1 /* 2 * Performance events core code: 3 * 4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de> 5 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar 6 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra 7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com> 8 * 9 * For licensing details see kernel-base/COPYING 10 */ 11 12 #include <linux/fs.h> 13 #include <linux/mm.h> 14 #include <linux/cpu.h> 15 #include <linux/smp.h> 16 #include <linux/idr.h> 17 #include <linux/file.h> 18 #include <linux/poll.h> 19 #include <linux/slab.h> 20 #include <linux/hash.h> 21 #include <linux/tick.h> 22 #include <linux/sysfs.h> 23 #include <linux/dcache.h> 24 #include <linux/percpu.h> 25 #include <linux/ptrace.h> 26 #include <linux/reboot.h> 27 #include <linux/vmstat.h> 28 #include <linux/device.h> 29 #include <linux/export.h> 30 #include <linux/vmalloc.h> 31 #include <linux/hardirq.h> 32 #include <linux/rculist.h> 33 #include <linux/uaccess.h> 34 #include <linux/syscalls.h> 35 #include <linux/anon_inodes.h> 36 #include <linux/kernel_stat.h> 37 #include <linux/cgroup.h> 38 #include <linux/perf_event.h> 39 #include <linux/trace_events.h> 40 #include <linux/hw_breakpoint.h> 41 #include <linux/mm_types.h> 42 #include <linux/module.h> 43 #include <linux/mman.h> 44 #include <linux/compat.h> 45 #include <linux/bpf.h> 46 #include <linux/filter.h> 47 #include <linux/namei.h> 48 #include <linux/parser.h> 49 #include <linux/sched/clock.h> 50 #include <linux/sched/mm.h> 51 #include <linux/proc_ns.h> 52 #include <linux/mount.h> 53 54 #include "internal.h" 55 56 #include <asm/irq_regs.h> 57 58 typedef int (*remote_function_f)(void *); 59 60 struct remote_function_call { 61 struct task_struct *p; 62 remote_function_f func; 63 void *info; 64 int ret; 65 }; 66 67 static void remote_function(void *data) 68 { 69 struct remote_function_call *tfc = data; 70 struct task_struct *p = tfc->p; 71 72 if (p) { 73 /* -EAGAIN */ 74 if (task_cpu(p) != smp_processor_id()) 75 return; 76 77 /* 78 * Now that we're on right CPU with IRQs disabled, we can test 79 * if we hit the right task without races. 80 */ 81 82 tfc->ret = -ESRCH; /* No such (running) process */ 83 if (p != current) 84 return; 85 } 86 87 tfc->ret = tfc->func(tfc->info); 88 } 89 90 /** 91 * task_function_call - call a function on the cpu on which a task runs 92 * @p: the task to evaluate 93 * @func: the function to be called 94 * @info: the function call argument 95 * 96 * Calls the function @func when the task is currently running. This might 97 * be on the current CPU, which just calls the function directly 98 * 99 * returns: @func return value, or 100 * -ESRCH - when the process isn't running 101 * -EAGAIN - when the process moved away 102 */ 103 static int 104 task_function_call(struct task_struct *p, remote_function_f func, void *info) 105 { 106 struct remote_function_call data = { 107 .p = p, 108 .func = func, 109 .info = info, 110 .ret = -EAGAIN, 111 }; 112 int ret; 113 114 do { 115 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1); 116 if (!ret) 117 ret = data.ret; 118 } while (ret == -EAGAIN); 119 120 return ret; 121 } 122 123 /** 124 * cpu_function_call - call a function on the cpu 125 * @func: the function to be called 126 * @info: the function call argument 127 * 128 * Calls the function @func on the remote cpu. 129 * 130 * returns: @func return value or -ENXIO when the cpu is offline 131 */ 132 static int cpu_function_call(int cpu, remote_function_f func, void *info) 133 { 134 struct remote_function_call data = { 135 .p = NULL, 136 .func = func, 137 .info = info, 138 .ret = -ENXIO, /* No such CPU */ 139 }; 140 141 smp_call_function_single(cpu, remote_function, &data, 1); 142 143 return data.ret; 144 } 145 146 static inline struct perf_cpu_context * 147 __get_cpu_context(struct perf_event_context *ctx) 148 { 149 return this_cpu_ptr(ctx->pmu->pmu_cpu_context); 150 } 151 152 static void perf_ctx_lock(struct perf_cpu_context *cpuctx, 153 struct perf_event_context *ctx) 154 { 155 raw_spin_lock(&cpuctx->ctx.lock); 156 if (ctx) 157 raw_spin_lock(&ctx->lock); 158 } 159 160 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx, 161 struct perf_event_context *ctx) 162 { 163 if (ctx) 164 raw_spin_unlock(&ctx->lock); 165 raw_spin_unlock(&cpuctx->ctx.lock); 166 } 167 168 #define TASK_TOMBSTONE ((void *)-1L) 169 170 static bool is_kernel_event(struct perf_event *event) 171 { 172 return READ_ONCE(event->owner) == TASK_TOMBSTONE; 173 } 174 175 /* 176 * On task ctx scheduling... 177 * 178 * When !ctx->nr_events a task context will not be scheduled. This means 179 * we can disable the scheduler hooks (for performance) without leaving 180 * pending task ctx state. 181 * 182 * This however results in two special cases: 183 * 184 * - removing the last event from a task ctx; this is relatively straight 185 * forward and is done in __perf_remove_from_context. 186 * 187 * - adding the first event to a task ctx; this is tricky because we cannot 188 * rely on ctx->is_active and therefore cannot use event_function_call(). 189 * See perf_install_in_context(). 190 * 191 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set. 192 */ 193 194 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *, 195 struct perf_event_context *, void *); 196 197 struct event_function_struct { 198 struct perf_event *event; 199 event_f func; 200 void *data; 201 }; 202 203 static int event_function(void *info) 204 { 205 struct event_function_struct *efs = info; 206 struct perf_event *event = efs->event; 207 struct perf_event_context *ctx = event->ctx; 208 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 209 struct perf_event_context *task_ctx = cpuctx->task_ctx; 210 int ret = 0; 211 212 WARN_ON_ONCE(!irqs_disabled()); 213 214 perf_ctx_lock(cpuctx, task_ctx); 215 /* 216 * Since we do the IPI call without holding ctx->lock things can have 217 * changed, double check we hit the task we set out to hit. 218 */ 219 if (ctx->task) { 220 if (ctx->task != current) { 221 ret = -ESRCH; 222 goto unlock; 223 } 224 225 /* 226 * We only use event_function_call() on established contexts, 227 * and event_function() is only ever called when active (or 228 * rather, we'll have bailed in task_function_call() or the 229 * above ctx->task != current test), therefore we must have 230 * ctx->is_active here. 231 */ 232 WARN_ON_ONCE(!ctx->is_active); 233 /* 234 * And since we have ctx->is_active, cpuctx->task_ctx must 235 * match. 236 */ 237 WARN_ON_ONCE(task_ctx != ctx); 238 } else { 239 WARN_ON_ONCE(&cpuctx->ctx != ctx); 240 } 241 242 efs->func(event, cpuctx, ctx, efs->data); 243 unlock: 244 perf_ctx_unlock(cpuctx, task_ctx); 245 246 return ret; 247 } 248 249 static void event_function_call(struct perf_event *event, event_f func, void *data) 250 { 251 struct perf_event_context *ctx = event->ctx; 252 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */ 253 struct event_function_struct efs = { 254 .event = event, 255 .func = func, 256 .data = data, 257 }; 258 259 if (!event->parent) { 260 /* 261 * If this is a !child event, we must hold ctx::mutex to 262 * stabilize the the event->ctx relation. See 263 * perf_event_ctx_lock(). 264 */ 265 lockdep_assert_held(&ctx->mutex); 266 } 267 268 if (!task) { 269 cpu_function_call(event->cpu, event_function, &efs); 270 return; 271 } 272 273 if (task == TASK_TOMBSTONE) 274 return; 275 276 again: 277 if (!task_function_call(task, event_function, &efs)) 278 return; 279 280 raw_spin_lock_irq(&ctx->lock); 281 /* 282 * Reload the task pointer, it might have been changed by 283 * a concurrent perf_event_context_sched_out(). 284 */ 285 task = ctx->task; 286 if (task == TASK_TOMBSTONE) { 287 raw_spin_unlock_irq(&ctx->lock); 288 return; 289 } 290 if (ctx->is_active) { 291 raw_spin_unlock_irq(&ctx->lock); 292 goto again; 293 } 294 func(event, NULL, ctx, data); 295 raw_spin_unlock_irq(&ctx->lock); 296 } 297 298 /* 299 * Similar to event_function_call() + event_function(), but hard assumes IRQs 300 * are already disabled and we're on the right CPU. 301 */ 302 static void event_function_local(struct perf_event *event, event_f func, void *data) 303 { 304 struct perf_event_context *ctx = event->ctx; 305 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 306 struct task_struct *task = READ_ONCE(ctx->task); 307 struct perf_event_context *task_ctx = NULL; 308 309 WARN_ON_ONCE(!irqs_disabled()); 310 311 if (task) { 312 if (task == TASK_TOMBSTONE) 313 return; 314 315 task_ctx = ctx; 316 } 317 318 perf_ctx_lock(cpuctx, task_ctx); 319 320 task = ctx->task; 321 if (task == TASK_TOMBSTONE) 322 goto unlock; 323 324 if (task) { 325 /* 326 * We must be either inactive or active and the right task, 327 * otherwise we're screwed, since we cannot IPI to somewhere 328 * else. 329 */ 330 if (ctx->is_active) { 331 if (WARN_ON_ONCE(task != current)) 332 goto unlock; 333 334 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx)) 335 goto unlock; 336 } 337 } else { 338 WARN_ON_ONCE(&cpuctx->ctx != ctx); 339 } 340 341 func(event, cpuctx, ctx, data); 342 unlock: 343 perf_ctx_unlock(cpuctx, task_ctx); 344 } 345 346 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\ 347 PERF_FLAG_FD_OUTPUT |\ 348 PERF_FLAG_PID_CGROUP |\ 349 PERF_FLAG_FD_CLOEXEC) 350 351 /* 352 * branch priv levels that need permission checks 353 */ 354 #define PERF_SAMPLE_BRANCH_PERM_PLM \ 355 (PERF_SAMPLE_BRANCH_KERNEL |\ 356 PERF_SAMPLE_BRANCH_HV) 357 358 enum event_type_t { 359 EVENT_FLEXIBLE = 0x1, 360 EVENT_PINNED = 0x2, 361 EVENT_TIME = 0x4, 362 /* see ctx_resched() for details */ 363 EVENT_CPU = 0x8, 364 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED, 365 }; 366 367 /* 368 * perf_sched_events : >0 events exist 369 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu 370 */ 371 372 static void perf_sched_delayed(struct work_struct *work); 373 DEFINE_STATIC_KEY_FALSE(perf_sched_events); 374 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed); 375 static DEFINE_MUTEX(perf_sched_mutex); 376 static atomic_t perf_sched_count; 377 378 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events); 379 static DEFINE_PER_CPU(int, perf_sched_cb_usages); 380 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events); 381 382 static atomic_t nr_mmap_events __read_mostly; 383 static atomic_t nr_comm_events __read_mostly; 384 static atomic_t nr_namespaces_events __read_mostly; 385 static atomic_t nr_task_events __read_mostly; 386 static atomic_t nr_freq_events __read_mostly; 387 static atomic_t nr_switch_events __read_mostly; 388 389 static LIST_HEAD(pmus); 390 static DEFINE_MUTEX(pmus_lock); 391 static struct srcu_struct pmus_srcu; 392 static cpumask_var_t perf_online_mask; 393 394 /* 395 * perf event paranoia level: 396 * -1 - not paranoid at all 397 * 0 - disallow raw tracepoint access for unpriv 398 * 1 - disallow cpu events for unpriv 399 * 2 - disallow kernel profiling for unpriv 400 */ 401 int sysctl_perf_event_paranoid __read_mostly = 2; 402 403 /* Minimum for 512 kiB + 1 user control page */ 404 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */ 405 406 /* 407 * max perf event sample rate 408 */ 409 #define DEFAULT_MAX_SAMPLE_RATE 100000 410 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE) 411 #define DEFAULT_CPU_TIME_MAX_PERCENT 25 412 413 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE; 414 415 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ); 416 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS; 417 418 static int perf_sample_allowed_ns __read_mostly = 419 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100; 420 421 static void update_perf_cpu_limits(void) 422 { 423 u64 tmp = perf_sample_period_ns; 424 425 tmp *= sysctl_perf_cpu_time_max_percent; 426 tmp = div_u64(tmp, 100); 427 if (!tmp) 428 tmp = 1; 429 430 WRITE_ONCE(perf_sample_allowed_ns, tmp); 431 } 432 433 static int perf_rotate_context(struct perf_cpu_context *cpuctx); 434 435 int perf_proc_update_handler(struct ctl_table *table, int write, 436 void __user *buffer, size_t *lenp, 437 loff_t *ppos) 438 { 439 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); 440 441 if (ret || !write) 442 return ret; 443 444 /* 445 * If throttling is disabled don't allow the write: 446 */ 447 if (sysctl_perf_cpu_time_max_percent == 100 || 448 sysctl_perf_cpu_time_max_percent == 0) 449 return -EINVAL; 450 451 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ); 452 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; 453 update_perf_cpu_limits(); 454 455 return 0; 456 } 457 458 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT; 459 460 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write, 461 void __user *buffer, size_t *lenp, 462 loff_t *ppos) 463 { 464 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); 465 466 if (ret || !write) 467 return ret; 468 469 if (sysctl_perf_cpu_time_max_percent == 100 || 470 sysctl_perf_cpu_time_max_percent == 0) { 471 printk(KERN_WARNING 472 "perf: Dynamic interrupt throttling disabled, can hang your system!\n"); 473 WRITE_ONCE(perf_sample_allowed_ns, 0); 474 } else { 475 update_perf_cpu_limits(); 476 } 477 478 return 0; 479 } 480 481 /* 482 * perf samples are done in some very critical code paths (NMIs). 483 * If they take too much CPU time, the system can lock up and not 484 * get any real work done. This will drop the sample rate when 485 * we detect that events are taking too long. 486 */ 487 #define NR_ACCUMULATED_SAMPLES 128 488 static DEFINE_PER_CPU(u64, running_sample_length); 489 490 static u64 __report_avg; 491 static u64 __report_allowed; 492 493 static void perf_duration_warn(struct irq_work *w) 494 { 495 printk_ratelimited(KERN_INFO 496 "perf: interrupt took too long (%lld > %lld), lowering " 497 "kernel.perf_event_max_sample_rate to %d\n", 498 __report_avg, __report_allowed, 499 sysctl_perf_event_sample_rate); 500 } 501 502 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn); 503 504 void perf_sample_event_took(u64 sample_len_ns) 505 { 506 u64 max_len = READ_ONCE(perf_sample_allowed_ns); 507 u64 running_len; 508 u64 avg_len; 509 u32 max; 510 511 if (max_len == 0) 512 return; 513 514 /* Decay the counter by 1 average sample. */ 515 running_len = __this_cpu_read(running_sample_length); 516 running_len -= running_len/NR_ACCUMULATED_SAMPLES; 517 running_len += sample_len_ns; 518 __this_cpu_write(running_sample_length, running_len); 519 520 /* 521 * Note: this will be biased artifically low until we have 522 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us 523 * from having to maintain a count. 524 */ 525 avg_len = running_len/NR_ACCUMULATED_SAMPLES; 526 if (avg_len <= max_len) 527 return; 528 529 __report_avg = avg_len; 530 __report_allowed = max_len; 531 532 /* 533 * Compute a throttle threshold 25% below the current duration. 534 */ 535 avg_len += avg_len / 4; 536 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent; 537 if (avg_len < max) 538 max /= (u32)avg_len; 539 else 540 max = 1; 541 542 WRITE_ONCE(perf_sample_allowed_ns, avg_len); 543 WRITE_ONCE(max_samples_per_tick, max); 544 545 sysctl_perf_event_sample_rate = max * HZ; 546 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; 547 548 if (!irq_work_queue(&perf_duration_work)) { 549 early_printk("perf: interrupt took too long (%lld > %lld), lowering " 550 "kernel.perf_event_max_sample_rate to %d\n", 551 __report_avg, __report_allowed, 552 sysctl_perf_event_sample_rate); 553 } 554 } 555 556 static atomic64_t perf_event_id; 557 558 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, 559 enum event_type_t event_type); 560 561 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, 562 enum event_type_t event_type, 563 struct task_struct *task); 564 565 static void update_context_time(struct perf_event_context *ctx); 566 static u64 perf_event_time(struct perf_event *event); 567 568 void __weak perf_event_print_debug(void) { } 569 570 extern __weak const char *perf_pmu_name(void) 571 { 572 return "pmu"; 573 } 574 575 static inline u64 perf_clock(void) 576 { 577 return local_clock(); 578 } 579 580 static inline u64 perf_event_clock(struct perf_event *event) 581 { 582 return event->clock(); 583 } 584 585 #ifdef CONFIG_CGROUP_PERF 586 587 static inline bool 588 perf_cgroup_match(struct perf_event *event) 589 { 590 struct perf_event_context *ctx = event->ctx; 591 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 592 593 /* @event doesn't care about cgroup */ 594 if (!event->cgrp) 595 return true; 596 597 /* wants specific cgroup scope but @cpuctx isn't associated with any */ 598 if (!cpuctx->cgrp) 599 return false; 600 601 /* 602 * Cgroup scoping is recursive. An event enabled for a cgroup is 603 * also enabled for all its descendant cgroups. If @cpuctx's 604 * cgroup is a descendant of @event's (the test covers identity 605 * case), it's a match. 606 */ 607 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup, 608 event->cgrp->css.cgroup); 609 } 610 611 static inline void perf_detach_cgroup(struct perf_event *event) 612 { 613 css_put(&event->cgrp->css); 614 event->cgrp = NULL; 615 } 616 617 static inline int is_cgroup_event(struct perf_event *event) 618 { 619 return event->cgrp != NULL; 620 } 621 622 static inline u64 perf_cgroup_event_time(struct perf_event *event) 623 { 624 struct perf_cgroup_info *t; 625 626 t = per_cpu_ptr(event->cgrp->info, event->cpu); 627 return t->time; 628 } 629 630 static inline void __update_cgrp_time(struct perf_cgroup *cgrp) 631 { 632 struct perf_cgroup_info *info; 633 u64 now; 634 635 now = perf_clock(); 636 637 info = this_cpu_ptr(cgrp->info); 638 639 info->time += now - info->timestamp; 640 info->timestamp = now; 641 } 642 643 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) 644 { 645 struct perf_cgroup *cgrp_out = cpuctx->cgrp; 646 if (cgrp_out) 647 __update_cgrp_time(cgrp_out); 648 } 649 650 static inline void update_cgrp_time_from_event(struct perf_event *event) 651 { 652 struct perf_cgroup *cgrp; 653 654 /* 655 * ensure we access cgroup data only when needed and 656 * when we know the cgroup is pinned (css_get) 657 */ 658 if (!is_cgroup_event(event)) 659 return; 660 661 cgrp = perf_cgroup_from_task(current, event->ctx); 662 /* 663 * Do not update time when cgroup is not active 664 */ 665 if (cgrp == event->cgrp) 666 __update_cgrp_time(event->cgrp); 667 } 668 669 static inline void 670 perf_cgroup_set_timestamp(struct task_struct *task, 671 struct perf_event_context *ctx) 672 { 673 struct perf_cgroup *cgrp; 674 struct perf_cgroup_info *info; 675 676 /* 677 * ctx->lock held by caller 678 * ensure we do not access cgroup data 679 * unless we have the cgroup pinned (css_get) 680 */ 681 if (!task || !ctx->nr_cgroups) 682 return; 683 684 cgrp = perf_cgroup_from_task(task, ctx); 685 info = this_cpu_ptr(cgrp->info); 686 info->timestamp = ctx->timestamp; 687 } 688 689 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list); 690 691 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */ 692 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */ 693 694 /* 695 * reschedule events based on the cgroup constraint of task. 696 * 697 * mode SWOUT : schedule out everything 698 * mode SWIN : schedule in based on cgroup for next 699 */ 700 static void perf_cgroup_switch(struct task_struct *task, int mode) 701 { 702 struct perf_cpu_context *cpuctx; 703 struct list_head *list; 704 unsigned long flags; 705 706 /* 707 * Disable interrupts and preemption to avoid this CPU's 708 * cgrp_cpuctx_entry to change under us. 709 */ 710 local_irq_save(flags); 711 712 list = this_cpu_ptr(&cgrp_cpuctx_list); 713 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) { 714 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0); 715 716 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 717 perf_pmu_disable(cpuctx->ctx.pmu); 718 719 if (mode & PERF_CGROUP_SWOUT) { 720 cpu_ctx_sched_out(cpuctx, EVENT_ALL); 721 /* 722 * must not be done before ctxswout due 723 * to event_filter_match() in event_sched_out() 724 */ 725 cpuctx->cgrp = NULL; 726 } 727 728 if (mode & PERF_CGROUP_SWIN) { 729 WARN_ON_ONCE(cpuctx->cgrp); 730 /* 731 * set cgrp before ctxsw in to allow 732 * event_filter_match() to not have to pass 733 * task around 734 * we pass the cpuctx->ctx to perf_cgroup_from_task() 735 * because cgorup events are only per-cpu 736 */ 737 cpuctx->cgrp = perf_cgroup_from_task(task, 738 &cpuctx->ctx); 739 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task); 740 } 741 perf_pmu_enable(cpuctx->ctx.pmu); 742 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 743 } 744 745 local_irq_restore(flags); 746 } 747 748 static inline void perf_cgroup_sched_out(struct task_struct *task, 749 struct task_struct *next) 750 { 751 struct perf_cgroup *cgrp1; 752 struct perf_cgroup *cgrp2 = NULL; 753 754 rcu_read_lock(); 755 /* 756 * we come here when we know perf_cgroup_events > 0 757 * we do not need to pass the ctx here because we know 758 * we are holding the rcu lock 759 */ 760 cgrp1 = perf_cgroup_from_task(task, NULL); 761 cgrp2 = perf_cgroup_from_task(next, NULL); 762 763 /* 764 * only schedule out current cgroup events if we know 765 * that we are switching to a different cgroup. Otherwise, 766 * do no touch the cgroup events. 767 */ 768 if (cgrp1 != cgrp2) 769 perf_cgroup_switch(task, PERF_CGROUP_SWOUT); 770 771 rcu_read_unlock(); 772 } 773 774 static inline void perf_cgroup_sched_in(struct task_struct *prev, 775 struct task_struct *task) 776 { 777 struct perf_cgroup *cgrp1; 778 struct perf_cgroup *cgrp2 = NULL; 779 780 rcu_read_lock(); 781 /* 782 * we come here when we know perf_cgroup_events > 0 783 * we do not need to pass the ctx here because we know 784 * we are holding the rcu lock 785 */ 786 cgrp1 = perf_cgroup_from_task(task, NULL); 787 cgrp2 = perf_cgroup_from_task(prev, NULL); 788 789 /* 790 * only need to schedule in cgroup events if we are changing 791 * cgroup during ctxsw. Cgroup events were not scheduled 792 * out of ctxsw out if that was not the case. 793 */ 794 if (cgrp1 != cgrp2) 795 perf_cgroup_switch(task, PERF_CGROUP_SWIN); 796 797 rcu_read_unlock(); 798 } 799 800 static inline int perf_cgroup_connect(int fd, struct perf_event *event, 801 struct perf_event_attr *attr, 802 struct perf_event *group_leader) 803 { 804 struct perf_cgroup *cgrp; 805 struct cgroup_subsys_state *css; 806 struct fd f = fdget(fd); 807 int ret = 0; 808 809 if (!f.file) 810 return -EBADF; 811 812 css = css_tryget_online_from_dir(f.file->f_path.dentry, 813 &perf_event_cgrp_subsys); 814 if (IS_ERR(css)) { 815 ret = PTR_ERR(css); 816 goto out; 817 } 818 819 cgrp = container_of(css, struct perf_cgroup, css); 820 event->cgrp = cgrp; 821 822 /* 823 * all events in a group must monitor 824 * the same cgroup because a task belongs 825 * to only one perf cgroup at a time 826 */ 827 if (group_leader && group_leader->cgrp != cgrp) { 828 perf_detach_cgroup(event); 829 ret = -EINVAL; 830 } 831 out: 832 fdput(f); 833 return ret; 834 } 835 836 static inline void 837 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) 838 { 839 struct perf_cgroup_info *t; 840 t = per_cpu_ptr(event->cgrp->info, event->cpu); 841 event->shadow_ctx_time = now - t->timestamp; 842 } 843 844 static inline void 845 perf_cgroup_defer_enabled(struct perf_event *event) 846 { 847 /* 848 * when the current task's perf cgroup does not match 849 * the event's, we need to remember to call the 850 * perf_mark_enable() function the first time a task with 851 * a matching perf cgroup is scheduled in. 852 */ 853 if (is_cgroup_event(event) && !perf_cgroup_match(event)) 854 event->cgrp_defer_enabled = 1; 855 } 856 857 static inline void 858 perf_cgroup_mark_enabled(struct perf_event *event, 859 struct perf_event_context *ctx) 860 { 861 struct perf_event *sub; 862 u64 tstamp = perf_event_time(event); 863 864 if (!event->cgrp_defer_enabled) 865 return; 866 867 event->cgrp_defer_enabled = 0; 868 869 event->tstamp_enabled = tstamp - event->total_time_enabled; 870 list_for_each_entry(sub, &event->sibling_list, group_entry) { 871 if (sub->state >= PERF_EVENT_STATE_INACTIVE) { 872 sub->tstamp_enabled = tstamp - sub->total_time_enabled; 873 sub->cgrp_defer_enabled = 0; 874 } 875 } 876 } 877 878 /* 879 * Update cpuctx->cgrp so that it is set when first cgroup event is added and 880 * cleared when last cgroup event is removed. 881 */ 882 static inline void 883 list_update_cgroup_event(struct perf_event *event, 884 struct perf_event_context *ctx, bool add) 885 { 886 struct perf_cpu_context *cpuctx; 887 struct list_head *cpuctx_entry; 888 889 if (!is_cgroup_event(event)) 890 return; 891 892 if (add && ctx->nr_cgroups++) 893 return; 894 else if (!add && --ctx->nr_cgroups) 895 return; 896 /* 897 * Because cgroup events are always per-cpu events, 898 * this will always be called from the right CPU. 899 */ 900 cpuctx = __get_cpu_context(ctx); 901 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry; 902 /* cpuctx->cgrp is NULL unless a cgroup event is active in this CPU .*/ 903 if (add) { 904 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list)); 905 if (perf_cgroup_from_task(current, ctx) == event->cgrp) 906 cpuctx->cgrp = event->cgrp; 907 } else { 908 list_del(cpuctx_entry); 909 cpuctx->cgrp = NULL; 910 } 911 } 912 913 #else /* !CONFIG_CGROUP_PERF */ 914 915 static inline bool 916 perf_cgroup_match(struct perf_event *event) 917 { 918 return true; 919 } 920 921 static inline void perf_detach_cgroup(struct perf_event *event) 922 {} 923 924 static inline int is_cgroup_event(struct perf_event *event) 925 { 926 return 0; 927 } 928 929 static inline void update_cgrp_time_from_event(struct perf_event *event) 930 { 931 } 932 933 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) 934 { 935 } 936 937 static inline void perf_cgroup_sched_out(struct task_struct *task, 938 struct task_struct *next) 939 { 940 } 941 942 static inline void perf_cgroup_sched_in(struct task_struct *prev, 943 struct task_struct *task) 944 { 945 } 946 947 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event, 948 struct perf_event_attr *attr, 949 struct perf_event *group_leader) 950 { 951 return -EINVAL; 952 } 953 954 static inline void 955 perf_cgroup_set_timestamp(struct task_struct *task, 956 struct perf_event_context *ctx) 957 { 958 } 959 960 void 961 perf_cgroup_switch(struct task_struct *task, struct task_struct *next) 962 { 963 } 964 965 static inline void 966 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) 967 { 968 } 969 970 static inline u64 perf_cgroup_event_time(struct perf_event *event) 971 { 972 return 0; 973 } 974 975 static inline void 976 perf_cgroup_defer_enabled(struct perf_event *event) 977 { 978 } 979 980 static inline void 981 perf_cgroup_mark_enabled(struct perf_event *event, 982 struct perf_event_context *ctx) 983 { 984 } 985 986 static inline void 987 list_update_cgroup_event(struct perf_event *event, 988 struct perf_event_context *ctx, bool add) 989 { 990 } 991 992 #endif 993 994 /* 995 * set default to be dependent on timer tick just 996 * like original code 997 */ 998 #define PERF_CPU_HRTIMER (1000 / HZ) 999 /* 1000 * function must be called with interrupts disabled 1001 */ 1002 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr) 1003 { 1004 struct perf_cpu_context *cpuctx; 1005 int rotations = 0; 1006 1007 WARN_ON(!irqs_disabled()); 1008 1009 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer); 1010 rotations = perf_rotate_context(cpuctx); 1011 1012 raw_spin_lock(&cpuctx->hrtimer_lock); 1013 if (rotations) 1014 hrtimer_forward_now(hr, cpuctx->hrtimer_interval); 1015 else 1016 cpuctx->hrtimer_active = 0; 1017 raw_spin_unlock(&cpuctx->hrtimer_lock); 1018 1019 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART; 1020 } 1021 1022 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu) 1023 { 1024 struct hrtimer *timer = &cpuctx->hrtimer; 1025 struct pmu *pmu = cpuctx->ctx.pmu; 1026 u64 interval; 1027 1028 /* no multiplexing needed for SW PMU */ 1029 if (pmu->task_ctx_nr == perf_sw_context) 1030 return; 1031 1032 /* 1033 * check default is sane, if not set then force to 1034 * default interval (1/tick) 1035 */ 1036 interval = pmu->hrtimer_interval_ms; 1037 if (interval < 1) 1038 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER; 1039 1040 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval); 1041 1042 raw_spin_lock_init(&cpuctx->hrtimer_lock); 1043 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED); 1044 timer->function = perf_mux_hrtimer_handler; 1045 } 1046 1047 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx) 1048 { 1049 struct hrtimer *timer = &cpuctx->hrtimer; 1050 struct pmu *pmu = cpuctx->ctx.pmu; 1051 unsigned long flags; 1052 1053 /* not for SW PMU */ 1054 if (pmu->task_ctx_nr == perf_sw_context) 1055 return 0; 1056 1057 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags); 1058 if (!cpuctx->hrtimer_active) { 1059 cpuctx->hrtimer_active = 1; 1060 hrtimer_forward_now(timer, cpuctx->hrtimer_interval); 1061 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED); 1062 } 1063 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags); 1064 1065 return 0; 1066 } 1067 1068 void perf_pmu_disable(struct pmu *pmu) 1069 { 1070 int *count = this_cpu_ptr(pmu->pmu_disable_count); 1071 if (!(*count)++) 1072 pmu->pmu_disable(pmu); 1073 } 1074 1075 void perf_pmu_enable(struct pmu *pmu) 1076 { 1077 int *count = this_cpu_ptr(pmu->pmu_disable_count); 1078 if (!--(*count)) 1079 pmu->pmu_enable(pmu); 1080 } 1081 1082 static DEFINE_PER_CPU(struct list_head, active_ctx_list); 1083 1084 /* 1085 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and 1086 * perf_event_task_tick() are fully serialized because they're strictly cpu 1087 * affine and perf_event_ctx{activate,deactivate} are called with IRQs 1088 * disabled, while perf_event_task_tick is called from IRQ context. 1089 */ 1090 static void perf_event_ctx_activate(struct perf_event_context *ctx) 1091 { 1092 struct list_head *head = this_cpu_ptr(&active_ctx_list); 1093 1094 WARN_ON(!irqs_disabled()); 1095 1096 WARN_ON(!list_empty(&ctx->active_ctx_list)); 1097 1098 list_add(&ctx->active_ctx_list, head); 1099 } 1100 1101 static void perf_event_ctx_deactivate(struct perf_event_context *ctx) 1102 { 1103 WARN_ON(!irqs_disabled()); 1104 1105 WARN_ON(list_empty(&ctx->active_ctx_list)); 1106 1107 list_del_init(&ctx->active_ctx_list); 1108 } 1109 1110 static void get_ctx(struct perf_event_context *ctx) 1111 { 1112 WARN_ON(!atomic_inc_not_zero(&ctx->refcount)); 1113 } 1114 1115 static void free_ctx(struct rcu_head *head) 1116 { 1117 struct perf_event_context *ctx; 1118 1119 ctx = container_of(head, struct perf_event_context, rcu_head); 1120 kfree(ctx->task_ctx_data); 1121 kfree(ctx); 1122 } 1123 1124 static void put_ctx(struct perf_event_context *ctx) 1125 { 1126 if (atomic_dec_and_test(&ctx->refcount)) { 1127 if (ctx->parent_ctx) 1128 put_ctx(ctx->parent_ctx); 1129 if (ctx->task && ctx->task != TASK_TOMBSTONE) 1130 put_task_struct(ctx->task); 1131 call_rcu(&ctx->rcu_head, free_ctx); 1132 } 1133 } 1134 1135 /* 1136 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and 1137 * perf_pmu_migrate_context() we need some magic. 1138 * 1139 * Those places that change perf_event::ctx will hold both 1140 * perf_event_ctx::mutex of the 'old' and 'new' ctx value. 1141 * 1142 * Lock ordering is by mutex address. There are two other sites where 1143 * perf_event_context::mutex nests and those are: 1144 * 1145 * - perf_event_exit_task_context() [ child , 0 ] 1146 * perf_event_exit_event() 1147 * put_event() [ parent, 1 ] 1148 * 1149 * - perf_event_init_context() [ parent, 0 ] 1150 * inherit_task_group() 1151 * inherit_group() 1152 * inherit_event() 1153 * perf_event_alloc() 1154 * perf_init_event() 1155 * perf_try_init_event() [ child , 1 ] 1156 * 1157 * While it appears there is an obvious deadlock here -- the parent and child 1158 * nesting levels are inverted between the two. This is in fact safe because 1159 * life-time rules separate them. That is an exiting task cannot fork, and a 1160 * spawning task cannot (yet) exit. 1161 * 1162 * But remember that that these are parent<->child context relations, and 1163 * migration does not affect children, therefore these two orderings should not 1164 * interact. 1165 * 1166 * The change in perf_event::ctx does not affect children (as claimed above) 1167 * because the sys_perf_event_open() case will install a new event and break 1168 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only 1169 * concerned with cpuctx and that doesn't have children. 1170 * 1171 * The places that change perf_event::ctx will issue: 1172 * 1173 * perf_remove_from_context(); 1174 * synchronize_rcu(); 1175 * perf_install_in_context(); 1176 * 1177 * to affect the change. The remove_from_context() + synchronize_rcu() should 1178 * quiesce the event, after which we can install it in the new location. This 1179 * means that only external vectors (perf_fops, prctl) can perturb the event 1180 * while in transit. Therefore all such accessors should also acquire 1181 * perf_event_context::mutex to serialize against this. 1182 * 1183 * However; because event->ctx can change while we're waiting to acquire 1184 * ctx->mutex we must be careful and use the below perf_event_ctx_lock() 1185 * function. 1186 * 1187 * Lock order: 1188 * cred_guard_mutex 1189 * task_struct::perf_event_mutex 1190 * perf_event_context::mutex 1191 * perf_event::child_mutex; 1192 * perf_event_context::lock 1193 * perf_event::mmap_mutex 1194 * mmap_sem 1195 */ 1196 static struct perf_event_context * 1197 perf_event_ctx_lock_nested(struct perf_event *event, int nesting) 1198 { 1199 struct perf_event_context *ctx; 1200 1201 again: 1202 rcu_read_lock(); 1203 ctx = ACCESS_ONCE(event->ctx); 1204 if (!atomic_inc_not_zero(&ctx->refcount)) { 1205 rcu_read_unlock(); 1206 goto again; 1207 } 1208 rcu_read_unlock(); 1209 1210 mutex_lock_nested(&ctx->mutex, nesting); 1211 if (event->ctx != ctx) { 1212 mutex_unlock(&ctx->mutex); 1213 put_ctx(ctx); 1214 goto again; 1215 } 1216 1217 return ctx; 1218 } 1219 1220 static inline struct perf_event_context * 1221 perf_event_ctx_lock(struct perf_event *event) 1222 { 1223 return perf_event_ctx_lock_nested(event, 0); 1224 } 1225 1226 static void perf_event_ctx_unlock(struct perf_event *event, 1227 struct perf_event_context *ctx) 1228 { 1229 mutex_unlock(&ctx->mutex); 1230 put_ctx(ctx); 1231 } 1232 1233 /* 1234 * This must be done under the ctx->lock, such as to serialize against 1235 * context_equiv(), therefore we cannot call put_ctx() since that might end up 1236 * calling scheduler related locks and ctx->lock nests inside those. 1237 */ 1238 static __must_check struct perf_event_context * 1239 unclone_ctx(struct perf_event_context *ctx) 1240 { 1241 struct perf_event_context *parent_ctx = ctx->parent_ctx; 1242 1243 lockdep_assert_held(&ctx->lock); 1244 1245 if (parent_ctx) 1246 ctx->parent_ctx = NULL; 1247 ctx->generation++; 1248 1249 return parent_ctx; 1250 } 1251 1252 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) 1253 { 1254 /* 1255 * only top level events have the pid namespace they were created in 1256 */ 1257 if (event->parent) 1258 event = event->parent; 1259 1260 return task_tgid_nr_ns(p, event->ns); 1261 } 1262 1263 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) 1264 { 1265 /* 1266 * only top level events have the pid namespace they were created in 1267 */ 1268 if (event->parent) 1269 event = event->parent; 1270 1271 return task_pid_nr_ns(p, event->ns); 1272 } 1273 1274 /* 1275 * If we inherit events we want to return the parent event id 1276 * to userspace. 1277 */ 1278 static u64 primary_event_id(struct perf_event *event) 1279 { 1280 u64 id = event->id; 1281 1282 if (event->parent) 1283 id = event->parent->id; 1284 1285 return id; 1286 } 1287 1288 /* 1289 * Get the perf_event_context for a task and lock it. 1290 * 1291 * This has to cope with with the fact that until it is locked, 1292 * the context could get moved to another task. 1293 */ 1294 static struct perf_event_context * 1295 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags) 1296 { 1297 struct perf_event_context *ctx; 1298 1299 retry: 1300 /* 1301 * One of the few rules of preemptible RCU is that one cannot do 1302 * rcu_read_unlock() while holding a scheduler (or nested) lock when 1303 * part of the read side critical section was irqs-enabled -- see 1304 * rcu_read_unlock_special(). 1305 * 1306 * Since ctx->lock nests under rq->lock we must ensure the entire read 1307 * side critical section has interrupts disabled. 1308 */ 1309 local_irq_save(*flags); 1310 rcu_read_lock(); 1311 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]); 1312 if (ctx) { 1313 /* 1314 * If this context is a clone of another, it might 1315 * get swapped for another underneath us by 1316 * perf_event_task_sched_out, though the 1317 * rcu_read_lock() protects us from any context 1318 * getting freed. Lock the context and check if it 1319 * got swapped before we could get the lock, and retry 1320 * if so. If we locked the right context, then it 1321 * can't get swapped on us any more. 1322 */ 1323 raw_spin_lock(&ctx->lock); 1324 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) { 1325 raw_spin_unlock(&ctx->lock); 1326 rcu_read_unlock(); 1327 local_irq_restore(*flags); 1328 goto retry; 1329 } 1330 1331 if (ctx->task == TASK_TOMBSTONE || 1332 !atomic_inc_not_zero(&ctx->refcount)) { 1333 raw_spin_unlock(&ctx->lock); 1334 ctx = NULL; 1335 } else { 1336 WARN_ON_ONCE(ctx->task != task); 1337 } 1338 } 1339 rcu_read_unlock(); 1340 if (!ctx) 1341 local_irq_restore(*flags); 1342 return ctx; 1343 } 1344 1345 /* 1346 * Get the context for a task and increment its pin_count so it 1347 * can't get swapped to another task. This also increments its 1348 * reference count so that the context can't get freed. 1349 */ 1350 static struct perf_event_context * 1351 perf_pin_task_context(struct task_struct *task, int ctxn) 1352 { 1353 struct perf_event_context *ctx; 1354 unsigned long flags; 1355 1356 ctx = perf_lock_task_context(task, ctxn, &flags); 1357 if (ctx) { 1358 ++ctx->pin_count; 1359 raw_spin_unlock_irqrestore(&ctx->lock, flags); 1360 } 1361 return ctx; 1362 } 1363 1364 static void perf_unpin_context(struct perf_event_context *ctx) 1365 { 1366 unsigned long flags; 1367 1368 raw_spin_lock_irqsave(&ctx->lock, flags); 1369 --ctx->pin_count; 1370 raw_spin_unlock_irqrestore(&ctx->lock, flags); 1371 } 1372 1373 /* 1374 * Update the record of the current time in a context. 