1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Performance events core code: 4 * 5 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de> 6 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar 7 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra 8 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com> 9 */ 10 11 #include <linux/fs.h> 12 #include <linux/mm.h> 13 #include <linux/cpu.h> 14 #include <linux/smp.h> 15 #include <linux/idr.h> 16 #include <linux/file.h> 17 #include <linux/poll.h> 18 #include <linux/slab.h> 19 #include <linux/hash.h> 20 #include <linux/tick.h> 21 #include <linux/sysfs.h> 22 #include <linux/dcache.h> 23 #include <linux/percpu.h> 24 #include <linux/ptrace.h> 25 #include <linux/reboot.h> 26 #include <linux/vmstat.h> 27 #include <linux/device.h> 28 #include <linux/export.h> 29 #include <linux/vmalloc.h> 30 #include <linux/hardirq.h> 31 #include <linux/rculist.h> 32 #include <linux/uaccess.h> 33 #include <linux/syscalls.h> 34 #include <linux/anon_inodes.h> 35 #include <linux/kernel_stat.h> 36 #include <linux/cgroup.h> 37 #include <linux/perf_event.h> 38 #include <linux/trace_events.h> 39 #include <linux/hw_breakpoint.h> 40 #include <linux/mm_types.h> 41 #include <linux/module.h> 42 #include <linux/mman.h> 43 #include <linux/compat.h> 44 #include <linux/bpf.h> 45 #include <linux/filter.h> 46 #include <linux/namei.h> 47 #include <linux/parser.h> 48 #include <linux/sched/clock.h> 49 #include <linux/sched/mm.h> 50 #include <linux/proc_ns.h> 51 #include <linux/mount.h> 52 53 #include "internal.h" 54 55 #include <asm/irq_regs.h> 56 57 typedef int (*remote_function_f)(void *); 58 59 struct remote_function_call { 60 struct task_struct *p; 61 remote_function_f func; 62 void *info; 63 int ret; 64 }; 65 66 static void remote_function(void *data) 67 { 68 struct remote_function_call *tfc = data; 69 struct task_struct *p = tfc->p; 70 71 if (p) { 72 /* -EAGAIN */ 73 if (task_cpu(p) != smp_processor_id()) 74 return; 75 76 /* 77 * Now that we're on right CPU with IRQs disabled, we can test 78 * if we hit the right task without races. 79 */ 80 81 tfc->ret = -ESRCH; /* No such (running) process */ 82 if (p != current) 83 return; 84 } 85 86 tfc->ret = tfc->func(tfc->info); 87 } 88 89 /** 90 * task_function_call - call a function on the cpu on which a task runs 91 * @p: the task to evaluate 92 * @func: the function to be called 93 * @info: the function call argument 94 * 95 * Calls the function @func when the task is currently running. This might 96 * be on the current CPU, which just calls the function directly 97 * 98 * returns: @func return value, or 99 * -ESRCH - when the process isn't running 100 * -EAGAIN - when the process moved away 101 */ 102 static int 103 task_function_call(struct task_struct *p, remote_function_f func, void *info) 104 { 105 struct remote_function_call data = { 106 .p = p, 107 .func = func, 108 .info = info, 109 .ret = -EAGAIN, 110 }; 111 int ret; 112 113 do { 114 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1); 115 if (!ret) 116 ret = data.ret; 117 } while (ret == -EAGAIN); 118 119 return ret; 120 } 121 122 /** 123 * cpu_function_call - call a function on the cpu 124 * @func: the function to be called 125 * @info: the function call argument 126 * 127 * Calls the function @func on the remote cpu. 128 * 129 * returns: @func return value or -ENXIO when the cpu is offline 130 */ 131 static int cpu_function_call(int cpu, remote_function_f func, void *info) 132 { 133 struct remote_function_call data = { 134 .p = NULL, 135 .func = func, 136 .info = info, 137 .ret = -ENXIO, /* No such CPU */ 138 }; 139 140 smp_call_function_single(cpu, remote_function, &data, 1); 141 142 return data.ret; 143 } 144 145 static inline struct perf_cpu_context * 146 __get_cpu_context(struct perf_event_context *ctx) 147 { 148 return this_cpu_ptr(ctx->pmu->pmu_cpu_context); 149 } 150 151 static void perf_ctx_lock(struct perf_cpu_context *cpuctx, 152 struct perf_event_context *ctx) 153 { 154 raw_spin_lock(&cpuctx->ctx.lock); 155 if (ctx) 156 raw_spin_lock(&ctx->lock); 157 } 158 159 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx, 160 struct perf_event_context *ctx) 161 { 162 if (ctx) 163 raw_spin_unlock(&ctx->lock); 164 raw_spin_unlock(&cpuctx->ctx.lock); 165 } 166 167 #define TASK_TOMBSTONE ((void *)-1L) 168 169 static bool is_kernel_event(struct perf_event *event) 170 { 171 return READ_ONCE(event->owner) == TASK_TOMBSTONE; 172 } 173 174 /* 175 * On task ctx scheduling... 176 * 177 * When !ctx->nr_events a task context will not be scheduled. This means 178 * we can disable the scheduler hooks (for performance) without leaving 179 * pending task ctx state. 180 * 181 * This however results in two special cases: 182 * 183 * - removing the last event from a task ctx; this is relatively straight 184 * forward and is done in __perf_remove_from_context. 185 * 186 * - adding the first event to a task ctx; this is tricky because we cannot 187 * rely on ctx->is_active and therefore cannot use event_function_call(). 188 * See perf_install_in_context(). 189 * 190 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set. 191 */ 192 193 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *, 194 struct perf_event_context *, void *); 195 196 struct event_function_struct { 197 struct perf_event *event; 198 event_f func; 199 void *data; 200 }; 201 202 static int event_function(void *info) 203 { 204 struct event_function_struct *efs = info; 205 struct perf_event *event = efs->event; 206 struct perf_event_context *ctx = event->ctx; 207 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 208 struct perf_event_context *task_ctx = cpuctx->task_ctx; 209 int ret = 0; 210 211 lockdep_assert_irqs_disabled(); 212 213 perf_ctx_lock(cpuctx, task_ctx); 214 /* 215 * Since we do the IPI call without holding ctx->lock things can have 216 * changed, double check we hit the task we set out to hit. 217 */ 218 if (ctx->task) { 219 if (ctx->task != current) { 220 ret = -ESRCH; 221 goto unlock; 222 } 223 224 /* 225 * We only use event_function_call() on established contexts, 226 * and event_function() is only ever called when active (or 227 * rather, we'll have bailed in task_function_call() or the 228 * above ctx->task != current test), therefore we must have 229 * ctx->is_active here. 230 */ 231 WARN_ON_ONCE(!ctx->is_active); 232 /* 233 * And since we have ctx->is_active, cpuctx->task_ctx must 234 * match. 235 */ 236 WARN_ON_ONCE(task_ctx != ctx); 237 } else { 238 WARN_ON_ONCE(&cpuctx->ctx != ctx); 239 } 240 241 efs->func(event, cpuctx, ctx, efs->data); 242 unlock: 243 perf_ctx_unlock(cpuctx, task_ctx); 244 245 return ret; 246 } 247 248 static void event_function_call(struct perf_event *event, event_f func, void *data) 249 { 250 struct perf_event_context *ctx = event->ctx; 251 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */ 252 struct event_function_struct efs = { 253 .event = event, 254 .func = func, 255 .data = data, 256 }; 257 258 if (!event->parent) { 259 /* 260 * If this is a !child event, we must hold ctx::mutex to 261 * stabilize the the event->ctx relation. See 262 * perf_event_ctx_lock(). 263 */ 264 lockdep_assert_held(&ctx->mutex); 265 } 266 267 if (!task) { 268 cpu_function_call(event->cpu, event_function, &efs); 269 return; 270 } 271 272 if (task == TASK_TOMBSTONE) 273 return; 274 275 again: 276 if (!task_function_call(task, event_function, &efs)) 277 return; 278 279 raw_spin_lock_irq(&ctx->lock); 280 /* 281 * Reload the task pointer, it might have been changed by 282 * a concurrent perf_event_context_sched_out(). 283 */ 284 task = ctx->task; 285 if (task == TASK_TOMBSTONE) { 286 raw_spin_unlock_irq(&ctx->lock); 287 return; 288 } 289 if (ctx->is_active) { 290 raw_spin_unlock_irq(&ctx->lock); 291 goto again; 292 } 293 func(event, NULL, ctx, data); 294 raw_spin_unlock_irq(&ctx->lock); 295 } 296 297 /* 298 * Similar to event_function_call() + event_function(), but hard assumes IRQs 299 * are already disabled and we're on the right CPU. 300 */ 301 static void event_function_local(struct perf_event *event, event_f func, void *data) 302 { 303 struct perf_event_context *ctx = event->ctx; 304 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 305 struct task_struct *task = READ_ONCE(ctx->task); 306 struct perf_event_context *task_ctx = NULL; 307 308 lockdep_assert_irqs_disabled(); 309 310 if (task) { 311 if (task == TASK_TOMBSTONE) 312 return; 313 314 task_ctx = ctx; 315 } 316 317 perf_ctx_lock(cpuctx, task_ctx); 318 319 task = ctx->task; 320 if (task == TASK_TOMBSTONE) 321 goto unlock; 322 323 if (task) { 324 /* 325 * We must be either inactive or active and the right task, 326 * otherwise we're screwed, since we cannot IPI to somewhere 327 * else. 328 */ 329 if (ctx->is_active) { 330 if (WARN_ON_ONCE(task != current)) 331 goto unlock; 332 333 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx)) 334 goto unlock; 335 } 336 } else { 337 WARN_ON_ONCE(&cpuctx->ctx != ctx); 338 } 339 340 func(event, cpuctx, ctx, data); 341 unlock: 342 perf_ctx_unlock(cpuctx, task_ctx); 343 } 344 345 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\ 346 PERF_FLAG_FD_OUTPUT |\ 347 PERF_FLAG_PID_CGROUP |\ 348 PERF_FLAG_FD_CLOEXEC) 349 350 /* 351 * branch priv levels that need permission checks 352 */ 353 #define PERF_SAMPLE_BRANCH_PERM_PLM \ 354 (PERF_SAMPLE_BRANCH_KERNEL |\ 355 PERF_SAMPLE_BRANCH_HV) 356 357 enum event_type_t { 358 EVENT_FLEXIBLE = 0x1, 359 EVENT_PINNED = 0x2, 360 EVENT_TIME = 0x4, 361 /* see ctx_resched() for details */ 362 EVENT_CPU = 0x8, 363 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED, 364 }; 365 366 /* 367 * perf_sched_events : >0 events exist 368 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu 369 */ 370 371 static void perf_sched_delayed(struct work_struct *work); 372 DEFINE_STATIC_KEY_FALSE(perf_sched_events); 373 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed); 374 static DEFINE_MUTEX(perf_sched_mutex); 375 static atomic_t perf_sched_count; 376 377 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events); 378 static DEFINE_PER_CPU(int, perf_sched_cb_usages); 379 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events); 380 381 static atomic_t nr_mmap_events __read_mostly; 382 static atomic_t nr_comm_events __read_mostly; 383 static atomic_t nr_namespaces_events __read_mostly; 384 static atomic_t nr_task_events __read_mostly; 385 static atomic_t nr_freq_events __read_mostly; 386 static atomic_t nr_switch_events __read_mostly; 387 static atomic_t nr_ksymbol_events __read_mostly; 388 static atomic_t nr_bpf_events __read_mostly; 389 390 static LIST_HEAD(pmus); 391 static DEFINE_MUTEX(pmus_lock); 392 static struct srcu_struct pmus_srcu; 393 static cpumask_var_t perf_online_mask; 394 395 /* 396 * perf event paranoia level: 397 * -1 - not paranoid at all 398 * 0 - disallow raw tracepoint access for unpriv 399 * 1 - disallow cpu events for unpriv 400 * 2 - disallow kernel profiling for unpriv 401 */ 402 int sysctl_perf_event_paranoid __read_mostly = 2; 403 404 /* Minimum for 512 kiB + 1 user control page */ 405 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */ 406 407 /* 408 * max perf event sample rate 409 */ 410 #define DEFAULT_MAX_SAMPLE_RATE 100000 411 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE) 412 #define DEFAULT_CPU_TIME_MAX_PERCENT 25 413 414 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE; 415 416 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ); 417 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS; 418 419 static int perf_sample_allowed_ns __read_mostly = 420 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100; 421 422 static void update_perf_cpu_limits(void) 423 { 424 u64 tmp = perf_sample_period_ns; 425 426 tmp *= sysctl_perf_cpu_time_max_percent; 427 tmp = div_u64(tmp, 100); 428 if (!tmp) 429 tmp = 1; 430 431 WRITE_ONCE(perf_sample_allowed_ns, tmp); 432 } 433 434 static bool perf_rotate_context(struct perf_cpu_context *cpuctx); 435 436 int perf_proc_update_handler(struct ctl_table *table, int write, 437 void __user *buffer, size_t *lenp, 438 loff_t *ppos) 439 { 440 int ret; 441 int perf_cpu = sysctl_perf_cpu_time_max_percent; 442 /* 443 * If throttling is disabled don't allow the write: 444 */ 445 if (write && (perf_cpu == 100 || perf_cpu == 0)) 446 return -EINVAL; 447 448 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); 449 if (ret || !write) 450 return ret; 451 452 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ); 453 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; 454 update_perf_cpu_limits(); 455 456 return 0; 457 } 458 459 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT; 460 461 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write, 462 void __user *buffer, size_t *lenp, 463 loff_t *ppos) 464 { 465 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); 466 467 if (ret || !write) 468 return ret; 469 470 if (sysctl_perf_cpu_time_max_percent == 100 || 471 sysctl_perf_cpu_time_max_percent == 0) { 472 printk(KERN_WARNING 473 "perf: Dynamic interrupt throttling disabled, can hang your system!\n"); 474 WRITE_ONCE(perf_sample_allowed_ns, 0); 475 } else { 476 update_perf_cpu_limits(); 477 } 478 479 return 0; 480 } 481 482 /* 483 * perf samples are done in some very critical code paths (NMIs). 484 * If they take too much CPU time, the system can lock up and not 485 * get any real work done. This will drop the sample rate when 486 * we detect that events are taking too long. 487 */ 488 #define NR_ACCUMULATED_SAMPLES 128 489 static DEFINE_PER_CPU(u64, running_sample_length); 490 491 static u64 __report_avg; 492 static u64 __report_allowed; 493 494 static void perf_duration_warn(struct irq_work *w) 495 { 496 printk_ratelimited(KERN_INFO 497 "perf: interrupt took too long (%lld > %lld), lowering " 498 "kernel.perf_event_max_sample_rate to %d\n", 499 __report_avg, __report_allowed, 500 sysctl_perf_event_sample_rate); 501 } 502 503 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn); 504 505 void perf_sample_event_took(u64 sample_len_ns) 506 { 507 u64 max_len = READ_ONCE(perf_sample_allowed_ns); 508 u64 running_len; 509 u64 avg_len; 510 u32 max; 511 512 if (max_len == 0) 513 return; 514 515 /* Decay the counter by 1 average sample. */ 516 running_len = __this_cpu_read(running_sample_length); 517 running_len -= running_len/NR_ACCUMULATED_SAMPLES; 518 running_len += sample_len_ns; 519 __this_cpu_write(running_sample_length, running_len); 520 521 /* 522 * Note: this will be biased artifically low until we have 523 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us 524 * from having to maintain a count. 