1 /* 2 * Performance events core code: 3 * 4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de> 5 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar 6 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra 7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com> 8 * 9 * For licensing details see kernel-base/COPYING 10 */ 11 12 #include <linux/fs.h> 13 #include <linux/mm.h> 14 #include <linux/cpu.h> 15 #include <linux/smp.h> 16 #include <linux/idr.h> 17 #include <linux/file.h> 18 #include <linux/poll.h> 19 #include <linux/slab.h> 20 #include <linux/hash.h> 21 #include <linux/tick.h> 22 #include <linux/sysfs.h> 23 #include <linux/dcache.h> 24 #include <linux/percpu.h> 25 #include <linux/ptrace.h> 26 #include <linux/reboot.h> 27 #include <linux/vmstat.h> 28 #include <linux/device.h> 29 #include <linux/export.h> 30 #include <linux/vmalloc.h> 31 #include <linux/hardirq.h> 32 #include <linux/rculist.h> 33 #include <linux/uaccess.h> 34 #include <linux/syscalls.h> 35 #include <linux/anon_inodes.h> 36 #include <linux/kernel_stat.h> 37 #include <linux/cgroup.h> 38 #include <linux/perf_event.h> 39 #include <linux/trace_events.h> 40 #include <linux/hw_breakpoint.h> 41 #include <linux/mm_types.h> 42 #include <linux/module.h> 43 #include <linux/mman.h> 44 #include <linux/compat.h> 45 #include <linux/bpf.h> 46 #include <linux/filter.h> 47 #include <linux/namei.h> 48 #include <linux/parser.h> 49 50 #include "internal.h" 51 52 #include <asm/irq_regs.h> 53 54 typedef int (*remote_function_f)(void *); 55 56 struct remote_function_call { 57 struct task_struct *p; 58 remote_function_f func; 59 void *info; 60 int ret; 61 }; 62 63 static void remote_function(void *data) 64 { 65 struct remote_function_call *tfc = data; 66 struct task_struct *p = tfc->p; 67 68 if (p) { 69 /* -EAGAIN */ 70 if (task_cpu(p) != smp_processor_id()) 71 return; 72 73 /* 74 * Now that we're on right CPU with IRQs disabled, we can test 75 * if we hit the right task without races. 76 */ 77 78 tfc->ret = -ESRCH; /* No such (running) process */ 79 if (p != current) 80 return; 81 } 82 83 tfc->ret = tfc->func(tfc->info); 84 } 85 86 /** 87 * task_function_call - call a function on the cpu on which a task runs 88 * @p: the task to evaluate 89 * @func: the function to be called 90 * @info: the function call argument 91 * 92 * Calls the function @func when the task is currently running. This might 93 * be on the current CPU, which just calls the function directly 94 * 95 * returns: @func return value, or 96 * -ESRCH - when the process isn't running 97 * -EAGAIN - when the process moved away 98 */ 99 static int 100 task_function_call(struct task_struct *p, remote_function_f func, void *info) 101 { 102 struct remote_function_call data = { 103 .p = p, 104 .func = func, 105 .info = info, 106 .ret = -EAGAIN, 107 }; 108 int ret; 109 110 do { 111 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1); 112 if (!ret) 113 ret = data.ret; 114 } while (ret == -EAGAIN); 115 116 return ret; 117 } 118 119 /** 120 * cpu_function_call - call a function on the cpu 121 * @func: the function to be called 122 * @info: the function call argument 123 * 124 * Calls the function @func on the remote cpu. 125 * 126 * returns: @func return value or -ENXIO when the cpu is offline 127 */ 128 static int cpu_function_call(int cpu, remote_function_f func, void *info) 129 { 130 struct remote_function_call data = { 131 .p = NULL, 132 .func = func, 133 .info = info, 134 .ret = -ENXIO, /* No such CPU */ 135 }; 136 137 smp_call_function_single(cpu, remote_function, &data, 1); 138 139 return data.ret; 140 } 141 142 static inline struct perf_cpu_context * 143 __get_cpu_context(struct perf_event_context *ctx) 144 { 145 return this_cpu_ptr(ctx->pmu->pmu_cpu_context); 146 } 147 148 static void perf_ctx_lock(struct perf_cpu_context *cpuctx, 149 struct perf_event_context *ctx) 150 { 151 raw_spin_lock(&cpuctx->ctx.lock); 152 if (ctx) 153 raw_spin_lock(&ctx->lock); 154 } 155 156 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx, 157 struct perf_event_context *ctx) 158 { 159 if (ctx) 160 raw_spin_unlock(&ctx->lock); 161 raw_spin_unlock(&cpuctx->ctx.lock); 162 } 163 164 #define TASK_TOMBSTONE ((void *)-1L) 165 166 static bool is_kernel_event(struct perf_event *event) 167 { 168 return READ_ONCE(event->owner) == TASK_TOMBSTONE; 169 } 170 171 /* 172 * On task ctx scheduling... 173 * 174 * When !ctx->nr_events a task context will not be scheduled. This means 175 * we can disable the scheduler hooks (for performance) without leaving 176 * pending task ctx state. 177 * 178 * This however results in two special cases: 179 * 180 * - removing the last event from a task ctx; this is relatively straight 181 * forward and is done in __perf_remove_from_context. 182 * 183 * - adding the first event to a task ctx; this is tricky because we cannot 184 * rely on ctx->is_active and therefore cannot use event_function_call(). 185 * See perf_install_in_context(). 186 * 187 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set. 188 */ 189 190 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *, 191 struct perf_event_context *, void *); 192 193 struct event_function_struct { 194 struct perf_event *event; 195 event_f func; 196 void *data; 197 }; 198 199 static int event_function(void *info) 200 { 201 struct event_function_struct *efs = info; 202 struct perf_event *event = efs->event; 203 struct perf_event_context *ctx = event->ctx; 204 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 205 struct perf_event_context *task_ctx = cpuctx->task_ctx; 206 int ret = 0; 207 208 WARN_ON_ONCE(!irqs_disabled()); 209 210 perf_ctx_lock(cpuctx, task_ctx); 211 /* 212 * Since we do the IPI call without holding ctx->lock things can have 213 * changed, double check we hit the task we set out to hit. 214 */ 215 if (ctx->task) { 216 if (ctx->task != current) { 217 ret = -ESRCH; 218 goto unlock; 219 } 220 221 /* 222 * We only use event_function_call() on established contexts, 223 * and event_function() is only ever called when active (or 224 * rather, we'll have bailed in task_function_call() or the 225 * above ctx->task != current test), therefore we must have 226 * ctx->is_active here. 227 */ 228 WARN_ON_ONCE(!ctx->is_active); 229 /* 230 * And since we have ctx->is_active, cpuctx->task_ctx must 231 * match. 232 */ 233 WARN_ON_ONCE(task_ctx != ctx); 234 } else { 235 WARN_ON_ONCE(&cpuctx->ctx != ctx); 236 } 237 238 efs->func(event, cpuctx, ctx, efs->data); 239 unlock: 240 perf_ctx_unlock(cpuctx, task_ctx); 241 242 return ret; 243 } 244 245 static void event_function_call(struct perf_event *event, event_f func, void *data) 246 { 247 struct perf_event_context *ctx = event->ctx; 248 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */ 249 struct event_function_struct efs = { 250 .event = event, 251 .func = func, 252 .data = data, 253 }; 254 255 if (!event->parent) { 256 /* 257 * If this is a !child event, we must hold ctx::mutex to 258 * stabilize the the event->ctx relation. See 259 * perf_event_ctx_lock(). 260 */ 261 lockdep_assert_held(&ctx->mutex); 262 } 263 264 if (!task) { 265 cpu_function_call(event->cpu, event_function, &efs); 266 return; 267 } 268 269 if (task == TASK_TOMBSTONE) 270 return; 271 272 again: 273 if (!task_function_call(task, event_function, &efs)) 274 return; 275 276 raw_spin_lock_irq(&ctx->lock); 277 /* 278 * Reload the task pointer, it might have been changed by 279 * a concurrent perf_event_context_sched_out(). 280 */ 281 task = ctx->task; 282 if (task == TASK_TOMBSTONE) { 283 raw_spin_unlock_irq(&ctx->lock); 284 return; 285 } 286 if (ctx->is_active) { 287 raw_spin_unlock_irq(&ctx->lock); 288 goto again; 289 } 290 func(event, NULL, ctx, data); 291 raw_spin_unlock_irq(&ctx->lock); 292 } 293 294 /* 295 * Similar to event_function_call() + event_function(), but hard assumes IRQs 296 * are already disabled and we're on the right CPU. 297 */ 298 static void event_function_local(struct perf_event *event, event_f func, void *data) 299 { 300 struct perf_event_context *ctx = event->ctx; 301 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 302 struct task_struct *task = READ_ONCE(ctx->task); 303 struct perf_event_context *task_ctx = NULL; 304 305 WARN_ON_ONCE(!irqs_disabled()); 306 307 if (task) { 308 if (task == TASK_TOMBSTONE) 309 return; 310 311 task_ctx = ctx; 312 } 313 314 perf_ctx_lock(cpuctx, task_ctx); 315 316 task = ctx->task; 317 if (task == TASK_TOMBSTONE) 318 goto unlock; 319 320 if (task) { 321 /* 322 * We must be either inactive or active and the right task, 323 * otherwise we're screwed, since we cannot IPI to somewhere 324 * else. 325 */ 326 if (ctx->is_active) { 327 if (WARN_ON_ONCE(task != current)) 328 goto unlock; 329 330 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx)) 331 goto unlock; 332 } 333 } else { 334 WARN_ON_ONCE(&cpuctx->ctx != ctx); 335 } 336 337 func(event, cpuctx, ctx, data); 338 unlock: 339 perf_ctx_unlock(cpuctx, task_ctx); 340 } 341 342 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\ 343 PERF_FLAG_FD_OUTPUT |\ 344 PERF_FLAG_PID_CGROUP |\ 345 PERF_FLAG_FD_CLOEXEC) 346 347 /* 348 * branch priv levels that need permission checks 349 */ 350 #define PERF_SAMPLE_BRANCH_PERM_PLM \ 351 (PERF_SAMPLE_BRANCH_KERNEL |\ 352 PERF_SAMPLE_BRANCH_HV) 353 354 enum event_type_t { 355 EVENT_FLEXIBLE = 0x1, 356 EVENT_PINNED = 0x2, 357 EVENT_TIME = 0x4, 358 /* see ctx_resched() for details */ 359 EVENT_CPU = 0x8, 360 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED, 361 }; 362 363 /* 364 * perf_sched_events : >0 events exist 365 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu 366 */ 367 368 static void perf_sched_delayed(struct work_struct *work); 369 DEFINE_STATIC_KEY_FALSE(perf_sched_events); 370 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed); 371 static DEFINE_MUTEX(perf_sched_mutex); 372 static atomic_t perf_sched_count; 373 374 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events); 375 static DEFINE_PER_CPU(int, perf_sched_cb_usages); 376 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events); 377 378 static atomic_t nr_mmap_events __read_mostly; 379 static atomic_t nr_comm_events __read_mostly; 380 static atomic_t nr_task_events __read_mostly; 381 static atomic_t nr_freq_events __read_mostly; 382 static atomic_t nr_switch_events __read_mostly; 383 384 static LIST_HEAD(pmus); 385 static DEFINE_MUTEX(pmus_lock); 386 static struct srcu_struct pmus_srcu; 387 388 /* 389 * perf event paranoia level: 390 * -1 - not paranoid at all 391 * 0 - disallow raw tracepoint access for unpriv 392 * 1 - disallow cpu events for unpriv 393 * 2 - disallow kernel profiling for unpriv 394 */ 395 int sysctl_perf_event_paranoid __read_mostly = 2; 396 397 /* Minimum for 512 kiB + 1 user control page */ 398 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */ 399 400 /* 401 * max perf event sample rate 402 */ 403 #define DEFAULT_MAX_SAMPLE_RATE 100000 404 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE) 405 #define DEFAULT_CPU_TIME_MAX_PERCENT 25 406 407 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE; 408 409 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ); 410 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS; 411 412 static int perf_sample_allowed_ns __read_mostly = 413 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100; 414 415 static void update_perf_cpu_limits(void) 416 { 417 u64 tmp = perf_sample_period_ns; 418 419 tmp *= sysctl_perf_cpu_time_max_percent; 420 tmp = div_u64(tmp, 100); 421 if (!tmp) 422 tmp = 1; 423 424 WRITE_ONCE(perf_sample_allowed_ns, tmp); 425 } 426 427 static int perf_rotate_context(struct perf_cpu_context *cpuctx); 428 429 int perf_proc_update_handler(struct ctl_table *table, int write, 430 void __user *buffer, size_t *lenp, 431 loff_t *ppos) 432 { 433 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); 434 435 if (ret || !write) 436 return ret; 437 438 /* 439 * If throttling is disabled don't allow the write: 440 */ 441 if (sysctl_perf_cpu_time_max_percent == 100 || 442 sysctl_perf_cpu_time_max_percent == 0) 443 return -EINVAL; 444 445 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ); 446 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; 447 update_perf_cpu_limits(); 448 449 return 0; 450 } 451 452 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT; 453 454 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write, 455 void __user *buffer, size_t *lenp, 456 loff_t *ppos) 457 { 458 int ret = proc_dointvec(table, write, buffer, lenp, ppos); 459 460 if (ret || !write) 461 return ret; 462 463 if (sysctl_perf_cpu_time_max_percent == 100 || 464 sysctl_perf_cpu_time_max_percent == 0) { 465 printk(KERN_WARNING 466 "perf: Dynamic interrupt throttling disabled, can hang your system!\n"); 467 WRITE_ONCE(perf_sample_allowed_ns, 0); 468 } else { 469 update_perf_cpu_limits(); 470 } 471 472 return 0; 473 } 474 475 /* 476 * perf samples are done in some very critical code paths (NMIs). 477 * If they take too much CPU time, the system can lock up and not 478 * get any real work done. This will drop the sample rate when 479 * we detect that events are taking too long. 480 */ 481 #define NR_ACCUMULATED_SAMPLES 128 482 static DEFINE_PER_CPU(u64, running_sample_length); 483 484 static u64 __report_avg; 485 static u64 __report_allowed; 486 487 static void perf_duration_warn(struct irq_work *w) 488 { 489 printk_ratelimited(KERN_INFO 490 "perf: interrupt took too long (%lld > %lld), lowering " 491 "kernel.perf_event_max_sample_rate to %d\n", 492 __report_avg, __report_allowed, 493 sysctl_perf_event_sample_rate); 494 } 495 496 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn); 497 498 void perf_sample_event_took(u64 sample_len_ns) 499 { 500 u64 max_len = READ_ONCE(perf_sample_allowed_ns); 501 u64 running_len; 502 u64 avg_len; 503 u32 max; 504 505 if (max_len == 0) 506 return; 507 508 /* Decay the counter by 1 average sample. */ 509 running_len = __this_cpu_read(running_sample_length); 510 running_len -= running_len/NR_ACCUMULATED_SAMPLES; 511 running_len += sample_len_ns; 512 __this_cpu_write(running_sample_length, running_len); 513 514 /* 515 * Note: this will be biased artifically low until we have 516 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us 517 * from having to maintain a count. 518 */ 519 avg_len = running_len/NR_ACCUMULATED_SAMPLES; 520 if (avg_len <= max_len) 521 return; 522 523 __report_avg = avg_len; 524 __report_allowed = max_len; 525 526 /* 527 * Compute a throttle threshold 25% below the current duration. 528 */ 529 avg_len += avg_len / 4; 530 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent; 531 if (avg_len < max) 532 max /= (u32)avg_len; 533 else 534 max = 1; 535 536 WRITE_ONCE(perf_sample_allowed_ns, avg_len); 537 WRITE_ONCE(max_samples_per_tick, max); 538 539 sysctl_perf_event_sample_rate = max * HZ; 540 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; 541 542 if (!irq_work_queue(&perf_duration_work)) { 543 early_printk("perf: interrupt took too long (%lld > %lld), lowering " 544 "kernel.perf_event_max_sample_rate to %d\n", 545 __report_avg, __report_allowed, 546 sysctl_perf_event_sample_rate); 547 } 548 } 549 550 static atomic64_t perf_event_id; 551 552 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, 553 enum event_type_t event_type); 554 555 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, 556 enum event_type_t event_type, 557 struct task_struct *task); 558 559 static void update_context_time(struct perf_event_context *ctx); 560 static u64 perf_event_time(struct perf_event *event); 561 562 void __weak perf_event_print_debug(void) { } 563 564 extern __weak const char *perf_pmu_name(void) 565 { 566 return "pmu"; 567 } 568 569 static inline u64 perf_clock(void) 570 { 571 return local_clock(); 572 } 573 574 static inline u64 perf_event_clock(struct perf_event *event) 575 { 576 return event->clock(); 577 } 578 579 #ifdef CONFIG_CGROUP_PERF 580 581 static inline bool 582 perf_cgroup_match(struct perf_event *event) 583 { 584 struct perf_event_context *ctx = event->ctx; 585 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 586 587 /* @event doesn't care about cgroup */ 588 if (!event->cgrp) 589 return true; 590 591 /* wants specific cgroup scope but @cpuctx isn't associated with any */ 592 if (!cpuctx->cgrp) 593 return false; 594 595 /* 596 * Cgroup scoping is recursive. An event enabled for a cgroup is 597 * also enabled for all its descendant cgroups. If @cpuctx's 598 * cgroup is a descendant of @event's (the test covers identity 599 * case), it's a match. 600 */ 601 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup, 602 event->cgrp->css.cgroup); 603 } 604 605 static inline void perf_detach_cgroup(struct perf_event *event) 606 { 607 css_put(&event->cgrp->css); 608 event->cgrp = NULL; 609 } 610 611 static inline int is_cgroup_event(struct perf_event *event) 612 { 613 return event->cgrp != NULL; 614 } 615 616 static inline u64 perf_cgroup_event_time(struct perf_event *event) 617 { 618 struct perf_cgroup_info *t; 619 620 t = per_cpu_ptr(event->cgrp->info, event->cpu); 621 return t->time; 622 } 623 624 static inline void __update_cgrp_time(struct perf_cgroup *cgrp) 625 { 626 struct perf_cgroup_info *info; 627 u64 now; 628 629 now = perf_clock(); 630 631 info = this_cpu_ptr(cgrp->info); 632 633 info->time += now - info->timestamp; 634 info->timestamp = now; 635 } 636 637 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) 638 { 639 struct perf_cgroup *cgrp_out = cpuctx->cgrp; 640 if (cgrp_out) 641 __update_cgrp_time(cgrp_out); 642 } 643 644 static inline void update_cgrp_time_from_event(struct perf_event *event) 645 { 646 struct perf_cgroup *cgrp; 647 648 /* 649 * ensure we access cgroup data only when needed and 650 * when we know the cgroup is pinned (css_get) 651 */ 652 if (!is_cgroup_event(event)) 653 return; 654 655 cgrp = perf_cgroup_from_task(current, event->ctx); 656 /* 657 * Do not update time when cgroup is not active 658 */ 659 if (cgrp == event->cgrp) 660 __update_cgrp_time(event->cgrp); 661 } 662 663 static inline void 664 perf_cgroup_set_timestamp(struct task_struct *task, 665 struct perf_event_context *ctx) 666 { 667 struct perf_cgroup *cgrp; 668 struct perf_cgroup_info *info; 669 670 /* 671 * ctx->lock held by caller 672 * ensure we do not access cgroup data 673 * unless we have the cgroup pinned (css_get) 674 */ 675 if (!task || !ctx->nr_cgroups) 676 return; 677 678 cgrp = perf_cgroup_from_task(task, ctx); 679 info = this_cpu_ptr(cgrp->info); 680 info->timestamp = ctx->timestamp; 681 } 682 683 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list); 684 685 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */ 686 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */ 687 688 /* 689 * reschedule events based on the cgroup constraint of task. 690 * 691 * mode SWOUT : schedule out everything 692 * mode SWIN : schedule in based on cgroup for next 693 */ 694 static void perf_cgroup_switch(struct task_struct *task, int mode) 695 { 696 struct perf_cpu_context *cpuctx; 697 struct list_head *list; 698 unsigned long flags; 699 700 /* 701 * Disable interrupts and preemption to avoid this CPU's 702 * cgrp_cpuctx_entry to change under us. 703 */ 704 local_irq_save(flags); 705 706 list = this_cpu_ptr(&cgrp_cpuctx_list); 707 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) { 708 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0); 709 710 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 711 perf_pmu_disable(cpuctx->ctx.pmu); 712 713 if (mode & PERF_CGROUP_SWOUT) { 714 cpu_ctx_sched_out(cpuctx, EVENT_ALL); 715 /* 716 * must not be done before ctxswout due 717 * to event_filter_match() in event_sched_out() 718 */ 719 cpuctx->cgrp = NULL; 720 } 721 722 if (mode & PERF_CGROUP_SWIN) { 723 WARN_ON_ONCE(cpuctx->cgrp); 724 /* 725 * set cgrp before ctxsw in to allow 726 * event_filter_match() to not have to pass 727 * task around 728 * we pass the cpuctx->ctx to perf_cgroup_from_task() 729 * because cgorup events are only per-cpu 730 */ 731 cpuctx->cgrp = perf_cgroup_from_task(task, 732 &cpuctx->ctx); 733 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task); 734 } 735 perf_pmu_enable(cpuctx->ctx.pmu); 736 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 737 } 738 739 local_irq_restore(flags); 740 } 741 742 static inline void perf_cgroup_sched_out(struct task_struct *task, 743 struct task_struct *next) 744 { 745 struct perf_cgroup *cgrp1; 746 struct perf_cgroup *cgrp2 = NULL; 747 748 rcu_read_lock(); 749 /* 750 * we come here when we know perf_cgroup_events > 0 751 * we do not need to pass the ctx here because we know 752 * we are holding the rcu lock 753 */ 754 cgrp1 = perf_cgroup_from_task(task, NULL); 755 cgrp2 = perf_cgroup_from_task(next, NULL); 756 757 /* 758 * only schedule out current cgroup events if we know 759 * that we are switching to a different cgroup. Otherwise, 760 * do no touch the cgroup events. 761 */ 762 if (cgrp1 != cgrp2) 763 perf_cgroup_switch(task, PERF_CGROUP_SWOUT); 764 765 rcu_read_unlock(); 766 } 767 768 static inline void perf_cgroup_sched_in(struct task_struct *prev, 769 struct task_struct *task) 770 { 771 struct perf_cgroup *cgrp1; 772 struct perf_cgroup *cgrp2 = NULL; 773 774 rcu_read_lock(); 775 /* 776 * we come here when we know perf_cgroup_events > 0 777 * we do not need to pass the ctx here because we know 778 * we are holding the rcu lock 779 */ 780 cgrp1 = perf_cgroup_from_task(task, NULL); 781 cgrp2 = perf_cgroup_from_task(prev, NULL); 782 783 /* 784 * only need to schedule in cgroup events if we are changing 785 * cgroup during ctxsw. Cgroup events were not scheduled 786 * out of ctxsw out if that was not the case. 787 */ 788 if (cgrp1 != cgrp2) 789 perf_cgroup_switch(task, PERF_CGROUP_SWIN); 790 791 rcu_read_unlock(); 792 } 793 794 static inline int perf_cgroup_connect(int fd, struct perf_event *event, 795 struct perf_event_attr *attr, 796 struct perf_event *group_leader) 797 { 798 struct perf_cgroup *cgrp; 799 struct cgroup_subsys_state *css; 800 struct fd f = fdget(fd); 801 int ret = 0; 802 803 if (!f.file) 804 return -EBADF; 805 806 css = css_tryget_online_from_dir(f.file->f_path.dentry, 807 &perf_event_cgrp_subsys); 808 if (IS_ERR(css)) { 809 ret = PTR_ERR(css); 810 goto out; 811 } 812 813 cgrp = container_of(css, struct perf_cgroup, css); 814 event->cgrp = cgrp; 815 816 /* 817 * all events in a group must monitor 818 * the same cgroup because a task belongs 819 * to only one perf cgroup at a time 820 */ 821 if (group_leader && group_leader->cgrp != cgrp) { 822 perf_detach_cgroup(event); 823 ret = -EINVAL; 824 } 825 out: 826 fdput(f); 827 return ret; 828 } 829 830 static inline void 831 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) 832 { 833 struct perf_cgroup_info *t; 834 t = per_cpu_ptr(event->cgrp->info, event->cpu); 835 event->shadow_ctx_time = now - t->timestamp; 836 } 837 838 static inline void 839 perf_cgroup_defer_enabled(struct perf_event *event) 840 { 841 /* 842 * when the current task's perf cgroup does not match 843 * the event's, we need to remember to call the 844 * perf_mark_enable() function the first time a task with 845 * a matching perf cgroup is scheduled in. 846 */ 847 if (is_cgroup_event(event) && !perf_cgroup_match(event)) 848 event->cgrp_defer_enabled = 1; 849 } 850 851 static inline void 852 perf_cgroup_mark_enabled(struct perf_event *event, 853 struct perf_event_context *ctx) 854 { 855 struct perf_event *sub; 856 u64 tstamp = perf_event_time(event); 857 858 if (!event->cgrp_defer_enabled) 859 return; 860 861 event->cgrp_defer_enabled = 0; 862 863 event->tstamp_enabled = tstamp - event->total_time_enabled; 864 list_for_each_entry(sub, &event->sibling_list, group_entry) { 865 if (sub->state >= PERF_EVENT_STATE_INACTIVE) { 866 sub->tstamp_enabled = tstamp - sub->total_time_enabled; 867 sub->cgrp_defer_enabled = 0; 868 } 869 } 870 } 871 872 /* 873 * Update cpuctx->cgrp so that it is set when first cgroup event is added and 874 * cleared when last cgroup event is removed. 875 */ 876 static inline void 877 list_update_cgroup_event(struct perf_event *event, 878 struct perf_event_context *ctx, bool add) 879 { 880 struct perf_cpu_context *cpuctx; 881 struct list_head *cpuctx_entry; 882 883 if (!is_cgroup_event(event)) 884 return; 885 886 if (add && ctx->nr_cgroups++) 887 return; 888 else if (!add && --ctx->nr_cgroups) 889 return; 890 /* 891 * Because cgroup events are always per-cpu events, 892 * this will always be called from the right CPU. 893 */ 894 cpuctx = __get_cpu_context(ctx); 895 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry; 896 /* cpuctx->cgrp is NULL unless a cgroup event is active in this CPU .*/ 897 if (add) { 898 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list)); 899 if (perf_cgroup_from_task(current, ctx) == event->cgrp) 900 cpuctx->cgrp = event->cgrp; 901 } else { 902 list_del(cpuctx_entry); 903 cpuctx->cgrp = NULL; 904 } 905 } 906 907 #else /* !CONFIG_CGROUP_PERF */ 908 909 static inline bool 910 perf_cgroup_match(struct perf_event *event) 911 { 912 return true; 913 } 914 915 static inline void perf_detach_cgroup(struct perf_event *event) 916 {} 917 918 static inline int is_cgroup_event(struct perf_event *event) 919 { 920 return 0; 921 } 922 923 static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event) 924 { 925 return 0; 926 } 927 928 static inline void update_cgrp_time_from_event(struct perf_event *event) 929 { 930 } 931 932 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) 933 { 934 } 935 936 static inline void perf_cgroup_sched_out(struct task_struct *task, 937 struct task_struct *next) 938 { 939 } 940 941 static inline void perf_cgroup_sched_in(struct task_struct *prev, 942 struct task_struct *task) 943 { 944 } 945 946 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event, 947 struct perf_event_attr *attr, 948 struct perf_event *group_leader) 949 { 950 return -EINVAL; 951 } 952 953 static inline void 954 perf_cgroup_set_timestamp(struct task_struct *task, 955 struct perf_event_context *ctx) 956 { 957 } 958 959 void 960 perf_cgroup_switch(struct task_struct *task, struct task_struct *next) 961 { 962 } 963 964 static inline void 965 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) 966 { 967 } 968 969 static inline u64 perf_cgroup_event_time(struct perf_event *event) 970 { 971 return 0; 972 } 973 974 static inline void 975 perf_cgroup_defer_enabled(struct perf_event *event) 976 { 977 } 978 979 static inline void 980 perf_cgroup_mark_enabled(struct perf_event *event, 981 struct perf_event_context *ctx) 982 { 983 } 984 985 static inline void 986 list_update_cgroup_event(struct perf_event *event, 987 struct perf_event_context *ctx, bool add) 988 { 989 } 990 991 #endif 992 993 /* 994 * set default to be dependent on timer tick just 995 * like original code 996 */ 997 #define PERF_CPU_HRTIMER (1000 / HZ) 998 /* 999 * function must be called with interrupts disbled 1000 */ 1001 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr) 1002 { 1003 struct perf_cpu_context *cpuctx; 1004 int rotations = 0; 1005 1006 WARN_ON(!irqs_disabled()); 1007 1008 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer); 1009 rotations = perf_rotate_context(cpuctx); 1010 1011 raw_spin_lock(&cpuctx->hrtimer_lock); 1012 if (rotations) 1013 hrtimer_forward_now(hr, cpuctx->hrtimer_interval); 1014 else 1015 cpuctx->hrtimer_active = 0; 1016 raw_spin_unlock(&cpuctx->hrtimer_lock); 1017 1018 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART; 1019 } 1020 1021 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu) 1022 { 1023 struct hrtimer *timer = &cpuctx->hrtimer; 1024 struct pmu *pmu = cpuctx->ctx.pmu; 1025 u64 interval; 1026 1027 /* no multiplexing needed for SW PMU */ 1028 if (pmu->task_ctx_nr == perf_sw_context) 1029 return; 1030 1031 /* 1032 * check default is sane, if not set then force to 1033 * default interval (1/tick) 1034 */ 1035 interval = pmu->hrtimer_interval_ms; 1036 if (interval < 1) 1037 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER; 1038 1039 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval); 1040 1041 raw_spin_lock_init(&cpuctx->hrtimer_lock); 1042 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED); 1043 timer->function = perf_mux_hrtimer_handler; 1044 } 1045 1046 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx) 1047 { 1048 struct hrtimer *timer = &cpuctx->hrtimer; 1049 struct pmu *pmu = cpuctx->ctx.pmu; 1050 unsigned long flags; 1051 1052 /* not for SW PMU */ 1053 if (pmu->task_ctx_nr == perf_sw_context) 1054 return 0; 1055 1056 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags); 1057 if (!cpuctx->hrtimer_active) { 1058 cpuctx->hrtimer_active = 1; 1059 hrtimer_forward_now(timer, cpuctx->hrtimer_interval); 1060 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED); 1061 } 1062 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags); 1063 1064 return 0; 1065 } 1066 1067 void perf_pmu_disable(struct pmu *pmu) 1068 { 1069 int *count = this_cpu_ptr(pmu->pmu_disable_count); 1070 if (!(*count)++) 1071 pmu->pmu_disable(pmu); 1072 } 1073 1074 void perf_pmu_enable(struct pmu *pmu) 1075 { 1076 int *count = this_cpu_ptr(pmu->pmu_disable_count); 1077 if (!--(*count)) 1078 pmu->pmu_enable(pmu); 1079 } 1080 1081 static DEFINE_PER_CPU(struct list_head, active_ctx_list); 1082 1083 /* 1084 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and 1085 * perf_event_task_tick() are fully serialized because they're strictly cpu 1086 * affine and perf_event_ctx{activate,deactivate} are called with IRQs 1087 * disabled, while perf_event_task_tick is called from IRQ context. 1088 */ 1089 static void perf_event_ctx_activate(struct perf_event_context *ctx) 1090 { 1091 struct list_head *head = this_cpu_ptr(&active_ctx_list); 1092 1093 WARN_ON(!irqs_disabled()); 1094 1095 WARN_ON(!list_empty(&ctx->active_ctx_list)); 1096 1097 list_add(&ctx->active_ctx_list, head); 1098 } 1099 1100 static void perf_event_ctx_deactivate(struct perf_event_context *ctx) 1101 { 1102 WARN_ON(!irqs_disabled()); 1103 1104 WARN_ON(list_empty(&ctx->active_ctx_list)); 1105 1106 list_del_init(&ctx->active_ctx_list); 1107 } 1108 1109 static void get_ctx(struct perf_event_context *ctx) 1110 { 1111 WARN_ON(!atomic_inc_not_zero(&ctx->refcount)); 1112 } 1113 1114 static void free_ctx(struct rcu_head *head) 1115 { 1116 struct perf_event_context *ctx; 1117 1118 ctx = container_of(head, struct perf_event_context, rcu_head); 1119 kfree(ctx->task_ctx_data); 1120 kfree(ctx); 1121 } 1122 1123 static void put_ctx(struct perf_event_context *ctx) 1124 { 1125 if (atomic_dec_and_test(&ctx->refcount)) { 1126 if (ctx->parent_ctx) 1127 put_ctx(ctx->parent_ctx); 1128 if (ctx->task && ctx->task != TASK_TOMBSTONE) 1129 put_task_struct(ctx->task); 1130 call_rcu(&ctx->rcu_head, free_ctx); 1131 } 1132 } 1133 1134 /* 1135 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and 1136 * perf_pmu_migrate_context() we need some magic. 1137 * 1138 * Those places that change perf_event::ctx will hold both 1139 * perf_event_ctx::mutex of the 'old' and 'new' ctx value. 1140 * 1141 * Lock ordering is by mutex address. There are two other sites where 1142 * perf_event_context::mutex nests and those are: 1143 * 1144 * - perf_event_exit_task_context() [ child , 0 ] 1145 * perf_event_exit_event() 1146 * put_event() [ parent, 1 ] 1147 * 1148 * - perf_event_init_context() [ parent, 0 ] 1149 * inherit_task_group() 1150 * inherit_group() 1151 * inherit_event() 1152 * perf_event_alloc() 1153 * perf_init_event() 1154 * perf_try_init_event() [ child , 1 ] 1155 * 1156 * While it appears there is an obvious deadlock here -- the parent and child 1157 * nesting levels are inverted between the two. This is in fact safe because 1158 * life-time rules separate them. That is an exiting task cannot fork, and a 1159 * spawning task cannot (yet) exit. 1160 * 1161 * But remember that that these are parent<->child context relations, and 1162 * migration does not affect children, therefore these two orderings should not 1163 * interact. 1164 * 1165 * The change in perf_event::ctx does not affect children (as claimed above) 1166 * because the sys_perf_event_open() case will install a new event and break 1167 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only 1168 * concerned with cpuctx and that doesn't have children. 1169 * 1170 * The places that change perf_event::ctx will issue: 1171 * 1172 * perf_remove_from_context(); 1173 * synchronize_rcu(); 1174 * perf_install_in_context(); 1175 * 1176 * to affect the change. The remove_from_context() + synchronize_rcu() should 1177 * quiesce the event, after which we can install it in the new location. This 1178 * means that only external vectors (perf_fops, prctl) can perturb the event 1179 * while in transit. Therefore all such accessors should also acquire 1180 * perf_event_context::mutex to serialize against this. 1181 * 1182 * However; because event->ctx can change while we're waiting to acquire 1183 * ctx->mutex we must be careful and use the below perf_event_ctx_lock() 1184 * function. 1185 * 1186 * Lock order: 1187 * cred_guard_mutex 1188 * task_struct::perf_event_mutex 1189 * perf_event_context::mutex 1190 * perf_event::child_mutex; 1191 * perf_event_context::lock 1192 * perf_event::mmap_mutex 1193 * mmap_sem 1194 */ 1195 static struct perf_event_context * 1196 perf_event_ctx_lock_nested(struct perf_event *event, int nesting) 1197 { 1198 struct perf_event_context *ctx; 1199 1200 again: 1201 rcu_read_lock(); 1202 ctx = ACCESS_ONCE(event->ctx); 1203 if (!atomic_inc_not_zero(&ctx->refcount)) { 1204 rcu_read_unlock(); 1205 goto again; 1206 } 1207 rcu_read_unlock(); 1208 1209 mutex_lock_nested(&ctx->mutex, nesting); 1210 if (event->ctx != ctx) { 1211 mutex_unlock(&ctx->mutex); 1212 put_ctx(ctx); 1213 goto again; 1214 } 1215 1216 return ctx; 1217 } 1218 1219 static inline struct perf_event_context * 1220 perf_event_ctx_lock(struct perf_event *event) 1221 { 1222 return perf_event_ctx_lock_nested(event, 0); 1223 } 1224 1225 static void perf_event_ctx_unlock(struct perf_event *event, 1226 struct perf_event_context *ctx) 1227 { 1228 mutex_unlock(&ctx->mutex); 1229 put_ctx(ctx); 1230 } 1231 1232 /* 1233 * This must be done under the ctx->lock, such as to serialize against 1234 * context_equiv(), therefore we cannot call put_ctx() since that might end up 1235 * calling scheduler related locks and ctx->lock nests inside those. 1236 */ 1237 static __must_check struct perf_event_context * 1238 unclone_ctx(struct perf_event_context *ctx) 1239 { 1240 struct perf_event_context *parent_ctx = ctx->parent_ctx; 1241 1242 lockdep_assert_held(&ctx->lock); 1243 1244 if (parent_ctx) 1245 ctx->parent_ctx = NULL; 1246 ctx->generation++; 1247 1248 return parent_ctx; 1249 } 1250 1251 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) 1252 { 1253 /* 1254 * only top level events have the pid namespace they were created in 1255 */ 1256 if (event->parent) 1257 event = event->parent; 1258 1259 return task_tgid_nr_ns(p, event->ns); 1260 } 1261 1262 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) 1263 { 1264 /* 1265 * only top level events have the pid namespace they were created in 1266 */ 1267 if (event->parent) 1268 event = event->parent; 1269 1270 return task_pid_nr_ns(p, event->ns); 1271 } 1272 1273 /* 1274 * If we inherit events we want to return the parent event id 1275 * to userspace. 1276 */ 1277 static u64 primary_event_id(struct perf_event *event) 1278 { 1279 u64 id = event->id; 1280 1281 if (event->parent) 1282 id = event->parent->id; 1283 1284 return id; 1285 } 1286 1287 /* 1288 * Get the perf_event_context for a task and lock it. 1289 * 1290 * This has to cope with with the fact that until it is locked, 1291 * the context could get moved to another task. 1292 */ 1293 static struct perf_event_context * 1294 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags) 1295 { 1296 struct perf_event_context *ctx; 1297 1298 retry: 1299 /* 1300 * One of the few rules of preemptible RCU is that one cannot do 1301 * rcu_read_unlock() while holding a scheduler (or nested) lock when 1302 * part of the read side critical section was irqs-enabled -- see 1303 * rcu_read_unlock_special(). 1304 * 1305 * Since ctx->lock nests under rq->lock we must ensure the entire read 1306 * side critical section has interrupts disabled. 1307 */ 1308 local_irq_save(*flags); 1309 rcu_read_lock(); 1310 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]); 1311 if (ctx) { 1312 /* 1313 * If this context is a clone of another, it might 1314 * get swapped for another underneath us by 1315 * perf_event_task_sched_out, though the 1316 * rcu_read_lock() protects us from any context 1317 * getting freed. Lock the context and check if it 1318 * got swapped before we could get the lock, and retry 1319 * if so. If we locked the right context, then it 1320 * can't get swapped on us any more. 1321 */ 1322 raw_spin_lock(&ctx->lock); 1323 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) { 1324 raw_spin_unlock(&ctx->lock); 1325 rcu_read_unlock(); 1326 local_irq_restore(*flags); 1327 goto retry; 1328 } 1329 1330 if (ctx->task == TASK_TOMBSTONE || 1331 !atomic_inc_not_zero(&ctx->refcount)) { 1332 raw_spin_unlock(&ctx->lock); 1333 ctx = NULL; 1334 } else { 1335 WARN_ON_ONCE(ctx->task != task); 1336 } 1337 } 1338 rcu_read_unlock(); 1339 if (!ctx) 1340 local_irq_restore(*flags); 1341 return ctx; 1342 } 1343 1344 /* 1345 * Get the context for a task and increment its pin_count so it 1346 * can't get swapped to another task. This also increments its 1347 * reference count so that the context can't get freed. 