1375 */ 1376 static void update_context_time(struct perf_event_context *ctx) 1377 { 1378 u64 now = perf_clock(); 1379 1380 ctx->time += now - ctx->timestamp; 1381 ctx->timestamp = now; 1382 } 1383 1384 static u64 perf_event_time(struct perf_event *event) 1385 { 1386 struct perf_event_context *ctx = event->ctx; 1387 1388 if (is_cgroup_event(event)) 1389 return perf_cgroup_event_time(event); 1390 1391 return ctx ? ctx->time : 0; 1392 } 1393 1394 /* 1395 * Update the total_time_enabled and total_time_running fields for a event. 1396 */ 1397 static void update_event_times(struct perf_event *event) 1398 { 1399 struct perf_event_context *ctx = event->ctx; 1400 u64 run_end; 1401 1402 lockdep_assert_held(&ctx->lock); 1403 1404 if (event->state < PERF_EVENT_STATE_INACTIVE || 1405 event->group_leader->state < PERF_EVENT_STATE_INACTIVE) 1406 return; 1407 1408 /* 1409 * in cgroup mode, time_enabled represents 1410 * the time the event was enabled AND active 1411 * tasks were in the monitored cgroup. This is 1412 * independent of the activity of the context as 1413 * there may be a mix of cgroup and non-cgroup events. 1414 * 1415 * That is why we treat cgroup events differently 1416 * here. 1417 */ 1418 if (is_cgroup_event(event)) 1419 run_end = perf_cgroup_event_time(event); 1420 else if (ctx->is_active) 1421 run_end = ctx->time; 1422 else 1423 run_end = event->tstamp_stopped; 1424 1425 event->total_time_enabled = run_end - event->tstamp_enabled; 1426 1427 if (event->state == PERF_EVENT_STATE_INACTIVE) 1428 run_end = event->tstamp_stopped; 1429 else 1430 run_end = perf_event_time(event); 1431 1432 event->total_time_running = run_end - event->tstamp_running; 1433 1434 } 1435 1436 /* 1437 * Update total_time_enabled and total_time_running for all events in a group. 1438 */ 1439 static void update_group_times(struct perf_event *leader) 1440 { 1441 struct perf_event *event; 1442 1443 update_event_times(leader); 1444 list_for_each_entry(event, &leader->sibling_list, group_entry) 1445 update_event_times(event); 1446 } 1447 1448 static enum event_type_t get_event_type(struct perf_event *event) 1449 { 1450 struct perf_event_context *ctx = event->ctx; 1451 enum event_type_t event_type; 1452 1453 lockdep_assert_held(&ctx->lock); 1454 1455 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE; 1456 if (!ctx->task) 1457 event_type |= EVENT_CPU; 1458 1459 return event_type; 1460 } 1461 1462 static struct list_head * 1463 ctx_group_list(struct perf_event *event, struct perf_event_context *ctx) 1464 { 1465 if (event->attr.pinned) 1466 return &ctx->pinned_groups; 1467 else 1468 return &ctx->flexible_groups; 1469 } 1470 1471 /* 1472 * Add a event from the lists for its context. 1473 * Must be called with ctx->mutex and ctx->lock held. 1474 */ 1475 static void 1476 list_add_event(struct perf_event *event, struct perf_event_context *ctx) 1477 { 1478 lockdep_assert_held(&ctx->lock); 1479 1480 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); 1481 event->attach_state |= PERF_ATTACH_CONTEXT; 1482 1483 /* 1484 * If we're a stand alone event or group leader, we go to the context 1485 * list, group events are kept attached to the group so that 1486 * perf_group_detach can, at all times, locate all siblings. 1487 */ 1488 if (event->group_leader == event) { 1489 struct list_head *list; 1490 1491 event->group_caps = event->event_caps; 1492 1493 list = ctx_group_list(event, ctx); 1494 list_add_tail(&event->group_entry, list); 1495 } 1496 1497 list_update_cgroup_event(event, ctx, true); 1498 1499 list_add_rcu(&event->event_entry, &ctx->event_list); 1500 ctx->nr_events++; 1501 if (event->attr.inherit_stat) 1502 ctx->nr_stat++; 1503 1504 ctx->generation++; 1505 } 1506 1507 /* 1508 * Initialize event state based on the perf_event_attr::disabled. 1509 */ 1510 static inline void perf_event__state_init(struct perf_event *event) 1511 { 1512 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF : 1513 PERF_EVENT_STATE_INACTIVE; 1514 } 1515 1516 static void __perf_event_read_size(struct perf_event *event, int nr_siblings) 1517 { 1518 int entry = sizeof(u64); /* value */ 1519 int size = 0; 1520 int nr = 1; 1521 1522 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 1523 size += sizeof(u64); 1524 1525 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 1526 size += sizeof(u64); 1527 1528 if (event->attr.read_format & PERF_FORMAT_ID) 1529 entry += sizeof(u64); 1530 1531 if (event->attr.read_format & PERF_FORMAT_GROUP) { 1532 nr += nr_siblings; 1533 size += sizeof(u64); 1534 } 1535 1536 size += entry * nr; 1537 event->read_size = size; 1538 } 1539 1540 static void __perf_event_header_size(struct perf_event *event, u64 sample_type) 1541 { 1542 struct perf_sample_data *data; 1543 u16 size = 0; 1544 1545 if (sample_type & PERF_SAMPLE_IP) 1546 size += sizeof(data->ip); 1547 1548 if (sample_type & PERF_SAMPLE_ADDR) 1549 size += sizeof(data->addr); 1550 1551 if (sample_type & PERF_SAMPLE_PERIOD) 1552 size += sizeof(data->period); 1553 1554 if (sample_type & PERF_SAMPLE_WEIGHT) 1555 size += sizeof(data->weight); 1556 1557 if (sample_type & PERF_SAMPLE_READ) 1558 size += event->read_size; 1559 1560 if (sample_type & PERF_SAMPLE_DATA_SRC) 1561 size += sizeof(data->data_src.val); 1562 1563 if (sample_type & PERF_SAMPLE_TRANSACTION) 1564 size += sizeof(data->txn); 1565 1566 event->header_size = size; 1567 } 1568 1569 /* 1570 * Called at perf_event creation and when events are attached/detached from a 1571 * group. 1572 */ 1573 static void perf_event__header_size(struct perf_event *event) 1574 { 1575 __perf_event_read_size(event, 1576 event->group_leader->nr_siblings); 1577 __perf_event_header_size(event, event->attr.sample_type); 1578 } 1579 1580 static void perf_event__id_header_size(struct perf_event *event) 1581 { 1582 struct perf_sample_data *data; 1583 u64 sample_type = event->attr.sample_type; 1584 u16 size = 0; 1585 1586 if (sample_type & PERF_SAMPLE_TID) 1587 size += sizeof(data->tid_entry); 1588 1589 if (sample_type & PERF_SAMPLE_TIME) 1590 size += sizeof(data->time); 1591 1592 if (sample_type & PERF_SAMPLE_IDENTIFIER) 1593 size += sizeof(data->id); 1594 1595 if (sample_type & PERF_SAMPLE_ID) 1596 size += sizeof(data->id); 1597 1598 if (sample_type & PERF_SAMPLE_STREAM_ID) 1599 size += sizeof(data->stream_id); 1600 1601 if (sample_type & PERF_SAMPLE_CPU) 1602 size += sizeof(data->cpu_entry); 1603 1604 event->id_header_size = size; 1605 } 1606 1607 static bool perf_event_validate_size(struct perf_event *event) 1608 { 1609 /* 1610 * The values computed here will be over-written when we actually 1611 * attach the event. 1612 */ 1613 __perf_event_read_size(event, event->group_leader->nr_siblings + 1); 1614 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ); 1615 perf_event__id_header_size(event); 1616 1617 /* 1618 * Sum the lot; should not exceed the 64k limit we have on records. 1619 * Conservative limit to allow for callchains and other variable fields. 1620 */ 1621 if (event->read_size + event->header_size + 1622 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024) 1623 return false; 1624 1625 return true; 1626 } 1627 1628 static void perf_group_attach(struct perf_event *event) 1629 { 1630 struct perf_event *group_leader = event->group_leader, *pos; 1631 1632 lockdep_assert_held(&event->ctx->lock); 1633 1634 /* 1635 * We can have double attach due to group movement in perf_event_open. 1636 */ 1637 if (event->attach_state & PERF_ATTACH_GROUP) 1638 return; 1639 1640 event->attach_state |= PERF_ATTACH_GROUP; 1641 1642 if (group_leader == event) 1643 return; 1644 1645 WARN_ON_ONCE(group_leader->ctx != event->ctx); 1646 1647 group_leader->group_caps &= event->event_caps; 1648 1649 list_add_tail(&event->group_entry, &group_leader->sibling_list); 1650 group_leader->nr_siblings++; 1651 1652 perf_event__header_size(group_leader); 1653 1654 list_for_each_entry(pos, &group_leader->sibling_list, group_entry) 1655 perf_event__header_size(pos); 1656 } 1657 1658 /* 1659 * Remove a event from the lists for its context. 1660 * Must be called with ctx->mutex and ctx->lock held. 1661 */ 1662 static void 1663 list_del_event(struct perf_event *event, struct perf_event_context *ctx) 1664 { 1665 WARN_ON_ONCE(event->ctx != ctx); 1666 lockdep_assert_held(&ctx->lock); 1667 1668 /* 1669 * We can have double detach due to exit/hot-unplug + close. 1670 */ 1671 if (!(event->attach_state & PERF_ATTACH_CONTEXT)) 1672 return; 1673 1674 event->attach_state &= ~PERF_ATTACH_CONTEXT; 1675 1676 list_update_cgroup_event(event, ctx, false); 1677 1678 ctx->nr_events--; 1679 if (event->attr.inherit_stat) 1680 ctx->nr_stat--; 1681 1682 list_del_rcu(&event->event_entry); 1683 1684 if (event->group_leader == event) 1685 list_del_init(&event->group_entry); 1686 1687 update_group_times(event); 1688 1689 /* 1690 * If event was in error state, then keep it 1691 * that way, otherwise bogus counts will be 1692 * returned on read(). The only way to get out 1693 * of error state is by explicit re-enabling 1694 * of the event 1695 */ 1696 if (event->state > PERF_EVENT_STATE_OFF) 1697 event->state = PERF_EVENT_STATE_OFF; 1698 1699 ctx->generation++; 1700 } 1701 1702 static void perf_group_detach(struct perf_event *event) 1703 { 1704 struct perf_event *sibling, *tmp; 1705 struct list_head *list = NULL; 1706 1707 lockdep_assert_held(&event->ctx->lock); 1708 1709 /* 1710 * We can have double detach due to exit/hot-unplug + close. 1711 */ 1712 if (!(event->attach_state & PERF_ATTACH_GROUP)) 1713 return; 1714 1715 event->attach_state &= ~PERF_ATTACH_GROUP; 1716 1717 /* 1718 * If this is a sibling, remove it from its group. 1719 */ 1720 if (event->group_leader != event) { 1721 list_del_init(&event->group_entry); 1722 event->group_leader->nr_siblings--; 1723 goto out; 1724 } 1725 1726 if (!list_empty(&event->group_entry)) 1727 list = &event->group_entry; 1728 1729 /* 1730 * If this was a group event with sibling events then 1731 * upgrade the siblings to singleton events by adding them 1732 * to whatever list we are on. 1733 */ 1734 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) { 1735 if (list) 1736 list_move_tail(&sibling->group_entry, list); 1737 sibling->group_leader = sibling; 1738 1739 /* Inherit group flags from the previous leader */ 1740 sibling->group_caps = event->group_caps; 1741 1742 WARN_ON_ONCE(sibling->ctx != event->ctx); 1743 } 1744 1745 out: 1746 perf_event__header_size(event->group_leader); 1747 1748 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry) 1749 perf_event__header_size(tmp); 1750 } 1751 1752 static bool is_orphaned_event(struct perf_event *event) 1753 { 1754 return event->state == PERF_EVENT_STATE_DEAD; 1755 } 1756 1757 static inline int __pmu_filter_match(struct perf_event *event) 1758 { 1759 struct pmu *pmu = event->pmu; 1760 return pmu->filter_match ? pmu->filter_match(event) : 1; 1761 } 1762 1763 /* 1764 * Check whether we should attempt to schedule an event group based on 1765 * PMU-specific filtering. An event group can consist of HW and SW events, 1766 * potentially with a SW leader, so we must check all the filters, to 1767 * determine whether a group is schedulable: 1768 */ 1769 static inline int pmu_filter_match(struct perf_event *event) 1770 { 1771 struct perf_event *child; 1772 1773 if (!__pmu_filter_match(event)) 1774 return 0; 1775 1776 list_for_each_entry(child, &event->sibling_list, group_entry) { 1777 if (!__pmu_filter_match(child)) 1778 return 0; 1779 } 1780 1781 return 1; 1782 } 1783 1784 static inline int 1785 event_filter_match(struct perf_event *event) 1786 { 1787 return (event->cpu == -1 || event->cpu == smp_processor_id()) && 1788 perf_cgroup_match(event) && pmu_filter_match(event); 1789 } 1790 1791 static void 1792 event_sched_out(struct perf_event *event, 1793 struct perf_cpu_context *cpuctx, 1794 struct perf_event_context *ctx) 1795 { 1796 u64 tstamp = perf_event_time(event); 1797 u64 delta; 1798 1799 WARN_ON_ONCE(event->ctx != ctx); 1800 lockdep_assert_held(&ctx->lock); 1801 1802 /* 1803 * An event which could not be activated because of 1804 * filter mismatch still needs to have its timings 1805 * maintained, otherwise bogus information is return 1806 * via read() for time_enabled, time_running: 1807 */ 1808 if (event->state == PERF_EVENT_STATE_INACTIVE && 1809 !event_filter_match(event)) { 1810 delta = tstamp - event->tstamp_stopped; 1811 event->tstamp_running += delta; 1812 event->tstamp_stopped = tstamp; 1813 } 1814 1815 if (event->state != PERF_EVENT_STATE_ACTIVE) 1816 return; 1817 1818 perf_pmu_disable(event->pmu); 1819 1820 event->tstamp_stopped = tstamp; 1821 event->pmu->del(event, 0); 1822 event->oncpu = -1; 1823 event->state = PERF_EVENT_STATE_INACTIVE; 1824 if (event->pending_disable) { 1825 event->pending_disable = 0; 1826 event->state = PERF_EVENT_STATE_OFF; 1827 } 1828 1829 if (!is_software_event(event)) 1830 cpuctx->active_oncpu--; 1831 if (!--ctx->nr_active) 1832 perf_event_ctx_deactivate(ctx); 1833 if (event->attr.freq && event->attr.sample_freq) 1834 ctx->nr_freq--; 1835 if (event->attr.exclusive || !cpuctx->active_oncpu) 1836 cpuctx->exclusive = 0; 1837 1838 perf_pmu_enable(event->pmu); 1839 } 1840 1841 static void 1842 group_sched_out(struct perf_event *group_event, 1843 struct perf_cpu_context *cpuctx, 1844 struct perf_event_context *ctx) 1845 { 1846 struct perf_event *event; 1847 int state = group_event->state; 1848 1849 perf_pmu_disable(ctx->pmu); 1850 1851 event_sched_out(group_event, cpuctx, ctx); 1852 1853 /* 1854 * Schedule out siblings (if any): 1855 */ 1856 list_for_each_entry(event, &group_event->sibling_list, group_entry) 1857 event_sched_out(event, cpuctx, ctx); 1858 1859 perf_pmu_enable(ctx->pmu); 1860 1861 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive) 1862 cpuctx->exclusive = 0; 1863 } 1864 1865 #define DETACH_GROUP 0x01UL 1866 1867 /* 1868 * Cross CPU call to remove a performance event 1869 * 1870 * We disable the event on the hardware level first. After that we 1871 * remove it from the context list. 1872 */ 1873 static void 1874 __perf_remove_from_context(struct perf_event *event, 1875 struct perf_cpu_context *cpuctx, 1876 struct perf_event_context *ctx, 1877 void *info) 1878 { 1879 unsigned long flags = (unsigned long)info; 1880 1881 event_sched_out(event, cpuctx, ctx); 1882 if (flags & DETACH_GROUP) 1883 perf_group_detach(event); 1884 list_del_event(event, ctx); 1885 1886 if (!ctx->nr_events && ctx->is_active) { 1887 ctx->is_active = 0; 1888 if (ctx->task) { 1889 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 1890 cpuctx->task_ctx = NULL; 1891 } 1892 } 1893 } 1894 1895 /* 1896 * Remove the event from a task's (or a CPU's) list of events. 1897 * 1898 * If event->ctx is a cloned context, callers must make sure that 1899 * every task struct that event->ctx->task could possibly point to 1900 * remains valid. This is OK when called from perf_release since 1901 * that only calls us on the top-level context, which can't be a clone. 1902 * When called from perf_event_exit_task, it's OK because the 1903 * context has been detached from its task. 1904 */ 1905 static void perf_remove_from_context(struct perf_event *event, unsigned long flags) 1906 { 1907 struct perf_event_context *ctx = event->ctx; 1908 1909 lockdep_assert_held(&ctx->mutex); 1910 1911 event_function_call(event, __perf_remove_from_context, (void *)flags); 1912 1913 /* 1914 * The above event_function_call() can NO-OP when it hits 1915 * TASK_TOMBSTONE. In that case we must already have been detached 1916 * from the context (by perf_event_exit_event()) but the grouping 1917 * might still be in-tact. 1918 */ 1919 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); 1920 if ((flags & DETACH_GROUP) && 1921 (event->attach_state & PERF_ATTACH_GROUP)) { 1922 /* 1923 * Since in that case we cannot possibly be scheduled, simply 1924 * detach now. 1925 */ 1926 raw_spin_lock_irq(&ctx->lock); 1927 perf_group_detach(event); 1928 raw_spin_unlock_irq(&ctx->lock); 1929 } 1930 } 1931 1932 /* 1933 * Cross CPU call to disable a performance event 1934 */ 1935 static void __perf_event_disable(struct perf_event *event, 1936 struct perf_cpu_context *cpuctx, 1937 struct perf_event_context *ctx, 1938 void *info) 1939 { 1940 if (event->state < PERF_EVENT_STATE_INACTIVE) 1941 return; 1942 1943 update_context_time(ctx); 1944 update_cgrp_time_from_event(event); 1945 update_group_times(event); 1946 if (event == event->group_leader) 1947 group_sched_out(event, cpuctx, ctx); 1948 else 1949 event_sched_out(event, cpuctx, ctx); 1950 event->state = PERF_EVENT_STATE_OFF; 1951 } 1952 1953 /* 1954 * Disable a event. 1955 * 1956 * If event->ctx is a cloned context, callers must make sure that 1957 * every task struct that event->ctx->task could possibly point to 1958 * remains valid. This condition is satisifed when called through 1959 * perf_event_for_each_child or perf_event_for_each because they 1960 * hold the top-level event's child_mutex, so any descendant that 1961 * goes to exit will block in perf_event_exit_event(). 1962 * 1963 * When called from perf_pending_event it's OK because event->ctx 1964 * is the current context on this CPU and preemption is disabled, 1965 * hence we can't get into perf_event_task_sched_out for this context. 1966 */ 1967 static void _perf_event_disable(struct perf_event *event) 1968 { 1969 struct perf_event_context *ctx = event->ctx; 1970 1971 raw_spin_lock_irq(&ctx->lock); 1972 if (event->state <= PERF_EVENT_STATE_OFF) { 1973 raw_spin_unlock_irq(&ctx->lock); 1974 return; 1975 } 1976 raw_spin_unlock_irq(&ctx->lock); 1977 1978 event_function_call(event, __perf_event_disable, NULL); 1979 } 1980 1981 void perf_event_disable_local(struct perf_event *event) 1982 { 1983 event_function_local(event, __perf_event_disable, NULL); 1984 } 1985 1986 /* 1987 * Strictly speaking kernel users cannot create groups and therefore this 1988 * interface does not need the perf_event_ctx_lock() magic. 1989 */ 1990 void perf_event_disable(struct perf_event *event) 1991 { 1992 struct perf_event_context *ctx; 1993 1994 ctx = perf_event_ctx_lock(event); 1995 _perf_event_disable(event); 1996 perf_event_ctx_unlock(event, ctx); 1997 } 1998 EXPORT_SYMBOL_GPL(perf_event_disable); 1999 2000 void perf_event_disable_inatomic(struct perf_event *event) 2001 { 2002 event->pending_disable = 1; 2003 irq_work_queue(&event->pending); 2004 } 2005 2006 static void perf_set_shadow_time(struct perf_event *event, 2007 struct perf_event_context *ctx, 2008 u64 tstamp) 2009 { 2010 /* 2011 * use the correct time source for the time snapshot 2012 * 2013 * We could get by without this by leveraging the 2014 * fact that to get to this function, the caller 2015 * has most likely already called update_context_time() 2016 * and update_cgrp_time_xx() and thus both timestamp 2017 * are identical (or very close). Given that tstamp is, 2018 * already adjusted for cgroup, we could say that: 2019 * tstamp - ctx->timestamp 2020 * is equivalent to 2021 * tstamp - cgrp->timestamp. 2022 * 2023 * Then, in perf_output_read(), the calculation would 2024 * work with no changes because: 2025 * - event is guaranteed scheduled in 2026 * - no scheduled out in between 2027 * - thus the timestamp would be the same 2028 * 2029 * But this is a bit hairy. 2030 * 2031 * So instead, we have an explicit cgroup call to remain 2032 * within the time time source all along. We believe it 2033 * is cleaner and simpler to understand. 2034 */ 2035 if (is_cgroup_event(event)) 2036 perf_cgroup_set_shadow_time(event, tstamp); 2037 else 2038 event->shadow_ctx_time = tstamp - ctx->timestamp; 2039 } 2040 2041 #define MAX_INTERRUPTS (~0ULL) 2042 2043 static void perf_log_throttle(struct perf_event *event, int enable); 2044 static void perf_log_itrace_start(struct perf_event *event); 2045 2046 static int 2047 event_sched_in(struct perf_event *event, 2048 struct perf_cpu_context *cpuctx, 2049 struct perf_event_context *ctx) 2050 { 2051 u64 tstamp = perf_event_time(event); 2052 int ret = 0; 2053 2054 lockdep_assert_held(&ctx->lock); 2055 2056 if (event->state <= PERF_EVENT_STATE_OFF) 2057 return 0; 2058 2059 WRITE_ONCE(event->oncpu, smp_processor_id()); 2060 /* 2061 * Order event::oncpu write to happen before the ACTIVE state 2062 * is visible. 2063 */ 2064 smp_wmb(); 2065 WRITE_ONCE(event->state, PERF_EVENT_STATE_ACTIVE); 2066 2067 /* 2068 * Unthrottle events, since we scheduled we might have missed several 2069 * ticks already, also for a heavily scheduling task there is little 2070 * guarantee it'll get a tick in a timely manner. 2071 */ 2072 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) { 2073 perf_log_throttle(event, 1); 2074 event->hw.interrupts = 0; 2075 } 2076 2077 /* 2078 * The new state must be visible before we turn it on in the hardware: 2079 */ 2080 smp_wmb(); 2081 2082 perf_pmu_disable(event->pmu); 2083 2084 perf_set_shadow_time(event, ctx, tstamp); 2085 2086 perf_log_itrace_start(event); 2087 2088 if (event->pmu->add(event, PERF_EF_START)) { 2089 event->state = PERF_EVENT_STATE_INACTIVE; 2090 event->oncpu = -1; 2091 ret = -EAGAIN; 2092 goto out; 2093 } 2094 2095 event->tstamp_running += tstamp - event->tstamp_stopped; 2096 2097 if (!is_software_event(event)) 2098 cpuctx->active_oncpu++; 2099 if (!ctx->nr_active++) 2100 perf_event_ctx_activate(ctx); 2101 if (event->attr.freq && event->attr.sample_freq) 2102 ctx->nr_freq++; 2103 2104 if (event->attr.exclusive) 2105 cpuctx->exclusive = 1; 2106 2107 out: 2108 perf_pmu_enable(event->pmu); 2109 2110 return ret; 2111 } 2112 2113 static int 2114 group_sched_in(struct perf_event *group_event, 2115 struct perf_cpu_context *cpuctx, 2116 struct perf_event_context *ctx) 2117 { 2118 struct perf_event *event, *partial_group = NULL; 2119 struct pmu *pmu = ctx->pmu; 2120 u64 now = ctx->time; 2121 bool simulate = false; 2122 2123 if (group_event->state == PERF_EVENT_STATE_OFF) 2124 return 0; 2125 2126 pmu->start_txn(pmu, PERF_PMU_TXN_ADD); 2127 2128 if (event_sched_in(group_event, cpuctx, ctx)) { 2129 pmu->cancel_txn(pmu); 2130 perf_mux_hrtimer_restart(cpuctx); 2131 return -EAGAIN; 2132 } 2133 2134 /* 2135 * Schedule in siblings as one group (if any): 2136 */ 2137 list_for_each_entry(event, &group_event->sibling_list, group_entry) { 2138 if (event_sched_in(event, cpuctx, ctx)) { 2139 partial_group = event; 2140 goto group_error; 2141 } 2142 } 2143 2144 if (!pmu->commit_txn(pmu)) 2145 return 0; 2146 2147 group_error: 2148 /* 2149 * Groups can be scheduled in as one unit only, so undo any 2150 * partial group before returning: 2151 * The events up to the failed event are scheduled out normally, 2152 * tstamp_stopped will be updated. 2153 * 2154 * The failed events and the remaining siblings need to have 2155 * their timings updated as if they had gone thru event_sched_in() 2156 * and event_sched_out(). This is required to get consistent timings 2157 * across the group. This also takes care of the case where the group 2158 * could never be scheduled by ensuring tstamp_stopped is set to mark 2159 * the time the event was actually stopped, such that time delta 2160 * calculation in update_event_times() is correct. 2161 */ 2162 list_for_each_entry(event, &group_event->sibling_list, group_entry) { 2163 if (event == partial_group) 2164 simulate = true; 2165 2166 if (simulate) { 2167 event->tstamp_running += now - event->tstamp_stopped; 2168 event->tstamp_stopped = now; 2169 } else { 2170 event_sched_out(event, cpuctx, ctx); 2171 } 2172 } 2173 event_sched_out(group_event, cpuctx, ctx); 2174 2175 pmu->cancel_txn(pmu); 2176 2177 perf_mux_hrtimer_restart(cpuctx); 2178 2179 return -EAGAIN; 2180 } 2181 2182 /* 2183 * Work out whether we can put this event group on the CPU now. 2184 */ 2185 static int group_can_go_on(struct perf_event *event, 2186 struct perf_cpu_context *cpuctx, 2187 int can_add_hw) 2188 { 2189 /* 2190 * Groups consisting entirely of software events can always go on. 2191 */ 2192 if (event->group_caps & PERF_EV_CAP_SOFTWARE) 2193 return 1; 2194 /* 2195 * If an exclusive group is already on, no other hardware 2196 * events can go on. 2197 */ 2198 if (cpuctx->exclusive) 2199 return 0; 2200 /* 2201 * If this group is exclusive and there are already 2202 * events on the CPU, it can't go on. 2203 */ 2204 if (event->attr.exclusive && cpuctx->active_oncpu) 2205 return 0; 2206 /* 2207 * Otherwise, try to add it if all previous groups were able 2208 * to go on. 2209 */ 2210 return can_add_hw; 2211 } 2212 2213 static void add_event_to_ctx(struct perf_event *event, 2214 struct perf_event_context *ctx) 2215 { 2216 u64 tstamp = perf_event_time(event); 2217 2218 list_add_event(event, ctx); 2219 perf_group_attach(event); 2220 event->tstamp_enabled = tstamp; 2221 event->tstamp_running = tstamp; 2222 event->tstamp_stopped = tstamp; 2223 } 2224 2225 static void ctx_sched_out(struct perf_event_context *ctx, 2226 struct perf_cpu_context *cpuctx, 2227 enum event_type_t event_type); 2228 static void 2229 ctx_sched_in(struct perf_event_context *ctx, 2230 struct perf_cpu_context *cpuctx, 2231 enum event_type_t event_type, 2232 struct task_struct *task); 2233 2234 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx, 2235 struct perf_event_context *ctx, 2236 enum event_type_t event_type) 2237 { 2238 if (!cpuctx->task_ctx) 2239 return; 2240 2241 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx)) 2242 return; 2243 2244 ctx_sched_out(ctx, cpuctx, event_type); 2245 } 2246 2247 static void perf_event_sched_in(struct perf_cpu_context *cpuctx, 2248 struct perf_event_context *ctx, 2249 struct task_struct *task) 2250 { 2251 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task); 2252 if (ctx) 2253 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task); 2254 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task); 2255 if (ctx) 2256 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task); 2257 } 2258 2259 /* 2260 * We want to maintain the following priority of scheduling: 2261 * - CPU pinned (EVENT_CPU | EVENT_PINNED) 2262 * - task pinned (EVENT_PINNED) 2263 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE) 2264 * - task flexible (EVENT_FLEXIBLE). 2265 * 2266 * In order to avoid unscheduling and scheduling back in everything every 2267 * time an event is added, only do it for the groups of equal priority and 2268 * below. 2269 * 2270 * This can be called after a batch operation on task events, in which case 2271 * event_type is a bit mask of the types of events involved. For CPU events, 2272 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE. 2273 */ 2274 static void ctx_resched(struct perf_cpu_context *cpuctx, 2275 struct perf_event_context *task_ctx, 2276 enum event_type_t event_type) 2277 { 2278 enum event_type_t ctx_event_type = event_type & EVENT_ALL; 2279 bool cpu_event = !!(event_type & EVENT_CPU); 2280 2281 /* 2282 * If pinned groups are involved, flexible groups also need to be 2283 * scheduled out. 2284 */ 2285 if (event_type & EVENT_PINNED) 2286 event_type |= EVENT_FLEXIBLE; 2287 2288 perf_pmu_disable(cpuctx->ctx.pmu); 2289 if (task_ctx) 2290 task_ctx_sched_out(cpuctx, task_ctx, event_type); 2291 2292 /* 2293 * Decide which cpu ctx groups to schedule out based on the types 2294 * of events that caused rescheduling: 2295 * - EVENT_CPU: schedule out corresponding groups; 2296 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups; 2297 * - otherwise, do nothing more. 2298 */ 2299 if (cpu_event) 2300 cpu_ctx_sched_out(cpuctx, ctx_event_type); 2301 else if (ctx_event_type & EVENT_PINNED) 2302 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); 2303 2304 perf_event_sched_in(cpuctx, task_ctx, current); 2305 perf_pmu_enable(cpuctx->ctx.pmu); 2306 } 2307 2308 /* 2309 * Cross CPU call to install and enable a performance event 2310 * 2311 * Very similar to remote_function() + event_function() but cannot assume that 2312 * things like ctx->is_active and cpuctx->task_ctx are set. 2313 */ 2314 static int __perf_install_in_context(void *info) 2315 { 2316 struct perf_event *event = info; 2317 struct perf_event_context *ctx = event->ctx; 2318 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 2319 struct perf_event_context *task_ctx = cpuctx->task_ctx; 2320 bool reprogram = true; 2321 int ret = 0; 2322 2323 raw_spin_lock(&cpuctx->ctx.lock); 2324 if (ctx->task) { 2325 raw_spin_lock(&ctx->lock); 2326 task_ctx = ctx; 2327 2328 reprogram = (ctx->task == current); 2329 2330 /* 2331 * If the task is running, it must be running on this CPU, 2332 * otherwise we cannot reprogram things. 2333 * 2334 * If its not running, we don't care, ctx->lock will 2335 * serialize against it becoming runnable. 2336 */ 2337 if (task_curr(ctx->task) && !reprogram) { 2338 ret = -ESRCH; 2339 goto unlock; 2340 } 2341 2342 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx); 2343 } else if (task_ctx) { 2344 raw_spin_lock(&task_ctx->lock); 2345 } 2346 2347 if (reprogram) { 2348 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 2349 add_event_to_ctx(event, ctx); 2350 ctx_resched(cpuctx, task_ctx, get_event_type(event)); 2351 } else { 2352 add_event_to_ctx(event, ctx); 2353 } 2354 2355 unlock: 2356 perf_ctx_unlock(cpuctx, task_ctx); 2357 2358 return ret; 2359 } 2360 2361 /* 2362 * Attach a performance event to a context. 2363 * 2364 * Very similar to event_function_call, see comment there. 2365 */ 2366 static void 2367 perf_install_in_context(struct perf_event_context *ctx, 2368 struct perf_event *event, 2369 int cpu) 2370 { 2371 struct task_struct *task = READ_ONCE(ctx->task); 2372 2373 lockdep_assert_held(&ctx->mutex); 2374 2375 if (event->cpu != -1) 2376 event->cpu = cpu; 2377 2378 /* 2379 * Ensures that if we can observe event->ctx, both the event and ctx 2380 * will be 'complete'. See perf_iterate_sb_cpu(). 2381 */ 2382 smp_store_release(&event->ctx, ctx); 2383 2384 if (!task) { 2385 cpu_function_call(cpu, __perf_install_in_context, event); 2386 return; 2387 } 2388 2389 /* 2390 * Should not happen, we validate the ctx is still alive before calling. 2391 */ 2392 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) 2393 return; 2394 2395 /* 2396 * Installing events is tricky because we cannot rely on ctx->is_active 2397 * to be set in case this is the nr_events 0 -> 1 transition. 2398 * 2399 * Instead we use task_curr(), which tells us if the task is running. 2400 * However, since we use task_curr() outside of rq::lock, we can race 2401 * against the actual state. This means the result can be wrong. 2402 * 2403 * If we get a false positive, we retry, this is harmless. 2404 * 2405 * If we get a false negative, things are complicated. If we are after 2406 * perf_event_context_sched_in() ctx::lock will serialize us, and the 2407 * value must be correct. If we're before, it doesn't matter since 2408 * perf_event_context_sched_in() will program the counter. 2409 * 2410 * However, this hinges on the remote context switch having observed 2411 * our task->perf_event_ctxp[] store, such that it will in fact take 2412 * ctx::lock in perf_event_context_sched_in(). 2413 * 2414 * We do this by task_function_call(), if the IPI fails to hit the task 2415 * we know any future context switch of task must see the 2416 * perf_event_ctpx[] store. 2417 */ 2418 2419 /* 2420 * This smp_mb() orders the task->perf_event_ctxp[] store with the 2421 * task_cpu() load, such that if the IPI then does not find the task 2422 * running, a future context switch of that task must observe the 2423 * store. 2424 */ 2425 smp_mb(); 2426 again: 2427 if (!task_function_call(task, __perf_install_in_context, event)) 2428 return; 2429 2430 raw_spin_lock_irq(&ctx->lock); 2431 task = ctx->task; 2432 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) { 2433 /* 2434 * Cannot happen because we already checked above (which also 2435 * cannot happen), and we hold ctx->mutex, which serializes us 2436 * against perf_event_exit_task_context(). 2437 */ 2438 raw_spin_unlock_irq(&ctx->lock); 2439 return; 2440 } 2441 /* 2442 * If the task is not running, ctx->lock will avoid it becoming so, 2443 * thus we can safely install the event. 2444 */ 2445 if (task_curr(task)) { 2446 raw_spin_unlock_irq(&ctx->lock); 2447 goto again; 2448 } 2449 add_event_to_ctx(event, ctx); 2450 raw_spin_unlock_irq(&ctx->lock); 2451 } 2452 2453 /* 2454 * Put a event into inactive state and update time fields. 2455 * Enabling the leader of a group effectively enables all 2456 * the group members that aren't explicitly disabled, so we 2457 * have to update their ->tstamp_enabled also. 2458 * Note: this works for group members as well as group leaders 2459 * since the non-leader members' sibling_lists will be empty. 2460 */ 2461 static void __perf_event_mark_enabled(struct perf_event *event) 2462 { 2463 struct perf_event *sub; 2464 u64 tstamp = perf_event_time(event); 2465 2466 event->state = PERF_EVENT_STATE_INACTIVE; 2467 event->tstamp_enabled = tstamp - event->total_time_enabled; 2468 list_for_each_entry(sub, &event->sibling_list, group_entry) { 2469 if (sub->state >= PERF_EVENT_STATE_INACTIVE) 2470 sub->tstamp_enabled = tstamp - sub->total_time_enabled; 2471 } 2472 } 2473 2474 /* 2475 * Cross CPU call to enable a performance event 2476 */ 2477 static void __perf_event_enable(struct perf_event *event, 2478 struct perf_cpu_context *cpuctx, 2479 struct perf_event_context *ctx, 2480 void *info) 2481 { 2482 struct perf_event *leader = event->group_leader; 2483 struct perf_event_context *task_ctx; 2484 2485 if (event->state >= PERF_EVENT_STATE_INACTIVE || 2486 event->state <= PERF_EVENT_STATE_ERROR) 2487 return; 2488 2489 if (ctx->is_active) 2490 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 2491 2492 __perf_event_mark_enabled(event); 2493 2494 if (!ctx->is_active) 2495 return; 2496 2497 if (!event_filter_match(event)) { 2498 if (is_cgroup_event(event)) 2499 perf_cgroup_defer_enabled(event); 2500 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current); 2501 return; 2502 } 2503 2504 /* 2505 * If the event is in a group and isn't the group leader, 2506 * then don't put it on unless the group is on. 2507 */ 2508 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) { 2509 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current); 2510 return; 2511 } 2512 2513 task_ctx = cpuctx->task_ctx; 2514 if (ctx->task) 2515 WARN_ON_ONCE(task_ctx != ctx); 2516 2517 ctx_resched(cpuctx, task_ctx, get_event_type(event)); 2518 } 2519 2520 /* 2521 * Enable a event. 2522 * 2523 * If event->ctx is a cloned context, callers must make sure that 2524 * every task struct that event->ctx->task could possibly point to 2525 * remains valid. This condition is satisfied when called through 2526 * perf_event_for_each_child or perf_event_for_each as described 2527 * for perf_event_disable. 2528 */ 2529 static void _perf_event_enable(struct perf_event *event) 2530 { 2531 struct perf_event_context *ctx = event->ctx; 2532 2533 raw_spin_lock_irq(&ctx->lock); 2534 if (event->state >= PERF_EVENT_STATE_INACTIVE || 2535 event->state < PERF_EVENT_STATE_ERROR) { 2536 raw_spin_unlock_irq(&ctx->lock); 2537 return; 2538 } 2539 2540 /* 2541 * If the event is in error state, clear that first. 2542 * 2543 * That way, if we see the event in error state below, we know that it 2544 * has gone back into error state, as distinct from the task having 2545 * been scheduled away before the cross-call arrived. 2546 */ 2547 if (event->state == PERF_EVENT_STATE_ERROR) 2548 event->state = PERF_EVENT_STATE_OFF; 2549 raw_spin_unlock_irq(&ctx->lock); 2550 2551 event_function_call(event, __perf_event_enable, NULL); 2552 } 2553 2554 /* 2555 * See perf_event_disable(); 2556 */ 2557 void perf_event_enable(struct perf_event *event) 2558 { 2559 struct perf_event_context *ctx; 2560 2561 ctx = perf_event_ctx_lock(event); 2562 _perf_event_enable(event); 2563 perf_event_ctx_unlock(event, ctx); 2564 } 2565 EXPORT_SYMBOL_GPL(perf_event_enable); 2566 2567 struct stop_event_data { 2568 struct perf_event *event; 2569 unsigned int restart; 2570 }; 2571 2572 static int __perf_event_stop(void *info) 2573 { 2574 struct stop_event_data *sd = info; 2575 struct perf_event *event = sd->event; 2576 2577 /* if it's already INACTIVE, do nothing */ 2578 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) 2579 return 0; 2580 2581 /* matches smp_wmb() in event_sched_in() */ 2582 smp_rmb(); 2583 2584 /* 2585 * There is a window with interrupts enabled before we get here, 2586 * so we need to check again lest we try to stop another CPU's event. 2587 */ 2588 if (READ_ONCE(event->oncpu) != smp_processor_id()) 2589 return -EAGAIN; 2590 2591 event->pmu->stop(event, PERF_EF_UPDATE); 2592 2593 /* 2594 * May race with the actual stop (through perf_pmu_output_stop()), 2595 * but it is only used for events with AUX ring buffer, and such 2596 * events will refuse to restart because of rb::aux_mmap_count==0, 2597 * see comments in perf_aux_output_begin(). 2598 * 2599 * Since this is happening on a event-local CPU, no trace is lost 2600 * while restarting. 2601 */ 2602 if (sd->restart) 2603 event->pmu->start(event, 0); 2604 2605 return 0; 2606 } 2607 2608 static int perf_event_stop(struct perf_event *event, int restart) 2609 { 2610 struct stop_event_data sd = { 2611 .event = event, 2612 .restart = restart, 2613 }; 2614 int ret = 0; 2615 2616 do { 2617 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) 2618 return 0; 2619 2620 /* matches smp_wmb() in event_sched_in() */ 2621 smp_rmb(); 2622 2623 /* 2624 * We only want to restart ACTIVE events, so if the event goes 2625 * inactive here (event->oncpu==-1), there's nothing more to do; 2626 * fall through with ret==-ENXIO. 2627 */ 2628 ret = cpu_function_call(READ_ONCE(event->oncpu), 2629 __perf_event_stop, &sd); 2630 } while (ret == -EAGAIN); 2631 2632 return ret; 2633 } 2634 2635 /* 2636 * In order to contain the amount of racy and tricky in the address filter 2637 * configuration management, it is a two part process: 2638 * 2639 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below, 2640 * we update the addresses of corresponding vmas in 2641 * event::addr_filters_offs array and bump the event::addr_filters_gen; 2642 * (p2) when an event is scheduled in (pmu::add), it calls 2643 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync() 2644 * if the generation has changed since the previous call. 2645 * 2646 * If (p1) happens while the event is active, we restart it to force (p2). 