->waitq); 5028 } 5029 } 5030 5031 static void ring_buffer_wakeup(struct perf_event *event) 5032 { 5033 struct ring_buffer *rb; 5034 5035 rcu_read_lock(); 5036 rb = rcu_dereference(event->rb); 5037 if (rb) { 5038 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) 5039 wake_up_all(&event->waitq); 5040 } 5041 rcu_read_unlock(); 5042 } 5043 5044 struct ring_buffer *ring_buffer_get(struct perf_event *event) 5045 { 5046 struct ring_buffer *rb; 5047 5048 rcu_read_lock(); 5049 rb = rcu_dereference(event->rb); 5050 if (rb) { 5051 if (!atomic_inc_not_zero(&rb->refcount)) 5052 rb = NULL; 5053 } 5054 rcu_read_unlock(); 5055 5056 return rb; 5057 } 5058 5059 void ring_buffer_put(struct ring_buffer *rb) 5060 { 5061 if (!atomic_dec_and_test(&rb->refcount)) 5062 return; 5063 5064 WARN_ON_ONCE(!list_empty(&rb->event_list)); 5065 5066 call_rcu(&rb->rcu_head, rb_free_rcu); 5067 } 5068 5069 static void perf_mmap_open(struct vm_area_struct *vma) 5070 { 5071 struct perf_event *event = vma->vm_file->private_data; 5072 5073 atomic_inc(&event->mmap_count); 5074 atomic_inc(&event->rb->mmap_count); 5075 5076 if (vma->vm_pgoff) 5077 atomic_inc(&event->rb->aux_mmap_count); 5078 5079 if (event->pmu->event_mapped) 5080 event->pmu->event_mapped(event); 5081 } 5082 5083 static void perf_pmu_output_stop(struct perf_event *event); 5084 5085 /* 5086 * A buffer can be mmap()ed multiple times; either directly through the same 5087 * event, or through other events by use of perf_event_set_output(). 5088 * 5089 * In order to undo the VM accounting done by perf_mmap() we need to destroy 5090 * the buffer here, where we still have a VM context. This means we need 5091 * to detach all events redirecting to us. 5092 */ 5093 static void perf_mmap_close(struct vm_area_struct *vma) 5094 { 5095 struct perf_event *event = vma->vm_file->private_data; 5096 5097 struct ring_buffer *rb = ring_buffer_get(event); 5098 struct user_struct *mmap_user = rb->mmap_user; 5099 int mmap_locked = rb->mmap_locked; 5100 unsigned long size = perf_data_size(rb); 5101 5102 if (event->pmu->event_unmapped) 5103 event->pmu->event_unmapped(event); 5104 5105 /* 5106 * rb->aux_mmap_count will always drop before rb->mmap_count and 5107 * event->mmap_count, so it is ok to use event->mmap_mutex to 5108 * serialize with perf_mmap here. 5109 */ 5110 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff && 5111 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) { 5112 /* 5113 * Stop all AUX events that are writing to this buffer, 5114 * so that we can free its AUX pages and corresponding PMU 5115 * data. Note that after rb::aux_mmap_count dropped to zero, 5116 * they won't start any more (see perf_aux_output_begin()). 5117 */ 5118 perf_pmu_output_stop(event); 5119 5120 /* now it's safe to free the pages */ 5121 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm); 5122 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked; 5123 5124 /* this has to be the last one */ 5125 rb_free_aux(rb); 5126 WARN_ON_ONCE(atomic_read(&rb->aux_refcount)); 5127 5128 mutex_unlock(&event->mmap_mutex); 5129 } 5130 5131 atomic_dec(&rb->mmap_count); 5132 5133 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) 5134 goto out_put; 5135 5136 ring_buffer_attach(event, NULL); 5137 mutex_unlock(&event->mmap_mutex); 5138 5139 /* If there's still other mmap()s of this buffer, we're done. */ 5140 if (atomic_read(&rb->mmap_count)) 5141 goto out_put; 5142 5143 /* 5144 * No other mmap()s, detach from all other events that might redirect 5145 * into the now unreachable buffer. Somewhat complicated by the 5146 * fact that rb::event_lock otherwise nests inside mmap_mutex. 5147 */ 5148 again: 5149 rcu_read_lock(); 5150 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) { 5151 if (!atomic_long_inc_not_zero(&event->refcount)) { 5152 /* 5153 * This event is en-route to free_event() which will 5154 * detach it and remove it from the list. 5155 */ 5156 continue; 5157 } 5158 rcu_read_unlock(); 5159 5160 mutex_lock(&event->mmap_mutex); 5161 /* 5162 * Check we didn't race with perf_event_set_output() which can 5163 * swizzle the rb from under us while we were waiting to 5164 * acquire mmap_mutex. 5165 * 5166 * If we find a different rb; ignore this event, a next 5167 * iteration will no longer find it on the list. We have to 5168 * still restart the iteration to make sure we're not now 5169 * iterating the wrong list. 5170 */ 5171 if (event->rb == rb) 5172 ring_buffer_attach(event, NULL); 5173 5174 mutex_unlock(&event->mmap_mutex); 5175 put_event(event); 5176 5177 /* 5178 * Restart the iteration; either we're on the wrong list or 5179 * destroyed its integrity by doing a deletion. 5180 */ 5181 goto again; 5182 } 5183 rcu_read_unlock(); 5184 5185 /* 5186 * It could be there's still a few 0-ref events on the list; they'll 5187 * get cleaned up by free_event() -- they'll also still have their 5188 * ref on the rb and will free it whenever they are done with it. 5189 * 5190 * Aside from that, this buffer is 'fully' detached and unmapped, 5191 * undo the VM accounting. 5192 */ 5193 5194 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm); 5195 vma->vm_mm->pinned_vm -= mmap_locked; 5196 free_uid(mmap_user); 5197 5198 out_put: 5199 ring_buffer_put(rb); /* could be last */ 5200 } 5201 5202 static const struct vm_operations_struct perf_mmap_vmops = { 5203 .open = perf_mmap_open, 5204 .close = perf_mmap_close, /* non mergable */ 5205 .fault = perf_mmap_fault, 5206 .page_mkwrite = perf_mmap_fault, 5207 }; 5208 5209 static int perf_mmap(struct file *file, struct vm_area_struct *vma) 5210 { 5211 struct perf_event *event = file->private_data; 5212 unsigned long user_locked, user_lock_limit; 5213 struct user_struct *user = current_user(); 5214 unsigned long locked, lock_limit; 5215 struct ring_buffer *rb = NULL; 5216 unsigned long vma_size; 5217 unsigned long nr_pages; 5218 long user_extra = 0, extra = 0; 5219 int ret = 0, flags = 0; 5220 5221 /* 5222 * Don't allow mmap() of inherited per-task counters. This would 5223 * create a performance issue due to all children writing to the 5224 * same rb. 5225 */ 5226 if (event->cpu == -1 && event->attr.inherit) 5227 return -EINVAL; 5228 5229 if (!(vma->vm_flags & VM_SHARED)) 5230 return -EINVAL; 5231 5232 vma_size = vma->vm_end - vma->vm_start; 5233 5234 if (vma->vm_pgoff == 0) { 5235 nr_pages = (vma_size / PAGE_SIZE) - 1; 5236 } else { 5237 /* 5238 * AUX area mapping: if rb->aux_nr_pages != 0, it's already 5239 * mapped, all subsequent mappings should have the same size 5240 * and offset. Must be above the normal perf buffer. 5241 */ 5242 u64 aux_offset, aux_size; 5243 5244 if (!event->rb) 5245 return -EINVAL; 5246 5247 nr_pages = vma_size / PAGE_SIZE; 5248 5249 mutex_lock(&event->mmap_mutex); 5250 ret = -EINVAL; 5251 5252 rb = event->rb; 5253 if (!rb) 5254 goto aux_unlock; 5255 5256 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset); 5257 aux_size = ACCESS_ONCE(rb->user_page->aux_size); 5258 5259 if (aux_offset < perf_data_size(rb) + PAGE_SIZE) 5260 goto aux_unlock; 5261 5262 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT) 5263 goto aux_unlock; 5264 5265 /* already mapped with a different offset */ 5266 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff) 5267 goto aux_unlock; 5268 5269 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE) 5270 goto aux_unlock; 5271 5272 /* already mapped with a different size */ 5273 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages) 5274 goto aux_unlock; 5275 5276 if (!is_power_of_2(nr_pages)) 5277 goto aux_unlock; 5278 5279 if (!atomic_inc_not_zero(&rb->mmap_count)) 5280 goto aux_unlock; 5281 5282 if (rb_has_aux(rb)) { 5283 atomic_inc(&rb->aux_mmap_count); 5284 ret = 0; 5285 goto unlock; 5286 } 5287 5288 atomic_set(&rb->aux_mmap_count, 1); 5289 user_extra = nr_pages; 5290 5291 goto accounting; 5292 } 5293 5294 /* 5295 * If we have rb pages ensure they're a power-of-two number, so we 5296 * can do bitmasks instead of modulo. 5297 */ 5298 if (nr_pages != 0 && !is_power_of_2(nr_pages)) 5299 return -EINVAL; 5300 5301 if (vma_size != PAGE_SIZE * (1 + nr_pages)) 5302 return -EINVAL; 5303 5304 WARN_ON_ONCE(event->ctx->parent_ctx); 5305 again: 5306 mutex_lock(&event->mmap_mutex); 5307 if (event->rb) { 5308 if (event->rb->nr_pages != nr_pages) { 5309 ret = -EINVAL; 5310 goto unlock; 5311 } 5312 5313 if (!atomic_inc_not_zero(&event->rb->mmap_count)) { 5314 /* 5315 * Raced against perf_mmap_close() through 5316 * perf_event_set_output(). Try again, hope for better 5317 * luck. 5318 */ 5319 mutex_unlock(&event->mmap_mutex); 5320 goto again; 5321 } 5322 5323 goto unlock; 5324 } 5325 5326 user_extra = nr_pages + 1; 5327 5328 accounting: 5329 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10); 5330 5331 /* 5332 * Increase the limit linearly with more CPUs: 5333 */ 5334 user_lock_limit *= num_online_cpus(); 5335 5336 user_locked = atomic_long_read(&user->locked_vm) + user_extra; 5337 5338 if (user_locked > user_lock_limit) 5339 extra = user_locked - user_lock_limit; 5340 5341 lock_limit = rlimit(RLIMIT_MEMLOCK); 5342 lock_limit >>= PAGE_SHIFT; 5343 locked = vma->vm_mm->pinned_vm + extra; 5344 5345 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() && 5346 !capable(CAP_IPC_LOCK)) { 5347 ret = -EPERM; 5348 goto unlock; 5349 } 5350 5351 WARN_ON(!rb && event->rb); 5352 5353 if (vma->vm_flags & VM_WRITE) 5354 flags |= RING_BUFFER_WRITABLE; 5355 5356 if (!rb) { 5357 rb = rb_alloc(nr_pages, 5358 event->attr.watermark ? event->attr.wakeup_watermark : 0, 5359 event->cpu, flags); 5360 5361 if (!rb) { 5362 ret = -ENOMEM; 5363 goto unlock; 5364 } 5365 5366 atomic_set(&rb->mmap_count, 1); 5367 rb->mmap_user = get_current_user(); 5368 rb->mmap_locked = extra; 5369 5370 ring_buffer_attach(event, rb); 5371 5372 perf_event_init_userpage(event); 5373 perf_event_update_userpage(event); 5374 } else { 5375 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages, 5376 event->attr.aux_watermark, flags); 5377 if (!ret) 5378 rb->aux_mmap_locked = extra; 5379 } 5380 5381 unlock: 5382 if (!ret) { 5383 atomic_long_add(user_extra, &user->locked_vm); 5384 vma->vm_mm->pinned_vm += extra; 5385 5386 atomic_inc(&event->mmap_count); 5387 } else if (rb) { 5388 atomic_dec(&rb->mmap_count); 5389 } 5390 aux_unlock: 5391 mutex_unlock(&event->mmap_mutex); 5392 5393 /* 5394 * Since pinned accounting is per vm we cannot allow fork() to copy our 5395 * vma. 5396 */ 5397 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP; 5398 vma->vm_ops = &perf_mmap_vmops; 5399 5400 if (event->pmu->event_mapped) 5401 event->pmu->event_mapped(event); 5402 5403 return ret; 5404 } 5405 5406 static int perf_fasync(int fd, struct file *filp, int on) 5407 { 5408 struct inode *inode = file_inode(filp); 5409 struct perf_event *event = filp->private_data; 5410 int retval; 5411 5412 inode_lock(inode); 5413 retval = fasync_helper(fd, filp, on, &event->fasync); 5414 inode_unlock(inode); 5415 5416 if (retval < 0) 5417 return retval; 5418 5419 return 0; 5420 } 5421 5422 static const struct file_operations perf_fops = { 5423 .llseek = no_llseek, 5424 .release = perf_release, 5425 .read = perf_read, 5426 .poll = perf_poll, 5427 .unlocked_ioctl = perf_ioctl, 5428 .compat_ioctl = perf_compat_ioctl, 5429 .mmap = perf_mmap, 5430 .fasync = perf_fasync, 5431 }; 5432 5433 /* 5434 * Perf event wakeup 5435 * 5436 * If there's data, ensure we set the poll() state and publish everything 5437 * to user-space before waking everybody up. 5438 */ 5439 5440 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event) 5441 { 5442 /* only the parent has fasync state */ 5443 if (event->parent) 5444 event = event->parent; 5445 return &event->fasync; 5446 } 5447 5448 void perf_event_wakeup(struct perf_event *event) 5449 { 5450 ring_buffer_wakeup(event); 5451 5452 if (event->pending_kill) { 5453 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill); 5454 event->pending_kill = 0; 5455 } 5456 } 5457 5458 static void perf_pending_event(struct irq_work *entry) 5459 { 5460 struct perf_event *event = container_of(entry, 5461 struct perf_event, pending); 5462 int rctx; 5463 5464 rctx = perf_swevent_get_recursion_context(); 5465 /* 5466 * If we 'fail' here, that's OK, it means recursion is already disabled 5467 * and we won't recurse 'further'. 5468 */ 5469 5470 if (event->pending_disable) { 5471 event->pending_disable = 0; 5472 perf_event_disable_local(event); 5473 } 5474 5475 if (event->pending_wakeup) { 5476 event->pending_wakeup = 0; 5477 perf_event_wakeup(event); 5478 } 5479 5480 if (rctx >= 0) 5481 perf_swevent_put_recursion_context(rctx); 5482 } 5483 5484 /* 5485 * We assume there is only KVM supporting the callbacks. 5486 * Later on, we might change it to a list if there is 5487 * another virtualization implementation supporting the callbacks. 5488 */ 5489 struct perf_guest_info_callbacks *perf_guest_cbs; 5490 5491 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) 5492 { 5493 perf_guest_cbs = cbs; 5494 return 0; 5495 } 5496 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks); 5497 5498 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) 5499 { 5500 perf_guest_cbs = NULL; 5501 return 0; 5502 } 5503 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks); 5504 5505 static void 5506 perf_output_sample_regs(struct perf_output_handle *handle, 5507 struct pt_regs *regs, u64 mask) 5508 { 5509 int bit; 5510 DECLARE_BITMAP(_mask, 64); 5511 5512 bitmap_from_u64(_mask, mask); 5513 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) { 5514 u64 val; 5515 5516 val = perf_reg_value(regs, bit); 5517 perf_output_put(handle, val); 5518 } 5519 } 5520 5521 static void perf_sample_regs_user(struct perf_regs *regs_user, 5522 struct pt_regs *regs, 5523 struct pt_regs *regs_user_copy) 5524 { 5525 if (user_mode(regs)) { 5526 regs_user->abi = perf_reg_abi(current); 5527 regs_user->regs = regs; 5528 } else if (current->mm) { 5529 perf_get_regs_user(regs_user, regs, regs_user_copy); 5530 } else { 5531 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE; 5532 regs_user->regs = NULL; 5533 } 5534 } 5535 5536 static void perf_sample_regs_intr(struct perf_regs *regs_intr, 5537 struct pt_regs *regs) 5538 { 5539 regs_intr->regs = regs; 5540 regs_intr->abi = perf_reg_abi(current); 5541 } 5542 5543 5544 /* 5545 * Get remaining task size from user stack pointer. 5546 * 5547 * It'd be better to take stack vma map and limit this more 5548 * precisly, but there's no way to get it safely under interrupt, 5549 * so using TASK_SIZE as limit. 5550 */ 5551 static u64 perf_ustack_task_size(struct pt_regs *regs) 5552 { 5553 unsigned long addr = perf_user_stack_pointer(regs); 5554 5555 if (!addr || addr >= TASK_SIZE) 5556 return 0; 5557 5558 return TASK_SIZE - addr; 5559 } 5560 5561 static u16 5562 perf_sample_ustack_size(u16 stack_size, u16 header_size, 5563 struct pt_regs *regs) 5564 { 5565 u64 task_size; 5566 5567 /* No regs, no stack pointer, no dump. */ 5568 if (!regs) 5569 return 0; 5570 5571 /* 5572 * Check if we fit in with the requested stack size into the: 5573 * - TASK_SIZE 5574 * If we don't, we limit the size to the TASK_SIZE. 5575 * 5576 * - remaining sample size 5577 * If we don't, we customize the stack size to 5578 * fit in to the remaining sample size. 5579 */ 5580 5581 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs)); 5582 stack_size = min(stack_size, (u16) task_size); 5583 5584 /* Current header size plus static size and dynamic size. */ 5585 header_size += 2 * sizeof(u64); 5586 5587 /* Do we fit in with the current stack dump size? */ 5588 if ((u16) (header_size + stack_size) < header_size) { 5589 /* 5590 * If we overflow the maximum size for the sample, 5591 * we customize the stack dump size to fit in. 5592 */ 5593 stack_size = USHRT_MAX - header_size - sizeof(u64); 5594 stack_size = round_up(stack_size, sizeof(u64)); 5595 } 5596 5597 return stack_size; 5598 } 5599 5600 static void 5601 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size, 5602 struct pt_regs *regs) 5603 { 5604 /* Case of a kernel thread, nothing to dump */ 5605 if (!regs) { 5606 u64 size = 0; 5607 perf_output_put(handle, size); 5608 } else { 5609 unsigned long sp; 5610 unsigned int rem; 5611 u64 dyn_size; 5612 5613 /* 5614 * We dump: 5615 * static size 5616 * - the size requested by user or the best one we can fit 5617 * in to the sample max size 5618 * data 5619 * - user stack dump data 5620 * dynamic size 5621 * - the actual dumped size 5622 */ 5623 5624 /* Static size. */ 5625 perf_output_put(handle, dump_size); 5626 5627 /* Data. */ 5628 sp = perf_user_stack_pointer(regs); 5629 rem = __output_copy_user(handle, (void *) sp, dump_size); 5630 dyn_size = dump_size - rem; 5631 5632 perf_output_skip(handle, rem); 5633 5634 /* Dynamic size. */ 5635 perf_output_put(handle, dyn_size); 5636 } 5637 } 5638 5639 static void __perf_event_header__init_id(struct perf_event_header *header, 5640 struct perf_sample_data *data, 5641 struct perf_event *event) 5642 { 5643 u64 sample_type = event->attr.sample_type; 5644 5645 data->type = sample_type; 5646 header->size += event->id_header_size; 5647 5648 if (sample_type & PERF_SAMPLE_TID) { 5649 /* namespace issues */ 5650 data->tid_entry.pid = perf_event_pid(event, current); 5651 data->tid_entry.tid = perf_event_tid(event, current); 5652 } 5653 5654 if (sample_type & PERF_SAMPLE_TIME) 5655 data->time = perf_event_clock(event); 5656 5657 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER)) 5658 data->id = primary_event_id(event); 5659 5660 if (sample_type & PERF_SAMPLE_STREAM_ID) 5661 data->stream_id = event->id; 5662 5663 if (sample_type & PERF_SAMPLE_CPU) { 5664 data->cpu_entry.cpu = raw_smp_processor_id(); 5665 data->cpu_entry.reserved = 0; 5666 } 5667 } 5668 5669 void perf_event_header__init_id(struct perf_event_header *header, 5670 struct perf_sample_data *data, 5671 struct perf_event *event) 5672 { 5673 if (event->attr.sample_id_all) 5674 __perf_event_header__init_id(header, data, event); 5675 } 5676 5677 static void __perf_event__output_id_sample(struct perf_output_handle *handle, 5678 struct perf_sample_data *data) 5679 { 5680 u64 sample_type = data->type; 5681 5682 if (sample_type & PERF_SAMPLE_TID) 5683 perf_output_put(handle, data->tid_entry); 5684 5685 if (sample_type & PERF_SAMPLE_TIME) 5686 perf_output_put(handle, data->time); 5687 5688 if (sample_type & PERF_SAMPLE_ID) 5689 perf_output_put(handle, data->id); 5690 5691 if (sample_type & PERF_SAMPLE_STREAM_ID) 5692 perf_output_put(handle, data->stream_id); 5693 5694 if (sample_type & PERF_SAMPLE_CPU) 5695 perf_output_put(handle, data->cpu_entry); 5696 5697 if (sample_type & PERF_SAMPLE_IDENTIFIER) 5698 perf_output_put(handle, data->id); 5699 } 5700 5701 void perf_event__output_id_sample(struct perf_event *event, 5702 struct perf_output_handle *handle, 5703 struct perf_sample_data *sample) 5704 { 5705 if (event->attr.sample_id_all) 5706 __perf_event__output_id_sample(handle, sample); 5707 } 5708 5709 static void perf_output_read_one(struct perf_output_handle *handle, 5710 struct perf_event *event, 5711 u64 enabled, u64 running) 5712 { 5713 u64 read_format = event->attr.read_format; 5714 u64 values[4]; 5715 int n = 0; 5716 5717 values[n++] = perf_event_count(event); 5718 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { 5719 values[n++] = enabled + 5720 atomic64_read(&event->child_total_time_enabled); 5721 } 5722 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { 5723 values[n++] = running + 5724 atomic64_read(&event->child_total_time_running); 5725 } 5726 if (read_format & PERF_FORMAT_ID) 5727 values[n++] = primary_event_id(event); 5728 5729 __output_copy(handle, values, n * sizeof(u64)); 5730 } 5731 5732 /* 5733 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult. 5734 */ 5735 static void perf_output_read_group(struct perf_output_handle *handle, 5736 struct perf_event *event, 5737 u64 enabled, u64 running) 5738 { 5739 struct perf_event *leader = event->group_leader, *sub; 5740 u64 read_format = event->attr.read_format; 5741 u64 values[5]; 5742 int n = 0; 5743 5744 values[n++] = 1 + leader->nr_siblings; 5745 5746 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 5747 values[n++] = enabled; 5748 5749 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 5750 values[n++] = running; 5751 5752 if (leader != event) 5753 leader->pmu->read(leader); 5754 5755 values[n++] = perf_event_count(leader); 5756 if (read_format & PERF_FORMAT_ID) 5757 values[n++] = primary_event_id(leader); 5758 5759 __output_copy(handle, values, n * sizeof(u64)); 5760 5761 