1348 */ 1349 static struct perf_event_context * 1350 perf_pin_task_context(struct task_struct *task, int ctxn) 1351 { 1352 struct perf_event_context *ctx; 1353 unsigned long flags; 1354 1355 ctx = perf_lock_task_context(task, ctxn, &flags); 1356 if (ctx) { 1357 ++ctx->pin_count; 1358 raw_spin_unlock_irqrestore(&ctx->lock, flags); 1359 } 1360 return ctx; 1361 } 1362 1363 static void perf_unpin_context(struct perf_event_context *ctx) 1364 { 1365 unsigned long flags; 1366 1367 raw_spin_lock_irqsave(&ctx->lock, flags); 1368 --ctx->pin_count; 1369 raw_spin_unlock_irqrestore(&ctx->lock, flags); 1370 } 1371 1372 /* 1373 * Update the record of the current time in a context. 1374 */ 1375 static void update_context_time(struct perf_event_context *ctx) 1376 { 1377 u64 now = perf_clock(); 1378 1379 ctx->time += now - ctx->timestamp; 1380 ctx->timestamp = now; 1381 } 1382 1383 static u64 perf_event_time(struct perf_event *event) 1384 { 1385 struct perf_event_context *ctx = event->ctx; 1386 1387 if (is_cgroup_event(event)) 1388 return perf_cgroup_event_time(event); 1389 1390 return ctx ? ctx->time : 0; 1391 } 1392 1393 /* 1394 * Update the total_time_enabled and total_time_running fields for a event. 1395 */ 1396 static void update_event_times(struct perf_event *event) 1397 { 1398 struct perf_event_context *ctx = event->ctx; 1399 u64 run_end; 1400 1401 lockdep_assert_held(&ctx->lock); 1402 1403 if (event->state < PERF_EVENT_STATE_INACTIVE || 1404 event->group_leader->state < PERF_EVENT_STATE_INACTIVE) 1405 return; 1406 1407 /* 1408 * in cgroup mode, time_enabled represents 1409 * the time the event was enabled AND active 1410 * tasks were in the monitored cgroup. This is 1411 * independent of the activity of the context as 1412 * there may be a mix of cgroup and non-cgroup events. 1413 * 1414 * That is why we treat cgroup events differently 1415 * here. 1416 */ 1417 if (is_cgroup_event(event)) 1418 run_end = perf_cgroup_event_time(event); 1419 else if (ctx->is_active) 1420 run_end = ctx->time; 1421 else 1422 run_end = event->tstamp_stopped; 1423 1424 event->total_time_enabled = run_end - event->tstamp_enabled; 1425 1426 if (event->state == PERF_EVENT_STATE_INACTIVE) 1427 run_end = event->tstamp_stopped; 1428 else 1429 run_end = perf_event_time(event); 1430 1431 event->total_time_running = run_end - event->tstamp_running; 1432 1433 } 1434 1435 /* 1436 * Update total_time_enabled and total_time_running for all events in a group. 1437 */ 1438 static void update_group_times(struct perf_event *leader) 1439 { 1440 struct perf_event *event; 1441 1442 update_event_times(leader); 1443 list_for_each_entry(event, &leader->sibling_list, group_entry) 1444 update_event_times(event); 1445 } 1446 1447 static enum event_type_t get_event_type(struct perf_event *event) 1448 { 1449 struct perf_event_context *ctx = event->ctx; 1450 enum event_type_t event_type; 1451 1452 lockdep_assert_held(&ctx->lock); 1453 1454 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE; 1455 if (!ctx->task) 1456 event_type |= EVENT_CPU; 1457 1458 return event_type; 1459 } 1460 1461 static struct list_head * 1462 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx) 1463 { 1464 if (event->attr.pinned) 1465 return &ctx->pinned_groups; 1466 else 1467 return &ctx->flexible_groups; 1468 } 1469 1470 /* 1471 * Add a event from the lists for its context. 1472 * Must be called with ctx->mutex and ctx->lock held. 1473 */ 1474 static void 1475 list_add_event(struct perf_event *event, struct perf_event_context *ctx) 1476 { 1477 lockdep_assert_held(&ctx->lock); 1478 1479 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); 1480 event->attach_state |= PERF_ATTACH_CONTEXT; 1481 1482 /* 1483 * If we're a stand alone event or group leader, we go to the context 1484 * list, group events are kept attached to the group so that 1485 * perf_group_detach can, at all times, locate all siblings. 1486 */ 1487 if (event->group_leader == event) { 1488 struct list_head *list; 1489 1490 event->group_caps = event->event_caps; 1491 1492 list = ctx_group_list(event, ctx); 1493 list_add_tail(&event->group_entry, list); 1494 } 1495 1496 list_update_cgroup_event(event, ctx, true); 1497 1498 list_add_rcu(&event->event_entry, &ctx->event_list); 1499 ctx->nr_events++; 1500 if (event->attr.inherit_stat) 1501 ctx->nr_stat++; 1502 1503 ctx->generation++; 1504 } 1505 1506 /* 1507 * Initialize event state based on the perf_event_attr::disabled. 1508 */ 1509 static inline void perf_event__state_init(struct perf_event *event) 1510 { 1511 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF : 1512 PERF_EVENT_STATE_INACTIVE; 1513 } 1514 1515 static void __perf_event_read_size(struct perf_event *event, int nr_siblings) 1516 { 1517 int entry = sizeof(u64); /* value */ 1518 int size = 0; 1519 int nr = 1; 1520 1521 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 1522 size += sizeof(u64); 1523 1524 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 1525 size += sizeof(u64); 1526 1527 if (event->attr.read_format & PERF_FORMAT_ID) 1528 entry += sizeof(u64); 1529 1530 if (event->attr.read_format & PERF_FORMAT_GROUP) { 1531 nr += nr_siblings; 1532 size += sizeof(u64); 1533 } 1534 1535 size += entry * nr; 1536 event->read_size = size; 1537 } 1538 1539 static void __perf_event_header_size(struct perf_event *event, u64 sample_type) 1540 { 1541 struct perf_sample_data *data; 1542 u16 size = 0; 1543 1544 if (sample_type & PERF_SAMPLE_IP) 1545 size += sizeof(data->ip); 1546 1547 if (sample_type & PERF_SAMPLE_ADDR) 1548 size += sizeof(data->addr); 1549 1550 if (sample_type & PERF_SAMPLE_PERIOD) 1551 size += sizeof(data->period); 1552 1553 if (sample_type & PERF_SAMPLE_WEIGHT) 1554 size += sizeof(data->weight); 1555 1556 if (sample_type & PERF_SAMPLE_READ) 1557 size += event->read_size; 1558 1559 if (sample_type & PERF_SAMPLE_DATA_SRC) 1560 size += sizeof(data->data_src.val); 1561 1562 if (sample_type & PERF_SAMPLE_TRANSACTION) 1563 size += sizeof(data->txn); 1564 1565 event->header_size = size; 1566 } 1567 1568 /* 1569 * Called at perf_event creation and when events are attached/detached from a 1570 * group. 1571 */ 1572 static void perf_event__header_size(struct perf_event *event) 1573 { 1574 __perf_event_read_size(event, 1575 event->group_leader->nr_siblings); 1576 __perf_event_header_size(event, event->attr.sample_type); 1577 } 1578 1579 static void perf_event__id_header_size(struct perf_event *event) 1580 { 1581 struct perf_sample_data *data; 1582 u64 sample_type = event->attr.sample_type; 1583 u16 size = 0; 1584 1585 if (sample_type & PERF_SAMPLE_TID) 1586 size += sizeof(data->tid_entry); 1587 1588 if (sample_type & PERF_SAMPLE_TIME) 1589 size += sizeof(data->time); 1590 1591 if (sample_type & PERF_SAMPLE_IDENTIFIER) 1592 size += sizeof(data->id); 1593 1594 if (sample_type & PERF_SAMPLE_ID) 1595 size += sizeof(data->id); 1596 1597 if (sample_type & PERF_SAMPLE_STREAM_ID) 1598 size += sizeof(data->stream_id); 1599 1600 if (sample_type & PERF_SAMPLE_CPU) 1601 size += sizeof(data->cpu_entry); 1602 1603 event->id_header_size = size; 1604 } 1605 1606 static bool perf_event_validate_size(struct perf_event *event) 1607 { 1608 /* 1609 * The values computed here will be over-written when we actually 1610 * attach the event. 1611 */ 1612 __perf_event_read_size(event, event->group_leader->nr_siblings + 1); 1613 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ); 1614 perf_event__id_header_size(event); 1615 1616 /* 1617 * Sum the lot; should not exceed the 64k limit we have on records. 1618 * Conservative limit to allow for callchains and other variable fields. 1619 */ 1620 if (event->read_size + event->header_size + 1621 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024) 1622 return false; 1623 1624 return true; 1625 } 1626 1627 static void perf_group_attach(struct perf_event *event) 1628 { 1629 struct perf_event *group_leader = event->group_leader, *pos; 1630 1631 lockdep_assert_held(&event->ctx->lock); 1632 1633 /* 1634 * We can have double attach due to group movement in perf_event_open. 1635 */ 1636 if (event->attach_state & PERF_ATTACH_GROUP) 1637 return; 1638 1639 event->attach_state |= PERF_ATTACH_GROUP; 1640 1641 if (group_leader == event) 1642 return; 1643 1644 WARN_ON_ONCE(group_leader->ctx != event->ctx); 1645 1646 group_leader->group_caps &= event->event_caps; 1647 1648 list_add_tail(&event->group_entry, &group_leader->sibling_list); 1649 group_leader->nr_siblings++; 1650 1651 perf_event__header_size(group_leader); 1652 1653 list_for_each_entry(pos, &group_leader->sibling_list, group_entry) 1654 perf_event__header_size(pos); 1655 } 1656 1657 /* 1658 * Remove a event from the lists for its context. 1659 * Must be called with ctx->mutex and ctx->lock held. 1660 */ 1661 static void 1662 list_del_event(struct perf_event *event, struct perf_event_context *ctx) 1663 { 1664 WARN_ON_ONCE(event->ctx != ctx); 1665 lockdep_assert_held(&ctx->lock); 1666 1667 /* 1668 * We can have double detach due to exit/hot-unplug + close. 1669 */ 1670 if (!(event->attach_state & PERF_ATTACH_CONTEXT)) 1671 return; 1672 1673 event->attach_state &= ~PERF_ATTACH_CONTEXT; 1674 1675 list_update_cgroup_event(event, ctx, false); 1676 1677 ctx->nr_events--; 1678 if (event->attr.inherit_stat) 1679 ctx->nr_stat--; 1680 1681 list_del_rcu(&event->event_entry); 1682 1683 if (event->group_leader == event) 1684 list_del_init(&event->group_entry); 1685 1686 update_group_times(event); 1687 1688 /* 1689 * If event was in error state, then keep it 1690 * that way, otherwise bogus counts will be 1691 * returned on read(). The only way to get out 1692 * of error state is by explicit re-enabling 1693 * of the event 1694 */ 1695 if (event->state > PERF_EVENT_STATE_OFF) 1696 event->state = PERF_EVENT_STATE_OFF; 1697 1698 ctx->generation++; 1699 } 1700 1701 static void perf_group_detach(struct perf_event *event) 1702 { 1703 struct perf_event *sibling, *tmp; 1704 struct list_head *list = NULL; 1705 1706 lockdep_assert_held(&event->ctx->lock); 1707 1708 /* 1709 * We can have double detach due to exit/hot-unplug + close. 1710 */ 1711 if (!(event->attach_state & PERF_ATTACH_GROUP)) 1712 return; 1713 1714 event->attach_state &= ~PERF_ATTACH_GROUP; 1715 1716 /* 1717 * If this is a sibling, remove it from its group. 1718 */ 1719 if (event->group_leader != event) { 1720 list_del_init(&event->group_entry); 1721 event->group_leader->nr_siblings--; 1722 goto out; 1723 } 1724 1725 if (!list_empty(&event->group_entry)) 1726 list = &event->group_entry; 1727 1728 /* 1729 * If this was a group event with sibling events then 1730 * upgrade the siblings to singleton events by adding them 1731 * to whatever list we are on. 1732 */ 1733 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) { 1734 if (list) 1735 list_move_tail(&sibling->group_entry, list); 1736 sibling->group_leader = sibling; 1737 1738 /* Inherit group flags from the previous leader */ 1739 sibling->group_caps = event->group_caps; 1740 1741 WARN_ON_ONCE(sibling->ctx != event->ctx); 1742 } 1743 1744 out: 1745 perf_event__header_size(event->group_leader); 1746 1747 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry) 1748 perf_event__header_size(tmp); 1749 } 1750 1751 static bool is_orphaned_event(struct perf_event *event) 1752 { 1753 return event->state == PERF_EVENT_STATE_DEAD; 1754 } 1755 1756 static inline int __pmu_filter_match(struct perf_event *event) 1757 { 1758 struct pmu *pmu = event->pmu; 1759 return pmu->filter_match ? pmu->filter_match(event) : 1; 1760 } 1761 1762 /* 1763 * Check whether we should attempt to schedule an event group based on 1764 * PMU-specific filtering. An event group can consist of HW and SW events, 1765 * potentially with a SW leader, so we must check all the filters, to 1766 * determine whether a group is schedulable: 1767 */ 1768 static inline int pmu_filter_match(struct perf_event *event) 1769 { 1770 struct perf_event *child; 1771 1772 if (!__pmu_filter_match(event)) 1773 return 0; 1774 1775 list_for_each_entry(child, &event->sibling_list, group_entry) { 1776 if (!__pmu_filter_match(child)) 1777 return 0; 1778 } 1779 1780 return 1; 1781 } 1782 1783 static inline int 1784 event_filter_match(struct perf_event *event) 1785 { 1786 return (event->cpu == -1 || event->cpu == smp_processor_id()) && 1787 perf_cgroup_match(event) && pmu_filter_match(event); 1788 } 1789 1790 static void 1791 event_sched_out(struct perf_event *event, 1792 struct perf_cpu_context *cpuctx, 1793 struct perf_event_context *ctx) 1794 { 1795 u64 tstamp = perf_event_time(event); 1796 u64 delta; 1797 1798 WARN_ON_ONCE(event->ctx != ctx); 1799 lockdep_assert_held(&ctx->lock); 1800 1801 /* 1802 * An event which could not be activated because of 1803 * filter mismatch still needs to have its timings 1804 * maintained, otherwise bogus information is return 1805 * via read() for time_enabled, time_running: 1806 */ 1807 if (event->state == PERF_EVENT_STATE_INACTIVE && 1808 !event_filter_match(event)) { 1809 delta = tstamp - event->tstamp_stopped; 1810 event->tstamp_running += delta; 1811 event->tstamp_stopped = tstamp; 1812 } 1813 1814 if (event->state != PERF_EVENT_STATE_ACTIVE) 1815 return; 1816 1817 perf_pmu_disable(event->pmu); 1818 1819 event->tstamp_stopped = tstamp; 1820 event->pmu->del(event, 0); 1821 event->oncpu = -1; 1822 event->state = PERF_EVENT_STATE_INACTIVE; 1823 if (event->pending_disable) { 1824 event->pending_disable = 0; 1825 event->state = PERF_EVENT_STATE_OFF; 1826 } 1827 1828 if (!is_software_event(event)) 1829 cpuctx->active_oncpu--; 1830 if (!--ctx->nr_active) 1831 perf_event_ctx_deactivate(ctx); 1832 if (event->attr.freq && event->attr.sample_freq) 1833 ctx->nr_freq--; 1834 if (event->attr.exclusive || !cpuctx->active_oncpu) 1835 cpuctx->exclusive = 0; 1836 1837 perf_pmu_enable(event->pmu); 1838 } 1839 1840 static void 1841 group_sched_out(struct perf_event *group_event, 1842 struct perf_cpu_context *cpuctx, 1843 struct perf_event_context *ctx) 1844 { 1845 struct perf_event *event; 1846 int state = group_event->state; 1847 1848 perf_pmu_disable(ctx->pmu); 1849 1850 event_sched_out(group_event, cpuctx, ctx); 1851 1852 /* 1853 * Schedule out siblings (if any): 1854 */ 1855 list_for_each_entry(event, &group_event->sibling_list, group_entry) 1856 event_sched_out(event, cpuctx, ctx); 1857 1858 perf_pmu_enable(ctx->pmu); 1859 1860 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive) 1861 cpuctx->exclusive = 0; 1862 } 1863 1864 #define DETACH_GROUP 0x01UL 1865 1866 /* 1867 * Cross CPU call to remove a performance event 1868 * 1869 * We disable the event on the hardware level first. After that we 1870 * remove it from the context list. 1871 */ 1872 static void 1873 __perf_remove_from_context(struct perf_event *event, 1874 struct perf_cpu_context *cpuctx, 1875 struct perf_event_context *ctx, 1876 void *info) 1877 { 1878 unsigned long flags = (unsigned long)info; 1879 1880 event_sched_out(event, cpuctx, ctx); 1881 if (flags & DETACH_GROUP) 1882 perf_group_detach(event); 1883 list_del_event(event, ctx); 1884 1885 if (!ctx->nr_events && ctx->is_active) { 1886 ctx->is_active = 0; 1887 if (ctx->task) { 1888 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 1889 cpuctx->task_ctx = NULL; 1890 } 1891 } 1892 } 1893 1894 /* 1895 * Remove the event from a task's (or a CPU's) list of events. 1896 * 1897 * If event->ctx is a cloned context, callers must make sure that 1898 * every task struct that event->ctx->task could possibly point to 1899 * remains valid. This is OK when called from perf_release since 1900 * that only calls us on the top-level context, which can't be a clone. 1901 * When called from perf_event_exit_task, it's OK because the 1902 * context has been detached from its task. 1903 */ 1904 static void perf_remove_from_context(struct perf_event *event, unsigned long flags) 1905 { 1906 struct perf_event_context *ctx = event->ctx; 1907 1908 lockdep_assert_held(&ctx->mutex); 1909 1910 event_function_call(event, __perf_remove_from_context, (void *)flags); 1911 1912 /* 1913 * The above event_function_call() can NO-OP when it hits 1914 * TASK_TOMBSTONE. In that case we must already have been detached 1915 * from the context (by perf_event_exit_event()) but the grouping 1916 * might still be in-tact. 1917 */ 1918 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); 1919 if ((flags & DETACH_GROUP) && 1920 (event->attach_state & PERF_ATTACH_GROUP)) { 1921 /* 1922 * Since in that case we cannot possibly be scheduled, simply 1923 * detach now. 1924 */ 1925 raw_spin_lock_irq(&ctx->lock); 1926 perf_group_detach(event); 1927 raw_spin_unlock_irq(&ctx->lock); 1928 } 1929 } 1930 1931 /* 1932 * Cross CPU call to disable a performance event 1933 */ 1934 static void __perf_event_disable(struct perf_event *event, 1935 struct perf_cpu_context *cpuctx, 1936 struct perf_event_context *ctx, 1937 void *info) 1938 { 1939 if (event->state < PERF_EVENT_STATE_INACTIVE) 1940 return; 1941 1942 update_context_time(ctx); 1943 update_cgrp_time_from_event(event); 1944 update_group_times(event); 1945 if (event == event->group_leader) 1946 group_sched_out(event, cpuctx, ctx); 1947 else 1948 event_sched_out(event, cpuctx, ctx); 1949 event->state = PERF_EVENT_STATE_OFF; 1950 } 1951 1952 /* 1953 * Disable a event. 1954 * 1955 * If event->ctx is a cloned context, callers must make sure that 1956 * every task struct that event->ctx->task could possibly point to 1957 * remains valid. This condition is satisifed when called through 1958 * perf_event_for_each_child or perf_event_for_each because they 1959 * hold the top-level event's child_mutex, so any descendant that 1960 * goes to exit will block in perf_event_exit_event(). 1961 * 1962 * When called from perf_pending_event it's OK because event->ctx 1963 * is the current context on this CPU and preemption is disabled, 1964 * hence we can't get into perf_event_task_sched_out for this context. 1965 */ 1966 static void _perf_event_disable(struct perf_event *event) 1967 { 1968 struct perf_event_context *ctx = event->ctx; 1969 1970 raw_spin_lock_irq(&ctx->lock); 1971 if (event->state <= PERF_EVENT_STATE_OFF) { 1972 raw_spin_unlock_irq(&ctx->lock); 1973 return; 1974 } 1975 raw_spin_unlock_irq(&ctx->lock); 1976 1977 event_function_call(event, __perf_event_disable, NULL); 1978 } 1979 1980 void perf_event_disable_local(struct perf_event *event) 1981 { 1982 event_function_local(event, __perf_event_disable, NULL); 1983 } 1984 1985 /* 1986 * Strictly speaking kernel users cannot create groups and therefore this 1987 * interface does not need the perf_event_ctx_lock() magic. 1988 */ 1989 void perf_event_disable(struct perf_event *event) 1990 { 1991 struct perf_event_context *ctx; 1992 1993 ctx = perf_event_ctx_lock(event); 1994 _perf_event_disable(event); 1995 perf_event_ctx_unlock(event, ctx); 1996 } 1997 EXPORT_SYMBOL_GPL(perf_event_disable); 1998 1999 void perf_event_disable_inatomic(struct perf_event *event) 2000 { 2001 event->pending_disable = 1; 2002 irq_work_queue(&event->pending); 2003 } 2004 2005 static void perf_set_shadow_time(struct perf_event *event, 2006 struct perf_event_context *ctx, 2007 u64 tstamp) 2008 { 2009 /* 2010 * use the correct time source for the time snapshot 2011 * 2012 * We could get by without this by leveraging the 2013 * fact that to get to this function, the caller 2014 * has most likely already called update_context_time() 2015 * and update_cgrp_time_xx() and thus both timestamp 2016 * are identical (or very close). Given that tstamp is, 2017 * already adjusted for cgroup, we could say that: 2018 * tstamp - ctx->timestamp 2019 * is equivalent to 2020 * tstamp - cgrp->timestamp. 2021 * 2022 * Then, in perf_output_read(), the calculation would 2023 * work with no changes because: 2024 * - event is guaranteed scheduled in 2025 * - no scheduled out in between 2026 * - thus the timestamp would be the same 2027 * 2028 * But this is a bit hairy. 2029 * 2030 * So instead, we have an explicit cgroup call to remain 2031 * within the time time source all along. We believe it 2032 * is cleaner and simpler to understand. 2033 */ 2034 if (is_cgroup_event(event)) 2035 perf_cgroup_set_shadow_time(event, tstamp); 2036 else 2037 event->shadow_ctx_time = tstamp - ctx->timestamp; 2038 } 2039 2040 #define MAX_INTERRUPTS (~0ULL) 2041 2042 static void perf_log_throttle(struct perf_event *event, int enable); 2043 static void perf_log_itrace_start(struct perf_event *event); 2044 2045 static int 2046 event_sched_in(struct perf_event *event, 2047 struct perf_cpu_context *cpuctx, 2048 struct perf_event_context *ctx) 2049 { 2050 u64 tstamp = perf_event_time(event); 2051 int ret = 0; 2052 2053 lockdep_assert_held(&ctx->lock); 2054 2055 if (event->state <= PERF_EVENT_STATE_OFF) 2056 return 0; 2057 2058 WRITE_ONCE(event->oncpu, smp_processor_id()); 2059 /* 2060 * Order event::oncpu write to happen before the ACTIVE state 2061 * is visible. 2062 */ 2063 smp_wmb(); 2064 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE); 2065 2066 /* 2067 * Unthrottle events, since we scheduled we might have missed several 2068 * ticks already, also for a heavily scheduling task there is little 2069 * guarantee it'll get a tick in a timely manner. 2070 */ 2071 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) { 2072 perf_log_throttle(event, 1); 2073 event->hw.interrupts = 0; 2074 } 2075 2076 /* 2077 * The new state must be visible before we turn it on in the hardware: 2078 */ 2079 smp_wmb(); 2080 2081 perf_pmu_disable(event->pmu); 2082 2083 perf_set_shadow_time(event, ctx, tstamp); 2084 2085 perf_log_itrace_start(event); 2086 2087 if (event->pmu->add(event, PERF_EF_START)) { 2088 event->state = PERF_EVENT_STATE_INACTIVE; 2089 event->oncpu = -1; 2090 ret = -EAGAIN; 2091 goto out; 2092 } 2093 2094 event->tstamp_running += tstamp - event->tstamp_stopped; 2095 2096 if (!is_software_event(event)) 2097 cpuctx->active_oncpu++; 2098 if (!ctx->nr_active++) 2099 perf_event_ctx_activate(ctx); 2100 if (event->attr.freq && event->attr.sample_freq) 2101 ctx->nr_freq++; 2102 2103 if (event->attr.exclusive) 2104 cpuctx->exclusive = 1; 2105 2106 out: 2107 perf_pmu_enable(event->pmu); 2108 2109 return ret; 2110 } 2111 2112 static int 2113 group_sched_in(struct perf_event *group_event, 2114 struct perf_cpu_context *cpuctx, 2115 struct perf_event_context *ctx) 2116 { 2117 struct perf_event *event, *partial_group = NULL; 2118 struct pmu *pmu = ctx->pmu; 2119 u64 now = ctx->time; 2120 bool simulate = false; 2121 2122 if (group_event->state == PERF_EVENT_STATE_OFF) 2123 return 0; 2124 2125 pmu->start_txn(pmu, PERF_PMU_TXN_ADD); 2126 2127 if (event_sched_in(group_event, cpuctx, ctx)) { 2128 pmu->cancel_txn(pmu); 2129 perf_mux_hrtimer_restart(cpuctx); 2130 return -EAGAIN; 2131 } 2132 2133 /* 2134 * Schedule in siblings as one group (if any): 2135 */ 2136 list_for_each_entry(event, &group_event->sibling_list, group_entry) { 2137 if (event_sched_in(event, cpuctx, ctx)) { 2138 partial_group = event; 2139 goto group_error; 2140 } 2141 } 2142 2143 if (!pmu->commit_txn(pmu)) 2144 return 0; 2145 2146 group_error: 2147 /* 2148 * Groups can be scheduled in as one unit only, so undo any 2149 * partial group before returning: 2150 * The events up to the failed event are scheduled out normally, 2151 * tstamp_stopped will be updated. 2152 * 2153 * The failed events and the remaining siblings need to have 2154 * their timings updated as if they had gone thru event_sched_in() 2155 * and event_sched_out(). This is required to get consistent timings 2156 * across the group. This also takes care of the case where the group 2157 * could never be scheduled by ensuring tstamp_stopped is set to mark 2158 * the time the event was actually stopped, such that time delta 2159 * calculation in update_event_times() is correct. 2160 */ 2161 list_for_each_entry(event, &group_event->sibling_list, group_entry) { 2162 if (event == partial_group) 2163 simulate = true; 2164 2165 if (simulate) { 2166 event->tstamp_running += now - event->tstamp_stopped; 2167 event->tstamp_stopped = now; 2168 } else { 2169 event_sched_out(event, cpuctx, ctx); 2170 } 2171 } 2172 event_sched_out(group_event, cpuctx, ctx); 2173 2174 pmu->cancel_txn(pmu); 2175 2176 perf_mux_hrtimer_restart(cpuctx); 2177 2178 return -EAGAIN; 2179 } 2180 2181 /* 2182 * Work out whether we can put this event group on the CPU now. 2183 */ 2184 static int group_can_go_on(struct perf_event *event, 2185 struct perf_cpu_context *cpuctx, 2186 int can_add_hw) 2187 { 2188 /* 2189 * Groups consisting entirely of software events can always go on. 2190 */ 2191 if (event->group_caps & PERF_EV_CAP_SOFTWARE) 2192 return 1; 2193 /* 2194 * If an exclusive group is already on, no other hardware 2195 * events can go on. 2196 */ 2197 if (cpuctx->exclusive) 2198 return 0; 2199 /* 2200 * If this group is exclusive and there are already 2201 * events on the CPU, it can't go on. 2202 */ 2203 if (event->attr.exclusive && cpuctx->active_oncpu) 2204 return 0; 2205 /* 2206 * Otherwise, try to add it if all previous groups were able 2207 * to go on. 2208 */ 2209 return can_add_hw; 2210 } 2211 2212 static void add_event_to_ctx(struct perf_event *event, 2213 struct perf_event_context *ctx) 2214 { 2215 u64 tstamp = perf_event_time(event); 2216 2217 list_add_event(event, ctx); 2218 perf_group_attach(event); 2219 event->tstamp_enabled = tstamp; 2220 event->tstamp_running = tstamp; 2221 event->tstamp_stopped = tstamp; 2222 } 2223 2224 static void ctx_sched_out(struct perf_event_context *ctx, 2225 struct perf_cpu_context *cpuctx, 2226 enum event_type_t event_type); 2227 static void 2228 ctx_sched_in(struct perf_event_context *ctx, 2229 struct perf_cpu_context *cpuctx, 2230 enum event_type_t event_type, 2231 struct task_struct *task); 2232 2233 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx, 2234 struct perf_event_context *ctx, 2235 enum event_type_t event_type) 2236 { 2237 if (!cpuctx->task_ctx) 2238 return; 2239 2240 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx)) 2241 return; 2242 2243 ctx_sched_out(ctx, cpuctx, event_type); 2244 } 2245 2246 static void perf_event_sched_in(struct perf_cpu_context *cpuctx, 2247 struct perf_event_context *ctx, 2248 struct task_struct *task) 2249 { 2250 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task); 2251 if (ctx) 2252 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task); 2253 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task); 2254 if (ctx) 2255 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task); 2256 } 2257 2258 /* 2259 * We want to maintain the following priority of scheduling: 2260 * - CPU pinned (EVENT_CPU | EVENT_PINNED) 2261 * - task pinned (EVENT_PINNED) 2262 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE) 2263 * - task flexible (EVENT_FLEXIBLE). 2264 * 2265 * In order to avoid unscheduling and scheduling back in everything every 2266 * time an event is added, only do it for the groups of equal priority and 2267 * below. 2268 * 2269 * This can be called after a batch operation on task events, in which case 2270 * event_type is a bit mask of the types of events involved. For CPU events, 2271 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE. 2272 */ 2273 static void ctx_resched(struct perf_cpu_context *cpuctx, 2274 struct perf_event_context *task_ctx, 2275 enum event_type_t event_type) 2276 { 2277 enum event_type_t ctx_event_type = event_type & EVENT_ALL; 2278 bool cpu_event = !!(event_type & EVENT_CPU); 2279 2280 /* 2281 * If pinned groups are involved, flexible groups also need to be 2282 * scheduled out. 2283 */ 2284 if (event_type & EVENT_PINNED) 2285 event_type |= EVENT_FLEXIBLE; 2286 2287 perf_pmu_disable(cpuctx->ctx.pmu); 2288 if (task_ctx) 2289 task_ctx_sched_out(cpuctx, task_ctx, event_type); 2290 2291 /* 2292 * Decide which cpu ctx groups to schedule out based on the types 2293 * of events that caused rescheduling: 2294 * - EVENT_CPU: schedule out corresponding groups; 2295 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups; 2296 * - otherwise, do nothing more. 2297 */ 2298 if (cpu_event) 2299 cpu_ctx_sched_out(cpuctx, ctx_event_type); 2300 else if (ctx_event_type & EVENT_PINNED) 2301 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); 2302 2303 perf_event_sched_in(cpuctx, task_ctx, current); 2304 perf_pmu_enable(cpuctx->ctx.pmu); 2305 } 2306 2307 /* 2308 * Cross CPU call to install and enable a performance event 2309 * 2310 * Very similar to remote_function() + event_function() but cannot assume that 2311 * things like ctx->is_active and cpuctx->task_ctx are set. 2312 */ 2313 static int __perf_install_in_context(void *info) 2314 { 2315 struct perf_event *event = info; 2316 struct perf_event_context *ctx = event->ctx; 2317 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 2318 struct perf_event_context *task_ctx = cpuctx->task_ctx; 2319 bool reprogram = true; 2320 int ret = 0; 2321 2322 raw_spin_lock(&cpuctx->ctx.lock); 2323 if (ctx->task) { 2324 raw_spin_lock(&ctx->lock); 2325 task_ctx = ctx; 2326 2327 reprogram = (ctx->task == current); 2328 2329 /* 2330 * If the task is running, it must be running on this CPU, 2331 * otherwise we cannot reprogram things. 2332 * 2333 * If its not running, we don't care, ctx->lock will 2334 * serialize against it becoming runnable. 2335 */ 2336 if (task_curr(ctx->task) && !reprogram) { 2337 ret = -ESRCH; 2338 goto unlock; 2339 } 2340 2341 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx); 2342 } else if (task_ctx) { 2343 raw_spin_lock(&task_ctx->lock); 2344 } 2345 2346 if (reprogram) { 2347 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 2348 add_event_to_ctx(event, ctx); 2349 ctx_resched(cpuctx, task_ctx, get_event_type(event)); 2350 } else { 2351 add_event_to_ctx(event, ctx); 2352 } 2353 2354 unlock: 2355 perf_ctx_unlock(cpuctx, task_ctx); 2356 2357 return ret; 2358 } 2359 2360 /* 2361 * Attach a performance event to a context. 2362 * 2363 * Very similar to event_function_call, see comment there. 2364 */ 2365 static void 2366 perf_install_in_context(struct perf_event_context *ctx, 2367 struct perf_event *event, 2368 int cpu) 2369 { 2370 struct task_struct *task = READ_ONCE(ctx->task); 2371 2372 lockdep_assert_held(&ctx->mutex); 2373 2374 if (event->cpu != -1) 2375 event->cpu = cpu; 2376 2377 /* 2378 * Ensures that if we can observe event->ctx, both the event and ctx 2379 * will be 'complete'. See perf_iterate_sb_cpu(). 2380 */ 2381 smp_store_release(&event->ctx, ctx); 2382 2383 if (!task) { 2384 cpu_function_call(cpu, __perf_install_in_context, event); 2385 return; 2386 } 2387 2388 /* 2389 * Should not happen, we validate the ctx is still alive before calling. 2390 */ 2391 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) 2392 return; 2393 2394 /* 2395 * Installing events is tricky because we cannot rely on ctx->is_active 2396 * to be set in case this is the nr_events 0 -> 1 transition. 2397 * 2398 * Instead we use task_curr(), which tells us if the task is running. 2399 * However, since we use task_curr() outside of rq::lock, we can race 2400 * against the actual state. This means the result can be wrong. 2401 * 2402 * If we get a false positive, we retry, this is harmless. 2403 * 2404 * If we get a false negative, things are complicated. If we are after 2405 * perf_event_context_sched_in() ctx::lock will serialize us, and the 2406 * value must be correct. If we're before, it doesn't matter since 2407 * perf_event_context_sched_in() will program the counter. 2408 * 2409 * However, this hinges on the remote context switch having observed 2410 * our task->perf_event_ctxp[] store, such that it will in fact take 2411 * ctx::lock in perf_event_context_sched_in(). 2412 * 2413 * We do this by task_function_call(), if the IPI fails to hit the task 2414 * we know any future context switch of task must see the 2415 * perf_event_ctpx[] store. 2416 */ 2417 2418 /* 2419 * This smp_mb() orders the task->perf_event_ctxp[] store with the 2420 * task_cpu() load, such that if the IPI then does not find the task 2421 * running, a future context switch of that task must observe the 2422 * store. 2423 */ 2424 smp_mb(); 2425 again: 2426 if (!task_function_call(task, __perf_install_in_context, event)) 2427 return; 2428 2429 raw_spin_lock_irq(&ctx->lock); 2430 task = ctx->task; 2431 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) { 2432 /* 2433 * Cannot happen because we already checked above (which also 2434 * cannot happen), and we hold ctx->mutex, which serializes us 2435 * against perf_event_exit_task_context(). 2436 */ 2437 raw_spin_unlock_irq(&ctx->lock); 2438 return; 2439 } 2440 /* 2441 * If the task is not running, ctx->lock will avoid it becoming so, 2442 * thus we can safely install the event. 2443 */ 2444 if (task_curr(task)) { 2445 raw_spin_unlock_irq(&ctx->lock); 2446 goto again; 2447 } 2448 add_event_to_ctx(event, ctx); 2449 raw_spin_unlock_irq(&ctx->lock); 2450 } 2451 2452 /* 2453 * Put a event into inactive state and update time fields. 2454 * Enabling the leader of a group effectively enables all 2455 * the group members that aren't explicitly disabled, so we 2456 * have to update their ->tstamp_enabled also. 2457 * Note: this works for group members as well as group leaders 2458 * since the non-leader members' sibling_lists will be empty. 2459 */ 2460 static void __perf_event_mark_enabled(struct perf_event *event) 2461 { 2462 struct perf_event *sub; 2463 u64 tstamp = perf_event_time(event); 2464 2465 event->state = PERF_EVENT_STATE_INACTIVE; 2466 event->tstamp_enabled = tstamp - event->total_time_enabled; 2467 list_for_each_entry(sub, &event->sibling_list, group_entry) { 2468 if (sub->state >= PERF_EVENT_STATE_INACTIVE) 2469 sub->tstamp_enabled = tstamp - sub->total_time_enabled; 2470 } 2471 } 2472 2473 /* 2474 * Cross CPU call to enable a performance event 2475 */ 2476 static void __perf_event_enable(struct perf_event *event, 2477 struct perf_cpu_context *cpuctx, 2478 struct perf_event_context *ctx, 2479 void *info) 2480 { 2481 struct perf_event *leader = event->group_leader; 2482 struct perf_event_context *task_ctx; 2483 2484 if (event->state >= PERF_EVENT_STATE_INACTIVE || 2485 event->state <= PERF_EVENT_STATE_ERROR) 2486 return; 2487 2488 if (ctx->is_active) 2489 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 2490 2491 __perf_event_mark_enabled(event); 2492 2493 if (!ctx->is_active) 2494 return; 2495 2496 if (!event_filter_match(event)) { 2497 if (is_cgroup_event(event)) 2498 perf_cgroup_defer_enabled(event); 2499 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current); 2500 return; 2501 } 2502 2503 /* 2504 * If the event is in a group and isn't the group leader, 2505 * then don't put it on unless the group is on. 2506 */ 2507 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) { 2508 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current); 2509 return; 2510 } 2511 2512 task_ctx = cpuctx->task_ctx; 2513 if (ctx->task) 2514 WARN_ON_ONCE(task_ctx != ctx); 2515 2516 ctx_resched(cpuctx, task_ctx, get_event_type(event)); 2517 } 2518 2519 /* 2520 * Enable a event. 2521 * 2522 * If event->ctx is a cloned context, callers must make sure that 2523 * every task struct that event->ctx->task could possibly point to 2524 * remains valid. This condition is satisfied when called through 2525 * perf_event_for_each_child or perf_event_for_each as described 2526 * for perf_event_disable. 2527 */ 2528 static void _perf_event_enable(struct perf_event *event) 2529 { 2530 struct perf_event_context *ctx = event->ctx; 2531 2532 raw_spin_lock_irq(&ctx->lock); 2533 if (event->state >= PERF_EVENT_STATE_INACTIVE || 2534 event->state < PERF_EVENT_STATE_ERROR) { 2535 raw_spin_unlock_irq(&ctx->lock); 2536 return; 2537 } 2538 2539 /* 2540 * If the event is in error state, clear that first. 2541 * 2542 * That way, if we see the event in error state below, we know that it 2543 * has gone back into error state, as distinct from the task having 2544 * been scheduled away before the cross-call arrived. 2545 */ 2546 if (event->state == PERF_EVENT_STATE_ERROR) 2547 event->state = PERF_EVENT_STATE_OFF; 2548 raw_spin_unlock_irq(&ctx->lock); 2549 2550 event_function_call(event, __perf_event_enable, NULL); 2551 } 2552 2553 /* 2554 * See perf_event_disable(); 2555 */ 2556 void perf_event_enable(struct perf_event *event) 2557 { 2558 struct perf_event_context *ctx; 2559 2560 ctx = perf_event_ctx_lock(event); 2561 _perf_event_enable(event); 2562 perf_event_ctx_unlock(event, ctx); 2563 } 2564 EXPORT_SYMBOL_GPL(perf_event_enable); 2565 2566 struct stop_event_data { 2567 struct perf_event *event; 2568 unsigned int restart; 2569 }; 2570 2571 static int __perf_event_stop(void *info) 2572 { 2573 struct stop_event_data *sd = info; 2574 struct perf_event *event = sd->event; 2575 2576 /* if it's already INACTIVE, do nothing */ 2577 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) 2578 return 0; 2579 2580 /* matches smp_wmb() in event_sched_in() */ 2581 smp_rmb(); 2582 2583 /* 2584 * There is a window with interrupts enabled before we get here, 2585 * so we need to check again lest we try to stop another CPU's event. 2586 */ 2587 if (READ_ONCE(event->oncpu) != smp_processor_id()) 2588 return -EAGAIN; 2589 2590 event->pmu->stop(event, PERF_EF_UPDATE); 2591 2592 /* 2593 * May race with the actual stop (through perf_pmu_output_stop()), 2594 * but it is only used for events with AUX ring buffer, and such 2595 * events will refuse to restart because of rb::aux_mmap_count==0, 2596 * see comments in perf_aux_output_begin(). 2597 * 2598 * Since this is happening on a event-local CPU, no trace is lost 2599 * while restarting. 