2647 * 2648 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on 2649 * pre-existing mappings, called once when new filters arrive via SET_FILTER 2650 * ioctl; 2651 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly 2652 * registered mapping, called for every new mmap(), with mm::mmap_sem down 2653 * for reading; 2654 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process 2655 * of exec. 2656 */ 2657 void perf_event_addr_filters_sync(struct perf_event *event) 2658 { 2659 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 2660 2661 if (!has_addr_filter(event)) 2662 return; 2663 2664 raw_spin_lock(&ifh->lock); 2665 if (event->addr_filters_gen != event->hw.addr_filters_gen) { 2666 event->pmu->addr_filters_sync(event); 2667 event->hw.addr_filters_gen = event->addr_filters_gen; 2668 } 2669 raw_spin_unlock(&ifh->lock); 2670 } 2671 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync); 2672 2673 static int _perf_event_refresh(struct perf_event *event, int refresh) 2674 { 2675 /* 2676 * not supported on inherited events 2677 */ 2678 if (event->attr.inherit || !is_sampling_event(event)) 2679 return -EINVAL; 2680 2681 atomic_add(refresh, &event->event_limit); 2682 _perf_event_enable(event); 2683 2684 return 0; 2685 } 2686 2687 /* 2688 * See perf_event_disable() 2689 */ 2690 int perf_event_refresh(struct perf_event *event, int refresh) 2691 { 2692 struct perf_event_context *ctx; 2693 int ret; 2694 2695 ctx = perf_event_ctx_lock(event); 2696 ret = _perf_event_refresh(event, refresh); 2697 perf_event_ctx_unlock(event, ctx); 2698 2699 return ret; 2700 } 2701 EXPORT_SYMBOL_GPL(perf_event_refresh); 2702 2703 static void ctx_sched_out(struct perf_event_context *ctx, 2704 struct perf_cpu_context *cpuctx, 2705 enum event_type_t event_type) 2706 { 2707 int is_active = ctx->is_active; 2708 struct perf_event *event; 2709 2710 lockdep_assert_held(&ctx->lock); 2711 2712 if (likely(!ctx->nr_events)) { 2713 /* 2714 * See __perf_remove_from_context(). 2715 */ 2716 WARN_ON_ONCE(ctx->is_active); 2717 if (ctx->task) 2718 WARN_ON_ONCE(cpuctx->task_ctx); 2719 return; 2720 } 2721 2722 ctx->is_active &= ~event_type; 2723 if (!(ctx->is_active & EVENT_ALL)) 2724 ctx->is_active = 0; 2725 2726 if (ctx->task) { 2727 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 2728 if (!ctx->is_active) 2729 cpuctx->task_ctx = NULL; 2730 } 2731 2732 /* 2733 * Always update time if it was set; not only when it changes. 2734 * Otherwise we can 'forget' to update time for any but the last 2735 * context we sched out. For example: 2736 * 2737 * ctx_sched_out(.event_type = EVENT_FLEXIBLE) 2738 * ctx_sched_out(.event_type = EVENT_PINNED) 2739 * 2740 * would only update time for the pinned events. 2741 */ 2742 if (is_active & EVENT_TIME) { 2743 /* update (and stop) ctx time */ 2744 update_context_time(ctx); 2745 update_cgrp_time_from_cpuctx(cpuctx); 2746 } 2747 2748 is_active ^= ctx->is_active; /* changed bits */ 2749 2750 if (!ctx->nr_active || !(is_active & EVENT_ALL)) 2751 return; 2752 2753 perf_pmu_disable(ctx->pmu); 2754 if (is_active & EVENT_PINNED) { 2755 list_for_each_entry(event, &ctx->pinned_groups, group_entry) 2756 group_sched_out(event, cpuctx, ctx); 2757 } 2758 2759 if (is_active & EVENT_FLEXIBLE) { 2760 list_for_each_entry(event, &ctx->flexible_groups, group_entry) 2761 group_sched_out(event, cpuctx, ctx); 2762 } 2763 perf_pmu_enable(ctx->pmu); 2764 } 2765 2766 /* 2767 * Test whether two contexts are equivalent, i.e. whether they have both been 2768 * cloned from the same version of the same context. 2769 * 2770 * Equivalence is measured using a generation number in the context that is 2771 * incremented on each modification to it; see unclone_ctx(), list_add_event() 2772 * and list_del_event(). 2773 */ 2774 static int context_equiv(struct perf_event_context *ctx1, 2775 struct perf_event_context *ctx2) 2776 { 2777 lockdep_assert_held(&ctx1->lock); 2778 lockdep_assert_held(&ctx2->lock); 2779 2780 /* Pinning disables the swap optimization */ 2781 if (ctx1->pin_count || ctx2->pin_count) 2782 return 0; 2783 2784 /* If ctx1 is the parent of ctx2 */ 2785 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen) 2786 return 1; 2787 2788 /* If ctx2 is the parent of ctx1 */ 2789 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation) 2790 return 1; 2791 2792 /* 2793 * If ctx1 and ctx2 have the same parent; we flatten the parent 2794 * hierarchy, see perf_event_init_context(). 2795 */ 2796 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx && 2797 ctx1->parent_gen == ctx2->parent_gen) 2798 return 1; 2799 2800 /* Unmatched */ 2801 return 0; 2802 } 2803 2804 static void __perf_event_sync_stat(struct perf_event *event, 2805 struct perf_event *next_event) 2806 { 2807 u64 value; 2808 2809 if (!event->attr.inherit_stat) 2810 return; 2811 2812 /* 2813 * Update the event value, we cannot use perf_event_read() 2814 * because we're in the middle of a context switch and have IRQs 2815 * disabled, which upsets smp_call_function_single(), however 2816 * we know the event must be on the current CPU, therefore we 2817 * don't need to use it. 2818 */ 2819 switch (event->state) { 2820 case PERF_EVENT_STATE_ACTIVE: 2821 event->pmu->read(event); 2822 /* fall-through */ 2823 2824 case PERF_EVENT_STATE_INACTIVE: 2825 update_event_times(event); 2826 break; 2827 2828 default: 2829 break; 2830 } 2831 2832 /* 2833 * In order to keep per-task stats reliable we need to flip the event 2834 * values when we flip the contexts. 2835 */ 2836 value = local64_read(&next_event->count); 2837 value = local64_xchg(&event->count, value); 2838 local64_set(&next_event->count, value); 2839 2840 swap(event->total_time_enabled, next_event->total_time_enabled); 2841 swap(event->total_time_running, next_event->total_time_running); 2842 2843 /* 2844 * Since we swizzled the values, update the user visible data too. 2845 */ 2846 perf_event_update_userpage(event); 2847 perf_event_update_userpage(next_event); 2848 } 2849 2850 static void perf_event_sync_stat(struct perf_event_context *ctx, 2851 struct perf_event_context *next_ctx) 2852 { 2853 struct perf_event *event, *next_event; 2854 2855 if (!ctx->nr_stat) 2856 return; 2857 2858 update_context_time(ctx); 2859 2860 event = list_first_entry(&ctx->event_list, 2861 struct perf_event, event_entry); 2862 2863 next_event = list_first_entry(&next_ctx->event_list, 2864 struct perf_event, event_entry); 2865 2866 while (&event->event_entry != &ctx->event_list && 2867 &next_event->event_entry != &next_ctx->event_list) { 2868 2869 __perf_event_sync_stat(event, next_event); 2870 2871 event = list_next_entry(event, event_entry); 2872 next_event = list_next_entry(next_event, event_entry); 2873 } 2874 } 2875 2876 static void perf_event_context_sched_out(struct task_struct *task, int ctxn, 2877 struct task_struct *next) 2878 { 2879 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn]; 2880 struct perf_event_context *next_ctx; 2881 struct perf_event_context *parent, *next_parent; 2882 struct perf_cpu_context *cpuctx; 2883 int do_switch = 1; 2884 2885 if (likely(!ctx)) 2886 return; 2887 2888 cpuctx = __get_cpu_context(ctx); 2889 if (!cpuctx->task_ctx) 2890 return; 2891 2892 rcu_read_lock(); 2893 next_ctx = next->perf_event_ctxp[ctxn]; 2894 if (!next_ctx) 2895 goto unlock; 2896 2897 parent = rcu_dereference(ctx->parent_ctx); 2898 next_parent = rcu_dereference(next_ctx->parent_ctx); 2899 2900 /* If neither context have a parent context; they cannot be clones. */ 2901 if (!parent && !next_parent) 2902 goto unlock; 2903 2904 if (next_parent == ctx || next_ctx == parent || next_parent == parent) { 2905 /* 2906 * Looks like the two contexts are clones, so we might be 2907 * able to optimize the context switch. We lock both 2908 * contexts and check that they are clones under the 2909 * lock (including re-checking that neither has been 2910 * uncloned in the meantime). It doesn't matter which 2911 * order we take the locks because no other cpu could 2912 * be trying to lock both of these tasks. 2913 */ 2914 raw_spin_lock(&ctx->lock); 2915 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING); 2916 if (context_equiv(ctx, next_ctx)) { 2917 WRITE_ONCE(ctx->task, next); 2918 WRITE_ONCE(next_ctx->task, task); 2919 2920 swap(ctx->task_ctx_data, next_ctx->task_ctx_data); 2921 2922 /* 2923 * RCU_INIT_POINTER here is safe because we've not 2924 * modified the ctx and the above modification of 2925 * ctx->task and ctx->task_ctx_data are immaterial 2926 * since those values are always verified under 2927 * ctx->lock which we're now holding. 2928 */ 2929 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx); 2930 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx); 2931 2932 do_switch = 0; 2933 2934 perf_event_sync_stat(ctx, next_ctx); 2935 } 2936 raw_spin_unlock(&next_ctx->lock); 2937 raw_spin_unlock(&ctx->lock); 2938 } 2939 unlock: 2940 rcu_read_unlock(); 2941 2942 if (do_switch) { 2943 raw_spin_lock(&ctx->lock); 2944 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL); 2945 raw_spin_unlock(&ctx->lock); 2946 } 2947 } 2948 2949 static DEFINE_PER_CPU(struct list_head, sched_cb_list); 2950 2951 void perf_sched_cb_dec(struct pmu *pmu) 2952 { 2953 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 2954 2955 this_cpu_dec(perf_sched_cb_usages); 2956 2957 if (!--cpuctx->sched_cb_usage) 2958 list_del(&cpuctx->sched_cb_entry); 2959 } 2960 2961 2962 void perf_sched_cb_inc(struct pmu *pmu) 2963 { 2964 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 2965 2966 if (!cpuctx->sched_cb_usage++) 2967 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list)); 2968 2969 this_cpu_inc(perf_sched_cb_usages); 2970 } 2971 2972 /* 2973 * This function provides the context switch callback to the lower code 2974 * layer. It is invoked ONLY when the context switch callback is enabled. 2975 * 2976 * This callback is relevant even to per-cpu events; for example multi event 2977 * PEBS requires this to provide PID/TID information. This requires we flush 2978 * all queued PEBS records before we context switch to a new task. 2979 */ 2980 static void perf_pmu_sched_task(struct task_struct *prev, 2981 struct task_struct *next, 2982 bool sched_in) 2983 { 2984 struct perf_cpu_context *cpuctx; 2985 struct pmu *pmu; 2986 2987 if (prev == next) 2988 return; 2989 2990 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) { 2991 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */ 2992 2993 if (WARN_ON_ONCE(!pmu->sched_task)) 2994 continue; 2995 2996 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 2997 perf_pmu_disable(pmu); 2998 2999 pmu->sched_task(cpuctx->task_ctx, sched_in); 3000 3001 perf_pmu_enable(pmu); 3002 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 3003 } 3004 } 3005 3006 static void perf_event_switch(struct task_struct *task, 3007 struct task_struct *next_prev, bool sched_in); 3008 3009 #define for_each_task_context_nr(ctxn) \ 3010 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++) 3011 3012 /* 3013 * Called from scheduler to remove the events of the current task, 3014 * with interrupts disabled. 3015 * 3016 * We stop each event and update the event value in event->count. 3017 * 3018 * This does not protect us against NMI, but disable() 3019 * sets the disabled bit in the control field of event _before_ 3020 * accessing the event control register. If a NMI hits, then it will 3021 * not restart the event. 3022 */ 3023 void __perf_event_task_sched_out(struct task_struct *task, 3024 struct task_struct *next) 3025 { 3026 int ctxn; 3027 3028 if (__this_cpu_read(perf_sched_cb_usages)) 3029 perf_pmu_sched_task(task, next, false); 3030 3031 if (atomic_read(&nr_switch_events)) 3032 perf_event_switch(task, next, false); 3033 3034 for_each_task_context_nr(ctxn) 3035 perf_event_context_sched_out(task, ctxn, next); 3036 3037 /* 3038 * if cgroup events exist on this CPU, then we need 3039 * to check if we have to switch out PMU state. 3040 * cgroup event are system-wide mode only 3041 */ 3042 if (atomic_read(this_cpu_ptr(&perf_cgroup_events))) 3043 perf_cgroup_sched_out(task, next); 3044 } 3045 3046 /* 3047 * Called with IRQs disabled 3048 */ 3049 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, 3050 enum event_type_t event_type) 3051 { 3052 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type); 3053 } 3054 3055 static void 3056 ctx_pinned_sched_in(struct perf_event_context *ctx, 3057 struct perf_cpu_context *cpuctx) 3058 { 3059 struct perf_event *event; 3060 3061 list_for_each_entry(event, &ctx->pinned_groups, group_entry) { 3062 if (event->state <= PERF_EVENT_STATE_OFF) 3063 continue; 3064 if (!event_filter_match(event)) 3065 continue; 3066 3067 /* may need to reset tstamp_enabled */ 3068 if (is_cgroup_event(event)) 3069 perf_cgroup_mark_enabled(event, ctx); 3070 3071 if (group_can_go_on(event, cpuctx, 1)) 3072 group_sched_in(event, cpuctx, ctx); 3073 3074 /* 3075 * If this pinned group hasn't been scheduled, 3076 * put it in error state. 3077 */ 3078 if (event->state == PERF_EVENT_STATE_INACTIVE) { 3079 update_group_times(event); 3080 event->state = PERF_EVENT_STATE_ERROR; 3081 } 3082 } 3083 } 3084 3085 static void 3086 ctx_flexible_sched_in(struct perf_event_context *ctx, 3087 struct perf_cpu_context *cpuctx) 3088 { 3089 struct perf_event *event; 3090 int can_add_hw = 1; 3091 3092 list_for_each_entry(event, &ctx->flexible_groups, group_entry) { 3093 /* Ignore events in OFF or ERROR state */ 3094 if (event->state <= PERF_EVENT_STATE_OFF) 3095 continue; 3096 /* 3097 * Listen to the 'cpu' scheduling filter constraint 3098 * of events: 3099 */ 3100 if (!event_filter_match(event)) 3101 continue; 3102 3103 /* may need to reset tstamp_enabled */ 3104 if (is_cgroup_event(event)) 3105 perf_cgroup_mark_enabled(event, ctx); 3106 3107 if (group_can_go_on(event, cpuctx, can_add_hw)) { 3108 if (group_sched_in(event, cpuctx, ctx)) 3109 can_add_hw = 0; 3110 } 3111 } 3112 } 3113 3114 static void 3115 ctx_sched_in(struct perf_event_context *ctx, 3116 struct perf_cpu_context *cpuctx, 3117 enum event_type_t event_type, 3118 struct task_struct *task) 3119 { 3120 int is_active = ctx->is_active; 3121 u64 now; 3122 3123 lockdep_assert_held(&ctx->lock); 3124 3125 if (likely(!ctx->nr_events)) 3126 return; 3127 3128 ctx->is_active |= (event_type | EVENT_TIME); 3129 if (ctx->task) { 3130 if (!is_active) 3131 cpuctx->task_ctx = ctx; 3132 else 3133 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 3134 } 3135 3136 is_active ^= ctx->is_active; /* changed bits */ 3137 3138 if (is_active & EVENT_TIME) { 3139 /* start ctx time */ 3140 now = perf_clock(); 3141 ctx->timestamp = now; 3142 perf_cgroup_set_timestamp(task, ctx); 3143 } 3144 3145 /* 3146 * First go through the list and put on any pinned groups 3147 * in order to give them the best chance of going on. 3148 */ 3149 if (is_active & EVENT_PINNED) 3150 ctx_pinned_sched_in(ctx, cpuctx); 3151 3152 /* Then walk through the lower prio flexible groups */ 3153 if (is_active & EVENT_FLEXIBLE) 3154 ctx_flexible_sched_in(ctx, cpuctx); 3155 } 3156 3157 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, 3158 enum event_type_t event_type, 3159 struct task_struct *task) 3160 { 3161 struct perf_event_context *ctx = &cpuctx->ctx; 3162 3163 ctx_sched_in(ctx, cpuctx, event_type, task); 3164 } 3165 3166 static void perf_event_context_sched_in(struct perf_event_context *ctx, 3167 struct task_struct *task) 3168 { 3169 struct perf_cpu_context *cpuctx; 3170 3171 cpuctx = __get_cpu_context(ctx); 3172 if (cpuctx->task_ctx == ctx) 3173 return; 3174 3175 perf_ctx_lock(cpuctx, ctx); 3176 perf_pmu_disable(ctx->pmu); 3177 /* 3178 * We want to keep the following priority order: 3179 * cpu pinned (that don't need to move), task pinned, 3180 * cpu flexible, task flexible. 3181 * 3182 * However, if task's ctx is not carrying any pinned 3183 * events, no need to flip the cpuctx's events around. 3184 */ 3185 if (!list_empty(&ctx->pinned_groups)) 3186 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); 3187 perf_event_sched_in(cpuctx, ctx, task); 3188 perf_pmu_enable(ctx->pmu); 3189 perf_ctx_unlock(cpuctx, ctx); 3190 } 3191 3192 /* 3193 * Called from scheduler to add the events of the current task 3194 * with interrupts disabled. 3195 * 3196 * We restore the event value and then enable it. 3197 * 3198 * This does not protect us against NMI, but enable() 3199 * sets the enabled bit in the control field of event _before_ 3200 * accessing the event control register. If a NMI hits, then it will 3201 * keep the event running. 3202 */ 3203 void __perf_event_task_sched_in(struct task_struct *prev, 3204 struct task_struct *task) 3205 { 3206 struct perf_event_context *ctx; 3207 int ctxn; 3208 3209 /* 3210 * If cgroup events exist on this CPU, then we need to check if we have 3211 * to switch in PMU state; cgroup event are system-wide mode only. 3212 * 3213 * Since cgroup events are CPU events, we must schedule these in before 3214 * we schedule in the task events. 3215 */ 3216 if (atomic_read(this_cpu_ptr(&perf_cgroup_events))) 3217 perf_cgroup_sched_in(prev, task); 3218 3219 for_each_task_context_nr(ctxn) { 3220 ctx = task->perf_event_ctxp[ctxn]; 3221 if (likely(!ctx)) 3222 continue; 3223 3224 perf_event_context_sched_in(ctx, task); 3225 } 3226 3227 if (atomic_read(&nr_switch_events)) 3228 perf_event_switch(task, prev, true); 3229 3230 if (__this_cpu_read(perf_sched_cb_usages)) 3231 perf_pmu_sched_task(prev, task, true); 3232 } 3233 3234 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count) 3235 { 3236 u64 frequency = event->attr.sample_freq; 3237 u64 sec = NSEC_PER_SEC; 3238 u64 divisor, dividend; 3239 3240 int count_fls, nsec_fls, frequency_fls, sec_fls; 3241 3242 count_fls = fls64(count); 3243 nsec_fls = fls64(nsec); 3244 frequency_fls = fls64(frequency); 3245 sec_fls = 30; 3246 3247 /* 3248 * We got @count in @nsec, with a target of sample_freq HZ 3249 * the target period becomes: 3250 * 3251 * @count * 10^9 3252 * period = ------------------- 3253 * @nsec * sample_freq 3254 * 3255 */ 3256 3257 /* 3258 * Reduce accuracy by one bit such that @a and @b converge 3259 * to a similar magnitude. 3260 */ 3261 #define REDUCE_FLS(a, b) \ 3262 do { \ 3263 if (a##_fls > b##_fls) { \ 3264 a >>= 1; \ 3265 a##_fls--; \ 3266 } else { \ 3267 b >>= 1; \ 3268 b##_fls--; \ 3269 } \ 3270 } while (0) 3271 3272 /* 3273 * Reduce accuracy until either term fits in a u64, then proceed with 3274 * the other, so that finally we can do a u64/u64 division. 3275 */ 3276 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) { 3277 REDUCE_FLS(nsec, frequency); 3278 REDUCE_FLS(sec, count); 3279 } 3280 3281 if (count_fls + sec_fls > 64) { 3282 divisor = nsec * frequency; 3283 3284 while (count_fls + sec_fls > 64) { 3285 REDUCE_FLS(count, sec); 3286 divisor >>= 1; 3287 } 3288 3289 dividend = count * sec; 3290 } else { 3291 dividend = count * sec; 3292 3293 while (nsec_fls + frequency_fls > 64) { 3294 REDUCE_FLS(nsec, frequency); 3295 dividend >>= 1; 3296 } 3297 3298 divisor = nsec * frequency; 3299 } 3300 3301 if (!divisor) 3302 return dividend; 3303 3304 return div64_u64(dividend, divisor); 3305 } 3306 3307 static DEFINE_PER_CPU(int, perf_throttled_count); 3308 static DEFINE_PER_CPU(u64, perf_throttled_seq); 3309 3310 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable) 3311 { 3312 struct hw_perf_event *hwc = &event->hw; 3313 s64 period, sample_period; 3314 s64 delta; 3315 3316 period = perf_calculate_period(event, nsec, count); 3317 3318 delta = (s64)(period - hwc->sample_period); 3319 delta = (delta + 7) / 8; /* low pass filter */ 3320 3321 sample_period = hwc->sample_period + delta; 3322 3323 if (!sample_period) 3324 sample_period = 1; 3325 3326 hwc->sample_period = sample_period; 3327 3328 if (local64_read(&hwc->period_left) > 8*sample_period) { 3329 if (disable) 3330 event->pmu->stop(event, PERF_EF_UPDATE); 3331 3332 local64_set(&hwc->period_left, 0); 3333 3334 if (disable) 3335 event->pmu->start(event, PERF_EF_RELOAD); 3336 } 3337 } 3338 3339 /* 3340 * combine freq adjustment with unthrottling to avoid two passes over the 3341 * events. At the same time, make sure, having freq events does not change 3342 * the rate of unthrottling as that would introduce bias. 3343 */ 3344 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx, 3345 int needs_unthr) 3346 { 3347 struct perf_event *event; 3348 struct hw_perf_event *hwc; 3349 u64 now, period = TICK_NSEC; 3350 s64 delta; 3351 3352 /* 3353 * only need to iterate over all events iff: 3354 * - context have events in frequency mode (needs freq adjust) 3355 * - there are events to unthrottle on this cpu 3356 */ 3357 if (!(ctx->nr_freq || needs_unthr)) 3358 return; 3359 3360 raw_spin_lock(&ctx->lock); 3361 perf_pmu_disable(ctx->pmu); 3362 3363 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 3364 if (event->state != PERF_EVENT_STATE_ACTIVE) 3365 continue; 3366 3367 if (!event_filter_match(event)) 3368 continue; 3369 3370 perf_pmu_disable(event->pmu); 3371 3372 hwc = &event->hw; 3373 3374 if (hwc->interrupts == MAX_INTERRUPTS) { 3375 hwc->interrupts = 0; 3376 perf_log_throttle(event, 1); 3377 event->pmu->start(event, 0); 3378 } 3379 3380 if (!event->attr.freq || !event->attr.sample_freq) 3381 goto next; 3382 3383 /* 3384 * stop the event and update event->count 3385 */ 3386 event->pmu->stop(event, PERF_EF_UPDATE); 3387 3388 now = local64_read(&event->count); 3389 delta = now - hwc->freq_count_stamp; 3390 hwc->freq_count_stamp = now; 3391 3392 /* 3393 * restart the event 3394 * reload only if value has changed 3395 * we have stopped the event so tell that 3396 * to perf_adjust_period() to avoid stopping it 3397 * twice. 3398 */ 3399 if (delta > 0) 3400 perf_adjust_period(event, period, delta, false); 3401 3402 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0); 3403 next: 3404 perf_pmu_enable(event->pmu); 3405 } 3406 3407 perf_pmu_enable(ctx->pmu); 3408 raw_spin_unlock(&ctx->lock); 3409 } 3410 3411 /* 3412 * Round-robin a context's events: 3413 */ 3414 static void rotate_ctx(struct perf_event_context *ctx) 3415 { 3416 /* 3417 * Rotate the first entry last of non-pinned groups. Rotation might be 3418 * disabled by the inheritance code. 3419 */ 3420 if (!ctx->rotate_disable) 3421 list_rotate_left(&ctx->flexible_groups); 3422 } 3423 3424 static int perf_rotate_context(struct perf_cpu_context *cpuctx) 3425 { 3426 struct perf_event_context *ctx = NULL; 3427 int rotate = 0; 3428 3429 if (cpuctx->ctx.nr_events) { 3430 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active) 3431 rotate = 1; 3432 } 3433 3434 ctx = cpuctx->task_ctx; 3435 if (ctx && ctx->nr_events) { 3436 if (ctx->nr_events != ctx->nr_active) 3437 rotate = 1; 3438 } 3439 3440 if (!rotate) 3441 goto done; 3442 3443 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 3444 perf_pmu_disable(cpuctx->ctx.pmu); 3445 3446 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); 3447 if (ctx) 3448 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE); 3449 3450 rotate_ctx(&cpuctx->ctx); 3451 if (ctx) 3452 rotate_ctx(ctx); 3453 3454 perf_event_sched_in(cpuctx, ctx, current); 3455 3456 perf_pmu_enable(cpuctx->ctx.pmu); 3457 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 3458 done: 3459 3460 return rotate; 3461 } 3462 3463 void perf_event_task_tick(void) 3464 { 3465 struct list_head *head = this_cpu_ptr(&active_ctx_list); 3466 struct perf_event_context *ctx, *tmp; 3467 int throttled; 3468 3469 WARN_ON(!irqs_disabled()); 3470 3471 __this_cpu_inc(perf_throttled_seq); 3472 throttled = __this_cpu_xchg(perf_throttled_count, 0); 3473 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); 3474 3475 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list) 3476 perf_adjust_freq_unthr_context(ctx, throttled); 3477 } 3478 3479 static int event_enable_on_exec(struct perf_event *event, 3480 struct perf_event_context *ctx) 3481 { 3482 if (!event->attr.enable_on_exec) 3483 return 0; 3484 3485 event->attr.enable_on_exec = 0; 3486 if (event->state >= PERF_EVENT_STATE_INACTIVE) 3487 return 0; 3488 3489 __perf_event_mark_enabled(event); 3490 3491 return 1; 3492 } 3493 3494 /* 3495 * Enable all of a task's events that have been marked enable-on-exec. 3496 * This expects task == current. 3497 */ 3498 static void perf_event_enable_on_exec(int ctxn) 3499 { 3500 struct perf_event_context *ctx, *clone_ctx = NULL; 3501 enum event_type_t event_type = 0; 3502 struct perf_cpu_context *cpuctx; 3503 struct perf_event *event; 3504 unsigned long flags; 3505 int enabled = 0; 3506 3507 local_irq_save(flags); 3508 ctx = current->perf_event_ctxp[ctxn]; 3509 if (!ctx || !ctx->nr_events) 3510 goto out; 3511 3512 cpuctx = __get_cpu_context(ctx); 3513 perf_ctx_lock(cpuctx, ctx); 3514 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 3515 list_for_each_entry(event, &ctx->event_list, event_entry) { 3516 enabled |= event_enable_on_exec(event, ctx); 3517 event_type |= get_event_type(event); 3518 } 3519 3520 /* 3521 * Unclone and reschedule this context if we enabled any event. 3522 */ 3523 if (enabled) { 3524 clone_ctx = unclone_ctx(ctx); 3525 ctx_resched(cpuctx, ctx, event_type); 3526 } else { 3527 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current); 3528 } 3529 perf_ctx_unlock(cpuctx, ctx); 3530 3531 out: 3532 local_irq_restore(flags); 3533 3534 if (clone_ctx) 3535 put_ctx(clone_ctx); 3536 } 3537 3538 struct perf_read_data { 3539 struct perf_event *event; 3540 bool group; 3541 int ret; 3542 }; 3543 3544 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu) 3545 { 3546 u16 local_pkg, event_pkg; 3547 3548 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) { 3549 int local_cpu = smp_processor_id(); 3550 3551 event_pkg = topology_physical_package_id(event_cpu); 3552 local_pkg = topology_physical_package_id(local_cpu); 3553 3554 if (event_pkg == local_pkg) 3555 return local_cpu; 3556 } 3557 3558 return event_cpu; 3559 } 3560 3561 /* 3562 * Cross CPU call to read the hardware event 3563 */ 3564 static void __perf_event_read(void *info) 3565 { 3566 struct perf_read_data *data = info; 3567 struct perf_event *sub, *event = data->event; 3568 struct perf_event_context *ctx = event->ctx; 3569 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 3570 struct pmu *pmu = event->pmu; 3571 3572 /* 3573 * If this is a task context, we need to check whether it is 3574 * the current task context of this cpu. If not it has been 3575 * scheduled out before the smp call arrived. In that case 3576 * event->count would have been updated to a recent sample 3577 * when the event was scheduled out. 3578 */ 3579 if (ctx->task && cpuctx->task_ctx != ctx) 3580 return; 3581 3582 raw_spin_lock(&ctx->lock); 3583 if (ctx->is_active) { 3584 update_context_time(ctx); 3585 update_cgrp_time_from_event(event); 3586 } 3587 3588 update_event_times(event); 3589 if (event->state != PERF_EVENT_STATE_ACTIVE) 3590 goto unlock; 3591 3592 if (!data->group) { 3593 pmu->read(event); 3594 data->ret = 0; 3595 goto unlock; 3596 } 3597 3598 pmu->start_txn(pmu, PERF_PMU_TXN_READ); 3599 3600 pmu->read(event); 3601 3602 list_for_each_entry(sub, &event->sibling_list, group_entry) { 3603 update_event_times(sub); 3604 if (sub->state == PERF_EVENT_STATE_ACTIVE) { 3605 /* 3606 * Use sibling's PMU rather than @event's since 3607 * sibling could be on different (eg: software) PMU. 3608 */ 3609 sub->pmu->read(sub); 3610 } 3611 } 3612 3613 data->ret = pmu->commit_txn(pmu); 3614 3615 unlock: 3616 raw_spin_unlock(&ctx->lock); 3617 } 3618 3619 static inline u64 perf_event_count(struct perf_event *event) 3620 { 3621 if (event->pmu->count) 3622 return event->pmu->count(event); 3623 3624 return __perf_event_count(event); 3625 } 3626 3627 /* 3628 * NMI-safe method to read a local event, that is an event that 3629 * is: 3630 * - either for the current task, or for this CPU 3631 * - does not have inherit set, for inherited task events 3632 * will not be local and we cannot read them atomically 3633 * - must not have a pmu::count method 3634 */ 3635 int perf_event_read_local(struct perf_event *event, u64 *value) 3636 { 3637 unsigned long flags; 3638 int ret = 0; 3639 3640 /* 3641 * Disabling interrupts avoids all counter scheduling (context 3642 * switches, timer based rotation and IPIs). 3643 */ 3644 local_irq_save(flags); 3645 3646 /* 3647 * It must not be an event with inherit set, we cannot read 3648 * all child counters from atomic context. 3649 */ 3650 if (event->attr.inherit) { 3651 ret = -EOPNOTSUPP; 3652 goto out; 3653 } 3654 3655 /* 3656 * It must not have a pmu::count method, those are not 3657 * NMI safe. 3658 */ 3659 if (event->pmu->count) { 3660 ret = -EOPNOTSUPP; 3661 goto out; 3662 } 3663 3664 /* If this is a per-task event, it must be for current */ 3665 if ((event->attach_state & PERF_ATTACH_TASK) && 3666 event->hw.target != current) { 3667 ret = -EINVAL; 3668 goto out; 3669 } 3670 3671 /* If this is a per-CPU event, it must be for this CPU */ 3672 if (!(event->attach_state & PERF_ATTACH_TASK) && 3673 event->cpu != smp_processor_id()) { 3674 ret = -EINVAL; 3675 goto out; 3676 } 3677 3678 /* 3679 * If the event is currently on this CPU, its either a per-task event, 3680 * or local to this CPU. Furthermore it means its ACTIVE (otherwise 3681 * oncpu == -1). 3682 */ 3683 if (event->oncpu == smp_processor_id()) 3684 event->pmu->read(event); 3685 3686 *value = local64_read(&event->count); 3687 out: 3688 local_irq_restore(flags); 3689 3690 return ret; 3691 } 3692 3693 static int perf_event_read(struct perf_event *event, bool group) 3694 { 3695 int event_cpu, ret = 0; 3696 3697 /* 3698 * If event is enabled and currently active on a CPU, update the 3699 * value in the event structure: 3700 */ 3701 if (event->state == PERF_EVENT_STATE_ACTIVE) { 3702 struct perf_read_data data = { 3703 .event = event, 3704 .group = group, 3705 .ret = 0, 3706 }; 3707 3708 event_cpu = READ_ONCE(event->oncpu); 3709 if ((unsigned)event_cpu >= nr_cpu_ids) 3710 return 0; 3711 3712 preempt_disable(); 3713 event_cpu = __perf_event_read_cpu(event, event_cpu); 3714 3715 /* 3716 * Purposely ignore the smp_call_function_single() return 3717 * value. 3718 * 3719 * If event_cpu isn't a valid CPU it means the event got 3720 * scheduled out and that will have updated the event count. 3721 * 3722 * Therefore, either way, we'll have an up-to-date event count 3723 * after this. 3724 */ 3725 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1); 3726 preempt_enable(); 3727 ret = data.ret; 3728 } else if (event->state == PERF_EVENT_STATE_INACTIVE) { 3729 struct perf_event_context *ctx = event->ctx; 3730 unsigned long flags; 3731 3732 raw_spin_lock_irqsave(&ctx->lock, flags); 3733 /* 3734 * may read while context is not active 3735 * (e.g., thread is blocked), in that case 3736 * we cannot update context time 3737 */ 3738 if (ctx->is_active) { 3739 update_context_time(ctx); 3740 update_cgrp_time_from_event(event); 3741 } 3742 if (group) 3743 update_group_times(event); 3744 else 3745 update_event_times(event); 3746 raw_spin_unlock_irqrestore(&ctx->lock, flags); 3747 } 3748 3749 return ret; 3750 } 3751 3752 /* 3753 * Initialize the perf_event context in a task_struct: 3754 */ 3755 static void __perf_event_init_context(struct perf_event_context *ctx) 3756 { 3757 raw_spin_lock_init(&ctx->lock); 3758 mutex_init(&ctx->mutex); 3759 INIT_LIST_HEAD(&ctx->active_ctx_list); 3760 INIT_LIST_HEAD(&ctx->pinned_groups); 3761 INIT_LIST_HEAD(&ctx->flexible_groups); 3762 INIT_LIST_HEAD(&ctx->event_list); 3763 atomic_set(&ctx->refcount, 1); 3764 } 3765 3766 static struct perf_event_context * 3767 alloc_perf_context(struct pmu *pmu, struct task_struct *task) 3768 { 3769 struct perf_event_context *ctx; 3770 3771 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL); 3772 if (!ctx) 3773 return NULL; 3774 3775 __perf_event_init_context(ctx); 3776 if (task) { 3777 ctx->task = task; 3778 get_task_struct(task); 3779 } 3780 ctx->pmu = pmu; 3781 3782 return ctx; 3783 } 3784 3785 static struct task_struct * 3786 find_lively_task_by_vpid(pid_t vpid) 3787 { 3788 struct task_struct *task; 3789 3790 rcu_read_lock(); 3791 if (!vpid) 3792 task = current; 3793 else 3794 task = find_task_by_vpid(vpid); 3795 if (task) 3796 get_task_struct(task); 3797 rcu_read_unlock(); 3798 3799 if (!task) 3800 return ERR_PTR(-ESRCH); 3801 3802 return task; 3803 } 3804 3805 /* 3806 * Returns a matching context with refcount and pincount. 3807 */ 3808 static struct perf_event_context * 3809 find_get_context(struct pmu *pmu, struct task_struct *task, 3810 struct perf_event *event) 3811 { 3812 struct perf_event_context *ctx, *clone_ctx = NULL; 3813 struct perf_cpu_context *cpuctx; 3814 void *task_ctx_data = NULL; 3815 unsigned long flags; 3816 int ctxn, err; 3817 int cpu = event->cpu; 3818 3819 if (!task) { 3820 /* Must be root to operate on a CPU event: */ 3821 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN)) 3822 return ERR_PTR(-EACCES); 3823 3824 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 3825 ctx = &cpuctx->ctx; 3826 get_ctx(ctx); 3827 ++ctx->pin_count; 3828 3829 return ctx; 3830 } 3831 3832 err = -EINVAL; 3833 ctxn = pmu->task_ctx_nr; 3834 if (ctxn < 0) 3835 goto errout; 3836 3837 if (event->attach_state & PERF_ATTACH_TASK_DATA) { 3838 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL); 3839 if (!task_ctx_data) { 3840 err = -ENOMEM; 3841 goto errout; 3842 } 3843 } 3844 3845 retry: 3846 ctx = perf_lock_task_context(task, ctxn, &flags); 3847 if (ctx) { 3848 clone_ctx = unclone_ctx(ctx); 3849 ++ctx->pin_count; 3850 3851 if (task_ctx_data && !ctx->task_ctx_data) { 3852 ctx->task_ctx_data = task_ctx_data; 3853 task_ctx_data = NULL; 3854 } 3855 raw_spin_unlock_irqrestore(&ctx->lock, flags); 3856 3857 if (clone_ctx) 3858 put_ctx(clone_ctx); 3859 } else { 3860 ctx = alloc_perf_context(pmu, task); 3861 err = -ENOMEM; 3862 if (!ctx) 3863 goto errout; 3864 3865 if (task_ctx_data) { 3866 ctx->task_ctx_data = task_ctx_data; 3867 task_ctx_data = NULL; 3868 } 3869 3870 err = 0; 3871 mutex_lock(&task->perf_event_mutex); 3872 /* 3873 * If it has already passed perf_event_exit_task(). 3874 * we must see PF_EXITING, it takes this mutex too. 3875 */ 3876 if (task->flags & PF_EXITING) 3877 err = -ESRCH; 3878 else if (task->perf_event_ctxp[ctxn]) 3879 err = -EAGAIN; 3880 else { 3881 get_ctx(ctx); 3882 ++ctx->pin_count; 3883 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx); 3884 } 3885 mutex_unlock(&task->perf_event_mutex); 3886 3887 if (unlikely(err)) { 3888 put_ctx(ctx); 3889 3890 if (err == -EAGAIN) 3891 goto retry; 3892 goto errout; 3893 } 3894 } 3895 3896 kfree(task_ctx_data); 3897 return ctx; 3898 3899 errout: 3900 kfree(task_ctx_data); 3901 return ERR_PTR(err); 3902 } 3903 3904 static void perf_event_free_filter(struct perf_event *event); 3905 static void perf_event_free_bpf_prog(struct perf_event *event); 3906 3907 static void free_event_rcu(struct rcu_head *head) 3908 { 3909 struct perf_event *event; 3910 3911 event = container_of(head, struct perf_event, rcu_head); 3912 if (event->ns) 3913 put_pid_ns(event->ns); 3914 perf_event_free_filter(event); 3915 kfree(event); 3916 } 3917 3918 static void ring_buffer_attach(struct perf_event *event, 3919 struct ring_buffer *rb); 3920 3921 static void detach_sb_event(struct perf_event *event) 3922 { 3923 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu); 3924 3925 raw_spin_lock(&pel->lock); 3926 list_del_rcu(&event->sb_list); 3927 raw_spin_unlock(&pel->lock); 3928 } 3929 3930 static bool is_sb_event(struct perf_event *event) 3931 { 3932 struct perf_event_attr *attr = &event->attr; 3933 3934 if (event->parent) 3935 return false; 3936 3937 if (event->attach_state & PERF_ATTACH_TASK) 3938 return false; 3939 3940 if (attr->mmap || attr->mmap_data || attr->mmap2 || 3941 attr->comm || attr->comm_exec || 3942 attr->task || 3943 attr->context_switch) 3944 return true; 3945 return false; 3946 } 3947 3948 static void unaccount_pmu_sb_event(struct perf_event *event) 3949 { 3950 if (is_sb_event(event)) 3951 detach_sb_event(event); 3952 } 3953 3954 static void unaccount_event_cpu(struct perf_event *event, int cpu) 3955 { 3956 if (event->parent) 3957 return; 3958 3959 if (is_cgroup_event(event)) 3960 atomic_dec(&per_cpu(perf_cgroup_events, cpu)); 3961 } 3962 3963 #ifdef CONFIG_NO_HZ_FULL 3964 static DEFINE_SPINLOCK(nr_freq_lock); 3965 #endif 3966 3967 static void unaccount_freq_event_nohz(void) 3968 { 3969 #ifdef CONFIG_NO_HZ_FULL 3970 spin_lock(&nr_freq_lock); 3971 if (atomic_dec_and_test(&nr_freq_events)) 3972 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS); 3973 spin_unlock(&nr_freq_lock); 3974 #endif 3975 } 3976 3977 static void unaccount_freq_event(void) 3978 { 3979 if (tick_nohz_full_enabled()) 3980 unaccount_freq_event_nohz(); 3981 else 3982 atomic_dec(&nr_freq_events); 3983 } 3984 3985 static void unaccount_event(struct perf_event *event) 3986 { 3987 bool dec = false; 3988 3989 if (event->parent) 3990 return; 3991 3992 if (event->attach_state & PERF_ATTACH_TASK) 3993 dec = true; 3994 if (event->attr.mmap || event->attr.mmap_data) 3995 atomic_dec(&nr_mmap_events); 3996 if (event->attr.comm) 3997 atomic_dec(&nr_comm_events); 3998 if (event->attr.namespaces) 3999 atomic_dec(&nr_namespaces_events); 4000 if (event->attr.task) 4001 atomic_dec(&nr_task_events); 4002 if (event->attr.freq) 4003 unaccount_freq_event(); 4004 if (event->attr.context_switch) { 4005 dec = true; 4006 atomic_dec(&nr_switch_events); 4007 } 4008 if (is_cgroup_event(event)) 4009 dec = true; 4010 if (has_branch_stack(event)) 4011 dec = true; 4012 4013 if (dec) { 4014 if (!atomic_add_unless(&perf_sched_count, -1, 1)) 4015 schedule_delayed_work(&perf_sched_work, HZ); 4016 } 4017 4018 unaccount_event_cpu(event, event->cpu); 4019 4020 unaccount_pmu_sb_event(event); 4021 } 4022 4023 static void perf_sched_delayed(struct work_struct *work) 4024 { 4025 mutex_lock(&perf_sched_mutex); 4026 if (atomic_dec_and_test(&perf_sched_count)) 4027 static_branch_disable(&perf_sched_events); 4028 mutex_unlock(&perf_sched_mutex); 4029 } 4030 4031 /* 4032 * The following implement mutual exclusion of events on "exclusive" pmus 4033 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled 4034 * at a time, so we disallow creating events that might conflict, namely: 4035 * 4036 * 1) cpu-wide events in the presence of per-task events, 4037 * 2) per-task events in the presence of cpu-wide events, 4038 * 3) two matching events on the same context. 4039 * 4040 * The former two cases are handled in the allocation path (perf_event_alloc(), 4041 * _free_event()), the latter -- before the first perf_install_in_context(). 4042 */ 4043 static int exclusive_event_init(struct perf_event *event) 4044 { 4045 struct pmu *pmu = event->pmu; 4046 4047 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE)) 4048 return 0; 4049 4050 /* 4051 * Prevent co-existence of per-task and cpu-wide events on the 4052 * same exclusive pmu. 4053 * 4054 * Negative pmu::exclusive_cnt means there are cpu-wide 4055 * events on this "exclusive" pmu, positive means there are 4056 * per-task events. 