list_for_each_entry(sub, &leader->sibling_list, group_entry) { 5762 n = 0; 5763 5764 if ((sub != event) && 5765 (sub->state == PERF_EVENT_STATE_ACTIVE)) 5766 sub->pmu->read(sub); 5767 5768 values[n++] = perf_event_count(sub); 5769 if (read_format & PERF_FORMAT_ID) 5770 values[n++] = primary_event_id(sub); 5771 5772 __output_copy(handle, values, n * sizeof(u64)); 5773 } 5774 } 5775 5776 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\ 5777 PERF_FORMAT_TOTAL_TIME_RUNNING) 5778 5779 static void perf_output_read(struct perf_output_handle *handle, 5780 struct perf_event *event) 5781 { 5782 u64 enabled = 0, running = 0, now; 5783 u64 read_format = event->attr.read_format; 5784 5785 /* 5786 * compute total_time_enabled, total_time_running 5787 * based on snapshot values taken when the event 5788 * was last scheduled in. 5789 * 5790 * we cannot simply called update_context_time() 5791 * because of locking issue as we are called in 5792 * NMI context 5793 */ 5794 if (read_format & PERF_FORMAT_TOTAL_TIMES) 5795 calc_timer_values(event, &now, &enabled, &running); 5796 5797 if (event->attr.read_format & PERF_FORMAT_GROUP) 5798 perf_output_read_group(handle, event, enabled, running); 5799 else 5800 perf_output_read_one(handle, event, enabled, running); 5801 } 5802 5803 void perf_output_sample(struct perf_output_handle *handle, 5804 struct perf_event_header *header, 5805 struct perf_sample_data *data, 5806 struct perf_event *event) 5807 { 5808 u64 sample_type = data->type; 5809 5810 perf_output_put(handle, *header); 5811 5812 if (sample_type & PERF_SAMPLE_IDENTIFIER) 5813 perf_output_put(handle, data->id); 5814 5815 if (sample_type & PERF_SAMPLE_IP) 5816 perf_output_put(handle, data->ip); 5817 5818 if (sample_type & PERF_SAMPLE_TID) 5819 perf_output_put(handle, data->tid_entry); 5820 5821 if (sample_type & PERF_SAMPLE_TIME) 5822 perf_output_put(handle, data->time); 5823 5824 if (sample_type & PERF_SAMPLE_ADDR) 5825 perf_output_put(handle, data->addr); 5826 5827 if (sample_type & PERF_SAMPLE_ID) 5828 perf_output_put(handle, data->id); 5829 5830 if (sample_type & PERF_SAMPLE_STREAM_ID) 5831 perf_output_put(handle, data->stream_id); 5832 5833 if (sample_type & PERF_SAMPLE_CPU) 5834 perf_output_put(handle, data->cpu_entry); 5835 5836 if (sample_type & PERF_SAMPLE_PERIOD) 5837 perf_output_put(handle, data->period); 5838 5839 if (sample_type & PERF_SAMPLE_READ) 5840 perf_output_read(handle, event); 5841 5842 if (sample_type & PERF_SAMPLE_CALLCHAIN) { 5843 if (data->callchain) { 5844 int size = 1; 5845 5846 if (data->callchain) 5847 size += data->callchain->nr; 5848 5849 size *= sizeof(u64); 5850 5851 __output_copy(handle, data->callchain, size); 5852 } else { 5853 u64 nr = 0; 5854 perf_output_put(handle, nr); 5855 } 5856 } 5857 5858 if (sample_type & PERF_SAMPLE_RAW) { 5859 struct perf_raw_record *raw = data->raw; 5860 5861 if (raw) { 5862 struct perf_raw_frag *frag = &raw->frag; 5863 5864 perf_output_put(handle, raw->size); 5865 do { 5866 if (frag->copy) { 5867 __output_custom(handle, frag->copy, 5868 frag->data, frag->size); 5869 } else { 5870 __output_copy(handle, frag->data, 5871 frag->size); 5872 } 5873 if (perf_raw_frag_last(frag)) 5874 break; 5875 frag = frag->next; 5876 } while (1); 5877 if (frag->pad) 5878 __output_skip(handle, NULL, frag->pad); 5879 } else { 5880 struct { 5881 u32 size; 5882 u32 data; 5883 } raw = { 5884 .size = sizeof(u32), 5885 .data = 0, 5886 }; 5887 perf_output_put(handle, raw); 5888 } 5889 } 5890 5891 if (sample_type & PERF_SAMPLE_BRANCH_STACK) { 5892 if (data->br_stack) { 5893 size_t size; 5894 5895 size = data->br_stack->nr 5896 * sizeof(struct perf_branch_entry); 5897 5898 perf_output_put(handle, data->br_stack->nr); 5899 perf_output_copy(handle, data->br_stack->entries, size); 5900 } else { 5901 /* 5902 * we always store at least the value of nr 5903 */ 5904 u64 nr = 0; 5905 perf_output_put(handle, nr); 5906 } 5907 } 5908 5909 if (sample_type & PERF_SAMPLE_REGS_USER) { 5910 u64 abi = data->regs_user.abi; 5911 5912 /* 5913 * If there are no regs to dump, notice it through 5914 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). 5915 */ 5916 perf_output_put(handle, abi); 5917 5918 if (abi) { 5919 u64 mask = event->attr.sample_regs_user; 5920 perf_output_sample_regs(handle, 5921 data->regs_user.regs, 5922 mask); 5923 } 5924 } 5925 5926 if (sample_type & PERF_SAMPLE_STACK_USER) { 5927 perf_output_sample_ustack(handle, 5928 data->stack_user_size, 5929 data->regs_user.regs); 5930 } 5931 5932 if (sample_type & PERF_SAMPLE_WEIGHT) 5933 perf_output_put(handle, data->weight); 5934 5935 if (sample_type & PERF_SAMPLE_DATA_SRC) 5936 perf_output_put(handle, data->data_src.val); 5937 5938 if (sample_type & PERF_SAMPLE_TRANSACTION) 5939 perf_output_put(handle, data->txn); 5940 5941 if (sample_type & PERF_SAMPLE_REGS_INTR) { 5942 u64 abi = data->regs_intr.abi; 5943 /* 5944 * If there are no regs to dump, notice it through 5945 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). 5946 */ 5947 perf_output_put(handle, abi); 5948 5949 if (abi) { 5950 u64 mask = event->attr.sample_regs_intr; 5951 5952 perf_output_sample_regs(handle, 5953 data->regs_intr.regs, 5954 mask); 5955 } 5956 } 5957 5958 if (!event->attr.watermark) { 5959 int wakeup_events = event->attr.wakeup_events; 5960 5961 if (wakeup_events) { 5962 struct ring_buffer *rb = handle->rb; 5963 int events = local_inc_return(&rb->events); 5964 5965 if (events >= wakeup_events) { 5966 local_sub(wakeup_events, &rb->events); 5967 local_inc(&rb->wakeup); 5968 } 5969 } 5970 } 5971 } 5972 5973 void perf_prepare_sample(struct perf_event_header *header, 5974 struct perf_sample_data *data, 5975 struct perf_event *event, 5976 struct pt_regs *regs) 5977 { 5978 u64 sample_type = event->attr.sample_type; 5979 5980 header->type = PERF_RECORD_SAMPLE; 5981 header->size = sizeof(*header) + event->header_size; 5982 5983 header->misc = 0; 5984 header->misc |= perf_misc_flags(regs); 5985 5986 __perf_event_header__init_id(header, data, event); 5987 5988 if (sample_type & PERF_SAMPLE_IP) 5989 data->ip = perf_instruction_pointer(regs); 5990 5991 if (sample_type & PERF_SAMPLE_CALLCHAIN) { 5992 int size = 1; 5993 5994 data->callchain = perf_callchain(event, regs); 5995 5996 if (data->callchain) 5997 size += data->callchain->nr; 5998 5999 header->size += size * sizeof(u64); 6000 } 6001 6002 if (sample_type & PERF_SAMPLE_RAW) { 6003 struct perf_raw_record *raw = data->raw; 6004 int size; 6005 6006 if (raw) { 6007 struct perf_raw_frag *frag = &raw->frag; 6008 u32 sum = 0; 6009 6010 do { 6011 sum += frag->size; 6012 if (perf_raw_frag_last(frag)) 6013 break; 6014 frag = frag->next; 6015 } while (1); 6016 6017 size = round_up(sum + sizeof(u32), sizeof(u64)); 6018 raw->size = size - sizeof(u32); 6019 frag->pad = raw->size - sum; 6020 } else { 6021 size = sizeof(u64); 6022 } 6023 6024 header->size += size; 6025 } 6026 6027 if (sample_type & PERF_SAMPLE_BRANCH_STACK) { 6028 int size = sizeof(u64); /* nr */ 6029 if (data->br_stack) { 6030 size += data->br_stack->nr 6031 * sizeof(struct perf_branch_entry); 6032 } 6033 header->size += size; 6034 } 6035 6036 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER)) 6037 perf_sample_regs_user(&data->regs_user, regs, 6038 &data->regs_user_copy); 6039 6040 if (sample_type & PERF_SAMPLE_REGS_USER) { 6041 /* regs dump ABI info */ 6042 int size = sizeof(u64); 6043 6044 if (data->regs_user.regs) { 6045 u64 mask = event->attr.sample_regs_user; 6046 size += hweight64(mask) * sizeof(u64); 6047 } 6048 6049 header->size += size; 6050 } 6051 6052 if (sample_type & PERF_SAMPLE_STACK_USER) { 6053 /* 6054 * Either we need PERF_SAMPLE_STACK_USER bit to be allways 6055 * processed as the last one or have additional check added 6056 * in case new sample type is added, because we could eat 6057 * up the rest of the sample size. 6058 */ 6059 u16 stack_size = event->attr.sample_stack_user; 6060 u16 size = sizeof(u64); 6061 6062 stack_size = perf_sample_ustack_size(stack_size, header->size, 6063 data->regs_user.regs); 6064 6065 /* 6066 * If there is something to dump, add space for the dump 6067 * itself and for the field that tells the dynamic size, 6068 * which is how many have been actually dumped. 6069 */ 6070 if (stack_size) 6071 size += sizeof(u64) + stack_size; 6072 6073 data->stack_user_size = stack_size; 6074 header->size += size; 6075 } 6076 6077 if (sample_type & PERF_SAMPLE_REGS_INTR) { 6078 /* regs dump ABI info */ 6079 int size = sizeof(u64); 6080 6081 perf_sample_regs_intr(&data->regs_intr, regs); 6082 6083 if (data->regs_intr.regs) { 6084 u64 mask = event->attr.sample_regs_intr; 6085 6086 size += hweight64(mask) * sizeof(u64); 6087 } 6088 6089 header->size += size; 6090 } 6091 } 6092 6093 static void __always_inline 6094 __perf_event_output(struct perf_event *event, 6095 struct perf_sample_data *data, 6096 struct pt_regs *regs, 6097 int (*output_begin)(struct perf_output_handle *, 6098 struct perf_event *, 6099 unsigned int)) 6100 { 6101 struct perf_output_handle handle; 6102 struct perf_event_header header; 6103 6104 /* protect the callchain buffers */ 6105 rcu_read_lock(); 6106 6107 perf_prepare_sample(&header, data, event, regs); 6108 6109 if (output_begin(&handle, event, header.size)) 6110 goto exit; 6111 6112 perf_output_sample(&handle, &header, data, event); 6113 6114 perf_output_end(&handle); 6115 6116 exit: 6117 rcu_read_unlock(); 6118 } 6119 6120 void 6121 perf_event_output_forward(struct perf_event *event, 6122 struct perf_sample_data *data, 6123 struct pt_regs *regs) 6124 { 6125 __perf_event_output(event, data, regs, perf_output_begin_forward); 6126 } 6127 6128 void 6129 perf_event_output_backward(struct perf_event *event, 6130 struct perf_sample_data *data, 6131 struct pt_regs *regs) 6132 { 6133 __perf_event_output(event, data, regs, perf_output_begin_backward); 6134 } 6135 6136 void 6137 perf_event_output(struct perf_event *event, 6138 struct perf_sample_data *data, 6139 struct pt_regs *regs) 6140 { 6141 __perf_event_output(event, data, regs, perf_output_begin); 6142 } 6143 6144 /* 6145 * read event_id 6146 */ 6147 6148 struct perf_read_event { 6149 struct perf_event_header header; 6150 6151 u32 pid; 6152 u32 tid; 6153 }; 6154 6155 static void 6156 perf_event_read_event(struct perf_event *event, 6157 struct task_struct *task) 6158 { 6159 struct perf_output_handle handle; 6160 struct perf_sample_data sample; 6161 struct perf_read_event read_event = { 6162 .header = { 6163 .type = PERF_RECORD_READ, 6164 .misc = 0, 6165 .size = sizeof(read_event) + event->read_size, 6166 }, 6167 .pid = perf_event_pid(event, task), 6168 .tid = perf_event_tid(event, task), 6169 }; 6170 int ret; 6171 6172 perf_event_header__init_id(&read_event.header, &sample, event); 6173 ret = perf_output_begin(&handle, event, read_event.header.size); 6174 if (ret) 6175 return; 6176 6177 perf_output_put(&handle, read_event); 6178 perf_output_read(&handle, event); 6179 perf_event__output_id_sample(event, &handle, &sample); 6180 6181 perf_output_end(&handle); 6182 } 6183 6184 typedef void (perf_iterate_f)(struct perf_event *event, void *data); 6185 6186 static void 6187 perf_iterate_ctx(struct perf_event_context *ctx, 6188 perf_iterate_f output, 6189 void *data, bool all) 6190 { 6191 struct perf_event *event; 6192 6193 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 6194 if (!all) { 6195 if (event->state < PERF_EVENT_STATE_INACTIVE) 6196 continue; 6197 if (!event_filter_match(event)) 6198 continue; 6199 } 6200 6201 output(event, data); 6202 } 6203 } 6204 6205 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data) 6206 { 6207 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events); 6208 struct perf_event *event; 6209 6210 list_for_each_entry_rcu(event, &pel->list, sb_list) { 6211 /* 6212 * Skip events that are not fully formed yet; ensure that 6213 * if we observe event->ctx, both event and ctx will be 6214 * complete enough. See perf_install_in_context(). 6215 */ 6216 if (!smp_load_acquire(&event->ctx)) 6217 continue; 6218 6219 if (event->state < PERF_EVENT_STATE_INACTIVE) 6220 continue; 6221 if (!event_filter_match(event)) 6222 continue; 6223 output(event, data); 6224 } 6225 } 6226 6227 /* 6228 * Iterate all events that need to receive side-band events. 6229 * 6230 * For new callers; ensure that account_pmu_sb_event() includes 6231 * your event, otherwise it might not get delivered. 6232 */ 6233 static void 6234 perf_iterate_sb(perf_iterate_f output, void *data, 6235 struct perf_event_context *task_ctx) 6236 { 6237 struct perf_event_context *ctx; 6238 int ctxn; 6239 6240 rcu_read_lock(); 6241 preempt_disable(); 6242 6243 /* 6244 * If we have task_ctx != NULL we only notify the task context itself. 6245 * The task_ctx is set only for EXIT events before releasing task 6246 * context. 6247 */ 6248 if (task_ctx) { 6249 perf_iterate_ctx(task_ctx, output, data, false); 6250 goto done; 6251 } 6252 6253 perf_iterate_sb_cpu(output, data); 6254 6255 for_each_task_context_nr(ctxn) { 6256 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); 6257 if (ctx) 6258 perf_iterate_ctx(ctx, output, data, false); 6259 } 6260 done: 6261 preempt_enable(); 6262 rcu_read_unlock(); 6263 } 6264 6265 /* 6266 * Clear all file-based filters at exec, they'll have to be 6267 * re-instated when/if these objects are mmapped again. 6268 */ 6269 static void perf_event_addr_filters_exec(struct perf_event *event, void *data) 6270 { 6271 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 6272 struct perf_addr_filter *filter; 6273 unsigned int restart = 0, count = 0; 6274 unsigned long flags; 6275 6276 if (!has_addr_filter(event)) 6277 return; 6278 6279 raw_spin_lock_irqsave(&ifh->lock, flags); 6280 list_for_each_entry(filter, &ifh->list, entry) { 6281 if (filter->inode) { 6282 event->addr_filters_offs[count] = 0; 6283 restart++; 6284 } 6285 6286 count++; 6287 } 6288 6289 if (restart) 6290 event->addr_filters_gen++; 6291 raw_spin_unlock_irqrestore(&ifh->lock, flags); 6292 6293 if (restart) 6294 perf_event_stop(event, 1); 6295 } 6296 6297 void perf_event_exec(void) 6298 { 6299 struct perf_event_context *ctx; 6300 int ctxn; 6301 6302 rcu_read_lock(); 6303 for_each_task_context_nr(ctxn) { 6304 ctx = current->perf_event_ctxp[ctxn]; 6305 if (!ctx) 6306 continue; 6307 6308 perf_event_enable_on_exec(ctxn); 6309 6310 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL, 6311 true); 6312 } 6313 rcu_read_unlock(); 6314 } 6315 6316 struct remote_output { 6317 struct ring_buffer *rb; 6318 int err; 6319 }; 6320 6321 static void __perf_event_output_stop(struct perf_event *event, void *data) 6322 { 6323 struct perf_event *parent = event->parent; 6324 struct remote_output *ro = data; 6325 struct ring_buffer *rb = ro->rb; 6326 struct stop_event_data sd = { 6327 .event = event, 6328 }; 6329 6330 if (!has_aux(event)) 6331 return; 6332 6333 if (!parent) 6334 parent = event; 6335 6336 /* 6337 * In case of inheritance, it will be the parent that links to the 6338 * ring-buffer, but it will be the child that's actually using it. 6339 * 6340 * We are using event::rb to determine if the event should be stopped, 6341 * however this may race with ring_buffer_attach() (through set_output), 6342 * which will make us skip the event that actually needs to be stopped. 6343 * So ring_buffer_attach() has to stop an aux event before re-assigning 6344 * its rb pointer. 6345 */ 6346 if (rcu_dereference(parent->rb) == rb) 6347 ro->err = __perf_event_stop(&sd); 6348 } 6349 6350 static int __perf_pmu_output_stop(void *info) 6351 { 6352 struct perf_event *event = info; 6353 struct pmu *pmu = event->pmu; 6354 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 6355 struct remote_output ro = { 6356 .rb = event->rb, 6357 }; 6358 6359 rcu_read_lock(); 6360 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false); 6361 if (cpuctx->task_ctx) 6362 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop, 6363 &ro, false); 6364 rcu_read_unlock(); 6365 6366 return ro.err; 6367 } 6368 6369 static void perf_pmu_output_stop(struct perf_event *event) 6370 { 6371 struct perf_event *iter; 6372 int err, cpu; 6373 6374 restart: 6375 rcu_read_lock(); 6376 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) { 6377 /* 6378 * For per-CPU events, we need to make sure that neither they 6379 * nor their children are running; for cpu==-1 events it's 6380 * sufficient to stop the event itself if it's active, since 6381 * it can't have children. 6382 */ 6383 cpu = iter->cpu; 6384 if (cpu == -1) 6385 cpu = READ_ONCE(iter->oncpu); 6386 6387 if (cpu == -1) 6388 continue; 6389 6390 err = cpu_function_call(cpu, __perf_pmu_output_stop, event); 6391 if (err == -EAGAIN) { 6392 rcu_read_unlock(); 6393 goto restart; 6394 } 6395 } 6396 rcu_read_unlock(); 6397 } 6398 6399 /* 6400 * task tracking -- fork/exit 6401 * 6402 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task 6403 */ 6404 6405 struct perf_task_event { 6406 struct task_struct *task; 6407 struct perf_event_context *task_ctx; 6408 6409 struct { 6410 struct perf_event_header header; 6411 6412 u32 pid; 6413 u32 ppid; 6414 u32 tid; 6415 u32 ptid; 6416 u64 time; 6417 } event_id; 6418 }; 6419 6420 static int perf_event_task_match(struct perf_event *event) 6421 { 6422 return event->attr.comm || event->attr.mmap || 6423 event->attr.mmap2 || event->attr.mmap_data || 6424 event->attr.task; 6425 } 6426 6427 static void perf_event_task_output(struct perf_event *event, 6428 void *data) 6429 { 6430 struct perf_task_event *task_event = data; 6431 struct perf_output_handle handle; 6432 struct perf_sample_data sample; 6433 struct task_struct *task = task_event->task; 6434 int ret, size = task_event->event_id.header.size; 6435 6436 if (!perf_event_task_match(event)) 6437 return; 6438 6439 perf_event_header__init_id(&task_event->event_id.header, &sample, event); 6440 6441 ret = perf_output_begin(&handle, event, 6442 task_event->event_id.header.size); 6443 if (ret) 6444 goto out; 6445 6446 task_event->event_id.pid = perf_event_pid(event, task); 6447 task_event->event_id.ppid = perf_event_pid(event, current); 6448 6449 task_event->event_id.tid = perf_event_tid(event, task); 6450 task_event->event_id.ptid = perf_event_tid(event, current); 6451 6452 task_event->event_id.time = perf_event_clock(event); 6453 6454 perf_output_put(&handle, task_event->event_id); 6455 6456 perf_event__output_id_sample(event, &handle, &sample); 6457 6458 perf_output_end(&handle); 6459 out: 6460 task_event->event_id.header.size = size; 6461 } 6462 6463 static void perf_event_task(struct task_struct *task, 6464 struct perf_event_context *task_ctx, 6465 int new) 6466 { 6467 struct perf_task_event task_event; 6468 6469 if (!atomic_read(&nr_comm_events) && 6470 !atomic_read(&nr_mmap_events) && 6471 !atomic_read(&nr_task_events)) 6472 return; 6473 6474 task_event = (struct perf_task_event){ 6475 .task = task, 6476 .task_ctx = task_ctx, 6477 .event_id = { 6478 .header = { 6479 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT, 6480 .misc = 0, 6481 .size = sizeof(task_event.event_id), 6482 }, 6483 /* .pid */ 6484 /* .ppid */ 6485 /* .tid */ 6486 /* .ptid */ 6487 /* .time */ 6488 }, 6489 }; 6490 6491 perf_iterate_sb(perf_event_task_output, 6492 &task_event, 6493 task_ctx); 6494 } 6495 6496 void perf_event_fork(struct task_struct *task) 6497 { 6498 perf_event_task(task, NULL, 1); 6499 perf_event_namespaces(task); 6500 } 6501 6502 /* 6503 * comm tracking 6504 */ 6505 6506 struct perf_comm_event { 6507 struct task_struct *task; 6508 char *comm; 6509 int comm_size; 6510 6511 struct { 6512 struct perf_event_header header; 6513 6514 u32 pid; 6515 u32 tid; 6516 } event_id; 6517 }; 6518 6519 static int perf_event_comm_match(struct perf_event *event) 6520 { 6521 return event->attr.comm; 6522 } 6523 6524 static void perf_event_comm_output(struct perf_event *event, 6525 void *data) 6526 { 6527 struct perf_comm_event *comm_event = data; 6528 struct perf_output_handle handle; 6529 struct perf_sample_data sample; 6530 int size = comm_event->event_id.header.size; 6531 int ret; 6532 6533 if (!perf_event_comm_match(event)) 6534 return; 6535 6536 perf_event_header__init_id(&comm_event->event_id.header, &sample, event); 6537 ret = perf_output_begin(&handle, event, 6538 comm_event->event_id.header.size); 6539 6540 if (ret) 6541 goto out; 6542 6543 comm_event->event_id.pid = perf_event_pid(event, comm_event->task); 6544 comm_event->event_id.tid = perf_event_tid(event, comm_event->task); 6545 6546 perf_output_put(&handle, comm_event->event_id); 6547 __output_copy(&handle, comm_event->comm, 6548 comm_event->comm_size); 6549 6550 