2600 */ 2601 if (sd->restart) 2602 event->pmu->start(event, 0); 2603 2604 return 0; 2605 } 2606 2607 static int perf_event_stop(struct perf_event *event, int restart) 2608 { 2609 struct stop_event_data sd = { 2610 .event = event, 2611 .restart = restart, 2612 }; 2613 int ret = 0; 2614 2615 do { 2616 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) 2617 return 0; 2618 2619 /* matches smp_wmb() in event_sched_in() */ 2620 smp_rmb(); 2621 2622 /* 2623 * We only want to restart ACTIVE events, so if the event goes 2624 * inactive here (event->oncpu==-1), there's nothing more to do; 2625 * fall through with ret==-ENXIO. 2626 */ 2627 ret = cpu_function_call(READ_ONCE(event->oncpu), 2628 __perf_event_stop, &sd); 2629 } while (ret == -EAGAIN); 2630 2631 return ret; 2632 } 2633 2634 /* 2635 * In order to contain the amount of racy and tricky in the address filter 2636 * configuration management, it is a two part process: 2637 * 2638 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below, 2639 * we update the addresses of corresponding vmas in 2640 * event::addr_filters_offs array and bump the event::addr_filters_gen; 2641 * (p2) when an event is scheduled in (pmu::add), it calls 2642 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync() 2643 * if the generation has changed since the previous call. 2644 * 2645 * If (p1) happens while the event is active, we restart it to force (p2). 2646 * 2647 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on 2648 * pre-existing mappings, called once when new filters arrive via SET_FILTER 2649 * ioctl; 2650 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly 2651 * registered mapping, called for every new mmap(), with mm::mmap_sem down 2652 * for reading; 2653 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process 2654 * of exec. 2655 */ 2656 void perf_event_addr_filters_sync(struct perf_event *event) 2657 { 2658 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 2659 2660 if (!has_addr_filter(event)) 2661 return; 2662 2663 raw_spin_lock(&ifh->lock); 2664 if (event->addr_filters_gen != event->hw.addr_filters_gen) { 2665 event->pmu->addr_filters_sync(event); 2666 event->hw.addr_filters_gen = event->addr_filters_gen; 2667 } 2668 raw_spin_unlock(&ifh->lock); 2669 } 2670 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync); 2671 2672 static int _perf_event_refresh(struct perf_event *event, int refresh) 2673 { 2674 /* 2675 * not supported on inherited events 2676 */ 2677 if (event->attr.inherit || !is_sampling_event(event)) 2678 return -EINVAL; 2679 2680 atomic_add(refresh, &event->event_limit); 2681 _perf_event_enable(event); 2682 2683 return 0; 2684 } 2685 2686 /* 2687 * See perf_event_disable() 2688 */ 2689 int perf_event_refresh(struct perf_event *event, int refresh) 2690 { 2691 struct perf_event_context *ctx; 2692 int ret; 2693 2694 ctx = perf_event_ctx_lock(event); 2695 ret = _perf_event_refresh(event, refresh); 2696 perf_event_ctx_unlock(event, ctx); 2697 2698 return ret; 2699 } 2700 EXPORT_SYMBOL_GPL(perf_event_refresh); 2701 2702 static void ctx_sched_out(struct perf_event_context *ctx, 2703 struct perf_cpu_context *cpuctx, 2704 enum event_type_t event_type) 2705 { 2706 int is_active = ctx->is_active; 2707 struct perf_event *event; 2708 2709 lockdep_assert_held(&ctx->lock); 2710 2711 if (likely(!ctx->nr_events)) { 2712 /* 2713 * See __perf_remove_from_context(). 2714 */ 2715 WARN_ON_ONCE(ctx->is_active); 2716 if (ctx->task) 2717 WARN_ON_ONCE(cpuctx->task_ctx); 2718 return; 2719 } 2720 2721 ctx->is_active &= ~event_type; 2722 if (!(ctx->is_active & EVENT_ALL)) 2723 ctx->is_active = 0; 2724 2725 if (ctx->task) { 2726 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 2727 if (!ctx->is_active) 2728 cpuctx->task_ctx = NULL; 2729 } 2730 2731 /* 2732 * Always update time if it was set; not only when it changes. 2733 * Otherwise we can 'forget' to update time for any but the last 2734 * context we sched out. For example: 2735 * 2736 * ctx_sched_out(.event_type = EVENT_FLEXIBLE) 2737 * ctx_sched_out(.event_type = EVENT_PINNED) 2738 * 2739 * would only update time for the pinned events. 2740 */ 2741 if (is_active & EVENT_TIME) { 2742 /* update (and stop) ctx time */ 2743 update_context_time(ctx); 2744 update_cgrp_time_from_cpuctx(cpuctx); 2745 } 2746 2747 is_active ^= ctx->is_active; /* changed bits */ 2748 2749 if (!ctx->nr_active || !(is_active & EVENT_ALL)) 2750 return; 2751 2752 perf_pmu_disable(ctx->pmu); 2753 if (is_active & EVENT_PINNED) { 2754 list_for_each_entry(event, &ctx->pinned_groups, group_entry) 2755 group_sched_out(event, cpuctx, ctx); 2756 } 2757 2758 if (is_active & EVENT_FLEXIBLE) { 2759 list_for_each_entry(event, &ctx->flexible_groups, group_entry) 2760 group_sched_out(event, cpuctx, ctx); 2761 } 2762 perf_pmu_enable(ctx->pmu); 2763 } 2764 2765 /* 2766 * Test whether two contexts are equivalent, i.e. whether they have both been 2767 * cloned from the same version of the same context. 2768 * 2769 * Equivalence is measured using a generation number in the context that is 2770 * incremented on each modification to it; see unclone_ctx(), list_add_event() 2771 * and list_del_event(). 2772 */ 2773 static int context_equiv(struct perf_event_context *ctx1, 2774 struct perf_event_context *ctx2) 2775 { 2776 lockdep_assert_held(&ctx1->lock); 2777 lockdep_assert_held(&ctx2->lock); 2778 2779 /* Pinning disables the swap optimization */ 2780 if (ctx1->pin_count || ctx2->pin_count) 2781 return 0; 2782 2783 /* If ctx1 is the parent of ctx2 */ 2784 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen) 2785 return 1; 2786 2787 /* If ctx2 is the parent of ctx1 */ 2788 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation) 2789 return 1; 2790 2791 /* 2792 * If ctx1 and ctx2 have the same parent; we flatten the parent 2793 * hierarchy, see perf_event_init_context(). 2794 */ 2795 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx && 2796 ctx1->parent_gen == ctx2->parent_gen) 2797 return 1; 2798 2799 /* Unmatched */ 2800 return 0; 2801 } 2802 2803 static void __perf_event_sync_stat(struct perf_event *event, 2804 struct perf_event *next_event) 2805 { 2806 u64 value; 2807 2808 if (!event->attr.inherit_stat) 2809 return; 2810 2811 /* 2812 * Update the event value, we cannot use perf_event_read() 2813 * because we're in the middle of a context switch and have IRQs 2814 * disabled, which upsets smp_call_function_single(), however 2815 * we know the event must be on the current CPU, therefore we 2816 * don't need to use it. 2817 */ 2818 switch (event->state) { 2819 case PERF_EVENT_STATE_ACTIVE: 2820 event->pmu->read(event); 2821 /* fall-through */ 2822 2823 case PERF_EVENT_STATE_INACTIVE: 2824 update_event_times(event); 2825 break; 2826 2827 default: 2828 break; 2829 } 2830 2831 /* 2832 * In order to keep per-task stats reliable we need to flip the event 2833 * values when we flip the contexts. 2834 */ 2835 value = local64_read(&next_event->count); 2836 value = local64_xchg(&event->count, value); 2837 local64_set(&next_event->count, value); 2838 2839 swap(event->total_time_enabled, next_event->total_time_enabled); 2840 swap(event->total_time_running, next_event->total_time_running); 2841 2842 /* 2843 * Since we swizzled the values, update the user visible data too. 2844 */ 2845 perf_event_update_userpage(event); 2846 perf_event_update_userpage(next_event); 2847 } 2848 2849 static void perf_event_sync_stat(struct perf_event_context *ctx, 2850 struct perf_event_context *next_ctx) 2851 { 2852 struct perf_event *event, *next_event; 2853 2854 if (!ctx->nr_stat) 2855 return; 2856 2857 update_context_time(ctx); 2858 2859 event = list_first_entry(&ctx->event_list, 2860 struct perf_event, event_entry); 2861 2862 next_event = list_first_entry(&next_ctx->event_list, 2863 struct perf_event, event_entry); 2864 2865 while (&event->event_entry != &ctx->event_list && 2866 &next_event->event_entry != &next_ctx->event_list) { 2867 2868 __perf_event_sync_stat(event, next_event); 2869 2870 event = list_next_entry(event, event_entry); 2871 next_event = list_next_entry(next_event, event_entry); 2872 } 2873 } 2874 2875 static void perf_event_context_sched_out(struct task_struct *task, int ctxn, 2876 struct task_struct *next) 2877 { 2878 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn]; 2879 struct perf_event_context *next_ctx; 2880 struct perf_event_context *parent, *next_parent; 2881 struct perf_cpu_context *cpuctx; 2882 int do_switch = 1; 2883 2884 if (likely(!ctx)) 2885 return; 2886 2887 cpuctx = __get_cpu_context(ctx); 2888 if (!cpuctx->task_ctx) 2889 return; 2890 2891 rcu_read_lock(); 2892 next_ctx = next->perf_event_ctxp[ctxn]; 2893 if (!next_ctx) 2894 goto unlock; 2895 2896 parent = rcu_dereference(ctx->parent_ctx); 2897 next_parent = rcu_dereference(next_ctx->parent_ctx); 2898 2899 /* If neither context have a parent context; they cannot be clones. */ 2900 if (!parent && !next_parent) 2901 goto unlock; 2902 2903 if (next_parent == ctx || next_ctx == parent || next_parent == parent) { 2904 /* 2905 * Looks like the two contexts are clones, so we might be 2906 * able to optimize the context switch. We lock both 2907 * contexts and check that they are clones under the 2908 * lock (including re-checking that neither has been 2909 * uncloned in the meantime). It doesn't matter which 2910 * order we take the locks because no other cpu could 2911 * be trying to lock both of these tasks. 2912 */ 2913 raw_spin_lock(&ctx->lock); 2914 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING); 2915 if (context_equiv(ctx, next_ctx)) { 2916 WRITE_ONCE(ctx->task, next); 2917 WRITE_ONCE(next_ctx->task, task); 2918 2919 swap(ctx->task_ctx_data, next_ctx->task_ctx_data); 2920 2921 /* 2922 * RCU_INIT_POINTER here is safe because we've not 2923 * modified the ctx and the above modification of 2924 * ctx->task and ctx->task_ctx_data are immaterial 2925 * since those values are always verified under 2926 * ctx->lock which we're now holding. 2927 */ 2928 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx); 2929 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx); 2930 2931 do_switch = 0; 2932 2933 perf_event_sync_stat(ctx, next_ctx); 2934 } 2935 raw_spin_unlock(&next_ctx->lock); 2936 raw_spin_unlock(&ctx->lock); 2937 } 2938 unlock: 2939 rcu_read_unlock(); 2940 2941 if (do_switch) { 2942 raw_spin_lock(&ctx->lock); 2943 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL); 2944 raw_spin_unlock(&ctx->lock); 2945 } 2946 } 2947 2948 static DEFINE_PER_CPU(struct list_head, sched_cb_list); 2949 2950 void perf_sched_cb_dec(struct pmu *pmu) 2951 { 2952 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 2953 2954 this_cpu_dec(perf_sched_cb_usages); 2955 2956 if (!--cpuctx->sched_cb_usage) 2957 list_del(&cpuctx->sched_cb_entry); 2958 } 2959 2960 2961 void perf_sched_cb_inc(struct pmu *pmu) 2962 { 2963 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 2964 2965 if (!cpuctx->sched_cb_usage++) 2966 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list)); 2967 2968 this_cpu_inc(perf_sched_cb_usages); 2969 } 2970 2971 /* 2972 * This function provides the context switch callback to the lower code 2973 * layer. It is invoked ONLY when the context switch callback is enabled. 2974 * 2975 * This callback is relevant even to per-cpu events; for example multi event 2976 * PEBS requires this to provide PID/TID information. This requires we flush 2977 * all queued PEBS records before we context switch to a new task. 2978 */ 2979 static void perf_pmu_sched_task(struct task_struct *prev, 2980 struct task_struct *next, 2981 bool sched_in) 2982 { 2983 struct perf_cpu_context *cpuctx; 2984 struct pmu *pmu; 2985 2986 if (prev == next) 2987 return; 2988 2989 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) { 2990 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */ 2991 2992 if (WARN_ON_ONCE(!pmu->sched_task)) 2993 continue; 2994 2995 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 2996 perf_pmu_disable(pmu); 2997 2998 pmu->sched_task(cpuctx->task_ctx, sched_in); 2999 3000 perf_pmu_enable(pmu); 3001 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 3002 } 3003 } 3004 3005 static void perf_event_switch(struct task_struct *task, 3006 struct task_struct *next_prev, bool sched_in); 3007 3008 #define for_each_task_context_nr(ctxn) \ 3009 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++) 3010 3011 /* 3012 * Called from scheduler to remove the events of the current task, 3013 * with interrupts disabled. 3014 * 3015 * We stop each event and update the event value in event->count. 3016 * 3017 * This does not protect us against NMI, but disable() 3018 * sets the disabled bit in the control field of event _before_ 3019 * accessing the event control register. If a NMI hits, then it will 3020 * not restart the event. 3021 */ 3022 void __perf_event_task_sched_out(struct task_struct *task, 3023 struct task_struct *next) 3024 { 3025 int ctxn; 3026 3027 if (__this_cpu_read(perf_sched_cb_usages)) 3028 perf_pmu_sched_task(task, next, false); 3029 3030 if (atomic_read(&nr_switch_events)) 3031 perf_event_switch(task, next, false); 3032 3033 for_each_task_context_nr(ctxn) 3034 perf_event_context_sched_out(task, ctxn, next); 3035 3036 /* 3037 * if cgroup events exist on this CPU, then we need 3038 * to check if we have to switch out PMU state. 3039 * cgroup event are system-wide mode only 3040 */ 3041 if (atomic_read(this_cpu_ptr(&perf_cgroup_events))) 3042 perf_cgroup_sched_out(task, next); 3043 } 3044 3045 /* 3046 * Called with IRQs disabled 3047 */ 3048 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, 3049 enum event_type_t event_type) 3050 { 3051 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type); 3052 } 3053 3054 static void 3055 ctx_pinned_sched_in(struct perf_event_context *ctx, 3056 struct perf_cpu_context *cpuctx) 3057 { 3058 struct perf_event *event; 3059 3060 list_for_each_entry(event, &ctx->pinned_groups, group_entry) { 3061 if (event->state <= PERF_EVENT_STATE_OFF) 3062 continue; 3063 if (!event_filter_match(event)) 3064 continue; 3065 3066 /* may need to reset tstamp_enabled */ 3067 if (is_cgroup_event(event)) 3068 perf_cgroup_mark_enabled(event, ctx); 3069 3070 if (group_can_go_on(event, cpuctx, 1)) 3071 group_sched_in(event, cpuctx, ctx); 3072 3073 /* 3074 * If this pinned group hasn't been scheduled, 3075 * put it in error state. 3076 */ 3077 if (event->state == PERF_EVENT_STATE_INACTIVE) { 3078 update_group_times(event); 3079 event->state = PERF_EVENT_STATE_ERROR; 3080 } 3081 } 3082 } 3083 3084 static void 3085 ctx_flexible_sched_in(struct perf_event_context *ctx, 3086 struct perf_cpu_context *cpuctx) 3087 { 3088 struct perf_event *event; 3089 int can_add_hw = 1; 3090 3091 list_for_each_entry(event, &ctx->flexible_groups, group_entry) { 3092 /* Ignore events in OFF or ERROR state */ 3093 if (event->state <= PERF_EVENT_STATE_OFF) 3094 continue; 3095 /* 3096 * Listen to the 'cpu' scheduling filter constraint 3097 * of events: 3098 */ 3099 if (!event_filter_match(event)) 3100 continue; 3101 3102 /* may need to reset tstamp_enabled */ 3103 if (is_cgroup_event(event)) 3104 perf_cgroup_mark_enabled(event, ctx); 3105 3106 if (group_can_go_on(event, cpuctx, can_add_hw)) { 3107 if (group_sched_in(event, cpuctx, ctx)) 3108 can_add_hw = 0; 3109 } 3110 } 3111 } 3112 3113 static void 3114 ctx_sched_in(struct perf_event_context *ctx, 3115 struct perf_cpu_context *cpuctx, 3116 enum event_type_t event_type, 3117 struct task_struct *task) 3118 { 3119 int is_active = ctx->is_active; 3120 u64 now; 3121 3122 lockdep_assert_held(&ctx->lock); 3123 3124 if (likely(!ctx->nr_events)) 3125 return; 3126 3127 ctx->is_active |= (event_type | EVENT_TIME); 3128 if (ctx->task) { 3129 if (!is_active) 3130 cpuctx->task_ctx = ctx; 3131 else 3132 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 3133 } 3134 3135 is_active ^= ctx->is_active; /* changed bits */ 3136 3137 if (is_active & EVENT_TIME) { 3138 /* start ctx time */ 3139 now = perf_clock(); 3140 ctx->timestamp = now; 3141 perf_cgroup_set_timestamp(task, ctx); 3142 } 3143 3144 /* 3145 * First go through the list and put on any pinned groups 3146 * in order to give them the best chance of going on. 3147 */ 3148 if (is_active & EVENT_PINNED) 3149 ctx_pinned_sched_in(ctx, cpuctx); 3150 3151 /* Then walk through the lower prio flexible groups */ 3152 if (is_active & EVENT_FLEXIBLE) 3153 ctx_flexible_sched_in(ctx, cpuctx); 3154 } 3155 3156 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, 3157 enum event_type_t event_type, 3158 struct task_struct *task) 3159 { 3160 struct perf_event_context *ctx = &cpuctx->ctx; 3161 3162 ctx_sched_in(ctx, cpuctx, event_type, task); 3163 } 3164 3165 static void perf_event_context_sched_in(struct perf_event_context *ctx, 3166 struct task_struct *task) 3167 { 3168 struct perf_cpu_context *cpuctx; 3169 3170 cpuctx = __get_cpu_context(ctx); 3171 if (cpuctx->task_ctx == ctx) 3172 return; 3173 3174 perf_ctx_lock(cpuctx, ctx); 3175 perf_pmu_disable(ctx->pmu); 3176 /* 3177 * We want to keep the following priority order: 3178 * cpu pinned (that don't need to move), task pinned, 3179 * cpu flexible, task flexible. 3180 * 3181 * However, if task's ctx is not carrying any pinned 3182 * events, no need to flip the cpuctx's events around. 3183 */ 3184 if (!list_empty(&ctx->pinned_groups)) 3185 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); 3186 perf_event_sched_in(cpuctx, ctx, task); 3187 perf_pmu_enable(ctx->pmu); 3188 perf_ctx_unlock(cpuctx, ctx); 3189 } 3190 3191 /* 3192 * Called from scheduler to add the events of the current task 3193 * with interrupts disabled. 3194 * 3195 * We restore the event value and then enable it. 3196 * 3197 * This does not protect us against NMI, but enable() 3198 * sets the enabled bit in the control field of event _before_ 3199 * accessing the event control register. If a NMI hits, then it will 3200 * keep the event running. 3201 */ 3202 void __perf_event_task_sched_in(struct task_struct *prev, 3203 struct task_struct *task) 3204 { 3205 struct perf_event_context *ctx; 3206 int ctxn; 3207 3208 /* 3209 * If cgroup events exist on this CPU, then we need to check if we have 3210 * to switch in PMU state; cgroup event are system-wide mode only. 3211 * 3212 * Since cgroup events are CPU events, we must schedule these in before 3213 * we schedule in the task events. 3214 */ 3215 if (atomic_read(this_cpu_ptr(&perf_cgroup_events))) 3216 perf_cgroup_sched_in(prev, task); 3217 3218 for_each_task_context_nr(ctxn) { 3219 ctx = task->perf_event_ctxp[ctxn]; 3220 if (likely(!ctx)) 3221 continue; 3222 3223 perf_event_context_sched_in(ctx, task); 3224 } 3225 3226 if (atomic_read(&nr_switch_events)) 3227 perf_event_switch(task, prev, true); 3228 3229 if (__this_cpu_read(perf_sched_cb_usages)) 3230 perf_pmu_sched_task(prev, task, true); 3231 } 3232 3233 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count) 3234 { 3235 u64 frequency = event->attr.sample_freq; 3236 u64 sec = NSEC_PER_SEC; 3237 u64 divisor, dividend; 3238 3239 int count_fls, nsec_fls, frequency_fls, sec_fls; 3240 3241 count_fls = fls64(count); 3242 nsec_fls = fls64(nsec); 3243 frequency_fls = fls64(frequency); 3244 sec_fls = 30; 3245 3246 /* 3247 * We got @count in @nsec, with a target of sample_freq HZ 3248 * the target period becomes: 3249 * 3250 * @count * 10^9 3251 * period = ------------------- 3252 * @nsec * sample_freq 3253 * 3254 */ 3255 3256 /* 3257 * Reduce accuracy by one bit such that @a and @b converge 3258 * to a similar magnitude. 3259 */ 3260 #define REDUCE_FLS(a, b) \ 3261 do { \ 3262 if (a##_fls > b##_fls) { \ 3263 a >>= 1; \ 3264 a##_fls--; \ 3265 } else { \ 3266 b >>= 1; \ 3267 b##_fls--; \ 3268 } \ 3269 } while (0) 3270 3271 /* 3272 * Reduce accuracy until either term fits in a u64, then proceed with 3273 * the other, so that finally we can do a u64/u64 division. 3274 */ 3275 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) { 3276 REDUCE_FLS(nsec, frequency); 3277 REDUCE_FLS(sec, count); 3278 } 3279 3280 if (count_fls + sec_fls > 64) { 3281 divisor = nsec * frequency; 3282 3283 while (count_fls + sec_fls > 64) { 3284 REDUCE_FLS(count, sec); 3285 divisor >>= 1; 3286 } 3287 3288 dividend = count * sec; 3289 } else { 3290 dividend = count * sec; 3291 3292 while (nsec_fls + frequency_fls > 64) { 3293 REDUCE_FLS(nsec, frequency); 3294 dividend >>= 1; 3295 } 3296 3297 divisor = nsec * frequency; 3298 } 3299 3300 if (!divisor) 3301 return dividend; 3302 3303 return div64_u64(dividend, divisor); 3304 } 3305 3306 static DEFINE_PER_CPU(int, perf_throttled_count); 3307 static DEFINE_PER_CPU(u64, perf_throttled_seq); 3308 3309 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable) 3310 { 3311 struct hw_perf_event *hwc = &event->hw; 3312 s64 period, sample_period; 3313 s64 delta; 3314 3315 period = perf_calculate_period(event, nsec, count); 3316 3317 delta = (s64)(period - hwc->sample_period); 3318 delta = (delta + 7) / 8; /* low pass filter */ 3319 3320 sample_period = hwc->sample_period + delta; 3321 3322 if (!sample_period) 3323 sample_period = 1; 3324 3325 hwc->sample_period = sample_period; 3326 3327 if (local64_read(&hwc->period_left) > 8*sample_period) { 3328 if (disable) 3329 event->pmu->stop(event, PERF_EF_UPDATE); 3330 3331 local64_set(&hwc->period_left, 0); 3332 3333 if (disable) 3334 event->pmu->start(event, PERF_EF_RELOAD); 3335 } 3336 } 3337 3338 /* 3339 * combine freq adjustment with unthrottling to avoid two passes over the 3340 * events. At the same time, make sure, having freq events does not change 3341 * the rate of unthrottling as that would introduce bias. 3342 */ 3343 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx, 3344 int needs_unthr) 3345 { 3346 struct perf_event *event; 3347 struct hw_perf_event *hwc; 3348 u64 now, period = TICK_NSEC; 3349 s64 delta; 3350 3351 /* 3352 * only need to iterate over all events iff: 3353 * - context have events in frequency mode (needs freq adjust) 3354 * - there are events to unthrottle on this cpu 3355 */ 3356 if (!(ctx->nr_freq || needs_unthr)) 3357 return; 3358 3359 raw_spin_lock(&ctx->lock); 3360 perf_pmu_disable(ctx->pmu); 3361 3362 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 3363 if (event->state != PERF_EVENT_STATE_ACTIVE) 3364 continue; 3365 3366 if (!event_filter_match(event)) 3367 continue; 3368 3369 perf_pmu_disable(event->pmu); 3370 3371 hwc = &event->hw; 3372 3373 if (hwc->interrupts == MAX_INTERRUPTS) { 3374 hwc->interrupts = 0; 3375 perf_log_throttle(event, 1); 3376 event->pmu->start(event, 0); 3377 } 3378 3379 if (!event->attr.freq || !event->attr.sample_freq) 3380 goto next; 3381 3382 /* 3383 * stop the event and update event->count 3384 */ 3385 event->pmu->stop(event, PERF_EF_UPDATE); 3386 3387 now = local64_read(&event->count); 3388 delta = now - hwc->freq_count_stamp; 3389 hwc->freq_count_stamp = now; 3390 3391 /* 3392 * restart the event 3393 * reload only if value has changed 3394 * we have stopped the event so tell that 3395 * to perf_adjust_period() to avoid stopping it 3396 * twice. 3397 */ 3398 if (delta > 0) 3399 perf_adjust_period(event, period, delta, false); 3400 3401 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0); 3402 next: 3403 perf_pmu_enable(event->pmu); 3404 } 3405 3406 perf_pmu_enable(ctx->pmu); 3407 raw_spin_unlock(&ctx->lock); 3408 } 3409 3410 /* 3411 * Round-robin a context's events: 3412 */ 3413 static void rotate_ctx(struct perf_event_context *ctx) 3414 { 3415 /* 3416 * Rotate the first entry last of non-pinned groups. Rotation might be 3417 * disabled by the inheritance code. 3418 */ 3419 if (!ctx->rotate_disable) 3420 list_rotate_left(&ctx->flexible_groups); 3421 } 3422 3423 static int perf_rotate_context(struct perf_cpu_context *cpuctx) 3424 { 3425 struct perf_event_context *ctx = NULL; 3426 int rotate = 0; 3427 3428 if (cpuctx->ctx.nr_events) { 3429 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active) 3430 rotate = 1; 3431 } 3432 3433 ctx = cpuctx->task_ctx; 3434 if (ctx && ctx->nr_events) { 3435 if (ctx->nr_events != ctx->nr_active) 3436 rotate = 1; 3437 } 3438 3439 if (!rotate) 3440 goto done; 3441 3442 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 3443 perf_pmu_disable(cpuctx->ctx.pmu); 3444 3445 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); 3446 if (ctx) 3447 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE); 3448 3449 rotate_ctx(&cpuctx->ctx); 3450 if (ctx) 3451 rotate_ctx(ctx); 3452 3453 perf_event_sched_in(cpuctx, ctx, current); 3454 3455 perf_pmu_enable(cpuctx->ctx.pmu); 3456 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 3457 done: 3458 3459 return rotate; 3460 } 3461 3462 void perf_event_task_tick(void) 3463 { 3464 struct list_head *head = this_cpu_ptr(&active_ctx_list); 3465 struct perf_event_context *ctx, *tmp; 3466 int throttled; 3467 3468 WARN_ON(!irqs_disabled()); 3469 3470 __this_cpu_inc(perf_throttled_seq); 3471 throttled = __this_cpu_xchg(perf_throttled_count, 0); 3472 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); 3473 3474 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list) 3475 perf_adjust_freq_unthr_context(ctx, throttled); 3476 } 3477 3478 static int event_enable_on_exec(struct perf_event *event, 3479 struct perf_event_context *ctx) 3480 { 3481 if (!event->attr.enable_on_exec) 3482 return 0; 3483 3484 event->attr.enable_on_exec = 0; 3485 if (event->state >= PERF_EVENT_STATE_INACTIVE) 3486 return 0; 3487 3488 __perf_event_mark_enabled(event); 3489 3490 return 1; 3491 } 3492 3493 /* 3494 * Enable all of a task's events that have been marked enable-on-exec. 3495 * This expects task == current. 3496 */ 3497 static void perf_event_enable_on_exec(int ctxn) 3498 { 3499 struct perf_event_context *ctx, *clone_ctx = NULL; 3500 enum event_type_t event_type = 0; 3501 struct perf_cpu_context *cpuctx; 3502 struct perf_event *event; 3503 unsigned long flags; 3504 int enabled = 0; 3505 3506 local_irq_save(flags); 3507 ctx = current->perf_event_ctxp[ctxn]; 3508 if (!ctx || !ctx->nr_events) 3509 goto out; 3510 3511 cpuctx = __get_cpu_context(ctx); 3512 perf_ctx_lock(cpuctx, ctx); 3513 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 3514 list_for_each_entry(event, &ctx->event_list, event_entry) { 3515 enabled |= event_enable_on_exec(event, ctx); 3516 event_type |= get_event_type(event); 3517 } 3518 3519 /* 3520 * Unclone and reschedule this context if we enabled any event. 3521 */ 3522 if (enabled) { 3523 clone_ctx = unclone_ctx(ctx); 3524 ctx_resched(cpuctx, ctx, event_type); 3525 } 3526 perf_ctx_unlock(cpuctx, ctx); 3527 3528 out: 3529 local_irq_restore(flags); 3530 3531 if (clone_ctx) 3532 put_ctx(clone_ctx); 3533 } 3534 3535 struct perf_read_data { 3536 struct perf_event *event; 3537 bool group; 3538 int ret; 3539 }; 3540 3541 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu) 3542 { 3543 u16 local_pkg, event_pkg; 3544 3545 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) { 3546 int local_cpu = smp_processor_id(); 3547 3548 event_pkg = topology_physical_package_id(event_cpu); 3549 local_pkg = topology_physical_package_id(local_cpu); 3550 3551 if (event_pkg == local_pkg) 3552 return local_cpu; 3553 } 3554 3555 return event_cpu; 3556 } 3557 3558 /* 3559 * Cross CPU call to read the hardware event 3560 */ 3561 static void __perf_event_read(void *info) 3562 { 3563 struct perf_read_data *data = info; 3564 struct perf_event *sub, *event = data->event; 3565 struct perf_event_context *ctx = event->ctx; 3566 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 3567 struct pmu *pmu = event->pmu; 3568 3569 /* 3570 * If this is a task context, we need to check whether it is 3571 * the current task context of this cpu. If not it has been 3572 * scheduled out before the smp call arrived. In that case 3573 * event->count would have been updated to a recent sample 3574 * when the event was scheduled out. 3575 */ 3576 if (ctx->task && cpuctx->task_ctx != ctx) 3577 return; 3578 3579 raw_spin_lock(&ctx->lock); 3580 if (ctx->is_active) { 3581 update_context_time(ctx); 3582 update_cgrp_time_from_event(event); 3583 } 3584 3585 update_event_times(event); 3586 if (event->state != PERF_EVENT_STATE_ACTIVE) 3587 goto unlock; 3588 3589 if (!data->group) { 3590 pmu->read(event); 3591 data->ret = 0; 3592 goto unlock; 3593 } 3594 3595 pmu->start_txn(pmu, PERF_PMU_TXN_READ); 3596 3597 pmu->read(event); 3598 3599 list_for_each_entry(sub, &event->sibling_list, group_entry) { 3600 update_event_times(sub); 3601 if (sub->state == PERF_EVENT_STATE_ACTIVE) { 3602 /* 3603 * Use sibling's PMU rather than @event's since 3604 * sibling could be on different (eg: software) PMU. 3605 */ 3606 sub->pmu->read(sub); 3607 } 3608 } 3609 3610 data->ret = pmu->commit_txn(pmu); 3611 3612 unlock: 3613 raw_spin_unlock(&ctx->lock); 3614 } 3615 3616 static inline u64 perf_event_count(struct perf_event *event) 3617 { 3618 if (event->pmu->count) 3619 return event->pmu->count(event); 3620 3621 return __perf_event_count(event); 3622 } 3623 3624 /* 3625 * NMI-safe method to read a local event, that is an event that 3626 * is: 3627 * - either for the current task, or for this CPU 3628 * - does not have inherit set, for inherited task events 3629 * will not be local and we cannot read them atomically 3630 * - must not have a pmu::count method 3631 */ 3632 u64 perf_event_read_local(struct perf_event *event) 3633 { 3634 unsigned long flags; 3635 u64 val; 3636 3637 /* 3638 * Disabling interrupts avoids all counter scheduling (context 3639 * switches, timer based rotation and IPIs). 3640 */ 3641 local_irq_save(flags); 3642 3643 /* If this is a per-task event, it must be for current */ 3644 WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) && 3645 event->hw.target != current); 3646 3647 /* If this is a per-CPU event, it must be for this CPU */ 3648 WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) && 3649 event->cpu != smp_processor_id()); 3650 3651 /* 3652 * It must not be an event with inherit set, we cannot read 3653 * all child counters from atomic context. 3654 */ 3655 WARN_ON_ONCE(event->attr.inherit); 3656 3657 /* 3658 * It must not have a pmu::count method, those are not 3659 * NMI safe. 3660 */ 3661 WARN_ON_ONCE(event->pmu->count); 3662 3663 /* 3664 * If the event is currently on this CPU, its either a per-task event, 3665 * or local to this CPU. Furthermore it means its ACTIVE (otherwise 3666 * oncpu == -1). 3667 */ 3668 if (event->oncpu == smp_processor_id()) 3669 event->pmu->read(event); 3670 3671 val = local64_read(&event->count); 3672 local_irq_restore(flags); 3673 3674 return val; 3675 } 3676 3677 static int perf_event_read(struct perf_event *event, bool group) 3678 { 3679 int event_cpu, ret = 0; 3680 3681 /* 3682 * If event is enabled and currently active on a CPU, update the 3683 * value in the event structure: 3684 */ 3685 if (event->state == PERF_EVENT_STATE_ACTIVE) { 3686 struct perf_read_data data = { 3687 .event = event, 3688 .group = group, 3689 .ret = 0, 3690 }; 3691 3692 event_cpu = READ_ONCE(event->oncpu); 3693 if ((unsigned)event_cpu >= nr_cpu_ids) 3694 return 0; 3695 3696 preempt_disable(); 3697 event_cpu = __perf_event_read_cpu(event, event_cpu); 3698 3699 /* 3700 * Purposely ignore the smp_call_function_single() return 3701 * value. 3702 * 3703 * If event_cpu isn't a valid CPU it means the event got 3704 * scheduled out and that will have updated the event count. 3705 * 3706 * Therefore, either way, we'll have an up-to-date event count 3707 * after this. 3708 */ 3709 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1); 3710 preempt_enable(); 3711 ret = data.ret; 3712 } else if (event->state == PERF_EVENT_STATE_INACTIVE) { 3713 struct perf_event_context *ctx = event->ctx; 3714 unsigned long flags; 3715 3716 raw_spin_lock_irqsave(&ctx->lock, flags); 3717 /* 3718 * may read while context is not active 3719 * (e.g., thread is blocked), in that case 3720 * we cannot update context time 3721 */ 3722 if (ctx->is_active) { 3723 update_context_time(ctx); 3724 update_cgrp_time_from_event(event); 3725 } 3726 if (group) 3727 update_group_times(event); 3728 else 3729 update_event_times(event); 3730 raw_spin_unlock_irqrestore(&ctx->lock, flags); 3731 } 3732 3733 return ret; 3734 } 3735 3736 /* 3737 * Initialize the perf_event context in a task_struct: 3738 */ 3739 static void __perf_event_init_context(struct perf_event_context *ctx) 3740 { 3741 raw_spin_lock_init(&ctx->lock); 3742 mutex_init(&ctx->mutex); 3743 INIT_LIST_HEAD(&ctx->active_ctx_list); 3744 INIT_LIST_HEAD(&ctx->pinned_groups); 3745 INIT_LIST_HEAD(&ctx->flexible_groups); 3746 INIT_LIST_HEAD(&ctx->event_list); 3747 atomic_set(&ctx->refcount, 1); 3748 } 3749 3750 static struct perf_event_context * 3751 alloc_perf_context(struct pmu *pmu, struct task_struct *task) 3752 { 3753 struct perf_event_context *ctx; 3754 3755 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL); 3756 if (!ctx) 3757 return NULL; 3758 3759 __perf_event_init_context(ctx); 3760 if (task) { 3761 ctx->task = task; 3762 get_task_struct(task); 3763 } 3764 ctx->pmu = pmu; 3765 3766 return ctx; 3767 } 3768 3769 static struct task_struct * 3770 find_lively_task_by_vpid(pid_t vpid) 3771 { 3772 struct task_struct *task; 3773 3774 rcu_read_lock(); 3775 if (!vpid) 3776 task = current; 3777 else 3778 task = find_task_by_vpid(vpid); 3779 if (task) 3780 get_task_struct(task); 3781 rcu_read_unlock(); 3782 3783 if (!task) 3784 return ERR_PTR(-ESRCH); 3785 3786 return task; 3787 } 3788 3789 /* 3790 * Returns a matching context with refcount and pincount. 3791 */ 3792 static struct perf_event_context * 3793 find_get_context(struct pmu *pmu, struct task_struct *task, 3794 struct perf_event *event) 3795 { 3796 struct perf_event_context *ctx, *clone_ctx = NULL; 3797 struct perf_cpu_context *cpuctx; 3798 void *task_ctx_data = NULL; 3799 unsigned long flags; 3800 int ctxn, err; 3801 int cpu = event->cpu; 3802 3803 if (!task) { 3804 /* Must be root to operate on a CPU event: */ 3805 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN)) 3806 return ERR_PTR(-EACCES); 3807 3808 /* 3809 * We could be clever and allow to attach a event to an 3810 * offline CPU and activate it when the CPU comes up, but 3811 * that's for later. 3812 */ 3813 if (!cpu_online(cpu)) 3814 return ERR_PTR(-ENODEV); 3815 3816 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 3817 ctx = &cpuctx->ctx; 3818 get_ctx(ctx); 3819 ++ctx->pin_count; 3820 3821 return ctx; 3822 } 3823 3824 err = -EINVAL; 3825 ctxn = pmu->task_ctx_nr; 3826 if (ctxn < 0) 3827 goto errout; 3828 3829 if (event->attach_state & PERF_ATTACH_TASK_DATA) { 3830 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL); 3831 if (!task_ctx_data) { 3832 err = -ENOMEM; 3833 goto errout; 3834 } 3835 } 3836 3837 retry: 3838 ctx = perf_lock_task_context(task, ctxn, &flags); 3839 if (ctx) { 3840 clone_ctx = unclone_ctx(ctx); 3841 ++ctx->pin_count; 3842 3843 if (task_ctx_data && !ctx->task_ctx_data) { 3844 ctx->task_ctx_data = task_ctx_data; 3845 task_ctx_data = NULL; 3846 } 3847 raw_spin_unlock_irqrestore(&ctx->lock, flags); 3848 3849 if (clone_ctx) 3850 put_ctx(clone_ctx); 3851 } else { 3852 ctx = alloc_perf_context(pmu, task); 3853 err = -ENOMEM; 3854 if (!ctx) 3855 goto errout; 3856 3857 if (task_ctx_data) { 3858 ctx->task_ctx_data = task_ctx_data; 3859 task_ctx_data = NULL; 3860 } 3861 3862 err = 0; 3863 mutex_lock(&task->perf_event_mutex); 3864 /* 3865 * If it has already passed perf_event_exit_task(). 3866 * we must see PF_EXITING, it takes this mutex too. 3867 */ 3868 if (task->flags & PF_EXITING) 3869 err = -ESRCH; 3870 else if (task->perf_event_ctxp[ctxn]) 3871 err = -EAGAIN; 3872 else { 3873 get_ctx(ctx); 3874 ++ctx->pin_count; 3875 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx); 3876 } 3877 mutex_unlock(&task->perf_event_mutex); 3878 3879 if (unlikely(err)) { 3880 put_ctx(ctx); 3881 3882 if (err == -EAGAIN) 3883 goto retry; 3884 goto errout; 3885 } 3886 } 3887 3888 kfree(task_ctx_data); 3889 return ctx; 3890 3891 errout: 3892 kfree(task_ctx_data); 3893 return ERR_PTR(err); 3894 } 3895 3896 static void perf_event_free_filter(struct perf_event *event); 3897 static void perf_event_free_bpf_prog(struct perf_event *event); 3898 3899 static void free_event_rcu(struct rcu_head *head) 3900 { 3901 struct perf_event *event; 3902 3903 event = container_of(head, struct perf_event, rcu_head); 3904 if (event->ns) 3905 put_pid_ns(event->ns); 3906 perf_event_free_filter(event); 3907 kfree(event); 3908 } 3909 3910 static void ring_buffer_attach(struct perf_event *event, 3911 struct ring_buffer *rb); 3912 3913 static void detach_sb_event(struct perf_event *event) 3914 { 3915 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu); 3916 3917 raw_spin_lock(&pel->lock); 3918 list_del_rcu(&event->sb_list); 3919 raw_spin_unlock(&pel->lock); 3920 } 3921 3922 static bool is_sb_event(struct perf_event *event) 3923 { 3924 struct perf_event_attr *attr = &event->attr; 3925 3926 if (event->parent) 3927 return false; 3928 3929 if (event->attach_state & PERF_ATTACH_TASK) 3930 return false; 3931 3932 if (attr->mmap || attr->mmap_data || attr->mmap2 || 3933 attr->comm || attr->comm_exec || 3934 attr->task || 3935 attr->context_switch) 3936 return true; 3937 return false; 3938 } 3939 3940 static void unaccount_pmu_sb_event(struct perf_event *event) 3941 { 3942 if (is_sb_event(event)) 3943 detach_sb_event(event); 3944 } 3945 3946 static void unaccount_event_cpu(struct perf_event *event, int cpu) 3947 { 3948 if (event->parent) 3949 return; 3950 3951 if (is_cgroup_event(event)) 3952 atomic_dec(&per_cpu(perf_cgroup_events, cpu)); 3953 } 3954 3955 #ifdef CONFIG_NO_HZ_FULL 3956 static DEFINE_SPINLOCK(nr_freq_lock); 3957 #endif 3958 3959 static void unaccount_freq_event_nohz(void) 3960 { 3961 #ifdef CONFIG_NO_HZ_FULL 3962 spin_lock(&nr_freq_lock); 3963 if (atomic_dec_and_test(&nr_freq_events)) 3964 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS); 3965 spin_unlock(&nr_freq_lock); 3966 #endif 3967 } 3968 3969 static void unaccount_freq_event(void) 3970 { 3971 if (tick_nohz_full_enabled()) 3972 unaccount_freq_event_nohz(); 3973 else 3974 atomic_dec(&nr_freq_events); 3975 } 3976 3977 static void unaccount_event(struct perf_event *event) 3978 { 3979 bool dec = false; 3980 3981 if (event->parent) 3982 return; 3983 3984 if (event->attach_state & PERF_ATTACH_TASK) 3985 dec = true; 3986 if (event->attr.mmap || event->attr.mmap_data) 3987 atomic_dec(&nr_mmap_events); 3988 if (event->attr.comm) 3989 atomic_dec(&nr_comm_events); 3990 if (event->attr.task) 3991 atomic_dec(&nr_task_events); 3992 if (event->attr.freq) 3993 unaccount_freq_event(); 3994 if (event->attr.context_switch) { 3995 dec = true; 3996 atomic_dec(&nr_switch_events); 3997 } 3998 if (is_cgroup_event(event)) 3999 dec = true; 4000 if (has_branch_stack(event)) 4001 dec = true; 4002 4003 if (dec) { 4004 if (!atomic_add_unless(&perf_sched_count, -1, 1)) 4005 schedule_delayed_work(&perf_sched_work, HZ); 4006 } 4007 4008 unaccount_event_cpu(event, event->cpu); 4009 4010 unaccount_pmu_sb_event(event); 4011 } 4012 4013 static void perf_sched_delayed(struct work_struct *work) 4014 { 4015 mutex_lock(&perf_sched_mutex); 4016 if (atomic_dec_and_test(&perf_sched_count)) 4017 static_branch_disable(&perf_sched_events); 4018 mutex_unlock(&perf_sched_mutex); 4019 } 4020 4021 /* 4022 * The following implement mutual exclusion of events on "exclusive" pmus 4023 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled 4024 * at a time, so we disallow creating events that might conflict, namely: 4025 * 4026 * 1) cpu-wide events in the presence of per-task events, 4027 * 2) per-task events in the presence of cpu-wide events, 4028 * 3) two matching events on the same context. 