4057 * 4058 * Since this is called in perf_event_alloc() path, event::ctx 4059 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK 4060 * to mean "per-task event", because unlike other attach states it 4061 * never gets cleared. 4062 */ 4063 if (event->attach_state & PERF_ATTACH_TASK) { 4064 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt)) 4065 return -EBUSY; 4066 } else { 4067 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt)) 4068 return -EBUSY; 4069 } 4070 4071 return 0; 4072 } 4073 4074 static void exclusive_event_destroy(struct perf_event *event) 4075 { 4076 struct pmu *pmu = event->pmu; 4077 4078 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE)) 4079 return; 4080 4081 /* see comment in exclusive_event_init() */ 4082 if (event->attach_state & PERF_ATTACH_TASK) 4083 atomic_dec(&pmu->exclusive_cnt); 4084 else 4085 atomic_inc(&pmu->exclusive_cnt); 4086 } 4087 4088 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2) 4089 { 4090 if ((e1->pmu == e2->pmu) && 4091 (e1->cpu == e2->cpu || 4092 e1->cpu == -1 || 4093 e2->cpu == -1)) 4094 return true; 4095 return false; 4096 } 4097 4098 /* Called under the same ctx::mutex as perf_install_in_context() */ 4099 static bool exclusive_event_installable(struct perf_event *event, 4100 struct perf_event_context *ctx) 4101 { 4102 struct perf_event *iter_event; 4103 struct pmu *pmu = event->pmu; 4104 4105 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE)) 4106 return true; 4107 4108 list_for_each_entry(iter_event, &ctx->event_list, event_entry) { 4109 if (exclusive_event_match(iter_event, event)) 4110 return false; 4111 } 4112 4113 return true; 4114 } 4115 4116 static void perf_addr_filters_splice(struct perf_event *event, 4117 struct list_head *head); 4118 4119 static void _free_event(struct perf_event *event) 4120 { 4121 irq_work_sync(&event->pending); 4122 4123 unaccount_event(event); 4124 4125 if (event->rb) { 4126 /* 4127 * Can happen when we close an event with re-directed output. 4128 * 4129 * Since we have a 0 refcount, perf_mmap_close() will skip 4130 * over us; possibly making our ring_buffer_put() the last. 4131 */ 4132 mutex_lock(&event->mmap_mutex); 4133 ring_buffer_attach(event, NULL); 4134 mutex_unlock(&event->mmap_mutex); 4135 } 4136 4137 if (is_cgroup_event(event)) 4138 perf_detach_cgroup(event); 4139 4140 if (!event->parent) { 4141 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) 4142 put_callchain_buffers(); 4143 } 4144 4145 perf_event_free_bpf_prog(event); 4146 perf_addr_filters_splice(event, NULL); 4147 kfree(event->addr_filters_offs); 4148 4149 if (event->destroy) 4150 event->destroy(event); 4151 4152 if (event->ctx) 4153 put_ctx(event->ctx); 4154 4155 exclusive_event_destroy(event); 4156 module_put(event->pmu->module); 4157 4158 call_rcu(&event->rcu_head, free_event_rcu); 4159 } 4160 4161 /* 4162 * Used to free events which have a known refcount of 1, such as in error paths 4163 * where the event isn't exposed yet and inherited events. 4164 */ 4165 static void free_event(struct perf_event *event) 4166 { 4167 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1, 4168 "unexpected event refcount: %ld; ptr=%p\n", 4169 atomic_long_read(&event->refcount), event)) { 4170 /* leak to avoid use-after-free */ 4171 return; 4172 } 4173 4174 _free_event(event); 4175 } 4176 4177 /* 4178 * Remove user event from the owner task. 4179 */ 4180 static void perf_remove_from_owner(struct perf_event *event) 4181 { 4182 struct task_struct *owner; 4183 4184 rcu_read_lock(); 4185 /* 4186 * Matches the smp_store_release() in perf_event_exit_task(). If we 4187 * observe !owner it means the list deletion is complete and we can 4188 * indeed free this event, otherwise we need to serialize on 4189 * owner->perf_event_mutex. 4190 */ 4191 owner = lockless_dereference(event->owner); 4192 if (owner) { 4193 /* 4194 * Since delayed_put_task_struct() also drops the last 4195 * task reference we can safely take a new reference 4196 * while holding the rcu_read_lock(). 4197 */ 4198 get_task_struct(owner); 4199 } 4200 rcu_read_unlock(); 4201 4202 if (owner) { 4203 /* 4204 * If we're here through perf_event_exit_task() we're already 4205 * holding ctx->mutex which would be an inversion wrt. the 4206 * normal lock order. 4207 * 4208 * However we can safely take this lock because its the child 4209 * ctx->mutex. 4210 */ 4211 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING); 4212 4213 /* 4214 * We have to re-check the event->owner field, if it is cleared 4215 * we raced with perf_event_exit_task(), acquiring the mutex 4216 * ensured they're done, and we can proceed with freeing the 4217 * event. 4218 */ 4219 if (event->owner) { 4220 list_del_init(&event->owner_entry); 4221 smp_store_release(&event->owner, NULL); 4222 } 4223 mutex_unlock(&owner->perf_event_mutex); 4224 put_task_struct(owner); 4225 } 4226 } 4227 4228 static void put_event(struct perf_event *event) 4229 { 4230 if (!atomic_long_dec_and_test(&event->refcount)) 4231 return; 4232 4233 _free_event(event); 4234 } 4235 4236 /* 4237 * Kill an event dead; while event:refcount will preserve the event 4238 * object, it will not preserve its functionality. Once the last 'user' 4239 * gives up the object, we'll destroy the thing. 4240 */ 4241 int perf_event_release_kernel(struct perf_event *event) 4242 { 4243 struct perf_event_context *ctx = event->ctx; 4244 struct perf_event *child, *tmp; 4245 4246 /* 4247 * If we got here through err_file: fput(event_file); we will not have 4248 * attached to a context yet. 4249 */ 4250 if (!ctx) { 4251 WARN_ON_ONCE(event->attach_state & 4252 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP)); 4253 goto no_ctx; 4254 } 4255 4256 if (!is_kernel_event(event)) 4257 perf_remove_from_owner(event); 4258 4259 ctx = perf_event_ctx_lock(event); 4260 WARN_ON_ONCE(ctx->parent_ctx); 4261 perf_remove_from_context(event, DETACH_GROUP); 4262 4263 raw_spin_lock_irq(&ctx->lock); 4264 /* 4265 * Mark this event as STATE_DEAD, there is no external reference to it 4266 * anymore. 4267 * 4268 * Anybody acquiring event->child_mutex after the below loop _must_ 4269 * also see this, most importantly inherit_event() which will avoid 4270 * placing more children on the list. 4271 * 4272 * Thus this guarantees that we will in fact observe and kill _ALL_ 4273 * child events. 4274 */ 4275 event->state = PERF_EVENT_STATE_DEAD; 4276 raw_spin_unlock_irq(&ctx->lock); 4277 4278 perf_event_ctx_unlock(event, ctx); 4279 4280 again: 4281 mutex_lock(&event->child_mutex); 4282 list_for_each_entry(child, &event->child_list, child_list) { 4283 4284 /* 4285 * Cannot change, child events are not migrated, see the 4286 * comment with perf_event_ctx_lock_nested(). 4287 */ 4288 ctx = lockless_dereference(child->ctx); 4289 /* 4290 * Since child_mutex nests inside ctx::mutex, we must jump 4291 * through hoops. We start by grabbing a reference on the ctx. 4292 * 4293 * Since the event cannot get freed while we hold the 4294 * child_mutex, the context must also exist and have a !0 4295 * reference count. 4296 */ 4297 get_ctx(ctx); 4298 4299 /* 4300 * Now that we have a ctx ref, we can drop child_mutex, and 4301 * acquire ctx::mutex without fear of it going away. Then we 4302 * can re-acquire child_mutex. 4303 */ 4304 mutex_unlock(&event->child_mutex); 4305 mutex_lock(&ctx->mutex); 4306 mutex_lock(&event->child_mutex); 4307 4308 /* 4309 * Now that we hold ctx::mutex and child_mutex, revalidate our 4310 * state, if child is still the first entry, it didn't get freed 4311 * and we can continue doing so. 4312 */ 4313 tmp = list_first_entry_or_null(&event->child_list, 4314 struct perf_event, child_list); 4315 if (tmp == child) { 4316 perf_remove_from_context(child, DETACH_GROUP); 4317 list_del(&child->child_list); 4318 free_event(child); 4319 /* 4320 * This matches the refcount bump in inherit_event(); 4321 * this can't be the last reference. 4322 */ 4323 put_event(event); 4324 } 4325 4326 mutex_unlock(&event->child_mutex); 4327 mutex_unlock(&ctx->mutex); 4328 put_ctx(ctx); 4329 goto again; 4330 } 4331 mutex_unlock(&event->child_mutex); 4332 4333 no_ctx: 4334 put_event(event); /* Must be the 'last' reference */ 4335 return 0; 4336 } 4337 EXPORT_SYMBOL_GPL(perf_event_release_kernel); 4338 4339 /* 4340 * Called when the last reference to the file is gone. 4341 */ 4342 static int perf_release(struct inode *inode, struct file *file) 4343 { 4344 perf_event_release_kernel(file->private_data); 4345 return 0; 4346 } 4347 4348 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) 4349 { 4350 struct perf_event *child; 4351 u64 total = 0; 4352 4353 *enabled = 0; 4354 *running = 0; 4355 4356 mutex_lock(&event->child_mutex); 4357 4358 (void)perf_event_read(event, false); 4359 total += perf_event_count(event); 4360 4361 *enabled += event->total_time_enabled + 4362 atomic64_read(&event->child_total_time_enabled); 4363 *running += event->total_time_running + 4364 atomic64_read(&event->child_total_time_running); 4365 4366 list_for_each_entry(child, &event->child_list, child_list) { 4367 (void)perf_event_read(child, false); 4368 total += perf_event_count(child); 4369 *enabled += child->total_time_enabled; 4370 *running += child->total_time_running; 4371 } 4372 mutex_unlock(&event->child_mutex); 4373 4374 return total; 4375 } 4376 EXPORT_SYMBOL_GPL(perf_event_read_value); 4377 4378 static int __perf_read_group_add(struct perf_event *leader, 4379 u64 read_format, u64 *values) 4380 { 4381 struct perf_event *sub; 4382 int n = 1; /* skip @nr */ 4383 int ret; 4384 4385 ret = perf_event_read(leader, true); 4386 if (ret) 4387 return ret; 4388 4389 /* 4390 * Since we co-schedule groups, {enabled,running} times of siblings 4391 * will be identical to those of the leader, so we only publish one 4392 * set. 4393 */ 4394 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { 4395 values[n++] += leader->total_time_enabled + 4396 atomic64_read(&leader->child_total_time_enabled); 4397 } 4398 4399 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { 4400 values[n++] += leader->total_time_running + 4401 atomic64_read(&leader->child_total_time_running); 4402 } 4403 4404 /* 4405 * Write {count,id} tuples for every sibling. 4406 */ 4407 values[n++] += perf_event_count(leader); 4408 if (read_format & PERF_FORMAT_ID) 4409 values[n++] = primary_event_id(leader); 4410 4411 list_for_each_entry(sub, &leader->sibling_list, group_entry) { 4412 values[n++] += perf_event_count(sub); 4413 if (read_format & PERF_FORMAT_ID) 4414 values[n++] = primary_event_id(sub); 4415 } 4416 4417 return 0; 4418 } 4419 4420 static int perf_read_group(struct perf_event *event, 4421 u64 read_format, char __user *buf) 4422 { 4423 struct perf_event *leader = event->group_leader, *child; 4424 struct perf_event_context *ctx = leader->ctx; 4425 int ret; 4426 u64 *values; 4427 4428 lockdep_assert_held(&ctx->mutex); 4429 4430 values = kzalloc(event->read_size, GFP_KERNEL); 4431 if (!values) 4432 return -ENOMEM; 4433 4434 values[0] = 1 + leader->nr_siblings; 4435 4436 /* 4437 * By locking the child_mutex of the leader we effectively 4438 * lock the child list of all siblings.. XXX explain how. 4439 */ 4440 mutex_lock(&leader->child_mutex); 4441 4442 ret = __perf_read_group_add(leader, read_format, values); 4443 if (ret) 4444 goto unlock; 4445 4446 list_for_each_entry(child, &leader->child_list, child_list) { 4447 ret = __perf_read_group_add(child, read_format, values); 4448 if (ret) 4449 goto unlock; 4450 } 4451 4452 mutex_unlock(&leader->child_mutex); 4453 4454 ret = event->read_size; 4455 if (copy_to_user(buf, values, event->read_size)) 4456 ret = -EFAULT; 4457 goto out; 4458 4459 unlock: 4460 mutex_unlock(&leader->child_mutex); 4461 out: 4462 kfree(values); 4463 return ret; 4464 } 4465 4466 static int perf_read_one(struct perf_event *event, 4467 u64 read_format, char __user *buf) 4468 { 4469 u64 enabled, running; 4470 u64 values[4]; 4471 int n = 0; 4472 4473 values[n++] = perf_event_read_value(event, &enabled, &running); 4474 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 4475 values[n++] = enabled; 4476 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 4477 values[n++] = running; 4478 if (read_format & PERF_FORMAT_ID) 4479 values[n++] = primary_event_id(event); 4480 4481 if (copy_to_user(buf, values, n * sizeof(u64))) 4482 return -EFAULT; 4483 4484 return n * sizeof(u64); 4485 } 4486 4487 static bool is_event_hup(struct perf_event *event) 4488 { 4489 bool no_children; 4490 4491 if (event->state > PERF_EVENT_STATE_EXIT) 4492 return false; 4493 4494 mutex_lock(&event->child_mutex); 4495 no_children = list_empty(&event->child_list); 4496 mutex_unlock(&event->child_mutex); 4497 return no_children; 4498 } 4499 4500 /* 4501 * Read the performance event - simple non blocking version for now 4502 */ 4503 static ssize_t 4504 __perf_read(struct perf_event *event, char __user *buf, size_t count) 4505 { 4506 u64 read_format = event->attr.read_format; 4507 int ret; 4508 4509 /* 4510 * Return end-of-file for a read on a event that is in 4511 * error state (i.e. because it was pinned but it couldn't be 4512 * scheduled on to the CPU at some point). 4513 */ 4514 if (event->state == PERF_EVENT_STATE_ERROR) 4515 return 0; 4516 4517 if (count < event->read_size) 4518 return -ENOSPC; 4519 4520 WARN_ON_ONCE(event->ctx->parent_ctx); 4521 if (read_format & PERF_FORMAT_GROUP) 4522 ret = perf_read_group(event, read_format, buf); 4523 else 4524 ret = perf_read_one(event, read_format, buf); 4525 4526 return ret; 4527 } 4528 4529 static ssize_t 4530 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 4531 { 4532 struct perf_event *event = file->private_data; 4533 struct perf_event_context *ctx; 4534 int ret; 4535 4536 ctx = perf_event_ctx_lock(event); 4537 ret = __perf_read(event, buf, count); 4538 perf_event_ctx_unlock(event, ctx); 4539 4540 return ret; 4541 } 4542 4543 static unsigned int perf_poll(struct file *file, poll_table *wait) 4544 { 4545 struct perf_event *event = file->private_data; 4546 struct ring_buffer *rb; 4547 unsigned int events = POLLHUP; 4548 4549 poll_wait(file, &event->waitq, wait); 4550 4551 if (is_event_hup(event)) 4552 return events; 4553 4554 /* 4555 * Pin the event->rb by taking event->mmap_mutex; otherwise 4556 * perf_event_set_output() can swizzle our rb and make us miss wakeups. 4557 */ 4558 mutex_lock(&event->mmap_mutex); 4559 rb = event->rb; 4560 if (rb) 4561 events = atomic_xchg(&rb->poll, 0); 4562 mutex_unlock(&event->mmap_mutex); 4563 return events; 4564 } 4565 4566 static void _perf_event_reset(struct perf_event *event) 4567 { 4568 (void)perf_event_read(event, false); 4569 local64_set(&event->count, 0); 4570 perf_event_update_userpage(event); 4571 } 4572 4573 /* 4574 * Holding the top-level event's child_mutex means that any 4575 * descendant process that has inherited this event will block 4576 * in perf_event_exit_event() if it goes to exit, thus satisfying the 4577 * task existence requirements of perf_event_enable/disable. 4578 */ 4579 static void perf_event_for_each_child(struct perf_event *event, 4580 void (*func)(struct perf_event *)) 4581 { 4582 struct perf_event *child; 4583 4584 WARN_ON_ONCE(event->ctx->parent_ctx); 4585 4586 mutex_lock(&event->child_mutex); 4587 func(event); 4588 list_for_each_entry(child, &event->child_list, child_list) 4589 func(child); 4590 mutex_unlock(&event->child_mutex); 4591 } 4592 4593 static void perf_event_for_each(struct perf_event *event, 4594 void (*func)(struct perf_event *)) 4595 { 4596 struct perf_event_context *ctx = event->ctx; 4597 struct perf_event *sibling; 4598 4599 lockdep_assert_held(&ctx->mutex); 4600 4601 event = event->group_leader; 4602 4603 perf_event_for_each_child(event, func); 4604 list_for_each_entry(sibling, &event->sibling_list, group_entry) 4605 perf_event_for_each_child(sibling, func); 4606 } 4607 4608 static void __perf_event_period(struct perf_event *event, 4609 struct perf_cpu_context *cpuctx, 4610 struct perf_event_context *ctx, 4611 void *info) 4612 { 4613 u64 value = *((u64 *)info); 4614 bool active; 4615 4616 if (event->attr.freq) { 4617 event->attr.sample_freq = value; 4618 } else { 4619 event->attr.sample_period = value; 4620 event->hw.sample_period = value; 4621 } 4622 4623 active = (event->state == PERF_EVENT_STATE_ACTIVE); 4624 if (active) { 4625 perf_pmu_disable(ctx->pmu); 4626 /* 4627 * We could be throttled; unthrottle now to avoid the tick 4628 * trying to unthrottle while we already re-started the event. 4629 */ 4630 if (event->hw.interrupts == MAX_INTERRUPTS) { 4631 event->hw.interrupts = 0; 4632 perf_log_throttle(event, 1); 4633 } 4634 event->pmu->stop(event, PERF_EF_UPDATE); 4635 } 4636 4637 local64_set(&event->hw.period_left, 0); 4638 4639 if (active) { 4640 event->pmu->start(event, PERF_EF_RELOAD); 4641 perf_pmu_enable(ctx->pmu); 4642 } 4643 } 4644 4645 static int perf_event_period(struct perf_event *event, u64 __user *arg) 4646 { 4647 u64 value; 4648 4649 if (!is_sampling_event(event)) 4650 return -EINVAL; 4651 4652 if (copy_from_user(&value, arg, sizeof(value))) 4653 return -EFAULT; 4654 4655 if (!value) 4656 return -EINVAL; 4657 4658 if (event->attr.freq && value > sysctl_perf_event_sample_rate) 4659 return -EINVAL; 4660 4661 event_function_call(event, __perf_event_period, &value); 4662 4663 return 0; 4664 } 4665 4666 static const struct file_operations perf_fops; 4667 4668 static inline int perf_fget_light(int fd, struct fd *p) 4669 { 4670 struct fd f = fdget(fd); 4671 if (!f.file) 4672 return -EBADF; 4673 4674 if (f.file->f_op != &perf_fops) { 4675 fdput(f); 4676 return -EBADF; 4677 } 4678 *p = f; 4679 return 0; 4680 } 4681 4682 static int perf_event_set_output(struct perf_event *event, 4683 struct perf_event *output_event); 4684 static int perf_event_set_filter(struct perf_event *event, void __user *arg); 4685 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd); 4686 4687 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg) 4688 { 4689 void (*func)(struct perf_event *); 4690 u32 flags = arg; 4691 4692 switch (cmd) { 4693 case PERF_EVENT_IOC_ENABLE: 4694 func = _perf_event_enable; 4695 break; 4696 case PERF_EVENT_IOC_DISABLE: 4697 func = _perf_event_disable; 4698 break; 4699 case PERF_EVENT_IOC_RESET: 4700 func = _perf_event_reset; 4701 break; 4702 4703 case PERF_EVENT_IOC_REFRESH: 4704 return _perf_event_refresh(event, arg); 4705 4706 case PERF_EVENT_IOC_PERIOD: 4707 return perf_event_period(event, (u64 __user *)arg); 4708 4709 case PERF_EVENT_IOC_ID: 4710 { 4711 u64 id = primary_event_id(event); 4712 4713 if (copy_to_user((void __user *)arg, &id, sizeof(id))) 4714 return -EFAULT; 4715 return 0; 4716 } 4717 4718 case PERF_EVENT_IOC_SET_OUTPUT: 4719 { 4720 int ret; 4721 if (arg != -1) { 4722 struct perf_event *output_event; 4723 struct fd output; 4724 ret = perf_fget_light(arg, &output); 4725 if (ret) 4726 return ret; 4727 output_event = output.file->private_data; 4728 ret = perf_event_set_output(event, output_event); 4729 fdput(output); 4730 } else { 4731 ret = perf_event_set_output(event, NULL); 4732 } 4733 return ret; 4734 } 4735 4736 case PERF_EVENT_IOC_SET_FILTER: 4737 return perf_event_set_filter(event, (void __user *)arg); 4738 4739 case PERF_EVENT_IOC_SET_BPF: 4740 return perf_event_set_bpf_prog(event, arg); 4741 4742 case PERF_EVENT_IOC_PAUSE_OUTPUT: { 4743 struct ring_buffer *rb; 4744 4745 rcu_read_lock(); 4746 rb = rcu_dereference(event->rb); 4747 if (!rb || !rb->nr_pages) { 4748 rcu_read_unlock(); 4749 return -EINVAL; 4750 } 4751 rb_toggle_paused(rb, !!arg); 4752 rcu_read_unlock(); 4753 return 0; 4754 } 4755 default: 4756 return -ENOTTY; 4757 } 4758 4759 if (flags & PERF_IOC_FLAG_GROUP) 4760 perf_event_for_each(event, func); 4761 else 4762 perf_event_for_each_child(event, func); 4763 4764 return 0; 4765 } 4766 4767 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 4768 { 4769 struct perf_event *event = file->private_data; 4770 struct perf_event_context *ctx; 4771 long ret; 4772 4773 ctx = perf_event_ctx_lock(event); 4774 ret = _perf_ioctl(event, cmd, arg); 4775 perf_event_ctx_unlock(event, ctx); 4776 4777 return ret; 4778 } 4779 4780 #ifdef CONFIG_COMPAT 4781 static long perf_compat_ioctl(struct file *file, unsigned int cmd, 4782 unsigned long arg) 4783 { 4784 switch (_IOC_NR(cmd)) { 4785 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER): 4786 case _IOC_NR(PERF_EVENT_IOC_ID): 4787 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */ 4788 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) { 4789 cmd &= ~IOCSIZE_MASK; 4790 cmd |= sizeof(void *) << IOCSIZE_SHIFT; 4791 } 4792 break; 4793 } 4794 return perf_ioctl(file, cmd, arg); 4795 } 4796 #else 4797 # define perf_compat_ioctl NULL 4798 #endif 4799 4800 int perf_event_task_enable(void) 4801 { 4802 struct perf_event_context *ctx; 4803 struct perf_event *event; 4804 4805 mutex_lock(¤t->perf_event_mutex); 4806 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { 4807 ctx = perf_event_ctx_lock(event); 4808 perf_event_for_each_child(event, _perf_event_enable); 4809 perf_event_ctx_unlock(event, ctx); 4810 } 4811 mutex_unlock(¤t->perf_event_mutex); 4812 4813 return 0; 4814 } 4815 4816 int perf_event_task_disable(void) 4817 { 4818 struct perf_event_context *ctx; 4819 struct perf_event *event; 4820 4821 mutex_lock(¤t->perf_event_mutex); 4822 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { 4823 ctx = perf_event_ctx_lock(event); 4824 perf_event_for_each_child(event, _perf_event_disable); 4825 perf_event_ctx_unlock(event, ctx); 4826 } 4827 mutex_unlock(¤t->perf_event_mutex); 4828 4829 return 0; 4830 } 4831 4832 static int perf_event_index(struct perf_event *event) 4833 { 4834 if (event->hw.state & PERF_HES_STOPPED) 4835 return 0; 4836 4837 if (event->state != PERF_EVENT_STATE_ACTIVE) 4838 return 0; 4839 4840 return event->pmu->event_idx(event); 4841 } 4842 4843 static void calc_timer_values(struct perf_event *event, 4844 u64 *now, 4845 u64 *enabled, 4846 u64 *running) 4847 { 4848 u64 ctx_time; 4849 4850 *now = perf_clock(); 4851 ctx_time = event->shadow_ctx_time + *now; 4852 *enabled = ctx_time - event->tstamp_enabled; 4853 *running = ctx_time - event->tstamp_running; 4854 } 4855 4856 static void perf_event_init_userpage(struct perf_event *event) 4857 { 4858 struct perf_event_mmap_page *userpg; 4859 struct ring_buffer *rb; 4860 4861 rcu_read_lock(); 4862 rb = rcu_dereference(event->rb); 4863 if (!rb) 4864 goto unlock; 4865 4866 userpg = rb->user_page; 4867 4868 /* Allow new userspace to detect that bit 0 is deprecated */ 4869 userpg->cap_bit0_is_deprecated = 1; 4870 userpg->size = offsetof(struct perf_event_mmap_page, __reserved); 4871 userpg->data_offset = PAGE_SIZE; 4872 userpg->data_size = perf_data_size(rb); 4873 4874 unlock: 4875 rcu_read_unlock(); 4876 } 4877 4878 void __weak arch_perf_update_userpage( 4879 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now) 4880 { 4881 } 4882 4883 /* 4884 * Callers need to ensure there can be no nesting of this function, otherwise 4885 * the seqlock logic goes bad. We can not serialize this because the arch 4886 * code calls this from NMI context. 4887 */ 4888 void perf_event_update_userpage(struct perf_event *event) 4889 { 4890 struct perf_event_mmap_page *userpg; 4891 struct ring_buffer *rb; 4892 u64 enabled, running, now; 4893 4894 rcu_read_lock(); 4895 rb = rcu_dereference(event->rb); 4896 if (!rb) 4897 goto unlock; 4898 4899 /* 4900 * compute total_time_enabled, total_time_running 4901 * based on snapshot values taken when the event 4902 * was last scheduled in. 4903 * 4904 * we cannot simply called update_context_time() 4905 * because of locking issue as we can be called in 4906 * NMI context 4907 */ 4908 calc_timer_values(event, &now, &enabled, &running); 4909 4910 userpg = rb->user_page; 4911 /* 4912 * Disable preemption so as to not let the corresponding user-space 4913 * spin too long if we get preempted. 4914 */ 4915 preempt_disable(); 4916 ++userpg->lock; 4917 barrier(); 4918 userpg->index = perf_event_index(event); 4919 userpg->offset = perf_event_count(event); 4920 if (userpg->index) 4921 userpg->offset -= local64_read(&event->hw.prev_count); 4922 4923 userpg->time_enabled = enabled + 4924 atomic64_read(&event->child_total_time_enabled); 4925 4926 userpg->time_running = running + 4927 atomic64_read(&event->child_total_time_running); 4928 4929 arch_perf_update_userpage(event, userpg, now); 4930 4931 barrier(); 4932 ++userpg->lock; 4933 preempt_enable(); 4934 unlock: 4935 rcu_read_unlock(); 4936 } 4937 4938 static int perf_mmap_fault(struct vm_fault *vmf) 4939 { 4940 struct perf_event *event = vmf->vma->vm_file->private_data; 4941 struct ring_buffer *rb; 4942 int ret = VM_FAULT_SIGBUS; 4943 4944 if (vmf->flags & FAULT_FLAG_MKWRITE) { 4945 if (vmf->pgoff == 0) 4946 ret = 0; 4947 return ret; 4948 } 4949 4950 rcu_read_lock(); 4951 rb = rcu_dereference(event->rb); 4952 if (!rb) 4953 goto unlock; 4954 4955 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE)) 4956 goto unlock; 4957 4958 vmf->page = perf_mmap_to_page(rb, vmf->pgoff); 4959 if (!vmf->page) 4960 goto unlock; 4961 4962 get_page(vmf->page); 4963 vmf->page->mapping = vmf->vma->vm_file->f_mapping; 4964 vmf->page->index = vmf->pgoff; 4965 4966 ret = 0; 4967 unlock: 4968 rcu_read_unlock(); 4969 4970 return ret; 4971 } 4972 4973 static void ring_buffer_attach(struct perf_event *event, 4974 struct ring_buffer *rb) 4975 { 4976 struct ring_buffer *old_rb = NULL; 4977 unsigned long flags; 4978 4979 if (event->rb) { 4980 /* 4981 * Should be impossible, we set this when removing 4982 * event->rb_entry and wait/clear when adding event->rb_entry. 4983 */ 4984 WARN_ON_ONCE(event->rcu_pending); 4985 4986 old_rb = event->rb; 4987 spin_lock_irqsave(&old_rb->event_lock, flags); 4988 list_del_rcu(&event->rb_entry); 4989 spin_unlock_irqrestore(&old_rb->event_lock, flags); 4990 4991 event->rcu_batches = get_state_synchronize_rcu(); 4992 event->rcu_pending = 1; 4993 } 4994 4995 if (rb) { 4996 if (event->rcu_pending) { 4997 cond_synchronize_rcu(event->rcu_batches); 4998 event->rcu_pending = 0; 4999 } 5000 5001 spin_lock_irqsave(&rb->event_lock, flags); 5002 list_add_rcu(&event->rb_entry, &rb->event_list); 5003 spin_unlock_irqrestore(&rb->event_lock, flags); 5004 } 5005 5006 /* 5007 * Avoid racing with perf_mmap_close(AUX): stop the event 5008 * before swizzling the event::rb pointer; if it's getting 5009 * unmapped, its aux_mmap_count will be 0 and it won't 5010 * restart. See the comment in __perf_pmu_output_stop(). 5011 * 5012 * Data will inevitably be lost when set_output is done in 5013 * mid-air, but then again, whoever does it like this is 5014 * not in for the data anyway. 5015 */ 5016 if (has_aux(event)) 5017 perf_event_stop(event, 0); 5018 5019 rcu_assign_pointer(event->rb, rb); 5020 5021 if (old_rb) { 5022 ring_buffer_put(old_rb); 5023 /* 5024 * Since we detached before setting the new rb, so that we 5025 * could attach the new rb, we could have missed a wakeup. 5026 * Provide it now. 5027 */ 5028 wake_up_all(&event->waitq); 5029 } 5030 } 5031 5032 static void ring_buffer_wakeup(struct perf_event *event) 5033 { 5034 struct ring_buffer *rb; 5035 5036 rcu_read_lock(); 5037 rb = rcu_dereference(event->rb); 5038 if (rb) { 5039 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) 5040 wake_up_all(&event->waitq); 5041 } 5042 rcu_read_unlock(); 5043 } 5044 5045 struct ring_buffer *ring_buffer_get(struct perf_event *event) 5046 { 5047 struct ring_buffer *rb; 5048 5049 rcu_read_lock(); 5050 rb = rcu_dereference(event->rb); 5051 if (rb) { 5052 if (!atomic_inc_not_zero(&rb->refcount)) 5053 rb = NULL; 5054 } 5055 rcu_read_unlock(); 5056 5057 return rb; 5058 } 5059 5060 void ring_buffer_put(struct ring_buffer *rb) 5061 { 5062 if (!atomic_dec_and_test(&rb->refcount)) 5063 return; 5064 5065 WARN_ON_ONCE(!list_empty(&rb->event_list)); 5066 5067 call_rcu(&rb->rcu_head, rb_free_rcu); 5068 } 5069 5070 static void perf_mmap_open(struct vm_area_struct *vma) 5071 { 5072 struct perf_event *event = vma->vm_file->private_data; 5073 5074 atomic_inc(&event->mmap_count); 5075 atomic_inc(&event->rb->mmap_count); 5076 5077 if (vma->vm_pgoff) 5078 atomic_inc(&event->rb->aux_mmap_count); 5079 5080 if (event->pmu->event_mapped) 5081 event->pmu->event_mapped(event); 5082 } 5083 5084 static void perf_pmu_output_stop(struct perf_event *event); 5085 5086 /* 5087 * A buffer can be mmap()ed multiple times; either directly through the same 5088 * event, or through other events by use of perf_event_set_output(). 5089 * 5090 * In order to undo the VM accounting done by perf_mmap() we need to destroy 5091 * the buffer here, where we still have a VM context. This means we need 5092 * to detach all events redirecting to us. 5093 */ 5094 static void perf_mmap_close(struct vm_area_struct *vma) 5095 { 5096 struct perf_event *event = vma->vm_file->private_data; 5097 5098 struct ring_buffer *rb = ring_buffer_get(event); 5099 struct user_struct *mmap_user = rb->mmap_user; 5100 int mmap_locked = rb->mmap_locked; 5101 unsigned long size = perf_data_size(rb); 5102 5103 if (event->pmu->event_unmapped) 5104 event->pmu->event_unmapped(event); 5105 5106 /* 5107 * rb->aux_mmap_count will always drop before rb->mmap_count and 5108 * event->mmap_count, so it is ok to use event->mmap_mutex to 5109 * serialize with perf_mmap here. 5110 */ 5111 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff && 5112 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) { 5113 /* 5114 * Stop all AUX events that are writing to this buffer, 5115 * so that we can free its AUX pages and corresponding PMU 5116 * data. Note that after rb::aux_mmap_count dropped to zero, 5117 * they won't start any more (see perf_aux_output_begin()). 5118 */ 5119 perf_pmu_output_stop(event); 5120 5121 /* now it's safe to free the pages */ 5122 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm); 5123 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked; 5124 5125 /* this has to be the last one */ 5126 rb_free_aux(rb); 5127 WARN_ON_ONCE(atomic_read(&rb->aux_refcount)); 5128 5129 mutex_unlock(&event->mmap_mutex); 5130 } 5131 5132 atomic_dec(&rb->mmap_count); 5133 5134 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) 5135 goto out_put; 5136 5137 ring_buffer_attach(event, NULL); 5138 mutex_unlock(&event->mmap_mutex); 5139 5140 /* If there's still other mmap()s of this buffer, we're done. */ 5141 if (atomic_read(&rb->mmap_count)) 5142 goto out_put; 5143 5144 /* 5145 * No other mmap()s, detach from all other events that might redirect 5146 * into the now unreachable buffer. Somewhat complicated by the 5147 * fact that rb::event_lock otherwise nests inside mmap_mutex. 5148 */ 5149 again: 5150 rcu_read_lock(); 5151 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) { 5152 if (!atomic_long_inc_not_zero(&event->refcount)) { 5153 /* 5154 * This event is en-route to free_event() which will 5155 * detach it and remove it from the list. 5156 */ 5157 continue; 5158 } 5159 rcu_read_unlock(); 5160 5161 mutex_lock(&event->mmap_mutex); 5162 /* 5163 * Check we didn't race with perf_event_set_output() which can 5164 * swizzle the rb from under us while we were waiting to 5165 * acquire mmap_mutex. 5166 * 5167 * If we find a different rb; ignore this event, a next 5168 * iteration will no longer find it on the list. We have to 5169 * still restart the iteration to make sure we're not now 5170 * iterating the wrong list. 5171 */ 5172 if (event->rb == rb) 5173 ring_buffer_attach(event, NULL); 5174 5175 mutex_unlock(&event->mmap_mutex); 5176 put_event(event); 5177 5178 /* 5179 * Restart the iteration; either we're on the wrong list or 5180 * destroyed its integrity by doing a deletion. 5181 */ 5182 goto again; 5183 } 5184 rcu_read_unlock(); 5185 5186 /* 5187 * It could be there's still a few 0-ref events on the list; they'll 5188 * get cleaned up by free_event() -- they'll also still have their 5189 * ref on the rb and will free it whenever they are done with it. 5190 * 5191 * Aside from that, this buffer is 'fully' detached and unmapped, 5192 * undo the VM accounting. 5193 */ 5194 5195 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm); 5196 vma->vm_mm->pinned_vm -= mmap_locked; 5197 free_uid(mmap_user); 5198 5199 out_put: 5200 ring_buffer_put(rb); /* could be last */ 5201 } 5202 5203 static const struct vm_operations_struct perf_mmap_vmops = { 5204 .open = perf_mmap_open, 5205 .close = perf_mmap_close, /* non mergable */ 5206 .fault = perf_mmap_fault, 5207 .page_mkwrite = perf_mmap_fault, 5208 }; 5209 5210 static int perf_mmap(struct file *file, struct vm_area_struct *vma) 5211 { 5212 struct perf_event *event = file->private_data; 5213 unsigned long user_locked, user_lock_limit; 5214 struct user_struct *user = current_user(); 5215 unsigned long locked, lock_limit; 5216 struct ring_buffer *rb = NULL; 5217 unsigned long vma_size; 5218 unsigned long nr_pages; 5219 long user_extra = 0, extra = 0; 5220 int ret = 0, flags = 0; 5221 5222 /* 5223 * Don't allow mmap() of inherited per-task counters. This would 5224 * create a performance issue due to all children writing to the 5225 * same rb. 5226 */ 5227 if (event->cpu == -1 && event->attr.inherit) 5228 return -EINVAL; 5229 5230 if (!(vma->vm_flags & VM_SHARED)) 5231 return -EINVAL; 5232 5233 vma_size = vma->vm_end - vma->vm_start; 5234 5235 if (vma->vm_pgoff == 0) { 5236 nr_pages = (vma_size / PAGE_SIZE) - 1; 5237 } else { 5238 /* 5239 * AUX area mapping: if rb->aux_nr_pages != 0, it's already 5240 * mapped, all subsequent mappings should have the same size 5241 * and offset. Must be above the normal perf buffer. 5242 */ 5243 u64 aux_offset, aux_size; 5244 5245 if (!event->rb) 5246 return -EINVAL; 5247 5248 nr_pages = vma_size / PAGE_SIZE; 5249 5250 mutex_lock(&event->mmap_mutex); 5251 ret = -EINVAL; 5252 5253 rb = event->rb; 5254 if (!rb) 5255 goto aux_unlock; 5256 5257 aux_offset = ACCESS_ONCE(rb->user_page->aux_offset); 5258 aux_size = ACCESS_ONCE(rb->user_page->aux_size); 5259 5260 if (aux_offset < perf_data_size(rb) + PAGE_SIZE) 5261 goto aux_unlock; 5262 5263 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT) 5264 goto aux_unlock; 5265 5266 /* already mapped with a different offset */ 5267 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff) 5268 goto aux_unlock; 5269 5270 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE) 5271 goto aux_unlock; 5272 5273 /* already mapped with a different size */ 5274 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages) 5275 goto aux_unlock; 5276 5277 if (!is_power_of_2(nr_pages)) 5278 goto aux_unlock; 5279 5280 if (!atomic_inc_not_zero(&rb->mmap_count)) 5281 goto aux_unlock; 5282 5283 if (rb_has_aux(rb)) { 5284 atomic_inc(&rb->aux_mmap_count); 5285 ret = 0; 5286 goto unlock; 5287 } 5288 5289 atomic_set(&rb->aux_mmap_count, 1); 5290 user_extra = nr_pages; 5291 5292 goto accounting; 5293 } 5294 5295 /* 5296 * If we have rb pages ensure they're a power-of-two number, so we 5297 * can do bitmasks instead of modulo. 5298 */ 5299 if (nr_pages != 0 && !is_power_of_2(nr_pages)) 5300 return -EINVAL; 5301 5302 if (vma_size != PAGE_SIZE * (1 + nr_pages)) 5303 return -EINVAL; 5304 5305 WARN_ON_ONCE(event->ctx->parent_ctx); 5306 again: 5307 mutex_lock(&event->mmap_mutex); 5308 if (event->rb) { 5309 if (event->rb->nr_pages != nr_pages) { 5310 ret = -EINVAL; 5311 goto unlock; 5312 } 5313 5314 if (!atomic_inc_not_zero(&event->rb->mmap_count)) { 5315 /* 5316 * Raced against perf_mmap_close() through 5317 * perf_event_set_output(). Try again, hope for better 5318 * luck. 5319 */ 5320 mutex_unlock(&event->mmap_mutex); 5321 goto again; 5322 } 5323 5324 goto unlock; 5325 } 5326 5327 user_extra = nr_pages + 1; 5328 5329 accounting: 5330 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10); 5331 5332 /* 5333 * Increase the limit linearly with more CPUs: 5334 */ 5335 user_lock_limit *= num_online_cpus(); 5336 5337 user_locked = atomic_long_read(&user->locked_vm) + user_extra; 5338 5339 if (user_locked > user_lock_limit) 5340 extra = user_locked - user_lock_limit; 5341 5342 lock_limit = rlimit(RLIMIT_MEMLOCK); 5343 lock_limit >>= PAGE_SHIFT; 5344 locked = vma->vm_mm->pinned_vm + extra; 5345 5346 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() && 5347 !capable(CAP_IPC_LOCK)) { 5348 ret = -EPERM; 5349 goto unlock; 5350 } 5351 5352 WARN_ON(!rb && event->rb); 5353 5354 if (vma->vm_flags & VM_WRITE) 5355 flags |= RING_BUFFER_WRITABLE; 5356 5357 if (!rb) { 5358 rb = rb_alloc(nr_pages, 5359 event->attr.watermark ? event->attr.wakeup_watermark : 0, 5360 event->cpu, flags); 5361 5362 if (!rb) { 5363 ret = -ENOMEM; 5364 goto unlock; 5365 } 5366 5367 atomic_set(&rb->mmap_count, 1); 5368 rb->mmap_user = get_current_user(); 5369 rb->mmap_locked = extra; 5370 5371 ring_buffer_attach(event, rb); 5372 5373 perf_event_init_userpage(event); 5374 perf_event_update_userpage(event); 5375 } else { 5376 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages, 5377 event->attr.aux_watermark, flags); 5378 if (!ret) 5379 rb->aux_mmap_locked = extra; 5380 } 5381 5382 unlock: 5383 if (!ret) { 5384 atomic_long_add(user_extra, &user->locked_vm); 5385 vma->vm_mm->pinned_vm += extra; 5386 5387 atomic_inc(&event->mmap_count); 5388 } else if (rb) { 5389 atomic_dec(&rb->mmap_count); 5390 } 5391 aux_unlock: 5392 mutex_unlock(&event->mmap_mutex); 5393 5394 /* 5395 * Since pinned accounting is per vm we cannot allow fork() to copy our 5396 * vma. 5397 */ 5398 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP; 5399 vma->vm_ops = &perf_mmap_vmops; 5400 5401 if (event->pmu->event_mapped) 5402 event->pmu->event_mapped(event); 5403 5404 return ret; 5405 } 5406 5407 static int perf_fasync(int fd, struct file *filp, int on) 5408 { 5409 struct inode *inode = file_inode(filp); 5410 struct perf_event *event = filp->private_data; 5411 int retval; 5412 5413 inode_lock(inode); 5414 retval = fasync_helper(fd, filp, on, &event->fasync); 5415 inode_unlock(inode); 5416 5417 if (retval < 0) 5418 return retval; 5419 5420 return 0; 5421 } 5422 5423 static const struct file_operations perf_fops = { 5424 .llseek = no_llseek, 5425 .release = perf_release, 5426 .read = perf_read, 5427 .poll = perf_poll, 5428 .unlocked_ioctl = perf_ioctl, 5429 .compat_ioctl = perf_compat_ioctl, 5430 .mmap = perf_mmap, 5431 .fasync = perf_fasync, 5432 }; 5433 5434 /* 5435 * Perf event wakeup 5436 * 5437 * If there's data, ensure we set the poll() state and publish everything 5438 * to user-space before waking everybody up. 5439 */ 5440 5441 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event) 5442 { 5443 /* only the parent has fasync state */ 5444 if (event->parent) 5445 event = event->parent; 5446 return &event->fasync; 5447 } 5448 5449 void perf_event_wakeup(struct perf_event *event) 5450 { 5451 ring_buffer_wakeup(event); 5452 5453 if (event->pending_kill) { 5454 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill); 5455 event->pending_kill = 0; 5456 } 5457 } 5458 5459 static void perf_pending_event(struct irq_work *entry) 5460 { 5461 struct perf_event *event = container_of(entry, 5462 struct perf_event, pending); 5463 int rctx; 5464 5465 rctx = perf_swevent_get_recursion_context(); 5466 /* 5467 * If we 'fail' here, that's OK, it means recursion is already disabled 5468 * and we won't recurse 'further'. 