525 */ 526 avg_len = running_len/NR_ACCUMULATED_SAMPLES; 527 if (avg_len <= max_len) 528 return; 529 530 __report_avg = avg_len; 531 __report_allowed = max_len; 532 533 /* 534 * Compute a throttle threshold 25% below the current duration. 535 */ 536 avg_len += avg_len / 4; 537 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent; 538 if (avg_len < max) 539 max /= (u32)avg_len; 540 else 541 max = 1; 542 543 WRITE_ONCE(perf_sample_allowed_ns, avg_len); 544 WRITE_ONCE(max_samples_per_tick, max); 545 546 sysctl_perf_event_sample_rate = max * HZ; 547 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; 548 549 if (!irq_work_queue(&perf_duration_work)) { 550 early_printk("perf: interrupt took too long (%lld > %lld), lowering " 551 "kernel.perf_event_max_sample_rate to %d\n", 552 __report_avg, __report_allowed, 553 sysctl_perf_event_sample_rate); 554 } 555 } 556 557 static atomic64_t perf_event_id; 558 559 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, 560 enum event_type_t event_type); 561 562 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, 563 enum event_type_t event_type, 564 struct task_struct *task); 565 566 static void update_context_time(struct perf_event_context *ctx); 567 static u64 perf_event_time(struct perf_event *event); 568 569 void __weak perf_event_print_debug(void) { } 570 571 extern __weak const char *perf_pmu_name(void) 572 { 573 return "pmu"; 574 } 575 576 static inline u64 perf_clock(void) 577 { 578 return local_clock(); 579 } 580 581 static inline u64 perf_event_clock(struct perf_event *event) 582 { 583 return event->clock(); 584 } 585 586 /* 587 * State based event timekeeping... 588 * 589 * The basic idea is to use event->state to determine which (if any) time 590 * fields to increment with the current delta. This means we only need to 591 * update timestamps when we change state or when they are explicitly requested 592 * (read). 593 * 594 * Event groups make things a little more complicated, but not terribly so. The 595 * rules for a group are that if the group leader is OFF the entire group is 596 * OFF, irrespecive of what the group member states are. This results in 597 * __perf_effective_state(). 598 * 599 * A futher ramification is that when a group leader flips between OFF and 600 * !OFF, we need to update all group member times. 601 * 602 * 603 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we 604 * need to make sure the relevant context time is updated before we try and 605 * update our timestamps. 606 */ 607 608 static __always_inline enum perf_event_state 609 __perf_effective_state(struct perf_event *event) 610 { 611 struct perf_event *leader = event->group_leader; 612 613 if (leader->state <= PERF_EVENT_STATE_OFF) 614 return leader->state; 615 616 return event->state; 617 } 618 619 static __always_inline void 620 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running) 621 { 622 enum perf_event_state state = __perf_effective_state(event); 623 u64 delta = now - event->tstamp; 624 625 *enabled = event->total_time_enabled; 626 if (state >= PERF_EVENT_STATE_INACTIVE) 627 *enabled += delta; 628 629 *running = event->total_time_running; 630 if (state >= PERF_EVENT_STATE_ACTIVE) 631 *running += delta; 632 } 633 634 static void perf_event_update_time(struct perf_event *event) 635 { 636 u64 now = perf_event_time(event); 637 638 __perf_update_times(event, now, &event->total_time_enabled, 639 &event->total_time_running); 640 event->tstamp = now; 641 } 642 643 static void perf_event_update_sibling_time(struct perf_event *leader) 644 { 645 struct perf_event *sibling; 646 647 for_each_sibling_event(sibling, leader) 648 perf_event_update_time(sibling); 649 } 650 651 static void 652 perf_event_set_state(struct perf_event *event, enum perf_event_state state) 653 { 654 if (event->state == state) 655 return; 656 657 perf_event_update_time(event); 658 /* 659 * If a group leader gets enabled/disabled all its siblings 660 * are affected too. 661 */ 662 if ((event->state < 0) ^ (state < 0)) 663 perf_event_update_sibling_time(event); 664 665 WRITE_ONCE(event->state, state); 666 } 667 668 #ifdef CONFIG_CGROUP_PERF 669 670 static inline bool 671 perf_cgroup_match(struct perf_event *event) 672 { 673 struct perf_event_context *ctx = event->ctx; 674 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 675 676 /* @event doesn't care about cgroup */ 677 if (!event->cgrp) 678 return true; 679 680 /* wants specific cgroup scope but @cpuctx isn't associated with any */ 681 if (!cpuctx->cgrp) 682 return false; 683 684 /* 685 * Cgroup scoping is recursive. An event enabled for a cgroup is 686 * also enabled for all its descendant cgroups. If @cpuctx's 687 * cgroup is a descendant of @event's (the test covers identity 688 * case), it's a match. 689 */ 690 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup, 691 event->cgrp->css.cgroup); 692 } 693 694 static inline void perf_detach_cgroup(struct perf_event *event) 695 { 696 css_put(&event->cgrp->css); 697 event->cgrp = NULL; 698 } 699 700 static inline int is_cgroup_event(struct perf_event *event) 701 { 702 return event->cgrp != NULL; 703 } 704 705 static inline u64 perf_cgroup_event_time(struct perf_event *event) 706 { 707 struct perf_cgroup_info *t; 708 709 t = per_cpu_ptr(event->cgrp->info, event->cpu); 710 return t->time; 711 } 712 713 static inline void __update_cgrp_time(struct perf_cgroup *cgrp) 714 { 715 struct perf_cgroup_info *info; 716 u64 now; 717 718 now = perf_clock(); 719 720 info = this_cpu_ptr(cgrp->info); 721 722 info->time += now - info->timestamp; 723 info->timestamp = now; 724 } 725 726 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) 727 { 728 struct perf_cgroup *cgrp = cpuctx->cgrp; 729 struct cgroup_subsys_state *css; 730 731 if (cgrp) { 732 for (css = &cgrp->css; css; css = css->parent) { 733 cgrp = container_of(css, struct perf_cgroup, css); 734 __update_cgrp_time(cgrp); 735 } 736 } 737 } 738 739 static inline void update_cgrp_time_from_event(struct perf_event *event) 740 { 741 struct perf_cgroup *cgrp; 742 743 /* 744 * ensure we access cgroup data only when needed and 745 * when we know the cgroup is pinned (css_get) 746 */ 747 if (!is_cgroup_event(event)) 748 return; 749 750 cgrp = perf_cgroup_from_task(current, event->ctx); 751 /* 752 * Do not update time when cgroup is not active 753 */ 754 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup)) 755 __update_cgrp_time(event->cgrp); 756 } 757 758 static inline void 759 perf_cgroup_set_timestamp(struct task_struct *task, 760 struct perf_event_context *ctx) 761 { 762 struct perf_cgroup *cgrp; 763 struct perf_cgroup_info *info; 764 struct cgroup_subsys_state *css; 765 766 /* 767 * ctx->lock held by caller 768 * ensure we do not access cgroup data 769 * unless we have the cgroup pinned (css_get) 770 */ 771 if (!task || !ctx->nr_cgroups) 772 return; 773 774 cgrp = perf_cgroup_from_task(task, ctx); 775 776 for (css = &cgrp->css; css; css = css->parent) { 777 cgrp = container_of(css, struct perf_cgroup, css); 778 info = this_cpu_ptr(cgrp->info); 779 info->timestamp = ctx->timestamp; 780 } 781 } 782 783 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list); 784 785 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */ 786 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */ 787 788 /* 789 * reschedule events based on the cgroup constraint of task. 790 * 791 * mode SWOUT : schedule out everything 792 * mode SWIN : schedule in based on cgroup for next 793 */ 794 static void perf_cgroup_switch(struct task_struct *task, int mode) 795 { 796 struct perf_cpu_context *cpuctx; 797 struct list_head *list; 798 unsigned long flags; 799 800 /* 801 * Disable interrupts and preemption to avoid this CPU's 802 * cgrp_cpuctx_entry to change under us. 803 */ 804 local_irq_save(flags); 805 806 list = this_cpu_ptr(&cgrp_cpuctx_list); 807 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) { 808 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0); 809 810 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 811 perf_pmu_disable(cpuctx->ctx.pmu); 812 813 if (mode & PERF_CGROUP_SWOUT) { 814 cpu_ctx_sched_out(cpuctx, EVENT_ALL); 815 /* 816 * must not be done before ctxswout due 817 * to event_filter_match() in event_sched_out() 818 */ 819 cpuctx->cgrp = NULL; 820 } 821 822 if (mode & PERF_CGROUP_SWIN) { 823 WARN_ON_ONCE(cpuctx->cgrp); 824 /* 825 * set cgrp before ctxsw in to allow 826 * event_filter_match() to not have to pass 827 * task around 828 * we pass the cpuctx->ctx to perf_cgroup_from_task() 829 * because cgorup events are only per-cpu 830 */ 831 cpuctx->cgrp = perf_cgroup_from_task(task, 832 &cpuctx->ctx); 833 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task); 834 } 835 perf_pmu_enable(cpuctx->ctx.pmu); 836 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 837 } 838 839 local_irq_restore(flags); 840 } 841 842 static inline void perf_cgroup_sched_out(struct task_struct *task, 843 struct task_struct *next) 844 { 845 struct perf_cgroup *cgrp1; 846 struct perf_cgroup *cgrp2 = NULL; 847 848 rcu_read_lock(); 849 /* 850 * we come here when we know perf_cgroup_events > 0 851 * we do not need to pass the ctx here because we know 852 * we are holding the rcu lock 853 */ 854 cgrp1 = perf_cgroup_from_task(task, NULL); 855 cgrp2 = perf_cgroup_from_task(next, NULL); 856 857 /* 858 * only schedule out current cgroup events if we know 859 * that we are switching to a different cgroup. Otherwise, 860 * do no touch the cgroup events. 861 */ 862 if (cgrp1 != cgrp2) 863 perf_cgroup_switch(task, PERF_CGROUP_SWOUT); 864 865 rcu_read_unlock(); 866 } 867 868 static inline void perf_cgroup_sched_in(struct task_struct *prev, 869 struct task_struct *task) 870 { 871 struct perf_cgroup *cgrp1; 872 struct perf_cgroup *cgrp2 = NULL; 873 874 rcu_read_lock(); 875 /* 876 * we come here when we know perf_cgroup_events > 0 877 * we do not need to pass the ctx here because we know 878 * we are holding the rcu lock 879 */ 880 cgrp1 = perf_cgroup_from_task(task, NULL); 881 cgrp2 = perf_cgroup_from_task(prev, NULL); 882 883 /* 884 * only need to schedule in cgroup events if we are changing 885 * cgroup during ctxsw. Cgroup events were not scheduled 886 * out of ctxsw out if that was not the case. 887 */ 888 if (cgrp1 != cgrp2) 889 perf_cgroup_switch(task, PERF_CGROUP_SWIN); 890 891 rcu_read_unlock(); 892 } 893 894 static inline int perf_cgroup_connect(int fd, struct perf_event *event, 895 struct perf_event_attr *attr, 896 struct perf_event *group_leader) 897 { 898 struct perf_cgroup *cgrp; 899 struct cgroup_subsys_state *css; 900 struct fd f = fdget(fd); 901 int ret = 0; 902 903 if (!f.file) 904 return -EBADF; 905 906 css = css_tryget_online_from_dir(f.file->f_path.dentry, 907 &perf_event_cgrp_subsys); 908 if (IS_ERR(css)) { 909 ret = PTR_ERR(css); 910 goto out; 911 } 912 913 cgrp = container_of(css, struct perf_cgroup, css); 914 event->cgrp = cgrp; 915 916 /* 917 * all events in a group must monitor 918 * the same cgroup because a task belongs 919 * to only one perf cgroup at a time 920 */ 921 if (group_leader && group_leader->cgrp != cgrp) { 922 perf_detach_cgroup(event); 923 ret = -EINVAL; 924 } 925 out: 926 fdput(f); 927 return ret; 928 } 929 930 static inline void 931 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) 932 { 933 struct perf_cgroup_info *t; 934 t = per_cpu_ptr(event->cgrp->info, event->cpu); 935 event->shadow_ctx_time = now - t->timestamp; 936 } 937 938 /* 939 * Update cpuctx->cgrp so that it is set when first cgroup event is added and 940 * cleared when last cgroup event is removed. 941 */ 942 static inline void 943 list_update_cgroup_event(struct perf_event *event, 944 struct perf_event_context *ctx, bool add) 945 { 946 struct perf_cpu_context *cpuctx; 947 struct list_head *cpuctx_entry; 948 949 if (!is_cgroup_event(event)) 950 return; 951 952 /* 953 * Because cgroup events are always per-cpu events, 954 * this will always be called from the right CPU. 955 */ 956 cpuctx = __get_cpu_context(ctx); 957 958 /* 959 * Since setting cpuctx->cgrp is conditional on the current @cgrp 960 * matching the event's cgroup, we must do this for every new event, 961 * because if the first would mismatch, the second would not try again 962 * and we would leave cpuctx->cgrp unset. 