4029 * 4030 * The former two cases are handled in the allocation path (perf_event_alloc(), 4031 * _free_event()), the latter -- before the first perf_install_in_context(). 4032 */ 4033 static int exclusive_event_init(struct perf_event *event) 4034 { 4035 struct pmu *pmu = event->pmu; 4036 4037 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE)) 4038 return 0; 4039 4040 /* 4041 * Prevent co-existence of per-task and cpu-wide events on the 4042 * same exclusive pmu. 4043 * 4044 * Negative pmu::exclusive_cnt means there are cpu-wide 4045 * events on this "exclusive" pmu, positive means there are 4046 * per-task events. 4047 * 4048 * Since this is called in perf_event_alloc() path, event::ctx 4049 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK 4050 * to mean "per-task event", because unlike other attach states it 4051 * never gets cleared. 4052 */ 4053 if (event->attach_state & PERF_ATTACH_TASK) { 4054 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt)) 4055 return -EBUSY; 4056 } else { 4057 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt)) 4058 return -EBUSY; 4059 } 4060 4061 return 0; 4062 } 4063 4064 static void exclusive_event_destroy(struct perf_event *event) 4065 { 4066 struct pmu *pmu = event->pmu; 4067 4068 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE)) 4069 return; 4070 4071 /* see comment in exclusive_event_init() */ 4072 if (event->attach_state & PERF_ATTACH_TASK) 4073 atomic_dec(&pmu->exclusive_cnt); 4074 else 4075 atomic_inc(&pmu->exclusive_cnt); 4076 } 4077 4078 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2) 4079 { 4080 if ((e1->pmu == e2->pmu) && 4081 (e1->cpu == e2->cpu || 4082 e1->cpu == -1 || 4083 e2->cpu == -1)) 4084 return true; 4085 return false; 4086 } 4087 4088 /* Called under the same ctx::mutex as perf_install_in_context() */ 4089 static bool exclusive_event_installable(struct perf_event *event, 4090 struct perf_event_context *ctx) 4091 { 4092 struct perf_event *iter_event; 4093 struct pmu *pmu = event->pmu; 4094 4095 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE)) 4096 return true; 4097 4098 list_for_each_entry(iter_event, &ctx->event_list, event_entry) { 4099 if (exclusive_event_match(iter_event, event)) 4100 return false; 4101 } 4102 4103 return true; 4104 } 4105 4106 static void perf_addr_filters_splice(struct perf_event *event, 4107 struct list_head *head); 4108 4109 static void _free_event(struct perf_event *event) 4110 { 4111 irq_work_sync(&event->pending); 4112 4113 unaccount_event(event); 4114 4115 if (event->rb) { 4116 /* 4117 * Can happen when we close an event with re-directed output. 4118 * 4119 * Since we have a 0 refcount, perf_mmap_close() will skip 4120 * over us; possibly making our ring_buffer_put() the last. 4121 */ 4122 mutex_lock(&event->mmap_mutex); 4123 ring_buffer_attach(event, NULL); 4124 mutex_unlock(&event->mmap_mutex); 4125 } 4126 4127 if (is_cgroup_event(event)) 4128 perf_detach_cgroup(event); 4129 4130 if (!event->parent) { 4131 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) 4132 put_callchain_buffers(); 4133 } 4134 4135 perf_event_free_bpf_prog(event); 4136 perf_addr_filters_splice(event, NULL); 4137 kfree(event->addr_filters_offs); 4138 4139 if (event->destroy) 4140 event->destroy(event); 4141 4142 if (event->ctx) 4143 put_ctx(event->ctx); 4144 4145 exclusive_event_destroy(event); 4146 module_put(event->pmu->module); 4147 4148 call_rcu(&event->rcu_head, free_event_rcu); 4149 } 4150 4151 /* 4152 * Used to free events which have a known refcount of 1, such as in error paths 4153 * where the event isn't exposed yet and inherited events. 4154 */ 4155 static void free_event(struct perf_event *event) 4156 { 4157 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1, 4158 "unexpected event refcount: %ld; ptr=%p\n", 4159 atomic_long_read(&event->refcount), event)) { 4160 /* leak to avoid use-after-free */ 4161 return; 4162 } 4163 4164 _free_event(event); 4165 } 4166 4167 /* 4168 * Remove user event from the owner task. 4169 */ 4170 static void perf_remove_from_owner(struct perf_event *event) 4171 { 4172 struct task_struct *owner; 4173 4174 rcu_read_lock(); 4175 /* 4176 * Matches the smp_store_release() in perf_event_exit_task(). If we 4177 * observe !owner it means the list deletion is complete and we can 4178 * indeed free this event, otherwise we need to serialize on 4179 * owner->perf_event_mutex. 4180 */ 4181 owner = lockless_dereference(event->owner); 4182 if (owner) { 4183 /* 4184 * Since delayed_put_task_struct() also drops the last 4185 * task reference we can safely take a new reference 4186 * while holding the rcu_read_lock(). 4187 */ 4188 get_task_struct(owner); 4189 } 4190 rcu_read_unlock(); 4191 4192 if (owner) { 4193 /* 4194 * If we're here through perf_event_exit_task() we're already 4195 * holding ctx->mutex which would be an inversion wrt. the 4196 * normal lock order. 4197 * 4198 * However we can safely take this lock because its the child 4199 * ctx->mutex. 4200 */ 4201 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING); 4202 4203 /* 4204 * We have to re-check the event->owner field, if it is cleared 4205 * we raced with perf_event_exit_task(), acquiring the mutex 4206 * ensured they're done, and we can proceed with freeing the 4207 * event. 4208 */ 4209 if (event->owner) { 4210 list_del_init(&event->owner_entry); 4211 smp_store_release(&event->owner, NULL); 4212 } 4213 mutex_unlock(&owner->perf_event_mutex); 4214 put_task_struct(owner); 4215 } 4216 } 4217 4218 static void put_event(struct perf_event *event) 4219 { 4220 if (!atomic_long_dec_and_test(&event->refcount)) 4221 return; 4222 4223 _free_event(event); 4224 } 4225 4226 /* 4227 * Kill an event dead; while event:refcount will preserve the event 4228 * object, it will not preserve its functionality. Once the last 'user' 4229 * gives up the object, we'll destroy the thing. 4230 */ 4231 int perf_event_release_kernel(struct perf_event *event) 4232 { 4233 struct perf_event_context *ctx = event->ctx; 4234 struct perf_event *child, *tmp; 4235 4236 /* 4237 * If we got here through err_file: fput(event_file); we will not have 4238 * attached to a context yet. 4239 */ 4240 if (!ctx) { 4241 WARN_ON_ONCE(event->attach_state & 4242 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP)); 4243 goto no_ctx; 4244 } 4245 4246 if (!is_kernel_event(event)) 4247 perf_remove_from_owner(event); 4248 4249 ctx = perf_event_ctx_lock(event); 4250 WARN_ON_ONCE(ctx->parent_ctx); 4251 perf_remove_from_context(event, DETACH_GROUP); 4252 4253 raw_spin_lock_irq(&ctx->lock); 4254 /* 4255 * Mark this even as STATE_DEAD, there is no external reference to it 4256 * anymore. 4257 * 4258 * Anybody acquiring event->child_mutex after the below loop _must_ 4259 * also see this, most importantly inherit_event() which will avoid 4260 * placing more children on the list. 4261 * 4262 * Thus this guarantees that we will in fact observe and kill _ALL_ 4263 * child events. 4264 */ 4265 event->state = PERF_EVENT_STATE_DEAD; 4266 raw_spin_unlock_irq(&ctx->lock); 4267 4268 perf_event_ctx_unlock(event, ctx); 4269 4270 again: 4271 mutex_lock(&event->child_mutex); 4272 list_for_each_entry(child, &event->child_list, child_list) { 4273 4274 /* 4275 * Cannot change, child events are not migrated, see the 4276 * comment with perf_event_ctx_lock_nested(). 4277 */ 4278 ctx = lockless_dereference(child->ctx); 4279 /* 4280 * Since child_mutex nests inside ctx::mutex, we must jump 4281 * through hoops. We start by grabbing a reference on the ctx. 4282 * 4283 * Since the event cannot get freed while we hold the 4284 * child_mutex, the context must also exist and have a !0 4285 * reference count. 4286 */ 4287 get_ctx(ctx); 4288 4289 /* 4290 * Now that we have a ctx ref, we can drop child_mutex, and 4291 * acquire ctx::mutex without fear of it going away. Then we 4292 * can re-acquire child_mutex. 4293 */ 4294 mutex_unlock(&event->child_mutex); 4295 mutex_lock(&ctx->mutex); 4296 mutex_lock(&event->child_mutex); 4297 4298 /* 4299 * Now that we hold ctx::mutex and child_mutex, revalidate our 4300 * state, if child is still the first entry, it didn't get freed 4301 * and we can continue doing so. 4302 */ 4303 tmp = list_first_entry_or_null(&event->child_list, 4304 struct perf_event, child_list); 4305 if (tmp == child) { 4306 perf_remove_from_context(child, DETACH_GROUP); 4307 list_del(&child->child_list); 4308 free_event(child); 4309 /* 4310 * This matches the refcount bump in inherit_event(); 4311 * this can't be the last reference. 4312 */ 4313 put_event(event); 4314 } 4315 4316 mutex_unlock(&event->child_mutex); 4317 mutex_unlock(&ctx->mutex); 4318 put_ctx(ctx); 4319 goto again; 4320 } 4321 mutex_unlock(&event->child_mutex); 4322 4323 no_ctx: 4324 put_event(event); /* Must be the 'last' reference */ 4325 return 0; 4326 } 4327 EXPORT_SYMBOL_GPL(perf_event_release_kernel); 4328 4329 /* 4330 * Called when the last reference to the file is gone. 4331 */ 4332 static int perf_release(struct inode *inode, struct file *file) 4333 { 4334 perf_event_release_kernel(file->private_data); 4335 return 0; 4336 } 4337 4338 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) 4339 { 4340 struct perf_event *child; 4341 u64 total = 0; 4342 4343 *enabled = 0; 4344 *running = 0; 4345 4346 mutex_lock(&event->child_mutex); 4347 4348 (void)perf_event_read(event, false); 4349 total += perf_event_count(event); 4350 4351 *enabled += event->total_time_enabled + 4352 atomic64_read(&event->child_total_time_enabled); 4353 *running += event->total_time_running + 4354 atomic64_read(&event->child_total_time_running); 4355 4356 list_for_each_entry(child, &event->child_list, child_list) { 4357 (void)perf_event_read(child, false); 4358 total += perf_event_count(child); 4359 *enabled += child->total_time_enabled; 4360 *running += child->total_time_running; 4361 } 4362 mutex_unlock(&event->child_mutex); 4363 4364 return total; 4365 } 4366 EXPORT_SYMBOL_GPL(perf_event_read_value); 4367 4368 static int __perf_read_group_add(struct perf_event *leader, 4369 u64 read_format, u64 *values) 4370 { 4371 struct perf_event *sub; 4372 int n = 1; /* skip @nr */ 4373 int ret; 4374 4375 ret = perf_event_read(leader, true); 4376 if (ret) 4377 return ret; 4378 4379 /* 4380 * Since we co-schedule groups, {enabled,running} times of siblings 4381 * will be identical to those of the leader, so we only publish one 4382 * set. 4383 */ 4384 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { 4385 values[n++] += leader->total_time_enabled + 4386 atomic64_read(&leader->child_total_time_enabled); 4387 } 4388 4389 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { 4390 values[n++] += leader->total_time_running + 4391 atomic64_read(&leader->child_total_time_running); 4392 } 4393 4394 /* 4395 * Write {count,id} tuples for every sibling. 4396 */ 4397 values[n++] += perf_event_count(leader); 4398 if (read_format & PERF_FORMAT_ID) 4399 values[n++] = primary_event_id(leader); 4400 4401 list_for_each_entry(sub, &leader->sibling_list, group_entry) { 4402 values[n++] += perf_event_count(sub); 4403 if (read_format & PERF_FORMAT_ID) 4404 values[n++] = primary_event_id(sub); 4405 } 4406 4407 return 0; 4408 } 4409 4410 static int perf_read_group(struct perf_event *event, 4411 u64 read_format, char __user *buf) 4412 { 4413 struct perf_event *leader = event->group_leader, *child; 4414 struct perf_event_context *ctx = leader->ctx; 4415 int ret; 4416 u64 *values; 4417 4418 lockdep_assert_held(&ctx->mutex); 4419 4420 values = kzalloc(event->read_size, GFP_KERNEL); 4421 if (!values) 4422 return -ENOMEM; 4423 4424 values[0] = 1 + leader->nr_siblings; 4425 4426 /* 4427 * By locking the child_mutex of the leader we effectively 4428 * lock the child list of all siblings.. XXX explain how. 4429 */ 4430 mutex_lock(&leader->child_mutex); 4431 4432 ret = __perf_read_group_add(leader, read_format, values); 4433 if (ret) 4434 goto unlock; 4435 4436 list_for_each_entry(child, &leader->child_list, child_list) { 4437 ret = __perf_read_group_add(child, read_format, values); 4438 if (ret) 4439 goto unlock; 4440 } 4441 4442 mutex_unlock(&leader->child_mutex); 4443 4444 ret = event->read_size; 4445 if (copy_to_user(buf, values, event->read_size)) 4446 ret = -EFAULT; 4447 goto out; 4448 4449 unlock: 4450 mutex_unlock(&leader->child_mutex); 4451 out: 4452 kfree(values); 4453 return ret; 4454 } 4455 4456 static int perf_read_one(struct perf_event *event, 4457 u64 read_format, char __user *buf) 4458 { 4459 u64 enabled, running; 4460 u64 values[4]; 4461 int n = 0; 4462 4463 values[n++] = perf_event_read_value(event, &enabled, &running); 4464 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 4465 values[n++] = enabled; 4466 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 4467 values[n++] = running; 4468 if (read_format & PERF_FORMAT_ID) 4469 values[n++] = primary_event_id(event); 4470 4471 if (copy_to_user(buf, values, n * sizeof(u64))) 4472 return -EFAULT; 4473 4474 return n * sizeof(u64); 4475 } 4476 4477 static bool is_event_hup(struct perf_event *event) 4478 { 4479 bool no_children; 4480 4481 if (event->state > PERF_EVENT_STATE_EXIT) 4482 return false; 4483 4484 mutex_lock(&event->child_mutex); 4485 no_children = list_empty(&event->child_list); 4486 mutex_unlock(&event->child_mutex); 4487 return no_children; 4488 } 4489 4490 /* 4491 * Read the performance event - simple non blocking version for now 4492 */ 4493 static ssize_t 4494 __perf_read(struct perf_event *event, char __user *buf, size_t count) 4495 { 4496 u64 read_format = event->attr.read_format; 4497 int ret; 4498 4499 /* 4500 * Return end-of-file for a read on a event that is in 4501 * error state (i.e. because it was pinned but it couldn't be 4502 * scheduled on to the CPU at some point). 4503 */ 4504 if (event->state == PERF_EVENT_STATE_ERROR) 4505 return 0; 4506 4507 if (count < event->read_size) 4508 return -ENOSPC; 4509 4510 WARN_ON_ONCE(event->ctx->parent_ctx); 4511 if (read_format & PERF_FORMAT_GROUP) 4512 ret = perf_read_group(event, read_format, buf); 4513 else 4514 ret = perf_read_one(event, read_format, buf); 4515 4516 return ret; 4517 } 4518 4519 static ssize_t 4520 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 4521 { 4522 struct perf_event *event = file->private_data; 4523 struct perf_event_context *ctx; 4524 int ret; 4525 4526 ctx = perf_event_ctx_lock(event); 4527 ret = __perf_read(event, buf, count); 4528 perf_event_ctx_unlock(event, ctx); 4529 4530 return ret; 4531 } 4532 4533 static unsigned int perf_poll(struct file *file, poll_table *wait) 4534 { 4535 struct perf_event *event = file->private_data; 4536 struct ring_buffer *rb; 4537 unsigned int events = POLLHUP; 4538 4539 poll_wait(file, &event->waitq, wait); 4540 4541 if (is_event_hup(event)) 4542 return events; 4543 4544 /* 4545 * Pin the event->rb by taking event->mmap_mutex; otherwise 4546 * perf_event_set_output() can swizzle our rb and make us miss wakeups. 4547 */ 4548 mutex_lock(&event->mmap_mutex); 4549 rb = event->rb; 4550 if (rb) 4551 events = atomic_xchg(&rb->poll, 0); 4552 mutex_unlock(&event->mmap_mutex); 4553 return events; 4554 } 4555 4556 static void _perf_event_reset(struct perf_event *event) 4557 { 4558 (void)perf_event_read(event, false); 4559 local64_set(&event->count, 0); 4560 perf_event_update_userpage(event); 4561 } 4562 4563 /* 4564 * Holding the top-level event's child_mutex means that any 4565 * descendant process that has inherited this event will block 4566 * in perf_event_exit_event() if it goes to exit, thus satisfying the 4567 * task existence requirements of perf_event_enable/disable. 4568 */ 4569 static void perf_event_for_each_child(struct perf_event *event, 4570 void (*func)(struct perf_event *)) 4571 { 4572 struct perf_event *child; 4573 4574 WARN_ON_ONCE(event->ctx->parent_ctx); 4575 4576 mutex_lock(&event->child_mutex); 4577 func(event); 4578 list_for_each_entry(child, &event->child_list, child_list) 4579 func(child); 4580 mutex_unlock(&event->child_mutex); 4581 } 4582 4583 static void perf_event_for_each(struct perf_event *event, 4584 void (*func)(struct perf_event *)) 4585 { 4586 struct perf_event_context *ctx = event->ctx; 4587 struct perf_event *sibling; 4588 4589 lockdep_assert_held(&ctx->mutex); 4590 4591 event = event->group_leader; 4592 4593 perf_event_for_each_child(event, func); 4594 list_for_each_entry(sibling, &event->sibling_list, group_entry) 4595 perf_event_for_each_child(sibling, func); 4596 } 4597 4598 static void __perf_event_period(struct perf_event *event, 4599 struct perf_cpu_context *cpuctx, 4600 struct perf_event_context *ctx, 4601 void *info) 4602 { 4603 u64 value = *((u64 *)info); 4604 bool active; 4605 4606 if (event->attr.freq) { 4607 event->attr.sample_freq = value; 4608 } else { 4609 event->attr.sample_period = value; 4610 event->hw.sample_period = value; 4611 } 4612 4613 active = (event->state == PERF_EVENT_STATE_ACTIVE); 4614 if (active) { 4615 perf_pmu_disable(ctx->pmu); 4616 /* 4617 * We could be throttled; unthrottle now to avoid the tick 4618 * trying to unthrottle while we already re-started the event. 4619 */ 4620 if (event->hw.interrupts == MAX_INTERRUPTS) { 4621 event->hw.interrupts = 0; 4622 perf_log_throttle(event, 1); 4623 } 4624 event->pmu->stop(event, PERF_EF_UPDATE); 4625 } 4626 4627 local64_set(&event->hw.period_left, 0); 4628 4629 if (active) { 4630 event->pmu->start(event, PERF_EF_RELOAD); 4631 perf_pmu_enable(ctx->pmu); 4632 } 4633 } 4634 4635 static int perf_event_period(struct perf_event *event, u64 __user *arg) 4636 { 4637 u64 value; 4638 4639 if (!is_sampling_event(event)) 4640 return -EINVAL; 4641 4642 if (copy_from_user(&value, arg, sizeof(value))) 4643 return -EFAULT; 4644 4645 if (!value) 4646 return -EINVAL; 4647 4648 if (event->attr.freq && value > sysctl_perf_event_sample_rate) 4649 return -EINVAL; 4650 4651 event_function_call(event, __perf_event_period, &value); 4652 4653 return 0; 4654 } 4655 4656 static const struct file_operations perf_fops; 4657 4658 static inline int perf_fget_light(int fd, struct fd *p) 4659 { 4660 struct fd f = fdget(fd); 4661 if (!f.file) 4662 return -EBADF; 4663 4664 if (f.file->f_op != &perf_fops) { 4665 fdput(f); 4666 return -EBADF; 4667 } 4668 *p = f; 4669 return 0; 4670 } 4671 4672 static int perf_event_set_output(struct perf_event *event, 4673 struct perf_event *output_event); 4674 static int perf_event_set_filter(struct perf_event *event, void __user *arg); 4675 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd); 4676 4677 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg) 4678 { 4679 void (*func)(struct perf_event *); 4680 u32 flags = arg; 4681 4682 switch (cmd) { 4683 case PERF_EVENT_IOC_ENABLE: 4684 func = _perf_event_enable; 4685 break; 4686 case PERF_EVENT_IOC_DISABLE: 4687 func = _perf_event_disable; 4688 break; 4689 case PERF_EVENT_IOC_RESET: 4690 func = _perf_event_reset; 4691 break; 4692 4693 case PERF_EVENT_IOC_REFRESH: 4694 return _perf_event_refresh(event, arg); 4695 4696 case PERF_EVENT_IOC_PERIOD: 4697 return perf_event_period(event, (u64 __user *)arg); 4698 4699 case PERF_EVENT_IOC_ID: 4700 { 4701 u64 id = primary_event_id(event); 4702 4703 if (copy_to_user((void __user *)arg, &id, sizeof(id))) 4704 return -EFAULT; 4705 return 0; 4706 } 4707 4708 case PERF_EVENT_IOC_SET_OUTPUT: 4709 { 4710 int ret; 4711 if (arg != -1) { 4712 struct perf_event *output_event; 4713 struct fd output; 4714 ret = perf_fget_light(arg, &output); 4715 if (ret) 4716 return ret; 4717 output_event = output.file->private_data; 4718 ret = perf_event_set_output(event, output_event); 4719 fdput(output); 4720 } else { 4721 ret = perf_event_set_output(event, NULL); 4722 } 4723 return ret; 4724 } 4725 4726 case PERF_EVENT_IOC_SET_FILTER: 4727 return perf_event_set_filter(event, (void __user *)arg); 4728 4729 case PERF_EVENT_IOC_SET_BPF: 4730 return perf_event_set_bpf_prog(event, arg); 4731 4732 case PERF_EVENT_IOC_PAUSE_OUTPUT: { 4733 struct ring_buffer *rb; 4734 4735 rcu_read_lock(); 4736 rb = rcu_dereference(event->rb); 4737 if (!rb || !rb->nr_pages) { 4738 rcu_read_unlock(); 4739 return -EINVAL; 4740 } 4741 rb_toggle_paused(rb, !!arg); 4742 rcu_read_unlock(); 4743 return 0; 4744 } 4745 default: 4746 return -ENOTTY; 4747 } 4748 4749 if (flags & PERF_IOC_FLAG_GROUP) 4750 perf_event_for_each(event, func); 4751 else 4752 perf_event_for_each_child(event, func); 4753 4754 return 0; 4755 } 4756 4757 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 4758 { 4759 struct perf_event *event = file->private_data; 4760 struct perf_event_context *ctx; 4761 long ret; 4762 4763 ctx = perf_event_ctx_lock(event); 4764 ret = _perf_ioctl(event, cmd, arg); 4765 perf_event_ctx_unlock(event, ctx); 4766 4767 return ret; 4768 } 4769 4770 #ifdef CONFIG_COMPAT 4771 static long perf_compat_ioctl(struct file *file, unsigned int cmd, 4772 unsigned long arg) 4773 { 4774 switch (_IOC_NR(cmd)) { 4775 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER): 4776 case _IOC_NR(PERF_EVENT_IOC_ID): 4777 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */ 4778 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) { 4779 cmd &= ~IOCSIZE_MASK; 4780 cmd |= sizeof(void *) << IOCSIZE_SHIFT; 4781 } 4782 break; 4783 } 4784 return perf_ioctl(file, cmd, arg); 4785 } 4786 #else 4787 # define perf_compat_ioctl NULL 4788 #endif 4789 4790 int perf_event_task_enable(void) 4791 { 4792 struct perf_event_context *ctx; 4793 struct perf_event *event; 4794 4795 mutex_lock(¤t->perf_event_mutex); 4796 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { 4797 ctx = perf_event_ctx_lock(event); 4798 perf_event_for_each_child(event, _perf_event_enable); 4799 perf_event_ctx_unlock(event, ctx); 4800 } 4801 mutex_unlock(¤t->perf_event_mutex); 4802 4803 return 0; 4804 } 4805 4806 int perf_event_task_disable(void) 4807 { 4808 struct perf_event_context *ctx; 4809 struct perf_event *event; 4810 4811 mutex_lock(¤t->perf_event_mutex); 4812 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { 4813 ctx = perf_event_ctx_lock(event); 4814 perf_event_for_each_child(event, _perf_event_disable); 4815 perf_event_ctx_unlock(event, ctx); 4816 } 4817 mutex_unlock(¤t->perf_event_mutex); 4818 4819 return 0; 4820 } 4821 4822 static int perf_event_index(struct perf_event *event) 4823 { 4824 if (event->hw.state & PERF_HES_STOPPED) 4825 return 0; 4826 4827 if (event->state != PERF_EVENT_STATE_ACTIVE) 4828 return 0; 4829 4830 return event->pmu->event_idx(event); 4831 } 4832 4833 static void calc_timer_values(struct perf_event *event, 4834 u64 *now, 4835 u64 *enabled, 4836 u64 *running) 4837 { 4838 u64 ctx_time; 4839 4840 *now = perf_clock(); 4841 ctx_time = event->shadow_ctx_time + *now; 4842 *enabled = ctx_time - event->tstamp_enabled; 4843 *running = ctx_time - event->tstamp_running; 4844 } 4845 4846 static void perf_event_init_userpage(struct perf_event *event) 4847 { 4848 struct perf_event_mmap_page *userpg; 4849 struct ring_buffer *rb; 4850 4851 rcu_read_lock(); 4852 rb = rcu_dereference(event->rb); 4853 if (!rb) 4854 goto unlock; 4855 4856 userpg = rb->user_page; 4857 4858 /* Allow new userspace to detect that bit 0 is deprecated */ 4859 userpg->cap_bit0_is_deprecated = 1; 4860 userpg->size = offsetof(struct perf_event_mmap_page, __reserved); 4861 userpg->data_offset = PAGE_SIZE; 4862 userpg->data_size = perf_data_size(rb); 4863 4864 unlock: 4865 rcu_read_unlock(); 4866 } 4867 4868 void __weak arch_perf_update_userpage( 4869 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now) 4870 { 4871 } 4872 4873 /* 4874 * Callers need to ensure there can be no nesting of this function, otherwise 4875 * the seqlock logic goes bad. We can not serialize this because the arch 4876 * code calls this from NMI context. 4877 */ 4878 void perf_event_update_userpage(struct perf_event *event) 4879 { 4880 struct perf_event_mmap_page *userpg; 4881 struct ring_buffer *rb; 4882 u64 enabled, running, now; 4883 4884 rcu_read_lock(); 4885 rb = rcu_dereference(event->rb); 4886 if (!rb) 4887 goto unlock; 4888 4889 /* 4890 * compute total_time_enabled, total_time_running 4891 * based on snapshot values taken when the event 4892 * was last scheduled in. 4893 * 4894 * we cannot simply called update_context_time() 4895 * because of locking issue as we can be called in 4896 * NMI context 4897 */ 4898 calc_timer_values(event, &now, &enabled, &running); 4899 4900 userpg = rb->user_page; 4901 /* 4902 * Disable preemption so as to not let the corresponding user-space 4903 * spin too long if we get preempted. 4904 */ 4905 preempt_disable(); 4906 ++userpg->lock; 4907 barrier(); 4908 userpg->index = perf_event_index(event); 4909 userpg->offset = perf_event_count(event); 4910 if (userpg->index) 4911 userpg->offset -= local64_read(&event->hw.prev_count); 4912 4913 userpg->time_enabled = enabled + 4914 atomic64_read(&event->child_total_time_enabled); 4915 4916 userpg->time_running = running + 4917 atomic64_read(&event->child_total_time_running); 4918 4919 arch_perf_update_userpage(event, userpg, now); 4920 4921 barrier(); 4922 ++userpg->lock; 4923 preempt_enable(); 4924 unlock: 4925 rcu_read_unlock(); 4926 } 4927 4928 static int perf_mmap_fault(struct vm_fault *vmf) 4929 { 4930 struct perf_event *event = vmf->vma->vm_file->private_data; 4931 struct ring_buffer *rb; 4932 int ret = VM_FAULT_SIGBUS; 4933 4934 if (vmf->flags & FAULT_FLAG_MKWRITE) { 4935 if (vmf->pgoff == 0) 4936 ret = 0; 4937 return ret; 4938 } 4939 4940 rcu_read_lock(); 4941 rb = rcu_dereference(event->rb); 4942 if (!rb) 4943 goto unlock; 4944 4945 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE)) 4946 goto unlock; 4947 4948 vmf->page = perf_mmap_to_page(rb, vmf->pgoff); 4949 if (!vmf->page) 4950 goto unlock; 4951 4952 get_page(vmf->page); 4953 vmf->page->mapping = vmf->vma->vm_file->f_mapping; 4954 vmf->page->index = vmf->pgoff; 4955 4956 ret = 0; 4957 unlock: 4958 rcu_read_unlock(); 4959 4960 return ret; 4961 } 4962 4963 static void ring_buffer_attach(struct perf_event *event, 4964 struct ring_buffer *rb) 4965 { 4966 struct ring_buffer *old_rb = NULL; 4967 unsigned long flags; 4968 4969 if (event->rb) { 4970 /* 4971 * Should be impossible, we set this when removing 4972 * event->rb_entry and wait/clear when adding event->rb_entry. 4973 */ 4974 WARN_ON_ONCE(event->rcu_pending); 4975 4976 old_rb = event->rb; 4977 spin_lock_irqsave(&old_rb->event_lock, flags); 4978 list_del_rcu(&event->rb_entry); 4979 spin_unlock_irqrestore(&old_rb->event_lock, flags); 4980 4981 event->rcu_batches = get_state_synchronize_rcu(); 4982 event->rcu_pending = 1; 4983 } 4984 4985 if (rb) { 4986 if (event->rcu_pending) { 4987 cond_synchronize_rcu(event->rcu_batches); 4988 event->rcu_pending = 0; 4989 } 4990 4991 spin_lock_irqsave(&rb->event_lock, flags); 4992 list_add_rcu(&event->rb_entry, &rb->event_list); 4993 spin_unlock_irqrestore(&rb->event_lock, flags); 4994 } 4995 4996 /* 4997 * Avoid racing with perf_mmap_close(AUX): stop the event 4998 * before swizzling the event::rb pointer; if it's getting 4999 * unmapped, its aux_mmap_count will be 0 and it won't 5000 * restart. See the comment in __perf_pmu_output_stop(). 5001 * 5002 * Data will inevitably be lost when set_output is done in 5003 * mid-air, but then again, whoever does it like this is 5004 * not in for the data anyway. 5005 */ 5006 if (has_aux(event)) 5007 perf_event_stop(event, 0); 5008 5009 rcu_assign_pointer(event->rb, rb); 5010 5011 if (old_rb) { 5012 ring_buffer_put(old_rb); 5013 /* 5014 * Since we detached before setting the new rb, so that we 5015 * could attach the new rb, we could have missed a wakeup. 5016 * Provide it now. 5017 */ 5018 wake_up_all(&event->waitq); 5019 } 5020 } 5021 5022 static void ring_buffer_wakeup(struct perf_event *event) 5023 { 5024 struct ring_buffer *rb; 5025 5026 rcu_read_lock(); 5027 rb = rcu_dereference(event->rb); 5028 if (rb) { 5029 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) 5030 wake_up_all(&event->waitq); 5031 } 5032 rcu_read_unlock(); 5033 } 5034 5035 struct ring_buffer *ring_buffer_get(struct perf_event *event) 5036 { 5037 struct ring_buffer *rb; 5038 5039 rcu_read_lock(); 5040 rb = rcu_dereference(event->rb); 5041 if (rb) { 5042 if (!atomic_inc_not_zero(&rb->refcount)) 5043 rb = NULL; 5044 } 5045 rcu_read_unlock(); 5046 5047 return rb; 5048 } 5049 5050 void ring_buffer_put(struct ring_buffer *rb) 5051 { 5052 if (!atomic_dec_and_test(&rb->refcount)) 5053 return; 5054 5055 WARN_ON_ONCE(!list_empty(&rb->event_list)); 5056 5057 call_rcu(&rb->rcu_head, rb_free_rcu); 5058 } 5059 5060 static void perf_mmap_open(struct vm_area_struct *vma) 5061 { 5062 struct perf_event *event = vma->vm_file->private_data; 5063 5064 atomic_inc(&event->mmap_count); 5065 atomic_inc(&event->rb->mmap_count); 5066 5067 if (vma->vm_pgoff) 5068 atomic_inc(&event->rb->aux_mmap_count); 5069 5070 if (event->pmu->event_mapped) 5071 event->pmu->event_mapped(event); 5072 } 5073 5074 static void perf_pmu_output_stop(struct perf_event *event); 5075 5076 /* 5077 * A buffer can be mmap()ed multiple times; either directly through the same 5078 * event, or through other events by use of perf_event_set_output(). 5079 * 5080 * In order to undo the VM accounting done by perf_mmap() we need to destroy 5081 * the buffer here, where we still have a VM context. This means we need 5082 * to detach all events redirecting to us. 5083 */ 5084 static void perf_mmap_close(struct vm_area_struct *vma) 5085 { 5086 struct perf_event *event = vma->vm_file->private_data; 5087 5088 struct ring_buffer *rb = ring_buffer_get(event); 5089 struct user_struct *mmap_user = rb->mmap_user; 5090 int mmap_locked = rb->mmap_locked; 5091 unsigned long size = perf_data_size(rb); 5092 5093 if (event->pmu->event_unmapped) 5094 event->pmu->event_unmapped(event); 5095 5096 /* 5097 * rb->aux_mmap_count will always drop before rb->mmap_count and 5098 * event->mmap_count, so it is ok to use event->mmap_mutex to 5099 * serialize with perf_mmap here. 5100 */ 5101 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff && 5102 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) { 5103 /* 5104 * Stop all AUX events that are writing to this buffer, 5105 * so that we can free its AUX pages and corresponding PMU 5106 * data. Note that after rb::aux_mmap_count dropped to zero, 5107 * they won't start any more (see perf_aux_output_begin()). 5108 */ 5109 perf_pmu_output_stop(event); 5110 5111 /* now it's safe to free the pages */ 5112 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm); 5113 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked; 5114 5115 /* this has to be the last one */ 5116 rb_free_aux(rb); 5117 WARN_ON_ONCE(atomic_read(&rb->aux_refcount)); 5118 5119 mutex_unlock(&event->mmap_mutex); 5120 } 5121 5122 atomic_dec(&rb->mmap_count); 5123 5124 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) 5125 goto out_put; 5126 5127 ring_buffer_attach(event, NULL); 5128 mutex_unlock(&event->mmap_mutex); 5129 5130 /* If there's still other mmap()s of this buffer, we're done. */ 5131 if (atomic_read(&rb->mmap_count)) 5132 goto out_put; 5133 5134 /* 5135 * No other mmap()s, detach from all other events that might redirect 5136 * into the now unreachable buffer. Somewhat complicated by the 5137 * fact that rb::event_lock otherwise nests inside mmap_mutex. 5138 */ 5139 again: 5140 rcu_read_lock(); 5141 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) { 5142 if (!atomic_long_inc_not_zero(&event->refcount)) { 5143 /* 5144 * This event is en-route to free_event() which will 5145 * detach it and remove it from the list. 5146 */ 5147 continue; 5148 } 5149 rcu_read_unlock(); 5150 5151 mutex_lock(&event->mmap_mutex); 5152 /* 5153 * Check we didn't race with perf_event_set_output() which can 5154 * swizzle the rb from under us while we were waiting to 5155 * acquire mmap_mutex. 5156 * 5157 * If we find a different rb; ignore this event, a next 5158 * iteration will no longer find it on the list. We have to 5159 * still restart the iteration to make sure we're not now 5160 * iterating the wrong list. 5161 */ 5162 if (event->rb == rb) 5163 ring_buffer_attach(event, NULL); 5164 5165 mutex_unlock(&event->mmap_mutex); 5166 put_event(event); 5167 5168 /* 5169 * Restart the iteration; either we're on the wrong list or 5170 * destroyed its integrity by doing a deletion. 5171 */ 5172 goto again; 5173 } 5174 rcu_read_unlock(); 5175 5176 /* 5177 * It could be there's still a few 0-ref events on the list; they'll 5178 * get cleaned up by free_event() -- they'll also still have their 5179 * ref on the rb and will free it whenever they are done with it. 5180 * 5181 * Aside from that, this buffer is 'fully' detached and unmapped, 5182 * undo the VM accounting. 5183 */ 5184 5185 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm); 5186 vma->vm_mm->pinned_vm -= mmap_locked; 5187 free_uid(mmap_user); 5188 5189 out_put: 5190 ring_buffer_put(rb); /* could be last */ 5191 } 5192 5193 static const struct vm_operations_struct perf_mmap_vmops = { 5194 .open = perf_mmap_open, 5195 .close = perf_mmap_close, /* non mergable */ 5196 .fault = perf_mmap_fault, 5197 .page_mkwrite = perf_mmap_fault, 5198 }; 5199 5200 static int perf_mmap(struct file *file, struct vm_area_struct *vma) 5201 { 5202 struct perf_event *event = file->private_data; 5203 unsigned long user_locked, user_lock_limit; 5204 struct user_struct *user = current_user(); 5205 unsigned long locked, lock_limit; 5206 struct ring_buffer *rb = NULL; 5207 unsigned long vma_size; 5208 unsigned long nr_pages; 5209 long user_extra = 0, extra = 0; 5210 int ret = 0, flags = 0; 5211 5212 /* 5213 * Don't allow mmap() of inherited per-task counters. This would 5214 * create a performance issue due to all children writing to the 5215 * same rb. 5216 */ 5217 if (event->cpu == -1 && event->attr.inherit) 5218 return -EINVAL; 5219 5220 if (!(vma->vm_flags & VM_SHARED)) 5221 return -EINVAL; 5222 5223 vma_size = vma->vm_end - vma->vm_start; 5224 5225 if (vma->vm_pgoff == 0) { 5226 nr_pages = (vma_size / PAGE_SIZE) - 1; 5227 } else { 5228 /* 5229 * AUX area mapping: if rb->aux_nr_pages != 0, it's already 5230 * mapped, all subsequent mappings should have the same size 5231 * and offset. Must be above the normal perf buffer. 5232 */ 5233 u64 aux_offset, aux_size; 5234 5235 if (!event->rb) 5236 return -EINVAL; 5237 5238 nr_pages = vma_size / PAGE_SIZE; 5239 5240 mutex_lock(&event->mmap_mutex); 5241 ret = -EINVAL; 5242 5243 rb = event->rb; 5244 if (!rb) 5245 goto aux_unlock; 5246 5247 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset); 5248 aux_size = ACCESS_ONCE(rb->user_page->aux_size); 5249 5250 if (aux_offset < perf_data_size(rb) + PAGE_SIZE) 5251 goto aux_unlock; 5252 5253 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT) 5254 goto aux_unlock; 5255 5256 /* already mapped with a different offset */ 5257 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff) 5258 goto aux_unlock; 5259 5260 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE) 5261 goto aux_unlock; 5262 5263 /* already mapped with a different size */ 5264 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages) 5265 goto aux_unlock; 5266 5267 if (!is_power_of_2(nr_pages)) 5268 goto aux_unlock; 5269 5270 if (!atomic_inc_not_zero(&rb->mmap_count)) 5271 goto aux_unlock; 5272 5273 if (rb_has_aux(rb)) { 5274 atomic_inc(&rb->aux_mmap_count); 5275 ret = 0; 5276 goto unlock; 5277 } 5278 5279 atomic_set(&rb->aux_mmap_count, 1); 5280 user_extra = nr_pages; 5281 5282 goto accounting; 5283 } 5284 5285 /* 5286 * If we have rb pages ensure they're a power-of-two number, so we 5287 * can do bitmasks instead of modulo. 