5469 */ 5470 5471 if (event->pending_disable) { 5472 event->pending_disable = 0; 5473 perf_event_disable_local(event); 5474 } 5475 5476 if (event->pending_wakeup) { 5477 event->pending_wakeup = 0; 5478 perf_event_wakeup(event); 5479 } 5480 5481 if (rctx >= 0) 5482 perf_swevent_put_recursion_context(rctx); 5483 } 5484 5485 /* 5486 * We assume there is only KVM supporting the callbacks. 5487 * Later on, we might change it to a list if there is 5488 * another virtualization implementation supporting the callbacks. 5489 */ 5490 struct perf_guest_info_callbacks *perf_guest_cbs; 5491 5492 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) 5493 { 5494 perf_guest_cbs = cbs; 5495 return 0; 5496 } 5497 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks); 5498 5499 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) 5500 { 5501 perf_guest_cbs = NULL; 5502 return 0; 5503 } 5504 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks); 5505 5506 static void 5507 perf_output_sample_regs(struct perf_output_handle *handle, 5508 struct pt_regs *regs, u64 mask) 5509 { 5510 int bit; 5511 DECLARE_BITMAP(_mask, 64); 5512 5513 bitmap_from_u64(_mask, mask); 5514 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) { 5515 u64 val; 5516 5517 val = perf_reg_value(regs, bit); 5518 perf_output_put(handle, val); 5519 } 5520 } 5521 5522 static void perf_sample_regs_user(struct perf_regs *regs_user, 5523 struct pt_regs *regs, 5524 struct pt_regs *regs_user_copy) 5525 { 5526 if (user_mode(regs)) { 5527 regs_user->abi = perf_reg_abi(current); 5528 regs_user->regs = regs; 5529 } else if (current->mm) { 5530 perf_get_regs_user(regs_user, regs, regs_user_copy); 5531 } else { 5532 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE; 5533 regs_user->regs = NULL; 5534 } 5535 } 5536 5537 static void perf_sample_regs_intr(struct perf_regs *regs_intr, 5538 struct pt_regs *regs) 5539 { 5540 regs_intr->regs = regs; 5541 regs_intr->abi = perf_reg_abi(current); 5542 } 5543 5544 5545 /* 5546 * Get remaining task size from user stack pointer. 5547 * 5548 * It'd be better to take stack vma map and limit this more 5549 * precisly, but there's no way to get it safely under interrupt, 5550 * so using TASK_SIZE as limit. 5551 */ 5552 static u64 perf_ustack_task_size(struct pt_regs *regs) 5553 { 5554 unsigned long addr = perf_user_stack_pointer(regs); 5555 5556 if (!addr || addr >= TASK_SIZE) 5557 return 0; 5558 5559 return TASK_SIZE - addr; 5560 } 5561 5562 static u16 5563 perf_sample_ustack_size(u16 stack_size, u16 header_size, 5564 struct pt_regs *regs) 5565 { 5566 u64 task_size; 5567 5568 /* No regs, no stack pointer, no dump. */ 5569 if (!regs) 5570 return 0; 5571 5572 /* 5573 * Check if we fit in with the requested stack size into the: 5574 * - TASK_SIZE 5575 * If we don't, we limit the size to the TASK_SIZE. 5576 * 5577 * - remaining sample size 5578 * If we don't, we customize the stack size to 5579 * fit in to the remaining sample size. 5580 */ 5581 5582 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs)); 5583 stack_size = min(stack_size, (u16) task_size); 5584 5585 /* Current header size plus static size and dynamic size. */ 5586 header_size += 2 * sizeof(u64); 5587 5588 /* Do we fit in with the current stack dump size? */ 5589 if ((u16) (header_size + stack_size) < header_size) { 5590 /* 5591 * If we overflow the maximum size for the sample, 5592 * we customize the stack dump size to fit in. 5593 */ 5594 stack_size = USHRT_MAX - header_size - sizeof(u64); 5595 stack_size = round_up(stack_size, sizeof(u64)); 5596 } 5597 5598 return stack_size; 5599 } 5600 5601 static void 5602 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size, 5603 struct pt_regs *regs) 5604 { 5605 /* Case of a kernel thread, nothing to dump */ 5606 if (!regs) { 5607 u64 size = 0; 5608 perf_output_put(handle, size); 5609 } else { 5610 unsigned long sp; 5611 unsigned int rem; 5612 u64 dyn_size; 5613 5614 /* 5615 * We dump: 5616 * static size 5617 * - the size requested by user or the best one we can fit 5618 * in to the sample max size 5619 * data 5620 * - user stack dump data 5621 * dynamic size 5622 * - the actual dumped size 5623 */ 5624 5625 /* Static size. */ 5626 perf_output_put(handle, dump_size); 5627 5628 /* Data. */ 5629 sp = perf_user_stack_pointer(regs); 5630 rem = __output_copy_user(handle, (void *) sp, dump_size); 5631 dyn_size = dump_size - rem; 5632 5633 perf_output_skip(handle, rem); 5634 5635 /* Dynamic size. */ 5636 perf_output_put(handle, dyn_size); 5637 } 5638 } 5639 5640 static void __perf_event_header__init_id(struct perf_event_header *header, 5641 struct perf_sample_data *data, 5642 struct perf_event *event) 5643 { 5644 u64 sample_type = event->attr.sample_type; 5645 5646 data->type = sample_type; 5647 header->size += event->id_header_size; 5648 5649 if (sample_type & PERF_SAMPLE_TID) { 5650 /* namespace issues */ 5651 data->tid_entry.pid = perf_event_pid(event, current); 5652 data->tid_entry.tid = perf_event_tid(event, current); 5653 } 5654 5655 if (sample_type & PERF_SAMPLE_TIME) 5656 data->time = perf_event_clock(event); 5657 5658 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER)) 5659 data->id = primary_event_id(event); 5660 5661 if (sample_type & PERF_SAMPLE_STREAM_ID) 5662 data->stream_id = event->id; 5663 5664 if (sample_type & PERF_SAMPLE_CPU) { 5665 data->cpu_entry.cpu = raw_smp_processor_id(); 5666 data->cpu_entry.reserved = 0; 5667 } 5668 } 5669 5670 void perf_event_header__init_id(struct perf_event_header *header, 5671 struct perf_sample_data *data, 5672 struct perf_event *event) 5673 { 5674 if (event->attr.sample_id_all) 5675 __perf_event_header__init_id(header, data, event); 5676 } 5677 5678 static void __perf_event__output_id_sample(struct perf_output_handle *handle, 5679 struct perf_sample_data *data) 5680 { 5681 u64 sample_type = data->type; 5682 5683 if (sample_type & PERF_SAMPLE_TID) 5684 perf_output_put(handle, data->tid_entry); 5685 5686 if (sample_type & PERF_SAMPLE_TIME) 5687 perf_output_put(handle, data->time); 5688 5689 if (sample_type & PERF_SAMPLE_ID) 5690 perf_output_put(handle, data->id); 5691 5692 if (sample_type & PERF_SAMPLE_STREAM_ID) 5693 perf_output_put(handle, data->stream_id); 5694 5695 if (sample_type & PERF_SAMPLE_CPU) 5696 perf_output_put(handle, data->cpu_entry); 5697 5698 if (sample_type & PERF_SAMPLE_IDENTIFIER) 5699 perf_output_put(handle, data->id); 5700 } 5701 5702 void perf_event__output_id_sample(struct perf_event *event, 5703 struct perf_output_handle *handle, 5704 struct perf_sample_data *sample) 5705 { 5706 if (event->attr.sample_id_all) 5707 __perf_event__output_id_sample(handle, sample); 5708 } 5709 5710 static void perf_output_read_one(struct perf_output_handle *handle, 5711 struct perf_event *event, 5712 u64 enabled, u64 running) 5713 { 5714 u64 read_format = event->attr.read_format; 5715 u64 values[4]; 5716 int n = 0; 5717 5718 values[n++] = perf_event_count(event); 5719 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { 5720 values[n++] = enabled + 5721 atomic64_read(&event->child_total_time_enabled); 5722 } 5723 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { 5724 values[n++] = running + 5725 atomic64_read(&event->child_total_time_running); 5726 } 5727 if (read_format & PERF_FORMAT_ID) 5728 values[n++] = primary_event_id(event); 5729 5730 __output_copy(handle, values, n * sizeof(u64)); 5731 } 5732 5733 static void perf_output_read_group(struct perf_output_handle *handle, 5734 struct perf_event *event, 5735 u64 enabled, u64 running) 5736 { 5737 struct perf_event *leader = event->group_leader, *sub; 5738 u64 read_format = event->attr.read_format; 5739 u64 values[5]; 5740 int n = 0; 5741 5742 values[n++] = 1 + leader->nr_siblings; 5743 5744 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 5745 values[n++] = enabled; 5746 5747 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 5748 values[n++] = running; 5749 5750 if (leader != event) 5751 leader->pmu->read(leader); 5752 5753 values[n++] = perf_event_count(leader); 5754 if (read_format & PERF_FORMAT_ID) 5755 values[n++] = primary_event_id(leader); 5756 5757 __output_copy(handle, values, n * sizeof(u64)); 5758 5759 list_for_each_entry(sub, &leader->sibling_list, group_entry) { 5760 n = 0; 5761 5762 if ((sub != event) && 5763 (sub->state == PERF_EVENT_STATE_ACTIVE)) 5764 sub->pmu->read(sub); 5765 5766 values[n++] = perf_event_count(sub); 5767 if (read_format & PERF_FORMAT_ID) 5768 values[n++] = primary_event_id(sub); 5769 5770 __output_copy(handle, values, n * sizeof(u64)); 5771 } 5772 } 5773 5774 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\ 5775 PERF_FORMAT_TOTAL_TIME_RUNNING) 5776 5777 /* 5778 * XXX PERF_SAMPLE_READ vs inherited events seems difficult. 5779 * 5780 * The problem is that its both hard and excessively expensive to iterate the 5781 * child list, not to mention that its impossible to IPI the children running 5782 * on another CPU, from interrupt/NMI context. 5783 */ 5784 static void perf_output_read(struct perf_output_handle *handle, 5785 struct perf_event *event) 5786 { 5787 u64 enabled = 0, running = 0, now; 5788 u64 read_format = event->attr.read_format; 5789 5790 /* 5791 * compute total_time_enabled, total_time_running 5792 * based on snapshot values taken when the event 5793 * was last scheduled in. 5794 * 5795 * we cannot simply called update_context_time() 5796 * because of locking issue as we are called in 5797 * NMI context 5798 */ 5799 if (read_format & PERF_FORMAT_TOTAL_TIMES) 5800 calc_timer_values(event, &now, &enabled, &running); 5801 5802 if (event->attr.read_format & PERF_FORMAT_GROUP) 5803 perf_output_read_group(handle, event, enabled, running); 5804 else 5805 perf_output_read_one(handle, event, enabled, running); 5806 } 5807 5808 void perf_output_sample(struct perf_output_handle *handle, 5809 struct perf_event_header *header, 5810 struct perf_sample_data *data, 5811 struct perf_event *event) 5812 { 5813 u64 sample_type = data->type; 5814 5815 perf_output_put(handle, *header); 5816 5817 if (sample_type & PERF_SAMPLE_IDENTIFIER) 5818 perf_output_put(handle, data->id); 5819 5820 if (sample_type & PERF_SAMPLE_IP) 5821 perf_output_put(handle, data->ip); 5822 5823 if (sample_type & PERF_SAMPLE_TID) 5824 perf_output_put(handle, data->tid_entry); 5825 5826 if (sample_type & PERF_SAMPLE_TIME) 5827 perf_output_put(handle, data->time); 5828 5829 if (sample_type & PERF_SAMPLE_ADDR) 5830 perf_output_put(handle, data->addr); 5831 5832 if (sample_type & PERF_SAMPLE_ID) 5833 perf_output_put(handle, data->id); 5834 5835 if (sample_type & PERF_SAMPLE_STREAM_ID) 5836 perf_output_put(handle, data->stream_id); 5837 5838 if (sample_type & PERF_SAMPLE_CPU) 5839 perf_output_put(handle, data->cpu_entry); 5840 5841 if (sample_type & PERF_SAMPLE_PERIOD) 5842 perf_output_put(handle, data->period); 5843 5844 if (sample_type & PERF_SAMPLE_READ) 5845 perf_output_read(handle, event); 5846 5847 if (sample_type & PERF_SAMPLE_CALLCHAIN) { 5848 if (data->callchain) { 5849 int size = 1; 5850 5851 if (data->callchain) 5852 size += data->callchain->nr; 5853 5854 size *= sizeof(u64); 5855 5856 __output_copy(handle, data->callchain, size); 5857 } else { 5858 u64 nr = 0; 5859 perf_output_put(handle, nr); 5860 } 5861 } 5862 5863 if (sample_type & PERF_SAMPLE_RAW) { 5864 struct perf_raw_record *raw = data->raw; 5865 5866 if (raw) { 5867 struct perf_raw_frag *frag = &raw->frag; 5868 5869 perf_output_put(handle, raw->size); 5870 do { 5871 if (frag->copy) { 5872 __output_custom(handle, frag->copy, 5873 frag->data, frag->size); 5874 } else { 5875 __output_copy(handle, frag->data, 5876 frag->size); 5877 } 5878 if (perf_raw_frag_last(frag)) 5879 break; 5880 frag = frag->next; 5881 } while (1); 5882 if (frag->pad) 5883 __output_skip(handle, NULL, frag->pad); 5884 } else { 5885 struct { 5886 u32 size; 5887 u32 data; 5888 } raw = { 5889 .size = sizeof(u32), 5890 .data = 0, 5891 }; 5892 perf_output_put(handle, raw); 5893 } 5894 } 5895 5896 if (sample_type & PERF_SAMPLE_BRANCH_STACK) { 5897 if (data->br_stack) { 5898 size_t size; 5899 5900 size = data->br_stack->nr 5901 * sizeof(struct perf_branch_entry); 5902 5903 perf_output_put(handle, data->br_stack->nr); 5904 perf_output_copy(handle, data->br_stack->entries, size); 5905 } else { 5906 /* 5907 * we always store at least the value of nr 5908 */ 5909 u64 nr = 0; 5910 perf_output_put(handle, nr); 5911 } 5912 } 5913 5914 if (sample_type & PERF_SAMPLE_REGS_USER) { 5915 u64 abi = data->regs_user.abi; 5916 5917 /* 5918 * If there are no regs to dump, notice it through 5919 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). 5920 */ 5921 perf_output_put(handle, abi); 5922 5923 if (abi) { 5924 u64 mask = event->attr.sample_regs_user; 5925 perf_output_sample_regs(handle, 5926 data->regs_user.regs, 5927 mask); 5928 } 5929 } 5930 5931 if (sample_type & PERF_SAMPLE_STACK_USER) { 5932 perf_output_sample_ustack(handle, 5933 data->stack_user_size, 5934 data->regs_user.regs); 5935 } 5936 5937 if (sample_type & PERF_SAMPLE_WEIGHT) 5938 perf_output_put(handle, data->weight); 5939 5940 if (sample_type & PERF_SAMPLE_DATA_SRC) 5941 perf_output_put(handle, data->data_src.val); 5942 5943 if (sample_type & PERF_SAMPLE_TRANSACTION) 5944 perf_output_put(handle, data->txn); 5945 5946 if (sample_type & PERF_SAMPLE_REGS_INTR) { 5947 u64 abi = data->regs_intr.abi; 5948 /* 5949 * If there are no regs to dump, notice it through 5950 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). 5951 */ 5952 perf_output_put(handle, abi); 5953 5954 if (abi) { 5955 u64 mask = event->attr.sample_regs_intr; 5956 5957 perf_output_sample_regs(handle, 5958 data->regs_intr.regs, 5959 mask); 5960 } 5961 } 5962 5963 if (!event->attr.watermark) { 5964 int wakeup_events = event->attr.wakeup_events; 5965 5966 if (wakeup_events) { 5967 struct ring_buffer *rb = handle->rb; 5968 int events = local_inc_return(&rb->events); 5969 5970 if (events >= wakeup_events) { 5971 local_sub(wakeup_events, &rb->events); 5972 local_inc(&rb->wakeup); 5973 } 5974 } 5975 } 5976 } 5977 5978 void perf_prepare_sample(struct perf_event_header *header, 5979 struct perf_sample_data *data, 5980 struct perf_event *event, 5981 struct pt_regs *regs) 5982 { 5983 u64 sample_type = event->attr.sample_type; 5984 5985 header->type = PERF_RECORD_SAMPLE; 5986 header->size = sizeof(*header) + event->header_size; 5987 5988 header->misc = 0; 5989 header->misc |= perf_misc_flags(regs); 5990 5991 __perf_event_header__init_id(header, data, event); 5992 5993 if (sample_type & PERF_SAMPLE_IP) 5994 data->ip = perf_instruction_pointer(regs); 5995 5996 if (sample_type & PERF_SAMPLE_CALLCHAIN) { 5997 int size = 1; 5998 5999 data->callchain = perf_callchain(event, regs); 6000 6001 if (data->callchain) 6002 size += data->callchain->nr; 6003 6004 header->size += size * sizeof(u64); 6005 } 6006 6007 if (sample_type & PERF_SAMPLE_RAW) { 6008 struct perf_raw_record *raw = data->raw; 6009 int size; 6010 6011 if (raw) { 6012 struct perf_raw_frag *frag = &raw->frag; 6013 u32 sum = 0; 6014 6015 do { 6016 sum += frag->size; 6017 if (perf_raw_frag_last(frag)) 6018 break; 6019 frag = frag->next; 6020 } while (1); 6021 6022 size = round_up(sum + sizeof(u32), sizeof(u64)); 6023 raw->size = size - sizeof(u32); 6024 frag->pad = raw->size - sum; 6025 } else { 6026 size = sizeof(u64); 6027 } 6028 6029 header->size += size; 6030 } 6031 6032 if (sample_type & PERF_SAMPLE_BRANCH_STACK) { 6033 int size = sizeof(u64); /* nr */ 6034 if (data->br_stack) { 6035 size += data->br_stack->nr 6036 * sizeof(struct perf_branch_entry); 6037 } 6038 header->size += size; 6039 } 6040 6041 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER)) 6042 perf_sample_regs_user(&data->regs_user, regs, 6043 &data->regs_user_copy); 6044 6045 if (sample_type & PERF_SAMPLE_REGS_USER) { 6046 /* regs dump ABI info */ 6047 int size = sizeof(u64); 6048 6049 if (data->regs_user.regs) { 6050 u64 mask = event->attr.sample_regs_user; 6051 size += hweight64(mask) * sizeof(u64); 6052 } 6053 6054 header->size += size; 6055 } 6056 6057 if (sample_type & PERF_SAMPLE_STACK_USER) { 6058 /* 6059 * Either we need PERF_SAMPLE_STACK_USER bit to be allways 6060 * processed as the last one or have additional check added 6061 * in case new sample type is added, because we could eat 6062 * up the rest of the sample size. 6063 */ 6064 u16 stack_size = event->attr.sample_stack_user; 6065 u16 size = sizeof(u64); 6066 6067 stack_size = perf_sample_ustack_size(stack_size, header->size, 6068 data->regs_user.regs); 6069 6070 /* 6071 * If there is something to dump, add space for the dump 6072 * itself and for the field that tells the dynamic size, 6073 * which is how many have been actually dumped. 6074 */ 6075 if (stack_size) 6076 size += sizeof(u64) + stack_size; 6077 6078 data->stack_user_size = stack_size; 6079 header->size += size; 6080 } 6081 6082 if (sample_type & PERF_SAMPLE_REGS_INTR) { 6083 /* regs dump ABI info */ 6084 int size = sizeof(u64); 6085 6086 perf_sample_regs_intr(&data->regs_intr, regs); 6087 6088 if (data->regs_intr.regs) { 6089 u64 mask = event->attr.sample_regs_intr; 6090 6091 size += hweight64(mask) * sizeof(u64); 6092 } 6093 6094 header->size += size; 6095 } 6096 } 6097 6098 static void __always_inline 6099 __perf_event_output(struct perf_event *event, 6100 struct perf_sample_data *data, 6101 struct pt_regs *regs, 6102 int (*output_begin)(struct perf_output_handle *, 6103 struct perf_event *, 6104 unsigned int)) 6105 { 6106 struct perf_output_handle handle; 6107 struct perf_event_header header; 6108 6109 /* protect the callchain buffers */ 6110 rcu_read_lock(); 6111 6112 perf_prepare_sample(&header, data, event, regs); 6113 6114 if (output_begin(&handle, event, header.size)) 6115 goto exit; 6116 6117 perf_output_sample(&handle, &header, data, event); 6118 6119 perf_output_end(&handle); 6120 6121 exit: 6122 rcu_read_unlock(); 6123 } 6124 6125 void 6126 perf_event_output_forward(struct perf_event *event, 6127 struct perf_sample_data *data, 6128 struct pt_regs *regs) 6129 { 6130 __perf_event_output(event, data, regs, perf_output_begin_forward); 6131 } 6132 6133 void 6134 perf_event_output_backward(struct perf_event *event, 6135 struct perf_sample_data *data, 6136 struct pt_regs *regs) 6137 { 6138 __perf_event_output(event, data, regs, perf_output_begin_backward); 6139 } 6140 6141 void 6142 perf_event_output(struct perf_event *event, 6143 struct perf_sample_data *data, 6144 struct pt_regs *regs) 6145 { 6146 __perf_event_output(event, data, regs, perf_output_begin); 6147 } 6148 6149 /* 6150 * read event_id 6151 */ 6152 6153 struct perf_read_event { 6154 struct perf_event_header header; 6155 6156 u32 pid; 6157 u32 tid; 6158 }; 6159 6160 static void 6161 perf_event_read_event(struct perf_event *event, 6162 struct task_struct *task) 6163 { 6164 struct perf_output_handle handle; 6165 struct perf_sample_data sample; 6166 struct perf_read_event read_event = { 6167 .header = { 6168 .type = PERF_RECORD_READ, 6169 .misc = 0, 6170 .size = sizeof(read_event) + event->read_size, 6171 }, 6172 .pid = perf_event_pid(event, task), 6173 .tid = perf_event_tid(event, task), 6174 }; 6175 int ret; 6176 6177 perf_event_header__init_id(&read_event.header, &sample, event); 6178 ret = perf_output_begin(&handle, event, read_event.header.size); 6179 if (ret) 6180 return; 6181 6182 perf_output_put(&handle, read_event); 6183 perf_output_read(&handle, event); 6184 perf_event__output_id_sample(event, &handle, &sample); 6185 6186 perf_output_end(&handle); 6187 } 6188 6189 typedef void (perf_iterate_f)(struct perf_event *event, void *data); 6190 6191 static void 6192 perf_iterate_ctx(struct perf_event_context *ctx, 6193 perf_iterate_f output, 6194 void *data, bool all) 6195 { 6196 struct perf_event *event; 6197 6198 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 6199 if (!all) { 6200 if (event->state < PERF_EVENT_STATE_INACTIVE) 6201 continue; 6202 if (!event_filter_match(event)) 6203 continue; 6204 } 6205 6206 output(event, data); 6207 } 6208 } 6209 6210 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data) 6211 { 6212 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events); 6213 struct perf_event *event; 6214 6215 list_for_each_entry_rcu(event, &pel->list, sb_list) { 6216 /* 6217 * Skip events that are not fully formed yet; ensure that 6218 * if we observe event->ctx, both event and ctx will be 6219 * complete enough. See perf_install_in_context(). 6220 */ 6221 if (!smp_load_acquire(&event->ctx)) 6222 continue; 6223 6224 if (event->state < PERF_EVENT_STATE_INACTIVE) 6225 continue; 6226 if (!event_filter_match(event)) 6227 continue; 6228 output(event, data); 6229 } 6230 } 6231 6232 /* 6233 * Iterate all events that need to receive side-band events. 6234 * 6235 * For new callers; ensure that account_pmu_sb_event() includes 6236 * your event, otherwise it might not get delivered. 6237 */ 6238 static void 6239 perf_iterate_sb(perf_iterate_f output, void *data, 6240 struct perf_event_context *task_ctx) 6241 { 6242 struct perf_event_context *ctx; 6243 int ctxn; 6244 6245 rcu_read_lock(); 6246 preempt_disable(); 6247 6248 /* 6249 * If we have task_ctx != NULL we only notify the task context itself. 6250 * The task_ctx is set only for EXIT events before releasing task 6251 * context. 6252 */ 6253 if (task_ctx) { 6254 perf_iterate_ctx(task_ctx, output, data, false); 6255 goto done; 6256 } 6257 6258 perf_iterate_sb_cpu(output, data); 6259 6260 for_each_task_context_nr(ctxn) { 6261 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); 6262 if (ctx) 6263 perf_iterate_ctx(ctx, output, data, false); 6264 } 6265 done: 6266 preempt_enable(); 6267 rcu_read_unlock(); 6268 } 6269 6270 /* 6271 * Clear all file-based filters at exec, they'll have to be 6272 * re-instated when/if these objects are mmapped again. 6273 */ 6274 static void perf_event_addr_filters_exec(struct perf_event *event, void *data) 6275 { 6276 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 6277 struct perf_addr_filter *filter; 6278 unsigned int restart = 0, count = 0; 6279 unsigned long flags; 6280 6281 if (!has_addr_filter(event)) 6282 return; 6283 6284 raw_spin_lock_irqsave(&ifh->lock, flags); 6285 list_for_each_entry(filter, &ifh->list, entry) { 6286 if (filter->inode) { 6287 event->addr_filters_offs[count] = 0; 6288 restart++; 6289 } 6290 6291 count++; 6292 } 6293 6294 if (restart) 6295 event->addr_filters_gen++; 6296 raw_spin_unlock_irqrestore(&ifh->lock, flags); 6297 6298 if (restart) 6299 perf_event_stop(event, 1); 6300 } 6301 6302 void perf_event_exec(void) 6303 { 6304 struct perf_event_context *ctx; 6305 int ctxn; 6306 6307 rcu_read_lock(); 6308 for_each_task_context_nr(ctxn) { 6309 ctx = current->perf_event_ctxp[ctxn]; 6310 if (!ctx) 6311 continue; 6312 6313 perf_event_enable_on_exec(ctxn); 6314 6315 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL, 6316 true); 6317 } 6318 rcu_read_unlock(); 6319 } 6320 6321 struct remote_output { 6322 struct ring_buffer *rb; 6323 int err; 6324 }; 6325 6326 static void __perf_event_output_stop(struct perf_event *event, void *data) 6327 { 6328 struct perf_event *parent = event->parent; 6329 struct remote_output *ro = data; 6330 struct ring_buffer *rb = ro->rb; 6331 struct stop_event_data sd = { 6332 .event = event, 6333 }; 6334 6335 if (!has_aux(event)) 6336 return; 6337 6338 if (!parent) 6339 parent = event; 6340 6341 /* 6342 * In case of inheritance, it will be the parent that links to the 6343 * ring-buffer, but it will be the child that's actually using it. 6344 * 6345 * We are using event::rb to determine if the event should be stopped, 6346 * however this may race with ring_buffer_attach() (through set_output), 6347 * which will make us skip the event that actually needs to be stopped. 6348 * So ring_buffer_attach() has to stop an aux event before re-assigning 6349 * its rb pointer. 6350 */ 6351 if (rcu_dereference(parent->rb) == rb) 6352 ro->err = __perf_event_stop(&sd); 6353 } 6354 6355 static int __perf_pmu_output_stop(void *info) 6356 { 6357 struct perf_event *event = info; 6358 struct pmu *pmu = event->pmu; 6359 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 6360 struct remote_output ro = { 6361 .rb = event->rb, 6362 }; 6363 6364 rcu_read_lock(); 6365 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false); 6366 if (cpuctx->task_ctx) 6367 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop, 6368 &ro, false); 6369 rcu_read_unlock(); 6370 6371 return ro.err; 6372 } 6373 6374 static void perf_pmu_output_stop(struct perf_event *event) 6375 { 6376 struct perf_event *iter; 6377 int err, cpu; 6378 6379 restart: 6380 rcu_read_lock(); 6381 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) { 6382 /* 6383 * For per-CPU events, we need to make sure that neither they 6384 * nor their children are running; for cpu==-1 events it's 6385 * sufficient to stop the event itself if it's active, since 6386 * it can't have children. 6387 */ 6388 cpu = iter->cpu; 6389 if (cpu == -1) 6390 cpu = READ_ONCE(iter->oncpu); 6391 6392 if (cpu == -1) 6393 continue; 6394 6395 err = cpu_function_call(cpu, __perf_pmu_output_stop, event); 6396 if (err == -EAGAIN) { 6397 rcu_read_unlock(); 6398 goto restart; 6399 } 6400 } 6401 rcu_read_unlock(); 6402 } 6403 6404 /* 6405 * task tracking -- fork/exit 6406 * 6407 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task 6408 */ 6409 6410 struct perf_task_event { 6411 struct task_struct *task; 6412 struct perf_event_context *task_ctx; 6413 6414 struct { 6415 struct perf_event_header header; 6416 6417 u32 pid; 6418 u32 ppid; 6419 u32 tid; 6420 u32 ptid; 6421 u64 time; 6422 } event_id; 6423 }; 6424 6425 static int perf_event_task_match(struct perf_event *event) 6426 { 6427 return event->attr.comm || event->attr.mmap || 6428 event->attr.mmap2 || event->attr.mmap_data || 6429 event->attr.task; 6430 } 6431 6432 static void perf_event_task_output(struct perf_event *event, 6433 void *data) 6434 { 6435 struct perf_task_event *task_event = data; 6436 struct perf_output_handle handle; 6437 struct perf_sample_data sample; 6438 struct task_struct *task = task_event->task; 6439 int ret, size = task_event->event_id.header.size; 6440 6441 if (!perf_event_task_match(event)) 6442 return; 6443 6444 perf_event_header__init_id(&task_event->event_id.header, &sample, event); 6445 6446 ret = perf_output_begin(&handle, event, 6447 task_event->event_id.header.size); 6448 if (ret) 6449 goto out; 6450 6451 task_event->event_id.pid = perf_event_pid(event, task); 6452 task_event->event_id.ppid = perf_event_pid(event, current); 6453 6454 task_event->event_id.tid = perf_event_tid(event, task); 6455 task_event->event_id.ptid = perf_event_tid(event, current); 6456 6457 task_event->event_id.time = perf_event_clock(event); 6458 6459 perf_output_put(&handle, task_event->event_id); 6460 6461 perf_event__output_id_sample(event, &handle, &sample); 6462 6463 perf_output_end(&handle); 6464 out: 6465 task_event->event_id.header.size = size; 6466 } 6467 6468 static void perf_event_task(struct task_struct *task, 6469 struct perf_event_context *task_ctx, 6470 int new) 6471 { 6472 struct perf_task_event task_event; 6473 6474 if (!atomic_read(&nr_comm_events) && 6475 !atomic_read(&nr_mmap_events) && 6476 !atomic_read(&nr_task_events)) 6477 return; 6478 6479 task_event = (struct perf_task_event){ 6480 .task = task, 6481 .task_ctx = task_ctx, 6482 .event_id = { 6483 .header = { 6484 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT, 6485 .misc = 0, 6486 .size = sizeof(task_event.event_id), 6487 }, 6488 /* .pid */ 6489 /* .ppid */ 6490 /* .tid */ 6491 /* .ptid */ 6492 /* .time */ 6493 }, 6494 }; 6495 6496 perf_iterate_sb(perf_event_task_output, 6497 &task_event, 6498 task_ctx); 6499 } 6500 6501 void perf_event_fork(struct task_struct *task) 6502 { 6503 perf_event_task(task, NULL, 1); 6504 perf_event_namespaces(task); 6505 } 6506 6507 /* 6508 * comm tracking 6509 */ 6510 6511 struct perf_comm_event { 6512 struct task_struct *task; 6513 char *comm; 6514 int comm_size; 6515 6516 struct { 6517 struct perf_event_header header; 6518 6519 u32 pid; 6520 u32 tid; 6521 } event_id; 6522 }; 6523 6524 static int perf_event_comm_match(struct perf_event *event) 6525 { 6526 return event->attr.comm; 6527 } 6528 6529 static void perf_event_comm_output(struct perf_event *event, 6530 void *data) 6531 { 6532 struct perf_comm_event *comm_event = data; 6533 struct perf_output_handle handle; 6534 struct perf_sample_data sample; 6535 int size = comm_event->event_id.header.size; 6536 int ret; 6537 6538 if (!perf_event_comm_match(event)) 6539 return; 6540 6541 perf_event_header__init_id(&comm_event->event_id.header, &sample, event); 6542 ret = perf_output_begin(&handle, event, 6543 comm_event->event_id.header.size); 6544 6545 if (ret) 6546 goto out; 6547 6548 comm_event->event_id.pid = perf_event_pid(event, comm_event->task); 6549 comm_event->event_id.tid = perf_event_tid(event, comm_event->task); 6550 6551 perf_output_put(&handle, comm_event->event_id); 6552 __output_copy(&handle, comm_event->comm, 6553 comm_event->comm_size); 6554 6555 perf_event__output_id_sample(event, &handle, &sample); 6556 6557 perf_output_end(&handle); 6558 out: 6559 comm_event->event_id.header.size = size; 6560 } 6561 6562 static void perf_event_comm_event(struct perf_comm_event *comm_event) 6563 { 6564 char comm[TASK_COMM_LEN]; 6565 unsigned int size; 6566 6567 memset(comm, 0, sizeof(comm)); 6568 strlcpy(comm, comm_event->task->comm, sizeof(comm)); 6569 size = ALIGN(strlen(comm)+1, sizeof(u64)); 6570 6571 comm_event->comm = comm; 6572 comm_event->comm_size = size; 6573 6574 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size; 6575 6576 perf_iterate_sb(perf_event_comm_output, 6577 comm_event, 6578 NULL); 6579 } 6580 6581 void perf_event_comm(struct task_struct *task, bool exec) 6582 { 6583 struct perf_comm_event comm_event; 6584 6585 if (!atomic_read(&nr_comm_events)) 6586 return; 6587 6588 comm_event = (struct perf_comm_event){ 6589 .task = task, 6590 /* .comm */ 6591 /* .comm_size */ 6592 .event_id = { 6593 .header = { 6594 .type = PERF_RECORD_COMM, 6595 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0, 6596 /* .size */ 6597 }, 6598 /* .pid */ 6599 /* .tid */ 6600 }, 6601 }; 6602 6603 perf_event_comm_event(&comm_event); 6604 } 6605 6606 /* 6607 * namespaces tracking 6608 */ 6609 6610 struct perf_namespaces_event { 6611 struct task_struct *task; 6612 6613 struct { 6614 struct perf_event_header header; 6615 6616 u32 pid; 6617 u32 tid; 6618 u64 nr_namespaces; 6619 struct perf_ns_link_info link_info[NR_NAMESPACES]; 6620 } event_id; 6621 }; 6622 6623 static int perf_event_namespaces_match(struct perf_event *event) 6624 { 6625 return event->attr.namespaces; 6626 } 6627 6628 static void perf_event_namespaces_output(struct perf_event *event, 6629 void *data) 6630 { 6631 struct perf_namespaces_event *namespaces_event = data; 6632 struct perf_output_handle handle; 6633 struct perf_sample_data sample; 6634 int ret; 6635 6636 if (!perf_event_namespaces_match(event)) 6637 return; 6638 6639 perf_event_header__init_id(&namespaces_event->event_id.header, 6640 &sample, event); 6641 ret = perf_output_begin(&handle, event, 6642 namespaces_event->event_id.header.size); 6643 if (ret) 6644 return; 6645 6646 namespaces_event->event_id.pid = perf_event_pid(event, 6647 namespaces_event->task); 6648 namespaces_event->event_id.tid = perf_event_tid(event, 6649 namespaces_event->task); 6650 6651 perf_output_put(&handle, namespaces_event->event_id); 6652 6653 perf_event__output_id_sample(event, &handle, &sample); 6654 6655 perf_output_end(&handle); 6656 } 6657 6658 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info, 6659 struct task_struct *task, 6660 const struct proc_ns_operations *ns_ops) 6661 { 6662 struct path ns_path; 6663 struct inode *ns_inode; 6664 void *error; 6665 6666 error = ns_get_path(&ns_path, task, ns_ops); 6667 if (!error) { 6668 ns_inode = ns_path.dentry->d_inode; 6669 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev); 6670 ns_link_info->ino = ns_inode->i_ino; 6671 } 6672 } 6673 6674 void perf_event_namespaces(struct task_struct *task) 6675 { 6676 struct perf_namespaces_event namespaces_event; 6677 struct perf_ns_link_info *ns_link_info; 6678 6679 if (!atomic_read(&nr_namespaces_events)) 6680 return; 6681 6682 namespaces_event = (struct perf_namespaces_event){ 6683 .task = task, 6684 .event_id = { 6685 .header = { 6686 .type = PERF_RECORD_NAMESPACES, 6687 .misc = 0, 6688 .size = sizeof(namespaces_event.event_id), 6689 }, 6690 /* .pid */ 6691 /* .tid */ 6692 .nr_namespaces = NR_NAMESPACES, 6693 /* .link_info[NR_NAMESPACES] */ 6694 }, 6695 }; 6696 6697 ns_link_info = namespaces_event.event_id.link_info; 6698 6699 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX], 6700 task, &mntns_operations); 6701 6702 #ifdef CONFIG_USER_NS 6703 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX], 6704 task, &userns_operations); 6705 #endif 6706 #ifdef CONFIG_NET_NS 6707 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX], 6708 task, &netns_operations); 6709 #endif 6710 #ifdef CONFIG_UTS_NS 6711 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX], 6712 task, &utsns_operations); 6713 #endif 6714 #ifdef CONFIG_IPC_NS 6715 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX], 6716 task, &ipcns_operations); 6717 #endif 6718 #ifdef CONFIG_PID_NS 6719 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX], 6720 task, &pidns_operations); 6721 #endif 6722 #ifdef CONFIG_CGROUPS 6723 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX], 6724 task, &cgroupns_operations); 6725 #endif 6726 6727 perf_iterate_sb(perf_event_namespaces_output, 6728 &namespaces_event, 6729 NULL); 6730 } 6731 6732 /* 6733 * mmap tracking 6734 */ 6735 6736 struct perf_mmap_event { 6737 struct vm_area_struct *vma; 6738 6739 const char *file_name; 6740 int file_size; 6741 int maj, min; 6742 u64 ino; 6743 u64 ino_generation; 6744 u32 prot, flags; 6745 6746 struct { 6747 struct perf_event_header header; 6748 6749 u32 pid; 6750 u32 tid; 6751 u64 start; 6752 u64 len; 6753 u64 pgoff; 6754 } event_id; 6755 }; 6756 6757 static int perf_event_mmap_match(struct perf_event *event, 6758 void *data) 6759 { 6760 struct perf_mmap_event *mmap_event = data; 6761 struct vm_area_struct *vma = mmap_event->vma; 6762 int executable = vma->vm_flags & VM_EXEC; 6763 6764 return (!executable && event->attr.mmap_data) || 6765 (executable && (event->attr.mmap || event->attr.mmap2)); 6766 } 6767 6768 static void perf_event_mmap_output(struct perf_event *event, 6769 void *data) 6770 { 6771 struct perf_mmap_event *mmap_event = data; 6772 struct perf_output_handle handle; 6773 struct perf_sample_data sample; 6774 int size = mmap_event->event_id.header.size; 6775 int ret; 6776 6777 if (!perf_event_mmap_match(event, data)) 6778 return; 6779 6780 if (event->attr.mmap2) { 6781 mmap_event->event_id.header.type = PERF_RECORD_MMAP2; 6782 mmap_event->event_id.header.size += sizeof(mmap_event->maj); 6783 mmap_event->event_id.header.size += sizeof(mmap_event->min); 6784 mmap_event->event_id.header.size += sizeof(mmap_event->ino); 6785 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation); 6786 mmap_event->event_id.header.size += sizeof(mmap_event->prot); 6787 mmap_event->event_id.header.size += sizeof(mmap_event->flags); 6788 } 6789 6790 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event); 6791 ret = perf_output_begin(&handle, event, 6792 mmap_event->event_id.header.size); 6793 if (ret) 6794 goto out; 6795 6796 mmap_event->event_id.pid = perf_event_pid(event, current); 6797 mmap_event->event_id.tid = perf_event_tid(event, current); 6798 6799 perf_output_put(&handle, mmap_event->event_id); 6800 6801 if (event->attr.mmap2) { 6802 perf_output_put(&handle, mmap_event->maj); 6803 perf_output_put(&handle, mmap_event->min); 6804 perf_output_put(&handle, mmap_event->ino); 6805 perf_output_put(&handle, mmap_event->ino_generation); 6806 perf_output_put(&handle, mmap_event->prot); 6807 perf_output_put(&handle, mmap_event->flags); 6808 } 6809 6810 __output_copy(&handle, mmap_event->file_name, 6811 mmap_event->file_size); 6812 6813 perf_event__output_id_sample(event, &handle, &sample); 6814 6815 perf_output_end(&handle); 6816 out: 6817 mmap_event->event_id.header.size = size; 6818 } 6819 6820 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) 6821 { 6822 struct vm_area_struct *vma = mmap_event->vma; 6823 struct file *file = vma->vm_file; 6824 int maj = 0, min = 0; 6825 u64 ino = 0, gen = 0; 6826 u32 prot = 0, flags = 0; 6827 unsigned int size; 6828 char tmp[16]; 6829 char *buf = NULL; 6830 char *name; 6831 6832 if (vma->vm_flags & VM_READ) 6833 prot |= PROT_READ; 6834 if (vma->vm_flags & VM_WRITE) 6835 prot |= PROT_WRITE; 6836 if (vma->vm_flags & VM_EXEC) 6837 prot |= PROT_EXEC; 6838 6839 if (vma->vm_flags & VM_MAYSHARE) 6840 flags = MAP_SHARED; 6841 else 6842 flags = MAP_PRIVATE; 6843 6844 if (vma->vm_flags & VM_DENYWRITE) 6845 flags |= MAP_DENYWRITE; 6846 if (vma->vm_flags & VM_MAYEXEC) 6847 flags |= MAP_EXECUTABLE; 6848 if (vma->vm_flags & VM_LOCKED) 6849 flags |= MAP_LOCKED; 6850 if (vma->vm_flags & VM_HUGETLB) 6851 flags |= MAP_HUGETLB; 6852 6853 if (file) { 6854 struct inode *inode; 6855 dev_t dev; 6856 6857 buf = kmalloc(PATH_MAX, GFP_KERNEL); 6858 if (!buf) { 6859 name = "//enomem"; 6860 goto cpy_name; 6861 } 6862 /* 6863 * d_path() works from the end of the rb backwards, so we 6864 * need to add enough zero bytes after the string to handle 6865 * the 64bit alignment we do later. 