perf_event__output_id_sample(event, &handle, &sample); 6551 6552 perf_output_end(&handle); 6553 out: 6554 comm_event->event_id.header.size = size; 6555 } 6556 6557 static void perf_event_comm_event(struct perf_comm_event *comm_event) 6558 { 6559 char comm[TASK_COMM_LEN]; 6560 unsigned int size; 6561 6562 memset(comm, 0, sizeof(comm)); 6563 strlcpy(comm, comm_event->task->comm, sizeof(comm)); 6564 size = ALIGN(strlen(comm)+1, sizeof(u64)); 6565 6566 comm_event->comm = comm; 6567 comm_event->comm_size = size; 6568 6569 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size; 6570 6571 perf_iterate_sb(perf_event_comm_output, 6572 comm_event, 6573 NULL); 6574 } 6575 6576 void perf_event_comm(struct task_struct *task, bool exec) 6577 { 6578 struct perf_comm_event comm_event; 6579 6580 if (!atomic_read(&nr_comm_events)) 6581 return; 6582 6583 comm_event = (struct perf_comm_event){ 6584 .task = task, 6585 /* .comm */ 6586 /* .comm_size */ 6587 .event_id = { 6588 .header = { 6589 .type = PERF_RECORD_COMM, 6590 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0, 6591 /* .size */ 6592 }, 6593 /* .pid */ 6594 /* .tid */ 6595 }, 6596 }; 6597 6598 perf_event_comm_event(&comm_event); 6599 } 6600 6601 /* 6602 * namespaces tracking 6603 */ 6604 6605 struct perf_namespaces_event { 6606 struct task_struct *task; 6607 6608 struct { 6609 struct perf_event_header header; 6610 6611 u32 pid; 6612 u32 tid; 6613 u64 nr_namespaces; 6614 struct perf_ns_link_info link_info[NR_NAMESPACES]; 6615 } event_id; 6616 }; 6617 6618 static int perf_event_namespaces_match(struct perf_event *event) 6619 { 6620 return event->attr.namespaces; 6621 } 6622 6623 static void perf_event_namespaces_output(struct perf_event *event, 6624 void *data) 6625 { 6626 struct perf_namespaces_event *namespaces_event = data; 6627 struct perf_output_handle handle; 6628 struct perf_sample_data sample; 6629 int ret; 6630 6631 if (!perf_event_namespaces_match(event)) 6632 return; 6633 6634 perf_event_header__init_id(&namespaces_event->event_id.header, 6635 &sample, event); 6636 ret = perf_output_begin(&handle, event, 6637 namespaces_event->event_id.header.size); 6638 if (ret) 6639 return; 6640 6641 namespaces_event->event_id.pid = perf_event_pid(event, 6642 namespaces_event->task); 6643 namespaces_event->event_id.tid = perf_event_tid(event, 6644 namespaces_event->task); 6645 6646 perf_output_put(&handle, namespaces_event->event_id); 6647 6648 perf_event__output_id_sample(event, &handle, &sample); 6649 6650 perf_output_end(&handle); 6651 } 6652 6653 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info, 6654 struct task_struct *task, 6655 const struct proc_ns_operations *ns_ops) 6656 { 6657 struct path ns_path; 6658 struct inode *ns_inode; 6659 void *error; 6660 6661 error = ns_get_path(&ns_path, task, ns_ops); 6662 if (!error) { 6663 ns_inode = ns_path.dentry->d_inode; 6664 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev); 6665 ns_link_info->ino = ns_inode->i_ino; 6666 } 6667 } 6668 6669 void perf_event_namespaces(struct task_struct *task) 6670 { 6671 struct perf_namespaces_event namespaces_event; 6672 struct perf_ns_link_info *ns_link_info; 6673 6674 if (!atomic_read(&nr_namespaces_events)) 6675 return; 6676 6677 namespaces_event = (struct perf_namespaces_event){ 6678 .task = task, 6679 .event_id = { 6680 .header = { 6681 .type = PERF_RECORD_NAMESPACES, 6682 .misc = 0, 6683 .size = sizeof(namespaces_event.event_id), 6684 }, 6685 /* .pid */ 6686 /* .tid */ 6687 .nr_namespaces = NR_NAMESPACES, 6688 /* .link_info[NR_NAMESPACES] */ 6689 }, 6690 }; 6691 6692 ns_link_info = namespaces_event.event_id.link_info; 6693 6694 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX], 6695 task, &mntns_operations); 6696 6697 #ifdef CONFIG_USER_NS 6698 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX], 6699 task, &userns_operations); 6700 #endif 6701 #ifdef CONFIG_NET_NS 6702 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX], 6703 task, &netns_operations); 6704 #endif 6705 #ifdef CONFIG_UTS_NS 6706 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX], 6707 task, &utsns_operations); 6708 #endif 6709 #ifdef CONFIG_IPC_NS 6710 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX], 6711 task, &ipcns_operations); 6712 #endif 6713 #ifdef CONFIG_PID_NS 6714 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX], 6715 task, &pidns_operations); 6716 #endif 6717 #ifdef CONFIG_CGROUPS 6718 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX], 6719 task, &cgroupns_operations); 6720 #endif 6721 6722 perf_iterate_sb(perf_event_namespaces_output, 6723 &namespaces_event, 6724 NULL); 6725 } 6726 6727 /* 6728 * mmap tracking 6729 */ 6730 6731 struct perf_mmap_event { 6732 struct vm_area_struct *vma; 6733 6734 const char *file_name; 6735 int file_size; 6736 int maj, min; 6737 u64 ino; 6738 u64 ino_generation; 6739 u32 prot, flags; 6740 6741 struct { 6742 struct perf_event_header header; 6743 6744 u32 pid; 6745 u32 tid; 6746 u64 start; 6747 u64 len; 6748 u64 pgoff; 6749 } event_id; 6750 }; 6751 6752 static int perf_event_mmap_match(struct perf_event *event, 6753 void *data) 6754 { 6755 struct perf_mmap_event *mmap_event = data; 6756 struct vm_area_struct *vma = mmap_event->vma; 6757 int executable = vma->vm_flags & VM_EXEC; 6758 6759 return (!executable && event->attr.mmap_data) || 6760 (executable && (event->attr.mmap || event->attr.mmap2)); 6761 } 6762 6763 static void perf_event_mmap_output(struct perf_event *event, 6764 void *data) 6765 { 6766 struct perf_mmap_event *mmap_event = data; 6767 struct perf_output_handle handle; 6768 struct perf_sample_data sample; 6769 int size = mmap_event->event_id.header.size; 6770 int ret; 6771 6772 if (!perf_event_mmap_match(event, data)) 6773 return; 6774 6775 if (event->attr.mmap2) { 6776 mmap_event->event_id.header.type = PERF_RECORD_MMAP2; 6777 mmap_event->event_id.header.size += sizeof(mmap_event->maj); 6778 mmap_event->event_id.header.size += sizeof(mmap_event->min); 6779 mmap_event->event_id.header.size += sizeof(mmap_event->ino); 6780 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation); 6781 mmap_event->event_id.header.size += sizeof(mmap_event->prot); 6782 mmap_event->event_id.header.size += sizeof(mmap_event->flags); 6783 } 6784 6785 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event); 6786 ret = perf_output_begin(&handle, event, 6787 mmap_event->event_id.header.size); 6788 if (ret) 6789 goto out; 6790 6791 mmap_event->event_id.pid = perf_event_pid(event, current); 6792 mmap_event->event_id.tid = perf_event_tid(event, current); 6793 6794 perf_output_put(&handle, mmap_event->event_id); 6795 6796 if (event->attr.mmap2) { 6797 perf_output_put(&handle, mmap_event->maj); 6798 perf_output_put(&handle, mmap_event->min); 6799 perf_output_put(&handle, mmap_event->ino); 6800 perf_output_put(&handle, mmap_event->ino_generation); 6801 perf_output_put(&handle, mmap_event->prot); 6802 perf_output_put(&handle, mmap_event->flags); 6803 } 6804 6805 __output_copy(&handle, mmap_event->file_name, 6806 mmap_event->file_size); 6807 6808 perf_event__output_id_sample(event, &handle, &sample); 6809 6810 perf_output_end(&handle); 6811 out: 6812 mmap_event->event_id.header.size = size; 6813 } 6814 6815 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) 6816 { 6817 struct vm_area_struct *vma = mmap_event->vma; 6818 struct file *file = vma->vm_file; 6819 int maj = 0, min = 0; 6820 u64 ino = 0, gen = 0; 6821 u32 prot = 0, flags = 0; 6822 unsigned int size; 6823 char tmp[16]; 6824 char *buf = NULL; 6825 char *name; 6826 6827 if (vma->vm_flags & VM_READ) 6828 prot |= PROT_READ; 6829 if (vma->vm_flags & VM_WRITE) 6830 prot |= PROT_WRITE; 6831 if (vma->vm_flags & VM_EXEC) 6832 prot |= PROT_EXEC; 6833 6834 if (vma->vm_flags & VM_MAYSHARE) 6835 flags = MAP_SHARED; 6836 else 6837 flags = MAP_PRIVATE; 6838 6839 if (vma->vm_flags & VM_DENYWRITE) 6840 flags |= MAP_DENYWRITE; 6841 if (vma->vm_flags & VM_MAYEXEC) 6842 flags |= MAP_EXECUTABLE; 6843 if (vma->vm_flags & VM_LOCKED) 6844 flags |= MAP_LOCKED; 6845 if (vma->vm_flags & VM_HUGETLB) 6846 flags |= MAP_HUGETLB; 6847 6848 if (file) { 6849 struct inode *inode; 6850 dev_t dev; 6851 6852 buf = kmalloc(PATH_MAX, GFP_KERNEL); 6853 if (!buf) { 6854 name = "//enomem"; 6855 goto cpy_name; 6856 } 6857 /* 6858 * d_path() works from the end of the rb backwards, so we 6859 * need to add enough zero bytes after the string to handle 6860 * the 64bit alignment we do later. 6861 */ 6862 name = file_path(file, buf, PATH_MAX - sizeof(u64)); 6863 if (IS_ERR(name)) { 6864 name = "//toolong"; 6865 goto cpy_name; 6866 } 6867 inode = file_inode(vma->vm_file); 6868 dev = inode->i_sb->s_dev; 6869 ino = inode->i_ino; 6870 gen = inode->i_generation; 6871 maj = MAJOR(dev); 6872 min = MINOR(dev); 6873 6874 goto got_name; 6875 } else { 6876 if (vma->vm_ops && vma->vm_ops->name) { 6877 name = (char *) vma->vm_ops->name(vma); 6878 if (name) 6879 goto cpy_name; 6880 } 6881 6882 name = (char *)arch_vma_name(vma); 6883 if (name) 6884 goto cpy_name; 6885 6886 if (vma->vm_start <= vma->vm_mm->start_brk && 6887 vma->vm_end >= vma->vm_mm->brk) { 6888 name = "[heap]"; 6889 goto cpy_name; 6890 } 6891 if (vma->vm_start <= vma->vm_mm->start_stack && 6892 vma->vm_end >= vma->vm_mm->start_stack) { 6893 name = "[stack]"; 6894 goto cpy_name; 6895 } 6896 6897 name = "//anon"; 6898 goto cpy_name; 6899 } 6900 6901 cpy_name: 6902 strlcpy(tmp, name, sizeof(tmp)); 6903 name = tmp; 6904 got_name: 6905 /* 6906 * Since our buffer works in 8 byte units we need to align our string 6907 * size to a multiple of 8. However, we must guarantee the tail end is 6908 * zero'd out to avoid leaking random bits to userspace. 6909 */ 6910 size = strlen(name)+1; 6911 while (!IS_ALIGNED(size, sizeof(u64))) 6912 name[size++] = '\0'; 6913 6914 mmap_event->file_name = name; 6915 mmap_event->file_size = size; 6916 mmap_event->maj = maj; 6917 mmap_event->min = min; 6918 mmap_event->ino = ino; 6919 mmap_event->ino_generation = gen; 6920 mmap_event->prot = prot; 6921 mmap_event->flags = flags; 6922 6923 if (!(vma->vm_flags & VM_EXEC)) 6924 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA; 6925 6926 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size; 6927 6928 perf_iterate_sb(perf_event_mmap_output, 6929 mmap_event, 6930 NULL); 6931 6932 kfree(buf); 6933 } 6934 6935 /* 6936 * Check whether inode and address range match filter criteria. 6937 */ 6938 static bool perf_addr_filter_match(struct perf_addr_filter *filter, 6939 struct file *file, unsigned long offset, 6940 unsigned long size) 6941 { 6942 if (filter->inode != file_inode(file)) 6943 return false; 6944 6945 if (filter->offset > offset + size) 6946 return false; 6947 6948 if (filter->offset + filter->size < offset) 6949 return false; 6950 6951 return true; 6952 } 6953 6954 static void __perf_addr_filters_adjust(struct perf_event *event, void *data) 6955 { 6956 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 6957 struct vm_area_struct *vma = data; 6958 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags; 6959 struct file *file = vma->vm_file; 6960 struct perf_addr_filter *filter; 6961 unsigned int restart = 0, count = 0; 6962 6963 if (!has_addr_filter(event)) 6964 return; 6965 6966 if (!file) 6967 return; 6968 6969 raw_spin_lock_irqsave(&ifh->lock, flags); 6970 list_for_each_entry(filter, &ifh->list, entry) { 6971 if (perf_addr_filter_match(filter, file, off, 6972 vma->vm_end - vma->vm_start)) { 6973 event->addr_filters_offs[count] = vma->vm_start; 6974 restart++; 6975 } 6976 6977 count++; 6978 } 6979 6980 if (restart) 6981 event->addr_filters_gen++; 6982 raw_spin_unlock_irqrestore(&ifh->lock, flags); 6983 6984 if (restart) 6985 perf_event_stop(event, 1); 6986 } 6987 6988 /* 6989 * Adjust all task's events' filters to the new vma 6990 */ 6991 static void perf_addr_filters_adjust(struct vm_area_struct *vma) 6992 { 6993 struct perf_event_context *ctx; 6994 int ctxn; 6995 6996 /* 6997 * Data tracing isn't supported yet and as such there is no need 6998 * to keep track of anything that isn't related to executable code: 6999 */ 7000 if (!(vma->vm_flags & VM_EXEC)) 7001 return; 7002 7003 rcu_read_lock(); 7004 for_each_task_context_nr(ctxn) { 7005 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); 7006 if (!ctx) 7007 continue; 7008 7009 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true); 7010 } 7011 rcu_read_unlock(); 7012 } 7013 7014 void perf_event_mmap(struct vm_area_struct *vma) 7015 { 7016 struct perf_mmap_event mmap_event; 7017 7018 if (!atomic_read(&nr_mmap_events)) 7019 return; 7020 7021 mmap_event = (struct perf_mmap_event){ 7022 .vma = vma, 7023 /* .file_name */ 7024 /* .file_size */ 7025 .event_id = { 7026 .header = { 7027 .type = PERF_RECORD_MMAP, 7028 .misc = PERF_RECORD_MISC_USER, 7029 /* .size */ 7030 }, 7031 /* .pid */ 7032 /* .tid */ 7033 .start = vma->vm_start, 7034 .len = vma->vm_end - vma->vm_start, 7035 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT, 7036 }, 7037 /* .maj (attr_mmap2 only) */ 7038 /* .min (attr_mmap2 only) */ 7039 /* .ino (attr_mmap2 only) */ 7040 /* .ino_generation (attr_mmap2 only) */ 7041 /* .prot (attr_mmap2 only) */ 7042 /* .flags (attr_mmap2 only) */ 7043 }; 7044 7045 perf_addr_filters_adjust(vma); 7046 perf_event_mmap_event(&mmap_event); 7047 } 7048 7049 void perf_event_aux_event(struct perf_event *event, unsigned long head, 7050 unsigned long size, u64 flags) 7051 { 7052 struct perf_output_handle handle; 7053 struct perf_sample_data sample; 7054 struct perf_aux_event { 7055 struct perf_event_header header; 7056 u64 offset; 7057 u64 size; 7058 u64 flags; 7059 } rec = { 7060 .header = { 7061 .type = PERF_RECORD_AUX, 7062 .misc = 0, 7063 .size = sizeof(rec), 7064 }, 7065 .offset = head, 7066 .size = size, 7067 .flags = flags, 7068 }; 7069 int ret; 7070 7071 perf_event_header__init_id(&rec.header, &sample, event); 7072 ret = perf_output_begin(&handle, event, rec.header.size); 7073 7074 if (ret) 7075 return; 7076 7077 perf_output_put(&handle, rec); 7078 perf_event__output_id_sample(event, &handle, &sample); 7079 7080 perf_output_end(&handle); 7081 } 7082 7083 /* 7084 * Lost/dropped samples logging 7085 */ 7086 void perf_log_lost_samples(struct perf_event *event, u64 lost) 7087 { 7088 struct perf_output_handle handle; 7089 struct perf_sample_data sample; 7090 int ret; 7091 7092 struct { 7093 struct perf_event_header header; 7094 u64 lost; 7095 } lost_samples_event = { 7096 .header = { 7097 .type = PERF_RECORD_LOST_SAMPLES, 7098 .misc = 0, 7099 .size = sizeof(lost_samples_event), 7100 }, 7101 .lost = lost, 7102 }; 7103 7104 perf_event_header__init_id(&lost_samples_event.header, &sample, event); 7105 7106 ret = perf_output_begin(&handle, event, 7107 lost_samples_event.header.size); 7108 if (ret) 7109 return; 7110 7111 perf_output_put(&handle, lost_samples_event); 7112 perf_event__output_id_sample(event, &handle, &sample); 7113 perf_output_end(&handle); 7114 } 7115 7116 /* 7117 * context_switch tracking 7118 */ 7119 7120 struct perf_switch_event { 7121 struct task_struct *task; 7122 struct task_struct *next_prev; 7123 7124 struct { 7125 struct perf_event_header header; 7126 u32 next_prev_pid; 7127 u32 next_prev_tid; 7128 } event_id; 7129 }; 7130 7131 static int perf_event_switch_match(struct perf_event *event) 7132 { 7133 return event->attr.context_switch; 7134 } 7135 7136 static void perf_event_switch_output(struct perf_event *event, void *data) 7137 { 7138 struct perf_switch_event *se = data; 7139 struct perf_output_handle handle; 7140 struct perf_sample_data sample; 7141 int ret; 7142 7143 if (!perf_event_switch_match(event)) 7144 return; 7145 7146 /* Only CPU-wide events are allowed to see next/prev pid/tid */ 7147 if (event->ctx->task) { 7148 se->event_id.header.type = PERF_RECORD_SWITCH; 7149 se->event_id.header.size = sizeof(se->event_id.header); 7150 } else { 7151 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE; 7152 se->event_id.header.size = sizeof(se->event_id); 7153 se->event_id.next_prev_pid = 7154 perf_event_pid(event, se->next_prev); 7155 se->event_id.next_prev_tid = 7156 perf_event_tid(event, se->next_prev); 7157 } 7158 7159 perf_event_header__init_id(&se->event_id.header, &sample, event); 7160 7161 ret = perf_output_begin(&handle, event, se->event_id.header.size); 7162 if (ret) 7163 return; 7164 7165 if (event->ctx->task) 7166 perf_output_put(&handle, se->event_id.header); 7167 else 7168 perf_output_put(&handle, se->event_id); 7169 7170 perf_event__output_id_sample(event, &handle, &sample); 7171 7172 perf_output_end(&handle); 7173 } 7174 7175 static void perf_event_switch(struct task_struct *task, 7176 struct task_struct *next_prev, bool sched_in) 7177 { 7178 struct perf_switch_event switch_event; 7179 7180 /* N.B. caller checks nr_switch_events != 0 */ 7181 7182 switch_event = (struct perf_switch_event){ 7183 .task = task, 7184 .next_prev = next_prev, 7185 .event_id = { 7186 .header = { 7187 /* .type */ 7188 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT, 7189 /* .size */ 7190 }, 7191 /* .next_prev_pid */ 7192 /* .next_prev_tid */ 7193 }, 7194 }; 7195 7196 perf_iterate_sb(perf_event_switch_output, 7197 &switch_event, 7198 NULL); 7199 } 7200 7201 /* 7202 * IRQ throttle logging 7203 */ 7204 7205 static void perf_log_throttle(struct perf_event *event, int enable) 7206 { 7207 struct perf_output_handle handle; 7208 struct perf_sample_data sample; 7209 int ret; 7210 7211 struct { 7212 struct perf_event_header header; 7213 u64 time; 7214 u64 id; 7215 u64 stream_id; 7216 } throttle_event = { 7217 .header = { 7218 .type = PERF_RECORD_THROTTLE, 7219 .misc = 0, 7220 .size = sizeof(throttle_event), 7221 }, 7222 .time = perf_event_clock(event), 7223 .id = primary_event_id(event), 7224 .stream_id = event->id, 7225 }; 7226 7227 if (enable) 7228 throttle_event.header.type = PERF_RECORD_UNTHROTTLE; 7229 7230 perf_event_header__init_id(&throttle_event.header, &sample, event); 7231 7232 ret = perf_output_begin(&handle, event, 7233 throttle_event.header.size); 7234 if (ret) 7235 return; 7236 7237 perf_output_put(&handle, throttle_event); 7238 perf_event__output_id_sample(event, &handle, &sample); 7239 perf_output_end(&handle); 7240 } 7241 7242 static void perf_log_itrace_start(struct perf_event *event) 7243 { 7244 struct perf_output_handle handle; 7245 struct perf_sample_data sample; 7246 struct perf_aux_event { 7247 struct perf_event_header header; 7248 u32 pid; 7249 u32 tid; 7250 } rec; 7251 int ret; 7252 7253 if (event->parent) 7254 event = event->parent; 7255 7256 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) || 7257 event->hw.itrace_started) 7258 return; 7259 7260 rec.header.type = PERF_RECORD_ITRACE_START; 7261 rec.header.misc = 0; 7262 rec.header.size = sizeof(rec); 7263 rec.pid = perf_event_pid(event, current); 7264 rec.tid = perf_event_tid(event, current); 7265 7266 perf_event_header__init_id(&rec.header, &sample, event); 7267 ret = perf_output_begin(&handle, event, rec.header.size); 7268 7269 if (ret) 7270 return; 7271 7272 perf_output_put(&handle, rec); 7273 perf_event__output_id_sample(event, &handle, &sample); 7274 7275 perf_output_end(&handle); 7276 } 7277 7278 static int 7279 __perf_event_account_interrupt(struct perf_event *event, int throttle) 7280 { 7281 struct hw_perf_event *hwc = &event->hw; 7282 int ret = 0; 7283 u64 seq; 7284 7285 seq = __this_cpu_read(perf_throttled_seq); 7286 if (seq != hwc->interrupts_seq) { 7287 hwc->interrupts_seq = seq; 7288 hwc->interrupts = 1; 7289 } else { 7290 hwc->interrupts++; 7291 if (unlikely(throttle 7292 && hwc->interrupts >= max_samples_per_tick)) { 7293 __this_cpu_inc(perf_throttled_count); 7294 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); 7295 hwc->interrupts = MAX_INTERRUPTS; 7296 perf_log_throttle(event, 0); 7297 ret = 1; 7298 } 7299 } 7300 7301 if (event->attr.freq) { 7302 u64 now = perf_clock(); 7303 s64 delta = now - hwc->freq_time_stamp; 7304 7305 hwc->freq_time_stamp = now; 7306 7307 if (delta > 0 && delta < 2*TICK_NSEC) 7308 perf_adjust_period(event, delta, hwc->last_period, true); 7309 } 7310 7311 return ret; 7312 } 7313 7314 int perf_event_account_interrupt(struct perf_event *event) 7315 { 7316 return __perf_event_account_interrupt(event, 1); 7317 } 7318 7319 static bool sample_is_allowed(struct perf_event *event, struct pt_regs *regs) 7320 { 7321 /* 7322 * Due to interrupt latency (AKA "skid"), we may enter the 7323 * kernel before taking an overflow, even if the PMU is only 7324 * counting user events. 