5288 */ 5289 if (nr_pages != 0 && !is_power_of_2(nr_pages)) 5290 return -EINVAL; 5291 5292 if (vma_size != PAGE_SIZE * (1 + nr_pages)) 5293 return -EINVAL; 5294 5295 WARN_ON_ONCE(event->ctx->parent_ctx); 5296 again: 5297 mutex_lock(&event->mmap_mutex); 5298 if (event->rb) { 5299 if (event->rb->nr_pages != nr_pages) { 5300 ret = -EINVAL; 5301 goto unlock; 5302 } 5303 5304 if (!atomic_inc_not_zero(&event->rb->mmap_count)) { 5305 /* 5306 * Raced against perf_mmap_close() through 5307 * perf_event_set_output(). Try again, hope for better 5308 * luck. 5309 */ 5310 mutex_unlock(&event->mmap_mutex); 5311 goto again; 5312 } 5313 5314 goto unlock; 5315 } 5316 5317 user_extra = nr_pages + 1; 5318 5319 accounting: 5320 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10); 5321 5322 /* 5323 * Increase the limit linearly with more CPUs: 5324 */ 5325 user_lock_limit *= num_online_cpus(); 5326 5327 user_locked = atomic_long_read(&user->locked_vm) + user_extra; 5328 5329 if (user_locked > user_lock_limit) 5330 extra = user_locked - user_lock_limit; 5331 5332 lock_limit = rlimit(RLIMIT_MEMLOCK); 5333 lock_limit >>= PAGE_SHIFT; 5334 locked = vma->vm_mm->pinned_vm + extra; 5335 5336 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() && 5337 !capable(CAP_IPC_LOCK)) { 5338 ret = -EPERM; 5339 goto unlock; 5340 } 5341 5342 WARN_ON(!rb && event->rb); 5343 5344 if (vma->vm_flags & VM_WRITE) 5345 flags |= RING_BUFFER_WRITABLE; 5346 5347 if (!rb) { 5348 rb = rb_alloc(nr_pages, 5349 event->attr.watermark ? event->attr.wakeup_watermark : 0, 5350 event->cpu, flags); 5351 5352 if (!rb) { 5353 ret = -ENOMEM; 5354 goto unlock; 5355 } 5356 5357 atomic_set(&rb->mmap_count, 1); 5358 rb->mmap_user = get_current_user(); 5359 rb->mmap_locked = extra; 5360 5361 ring_buffer_attach(event, rb); 5362 5363 perf_event_init_userpage(event); 5364 perf_event_update_userpage(event); 5365 } else { 5366 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages, 5367 event->attr.aux_watermark, flags); 5368 if (!ret) 5369 rb->aux_mmap_locked = extra; 5370 } 5371 5372 unlock: 5373 if (!ret) { 5374 atomic_long_add(user_extra, &user->locked_vm); 5375 vma->vm_mm->pinned_vm += extra; 5376 5377 atomic_inc(&event->mmap_count); 5378 } else if (rb) { 5379 atomic_dec(&rb->mmap_count); 5380 } 5381 aux_unlock: 5382 mutex_unlock(&event->mmap_mutex); 5383 5384 /* 5385 * Since pinned accounting is per vm we cannot allow fork() to copy our 5386 * vma. 5387 */ 5388 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP; 5389 vma->vm_ops = &perf_mmap_vmops; 5390 5391 if (event->pmu->event_mapped) 5392 event->pmu->event_mapped(event); 5393 5394 return ret; 5395 } 5396 5397 static int perf_fasync(int fd, struct file *filp, int on) 5398 { 5399 struct inode *inode = file_inode(filp); 5400 struct perf_event *event = filp->private_data; 5401 int retval; 5402 5403 inode_lock(inode); 5404 retval = fasync_helper(fd, filp, on, &event->fasync); 5405 inode_unlock(inode); 5406 5407 if (retval < 0) 5408 return retval; 5409 5410 return 0; 5411 } 5412 5413 static const struct file_operations perf_fops = { 5414 .llseek = no_llseek, 5415 .release = perf_release, 5416 .read = perf_read, 5417 .poll = perf_poll, 5418 .unlocked_ioctl = perf_ioctl, 5419 .compat_ioctl = perf_compat_ioctl, 5420 .mmap = perf_mmap, 5421 .fasync = perf_fasync, 5422 }; 5423 5424 /* 5425 * Perf event wakeup 5426 * 5427 * If there's data, ensure we set the poll() state and publish everything 5428 * to user-space before waking everybody up. 5429 */ 5430 5431 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event) 5432 { 5433 /* only the parent has fasync state */ 5434 if (event->parent) 5435 event = event->parent; 5436 return &event->fasync; 5437 } 5438 5439 void perf_event_wakeup(struct perf_event *event) 5440 { 5441 ring_buffer_wakeup(event); 5442 5443 if (event->pending_kill) { 5444 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill); 5445 event->pending_kill = 0; 5446 } 5447 } 5448 5449 static void perf_pending_event(struct irq_work *entry) 5450 { 5451 struct perf_event *event = container_of(entry, 5452 struct perf_event, pending); 5453 int rctx; 5454 5455 rctx = perf_swevent_get_recursion_context(); 5456 /* 5457 * If we 'fail' here, that's OK, it means recursion is already disabled 5458 * and we won't recurse 'further'. 5459 */ 5460 5461 if (event->pending_disable) { 5462 event->pending_disable = 0; 5463 perf_event_disable_local(event); 5464 } 5465 5466 if (event->pending_wakeup) { 5467 event->pending_wakeup = 0; 5468 perf_event_wakeup(event); 5469 } 5470 5471 if (rctx >= 0) 5472 perf_swevent_put_recursion_context(rctx); 5473 } 5474 5475 /* 5476 * We assume there is only KVM supporting the callbacks. 5477 * Later on, we might change it to a list if there is 5478 * another virtualization implementation supporting the callbacks. 5479 */ 5480 struct perf_guest_info_callbacks *perf_guest_cbs; 5481 5482 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) 5483 { 5484 perf_guest_cbs = cbs; 5485 return 0; 5486 } 5487 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks); 5488 5489 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) 5490 { 5491 perf_guest_cbs = NULL; 5492 return 0; 5493 } 5494 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks); 5495 5496 static void 5497 perf_output_sample_regs(struct perf_output_handle *handle, 5498 struct pt_regs *regs, u64 mask) 5499 { 5500 int bit; 5501 DECLARE_BITMAP(_mask, 64); 5502 5503 bitmap_from_u64(_mask, mask); 5504 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) { 5505 u64 val; 5506 5507 val = perf_reg_value(regs, bit); 5508 perf_output_put(handle, val); 5509 } 5510 } 5511 5512 static void perf_sample_regs_user(struct perf_regs *regs_user, 5513 struct pt_regs *regs, 5514 struct pt_regs *regs_user_copy) 5515 { 5516 if (user_mode(regs)) { 5517 regs_user->abi = perf_reg_abi(current); 5518 regs_user->regs = regs; 5519 } else if (current->mm) { 5520 perf_get_regs_user(regs_user, regs, regs_user_copy); 5521 } else { 5522 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE; 5523 regs_user->regs = NULL; 5524 } 5525 } 5526 5527 static void perf_sample_regs_intr(struct perf_regs *regs_intr, 5528 struct pt_regs *regs) 5529 { 5530 regs_intr->regs = regs; 5531 regs_intr->abi = perf_reg_abi(current); 5532 } 5533 5534 5535 /* 5536 * Get remaining task size from user stack pointer. 5537 * 5538 * It'd be better to take stack vma map and limit this more 5539 * precisly, but there's no way to get it safely under interrupt, 5540 * so using TASK_SIZE as limit. 5541 */ 5542 static u64 perf_ustack_task_size(struct pt_regs *regs) 5543 { 5544 unsigned long addr = perf_user_stack_pointer(regs); 5545 5546 if (!addr || addr >= TASK_SIZE) 5547 return 0; 5548 5549 return TASK_SIZE - addr; 5550 } 5551 5552 static u16 5553 perf_sample_ustack_size(u16 stack_size, u16 header_size, 5554 struct pt_regs *regs) 5555 { 5556 u64 task_size; 5557 5558 /* No regs, no stack pointer, no dump. */ 5559 if (!regs) 5560 return 0; 5561 5562 /* 5563 * Check if we fit in with the requested stack size into the: 5564 * - TASK_SIZE 5565 * If we don't, we limit the size to the TASK_SIZE. 5566 * 5567 * - remaining sample size 5568 * If we don't, we customize the stack size to 5569 * fit in to the remaining sample size. 5570 */ 5571 5572 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs)); 5573 stack_size = min(stack_size, (u16) task_size); 5574 5575 /* Current header size plus static size and dynamic size. */ 5576 header_size += 2 * sizeof(u64); 5577 5578 /* Do we fit in with the current stack dump size? */ 5579 if ((u16) (header_size + stack_size) < header_size) { 5580 /* 5581 * If we overflow the maximum size for the sample, 5582 * we customize the stack dump size to fit in. 5583 */ 5584 stack_size = USHRT_MAX - header_size - sizeof(u64); 5585 stack_size = round_up(stack_size, sizeof(u64)); 5586 } 5587 5588 return stack_size; 5589 } 5590 5591 static void 5592 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size, 5593 struct pt_regs *regs) 5594 { 5595 /* Case of a kernel thread, nothing to dump */ 5596 if (!regs) { 5597 u64 size = 0; 5598 perf_output_put(handle, size); 5599 } else { 5600 unsigned long sp; 5601 unsigned int rem; 5602 u64 dyn_size; 5603 5604 /* 5605 * We dump: 5606 * static size 5607 * - the size requested by user or the best one we can fit 5608 * in to the sample max size 5609 * data 5610 * - user stack dump data 5611 * dynamic size 5612 * - the actual dumped size 5613 */ 5614 5615 /* Static size. */ 5616 perf_output_put(handle, dump_size); 5617 5618 /* Data. */ 5619 sp = perf_user_stack_pointer(regs); 5620 rem = __output_copy_user(handle, (void *) sp, dump_size); 5621 dyn_size = dump_size - rem; 5622 5623 perf_output_skip(handle, rem); 5624 5625 /* Dynamic size. */ 5626 perf_output_put(handle, dyn_size); 5627 } 5628 } 5629 5630 static void __perf_event_header__init_id(struct perf_event_header *header, 5631 struct perf_sample_data *data, 5632 struct perf_event *event) 5633 { 5634 u64 sample_type = event->attr.sample_type; 5635 5636 data->type = sample_type; 5637 header->size += event->id_header_size; 5638 5639 if (sample_type & PERF_SAMPLE_TID) { 5640 /* namespace issues */ 5641 data->tid_entry.pid = perf_event_pid(event, current); 5642 data->tid_entry.tid = perf_event_tid(event, current); 5643 } 5644 5645 if (sample_type & PERF_SAMPLE_TIME) 5646 data->time = perf_event_clock(event); 5647 5648 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER)) 5649 data->id = primary_event_id(event); 5650 5651 if (sample_type & PERF_SAMPLE_STREAM_ID) 5652 data->stream_id = event->id; 5653 5654 if (sample_type & PERF_SAMPLE_CPU) { 5655 data->cpu_entry.cpu = raw_smp_processor_id(); 5656 data->cpu_entry.reserved = 0; 5657 } 5658 } 5659 5660 void perf_event_header__init_id(struct perf_event_header *header, 5661 struct perf_sample_data *data, 5662 struct perf_event *event) 5663 { 5664 if (event->attr.sample_id_all) 5665 __perf_event_header__init_id(header, data, event); 5666 } 5667 5668 static void __perf_event__output_id_sample(struct perf_output_handle *handle, 5669 struct perf_sample_data *data) 5670 { 5671 u64 sample_type = data->type; 5672 5673 if (sample_type & PERF_SAMPLE_TID) 5674 perf_output_put(handle, data->tid_entry); 5675 5676 if (sample_type & PERF_SAMPLE_TIME) 5677 perf_output_put(handle, data->time); 5678 5679 if (sample_type & PERF_SAMPLE_ID) 5680 perf_output_put(handle, data->id); 5681 5682 if (sample_type & PERF_SAMPLE_STREAM_ID) 5683 perf_output_put(handle, data->stream_id); 5684 5685 if (sample_type & PERF_SAMPLE_CPU) 5686 perf_output_put(handle, data->cpu_entry); 5687 5688 if (sample_type & PERF_SAMPLE_IDENTIFIER) 5689 perf_output_put(handle, data->id); 5690 } 5691 5692 void perf_event__output_id_sample(struct perf_event *event, 5693 struct perf_output_handle *handle, 5694 struct perf_sample_data *sample) 5695 { 5696 if (event->attr.sample_id_all) 5697 __perf_event__output_id_sample(handle, sample); 5698 } 5699 5700 static void perf_output_read_one(struct perf_output_handle *handle, 5701 struct perf_event *event, 5702 u64 enabled, u64 running) 5703 { 5704 u64 read_format = event->attr.read_format; 5705 u64 values[4]; 5706 int n = 0; 5707 5708 values[n++] = perf_event_count(event); 5709 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { 5710 values[n++] = enabled + 5711 atomic64_read(&event->child_total_time_enabled); 5712 } 5713 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { 5714 values[n++] = running + 5715 atomic64_read(&event->child_total_time_running); 5716 } 5717 if (read_format & PERF_FORMAT_ID) 5718 values[n++] = primary_event_id(event); 5719 5720 __output_copy(handle, values, n * sizeof(u64)); 5721 } 5722 5723 /* 5724 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult. 5725 */ 5726 static void perf_output_read_group(struct perf_output_handle *handle, 5727 struct perf_event *event, 5728 u64 enabled, u64 running) 5729 { 5730 struct perf_event *leader = event->group_leader, *sub; 5731 u64 read_format = event->attr.read_format; 5732 u64 values[5]; 5733 int n = 0; 5734 5735 values[n++] = 1 + leader->nr_siblings; 5736 5737 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 5738 values[n++] = enabled; 5739 5740 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 5741 values[n++] = running; 5742 5743 if (leader != event) 5744 leader->pmu->read(leader); 5745 5746 values[n++] = perf_event_count(leader); 5747 if (read_format & PERF_FORMAT_ID) 5748 values[n++] = primary_event_id(leader); 5749 5750 __output_copy(handle, values, n * sizeof(u64)); 5751 5752 list_for_each_entry(sub, &leader->sibling_list, group_entry) { 5753 n = 0; 5754 5755 if ((sub != event) && 5756 (sub->state == PERF_EVENT_STATE_ACTIVE)) 5757 sub->pmu->read(sub); 5758 5759 values[n++] = perf_event_count(sub); 5760 if (read_format & PERF_FORMAT_ID) 5761 values[n++] = primary_event_id(sub); 5762 5763 __output_copy(handle, values, n * sizeof(u64)); 5764 } 5765 } 5766 5767 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\ 5768 PERF_FORMAT_TOTAL_TIME_RUNNING) 5769 5770 static void perf_output_read(struct perf_output_handle *handle, 5771 struct perf_event *event) 5772 { 5773 u64 enabled = 0, running = 0, now; 5774 u64 read_format = event->attr.read_format; 5775 5776 /* 5777 * compute total_time_enabled, total_time_running 5778 * based on snapshot values taken when the event 5779 * was last scheduled in. 5780 * 5781 * we cannot simply called update_context_time() 5782 * because of locking issue as we are called in 5783 * NMI context 5784 */ 5785 if (read_format & PERF_FORMAT_TOTAL_TIMES) 5786 calc_timer_values(event, &now, &enabled, &running); 5787 5788 if (event->attr.read_format & PERF_FORMAT_GROUP) 5789 perf_output_read_group(handle, event, enabled, running); 5790 else 5791 perf_output_read_one(handle, event, enabled, running); 5792 } 5793 5794 void perf_output_sample(struct perf_output_handle *handle, 5795 struct perf_event_header *header, 5796 struct perf_sample_data *data, 5797 struct perf_event *event) 5798 { 5799 u64 sample_type = data->type; 5800 5801 perf_output_put(handle, *header); 5802 5803 if (sample_type & PERF_SAMPLE_IDENTIFIER) 5804 perf_output_put(handle, data->id); 5805 5806 if (sample_type & PERF_SAMPLE_IP) 5807 perf_output_put(handle, data->ip); 5808 5809 if (sample_type & PERF_SAMPLE_TID) 5810 perf_output_put(handle, data->tid_entry); 5811 5812 if (sample_type & PERF_SAMPLE_TIME) 5813 perf_output_put(handle, data->time); 5814 5815 if (sample_type & PERF_SAMPLE_ADDR) 5816 perf_output_put(handle, data->addr); 5817 5818 if (sample_type & PERF_SAMPLE_ID) 5819 perf_output_put(handle, data->id); 5820 5821 if (sample_type & PERF_SAMPLE_STREAM_ID) 5822 perf_output_put(handle, data->stream_id); 5823 5824 if (sample_type & PERF_SAMPLE_CPU) 5825 perf_output_put(handle, data->cpu_entry); 5826 5827 if (sample_type & PERF_SAMPLE_PERIOD) 5828 perf_output_put(handle, data->period); 5829 5830 if (sample_type & PERF_SAMPLE_READ) 5831 perf_output_read(handle, event); 5832 5833 if (sample_type & PERF_SAMPLE_CALLCHAIN) { 5834 if (data->callchain) { 5835 int size = 1; 5836 5837 if (data->callchain) 5838 size += data->callchain->nr; 5839 5840 size *= sizeof(u64); 5841 5842 __output_copy(handle, data->callchain, size); 5843 } else { 5844 u64 nr = 0; 5845 perf_output_put(handle, nr); 5846 } 5847 } 5848 5849 if (sample_type & PERF_SAMPLE_RAW) { 5850 struct perf_raw_record *raw = data->raw; 5851 5852 if (raw) { 5853 struct perf_raw_frag *frag = &raw->frag; 5854 5855 perf_output_put(handle, raw->size); 5856 do { 5857 if (frag->copy) { 5858 __output_custom(handle, frag->copy, 5859 frag->data, frag->size); 5860 } else { 5861 __output_copy(handle, frag->data, 5862 frag->size); 5863 } 5864 if (perf_raw_frag_last(frag)) 5865 break; 5866 frag = frag->next; 5867 } while (1); 5868 if (frag->pad) 5869 __output_skip(handle, NULL, frag->pad); 5870 } else { 5871 struct { 5872 u32 size; 5873 u32 data; 5874 } raw = { 5875 .size = sizeof(u32), 5876 .data = 0, 5877 }; 5878 perf_output_put(handle, raw); 5879 } 5880 } 5881 5882 if (sample_type & PERF_SAMPLE_BRANCH_STACK) { 5883 if (data->br_stack) { 5884 size_t size; 5885 5886 size = data->br_stack->nr 5887 * sizeof(struct perf_branch_entry); 5888 5889 perf_output_put(handle, data->br_stack->nr); 5890 perf_output_copy(handle, data->br_stack->entries, size); 5891 } else { 5892 /* 5893 * we always store at least the value of nr 5894 */ 5895 u64 nr = 0; 5896 perf_output_put(handle, nr); 5897 } 5898 } 5899 5900 if (sample_type & PERF_SAMPLE_REGS_USER) { 5901 u64 abi = data->regs_user.abi; 5902 5903 /* 5904 * If there are no regs to dump, notice it through 5905 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). 5906 */ 5907 perf_output_put(handle, abi); 5908 5909 if (abi) { 5910 u64 mask = event->attr.sample_regs_user; 5911 perf_output_sample_regs(handle, 5912 data->regs_user.regs, 5913 mask); 5914 } 5915 } 5916 5917 if (sample_type & PERF_SAMPLE_STACK_USER) { 5918 perf_output_sample_ustack(handle, 5919 data->stack_user_size, 5920 data->regs_user.regs); 5921 } 5922 5923 if (sample_type & PERF_SAMPLE_WEIGHT) 5924 perf_output_put(handle, data->weight); 5925 5926 if (sample_type & PERF_SAMPLE_DATA_SRC) 5927 perf_output_put(handle, data->data_src.val); 5928 5929 if (sample_type & PERF_SAMPLE_TRANSACTION) 5930 perf_output_put(handle, data->txn); 5931 5932 if (sample_type & PERF_SAMPLE_REGS_INTR) { 5933 u64 abi = data->regs_intr.abi; 5934 /* 5935 * If there are no regs to dump, notice it through 5936 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). 5937 */ 5938 perf_output_put(handle, abi); 5939 5940 if (abi) { 5941 u64 mask = event->attr.sample_regs_intr; 5942 5943 perf_output_sample_regs(handle, 5944 data->regs_intr.regs, 5945 mask); 5946 } 5947 } 5948 5949 if (!event->attr.watermark) { 5950 int wakeup_events = event->attr.wakeup_events; 5951 5952 if (wakeup_events) { 5953 struct ring_buffer *rb = handle->rb; 5954 int events = local_inc_return(&rb->events); 5955 5956 if (events >= wakeup_events) { 5957 local_sub(wakeup_events, &rb->events); 5958 local_inc(&rb->wakeup); 5959 } 5960 } 5961 } 5962 } 5963 5964 void perf_prepare_sample(struct perf_event_header *header, 5965 struct perf_sample_data *data, 5966 struct perf_event *event, 5967 struct pt_regs *regs) 5968 { 5969 u64 sample_type = event->attr.sample_type; 5970 5971 header->type = PERF_RECORD_SAMPLE; 5972 header->size = sizeof(*header) + event->header_size; 5973 5974 header->misc = 0; 5975 header->misc |= perf_misc_flags(regs); 5976 5977 __perf_event_header__init_id(header, data, event); 5978 5979 if (sample_type & PERF_SAMPLE_IP) 5980 data->ip = perf_instruction_pointer(regs); 5981 5982 if (sample_type & PERF_SAMPLE_CALLCHAIN) { 5983 int size = 1; 5984 5985 data->callchain = perf_callchain(event, regs); 5986 5987 if (data->callchain) 5988 size += data->callchain->nr; 5989 5990 header->size += size * sizeof(u64); 5991 } 5992 5993 if (sample_type & PERF_SAMPLE_RAW) { 5994 struct perf_raw_record *raw = data->raw; 5995 int size; 5996 5997 if (raw) { 5998 struct perf_raw_frag *frag = &raw->frag; 5999 u32 sum = 0; 6000 6001 do { 6002 sum += frag->size; 6003 if (perf_raw_frag_last(frag)) 6004 break; 6005 frag = frag->next; 6006 } while (1); 6007 6008 size = round_up(sum + sizeof(u32), sizeof(u64)); 6009 raw->size = size - sizeof(u32); 6010 frag->pad = raw->size - sum; 6011 } else { 6012 size = sizeof(u64); 6013 } 6014 6015 header->size += size; 6016 } 6017 6018 if (sample_type & PERF_SAMPLE_BRANCH_STACK) { 6019 int size = sizeof(u64); /* nr */ 6020 if (data->br_stack) { 6021 size += data->br_stack->nr 6022 * sizeof(struct perf_branch_entry); 6023 } 6024 header->size += size; 6025 } 6026 6027 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER)) 6028 perf_sample_regs_user(&data->regs_user, regs, 6029 &data->regs_user_copy); 6030 6031 if (sample_type & PERF_SAMPLE_REGS_USER) { 6032 /* regs dump ABI info */ 6033 int size = sizeof(u64); 6034 6035 if (data->regs_user.regs) { 6036 u64 mask = event->attr.sample_regs_user; 6037 size += hweight64(mask) * sizeof(u64); 6038 } 6039 6040 header->size += size; 6041 } 6042 6043 if (sample_type & PERF_SAMPLE_STACK_USER) { 6044 /* 6045 * Either we need PERF_SAMPLE_STACK_USER bit to be allways 6046 * processed as the last one or have additional check added 6047 * in case new sample type is added, because we could eat 6048 * up the rest of the sample size. 6049 */ 6050 u16 stack_size = event->attr.sample_stack_user; 6051 u16 size = sizeof(u64); 6052 6053 stack_size = perf_sample_ustack_size(stack_size, header->size, 6054 data->regs_user.regs); 6055 6056 /* 6057 * If there is something to dump, add space for the dump 6058 * itself and for the field that tells the dynamic size, 6059 * which is how many have been actually dumped. 6060 */ 6061 if (stack_size) 6062 size += sizeof(u64) + stack_size; 6063 6064 data->stack_user_size = stack_size; 6065 header->size += size; 6066 } 6067 6068 if (sample_type & PERF_SAMPLE_REGS_INTR) { 6069 /* regs dump ABI info */ 6070 int size = sizeof(u64); 6071 6072 perf_sample_regs_intr(&data->regs_intr, regs); 6073 6074 if (data->regs_intr.regs) { 6075 u64 mask = event->attr.sample_regs_intr; 6076 6077 size += hweight64(mask) * sizeof(u64); 6078 } 6079 6080 header->size += size; 6081 } 6082 } 6083 6084 static void __always_inline 6085 __perf_event_output(struct perf_event *event, 6086 struct perf_sample_data *data, 6087 struct pt_regs *regs, 6088 int (*output_begin)(struct perf_output_handle *, 6089 struct perf_event *, 6090 unsigned int)) 6091 { 6092 struct perf_output_handle handle; 6093 struct perf_event_header header; 6094 6095 /* protect the callchain buffers */ 6096 rcu_read_lock(); 6097 6098 perf_prepare_sample(&header, data, event, regs); 6099 6100 if (output_begin(&handle, event, header.size)) 6101 goto exit; 6102 6103 perf_output_sample(&handle, &header, data, event); 6104 6105 perf_output_end(&handle); 6106 6107 exit: 6108 rcu_read_unlock(); 6109 } 6110 6111 void 6112 perf_event_output_forward(struct perf_event *event, 6113 struct perf_sample_data *data, 6114 struct pt_regs *regs) 6115 { 6116 __perf_event_output(event, data, regs, perf_output_begin_forward); 6117 } 6118 6119 void 6120 perf_event_output_backward(struct perf_event *event, 6121 struct perf_sample_data *data, 6122 struct pt_regs *regs) 6123 { 6124 __perf_event_output(event, data, regs, perf_output_begin_backward); 6125 } 6126 6127 void 6128 perf_event_output(struct perf_event *event, 6129 struct perf_sample_data *data, 6130 struct pt_regs *regs) 6131 { 6132 __perf_event_output(event, data, regs, perf_output_begin); 6133 } 6134 6135 /* 6136 * read event_id 6137 */ 6138 6139 struct perf_read_event { 6140 struct perf_event_header header; 6141 6142 u32 pid; 6143 u32 tid; 6144 }; 6145 6146 static void 6147 perf_event_read_event(struct perf_event *event, 6148 struct task_struct *task) 6149 { 6150 struct perf_output_handle handle; 6151 struct perf_sample_data sample; 6152 struct perf_read_event read_event = { 6153 .header = { 6154 .type = PERF_RECORD_READ, 6155 .misc = 0, 6156 .size = sizeof(read_event) + event->read_size, 6157 }, 6158 .pid = perf_event_pid(event, task), 6159 .tid = perf_event_tid(event, task), 6160 }; 6161 int ret; 6162 6163 perf_event_header__init_id(&read_event.header, &sample, event); 6164 ret = perf_output_begin(&handle, event, read_event.header.size); 6165 if (ret) 6166 return; 6167 6168 perf_output_put(&handle, read_event); 6169 perf_output_read(&handle, event); 6170 perf_event__output_id_sample(event, &handle, &sample); 6171 6172 perf_output_end(&handle); 6173 } 6174 6175 typedef void (perf_iterate_f)(struct perf_event *event, void *data); 6176 6177 static void 6178 perf_iterate_ctx(struct perf_event_context *ctx, 6179 perf_iterate_f output, 6180 void *data, bool all) 6181 { 6182 struct perf_event *event; 6183 6184 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 6185 if (!all) { 6186 if (event->state < PERF_EVENT_STATE_INACTIVE) 6187 continue; 6188 if (!event_filter_match(event)) 6189 continue; 6190 } 6191 6192 output(event, data); 6193 } 6194 } 6195 6196 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data) 6197 { 6198 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events); 6199 struct perf_event *event; 6200 6201 list_for_each_entry_rcu(event, &pel->list, sb_list) { 6202 /* 6203 * Skip events that are not fully formed yet; ensure that 6204 * if we observe event->ctx, both event and ctx will be 6205 * complete enough. See perf_install_in_context(). 6206 */ 6207 if (!smp_load_acquire(&event->ctx)) 6208 continue; 6209 6210 if (event->state < PERF_EVENT_STATE_INACTIVE) 6211 continue; 6212 if (!event_filter_match(event)) 6213 continue; 6214 output(event, data); 6215 } 6216 } 6217 6218 /* 6219 * Iterate all events that need to receive side-band events. 6220 * 6221 * For new callers; ensure that account_pmu_sb_event() includes 6222 * your event, otherwise it might not get delivered. 6223 */ 6224 static void 6225 perf_iterate_sb(perf_iterate_f output, void *data, 6226 struct perf_event_context *task_ctx) 6227 { 6228 struct perf_event_context *ctx; 6229 int ctxn; 6230 6231 rcu_read_lock(); 6232 preempt_disable(); 6233 6234 /* 6235 * If we have task_ctx != NULL we only notify the task context itself. 6236 * The task_ctx is set only for EXIT events before releasing task 6237 * context. 6238 */ 6239 if (task_ctx) { 6240 perf_iterate_ctx(task_ctx, output, data, false); 6241 goto done; 6242 } 6243 6244 perf_iterate_sb_cpu(output, data); 6245 6246 for_each_task_context_nr(ctxn) { 6247 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); 6248 if (ctx) 6249 perf_iterate_ctx(ctx, output, data, false); 6250 } 6251 done: 6252 preempt_enable(); 6253 rcu_read_unlock(); 6254 } 6255 6256 /* 6257 * Clear all file-based filters at exec, they'll have to be 6258 * re-instated when/if these objects are mmapped again. 6259 */ 6260 static void perf_event_addr_filters_exec(struct perf_event *event, void *data) 6261 { 6262 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 6263 struct perf_addr_filter *filter; 6264 unsigned int restart = 0, count = 0; 6265 unsigned long flags; 6266 6267 if (!has_addr_filter(event)) 6268 return; 6269 6270 raw_spin_lock_irqsave(&ifh->lock, flags); 6271 list_for_each_entry(filter, &ifh->list, entry) { 6272 if (filter->inode) { 6273 event->addr_filters_offs[count] = 0; 6274 restart++; 6275 } 6276 6277 count++; 6278 } 6279 6280 if (restart) 6281 event->addr_filters_gen++; 6282 raw_spin_unlock_irqrestore(&ifh->lock, flags); 6283 6284 if (restart) 6285 perf_event_stop(event, 1); 6286 } 6287 6288 void perf_event_exec(void) 6289 { 6290 struct perf_event_context *ctx; 6291 int ctxn; 6292 6293 rcu_read_lock(); 6294 for_each_task_context_nr(ctxn) { 6295 ctx = current->perf_event_ctxp[ctxn]; 6296 if (!ctx) 6297 continue; 6298 6299 perf_event_enable_on_exec(ctxn); 6300 6301 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL, 6302 true); 6303 } 6304 rcu_read_unlock(); 6305 } 6306 6307 struct remote_output { 6308 struct ring_buffer *rb; 6309 int err; 6310 }; 6311 6312 static void __perf_event_output_stop(struct perf_event *event, void *data) 6313 { 6314 struct perf_event *parent = event->parent; 6315 struct remote_output *ro = data; 6316 struct ring_buffer *rb = ro->rb; 6317 struct stop_event_data sd = { 6318 .event = event, 6319 }; 6320 6321 if (!has_aux(event)) 6322 return; 6323 6324 if (!parent) 6325 parent = event; 6326 6327 /* 6328 * In case of inheritance, it will be the parent that links to the 6329 * ring-buffer, but it will be the child that's actually using it. 6330 * 6331 * We are using event::rb to determine if the event should be stopped, 6332 * however this may race with ring_buffer_attach() (through set_output), 6333 * which will make us skip the event that actually needs to be stopped. 6334 * So ring_buffer_attach() has to stop an aux event before re-assigning 6335 * its rb pointer. 6336 */ 6337 if (rcu_dereference(parent->rb) == rb) 6338 ro->err = __perf_event_stop(&sd); 6339 } 6340 6341 static int __perf_pmu_output_stop(void *info) 6342 { 6343 struct perf_event *event = info; 6344 struct pmu *pmu = event->pmu; 6345 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 6346 struct remote_output ro = { 6347 .rb = event->rb, 6348 }; 6349 6350 rcu_read_lock(); 6351 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false); 6352 if (cpuctx->task_ctx) 6353 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop, 6354 &ro, false); 6355 rcu_read_unlock(); 6356 6357 return ro.err; 6358 } 6359 6360 static void perf_pmu_output_stop(struct perf_event *event) 6361 { 6362 struct perf_event *iter; 6363 int err, cpu; 6364 6365 restart: 6366 rcu_read_lock(); 6367 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) { 6368 /* 6369 * For per-CPU events, we need to make sure that neither they 6370 * nor their children are running; for cpu==-1 events it's 6371 * sufficient to stop the event itself if it's active, since 6372 * it can't have children. 6373 */ 6374 cpu = iter->cpu; 6375 if (cpu == -1) 6376 cpu = READ_ONCE(iter->oncpu); 6377 6378 if (cpu == -1) 6379 continue; 6380 6381 err = cpu_function_call(cpu, __perf_pmu_output_stop, event); 6382 if (err == -EAGAIN) { 6383 rcu_read_unlock(); 6384 goto restart; 6385 } 6386 } 6387 rcu_read_unlock(); 6388 } 6389 6390 /* 6391 * task tracking -- fork/exit 6392 * 6393 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task 6394 */ 6395 6396 struct perf_task_event { 6397 struct task_struct *task; 6398 struct perf_event_context *task_ctx; 6399 6400 struct { 6401 struct perf_event_header header; 6402 6403 u32 pid; 6404 u32 ppid; 6405 u32 tid; 6406 u32 ptid; 6407 u64 time; 6408 } event_id; 6409 }; 6410 6411 static int perf_event_task_match(struct perf_event *event) 6412 { 6413 return event->attr.comm || event->attr.mmap || 6414 event->attr.mmap2 || event->attr.mmap_data || 6415 event->attr.task; 6416 } 6417 6418 static void perf_event_task_output(struct perf_event *event, 6419 void *data) 6420 { 6421 struct perf_task_event *task_event = data; 6422 struct perf_output_handle handle; 6423 struct perf_sample_data sample; 6424 struct task_struct *task = task_event->task; 6425 int ret, size = task_event->event_id.header.size; 6426 6427 if (!perf_event_task_match(event)) 6428 return; 6429 6430 perf_event_header__init_id(&task_event->event_id.header, &sample, event); 6431 6432 ret = perf_output_begin(&handle, event, 6433 task_event->event_id.header.size); 6434 if (ret) 6435 goto out; 6436 6437 task_event->event_id.pid = perf_event_pid(event, task); 6438 task_event->event_id.ppid = perf_event_pid(event, current); 6439 6440 task_event->event_id.tid = perf_event_tid(event, task); 6441 task_event->event_id.ptid = perf_event_tid(event, current); 6442 6443 task_event->event_id.time = perf_event_clock(event); 6444 6445 perf_output_put(&handle, task_event->event_id); 6446 6447 perf_event__output_id_sample(event, &handle, &sample); 6448 6449 perf_output_end(&handle); 6450 out: 6451 task_event->event_id.header.size = size; 6452 } 6453 6454 static void perf_event_task(struct task_struct *task, 6455 struct perf_event_context *task_ctx, 6456 int new) 6457 { 6458 struct perf_task_event task_event; 6459 6460 if (!atomic_read(&nr_comm_events) && 6461 !atomic_read(&nr_mmap_events) && 6462 !atomic_read(&nr_task_events)) 6463 return; 6464 6465 task_event = (struct perf_task_event){ 6466 .task = task, 6467 .task_ctx = task_ctx, 6468 .event_id = { 6469 .header = { 6470 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT, 6471 .misc = 0, 6472 .size = sizeof(task_event.event_id), 6473 }, 6474 /* .pid */ 6475 /* .ppid */ 6476 /* .tid */ 6477 /* .ptid */ 6478 /* .time */ 6479 }, 6480 }; 6481 6482 perf_iterate_sb(perf_event_task_output, 6483 &task_event, 6484 task_ctx); 6485 } 6486 6487 void perf_event_fork(struct task_struct *task) 6488 { 6489 perf_event_task(task, NULL, 1); 6490 } 6491 6492 /* 6493 * comm tracking 6494 */ 6495 6496 struct perf_comm_event { 6497 struct task_struct *task; 6498 char *comm; 6499 int comm_size; 6500 6501 struct { 6502 struct perf_event_header header; 6503 6504 u32 pid; 6505 u32 tid; 6506 } event_id; 6507 }; 6508 6509 static int perf_event_comm_match(struct perf_event *event) 6510 { 6511 return event->attr.comm; 6512 } 6513 6514 static void perf_event_comm_output(struct perf_event *event, 6515 void *data) 6516 { 6517 struct perf_comm_event *comm_event = data; 6518 struct perf_output_handle handle; 6519 struct perf_sample_data sample; 6520 int size = comm_event->event_id.header.size; 6521 int ret; 6522 6523 if (!perf_event_comm_match(event)) 6524 return; 6525 6526 perf_event_header__init_id(&comm_event->event_id.header, &sample, event); 6527 ret = perf_output_begin(&handle, event, 6528 comm_event->event_id.header.size); 6529 6530 if (ret) 6531 goto out; 6532 6533 comm_event->event_id.pid = perf_event_pid(event, comm_event->task); 6534 comm_event->event_id.tid = perf_event_tid(event, comm_event->task); 6535 6536 perf_output_put(&handle, comm_event->event_id); 6537 __output_copy(&handle, comm_event->comm, 6538 comm_event->comm_size); 6539 6540 perf_event__output_id_sample(event, &handle, &sample); 6541 6542 perf_output_end(&handle); 6543 out: 6544 comm_event->event_id.header.size = size; 6545 } 6546 6547 static void perf_event_comm_event(struct perf_comm_event *comm_event) 6548 { 6549 char comm[TASK_COMM_LEN]; 6550 unsigned int size; 6551 6552 memset(comm, 0, sizeof(comm)); 6553 strlcpy(comm, comm_event->task->comm, sizeof(comm)); 6554 size = ALIGN(strlen(comm)+1, sizeof(u64)); 6555 6556 comm_event->comm = comm; 6557 comm_event->comm_size = size; 6558 6559 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size; 6560 6561 perf_iterate_sb(perf_event_comm_output, 6562 comm_event, 6563 NULL); 6564 } 6565 6566 void perf_event_comm(struct task_struct *task, bool exec) 6567 { 6568 struct perf_comm_event comm_event; 6569 6570 if (!atomic_read(&nr_comm_events)) 6571 return; 6572 6573 comm_event = (struct perf_comm_event){ 6574 .task = task, 6575 /* .comm */ 6576 /* .comm_size */ 6577 .event_id = { 6578 .header = { 6579 .type = PERF_RECORD_COMM, 6580 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0, 6581 /* .size */ 6582 }, 6583 /* .pid */ 6584 /* .tid */ 6585 }, 6586 }; 6587 6588 perf_event_comm_event(&comm_event); 6589 } 6590 6591 /* 6592 * mmap tracking 6593 */ 6594 6595 struct perf_mmap_event { 6596 struct vm_area_struct *vma; 6597 6598 const char *file_name; 6599 int file_size; 6600 int maj, min; 6601 u64 ino; 6602 u64 ino_generation; 6603 u32 prot, flags; 6604 6605 struct { 6606 struct perf_event_header header; 6607 6608 u32 pid; 6609 u32 tid; 6610 u64 start; 6611 u64 len; 6612 u64 pgoff; 6613 } event_id; 6614 }; 6615 6616 static int perf_event_mmap_match(struct perf_event *event, 6617 void *data) 6618 { 6619 struct perf_mmap_event *mmap_event = data; 6620 struct vm_area_struct *vma = mmap_event->vma; 6621 int executable = vma->vm_flags & VM_EXEC; 6622 6623 return (!executable && event->attr.mmap_data) || 6624 (executable && (event->attr.mmap || event->attr.mmap2)); 6625 } 6626 6627 static void perf_event_mmap_output(struct perf_event *event, 6628 void *data) 6629 { 6630 struct perf_mmap_event *mmap_event = data; 6631 struct perf_output_handle handle; 6632 struct perf_sample_data sample; 6633 int size = mmap_event->event_id.header.size; 6634 int ret; 6635 6636 if (!perf_event_mmap_match(event, data)) 6637 return; 6638 6639 if (event->attr.mmap2) { 6640 mmap_event->event_id.header.type = PERF_RECORD_MMAP2; 6641 mmap_event->event_id.header.size += sizeof(mmap_event->maj); 6642 mmap_event->event_id.header.size += sizeof(mmap_event->min); 6643 mmap_event->event_id.header.size += sizeof(mmap_event->ino); 6644 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation); 6645 mmap_event->event_id.header.size += sizeof(mmap_event->prot); 6646 mmap_event->event_id.header.size += sizeof(mmap_event->flags); 6647 } 6648 6649 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event); 6650 ret = perf_output_begin(&handle, event, 6651 mmap_event->event_id.header.size); 6652 if (ret) 6653 goto out; 6654 6655 mmap_event->event_id.pid = perf_event_pid(event, current); 6656 mmap_event->event_id.tid = perf_event_tid(event, current); 6657 6658 perf_output_put(&handle, mmap_event->event_id); 6659 6660 if (event->attr.mmap2) { 6661 perf_output_put(&handle, mmap_event->maj); 6662 perf_output_put(&handle, mmap_event->min); 6663 perf_output_put(&handle, mmap_event->ino); 6664 perf_output_put(&handle, mmap_event->ino_generation); 6665 perf_output_put(&handle, mmap_event->prot); 6666 perf_output_put(&handle, mmap_event->flags); 6667 } 6668 6669 __output_copy(&handle, mmap_event->file_name, 6670 mmap_event->file_size); 6671 6672 perf_event__output_id_sample(event, &handle, &sample); 6673 6674 perf_output_end(&handle); 6675 out: 6676 mmap_event->event_id.header.size = size; 6677 } 6678 6679 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) 6680 { 6681 struct vm_area_struct *vma = mmap_event->vma; 6682 struct file *file = vma->vm_file; 6683 int maj = 0, min = 0; 6684 u64 ino = 0, gen = 0; 6685 u32 prot = 0, flags = 0; 6686 unsigned int size; 6687 char tmp[16]; 6688 char *buf = NULL; 6689 char *name; 6690 6691 if (vma->vm_flags & VM_READ) 6692 prot |= PROT_READ; 6693 if (vma->vm_flags & VM_WRITE) 6694 prot |= PROT_WRITE; 6695 if (vma->vm_flags & VM_EXEC) 6696 prot |= PROT_EXEC; 6697 6698 if (vma->vm_flags & VM_MAYSHARE) 6699 flags = MAP_SHARED; 6700 else 6701 flags = MAP_PRIVATE; 6702 6703 if (vma->vm_flags & VM_DENYWRITE) 6704 flags |= MAP_DENYWRITE; 6705 if (vma->vm_flags & VM_MAYEXEC) 6706 flags |= MAP_EXECUTABLE; 6707 if (vma->vm_flags & VM_LOCKED) 6708 flags |= MAP_LOCKED; 6709 if (vma->vm_flags & VM_HUGETLB) 6710 flags |= MAP_HUGETLB; 6711 6712 if (file) { 6713 struct inode *inode; 6714 dev_t dev; 6715 6716 buf = kmalloc(PATH_MAX, GFP_KERNEL); 6717 if (!buf) { 6718 name = "//enomem"; 6719 goto cpy_name; 6720 } 6721 /* 6722 * d_path() works from the end of the rb backwards, so we 6723 * need to add enough zero bytes after the string to handle 6724 * the 64bit alignment we do later. 