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