6866 */ 6867 name = file_path(file, buf, PATH_MAX - sizeof(u64)); 6868 if (IS_ERR(name)) { 6869 name = "//toolong"; 6870 goto cpy_name; 6871 } 6872 inode = file_inode(vma->vm_file); 6873 dev = inode->i_sb->s_dev; 6874 ino = inode->i_ino; 6875 gen = inode->i_generation; 6876 maj = MAJOR(dev); 6877 min = MINOR(dev); 6878 6879 goto got_name; 6880 } else { 6881 if (vma->vm_ops && vma->vm_ops->name) { 6882 name = (char *) vma->vm_ops->name(vma); 6883 if (name) 6884 goto cpy_name; 6885 } 6886 6887 name = (char *)arch_vma_name(vma); 6888 if (name) 6889 goto cpy_name; 6890 6891 if (vma->vm_start <= vma->vm_mm->start_brk && 6892 vma->vm_end >= vma->vm_mm->brk) { 6893 name = "[heap]"; 6894 goto cpy_name; 6895 } 6896 if (vma->vm_start <= vma->vm_mm->start_stack && 6897 vma->vm_end >= vma->vm_mm->start_stack) { 6898 name = "[stack]"; 6899 goto cpy_name; 6900 } 6901 6902 name = "//anon"; 6903 goto cpy_name; 6904 } 6905 6906 cpy_name: 6907 strlcpy(tmp, name, sizeof(tmp)); 6908 name = tmp; 6909 got_name: 6910 /* 6911 * Since our buffer works in 8 byte units we need to align our string 6912 * size to a multiple of 8. However, we must guarantee the tail end is 6913 * zero'd out to avoid leaking random bits to userspace. 6914 */ 6915 size = strlen(name)+1; 6916 while (!IS_ALIGNED(size, sizeof(u64))) 6917 name[size++] = '\0'; 6918 6919 mmap_event->file_name = name; 6920 mmap_event->file_size = size; 6921 mmap_event->maj = maj; 6922 mmap_event->min = min; 6923 mmap_event->ino = ino; 6924 mmap_event->ino_generation = gen; 6925 mmap_event->prot = prot; 6926 mmap_event->flags = flags; 6927 6928 if (!(vma->vm_flags & VM_EXEC)) 6929 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA; 6930 6931 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size; 6932 6933 perf_iterate_sb(perf_event_mmap_output, 6934 mmap_event, 6935 NULL); 6936 6937 kfree(buf); 6938 } 6939 6940 /* 6941 * Check whether inode and address range match filter criteria. 6942 */ 6943 static bool perf_addr_filter_match(struct perf_addr_filter *filter, 6944 struct file *file, unsigned long offset, 6945 unsigned long size) 6946 { 6947 if (filter->inode != file_inode(file)) 6948 return false; 6949 6950 if (filter->offset > offset + size) 6951 return false; 6952 6953 if (filter->offset + filter->size < offset) 6954 return false; 6955 6956 return true; 6957 } 6958 6959 static void __perf_addr_filters_adjust(struct perf_event *event, void *data) 6960 { 6961 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 6962 struct vm_area_struct *vma = data; 6963 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags; 6964 struct file *file = vma->vm_file; 6965 struct perf_addr_filter *filter; 6966 unsigned int restart = 0, count = 0; 6967 6968 if (!has_addr_filter(event)) 6969 return; 6970 6971 if (!file) 6972 return; 6973 6974 raw_spin_lock_irqsave(&ifh->lock, flags); 6975 list_for_each_entry(filter, &ifh->list, entry) { 6976 if (perf_addr_filter_match(filter, file, off, 6977 vma->vm_end - vma->vm_start)) { 6978 event->addr_filters_offs[count] = vma->vm_start; 6979 restart++; 6980 } 6981 6982 count++; 6983 } 6984 6985 if (restart) 6986 event->addr_filters_gen++; 6987 raw_spin_unlock_irqrestore(&ifh->lock, flags); 6988 6989 if (restart) 6990 perf_event_stop(event, 1); 6991 } 6992 6993 /* 6994 * Adjust all task's events' filters to the new vma 6995 */ 6996 static void perf_addr_filters_adjust(struct vm_area_struct *vma) 6997 { 6998 struct perf_event_context *ctx; 6999 int ctxn; 7000 7001 /* 7002 * Data tracing isn't supported yet and as such there is no need 7003 * to keep track of anything that isn't related to executable code: 7004 */ 7005 if (!(vma->vm_flags & VM_EXEC)) 7006 return; 7007 7008 rcu_read_lock(); 7009 for_each_task_context_nr(ctxn) { 7010 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); 7011 if (!ctx) 7012 continue; 7013 7014 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true); 7015 } 7016 rcu_read_unlock(); 7017 } 7018 7019 void perf_event_mmap(struct vm_area_struct *vma) 7020 { 7021 struct perf_mmap_event mmap_event; 7022 7023 if (!atomic_read(&nr_mmap_events)) 7024 return; 7025 7026 mmap_event = (struct perf_mmap_event){ 7027 .vma = vma, 7028 /* .file_name */ 7029 /* .file_size */ 7030 .event_id = { 7031 .header = { 7032 .type = PERF_RECORD_MMAP, 7033 .misc = PERF_RECORD_MISC_USER, 7034 /* .size */ 7035 }, 7036 /* .pid */ 7037 /* .tid */ 7038 .start = vma->vm_start, 7039 .len = vma->vm_end - vma->vm_start, 7040 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT, 7041 }, 7042 /* .maj (attr_mmap2 only) */ 7043 /* .min (attr_mmap2 only) */ 7044 /* .ino (attr_mmap2 only) */ 7045 /* .ino_generation (attr_mmap2 only) */ 7046 /* .prot (attr_mmap2 only) */ 7047 /* .flags (attr_mmap2 only) */ 7048 }; 7049 7050 perf_addr_filters_adjust(vma); 7051 perf_event_mmap_event(&mmap_event); 7052 } 7053 7054 void perf_event_aux_event(struct perf_event *event, unsigned long head, 7055 unsigned long size, u64 flags) 7056 { 7057 struct perf_output_handle handle; 7058 struct perf_sample_data sample; 7059 struct perf_aux_event { 7060 struct perf_event_header header; 7061 u64 offset; 7062 u64 size; 7063 u64 flags; 7064 } rec = { 7065 .header = { 7066 .type = PERF_RECORD_AUX, 7067 .misc = 0, 7068 .size = sizeof(rec), 7069 }, 7070 .offset = head, 7071 .size = size, 7072 .flags = flags, 7073 }; 7074 int ret; 7075 7076 perf_event_header__init_id(&rec.header, &sample, event); 7077 ret = perf_output_begin(&handle, event, rec.header.size); 7078 7079 if (ret) 7080 return; 7081 7082 perf_output_put(&handle, rec); 7083 perf_event__output_id_sample(event, &handle, &sample); 7084 7085 perf_output_end(&handle); 7086 } 7087 7088 /* 7089 * Lost/dropped samples logging 7090 */ 7091 void perf_log_lost_samples(struct perf_event *event, u64 lost) 7092 { 7093 struct perf_output_handle handle; 7094 struct perf_sample_data sample; 7095 int ret; 7096 7097 struct { 7098 struct perf_event_header header; 7099 u64 lost; 7100 } lost_samples_event = { 7101 .header = { 7102 .type = PERF_RECORD_LOST_SAMPLES, 7103 .misc = 0, 7104 .size = sizeof(lost_samples_event), 7105 }, 7106 .lost = lost, 7107 }; 7108 7109 perf_event_header__init_id(&lost_samples_event.header, &sample, event); 7110 7111 ret = perf_output_begin(&handle, event, 7112 lost_samples_event.header.size); 7113 if (ret) 7114 return; 7115 7116 perf_output_put(&handle, lost_samples_event); 7117 perf_event__output_id_sample(event, &handle, &sample); 7118 perf_output_end(&handle); 7119 } 7120 7121 /* 7122 * context_switch tracking 7123 */ 7124 7125 struct perf_switch_event { 7126 struct task_struct *task; 7127 struct task_struct *next_prev; 7128 7129 struct { 7130 struct perf_event_header header; 7131 u32 next_prev_pid; 7132 u32 next_prev_tid; 7133 } event_id; 7134 }; 7135 7136 static int perf_event_switch_match(struct perf_event *event) 7137 { 7138 return event->attr.context_switch; 7139 } 7140 7141 static void perf_event_switch_output(struct perf_event *event, void *data) 7142 { 7143 struct perf_switch_event *se = data; 7144 struct perf_output_handle handle; 7145 struct perf_sample_data sample; 7146 int ret; 7147 7148 if (!perf_event_switch_match(event)) 7149 return; 7150 7151 /* Only CPU-wide events are allowed to see next/prev pid/tid */ 7152 if (event->ctx->task) { 7153 se->event_id.header.type = PERF_RECORD_SWITCH; 7154 se->event_id.header.size = sizeof(se->event_id.header); 7155 } else { 7156 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE; 7157 se->event_id.header.size = sizeof(se->event_id); 7158 se->event_id.next_prev_pid = 7159 perf_event_pid(event, se->next_prev); 7160 se->event_id.next_prev_tid = 7161 perf_event_tid(event, se->next_prev); 7162 } 7163 7164 perf_event_header__init_id(&se->event_id.header, &sample, event); 7165 7166 ret = perf_output_begin(&handle, event, se->event_id.header.size); 7167 if (ret) 7168 return; 7169 7170 if (event->ctx->task) 7171 perf_output_put(&handle, se->event_id.header); 7172 else 7173 perf_output_put(&handle, se->event_id); 7174 7175 perf_event__output_id_sample(event, &handle, &sample); 7176 7177 perf_output_end(&handle); 7178 } 7179 7180 static void perf_event_switch(struct task_struct *task, 7181 struct task_struct *next_prev, bool sched_in) 7182 { 7183 struct perf_switch_event switch_event; 7184 7185 /* N.B. caller checks nr_switch_events != 0 */ 7186 7187 switch_event = (struct perf_switch_event){ 7188 .task = task, 7189 .next_prev = next_prev, 7190 .event_id = { 7191 .header = { 7192 /* .type */ 7193 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT, 7194 /* .size */ 7195 }, 7196 /* .next_prev_pid */ 7197 /* .next_prev_tid */ 7198 }, 7199 }; 7200 7201 perf_iterate_sb(perf_event_switch_output, 7202 &switch_event, 7203 NULL); 7204 } 7205 7206 /* 7207 * IRQ throttle logging 7208 */ 7209 7210 static void perf_log_throttle(struct perf_event *event, int enable) 7211 { 7212 struct perf_output_handle handle; 7213 struct perf_sample_data sample; 7214 int ret; 7215 7216 struct { 7217 struct perf_event_header header; 7218 u64 time; 7219 u64 id; 7220 u64 stream_id; 7221 } throttle_event = { 7222 .header = { 7223 .type = PERF_RECORD_THROTTLE, 7224 .misc = 0, 7225 .size = sizeof(throttle_event), 7226 }, 7227 .time = perf_event_clock(event), 7228 .id = primary_event_id(event), 7229 .stream_id = event->id, 7230 }; 7231 7232 if (enable) 7233 throttle_event.header.type = PERF_RECORD_UNTHROTTLE; 7234 7235 perf_event_header__init_id(&throttle_event.header, &sample, event); 7236 7237 ret = perf_output_begin(&handle, event, 7238 throttle_event.header.size); 7239 if (ret) 7240 return; 7241 7242 perf_output_put(&handle, throttle_event); 7243 perf_event__output_id_sample(event, &handle, &sample); 7244 perf_output_end(&handle); 7245 } 7246 7247 static void perf_log_itrace_start(struct perf_event *event) 7248 { 7249 struct perf_output_handle handle; 7250 struct perf_sample_data sample; 7251 struct perf_aux_event { 7252 struct perf_event_header header; 7253 u32 pid; 7254 u32 tid; 7255 } rec; 7256 int ret; 7257 7258 if (event->parent) 7259 event = event->parent; 7260 7261 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) || 7262 event->hw.itrace_started) 7263 return; 7264 7265 rec.header.type = PERF_RECORD_ITRACE_START; 7266 rec.header.misc = 0; 7267 rec.header.size = sizeof(rec); 7268 rec.pid = perf_event_pid(event, current); 7269 rec.tid = perf_event_tid(event, current); 7270 7271 perf_event_header__init_id(&rec.header, &sample, event); 7272 ret = perf_output_begin(&handle, event, rec.header.size); 7273 7274 if (ret) 7275 return; 7276 7277 perf_output_put(&handle, rec); 7278 perf_event__output_id_sample(event, &handle, &sample); 7279 7280 perf_output_end(&handle); 7281 } 7282 7283 static int 7284 __perf_event_account_interrupt(struct perf_event *event, int throttle) 7285 { 7286 struct hw_perf_event *hwc = &event->hw; 7287 int ret = 0; 7288 u64 seq; 7289 7290 seq = __this_cpu_read(perf_throttled_seq); 7291 if (seq != hwc->interrupts_seq) { 7292 hwc->interrupts_seq = seq; 7293 hwc->interrupts = 1; 7294 } else { 7295 hwc->interrupts++; 7296 if (unlikely(throttle 7297 && hwc->interrupts >= max_samples_per_tick)) { 7298 __this_cpu_inc(perf_throttled_count); 7299 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); 7300 hwc->interrupts = MAX_INTERRUPTS; 7301 perf_log_throttle(event, 0); 7302 ret = 1; 7303 } 7304 } 7305 7306 if (event->attr.freq) { 7307 u64 now = perf_clock(); 7308 s64 delta = now - hwc->freq_time_stamp; 7309 7310 hwc->freq_time_stamp = now; 7311 7312 if (delta > 0 && delta < 2*TICK_NSEC) 7313 perf_adjust_period(event, delta, hwc->last_period, true); 7314 } 7315 7316 return ret; 7317 } 7318 7319 int perf_event_account_interrupt(struct perf_event *event) 7320 { 7321 return __perf_event_account_interrupt(event, 1); 7322 } 7323 7324 static bool sample_is_allowed(struct perf_event *event, struct pt_regs *regs) 7325 { 7326 /* 7327 * Due to interrupt latency (AKA "skid"), we may enter the 7328 * kernel before taking an overflow, even if the PMU is only 7329 * counting user events. 7330 * To avoid leaking information to userspace, we must always 7331 * reject kernel samples when exclude_kernel is set. 7332 */ 7333 if (event->attr.exclude_kernel && !user_mode(regs)) 7334 return false; 7335 7336 return true; 7337 } 7338 7339 /* 7340 * Generic event overflow handling, sampling. 7341 */ 7342 7343 static int __perf_event_overflow(struct perf_event *event, 7344 int throttle, struct perf_sample_data *data, 7345 struct pt_regs *regs) 7346 { 7347 int events = atomic_read(&event->event_limit); 7348 int ret = 0; 7349 7350 /* 7351 * Non-sampling counters might still use the PMI to fold short 7352 * hardware counters, ignore those. 7353 */ 7354 if (unlikely(!is_sampling_event(event))) 7355 return 0; 7356 7357 ret = __perf_event_account_interrupt(event, throttle); 7358 7359 /* 7360 * For security, drop the skid kernel samples if necessary. 7361 */ 7362 if (!sample_is_allowed(event, regs)) 7363 return ret; 7364 7365 /* 7366 * XXX event_limit might not quite work as expected on inherited 7367 * events 7368 */ 7369 7370 event->pending_kill = POLL_IN; 7371 if (events && atomic_dec_and_test(&event->event_limit)) { 7372 ret = 1; 7373 event->pending_kill = POLL_HUP; 7374 7375 perf_event_disable_inatomic(event); 7376 } 7377 7378 READ_ONCE(event->overflow_handler)(event, data, regs); 7379 7380 if (*perf_event_fasync(event) && event->pending_kill) { 7381 event->pending_wakeup = 1; 7382 irq_work_queue(&event->pending); 7383 } 7384 7385 return ret; 7386 } 7387 7388 int perf_event_overflow(struct perf_event *event, 7389 struct perf_sample_data *data, 7390 struct pt_regs *regs) 7391 { 7392 return __perf_event_overflow(event, 1, data, regs); 7393 } 7394 7395 /* 7396 * Generic software event infrastructure 7397 */ 7398 7399 struct swevent_htable { 7400 struct swevent_hlist *swevent_hlist; 7401 struct mutex hlist_mutex; 7402 int hlist_refcount; 7403 7404 /* Recursion avoidance in each contexts */ 7405 int recursion[PERF_NR_CONTEXTS]; 7406 }; 7407 7408 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable); 7409 7410 /* 7411 * We directly increment event->count and keep a second value in 7412 * event->hw.period_left to count intervals. This period event 7413 * is kept in the range [-sample_period, 0] so that we can use the 7414 * sign as trigger. 7415 */ 7416 7417 u64 perf_swevent_set_period(struct perf_event *event) 7418 { 7419 struct hw_perf_event *hwc = &event->hw; 7420 u64 period = hwc->last_period; 7421 u64 nr, offset; 7422 s64 old, val; 7423 7424 hwc->last_period = hwc->sample_period; 7425 7426 again: 7427 old = val = local64_read(&hwc->period_left); 7428 if (val < 0) 7429 return 0; 7430 7431 nr = div64_u64(period + val, period); 7432 offset = nr * period; 7433 val -= offset; 7434 if (local64_cmpxchg(&hwc->period_left, old, val) != old) 7435 goto again; 7436 7437 return nr; 7438 } 7439 7440 static void perf_swevent_overflow(struct perf_event *event, u64 overflow, 7441 struct perf_sample_data *data, 7442 struct pt_regs *regs) 7443 { 7444 struct hw_perf_event *hwc = &event->hw; 7445 int throttle = 0; 7446 7447 if (!overflow) 7448 overflow = perf_swevent_set_period(event); 7449 7450 if (hwc->interrupts == MAX_INTERRUPTS) 7451 return; 7452 7453 for (; overflow; overflow--) { 7454 if (__perf_event_overflow(event, throttle, 7455 data, regs)) { 7456 /* 7457 * We inhibit the overflow from happening when 7458 * hwc->interrupts == MAX_INTERRUPTS. 7459 */ 7460 break; 7461 } 7462 throttle = 1; 7463 } 7464 } 7465 7466 static void perf_swevent_event(struct perf_event *event, u64 nr, 7467 struct perf_sample_data *data, 7468 struct pt_regs *regs) 7469 { 7470 struct hw_perf_event *hwc = &event->hw; 7471 7472 local64_add(nr, &event->count); 7473 7474 if (!regs) 7475 return; 7476 7477 if (!is_sampling_event(event)) 7478 return; 7479 7480 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) { 7481 data->period = nr; 7482 return perf_swevent_overflow(event, 1, data, regs); 7483 } else 7484 data->period = event->hw.last_period; 7485 7486 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq) 7487 return perf_swevent_overflow(event, 1, data, regs); 7488 7489 if (local64_add_negative(nr, &hwc->period_left)) 7490 return; 7491 7492 perf_swevent_overflow(event, 0, data, regs); 7493 } 7494 7495 static int perf_exclude_event(struct perf_event *event, 7496 struct pt_regs *regs) 7497 { 7498 if (event->hw.state & PERF_HES_STOPPED) 7499 return 1; 7500 7501 if (regs) { 7502 if (event->attr.exclude_user && user_mode(regs)) 7503 return 1; 7504 7505 if (event->attr.exclude_kernel && !user_mode(regs)) 7506 return 1; 7507 } 7508 7509 return 0; 7510 } 7511 7512 static int perf_swevent_match(struct perf_event *event, 7513 enum perf_type_id type, 7514 u32 event_id, 7515 struct perf_sample_data *data, 7516 struct pt_regs *regs) 7517 { 7518 if (event->attr.type != type) 7519 return 0; 7520 7521 if (event->attr.config != event_id) 7522 return 0; 7523 7524 if (perf_exclude_event(event, regs)) 7525 return 0; 7526 7527 return 1; 7528 } 7529 7530 static inline u64 swevent_hash(u64 type, u32 event_id) 7531 { 7532 u64 val = event_id | (type << 32); 7533 7534 return hash_64(val, SWEVENT_HLIST_BITS); 7535 } 7536 7537 static inline struct hlist_head * 7538 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id) 7539 { 7540 u64 hash = swevent_hash(type, event_id); 7541 7542 return &hlist->heads[hash]; 7543 } 7544 7545 /* For the read side: events when they trigger */ 7546 static inline struct hlist_head * 7547 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id) 7548 { 7549 struct swevent_hlist *hlist; 7550 7551 hlist = rcu_dereference(swhash->swevent_hlist); 7552 if (!hlist) 7553 return NULL; 7554 7555 return __find_swevent_head(hlist, type, event_id); 7556 } 7557 7558 /* For the event head insertion and removal in the hlist */ 7559 static inline struct hlist_head * 7560 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event) 7561 { 7562 struct swevent_hlist *hlist; 7563 u32 event_id = event->attr.config; 7564 u64 type = event->attr.type; 7565 7566 /* 7567 * Event scheduling is always serialized against hlist allocation 7568 * and release. Which makes the protected version suitable here. 7569 * The context lock guarantees that. 7570 */ 7571 hlist = rcu_dereference_protected(swhash->swevent_hlist, 7572 lockdep_is_held(&event->ctx->lock)); 7573 if (!hlist) 7574 return NULL; 7575 7576 return __find_swevent_head(hlist, type, event_id); 7577 } 7578 7579 static void do_perf_sw_event(enum perf_type_id type, u32 event_id, 7580 u64 nr, 7581 struct perf_sample_data *data, 7582 struct pt_regs *regs) 7583 { 7584 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 7585 struct perf_event *event; 7586 struct hlist_head *head; 7587 7588 rcu_read_lock(); 7589 head = find_swevent_head_rcu(swhash, type, event_id); 7590 if (!head) 7591 goto end; 7592 7593 hlist_for_each_entry_rcu(event, head, hlist_entry) { 7594 if (perf_swevent_match(event, type, event_id, data, regs)) 7595 perf_swevent_event(event, nr, data, regs); 7596 } 7597 end: 7598 rcu_read_unlock(); 7599 } 7600 7601 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]); 7602 7603 int perf_swevent_get_recursion_context(void) 7604 { 7605 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 7606 7607 return get_recursion_context(swhash->recursion); 7608 } 7609 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context); 7610 7611 void perf_swevent_put_recursion_context(int rctx) 7612 { 7613 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 7614 7615 put_recursion_context(swhash->recursion, rctx); 7616 } 7617 7618 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) 7619 { 7620 struct perf_sample_data data; 7621 7622 if (WARN_ON_ONCE(!regs)) 7623 return; 7624 7625 perf_sample_data_init(&data, addr, 0); 7626 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs); 7627 } 7628 7629 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) 7630 { 7631 int rctx; 7632 7633 preempt_disable_notrace(); 7634 rctx = perf_swevent_get_recursion_context(); 7635 if (unlikely(rctx < 0)) 7636 goto fail; 7637 7638 ___perf_sw_event(event_id, nr, regs, addr); 7639 7640 perf_swevent_put_recursion_context(rctx); 7641 fail: 7642 preempt_enable_notrace(); 7643 } 7644 7645 static void perf_swevent_read(struct perf_event *event) 7646 { 7647 } 7648 7649 static int perf_swevent_add(struct perf_event *event, int flags) 7650 { 7651 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 7652 struct hw_perf_event *hwc = &event->hw; 7653 struct hlist_head *head; 7654 7655 if (is_sampling_event(event)) { 7656 hwc->last_period = hwc->sample_period; 7657 perf_swevent_set_period(event); 7658 } 7659 7660 hwc->state = !(flags & PERF_EF_START); 7661 7662 head = find_swevent_head(swhash, event); 7663 if (WARN_ON_ONCE(!head)) 7664 return -EINVAL; 7665 7666 hlist_add_head_rcu(&event->hlist_entry, head); 7667 perf_event_update_userpage(event); 7668 7669 return 0; 7670 } 7671 7672 static void perf_swevent_del(struct perf_event *event, int flags) 7673 { 7674 hlist_del_rcu(&event->hlist_entry); 7675 } 7676 7677 static void perf_swevent_start(struct perf_event *event, int flags) 7678 { 7679 event->hw.state = 0; 7680 } 7681 7682 static void perf_swevent_stop(struct perf_event *event, int flags) 7683 { 7684 event->hw.state = PERF_HES_STOPPED; 7685 } 7686 7687 /* Deref the hlist from the update side */ 7688 static inline struct swevent_hlist * 7689 swevent_hlist_deref(struct swevent_htable *swhash) 7690 { 7691 return rcu_dereference_protected(swhash->swevent_hlist, 7692 lockdep_is_held(&swhash->hlist_mutex)); 7693 } 7694 7695 static void swevent_hlist_release(struct swevent_htable *swhash) 7696 { 7697 struct swevent_hlist *hlist = swevent_hlist_deref(swhash); 7698 7699 if (!hlist) 7700 return; 7701 7702 RCU_INIT_POINTER(swhash->swevent_hlist, NULL); 7703 kfree_rcu(hlist, rcu_head); 7704 } 7705 7706 static void swevent_hlist_put_cpu(int cpu) 7707 { 7708 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 7709 7710 mutex_lock(&swhash->hlist_mutex); 7711 7712 if (!--swhash->hlist_refcount) 7713 swevent_hlist_release(swhash); 7714 7715 mutex_unlock(&swhash->hlist_mutex); 7716 } 7717 7718 static void swevent_hlist_put(void) 7719 { 7720 int cpu; 7721 7722 for_each_possible_cpu(cpu) 7723 swevent_hlist_put_cpu(cpu); 7724 } 7725 7726 static int swevent_hlist_get_cpu(int cpu) 7727 { 7728 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 7729 int err = 0; 7730 7731 mutex_lock(&swhash->hlist_mutex); 7732 if (!swevent_hlist_deref(swhash) && 7733 cpumask_test_cpu(cpu, perf_online_mask)) { 7734 struct swevent_hlist *hlist; 7735 7736 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL); 7737 if (!hlist) { 7738 err = -ENOMEM; 7739 goto exit; 7740 } 7741 rcu_assign_pointer(swhash->swevent_hlist, hlist); 7742 } 7743 swhash->hlist_refcount++; 7744 exit: 7745 mutex_unlock(&swhash->hlist_mutex); 7746 7747 return err; 7748 } 7749 7750 static int swevent_hlist_get(void) 7751 { 7752 int err, cpu, failed_cpu; 7753 7754 mutex_lock(&pmus_lock); 7755 for_each_possible_cpu(cpu) { 7756 err = swevent_hlist_get_cpu(cpu); 7757 if (err) { 7758 failed_cpu = cpu; 7759 goto fail; 7760 } 7761 } 7762 mutex_unlock(&pmus_lock); 7763 return 0; 7764 fail: 7765 for_each_possible_cpu(cpu) { 7766 if (cpu == failed_cpu) 7767 break; 7768 swevent_hlist_put_cpu(cpu); 7769 } 7770 mutex_unlock(&pmus_lock); 7771 return err; 7772 } 7773 7774 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX]; 7775 7776 static void sw_perf_event_destroy(struct perf_event *event) 7777 { 7778 u64 event_id = event->attr.config; 7779 7780 WARN_ON(event->parent); 7781 7782 static_key_slow_dec(&perf_swevent_enabled[event_id]); 7783 swevent_hlist_put(); 7784 } 7785 7786 static int perf_swevent_init(struct perf_event *event) 7787 { 7788 u64 event_id = event->attr.config; 7789 7790 if (event->attr.type != PERF_TYPE_SOFTWARE) 7791 return -ENOENT; 7792 7793 /* 7794 * no branch sampling for software events 7795 */ 7796 if (has_branch_stack(event)) 7797 return -EOPNOTSUPP; 7798 7799 switch (event_id) { 7800 case PERF_COUNT_SW_CPU_CLOCK: 7801 case PERF_COUNT_SW_TASK_CLOCK: 7802 return -ENOENT; 7803 7804 default: 7805 break; 7806 } 7807 7808 if (event_id >= PERF_COUNT_SW_MAX) 7809 return -ENOENT; 7810 7811 if (!event->parent) { 7812 int err; 7813 7814 err = swevent_hlist_get(); 7815 if (err) 7816 return err; 7817 7818 static_key_slow_inc(&perf_swevent_enabled[event_id]); 7819 event->destroy = sw_perf_event_destroy; 7820 } 7821 7822 return 0; 7823 } 7824 7825 static struct pmu perf_swevent = { 7826 .task_ctx_nr = perf_sw_context, 7827 7828 .capabilities = PERF_PMU_CAP_NO_NMI, 7829 7830 .event_init = perf_swevent_init, 7831 .add = perf_swevent_add, 7832 .del = perf_swevent_del, 7833 .start = perf_swevent_start, 7834 .stop = perf_swevent_stop, 7835 .read = perf_swevent_read, 7836 }; 7837 7838 #ifdef CONFIG_EVENT_TRACING 7839 7840 static int perf_tp_filter_match(struct perf_event *event, 7841 struct perf_sample_data *data) 7842 { 7843 void *record = data->raw->frag.data; 7844 7845 /* only top level events have filters set */ 7846 if (event->parent) 7847 event = event->parent; 7848 7849 if (likely(!event->filter) || filter_match_preds(event->filter, record)) 7850 return 1; 7851 return 0; 7852 } 7853 7854 static int perf_tp_event_match(struct perf_event *event, 7855 struct perf_sample_data *data, 7856 struct pt_regs *regs) 7857 { 7858 if (event->hw.state & PERF_HES_STOPPED) 7859 return 0; 7860 /* 7861 * All tracepoints are from kernel-space. 7862 */ 7863 if (event->attr.exclude_kernel) 7864 return 0; 7865 7866 if (!perf_tp_filter_match(event, data)) 7867 return 0; 7868 7869 return 1; 7870 } 7871 7872 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx, 7873 struct trace_event_call *call, u64 count, 7874 struct pt_regs *regs, struct hlist_head *head, 7875 struct task_struct *task) 7876 { 7877 struct bpf_prog *prog = call->prog; 7878 7879 if (prog) { 7880 *(struct pt_regs **)raw_data = regs; 7881 if (!trace_call_bpf(prog, raw_data) || hlist_empty(head)) { 7882 perf_swevent_put_recursion_context(rctx); 7883 return; 7884 } 7885 } 7886 perf_tp_event(call->event.type, count, raw_data, size, regs, head, 7887 rctx, task); 7888 } 7889 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit); 7890 7891 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size, 7892 struct pt_regs *regs, struct hlist_head *head, int rctx, 7893 struct task_struct *task) 7894 { 7895 struct perf_sample_data data; 7896 struct perf_event *event; 7897 7898 struct perf_raw_record raw = { 7899 .frag = { 7900 .size = entry_size, 7901 .data = record, 7902 }, 7903 }; 7904 7905 perf_sample_data_init(&data, 0, 0); 7906 data.raw = &raw; 7907 7908 perf_trace_buf_update(record, event_type); 7909 7910 hlist_for_each_entry_rcu(event, head, hlist_entry) { 7911 if (perf_tp_event_match(event, &data, regs)) 7912 perf_swevent_event(event, count, &data, regs); 7913 } 7914 7915 /* 7916 * If we got specified a target task, also iterate its context and 7917 * deliver this event there too. 7918 */ 7919 if (task && task != current) { 7920 struct perf_event_context *ctx; 7921 struct trace_entry *entry = record; 7922 7923 rcu_read_lock(); 7924 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]); 7925 if (!ctx) 7926 goto unlock; 7927 7928 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 7929 if (event->attr.type != PERF_TYPE_TRACEPOINT) 7930 continue; 7931 if (event->attr.config != entry->type) 7932 continue; 7933 if (perf_tp_event_match(event, &data, regs)) 7934 perf_swevent_event(event, count, &data, regs); 7935 } 7936 unlock: 7937 rcu_read_unlock(); 7938 } 7939 7940 perf_swevent_put_recursion_context(rctx); 7941 } 7942 EXPORT_SYMBOL_GPL(perf_tp_event); 7943 7944 static void tp_perf_event_destroy(struct perf_event *event) 7945 { 7946 perf_trace_destroy(event); 7947 } 7948 7949 static int perf_tp_event_init(struct perf_event *event) 7950 { 7951 int err; 7952 7953 if (event->attr.type != PERF_TYPE_TRACEPOINT) 7954 return -ENOENT; 7955 7956 /* 7957 * no branch sampling for tracepoint events 7958 */ 7959 if (has_branch_stack(event)) 7960 return -EOPNOTSUPP; 7961 7962 err = perf_trace_init(event); 7963 if (err) 7964 return err; 7965 7966 event->destroy = tp_perf_event_destroy; 7967 7968 return 0; 7969 } 7970 7971 static struct pmu perf_tracepoint = { 7972 .task_ctx_nr = perf_sw_context, 7973 7974 .event_init = perf_tp_event_init, 7975 .add = perf_trace_add, 7976 .del = perf_trace_del, 7977 .start = perf_swevent_start, 7978 .stop = perf_swevent_stop, 7979 .read = perf_swevent_read, 7980 }; 7981 7982 static inline void perf_tp_register(void) 7983 { 7984 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT); 7985 } 7986 7987 static void perf_event_free_filter(struct perf_event *event) 7988 { 7989 ftrace_profile_free_filter(event); 7990 } 7991 7992 #ifdef CONFIG_BPF_SYSCALL 7993 static void bpf_overflow_handler(struct perf_event *event, 7994 struct perf_sample_data *data, 7995 struct pt_regs *regs) 7996 { 7997 struct bpf_perf_event_data_kern ctx = { 7998 .data = data, 7999 .regs = regs, 8000 }; 8001 int ret = 0; 8002 8003 preempt_disable(); 8004 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) 8005 goto out; 8006 rcu_read_lock(); 8007 ret = BPF_PROG_RUN(event->prog, &ctx); 8008 rcu_read_unlock(); 8009 out: 8010 __this_cpu_dec(bpf_prog_active); 8011 preempt_enable(); 8012 if (!ret) 8013 return; 8014 8015 event->orig_overflow_handler(event, data, regs); 8016 } 8017 8018 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd) 8019 { 8020 struct bpf_prog *prog; 8021 8022 if (event->overflow_handler_context) 8023 /* hw breakpoint or kernel counter */ 8024 return -EINVAL; 8025 8026 if (event->prog) 8027 return -EEXIST; 8028 8029 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT); 8030 if (IS_ERR(prog)) 8031 return PTR_ERR(prog); 8032 8033 event->prog = prog; 8034 event->orig_overflow_handler = READ_ONCE(event->overflow_handler); 8035 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler); 8036 return 0; 8037 } 8038 8039 static void perf_event_free_bpf_handler(struct perf_event *event) 8040 { 8041 struct bpf_prog *prog = event->prog; 8042 8043 if (!prog) 8044 return; 8045 8046 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler); 8047 event->prog = NULL; 8048 bpf_prog_put(prog); 8049 } 8050 #else 8051 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd) 8052 { 8053 return -EOPNOTSUPP; 8054 } 8055 static void perf_event_free_bpf_handler(struct perf_event *event) 8056 { 8057 } 8058 #endif 8059 8060 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) 8061 { 8062 bool is_kprobe, is_tracepoint; 8063 struct bpf_prog *prog; 8064 8065 if (event->attr.type != PERF_TYPE_TRACEPOINT) 8066 return perf_event_set_bpf_handler(event, prog_fd); 8067 8068 if (event->tp_event->prog) 8069 return -EEXIST; 8070 8071 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE; 8072 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT; 8073 if (!is_kprobe && !is_tracepoint) 8074 /* bpf programs can only be attached to u/kprobe or tracepoint */ 8075 return -EINVAL; 8076 8077 prog = bpf_prog_get(prog_fd); 8078 if (IS_ERR(prog)) 8079 return PTR_ERR(prog); 8080 8081 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) || 8082 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT)) { 8083 /* valid fd, but invalid bpf program type */ 8084 bpf_prog_put(prog); 8085 return -EINVAL; 8086 } 8087 8088 if (is_tracepoint) { 8089 int off = trace_event_get_offsets(event->tp_event); 8090 8091 if (prog->aux->max_ctx_offset > off) { 8092 bpf_prog_put(prog); 8093 return -EACCES; 8094 } 8095 } 8096 event->tp_event->prog = prog; 8097 8098 return 0; 8099 } 8100 8101 static void perf_event_free_bpf_prog(struct perf_event *event) 8102 { 8103 struct bpf_prog *prog; 8104 8105 perf_event_free_bpf_handler(event); 8106 8107 if (!event->tp_event) 8108 return; 8109 8110 prog = event->tp_event->prog; 8111 if (prog) { 8112 event->tp_event->prog = NULL; 8113 bpf_prog_put(prog); 8114 } 8115 } 8116 8117 #else 8118 8119 static inline void perf_tp_register(void) 8120 { 8121 } 8122 8123 static void perf_event_free_filter(struct perf_event *event) 8124 { 8125 } 8126 8127 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) 8128 { 8129 return -ENOENT; 8130 } 8131 8132 static void perf_event_free_bpf_prog(struct perf_event *event) 8133 { 8134 } 8135 #endif /* CONFIG_EVENT_TRACING */ 8136 8137 #ifdef CONFIG_HAVE_HW_BREAKPOINT 8138 void perf_bp_event(struct perf_event *bp, void *data) 8139 { 8140 struct perf_sample_data sample; 8141 struct pt_regs *regs = data; 8142 8143 perf_sample_data_init(&sample, bp->attr.bp_addr, 0); 8144 8145 if (!bp->hw.state && !perf_exclude_event(bp, regs)) 8146 perf_swevent_event(bp, 1, &sample, regs); 8147 } 8148 #endif 8149 8150 /* 8151 * Allocate a new address filter 8152 */ 8153 static struct perf_addr_filter * 8154 perf_addr_filter_new(struct perf_event *event, struct list_head *filters) 8155 { 8156 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu); 8157 struct perf_addr_filter *filter; 8158 8159 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node); 8160 if (!filter) 8161 return NULL; 8162 8163 INIT_LIST_HEAD(&filter->entry); 8164 list_add_tail(&filter->entry, filters); 8165 8166 return filter; 8167 } 8168 8169 static void free_filters_list(struct list_head *filters) 8170 { 8171 struct perf_addr_filter *filter, *iter; 8172 8173 list_for_each_entry_safe(filter, iter, filters, entry) { 8174 if (filter->inode) 8175 iput(filter->inode); 8176 list_del(&filter->entry); 8177 kfree(filter); 8178 } 8179 } 8180 8181 /* 8182 * Free existing address filters and optionally install new ones 8183 */ 8184 static void perf_addr_filters_splice(struct perf_event *event, 8185 struct list_head *head) 8186 { 8187 unsigned long flags; 8188 LIST_HEAD(list); 8189 8190 if (!has_addr_filter(event)) 8191 return; 8192 8193 /* don't bother with children, they don't have their own filters */ 8194 if (event->parent) 8195 return; 8196 8197 raw_spin_lock_irqsave(&event->addr_filters.lock, flags); 8198 8199 list_splice_init(&event->addr_filters.list, &list); 8200 if (head) 8201 list_splice(head, &event->addr_filters.list); 8202 8203 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags); 8204 8205 free_filters_list(&list); 8206 } 8207 8208 /* 8209 * Scan through mm's vmas and see if one of them matches the 8210 * @filter; if so, adjust filter's address range. 8211 * Called with mm::mmap_sem down for reading. 8212 */ 8213 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter, 8214 struct mm_struct *mm) 8215 { 8216 struct vm_area_struct *vma; 8217 8218 for (vma = mm->mmap; vma; vma = vma->vm_next) { 8219 struct file *file = vma->vm_file; 8220 unsigned long off = vma->vm_pgoff << PAGE_SHIFT; 8221 unsigned long vma_size = vma->vm_end - vma->vm_start; 8222 8223 if (!file) 8224 continue; 8225 8226 if (!perf_addr_filter_match(filter, file, off, vma_size)) 8227 continue; 8228 8229 return vma->vm_start; 8230 } 8231 8232 return 0; 8233 } 8234 8235 /* 8236 * Update event's address range filters based on the 8237 * task's existing mappings, if any. 8238 */ 8239 static void perf_event_addr_filters_apply(struct perf_event *event) 8240 { 8241 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 8242 struct task_struct *task = READ_ONCE(event->ctx->task); 8243 struct perf_addr_filter *filter; 8244 struct mm_struct *mm = NULL; 8245 unsigned int count = 0; 8246 unsigned long flags; 8247 8248 /* 8249 * We may observe TASK_TOMBSTONE, which means that the event tear-down 8250 * will stop on the parent's child_mutex that our caller is also holding 8251 */ 8252 if (task == TASK_TOMBSTONE) 8253 return; 8254 8255 if (!ifh->nr_file_filters) 8256 return; 8257 8258 mm = get_task_mm(event->ctx->task); 8259 if (!mm) 8260 goto restart; 8261 8262 down_read(&mm->mmap_sem); 8263 8264 raw_spin_lock_irqsave(&ifh->lock, flags); 8265 list_for_each_entry(filter, &ifh->list, entry) { 8266 event->addr_filters_offs[count] = 0; 8267 8268 /* 8269 * Adjust base offset if the filter is associated to a binary 8270 * that needs to be mapped: 8271 */ 8272 if (filter->inode) 8273 event->addr_filters_offs[count] = 8274 perf_addr_filter_apply(filter, mm); 8275 8276 count++; 8277 } 8278 8279 event->addr_filters_gen++; 8280 raw_spin_unlock_irqrestore(&ifh->lock, flags); 8281 8282 up_read(&mm->mmap_sem); 8283 8284 mmput(mm); 8285 8286 restart: 8287 perf_event_stop(event, 1); 8288 } 8289 8290 /* 8291 * Address range filtering: limiting the data to certain 8292 * instruction address ranges. Filters are ioctl()ed to us from 8293 * userspace as ascii strings. 8294 * 8295 * Filter string format: 8296 * 8297 * ACTION RANGE_SPEC 8298 * where ACTION is one of the 8299 * * "filter": limit the trace to this region 8300 * * "start": start tracing from this address 8301 * * "stop": stop tracing at this address/region; 8302 * RANGE_SPEC is 8303 * * for kernel addresses: <start address>[/<size>] 8304 * * for object files: <start address>[/<size>]@</path/to/object/file> 8305 * 8306 * if <size> is not specified, the range is treated as a single address. 8307 */ 8308 enum { 8309 IF_ACT_NONE = -1, 8310 IF_ACT_FILTER, 8311 IF_ACT_START, 8312 IF_ACT_STOP, 8313 IF_SRC_FILE, 8314 IF_SRC_KERNEL, 8315 IF_SRC_FILEADDR, 8316 IF_SRC_KERNELADDR, 8317 }; 8318 8319 enum { 8320 IF_STATE_ACTION = 0, 8321 IF_STATE_SOURCE, 8322 IF_STATE_END, 8323 }; 8324 8325 static const match_table_t if_tokens = { 8326 { IF_ACT_FILTER, "filter" }, 8327 { IF_ACT_START, "start" }, 8328 { IF_ACT_STOP, "stop" }, 8329 { IF_SRC_FILE, "%u/%u@%s" }, 8330 { IF_SRC_KERNEL, "%u/%u" }, 8331 { IF_SRC_FILEADDR, "%u@%s" }, 8332 { IF_SRC_KERNELADDR, "%u" }, 8333 { IF_ACT_NONE, NULL }, 8334 }; 8335 8336 /* 8337 * Address filter string parser 8338 */ 8339 static int 8340 perf_event_parse_addr_filter(struct perf_event *event, char *fstr, 8341 struct list_head *filters) 8342 { 8343 struct perf_addr_filter *filter = NULL; 8344 char *start, *orig, *filename = NULL; 8345 struct path path; 8346 substring_t args[MAX_OPT_ARGS]; 8347 int state = IF_STATE_ACTION, token; 8348 unsigned int kernel = 0; 8349 int ret = -EINVAL; 8350 8351 orig = fstr = kstrdup(fstr, GFP_KERNEL); 8352 if (!fstr) 8353 return -ENOMEM; 8354 8355 while ((start = strsep(&fstr, " ,\n")) != NULL) { 8356 ret = -EINVAL; 8357 8358 if (!*start) 8359 continue; 8360 8361 /* filter definition begins */ 8362 if (state == IF_STATE_ACTION) { 8363 filter = perf_addr_filter_new(event, filters); 8364 if (!filter) 8365 goto fail; 8366 } 8367 8368 token = match_token(start, if_tokens, args); 8369 switch (token) { 8370 case IF_ACT_FILTER: 8371 case IF_ACT_START: 8372 filter->filter = 1; 8373 8374 case IF_ACT_STOP: 8375 if (state != IF_STATE_ACTION) 8376 goto fail; 8377 8378 state = IF_STATE_SOURCE; 8379 break; 8380 8381 case IF_SRC_KERNELADDR: 8382 case IF_SRC_KERNEL: 8383 kernel = 1; 8384 8385 case IF_SRC_FILEADDR: 8386 case IF_SRC_FILE: 8387 if (state != IF_STATE_SOURCE) 8388 goto fail; 8389 8390 if (token == IF_SRC_FILE || token == IF_SRC_KERNEL) 8391 filter->range = 1; 8392 8393 *args[0].to = 0; 8394 ret = kstrtoul(args[0].from, 0, &filter->offset); 8395 if (ret) 8396 goto fail; 8397 8398 if (filter->range) { 8399 *args[1].to = 0; 8400 ret = kstrtoul(args[1].from, 0, &filter->size); 8401 if (ret) 8402 goto fail; 8403 } 8404 8405 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) { 8406 int fpos = filter->range ? 