963 */ 964 if (add && !cpuctx->cgrp) { 965 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx); 966 967 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup)) 968 cpuctx->cgrp = cgrp; 969 } 970 971 if (add && ctx->nr_cgroups++) 972 return; 973 else if (!add && --ctx->nr_cgroups) 974 return; 975 976 /* no cgroup running */ 977 if (!add) 978 cpuctx->cgrp = NULL; 979 980 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry; 981 if (add) 982 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list)); 983 else 984 list_del(cpuctx_entry); 985 } 986 987 #else /* !CONFIG_CGROUP_PERF */ 988 989 static inline bool 990 perf_cgroup_match(struct perf_event *event) 991 { 992 return true; 993 } 994 995 static inline void perf_detach_cgroup(struct perf_event *event) 996 {} 997 998 static inline int is_cgroup_event(struct perf_event *event) 999 { 1000 return 0; 1001 } 1002 1003 static inline void update_cgrp_time_from_event(struct perf_event *event) 1004 { 1005 } 1006 1007 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx) 1008 { 1009 } 1010 1011 static inline void perf_cgroup_sched_out(struct task_struct *task, 1012 struct task_struct *next) 1013 { 1014 } 1015 1016 static inline void perf_cgroup_sched_in(struct task_struct *prev, 1017 struct task_struct *task) 1018 { 1019 } 1020 1021 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event, 1022 struct perf_event_attr *attr, 1023 struct perf_event *group_leader) 1024 { 1025 return -EINVAL; 1026 } 1027 1028 static inline void 1029 perf_cgroup_set_timestamp(struct task_struct *task, 1030 struct perf_event_context *ctx) 1031 { 1032 } 1033 1034 void 1035 perf_cgroup_switch(struct task_struct *task, struct task_struct *next) 1036 { 1037 } 1038 1039 static inline void 1040 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now) 1041 { 1042 } 1043 1044 static inline u64 perf_cgroup_event_time(struct perf_event *event) 1045 { 1046 return 0; 1047 } 1048 1049 static inline void 1050 list_update_cgroup_event(struct perf_event *event, 1051 struct perf_event_context *ctx, bool add) 1052 { 1053 } 1054 1055 #endif 1056 1057 /* 1058 * set default to be dependent on timer tick just 1059 * like original code 1060 */ 1061 #define PERF_CPU_HRTIMER (1000 / HZ) 1062 /* 1063 * function must be called with interrupts disabled 1064 */ 1065 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr) 1066 { 1067 struct perf_cpu_context *cpuctx; 1068 bool rotations; 1069 1070 lockdep_assert_irqs_disabled(); 1071 1072 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer); 1073 rotations = perf_rotate_context(cpuctx); 1074 1075 raw_spin_lock(&cpuctx->hrtimer_lock); 1076 if (rotations) 1077 hrtimer_forward_now(hr, cpuctx->hrtimer_interval); 1078 else 1079 cpuctx->hrtimer_active = 0; 1080 raw_spin_unlock(&cpuctx->hrtimer_lock); 1081 1082 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART; 1083 } 1084 1085 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu) 1086 { 1087 struct hrtimer *timer = &cpuctx->hrtimer; 1088 struct pmu *pmu = cpuctx->ctx.pmu; 1089 u64 interval; 1090 1091 /* no multiplexing needed for SW PMU */ 1092 if (pmu->task_ctx_nr == perf_sw_context) 1093 return; 1094 1095 /* 1096 * check default is sane, if not set then force to 1097 * default interval (1/tick) 1098 */ 1099 interval = pmu->hrtimer_interval_ms; 1100 if (interval < 1) 1101 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER; 1102 1103 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval); 1104 1105 raw_spin_lock_init(&cpuctx->hrtimer_lock); 1106 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD); 1107 timer->function = perf_mux_hrtimer_handler; 1108 } 1109 1110 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx) 1111 { 1112 struct hrtimer *timer = &cpuctx->hrtimer; 1113 struct pmu *pmu = cpuctx->ctx.pmu; 1114 unsigned long flags; 1115 1116 /* not for SW PMU */ 1117 if (pmu->task_ctx_nr == perf_sw_context) 1118 return 0; 1119 1120 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags); 1121 if (!cpuctx->hrtimer_active) { 1122 cpuctx->hrtimer_active = 1; 1123 hrtimer_forward_now(timer, cpuctx->hrtimer_interval); 1124 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD); 1125 } 1126 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags); 1127 1128 return 0; 1129 } 1130 1131 void perf_pmu_disable(struct pmu *pmu) 1132 { 1133 int *count = this_cpu_ptr(pmu->pmu_disable_count); 1134 if (!(*count)++) 1135 pmu->pmu_disable(pmu); 1136 } 1137 1138 void perf_pmu_enable(struct pmu *pmu) 1139 { 1140 int *count = this_cpu_ptr(pmu->pmu_disable_count); 1141 if (!--(*count)) 1142 pmu->pmu_enable(pmu); 1143 } 1144 1145 static DEFINE_PER_CPU(struct list_head, active_ctx_list); 1146 1147 /* 1148 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and 1149 * perf_event_task_tick() are fully serialized because they're strictly cpu 1150 * affine and perf_event_ctx{activate,deactivate} are called with IRQs 1151 * disabled, while perf_event_task_tick is called from IRQ context. 1152 */ 1153 static void perf_event_ctx_activate(struct perf_event_context *ctx) 1154 { 1155 struct list_head *head = this_cpu_ptr(&active_ctx_list); 1156 1157 lockdep_assert_irqs_disabled(); 1158 1159 WARN_ON(!list_empty(&ctx->active_ctx_list)); 1160 1161 list_add(&ctx->active_ctx_list, head); 1162 } 1163 1164 static void perf_event_ctx_deactivate(struct perf_event_context *ctx) 1165 { 1166 lockdep_assert_irqs_disabled(); 1167 1168 WARN_ON(list_empty(&ctx->active_ctx_list)); 1169 1170 list_del_init(&ctx->active_ctx_list); 1171 } 1172 1173 static void get_ctx(struct perf_event_context *ctx) 1174 { 1175 refcount_inc(&ctx->refcount); 1176 } 1177 1178 static void free_ctx(struct rcu_head *head) 1179 { 1180 struct perf_event_context *ctx; 1181 1182 ctx = container_of(head, struct perf_event_context, rcu_head); 1183 kfree(ctx->task_ctx_data); 1184 kfree(ctx); 1185 } 1186 1187 static void put_ctx(struct perf_event_context *ctx) 1188 { 1189 if (refcount_dec_and_test(&ctx->refcount)) { 1190 if (ctx->parent_ctx) 1191 put_ctx(ctx->parent_ctx); 1192 if (ctx->task && ctx->task != TASK_TOMBSTONE) 1193 put_task_struct(ctx->task); 1194 call_rcu(&ctx->rcu_head, free_ctx); 1195 } 1196 } 1197 1198 /* 1199 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and 1200 * perf_pmu_migrate_context() we need some magic. 1201 * 1202 * Those places that change perf_event::ctx will hold both 1203 * perf_event_ctx::mutex of the 'old' and 'new' ctx value. 1204 * 1205 * Lock ordering is by mutex address. There are two other sites where 1206 * perf_event_context::mutex nests and those are: 1207 * 1208 * - perf_event_exit_task_context() [ child , 0 ] 1209 * perf_event_exit_event() 1210 * put_event() [ parent, 1 ] 1211 * 1212 * - perf_event_init_context() [ parent, 0 ] 1213 * inherit_task_group() 1214 * inherit_group() 1215 * inherit_event() 1216 * perf_event_alloc() 1217 * perf_init_event() 1218 * perf_try_init_event() [ child , 1 ] 1219 * 1220 * While it appears there is an obvious deadlock here -- the parent and child 1221 * nesting levels are inverted between the two. This is in fact safe because 1222 * life-time rules separate them. That is an exiting task cannot fork, and a 1223 * spawning task cannot (yet) exit. 1224 * 1225 * But remember that that these are parent<->child context relations, and 1226 * migration does not affect children, therefore these two orderings should not 1227 * interact. 1228 * 1229 * The change in perf_event::ctx does not affect children (as claimed above) 1230 * because the sys_perf_event_open() case will install a new event and break 1231 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only 1232 * concerned with cpuctx and that doesn't have children. 1233 * 1234 * The places that change perf_event::ctx will issue: 1235 * 1236 * perf_remove_from_context(); 1237 * synchronize_rcu(); 1238 * perf_install_in_context(); 1239 * 1240 * to affect the change. The remove_from_context() + synchronize_rcu() should 1241 * quiesce the event, after which we can install it in the new location. This 1242 * means that only external vectors (perf_fops, prctl) can perturb the event 1243 * while in transit. Therefore all such accessors should also acquire 1244 * perf_event_context::mutex to serialize against this. 1245 * 1246 * However; because event->ctx can change while we're waiting to acquire 1247 * ctx->mutex we must be careful and use the below perf_event_ctx_lock() 1248 * function. 1249 * 1250 * Lock order: 1251 * cred_guard_mutex 1252 * task_struct::perf_event_mutex 1253 * perf_event_context::mutex 1254 * perf_event::child_mutex; 1255 * perf_event_context::lock 1256 * perf_event::mmap_mutex 1257 * mmap_sem 1258 * perf_addr_filters_head::lock 1259 * 1260 * cpu_hotplug_lock 1261 * pmus_lock 1262 * cpuctx->mutex / perf_event_context::mutex 1263 */ 1264 static struct perf_event_context * 1265 perf_event_ctx_lock_nested(struct perf_event *event, int nesting) 1266 { 1267 struct perf_event_context *ctx; 1268 1269 again: 1270 rcu_read_lock(); 1271 ctx = READ_ONCE(event->ctx); 1272 if (!refcount_inc_not_zero(&ctx->refcount)) { 1273 rcu_read_unlock(); 1274 goto again; 1275 } 1276 rcu_read_unlock(); 1277 1278 mutex_lock_nested(&ctx->mutex, nesting); 1279 if (event->ctx != ctx) { 1280 mutex_unlock(&ctx->mutex); 1281 put_ctx(ctx); 1282 goto again; 1283 } 1284 1285 return ctx; 1286 } 1287 1288 static inline struct perf_event_context * 1289 perf_event_ctx_lock(struct perf_event *event) 1290 { 1291 return perf_event_ctx_lock_nested(event, 0); 1292 } 1293 1294 static void perf_event_ctx_unlock(struct perf_event *event, 1295 struct perf_event_context *ctx) 1296 { 1297 mutex_unlock(&ctx->mutex); 1298 put_ctx(ctx); 1299 } 1300 1301 /* 1302 * This must be done under the ctx->lock, such as to serialize against 1303 * context_equiv(), therefore we cannot call put_ctx() since that might end up 1304 * calling scheduler related locks and ctx->lock nests inside those. 1305 */ 1306 static __must_check struct perf_event_context * 1307 unclone_ctx(struct perf_event_context *ctx) 1308 { 1309 struct perf_event_context *parent_ctx = ctx->parent_ctx; 1310 1311 lockdep_assert_held(&ctx->lock); 1312 1313 if (parent_ctx) 1314 ctx->parent_ctx = NULL; 1315 ctx->generation++; 1316 1317 return parent_ctx; 1318 } 1319 1320 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p, 1321 enum pid_type type) 1322 { 1323 u32 nr; 1324 /* 1325 * only top level events have the pid namespace they were created in 1326 */ 1327 if (event->parent) 1328 event = event->parent; 1329 1330 nr = __task_pid_nr_ns(p, type, event->ns); 1331 /* avoid -1 if it is idle thread or runs in another ns */ 1332 if (!nr && !pid_alive(p)) 1333 nr = -1; 1334 return nr; 1335 } 1336 1337 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) 1338 { 1339 return perf_event_pid_type(event, p, PIDTYPE_TGID); 1340 } 1341 1342 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) 1343 { 1344 return perf_event_pid_type(event, p, PIDTYPE_PID); 1345 } 1346 1347 /* 1348 * If we inherit events we want to return the parent event id 1349 * to userspace. 1350 */ 1351 static u64 primary_event_id(struct perf_event *event) 1352 { 1353 u64 id = event->id; 1354 1355 if (event->parent) 1356 id = event->parent->id; 1357 1358 return id; 1359 } 1360 1361 /* 1362 * Get the perf_event_context for a task and lock it. 1363 * 1364 * This has to cope with with the fact that until it is locked, 1365 * the context could get moved to another task. 1366 */ 1367 static struct perf_event_context * 1368 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags) 1369 { 1370 struct perf_event_context *ctx; 1371 1372 retry: 1373 /* 1374 * One of the few rules of preemptible RCU is that one cannot do 1375 * rcu_read_unlock() while holding a scheduler (or nested) lock when 1376 * part of the read side critical section was irqs-enabled -- see 1377 * rcu_read_unlock_special(). 1378 * 1379 * Since ctx->lock nests under rq->lock we must ensure the entire read 1380 * side critical section has interrupts disabled. 1381 */ 1382 local_irq_save(*flags); 1383 rcu_read_lock(); 1384 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]); 1385 if (ctx) { 1386 /* 1387 * If this context is a clone of another, it might 1388 * get swapped for another underneath us by 1389 * perf_event_task_sched_out, though the 1390 * rcu_read_lock() protects us from any context 1391 * getting freed. Lock the context and check if it 1392 * got swapped before we could get the lock, and retry 1393 * if so. If we locked the right context, then it 1394 * can't get swapped on us any more. 1395 */ 1396 raw_spin_lock(&ctx->lock); 1397 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) { 1398 raw_spin_unlock(&ctx->lock); 1399 rcu_read_unlock(); 1400 local_irq_restore(*flags); 1401 goto retry; 1402 } 1403 1404 if (ctx->task == TASK_TOMBSTONE || 1405 !refcount_inc_not_zero(&ctx->refcount)) { 1406 raw_spin_unlock(&ctx->lock); 1407 ctx = NULL; 1408 } else { 1409 WARN_ON_ONCE(ctx->task != task); 1410 } 1411 } 1412 rcu_read_unlock(); 1413 if (!ctx) 1414 local_irq_restore(*flags); 1415 return ctx; 1416 } 1417 1418 /* 1419 * Get the context for a task and increment its pin_count so it 1420 * can't get swapped to another task. This also increments its 1421 * reference count so that the context can't get freed. 1422 */ 1423 static struct perf_event_context * 1424 perf_pin_task_context(struct task_struct *task, int ctxn) 1425 { 1426 struct perf_event_context *ctx; 1427 unsigned long flags; 1428 1429 ctx = perf_lock_task_context(task, ctxn, &flags); 1430 if (ctx) { 1431 ++ctx->pin_count; 1432 raw_spin_unlock_irqrestore(&ctx->lock, flags); 1433 } 1434 return ctx; 1435 } 1436 1437 static void perf_unpin_context(struct perf_event_context *ctx) 1438 { 1439 unsigned long flags; 1440 1441 raw_spin_lock_irqsave(&ctx->lock, flags); 1442 --ctx->pin_count; 1443 raw_spin_unlock_irqrestore(&ctx->lock, flags); 1444 } 1445 1446 /* 1447 * Update the record of the current time in a context. 1448 */ 1449 static void update_context_time(struct perf_event_context *ctx) 1450 { 1451 u64 now = perf_clock(); 1452 1453 ctx->time += now - ctx->timestamp; 1454 ctx->timestamp = now; 1455 } 1456 1457 static u64 perf_event_time(struct perf_event *event) 1458 { 1459 struct perf_event_context *ctx = event->ctx; 1460 1461 if (is_cgroup_event(event)) 1462 return perf_cgroup_event_time(event); 1463 1464 return ctx ? ctx->time : 0; 1465 } 1466 1467 static enum event_type_t get_event_type(struct perf_event *event) 1468 { 1469 struct perf_event_context *ctx = event->ctx; 1470 enum event_type_t event_type; 1471 1472 lockdep_assert_held(&ctx->lock); 1473 1474 /* 1475 * It's 'group type', really, because if our group leader is 1476 * pinned, so are we. 1477 */ 1478 if (event->group_leader != event) 1479 event = event->group_leader; 1480 1481 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE; 1482 if (!ctx->task) 1483 event_type |= EVENT_CPU; 1484 1485 return event_type; 1486 } 1487 1488 /* 1489 * Helper function to initialize event group nodes. 1490 */ 1491 static void init_event_group(struct perf_event *event) 1492 { 1493 RB_CLEAR_NODE(&event->group_node); 1494 event->group_index = 0; 1495 } 1496 1497 /* 1498 * Extract pinned or flexible groups from the context 1499 * based on event attrs bits. 1500 */ 1501 static struct perf_event_groups * 1502 get_event_groups(struct perf_event *event, struct perf_event_context *ctx) 1503 { 1504 if (event->attr.pinned) 1505 return &ctx->pinned_groups; 1506 else 1507 return &ctx->flexible_groups; 1508 } 1509 1510 /* 1511 * Helper function to initializes perf_event_group trees. 