7325 * To avoid leaking information to userspace, we must always 7326 * reject kernel samples when exclude_kernel is set. 7327 */ 7328 if (event->attr.exclude_kernel && !user_mode(regs)) 7329 return false; 7330 7331 return true; 7332 } 7333 7334 /* 7335 * Generic event overflow handling, sampling. 7336 */ 7337 7338 static int __perf_event_overflow(struct perf_event *event, 7339 int throttle, struct perf_sample_data *data, 7340 struct pt_regs *regs) 7341 { 7342 int events = atomic_read(&event->event_limit); 7343 int ret = 0; 7344 7345 /* 7346 * Non-sampling counters might still use the PMI to fold short 7347 * hardware counters, ignore those. 7348 */ 7349 if (unlikely(!is_sampling_event(event))) 7350 return 0; 7351 7352 ret = __perf_event_account_interrupt(event, throttle); 7353 7354 /* 7355 * For security, drop the skid kernel samples if necessary. 7356 */ 7357 if (!sample_is_allowed(event, regs)) 7358 return ret; 7359 7360 /* 7361 * XXX event_limit might not quite work as expected on inherited 7362 * events 7363 */ 7364 7365 event->pending_kill = POLL_IN; 7366 if (events && atomic_dec_and_test(&event->event_limit)) { 7367 ret = 1; 7368 event->pending_kill = POLL_HUP; 7369 7370 perf_event_disable_inatomic(event); 7371 } 7372 7373 READ_ONCE(event->overflow_handler)(event, data, regs); 7374 7375 if (*perf_event_fasync(event) && event->pending_kill) { 7376 event->pending_wakeup = 1; 7377 irq_work_queue(&event->pending); 7378 } 7379 7380 return ret; 7381 } 7382 7383 int perf_event_overflow(struct perf_event *event, 7384 struct perf_sample_data *data, 7385 struct pt_regs *regs) 7386 { 7387 return __perf_event_overflow(event, 1, data, regs); 7388 } 7389 7390 /* 7391 * Generic software event infrastructure 7392 */ 7393 7394 struct swevent_htable { 7395 struct swevent_hlist *swevent_hlist; 7396 struct mutex hlist_mutex; 7397 int hlist_refcount; 7398 7399 /* Recursion avoidance in each contexts */ 7400 int recursion[PERF_NR_CONTEXTS]; 7401 }; 7402 7403 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable); 7404 7405 /* 7406 * We directly increment event->count and keep a second value in 7407 * event->hw.period_left to count intervals. This period event 7408 * is kept in the range [-sample_period, 0] so that we can use the 7409 * sign as trigger. 7410 */ 7411 7412 u64 perf_swevent_set_period(struct perf_event *event) 7413 { 7414 struct hw_perf_event *hwc = &event->hw; 7415 u64 period = hwc->last_period; 7416 u64 nr, offset; 7417 s64 old, val; 7418 7419 hwc->last_period = hwc->sample_period; 7420 7421 again: 7422 old = val = local64_read(&hwc->period_left); 7423 if (val < 0) 7424 return 0; 7425 7426 nr = div64_u64(period + val, period); 7427 offset = nr * period; 7428 val -= offset; 7429 if (local64_cmpxchg(&hwc->period_left, old, val) != old) 7430 goto again; 7431 7432 return nr; 7433 } 7434 7435 static void perf_swevent_overflow(struct perf_event *event, u64 overflow, 7436 struct perf_sample_data *data, 7437 struct pt_regs *regs) 7438 { 7439 struct hw_perf_event *hwc = &event->hw; 7440 int throttle = 0; 7441 7442 if (!overflow) 7443 overflow = perf_swevent_set_period(event); 7444 7445 if (hwc->interrupts == MAX_INTERRUPTS) 7446 return; 7447 7448 for (; overflow; overflow--) { 7449 if (__perf_event_overflow(event, throttle, 7450 data, regs)) { 7451 /* 7452 * We inhibit the overflow from happening when 7453 * hwc->interrupts == MAX_INTERRUPTS. 7454 */ 7455 break; 7456 } 7457 throttle = 1; 7458 } 7459 } 7460 7461 static void perf_swevent_event(struct perf_event *event, u64 nr, 7462 struct perf_sample_data *data, 7463 struct pt_regs *regs) 7464 { 7465 struct hw_perf_event *hwc = &event->hw; 7466 7467 local64_add(nr, &event->count); 7468 7469 if (!regs) 7470 return; 7471 7472 if (!is_sampling_event(event)) 7473 return; 7474 7475 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) { 7476 data->period = nr; 7477 return perf_swevent_overflow(event, 1, data, regs); 7478 } else 7479 data->period = event->hw.last_period; 7480 7481 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq) 7482 return perf_swevent_overflow(event, 1, data, regs); 7483 7484 if (local64_add_negative(nr, &hwc->period_left)) 7485 return; 7486 7487 perf_swevent_overflow(event, 0, data, regs); 7488 } 7489 7490 static int perf_exclude_event(struct perf_event *event, 7491 struct pt_regs *regs) 7492 { 7493 if (event->hw.state & PERF_HES_STOPPED) 7494 return 1; 7495 7496 if (regs) { 7497 if (event->attr.exclude_user && user_mode(regs)) 7498 return 1; 7499 7500 if (event->attr.exclude_kernel && !user_mode(regs)) 7501 return 1; 7502 } 7503 7504 return 0; 7505 } 7506 7507 static int perf_swevent_match(struct perf_event *event, 7508 enum perf_type_id type, 7509 u32 event_id, 7510 struct perf_sample_data *data, 7511 struct pt_regs *regs) 7512 { 7513 if (event->attr.type != type) 7514 return 0; 7515 7516 if (event->attr.config != event_id) 7517 return 0; 7518 7519 if (perf_exclude_event(event, regs)) 7520 return 0; 7521 7522 return 1; 7523 } 7524 7525 static inline u64 swevent_hash(u64 type, u32 event_id) 7526 { 7527 u64 val = event_id | (type << 32); 7528 7529 return hash_64(val, SWEVENT_HLIST_BITS); 7530 } 7531 7532 static inline struct hlist_head * 7533 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id) 7534 { 7535 u64 hash = swevent_hash(type, event_id); 7536 7537 return &hlist->heads[hash]; 7538 } 7539 7540 /* For the read side: events when they trigger */ 7541 static inline struct hlist_head * 7542 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id) 7543 { 7544 struct swevent_hlist *hlist; 7545 7546 hlist = rcu_dereference(swhash->swevent_hlist); 7547 if (!hlist) 7548 return NULL; 7549 7550 return __find_swevent_head(hlist, type, event_id); 7551 } 7552 7553 /* For the event head insertion and removal in the hlist */ 7554 static inline struct hlist_head * 7555 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event) 7556 { 7557 struct swevent_hlist *hlist; 7558 u32 event_id = event->attr.config; 7559 u64 type = event->attr.type; 7560 7561 /* 7562 * Event scheduling is always serialized against hlist allocation 7563 * and release. Which makes the protected version suitable here. 7564 * The context lock guarantees that. 7565 */ 7566 hlist = rcu_dereference_protected(swhash->swevent_hlist, 7567 lockdep_is_held(&event->ctx->lock)); 7568 if (!hlist) 7569 return NULL; 7570 7571 return __find_swevent_head(hlist, type, event_id); 7572 } 7573 7574 static void do_perf_sw_event(enum perf_type_id type, u32 event_id, 7575 u64 nr, 7576 struct perf_sample_data *data, 7577 struct pt_regs *regs) 7578 { 7579 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 7580 struct perf_event *event; 7581 struct hlist_head *head; 7582 7583 rcu_read_lock(); 7584 head = find_swevent_head_rcu(swhash, type, event_id); 7585 if (!head) 7586 goto end; 7587 7588 hlist_for_each_entry_rcu(event, head, hlist_entry) { 7589 if (perf_swevent_match(event, type, event_id, data, regs)) 7590 perf_swevent_event(event, nr, data, regs); 7591 } 7592 end: 7593 rcu_read_unlock(); 7594 } 7595 7596 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]); 7597 7598 int perf_swevent_get_recursion_context(void) 7599 { 7600 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 7601 7602 return get_recursion_context(swhash->recursion); 7603 } 7604 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context); 7605 7606 void perf_swevent_put_recursion_context(int rctx) 7607 { 7608 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 7609 7610 put_recursion_context(swhash->recursion, rctx); 7611 } 7612 7613 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) 7614 { 7615 struct perf_sample_data data; 7616 7617 if (WARN_ON_ONCE(!regs)) 7618 return; 7619 7620 perf_sample_data_init(&data, addr, 0); 7621 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs); 7622 } 7623 7624 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) 7625 { 7626 int rctx; 7627 7628 preempt_disable_notrace(); 7629 rctx = perf_swevent_get_recursion_context(); 7630 if (unlikely(rctx < 0)) 7631 goto fail; 7632 7633 ___perf_sw_event(event_id, nr, regs, addr); 7634 7635 perf_swevent_put_recursion_context(rctx); 7636 fail: 7637 preempt_enable_notrace(); 7638 } 7639 7640 static void perf_swevent_read(struct perf_event *event) 7641 { 7642 } 7643 7644 static int perf_swevent_add(struct perf_event *event, int flags) 7645 { 7646 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 7647 struct hw_perf_event *hwc = &event->hw; 7648 struct hlist_head *head; 7649 7650 if (is_sampling_event(event)) { 7651 hwc->last_period = hwc->sample_period; 7652 perf_swevent_set_period(event); 7653 } 7654 7655 hwc->state = !(flags & PERF_EF_START); 7656 7657 head = find_swevent_head(swhash, event); 7658 if (WARN_ON_ONCE(!head)) 7659 return -EINVAL; 7660 7661 hlist_add_head_rcu(&event->hlist_entry, head); 7662 perf_event_update_userpage(event); 7663 7664 return 0; 7665 } 7666 7667 static void perf_swevent_del(struct perf_event *event, int flags) 7668 { 7669 hlist_del_rcu(&event->hlist_entry); 7670 } 7671 7672 static void perf_swevent_start(struct perf_event *event, int flags) 7673 { 7674 event->hw.state = 0; 7675 } 7676 7677 static void perf_swevent_stop(struct perf_event *event, int flags) 7678 { 7679 event->hw.state = PERF_HES_STOPPED; 7680 } 7681 7682 /* Deref the hlist from the update side */ 7683 static inline struct swevent_hlist * 7684 swevent_hlist_deref(struct swevent_htable *swhash) 7685 { 7686 return rcu_dereference_protected(swhash->swevent_hlist, 7687 lockdep_is_held(&swhash->hlist_mutex)); 7688 } 7689 7690 static void swevent_hlist_release(struct swevent_htable *swhash) 7691 { 7692 struct swevent_hlist *hlist = swevent_hlist_deref(swhash); 7693 7694 if (!hlist) 7695 return; 7696 7697 RCU_INIT_POINTER(swhash->swevent_hlist, NULL); 7698 kfree_rcu(hlist, rcu_head); 7699 } 7700 7701 static void swevent_hlist_put_cpu(int cpu) 7702 { 7703 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 7704 7705 mutex_lock(&swhash->hlist_mutex); 7706 7707 if (!--swhash->hlist_refcount) 7708 swevent_hlist_release(swhash); 7709 7710 mutex_unlock(&swhash->hlist_mutex); 7711 } 7712 7713 static void swevent_hlist_put(void) 7714 { 7715 int cpu; 7716 7717 for_each_possible_cpu(cpu) 7718 swevent_hlist_put_cpu(cpu); 7719 } 7720 7721 static int swevent_hlist_get_cpu(int cpu) 7722 { 7723 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 7724 int err = 0; 7725 7726 mutex_lock(&swhash->hlist_mutex); 7727 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) { 7728 struct swevent_hlist *hlist; 7729 7730 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL); 7731 if (!hlist) { 7732 err = -ENOMEM; 7733 goto exit; 7734 } 7735 rcu_assign_pointer(swhash->swevent_hlist, hlist); 7736 } 7737 swhash->hlist_refcount++; 7738 exit: 7739 mutex_unlock(&swhash->hlist_mutex); 7740 7741 return err; 7742 } 7743 7744 static int swevent_hlist_get(void) 7745 { 7746 int err, cpu, failed_cpu; 7747 7748 get_online_cpus(); 7749 for_each_possible_cpu(cpu) { 7750 err = swevent_hlist_get_cpu(cpu); 7751 if (err) { 7752 failed_cpu = cpu; 7753 goto fail; 7754 } 7755 } 7756 put_online_cpus(); 7757 7758 return 0; 7759 fail: 7760 for_each_possible_cpu(cpu) { 7761 if (cpu == failed_cpu) 7762 break; 7763 swevent_hlist_put_cpu(cpu); 7764 } 7765 7766 put_online_cpus(); 7767 return err; 7768 } 7769 7770 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX]; 7771 7772 static void sw_perf_event_destroy(struct perf_event *event) 7773 { 7774 u64 event_id = event->attr.config; 7775 7776 WARN_ON(event->parent); 7777 7778 static_key_slow_dec(&perf_swevent_enabled[event_id]); 7779 swevent_hlist_put(); 7780 } 7781 7782 static int perf_swevent_init(struct perf_event *event) 7783 { 7784 u64 event_id = event->attr.config; 7785 7786 if (event->attr.type != PERF_TYPE_SOFTWARE) 7787 return -ENOENT; 7788 7789 /* 7790 * no branch sampling for software events 7791 */ 7792 if (has_branch_stack(event)) 7793 return -EOPNOTSUPP; 7794 7795 switch (event_id) { 7796 case PERF_COUNT_SW_CPU_CLOCK: 7797 case PERF_COUNT_SW_TASK_CLOCK: 7798 return -ENOENT; 7799 7800 default: 7801 break; 7802 } 7803 7804 if (event_id >= PERF_COUNT_SW_MAX) 7805 return -ENOENT; 7806 7807 if (!event->parent) { 7808 int err; 7809 7810 err = swevent_hlist_get(); 7811 if (err) 7812 return err; 7813 7814 static_key_slow_inc(&perf_swevent_enabled[event_id]); 7815 event->destroy = sw_perf_event_destroy; 7816 } 7817 7818 return 0; 7819 } 7820 7821 static struct pmu perf_swevent = { 7822 .task_ctx_nr = perf_sw_context, 7823 7824 .capabilities = PERF_PMU_CAP_NO_NMI, 7825 7826 .event_init = perf_swevent_init, 7827 .add = perf_swevent_add, 7828 .del = perf_swevent_del, 7829 .start = perf_swevent_start, 7830 .stop = perf_swevent_stop, 7831 .read = perf_swevent_read, 7832 }; 7833 7834 #ifdef CONFIG_EVENT_TRACING 7835 7836 static int perf_tp_filter_match(struct perf_event *event, 7837 struct perf_sample_data *data) 7838 { 7839 void *record = data->raw->frag.data; 7840 7841 /* only top level events have filters set */ 7842 if (event->parent) 7843 event = event->parent; 7844 7845 if (likely(!event->filter) || filter_match_preds(event->filter, record)) 7846 return 1; 7847 return 0; 7848 } 7849 7850 static int perf_tp_event_match(struct perf_event *event, 7851 struct perf_sample_data *data, 7852 struct pt_regs *regs) 7853 { 7854 if (event->hw.state & PERF_HES_STOPPED) 7855 return 0; 7856 /* 7857 * All tracepoints are from kernel-space. 7858 */ 7859 if (event->attr.exclude_kernel) 7860 return 0; 7861 7862 if (!perf_tp_filter_match(event, data)) 7863 return 0; 7864 7865 return 1; 7866 } 7867 7868 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx, 7869 struct trace_event_call *call, u64 count, 7870 struct pt_regs *regs, struct hlist_head *head, 7871 struct task_struct *task) 7872 { 7873 struct bpf_prog *prog = call->prog; 7874 7875 if (prog) { 7876 *(struct pt_regs **)raw_data = regs; 7877 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) { 7878 perf_swevent_put_recursion_context(rctx); 7879 return; 7880 } 7881 } 7882 perf_tp_event(call->event.type, count, raw_data, size, regs, head, 7883 rctx, task); 7884 } 7885 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit); 7886 7887 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size, 7888 struct pt_regs *regs, struct hlist_head *head, int rctx, 7889 struct task_struct *task) 7890 { 7891 struct perf_sample_data data; 7892 struct perf_event *event; 7893 7894 struct perf_raw_record raw = { 7895 .frag = { 7896 .size = entry_size, 7897 .data = record, 7898 }, 7899 }; 7900 7901 perf_sample_data_init(&data, 0, 0); 7902 data.raw = &raw; 7903 7904 perf_trace_buf_update(record, event_type); 7905 7906 hlist_for_each_entry_rcu(event, head, hlist_entry) { 7907 if (perf_tp_event_match(event, &data, regs)) 7908 perf_swevent_event(event, count, &data, regs); 7909 } 7910 7911 /* 7912 * If we got specified a target task, also iterate its context and 7913 * deliver this event there too. 7914 */ 7915 if (task && task != current) { 7916 struct perf_event_context *ctx; 7917 struct trace_entry *entry = record; 7918 7919 rcu_read_lock(); 7920 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]); 7921 if (!ctx) 7922 goto unlock; 7923 7924 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 7925 if (event->attr.type != PERF_TYPE_TRACEPOINT) 7926 continue; 7927 if (event->attr.config != entry->type) 7928 continue; 7929 if (perf_tp_event_match(event, &data, regs)) 7930 perf_swevent_event(event, count, &data, regs); 7931 } 7932 unlock: 7933 rcu_read_unlock(); 7934 } 7935 7936 perf_swevent_put_recursion_context(rctx); 7937 } 7938 EXPORT_SYMBOL_GPL(perf_tp_event); 7939 7940 static void tp_perf_event_destroy(struct perf_event *event) 7941 { 7942 perf_trace_destroy(event); 7943 } 7944 7945 static int perf_tp_event_init(struct perf_event *event) 7946 { 7947 int err; 7948 7949 if (event->attr.type != PERF_TYPE_TRACEPOINT) 7950 return -ENOENT; 7951 7952 /* 7953 * no branch sampling for tracepoint events 7954 */ 7955 if (has_branch_stack(event)) 7956 return -EOPNOTSUPP; 7957 7958 err = perf_trace_init(event); 7959 if (err) 7960 return err; 7961 7962 event->destroy = tp_perf_event_destroy; 7963 7964 return 0; 7965 } 7966 7967 static struct pmu perf_tracepoint = { 7968 .task_ctx_nr = perf_sw_context, 7969 7970 .event_init = perf_tp_event_init, 7971 .add = perf_trace_add, 7972 .del = perf_trace_del, 7973 .start = perf_swevent_start, 7974 .stop = perf_swevent_stop, 7975 .read = perf_swevent_read, 7976 }; 7977 7978 static inline void perf_tp_register(void) 7979 { 7980 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT); 7981 } 7982 7983 static void perf_event_free_filter(struct perf_event *event) 7984 { 7985 ftrace_profile_free_filter(event); 7986 } 7987 7988 #ifdef CONFIG_BPF_SYSCALL 7989 static void bpf_overflow_handler(struct perf_event *event, 7990 struct perf_sample_data *data, 7991 struct pt_regs *regs) 7992 { 7993 struct bpf_perf_event_data_kern ctx = { 7994 .data = data, 7995 .regs = regs, 7996 }; 7997 int ret = 0; 7998 7999 preempt_disable(); 8000 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) 8001 goto out; 8002 rcu_read_lock(); 8003 ret = BPF_PROG_RUN(event->prog, &ctx); 8004 rcu_read_unlock(); 8005 out: 8006 __this_cpu_dec(bpf_prog_active); 8007 preempt_enable(); 8008 if (!ret) 8009 return; 8010 8011 event->orig_overflow_handler(event, data, regs); 8012 } 8013 8014 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd) 8015 { 8016 struct bpf_prog *prog; 8017 8018 if (event->overflow_handler_context) 8019 /* hw breakpoint or kernel counter */ 8020 return -EINVAL; 8021 8022 if (event->prog) 8023 return -EEXIST; 8024 8025 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT); 8026 if (IS_ERR(prog)) 8027 return PTR_ERR(prog); 8028 8029 event->prog = prog; 8030 event->orig_overflow_handler = READ_ONCE(event->overflow_handler); 8031 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler); 8032 return 0; 8033 } 8034 8035 static void perf_event_free_bpf_handler(struct perf_event *event) 8036 { 8037 struct bpf_prog *prog = event->prog; 8038 8039 if (!prog) 8040 return; 8041 8042 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler); 8043 event->prog = NULL; 8044 bpf_prog_put(prog); 8045 } 8046 #else 8047 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd) 8048 { 8049 return -EOPNOTSUPP; 8050 } 8051 static void perf_event_free_bpf_handler(struct perf_event *event) 8052 { 8053 } 8054 #endif 8055 8056 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) 8057 { 8058 bool is_kprobe, is_tracepoint; 8059 struct bpf_prog *prog; 8060 8061 if (event->attr.type == PERF_TYPE_HARDWARE || 8062 event->attr.type == PERF_TYPE_SOFTWARE) 8063 return perf_event_set_bpf_handler(event, prog_fd); 8064 8065 if (event->attr.type != PERF_TYPE_TRACEPOINT) 8066 return -EINVAL; 8067 8068 if (event->tp_event->prog) 8069 return -EEXIST; 8070 8071 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE; 8072 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT; 8073 if (!is_kprobe && !is_tracepoint) 8074 /* bpf programs can only be attached to u/kprobe or tracepoint */ 8075 return -EINVAL; 8076 8077 prog = bpf_prog_get(prog_fd); 8078 if (IS_ERR(prog)) 8079 return PTR_ERR(prog); 8080 8081 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) || 8082 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT)) { 8083 /* valid fd, but invalid bpf program type */ 8084 bpf_prog_put(prog); 8085 return -EINVAL; 8086 } 8087 8088 if (is_tracepoint) { 8089 int off = trace_event_get_offsets(event->tp_event); 8090 8091 if (prog->aux->max_ctx_offset > off) { 8092 bpf_prog_put(prog); 8093 return -EACCES; 8094 } 8095 } 8096 event->tp_event->prog = prog; 8097 8098 return 0; 8099 } 8100 8101 static void perf_event_free_bpf_prog(struct perf_event *event) 8102 { 8103 struct bpf_prog *prog; 8104 8105 perf_event_free_bpf_handler(event); 8106 8107 if (!event->tp_event) 8108 return; 8109 8110 prog = event->tp_event->prog; 8111 if (prog) { 8112 event->tp_event->prog = NULL; 8113 bpf_prog_put(prog); 8114 } 8115 } 8116 8117 #else 8118 8119 static inline void perf_tp_register(void) 8120 { 8121 } 8122 8123 static void perf_event_free_filter(struct perf_event *event) 8124 { 8125 } 8126 8127 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) 8128 { 8129 return -ENOENT; 8130 } 8131 8132 static void perf_event_free_bpf_prog(struct perf_event *event) 8133 { 8134 } 8135 #endif /* CONFIG_EVENT_TRACING */ 8136 8137 #ifdef CONFIG_HAVE_HW_BREAKPOINT 8138 void perf_bp_event(struct perf_event *bp, void *data) 8139 { 8140 struct perf_sample_data sample; 8141 struct pt_regs *regs = data; 8142 8143 perf_sample_data_init(&sample, bp->attr.bp_addr, 0); 8144 8145 if (!bp->hw.state && !perf_exclude_event(bp, regs)) 8146 perf_swevent_event(bp, 1, &sample, regs); 8147 } 8148 #endif 8149 8150 /* 8151 * Allocate a new address filter 8152 */ 8153 static struct perf_addr_filter * 8154 perf_addr_filter_new(struct perf_event *event, struct list_head *filters) 8155 { 8156 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu); 8157 struct perf_addr_filter *filter; 8158 8159 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node); 8160 if (!filter) 8161 return NULL; 8162 8163 INIT_LIST_HEAD(&filter->entry); 8164 list_add_tail(&filter->entry, filters); 8165 8166 return filter; 8167 } 8168 8169 static void free_filters_list(struct list_head *filters) 8170 { 8171 struct perf_addr_filter *filter, *iter; 8172 8173 list_for_each_entry_safe(filter, iter, filters, entry) { 8174 if (filter->inode) 8175 iput(filter->inode); 8176 list_del(&filter->entry); 8177 kfree(filter); 8178 } 8179 } 8180 8181 /* 8182 * Free existing address filters and optionally install new ones 8183 */ 8184 static void perf_addr_filters_splice(struct perf_event *event, 8185 struct list_head *head) 8186 { 8187 unsigned long flags; 8188 LIST_HEAD(list); 8189 8190 if (!has_addr_filter(event)) 8191 return; 8192 8193 /* don't bother with children, they don't have their own filters */ 8194 if (event->parent) 8195 return; 8196 8197 raw_spin_lock_irqsave(&event->addr_filters.lock, flags); 8198 8199 list_splice_init(&event->addr_filters.list, &list); 8200 if (head) 8201 list_splice(head, &event->addr_filters.list); 8202 8203 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags); 8204 8205 free_filters_list(&list); 8206 } 8207 8208 /* 8209 * Scan through mm's vmas and see if one of them matches the 8210 * @filter; if so, adjust filter's address range. 