6725 */ 6726 name = file_path(file, buf, PATH_MAX - sizeof(u64)); 6727 if (IS_ERR(name)) { 6728 name = "//toolong"; 6729 goto cpy_name; 6730 } 6731 inode = file_inode(vma->vm_file); 6732 dev = inode->i_sb->s_dev; 6733 ino = inode->i_ino; 6734 gen = inode->i_generation; 6735 maj = MAJOR(dev); 6736 min = MINOR(dev); 6737 6738 goto got_name; 6739 } else { 6740 if (vma->vm_ops && vma->vm_ops->name) { 6741 name = (char *) vma->vm_ops->name(vma); 6742 if (name) 6743 goto cpy_name; 6744 } 6745 6746 name = (char *)arch_vma_name(vma); 6747 if (name) 6748 goto cpy_name; 6749 6750 if (vma->vm_start <= vma->vm_mm->start_brk && 6751 vma->vm_end >= vma->vm_mm->brk) { 6752 name = "[heap]"; 6753 goto cpy_name; 6754 } 6755 if (vma->vm_start <= vma->vm_mm->start_stack && 6756 vma->vm_end >= vma->vm_mm->start_stack) { 6757 name = "[stack]"; 6758 goto cpy_name; 6759 } 6760 6761 name = "//anon"; 6762 goto cpy_name; 6763 } 6764 6765 cpy_name: 6766 strlcpy(tmp, name, sizeof(tmp)); 6767 name = tmp; 6768 got_name: 6769 /* 6770 * Since our buffer works in 8 byte units we need to align our string 6771 * size to a multiple of 8. However, we must guarantee the tail end is 6772 * zero'd out to avoid leaking random bits to userspace. 6773 */ 6774 size = strlen(name)+1; 6775 while (!IS_ALIGNED(size, sizeof(u64))) 6776 name[size++] = '\0'; 6777 6778 mmap_event->file_name = name; 6779 mmap_event->file_size = size; 6780 mmap_event->maj = maj; 6781 mmap_event->min = min; 6782 mmap_event->ino = ino; 6783 mmap_event->ino_generation = gen; 6784 mmap_event->prot = prot; 6785 mmap_event->flags = flags; 6786 6787 if (!(vma->vm_flags & VM_EXEC)) 6788 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA; 6789 6790 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size; 6791 6792 perf_iterate_sb(perf_event_mmap_output, 6793 mmap_event, 6794 NULL); 6795 6796 kfree(buf); 6797 } 6798 6799 /* 6800 * Check whether inode and address range match filter criteria. 6801 */ 6802 static bool perf_addr_filter_match(struct perf_addr_filter *filter, 6803 struct file *file, unsigned long offset, 6804 unsigned long size) 6805 { 6806 if (filter->inode != file_inode(file)) 6807 return false; 6808 6809 if (filter->offset > offset + size) 6810 return false; 6811 6812 if (filter->offset + filter->size < offset) 6813 return false; 6814 6815 return true; 6816 } 6817 6818 static void __perf_addr_filters_adjust(struct perf_event *event, void *data) 6819 { 6820 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 6821 struct vm_area_struct *vma = data; 6822 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags; 6823 struct file *file = vma->vm_file; 6824 struct perf_addr_filter *filter; 6825 unsigned int restart = 0, count = 0; 6826 6827 if (!has_addr_filter(event)) 6828 return; 6829 6830 if (!file) 6831 return; 6832 6833 raw_spin_lock_irqsave(&ifh->lock, flags); 6834 list_for_each_entry(filter, &ifh->list, entry) { 6835 if (perf_addr_filter_match(filter, file, off, 6836 vma->vm_end - vma->vm_start)) { 6837 event->addr_filters_offs[count] = vma->vm_start; 6838 restart++; 6839 } 6840 6841 count++; 6842 } 6843 6844 if (restart) 6845 event->addr_filters_gen++; 6846 raw_spin_unlock_irqrestore(&ifh->lock, flags); 6847 6848 if (restart) 6849 perf_event_stop(event, 1); 6850 } 6851 6852 /* 6853 * Adjust all task's events' filters to the new vma 6854 */ 6855 static void perf_addr_filters_adjust(struct vm_area_struct *vma) 6856 { 6857 struct perf_event_context *ctx; 6858 int ctxn; 6859 6860 /* 6861 * Data tracing isn't supported yet and as such there is no need 6862 * to keep track of anything that isn't related to executable code: 6863 */ 6864 if (!(vma->vm_flags & VM_EXEC)) 6865 return; 6866 6867 rcu_read_lock(); 6868 for_each_task_context_nr(ctxn) { 6869 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); 6870 if (!ctx) 6871 continue; 6872 6873 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true); 6874 } 6875 rcu_read_unlock(); 6876 } 6877 6878 void perf_event_mmap(struct vm_area_struct *vma) 6879 { 6880 struct perf_mmap_event mmap_event; 6881 6882 if (!atomic_read(&nr_mmap_events)) 6883 return; 6884 6885 mmap_event = (struct perf_mmap_event){ 6886 .vma = vma, 6887 /* .file_name */ 6888 /* .file_size */ 6889 .event_id = { 6890 .header = { 6891 .type = PERF_RECORD_MMAP, 6892 .misc = PERF_RECORD_MISC_USER, 6893 /* .size */ 6894 }, 6895 /* .pid */ 6896 /* .tid */ 6897 .start = vma->vm_start, 6898 .len = vma->vm_end - vma->vm_start, 6899 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT, 6900 }, 6901 /* .maj (attr_mmap2 only) */ 6902 /* .min (attr_mmap2 only) */ 6903 /* .ino (attr_mmap2 only) */ 6904 /* .ino_generation (attr_mmap2 only) */ 6905 /* .prot (attr_mmap2 only) */ 6906 /* .flags (attr_mmap2 only) */ 6907 }; 6908 6909 perf_addr_filters_adjust(vma); 6910 perf_event_mmap_event(&mmap_event); 6911 } 6912 6913 void perf_event_aux_event(struct perf_event *event, unsigned long head, 6914 unsigned long size, u64 flags) 6915 { 6916 struct perf_output_handle handle; 6917 struct perf_sample_data sample; 6918 struct perf_aux_event { 6919 struct perf_event_header header; 6920 u64 offset; 6921 u64 size; 6922 u64 flags; 6923 } rec = { 6924 .header = { 6925 .type = PERF_RECORD_AUX, 6926 .misc = 0, 6927 .size = sizeof(rec), 6928 }, 6929 .offset = head, 6930 .size = size, 6931 .flags = flags, 6932 }; 6933 int ret; 6934 6935 perf_event_header__init_id(&rec.header, &sample, event); 6936 ret = perf_output_begin(&handle, event, rec.header.size); 6937 6938 if (ret) 6939 return; 6940 6941 perf_output_put(&handle, rec); 6942 perf_event__output_id_sample(event, &handle, &sample); 6943 6944 perf_output_end(&handle); 6945 } 6946 6947 /* 6948 * Lost/dropped samples logging 6949 */ 6950 void perf_log_lost_samples(struct perf_event *event, u64 lost) 6951 { 6952 struct perf_output_handle handle; 6953 struct perf_sample_data sample; 6954 int ret; 6955 6956 struct { 6957 struct perf_event_header header; 6958 u64 lost; 6959 } lost_samples_event = { 6960 .header = { 6961 .type = PERF_RECORD_LOST_SAMPLES, 6962 .misc = 0, 6963 .size = sizeof(lost_samples_event), 6964 }, 6965 .lost = lost, 6966 }; 6967 6968 perf_event_header__init_id(&lost_samples_event.header, &sample, event); 6969 6970 ret = perf_output_begin(&handle, event, 6971 lost_samples_event.header.size); 6972 if (ret) 6973 return; 6974 6975 perf_output_put(&handle, lost_samples_event); 6976 perf_event__output_id_sample(event, &handle, &sample); 6977 perf_output_end(&handle); 6978 } 6979 6980 /* 6981 * context_switch tracking 6982 */ 6983 6984 struct perf_switch_event { 6985 struct task_struct *task; 6986 struct task_struct *next_prev; 6987 6988 struct { 6989 struct perf_event_header header; 6990 u32 next_prev_pid; 6991 u32 next_prev_tid; 6992 } event_id; 6993 }; 6994 6995 static int perf_event_switch_match(struct perf_event *event) 6996 { 6997 return event->attr.context_switch; 6998 } 6999 7000 static void perf_event_switch_output(struct perf_event *event, void *data) 7001 { 7002 struct perf_switch_event *se = data; 7003 struct perf_output_handle handle; 7004 struct perf_sample_data sample; 7005 int ret; 7006 7007 if (!perf_event_switch_match(event)) 7008 return; 7009 7010 /* Only CPU-wide events are allowed to see next/prev pid/tid */ 7011 if (event->ctx->task) { 7012 se->event_id.header.type = PERF_RECORD_SWITCH; 7013 se->event_id.header.size = sizeof(se->event_id.header); 7014 } else { 7015 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE; 7016 se->event_id.header.size = sizeof(se->event_id); 7017 se->event_id.next_prev_pid = 7018 perf_event_pid(event, se->next_prev); 7019 se->event_id.next_prev_tid = 7020 perf_event_tid(event, se->next_prev); 7021 } 7022 7023 perf_event_header__init_id(&se->event_id.header, &sample, event); 7024 7025 ret = perf_output_begin(&handle, event, se->event_id.header.size); 7026 if (ret) 7027 return; 7028 7029 if (event->ctx->task) 7030 perf_output_put(&handle, se->event_id.header); 7031 else 7032 perf_output_put(&handle, se->event_id); 7033 7034 perf_event__output_id_sample(event, &handle, &sample); 7035 7036 perf_output_end(&handle); 7037 } 7038 7039 static void perf_event_switch(struct task_struct *task, 7040 struct task_struct *next_prev, bool sched_in) 7041 { 7042 struct perf_switch_event switch_event; 7043 7044 /* N.B. caller checks nr_switch_events != 0 */ 7045 7046 switch_event = (struct perf_switch_event){ 7047 .task = task, 7048 .next_prev = next_prev, 7049 .event_id = { 7050 .header = { 7051 /* .type */ 7052 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT, 7053 /* .size */ 7054 }, 7055 /* .next_prev_pid */ 7056 /* .next_prev_tid */ 7057 }, 7058 }; 7059 7060 perf_iterate_sb(perf_event_switch_output, 7061 &switch_event, 7062 NULL); 7063 } 7064 7065 /* 7066 * IRQ throttle logging 7067 */ 7068 7069 static void perf_log_throttle(struct perf_event *event, int enable) 7070 { 7071 struct perf_output_handle handle; 7072 struct perf_sample_data sample; 7073 int ret; 7074 7075 struct { 7076 struct perf_event_header header; 7077 u64 time; 7078 u64 id; 7079 u64 stream_id; 7080 } throttle_event = { 7081 .header = { 7082 .type = PERF_RECORD_THROTTLE, 7083 .misc = 0, 7084 .size = sizeof(throttle_event), 7085 }, 7086 .time = perf_event_clock(event), 7087 .id = primary_event_id(event), 7088 .stream_id = event->id, 7089 }; 7090 7091 if (enable) 7092 throttle_event.header.type = PERF_RECORD_UNTHROTTLE; 7093 7094 perf_event_header__init_id(&throttle_event.header, &sample, event); 7095 7096 ret = perf_output_begin(&handle, event, 7097 throttle_event.header.size); 7098 if (ret) 7099 return; 7100 7101 perf_output_put(&handle, throttle_event); 7102 perf_event__output_id_sample(event, &handle, &sample); 7103 perf_output_end(&handle); 7104 } 7105 7106 static void perf_log_itrace_start(struct perf_event *event) 7107 { 7108 struct perf_output_handle handle; 7109 struct perf_sample_data sample; 7110 struct perf_aux_event { 7111 struct perf_event_header header; 7112 u32 pid; 7113 u32 tid; 7114 } rec; 7115 int ret; 7116 7117 if (event->parent) 7118 event = event->parent; 7119 7120 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) || 7121 event->hw.itrace_started) 7122 return; 7123 7124 rec.header.type = PERF_RECORD_ITRACE_START; 7125 rec.header.misc = 0; 7126 rec.header.size = sizeof(rec); 7127 rec.pid = perf_event_pid(event, current); 7128 rec.tid = perf_event_tid(event, current); 7129 7130 perf_event_header__init_id(&rec.header, &sample, event); 7131 ret = perf_output_begin(&handle, event, rec.header.size); 7132 7133 if (ret) 7134 return; 7135 7136 perf_output_put(&handle, rec); 7137 perf_event__output_id_sample(event, &handle, &sample); 7138 7139 perf_output_end(&handle); 7140 } 7141 7142 static int 7143 __perf_event_account_interrupt(struct perf_event *event, int throttle) 7144 { 7145 struct hw_perf_event *hwc = &event->hw; 7146 int ret = 0; 7147 u64 seq; 7148 7149 seq = __this_cpu_read(perf_throttled_seq); 7150 if (seq != hwc->interrupts_seq) { 7151 hwc->interrupts_seq = seq; 7152 hwc->interrupts = 1; 7153 } else { 7154 hwc->interrupts++; 7155 if (unlikely(throttle 7156 && hwc->interrupts >= max_samples_per_tick)) { 7157 __this_cpu_inc(perf_throttled_count); 7158 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); 7159 hwc->interrupts = MAX_INTERRUPTS; 7160 perf_log_throttle(event, 0); 7161 ret = 1; 7162 } 7163 } 7164 7165 if (event->attr.freq) { 7166 u64 now = perf_clock(); 7167 s64 delta = now - hwc->freq_time_stamp; 7168 7169 hwc->freq_time_stamp = now; 7170 7171 if (delta > 0 && delta < 2*TICK_NSEC) 7172 perf_adjust_period(event, delta, hwc->last_period, true); 7173 } 7174 7175 return ret; 7176 } 7177 7178 int perf_event_account_interrupt(struct perf_event *event) 7179 { 7180 return __perf_event_account_interrupt(event, 1); 7181 } 7182 7183 /* 7184 * Generic event overflow handling, sampling. 7185 */ 7186 7187 static int __perf_event_overflow(struct perf_event *event, 7188 int throttle, struct perf_sample_data *data, 7189 struct pt_regs *regs) 7190 { 7191 int events = atomic_read(&event->event_limit); 7192 int ret = 0; 7193 7194 /* 7195 * Non-sampling counters might still use the PMI to fold short 7196 * hardware counters, ignore those. 7197 */ 7198 if (unlikely(!is_sampling_event(event))) 7199 return 0; 7200 7201 ret = __perf_event_account_interrupt(event, throttle); 7202 7203 /* 7204 * XXX event_limit might not quite work as expected on inherited 7205 * events 7206 */ 7207 7208 event->pending_kill = POLL_IN; 7209 if (events && atomic_dec_and_test(&event->event_limit)) { 7210 ret = 1; 7211 event->pending_kill = POLL_HUP; 7212 7213 perf_event_disable_inatomic(event); 7214 } 7215 7216 READ_ONCE(event->overflow_handler)(event, data, regs); 7217 7218 if (*perf_event_fasync(event) && event->pending_kill) { 7219 event->pending_wakeup = 1; 7220 irq_work_queue(&event->pending); 7221 } 7222 7223 return ret; 7224 } 7225 7226 int perf_event_overflow(struct perf_event *event, 7227 struct perf_sample_data *data, 7228 struct pt_regs *regs) 7229 { 7230 return __perf_event_overflow(event, 1, data, regs); 7231 } 7232 7233 /* 7234 * Generic software event infrastructure 7235 */ 7236 7237 struct swevent_htable { 7238 struct swevent_hlist *swevent_hlist; 7239 struct mutex hlist_mutex; 7240 int hlist_refcount; 7241 7242 /* Recursion avoidance in each contexts */ 7243 int recursion[PERF_NR_CONTEXTS]; 7244 }; 7245 7246 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable); 7247 7248 /* 7249 * We directly increment event->count and keep a second value in 7250 * event->hw.period_left to count intervals. This period event 7251 * is kept in the range [-sample_period, 0] so that we can use the 7252 * sign as trigger. 7253 */ 7254 7255 u64 perf_swevent_set_period(struct perf_event *event) 7256 { 7257 struct hw_perf_event *hwc = &event->hw; 7258 u64 period = hwc->last_period; 7259 u64 nr, offset; 7260 s64 old, val; 7261 7262 hwc->last_period = hwc->sample_period; 7263 7264 again: 7265 old = val = local64_read(&hwc->period_left); 7266 if (val < 0) 7267 return 0; 7268 7269 nr = div64_u64(period + val, period); 7270 offset = nr * period; 7271 val -= offset; 7272 if (local64_cmpxchg(&hwc->period_left, old, val) != old) 7273 goto again; 7274 7275 return nr; 7276 } 7277 7278 static void perf_swevent_overflow(struct perf_event *event, u64 overflow, 7279 struct perf_sample_data *data, 7280 struct pt_regs *regs) 7281 { 7282 struct hw_perf_event *hwc = &event->hw; 7283 int throttle = 0; 7284 7285 if (!overflow) 7286 overflow = perf_swevent_set_period(event); 7287 7288 if (hwc->interrupts == MAX_INTERRUPTS) 7289 return; 7290 7291 for (; overflow; overflow--) { 7292 if (__perf_event_overflow(event, throttle, 7293 data, regs)) { 7294 /* 7295 * We inhibit the overflow from happening when 7296 * hwc->interrupts == MAX_INTERRUPTS. 7297 */ 7298 break; 7299 } 7300 throttle = 1; 7301 } 7302 } 7303 7304 static void perf_swevent_event(struct perf_event *event, u64 nr, 7305 struct perf_sample_data *data, 7306 struct pt_regs *regs) 7307 { 7308 struct hw_perf_event *hwc = &event->hw; 7309 7310 local64_add(nr, &event->count); 7311 7312 if (!regs) 7313 return; 7314 7315 if (!is_sampling_event(event)) 7316 return; 7317 7318 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) { 7319 data->period = nr; 7320 return perf_swevent_overflow(event, 1, data, regs); 7321 } else 7322 data->period = event->hw.last_period; 7323 7324 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq) 7325 return perf_swevent_overflow(event, 1, data, regs); 7326 7327 if (local64_add_negative(nr, &hwc->period_left)) 7328 return; 7329 7330 perf_swevent_overflow(event, 0, data, regs); 7331 } 7332 7333 static int perf_exclude_event(struct perf_event *event, 7334 struct pt_regs *regs) 7335 { 7336 if (event->hw.state & PERF_HES_STOPPED) 7337 return 1; 7338 7339 if (regs) { 7340 if (event->attr.exclude_user && user_mode(regs)) 7341 return 1; 7342 7343 if (event->attr.exclude_kernel && !user_mode(regs)) 7344 return 1; 7345 } 7346 7347 return 0; 7348 } 7349 7350 static int perf_swevent_match(struct perf_event *event, 7351 enum perf_type_id type, 7352 u32 event_id, 7353 struct perf_sample_data *data, 7354 struct pt_regs *regs) 7355 { 7356 if (event->attr.type != type) 7357 return 0; 7358 7359 if (event->attr.config != event_id) 7360 return 0; 7361 7362 if (perf_exclude_event(event, regs)) 7363 return 0; 7364 7365 return 1; 7366 } 7367 7368 static inline u64 swevent_hash(u64 type, u32 event_id) 7369 { 7370 u64 val = event_id | (type << 32); 7371 7372 return hash_64(val, SWEVENT_HLIST_BITS); 7373 } 7374 7375 static inline struct hlist_head * 7376 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id) 7377 { 7378 u64 hash = swevent_hash(type, event_id); 7379 7380 return &hlist->heads[hash]; 7381 } 7382 7383 /* For the read side: events when they trigger */ 7384 static inline struct hlist_head * 7385 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id) 7386 { 7387 struct swevent_hlist *hlist; 7388 7389 hlist = rcu_dereference(swhash->swevent_hlist); 7390 if (!hlist) 7391 return NULL; 7392 7393 return __find_swevent_head(hlist, type, event_id); 7394 } 7395 7396 /* For the event head insertion and removal in the hlist */ 7397 static inline struct hlist_head * 7398 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event) 7399 { 7400 struct swevent_hlist *hlist; 7401 u32 event_id = event->attr.config; 7402 u64 type = event->attr.type; 7403 7404 /* 7405 * Event scheduling is always serialized against hlist allocation 7406 * and release. Which makes the protected version suitable here. 7407 * The context lock guarantees that. 7408 */ 7409 hlist = rcu_dereference_protected(swhash->swevent_hlist, 7410 lockdep_is_held(&event->ctx->lock)); 7411 if (!hlist) 7412 return NULL; 7413 7414 return __find_swevent_head(hlist, type, event_id); 7415 } 7416 7417 static void do_perf_sw_event(enum perf_type_id type, u32 event_id, 7418 u64 nr, 7419 struct perf_sample_data *data, 7420 struct pt_regs *regs) 7421 { 7422 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 7423 struct perf_event *event; 7424 struct hlist_head *head; 7425 7426 rcu_read_lock(); 7427 head = find_swevent_head_rcu(swhash, type, event_id); 7428 if (!head) 7429 goto end; 7430 7431 hlist_for_each_entry_rcu(event, head, hlist_entry) { 7432 if (perf_swevent_match(event, type, event_id, data, regs)) 7433 perf_swevent_event(event, nr, data, regs); 7434 } 7435 end: 7436 rcu_read_unlock(); 7437 } 7438 7439 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]); 7440 7441 int perf_swevent_get_recursion_context(void) 7442 { 7443 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 7444 7445 return get_recursion_context(swhash->recursion); 7446 } 7447 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context); 7448 7449 void perf_swevent_put_recursion_context(int rctx) 7450 { 7451 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 7452 7453 put_recursion_context(swhash->recursion, rctx); 7454 } 7455 7456 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) 7457 { 7458 struct perf_sample_data data; 7459 7460 if (WARN_ON_ONCE(!regs)) 7461 return; 7462 7463 perf_sample_data_init(&data, addr, 0); 7464 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs); 7465 } 7466 7467 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) 7468 { 7469 int rctx; 7470 7471 preempt_disable_notrace(); 7472 rctx = perf_swevent_get_recursion_context(); 7473 if (unlikely(rctx < 0)) 7474 goto fail; 7475 7476 ___perf_sw_event(event_id, nr, regs, addr); 7477 7478 perf_swevent_put_recursion_context(rctx); 7479 fail: 7480 preempt_enable_notrace(); 7481 } 7482 7483 static void perf_swevent_read(struct perf_event *event) 7484 { 7485 } 7486 7487 static int perf_swevent_add(struct perf_event *event, int flags) 7488 { 7489 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 7490 struct hw_perf_event *hwc = &event->hw; 7491 struct hlist_head *head; 7492 7493 if (is_sampling_event(event)) { 7494 hwc->last_period = hwc->sample_period; 7495 perf_swevent_set_period(event); 7496 } 7497 7498 hwc->state = !(flags & PERF_EF_START); 7499 7500 head = find_swevent_head(swhash, event); 7501 if (WARN_ON_ONCE(!head)) 7502 return -EINVAL; 7503 7504 hlist_add_head_rcu(&event->hlist_entry, head); 7505 perf_event_update_userpage(event); 7506 7507 return 0; 7508 } 7509 7510 static void perf_swevent_del(struct perf_event *event, int flags) 7511 { 7512 hlist_del_rcu(&event->hlist_entry); 7513 } 7514 7515 static void perf_swevent_start(struct perf_event *event, int flags) 7516 { 7517 event->hw.state = 0; 7518 } 7519 7520 static void perf_swevent_stop(struct perf_event *event, int flags) 7521 { 7522 event->hw.state = PERF_HES_STOPPED; 7523 } 7524 7525 /* Deref the hlist from the update side */ 7526 static inline struct swevent_hlist * 7527 swevent_hlist_deref(struct swevent_htable *swhash) 7528 { 7529 return rcu_dereference_protected(swhash->swevent_hlist, 7530 lockdep_is_held(&swhash->hlist_mutex)); 7531 } 7532 7533 static void swevent_hlist_release(struct swevent_htable *swhash) 7534 { 7535 struct swevent_hlist *hlist = swevent_hlist_deref(swhash); 7536 7537 if (!hlist) 7538 return; 7539 7540 RCU_INIT_POINTER(swhash->swevent_hlist, NULL); 7541 kfree_rcu(hlist, rcu_head); 7542 } 7543 7544 static void swevent_hlist_put_cpu(int cpu) 7545 { 7546 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 7547 7548 mutex_lock(&swhash->hlist_mutex); 7549 7550 if (!--swhash->hlist_refcount) 7551 swevent_hlist_release(swhash); 7552 7553 mutex_unlock(&swhash->hlist_mutex); 7554 } 7555 7556 static void swevent_hlist_put(void) 7557 { 7558 int cpu; 7559 7560 for_each_possible_cpu(cpu) 7561 swevent_hlist_put_cpu(cpu); 7562 } 7563 7564 static int swevent_hlist_get_cpu(int cpu) 7565 { 7566 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 7567 int err = 0; 7568 7569 mutex_lock(&swhash->hlist_mutex); 7570 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) { 7571 struct swevent_hlist *hlist; 7572 7573 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL); 7574 if (!hlist) { 7575 err = -ENOMEM; 7576 goto exit; 7577 } 7578 rcu_assign_pointer(swhash->swevent_hlist, hlist); 7579 } 7580 swhash->hlist_refcount++; 7581 exit: 7582 mutex_unlock(&swhash->hlist_mutex); 7583 7584 return err; 7585 } 7586 7587 static int swevent_hlist_get(void) 7588 { 7589 int err, cpu, failed_cpu; 7590 7591 get_online_cpus(); 7592 for_each_possible_cpu(cpu) { 7593 err = swevent_hlist_get_cpu(cpu); 7594 if (err) { 7595 failed_cpu = cpu; 7596 goto fail; 7597 } 7598 } 7599 put_online_cpus(); 7600 7601 return 0; 7602 fail: 7603 for_each_possible_cpu(cpu) { 7604 if (cpu == failed_cpu) 7605 break; 7606 swevent_hlist_put_cpu(cpu); 7607 } 7608 7609 put_online_cpus(); 7610 return err; 7611 } 7612 7613 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX]; 7614 7615 static void sw_perf_event_destroy(struct perf_event *event) 7616 { 7617 u64 event_id = event->attr.config; 7618 7619 WARN_ON(event->parent); 7620 7621 static_key_slow_dec(&perf_swevent_enabled[event_id]); 7622 swevent_hlist_put(); 7623 } 7624 7625 static int perf_swevent_init(struct perf_event *event) 7626 { 7627 u64 event_id = event->attr.config; 7628 7629 if (event->attr.type != PERF_TYPE_SOFTWARE) 7630 return -ENOENT; 7631 7632 /* 7633 * no branch sampling for software events 7634 */ 7635 if (has_branch_stack(event)) 7636 return -EOPNOTSUPP; 7637 7638 switch (event_id) { 7639 case PERF_COUNT_SW_CPU_CLOCK: 7640 case PERF_COUNT_SW_TASK_CLOCK: 7641 return -ENOENT; 7642 7643 default: 7644 break; 7645 } 7646 7647 if (event_id >= PERF_COUNT_SW_MAX) 7648 return -ENOENT; 7649 7650 if (!event->parent) { 7651 int err; 7652 7653 err = swevent_hlist_get(); 7654 if (err) 7655 return err; 7656 7657 static_key_slow_inc(&perf_swevent_enabled[event_id]); 7658 event->destroy = sw_perf_event_destroy; 7659 } 7660 7661 return 0; 7662 } 7663 7664 static struct pmu perf_swevent = { 7665 .task_ctx_nr = perf_sw_context, 7666 7667 .capabilities = PERF_PMU_CAP_NO_NMI, 7668 7669 .event_init = perf_swevent_init, 7670 .add = perf_swevent_add, 7671 .del = perf_swevent_del, 7672 .start = perf_swevent_start, 7673 .stop = perf_swevent_stop, 7674 .read = perf_swevent_read, 7675 }; 7676 7677 #ifdef CONFIG_EVENT_TRACING 7678 7679 static int perf_tp_filter_match(struct perf_event *event, 7680 struct perf_sample_data *data) 7681 { 7682 void *record = data->raw->frag.data; 7683 7684 /* only top level events have filters set */ 7685 if (event->parent) 7686 event = event->parent; 7687 7688 if (likely(!event->filter) || filter_match_preds(event->filter, record)) 7689 return 1; 7690 return 0; 7691 } 7692 7693 static int perf_tp_event_match(struct perf_event *event, 7694 struct perf_sample_data *data, 7695 struct pt_regs *regs) 7696 { 7697 if (event->hw.state & PERF_HES_STOPPED) 7698 return 0; 7699 /* 7700 * All tracepoints are from kernel-space. 7701 */ 7702 if (event->attr.exclude_kernel) 7703 return 0; 7704 7705 if (!perf_tp_filter_match(event, data)) 7706 return 0; 7707 7708 return 1; 7709 } 7710 7711 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx, 7712 struct trace_event_call *call, u64 count, 7713 struct pt_regs *regs, struct hlist_head *head, 7714 struct task_struct *task) 7715 { 7716 struct bpf_prog *prog = call->prog; 7717 7718 if (prog) { 7719 *(struct pt_regs **)raw_data = regs; 7720 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) { 7721 perf_swevent_put_recursion_context(rctx); 7722 return; 7723 } 7724 } 7725 perf_tp_event(call->event.type, count, raw_data, size, regs, head, 7726 rctx, task); 7727 } 7728 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit); 7729 7730 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size, 7731 struct pt_regs *regs, struct hlist_head *head, int rctx, 7732 struct task_struct *task) 7733 { 7734 struct perf_sample_data data; 7735 struct perf_event *event; 7736 7737 struct perf_raw_record raw = { 7738 .frag = { 7739 .size = entry_size, 7740 .data = record, 7741 }, 7742 }; 7743 7744 perf_sample_data_init(&data, 0, 0); 7745 data.raw = &raw; 7746 7747 perf_trace_buf_update(record, event_type); 7748 7749 hlist_for_each_entry_rcu(event, head, hlist_entry) { 7750 if (perf_tp_event_match(event, &data, regs)) 7751 perf_swevent_event(event, count, &data, regs); 7752 } 7753 7754 /* 7755 * If we got specified a target task, also iterate its context and 7756 * deliver this event there too. 7757 */ 7758 if (task && task != current) { 7759 struct perf_event_context *ctx; 7760 struct trace_entry *entry = record; 7761 7762 rcu_read_lock(); 7763 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]); 7764 if (!ctx) 7765 goto unlock; 7766 7767 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 7768 if (event->attr.type != PERF_TYPE_TRACEPOINT) 7769 continue; 7770 if (event->attr.config != entry->type) 7771 continue; 7772 if (perf_tp_event_match(event, &data, regs)) 7773 perf_swevent_event(event, count, &data, regs); 7774 } 7775 unlock: 7776 rcu_read_unlock(); 7777 } 7778 7779 perf_swevent_put_recursion_context(rctx); 7780 } 7781 EXPORT_SYMBOL_GPL(perf_tp_event); 7782 7783 static void tp_perf_event_destroy(struct perf_event *event) 7784 { 7785 perf_trace_destroy(event); 7786 } 7787 7788 static int perf_tp_event_init(struct perf_event *event) 7789 { 7790 int err; 7791 7792 if (event->attr.type != PERF_TYPE_TRACEPOINT) 7793 return -ENOENT; 7794 7795 /* 7796 * no branch sampling for tracepoint events 7797 */ 7798 if (has_branch_stack(event)) 7799 return -EOPNOTSUPP; 7800 7801 err = perf_trace_init(event); 7802 if (err) 7803 return err; 7804 7805 event->destroy = tp_perf_event_destroy; 7806 7807 return 0; 7808 } 7809 7810 static struct pmu perf_tracepoint = { 7811 .task_ctx_nr = perf_sw_context, 7812 7813 .event_init = perf_tp_event_init, 7814 .add = perf_trace_add, 7815 .del = perf_trace_del, 7816 .start = perf_swevent_start, 7817 .stop = perf_swevent_stop, 7818 .read = perf_swevent_read, 7819 }; 7820 7821 static inline void perf_tp_register(void) 7822 { 7823 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT); 7824 } 7825 7826 static void perf_event_free_filter(struct perf_event *event) 7827 { 7828 ftrace_profile_free_filter(event); 7829 } 7830 7831 #ifdef CONFIG_BPF_SYSCALL 7832 static void bpf_overflow_handler(struct perf_event *event, 7833 struct perf_sample_data *data, 7834 struct pt_regs *regs) 7835 { 7836 struct bpf_perf_event_data_kern ctx = { 7837 .data = data, 7838 .regs = regs, 7839 }; 7840 int ret = 0; 7841 7842 preempt_disable(); 7843 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) 7844 goto out; 7845 rcu_read_lock(); 7846 ret = BPF_PROG_RUN(event->prog, &ctx); 7847 rcu_read_unlock(); 7848 out: 7849 __this_cpu_dec(bpf_prog_active); 7850 preempt_enable(); 7851 if (!ret) 7852 return; 7853 7854 event->orig_overflow_handler(event, data, regs); 7855 } 7856 7857 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd) 7858 { 7859 struct bpf_prog *prog; 7860 7861 if (event->overflow_handler_context) 7862 /* hw breakpoint or kernel counter */ 7863 return -EINVAL; 7864 7865 if (event->prog) 7866 return -EEXIST; 7867 7868 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT); 7869 if (IS_ERR(prog)) 7870 return PTR_ERR(prog); 7871 7872 event->prog = prog; 7873 event->orig_overflow_handler = READ_ONCE(event->overflow_handler); 7874 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler); 7875 return 0; 7876 } 7877 7878 static void perf_event_free_bpf_handler(struct perf_event *event) 7879 { 7880 struct bpf_prog *prog = event->prog; 7881 7882 if (!prog) 7883 return; 7884 7885 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler); 7886 event->prog = NULL; 7887 bpf_prog_put(prog); 7888 } 7889 #else 7890 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd) 7891 { 7892 return -EOPNOTSUPP; 7893 } 7894 static void perf_event_free_bpf_handler(struct perf_event *event) 7895 { 7896 } 7897 #endif 7898 7899 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) 7900 { 7901 bool is_kprobe, is_tracepoint; 7902 struct bpf_prog *prog; 7903 7904 if (event->attr.type == PERF_TYPE_HARDWARE || 7905 event->attr.type == PERF_TYPE_SOFTWARE) 7906 return perf_event_set_bpf_handler(event, prog_fd); 7907 7908 if (event->attr.type != PERF_TYPE_TRACEPOINT) 7909 return -EINVAL; 7910 7911 if (event->tp_event->prog) 7912 return -EEXIST; 7913 7914 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE; 7915 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT; 7916 if (!is_kprobe && !is_tracepoint) 7917 /* bpf programs can only be attached to u/kprobe or tracepoint */ 7918 return -EINVAL; 7919 7920 prog = bpf_prog_get(prog_fd); 7921 if (IS_ERR(prog)) 7922 return PTR_ERR(prog); 7923 7924 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) || 7925 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT)) { 7926 /* valid fd, but invalid bpf program type */ 7927 bpf_prog_put(prog); 7928 return -EINVAL; 7929 } 7930 7931 if (is_tracepoint) { 7932 int off = trace_event_get_offsets(event->tp_event); 7933 7934 if (prog->aux->max_ctx_offset > off) { 7935 bpf_prog_put(prog); 7936 return -EACCES; 7937 } 7938 } 7939 event->tp_event->prog = prog; 7940 7941 return 0; 7942 } 7943 7944 static void perf_event_free_bpf_prog(struct perf_event *event) 7945 { 7946 struct bpf_prog *prog; 7947 7948 perf_event_free_bpf_handler(event); 7949 7950 if (!event->tp_event) 7951 return; 7952 7953 prog = event->tp_event->prog; 7954 if (prog) { 7955 event->tp_event->prog = NULL; 7956 bpf_prog_put(prog); 7957 } 7958 } 7959 7960 #else 7961 7962 static inline void perf_tp_register(void) 7963 { 7964 } 7965 7966 static void perf_event_free_filter(struct perf_event *event) 7967 { 7968 } 7969 7970 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) 7971 { 7972 return -ENOENT; 7973 } 7974 7975 static void perf_event_free_bpf_prog(struct perf_event *event) 7976 { 7977 } 7978 #endif /* CONFIG_EVENT_TRACING */ 7979 7980 #ifdef CONFIG_HAVE_HW_BREAKPOINT 7981 void perf_bp_event(struct perf_event *bp, void *data) 7982 { 7983 struct perf_sample_data sample; 7984 struct pt_regs *regs = data; 7985 7986 perf_sample_data_init(&sample, bp->attr.bp_addr, 0); 7987 7988 if (!bp->hw.state && !perf_exclude_event(bp, regs)) 7989 perf_swevent_event(bp, 1, &sample, regs); 7990 } 7991 #endif 7992 7993 /* 7994 * Allocate a new address filter 7995 */ 7996 static struct perf_addr_filter * 7997 perf_addr_filter_new(struct perf_event *event, struct list_head *filters) 7998 { 7999 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu); 8000 struct perf_addr_filter *filter; 8001 8002 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node); 8003 if (!filter) 8004 return NULL; 8005 8006 INIT_LIST_HEAD(&filter->entry); 8007 list_add_tail(&filter->entry, filters); 8008 8009 return filter; 8010 } 8011 8012 static void free_filters_list(struct list_head *filters) 8013 { 8014 struct perf_addr_filter *filter, *iter; 8015 8016 list_for_each_entry_safe(filter, iter, filters, entry) { 8017 if (filter->inode) 8018 iput(filter->inode); 8019 list_del(&filter->entry); 8020 kfree(filter); 8021 } 8022 } 8023 8024 /* 8025 * Free existing address filters and optionally install new ones 8026 */ 8027 static void perf_addr_filters_splice(struct perf_event *event, 8028 struct list_head *head) 8029 { 8030 unsigned long flags; 8031 LIST_HEAD(list); 8032 8033 if (!has_addr_filter(event)) 8034 return; 8035 8036 /* don't bother with children, they don't have their own filters */ 8037 if (event->parent) 8038 return; 8039 8040 raw_spin_lock_irqsave(&event->addr_filters.lock, flags); 8041 8042 list_splice_init(&event->addr_filters.list, &list); 8043 if (head) 8044 list_splice(head, &event->addr_filters.list); 8045 8046 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags); 8047 8048 free_filters_list(&list); 8049 } 8050 8051 /* 8052 * Scan through mm's vmas and see if one of them matches the 8053 * @filter; if so, adjust filter's address range. 8054 * Called with mm::mmap_sem down for reading. 8055 */ 8056 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter, 8057 struct mm_struct *mm) 8058 { 8059 struct vm_area_struct *vma; 8060 8061 for (vma = mm->mmap; vma; vma = vma->vm_next) { 8062 struct file *file = vma->vm_file; 8063 unsigned long off = vma->vm_pgoff << PAGE_SHIFT; 8064 unsigned long vma_size = vma->vm_end - vma->vm_start; 8065 8066 if (!file) 8067 continue; 8068 8069 if (!perf_addr_filter_match(filter, file, off, vma_size)) 8070 continue; 8071 8072 return vma->vm_start; 8073 } 8074 8075 return 0; 8076 } 8077 8078 /* 8079 * Update event's address range filters based on the 8080 * task's existing mappings, if any. 8081 */ 8082 static void perf_event_addr_filters_apply(struct perf_event *event) 8083 { 8084 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 8085 struct task_struct *task = READ_ONCE(event->ctx->task); 8086 struct perf_addr_filter *filter; 8087 struct mm_struct *mm = NULL; 8088 unsigned int count = 0; 8089 unsigned long flags; 8090 8091 /* 8092 * We may observe TASK_TOMBSTONE, which means that the event tear-down 8093 * will stop on the parent's child_mutex that our caller is also holding 8094 */ 8095 if (task == TASK_TOMBSTONE) 8096 return; 8097 8098 if (!ifh->nr_file_filters) 8099 return; 8100 8101 mm = get_task_mm(event->ctx->task); 8102 if (!mm) 8103 goto restart; 8104 8105 down_read(&mm->mmap_sem); 8106 8107 raw_spin_lock_irqsave(&ifh->lock, flags); 8108 list_for_each_entry(filter, &ifh->list, entry) { 8109 event->addr_filters_offs[count] = 0; 8110 8111 /* 8112 * Adjust base offset if the filter is associated to a binary 8113 * that needs to be mapped: 8114 */ 8115 if (filter->inode) 8116 event->addr_filters_offs[count] = 8117 perf_addr_filter_apply(filter, mm); 8118 8119 count++; 8120 } 8121 8122 event->addr_filters_gen++; 8123 raw_spin_unlock_irqrestore(&ifh->lock, flags); 8124 8125 up_read(&mm->mmap_sem); 8126 8127 mmput(mm); 8128 8129 restart: 8130 perf_event_stop(event, 1); 8131 } 8132 8133 /* 8134 * Address range filtering: limiting the data to certain 8135 * instruction address ranges. Filters are ioctl()ed to us from 8136 * userspace as ascii strings. 8137 * 8138 * Filter string format: 8139 * 8140 * ACTION RANGE_SPEC 8141 * where ACTION is one of the 8142 * * "filter": limit the trace to this region 8143 * * "start": start tracing from this address 8144 * * "stop": stop tracing at this address/region; 8145 * RANGE_SPEC is 8146 * * for kernel addresses: <start address>[/<size>] 8147 * * for object files: <start address>[/<size>]@</path/to/object/file> 8148 * 8149 * if <size> is not specified, the range is treated as a single address. 8150 */ 8151 enum { 8152 IF_ACT_NONE = -1, 8153 IF_ACT_FILTER, 8154 IF_ACT_START, 8155 IF_ACT_STOP, 8156 IF_SRC_FILE, 8157 IF_SRC_KERNEL, 8158 IF_SRC_FILEADDR, 8159 IF_SRC_KERNELADDR, 8160 }; 8161 8162 enum { 8163 IF_STATE_ACTION = 0, 8164 IF_STATE_SOURCE, 8165 IF_STATE_END, 8166 }; 8167 8168 static const match_table_t if_tokens = { 8169 { IF_ACT_FILTER, "filter" }, 8170 { IF_ACT_START, "start" }, 8171 { IF_ACT_STOP, "stop" }, 8172 { IF_SRC_FILE, "%u/%u@%s" }, 8173 { IF_SRC_KERNEL, "%u/%u" }, 8174 { IF_SRC_FILEADDR, "%u@%s" }, 8175 { IF_SRC_KERNELADDR, "%u" }, 8176 { IF_ACT_NONE, NULL }, 8177 }; 8178 8179 /* 8180 * Address filter string parser 8181 */ 8182 static int 8183 perf_event_parse_addr_filter(struct perf_event *event, char *fstr, 8184 struct list_head *filters) 8185 { 8186 struct perf_addr_filter *filter = NULL; 8187 char *start, *orig, *filename = NULL; 8188 struct path path; 8189 substring_t args[MAX_OPT_ARGS]; 8190 int state = IF_STATE_ACTION, token; 8191 unsigned int kernel = 0; 8192 int ret = -EINVAL; 8193 8194 orig = fstr = kstrdup(fstr, GFP_KERNEL); 8195 if (!fstr) 8196 return -ENOMEM; 8197 8198 while ((start = strsep(&fstr, " ,\n")) != NULL) { 8199 ret = -EINVAL; 8200 8201 if (!