2 : 1; 8407 8408 filename = match_strdup(&args[fpos]); 8409 if (!filename) { 8410 ret = -ENOMEM; 8411 goto fail; 8412 } 8413 } 8414 8415 state = IF_STATE_END; 8416 break; 8417 8418 default: 8419 goto fail; 8420 } 8421 8422 /* 8423 * Filter definition is fully parsed, validate and install it. 8424 * Make sure that it doesn't contradict itself or the event's 8425 * attribute. 8426 */ 8427 if (state == IF_STATE_END) { 8428 ret = -EINVAL; 8429 if (kernel && event->attr.exclude_kernel) 8430 goto fail; 8431 8432 if (!kernel) { 8433 if (!filename) 8434 goto fail; 8435 8436 /* 8437 * For now, we only support file-based filters 8438 * in per-task events; doing so for CPU-wide 8439 * events requires additional context switching 8440 * trickery, since same object code will be 8441 * mapped at different virtual addresses in 8442 * different processes. 8443 */ 8444 ret = -EOPNOTSUPP; 8445 if (!event->ctx->task) 8446 goto fail_free_name; 8447 8448 /* look up the path and grab its inode */ 8449 ret = kern_path(filename, LOOKUP_FOLLOW, &path); 8450 if (ret) 8451 goto fail_free_name; 8452 8453 filter->inode = igrab(d_inode(path.dentry)); 8454 path_put(&path); 8455 kfree(filename); 8456 filename = NULL; 8457 8458 ret = -EINVAL; 8459 if (!filter->inode || 8460 !S_ISREG(filter->inode->i_mode)) 8461 /* free_filters_list() will iput() */ 8462 goto fail; 8463 8464 event->addr_filters.nr_file_filters++; 8465 } 8466 8467 /* ready to consume more filters */ 8468 state = IF_STATE_ACTION; 8469 filter = NULL; 8470 } 8471 } 8472 8473 if (state != IF_STATE_ACTION) 8474 goto fail; 8475 8476 kfree(orig); 8477 8478 return 0; 8479 8480 fail_free_name: 8481 kfree(filename); 8482 fail: 8483 free_filters_list(filters); 8484 kfree(orig); 8485 8486 return ret; 8487 } 8488 8489 static int 8490 perf_event_set_addr_filter(struct perf_event *event, char *filter_str) 8491 { 8492 LIST_HEAD(filters); 8493 int ret; 8494 8495 /* 8496 * Since this is called in perf_ioctl() path, we're already holding 8497 * ctx::mutex. 8498 */ 8499 lockdep_assert_held(&event->ctx->mutex); 8500 8501 if (WARN_ON_ONCE(event->parent)) 8502 return -EINVAL; 8503 8504 ret = perf_event_parse_addr_filter(event, filter_str, &filters); 8505 if (ret) 8506 goto fail_clear_files; 8507 8508 ret = event->pmu->addr_filters_validate(&filters); 8509 if (ret) 8510 goto fail_free_filters; 8511 8512 /* remove existing filters, if any */ 8513 perf_addr_filters_splice(event, &filters); 8514 8515 /* install new filters */ 8516 perf_event_for_each_child(event, perf_event_addr_filters_apply); 8517 8518 return ret; 8519 8520 fail_free_filters: 8521 free_filters_list(&filters); 8522 8523 fail_clear_files: 8524 event->addr_filters.nr_file_filters = 0; 8525 8526 return ret; 8527 } 8528 8529 static int perf_event_set_filter(struct perf_event *event, void __user *arg) 8530 { 8531 char *filter_str; 8532 int ret = -EINVAL; 8533 8534 if ((event->attr.type != PERF_TYPE_TRACEPOINT || 8535 !IS_ENABLED(CONFIG_EVENT_TRACING)) && 8536 !has_addr_filter(event)) 8537 return -EINVAL; 8538 8539 filter_str = strndup_user(arg, PAGE_SIZE); 8540 if (IS_ERR(filter_str)) 8541 return PTR_ERR(filter_str); 8542 8543 if (IS_ENABLED(CONFIG_EVENT_TRACING) && 8544 event->attr.type == PERF_TYPE_TRACEPOINT) 8545 ret = ftrace_profile_set_filter(event, event->attr.config, 8546 filter_str); 8547 else if (has_addr_filter(event)) 8548 ret = perf_event_set_addr_filter(event, filter_str); 8549 8550 kfree(filter_str); 8551 return ret; 8552 } 8553 8554 /* 8555 * hrtimer based swevent callback 8556 */ 8557 8558 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer) 8559 { 8560 enum hrtimer_restart ret = HRTIMER_RESTART; 8561 struct perf_sample_data data; 8562 struct pt_regs *regs; 8563 struct perf_event *event; 8564 u64 period; 8565 8566 event = container_of(hrtimer, struct perf_event, hw.hrtimer); 8567 8568 if (event->state != PERF_EVENT_STATE_ACTIVE) 8569 return HRTIMER_NORESTART; 8570 8571 event->pmu->read(event); 8572 8573 perf_sample_data_init(&data, 0, event->hw.last_period); 8574 regs = get_irq_regs(); 8575 8576 if (regs && !perf_exclude_event(event, regs)) { 8577 if (!(event->attr.exclude_idle && is_idle_task(current))) 8578 if (__perf_event_overflow(event, 1, &data, regs)) 8579 ret = HRTIMER_NORESTART; 8580 } 8581 8582 period = max_t(u64, 10000, event->hw.sample_period); 8583 hrtimer_forward_now(hrtimer, ns_to_ktime(period)); 8584 8585 return ret; 8586 } 8587 8588 static void perf_swevent_start_hrtimer(struct perf_event *event) 8589 { 8590 struct hw_perf_event *hwc = &event->hw; 8591 s64 period; 8592 8593 if (!is_sampling_event(event)) 8594 return; 8595 8596 period = local64_read(&hwc->period_left); 8597 if (period) { 8598 if (period < 0) 8599 period = 10000; 8600 8601 local64_set(&hwc->period_left, 0); 8602 } else { 8603 period = max_t(u64, 10000, hwc->sample_period); 8604 } 8605 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period), 8606 HRTIMER_MODE_REL_PINNED); 8607 } 8608 8609 static void perf_swevent_cancel_hrtimer(struct perf_event *event) 8610 { 8611 struct hw_perf_event *hwc = &event->hw; 8612 8613 if (is_sampling_event(event)) { 8614 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer); 8615 local64_set(&hwc->period_left, ktime_to_ns(remaining)); 8616 8617 hrtimer_cancel(&hwc->hrtimer); 8618 } 8619 } 8620 8621 static void perf_swevent_init_hrtimer(struct perf_event *event) 8622 { 8623 struct hw_perf_event *hwc = &event->hw; 8624 8625 if (!is_sampling_event(event)) 8626 return; 8627 8628 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 8629 hwc->hrtimer.function = perf_swevent_hrtimer; 8630 8631 /* 8632 * Since hrtimers have a fixed rate, we can do a static freq->period 8633 * mapping and avoid the whole period adjust feedback stuff. 8634 */ 8635 if (event->attr.freq) { 8636 long freq = event->attr.sample_freq; 8637 8638 event->attr.sample_period = NSEC_PER_SEC / freq; 8639 hwc->sample_period = event->attr.sample_period; 8640 local64_set(&hwc->period_left, hwc->sample_period); 8641 hwc->last_period = hwc->sample_period; 8642 event->attr.freq = 0; 8643 } 8644 } 8645 8646 /* 8647 * Software event: cpu wall time clock 8648 */ 8649 8650 static void cpu_clock_event_update(struct perf_event *event) 8651 { 8652 s64 prev; 8653 u64 now; 8654 8655 now = local_clock(); 8656 prev = local64_xchg(&event->hw.prev_count, now); 8657 local64_add(now - prev, &event->count); 8658 } 8659 8660 static void cpu_clock_event_start(struct perf_event *event, int flags) 8661 { 8662 local64_set(&event->hw.prev_count, local_clock()); 8663 perf_swevent_start_hrtimer(event); 8664 } 8665 8666 static void cpu_clock_event_stop(struct perf_event *event, int flags) 8667 { 8668 perf_swevent_cancel_hrtimer(event); 8669 cpu_clock_event_update(event); 8670 } 8671 8672 static int cpu_clock_event_add(struct perf_event *event, int flags) 8673 { 8674 if (flags & PERF_EF_START) 8675 cpu_clock_event_start(event, flags); 8676 perf_event_update_userpage(event); 8677 8678 return 0; 8679 } 8680 8681 static void cpu_clock_event_del(struct perf_event *event, int flags) 8682 { 8683 cpu_clock_event_stop(event, flags); 8684 } 8685 8686 static void cpu_clock_event_read(struct perf_event *event) 8687 { 8688 cpu_clock_event_update(event); 8689 } 8690 8691 static int cpu_clock_event_init(struct perf_event *event) 8692 { 8693 if (event->attr.type != PERF_TYPE_SOFTWARE) 8694 return -ENOENT; 8695 8696 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK) 8697 return -ENOENT; 8698 8699 /* 8700 * no branch sampling for software events 8701 */ 8702 if (has_branch_stack(event)) 8703 return -EOPNOTSUPP; 8704 8705 perf_swevent_init_hrtimer(event); 8706 8707 return 0; 8708 } 8709 8710 static struct pmu perf_cpu_clock = { 8711 .task_ctx_nr = perf_sw_context, 8712 8713 .capabilities = PERF_PMU_CAP_NO_NMI, 8714 8715 .event_init = cpu_clock_event_init, 8716 .add = cpu_clock_event_add, 8717 .del = cpu_clock_event_del, 8718 .start = cpu_clock_event_start, 8719 .stop = cpu_clock_event_stop, 8720 .read = cpu_clock_event_read, 8721 }; 8722 8723 /* 8724 * Software event: task time clock 8725 */ 8726 8727 static void task_clock_event_update(struct perf_event *event, u64 now) 8728 { 8729 u64 prev; 8730 s64 delta; 8731 8732 prev = local64_xchg(&event->hw.prev_count, now); 8733 delta = now - prev; 8734 local64_add(delta, &event->count); 8735 } 8736 8737 static void task_clock_event_start(struct perf_event *event, int flags) 8738 { 8739 local64_set(&event->hw.prev_count, event->ctx->time); 8740 perf_swevent_start_hrtimer(event); 8741 } 8742 8743 static void task_clock_event_stop(struct perf_event *event, int flags) 8744 { 8745 perf_swevent_cancel_hrtimer(event); 8746 task_clock_event_update(event, event->ctx->time); 8747 } 8748 8749 static int task_clock_event_add(struct perf_event *event, int flags) 8750 { 8751 if (flags & PERF_EF_START) 8752 task_clock_event_start(event, flags); 8753 perf_event_update_userpage(event); 8754 8755 return 0; 8756 } 8757 8758 static void task_clock_event_del(struct perf_event *event, int flags) 8759 { 8760 task_clock_event_stop(event, PERF_EF_UPDATE); 8761 } 8762 8763 static void task_clock_event_read(struct perf_event *event) 8764 { 8765 u64 now = perf_clock(); 8766 u64 delta = now - event->ctx->timestamp; 8767 u64 time = event->ctx->time + delta; 8768 8769 task_clock_event_update(event, time); 8770 } 8771 8772 static int task_clock_event_init(struct perf_event *event) 8773 { 8774 if (event->attr.type != PERF_TYPE_SOFTWARE) 8775 return -ENOENT; 8776 8777 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK) 8778 return -ENOENT; 8779 8780 /* 8781 * no branch sampling for software events 8782 */ 8783 if (has_branch_stack(event)) 8784 return -EOPNOTSUPP; 8785 8786 perf_swevent_init_hrtimer(event); 8787 8788 return 0; 8789 } 8790 8791 static struct pmu perf_task_clock = { 8792 .task_ctx_nr = perf_sw_context, 8793 8794 .capabilities = PERF_PMU_CAP_NO_NMI, 8795 8796 .event_init = task_clock_event_init, 8797 .add = task_clock_event_add, 8798 .del = task_clock_event_del, 8799 .start = task_clock_event_start, 8800 .stop = task_clock_event_stop, 8801 .read = task_clock_event_read, 8802 }; 8803 8804 static void perf_pmu_nop_void(struct pmu *pmu) 8805 { 8806 } 8807 8808 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags) 8809 { 8810 } 8811 8812 static int perf_pmu_nop_int(struct pmu *pmu) 8813 { 8814 return 0; 8815 } 8816 8817 static DEFINE_PER_CPU(unsigned int, nop_txn_flags); 8818 8819 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags) 8820 { 8821 __this_cpu_write(nop_txn_flags, flags); 8822 8823 if (flags & ~PERF_PMU_TXN_ADD) 8824 return; 8825 8826 perf_pmu_disable(pmu); 8827 } 8828 8829 static int perf_pmu_commit_txn(struct pmu *pmu) 8830 { 8831 unsigned int flags = __this_cpu_read(nop_txn_flags); 8832 8833 __this_cpu_write(nop_txn_flags, 0); 8834 8835 if (flags & ~PERF_PMU_TXN_ADD) 8836 return 0; 8837 8838 perf_pmu_enable(pmu); 8839 return 0; 8840 } 8841 8842 static void perf_pmu_cancel_txn(struct pmu *pmu) 8843 { 8844 unsigned int flags = __this_cpu_read(nop_txn_flags); 8845 8846 __this_cpu_write(nop_txn_flags, 0); 8847 8848 if (flags & ~PERF_PMU_TXN_ADD) 8849 return; 8850 8851 perf_pmu_enable(pmu); 8852 } 8853 8854 static int perf_event_idx_default(struct perf_event *event) 8855 { 8856 return 0; 8857 } 8858 8859 /* 8860 * Ensures all contexts with the same task_ctx_nr have the same 8861 * pmu_cpu_context too. 8862 */ 8863 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn) 8864 { 8865 struct pmu *pmu; 8866 8867 if (ctxn < 0) 8868 return NULL; 8869 8870 list_for_each_entry(pmu, &pmus, entry) { 8871 if (pmu->task_ctx_nr == ctxn) 8872 return pmu->pmu_cpu_context; 8873 } 8874 8875 return NULL; 8876 } 8877 8878 static void free_pmu_context(struct pmu *pmu) 8879 { 8880 mutex_lock(&pmus_lock); 8881 free_percpu(pmu->pmu_cpu_context); 8882 mutex_unlock(&pmus_lock); 8883 } 8884 8885 /* 8886 * Let userspace know that this PMU supports address range filtering: 8887 */ 8888 static ssize_t nr_addr_filters_show(struct device *dev, 8889 struct device_attribute *attr, 8890 char *page) 8891 { 8892 struct pmu *pmu = dev_get_drvdata(dev); 8893 8894 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters); 8895 } 8896 DEVICE_ATTR_RO(nr_addr_filters); 8897 8898 static struct idr pmu_idr; 8899 8900 static ssize_t 8901 type_show(struct device *dev, struct device_attribute *attr, char *page) 8902 { 8903 struct pmu *pmu = dev_get_drvdata(dev); 8904 8905 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type); 8906 } 8907 static DEVICE_ATTR_RO(type); 8908 8909 static ssize_t 8910 perf_event_mux_interval_ms_show(struct device *dev, 8911 struct device_attribute *attr, 8912 char *page) 8913 { 8914 struct pmu *pmu = dev_get_drvdata(dev); 8915 8916 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms); 8917 } 8918 8919 static DEFINE_MUTEX(mux_interval_mutex); 8920 8921 static ssize_t 8922 perf_event_mux_interval_ms_store(struct device *dev, 8923 struct device_attribute *attr, 8924 const char *buf, size_t count) 8925 { 8926 struct pmu *pmu = dev_get_drvdata(dev); 8927 int timer, cpu, ret; 8928 8929 ret = kstrtoint(buf, 0, &timer); 8930 if (ret) 8931 return ret; 8932 8933 if (timer < 1) 8934 return -EINVAL; 8935 8936 /* same value, noting to do */ 8937 if (timer == pmu->hrtimer_interval_ms) 8938 return count; 8939 8940 mutex_lock(&mux_interval_mutex); 8941 pmu->hrtimer_interval_ms = timer; 8942 8943 /* update all cpuctx for this PMU */ 8944 cpus_read_lock(); 8945 for_each_online_cpu(cpu) { 8946 struct perf_cpu_context *cpuctx; 8947 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 8948 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer); 8949 8950 cpu_function_call(cpu, 8951 (remote_function_f)perf_mux_hrtimer_restart, cpuctx); 8952 } 8953 cpus_read_unlock(); 8954 mutex_unlock(&mux_interval_mutex); 8955 8956 return count; 8957 } 8958 static DEVICE_ATTR_RW(perf_event_mux_interval_ms); 8959 8960 static struct attribute *pmu_dev_attrs[] = { 8961 &dev_attr_type.attr, 8962 &dev_attr_perf_event_mux_interval_ms.attr, 8963 NULL, 8964 }; 8965 ATTRIBUTE_GROUPS(pmu_dev); 8966 8967 static int pmu_bus_running; 8968 static struct bus_type pmu_bus = { 8969 .name = "event_source", 8970 .dev_groups = pmu_dev_groups, 8971 }; 8972 8973 static void pmu_dev_release(struct device *dev) 8974 { 8975 kfree(dev); 8976 } 8977 8978 static int pmu_dev_alloc(struct pmu *pmu) 8979 { 8980 int ret = -ENOMEM; 8981 8982 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL); 8983 if (!pmu->dev) 8984 goto out; 8985 8986 pmu->dev->groups = pmu->attr_groups; 8987 device_initialize(pmu->dev); 8988 ret = dev_set_name(pmu->dev, "%s", pmu->name); 8989 if (ret) 8990 goto free_dev; 8991 8992 dev_set_drvdata(pmu->dev, pmu); 8993 pmu->dev->bus = &pmu_bus; 8994 pmu->dev->release = pmu_dev_release; 8995 ret = device_add(pmu->dev); 8996 if (ret) 8997 goto free_dev; 8998 8999 /* For PMUs with address filters, throw in an extra attribute: */ 9000 if (pmu->nr_addr_filters) 9001 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters); 9002 9003 if (ret) 9004 goto del_dev; 9005 9006 out: 9007 return ret; 9008 9009 del_dev: 9010 device_del(pmu->dev); 9011 9012 free_dev: 9013 put_device(pmu->dev); 9014 goto out; 9015 } 9016 9017 static struct lock_class_key cpuctx_mutex; 9018 static struct lock_class_key cpuctx_lock; 9019 9020 int perf_pmu_register(struct pmu *pmu, const char *name, int type) 9021 { 9022 int cpu, ret; 9023 9024 mutex_lock(&pmus_lock); 9025 ret = -ENOMEM; 9026 pmu->pmu_disable_count = alloc_percpu(int); 9027 if (!pmu->pmu_disable_count) 9028 goto unlock; 9029 9030 pmu->type = -1; 9031 if (!name) 9032 goto skip_type; 9033 pmu->name = name; 9034 9035 if (type < 0) { 9036 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL); 9037 if (type < 0) { 9038 ret = type; 9039 goto free_pdc; 9040 } 9041 } 9042 pmu->type = type; 9043 9044 if (pmu_bus_running) { 9045 ret = pmu_dev_alloc(pmu); 9046 if (ret) 9047 goto free_idr; 9048 } 9049 9050 skip_type: 9051 if (pmu->task_ctx_nr == perf_hw_context) { 9052 static int hw_context_taken = 0; 9053 9054 /* 9055 * Other than systems with heterogeneous CPUs, it never makes 9056 * sense for two PMUs to share perf_hw_context. PMUs which are 9057 * uncore must use perf_invalid_context. 9058 */ 9059 if (WARN_ON_ONCE(hw_context_taken && 9060 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS))) 9061 pmu->task_ctx_nr = perf_invalid_context; 9062 9063 hw_context_taken = 1; 9064 } 9065 9066 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr); 9067 if (pmu->pmu_cpu_context) 9068 goto got_cpu_context; 9069 9070 ret = -ENOMEM; 9071 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context); 9072 if (!pmu->pmu_cpu_context) 9073 goto free_dev; 9074 9075 for_each_possible_cpu(cpu) { 9076 struct perf_cpu_context *cpuctx; 9077 9078 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 9079 __perf_event_init_context(&cpuctx->ctx); 9080 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex); 9081 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock); 9082 cpuctx->ctx.pmu = pmu; 9083 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask); 9084 9085 __perf_mux_hrtimer_init(cpuctx, cpu); 9086 } 9087 9088 got_cpu_context: 9089 if (!pmu->start_txn) { 9090 if (pmu->pmu_enable) { 9091 /* 9092 * If we have pmu_enable/pmu_disable calls, install 9093 * transaction stubs that use that to try and batch 9094 * hardware accesses. 9095 */ 9096 pmu->start_txn = perf_pmu_start_txn; 9097 pmu->commit_txn = perf_pmu_commit_txn; 9098 pmu->cancel_txn = perf_pmu_cancel_txn; 9099 } else { 9100 pmu->start_txn = perf_pmu_nop_txn; 9101 pmu->commit_txn = perf_pmu_nop_int; 9102 pmu->cancel_txn = perf_pmu_nop_void; 9103 } 9104 } 9105 9106 if (!pmu->pmu_enable) { 9107 pmu->pmu_enable = perf_pmu_nop_void; 9108 pmu->pmu_disable = perf_pmu_nop_void; 9109 } 9110 9111 if (!pmu->event_idx) 9112 pmu->event_idx = perf_event_idx_default; 9113 9114 list_add_rcu(&pmu->entry, &pmus); 9115 atomic_set(&pmu->exclusive_cnt, 0); 9116 ret = 0; 9117 unlock: 9118 mutex_unlock(&pmus_lock); 9119 9120 return ret; 9121 9122 free_dev: 9123 device_del(pmu->dev); 9124 put_device(pmu->dev); 9125 9126 free_idr: 9127 if (pmu->type >= PERF_TYPE_MAX) 9128 idr_remove(&pmu_idr, pmu->type); 9129 9130 free_pdc: 9131 free_percpu(pmu->pmu_disable_count); 9132 goto unlock; 9133 } 9134 EXPORT_SYMBOL_GPL(perf_pmu_register); 9135 9136 void perf_pmu_unregister(struct pmu *pmu) 9137 { 9138 int remove_device; 9139 9140 mutex_lock(&pmus_lock); 9141 remove_device = pmu_bus_running; 9142 list_del_rcu(&pmu->entry); 9143 mutex_unlock(&pmus_lock); 9144 9145 /* 9146 * We dereference the pmu list under both SRCU and regular RCU, so 9147 * synchronize against both of those. 9148 */ 9149 synchronize_srcu(&pmus_srcu); 9150 synchronize_rcu(); 9151 9152 free_percpu(pmu->pmu_disable_count); 9153 if (pmu->type >= PERF_TYPE_MAX) 9154 idr_remove(&pmu_idr, pmu->type); 9155 if (remove_device) { 9156 if (pmu->nr_addr_filters) 9157 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters); 9158 device_del(pmu->dev); 9159 put_device(pmu->dev); 9160 } 9161 free_pmu_context(pmu); 9162 } 9163 EXPORT_SYMBOL_GPL(perf_pmu_unregister); 9164 9165 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event) 9166 { 9167 struct perf_event_context *ctx = NULL; 9168 int ret; 9169 9170 if (!try_module_get(pmu->module)) 9171 return -ENODEV; 9172 9173 if (event->group_leader != event) { 9174 /* 9175 * This ctx->mutex can nest when we're called through 9176 * inheritance. See the perf_event_ctx_lock_nested() comment. 9177 */ 9178 ctx = perf_event_ctx_lock_nested(event->group_leader, 9179 SINGLE_DEPTH_NESTING); 9180 BUG_ON(!ctx); 9181 } 9182 9183 event->pmu = pmu; 9184 ret = pmu->event_init(event); 9185 9186 if (ctx) 9187 perf_event_ctx_unlock(event->group_leader, ctx); 9188 9189 if (ret) 9190 module_put(pmu->module); 9191 9192 return ret; 9193 } 9194 9195 static struct pmu *perf_init_event(struct perf_event *event) 9196 { 9197 struct pmu *pmu; 9198 int idx; 9199 int ret; 9200 9201 idx = srcu_read_lock(&pmus_srcu); 9202 9203 /* Try parent's PMU first: */ 9204 if (event->parent && event->parent->pmu) { 9205 pmu = event->parent->pmu; 9206 ret = perf_try_init_event(pmu, event); 9207 if (!ret) 9208 goto unlock; 9209 } 9210 9211 rcu_read_lock(); 9212 pmu = idr_find(&pmu_idr, event->attr.type); 9213 rcu_read_unlock(); 9214 if (pmu) { 9215 ret = perf_try_init_event(pmu, event); 9216 if (ret) 9217 pmu = ERR_PTR(ret); 9218 goto unlock; 9219 } 9220 9221 list_for_each_entry_rcu(pmu, &pmus, entry) { 9222 ret = perf_try_init_event(pmu, event); 9223 if (!ret) 9224 goto unlock; 9225 9226 if (ret != -ENOENT) { 9227 pmu = ERR_PTR(ret); 9228 goto unlock; 9229 } 9230 } 9231 pmu = ERR_PTR(-ENOENT); 9232 unlock: 9233 srcu_read_unlock(&pmus_srcu, idx); 9234 9235 return pmu; 9236 } 9237 9238 static void attach_sb_event(struct perf_event *event) 9239 { 9240 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu); 9241 9242 raw_spin_lock(&pel->lock); 9243 list_add_rcu(&event->sb_list, &pel->list); 9244 raw_spin_unlock(&pel->lock); 9245 } 9246 9247 /* 9248 * We keep a list of all !task (and therefore per-cpu) events 9249 * that need to receive side-band records. 9250 * 9251 * This avoids having to scan all the various PMU per-cpu contexts 9252 * looking for them. 9253 */ 9254 static void account_pmu_sb_event(struct perf_event *event) 9255 { 9256 if (is_sb_event(event)) 9257 attach_sb_event(event); 9258 } 9259 9260 static void account_event_cpu(struct perf_event *event, int cpu) 9261 { 9262 if (event->parent) 9263 return; 9264 9265 if (is_cgroup_event(event)) 9266 atomic_inc(&per_cpu(perf_cgroup_events, cpu)); 9267 } 9268 9269 /* Freq events need the tick to stay alive (see perf_event_task_tick). */ 9270 static void account_freq_event_nohz(void) 9271 { 9272 #ifdef CONFIG_NO_HZ_FULL 9273 /* Lock so we don't race with concurrent unaccount */ 9274 spin_lock(&nr_freq_lock); 9275 if (atomic_inc_return(&nr_freq_events) == 1) 9276 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS); 9277 spin_unlock(&nr_freq_lock); 9278 #endif 9279 } 9280 9281 static void account_freq_event(void) 9282 { 9283 if (tick_nohz_full_enabled()) 9284 account_freq_event_nohz(); 9285 else 9286 atomic_inc(&nr_freq_events); 9287 } 9288 9289 9290 static void account_event(struct perf_event *event) 9291 { 9292 bool inc = false; 9293 9294 if (event->parent) 9295 return; 9296 9297 if (event->attach_state & PERF_ATTACH_TASK) 9298 inc = true; 9299 if (event->attr.mmap || event->attr.mmap_data) 9300 atomic_inc(&nr_mmap_events); 9301 if (event->attr.comm) 9302 atomic_inc(&nr_comm_events); 9303 if (event->attr.namespaces) 9304 atomic_inc(&nr_namespaces_events); 9305 if (event->attr.task) 9306 atomic_inc(&nr_task_events); 9307 if (event->attr.freq) 9308 account_freq_event(); 9309 if (event->attr.context_switch) { 9310 atomic_inc(&nr_switch_events); 9311 inc = true; 9312 } 9313 if (has_branch_stack(event)) 9314 inc = true; 9315 if (is_cgroup_event(event)) 9316 inc = true; 9317 9318 if (inc) { 9319 if (atomic_inc_not_zero(&perf_sched_count)) 9320 goto enabled; 9321 9322 mutex_lock(&perf_sched_mutex); 9323 if (!atomic_read(&perf_sched_count)) { 9324 static_branch_enable(&perf_sched_events); 9325 /* 9326 * Guarantee that all CPUs observe they key change and 9327 * call the perf scheduling hooks before proceeding to 9328 * install events that need them. 9329 */ 9330 synchronize_sched(); 9331 } 9332 /* 9333 * Now that we have waited for the sync_sched(), allow further 9334 * increments to by-pass the mutex. 9335 */ 9336 atomic_inc(&perf_sched_count); 9337 mutex_unlock(&perf_sched_mutex); 9338 } 9339 enabled: 9340 9341 account_event_cpu(event, event->cpu); 9342 9343 account_pmu_sb_event(event); 9344 } 9345 9346 /* 9347 * Allocate and initialize a event structure 9348 */ 9349 static struct perf_event * 9350 perf_event_alloc(struct perf_event_attr *attr, int cpu, 9351 struct task_struct *task, 9352 struct perf_event *group_leader, 9353 struct perf_event *parent_event, 9354 perf_overflow_handler_t overflow_handler, 9355 void *context, int cgroup_fd) 9356 { 9357 struct pmu *pmu; 9358 struct perf_event *event; 9359 struct hw_perf_event *hwc; 9360 long err = -EINVAL; 9361 9362 if ((unsigned)cpu >= nr_cpu_ids) { 9363 if (!task || cpu != -1) 9364 return ERR_PTR(-EINVAL); 9365 } 9366 9367 event = kzalloc(sizeof(*event), GFP_KERNEL); 9368 if (!event) 9369 return ERR_PTR(-ENOMEM); 9370 9371 /* 9372 * Single events are their own group leaders, with an 9373 * empty sibling list: 9374 */ 9375 if (!group_leader) 9376 group_leader = event; 9377 9378 mutex_init(&event->child_mutex); 9379 INIT_LIST_HEAD(&event->child_list); 9380 9381 INIT_LIST_HEAD(&event->group_entry); 9382 INIT_LIST_HEAD(&event->event_entry); 9383 INIT_LIST_HEAD(&event->sibling_list); 9384 INIT_LIST_HEAD(&event->rb_entry); 9385 INIT_LIST_HEAD(&event->active_entry); 9386 INIT_LIST_HEAD(&event->addr_filters.list); 9387 INIT_HLIST_NODE(&event->hlist_entry); 9388 9389 9390 init_waitqueue_head(&event->waitq); 9391 init_irq_work(&event->pending, perf_pending_event); 9392 9393 mutex_init(&event->mmap_mutex); 9394 raw_spin_lock_init(&event->addr_filters.lock); 9395 9396 atomic_long_set(&event->refcount, 1); 9397 event->cpu = cpu; 9398 event->attr = *attr; 9399 event->group_leader = group_leader; 9400 event->pmu = NULL; 9401 event->oncpu = -1; 9402 9403 event->parent = parent_event; 9404 9405 event->ns = get_pid_ns(task_active_pid_ns(current)); 9406 event->id = atomic64_inc_return(&perf_event_id); 9407 9408 event->state = PERF_EVENT_STATE_INACTIVE; 9409 9410 if (task) { 9411 event->attach_state = PERF_ATTACH_TASK; 9412 /* 9413 * XXX pmu::event_init needs to know what task to account to 9414 * and we cannot use the ctx information because we need the 9415 * pmu before we get a ctx. 9416 */ 9417 event->hw.target = task; 9418 } 9419 9420 event->clock = &local_clock; 9421 if (parent_event) 9422 event->clock = parent_event->clock; 9423 9424 if (!overflow_handler && parent_event) { 9425 overflow_handler = parent_event->overflow_handler; 9426 context = parent_event->overflow_handler_context; 9427 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING) 9428 if (overflow_handler == bpf_overflow_handler) { 9429 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog); 9430 9431 if (IS_ERR(prog)) { 9432 err = PTR_ERR(prog); 9433 goto err_ns; 9434 } 9435 event->prog = prog; 9436 event->orig_overflow_handler = 9437 parent_event->orig_overflow_handler; 9438 } 9439 #endif 9440 } 9441 9442 if (overflow_handler) { 9443 event->overflow_handler = overflow_handler; 9444 event->overflow_handler_context = context; 9445 } else if (is_write_backward(event)){ 9446 event->overflow_handler = perf_event_output_backward; 9447 event->overflow_handler_context = NULL; 9448 } else { 9449 event->overflow_handler = perf_event_output_forward; 9450 event->overflow_handler_context = NULL; 9451 } 9452 9453 perf_event__state_init(event); 9454 9455 pmu = NULL; 9456 9457 hwc = &event->hw; 9458 hwc->sample_period = attr->sample_period; 9459 if (attr->freq && attr->sample_freq) 9460 hwc->sample_period = 1; 9461 hwc->last_period = hwc->sample_period; 9462 9463 local64_set(&hwc->period_left, hwc->sample_period); 9464 9465 /* 9466 * We currently do not support PERF_SAMPLE_READ on inherited events. 9467 * See perf_output_read(). 9468 */ 9469 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ)) 9470 goto err_ns; 9471 9472 if (!has_branch_stack(event)) 9473 event->attr.branch_sample_type = 0; 9474 9475 if (cgroup_fd != -1) { 9476 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader); 9477 if (err) 9478 goto err_ns; 9479 } 9480 9481 pmu = perf_init_event(event); 9482 if (IS_ERR(pmu)) { 9483 err = PTR_ERR(pmu); 9484 goto err_ns; 9485 } 9486 9487 err = exclusive_event_init(event); 9488 if (err) 9489 goto err_pmu; 9490 9491 if (has_addr_filter(event)) { 9492 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters, 9493 sizeof(unsigned long), 9494 GFP_KERNEL); 9495 if (!event->addr_filters_offs) { 9496 err = -ENOMEM; 9497 goto err_per_task; 9498 } 9499 9500 /* force hw sync on the address filters */ 9501 event->addr_filters_gen = 1; 9502 } 9503 9504 if (!event->parent) { 9505 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) { 9506 err = get_callchain_buffers(attr->sample_max_stack); 9507 if (err) 9508 goto err_addr_filters; 9509 } 9510 } 9511 9512 /* symmetric to unaccount_event() in _free_event() */ 9513 account_event(event); 9514 9515 return event; 9516 9517 err_addr_filters: 9518 kfree(event->addr_filters_offs); 9519 9520 err_per_task: 9521 exclusive_event_destroy(event); 9522 9523 err_pmu: 9524 if (event->destroy) 9525 event->destroy(event); 9526 module_put(pmu->module); 9527 err_ns: 9528 if (is_cgroup_event(event)) 9529 perf_detach_cgroup(event); 9530 if (event->ns) 9531 put_pid_ns(event->ns); 9532 kfree(event); 9533 9534 return ERR_PTR(err); 9535 } 9536 9537 static int perf_copy_attr(struct perf_event_attr __user *uattr, 9538 struct perf_event_attr *attr) 9539 { 9540 u32 size; 9541 int ret; 9542 9543 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0)) 9544 return -EFAULT; 9545 9546 /* 9547 * zero the full structure, so that a short copy will be nice. 9548 */ 9549 memset(attr, 0, sizeof(*attr)); 9550 9551 ret = get_user(size, &uattr->size); 9552 if (ret) 9553 return ret; 9554 9555 if (size > PAGE_SIZE) /* silly large */ 9556 goto err_size; 9557 9558 if (!size) /* abi compat */ 9559 size = PERF_ATTR_SIZE_VER0; 9560 9561 if (size < PERF_ATTR_SIZE_VER0) 9562 goto err_size; 9563 9564 /* 9565 * If we're handed a bigger struct than we know of, 9566 * ensure all the unknown bits are 0 - i.e. new 9567 * user-space does not rely on any kernel feature 9568 * extensions we dont know about yet. 9569 */ 9570 if (size > sizeof(*attr)) { 9571 unsigned char __user *addr; 9572 unsigned char __user *end; 9573 unsigned char val; 9574 9575 addr = (void __user *)uattr + sizeof(*attr); 9576 end = (void __user *)uattr + size; 9577 9578 for (; addr < end; addr++) { 9579 ret = get_user(val, addr); 9580 if (ret) 9581 return ret; 9582 if (val) 9583 goto err_size; 9584 } 9585 size = sizeof(*attr); 9586 } 9587 9588 ret = copy_from_user(attr, uattr, size); 9589 if (ret) 9590 return -EFAULT; 9591 9592 if (attr->__reserved_1) 9593 return -EINVAL; 9594 9595 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1)) 9596 return -EINVAL; 9597 9598 if (attr->read_format & ~(PERF_FORMAT_MAX-1)) 9599 return -EINVAL; 9600 9601 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) { 9602 u64 mask = attr->branch_sample_type; 9603 9604 /* only using defined bits */ 9605 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1)) 9606 return -EINVAL; 9607 9608 /* at least one branch bit must be set */ 9609 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL)) 9610 return -EINVAL; 9611 9612 /* propagate priv level, when not set for branch */ 9613 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) { 9614 9615 /* exclude_kernel checked on syscall entry */ 9616 if (!attr->exclude_kernel) 9617 mask |= PERF_SAMPLE_BRANCH_KERNEL; 9618 9619 if (!attr->exclude_user) 9620 mask |= PERF_SAMPLE_BRANCH_USER; 9621 9622 if (!attr->exclude_hv) 9623 mask |= PERF_SAMPLE_BRANCH_HV; 9624 /* 9625 * adjust user setting (for HW filter setup) 9626 */ 9627 attr->branch_sample_type = mask; 9628 } 9629 /* privileged levels capture (kernel, hv): check permissions */ 9630 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM) 9631 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) 9632 return -EACCES; 9633 } 9634 9635 if (attr->sample_type & PERF_SAMPLE_REGS_USER) { 9636 ret = perf_reg_validate(attr->sample_regs_user); 9637 if (ret) 9638 return ret; 9639 } 9640 9641 if (attr->sample_type & PERF_SAMPLE_STACK_USER) { 9642 if (!arch_perf_have_user_stack_dump()) 9643 return -ENOSYS; 9644 9645 /* 9646 * We have __u32 type for the size, but so far 9647 * we can only use __u16 as maximum due to the 9648 * __u16 sample size limit. 9649 */ 9650 if (attr->sample_stack_user >= USHRT_MAX) 9651 ret = -EINVAL; 9652 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64))) 9653 ret = -EINVAL; 9654 } 9655 9656 if (attr->sample_type & PERF_SAMPLE_REGS_INTR) 9657 ret = perf_reg_validate(attr->sample_regs_intr); 9658 out: 9659 return ret; 9660 9661 err_size: 9662 put_user(sizeof(*attr), &uattr->size); 9663 ret = -E2BIG; 9664 goto out; 9665 } 9666 9667 static int 9668 perf_event_set_output(struct perf_event *event, struct perf_event *output_event) 9669 { 9670 struct ring_buffer *rb = NULL; 9671 int ret = -EINVAL; 9672 9673 if (!output_event) 9674 goto set; 9675 9676 /* don't allow circular references */ 9677 if (event == output_event) 9678 goto out; 9679 9680 /* 9681 * Don't allow cross-cpu buffers 9682 */ 9683 if (output_event->cpu != event->cpu) 9684 goto out; 9685 9686 /* 9687 * If its not a per-cpu rb, it must be the same task. 9688 */ 9689 if (output_event->cpu == -1 && output_event->ctx != event->ctx) 9690 goto out; 9691 9692 /* 9693 * Mixing clocks in the same buffer is trouble you don't need. 9694 */ 9695 if (output_event->clock != event->clock) 9696 goto out; 9697 9698 /* 9699 * Either writing ring buffer from beginning or from end. 9700 * Mixing is not allowed. 9701 */ 9702 if (is_write_backward(output_event) != is_write_backward(event)) 9703 goto out; 9704 9705 /* 9706 * If both events generate aux data, they must be on the same PMU 9707 */ 9708 if (has_aux(event) && has_aux(output_event) && 9709 event->pmu != output_event->pmu) 9710 goto out; 9711 9712 set: 9713 mutex_lock(&event->mmap_mutex); 9714 /* Can't redirect output if we've got an active mmap() */ 9715 if (atomic_read(&event->mmap_count)) 9716 goto unlock; 9717 9718 if (output_event) { 9719 /* get the rb we want to redirect to */ 9720 rb = ring_buffer_get(output_event); 9721 if (!rb) 9722 goto unlock; 9723 } 9724 9725 ring_buffer_attach(event, rb); 9726 9727 ret = 0; 9728 unlock: 9729 mutex_unlock(&event->mmap_mutex); 9730 9731 out: 9732 return ret; 9733 } 9734 9735 static void mutex_lock_double(struct mutex *a, struct mutex *b) 9736 { 9737 if (b < a) 9738 swap(a, b); 9739 9740 mutex_lock(a); 9741 mutex_lock_nested(b, SINGLE_DEPTH_NESTING); 9742 } 9743 9744 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id) 9745 { 9746 bool nmi_safe = false; 9747 9748 switch (clk_id) { 9749 case CLOCK_MONOTONIC: 9750 event->clock = &ktime_get_mono_fast_ns; 9751 nmi_safe = true; 9752 break; 9753 9754 case CLOCK_MONOTONIC_RAW: 9755 event->clock = &ktime_get_raw_fast_ns; 9756 nmi_safe = true; 9757 break; 9758 9759 case CLOCK_REALTIME: 9760 event->clock = &ktime_get_real_ns; 9761 break; 9762 9763 case CLOCK_BOOTTIME: 9764 event->clock = &ktime_get_boot_ns; 9765 break; 9766 9767 case CLOCK_TAI: 9768 event->clock = &ktime_get_tai_ns; 9769 break; 9770 9771 default: 9772 return -EINVAL; 9773 } 9774 9775 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI)) 9776 return -EINVAL; 9777 9778 return 0; 9779 } 9780 9781 /* 9782 * Variation on perf_event_ctx_lock_nested(), except we take two context 9783 * mutexes. 9784 */ 9785 static struct perf_event_context * 9786 __perf_event_ctx_lock_double(struct perf_event *group_leader, 9787 struct perf_event_context *ctx) 9788 { 9789 struct perf_event_context *gctx; 9790 9791 again: 9792 rcu_read_lock(); 9793 gctx = READ_ONCE(group_leader->ctx); 9794 if (!atomic_inc_not_zero(&gctx->refcount)) { 9795 rcu_read_unlock(); 9796 goto again; 9797 } 9798 rcu_read_unlock(); 9799 9800 mutex_lock_double(&gctx->mutex, &ctx->mutex); 9801 9802 if (group_leader->ctx != gctx) { 9803 mutex_unlock(&ctx->mutex); 9804 mutex_unlock(&gctx->mutex); 9805 put_ctx(gctx); 9806 goto again; 9807 } 9808 9809 return gctx; 9810 } 9811 9812 /** 9813 * sys_perf_event_open - open a performance event, associate it to a task/cpu 9814 * 9815 * @attr_uptr: event_id type attributes for monitoring/sampling 9816 * @pid: target pid 9817 * @cpu: target cpu 9818 * @group_fd: group leader event fd 9819 */ 9820 SYSCALL_DEFINE5(perf_event_open, 9821 struct perf_event_attr __user *, attr_uptr, 9822 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags) 9823 { 9824 struct perf_event *group_leader = NULL, *output_event = NULL; 9825 struct perf_event *event, *sibling; 9826 struct perf_event_attr attr; 9827 struct perf_event_context *ctx, *uninitialized_var(gctx); 9828 struct file *event_file = NULL; 9829 struct fd group = {NULL, 0}; 9830 struct task_struct *task = NULL; 9831 struct pmu *pmu; 9832 int event_fd; 9833 int move_group = 0; 9834 int err; 9835 int f_flags = O_RDWR; 9836 int cgroup_fd = -1; 9837 9838 /* for future expandability... */ 9839 if (flags & ~PERF_FLAG_ALL) 9840 return -EINVAL; 9841 9842 err = perf_copy_attr(attr_uptr, &attr); 9843 if (err) 9844 return err; 9845 9846 if (!attr.exclude_kernel) { 9847 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) 9848 return -EACCES; 9849 } 9850 9851 if (attr.namespaces) { 9852 if (!capable(CAP_SYS_ADMIN)) 9853 return -EACCES; 9854 } 9855 9856 if (attr.freq) { 9857 if (attr.sample_freq > sysctl_perf_event_sample_rate) 9858 return -EINVAL; 9859 } else { 9860 if (attr.sample_period & (1ULL << 63)) 9861 return -EINVAL; 9862 } 9863 9864 if (!attr.sample_max_stack) 9865 attr.sample_max_stack = sysctl_perf_event_max_stack; 9866 9867 /* 9868 * In cgroup mode, the pid argument is used to pass the fd 9869 * opened to the cgroup directory in cgroupfs. The cpu argument 9870 * designates the cpu on which to monitor threads from that 9871 * cgroup. 9872 */ 9873 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1)) 9874 return -EINVAL; 9875 9876 if (flags & PERF_FLAG_FD_CLOEXEC) 9877 f_flags |= O_CLOEXEC; 9878 9879 event_fd = get_unused_fd_flags(f_flags); 9880 if (event_fd < 0) 9881 return event_fd; 9882 9883 if (group_fd != -1) { 9884 err = perf_fget_light(group_fd, &group); 9885 if (err) 9886 goto err_fd; 9887 group_leader = group.file->private_data; 9888 if (flags & PERF_FLAG_FD_OUTPUT) 9889 output_event = group_leader; 9890 if (flags & PERF_FLAG_FD_NO_GROUP) 9891 group_leader = NULL; 9892 } 9893 9894 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) { 9895 task = find_lively_task_by_vpid(pid); 9896 if (IS_ERR(task)) { 9897 err = PTR_ERR(task); 9898 goto err_group_fd; 9899 } 9900 } 9901 9902 if (task && group_leader && 9903 group_leader->attr.inherit != attr.inherit) { 9904 err = -EINVAL; 9905 goto err_task; 9906 } 9907 9908 if (task) { 9909 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex); 9910 if (err) 9911 goto err_task; 9912 9913 /* 9914 * Reuse ptrace permission checks for now. 9915 * 9916 * We must hold cred_guard_mutex across this and any potential 9917 * perf_install_in_context() call for this new event to 9918 * serialize against exec() altering our credentials (and the 9919 * perf_event_exit_task() that could imply). 