8211 * Called with mm::mmap_sem down for reading. 8212 */ 8213 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter, 8214 struct mm_struct *mm) 8215 { 8216 struct vm_area_struct *vma; 8217 8218 for (vma = mm->mmap; vma; vma = vma->vm_next) { 8219 struct file *file = vma->vm_file; 8220 unsigned long off = vma->vm_pgoff << PAGE_SHIFT; 8221 unsigned long vma_size = vma->vm_end - vma->vm_start; 8222 8223 if (!file) 8224 continue; 8225 8226 if (!perf_addr_filter_match(filter, file, off, vma_size)) 8227 continue; 8228 8229 return vma->vm_start; 8230 } 8231 8232 return 0; 8233 } 8234 8235 /* 8236 * Update event's address range filters based on the 8237 * task's existing mappings, if any. 8238 */ 8239 static void perf_event_addr_filters_apply(struct perf_event *event) 8240 { 8241 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 8242 struct task_struct *task = READ_ONCE(event->ctx->task); 8243 struct perf_addr_filter *filter; 8244 struct mm_struct *mm = NULL; 8245 unsigned int count = 0; 8246 unsigned long flags; 8247 8248 /* 8249 * We may observe TASK_TOMBSTONE, which means that the event tear-down 8250 * will stop on the parent's child_mutex that our caller is also holding 8251 */ 8252 if (task == TASK_TOMBSTONE) 8253 return; 8254 8255 if (!ifh->nr_file_filters) 8256 return; 8257 8258 mm = get_task_mm(event->ctx->task); 8259 if (!mm) 8260 goto restart; 8261 8262 down_read(&mm->mmap_sem); 8263 8264 raw_spin_lock_irqsave(&ifh->lock, flags); 8265 list_for_each_entry(filter, &ifh->list, entry) { 8266 event->addr_filters_offs[count] = 0; 8267 8268 /* 8269 * Adjust base offset if the filter is associated to a binary 8270 * that needs to be mapped: 8271 */ 8272 if (filter->inode) 8273 event->addr_filters_offs[count] = 8274 perf_addr_filter_apply(filter, mm); 8275 8276 count++; 8277 } 8278 8279 event->addr_filters_gen++; 8280 raw_spin_unlock_irqrestore(&ifh->lock, flags); 8281 8282 up_read(&mm->mmap_sem); 8283 8284 mmput(mm); 8285 8286 restart: 8287 perf_event_stop(event, 1); 8288 } 8289 8290 /* 8291 * Address range filtering: limiting the data to certain 8292 * instruction address ranges. Filters are ioctl()ed to us from 8293 * userspace as ascii strings. 8294 * 8295 * Filter string format: 8296 * 8297 * ACTION RANGE_SPEC 8298 * where ACTION is one of the 8299 * * "filter": limit the trace to this region 8300 * * "start": start tracing from this address 8301 * * "stop": stop tracing at this address/region; 8302 * RANGE_SPEC is 8303 * * for kernel addresses: <start address>[/<size>] 8304 * * for object files: <start address>[/<size>]@</path/to/object/file> 8305 * 8306 * if <size> is not specified, the range is treated as a single address. 8307 */ 8308 enum { 8309 IF_ACT_NONE = -1, 8310 IF_ACT_FILTER, 8311 IF_ACT_START, 8312 IF_ACT_STOP, 8313 IF_SRC_FILE, 8314 IF_SRC_KERNEL, 8315 IF_SRC_FILEADDR, 8316 IF_SRC_KERNELADDR, 8317 }; 8318 8319 enum { 8320 IF_STATE_ACTION = 0, 8321 IF_STATE_SOURCE, 8322 IF_STATE_END, 8323 }; 8324 8325 static const match_table_t if_tokens = { 8326 { IF_ACT_FILTER, "filter" }, 8327 { IF_ACT_START, "start" }, 8328 { IF_ACT_STOP, "stop" }, 8329 { IF_SRC_FILE, "%u/%u@%s" }, 8330 { IF_SRC_KERNEL, "%u/%u" }, 8331 { IF_SRC_FILEADDR, "%u@%s" }, 8332 { IF_SRC_KERNELADDR, "%u" }, 8333 { IF_ACT_NONE, NULL }, 8334 }; 8335 8336 /* 8337 * Address filter string parser 8338 */ 8339 static int 8340 perf_event_parse_addr_filter(struct perf_event *event, char *fstr, 8341 struct list_head *filters) 8342 { 8343 struct perf_addr_filter *filter = NULL; 8344 char *start, *orig, *filename = NULL; 8345 struct path path; 8346 substring_t args[MAX_OPT_ARGS]; 8347 int state = IF_STATE_ACTION, token; 8348 unsigned int kernel = 0; 8349 int ret = -EINVAL; 8350 8351 orig = fstr = kstrdup(fstr, GFP_KERNEL); 8352 if (!fstr) 8353 return -ENOMEM; 8354 8355 while ((start = strsep(&fstr, " ,\n")) != NULL) { 8356 ret = -EINVAL; 8357 8358 if (!*start) 8359 continue; 8360 8361 /* filter definition begins */ 8362 if (state == IF_STATE_ACTION) { 8363 filter = perf_addr_filter_new(event, filters); 8364 if (!filter) 8365 goto fail; 8366 } 8367 8368 token = match_token(start, if_tokens, args); 8369 switch (token) { 8370 case IF_ACT_FILTER: 8371 case IF_ACT_START: 8372 filter->filter = 1; 8373 8374 case IF_ACT_STOP: 8375 if (state != IF_STATE_ACTION) 8376 goto fail; 8377 8378 state = IF_STATE_SOURCE; 8379 break; 8380 8381 case IF_SRC_KERNELADDR: 8382 case IF_SRC_KERNEL: 8383 kernel = 1; 8384 8385 case IF_SRC_FILEADDR: 8386 case IF_SRC_FILE: 8387 if (state != IF_STATE_SOURCE) 8388 goto fail; 8389 8390 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL) 8391 filter->range = 1; 8392 8393 *args[0].to = 0; 8394 ret = kstrtoul(args[0].from, 0, &filter->offset); 8395 if (ret) 8396 goto fail; 8397 8398 if (filter->range) { 8399 *args[1].to = 0; 8400 ret = kstrtoul(args[1].from, 0, &filter->size); 8401 if (ret) 8402 goto fail; 8403 } 8404 8405 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) { 8406 int fpos = filter->range ? 2 : 1; 8407 8408 filename = match_strdup(&args[fpos]); 8409 if (!filename) { 8410 ret = -ENOMEM; 8411 goto fail; 8412 } 8413 } 8414 8415 state = IF_STATE_END; 8416 break; 8417 8418 default: 8419 goto fail; 8420 } 8421 8422 /* 8423 * Filter definition is fully parsed, validate and install it. 8424 * Make sure that it doesn't contradict itself or the event's 8425 * attribute. 8426 */ 8427 if (state == IF_STATE_END) { 8428 ret = -EINVAL; 8429 if (kernel && event->attr.exclude_kernel) 8430 goto fail; 8431 8432 if (!kernel) { 8433 if (!filename) 8434 goto fail; 8435 8436 /* 8437 * For now, we only support file-based filters 8438 * in per-task events; doing so for CPU-wide 8439 * events requires additional context switching 8440 * trickery, since same object code will be 8441 * mapped at different virtual addresses in 8442 * different processes. 8443 */ 8444 ret = -EOPNOTSUPP; 8445 if (!event->ctx->task) 8446 goto fail_free_name; 8447 8448 /* look up the path and grab its inode */ 8449 ret = kern_path(filename, LOOKUP_FOLLOW, &path); 8450 if (ret) 8451 goto fail_free_name; 8452 8453 filter->inode = igrab(d_inode(path.dentry)); 8454 path_put(&path); 8455 kfree(filename); 8456 filename = NULL; 8457 8458 ret = -EINVAL; 8459 if (!filter->inode || 8460 !S_ISREG(filter->inode->i_mode)) 8461 /* free_filters_list() will iput() */ 8462 goto fail; 8463 8464 event->addr_filters.nr_file_filters++; 8465 } 8466 8467 /* ready to consume more filters */ 8468 state = IF_STATE_ACTION; 8469 filter = NULL; 8470 } 8471 } 8472 8473 if (state != IF_STATE_ACTION) 8474 goto fail; 8475 8476 kfree(orig); 8477 8478 return 0; 8479 8480 fail_free_name: 8481 kfree(filename); 8482 fail: 8483 free_filters_list(filters); 8484 kfree(orig); 8485 8486 return ret; 8487 } 8488 8489 static int 8490 perf_event_set_addr_filter(struct perf_event *event, char *filter_str) 8491 { 8492 LIST_HEAD(filters); 8493 int ret; 8494 8495 /* 8496 * Since this is called in perf_ioctl() path, we're already holding 8497 * ctx::mutex. 8498 */ 8499 lockdep_assert_held(&event->ctx->mutex); 8500 8501 if (WARN_ON_ONCE(event->parent)) 8502 return -EINVAL; 8503 8504 ret = perf_event_parse_addr_filter(event, filter_str, &filters); 8505 if (ret) 8506 goto fail_clear_files; 8507 8508 ret = event->pmu->addr_filters_validate(&filters); 8509 if (ret) 8510 goto fail_free_filters; 8511 8512 /* remove existing filters, if any */ 8513 perf_addr_filters_splice(event, &filters); 8514 8515 /* install new filters */ 8516 perf_event_for_each_child(event, perf_event_addr_filters_apply); 8517 8518 return ret; 8519 8520 fail_free_filters: 8521 free_filters_list(&filters); 8522 8523 fail_clear_files: 8524 event->addr_filters.nr_file_filters = 0; 8525 8526 return ret; 8527 } 8528 8529 static int perf_event_set_filter(struct perf_event *event, void __user *arg) 8530 { 8531 char *filter_str; 8532 int ret = -EINVAL; 8533 8534 if ((event->attr.type != PERF_TYPE_TRACEPOINT || 8535 !IS_ENABLED(CONFIG_EVENT_TRACING)) && 8536 !has_addr_filter(event)) 8537 return -EINVAL; 8538 8539 filter_str = strndup_user(arg, PAGE_SIZE); 8540 if (IS_ERR(filter_str)) 8541 return PTR_ERR(filter_str); 8542 8543 if (IS_ENABLED(CONFIG_EVENT_TRACING) && 8544 event->attr.type == PERF_TYPE_TRACEPOINT) 8545 ret = ftrace_profile_set_filter(event, event->attr.config, 8546 filter_str); 8547 else if (has_addr_filter(event)) 8548 ret = perf_event_set_addr_filter(event, filter_str); 8549 8550 kfree(filter_str); 8551 return ret; 8552 } 8553 8554 /* 8555 * hrtimer based swevent callback 8556 */ 8557 8558 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer) 8559 { 8560 enum hrtimer_restart ret = HRTIMER_RESTART; 8561 struct perf_sample_data data; 8562 struct pt_regs *regs; 8563 struct perf_event *event; 8564 u64 period; 8565 8566 event = container_of(hrtimer, struct perf_event, hw.hrtimer); 8567 8568 if (event->state != PERF_EVENT_STATE_ACTIVE) 8569 return HRTIMER_NORESTART; 8570 8571 event->pmu->read(event); 8572 8573 perf_sample_data_init(&data, 0, event->hw.last_period); 8574 regs = get_irq_regs(); 8575 8576 if (regs && !perf_exclude_event(event, regs)) { 8577 if (!(event->attr.exclude_idle && is_idle_task(current))) 8578 if (__perf_event_overflow(event, 1, &data, regs)) 8579 ret = HRTIMER_NORESTART; 8580 } 8581 8582 period = max_t(u64, 10000, event->hw.sample_period); 8583 hrtimer_forward_now(hrtimer, ns_to_ktime(period)); 8584 8585 return ret; 8586 } 8587 8588 static void perf_swevent_start_hrtimer(struct perf_event *event) 8589 { 8590 struct hw_perf_event *hwc = &event->hw; 8591 s64 period; 8592 8593 if (!is_sampling_event(event)) 8594 return; 8595 8596 period = local64_read(&hwc->period_left); 8597 if (period) { 8598 if (period < 0) 8599 period = 10000; 8600 8601 local64_set(&hwc->period_left, 0); 8602 } else { 8603 period = max_t(u64, 10000, hwc->sample_period); 8604 } 8605 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period), 8606 HRTIMER_MODE_REL_PINNED); 8607 } 8608 8609 static void perf_swevent_cancel_hrtimer(struct perf_event *event) 8610 { 8611 struct hw_perf_event *hwc = &event->hw; 8612 8613 if (is_sampling_event(event)) { 8614 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer); 8615 local64_set(&hwc->period_left, ktime_to_ns(remaining)); 8616 8617 hrtimer_cancel(&hwc->hrtimer); 8618 } 8619 } 8620 8621 static void perf_swevent_init_hrtimer(struct perf_event *event) 8622 { 8623 struct hw_perf_event *hwc = &event->hw; 8624 8625 if (!is_sampling_event(event)) 8626 return; 8627 8628 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 8629 hwc->hrtimer.function = perf_swevent_hrtimer; 8630 8631 /* 8632 * Since hrtimers have a fixed rate, we can do a static freq->period 8633 * mapping and avoid the whole period adjust feedback stuff. 8634 */ 8635 if (event->attr.freq) { 8636 long freq = event->attr.sample_freq; 8637 8638 event->attr.sample_period = NSEC_PER_SEC / freq; 8639 hwc->sample_period = event->attr.sample_period; 8640 local64_set(&hwc->period_left, hwc->sample_period); 8641 hwc->last_period = hwc->sample_period; 8642 event->attr.freq = 0; 8643 } 8644 } 8645 8646 /* 8647 * Software event: cpu wall time clock 8648 */ 8649 8650 static void cpu_clock_event_update(struct perf_event *event) 8651 { 8652 s64 prev; 8653 u64 now; 8654 8655 now = local_clock(); 8656 prev = local64_xchg(&event->hw.prev_count, now); 8657 local64_add(now - prev, &event->count); 8658 } 8659 8660 static void cpu_clock_event_start(struct perf_event *event, int flags) 8661 { 8662 local64_set(&event->hw.prev_count, local_clock()); 8663 perf_swevent_start_hrtimer(event); 8664 } 8665 8666 static void cpu_clock_event_stop(struct perf_event *event, int flags) 8667 { 8668 perf_swevent_cancel_hrtimer(event); 8669 cpu_clock_event_update(event); 8670 } 8671 8672 static int cpu_clock_event_add(struct perf_event *event, int flags) 8673 { 8674 if (flags & PERF_EF_START) 8675 cpu_clock_event_start(event, flags); 8676 perf_event_update_userpage(event); 8677 8678 return 0; 8679 } 8680 8681 static void cpu_clock_event_del(struct perf_event *event, int flags) 8682 { 8683 cpu_clock_event_stop(event, flags); 8684 } 8685 8686 static void cpu_clock_event_read(struct perf_event *event) 8687 { 8688 cpu_clock_event_update(event); 8689 } 8690 8691 static int cpu_clock_event_init(struct perf_event *event) 8692 { 8693 if (event->attr.type != PERF_TYPE_SOFTWARE) 8694 return -ENOENT; 8695 8696 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK) 8697 return -ENOENT; 8698 8699 /* 8700 * no branch sampling for software events 8701 */ 8702 if (has_branch_stack(event)) 8703 return -EOPNOTSUPP; 8704 8705 perf_swevent_init_hrtimer(event); 8706 8707 return 0; 8708 } 8709 8710 static struct pmu perf_cpu_clock = { 8711 .task_ctx_nr = perf_sw_context, 8712 8713 .capabilities = PERF_PMU_CAP_NO_NMI, 8714 8715 .event_init = cpu_clock_event_init, 8716 .add = cpu_clock_event_add, 8717 .del = cpu_clock_event_del, 8718 .start = cpu_clock_event_start, 8719 .stop = cpu_clock_event_stop, 8720 .read = cpu_clock_event_read, 8721 }; 8722 8723 /* 8724 * Software event: task time clock 8725 */ 8726 8727 static void task_clock_event_update(struct perf_event *event, u64 now) 8728 { 8729 u64 prev; 8730 s64 delta; 8731 8732 prev = local64_xchg(&event->hw.prev_count, now); 8733 delta = now - prev; 8734 local64_add(delta, &event->count); 8735 } 8736 8737 static void task_clock_event_start(struct perf_event *event, int flags) 8738 { 8739 local64_set(&event->hw.prev_count, event->ctx->time); 8740 perf_swevent_start_hrtimer(event); 8741 } 8742 8743 static void task_clock_event_stop(struct perf_event *event, int flags) 8744 { 8745 perf_swevent_cancel_hrtimer(event); 8746 task_clock_event_update(event, event->ctx->time); 8747 } 8748 8749 static int task_clock_event_add(struct perf_event *event, int flags) 8750 { 8751 if (flags & PERF_EF_START) 8752 task_clock_event_start(event, flags); 8753 perf_event_update_userpage(event); 8754 8755 return 0; 8756 } 8757 8758 static void task_clock_event_del(struct perf_event *event, int flags) 8759 { 8760 task_clock_event_stop(event, PERF_EF_UPDATE); 8761 } 8762 8763 static void task_clock_event_read(struct perf_event *event) 8764 { 8765 u64 now = perf_clock(); 8766 u64 delta = now - event->ctx->timestamp; 8767 u64 time = event->ctx->time + delta; 8768 8769 task_clock_event_update(event, time); 8770 } 8771 8772 static int task_clock_event_init(struct perf_event *event) 8773 { 8774 if (event->attr.type != PERF_TYPE_SOFTWARE) 8775 return -ENOENT; 8776 8777 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK) 8778 return -ENOENT; 8779 8780 /* 8781 * no branch sampling for software events 8782 */ 8783 if (has_branch_stack(event)) 8784 return -EOPNOTSUPP; 8785 8786 perf_swevent_init_hrtimer(event); 8787 8788 return 0; 8789 } 8790 8791 static struct pmu perf_task_clock = { 8792 .task_ctx_nr = perf_sw_context, 8793 8794 .capabilities = PERF_PMU_CAP_NO_NMI, 8795 8796 .event_init = task_clock_event_init, 8797 .add = task_clock_event_add, 8798 .del = task_clock_event_del, 8799 .start = task_clock_event_start, 8800 .stop = task_clock_event_stop, 8801 .read = task_clock_event_read, 8802 }; 8803 8804 static void perf_pmu_nop_void(struct pmu *pmu) 8805 { 8806 } 8807 8808 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags) 8809 { 8810 } 8811 8812 static int perf_pmu_nop_int(struct pmu *pmu) 8813 { 8814 return 0; 8815 } 8816 8817 static DEFINE_PER_CPU(unsigned int, nop_txn_flags); 8818 8819 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags) 8820 { 8821 __this_cpu_write(nop_txn_flags, flags); 8822 8823 if (flags & ~PERF_PMU_TXN_ADD) 8824 return; 8825 8826 perf_pmu_disable(pmu); 8827 } 8828 8829 static int perf_pmu_commit_txn(struct pmu *pmu) 8830 { 8831 unsigned int flags = __this_cpu_read(nop_txn_flags); 8832 8833 __this_cpu_write(nop_txn_flags, 0); 8834 8835 if (flags & ~PERF_PMU_TXN_ADD) 8836 return 0; 8837 8838 perf_pmu_enable(pmu); 8839 return 0; 8840 } 8841 8842 static void perf_pmu_cancel_txn(struct pmu *pmu) 8843 { 8844 unsigned int flags = __this_cpu_read(nop_txn_flags); 8845 8846 __this_cpu_write(nop_txn_flags, 0); 8847 8848 if (flags & ~PERF_PMU_TXN_ADD) 8849 return; 8850 8851 perf_pmu_enable(pmu); 8852 } 8853 8854 static int perf_event_idx_default(struct perf_event *event) 8855 { 8856 return 0; 8857 } 8858 8859 /* 8860 * Ensures all contexts with the same task_ctx_nr have the same 8861 * pmu_cpu_context too. 8862 */ 8863 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn) 8864 { 8865 struct pmu *pmu; 8866 8867 if (ctxn < 0) 8868 return NULL; 8869 8870 list_for_each_entry(pmu, &pmus, entry) { 8871 if (pmu->task_ctx_nr == ctxn) 8872 return pmu->pmu_cpu_context; 8873 } 8874 8875 return NULL; 8876 } 8877 8878 static void free_pmu_context(struct pmu *pmu) 8879 { 8880 mutex_lock(&pmus_lock); 8881 free_percpu(pmu->pmu_cpu_context); 8882 mutex_unlock(&pmus_lock); 8883 } 8884 8885 /* 8886 * Let userspace know that this PMU supports address range filtering: 8887 */ 8888 static ssize_t nr_addr_filters_show(struct device *dev, 8889 struct device_attribute *attr, 8890 char *page) 8891 { 8892 struct pmu *pmu = dev_get_drvdata(dev); 8893 8894 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters); 8895 } 8896 DEVICE_ATTR_RO(nr_addr_filters); 8897 8898 static struct idr pmu_idr; 8899 8900 static ssize_t 8901 type_show(struct device *dev, struct device_attribute *attr, char *page) 8902 { 8903 struct pmu *pmu = dev_get_drvdata(dev); 8904 8905 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type); 8906 } 8907 static DEVICE_ATTR_RO(type); 8908 8909 static ssize_t 8910 perf_event_mux_interval_ms_show(struct device *dev, 8911 struct device_attribute *attr, 8912 char *page) 8913 { 8914 struct pmu *pmu = dev_get_drvdata(dev); 8915 8916 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms); 8917 } 8918 8919 static DEFINE_MUTEX(mux_interval_mutex); 8920 8921 static ssize_t 8922 perf_event_mux_interval_ms_store(struct device *dev, 8923 struct device_attribute *attr, 8924 const char *buf, size_t count) 8925 { 8926 struct pmu *pmu = dev_get_drvdata(dev); 8927 int timer, cpu, ret; 8928 8929 ret = kstrtoint(buf, 0, &timer); 8930 if (ret) 8931 return ret; 8932 8933 if (timer < 1) 8934 return -EINVAL; 8935 8936 /* same value, noting to do */ 8937 if (timer == pmu->hrtimer_interval_ms) 8938 return count; 8939 8940 mutex_lock(&mux_interval_mutex); 8941 pmu->hrtimer_interval_ms = timer; 8942 8943 /* update all cpuctx for this PMU */ 8944 get_online_cpus(); 8945 for_each_online_cpu(cpu) { 8946 struct perf_cpu_context *cpuctx; 8947 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 8948 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer); 8949 8950 cpu_function_call(cpu, 8951 (remote_function_f)perf_mux_hrtimer_restart, cpuctx); 8952 } 8953 put_online_cpus(); 8954 mutex_unlock(&mux_interval_mutex); 8955 8956 return count; 8957 } 8958 static DEVICE_ATTR_RW(perf_event_mux_interval_ms); 8959 8960 static struct attribute *pmu_dev_attrs[] = { 8961 &dev_attr_type.attr, 8962 &dev_attr_perf_event_mux_interval_ms.attr, 8963 NULL, 8964 }; 8965 ATTRIBUTE_GROUPS(pmu_dev); 8966 8967 static int pmu_bus_running; 8968 static struct bus_type pmu_bus = { 8969 .name = "event_source", 8970 .dev_groups = pmu_dev_groups, 8971 }; 8972 8973 static void pmu_dev_release(struct device *dev) 8974 { 8975 kfree(dev); 8976 } 8977 8978 static int pmu_dev_alloc(struct pmu *pmu) 8979 { 8980 int ret = -ENOMEM; 8981 8982 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL); 8983 if (!pmu->dev) 8984 goto out; 8985 8986 pmu->dev->groups = pmu->attr_groups; 8987 device_initialize(pmu->dev); 8988 ret = dev_set_name(pmu->dev, "%s", pmu->name); 8989 if (ret) 8990 goto free_dev; 8991 8992 dev_set_drvdata(pmu->dev, pmu); 8993 pmu->dev->bus = &pmu_bus; 8994 pmu->dev->release = pmu_dev_release; 8995 ret = device_add(pmu->dev); 8996 if (ret) 8997 goto free_dev; 8998 8999 /* For PMUs with address filters, throw in an extra attribute: */ 9000 if (pmu->nr_addr_filters) 9001 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters); 9002 9003 if (ret) 9004 goto del_dev; 9005 9006 out: 9007 return ret; 9008 9009 del_dev: 9010 device_del(pmu->dev); 9011 9012 free_dev: 9013 put_device(pmu->dev); 9014 goto out; 9015 } 9016 9017 static struct lock_class_key cpuctx_mutex; 9018 static struct lock_class_key cpuctx_lock; 9019 9020 int perf_pmu_register(struct pmu *pmu, const char *name, int type) 9021 { 9022 int cpu, ret; 9023 9024 mutex_lock(&pmus_lock); 9025 ret = -ENOMEM; 9026 pmu->pmu_disable_count = alloc_percpu(int); 9027 if (!pmu->pmu_disable_count) 9028 goto unlock; 9029 9030 pmu->type = -1; 9031 if (!name) 9032 goto skip_type; 9033 pmu->name = name; 9034 9035 if (type < 0) { 9036 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL); 9037 if (type < 0) { 9038 ret = type; 9039 goto free_pdc; 9040 } 9041 } 9042 pmu->type = type; 9043 9044 if (pmu_bus_running) { 9045 ret = pmu_dev_alloc(pmu); 9046 if (ret) 9047 goto free_idr; 9048 } 9049 9050 skip_type: 9051 if (pmu->task_ctx_nr == perf_hw_context) { 9052 static int hw_context_taken = 0; 9053 9054 /* 9055 * Other than systems with heterogeneous CPUs, it never makes 9056 * sense for two PMUs to share perf_hw_context. PMUs which are 9057 * uncore must use perf_invalid_context. 