*start) 8202 continue; 8203 8204 /* filter definition begins */ 8205 if (state == IF_STATE_ACTION) { 8206 filter = perf_addr_filter_new(event, filters); 8207 if (!filter) 8208 goto fail; 8209 } 8210 8211 token = match_token(start, if_tokens, args); 8212 switch (token) { 8213 case IF_ACT_FILTER: 8214 case IF_ACT_START: 8215 filter->filter = 1; 8216 8217 case IF_ACT_STOP: 8218 if (state != IF_STATE_ACTION) 8219 goto fail; 8220 8221 state = IF_STATE_SOURCE; 8222 break; 8223 8224 case IF_SRC_KERNELADDR: 8225 case IF_SRC_KERNEL: 8226 kernel = 1; 8227 8228 case IF_SRC_FILEADDR: 8229 case IF_SRC_FILE: 8230 if (state != IF_STATE_SOURCE) 8231 goto fail; 8232 8233 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL) 8234 filter->range = 1; 8235 8236 *args[0].to = 0; 8237 ret = kstrtoul(args[0].from, 0, &filter->offset); 8238 if (ret) 8239 goto fail; 8240 8241 if (filter->range) { 8242 *args[1].to = 0; 8243 ret = kstrtoul(args[1].from, 0, &filter->size); 8244 if (ret) 8245 goto fail; 8246 } 8247 8248 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) { 8249 int fpos = filter->range ? 2 : 1; 8250 8251 filename = match_strdup(&args[fpos]); 8252 if (!filename) { 8253 ret = -ENOMEM; 8254 goto fail; 8255 } 8256 } 8257 8258 state = IF_STATE_END; 8259 break; 8260 8261 default: 8262 goto fail; 8263 } 8264 8265 /* 8266 * Filter definition is fully parsed, validate and install it. 8267 * Make sure that it doesn't contradict itself or the event's 8268 * attribute. 8269 */ 8270 if (state == IF_STATE_END) { 8271 ret = -EINVAL; 8272 if (kernel && event->attr.exclude_kernel) 8273 goto fail; 8274 8275 if (!kernel) { 8276 if (!filename) 8277 goto fail; 8278 8279 /* 8280 * For now, we only support file-based filters 8281 * in per-task events; doing so for CPU-wide 8282 * events requires additional context switching 8283 * trickery, since same object code will be 8284 * mapped at different virtual addresses in 8285 * different processes. 8286 */ 8287 ret = -EOPNOTSUPP; 8288 if (!event->ctx->task) 8289 goto fail_free_name; 8290 8291 /* look up the path and grab its inode */ 8292 ret = kern_path(filename, LOOKUP_FOLLOW, &path); 8293 if (ret) 8294 goto fail_free_name; 8295 8296 filter->inode = igrab(d_inode(path.dentry)); 8297 path_put(&path); 8298 kfree(filename); 8299 filename = NULL; 8300 8301 ret = -EINVAL; 8302 if (!filter->inode || 8303 !S_ISREG(filter->inode->i_mode)) 8304 /* free_filters_list() will iput() */ 8305 goto fail; 8306 8307 event->addr_filters.nr_file_filters++; 8308 } 8309 8310 /* ready to consume more filters */ 8311 state = IF_STATE_ACTION; 8312 filter = NULL; 8313 } 8314 } 8315 8316 if (state != IF_STATE_ACTION) 8317 goto fail; 8318 8319 kfree(orig); 8320 8321 return 0; 8322 8323 fail_free_name: 8324 kfree(filename); 8325 fail: 8326 free_filters_list(filters); 8327 kfree(orig); 8328 8329 return ret; 8330 } 8331 8332 static int 8333 perf_event_set_addr_filter(struct perf_event *event, char *filter_str) 8334 { 8335 LIST_HEAD(filters); 8336 int ret; 8337 8338 /* 8339 * Since this is called in perf_ioctl() path, we're already holding 8340 * ctx::mutex. 8341 */ 8342 lockdep_assert_held(&event->ctx->mutex); 8343 8344 if (WARN_ON_ONCE(event->parent)) 8345 return -EINVAL; 8346 8347 ret = perf_event_parse_addr_filter(event, filter_str, &filters); 8348 if (ret) 8349 goto fail_clear_files; 8350 8351 ret = event->pmu->addr_filters_validate(&filters); 8352 if (ret) 8353 goto fail_free_filters; 8354 8355 /* remove existing filters, if any */ 8356 perf_addr_filters_splice(event, &filters); 8357 8358 /* install new filters */ 8359 perf_event_for_each_child(event, perf_event_addr_filters_apply); 8360 8361 return ret; 8362 8363 fail_free_filters: 8364 free_filters_list(&filters); 8365 8366 fail_clear_files: 8367 event->addr_filters.nr_file_filters = 0; 8368 8369 return ret; 8370 } 8371 8372 static int perf_event_set_filter(struct perf_event *event, void __user *arg) 8373 { 8374 char *filter_str; 8375 int ret = -EINVAL; 8376 8377 if ((event->attr.type != PERF_TYPE_TRACEPOINT || 8378 !IS_ENABLED(CONFIG_EVENT_TRACING)) && 8379 !has_addr_filter(event)) 8380 return -EINVAL; 8381 8382 filter_str = strndup_user(arg, PAGE_SIZE); 8383 if (IS_ERR(filter_str)) 8384 return PTR_ERR(filter_str); 8385 8386 if (IS_ENABLED(CONFIG_EVENT_TRACING) && 8387 event->attr.type == PERF_TYPE_TRACEPOINT) 8388 ret = ftrace_profile_set_filter(event, event->attr.config, 8389 filter_str); 8390 else if (has_addr_filter(event)) 8391 ret = perf_event_set_addr_filter(event, filter_str); 8392 8393 kfree(filter_str); 8394 return ret; 8395 } 8396 8397 /* 8398 * hrtimer based swevent callback 8399 */ 8400 8401 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer) 8402 { 8403 enum hrtimer_restart ret = HRTIMER_RESTART; 8404 struct perf_sample_data data; 8405 struct pt_regs *regs; 8406 struct perf_event *event; 8407 u64 period; 8408 8409 event = container_of(hrtimer, struct perf_event, hw.hrtimer); 8410 8411 if (event->state != PERF_EVENT_STATE_ACTIVE) 8412 return HRTIMER_NORESTART; 8413 8414 event->pmu->read(event); 8415 8416 perf_sample_data_init(&data, 0, event->hw.last_period); 8417 regs = get_irq_regs(); 8418 8419 if (regs && !perf_exclude_event(event, regs)) { 8420 if (!(event->attr.exclude_idle && is_idle_task(current))) 8421 if (__perf_event_overflow(event, 1, &data, regs)) 8422 ret = HRTIMER_NORESTART; 8423 } 8424 8425 period = max_t(u64, 10000, event->hw.sample_period); 8426 hrtimer_forward_now(hrtimer, ns_to_ktime(period)); 8427 8428 return ret; 8429 } 8430 8431 static void perf_swevent_start_hrtimer(struct perf_event *event) 8432 { 8433 struct hw_perf_event *hwc = &event->hw; 8434 s64 period; 8435 8436 if (!is_sampling_event(event)) 8437 return; 8438 8439 period = local64_read(&hwc->period_left); 8440 if (period) { 8441 if (period < 0) 8442 period = 10000; 8443 8444 local64_set(&hwc->period_left, 0); 8445 } else { 8446 period = max_t(u64, 10000, hwc->sample_period); 8447 } 8448 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period), 8449 HRTIMER_MODE_REL_PINNED); 8450 } 8451 8452 static void perf_swevent_cancel_hrtimer(struct perf_event *event) 8453 { 8454 struct hw_perf_event *hwc = &event->hw; 8455 8456 if (is_sampling_event(event)) { 8457 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer); 8458 local64_set(&hwc->period_left, ktime_to_ns(remaining)); 8459 8460 hrtimer_cancel(&hwc->hrtimer); 8461 } 8462 } 8463 8464 static void perf_swevent_init_hrtimer(struct perf_event *event) 8465 { 8466 struct hw_perf_event *hwc = &event->hw; 8467 8468 if (!is_sampling_event(event)) 8469 return; 8470 8471 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 8472 hwc->hrtimer.function = perf_swevent_hrtimer; 8473 8474 /* 8475 * Since hrtimers have a fixed rate, we can do a static freq->period 8476 * mapping and avoid the whole period adjust feedback stuff. 8477 */ 8478 if (event->attr.freq) { 8479 long freq = event->attr.sample_freq; 8480 8481 event->attr.sample_period = NSEC_PER_SEC / freq; 8482 hwc->sample_period = event->attr.sample_period; 8483 local64_set(&hwc->period_left, hwc->sample_period); 8484 hwc->last_period = hwc->sample_period; 8485 event->attr.freq = 0; 8486 } 8487 } 8488 8489 /* 8490 * Software event: cpu wall time clock 8491 */ 8492 8493 static void cpu_clock_event_update(struct perf_event *event) 8494 { 8495 s64 prev; 8496 u64 now; 8497 8498 now = local_clock(); 8499 prev = local64_xchg(&event->hw.prev_count, now); 8500 local64_add(now - prev, &event->count); 8501 } 8502 8503 static void cpu_clock_event_start(struct perf_event *event, int flags) 8504 { 8505 local64_set(&event->hw.prev_count, local_clock()); 8506 perf_swevent_start_hrtimer(event); 8507 } 8508 8509 static void cpu_clock_event_stop(struct perf_event *event, int flags) 8510 { 8511 perf_swevent_cancel_hrtimer(event); 8512 cpu_clock_event_update(event); 8513 } 8514 8515 static int cpu_clock_event_add(struct perf_event *event, int flags) 8516 { 8517 if (flags & PERF_EF_START) 8518 cpu_clock_event_start(event, flags); 8519 perf_event_update_userpage(event); 8520 8521 return 0; 8522 } 8523 8524 static void cpu_clock_event_del(struct perf_event *event, int flags) 8525 { 8526 cpu_clock_event_stop(event, flags); 8527 } 8528 8529 static void cpu_clock_event_read(struct perf_event *event) 8530 { 8531 cpu_clock_event_update(event); 8532 } 8533 8534 static int cpu_clock_event_init(struct perf_event *event) 8535 { 8536 if (event->attr.type != PERF_TYPE_SOFTWARE) 8537 return -ENOENT; 8538 8539 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK) 8540 return -ENOENT; 8541 8542 /* 8543 * no branch sampling for software events 8544 */ 8545 if (has_branch_stack(event)) 8546 return -EOPNOTSUPP; 8547 8548 perf_swevent_init_hrtimer(event); 8549 8550 return 0; 8551 } 8552 8553 static struct pmu perf_cpu_clock = { 8554 .task_ctx_nr = perf_sw_context, 8555 8556 .capabilities = PERF_PMU_CAP_NO_NMI, 8557 8558 .event_init = cpu_clock_event_init, 8559 .add = cpu_clock_event_add, 8560 .del = cpu_clock_event_del, 8561 .start = cpu_clock_event_start, 8562 .stop = cpu_clock_event_stop, 8563 .read = cpu_clock_event_read, 8564 }; 8565 8566 /* 8567 * Software event: task time clock 8568 */ 8569 8570 static void task_clock_event_update(struct perf_event *event, u64 now) 8571 { 8572 u64 prev; 8573 s64 delta; 8574 8575 prev = local64_xchg(&event->hw.prev_count, now); 8576 delta = now - prev; 8577 local64_add(delta, &event->count); 8578 } 8579 8580 static void task_clock_event_start(struct perf_event *event, int flags) 8581 { 8582 local64_set(&event->hw.prev_count, event->ctx->time); 8583 perf_swevent_start_hrtimer(event); 8584 } 8585 8586 static void task_clock_event_stop(struct perf_event *event, int flags) 8587 { 8588 perf_swevent_cancel_hrtimer(event); 8589 task_clock_event_update(event, event->ctx->time); 8590 } 8591 8592 static int task_clock_event_add(struct perf_event *event, int flags) 8593 { 8594 if (flags & PERF_EF_START) 8595 task_clock_event_start(event, flags); 8596 perf_event_update_userpage(event); 8597 8598 return 0; 8599 } 8600 8601 static void task_clock_event_del(struct perf_event *event, int flags) 8602 { 8603 task_clock_event_stop(event, PERF_EF_UPDATE); 8604 } 8605 8606 static void task_clock_event_read(struct perf_event *event) 8607 { 8608 u64 now = perf_clock(); 8609 u64 delta = now - event->ctx->timestamp; 8610 u64 time = event->ctx->time + delta; 8611 8612 task_clock_event_update(event, time); 8613 } 8614 8615 static int task_clock_event_init(struct perf_event *event) 8616 { 8617 if (event->attr.type != PERF_TYPE_SOFTWARE) 8618 return -ENOENT; 8619 8620 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK) 8621 return -ENOENT; 8622 8623 /* 8624 * no branch sampling for software events 8625 */ 8626 if (has_branch_stack(event)) 8627 return -EOPNOTSUPP; 8628 8629 perf_swevent_init_hrtimer(event); 8630 8631 return 0; 8632 } 8633 8634 static struct pmu perf_task_clock = { 8635 .task_ctx_nr = perf_sw_context, 8636 8637 .capabilities = PERF_PMU_CAP_NO_NMI, 8638 8639 .event_init = task_clock_event_init, 8640 .add = task_clock_event_add, 8641 .del = task_clock_event_del, 8642 .start = task_clock_event_start, 8643 .stop = task_clock_event_stop, 8644 .read = task_clock_event_read, 8645 }; 8646 8647 static void perf_pmu_nop_void(struct pmu *pmu) 8648 { 8649 } 8650 8651 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags) 8652 { 8653 } 8654 8655 static int perf_pmu_nop_int(struct pmu *pmu) 8656 { 8657 return 0; 8658 } 8659 8660 static DEFINE_PER_CPU(unsigned int, nop_txn_flags); 8661 8662 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags) 8663 { 8664 __this_cpu_write(nop_txn_flags, flags); 8665 8666 if (flags & ~PERF_PMU_TXN_ADD) 8667 return; 8668 8669 perf_pmu_disable(pmu); 8670 } 8671 8672 static int perf_pmu_commit_txn(struct pmu *pmu) 8673 { 8674 unsigned int flags = __this_cpu_read(nop_txn_flags); 8675 8676 __this_cpu_write(nop_txn_flags, 0); 8677 8678 if (flags & ~PERF_PMU_TXN_ADD) 8679 return 0; 8680 8681 perf_pmu_enable(pmu); 8682 return 0; 8683 } 8684 8685 static void perf_pmu_cancel_txn(struct pmu *pmu) 8686 { 8687 unsigned int flags = __this_cpu_read(nop_txn_flags); 8688 8689 __this_cpu_write(nop_txn_flags, 0); 8690 8691 if (flags & ~PERF_PMU_TXN_ADD) 8692 return; 8693 8694 perf_pmu_enable(pmu); 8695 } 8696 8697 static int perf_event_idx_default(struct perf_event *event) 8698 { 8699 return 0; 8700 } 8701 8702 /* 8703 * Ensures all contexts with the same task_ctx_nr have the same 8704 * pmu_cpu_context too. 8705 */ 8706 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn) 8707 { 8708 struct pmu *pmu; 8709 8710 if (ctxn < 0) 8711 return NULL; 8712 8713 list_for_each_entry(pmu, &pmus, entry) { 8714 if (pmu->task_ctx_nr == ctxn) 8715 return pmu->pmu_cpu_context; 8716 } 8717 8718 return NULL; 8719 } 8720 8721 static void free_pmu_context(struct pmu *pmu) 8722 { 8723 mutex_lock(&pmus_lock); 8724 free_percpu(pmu->pmu_cpu_context); 8725 mutex_unlock(&pmus_lock); 8726 } 8727 8728 /* 8729 * Let userspace know that this PMU supports address range filtering: 8730 */ 8731 static ssize_t nr_addr_filters_show(struct device *dev, 8732 struct device_attribute *attr, 8733 char *page) 8734 { 8735 struct pmu *pmu = dev_get_drvdata(dev); 8736 8737 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters); 8738 } 8739 DEVICE_ATTR_RO(nr_addr_filters); 8740 8741 static struct idr pmu_idr; 8742 8743 static ssize_t 8744 type_show(struct device *dev, struct device_attribute *attr, char *page) 8745 { 8746 struct pmu *pmu = dev_get_drvdata(dev); 8747 8748 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type); 8749 } 8750 static DEVICE_ATTR_RO(type); 8751 8752 static ssize_t 8753 perf_event_mux_interval_ms_show(struct device *dev, 8754 struct device_attribute *attr, 8755 char *page) 8756 { 8757 struct pmu *pmu = dev_get_drvdata(dev); 8758 8759 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms); 8760 } 8761 8762 static DEFINE_MUTEX(mux_interval_mutex); 8763 8764 static ssize_t 8765 perf_event_mux_interval_ms_store(struct device *dev, 8766 struct device_attribute *attr, 8767 const char *buf, size_t count) 8768 { 8769 struct pmu *pmu = dev_get_drvdata(dev); 8770 int timer, cpu, ret; 8771 8772 ret = kstrtoint(buf, 0, &timer); 8773 if (ret) 8774 return ret; 8775 8776 if (timer < 1) 8777 return -EINVAL; 8778 8779 /* same value, noting to do */ 8780 if (timer == pmu->hrtimer_interval_ms) 8781 return count; 8782 8783 mutex_lock(&mux_interval_mutex); 8784 pmu->hrtimer_interval_ms = timer; 8785 8786 /* update all cpuctx for this PMU */ 8787 get_online_cpus(); 8788 for_each_online_cpu(cpu) { 8789 struct perf_cpu_context *cpuctx; 8790 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 8791 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer); 8792 8793 cpu_function_call(cpu, 8794 (remote_function_f)perf_mux_hrtimer_restart, cpuctx); 8795 } 8796 put_online_cpus(); 8797 mutex_unlock(&mux_interval_mutex); 8798 8799 return count; 8800 } 8801 static DEVICE_ATTR_RW(perf_event_mux_interval_ms); 8802 8803 static struct attribute *pmu_dev_attrs[] = { 8804 &dev_attr_type.attr, 8805 &dev_attr_perf_event_mux_interval_ms.attr, 8806 NULL, 8807 }; 8808 ATTRIBUTE_GROUPS(pmu_dev); 8809 8810 static int pmu_bus_running; 8811 static struct bus_type pmu_bus = { 8812 .name = "event_source", 8813 .dev_groups = pmu_dev_groups, 8814 }; 8815 8816 static void pmu_dev_release(struct device *dev) 8817 { 8818 kfree(dev); 8819 } 8820 8821 static int pmu_dev_alloc(struct pmu *pmu) 8822 { 8823 int ret = -ENOMEM; 8824 8825 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL); 8826 if (!pmu->dev) 8827 goto out; 8828 8829 pmu->dev->groups = pmu->attr_groups; 8830 device_initialize(pmu->dev); 8831 ret = dev_set_name(pmu->dev, "%s", pmu->name); 8832 if (ret) 8833 goto free_dev; 8834 8835 dev_set_drvdata(pmu->dev, pmu); 8836 pmu->dev->bus = &pmu_bus; 8837 pmu->dev->release = pmu_dev_release; 8838 ret = device_add(pmu->dev); 8839 if (ret) 8840 goto free_dev; 8841 8842 /* For PMUs with address filters, throw in an extra attribute: */ 8843 if (pmu->nr_addr_filters) 8844 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters); 8845 8846 if (ret) 8847 goto del_dev; 8848 8849 out: 8850 return ret; 8851 8852 del_dev: 8853 device_del(pmu->dev); 8854 8855 free_dev: 8856 put_device(pmu->dev); 8857 goto out; 8858 } 8859 8860 static struct lock_class_key cpuctx_mutex; 8861 static struct lock_class_key cpuctx_lock; 8862 8863 int perf_pmu_register(struct pmu *pmu, const char *name, int type) 8864 { 8865 int cpu, ret; 8866 8867 mutex_lock(&pmus_lock); 8868 ret = -ENOMEM; 8869 pmu->pmu_disable_count = alloc_percpu(int); 8870 if (!pmu->pmu_disable_count) 8871 goto unlock; 8872 8873 pmu->type = -1; 8874 if (!name) 8875 goto skip_type; 8876 pmu->name = name; 8877 8878 if (type < 0) { 8879 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL); 8880 if (type < 0) { 8881 ret = type; 8882 goto free_pdc; 8883 } 8884 } 8885 pmu->type = type; 8886 8887 if (pmu_bus_running) { 8888 ret = pmu_dev_alloc(pmu); 8889 if (ret) 8890 goto free_idr; 8891 } 8892 8893 skip_type: 8894 if (pmu->task_ctx_nr == perf_hw_context) { 8895 static int hw_context_taken = 0; 8896 8897 /* 8898 * Other than systems with heterogeneous CPUs, it never makes 8899 * sense for two PMUs to share perf_hw_context. PMUs which are 8900 * uncore must use perf_invalid_context. 8901 */ 8902 if (WARN_ON_ONCE(hw_context_taken && 8903 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS))) 8904 pmu->task_ctx_nr = perf_invalid_context; 8905 8906 hw_context_taken = 1; 8907 } 8908 8909 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr); 8910 if (pmu->pmu_cpu_context) 8911 goto got_cpu_context; 8912 8913 ret = -ENOMEM; 8914 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context); 8915 if (!pmu->pmu_cpu_context) 8916 goto free_dev; 8917 8918 for_each_possible_cpu(cpu) { 8919 struct perf_cpu_context *cpuctx; 8920 8921 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 8922 __perf_event_init_context(&cpuctx->ctx); 8923 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex); 8924 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock); 8925 cpuctx->ctx.pmu = pmu; 8926 8927 __perf_mux_hrtimer_init(cpuctx, cpu); 8928 } 8929 8930 got_cpu_context: 8931 if (!pmu->start_txn) { 8932 if (pmu->pmu_enable) { 8933 /* 8934 * If we have pmu_enable/pmu_disable calls, install 8935 * transaction stubs that use that to try and batch 8936 * hardware accesses. 8937 */ 8938 pmu->start_txn = perf_pmu_start_txn; 8939 pmu->commit_txn = perf_pmu_commit_txn; 8940 pmu->cancel_txn = perf_pmu_cancel_txn; 8941 } else { 8942 pmu->start_txn = perf_pmu_nop_txn; 8943 pmu->commit_txn = perf_pmu_nop_int; 8944 pmu->cancel_txn = perf_pmu_nop_void; 8945 } 8946 } 8947 8948 if (!pmu->pmu_enable) { 8949 pmu->pmu_enable = perf_pmu_nop_void; 8950 pmu->pmu_disable = perf_pmu_nop_void; 8951 } 8952 8953 if (!pmu->event_idx) 8954 pmu->event_idx = perf_event_idx_default; 8955 8956 list_add_rcu(&pmu->entry, &pmus); 8957 atomic_set(&pmu->exclusive_cnt, 0); 8958 ret = 0; 8959 unlock: 8960 mutex_unlock(&pmus_lock); 8961 8962 return ret; 8963 8964 free_dev: 8965 device_del(pmu->dev); 8966 put_device(pmu->dev); 8967 8968 free_idr: 8969 if (pmu->type >= PERF_TYPE_MAX) 8970 idr_remove(&pmu_idr, pmu->type); 8971 8972 free_pdc: 8973 free_percpu(pmu->pmu_disable_count); 8974 goto unlock; 8975 } 8976 EXPORT_SYMBOL_GPL(perf_pmu_register); 8977 8978 void perf_pmu_unregister(struct pmu *pmu) 8979 { 8980 int remove_device; 8981 8982 mutex_lock(&pmus_lock); 8983 remove_device = pmu_bus_running; 8984 list_del_rcu(&pmu->entry); 8985 mutex_unlock(&pmus_lock); 8986 8987 /* 8988 * We dereference the pmu list under both SRCU and regular RCU, so 8989 * synchronize against both of those. 8990 */ 8991 synchronize_srcu(&pmus_srcu); 8992 synchronize_rcu(); 8993 8994 free_percpu(pmu->pmu_disable_count); 8995 if (pmu->type >= PERF_TYPE_MAX) 8996 idr_remove(&pmu_idr, pmu->type); 8997 if (remove_device) { 8998 if (pmu->nr_addr_filters) 8999 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters); 9000 device_del(pmu->dev); 9001 put_device(pmu->dev); 9002 } 9003 free_pmu_context(pmu); 9004 } 9005 EXPORT_SYMBOL_GPL(perf_pmu_unregister); 9006 9007 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event) 9008 { 9009 struct perf_event_context *ctx = NULL; 9010 int ret; 9011 9012 if (!try_module_get(pmu->module)) 9013 return -ENODEV; 9014 9015 if (event->group_leader != event) { 9016 /* 9017 * This ctx->mutex can nest when we're called through 9018 * inheritance. See the perf_event_ctx_lock_nested() comment. 9019 */ 9020 ctx = perf_event_ctx_lock_nested(event->group_leader, 9021 SINGLE_DEPTH_NESTING); 9022 BUG_ON(!ctx); 9023 } 9024 9025 event->pmu = pmu; 9026 ret = pmu->event_init(event); 9027 9028 if (ctx) 9029 perf_event_ctx_unlock(event->group_leader, ctx); 9030 9031 if (ret) 9032 module_put(pmu->module); 9033 9034 return ret; 9035 } 9036 9037 static struct pmu *perf_init_event(struct perf_event *event) 9038 { 9039 struct pmu *pmu = NULL; 9040 int idx; 9041 int ret; 9042 9043 idx = srcu_read_lock(&pmus_srcu); 9044 9045 /* Try parent's PMU first: */ 9046 if (event->parent && event->parent->pmu) { 9047 pmu = event->parent->pmu; 9048 ret = perf_try_init_event(pmu, event); 9049 if (!ret) 9050 goto unlock; 9051 } 9052 9053 rcu_read_lock(); 9054 pmu = idr_find(&pmu_idr, event->attr.type); 9055 rcu_read_unlock(); 9056 if (pmu) { 9057 ret = perf_try_init_event(pmu, event); 9058 if (ret) 9059 pmu = ERR_PTR(ret); 9060 goto unlock; 9061 } 9062 9063 list_for_each_entry_rcu(pmu, &pmus, entry) { 9064 ret = perf_try_init_event(pmu, event); 9065 if (!ret) 9066 goto unlock; 9067 9068 if (ret != -ENOENT) { 9069 pmu = ERR_PTR(ret); 9070 goto unlock; 9071 } 9072 } 9073 pmu = ERR_PTR(-ENOENT); 9074 unlock: 9075 srcu_read_unlock(&pmus_srcu, idx); 9076 9077 return pmu; 9078 } 9079 9080 static void attach_sb_event(struct perf_event *event) 9081 { 9082 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu); 9083 9084 raw_spin_lock(&pel->lock); 9085 list_add_rcu(&event->sb_list, &pel->list); 9086 raw_spin_unlock(&pel->lock); 9087 } 9088 9089 /* 9090 * We keep a list of all !task (and therefore per-cpu) events 9091 * that need to receive side-band records. 9092 * 9093 * This avoids having to scan all the various PMU per-cpu contexts 9094 * looking for them. 9095 */ 9096 static void account_pmu_sb_event(struct perf_event *event) 9097 { 9098 if (is_sb_event(event)) 9099 attach_sb_event(event); 9100 } 9101 9102 static void account_event_cpu(struct perf_event *event, int cpu) 9103 { 9104 if (event->parent) 9105 return; 9106 9107 if (is_cgroup_event(event)) 9108 atomic_inc(&per_cpu(perf_cgroup_events, cpu)); 9109 } 9110 9111 /* Freq events need the tick to stay alive (see perf_event_task_tick). */ 9112 static void account_freq_event_nohz(void) 9113 { 9114 #ifdef CONFIG_NO_HZ_FULL 9115 /* Lock so we don't race with concurrent unaccount */ 9116 spin_lock(&nr_freq_lock); 9117 if (atomic_inc_return(&nr_freq_events) == 1) 9118 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS); 9119 spin_unlock(&nr_freq_lock); 9120 #endif 9121 } 9122 9123 static void account_freq_event(void) 9124 { 9125 if (tick_nohz_full_enabled()) 9126 account_freq_event_nohz(); 9127 else 9128 atomic_inc(&nr_freq_events); 9129 } 9130 9131 9132 static void account_event(struct perf_event *event) 9133 { 9134 bool inc = false; 9135 9136 if (event->parent) 9137 return; 9138 9139 if (event->attach_state & PERF_ATTACH_TASK) 9140 inc = true; 9141 if (event->attr.mmap || event->attr.mmap_data) 9142 atomic_inc(&nr_mmap_events); 9143 if (event->attr.comm) 9144 atomic_inc(&nr_comm_events); 9145 if (event->attr.task) 9146 atomic_inc(&nr_task_events); 9147 if (event->attr.freq) 9148 account_freq_event(); 9149 if (event->attr.context_switch) { 9150 atomic_inc(&nr_switch_events); 9151 inc = true; 9152 } 9153 if (has_branch_stack(event)) 9154 inc = true; 9155 if (is_cgroup_event(event)) 9156 inc = true; 9157 9158 if (inc) { 9159 if (atomic_inc_not_zero(&perf_sched_count)) 9160 goto enabled; 9161 9162 mutex_lock(&perf_sched_mutex); 9163 if (!atomic_read(&perf_sched_count)) { 9164 static_branch_enable(&perf_sched_events); 9165 /* 9166 * Guarantee that all CPUs observe they key change and 9167 * call the perf scheduling hooks before proceeding to 9168 * install events that need them. 9169 */ 9170 synchronize_sched(); 9171 } 9172 /* 9173 * Now that we have waited for the sync_sched(), allow further 9174 * increments to by-pass the mutex. 9175 */ 9176 atomic_inc(&perf_sched_count); 9177 mutex_unlock(&perf_sched_mutex); 9178 } 9179 enabled: 9180 9181 account_event_cpu(event, event->cpu); 9182 9183 account_pmu_sb_event(event); 9184 } 9185 9186 /* 9187 * Allocate and initialize a event structure 9188 */ 9189 static struct perf_event * 9190 perf_event_alloc(struct perf_event_attr *attr, int cpu, 9191 struct task_struct *task, 9192 struct perf_event *group_leader, 9193 struct perf_event *parent_event, 9194 perf_overflow_handler_t overflow_handler, 9195 void *context, int cgroup_fd) 9196 { 9197 struct pmu *pmu; 9198 struct perf_event *event; 9199 struct hw_perf_event *hwc; 9200 long err = -EINVAL; 9201 9202 if ((unsigned)cpu >= nr_cpu_ids) { 9203 if (!task || cpu != -1) 9204 return ERR_PTR(-EINVAL); 9205 } 9206 9207 event = kzalloc(sizeof(*event), GFP_KERNEL); 9208 if (!event) 9209 return ERR_PTR(-ENOMEM); 9210 9211 /* 9212 * Single events are their own group leaders, with an 9213 * empty sibling list: 9214 */ 9215 if (!group_leader) 9216 group_leader = event; 9217 9218 mutex_init(&event->child_mutex); 9219 INIT_LIST_HEAD(&event->child_list); 9220 9221 INIT_LIST_HEAD(&event->group_entry); 9222 INIT_LIST_HEAD(&event->event_entry); 9223 INIT_LIST_HEAD(&event->sibling_list); 9224 INIT_LIST_HEAD(&event->rb_entry); 9225 INIT_LIST_HEAD(&event->active_entry); 9226 INIT_LIST_HEAD(&event->addr_filters.list); 9227 INIT_HLIST_NODE(&event->hlist_entry); 9228 9229 9230 init_waitqueue_head(&event->waitq); 9231 init_irq_work(&event->pending, perf_pending_event); 9232 9233 mutex_init(&event->mmap_mutex); 9234 raw_spin_lock_init(&event->addr_filters.lock); 9235 9236 atomic_long_set(&event->refcount, 1); 9237 event->cpu = cpu; 9238 event->attr = *attr; 9239 event->group_leader = group_leader; 9240 event->pmu = NULL; 9241 event->oncpu = -1; 9242 9243 event->parent = parent_event; 9244 9245 event->ns = get_pid_ns(task_active_pid_ns(current)); 9246 event->id = atomic64_inc_return(&perf_event_id); 9247 9248 event->state = PERF_EVENT_STATE_INACTIVE; 9249 9250 if (task) { 9251 event->attach_state = PERF_ATTACH_TASK; 9252 /* 9253 * XXX pmu::event_init needs to know what task to account to 9254 * and we cannot use the ctx information because we need the 9255 * pmu before we get a ctx. 9256 */ 9257 event->hw.target = task; 9258 } 9259 9260 event->clock = &local_clock; 9261 if (parent_event) 9262 event->clock = parent_event->clock; 9263 9264 if (!overflow_handler && parent_event) { 9265 overflow_handler = parent_event->overflow_handler; 9266 context = parent_event->overflow_handler_context; 9267 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING) 9268 if (overflow_handler == bpf_overflow_handler) { 9269 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog); 9270 9271 if (IS_ERR(prog)) { 9272 err = PTR_ERR(prog); 9273 goto err_ns; 9274 } 9275 event->prog = prog; 9276 event->orig_overflow_handler = 9277 parent_event->orig_overflow_handler; 9278 } 9279 #endif 9280 } 9281 9282 if (overflow_handler) { 9283 event->overflow_handler = overflow_handler; 9284 event->overflow_handler_context = context; 9285 } else if (is_write_backward(event)){ 9286 event->overflow_handler = perf_event_output_backward; 9287 event->overflow_handler_context = NULL; 9288 } else { 9289 event->overflow_handler = perf_event_output_forward; 9290 event->overflow_handler_context = NULL; 9291 } 9292 9293 perf_event__state_init(event); 9294 9295 pmu = NULL; 9296 9297 hwc = &event->hw; 9298 hwc->sample_period = attr->sample_period; 9299 if (attr->freq && attr->sample_freq) 9300 hwc->sample_period = 1; 9301 hwc->last_period = hwc->sample_period; 9302 9303 local64_set(&hwc->period_left, hwc->sample_period); 9304 9305 /* 9306 * we currently do not support PERF_FORMAT_GROUP on inherited events 9307 */ 9308 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP)) 9309 goto err_ns; 9310 9311 if (!has_branch_stack(event)) 9312 event->attr.branch_sample_type = 0; 9313 9314 if (cgroup_fd != -1) { 9315 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader); 9316 if (err) 9317 goto err_ns; 9318 } 9319 9320 pmu = perf_init_event(event); 9321 if (!pmu) 9322 goto err_ns; 9323 else if (IS_ERR(pmu)) { 9324 err = PTR_ERR(pmu); 9325 goto err_ns; 9326 } 9327 9328 err = exclusive_event_init(event); 9329 if (err) 9330 goto err_pmu; 9331 9332 if (has_addr_filter(event)) { 9333 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters, 9334 sizeof(unsigned long), 9335 GFP_KERNEL); 9336 if (!event->addr_filters_offs) 9337 goto err_per_task; 9338 9339 /* force hw sync on the address filters */ 9340 event->addr_filters_gen = 1; 9341 } 9342 9343 if (!event->parent) { 9344 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) { 9345 err = get_callchain_buffers(attr->sample_max_stack); 9346 if (err) 9347 goto err_addr_filters; 9348 } 9349 } 9350 9351 /* symmetric to unaccount_event() in _free_event() */ 9352 account_event(event); 9353 9354 return event; 9355 9356 err_addr_filters: 9357 kfree(event->addr_filters_offs); 9358 9359 err_per_task: 9360 exclusive_event_destroy(event); 9361 9362 err_pmu: 9363 if (event->destroy) 9364 event->destroy(event); 9365 module_put(pmu->module); 9366 err_ns: 9367 if (is_cgroup_event(event)) 9368 perf_detach_cgroup(event); 9369 if (event->ns) 9370 put_pid_ns(event->ns); 9371 kfree(event); 9372 9373 return ERR_PTR(err); 9374 } 9375 9376 static int perf_copy_attr(struct perf_event_attr __user *uattr, 9377 struct perf_event_attr *attr) 9378 { 9379 u32 size; 9380 int ret; 9381 9382 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0)) 9383 return -EFAULT; 9384 9385 /* 9386 * zero the full structure, so that a short copy will be nice. 9387 */ 9388 memset(attr, 0, sizeof(*attr)); 9389 9390 ret = get_user(size, &uattr->size); 9391 if (ret) 9392 return ret; 9393 9394 if (size > PAGE_SIZE) /* silly large */ 9395 goto err_size; 9396 9397 if (!size) /* abi compat */ 9398 size = PERF_ATTR_SIZE_VER0; 9399 9400 if (size < PERF_ATTR_SIZE_VER0) 9401 goto err_size; 9402 9403 /* 9404 * If we're handed a bigger struct than we know of, 9405 * ensure all the unknown bits are 0 - i.e. new 9406 * user-space does not rely on any kernel feature 9407 * extensions we dont know about yet. 9408 */ 9409 if (size > sizeof(*attr)) { 9410 unsigned char __user *addr; 9411 unsigned char __user *end; 9412 unsigned char val; 9413 9414 addr = (void __user *)uattr + sizeof(*attr); 9415 end = (void __user *)uattr + size; 9416 9417 for (; addr < end; addr++) { 9418 ret = get_user(val, addr); 9419 if (ret) 9420 return ret; 9421 if (val) 9422 goto err_size; 9423 } 9424 size = sizeof(*attr); 9425 } 9426 9427 ret = copy_from_user(attr, uattr, size); 9428 if (ret) 9429 return -EFAULT; 9430 9431 if (attr->__reserved_1) 9432 return -EINVAL; 9433 9434 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1)) 9435 return -EINVAL; 9436 9437 if (attr->read_format & ~(PERF_FORMAT_MAX-1)) 9438 return -EINVAL; 9439 9440 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) { 9441 u64 mask = attr->branch_sample_type; 9442 9443 /* only using defined bits */ 9444 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1)) 9445 return -EINVAL; 9446 9447 /* at least one branch bit must be set */ 9448 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL)) 9449 return -EINVAL; 9450 9451 /* propagate priv level, when not set for branch */ 9452 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) { 9453 9454 /* exclude_kernel checked on syscall entry */ 9455 if (!attr->exclude_kernel) 9456 mask |= PERF_SAMPLE_BRANCH_KERNEL; 9457 9458 if (!attr->exclude_user) 9459 mask |= PERF_SAMPLE_BRANCH_USER; 9460 9461 if (!attr->exclude_hv) 9462 mask |= PERF_SAMPLE_BRANCH_HV; 9463 /* 9464 * adjust user setting (for HW filter setup) 9465 */ 9466 attr->branch_sample_type = mask; 9467 } 9468 /* privileged levels capture (kernel, hv): check permissions */ 9469 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM) 9470 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) 9471 return -EACCES; 9472 } 9473 9474 if (attr->sample_type & PERF_SAMPLE_REGS_USER) { 9475 ret = perf_reg_validate(attr->sample_regs_user); 9476 if (ret) 9477 return ret; 9478 } 9479 9480 if (attr->sample_type & PERF_SAMPLE_STACK_USER) { 9481 if (!arch_perf_have_user_stack_dump()) 9482 return -ENOSYS; 9483 9484 /* 9485 * We have __u32 type for the size, but so far 9486 * we can only use __u16 as maximum due to the 9487 * __u16 sample size limit. 9488 */ 9489 if (attr->sample_stack_user >= USHRT_MAX) 9490 ret = -EINVAL; 9491 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64))) 9492 ret = -EINVAL; 9493 } 9494 9495 if (attr->sample_type & PERF_SAMPLE_REGS_INTR) 9496 ret = perf_reg_validate(attr->sample_regs_intr); 9497 out: 9498 return ret; 9499 9500 err_size: 9501 put_user(sizeof(*attr), &uattr->size); 9502 ret = -E2BIG; 9503 goto out; 9504 } 9505 9506 static int 9507 perf_event_set_output(struct perf_event *event, struct perf_event *output_event) 9508 { 9509 struct ring_buffer *rb = NULL; 9510 int ret = -EINVAL; 9511 9512 if (!output_event) 9513 goto set; 9514 9515 /* don't allow circular references */ 9516 if (event == output_event) 9517 goto out; 9518 9519 /* 9520 * Don't allow cross-cpu buffers 9521 */ 9522 if (output_event->cpu != event->cpu) 9523 goto out; 9524 9525 /* 9526 * If its not a per-cpu rb, it must be the same task. 9527 */ 9528 if (output_event->cpu == -1 && output_event->ctx != event->ctx) 9529 goto out; 9530 9531 /* 9532 * Mixing clocks in the same buffer is trouble you don't need. 9533 */ 9534 if (output_event->clock != event->clock) 9535 goto out; 9536 9537 /* 9538 * Either writing ring buffer from beginning or from end. 9539 * Mixing is not allowed. 9540 */ 9541 if (is_write_backward(output_event) != is_write_backward(event)) 9542 goto out; 9543 9544 /* 9545 * If both events generate aux data, they must be on the same PMU 9546 */ 9547 if (has_aux(event) && has_aux(output_event) && 9548 event->pmu != output_event->pmu) 9549 goto out; 9550 9551 set: 9552 mutex_lock(&event->mmap_mutex); 9553 /* Can't redirect output if we've got an active mmap() */ 9554 if (atomic_read(&event->mmap_count)) 9555 goto unlock; 9556 9557 if (output_event) { 9558 /* get the rb we want to redirect to */ 9559 rb = ring_buffer_get(output_event); 9560 if (!rb) 9561 goto unlock; 9562 } 9563 9564 ring_buffer_attach(event, rb); 9565 9566 ret = 0; 9567 unlock: 9568 mutex_unlock(&event->mmap_mutex); 9569 9570 out: 9571 return ret; 9572 } 9573 9574 static void mutex_lock_double(struct mutex *a, struct mutex *b) 9575 { 9576 if (b < a) 9577 swap(a, b); 9578 9579 mutex_lock(a); 9580 mutex_lock_nested(b, SINGLE_DEPTH_NESTING); 9581 } 9582 9583 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id) 9584 { 9585 bool nmi_safe = false; 9586 9587 switch (clk_id) { 9588 case CLOCK_MONOTONIC: 9589 event->clock = &ktime_get_mono_fast_ns; 9590 nmi_safe = true; 9591 break; 9592 9593 case CLOCK_MONOTONIC_RAW: 9594 event->clock = &ktime_get_raw_fast_ns; 9595 nmi_safe = true; 9596 break; 9597 9598 case CLOCK_REALTIME: 9599 event->clock = &ktime_get_real_ns; 9600 break; 9601 9602 case CLOCK_BOOTTIME: 9603 event->clock = &ktime_get_boot_ns; 9604 break; 9605 9606 case CLOCK_TAI: 9607 event->clock = &ktime_get_tai_ns; 9608 break; 9609 9610 default: 9611 return -EINVAL; 9612 } 9613 9614 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI)) 9615 return -EINVAL; 9616 9617 return 0; 9618 } 9619 9620 /* 9621 * Variation on perf_event_ctx_lock_nested(), except we take two context 9622 * mutexes. 9623 */ 9624 static struct perf_event_context * 9625 __perf_event_ctx_lock_double(struct perf_event *group_leader, 9626 struct perf_event_context *ctx) 9627 { 9628 struct perf_event_context *gctx; 9629 9630 again: 9631 rcu_read_lock(); 9632 gctx = READ_ONCE(group_leader->ctx); 9633 if (!atomic_inc_not_zero(&gctx->refcount)) { 9634 rcu_read_unlock(); 9635 goto again; 9636 } 9637 rcu_read_unlock(); 9638 9639 mutex_lock_double(&gctx->mutex, &ctx->mutex); 9640 9641 if (group_leader->ctx != gctx) { 9642 mutex_unlock(&ctx->mutex); 9643 mutex_unlock(&gctx->mutex); 9644 put_ctx(gctx); 9645 goto again; 9646 } 9647 9648 return gctx; 9649 } 9650 9651 /** 9652 * sys_perf_event_open - open a performance event, associate it to a task/cpu 9653 * 9654 * @attr_uptr: event_id type attributes for monitoring/sampling 9655 * @pid: target pid 9656 * @cpu: target cpu 9657 * @group_fd: group leader event fd 9658 */ 9659 SYSCALL_DEFINE5(perf_event_open, 9660 struct perf_event_attr __user *, attr_uptr, 9661 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags) 9662 { 9663 struct perf_event *group_leader = NULL, *output_event = NULL; 9664 struct perf_event *event, *sibling; 9665 struct perf_event_attr attr; 9666 struct perf_event_context *ctx, *uninitialized_var(gctx); 9667 struct file *event_file = NULL; 9668 struct fd group = {NULL, 0}; 9669 struct task_struct *task = NULL; 9670 struct pmu *pmu; 9671 int event_fd; 9672 int move_group = 0; 9673 int err; 9674 int f_flags = O_RDWR; 9675 int cgroup_fd = -1; 9676 9677 /* for future expandability... */ 9678 if (flags & ~PERF_FLAG_ALL) 9679 return -EINVAL; 9680 9681 err = perf_copy_attr(attr_uptr, &attr); 9682 if (err) 9683 return err; 9684 9685 if (!attr.exclude_kernel) { 9686 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) 9687 return -EACCES; 9688 } 9689 9690 if (attr.freq) { 9691 if (attr.sample_freq > sysctl_perf_event_sample_rate) 9692 return -EINVAL; 9693 } else { 9694 if (attr.sample_period & (1ULL << 63)) 9695 return -EINVAL; 9696 } 9697 9698 if (!attr.sample_max_stack) 9699 attr.sample_max_stack = sysctl_perf_event_max_stack; 9700 9701 /* 9702 * In cgroup mode, the pid argument is used to pass the fd 9703 * opened to the cgroup directory in cgroupfs. The cpu argument 9704 * designates the cpu on which to monitor threads from that 9705 * cgroup. 