1512 */ 1513 static void perf_event_groups_init(struct perf_event_groups *groups) 1514 { 1515 groups->tree = RB_ROOT; 1516 groups->index = 0; 1517 } 1518 1519 /* 1520 * Compare function for event groups; 1521 * 1522 * Implements complex key that first sorts by CPU and then by virtual index 1523 * which provides ordering when rotating groups for the same CPU. 1524 */ 1525 static bool 1526 perf_event_groups_less(struct perf_event *left, struct perf_event *right) 1527 { 1528 if (left->cpu < right->cpu) 1529 return true; 1530 if (left->cpu > right->cpu) 1531 return false; 1532 1533 if (left->group_index < right->group_index) 1534 return true; 1535 if (left->group_index > right->group_index) 1536 return false; 1537 1538 return false; 1539 } 1540 1541 /* 1542 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for 1543 * key (see perf_event_groups_less). This places it last inside the CPU 1544 * subtree. 1545 */ 1546 static void 1547 perf_event_groups_insert(struct perf_event_groups *groups, 1548 struct perf_event *event) 1549 { 1550 struct perf_event *node_event; 1551 struct rb_node *parent; 1552 struct rb_node **node; 1553 1554 event->group_index = ++groups->index; 1555 1556 node = &groups->tree.rb_node; 1557 parent = *node; 1558 1559 while (*node) { 1560 parent = *node; 1561 node_event = container_of(*node, struct perf_event, group_node); 1562 1563 if (perf_event_groups_less(event, node_event)) 1564 node = &parent->rb_left; 1565 else 1566 node = &parent->rb_right; 1567 } 1568 1569 rb_link_node(&event->group_node, parent, node); 1570 rb_insert_color(&event->group_node, &groups->tree); 1571 } 1572 1573 /* 1574 * Helper function to insert event into the pinned or flexible groups. 1575 */ 1576 static void 1577 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx) 1578 { 1579 struct perf_event_groups *groups; 1580 1581 groups = get_event_groups(event, ctx); 1582 perf_event_groups_insert(groups, event); 1583 } 1584 1585 /* 1586 * Delete a group from a tree. 1587 */ 1588 static void 1589 perf_event_groups_delete(struct perf_event_groups *groups, 1590 struct perf_event *event) 1591 { 1592 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) || 1593 RB_EMPTY_ROOT(&groups->tree)); 1594 1595 rb_erase(&event->group_node, &groups->tree); 1596 init_event_group(event); 1597 } 1598 1599 /* 1600 * Helper function to delete event from its groups. 1601 */ 1602 static void 1603 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx) 1604 { 1605 struct perf_event_groups *groups; 1606 1607 groups = get_event_groups(event, ctx); 1608 perf_event_groups_delete(groups, event); 1609 } 1610 1611 /* 1612 * Get the leftmost event in the @cpu subtree. 1613 */ 1614 static struct perf_event * 1615 perf_event_groups_first(struct perf_event_groups *groups, int cpu) 1616 { 1617 struct perf_event *node_event = NULL, *match = NULL; 1618 struct rb_node *node = groups->tree.rb_node; 1619 1620 while (node) { 1621 node_event = container_of(node, struct perf_event, group_node); 1622 1623 if (cpu < node_event->cpu) { 1624 node = node->rb_left; 1625 } else if (cpu > node_event->cpu) { 1626 node = node->rb_right; 1627 } else { 1628 match = node_event; 1629 node = node->rb_left; 1630 } 1631 } 1632 1633 return match; 1634 } 1635 1636 /* 1637 * Like rb_entry_next_safe() for the @cpu subtree. 1638 */ 1639 static struct perf_event * 1640 perf_event_groups_next(struct perf_event *event) 1641 { 1642 struct perf_event *next; 1643 1644 next = rb_entry_safe(rb_next(&event->group_node), typeof(*event), group_node); 1645 if (next && next->cpu == event->cpu) 1646 return next; 1647 1648 return NULL; 1649 } 1650 1651 /* 1652 * Iterate through the whole groups tree. 1653 */ 1654 #define perf_event_groups_for_each(event, groups) \ 1655 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \ 1656 typeof(*event), group_node); event; \ 1657 event = rb_entry_safe(rb_next(&event->group_node), \ 1658 typeof(*event), group_node)) 1659 1660 /* 1661 * Add an event from the lists for its context. 1662 * Must be called with ctx->mutex and ctx->lock held. 1663 */ 1664 static void 1665 list_add_event(struct perf_event *event, struct perf_event_context *ctx) 1666 { 1667 lockdep_assert_held(&ctx->lock); 1668 1669 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); 1670 event->attach_state |= PERF_ATTACH_CONTEXT; 1671 1672 event->tstamp = perf_event_time(event); 1673 1674 /* 1675 * If we're a stand alone event or group leader, we go to the context 1676 * list, group events are kept attached to the group so that 1677 * perf_group_detach can, at all times, locate all siblings. 1678 */ 1679 if (event->group_leader == event) { 1680 event->group_caps = event->event_caps; 1681 add_event_to_groups(event, ctx); 1682 } 1683 1684 list_update_cgroup_event(event, ctx, true); 1685 1686 list_add_rcu(&event->event_entry, &ctx->event_list); 1687 ctx->nr_events++; 1688 if (event->attr.inherit_stat) 1689 ctx->nr_stat++; 1690 1691 ctx->generation++; 1692 } 1693 1694 /* 1695 * Initialize event state based on the perf_event_attr::disabled. 1696 */ 1697 static inline void perf_event__state_init(struct perf_event *event) 1698 { 1699 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF : 1700 PERF_EVENT_STATE_INACTIVE; 1701 } 1702 1703 static void __perf_event_read_size(struct perf_event *event, int nr_siblings) 1704 { 1705 int entry = sizeof(u64); /* value */ 1706 int size = 0; 1707 int nr = 1; 1708 1709 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 1710 size += sizeof(u64); 1711 1712 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 1713 size += sizeof(u64); 1714 1715 if (event->attr.read_format & PERF_FORMAT_ID) 1716 entry += sizeof(u64); 1717 1718 if (event->attr.read_format & PERF_FORMAT_GROUP) { 1719 nr += nr_siblings; 1720 size += sizeof(u64); 1721 } 1722 1723 size += entry * nr; 1724 event->read_size = size; 1725 } 1726 1727 static void __perf_event_header_size(struct perf_event *event, u64 sample_type) 1728 { 1729 struct perf_sample_data *data; 1730 u16 size = 0; 1731 1732 if (sample_type & PERF_SAMPLE_IP) 1733 size += sizeof(data->ip); 1734 1735 if (sample_type & PERF_SAMPLE_ADDR) 1736 size += sizeof(data->addr); 1737 1738 if (sample_type & PERF_SAMPLE_PERIOD) 1739 size += sizeof(data->period); 1740 1741 if (sample_type & PERF_SAMPLE_WEIGHT) 1742 size += sizeof(data->weight); 1743 1744 if (sample_type & PERF_SAMPLE_READ) 1745 size += event->read_size; 1746 1747 if (sample_type & PERF_SAMPLE_DATA_SRC) 1748 size += sizeof(data->data_src.val); 1749 1750 if (sample_type & PERF_SAMPLE_TRANSACTION) 1751 size += sizeof(data->txn); 1752 1753 if (sample_type & PERF_SAMPLE_PHYS_ADDR) 1754 size += sizeof(data->phys_addr); 1755 1756 event->header_size = size; 1757 } 1758 1759 /* 1760 * Called at perf_event creation and when events are attached/detached from a 1761 * group. 1762 */ 1763 static void perf_event__header_size(struct perf_event *event) 1764 { 1765 __perf_event_read_size(event, 1766 event->group_leader->nr_siblings); 1767 __perf_event_header_size(event, event->attr.sample_type); 1768 } 1769 1770 static void perf_event__id_header_size(struct perf_event *event) 1771 { 1772 struct perf_sample_data *data; 1773 u64 sample_type = event->attr.sample_type; 1774 u16 size = 0; 1775 1776 if (sample_type & PERF_SAMPLE_TID) 1777 size += sizeof(data->tid_entry); 1778 1779 if (sample_type & PERF_SAMPLE_TIME) 1780 size += sizeof(data->time); 1781 1782 if (sample_type & PERF_SAMPLE_IDENTIFIER) 1783 size += sizeof(data->id); 1784 1785 if (sample_type & PERF_SAMPLE_ID) 1786 size += sizeof(data->id); 1787 1788 if (sample_type & PERF_SAMPLE_STREAM_ID) 1789 size += sizeof(data->stream_id); 1790 1791 if (sample_type & PERF_SAMPLE_CPU) 1792 size += sizeof(data->cpu_entry); 1793 1794 event->id_header_size = size; 1795 } 1796 1797 static bool perf_event_validate_size(struct perf_event *event) 1798 { 1799 /* 1800 * The values computed here will be over-written when we actually 1801 * attach the event. 1802 */ 1803 __perf_event_read_size(event, event->group_leader->nr_siblings + 1); 1804 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ); 1805 perf_event__id_header_size(event); 1806 1807 /* 1808 * Sum the lot; should not exceed the 64k limit we have on records. 1809 * Conservative limit to allow for callchains and other variable fields. 1810 */ 1811 if (event->read_size + event->header_size + 1812 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024) 1813 return false; 1814 1815 return true; 1816 } 1817 1818 static void perf_group_attach(struct perf_event *event) 1819 { 1820 struct perf_event *group_leader = event->group_leader, *pos; 1821 1822 lockdep_assert_held(&event->ctx->lock); 1823 1824 /* 1825 * We can have double attach due to group movement in perf_event_open. 1826 */ 1827 if (event->attach_state & PERF_ATTACH_GROUP) 1828 return; 1829 1830 event->attach_state |= PERF_ATTACH_GROUP; 1831 1832 if (group_leader == event) 1833 return; 1834 1835 WARN_ON_ONCE(group_leader->ctx != event->ctx); 1836 1837 group_leader->group_caps &= event->event_caps; 1838 1839 list_add_tail(&event->sibling_list, &group_leader->sibling_list); 1840 group_leader->nr_siblings++; 1841 1842 perf_event__header_size(group_leader); 1843 1844 for_each_sibling_event(pos, group_leader) 1845 perf_event__header_size(pos); 1846 } 1847 1848 /* 1849 * Remove an event from the lists for its context. 1850 * Must be called with ctx->mutex and ctx->lock held. 1851 */ 1852 static void 1853 list_del_event(struct perf_event *event, struct perf_event_context *ctx) 1854 { 1855 WARN_ON_ONCE(event->ctx != ctx); 1856 lockdep_assert_held(&ctx->lock); 1857 1858 /* 1859 * We can have double detach due to exit/hot-unplug + close. 1860 */ 1861 if (!(event->attach_state & PERF_ATTACH_CONTEXT)) 1862 return; 1863 1864 event->attach_state &= ~PERF_ATTACH_CONTEXT; 1865 1866 list_update_cgroup_event(event, ctx, false); 1867 1868 ctx->nr_events--; 1869 if (event->attr.inherit_stat) 1870 ctx->nr_stat--; 1871 1872 list_del_rcu(&event->event_entry); 1873 1874 if (event->group_leader == event) 1875 del_event_from_groups(event, ctx); 1876 1877 /* 1878 * If event was in error state, then keep it 1879 * that way, otherwise bogus counts will be 1880 * returned on read(). The only way to get out 1881 * of error state is by explicit re-enabling 1882 * of the event 1883 */ 1884 if (event->state > PERF_EVENT_STATE_OFF) 1885 perf_event_set_state(event, PERF_EVENT_STATE_OFF); 1886 1887 ctx->generation++; 1888 } 1889 1890 static int 1891 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event) 1892 { 1893 if (!has_aux(aux_event)) 1894 return 0; 1895 1896 if (!event->pmu->aux_output_match) 1897 return 0; 1898 1899 return event->pmu->aux_output_match(aux_event); 1900 } 1901 1902 static void put_event(struct perf_event *event); 1903 static void event_sched_out(struct perf_event *event, 1904 struct perf_cpu_context *cpuctx, 1905 struct perf_event_context *ctx); 1906 1907 static void perf_put_aux_event(struct perf_event *event) 1908 { 1909 struct perf_event_context *ctx = event->ctx; 1910 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 1911 struct perf_event *iter; 1912 1913 /* 1914 * If event uses aux_event tear down the link 1915 */ 1916 if (event->aux_event) { 1917 iter = event->aux_event; 1918 event->aux_event = NULL; 1919 put_event(iter); 1920 return; 1921 } 1922 1923 /* 1924 * If the event is an aux_event, tear down all links to 1925 * it from other events. 1926 */ 1927 for_each_sibling_event(iter, event->group_leader) { 1928 if (iter->aux_event != event) 1929 continue; 1930 1931 iter->aux_event = NULL; 1932 put_event(event); 1933 1934 /* 1935 * If it's ACTIVE, schedule it out and put it into ERROR 1936 * state so that we don't try to schedule it again. Note 1937 * that perf_event_enable() will clear the ERROR status. 1938 */ 1939 event_sched_out(iter, cpuctx, ctx); 1940 perf_event_set_state(event, PERF_EVENT_STATE_ERROR); 1941 } 1942 } 1943 1944 static int perf_get_aux_event(struct perf_event *event, 1945 struct perf_event *group_leader) 1946 { 1947 /* 1948 * Our group leader must be an aux event if we want to be 1949 * an aux_output. This way, the aux event will precede its 1950 * aux_output events in the group, and therefore will always 1951 * schedule first. 1952 */ 1953 if (!group_leader) 1954 return 0; 1955 1956 if (!perf_aux_output_match(event, group_leader)) 1957 return 0; 1958 1959 if (!atomic_long_inc_not_zero(&group_leader->refcount)) 1960 return 0; 1961 1962 /* 1963 * Link aux_outputs to their aux event; this is undone in 1964 * perf_group_detach() by perf_put_aux_event(). When the 1965 * group in torn down, the aux_output events loose their 1966 * link to the aux_event and can't schedule any more. 1967 */ 1968 event->aux_event = group_leader; 1969 1970 return 1; 1971 } 1972 1973 static void perf_group_detach(struct perf_event *event) 1974 { 1975 struct perf_event *sibling, *tmp; 1976 struct perf_event_context *ctx = event->ctx; 1977 1978 lockdep_assert_held(&ctx->lock); 1979 1980 /* 1981 * We can have double detach due to exit/hot-unplug + close. 1982 */ 1983 if (!(event->attach_state & PERF_ATTACH_GROUP)) 1984 return; 1985 1986 event->attach_state &= ~PERF_ATTACH_GROUP; 1987 1988 perf_put_aux_event(event); 1989 1990 /* 1991 * If this is a sibling, remove it from its group. 1992 */ 1993 if (event->group_leader != event) { 1994 list_del_init(&event->sibling_list); 1995 event->group_leader->nr_siblings--; 1996 goto out; 1997 } 1998 1999 /* 2000 * If this was a group event with sibling events then 2001 * upgrade the siblings to singleton events by adding them 2002 * to whatever list we are on. 2003 */ 2004 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) { 2005 2006 sibling->group_leader = sibling; 2007 list_del_init(&sibling->sibling_list); 2008 2009 /* Inherit group flags from the previous leader */ 2010 sibling->group_caps = event->group_caps; 2011 2012 if (!RB_EMPTY_NODE(&event->group_node)) { 2013 add_event_to_groups(sibling, event->ctx); 2014 2015 if (sibling->state == PERF_EVENT_STATE_ACTIVE) { 2016 struct list_head *list = sibling->attr.pinned ? 