9058 */ 9059 if (WARN_ON_ONCE(hw_context_taken && 9060 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS))) 9061 pmu->task_ctx_nr = perf_invalid_context; 9062 9063 hw_context_taken = 1; 9064 } 9065 9066 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr); 9067 if (pmu->pmu_cpu_context) 9068 goto got_cpu_context; 9069 9070 ret = -ENOMEM; 9071 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context); 9072 if (!pmu->pmu_cpu_context) 9073 goto free_dev; 9074 9075 for_each_possible_cpu(cpu) { 9076 struct perf_cpu_context *cpuctx; 9077 9078 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 9079 __perf_event_init_context(&cpuctx->ctx); 9080 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex); 9081 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock); 9082 cpuctx->ctx.pmu = pmu; 9083 9084 __perf_mux_hrtimer_init(cpuctx, cpu); 9085 } 9086 9087 got_cpu_context: 9088 if (!pmu->start_txn) { 9089 if (pmu->pmu_enable) { 9090 /* 9091 * If we have pmu_enable/pmu_disable calls, install 9092 * transaction stubs that use that to try and batch 9093 * hardware accesses. 9094 */ 9095 pmu->start_txn = perf_pmu_start_txn; 9096 pmu->commit_txn = perf_pmu_commit_txn; 9097 pmu->cancel_txn = perf_pmu_cancel_txn; 9098 } else { 9099 pmu->start_txn = perf_pmu_nop_txn; 9100 pmu->commit_txn = perf_pmu_nop_int; 9101 pmu->cancel_txn = perf_pmu_nop_void; 9102 } 9103 } 9104 9105 if (!pmu->pmu_enable) { 9106 pmu->pmu_enable = perf_pmu_nop_void; 9107 pmu->pmu_disable = perf_pmu_nop_void; 9108 } 9109 9110 if (!pmu->event_idx) 9111 pmu->event_idx = perf_event_idx_default; 9112 9113 list_add_rcu(&pmu->entry, &pmus); 9114 atomic_set(&pmu->exclusive_cnt, 0); 9115 ret = 0; 9116 unlock: 9117 mutex_unlock(&pmus_lock); 9118 9119 return ret; 9120 9121 free_dev: 9122 device_del(pmu->dev); 9123 put_device(pmu->dev); 9124 9125 free_idr: 9126 if (pmu->type >= PERF_TYPE_MAX) 9127 idr_remove(&pmu_idr, pmu->type); 9128 9129 free_pdc: 9130 free_percpu(pmu->pmu_disable_count); 9131 goto unlock; 9132 } 9133 EXPORT_SYMBOL_GPL(perf_pmu_register); 9134 9135 void perf_pmu_unregister(struct pmu *pmu) 9136 { 9137 int remove_device; 9138 9139 mutex_lock(&pmus_lock); 9140 remove_device = pmu_bus_running; 9141 list_del_rcu(&pmu->entry); 9142 mutex_unlock(&pmus_lock); 9143 9144 /* 9145 * We dereference the pmu list under both SRCU and regular RCU, so 9146 * synchronize against both of those. 9147 */ 9148 synchronize_srcu(&pmus_srcu); 9149 synchronize_rcu(); 9150 9151 free_percpu(pmu->pmu_disable_count); 9152 if (pmu->type >= PERF_TYPE_MAX) 9153 idr_remove(&pmu_idr, pmu->type); 9154 if (remove_device) { 9155 if (pmu->nr_addr_filters) 9156 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters); 9157 device_del(pmu->dev); 9158 put_device(pmu->dev); 9159 } 9160 free_pmu_context(pmu); 9161 } 9162 EXPORT_SYMBOL_GPL(perf_pmu_unregister); 9163 9164 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event) 9165 { 9166 struct perf_event_context *ctx = NULL; 9167 int ret; 9168 9169 if (!try_module_get(pmu->module)) 9170 return -ENODEV; 9171 9172 if (event->group_leader != event) { 9173 /* 9174 * This ctx->mutex can nest when we're called through 9175 * inheritance. See the perf_event_ctx_lock_nested() comment. 9176 */ 9177 ctx = perf_event_ctx_lock_nested(event->group_leader, 9178 SINGLE_DEPTH_NESTING); 9179 BUG_ON(!ctx); 9180 } 9181 9182 event->pmu = pmu; 9183 ret = pmu->event_init(event); 9184 9185 if (ctx) 9186 perf_event_ctx_unlock(event->group_leader, ctx); 9187 9188 if (ret) 9189 module_put(pmu->module); 9190 9191 return ret; 9192 } 9193 9194 static struct pmu *perf_init_event(struct perf_event *event) 9195 { 9196 struct pmu *pmu = NULL; 9197 int idx; 9198 int ret; 9199 9200 idx = srcu_read_lock(&pmus_srcu); 9201 9202 /* Try parent's PMU first: */ 9203 if (event->parent && event->parent->pmu) { 9204 pmu = event->parent->pmu; 9205 ret = perf_try_init_event(pmu, event); 9206 if (!ret) 9207 goto unlock; 9208 } 9209 9210 rcu_read_lock(); 9211 pmu = idr_find(&pmu_idr, event->attr.type); 9212 rcu_read_unlock(); 9213 if (pmu) { 9214 ret = perf_try_init_event(pmu, event); 9215 if (ret) 9216 pmu = ERR_PTR(ret); 9217 goto unlock; 9218 } 9219 9220 list_for_each_entry_rcu(pmu, &pmus, entry) { 9221 ret = perf_try_init_event(pmu, event); 9222 if (!ret) 9223 goto unlock; 9224 9225 if (ret != -ENOENT) { 9226 pmu = ERR_PTR(ret); 9227 goto unlock; 9228 } 9229 } 9230 pmu = ERR_PTR(-ENOENT); 9231 unlock: 9232 srcu_read_unlock(&pmus_srcu, idx); 9233 9234 return pmu; 9235 } 9236 9237 static void attach_sb_event(struct perf_event *event) 9238 { 9239 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu); 9240 9241 raw_spin_lock(&pel->lock); 9242 list_add_rcu(&event->sb_list, &pel->list); 9243 raw_spin_unlock(&pel->lock); 9244 } 9245 9246 /* 9247 * We keep a list of all !task (and therefore per-cpu) events 9248 * that need to receive side-band records. 9249 * 9250 * This avoids having to scan all the various PMU per-cpu contexts 9251 * looking for them. 9252 */ 9253 static void account_pmu_sb_event(struct perf_event *event) 9254 { 9255 if (is_sb_event(event)) 9256 attach_sb_event(event); 9257 } 9258 9259 static void account_event_cpu(struct perf_event *event, int cpu) 9260 { 9261 if (event->parent) 9262 return; 9263 9264 if (is_cgroup_event(event)) 9265 atomic_inc(&per_cpu(perf_cgroup_events, cpu)); 9266 } 9267 9268 /* Freq events need the tick to stay alive (see perf_event_task_tick). */ 9269 static void account_freq_event_nohz(void) 9270 { 9271 #ifdef CONFIG_NO_HZ_FULL 9272 /* Lock so we don't race with concurrent unaccount */ 9273 spin_lock(&nr_freq_lock); 9274 if (atomic_inc_return(&nr_freq_events) == 1) 9275 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS); 9276 spin_unlock(&nr_freq_lock); 9277 #endif 9278 } 9279 9280 static void account_freq_event(void) 9281 { 9282 if (tick_nohz_full_enabled()) 9283 account_freq_event_nohz(); 9284 else 9285 atomic_inc(&nr_freq_events); 9286 } 9287 9288 9289 static void account_event(struct perf_event *event) 9290 { 9291 bool inc = false; 9292 9293 if (event->parent) 9294 return; 9295 9296 if (event->attach_state & PERF_ATTACH_TASK) 9297 inc = true; 9298 if (event->attr.mmap || event->attr.mmap_data) 9299 atomic_inc(&nr_mmap_events); 9300 if (event->attr.comm) 9301 atomic_inc(&nr_comm_events); 9302 if (event->attr.namespaces) 9303 atomic_inc(&nr_namespaces_events); 9304 if (event->attr.task) 9305 atomic_inc(&nr_task_events); 9306 if (event->attr.freq) 9307 account_freq_event(); 9308 if (event->attr.context_switch) { 9309 atomic_inc(&nr_switch_events); 9310 inc = true; 9311 } 9312 if (has_branch_stack(event)) 9313 inc = true; 9314 if (is_cgroup_event(event)) 9315 inc = true; 9316 9317 if (inc) { 9318 if (atomic_inc_not_zero(&perf_sched_count)) 9319 goto enabled; 9320 9321 mutex_lock(&perf_sched_mutex); 9322 if (!atomic_read(&perf_sched_count)) { 9323 static_branch_enable(&perf_sched_events); 9324 /* 9325 * Guarantee that all CPUs observe they key change and 9326 * call the perf scheduling hooks before proceeding to 9327 * install events that need them. 9328 */ 9329 synchronize_sched(); 9330 } 9331 /* 9332 * Now that we have waited for the sync_sched(), allow further 9333 * increments to by-pass the mutex. 9334 */ 9335 atomic_inc(&perf_sched_count); 9336 mutex_unlock(&perf_sched_mutex); 9337 } 9338 enabled: 9339 9340 account_event_cpu(event, event->cpu); 9341 9342 account_pmu_sb_event(event); 9343 } 9344 9345 /* 9346 * Allocate and initialize a event structure 9347 */ 9348 static struct perf_event * 9349 perf_event_alloc(struct perf_event_attr *attr, int cpu, 9350 struct task_struct *task, 9351 struct perf_event *group_leader, 9352 struct perf_event *parent_event, 9353 perf_overflow_handler_t overflow_handler, 9354 void *context, int cgroup_fd) 9355 { 9356 struct pmu *pmu; 9357 struct perf_event *event; 9358 struct hw_perf_event *hwc; 9359 long err = -EINVAL; 9360 9361 if ((unsigned)cpu >= nr_cpu_ids) { 9362 if (!task || cpu != -1) 9363 return ERR_PTR(-EINVAL); 9364 } 9365 9366 event = kzalloc(sizeof(*event), GFP_KERNEL); 9367 if (!event) 9368 return ERR_PTR(-ENOMEM); 9369 9370 /* 9371 * Single events are their own group leaders, with an 9372 * empty sibling list: 9373 */ 9374 if (!group_leader) 9375 group_leader = event; 9376 9377 mutex_init(&event->child_mutex); 9378 INIT_LIST_HEAD(&event->child_list); 9379 9380 INIT_LIST_HEAD(&event->group_entry); 9381 INIT_LIST_HEAD(&event->event_entry); 9382 INIT_LIST_HEAD(&event->sibling_list); 9383 INIT_LIST_HEAD(&event->rb_entry); 9384 INIT_LIST_HEAD(&event->active_entry); 9385 INIT_LIST_HEAD(&event->addr_filters.list); 9386 INIT_HLIST_NODE(&event->hlist_entry); 9387 9388 9389 init_waitqueue_head(&event->waitq); 9390 init_irq_work(&event->pending, perf_pending_event); 9391 9392 mutex_init(&event->mmap_mutex); 9393 raw_spin_lock_init(&event->addr_filters.lock); 9394 9395 atomic_long_set(&event->refcount, 1); 9396 event->cpu = cpu; 9397 event->attr = *attr; 9398 event->group_leader = group_leader; 9399 event->pmu = NULL; 9400 event->oncpu = -1; 9401 9402 event->parent = parent_event; 9403 9404 event->ns = get_pid_ns(task_active_pid_ns(current)); 9405 event->id = atomic64_inc_return(&perf_event_id); 9406 9407 event->state = PERF_EVENT_STATE_INACTIVE; 9408 9409 if (task) { 9410 event->attach_state = PERF_ATTACH_TASK; 9411 /* 9412 * XXX pmu::event_init needs to know what task to account to 9413 * and we cannot use the ctx information because we need the 9414 * pmu before we get a ctx. 9415 */ 9416 event->hw.target = task; 9417 } 9418 9419 event->clock = &local_clock; 9420 if (parent_event) 9421 event->clock = parent_event->clock; 9422 9423 if (!overflow_handler && parent_event) { 9424 overflow_handler = parent_event->overflow_handler; 9425 context = parent_event->overflow_handler_context; 9426 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING) 9427 if (overflow_handler == bpf_overflow_handler) { 9428 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog); 9429 9430 if (IS_ERR(prog)) { 9431 err = PTR_ERR(prog); 9432 goto err_ns; 9433 } 9434 event->prog = prog; 9435 event->orig_overflow_handler = 9436 parent_event->orig_overflow_handler; 9437 } 9438 #endif 9439 } 9440 9441 if (overflow_handler) { 9442 event->overflow_handler = overflow_handler; 9443 event->overflow_handler_context = context; 9444 } else if (is_write_backward(event)){ 9445 event->overflow_handler = perf_event_output_backward; 9446 event->overflow_handler_context = NULL; 9447 } else { 9448 event->overflow_handler = perf_event_output_forward; 9449 event->overflow_handler_context = NULL; 9450 } 9451 9452 perf_event__state_init(event); 9453 9454 pmu = NULL; 9455 9456 hwc = &event->hw; 9457 hwc->sample_period = attr->sample_period; 9458 if (attr->freq && attr->sample_freq) 9459 hwc->sample_period = 1; 9460 hwc->last_period = hwc->sample_period; 9461 9462 local64_set(&hwc->period_left, hwc->sample_period); 9463 9464 /* 9465 * we currently do not support PERF_FORMAT_GROUP on inherited events 9466 */ 9467 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP)) 9468 goto err_ns; 9469 9470 if (!has_branch_stack(event)) 9471 event->attr.branch_sample_type = 0; 9472 9473 if (cgroup_fd != -1) { 9474 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader); 9475 if (err) 9476 goto err_ns; 9477 } 9478 9479 pmu = perf_init_event(event); 9480 if (!pmu) 9481 goto err_ns; 9482 else if (IS_ERR(pmu)) { 9483 err = PTR_ERR(pmu); 9484 goto err_ns; 9485 } 9486 9487 err = exclusive_event_init(event); 9488 if (err) 9489 goto err_pmu; 9490 9491 if (has_addr_filter(event)) { 9492 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters, 9493 sizeof(unsigned long), 9494 GFP_KERNEL); 9495 if (!event->addr_filters_offs) 9496 goto err_per_task; 9497 9498 /* force hw sync on the address filters */ 9499 event->addr_filters_gen = 1; 9500 } 9501 9502 if (!event->parent) { 9503 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) { 9504 err = get_callchain_buffers(attr->sample_max_stack); 9505 if (err) 9506 goto err_addr_filters; 9507 } 9508 } 9509 9510 /* symmetric to unaccount_event() in _free_event() */ 9511 account_event(event); 9512 9513 return event; 9514 9515 err_addr_filters: 9516 kfree(event->addr_filters_offs); 9517 9518 err_per_task: 9519 exclusive_event_destroy(event); 9520 9521 err_pmu: 9522 if (event->destroy) 9523 event->destroy(event); 9524 module_put(pmu->module); 9525 err_ns: 9526 if (is_cgroup_event(event)) 9527 perf_detach_cgroup(event); 9528 if (event->ns) 9529 put_pid_ns(event->ns); 9530 kfree(event); 9531 9532 return ERR_PTR(err); 9533 } 9534 9535 static int perf_copy_attr(struct perf_event_attr __user *uattr, 9536 struct perf_event_attr *attr) 9537 { 9538 u32 size; 9539 int ret; 9540 9541 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0)) 9542 return -EFAULT; 9543 9544 /* 9545 * zero the full structure, so that a short copy will be nice. 9546 */ 9547 memset(attr, 0, sizeof(*attr)); 9548 9549 ret = get_user(size, &uattr->size); 9550 if (ret) 9551 return ret; 9552 9553 if (size > PAGE_SIZE) /* silly large */ 9554 goto err_size; 9555 9556 if (!size) /* abi compat */ 9557 size = PERF_ATTR_SIZE_VER0; 9558 9559 if (size < PERF_ATTR_SIZE_VER0) 9560 goto err_size; 9561 9562 /* 9563 * If we're handed a bigger struct than we know of, 9564 * ensure all the unknown bits are 0 - i.e. new 9565 * user-space does not rely on any kernel feature 9566 * extensions we dont know about yet. 9567 */ 9568 if (size > sizeof(*attr)) { 9569 unsigned char __user *addr; 9570 unsigned char __user *end; 9571 unsigned char val; 9572 9573 addr = (void __user *)uattr + sizeof(*attr); 9574 end = (void __user *)uattr + size; 9575 9576 for (; addr < end; addr++) { 9577 ret = get_user(val, addr); 9578 if (ret) 9579 return ret; 9580 if (val) 9581 goto err_size; 9582 } 9583 size = sizeof(*attr); 9584 } 9585 9586 ret = copy_from_user(attr, uattr, size); 9587 if (ret) 9588 return -EFAULT; 9589 9590 if (attr->__reserved_1) 9591 return -EINVAL; 9592 9593 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1)) 9594 return -EINVAL; 9595 9596 if (attr->read_format & ~(PERF_FORMAT_MAX-1)) 9597 return -EINVAL; 9598 9599 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) { 9600 u64 mask = attr->branch_sample_type; 9601 9602 /* only using defined bits */ 9603 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1)) 9604 return -EINVAL; 9605 9606 /* at least one branch bit must be set */ 9607 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL)) 9608 return -EINVAL; 9609 9610 /* propagate priv level, when not set for branch */ 9611 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) { 9612 9613 /* exclude_kernel checked on syscall entry */ 9614 if (!attr->exclude_kernel) 9615 mask |= PERF_SAMPLE_BRANCH_KERNEL; 9616 9617 if (!attr->exclude_user) 9618 mask |= PERF_SAMPLE_BRANCH_USER; 9619 9620 if (!attr->exclude_hv) 9621 mask |= PERF_SAMPLE_BRANCH_HV; 9622 /* 9623 * adjust user setting (for HW filter setup) 9624 */ 9625 attr->branch_sample_type = mask; 9626 } 9627 /* privileged levels capture (kernel, hv): check permissions */ 9628 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM) 9629 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) 9630 return -EACCES; 9631 } 9632 9633 if (attr->sample_type & PERF_SAMPLE_REGS_USER) { 9634 ret = perf_reg_validate(attr->sample_regs_user); 9635 if (ret) 9636 return ret; 9637 } 9638 9639 if (attr->sample_type & PERF_SAMPLE_STACK_USER) { 9640 if (!arch_perf_have_user_stack_dump()) 9641 return -ENOSYS; 9642 9643 /* 9644 * We have __u32 type for the size, but so far 9645 * we can only use __u16 as maximum due to the 9646 * __u16 sample size limit. 9647 */ 9648 if (attr->sample_stack_user >= USHRT_MAX) 9649 ret = -EINVAL; 9650 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64))) 9651 ret = -EINVAL; 9652 } 9653 9654 if (attr->sample_type & PERF_SAMPLE_REGS_INTR) 9655 ret = perf_reg_validate(attr->sample_regs_intr); 9656 out: 9657 return ret; 9658 9659 err_size: 9660 put_user(sizeof(*attr), &uattr->size); 9661 ret = -E2BIG; 9662 goto out; 9663 } 9664 9665 static int 9666 perf_event_set_output(struct perf_event *event, struct perf_event *output_event) 9667 { 9668 struct ring_buffer *rb = NULL; 9669 int ret = -EINVAL; 9670 9671 if (!output_event) 9672 goto set; 9673 9674 /* don't allow circular references */ 9675 if (event == output_event) 9676 goto out; 9677 9678 /* 9679 * Don't allow cross-cpu buffers 9680 */ 9681 if (output_event->cpu != event->cpu) 9682 goto out; 9683 9684 /* 9685 * If its not a per-cpu rb, it must be the same task. 9686 */ 9687 if (output_event->cpu == -1 && output_event->ctx != event->ctx) 9688 goto out; 9689 9690 /* 9691 * Mixing clocks in the same buffer is trouble you don't need. 9692 */ 9693 if (output_event->clock != event->clock) 9694 goto out; 9695 9696 /* 9697 * Either writing ring buffer from beginning or from end. 9698 * Mixing is not allowed. 9699 */ 9700 if (is_write_backward(output_event) != is_write_backward(event)) 9701 goto out; 9702 9703 /* 9704 * If both events generate aux data, they must be on the same PMU 9705 */ 9706 if (has_aux(event) && has_aux(output_event) && 9707 event->pmu != output_event->pmu) 9708 goto out; 9709 9710 set: 9711 mutex_lock(&event->mmap_mutex); 9712 /* Can't redirect output if we've got an active mmap() */ 9713 if (atomic_read(&event->mmap_count)) 9714 goto unlock; 9715 9716 if (output_event) { 9717 /* get the rb we want to redirect to */ 9718 rb = ring_buffer_get(output_event); 9719 if (!rb) 9720 goto unlock; 9721 } 9722 9723 ring_buffer_attach(event, rb); 9724 9725 ret = 0; 9726 unlock: 9727 mutex_unlock(&event->mmap_mutex); 9728 9729 out: 9730 return ret; 9731 } 9732 9733 static void mutex_lock_double(struct mutex *a, struct mutex *b) 9734 { 9735 if (b < a) 9736 swap(a, b); 9737 9738 mutex_lock(a); 9739 mutex_lock_nested(b, SINGLE_DEPTH_NESTING); 9740 } 9741 9742 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id) 9743 { 9744 bool nmi_safe = false; 9745 9746 switch (clk_id) { 9747 case CLOCK_MONOTONIC: 9748 event->clock = &ktime_get_mono_fast_ns; 9749 nmi_safe = true; 9750 break; 9751 9752 case CLOCK_MONOTONIC_RAW: 9753 event->clock = &ktime_get_raw_fast_ns; 9754 nmi_safe = true; 9755 break; 9756 9757 case CLOCK_REALTIME: 9758 event->clock = &ktime_get_real_ns; 9759 break; 9760 9761 case CLOCK_BOOTTIME: 9762 event->clock = &ktime_get_boot_ns; 9763 break; 9764 9765 case CLOCK_TAI: 9766 event->clock = &ktime_get_tai_ns; 9767 break; 9768 9769 default: 9770 return -EINVAL; 9771 } 9772 9773 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI)) 9774 return -EINVAL; 9775 9776 return 0; 9777 } 9778 9779 /* 9780 * Variation on perf_event_ctx_lock_nested(), except we take two context 9781 * mutexes. 