9920 */ 9921 err = -EACCES; 9922 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) 9923 goto err_cred; 9924 } 9925 9926 if (flags & PERF_FLAG_PID_CGROUP) 9927 cgroup_fd = pid; 9928 9929 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, 9930 NULL, NULL, cgroup_fd); 9931 if (IS_ERR(event)) { 9932 err = PTR_ERR(event); 9933 goto err_cred; 9934 } 9935 9936 if (is_sampling_event(event)) { 9937 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) { 9938 err = -EOPNOTSUPP; 9939 goto err_alloc; 9940 } 9941 } 9942 9943 /* 9944 * Special case software events and allow them to be part of 9945 * any hardware group. 9946 */ 9947 pmu = event->pmu; 9948 9949 if (attr.use_clockid) { 9950 err = perf_event_set_clock(event, attr.clockid); 9951 if (err) 9952 goto err_alloc; 9953 } 9954 9955 if (pmu->task_ctx_nr == perf_sw_context) 9956 event->event_caps |= PERF_EV_CAP_SOFTWARE; 9957 9958 if (group_leader && 9959 (is_software_event(event) != is_software_event(group_leader))) { 9960 if (is_software_event(event)) { 9961 /* 9962 * If event and group_leader are not both a software 9963 * event, and event is, then group leader is not. 9964 * 9965 * Allow the addition of software events to !software 9966 * groups, this is safe because software events never 9967 * fail to schedule. 9968 */ 9969 pmu = group_leader->pmu; 9970 } else if (is_software_event(group_leader) && 9971 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) { 9972 /* 9973 * In case the group is a pure software group, and we 9974 * try to add a hardware event, move the whole group to 9975 * the hardware context. 9976 */ 9977 move_group = 1; 9978 } 9979 } 9980 9981 /* 9982 * Get the target context (task or percpu): 9983 */ 9984 ctx = find_get_context(pmu, task, event); 9985 if (IS_ERR(ctx)) { 9986 err = PTR_ERR(ctx); 9987 goto err_alloc; 9988 } 9989 9990 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) { 9991 err = -EBUSY; 9992 goto err_context; 9993 } 9994 9995 /* 9996 * Look up the group leader (we will attach this event to it): 9997 */ 9998 if (group_leader) { 9999 err = -EINVAL; 10000 10001 /* 10002 * Do not allow a recursive hierarchy (this new sibling 10003 * becoming part of another group-sibling): 10004 */ 10005 if (group_leader->group_leader != group_leader) 10006 goto err_context; 10007 10008 /* All events in a group should have the same clock */ 10009 if (group_leader->clock != event->clock) 10010 goto err_context; 10011 10012 /* 10013 * Do not allow to attach to a group in a different 10014 * task or CPU context: 10015 */ 10016 if (move_group) { 10017 /* 10018 * Make sure we're both on the same task, or both 10019 * per-cpu events. 10020 */ 10021 if (group_leader->ctx->task != ctx->task) 10022 goto err_context; 10023 10024 /* 10025 * Make sure we're both events for the same CPU; 10026 * grouping events for different CPUs is broken; since 10027 * you can never concurrently schedule them anyhow. 10028 */ 10029 if (group_leader->cpu != event->cpu) 10030 goto err_context; 10031 } else { 10032 if (group_leader->ctx != ctx) 10033 goto err_context; 10034 } 10035 10036 /* 10037 * Only a group leader can be exclusive or pinned 10038 */ 10039 if (attr.exclusive || attr.pinned) 10040 goto err_context; 10041 } 10042 10043 if (output_event) { 10044 err = perf_event_set_output(event, output_event); 10045 if (err) 10046 goto err_context; 10047 } 10048 10049 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, 10050 f_flags); 10051 if (IS_ERR(event_file)) { 10052 err = PTR_ERR(event_file); 10053 event_file = NULL; 10054 goto err_context; 10055 } 10056 10057 if (move_group) { 10058 gctx = __perf_event_ctx_lock_double(group_leader, ctx); 10059 10060 if (gctx->task == TASK_TOMBSTONE) { 10061 err = -ESRCH; 10062 goto err_locked; 10063 } 10064 10065 /* 10066 * Check if we raced against another sys_perf_event_open() call 10067 * moving the software group underneath us. 10068 */ 10069 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) { 10070 /* 10071 * If someone moved the group out from under us, check 10072 * if this new event wound up on the same ctx, if so 10073 * its the regular !move_group case, otherwise fail. 10074 */ 10075 if (gctx != ctx) { 10076 err = -EINVAL; 10077 goto err_locked; 10078 } else { 10079 perf_event_ctx_unlock(group_leader, gctx); 10080 move_group = 0; 10081 } 10082 } 10083 } else { 10084 mutex_lock(&ctx->mutex); 10085 } 10086 10087 if (ctx->task == TASK_TOMBSTONE) { 10088 err = -ESRCH; 10089 goto err_locked; 10090 } 10091 10092 if (!perf_event_validate_size(event)) { 10093 err = -E2BIG; 10094 goto err_locked; 10095 } 10096 10097 if (!task) { 10098 /* 10099 * Check if the @cpu we're creating an event for is online. 10100 * 10101 * We use the perf_cpu_context::ctx::mutex to serialize against 10102 * the hotplug notifiers. See perf_event_{init,exit}_cpu(). 10103 */ 10104 struct perf_cpu_context *cpuctx = 10105 container_of(ctx, struct perf_cpu_context, ctx); 10106 10107 if (!cpuctx->online) { 10108 err = -ENODEV; 10109 goto err_locked; 10110 } 10111 } 10112 10113 10114 /* 10115 * Must be under the same ctx::mutex as perf_install_in_context(), 10116 * because we need to serialize with concurrent event creation. 10117 */ 10118 if (!exclusive_event_installable(event, ctx)) { 10119 /* exclusive and group stuff are assumed mutually exclusive */ 10120 WARN_ON_ONCE(move_group); 10121 10122 err = -EBUSY; 10123 goto err_locked; 10124 } 10125 10126 WARN_ON_ONCE(ctx->parent_ctx); 10127 10128 /* 10129 * This is the point on no return; we cannot fail hereafter. This is 10130 * where we start modifying current state. 10131 */ 10132 10133 if (move_group) { 10134 /* 10135 * See perf_event_ctx_lock() for comments on the details 10136 * of swizzling perf_event::ctx. 10137 */ 10138 perf_remove_from_context(group_leader, 0); 10139 put_ctx(gctx); 10140 10141 list_for_each_entry(sibling, &group_leader->sibling_list, 10142 group_entry) { 10143 perf_remove_from_context(sibling, 0); 10144 put_ctx(gctx); 10145 } 10146 10147 /* 10148 * Wait for everybody to stop referencing the events through 10149 * the old lists, before installing it on new lists. 10150 */ 10151 synchronize_rcu(); 10152 10153 /* 10154 * Install the group siblings before the group leader. 10155 * 10156 * Because a group leader will try and install the entire group 10157 * (through the sibling list, which is still in-tact), we can 10158 * end up with siblings installed in the wrong context. 10159 * 10160 * By installing siblings first we NO-OP because they're not 10161 * reachable through the group lists. 10162 */ 10163 list_for_each_entry(sibling, &group_leader->sibling_list, 10164 group_entry) { 10165 perf_event__state_init(sibling); 10166 perf_install_in_context(ctx, sibling, sibling->cpu); 10167 get_ctx(ctx); 10168 } 10169 10170 /* 10171 * Removing from the context ends up with disabled 10172 * event. What we want here is event in the initial 10173 * startup state, ready to be add into new context. 10174 */ 10175 perf_event__state_init(group_leader); 10176 perf_install_in_context(ctx, group_leader, group_leader->cpu); 10177 get_ctx(ctx); 10178 } 10179 10180 /* 10181 * Precalculate sample_data sizes; do while holding ctx::mutex such 10182 * that we're serialized against further additions and before 10183 * perf_install_in_context() which is the point the event is active and 10184 * can use these values. 10185 */ 10186 perf_event__header_size(event); 10187 perf_event__id_header_size(event); 10188 10189 event->owner = current; 10190 10191 perf_install_in_context(ctx, event, event->cpu); 10192 perf_unpin_context(ctx); 10193 10194 if (move_group) 10195 perf_event_ctx_unlock(group_leader, gctx); 10196 mutex_unlock(&ctx->mutex); 10197 10198 if (task) { 10199 mutex_unlock(&task->signal->cred_guard_mutex); 10200 put_task_struct(task); 10201 } 10202 10203 mutex_lock(¤t->perf_event_mutex); 10204 list_add_tail(&event->owner_entry, ¤t->perf_event_list); 10205 mutex_unlock(¤t->perf_event_mutex); 10206 10207 /* 10208 * Drop the reference on the group_event after placing the 10209 * new event on the sibling_list. This ensures destruction 10210 * of the group leader will find the pointer to itself in 10211 * perf_group_detach(). 10212 */ 10213 fdput(group); 10214 fd_install(event_fd, event_file); 10215 return event_fd; 10216 10217 err_locked: 10218 if (move_group) 10219 perf_event_ctx_unlock(group_leader, gctx); 10220 mutex_unlock(&ctx->mutex); 10221 /* err_file: */ 10222 fput(event_file); 10223 err_context: 10224 perf_unpin_context(ctx); 10225 put_ctx(ctx); 10226 err_alloc: 10227 /* 10228 * If event_file is set, the fput() above will have called ->release() 10229 * and that will take care of freeing the event. 10230 */ 10231 if (!event_file) 10232 free_event(event); 10233 err_cred: 10234 if (task) 10235 mutex_unlock(&task->signal->cred_guard_mutex); 10236 err_task: 10237 if (task) 10238 put_task_struct(task); 10239 err_group_fd: 10240 fdput(group); 10241 err_fd: 10242 put_unused_fd(event_fd); 10243 return err; 10244 } 10245 10246 /** 10247 * perf_event_create_kernel_counter 10248 * 10249 * @attr: attributes of the counter to create 10250 * @cpu: cpu in which the counter is bound 10251 * @task: task to profile (NULL for percpu) 10252 */ 10253 struct perf_event * 10254 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, 10255 struct task_struct *task, 10256 perf_overflow_handler_t overflow_handler, 10257 void *context) 10258 { 10259 struct perf_event_context *ctx; 10260 struct perf_event *event; 10261 int err; 10262 10263 /* 10264 * Get the target context (task or percpu): 10265 */ 10266 10267 event = perf_event_alloc(attr, cpu, task, NULL, NULL, 10268 overflow_handler, context, -1); 10269 if (IS_ERR(event)) { 10270 err = PTR_ERR(event); 10271 goto err; 10272 } 10273 10274 /* Mark owner so we could distinguish it from user events. */ 10275 event->owner = TASK_TOMBSTONE; 10276 10277 ctx = find_get_context(event->pmu, task, event); 10278 if (IS_ERR(ctx)) { 10279 err = PTR_ERR(ctx); 10280 goto err_free; 10281 } 10282 10283 WARN_ON_ONCE(ctx->parent_ctx); 10284 mutex_lock(&ctx->mutex); 10285 if (ctx->task == TASK_TOMBSTONE) { 10286 err = -ESRCH; 10287 goto err_unlock; 10288 } 10289 10290 if (!task) { 10291 /* 10292 * Check if the @cpu we're creating an event for is online. 10293 * 10294 * We use the perf_cpu_context::ctx::mutex to serialize against 10295 * the hotplug notifiers. See perf_event_{init,exit}_cpu(). 10296 */ 10297 struct perf_cpu_context *cpuctx = 10298 container_of(ctx, struct perf_cpu_context, ctx); 10299 if (!cpuctx->online) { 10300 err = -ENODEV; 10301 goto err_unlock; 10302 } 10303 } 10304 10305 if (!exclusive_event_installable(event, ctx)) { 10306 err = -EBUSY; 10307 goto err_unlock; 10308 } 10309 10310 perf_install_in_context(ctx, event, cpu); 10311 perf_unpin_context(ctx); 10312 mutex_unlock(&ctx->mutex); 10313 10314 return event; 10315 10316 err_unlock: 10317 mutex_unlock(&ctx->mutex); 10318 perf_unpin_context(ctx); 10319 put_ctx(ctx); 10320 err_free: 10321 free_event(event); 10322 err: 10323 return ERR_PTR(err); 10324 } 10325 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter); 10326 10327 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu) 10328 { 10329 struct perf_event_context *src_ctx; 10330 struct perf_event_context *dst_ctx; 10331 struct perf_event *event, *tmp; 10332 LIST_HEAD(events); 10333 10334 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx; 10335 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx; 10336 10337 /* 10338 * See perf_event_ctx_lock() for comments on the details 10339 * of swizzling perf_event::ctx. 10340 */ 10341 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex); 10342 list_for_each_entry_safe(event, tmp, &src_ctx->event_list, 10343 event_entry) { 10344 perf_remove_from_context(event, 0); 10345 unaccount_event_cpu(event, src_cpu); 10346 put_ctx(src_ctx); 10347 list_add(&event->migrate_entry, &events); 10348 } 10349 10350 /* 10351 * Wait for the events to quiesce before re-instating them. 10352 */ 10353 synchronize_rcu(); 10354 10355 /* 10356 * Re-instate events in 2 passes. 10357 * 10358 * Skip over group leaders and only install siblings on this first 10359 * pass, siblings will not get enabled without a leader, however a 10360 * leader will enable its siblings, even if those are still on the old 10361 * context. 10362 */ 10363 list_for_each_entry_safe(event, tmp, &events, migrate_entry) { 10364 if (event->group_leader == event) 10365 continue; 10366 10367 list_del(&event->migrate_entry); 10368 if (event->state >= PERF_EVENT_STATE_OFF) 10369 event->state = PERF_EVENT_STATE_INACTIVE; 10370 account_event_cpu(event, dst_cpu); 10371 perf_install_in_context(dst_ctx, event, dst_cpu); 10372 get_ctx(dst_ctx); 10373 } 10374 10375 /* 10376 * Once all the siblings are setup properly, install the group leaders 10377 * to make it go. 10378 */ 10379 list_for_each_entry_safe(event, tmp, &events, migrate_entry) { 10380 list_del(&event->migrate_entry); 10381 if (event->state >= PERF_EVENT_STATE_OFF) 10382 event->state = PERF_EVENT_STATE_INACTIVE; 10383 account_event_cpu(event, dst_cpu); 10384 perf_install_in_context(dst_ctx, event, dst_cpu); 10385 get_ctx(dst_ctx); 10386 } 10387 mutex_unlock(&dst_ctx->mutex); 10388 mutex_unlock(&src_ctx->mutex); 10389 } 10390 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context); 10391 10392 static void sync_child_event(struct perf_event *child_event, 10393 struct task_struct *child) 10394 { 10395 struct perf_event *parent_event = child_event->parent; 10396 u64 child_val; 10397 10398 if (child_event->attr.inherit_stat) 10399 perf_event_read_event(child_event, child); 10400 10401 child_val = perf_event_count(child_event); 10402 10403 /* 10404 * Add back the child's count to the parent's count: 10405 */ 10406 atomic64_add(child_val, &parent_event->child_count); 10407 atomic64_add(child_event->total_time_enabled, 10408 &parent_event->child_total_time_enabled); 10409 atomic64_add(child_event->total_time_running, 10410 &parent_event->child_total_time_running); 10411 } 10412 10413 static void 10414 perf_event_exit_event(struct perf_event *child_event, 10415 struct perf_event_context *child_ctx, 10416 struct task_struct *child) 10417 { 10418 struct perf_event *parent_event = child_event->parent; 10419 10420 /* 10421 * Do not destroy the 'original' grouping; because of the context 10422 * switch optimization the original events could've ended up in a 10423 * random child task. 10424 * 10425 * If we were to destroy the original group, all group related 10426 * operations would cease to function properly after this random 10427 * child dies. 10428 * 10429 * Do destroy all inherited groups, we don't care about those 10430 * and being thorough is better. 10431 */ 10432 raw_spin_lock_irq(&child_ctx->lock); 10433 WARN_ON_ONCE(child_ctx->is_active); 10434 10435 if (parent_event) 10436 perf_group_detach(child_event); 10437 list_del_event(child_event, child_ctx); 10438 child_event->state = PERF_EVENT_STATE_EXIT; /* is_event_hup() */ 10439 raw_spin_unlock_irq(&child_ctx->lock); 10440 10441 /* 10442 * Parent events are governed by their filedesc, retain them. 10443 */ 10444 if (!parent_event) { 10445 perf_event_wakeup(child_event); 10446 return; 10447 } 10448 /* 10449 * Child events can be cleaned up. 10450 */ 10451 10452 sync_child_event(child_event, child); 10453 10454 /* 10455 * Remove this event from the parent's list 10456 */ 10457 WARN_ON_ONCE(parent_event->ctx->parent_ctx); 10458 mutex_lock(&parent_event->child_mutex); 10459 list_del_init(&child_event->child_list); 10460 mutex_unlock(&parent_event->child_mutex); 10461 10462 /* 10463 * Kick perf_poll() for is_event_hup(). 10464 */ 10465 perf_event_wakeup(parent_event); 10466 free_event(child_event); 10467 put_event(parent_event); 10468 } 10469 10470 static void perf_event_exit_task_context(struct task_struct *child, int ctxn) 10471 { 10472 struct perf_event_context *child_ctx, *clone_ctx = NULL; 10473 struct perf_event *child_event, *next; 10474 10475 WARN_ON_ONCE(child != current); 10476 10477 child_ctx = perf_pin_task_context(child, ctxn); 10478 if (!child_ctx) 10479 return; 10480 10481 /* 10482 * In order to reduce the amount of tricky in ctx tear-down, we hold 10483 * ctx::mutex over the entire thing. This serializes against almost 10484 * everything that wants to access the ctx. 10485 * 10486 * The exception is sys_perf_event_open() / 10487 * perf_event_create_kernel_count() which does find_get_context() 10488 * without ctx::mutex (it cannot because of the move_group double mutex 10489 * lock thing). See the comments in perf_install_in_context(). 10490 */ 10491 mutex_lock(&child_ctx->mutex); 10492 10493 /* 10494 * In a single ctx::lock section, de-schedule the events and detach the 10495 * context from the task such that we cannot ever get it scheduled back 10496 * in. 10497 */ 10498 raw_spin_lock_irq(&child_ctx->lock); 10499 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL); 10500 10501 /* 10502 * Now that the context is inactive, destroy the task <-> ctx relation 10503 * and mark the context dead. 10504 */ 10505 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL); 10506 put_ctx(child_ctx); /* cannot be last */ 10507 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE); 10508 put_task_struct(current); /* cannot be last */ 10509 10510 clone_ctx = unclone_ctx(child_ctx); 10511 raw_spin_unlock_irq(&child_ctx->lock); 10512 10513 if (clone_ctx) 10514 put_ctx(clone_ctx); 10515 10516 /* 10517 * Report the task dead after unscheduling the events so that we 10518 * won't get any samples after PERF_RECORD_EXIT. We can however still 10519 * get a few PERF_RECORD_READ events. 10520 */ 10521 perf_event_task(child, child_ctx, 0); 10522 10523 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry) 10524 perf_event_exit_event(child_event, child_ctx, child); 10525 10526 mutex_unlock(&child_ctx->mutex); 10527 10528 put_ctx(child_ctx); 10529 } 10530 10531 /* 10532 * When a child task exits, feed back event values to parent events. 10533 * 10534 * Can be called with cred_guard_mutex held when called from 10535 * install_exec_creds(). 10536 */ 10537 void perf_event_exit_task(struct task_struct *child) 10538 { 10539 struct perf_event *event, *tmp; 10540 int ctxn; 10541 10542 mutex_lock(&child->perf_event_mutex); 10543 list_for_each_entry_safe(event, tmp, &child->perf_event_list, 10544 owner_entry) { 10545 list_del_init(&event->owner_entry); 10546 10547 /* 10548 * Ensure the list deletion is visible before we clear 10549 * the owner, closes a race against perf_release() where 10550 * we need to serialize on the owner->perf_event_mutex. 10551 */ 10552 smp_store_release(&event->owner, NULL); 10553 } 10554 mutex_unlock(&child->perf_event_mutex); 10555 10556 for_each_task_context_nr(ctxn) 10557 perf_event_exit_task_context(child, ctxn); 10558 10559 /* 10560 * The perf_event_exit_task_context calls perf_event_task 10561 * with child's task_ctx, which generates EXIT events for 10562 * child contexts and sets child->perf_event_ctxp[] to NULL. 10563 * At this point we need to send EXIT events to cpu contexts. 10564 */ 10565 perf_event_task(child, NULL, 0); 10566 } 10567 10568 static void perf_free_event(struct perf_event *event, 10569 struct perf_event_context *ctx) 10570 { 10571 struct perf_event *parent = event->parent; 10572 10573 if (WARN_ON_ONCE(!parent)) 10574 return; 10575 10576 mutex_lock(&parent->child_mutex); 10577 list_del_init(&event->child_list); 10578 mutex_unlock(&parent->child_mutex); 10579 10580 put_event(parent); 10581 10582 raw_spin_lock_irq(&ctx->lock); 10583 perf_group_detach(event); 10584 list_del_event(event, ctx); 10585 raw_spin_unlock_irq(&ctx->lock); 10586 free_event(event); 10587 } 10588 10589 /* 10590 * Free an unexposed, unused context as created by inheritance by 10591 * perf_event_init_task below, used by fork() in case of fail. 10592 * 10593 * Not all locks are strictly required, but take them anyway to be nice and 10594 * help out with the lockdep assertions. 10595 */ 10596 void perf_event_free_task(struct task_struct *task) 10597 { 10598 struct perf_event_context *ctx; 10599 struct perf_event *event, *tmp; 10600 int ctxn; 10601 10602 for_each_task_context_nr(ctxn) { 10603 ctx = task->perf_event_ctxp[ctxn]; 10604 if (!ctx) 10605 continue; 10606 10607 mutex_lock(&ctx->mutex); 10608 raw_spin_lock_irq(&ctx->lock); 10609 /* 10610 * Destroy the task <-> ctx relation and mark the context dead. 10611 * 10612 * This is important because even though the task hasn't been 10613 * exposed yet the context has been (through child_list). 10614 */ 10615 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL); 10616 WRITE_ONCE(ctx->task, TASK_TOMBSTONE); 10617 put_task_struct(task); /* cannot be last */ 10618 raw_spin_unlock_irq(&ctx->lock); 10619 10620 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) 10621 perf_free_event(event, ctx); 10622 10623 mutex_unlock(&ctx->mutex); 10624 put_ctx(ctx); 10625 } 10626 } 10627 10628 void perf_event_delayed_put(struct task_struct *task) 10629 { 10630 int ctxn; 10631 10632 for_each_task_context_nr(ctxn) 10633 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]); 10634 } 10635 10636 struct file *perf_event_get(unsigned int fd) 10637 { 10638 struct file *file; 10639 10640 file = fget_raw(fd); 10641 if (!file) 10642 return ERR_PTR(-EBADF); 10643 10644 if (file->f_op != &perf_fops) { 10645 fput(file); 10646 return ERR_PTR(-EBADF); 10647 } 10648 10649 return file; 10650 } 10651 10652 const struct perf_event_attr *perf_event_attrs(struct perf_event *event) 10653 { 10654 if (!event) 10655 return ERR_PTR(-EINVAL); 10656 10657 return &event->attr; 10658 } 10659 10660 /* 10661 * Inherit a event from parent task to child task. 10662 * 10663 * Returns: 10664 * - valid pointer on success 10665 * - NULL for orphaned events 10666 * - IS_ERR() on error 10667 */ 10668 static struct perf_event * 10669 inherit_event(struct perf_event *parent_event, 10670 struct task_struct *parent, 10671 struct perf_event_context *parent_ctx, 10672 struct task_struct *child, 10673 struct perf_event *group_leader, 10674 struct perf_event_context *child_ctx) 10675 { 10676 enum perf_event_active_state parent_state = parent_event->state; 10677 struct perf_event *child_event; 10678 unsigned long flags; 10679 10680 /* 10681 * Instead of creating recursive hierarchies of events, 10682 * we link inherited events back to the original parent, 10683 * which has a filp for sure, which we use as the reference 10684 * count: 10685 */ 10686 if (parent_event->parent) 10687 parent_event = parent_event->parent; 10688 10689 child_event = perf_event_alloc(&parent_event->attr, 10690 parent_event->cpu, 10691 child, 10692 group_leader, parent_event, 10693 NULL, NULL, -1); 10694 if (IS_ERR(child_event)) 10695 return child_event; 10696 10697 /* 10698 * is_orphaned_event() and list_add_tail(&parent_event->child_list) 10699 * must be under the same lock in order to serialize against 10700 * perf_event_release_kernel(), such that either we must observe 10701 * is_orphaned_event() or they will observe us on the child_list. 10702 */ 10703 mutex_lock(&parent_event->child_mutex); 10704 if (is_orphaned_event(parent_event) || 10705 !atomic_long_inc_not_zero(&parent_event->refcount)) { 10706 mutex_unlock(&parent_event->child_mutex); 10707 free_event(child_event); 10708 return NULL; 10709 } 10710 10711 get_ctx(child_ctx); 10712 10713 /* 10714 * Make the child state follow the state of the parent event, 10715 * not its attr.disabled bit. We hold the parent's mutex, 10716 * so we won't race with perf_event_{en, dis}able_family. 10717 */ 10718 if (parent_state >= PERF_EVENT_STATE_INACTIVE) 10719 child_event->state = PERF_EVENT_STATE_INACTIVE; 10720 else 10721 child_event->state = PERF_EVENT_STATE_OFF; 10722 10723 if (parent_event->attr.freq) { 10724 u64 sample_period = parent_event->hw.sample_period; 10725 struct hw_perf_event *hwc = &child_event->hw; 10726 10727 hwc->sample_period = sample_period; 10728 hwc->last_period = sample_period; 10729 10730 local64_set(&hwc->period_left, sample_period); 10731 } 10732 10733 child_event->ctx = child_ctx; 10734 child_event->overflow_handler = parent_event->overflow_handler; 10735 child_event->overflow_handler_context 10736 = parent_event->overflow_handler_context; 10737 10738 /* 10739 * Precalculate sample_data sizes 10740 */ 10741 perf_event__header_size(child_event); 10742 perf_event__id_header_size(child_event); 10743 10744 /* 10745 * Link it up in the child's context: 10746 */ 10747 raw_spin_lock_irqsave(&child_ctx->lock, flags); 10748 add_event_to_ctx(child_event, child_ctx); 10749 raw_spin_unlock_irqrestore(&child_ctx->lock, flags); 10750 10751 /* 10752 * Link this into the parent event's child list 10753 */ 10754 list_add_tail(&child_event->child_list, &parent_event->child_list); 10755 mutex_unlock(&parent_event->child_mutex); 10756 10757 return child_event; 10758 } 10759 10760 /* 10761 * Inherits an event group. 10762 * 10763 * This will quietly suppress orphaned events; !inherit_event() is not an error. 10764 * This matches with perf_event_release_kernel() removing all child events. 10765 * 10766 * Returns: 10767 * - 0 on success 10768 * - <0 on error 10769 */ 10770 static int inherit_group(struct perf_event *parent_event, 10771 struct task_struct *parent, 10772 struct perf_event_context *parent_ctx, 10773 struct task_struct *child, 10774 struct perf_event_context *child_ctx) 10775 { 10776 struct perf_event *leader; 10777 struct perf_event *sub; 10778 struct perf_event *child_ctr; 10779 10780 leader = inherit_event(parent_event, parent, parent_ctx, 10781 child, NULL, child_ctx); 10782 if (IS_ERR(leader)) 10783 return PTR_ERR(leader); 10784 /* 10785 * @leader can be NULL here because of is_orphaned_event(). In this 10786 * case inherit_event() will create individual events, similar to what 10787 * perf_group_detach() would do anyway. 10788 */ 10789 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) { 10790 child_ctr = inherit_event(sub, parent, parent_ctx, 10791 child, leader, child_ctx); 10792 if (IS_ERR(child_ctr)) 10793 return PTR_ERR(child_ctr); 10794 } 10795 return 0; 10796 } 10797 10798 /* 10799 * Creates the child task context and tries to inherit the event-group. 10800 * 10801 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave 10802 * inherited_all set when we 'fail' to inherit an orphaned event; this is 10803 * consistent with perf_event_release_kernel() removing all child events. 10804 * 10805 * Returns: 10806 * - 0 on success 10807 * - <0 on error 10808 */ 10809 static int 10810 inherit_task_group(struct perf_event *event, struct task_struct *parent, 10811 struct perf_event_context *parent_ctx, 10812 struct task_struct *child, int ctxn, 10813 int *inherited_all) 10814 { 10815 int ret; 10816 struct perf_event_context *child_ctx; 10817 10818 if (!event->attr.inherit) { 10819 *inherited_all = 0; 10820 return 0; 10821 } 10822 10823 child_ctx = child->perf_event_ctxp[ctxn]; 10824 if (!child_ctx) { 10825 /* 10826 * This is executed from the parent task context, so 10827 * inherit events that have been marked for cloning. 10828 * First allocate and initialize a context for the 10829 * child. 10830 */ 10831 child_ctx = alloc_perf_context(parent_ctx->pmu, child); 10832 if (!child_ctx) 10833 return -ENOMEM; 10834 10835 child->perf_event_ctxp[ctxn] = child_ctx; 10836 } 10837 10838 ret = inherit_group(event, parent, parent_ctx, 10839 child, child_ctx); 10840 10841 if (ret) 10842 *inherited_all = 0; 10843 10844 return ret; 10845 } 10846 10847 /* 10848 * Initialize the perf_event context in task_struct 10849 */ 10850 static int perf_event_init_context(struct task_struct *child, int ctxn) 10851 { 10852 struct perf_event_context *child_ctx, *parent_ctx; 10853 struct perf_event_context *cloned_ctx; 10854 struct perf_event *event; 10855 struct task_struct *parent = current; 10856 int inherited_all = 1; 10857 unsigned long flags; 10858 int ret = 0; 10859 10860 if (likely(!parent->perf_event_ctxp[ctxn])) 10861 return 0; 10862 10863 /* 10864 * If the parent's context is a clone, pin it so it won't get 10865 * swapped under us. 10866 */ 10867 parent_ctx = perf_pin_task_context(parent, ctxn); 10868 if (!parent_ctx) 10869 return 0; 10870 10871 /* 10872 * No need to check if parent_ctx != NULL here; since we saw 10873 * it non-NULL earlier, the only reason for it to become NULL 10874 * is if we exit, and since we're currently in the middle of 10875 * a fork we can't be exiting at the same time. 10876 */ 10877 10878 /* 10879 * Lock the parent list. No need to lock the child - not PID 10880 * hashed yet and not running, so nobody can access it. 10881 */ 10882 mutex_lock(&parent_ctx->mutex); 10883 10884 /* 10885 * We dont have to disable NMIs - we are only looking at 10886 * the list, not manipulating it: 10887 */ 10888 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) { 10889 ret = inherit_task_group(event, parent, parent_ctx, 10890 child, ctxn, &inherited_all); 10891 if (ret) 10892 goto out_unlock; 10893 } 10894 10895 /* 10896 * We can't hold ctx->lock when iterating the ->flexible_group list due 10897 * to allocations, but we need to prevent rotation because 10898 * rotate_ctx() will change the list from interrupt context. 10899 */ 10900 raw_spin_lock_irqsave(&parent_ctx->lock, flags); 10901 parent_ctx->rotate_disable = 1; 10902 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); 10903 10904 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) { 10905 ret = inherit_task_group(event, parent, parent_ctx, 10906 child, ctxn, &inherited_all); 10907 if (ret) 10908 goto out_unlock; 10909 } 10910 10911 raw_spin_lock_irqsave(&parent_ctx->lock, flags); 10912 parent_ctx->rotate_disable = 0; 10913 10914 child_ctx = child->perf_event_ctxp[ctxn]; 10915 10916 if (child_ctx && inherited_all) { 10917 /* 10918 * Mark the child context as a clone of the parent 10919 * context, or of whatever the parent is a clone of. 10920 * 10921 * Note that if the parent is a clone, the holding of 10922 * parent_ctx->lock avoids it from being uncloned. 10923 */ 10924 cloned_ctx = parent_ctx->parent_ctx; 10925 if (cloned_ctx) { 10926 child_ctx->parent_ctx = cloned_ctx; 10927 child_ctx->parent_gen = parent_ctx->parent_gen; 10928 } else { 10929 child_ctx->parent_ctx = parent_ctx; 10930 child_ctx->parent_gen = parent_ctx->generation; 10931 } 10932 get_ctx(child_ctx->parent_ctx); 10933 } 10934 10935 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); 10936 out_unlock: 10937 mutex_unlock(&parent_ctx->mutex); 10938 10939 perf_unpin_context(parent_ctx); 10940 put_ctx(parent_ctx); 10941 10942 return ret; 10943 } 10944 10945 /* 10946 * Initialize the perf_event context in task_struct 10947 */ 10948 int perf_event_init_task(struct task_struct *child) 10949 { 10950 int ctxn, ret; 10951 10952 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp)); 10953 mutex_init(&child->perf_event_mutex); 10954 INIT_LIST_HEAD(&child->perf_event_list); 10955 10956 for_each_task_context_nr(ctxn) { 10957 ret = perf_event_init_context(child, ctxn); 10958 if (ret) { 10959 perf_event_free_task(child); 10960 return ret; 10961 } 10962 } 10963 10964 return 0; 10965 } 10966 10967 static void __init perf_event_init_all_cpus(void) 10968 { 10969 struct swevent_htable *swhash; 10970 int cpu; 10971 10972 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL); 10973 10974 for_each_possible_cpu(cpu) { 10975 swhash = &per_cpu(swevent_htable, cpu); 10976 mutex_init(&swhash->hlist_mutex); 10977 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu)); 10978 10979 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu)); 10980 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu)); 10981 10982 #ifdef CONFIG_CGROUP_PERF 10983 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu)); 10984 #endif 10985 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu)); 10986 } 10987 } 10988 10989 void perf_swevent_init_cpu(unsigned int cpu) 10990 { 10991 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 10992 10993 mutex_lock(&swhash->hlist_mutex); 10994 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) { 10995 struct swevent_hlist *hlist; 10996 10997 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu)); 10998 WARN_ON(!hlist); 10999 rcu_assign_pointer(swhash->swevent_hlist, hlist); 11000 } 11001 mutex_unlock(&swhash->hlist_mutex); 11002 } 11003 11004 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE 11005 static void __perf_event_exit_context(void *__info) 11006 { 11007 struct perf_event_context *ctx = __info; 11008 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 11009 struct perf_event *event; 11010 11011 raw_spin_lock(&ctx->lock); 11012 list_for_each_entry(event, &ctx->event_list, event_entry) 11013 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP); 11014 raw_spin_unlock(&ctx->lock); 11015 } 11016 11017 static void perf_event_exit_cpu_context(int cpu) 11018 { 11019 struct perf_cpu_context *cpuctx; 11020 struct perf_event_context *ctx; 11021 struct pmu *pmu; 11022 11023 mutex_lock(&pmus_lock); 11024 list_for_each_entry(pmu, &pmus, entry) { 11025 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 11026 ctx = &cpuctx->ctx; 11027 11028 mutex_lock(&ctx->mutex); 11029 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1); 11030 cpuctx->online = 0; 11031 mutex_unlock(&ctx->mutex); 11032 } 11033 cpumask_clear_cpu(cpu, perf_online_mask); 11034 mutex_unlock(&pmus_lock); 11035 } 11036 #else 11037 11038 static void perf_event_exit_cpu_context(int cpu) { } 11039 11040 #endif 11041 11042 int perf_event_init_cpu(unsigned int cpu) 11043 { 11044 struct perf_cpu_context *cpuctx; 11045 struct perf_event_context *ctx; 11046 struct pmu *pmu; 11047 11048 perf_swevent_init_cpu(cpu); 11049 11050 mutex_lock(&pmus_lock); 11051 cpumask_set_cpu(cpu, perf_online_mask); 11052 list_for_each_entry(pmu, &pmus, entry) { 11053 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 11054 ctx = &cpuctx->ctx; 11055 11056 mutex_lock(&ctx->mutex); 11057 cpuctx->online = 1; 11058 mutex_unlock(&ctx->mutex); 11059 } 11060 mutex_unlock(&pmus_lock); 11061 11062 return 0; 11063 } 11064 11065 int perf_event_exit_cpu(unsigned int cpu) 11066 { 11067 perf_event_exit_cpu_context(cpu); 11068 return 0; 11069 } 11070 11071 static int 11072 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v) 11073 { 11074 int cpu; 11075 11076 for_each_online_cpu(cpu) 11077 perf_event_exit_cpu(cpu); 11078 11079 return NOTIFY_OK; 11080 } 11081 11082 /* 11083 * Run the perf reboot notifier at the very last possible moment so that 11084 * the generic watchdog code runs as long as possible. 11085 */ 11086 static struct notifier_block perf_reboot_notifier = { 11087 .notifier_call = perf_reboot, 11088 .priority = INT_MIN, 11089 }; 11090 11091 void __init perf_event_init(void) 11092 { 11093 int ret; 11094 11095 idr_init(&pmu_idr); 11096 11097 perf_event_init_all_cpus(); 11098 init_srcu_struct(&pmus_srcu); 11099 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE); 11100 perf_pmu_register(&perf_cpu_clock, NULL, -1); 11101 perf_pmu_register(&perf_task_clock, NULL, -1); 11102 perf_tp_register(); 11103 perf_event_init_cpu(smp_processor_id()); 11104 register_reboot_notifier(&perf_reboot_notifier); 11105 11106 ret = init_hw_breakpoint(); 11107 WARN(ret, "hw_breakpoint initialization failed with: %d", ret); 11108 11109 /* 11110 * Build time assertion that we keep the data_head at the intended 11111 * location. IOW, validation we got the __reserved[] size right. 11112 */ 11113 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head)) 11114 != 1024); 11115 } 11116 11117 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr, 11118 char *page) 11119 { 11120 struct perf_pmu_events_attr *pmu_attr = 11121 container_of(attr, struct perf_pmu_events_attr, attr); 11122 11123 if (pmu_attr->event_str) 11124 return sprintf(page, "%s\n", pmu_attr->event_str); 11125 11126 return 0; 11127 } 11128 EXPORT_SYMBOL_GPL(perf_event_sysfs_show); 11129 11130 static int __init perf_event_sysfs_init(void) 11131 { 11132 struct pmu *pmu; 11133 int ret; 11134 11135 mutex_lock(&pmus_lock); 11136 11137 ret = bus_register(&pmu_bus); 11138 if (ret) 11139 goto unlock; 11140 11141 list_for_each_entry(pmu, &pmus, entry) { 11142 if (!pmu->name || pmu->type < 0) 11143 continue; 11144 11145 ret = pmu_dev_alloc(pmu); 11146 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret); 11147 } 11148 pmu_bus_running = 1; 11149 ret = 0; 11150 11151 unlock: 11152 mutex_unlock(&pmus_lock); 11153 11154 return ret; 11155 } 11156 device_initcall(perf_event_sysfs_init); 11157 11158 #ifdef CONFIG_CGROUP_PERF 11159 static struct cgroup_subsys_state * 11160 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) 11161 { 11162 struct perf_cgroup *jc; 11163 11164 jc = kzalloc(sizeof(*jc), GFP_KERNEL); 11165 if (!jc) 11166 return ERR_PTR(-ENOMEM); 11167 11168 jc->info = alloc_percpu(struct perf_cgroup_info); 11169 if (!jc->info) { 11170 kfree(jc); 11171 return ERR_PTR(-ENOMEM); 11172 } 11173 11174 return &jc->css; 11175 } 11176 11177 static void perf_cgroup_css_free(struct cgroup_subsys_state *css) 11178 { 11179 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css); 11180 11181 free_percpu(jc->info); 11182 kfree(jc); 11183 } 11184 11185 static int __perf_cgroup_move(void *info) 11186 { 11187 struct task_struct *task = info; 11188 rcu_read_lock(); 11189 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN); 11190 rcu_read_unlock(); 11191 return 0; 11192 } 11193 11194 static void perf_cgroup_attach(struct cgroup_taskset *tset) 11195 { 11196 struct task_struct *task; 11197 struct cgroup_subsys_state *css; 11198 11199 cgroup_taskset_for_each(task, css, tset) 11200 task_function_call(task, __perf_cgroup_move, task); 11201 } 11202 11203 struct cgroup_subsys perf_event_cgrp_subsys = { 11204 .css_alloc = perf_cgroup_css_alloc, 11205 .css_free = perf_cgroup_css_free, 11206 .attach = perf_cgroup_attach, 11207 /* 11208 * Implicitly enable on dfl hierarchy so that perf events can 11209 * always be filtered by cgroup2 path as long as perf_event 11210 * controller is not mounted on a legacy hierarchy. 11211 */ 11212 .implicit_on_dfl = true, 11213 }; 11214 #endif /* CONFIG_CGROUP_PERF */ 11215