2017 &ctx->pinned_active : &ctx->flexible_active; 2018 2019 list_add_tail(&sibling->active_list, list); 2020 } 2021 } 2022 2023 WARN_ON_ONCE(sibling->ctx != event->ctx); 2024 } 2025 2026 out: 2027 perf_event__header_size(event->group_leader); 2028 2029 for_each_sibling_event(tmp, event->group_leader) 2030 perf_event__header_size(tmp); 2031 } 2032 2033 static bool is_orphaned_event(struct perf_event *event) 2034 { 2035 return event->state == PERF_EVENT_STATE_DEAD; 2036 } 2037 2038 static inline int __pmu_filter_match(struct perf_event *event) 2039 { 2040 struct pmu *pmu = event->pmu; 2041 return pmu->filter_match ? pmu->filter_match(event) : 1; 2042 } 2043 2044 /* 2045 * Check whether we should attempt to schedule an event group based on 2046 * PMU-specific filtering. An event group can consist of HW and SW events, 2047 * potentially with a SW leader, so we must check all the filters, to 2048 * determine whether a group is schedulable: 2049 */ 2050 static inline int pmu_filter_match(struct perf_event *event) 2051 { 2052 struct perf_event *sibling; 2053 2054 if (!__pmu_filter_match(event)) 2055 return 0; 2056 2057 for_each_sibling_event(sibling, event) { 2058 if (!__pmu_filter_match(sibling)) 2059 return 0; 2060 } 2061 2062 return 1; 2063 } 2064 2065 static inline int 2066 event_filter_match(struct perf_event *event) 2067 { 2068 return (event->cpu == -1 || event->cpu == smp_processor_id()) && 2069 perf_cgroup_match(event) && pmu_filter_match(event); 2070 } 2071 2072 static void 2073 event_sched_out(struct perf_event *event, 2074 struct perf_cpu_context *cpuctx, 2075 struct perf_event_context *ctx) 2076 { 2077 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE; 2078 2079 WARN_ON_ONCE(event->ctx != ctx); 2080 lockdep_assert_held(&ctx->lock); 2081 2082 if (event->state != PERF_EVENT_STATE_ACTIVE) 2083 return; 2084 2085 /* 2086 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but 2087 * we can schedule events _OUT_ individually through things like 2088 * __perf_remove_from_context(). 2089 */ 2090 list_del_init(&event->active_list); 2091 2092 perf_pmu_disable(event->pmu); 2093 2094 event->pmu->del(event, 0); 2095 event->oncpu = -1; 2096 2097 if (READ_ONCE(event->pending_disable) >= 0) { 2098 WRITE_ONCE(event->pending_disable, -1); 2099 state = PERF_EVENT_STATE_OFF; 2100 } 2101 perf_event_set_state(event, state); 2102 2103 if (!is_software_event(event)) 2104 cpuctx->active_oncpu--; 2105 if (!--ctx->nr_active) 2106 perf_event_ctx_deactivate(ctx); 2107 if (event->attr.freq && event->attr.sample_freq) 2108 ctx->nr_freq--; 2109 if (event->attr.exclusive || !cpuctx->active_oncpu) 2110 cpuctx->exclusive = 0; 2111 2112 perf_pmu_enable(event->pmu); 2113 } 2114 2115 static void 2116 group_sched_out(struct perf_event *group_event, 2117 struct perf_cpu_context *cpuctx, 2118 struct perf_event_context *ctx) 2119 { 2120 struct perf_event *event; 2121 2122 if (group_event->state != PERF_EVENT_STATE_ACTIVE) 2123 return; 2124 2125 perf_pmu_disable(ctx->pmu); 2126 2127 event_sched_out(group_event, cpuctx, ctx); 2128 2129 /* 2130 * Schedule out siblings (if any): 2131 */ 2132 for_each_sibling_event(event, group_event) 2133 event_sched_out(event, cpuctx, ctx); 2134 2135 perf_pmu_enable(ctx->pmu); 2136 2137 if (group_event->attr.exclusive) 2138 cpuctx->exclusive = 0; 2139 } 2140 2141 #define DETACH_GROUP 0x01UL 2142 2143 /* 2144 * Cross CPU call to remove a performance event 2145 * 2146 * We disable the event on the hardware level first. After that we 2147 * remove it from the context list. 2148 */ 2149 static void 2150 __perf_remove_from_context(struct perf_event *event, 2151 struct perf_cpu_context *cpuctx, 2152 struct perf_event_context *ctx, 2153 void *info) 2154 { 2155 unsigned long flags = (unsigned long)info; 2156 2157 if (ctx->is_active & EVENT_TIME) { 2158 update_context_time(ctx); 2159 update_cgrp_time_from_cpuctx(cpuctx); 2160 } 2161 2162 event_sched_out(event, cpuctx, ctx); 2163 if (flags & DETACH_GROUP) 2164 perf_group_detach(event); 2165 list_del_event(event, ctx); 2166 2167 if (!ctx->nr_events && ctx->is_active) { 2168 ctx->is_active = 0; 2169 if (ctx->task) { 2170 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 2171 cpuctx->task_ctx = NULL; 2172 } 2173 } 2174 } 2175 2176 /* 2177 * Remove the event from a task's (or a CPU's) list of events. 2178 * 2179 * If event->ctx is a cloned context, callers must make sure that 2180 * every task struct that event->ctx->task could possibly point to 2181 * remains valid. This is OK when called from perf_release since 2182 * that only calls us on the top-level context, which can't be a clone. 2183 * When called from perf_event_exit_task, it's OK because the 2184 * context has been detached from its task. 2185 */ 2186 static void perf_remove_from_context(struct perf_event *event, unsigned long flags) 2187 { 2188 struct perf_event_context *ctx = event->ctx; 2189 2190 lockdep_assert_held(&ctx->mutex); 2191 2192 event_function_call(event, __perf_remove_from_context, (void *)flags); 2193 2194 /* 2195 * The above event_function_call() can NO-OP when it hits 2196 * TASK_TOMBSTONE. In that case we must already have been detached 2197 * from the context (by perf_event_exit_event()) but the grouping 2198 * might still be in-tact. 2199 */ 2200 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); 2201 if ((flags & DETACH_GROUP) && 2202 (event->attach_state & PERF_ATTACH_GROUP)) { 2203 /* 2204 * Since in that case we cannot possibly be scheduled, simply 2205 * detach now. 2206 */ 2207 raw_spin_lock_irq(&ctx->lock); 2208 perf_group_detach(event); 2209 raw_spin_unlock_irq(&ctx->lock); 2210 } 2211 } 2212 2213 /* 2214 * Cross CPU call to disable a performance event 2215 */ 2216 static void __perf_event_disable(struct perf_event *event, 2217 struct perf_cpu_context *cpuctx, 2218 struct perf_event_context *ctx, 2219 void *info) 2220 { 2221 if (event->state < PERF_EVENT_STATE_INACTIVE) 2222 return; 2223 2224 if (ctx->is_active & EVENT_TIME) { 2225 update_context_time(ctx); 2226 update_cgrp_time_from_event(event); 2227 } 2228 2229 if (event == event->group_leader) 2230 group_sched_out(event, cpuctx, ctx); 2231 else 2232 event_sched_out(event, cpuctx, ctx); 2233 2234 perf_event_set_state(event, PERF_EVENT_STATE_OFF); 2235 } 2236 2237 /* 2238 * Disable an event. 2239 * 2240 * If event->ctx is a cloned context, callers must make sure that 2241 * every task struct that event->ctx->task could possibly point to 2242 * remains valid. This condition is satisfied when called through 2243 * perf_event_for_each_child or perf_event_for_each because they 2244 * hold the top-level event's child_mutex, so any descendant that 2245 * goes to exit will block in perf_event_exit_event(). 2246 * 2247 * When called from perf_pending_event it's OK because event->ctx 2248 * is the current context on this CPU and preemption is disabled, 2249 * hence we can't get into perf_event_task_sched_out for this context. 2250 */ 2251 static void _perf_event_disable(struct perf_event *event) 2252 { 2253 struct perf_event_context *ctx = event->ctx; 2254 2255 raw_spin_lock_irq(&ctx->lock); 2256 if (event->state <= PERF_EVENT_STATE_OFF) { 2257 raw_spin_unlock_irq(&ctx->lock); 2258 return; 2259 } 2260 raw_spin_unlock_irq(&ctx->lock); 2261 2262 event_function_call(event, __perf_event_disable, NULL); 2263 } 2264 2265 void perf_event_disable_local(struct perf_event *event) 2266 { 2267 event_function_local(event, __perf_event_disable, NULL); 2268 } 2269 2270 /* 2271 * Strictly speaking kernel users cannot create groups and therefore this 2272 * interface does not need the perf_event_ctx_lock() magic. 2273 */ 2274 void perf_event_disable(struct perf_event *event) 2275 { 2276 struct perf_event_context *ctx; 2277 2278 ctx = perf_event_ctx_lock(event); 2279 _perf_event_disable(event); 2280 perf_event_ctx_unlock(event, ctx); 2281 } 2282 EXPORT_SYMBOL_GPL(perf_event_disable); 2283 2284 void perf_event_disable_inatomic(struct perf_event *event) 2285 { 2286 WRITE_ONCE(event->pending_disable, smp_processor_id()); 2287 /* can fail, see perf_pending_event_disable() */ 2288 irq_work_queue(&event->pending); 2289 } 2290 2291 static void perf_set_shadow_time(struct perf_event *event, 2292 struct perf_event_context *ctx) 2293 { 2294 /* 2295 * use the correct time source for the time snapshot 2296 * 2297 * We could get by without this by leveraging the 2298 * fact that to get to this function, the caller 2299 * has most likely already called update_context_time() 2300 * and update_cgrp_time_xx() and thus both timestamp 2301 * are identical (or very close). Given that tstamp is, 2302 * already adjusted for cgroup, we could say that: 2303 * tstamp - ctx->timestamp 2304 * is equivalent to 2305 * tstamp - cgrp->timestamp. 2306 * 2307 * Then, in perf_output_read(), the calculation would 2308 * work with no changes because: 2309 * - event is guaranteed scheduled in 2310 * - no scheduled out in between 2311 * - thus the timestamp would be the same 2312 * 2313 * But this is a bit hairy. 2314 * 2315 * So instead, we have an explicit cgroup call to remain 2316 * within the time time source all along. We believe it 2317 * is cleaner and simpler to understand. 2318 */ 2319 if (is_cgroup_event(event)) 2320 perf_cgroup_set_shadow_time(event, event->tstamp); 2321 else 2322 event->shadow_ctx_time = event->tstamp - ctx->timestamp; 2323 } 2324 2325 #define MAX_INTERRUPTS (~0ULL) 2326 2327 static void perf_log_throttle(struct perf_event *event, int enable); 2328 static void perf_log_itrace_start(struct perf_event *event); 2329 2330 static int 2331 event_sched_in(struct perf_event *event, 2332 struct perf_cpu_context *cpuctx, 2333 struct perf_event_context *ctx) 2334 { 2335 int ret = 0; 2336 2337 lockdep_assert_held(&ctx->lock); 2338 2339 if (event->state <= PERF_EVENT_STATE_OFF) 2340 return 0; 2341 2342 WRITE_ONCE(event->oncpu, smp_processor_id()); 2343 /* 2344 * Order event::oncpu write to happen before the ACTIVE state is 2345 * visible. This allows perf_event_{stop,read}() to observe the correct 2346 * ->oncpu if it sees ACTIVE. 2347 */ 2348 smp_wmb(); 2349 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE); 2350 2351 /* 2352 * Unthrottle events, since we scheduled we might have missed several 2353 * ticks already, also for a heavily scheduling task there is little 2354 * guarantee it'll get a tick in a timely manner. 2355 */ 2356 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) { 2357 perf_log_throttle(event, 1); 2358 event->hw.interrupts = 0; 2359 } 2360 2361 perf_pmu_disable(event->pmu); 2362 2363 perf_set_shadow_time(event, ctx); 2364 2365 perf_log_itrace_start(event); 2366 2367 if (event->pmu->add(event, PERF_EF_START)) { 2368 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE); 2369 event->oncpu = -1; 2370 ret = -EAGAIN; 2371 goto out; 2372 } 2373 2374 if (!is_software_event(event)) 2375 cpuctx->active_oncpu++; 2376 if (!ctx->nr_active++) 2377 perf_event_ctx_activate(ctx); 2378 if (event->attr.freq && event->attr.sample_freq) 2379 ctx->nr_freq++; 2380 2381 if (event->attr.exclusive) 2382 cpuctx->exclusive = 1; 2383 2384 out: 2385 perf_pmu_enable(event->pmu); 2386 2387 return ret; 2388 } 2389 2390 static int 2391 group_sched_in(struct perf_event *group_event, 2392 struct perf_cpu_context *cpuctx, 2393 struct perf_event_context *ctx) 2394 { 2395 struct perf_event *event, *partial_group = NULL; 2396 struct pmu *pmu = ctx->pmu; 2397 2398 if (group_event->state == PERF_EVENT_STATE_OFF) 2399 return 0; 2400 2401 pmu->start_txn(pmu, PERF_PMU_TXN_ADD); 2402 2403 if (event_sched_in(group_event, cpuctx, ctx)) { 2404 pmu->cancel_txn(pmu); 2405 perf_mux_hrtimer_restart(cpuctx); 2406 return -EAGAIN; 2407 } 2408 2409 /* 2410 * Schedule in siblings as one group (if any): 2411 */ 2412 for_each_sibling_event(event, group_event) { 2413 if (event_sched_in(event, cpuctx, ctx)) { 2414 partial_group = event; 2415 goto group_error; 2416 } 2417 } 2418 2419 if (!pmu->commit_txn(pmu)) 2420 return 0; 2421 2422 group_error: 2423 /* 2424 * Groups can be scheduled in as one unit only, so undo any 2425 * partial group before returning: 2426 * The events up to the failed event are scheduled out normally. 2427 */ 2428 for_each_sibling_event(event, group_event) { 2429 if (event == partial_group) 2430 break; 2431 2432 event_sched_out(event, cpuctx, ctx); 2433 } 2434 event_sched_out(group_event, cpuctx, ctx); 2435 2436 pmu->cancel_txn(pmu); 2437 2438 perf_mux_hrtimer_restart(cpuctx); 2439 2440 return -EAGAIN; 2441 } 2442 2443 /* 2444 * Work out whether we can put this event group on the CPU now. 2445 */ 2446 static int group_can_go_on(struct perf_event *event, 2447 struct perf_cpu_context *cpuctx, 2448 int can_add_hw) 2449 { 2450 /* 2451 * Groups consisting entirely of software events can always go on. 2452 */ 2453 if (event->group_caps & PERF_EV_CAP_SOFTWARE) 2454 return 1; 2455 /* 2456 * If an exclusive group is already on, no other hardware 2457 * events can go on. 2458 */ 2459 if (cpuctx->exclusive) 2460 return 0; 2461 /* 2462 * If this group is exclusive and there are already 2463 * events on the CPU, it can't go on. 2464 */ 2465 if (event->attr.exclusive && cpuctx->active_oncpu) 2466 return 0; 2467 /* 2468 * Otherwise, try to add it if all previous groups were able 2469 * to go on. 2470 */ 2471 return can_add_hw; 2472 } 2473 2474 static void add_event_to_ctx(struct perf_event *event, 2475 struct perf_event_context *ctx) 2476 { 2477 list_add_event(event, ctx); 2478 perf_group_attach(event); 2479 } 2480 2481 static void ctx_sched_out(struct perf_event_context *ctx, 2482 struct perf_cpu_context *cpuctx, 2483 enum event_type_t event_type); 2484 static void 2485 ctx_sched_in(struct perf_event_context *ctx, 2486 struct perf_cpu_context *cpuctx, 2487 enum event_type_t event_type, 2488 struct task_struct *task); 2489 2490 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx, 2491 struct perf_event_context *ctx, 2492 enum event_type_t event_type) 2493 { 2494 if (!cpuctx->task_ctx) 2495 return; 2496 2497 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx)) 2498 return; 2499 2500 ctx_sched_out(ctx, cpuctx, event_type); 2501 } 2502 2503 static void perf_event_sched_in(struct perf_cpu_context *cpuctx, 2504 struct perf_event_context *ctx, 2505 struct task_struct *task) 2506 { 2507 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task); 2508 if (ctx) 2509 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task); 2510 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task); 2511 if (ctx) 2512 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task); 2513 } 2514 2515 /* 2516 * We want to maintain the following priority of scheduling: 2517 * - CPU pinned (EVENT_CPU | EVENT_PINNED) 2518 * - task pinned (EVENT_PINNED) 2519 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE) 2520 * - task flexible (EVENT_FLEXIBLE). 