9782 */ 9783 static struct perf_event_context * 9784 __perf_event_ctx_lock_double(struct perf_event *group_leader, 9785 struct perf_event_context *ctx) 9786 { 9787 struct perf_event_context *gctx; 9788 9789 again: 9790 rcu_read_lock(); 9791 gctx = READ_ONCE(group_leader->ctx); 9792 if (!atomic_inc_not_zero(&gctx->refcount)) { 9793 rcu_read_unlock(); 9794 goto again; 9795 } 9796 rcu_read_unlock(); 9797 9798 mutex_lock_double(&gctx->mutex, &ctx->mutex); 9799 9800 if (group_leader->ctx != gctx) { 9801 mutex_unlock(&ctx->mutex); 9802 mutex_unlock(&gctx->mutex); 9803 put_ctx(gctx); 9804 goto again; 9805 } 9806 9807 return gctx; 9808 } 9809 9810 /** 9811 * sys_perf_event_open - open a performance event, associate it to a task/cpu 9812 * 9813 * @attr_uptr: event_id type attributes for monitoring/sampling 9814 * @pid: target pid 9815 * @cpu: target cpu 9816 * @group_fd: group leader event fd 9817 */ 9818 SYSCALL_DEFINE5(perf_event_open, 9819 struct perf_event_attr __user *, attr_uptr, 9820 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags) 9821 { 9822 struct perf_event *group_leader = NULL, *output_event = NULL; 9823 struct perf_event *event, *sibling; 9824 struct perf_event_attr attr; 9825 struct perf_event_context *ctx, *uninitialized_var(gctx); 9826 struct file *event_file = NULL; 9827 struct fd group = {NULL, 0}; 9828 struct task_struct *task = NULL; 9829 struct pmu *pmu; 9830 int event_fd; 9831 int move_group = 0; 9832 int err; 9833 int f_flags = O_RDWR; 9834 int cgroup_fd = -1; 9835 9836 /* for future expandability... */ 9837 if (flags & ~PERF_FLAG_ALL) 9838 return -EINVAL; 9839 9840 err = perf_copy_attr(attr_uptr, &attr); 9841 if (err) 9842 return err; 9843 9844 if (!attr.exclude_kernel) { 9845 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) 9846 return -EACCES; 9847 } 9848 9849 if (attr.namespaces) { 9850 if (!capable(CAP_SYS_ADMIN)) 9851 return -EACCES; 9852 } 9853 9854 if (attr.freq) { 9855 if (attr.sample_freq > sysctl_perf_event_sample_rate) 9856 return -EINVAL; 9857 } else { 9858 if (attr.sample_period & (1ULL << 63)) 9859 return -EINVAL; 9860 } 9861 9862 if (!attr.sample_max_stack) 9863 attr.sample_max_stack = sysctl_perf_event_max_stack; 9864 9865 /* 9866 * In cgroup mode, the pid argument is used to pass the fd 9867 * opened to the cgroup directory in cgroupfs. The cpu argument 9868 * designates the cpu on which to monitor threads from that 9869 * cgroup. 9870 */ 9871 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1)) 9872 return -EINVAL; 9873 9874 if (flags & PERF_FLAG_FD_CLOEXEC) 9875 f_flags |= O_CLOEXEC; 9876 9877 event_fd = get_unused_fd_flags(f_flags); 9878 if (event_fd < 0) 9879 return event_fd; 9880 9881 if (group_fd != -1) { 9882 err = perf_fget_light(group_fd, &group); 9883 if (err) 9884 goto err_fd; 9885 group_leader = group.file->private_data; 9886 if (flags & PERF_FLAG_FD_OUTPUT) 9887 output_event = group_leader; 9888 if (flags & PERF_FLAG_FD_NO_GROUP) 9889 group_leader = NULL; 9890 } 9891 9892 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) { 9893 task = find_lively_task_by_vpid(pid); 9894 if (IS_ERR(task)) { 9895 err = PTR_ERR(task); 9896 goto err_group_fd; 9897 } 9898 } 9899 9900 if (task && group_leader && 9901 group_leader->attr.inherit != attr.inherit) { 9902 err = -EINVAL; 9903 goto err_task; 9904 } 9905 9906 get_online_cpus(); 9907 9908 if (task) { 9909 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex); 9910 if (err) 9911 goto err_cpus; 9912 9913 /* 9914 * Reuse ptrace permission checks for now. 9915 * 9916 * We must hold cred_guard_mutex across this and any potential 9917 * perf_install_in_context() call for this new event to 9918 * serialize against exec() altering our credentials (and the 9919 * perf_event_exit_task() that could imply). 9920 */ 9921 err = -EACCES; 9922 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) 9923 goto err_cred; 9924 } 9925 9926 if (flags & PERF_FLAG_PID_CGROUP) 9927 cgroup_fd = pid; 9928 9929 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, 9930 NULL, NULL, cgroup_fd); 9931 if (IS_ERR(event)) { 9932 err = PTR_ERR(event); 9933 goto err_cred; 9934 } 9935 9936 if (is_sampling_event(event)) { 9937 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) { 9938 err = -EOPNOTSUPP; 9939 goto err_alloc; 9940 } 9941 } 9942 9943 /* 9944 * Special case software events and allow them to be part of 9945 * any hardware group. 9946 */ 9947 pmu = event->pmu; 9948 9949 if (attr.use_clockid) { 9950 err = perf_event_set_clock(event, attr.clockid); 9951 if (err) 9952 goto err_alloc; 9953 } 9954 9955 if (pmu->task_ctx_nr == perf_sw_context) 9956 event->event_caps |= PERF_EV_CAP_SOFTWARE; 9957 9958 if (group_leader && 9959 (is_software_event(event) != is_software_event(group_leader))) { 9960 if (is_software_event(event)) { 9961 /* 9962 * If event and group_leader are not both a software 9963 * event, and event is, then group leader is not. 9964 * 9965 * Allow the addition of software events to !software 9966 * groups, this is safe because software events never 9967 * fail to schedule. 9968 */ 9969 pmu = group_leader->pmu; 9970 } else if (is_software_event(group_leader) && 9971 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) { 9972 /* 9973 * In case the group is a pure software group, and we 9974 * try to add a hardware event, move the whole group to 9975 * the hardware context. 9976 */ 9977 move_group = 1; 9978 } 9979 } 9980 9981 /* 9982 * Get the target context (task or percpu): 9983 */ 9984 ctx = find_get_context(pmu, task, event); 9985 if (IS_ERR(ctx)) { 9986 err = PTR_ERR(ctx); 9987 goto err_alloc; 9988 } 9989 9990 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) { 9991 err = -EBUSY; 9992 goto err_context; 9993 } 9994 9995 /* 9996 * Look up the group leader (we will attach this event to it): 9997 */ 9998 if (group_leader) { 9999 err = -EINVAL; 10000 10001 /* 10002 * Do not allow a recursive hierarchy (this new sibling 10003 * becoming part of another group-sibling): 10004 */ 10005 if (group_leader->group_leader != group_leader) 10006 goto err_context; 10007 10008 /* All events in a group should have the same clock */ 10009 if (group_leader->clock != event->clock) 10010 goto err_context; 10011 10012 /* 10013 * Do not allow to attach to a group in a different 10014 * task or CPU context: 10015 */ 10016 if (move_group) { 10017 /* 10018 * Make sure we're both on the same task, or both 10019 * per-cpu events. 10020 */ 10021 if (group_leader->ctx->task != ctx->task) 10022 goto err_context; 10023 10024 /* 10025 * Make sure we're both events for the same CPU; 10026 * grouping events for different CPUs is broken; since 10027 * you can never concurrently schedule them anyhow. 10028 */ 10029 if (group_leader->cpu != event->cpu) 10030 goto err_context; 10031 } else { 10032 if (group_leader->ctx != ctx) 10033 goto err_context; 10034 } 10035 10036 /* 10037 * Only a group leader can be exclusive or pinned 10038 */ 10039 if (attr.exclusive || attr.pinned) 10040 goto err_context; 10041 } 10042 10043 if (output_event) { 10044 err = perf_event_set_output(event, output_event); 10045 if (err) 10046 goto err_context; 10047 } 10048 10049 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, 10050 f_flags); 10051 if (IS_ERR(event_file)) { 10052 err = PTR_ERR(event_file); 10053 event_file = NULL; 10054 goto err_context; 10055 } 10056 10057 if (move_group) { 10058 gctx = __perf_event_ctx_lock_double(group_leader, ctx); 10059 10060 if (gctx->task == TASK_TOMBSTONE) { 10061 err = -ESRCH; 10062 goto err_locked; 10063 } 10064 10065 /* 10066 * Check if we raced against another sys_perf_event_open() call 10067 * moving the software group underneath us. 10068 */ 10069 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) { 10070 /* 10071 * If someone moved the group out from under us, check 10072 * if this new event wound up on the same ctx, if so 10073 * its the regular !move_group case, otherwise fail. 10074 */ 10075 if (gctx != ctx) { 10076 err = -EINVAL; 10077 goto err_locked; 10078 } else { 10079 perf_event_ctx_unlock(group_leader, gctx); 10080 move_group = 0; 10081 } 10082 } 10083 } else { 10084 mutex_lock(&ctx->mutex); 10085 } 10086 10087 if (ctx->task == TASK_TOMBSTONE) { 10088 err = -ESRCH; 10089 goto err_locked; 10090 } 10091 10092 if (!perf_event_validate_size(event)) { 10093 err = -E2BIG; 10094 goto err_locked; 10095 } 10096 10097 /* 10098 * Must be under the same ctx::mutex as perf_install_in_context(), 10099 * because we need to serialize with concurrent event creation. 10100 */ 10101 if (!exclusive_event_installable(event, ctx)) { 10102 /* exclusive and group stuff are assumed mutually exclusive */ 10103 WARN_ON_ONCE(move_group); 10104 10105 err = -EBUSY; 10106 goto err_locked; 10107 } 10108 10109 WARN_ON_ONCE(ctx->parent_ctx); 10110 10111 /* 10112 * This is the point on no return; we cannot fail hereafter. This is 10113 * where we start modifying current state. 10114 */ 10115 10116 if (move_group) { 10117 /* 10118 * See perf_event_ctx_lock() for comments on the details 10119 * of swizzling perf_event::ctx. 10120 */ 10121 perf_remove_from_context(group_leader, 0); 10122 put_ctx(gctx); 10123 10124 list_for_each_entry(sibling, &group_leader->sibling_list, 10125 group_entry) { 10126 perf_remove_from_context(sibling, 0); 10127 put_ctx(gctx); 10128 } 10129 10130 /* 10131 * Wait for everybody to stop referencing the events through 10132 * the old lists, before installing it on new lists. 10133 */ 10134 synchronize_rcu(); 10135 10136 /* 10137 * Install the group siblings before the group leader. 10138 * 10139 * Because a group leader will try and install the entire group 10140 * (through the sibling list, which is still in-tact), we can 10141 * end up with siblings installed in the wrong context. 10142 * 10143 * By installing siblings first we NO-OP because they're not 10144 * reachable through the group lists. 10145 */ 10146 list_for_each_entry(sibling, &group_leader->sibling_list, 10147 group_entry) { 10148 perf_event__state_init(sibling); 10149 perf_install_in_context(ctx, sibling, sibling->cpu); 10150 get_ctx(ctx); 10151 } 10152 10153 /* 10154 * Removing from the context ends up with disabled 10155 * event. What we want here is event in the initial 10156 * startup state, ready to be add into new context. 10157 */ 10158 perf_event__state_init(group_leader); 10159 perf_install_in_context(ctx, group_leader, group_leader->cpu); 10160 get_ctx(ctx); 10161 } 10162 10163 /* 10164 * Precalculate sample_data sizes; do while holding ctx::mutex such 10165 * that we're serialized against further additions and before 10166 * perf_install_in_context() which is the point the event is active and 10167 * can use these values. 10168 */ 10169 perf_event__header_size(event); 10170 perf_event__id_header_size(event); 10171 10172 event->owner = current; 10173 10174 perf_install_in_context(ctx, event, event->cpu); 10175 perf_unpin_context(ctx); 10176 10177 if (move_group) 10178 perf_event_ctx_unlock(group_leader, gctx); 10179 mutex_unlock(&ctx->mutex); 10180 10181 if (task) { 10182 mutex_unlock(&task->signal->cred_guard_mutex); 10183 put_task_struct(task); 10184 } 10185 10186 put_online_cpus(); 10187 10188 mutex_lock(¤t->perf_event_mutex); 10189 list_add_tail(&event->owner_entry, ¤t->perf_event_list); 10190 mutex_unlock(¤t->perf_event_mutex); 10191 10192 /* 10193 * Drop the reference on the group_event after placing the 10194 * new event on the sibling_list. This ensures destruction 10195 * of the group leader will find the pointer to itself in 10196 * perf_group_detach(). 10197 */ 10198 fdput(group); 10199 fd_install(event_fd, event_file); 10200 return event_fd; 10201 10202 err_locked: 10203 if (move_group) 10204 perf_event_ctx_unlock(group_leader, gctx); 10205 mutex_unlock(&ctx->mutex); 10206 /* err_file: */ 10207 fput(event_file); 10208 err_context: 10209 perf_unpin_context(ctx); 10210 put_ctx(ctx); 10211 err_alloc: 10212 /* 10213 * If event_file is set, the fput() above will have called ->release() 10214 * and that will take care of freeing the event. 10215 */ 10216 if (!event_file) 10217 free_event(event); 10218 err_cred: 10219 if (task) 10220 mutex_unlock(&task->signal->cred_guard_mutex); 10221 err_cpus: 10222 put_online_cpus(); 10223 err_task: 10224 if (task) 10225 put_task_struct(task); 10226 err_group_fd: 10227 fdput(group); 10228 err_fd: 10229 put_unused_fd(event_fd); 10230 return err; 10231 } 10232 10233 /** 10234 * perf_event_create_kernel_counter 10235 * 10236 * @attr: attributes of the counter to create 10237 * @cpu: cpu in which the counter is bound 10238 * @task: task to profile (NULL for percpu) 10239 */ 10240 struct perf_event * 10241 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, 10242 struct task_struct *task, 10243 perf_overflow_handler_t overflow_handler, 10244 void *context) 10245 { 10246 struct perf_event_context *ctx; 10247 struct perf_event *event; 10248 int err; 10249 10250 /* 10251 * Get the target context (task or percpu): 10252 */ 10253 10254 event = perf_event_alloc(attr, cpu, task, NULL, NULL, 10255 overflow_handler, context, -1); 10256 if (IS_ERR(event)) { 10257 err = PTR_ERR(event); 10258 goto err; 10259 } 10260 10261 /* Mark owner so we could distinguish it from user events. */ 10262 event->owner = TASK_TOMBSTONE; 10263 10264 ctx = find_get_context(event->pmu, task, event); 10265 if (IS_ERR(ctx)) { 10266 err = PTR_ERR(ctx); 10267 goto err_free; 10268 } 10269 10270 WARN_ON_ONCE(ctx->parent_ctx); 10271 mutex_lock(&ctx->mutex); 10272 if (ctx->task == TASK_TOMBSTONE) { 10273 err = -ESRCH; 10274 goto err_unlock; 10275 } 10276 10277 if (!exclusive_event_installable(event, ctx)) { 10278 err = -EBUSY; 10279 goto err_unlock; 10280 } 10281 10282 perf_install_in_context(ctx, event, cpu); 10283 perf_unpin_context(ctx); 10284 mutex_unlock(&ctx->mutex); 10285 10286 return event; 10287 10288 err_unlock: 10289 mutex_unlock(&ctx->mutex); 10290 perf_unpin_context(ctx); 10291 put_ctx(ctx); 10292 err_free: 10293 free_event(event); 10294 err: 10295 return ERR_PTR(err); 10296 } 10297 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter); 10298 10299 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu) 10300 { 10301 struct perf_event_context *src_ctx; 10302 struct perf_event_context *dst_ctx; 10303 struct perf_event *event, *tmp; 10304 LIST_HEAD(events); 10305 10306 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx; 10307 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx; 10308 10309 /* 10310 * See perf_event_ctx_lock() for comments on the details 10311 * of swizzling perf_event::ctx. 10312 */ 10313 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex); 10314 list_for_each_entry_safe(event, tmp, &src_ctx->event_list, 10315 event_entry) { 10316 perf_remove_from_context(event, 0); 10317 unaccount_event_cpu(event, src_cpu); 10318 put_ctx(src_ctx); 10319 list_add(&event->migrate_entry, &events); 10320 } 10321 10322 /* 10323 * Wait for the events to quiesce before re-instating them. 10324 */ 10325 synchronize_rcu(); 10326 10327 /* 10328 * Re-instate events in 2 passes. 10329 * 10330 * Skip over group leaders and only install siblings on this first 10331 * pass, siblings will not get enabled without a leader, however a 10332 * leader will enable its siblings, even if those are still on the old 10333 * context. 10334 */ 10335 list_for_each_entry_safe(event, tmp, &events, migrate_entry) { 10336 if (event->group_leader == event) 10337 continue; 10338 10339 list_del(&event->migrate_entry); 10340 if (event->state >= PERF_EVENT_STATE_OFF) 10341 event->state = PERF_EVENT_STATE_INACTIVE; 10342 account_event_cpu(event, dst_cpu); 10343 perf_install_in_context(dst_ctx, event, dst_cpu); 10344 get_ctx(dst_ctx); 10345 } 10346 10347 /* 10348 * Once all the siblings are setup properly, install the group leaders 10349 * to make it go. 10350 */ 10351 list_for_each_entry_safe(event, tmp, &events, migrate_entry) { 10352 list_del(&event->migrate_entry); 10353 if (event->state >= PERF_EVENT_STATE_OFF) 10354 event->state = PERF_EVENT_STATE_INACTIVE; 10355 account_event_cpu(event, dst_cpu); 10356 perf_install_in_context(dst_ctx, event, dst_cpu); 10357 get_ctx(dst_ctx); 10358 } 10359 mutex_unlock(&dst_ctx->mutex); 10360 mutex_unlock(&src_ctx->mutex); 10361 } 10362 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context); 10363 10364 static void sync_child_event(struct perf_event *child_event, 10365 struct task_struct *child) 10366 { 10367 struct perf_event *parent_event = child_event->parent; 10368 u64 child_val; 10369 10370 if (child_event->attr.inherit_stat) 10371 perf_event_read_event(child_event, child); 10372 10373 child_val = perf_event_count(child_event); 10374 10375 /* 10376 * Add back the child's count to the parent's count: 10377 */ 10378 atomic64_add(child_val, &parent_event->child_count); 10379 atomic64_add(child_event->total_time_enabled, 10380 &parent_event->child_total_time_enabled); 10381 atomic64_add(child_event->total_time_running, 10382 &parent_event->child_total_time_running); 10383 } 10384 10385 static void 10386 perf_event_exit_event(struct perf_event *child_event, 10387 struct perf_event_context *child_ctx, 10388 struct task_struct *child) 10389 { 10390 struct perf_event *parent_event = child_event->parent; 10391 10392 /* 10393 * Do not destroy the 'original' grouping; because of the context 10394 * switch optimization the original events could've ended up in a 10395 * random child task. 10396 * 10397 * If we were to destroy the original group, all group related 10398 * operations would cease to function properly after this random 10399 * child dies. 10400 * 10401 * Do destroy all inherited groups, we don't care about those 10402 * and being thorough is better. 10403 */ 10404 raw_spin_lock_irq(&child_ctx->lock); 10405 WARN_ON_ONCE(child_ctx->is_active); 10406 10407 if (parent_event) 10408 perf_group_detach(child_event); 10409 list_del_event(child_event, child_ctx); 10410 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */ 10411 raw_spin_unlock_irq(&child_ctx->lock); 10412 10413 /* 10414 * Parent events are governed by their filedesc, retain them. 10415 */ 10416 if (!parent_event) { 10417 perf_event_wakeup(child_event); 10418 return; 10419 } 10420 /* 10421 * Child events can be cleaned up. 10422 */ 10423 10424 sync_child_event(child_event, child); 10425 10426 /* 10427 * Remove this event from the parent's list 10428 */ 10429 WARN_ON_ONCE(parent_event->ctx->parent_ctx); 10430 mutex_lock(&parent_event->child_mutex); 10431 list_del_init(&child_event->child_list); 10432 mutex_unlock(&parent_event->child_mutex); 10433 10434 /* 10435 * Kick perf_poll() for is_event_hup(). 10436 */ 10437 perf_event_wakeup(parent_event); 10438 free_event(child_event); 10439 put_event(parent_event); 10440 } 10441 10442 static void perf_event_exit_task_context(struct task_struct *child, int ctxn) 10443 { 10444 struct perf_event_context *child_ctx, *clone_ctx = NULL; 10445 struct perf_event *child_event, *next; 10446 10447 WARN_ON_ONCE(child != current); 10448 10449 child_ctx = perf_pin_task_context(child, ctxn); 10450 if (!child_ctx) 10451 return; 10452 10453 /* 10454 * In order to reduce the amount of tricky in ctx tear-down, we hold 10455 * ctx::mutex over the entire thing. This serializes against almost 10456 * everything that wants to access the ctx. 10457 * 10458 * The exception is sys_perf_event_open() / 10459 * perf_event_create_kernel_count() which does find_get_context() 10460 * without ctx::mutex (it cannot because of the move_group double mutex 10461 * lock thing). See the comments in perf_install_in_context(). 