9706 */ 9707 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1)) 9708 return -EINVAL; 9709 9710 if (flags & PERF_FLAG_FD_CLOEXEC) 9711 f_flags |= O_CLOEXEC; 9712 9713 event_fd = get_unused_fd_flags(f_flags); 9714 if (event_fd < 0) 9715 return event_fd; 9716 9717 if (group_fd != -1) { 9718 err = perf_fget_light(group_fd, &group); 9719 if (err) 9720 goto err_fd; 9721 group_leader = group.file->private_data; 9722 if (flags & PERF_FLAG_FD_OUTPUT) 9723 output_event = group_leader; 9724 if (flags & PERF_FLAG_FD_NO_GROUP) 9725 group_leader = NULL; 9726 } 9727 9728 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) { 9729 task = find_lively_task_by_vpid(pid); 9730 if (IS_ERR(task)) { 9731 err = PTR_ERR(task); 9732 goto err_group_fd; 9733 } 9734 } 9735 9736 if (task && group_leader && 9737 group_leader->attr.inherit != attr.inherit) { 9738 err = -EINVAL; 9739 goto err_task; 9740 } 9741 9742 get_online_cpus(); 9743 9744 if (task) { 9745 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex); 9746 if (err) 9747 goto err_cpus; 9748 9749 /* 9750 * Reuse ptrace permission checks for now. 9751 * 9752 * We must hold cred_guard_mutex across this and any potential 9753 * perf_install_in_context() call for this new event to 9754 * serialize against exec() altering our credentials (and the 9755 * perf_event_exit_task() that could imply). 9756 */ 9757 err = -EACCES; 9758 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) 9759 goto err_cred; 9760 } 9761 9762 if (flags & PERF_FLAG_PID_CGROUP) 9763 cgroup_fd = pid; 9764 9765 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, 9766 NULL, NULL, cgroup_fd); 9767 if (IS_ERR(event)) { 9768 err = PTR_ERR(event); 9769 goto err_cred; 9770 } 9771 9772 if (is_sampling_event(event)) { 9773 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) { 9774 err = -EOPNOTSUPP; 9775 goto err_alloc; 9776 } 9777 } 9778 9779 /* 9780 * Special case software events and allow them to be part of 9781 * any hardware group. 9782 */ 9783 pmu = event->pmu; 9784 9785 if (attr.use_clockid) { 9786 err = perf_event_set_clock(event, attr.clockid); 9787 if (err) 9788 goto err_alloc; 9789 } 9790 9791 if (pmu->task_ctx_nr == perf_sw_context) 9792 event->event_caps |= PERF_EV_CAP_SOFTWARE; 9793 9794 if (group_leader && 9795 (is_software_event(event) != is_software_event(group_leader))) { 9796 if (is_software_event(event)) { 9797 /* 9798 * If event and group_leader are not both a software 9799 * event, and event is, then group leader is not. 9800 * 9801 * Allow the addition of software events to !software 9802 * groups, this is safe because software events never 9803 * fail to schedule. 9804 */ 9805 pmu = group_leader->pmu; 9806 } else if (is_software_event(group_leader) && 9807 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) { 9808 /* 9809 * In case the group is a pure software group, and we 9810 * try to add a hardware event, move the whole group to 9811 * the hardware context. 9812 */ 9813 move_group = 1; 9814 } 9815 } 9816 9817 /* 9818 * Get the target context (task or percpu): 9819 */ 9820 ctx = find_get_context(pmu, task, event); 9821 if (IS_ERR(ctx)) { 9822 err = PTR_ERR(ctx); 9823 goto err_alloc; 9824 } 9825 9826 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) { 9827 err = -EBUSY; 9828 goto err_context; 9829 } 9830 9831 /* 9832 * Look up the group leader (we will attach this event to it): 9833 */ 9834 if (group_leader) { 9835 err = -EINVAL; 9836 9837 /* 9838 * Do not allow a recursive hierarchy (this new sibling 9839 * becoming part of another group-sibling): 9840 */ 9841 if (group_leader->group_leader != group_leader) 9842 goto err_context; 9843 9844 /* All events in a group should have the same clock */ 9845 if (group_leader->clock != event->clock) 9846 goto err_context; 9847 9848 /* 9849 * Do not allow to attach to a group in a different 9850 * task or CPU context: 9851 */ 9852 if (move_group) { 9853 /* 9854 * Make sure we're both on the same task, or both 9855 * per-cpu events. 9856 */ 9857 if (group_leader->ctx->task != ctx->task) 9858 goto err_context; 9859 9860 /* 9861 * Make sure we're both events for the same CPU; 9862 * grouping events for different CPUs is broken; since 9863 * you can never concurrently schedule them anyhow. 9864 */ 9865 if (group_leader->cpu != event->cpu) 9866 goto err_context; 9867 } else { 9868 if (group_leader->ctx != ctx) 9869 goto err_context; 9870 } 9871 9872 /* 9873 * Only a group leader can be exclusive or pinned 9874 */ 9875 if (attr.exclusive || attr.pinned) 9876 goto err_context; 9877 } 9878 9879 if (output_event) { 9880 err = perf_event_set_output(event, output_event); 9881 if (err) 9882 goto err_context; 9883 } 9884 9885 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, 9886 f_flags); 9887 if (IS_ERR(event_file)) { 9888 err = PTR_ERR(event_file); 9889 event_file = NULL; 9890 goto err_context; 9891 } 9892 9893 if (move_group) { 9894 gctx = __perf_event_ctx_lock_double(group_leader, ctx); 9895 9896 if (gctx->task == TASK_TOMBSTONE) { 9897 err = -ESRCH; 9898 goto err_locked; 9899 } 9900 9901 /* 9902 * Check if we raced against another sys_perf_event_open() call 9903 * moving the software group underneath us. 9904 */ 9905 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) { 9906 /* 9907 * If someone moved the group out from under us, check 9908 * if this new event wound up on the same ctx, if so 9909 * its the regular !move_group case, otherwise fail. 9910 */ 9911 if (gctx != ctx) { 9912 err = -EINVAL; 9913 goto err_locked; 9914 } else { 9915 perf_event_ctx_unlock(group_leader, gctx); 9916 move_group = 0; 9917 } 9918 } 9919 } else { 9920 mutex_lock(&ctx->mutex); 9921 } 9922 9923 if (ctx->task == TASK_TOMBSTONE) { 9924 err = -ESRCH; 9925 goto err_locked; 9926 } 9927 9928 if (!perf_event_validate_size(event)) { 9929 err = -E2BIG; 9930 goto err_locked; 9931 } 9932 9933 /* 9934 * Must be under the same ctx::mutex as perf_install_in_context(), 9935 * because we need to serialize with concurrent event creation. 9936 */ 9937 if (!exclusive_event_installable(event, ctx)) { 9938 /* exclusive and group stuff are assumed mutually exclusive */ 9939 WARN_ON_ONCE(move_group); 9940 9941 err = -EBUSY; 9942 goto err_locked; 9943 } 9944 9945 WARN_ON_ONCE(ctx->parent_ctx); 9946 9947 /* 9948 * This is the point on no return; we cannot fail hereafter. This is 9949 * where we start modifying current state. 9950 */ 9951 9952 if (move_group) { 9953 /* 9954 * See perf_event_ctx_lock() for comments on the details 9955 * of swizzling perf_event::ctx. 9956 */ 9957 perf_remove_from_context(group_leader, 0); 9958 9959 list_for_each_entry(sibling, &group_leader->sibling_list, 9960 group_entry) { 9961 perf_remove_from_context(sibling, 0); 9962 put_ctx(gctx); 9963 } 9964 9965 /* 9966 * Wait for everybody to stop referencing the events through 9967 * the old lists, before installing it on new lists. 9968 */ 9969 synchronize_rcu(); 9970 9971 /* 9972 * Install the group siblings before the group leader. 9973 * 9974 * Because a group leader will try and install the entire group 9975 * (through the sibling list, which is still in-tact), we can 9976 * end up with siblings installed in the wrong context. 9977 * 9978 * By installing siblings first we NO-OP because they're not 9979 * reachable through the group lists. 9980 */ 9981 list_for_each_entry(sibling, &group_leader->sibling_list, 9982 group_entry) { 9983 perf_event__state_init(sibling); 9984 perf_install_in_context(ctx, sibling, sibling->cpu); 9985 get_ctx(ctx); 9986 } 9987 9988 /* 9989 * Removing from the context ends up with disabled 9990 * event. What we want here is event in the initial 9991 * startup state, ready to be add into new context. 9992 */ 9993 perf_event__state_init(group_leader); 9994 perf_install_in_context(ctx, group_leader, group_leader->cpu); 9995 get_ctx(ctx); 9996 9997 /* 9998 * Now that all events are installed in @ctx, nothing 9999 * references @gctx anymore, so drop the last reference we have 10000 * on it. 10001 */ 10002 put_ctx(gctx); 10003 } 10004 10005 /* 10006 * Precalculate sample_data sizes; do while holding ctx::mutex such 10007 * that we're serialized against further additions and before 10008 * perf_install_in_context() which is the point the event is active and 10009 * can use these values. 10010 */ 10011 perf_event__header_size(event); 10012 perf_event__id_header_size(event); 10013 10014 event->owner = current; 10015 10016 perf_install_in_context(ctx, event, event->cpu); 10017 perf_unpin_context(ctx); 10018 10019 if (move_group) 10020 perf_event_ctx_unlock(group_leader, gctx); 10021 mutex_unlock(&ctx->mutex); 10022 10023 if (task) { 10024 mutex_unlock(&task->signal->cred_guard_mutex); 10025 put_task_struct(task); 10026 } 10027 10028 put_online_cpus(); 10029 10030 mutex_lock(¤t->perf_event_mutex); 10031 list_add_tail(&event->owner_entry, ¤t->perf_event_list); 10032 mutex_unlock(¤t->perf_event_mutex); 10033 10034 /* 10035 * Drop the reference on the group_event after placing the 10036 * new event on the sibling_list. This ensures destruction 10037 * of the group leader will find the pointer to itself in 10038 * perf_group_detach(). 10039 */ 10040 fdput(group); 10041 fd_install(event_fd, event_file); 10042 return event_fd; 10043 10044 err_locked: 10045 if (move_group) 10046 perf_event_ctx_unlock(group_leader, gctx); 10047 mutex_unlock(&ctx->mutex); 10048 /* err_file: */ 10049 fput(event_file); 10050 err_context: 10051 perf_unpin_context(ctx); 10052 put_ctx(ctx); 10053 err_alloc: 10054 /* 10055 * If event_file is set, the fput() above will have called ->release() 10056 * and that will take care of freeing the event. 10057 */ 10058 if (!event_file) 10059 free_event(event); 10060 err_cred: 10061 if (task) 10062 mutex_unlock(&task->signal->cred_guard_mutex); 10063 err_cpus: 10064 put_online_cpus(); 10065 err_task: 10066 if (task) 10067 put_task_struct(task); 10068 err_group_fd: 10069 fdput(group); 10070 err_fd: 10071 put_unused_fd(event_fd); 10072 return err; 10073 } 10074 10075 /** 10076 * perf_event_create_kernel_counter 10077 * 10078 * @attr: attributes of the counter to create 10079 * @cpu: cpu in which the counter is bound 10080 * @task: task to profile (NULL for percpu) 10081 */ 10082 struct perf_event * 10083 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, 10084 struct task_struct *task, 10085 perf_overflow_handler_t overflow_handler, 10086 void *context) 10087 { 10088 struct perf_event_context *ctx; 10089 struct perf_event *event; 10090 int err; 10091 10092 /* 10093 * Get the target context (task or percpu): 10094 */ 10095 10096 event = perf_event_alloc(attr, cpu, task, NULL, NULL, 10097 overflow_handler, context, -1); 10098 if (IS_ERR(event)) { 10099 err = PTR_ERR(event); 10100 goto err; 10101 } 10102 10103 /* Mark owner so we could distinguish it from user events. */ 10104 event->owner = TASK_TOMBSTONE; 10105 10106 ctx = find_get_context(event->pmu, task, event); 10107 if (IS_ERR(ctx)) { 10108 err = PTR_ERR(ctx); 10109 goto err_free; 10110 } 10111 10112 WARN_ON_ONCE(ctx->parent_ctx); 10113 mutex_lock(&ctx->mutex); 10114 if (ctx->task == TASK_TOMBSTONE) { 10115 err = -ESRCH; 10116 goto err_unlock; 10117 } 10118 10119 if (!exclusive_event_installable(event, ctx)) { 10120 err = -EBUSY; 10121 goto err_unlock; 10122 } 10123 10124 perf_install_in_context(ctx, event, cpu); 10125 perf_unpin_context(ctx); 10126 mutex_unlock(&ctx->mutex); 10127 10128 return event; 10129 10130 err_unlock: 10131 mutex_unlock(&ctx->mutex); 10132 perf_unpin_context(ctx); 10133 put_ctx(ctx); 10134 err_free: 10135 free_event(event); 10136 err: 10137 return ERR_PTR(err); 10138 } 10139 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter); 10140 10141 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu) 10142 { 10143 struct perf_event_context *src_ctx; 10144 struct perf_event_context *dst_ctx; 10145 struct perf_event *event, *tmp; 10146 LIST_HEAD(events); 10147 10148 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx; 10149 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx; 10150 10151 /* 10152 * See perf_event_ctx_lock() for comments on the details 10153 * of swizzling perf_event::ctx. 10154 */ 10155 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex); 10156 list_for_each_entry_safe(event, tmp, &src_ctx->event_list, 10157 event_entry) { 10158 perf_remove_from_context(event, 0); 10159 unaccount_event_cpu(event, src_cpu); 10160 put_ctx(src_ctx); 10161 list_add(&event->migrate_entry, &events); 10162 } 10163 10164 /* 10165 * Wait for the events to quiesce before re-instating them. 10166 */ 10167 synchronize_rcu(); 10168 10169 /* 10170 * Re-instate events in 2 passes. 10171 * 10172 * Skip over group leaders and only install siblings on this first 10173 * pass, siblings will not get enabled without a leader, however a 10174 * leader will enable its siblings, even if those are still on the old 10175 * context. 10176 */ 10177 list_for_each_entry_safe(event, tmp, &events, migrate_entry) { 10178 if (event->group_leader == event) 10179 continue; 10180 10181 list_del(&event->migrate_entry); 10182 if (event->state >= PERF_EVENT_STATE_OFF) 10183 event->state = PERF_EVENT_STATE_INACTIVE; 10184 account_event_cpu(event, dst_cpu); 10185 perf_install_in_context(dst_ctx, event, dst_cpu); 10186 get_ctx(dst_ctx); 10187 } 10188 10189 /* 10190 * Once all the siblings are setup properly, install the group leaders 10191 * to make it go. 10192 */ 10193 list_for_each_entry_safe(event, tmp, &events, migrate_entry) { 10194 list_del(&event->migrate_entry); 10195 if (event->state >= PERF_EVENT_STATE_OFF) 10196 event->state = PERF_EVENT_STATE_INACTIVE; 10197 account_event_cpu(event, dst_cpu); 10198 perf_install_in_context(dst_ctx, event, dst_cpu); 10199 get_ctx(dst_ctx); 10200 } 10201 mutex_unlock(&dst_ctx->mutex); 10202 mutex_unlock(&src_ctx->mutex); 10203 } 10204 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context); 10205 10206 static void sync_child_event(struct perf_event *child_event, 10207 struct task_struct *child) 10208 { 10209 struct perf_event *parent_event = child_event->parent; 10210 u64 child_val; 10211 10212 if (child_event->attr.inherit_stat) 10213 perf_event_read_event(child_event, child); 10214 10215 child_val = perf_event_count(child_event); 10216 10217 /* 10218 * Add back the child's count to the parent's count: 10219 */ 10220 atomic64_add(child_val, &parent_event->child_count); 10221 atomic64_add(child_event->total_time_enabled, 10222 &parent_event->child_total_time_enabled); 10223 atomic64_add(child_event->total_time_running, 10224 &parent_event->child_total_time_running); 10225 } 10226 10227 static void 10228 perf_event_exit_event(struct perf_event *child_event, 10229 struct perf_event_context *child_ctx, 10230 struct task_struct *child) 10231 { 10232 struct perf_event *parent_event = child_event->parent; 10233 10234 /* 10235 * Do not destroy the 'original' grouping; because of the context 10236 * switch optimization the original events could've ended up in a 10237 * random child task. 10238 * 10239 * If we were to destroy the original group, all group related 10240 * operations would cease to function properly after this random 10241 * child dies. 10242 * 10243 * Do destroy all inherited groups, we don't care about those 10244 * and being thorough is better. 10245 */ 10246 raw_spin_lock_irq(&child_ctx->lock); 10247 WARN_ON_ONCE(child_ctx->is_active); 10248 10249 if (parent_event) 10250 perf_group_detach(child_event); 10251 list_del_event(child_event, child_ctx); 10252 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */ 10253 raw_spin_unlock_irq(&child_ctx->lock); 10254 10255 /* 10256 * Parent events are governed by their filedesc, retain them. 10257 */ 10258 if (!parent_event) { 10259 perf_event_wakeup(child_event); 10260 return; 10261 } 10262 /* 10263 * Child events can be cleaned up. 10264 */ 10265 10266 sync_child_event(child_event, child); 10267 10268 /* 10269 * Remove this event from the parent's list 10270 */ 10271 WARN_ON_ONCE(parent_event->ctx->parent_ctx); 10272 mutex_lock(&parent_event->child_mutex); 10273 list_del_init(&child_event->child_list); 10274 mutex_unlock(&parent_event->child_mutex); 10275 10276 /* 10277 * Kick perf_poll() for is_event_hup(). 10278 */ 10279 perf_event_wakeup(parent_event); 10280 free_event(child_event); 10281 put_event(parent_event); 10282 } 10283 10284 static void perf_event_exit_task_context(struct task_struct *child, int ctxn) 10285 { 10286 struct perf_event_context *child_ctx, *clone_ctx = NULL; 10287 struct perf_event *child_event, *next; 10288 10289 WARN_ON_ONCE(child != current); 10290 10291 child_ctx = perf_pin_task_context(child, ctxn); 10292 if (!child_ctx) 10293 return; 10294 10295 /* 10296 * In order to reduce the amount of tricky in ctx tear-down, we hold 10297 * ctx::mutex over the entire thing. This serializes against almost 10298 * everything that wants to access the ctx. 10299 * 10300 * The exception is sys_perf_event_open() / 10301 * perf_event_create_kernel_count() which does find_get_context() 10302 * without ctx::mutex (it cannot because of the move_group double mutex 10303 * lock thing). See the comments in perf_install_in_context(). 10304 */ 10305 mutex_lock(&child_ctx->mutex); 10306 10307 /* 10308 * In a single ctx::lock section, de-schedule the events and detach the 10309 * context from the task such that we cannot ever get it scheduled back 10310 * in. 10311 */ 10312 raw_spin_lock_irq(&child_ctx->lock); 10313 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL); 10314 10315 /* 10316 * Now that the context is inactive, destroy the task <-> ctx relation 10317 * and mark the context dead. 10318 */ 10319 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL); 10320 put_ctx(child_ctx); /* cannot be last */ 10321 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE); 10322 put_task_struct(current); /* cannot be last */ 10323 10324 clone_ctx = unclone_ctx(child_ctx); 10325 raw_spin_unlock_irq(&child_ctx->lock); 10326 10327 if (clone_ctx) 10328 put_ctx(clone_ctx); 10329 10330 /* 10331 * Report the task dead after unscheduling the events so that we 10332 * won't get any samples after PERF_RECORD_EXIT. We can however still 10333 * get a few PERF_RECORD_READ events. 10334 */ 10335 perf_event_task(child, child_ctx, 0); 10336 10337 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry) 10338 perf_event_exit_event(child_event, child_ctx, child); 10339 10340 mutex_unlock(&child_ctx->mutex); 10341 10342 put_ctx(child_ctx); 10343 } 10344 10345 /* 10346 * When a child task exits, feed back event values to parent events. 10347 * 10348 * Can be called with cred_guard_mutex held when called from 10349 * install_exec_creds(). 10350 */ 10351 void perf_event_exit_task(struct task_struct *child) 10352 { 10353 struct perf_event *event, *tmp; 10354 int ctxn; 10355 10356 mutex_lock(&child->perf_event_mutex); 10357 list_for_each_entry_safe(event, tmp, &child->perf_event_list, 10358 owner_entry) { 10359 list_del_init(&event->owner_entry); 10360 10361 /* 10362 * Ensure the list deletion is visible before we clear 10363 * the owner, closes a race against perf_release() where 10364 * we need to serialize on the owner->perf_event_mutex. 10365 */ 10366 smp_store_release(&event->owner, NULL); 10367 } 10368 mutex_unlock(&child->perf_event_mutex); 10369 10370 for_each_task_context_nr(ctxn) 10371 perf_event_exit_task_context(child, ctxn); 10372 10373 /* 10374 * The perf_event_exit_task_context calls perf_event_task 10375 * with child's task_ctx, which generates EXIT events for 10376 * child contexts and sets child->perf_event_ctxp[] to NULL. 10377 * At this point we need to send EXIT events to cpu contexts. 10378 */ 10379 perf_event_task(child, NULL, 0); 10380 } 10381 10382 static void perf_free_event(struct perf_event *event, 10383 struct perf_event_context *ctx) 10384 { 10385 struct perf_event *parent = event->parent; 10386 10387 if (WARN_ON_ONCE(!parent)) 10388 return; 10389 10390 mutex_lock(&parent->child_mutex); 10391 list_del_init(&event->child_list); 10392 mutex_unlock(&parent->child_mutex); 10393 10394 put_event(parent); 10395 10396 raw_spin_lock_irq(&ctx->lock); 10397 perf_group_detach(event); 10398 list_del_event(event, ctx); 10399 raw_spin_unlock_irq(&ctx->lock); 10400 free_event(event); 10401 } 10402 10403 /* 10404 * Free an unexposed, unused context as created by inheritance by 10405 * perf_event_init_task below, used by fork() in case of fail. 10406 * 10407 * Not all locks are strictly required, but take them anyway to be nice and 10408 * help out with the lockdep assertions. 10409 */ 10410 void perf_event_free_task(struct task_struct *task) 10411 { 10412 struct perf_event_context *ctx; 10413 struct perf_event *event, *tmp; 10414 int ctxn; 10415 10416 for_each_task_context_nr(ctxn) { 10417 ctx = task->perf_event_ctxp[ctxn]; 10418 if (!ctx) 10419 continue; 10420 10421 mutex_lock(&ctx->mutex); 10422 again: 10423 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, 10424 group_entry) 10425 perf_free_event(event, ctx); 10426 10427 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, 10428 group_entry) 10429 perf_free_event(event, ctx); 10430 10431 if (!list_empty(&ctx->pinned_groups) || 10432 !list_empty(&ctx->flexible_groups)) 10433 goto again; 10434 10435 mutex_unlock(&ctx->mutex); 10436 10437 put_ctx(ctx); 10438 } 10439 } 10440 10441 void perf_event_delayed_put(struct task_struct *task) 10442 { 10443 int ctxn; 10444 10445 for_each_task_context_nr(ctxn) 10446 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]); 10447 } 10448 10449 struct file *perf_event_get(unsigned int fd) 10450 { 10451 struct file *file; 10452 10453 file = fget_raw(fd); 10454 if (!file) 10455 return ERR_PTR(-EBADF); 10456 10457 if (file->f_op != &perf_fops) { 10458 fput(file); 10459 return ERR_PTR(-EBADF); 10460 } 10461 10462 return file; 10463 } 10464 10465 const struct perf_event_attr *perf_event_attrs(struct perf_event *event) 10466 { 10467 if (!event) 10468 return ERR_PTR(-EINVAL); 10469 10470 return &event->attr; 10471 } 10472 10473 /* 10474 * inherit a event from parent task to child task: 10475 */ 10476 static struct perf_event * 10477 inherit_event(struct perf_event *parent_event, 10478 struct task_struct *parent, 10479 struct perf_event_context *parent_ctx, 10480 struct task_struct *child, 10481 struct perf_event *group_leader, 10482 struct perf_event_context *child_ctx) 10483 { 10484 enum perf_event_active_state parent_state = parent_event->state; 10485 struct perf_event *child_event; 10486 unsigned long flags; 10487 10488 /* 10489 * Instead of creating recursive hierarchies of events, 10490 * we link inherited events back to the original parent, 10491 * which has a filp for sure, which we use as the reference 10492 * count: 10493 */ 10494 if (parent_event->parent) 10495 parent_event = parent_event->parent; 10496 10497 child_event = perf_event_alloc(&parent_event->attr, 10498 parent_event->cpu, 10499 child, 10500 group_leader, parent_event, 10501 NULL, NULL, -1); 10502 if (IS_ERR(child_event)) 10503 return child_event; 10504 10505 /* 10506 * is_orphaned_event() and list_add_tail(&parent_event->child_list) 10507 * must be under the same lock in order to serialize against 10508 * perf_event_release_kernel(), such that either we must observe 10509 * is_orphaned_event() or they will observe us on the child_list. 10510 */ 10511 mutex_lock(&parent_event->child_mutex); 10512 if (is_orphaned_event(parent_event) || 10513 !atomic_long_inc_not_zero(&parent_event->refcount)) { 10514 mutex_unlock(&parent_event->child_mutex); 10515 free_event(child_event); 10516 return NULL; 10517 } 10518 10519 get_ctx(child_ctx); 10520 10521 /* 10522 * Make the child state follow the state of the parent event, 10523 * not its attr.disabled bit. We hold the parent's mutex, 10524 * so we won't race with perf_event_{en, dis}able_family. 10525 */ 10526 if (parent_state >= PERF_EVENT_STATE_INACTIVE) 10527 child_event->state = PERF_EVENT_STATE_INACTIVE; 10528 else 10529 child_event->state = PERF_EVENT_STATE_OFF; 10530 10531 if (parent_event->attr.freq) { 10532 u64 sample_period = parent_event->hw.sample_period; 10533 struct hw_perf_event *hwc = &child_event->hw; 10534 10535 hwc->sample_period = sample_period; 10536 hwc->last_period = sample_period; 10537 10538 local64_set(&hwc->period_left, sample_period); 10539 } 10540 10541 child_event->ctx = child_ctx; 10542 child_event->overflow_handler = parent_event->overflow_handler; 10543 child_event->overflow_handler_context 10544 = parent_event->overflow_handler_context; 10545 10546 /* 10547 * Precalculate sample_data sizes 10548 */ 10549 perf_event__header_size(child_event); 10550 perf_event__id_header_size(child_event); 10551 10552 /* 10553 * Link it up in the child's context: 10554 */ 10555 raw_spin_lock_irqsave(&child_ctx->lock, flags); 10556 add_event_to_ctx(child_event, child_ctx); 10557 raw_spin_unlock_irqrestore(&child_ctx->lock, flags); 10558 10559 /* 10560 * Link this into the parent event's child list 10561 */ 10562 list_add_tail(&child_event->child_list, &parent_event->child_list); 10563 mutex_unlock(&parent_event->child_mutex); 10564 10565 return child_event; 10566 } 10567 10568 static int inherit_group(struct perf_event *parent_event, 10569 struct task_struct *parent, 10570 struct perf_event_context *parent_ctx, 10571 struct task_struct *child, 10572 struct perf_event_context *child_ctx) 10573 { 10574 struct perf_event *leader; 10575 struct perf_event *sub; 10576 struct perf_event *child_ctr; 10577 10578 leader = inherit_event(parent_event, parent, parent_ctx, 10579 child, NULL, child_ctx); 10580 if (IS_ERR(leader)) 10581 return PTR_ERR(leader); 10582 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) { 10583 child_ctr = inherit_event(sub, parent, parent_ctx, 10584 child, leader, child_ctx); 10585 if (IS_ERR(child_ctr)) 10586 return PTR_ERR(child_ctr); 10587 } 10588 return 0; 10589 } 10590 10591 static int 10592 inherit_task_group(struct perf_event *event, struct task_struct *parent, 10593 struct perf_event_context *parent_ctx, 10594 struct task_struct *child, int ctxn, 10595 int *inherited_all) 10596 { 10597 int ret; 10598 struct perf_event_context *child_ctx; 10599 10600 if (!event->attr.inherit) { 10601 *inherited_all = 0; 10602 return 0; 10603 } 10604 10605 child_ctx = child->perf_event_ctxp[ctxn]; 10606 if (!child_ctx) { 10607 /* 10608 * This is executed from the parent task context, so 10609 * inherit events that have been marked for cloning. 10610 * First allocate and initialize a context for the 10611 * child. 10612 */ 10613 10614 child_ctx = alloc_perf_context(parent_ctx->pmu, child); 10615 if (!child_ctx) 10616 return -ENOMEM; 10617 10618 child->perf_event_ctxp[ctxn] = child_ctx; 10619 } 10620 10621 ret = inherit_group(event, parent, parent_ctx, 10622 child, child_ctx); 10623 10624 if (ret) 10625 *inherited_all = 0; 10626 10627 return ret; 10628 } 10629 10630 /* 10631 * Initialize the perf_event context in task_struct 10632 */ 10633 static int perf_event_init_context(struct task_struct *child, int ctxn) 10634 { 10635 struct perf_event_context *child_ctx, *parent_ctx; 10636 struct perf_event_context *cloned_ctx; 10637 struct perf_event *event; 10638 struct task_struct *parent = current; 10639 int inherited_all = 1; 10640 unsigned long flags; 10641 int ret = 0; 10642 10643 if (likely(!parent->perf_event_ctxp[ctxn])) 10644 return 0; 10645 10646 /* 10647 * If the parent's context is a clone, pin it so it won't get 10648 * swapped under us. 10649 */ 10650 parent_ctx = perf_pin_task_context(parent, ctxn); 10651 if (!parent_ctx) 10652 return 0; 10653 10654 /* 10655 * No need to check if parent_ctx != NULL here; since we saw 10656 * it non-NULL earlier, the only reason for it to become NULL 10657 * is if we exit, and since we're currently in the middle of 10658 * a fork we can't be exiting at the same time. 10659 */ 10660 10661 /* 10662 * Lock the parent list. No need to lock the child - not PID 10663 * hashed yet and not running, so nobody can access it. 10664 */ 10665 mutex_lock(&parent_ctx->mutex); 10666 10667 /* 10668 * We dont have to disable NMIs - we are only looking at 10669 * the list, not manipulating it: 10670 */ 10671 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) { 10672 ret = inherit_task_group(event, parent, parent_ctx, 10673 child, ctxn, &inherited_all); 10674 if (ret) 10675 break; 10676 } 10677 10678 /* 10679 * We can't hold ctx->lock when iterating the ->flexible_group list due 10680 * to allocations, but we need to prevent rotation because 10681 * rotate_ctx() will change the list from interrupt context. 10682 */ 10683 raw_spin_lock_irqsave(&parent_ctx->lock, flags); 10684 parent_ctx->rotate_disable = 1; 10685 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); 10686 10687 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) { 10688 ret = inherit_task_group(event, parent, parent_ctx, 10689 child, ctxn, &inherited_all); 10690 if (ret) 10691 break; 10692 } 10693 10694 raw_spin_lock_irqsave(&parent_ctx->lock, flags); 10695 parent_ctx->rotate_disable = 0; 10696 10697 child_ctx = child->perf_event_ctxp[ctxn]; 10698 10699 if (child_ctx && inherited_all) { 10700 /* 10701 * Mark the child context as a clone of the parent 10702 * context, or of whatever the parent is a clone of. 10703 * 10704 * Note that if the parent is a clone, the holding of 10705 * parent_ctx->lock avoids it from being uncloned. 10706 */ 10707 cloned_ctx = parent_ctx->parent_ctx; 10708 if (cloned_ctx) { 10709 child_ctx->parent_ctx = cloned_ctx; 10710 child_ctx->parent_gen = parent_ctx->parent_gen; 10711 } else { 10712 child_ctx->parent_ctx = parent_ctx; 10713 child_ctx->parent_gen = parent_ctx->generation; 10714 } 10715 get_ctx(child_ctx->parent_ctx); 10716 } 10717 10718 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); 10719 mutex_unlock(&parent_ctx->mutex); 10720 10721 perf_unpin_context(parent_ctx); 10722 put_ctx(parent_ctx); 10723 10724 return ret; 10725 } 10726 10727 /* 10728 * Initialize the perf_event context in task_struct 10729 */ 10730 int perf_event_init_task(struct task_struct *child) 10731 { 10732 int ctxn, ret; 10733 10734 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp)); 10735 mutex_init(&child->perf_event_mutex); 10736 INIT_LIST_HEAD(&child->perf_event_list); 10737 10738 for_each_task_context_nr(ctxn) { 10739 ret = perf_event_init_context(child, ctxn); 10740 if (ret) { 10741 perf_event_free_task(child); 10742 return ret; 10743 } 10744 } 10745 10746 return 0; 10747 } 10748 10749 static void __init perf_event_init_all_cpus(void) 10750 { 10751 struct swevent_htable *swhash; 10752 int cpu; 10753 10754 for_each_possible_cpu(cpu) { 10755 swhash = &per_cpu(swevent_htable, cpu); 10756 mutex_init(&swhash->hlist_mutex); 10757 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu)); 10758 10759 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu)); 10760 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu)); 10761 10762 #ifdef CONFIG_CGROUP_PERF 10763 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu)); 10764 #endif 10765 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu)); 10766 } 10767 } 10768 10769 int perf_event_init_cpu(unsigned int cpu) 10770 { 10771 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 10772 10773 mutex_lock(&swhash->hlist_mutex); 10774 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) { 10775 struct swevent_hlist *hlist; 10776 10777 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu)); 10778 WARN_ON(!hlist); 10779 rcu_assign_pointer(swhash->swevent_hlist, hlist); 10780 } 10781 mutex_unlock(&swhash->hlist_mutex); 10782 return 0; 10783 } 10784 10785 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE 10786 static void __perf_event_exit_context(void *__info) 10787 { 10788 struct perf_event_context *ctx = __info; 10789 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 10790 struct perf_event *event; 10791 10792 raw_spin_lock(&ctx->lock); 10793 list_for_each_entry(event, &ctx->event_list, event_entry) 10794 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP); 10795 raw_spin_unlock(&ctx->lock); 10796 } 10797 10798 static void perf_event_exit_cpu_context(int cpu) 10799 { 10800 struct perf_event_context *ctx; 10801 struct pmu *pmu; 10802 int idx; 10803 10804 idx = srcu_read_lock(&pmus_srcu); 10805 list_for_each_entry_rcu(pmu, &pmus, entry) { 10806 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx; 10807 10808 mutex_lock(&ctx->mutex); 10809 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1); 10810 mutex_unlock(&ctx->mutex); 10811 } 10812 srcu_read_unlock(&pmus_srcu, idx); 10813 } 10814 #else 10815 10816 static void perf_event_exit_cpu_context(int cpu) { } 10817 10818 #endif 10819 10820 int perf_event_exit_cpu(unsigned int cpu) 10821 { 10822 perf_event_exit_cpu_context(cpu); 10823 return 0; 10824 } 10825 10826 static int 10827 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v) 10828 { 10829 int cpu; 10830 10831 for_each_online_cpu(cpu) 10832 perf_event_exit_cpu(cpu); 10833 10834 return NOTIFY_OK; 10835 } 10836 10837 /* 10838 * Run the perf reboot notifier at the very last possible moment so that 10839 * the generic watchdog code runs as long as possible. 10840 */ 10841 static struct notifier_block perf_reboot_notifier = { 10842 .notifier_call = perf_reboot, 10843 .priority = INT_MIN, 10844 }; 10845 10846 void __init perf_event_init(void) 10847 { 10848 int ret; 10849 10850 idr_init(&pmu_idr); 10851 10852 perf_event_init_all_cpus(); 10853 init_srcu_struct(&pmus_srcu); 10854 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE); 10855 perf_pmu_register(&perf_cpu_clock, NULL, -1); 10856 perf_pmu_register(&perf_task_clock, NULL, -1); 10857 perf_tp_register(); 10858 perf_event_init_cpu(smp_processor_id()); 10859 register_reboot_notifier(&perf_reboot_notifier); 10860 10861 ret = init_hw_breakpoint(); 10862 WARN(ret, "hw_breakpoint initialization failed with: %d", ret); 10863 10864 /* 10865 * Build time assertion that we keep the data_head at the intended 10866 * location. IOW, validation we got the __reserved[] size right. 10867 */ 10868 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head)) 10869 != 1024); 10870 } 10871 10872 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr, 10873 char *page) 10874 { 10875 struct perf_pmu_events_attr *pmu_attr = 10876 container_of(attr, struct perf_pmu_events_attr, attr); 10877 10878 if (pmu_attr->event_str) 10879 return sprintf(page, "%s\n", pmu_attr->event_str); 10880 10881 return 0; 10882 } 10883 EXPORT_SYMBOL_GPL(perf_event_sysfs_show); 10884 10885 static int __init perf_event_sysfs_init(void) 10886 { 10887 struct pmu *pmu; 10888 int ret; 10889 10890 mutex_lock(&pmus_lock); 10891 10892 ret = bus_register(&pmu_bus); 10893 if (ret) 10894 goto unlock; 10895 10896 list_for_each_entry(pmu, &pmus, entry) { 10897 if (!pmu->name || pmu->type < 0) 10898 continue; 10899 10900 ret = pmu_dev_alloc(pmu); 10901 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret); 10902 } 10903 pmu_bus_running = 1; 10904 ret = 0; 10905 10906 unlock: 10907 mutex_unlock(&pmus_lock); 10908 10909 return ret; 10910 } 10911 device_initcall(perf_event_sysfs_init); 10912 10913 #ifdef CONFIG_CGROUP_PERF 10914 static struct cgroup_subsys_state * 10915 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) 10916 { 10917 struct perf_cgroup *jc; 10918 10919 jc = kzalloc(sizeof(*jc), GFP_KERNEL); 10920 if (!jc) 10921 return ERR_PTR(-ENOMEM); 10922 10923 jc->info = alloc_percpu(struct perf_cgroup_info); 10924 if (!jc->info) { 10925 kfree(jc); 10926 return ERR_PTR(-ENOMEM); 10927 } 10928 10929 return &jc->css; 10930 } 10931 10932 static void perf_cgroup_css_free(struct cgroup_subsys_state *css) 10933 { 10934 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css); 10935 10936 free_percpu(jc->info); 10937 kfree(jc); 10938 } 10939 10940 static int __perf_cgroup_move(void *info) 10941 { 10942 struct task_struct *task = info; 10943 rcu_read_lock(); 10944 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN); 10945 rcu_read_unlock(); 10946 return 0; 10947 } 10948 10949 static void perf_cgroup_attach(struct cgroup_taskset *tset) 10950 { 10951 struct task_struct *task; 10952 struct cgroup_subsys_state *css; 10953 10954 cgroup_taskset_for_each(task, css, tset) 10955 task_function_call(task, __perf_cgroup_move, task); 10956 } 10957 10958 struct cgroup_subsys perf_event_cgrp_subsys = { 10959 .css_alloc = perf_cgroup_css_alloc, 10960 .css_free = perf_cgroup_css_free, 10961 .attach = perf_cgroup_attach, 10962 }; 10963 #endif /* CONFIG_CGROUP_PERF */ 10964