2521 * 2522 * In order to avoid unscheduling and scheduling back in everything every 2523 * time an event is added, only do it for the groups of equal priority and 2524 * below. 2525 * 2526 * This can be called after a batch operation on task events, in which case 2527 * event_type is a bit mask of the types of events involved. For CPU events, 2528 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE. 2529 */ 2530 static void ctx_resched(struct perf_cpu_context *cpuctx, 2531 struct perf_event_context *task_ctx, 2532 enum event_type_t event_type) 2533 { 2534 enum event_type_t ctx_event_type; 2535 bool cpu_event = !!(event_type & EVENT_CPU); 2536 2537 /* 2538 * If pinned groups are involved, flexible groups also need to be 2539 * scheduled out. 2540 */ 2541 if (event_type & EVENT_PINNED) 2542 event_type |= EVENT_FLEXIBLE; 2543 2544 ctx_event_type = event_type & EVENT_ALL; 2545 2546 perf_pmu_disable(cpuctx->ctx.pmu); 2547 if (task_ctx) 2548 task_ctx_sched_out(cpuctx, task_ctx, event_type); 2549 2550 /* 2551 * Decide which cpu ctx groups to schedule out based on the types 2552 * of events that caused rescheduling: 2553 * - EVENT_CPU: schedule out corresponding groups; 2554 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups; 2555 * - otherwise, do nothing more. 2556 */ 2557 if (cpu_event) 2558 cpu_ctx_sched_out(cpuctx, ctx_event_type); 2559 else if (ctx_event_type & EVENT_PINNED) 2560 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); 2561 2562 perf_event_sched_in(cpuctx, task_ctx, current); 2563 perf_pmu_enable(cpuctx->ctx.pmu); 2564 } 2565 2566 void perf_pmu_resched(struct pmu *pmu) 2567 { 2568 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 2569 struct perf_event_context *task_ctx = cpuctx->task_ctx; 2570 2571 perf_ctx_lock(cpuctx, task_ctx); 2572 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU); 2573 perf_ctx_unlock(cpuctx, task_ctx); 2574 } 2575 2576 /* 2577 * Cross CPU call to install and enable a performance event 2578 * 2579 * Very similar to remote_function() + event_function() but cannot assume that 2580 * things like ctx->is_active and cpuctx->task_ctx are set. 2581 */ 2582 static int __perf_install_in_context(void *info) 2583 { 2584 struct perf_event *event = info; 2585 struct perf_event_context *ctx = event->ctx; 2586 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 2587 struct perf_event_context *task_ctx = cpuctx->task_ctx; 2588 bool reprogram = true; 2589 int ret = 0; 2590 2591 raw_spin_lock(&cpuctx->ctx.lock); 2592 if (ctx->task) { 2593 raw_spin_lock(&ctx->lock); 2594 task_ctx = ctx; 2595 2596 reprogram = (ctx->task == current); 2597 2598 /* 2599 * If the task is running, it must be running on this CPU, 2600 * otherwise we cannot reprogram things. 2601 * 2602 * If its not running, we don't care, ctx->lock will 2603 * serialize against it becoming runnable. 2604 */ 2605 if (task_curr(ctx->task) && !reprogram) { 2606 ret = -ESRCH; 2607 goto unlock; 2608 } 2609 2610 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx); 2611 } else if (task_ctx) { 2612 raw_spin_lock(&task_ctx->lock); 2613 } 2614 2615 #ifdef CONFIG_CGROUP_PERF 2616 if (is_cgroup_event(event)) { 2617 /* 2618 * If the current cgroup doesn't match the event's 2619 * cgroup, we should not try to schedule it. 2620 */ 2621 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx); 2622 reprogram = cgroup_is_descendant(cgrp->css.cgroup, 2623 event->cgrp->css.cgroup); 2624 } 2625 #endif 2626 2627 if (reprogram) { 2628 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 2629 add_event_to_ctx(event, ctx); 2630 ctx_resched(cpuctx, task_ctx, get_event_type(event)); 2631 } else { 2632 add_event_to_ctx(event, ctx); 2633 } 2634 2635 unlock: 2636 perf_ctx_unlock(cpuctx, task_ctx); 2637 2638 return ret; 2639 } 2640 2641 static bool exclusive_event_installable(struct perf_event *event, 2642 struct perf_event_context *ctx); 2643 2644 /* 2645 * Attach a performance event to a context. 2646 * 2647 * Very similar to event_function_call, see comment there. 2648 */ 2649 static void 2650 perf_install_in_context(struct perf_event_context *ctx, 2651 struct perf_event *event, 2652 int cpu) 2653 { 2654 struct task_struct *task = READ_ONCE(ctx->task); 2655 2656 lockdep_assert_held(&ctx->mutex); 2657 2658 WARN_ON_ONCE(!exclusive_event_installable(event, ctx)); 2659 2660 if (event->cpu != -1) 2661 event->cpu = cpu; 2662 2663 /* 2664 * Ensures that if we can observe event->ctx, both the event and ctx 2665 * will be 'complete'. See perf_iterate_sb_cpu(). 2666 */ 2667 smp_store_release(&event->ctx, ctx); 2668 2669 if (!task) { 2670 cpu_function_call(cpu, __perf_install_in_context, event); 2671 return; 2672 } 2673 2674 /* 2675 * Should not happen, we validate the ctx is still alive before calling. 2676 */ 2677 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) 2678 return; 2679 2680 /* 2681 * Installing events is tricky because we cannot rely on ctx->is_active 2682 * to be set in case this is the nr_events 0 -> 1 transition. 2683 * 2684 * Instead we use task_curr(), which tells us if the task is running. 2685 * However, since we use task_curr() outside of rq::lock, we can race 2686 * against the actual state. This means the result can be wrong. 2687 * 2688 * If we get a false positive, we retry, this is harmless. 2689 * 2690 * If we get a false negative, things are complicated. If we are after 2691 * perf_event_context_sched_in() ctx::lock will serialize us, and the 2692 * value must be correct. If we're before, it doesn't matter since 2693 * perf_event_context_sched_in() will program the counter. 2694 * 2695 * However, this hinges on the remote context switch having observed 2696 * our task->perf_event_ctxp[] store, such that it will in fact take 2697 * ctx::lock in perf_event_context_sched_in(). 2698 * 2699 * We do this by task_function_call(), if the IPI fails to hit the task 2700 * we know any future context switch of task must see the 2701 * perf_event_ctpx[] store. 2702 */ 2703 2704 /* 2705 * This smp_mb() orders the task->perf_event_ctxp[] store with the 2706 * task_cpu() load, such that if the IPI then does not find the task 2707 * running, a future context switch of that task must observe the 2708 * store. 2709 */ 2710 smp_mb(); 2711 again: 2712 if (!task_function_call(task, __perf_install_in_context, event)) 2713 return; 2714 2715 raw_spin_lock_irq(&ctx->lock); 2716 task = ctx->task; 2717 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) { 2718 /* 2719 * Cannot happen because we already checked above (which also 2720 * cannot happen), and we hold ctx->mutex, which serializes us 2721 * against perf_event_exit_task_context(). 2722 */ 2723 raw_spin_unlock_irq(&ctx->lock); 2724 return; 2725 } 2726 /* 2727 * If the task is not running, ctx->lock will avoid it becoming so, 2728 * thus we can safely install the event. 2729 */ 2730 if (task_curr(task)) { 2731 raw_spin_unlock_irq(&ctx->lock); 2732 goto again; 2733 } 2734 add_event_to_ctx(event, ctx); 2735 raw_spin_unlock_irq(&ctx->lock); 2736 } 2737 2738 /* 2739 * Cross CPU call to enable a performance event 2740 */ 2741 static void __perf_event_enable(struct perf_event *event, 2742 struct perf_cpu_context *cpuctx, 2743 struct perf_event_context *ctx, 2744 void *info) 2745 { 2746 struct perf_event *leader = event->group_leader; 2747 struct perf_event_context *task_ctx; 2748 2749 if (event->state >= PERF_EVENT_STATE_INACTIVE || 2750 event->state <= PERF_EVENT_STATE_ERROR) 2751 return; 2752 2753 if (ctx->is_active) 2754 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 2755 2756 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE); 2757 2758 if (!ctx->is_active) 2759 return; 2760 2761 if (!event_filter_match(event)) { 2762 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current); 2763 return; 2764 } 2765 2766 /* 2767 * If the event is in a group and isn't the group leader, 2768 * then don't put it on unless the group is on. 2769 */ 2770 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) { 2771 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current); 2772 return; 2773 } 2774 2775 task_ctx = cpuctx->task_ctx; 2776 if (ctx->task) 2777 WARN_ON_ONCE(task_ctx != ctx); 2778 2779 ctx_resched(cpuctx, task_ctx, get_event_type(event)); 2780 } 2781 2782 /* 2783 * Enable an event. 2784 * 2785 * If event->ctx is a cloned context, callers must make sure that 2786 * every task struct that event->ctx->task could possibly point to 2787 * remains valid. This condition is satisfied when called through 2788 * perf_event_for_each_child or perf_event_for_each as described 2789 * for perf_event_disable. 2790 */ 2791 static void _perf_event_enable(struct perf_event *event) 2792 { 2793 struct perf_event_context *ctx = event->ctx; 2794 2795 raw_spin_lock_irq(&ctx->lock); 2796 if (event->state >= PERF_EVENT_STATE_INACTIVE || 2797 event->state < PERF_EVENT_STATE_ERROR) { 2798 raw_spin_unlock_irq(&ctx->lock); 2799 return; 2800 } 2801 2802 /* 2803 * If the event is in error state, clear that first. 2804 * 2805 * That way, if we see the event in error state below, we know that it 2806 * has gone back into error state, as distinct from the task having 2807 * been scheduled away before the cross-call arrived. 2808 */ 2809 if (event->state == PERF_EVENT_STATE_ERROR) 2810 event->state = PERF_EVENT_STATE_OFF; 2811 raw_spin_unlock_irq(&ctx->lock); 2812 2813 event_function_call(event, __perf_event_enable, NULL); 2814 } 2815 2816 /* 2817 * See perf_event_disable(); 2818 */ 2819 void perf_event_enable(struct perf_event *event) 2820 { 2821 struct perf_event_context *ctx; 2822 2823 ctx = perf_event_ctx_lock(event); 2824 _perf_event_enable(event); 2825 perf_event_ctx_unlock(event, ctx); 2826 } 2827 EXPORT_SYMBOL_GPL(perf_event_enable); 2828 2829 struct stop_event_data { 2830 struct perf_event *event; 2831 unsigned int restart; 2832 }; 2833 2834 static int __perf_event_stop(void *info) 2835 { 2836 struct stop_event_data *sd = info; 2837 struct perf_event *event = sd->event; 2838 2839 /* if it's already INACTIVE, do nothing */ 2840 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) 2841 return 0; 2842 2843 /* matches smp_wmb() in event_sched_in() */ 2844 smp_rmb(); 2845 2846 /* 2847 * There is a window with interrupts enabled before we get here, 2848 * so we need to check again lest we try to stop another CPU's event. 2849 */ 2850 if (READ_ONCE(event->oncpu) != smp_processor_id()) 2851 return -EAGAIN; 2852 2853 event->pmu->stop(event, PERF_EF_UPDATE); 2854 2855 /* 2856 * May race with the actual stop (through perf_pmu_output_stop()), 2857 * but it is only used for events with AUX ring buffer, and such 2858 * events will refuse to restart because of rb::aux_mmap_count==0, 2859 * see comments in perf_aux_output_begin(). 2860 * 2861 * Since this is happening on an event-local CPU, no trace is lost 2862 * while restarting. 2863 */ 2864 if (sd->restart) 2865 event->pmu->start(event, 0); 2866 2867 return 0; 2868 } 2869 2870 static int perf_event_stop(struct perf_event *event, int restart) 2871 { 2872 struct stop_event_data sd = { 2873 .event = event, 2874 .restart = restart, 2875 }; 2876 int ret = 0; 2877 2878 do { 2879 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) 2880 return 0; 2881 2882 /* matches smp_wmb() in event_sched_in() */ 2883 smp_rmb(); 2884 2885 /* 2886 * We only want to restart ACTIVE events, so if the event goes 2887 * inactive here (event->oncpu==-1), there's nothing more to do; 2888 * fall through with ret==-ENXIO. 2889 */ 2890 ret = cpu_function_call(READ_ONCE(event->oncpu), 2891 __perf_event_stop, &sd); 2892 } while (ret == -EAGAIN); 2893 2894 return ret; 2895 } 2896 2897 /* 2898 * In order to contain the amount of racy and tricky in the address filter 2899 * configuration management, it is a two part process: 2900 * 2901 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below, 2902 * we update the addresses of corresponding vmas in 2903 * event::addr_filter_ranges array and bump the event::addr_filters_gen; 2904 * (p2) when an event is scheduled in (pmu::add), it calls 2905 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync() 2906 * if the generation has changed since the previous call. 2907 * 2908 * If (p1) happens while the event is active, we restart it to force (p2). 2909 * 2910 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on 2911 * pre-existing mappings, called once when new filters arrive via SET_FILTER 2912 * ioctl; 2913 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly 2914 * registered mapping, called for every new mmap(), with mm::mmap_sem down 2915 * for reading; 2916 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process 2917 * of exec. 2918 */ 2919 void perf_event_addr_filters_sync(struct perf_event *event) 2920 { 2921 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 2922 2923 if (!has_addr_filter(event)) 2924 return; 2925 2926 raw_spin_lock(&ifh->lock); 2927 if (event->addr_filters_gen != event->hw.addr_filters_gen) { 2928 event->pmu->addr_filters_sync(event); 2929 event->hw.addr_filters_gen = event->addr_filters_gen; 2930 } 2931 raw_spin_unlock(&ifh->lock); 2932 } 2933 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync); 2934 2935 static int _perf_event_refresh(struct perf_event *event, int refresh) 2936 { 2937 /* 2938 * not supported on inherited events 2939 */ 2940 if (event->attr.inherit || !is_sampling_event(event)) 2941 return -EINVAL; 2942 2943 atomic_add(refresh, &event->event_limit); 2944 _perf_event_enable(event); 2945 2946 return 0; 2947 } 2948 2949 /* 2950 * See perf_event_disable() 2951 */ 2952 int perf_event_refresh(struct perf_event *event, int refresh) 2953 { 2954 struct perf_event_context *ctx; 2955 int ret; 2956 2957 ctx = perf_event_ctx_lock(event); 2958 ret = _perf_event_refresh(event, refresh); 2959 perf_event_ctx_unlock(event, ctx); 2960 2961 return ret; 2962 } 2963 EXPORT_SYMBOL_GPL(perf_event_refresh); 2964 2965 static int perf_event_modify_breakpoint(struct perf_event *bp, 2966 struct perf_event_attr *attr) 2967 { 2968 int err; 2969 2970 _perf_event_disable(bp); 2971 2972 err = modify_user_hw_breakpoint_check(bp, attr, true); 2973 2974 if (!bp->attr.disabled) 2975 _perf_event_enable(bp); 2976 2977 return err; 2978 } 2979 2980 static int perf_event_modify_attr(struct perf_event *event, 2981 struct perf_event_attr *attr) 2982 { 2983 if (event->attr.type != attr->type) 2984 return -EINVAL; 2985 2986 switch (event->attr.type) { 2987 case PERF_TYPE_BREAKPOINT: 2988 return perf_event_modify_breakpoint(event, attr); 2989 default: 2990 /* Place holder for future additions. */ 2991 return -EOPNOTSUPP; 2992 } 2993 } 2994 2995 static void ctx_sched_out(struct perf_event_context *ctx, 2996 struct perf_cpu_context *cpuctx, 2997 enum event_type_t event_type) 2998 { 2999 struct perf_event *event, *tmp; 3000 int is_active = ctx->is_active; 3001 3002 lockdep_assert_held(&ctx->lock); 3003 3004 if (likely(!ctx->nr_events)) { 3005 /* 3006 * See __perf_remove_from_context(). 