10462 */ 10463 mutex_lock(&child_ctx->mutex); 10464 10465 /* 10466 * In a single ctx::lock section, de-schedule the events and detach the 10467 * context from the task such that we cannot ever get it scheduled back 10468 * in. 10469 */ 10470 raw_spin_lock_irq(&child_ctx->lock); 10471 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL); 10472 10473 /* 10474 * Now that the context is inactive, destroy the task <-> ctx relation 10475 * and mark the context dead. 10476 */ 10477 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL); 10478 put_ctx(child_ctx); /* cannot be last */ 10479 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE); 10480 put_task_struct(current); /* cannot be last */ 10481 10482 clone_ctx = unclone_ctx(child_ctx); 10483 raw_spin_unlock_irq(&child_ctx->lock); 10484 10485 if (clone_ctx) 10486 put_ctx(clone_ctx); 10487 10488 /* 10489 * Report the task dead after unscheduling the events so that we 10490 * won't get any samples after PERF_RECORD_EXIT. We can however still 10491 * get a few PERF_RECORD_READ events. 10492 */ 10493 perf_event_task(child, child_ctx, 0); 10494 10495 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry) 10496 perf_event_exit_event(child_event, child_ctx, child); 10497 10498 mutex_unlock(&child_ctx->mutex); 10499 10500 put_ctx(child_ctx); 10501 } 10502 10503 /* 10504 * When a child task exits, feed back event values to parent events. 10505 * 10506 * Can be called with cred_guard_mutex held when called from 10507 * install_exec_creds(). 10508 */ 10509 void perf_event_exit_task(struct task_struct *child) 10510 { 10511 struct perf_event *event, *tmp; 10512 int ctxn; 10513 10514 mutex_lock(&child->perf_event_mutex); 10515 list_for_each_entry_safe(event, tmp, &child->perf_event_list, 10516 owner_entry) { 10517 list_del_init(&event->owner_entry); 10518 10519 /* 10520 * Ensure the list deletion is visible before we clear 10521 * the owner, closes a race against perf_release() where 10522 * we need to serialize on the owner->perf_event_mutex. 10523 */ 10524 smp_store_release(&event->owner, NULL); 10525 } 10526 mutex_unlock(&child->perf_event_mutex); 10527 10528 for_each_task_context_nr(ctxn) 10529 perf_event_exit_task_context(child, ctxn); 10530 10531 /* 10532 * The perf_event_exit_task_context calls perf_event_task 10533 * with child's task_ctx, which generates EXIT events for 10534 * child contexts and sets child->perf_event_ctxp[] to NULL. 10535 * At this point we need to send EXIT events to cpu contexts. 10536 */ 10537 perf_event_task(child, NULL, 0); 10538 } 10539 10540 static void perf_free_event(struct perf_event *event, 10541 struct perf_event_context *ctx) 10542 { 10543 struct perf_event *parent = event->parent; 10544 10545 if (WARN_ON_ONCE(!parent)) 10546 return; 10547 10548 mutex_lock(&parent->child_mutex); 10549 list_del_init(&event->child_list); 10550 mutex_unlock(&parent->child_mutex); 10551 10552 put_event(parent); 10553 10554 raw_spin_lock_irq(&ctx->lock); 10555 perf_group_detach(event); 10556 list_del_event(event, ctx); 10557 raw_spin_unlock_irq(&ctx->lock); 10558 free_event(event); 10559 } 10560 10561 /* 10562 * Free an unexposed, unused context as created by inheritance by 10563 * perf_event_init_task below, used by fork() in case of fail. 10564 * 10565 * Not all locks are strictly required, but take them anyway to be nice and 10566 * help out with the lockdep assertions. 10567 */ 10568 void perf_event_free_task(struct task_struct *task) 10569 { 10570 struct perf_event_context *ctx; 10571 struct perf_event *event, *tmp; 10572 int ctxn; 10573 10574 for_each_task_context_nr(ctxn) { 10575 ctx = task->perf_event_ctxp[ctxn]; 10576 if (!ctx) 10577 continue; 10578 10579 mutex_lock(&ctx->mutex); 10580 raw_spin_lock_irq(&ctx->lock); 10581 /* 10582 * Destroy the task <-> ctx relation and mark the context dead. 10583 * 10584 * This is important because even though the task hasn't been 10585 * exposed yet the context has been (through child_list). 10586 */ 10587 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL); 10588 WRITE_ONCE(ctx->task, TASK_TOMBSTONE); 10589 put_task_struct(task); /* cannot be last */ 10590 raw_spin_unlock_irq(&ctx->lock); 10591 10592 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) 10593 perf_free_event(event, ctx); 10594 10595 mutex_unlock(&ctx->mutex); 10596 put_ctx(ctx); 10597 } 10598 } 10599 10600 void perf_event_delayed_put(struct task_struct *task) 10601 { 10602 int ctxn; 10603 10604 for_each_task_context_nr(ctxn) 10605 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]); 10606 } 10607 10608 struct file *perf_event_get(unsigned int fd) 10609 { 10610 struct file *file; 10611 10612 file = fget_raw(fd); 10613 if (!file) 10614 return ERR_PTR(-EBADF); 10615 10616 if (file->f_op != &perf_fops) { 10617 fput(file); 10618 return ERR_PTR(-EBADF); 10619 } 10620 10621 return file; 10622 } 10623 10624 const struct perf_event_attr *perf_event_attrs(struct perf_event *event) 10625 { 10626 if (!event) 10627 return ERR_PTR(-EINVAL); 10628 10629 return &event->attr; 10630 } 10631 10632 /* 10633 * Inherit a event from parent task to child task. 10634 * 10635 * Returns: 10636 * - valid pointer on success 10637 * - NULL for orphaned events 10638 * - IS_ERR() on error 10639 */ 10640 static struct perf_event * 10641 inherit_event(struct perf_event *parent_event, 10642 struct task_struct *parent, 10643 struct perf_event_context *parent_ctx, 10644 struct task_struct *child, 10645 struct perf_event *group_leader, 10646 struct perf_event_context *child_ctx) 10647 { 10648 enum perf_event_active_state parent_state = parent_event->state; 10649 struct perf_event *child_event; 10650 unsigned long flags; 10651 10652 /* 10653 * Instead of creating recursive hierarchies of events, 10654 * we link inherited events back to the original parent, 10655 * which has a filp for sure, which we use as the reference 10656 * count: 10657 */ 10658 if (parent_event->parent) 10659 parent_event = parent_event->parent; 10660 10661 child_event = perf_event_alloc(&parent_event->attr, 10662 parent_event->cpu, 10663 child, 10664 group_leader, parent_event, 10665 NULL, NULL, -1); 10666 if (IS_ERR(child_event)) 10667 return child_event; 10668 10669 /* 10670 * is_orphaned_event() and list_add_tail(&parent_event->child_list) 10671 * must be under the same lock in order to serialize against 10672 * perf_event_release_kernel(), such that either we must observe 10673 * is_orphaned_event() or they will observe us on the child_list. 10674 */ 10675 mutex_lock(&parent_event->child_mutex); 10676 if (is_orphaned_event(parent_event) || 10677 !atomic_long_inc_not_zero(&parent_event->refcount)) { 10678 mutex_unlock(&parent_event->child_mutex); 10679 free_event(child_event); 10680 return NULL; 10681 } 10682 10683 get_ctx(child_ctx); 10684 10685 /* 10686 * Make the child state follow the state of the parent event, 10687 * not its attr.disabled bit. We hold the parent's mutex, 10688 * so we won't race with perf_event_{en, dis}able_family. 10689 */ 10690 if (parent_state >= PERF_EVENT_STATE_INACTIVE) 10691 child_event->state = PERF_EVENT_STATE_INACTIVE; 10692 else 10693 child_event->state = PERF_EVENT_STATE_OFF; 10694 10695 if (parent_event->attr.freq) { 10696 u64 sample_period = parent_event->hw.sample_period; 10697 struct hw_perf_event *hwc = &child_event->hw; 10698 10699 hwc->sample_period = sample_period; 10700 hwc->last_period = sample_period; 10701 10702 local64_set(&hwc->period_left, sample_period); 10703 } 10704 10705 child_event->ctx = child_ctx; 10706 child_event->overflow_handler = parent_event->overflow_handler; 10707 child_event->overflow_handler_context 10708 = parent_event->overflow_handler_context; 10709 10710 /* 10711 * Precalculate sample_data sizes 10712 */ 10713 perf_event__header_size(child_event); 10714 perf_event__id_header_size(child_event); 10715 10716 /* 10717 * Link it up in the child's context: 10718 */ 10719 raw_spin_lock_irqsave(&child_ctx->lock, flags); 10720 add_event_to_ctx(child_event, child_ctx); 10721 raw_spin_unlock_irqrestore(&child_ctx->lock, flags); 10722 10723 /* 10724 * Link this into the parent event's child list 10725 */ 10726 list_add_tail(&child_event->child_list, &parent_event->child_list); 10727 mutex_unlock(&parent_event->child_mutex); 10728 10729 return child_event; 10730 } 10731 10732 /* 10733 * Inherits an event group. 10734 * 10735 * This will quietly suppress orphaned events; !inherit_event() is not an error. 10736 * This matches with perf_event_release_kernel() removing all child events. 10737 * 10738 * Returns: 10739 * - 0 on success 10740 * - <0 on error 10741 */ 10742 static int inherit_group(struct perf_event *parent_event, 10743 struct task_struct *parent, 10744 struct perf_event_context *parent_ctx, 10745 struct task_struct *child, 10746 struct perf_event_context *child_ctx) 10747 { 10748 struct perf_event *leader; 10749 struct perf_event *sub; 10750 struct perf_event *child_ctr; 10751 10752 leader = inherit_event(parent_event, parent, parent_ctx, 10753 child, NULL, child_ctx); 10754 if (IS_ERR(leader)) 10755 return PTR_ERR(leader); 10756 /* 10757 * @leader can be NULL here because of is_orphaned_event(). In this 10758 * case inherit_event() will create individual events, similar to what 10759 * perf_group_detach() would do anyway. 10760 */ 10761 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) { 10762 child_ctr = inherit_event(sub, parent, parent_ctx, 10763 child, leader, child_ctx); 10764 if (IS_ERR(child_ctr)) 10765 return PTR_ERR(child_ctr); 10766 } 10767 return 0; 10768 } 10769 10770 /* 10771 * Creates the child task context and tries to inherit the event-group. 10772 * 10773 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave 10774 * inherited_all set when we 'fail' to inherit an orphaned event; this is 10775 * consistent with perf_event_release_kernel() removing all child events. 10776 * 10777 * Returns: 10778 * - 0 on success 10779 * - <0 on error 10780 */ 10781 static int 10782 inherit_task_group(struct perf_event *event, struct task_struct *parent, 10783 struct perf_event_context *parent_ctx, 10784 struct task_struct *child, int ctxn, 10785 int *inherited_all) 10786 { 10787 int ret; 10788 struct perf_event_context *child_ctx; 10789 10790 if (!event->attr.inherit) { 10791 *inherited_all = 0; 10792 return 0; 10793 } 10794 10795 child_ctx = child->perf_event_ctxp[ctxn]; 10796 if (!child_ctx) { 10797 /* 10798 * This is executed from the parent task context, so 10799 * inherit events that have been marked for cloning. 10800 * First allocate and initialize a context for the 10801 * child. 10802 */ 10803 child_ctx = alloc_perf_context(parent_ctx->pmu, child); 10804 if (!child_ctx) 10805 return -ENOMEM; 10806 10807 child->perf_event_ctxp[ctxn] = child_ctx; 10808 } 10809 10810 ret = inherit_group(event, parent, parent_ctx, 10811 child, child_ctx); 10812 10813 if (ret) 10814 *inherited_all = 0; 10815 10816 return ret; 10817 } 10818 10819 /* 10820 * Initialize the perf_event context in task_struct 10821 */ 10822 static int perf_event_init_context(struct task_struct *child, int ctxn) 10823 { 10824 struct perf_event_context *child_ctx, *parent_ctx; 10825 struct perf_event_context *cloned_ctx; 10826 struct perf_event *event; 10827 struct task_struct *parent = current; 10828 int inherited_all = 1; 10829 unsigned long flags; 10830 int ret = 0; 10831 10832 if (likely(!parent->perf_event_ctxp[ctxn])) 10833 return 0; 10834 10835 /* 10836 * If the parent's context is a clone, pin it so it won't get 10837 * swapped under us. 10838 */ 10839 parent_ctx = perf_pin_task_context(parent, ctxn); 10840 if (!parent_ctx) 10841 return 0; 10842 10843 /* 10844 * No need to check if parent_ctx != NULL here; since we saw 10845 * it non-NULL earlier, the only reason for it to become NULL 10846 * is if we exit, and since we're currently in the middle of 10847 * a fork we can't be exiting at the same time. 10848 */ 10849 10850 /* 10851 * Lock the parent list. No need to lock the child - not PID 10852 * hashed yet and not running, so nobody can access it. 10853 */ 10854 mutex_lock(&parent_ctx->mutex); 10855 10856 /* 10857 * We dont have to disable NMIs - we are only looking at 10858 * the list, not manipulating it: 10859 */ 10860 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) { 10861 ret = inherit_task_group(event, parent, parent_ctx, 10862 child, ctxn, &inherited_all); 10863 if (ret) 10864 goto out_unlock; 10865 } 10866 10867 /* 10868 * We can't hold ctx->lock when iterating the ->flexible_group list due 10869 * to allocations, but we need to prevent rotation because 10870 * rotate_ctx() will change the list from interrupt context. 10871 */ 10872 raw_spin_lock_irqsave(&parent_ctx->lock, flags); 10873 parent_ctx->rotate_disable = 1; 10874 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); 10875 10876 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) { 10877 ret = inherit_task_group(event, parent, parent_ctx, 10878 child, ctxn, &inherited_all); 10879 if (ret) 10880 goto out_unlock; 10881 } 10882 10883 raw_spin_lock_irqsave(&parent_ctx->lock, flags); 10884 parent_ctx->rotate_disable = 0; 10885 10886 child_ctx = child->perf_event_ctxp[ctxn]; 10887 10888 if (child_ctx && inherited_all) { 10889 /* 10890 * Mark the child context as a clone of the parent 10891 * context, or of whatever the parent is a clone of. 10892 * 10893 * Note that if the parent is a clone, the holding of 10894 * parent_ctx->lock avoids it from being uncloned. 10895 */ 10896 cloned_ctx = parent_ctx->parent_ctx; 10897 if (cloned_ctx) { 10898 child_ctx->parent_ctx = cloned_ctx; 10899 child_ctx->parent_gen = parent_ctx->parent_gen; 10900 } else { 10901 child_ctx->parent_ctx = parent_ctx; 10902 child_ctx->parent_gen = parent_ctx->generation; 10903 } 10904 get_ctx(child_ctx->parent_ctx); 10905 } 10906 10907 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); 10908 out_unlock: 10909 mutex_unlock(&parent_ctx->mutex); 10910 10911 perf_unpin_context(parent_ctx); 10912 put_ctx(parent_ctx); 10913 10914 return ret; 10915 } 10916 10917 /* 10918 * Initialize the perf_event context in task_struct 10919 */ 10920 int perf_event_init_task(struct task_struct *child) 10921 { 10922 int ctxn, ret; 10923 10924 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp)); 10925 mutex_init(&child->perf_event_mutex); 10926 INIT_LIST_HEAD(&child->perf_event_list); 10927 10928 for_each_task_context_nr(ctxn) { 10929 ret = perf_event_init_context(child, ctxn); 10930 if (ret) { 10931 perf_event_free_task(child); 10932 return ret; 10933 } 10934 } 10935 10936 return 0; 10937 } 10938 10939 static void __init perf_event_init_all_cpus(void) 10940 { 10941 struct swevent_htable *swhash; 10942 int cpu; 10943 10944 for_each_possible_cpu(cpu) { 10945 swhash = &per_cpu(swevent_htable, cpu); 10946 mutex_init(&swhash->hlist_mutex); 10947 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu)); 10948 10949 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu)); 10950 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu)); 10951 10952 #ifdef CONFIG_CGROUP_PERF 10953 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu)); 10954 #endif 10955 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu)); 10956 } 10957 } 10958 10959 int perf_event_init_cpu(unsigned int cpu) 10960 { 10961 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 10962 10963 mutex_lock(&swhash->hlist_mutex); 10964 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) { 10965 struct swevent_hlist *hlist; 10966 10967 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu)); 10968 WARN_ON(!hlist); 10969 rcu_assign_pointer(swhash->swevent_hlist, hlist); 10970 } 10971 mutex_unlock(&swhash->hlist_mutex); 10972 return 0; 10973 } 10974 10975 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE 10976 static void __perf_event_exit_context(void *__info) 10977 { 10978 struct perf_event_context *ctx = __info; 10979 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 10980 struct perf_event *event; 10981 10982 raw_spin_lock(&ctx->lock); 10983 list_for_each_entry(event, &ctx->event_list, event_entry) 10984 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP); 10985 raw_spin_unlock(&ctx->lock); 10986 } 10987 10988 static void perf_event_exit_cpu_context(int cpu) 10989 { 10990 struct perf_event_context *ctx; 10991 struct pmu *pmu; 10992 int idx; 10993 10994 idx = srcu_read_lock(&pmus_srcu); 10995 list_for_each_entry_rcu(pmu, &pmus, entry) { 10996 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx; 10997 10998 mutex_lock(&ctx->mutex); 10999 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1); 11000 mutex_unlock(&ctx->mutex); 11001 } 11002 srcu_read_unlock(&pmus_srcu, idx); 11003 } 11004 #else 11005 11006 static void perf_event_exit_cpu_context(int cpu) { } 11007 11008 #endif 11009 11010 int perf_event_exit_cpu(unsigned int cpu) 11011 { 11012 perf_event_exit_cpu_context(cpu); 11013 return 0; 11014 } 11015 11016 static int 11017 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v) 11018 { 11019 int cpu; 11020 11021 for_each_online_cpu(cpu) 11022 perf_event_exit_cpu(cpu); 11023 11024 return NOTIFY_OK; 11025 } 11026 11027 /* 11028 * Run the perf reboot notifier at the very last possible moment so that 11029 * the generic watchdog code runs as long as possible. 11030 */ 11031 static struct notifier_block perf_reboot_notifier = { 11032 .notifier_call = perf_reboot, 11033 .priority = INT_MIN, 11034 }; 11035 11036 void __init perf_event_init(void) 11037 { 11038 int ret; 11039 11040 idr_init(&pmu_idr); 11041 11042 perf_event_init_all_cpus(); 11043 init_srcu_struct(&pmus_srcu); 11044 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE); 11045 perf_pmu_register(&perf_cpu_clock, NULL, -1); 11046 perf_pmu_register(&perf_task_clock, NULL, -1); 11047 perf_tp_register(); 11048 perf_event_init_cpu(smp_processor_id()); 11049 register_reboot_notifier(&perf_reboot_notifier); 11050 11051 ret = init_hw_breakpoint(); 11052 WARN(ret, "hw_breakpoint initialization failed with: %d", ret); 11053 11054 /* 11055 * Build time assertion that we keep the data_head at the intended 11056 * location. IOW, validation we got the __reserved[] size right. 11057 */ 11058 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head)) 11059 != 1024); 11060 } 11061 11062 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr, 11063 char *page) 11064 { 11065 struct perf_pmu_events_attr *pmu_attr = 11066 container_of(attr, struct perf_pmu_events_attr, attr); 11067 11068 if (pmu_attr->event_str) 11069 return sprintf(page, "%s\n", pmu_attr->event_str); 11070 11071 return 0; 11072 } 11073 EXPORT_SYMBOL_GPL(perf_event_sysfs_show); 11074 11075 static int __init perf_event_sysfs_init(void) 11076 { 11077 struct pmu *pmu; 11078 int ret; 11079 11080 mutex_lock(&pmus_lock); 11081 11082 ret = bus_register(&pmu_bus); 11083 if (ret) 11084 goto unlock; 11085 11086 list_for_each_entry(pmu, &pmus, entry) { 11087 if (!pmu->name || pmu->type < 0) 11088 continue; 11089 11090 ret = pmu_dev_alloc(pmu); 11091 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret); 11092 } 11093 pmu_bus_running = 1; 11094 ret = 0; 11095 11096 unlock: 11097 mutex_unlock(&pmus_lock); 11098 11099 return ret; 11100 } 11101 device_initcall(perf_event_sysfs_init); 11102 11103 #ifdef CONFIG_CGROUP_PERF 11104 static struct cgroup_subsys_state * 11105 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) 11106 { 11107 struct perf_cgroup *jc; 11108 11109 jc = kzalloc(sizeof(*jc), GFP_KERNEL); 11110 if (!jc) 11111 return ERR_PTR(-ENOMEM); 11112 11113 jc->info = alloc_percpu(struct perf_cgroup_info); 11114 if (!jc->info) { 11115 kfree(jc); 11116 return ERR_PTR(-ENOMEM); 11117 } 11118 11119 return &jc->css; 11120 } 11121 11122 static void perf_cgroup_css_free(struct cgroup_subsys_state *css) 11123 { 11124 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css); 11125 11126 free_percpu(jc->info); 11127 kfree(jc); 11128 } 11129 11130 static int __perf_cgroup_move(void *info) 11131 { 11132 struct task_struct *task = info; 11133 rcu_read_lock(); 11134 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN); 11135 rcu_read_unlock(); 11136 return 0; 11137 } 11138 11139 static void perf_cgroup_attach(struct cgroup_taskset *tset) 11140 { 11141 struct task_struct *task; 11142 struct cgroup_subsys_state *css; 11143 11144 cgroup_taskset_for_each(task, css, tset) 11145 task_function_call(task, __perf_cgroup_move, task); 11146 } 11147 11148 struct cgroup_subsys perf_event_cgrp_subsys = { 11149 .css_alloc = perf_cgroup_css_alloc, 11150 .css_free = perf_cgroup_css_free, 11151 .attach = perf_cgroup_attach, 11152 /* 11153 * Implicitly enable on dfl hierarchy so that perf events can 11154 * always be filtered by cgroup2 path as long as perf_event 11155 * controller is not mounted on a legacy hierarchy. 11156 */ 11157 .implicit_on_dfl = true, 11158 }; 11159 #endif /* CONFIG_CGROUP_PERF */ 11160