3007 */ 3008 WARN_ON_ONCE(ctx->is_active); 3009 if (ctx->task) 3010 WARN_ON_ONCE(cpuctx->task_ctx); 3011 return; 3012 } 3013 3014 ctx->is_active &= ~event_type; 3015 if (!(ctx->is_active & EVENT_ALL)) 3016 ctx->is_active = 0; 3017 3018 if (ctx->task) { 3019 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 3020 if (!ctx->is_active) 3021 cpuctx->task_ctx = NULL; 3022 } 3023 3024 /* 3025 * Always update time if it was set; not only when it changes. 3026 * Otherwise we can 'forget' to update time for any but the last 3027 * context we sched out. For example: 3028 * 3029 * ctx_sched_out(.event_type = EVENT_FLEXIBLE) 3030 * ctx_sched_out(.event_type = EVENT_PINNED) 3031 * 3032 * would only update time for the pinned events. 3033 */ 3034 if (is_active & EVENT_TIME) { 3035 /* update (and stop) ctx time */ 3036 update_context_time(ctx); 3037 update_cgrp_time_from_cpuctx(cpuctx); 3038 } 3039 3040 is_active ^= ctx->is_active; /* changed bits */ 3041 3042 if (!ctx->nr_active || !(is_active & EVENT_ALL)) 3043 return; 3044 3045 /* 3046 * If we had been multiplexing, no rotations are necessary, now no events 3047 * are active. 3048 */ 3049 ctx->rotate_necessary = 0; 3050 3051 perf_pmu_disable(ctx->pmu); 3052 if (is_active & EVENT_PINNED) { 3053 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list) 3054 group_sched_out(event, cpuctx, ctx); 3055 } 3056 3057 if (is_active & EVENT_FLEXIBLE) { 3058 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list) 3059 group_sched_out(event, cpuctx, ctx); 3060 } 3061 perf_pmu_enable(ctx->pmu); 3062 } 3063 3064 /* 3065 * Test whether two contexts are equivalent, i.e. whether they have both been 3066 * cloned from the same version of the same context. 3067 * 3068 * Equivalence is measured using a generation number in the context that is 3069 * incremented on each modification to it; see unclone_ctx(), list_add_event() 3070 * and list_del_event(). 3071 */ 3072 static int context_equiv(struct perf_event_context *ctx1, 3073 struct perf_event_context *ctx2) 3074 { 3075 lockdep_assert_held(&ctx1->lock); 3076 lockdep_assert_held(&ctx2->lock); 3077 3078 /* Pinning disables the swap optimization */ 3079 if (ctx1->pin_count || ctx2->pin_count) 3080 return 0; 3081 3082 /* If ctx1 is the parent of ctx2 */ 3083 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen) 3084 return 1; 3085 3086 /* If ctx2 is the parent of ctx1 */ 3087 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation) 3088 return 1; 3089 3090 /* 3091 * If ctx1 and ctx2 have the same parent; we flatten the parent 3092 * hierarchy, see perf_event_init_context(). 3093 */ 3094 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx && 3095 ctx1->parent_gen == ctx2->parent_gen) 3096 return 1; 3097 3098 /* Unmatched */ 3099 return 0; 3100 } 3101 3102 static void __perf_event_sync_stat(struct perf_event *event, 3103 struct perf_event *next_event) 3104 { 3105 u64 value; 3106 3107 if (!event->attr.inherit_stat) 3108 return; 3109 3110 /* 3111 * Update the event value, we cannot use perf_event_read() 3112 * because we're in the middle of a context switch and have IRQs 3113 * disabled, which upsets smp_call_function_single(), however 3114 * we know the event must be on the current CPU, therefore we 3115 * don't need to use it. 3116 */ 3117 if (event->state == PERF_EVENT_STATE_ACTIVE) 3118 event->pmu->read(event); 3119 3120 perf_event_update_time(event); 3121 3122 /* 3123 * In order to keep per-task stats reliable we need to flip the event 3124 * values when we flip the contexts. 3125 */ 3126 value = local64_read(&next_event->count); 3127 value = local64_xchg(&event->count, value); 3128 local64_set(&next_event->count, value); 3129 3130 swap(event->total_time_enabled, next_event->total_time_enabled); 3131 swap(event->total_time_running, next_event->total_time_running); 3132 3133 /* 3134 * Since we swizzled the values, update the user visible data too. 3135 */ 3136 perf_event_update_userpage(event); 3137 perf_event_update_userpage(next_event); 3138 } 3139 3140 static void perf_event_sync_stat(struct perf_event_context *ctx, 3141 struct perf_event_context *next_ctx) 3142 { 3143 struct perf_event *event, *next_event; 3144 3145 if (!ctx->nr_stat) 3146 return; 3147 3148 update_context_time(ctx); 3149 3150 event = list_first_entry(&ctx->event_list, 3151 struct perf_event, event_entry); 3152 3153 next_event = list_first_entry(&next_ctx->event_list, 3154 struct perf_event, event_entry); 3155 3156 while (&event->event_entry != &ctx->event_list && 3157 &next_event->event_entry != &next_ctx->event_list) { 3158 3159 __perf_event_sync_stat(event, next_event); 3160 3161 event = list_next_entry(event, event_entry); 3162 next_event = list_next_entry(next_event, event_entry); 3163 } 3164 } 3165 3166 static void perf_event_context_sched_out(struct task_struct *task, int ctxn, 3167 struct task_struct *next) 3168 { 3169 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn]; 3170 struct perf_event_context *next_ctx; 3171 struct perf_event_context *parent, *next_parent; 3172 struct perf_cpu_context *cpuctx; 3173 int do_switch = 1; 3174 3175 if (likely(!ctx)) 3176 return; 3177 3178 cpuctx = __get_cpu_context(ctx); 3179 if (!cpuctx->task_ctx) 3180 return; 3181 3182 rcu_read_lock(); 3183 next_ctx = next->perf_event_ctxp[ctxn]; 3184 if (!next_ctx) 3185 goto unlock; 3186 3187 parent = rcu_dereference(ctx->parent_ctx); 3188 next_parent = rcu_dereference(next_ctx->parent_ctx); 3189 3190 /* If neither context have a parent context; they cannot be clones. */ 3191 if (!parent && !next_parent) 3192 goto unlock; 3193 3194 if (next_parent == ctx || next_ctx == parent || next_parent == parent) { 3195 /* 3196 * Looks like the two contexts are clones, so we might be 3197 * able to optimize the context switch. We lock both 3198 * contexts and check that they are clones under the 3199 * lock (including re-checking that neither has been 3200 * uncloned in the meantime). It doesn't matter which 3201 * order we take the locks because no other cpu could 3202 * be trying to lock both of these tasks. 3203 */ 3204 raw_spin_lock(&ctx->lock); 3205 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING); 3206 if (context_equiv(ctx, next_ctx)) { 3207 WRITE_ONCE(ctx->task, next); 3208 WRITE_ONCE(next_ctx->task, task); 3209 3210 swap(ctx->task_ctx_data, next_ctx->task_ctx_data); 3211 3212 /* 3213 * RCU_INIT_POINTER here is safe because we've not 3214 * modified the ctx and the above modification of 3215 * ctx->task and ctx->task_ctx_data are immaterial 3216 * since those values are always verified under 3217 * ctx->lock which we're now holding. 3218 */ 3219 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx); 3220 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx); 3221 3222 do_switch = 0; 3223 3224 perf_event_sync_stat(ctx, next_ctx); 3225 } 3226 raw_spin_unlock(&next_ctx->lock); 3227 raw_spin_unlock(&ctx->lock); 3228 } 3229 unlock: 3230 rcu_read_unlock(); 3231 3232 if (do_switch) { 3233 raw_spin_lock(&ctx->lock); 3234 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL); 3235 raw_spin_unlock(&ctx->lock); 3236 } 3237 } 3238 3239 static DEFINE_PER_CPU(struct list_head, sched_cb_list); 3240 3241 void perf_sched_cb_dec(struct pmu *pmu) 3242 { 3243 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 3244 3245 this_cpu_dec(perf_sched_cb_usages); 3246 3247 if (!--cpuctx->sched_cb_usage) 3248 list_del(&cpuctx->sched_cb_entry); 3249 } 3250 3251 3252 void perf_sched_cb_inc(struct pmu *pmu) 3253 { 3254 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 3255 3256 if (!cpuctx->sched_cb_usage++) 3257 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list)); 3258 3259 this_cpu_inc(perf_sched_cb_usages); 3260 } 3261 3262 /* 3263 * This function provides the context switch callback to the lower code 3264 * layer. It is invoked ONLY when the context switch callback is enabled. 3265 * 3266 * This callback is relevant even to per-cpu events; for example multi event 3267 * PEBS requires this to provide PID/TID information. This requires we flush 3268 * all queued PEBS records before we context switch to a new task. 3269 */ 3270 static void perf_pmu_sched_task(struct task_struct *prev, 3271 struct task_struct *next, 3272 bool sched_in) 3273 { 3274 struct perf_cpu_context *cpuctx; 3275 struct pmu *pmu; 3276 3277 if (prev == next) 3278 return; 3279 3280 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) { 3281 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */ 3282 3283 if (WARN_ON_ONCE(!pmu->sched_task)) 3284 continue; 3285 3286 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 3287 perf_pmu_disable(pmu); 3288 3289 pmu->sched_task(cpuctx->task_ctx, sched_in); 3290 3291 perf_pmu_enable(pmu); 3292 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 3293 } 3294 } 3295 3296 static void perf_event_switch(struct task_struct *task, 3297 struct task_struct *next_prev, bool sched_in); 3298 3299 #define for_each_task_context_nr(ctxn) \ 3300 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++) 3301 3302 /* 3303 * Called from scheduler to remove the events of the current task, 3304 * with interrupts disabled. 3305 * 3306 * We stop each event and update the event value in event->count. 3307 * 3308 * This does not protect us against NMI, but disable() 3309 * sets the disabled bit in the control field of event _before_ 3310 * accessing the event control register. If a NMI hits, then it will 3311 * not restart the event. 3312 */ 3313 void __perf_event_task_sched_out(struct task_struct *task, 3314 struct task_struct *next) 3315 { 3316 int ctxn; 3317 3318 if (__this_cpu_read(perf_sched_cb_usages)) 3319 perf_pmu_sched_task(task, next, false); 3320 3321 if (atomic_read(&nr_switch_events)) 3322 perf_event_switch(task, next, false); 3323 3324 for_each_task_context_nr(ctxn) 3325 perf_event_context_sched_out(task, ctxn, next); 3326 3327 /* 3328 * if cgroup events exist on this CPU, then we need 3329 * to check if we have to switch out PMU state. 3330 * cgroup event are system-wide mode only 3331 */ 3332 if (atomic_read(this_cpu_ptr(&perf_cgroup_events))) 3333 perf_cgroup_sched_out(task, next); 3334 } 3335 3336 /* 3337 * Called with IRQs disabled 3338 */ 3339 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, 3340 enum event_type_t event_type) 3341 { 3342 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type); 3343 } 3344 3345 static int visit_groups_merge(struct perf_event_groups *groups, int cpu, 3346 int (*func)(struct perf_event *, void *), void *data) 3347 { 3348 struct perf_event **evt, *evt1, *evt2; 3349 int ret; 3350 3351 evt1 = perf_event_groups_first(groups, -1); 3352 evt2 = perf_event_groups_first(groups, cpu); 3353 3354 while (evt1 || evt2) { 3355 if (evt1 && evt2) { 3356 if (evt1->group_index < evt2->group_index) 3357 evt = &evt1; 3358 else 3359 evt = &evt2; 3360 } else if (evt1) { 3361 evt = &evt1; 3362 } else { 3363 evt = &evt2; 3364 } 3365 3366 ret = func(*evt, data); 3367 if (ret) 3368 return ret; 3369 3370 *evt = perf_event_groups_next(*evt); 3371 } 3372 3373 return 0; 3374 } 3375 3376 struct sched_in_data { 3377 struct perf_event_context *ctx; 3378 struct perf_cpu_context *cpuctx; 3379 int can_add_hw; 3380 }; 3381 3382 static int pinned_sched_in(struct perf_event *event, void *data) 3383 { 3384 struct sched_in_data *sid = data; 3385 3386 if (event->state <= PERF_EVENT_STATE_OFF) 3387 return 0; 3388 3389 if (!event_filter_match(event)) 3390 return 0; 3391 3392 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) { 3393 if (!group_sched_in(event, sid->cpuctx, sid->ctx)) 3394 list_add_tail(&event->active_list, &sid->ctx->pinned_active); 3395 } 3396 3397 /* 3398 * If this pinned group hasn't been scheduled, 3399 * put it in error state. 3400 */ 3401 if (event->state == PERF_EVENT_STATE_INACTIVE) 3402 perf_event_set_state(event, PERF_EVENT_STATE_ERROR); 3403 3404 return 0; 3405 } 3406 3407 static int flexible_sched_in(struct perf_event *event, void *data) 3408 { 3409 struct sched_in_data *sid = data; 3410 3411 if (event->state <= PERF_EVENT_STATE_OFF) 3412 return 0; 3413 3414 if (!event_filter_match(event)) 3415 return 0; 3416 3417 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) { 3418 int ret = group_sched_in(event, sid->cpuctx, sid->ctx); 3419 if (ret) { 3420 sid->can_add_hw = 0; 3421 sid->ctx->rotate_necessary = 1; 3422 return 0; 3423 } 3424 list_add_tail(&event->active_list, &sid->ctx->flexible_active); 3425 } 3426 3427 return 0; 3428 } 3429 3430 static void 3431 ctx_pinned_sched_in(struct perf_event_context *ctx, 3432 struct perf_cpu_context *cpuctx) 3433 { 3434 struct sched_in_data sid = { 3435 .ctx = ctx, 3436 .cpuctx = cpuctx, 3437 .can_add_hw = 1, 3438 }; 3439 3440 visit_groups_merge(&ctx->pinned_groups, 3441 smp_processor_id(), 3442 pinned_sched_in, &sid); 3443 } 3444 3445 static void 3446 ctx_flexible_sched_in(struct perf_event_context *ctx, 3447 struct perf_cpu_context *cpuctx) 3448 { 3449 struct sched_in_data sid = { 3450 .ctx = ctx, 3451 .cpuctx = cpuctx, 3452 .can_add_hw = 1, 3453 }; 3454 3455 visit_groups_merge(&ctx->flexible_groups, 3456 smp_processor_id(), 3457 flexible_sched_in, &sid); 3458 } 3459 3460 static void 3461 ctx_sched_in(struct perf_event_context *ctx, 3462 struct perf_cpu_context *cpuctx, 3463 enum event_type_t event_type, 3464 struct task_struct *task) 3465 { 3466 int is_active = ctx->is_active; 3467 u64 now; 3468 3469 lockdep_assert_held(&ctx->lock); 3470 3471 if (likely(!ctx->nr_events)) 3472 return; 3473 3474 ctx->is_active |= (event_type | EVENT_TIME); 3475 if (ctx->task) { 3476 if (!is_active) 3477 cpuctx->task_ctx = ctx; 3478 else 3479 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 3480 } 3481 3482 is_active ^= ctx->is_active; /* changed bits */ 3483 3484 if (is_active & EVENT_TIME) { 3485 /* start ctx time */ 3486 now = perf_clock(); 3487 ctx->timestamp = now; 3488 perf_cgroup_set_timestamp(task, ctx); 3489 } 3490 3491 /* 3492 * First go through the list and put on any pinned groups 3493 * in order to give them the best chance of going on. 3494 */ 3495 if (is_active & EVENT_PINNED) 3496 ctx_pinned_sched_in(ctx, cpuctx); 3497 3498 /* Then walk through the lower prio flexible groups */ 3499 if (is_active & EVENT_FLEXIBLE) 3500 ctx_flexible_sched_in(ctx, cpuctx); 3501 } 3502 3503 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, 3504 enum event_type_t event_type, 3505 struct task_struct *task) 3506 { 3507 struct perf_event_context *ctx = &cpuctx->ctx; 3508 3509 ctx_sched_in(ctx, cpuctx, event_type, task); 3510 } 3511 3512 static void perf_event_context_sched_in(struct perf_event_context *ctx, 3513 struct task_struct *task) 3514 { 3515 struct perf_cpu_context *cpuctx; 3516 3517 cpuctx = __get_cpu_context(ctx); 3518 if (cpuctx->task_ctx == ctx) 3519 return; 3520 3521 perf_ctx_lock(cpuctx, ctx); 3522 /* 3523 * We must check ctx->nr_events while holding ctx->lock, such 3524 * that we serialize against perf_install_in_context(). 3525 */ 3526 if (!ctx->nr_events) 3527 goto unlock; 3528 3529 perf_pmu_disable(ctx->pmu); 3530 /* 3531 * We want to keep the following priority order: 3532 * cpu pinned (that don't need to move), task pinned, 3533 * cpu flexible, task flexible. 3534 * 3535 * However, if task's ctx is not carrying any pinned 3536 * events, no need to flip the cpuctx's events around. 3537 */ 3538 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree)) 3539 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); 3540 perf_event_sched_in(cpuctx, ctx, task); 3541 perf_pmu_enable(ctx->pmu); 3542 3543 unlock: 3544 perf_ctx_unlock(cpuctx, ctx); 3545 } 3546 3547 /* 3548 * Called from scheduler to add the events of the current task 3549 * with interrupts disabled. 3550 * 3551 * We restore the event value and then enable it. 3552 * 3553 * This does not protect us against NMI, but enable() 3554 * sets the enabled bit in the control field of event _before_ 3555 * accessing the event control register. If a NMI hits, then it will 3556 * keep the event running. 3557 */ 3558 void __perf_event_task_sched_in(struct task_struct *prev, 3559 struct task_struct *task) 3560 { 3561 struct perf_event_context *ctx; 3562 int ctxn; 3563 3564 /* 3565 * If cgroup events exist on this CPU, then we need to check if we have 3566 * to switch in PMU state; cgroup event are system-wide mode only. 3567 * 3568 * Since cgroup events are CPU events, we must schedule these in before 3569 * we schedule in the task events. 3570 */ 3571 if (atomic_read(this_cpu_ptr(&perf_cgroup_events))) 3572 perf_cgroup_sched_in(prev, task); 3573 3574 for_each_task_context_nr(ctxn) { 3575 ctx = task->perf_event_ctxp[ctxn]; 3576 if (likely(!ctx)) 3577 continue; 3578 3579 perf_event_context_sched_in(ctx, task); 3580 } 3581 3582 if (atomic_read(&nr_switch_events)) 3583 perf_event_switch(task, prev, true); 3584 3585 if (__this_cpu_read(perf_sched_cb_usages)) 3586 perf_pmu_sched_task(prev, task, true); 3587 } 3588 3589 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count) 3590 { 3591 u64 frequency = event->attr.sample_freq; 3592 u64 sec = NSEC_PER_SEC; 3593 u64 divisor, dividend; 3594 3595 int count_fls, nsec_fls, frequency_fls, sec_fls; 3596 3597 count_fls = fls64(count); 3598 nsec_fls = fls64(nsec); 3599 frequency_fls = fls64(frequency); 3600 sec_fls = 30; 3601 3602 /* 3603 * We got @count in @nsec, with a target of sample_freq HZ 3604 * the target period becomes: 3605 * 3606 * @count * 10^9 3607 * period = ------------------- 3608 * @nsec * sample_freq 3609 * 3610 */ 3611 3612 /* 3613 * Reduce accuracy by one bit such that @a and @b converge 3614 * to a similar magnitude. 3615 */ 3616 #define REDUCE_FLS(a, b) \ 3617 do { \ 3618 if (a##_fls > b##_fls) { \ 3619 a >>= 1; \ 3620 a##_fls--; \ 3621 } else { \ 3622 b >>= 1; \ 3623 b##_fls--; \ 3624 } \ 3625 } while (0) 3626 3627 /* 3628 * Reduce accuracy until either term fits in a u64, then proceed with 3629 * the other, so that finally we can do a u64/u64 division. 3630 */ 3631 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) { 3632 REDUCE_FLS(nsec, frequency); 3633 REDUCE_FLS(sec, count); 3634 } 3635 3636 if (count_fls + sec_fls > 64) { 3637 divisor = nsec * frequency; 3638 3639 while (count_fls + sec_fls > 64) { 3640 REDUCE_FLS(count, sec); 3641 divisor >>= 1; 3642 } 3643 3644 dividend = count * sec; 3645 } else { 3646 dividend = count * sec; 3647 3648 while (nsec_fls + frequency_fls > 64) { 3649 REDUCE_FLS(nsec, frequency); 3650 dividend >>= 1; 3651 } 3652 3653 divisor = nsec * frequency; 3654 } 3655 3656 if (!divisor) 3657 return dividend; 3658 3659 return div64_u64(dividend, divisor); 3660 } 3661 3662 static DEFINE_PER_CPU(int, perf_throttled_count); 3663 static DEFINE_PER_CPU(u64, perf_throttled_seq); 3664 3665 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable) 3666 { 3667 struct hw_perf_event *hwc = &event->hw; 3668 s64 period, sample_period; 3669 s64 delta; 3670 3671 period = perf_calculate_period(event, nsec, count); 3672 3673 delta = (s64)(period - hwc->sample_period); 3674 delta = (delta + 7) / 8; /* low pass filter */ 3675 3676 sample_period = hwc->sample_period + delta; 3677 3678 if (!sample_period) 3679 sample_period = 1; 3680 3681 hwc->sample_period = sample_period; 3682 3683 if (local64_read(&hwc->period_left) > 8*sample_period) { 3684 if (disable) 3685 event->pmu->stop(event, PERF_EF_UPDATE); 3686 3687 local64_set(&hwc->period_left, 0); 3688 3689 if (disable) 3690 event->pmu->start(event, PERF_EF_RELOAD); 3691 } 3692 } 3693 3694 /* 3695 * combine freq adjustment with unthrottling to avoid two passes over the 3696 * events. At the same time, make sure, having freq events does not change 3697 * the rate of unthrottling as that would introduce bias. 3698 */ 3699 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx, 3700 int needs_unthr) 3701 { 3702 struct perf_event *event; 3703 struct hw_perf_event *hwc; 3704 u64 now, period = TICK_NSEC; 3705 s64 delta; 3706 3707 /* 3708 * only need to iterate over all events iff: 3709 * - context have events in frequency mode (needs freq adjust) 3710 * - there are events to unthrottle on this cpu 3711 */ 3712 if (!(ctx->nr_freq || needs_unthr)) 3713 return; 3714 3715 raw_spin_lock(&ctx->lock); 3716 perf_pmu_disable(ctx->pmu); 3717 3718 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 3719 if (event->state != PERF_EVENT_STATE_ACTIVE) 3720 continue; 3721 3722 if (!event_filter_match(event)) 3723 continue; 3724 3725 perf_pmu_disable(event->pmu); 3726 3727 hwc = &event->hw; 3728 3729 if (hwc->interrupts == MAX_INTERRUPTS) { 3730 hwc->interrupts = 0; 3731 perf_log_throttle(event, 1); 3732 event->pmu->start(event, 0); 3733 } 3734 3735 if (!event->attr.freq || !event->attr.sample_freq) 3736 goto next; 3737 3738 /* 3739 * stop the event and update event->count 3740 */ 3741 event->pmu->stop(event, PERF_EF_UPDATE); 3742 3743 now = local64_read(&event->count); 3744 delta = now - hwc->freq_count_stamp; 3745 hwc->freq_count_stamp = now; 3746 3747 /* 3748 * restart the event 3749 * reload only if value has changed 3750 * we have stopped the event so tell that 3751 * to perf_adjust_period() to avoid stopping it 3752 * twice. 3753 */ 3754 if (delta > 0) 3755 perf_adjust_period(event, period, delta, false); 3756 3757 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0); 3758 next: 3759 perf_pmu_enable(event->pmu); 3760 } 3761 3762 perf_pmu_enable(ctx->pmu); 3763 raw_spin_unlock(&ctx->lock); 3764 } 3765 3766 /* 3767 * Move @event to the tail of the @ctx's elegible events. 3768 */ 3769 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event) 3770 { 3771 /* 3772 * Rotate the first entry last of non-pinned groups. Rotation might be 3773 * disabled by the inheritance code. 3774 */ 3775 if (ctx->rotate_disable) 3776 return; 3777 3778 perf_event_groups_delete(&ctx->flexible_groups, event); 3779 perf_event_groups_insert(&ctx->flexible_groups, event); 3780 } 3781 3782 /* pick an event from the flexible_groups to rotate */ 3783 static inline struct perf_event * 3784 ctx_event_to_rotate(struct perf_event_context *ctx) 3785 { 3786 struct perf_event *event; 3787 3788 /* pick the first active flexible event */ 3789 event = list_first_entry_or_null(&ctx->flexible_active, 3790 struct perf_event, active_list); 3791 3792 /* if no active flexible event, pick the first event */ 3793 if (!event) { 3794 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree), 3795 typeof(*event), group_node); 3796 } 3797 3798 return event; 3799 } 3800 3801 static bool perf_rotate_context(struct perf_cpu_context *cpuctx) 3802 { 3803 struct perf_event *cpu_event = NULL, *task_event = NULL; 3804 struct perf_event_context *task_ctx = NULL; 3805 int cpu_rotate, task_rotate; 3806 3807 /* 3808 * Since we run this from IRQ context, nobody can install new 3809 * events, thus the event count values are stable. 3810 */ 3811 3812 cpu_rotate = cpuctx->ctx.rotate_necessary; 3813 task_ctx = cpuctx->task_ctx; 3814 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0; 3815 3816 if (!(cpu_rotate || task_rotate)) 3817 return false; 3818 3819 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 3820 perf_pmu_disable(cpuctx->ctx.pmu); 3821 3822 if (task_rotate) 3823 task_event = ctx_event_to_rotate(task_ctx); 3824 if (cpu_rotate) 3825 cpu_event = ctx_event_to_rotate(&cpuctx->ctx); 3826 3827 /* 3828 * As per the order given at ctx_resched() first 'pop' task flexible 3829 * and then, if needed CPU flexible. 3830 */ 3831 if (task_event || (task_ctx && cpu_event)) 3832 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE); 3833 if (cpu_event) 3834 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); 3835 3836 if (task_event) 3837 rotate_ctx(task_ctx, task_event); 3838 if (cpu_event) 3839 rotate_ctx(&cpuctx->ctx, cpu_event); 3840 3841 perf_event_sched_in(cpuctx, task_ctx, current); 3842 3843 perf_pmu_enable(cpuctx->ctx.pmu); 3844 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 3845 3846 return true; 3847 } 3848 3849 void perf_event_task_tick(void) 3850 { 3851 struct list_head *head = this_cpu_ptr(&active_ctx_list); 3852 struct perf_event_context *ctx, *tmp; 3853 int throttled; 3854 3855 lockdep_assert_irqs_disabled(); 3856 3857 __this_cpu_inc(perf_throttled_seq); 3858 throttled = __this_cpu_xchg(perf_throttled_count, 0); 3859 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); 3860 3861 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list) 3862 perf_adjust_freq_unthr_context(ctx, throttled); 3863 } 3864 3865 static int event_enable_on_exec(struct perf_event *event, 3866 struct perf_event_context *ctx) 3867 { 3868 if (!event->attr.enable_on_exec) 3869 return 0; 3870 3871 event->attr.enable_on_exec = 0; 3872 if (event->state >= PERF_EVENT_STATE_INACTIVE) 3873 return 0; 3874 3875 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE); 3876 3877 return 1; 3878 } 3879 3880 /* 3881 * Enable all of a task's events that have been marked enable-on-exec. 3882 * This expects task == current. 3883 */ 3884 static void perf_event_enable_on_exec(int ctxn) 3885 { 3886 struct perf_event_context *ctx, *clone_ctx = NULL; 3887 enum event_type_t event_type = 0; 3888 struct perf_cpu_context *cpuctx; 3889 struct perf_event *event; 3890 unsigned long flags; 3891 int enabled = 0; 3892 3893 local_irq_save(flags); 3894 ctx = current->perf_event_ctxp[ctxn]; 3895 if (!ctx || !ctx->nr_events) 3896 goto out; 3897 3898 cpuctx = __get_cpu_context(ctx); 3899 perf_ctx_lock(cpuctx, ctx); 3900 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 3901 list_for_each_entry(event, &ctx->event_list, event_entry) { 3902 enabled |= event_enable_on_exec(event, ctx); 3903 event_type |= get_event_type(event); 3904 } 3905 3906 /* 3907 * Unclone and reschedule this context if we enabled any event. 3908 */ 3909 if (enabled) { 3910 clone_ctx = unclone_ctx(ctx); 3911 ctx_resched(cpuctx, ctx, event_type); 3912 } else { 3913 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current); 3914 } 3915 perf_ctx_unlock(cpuctx, ctx); 3916 3917 out: 3918 local_irq_restore(flags); 3919 3920 if (clone_ctx) 3921 put_ctx(clone_ctx); 3922 } 3923 3924 struct perf_read_data { 3925 struct perf_event *event; 3926 bool group; 3927 int ret; 3928 }; 3929 3930 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu) 3931 { 3932 u16 local_pkg, event_pkg; 3933 3934 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) { 3935 int local_cpu = smp_processor_id(); 3936 3937 event_pkg = topology_physical_package_id(event_cpu); 3938 local_pkg = topology_physical_package_id(local_cpu); 3939 3940 if (event_pkg == local_pkg) 3941 return local_cpu; 3942 } 3943 3944 return event_cpu; 3945 } 3946 3947 /* 3948 * Cross CPU call to read the hardware event 3949 */ 3950 static void __perf_event_read(void *info) 3951 { 3952 struct perf_read_data *data = info; 3953 struct perf_event *sub, *event = data->event; 3954 struct perf_event_context *ctx = event->ctx; 3955 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 3956 struct pmu *pmu = event->pmu; 3957 3958 /* 3959 * If this is a task context, we need to check whether it is 3960 * the current task context of this cpu. If not it has been 3961 * scheduled out before the smp call arrived. In that case 3962 * event->count would have been updated to a recent sample 3963 * when the event was scheduled out. 3964 */ 3965 if (ctx->task && cpuctx->task_ctx != ctx) 3966 return; 3967 3968 raw_spin_lock(&ctx->lock); 3969 if (ctx->is_active & EVENT_TIME) { 3970 update_context_time(ctx); 3971 update_cgrp_time_from_event(event); 3972 } 3973 3974 perf_event_update_time(event); 3975 if (data->group) 3976 perf_event_update_sibling_time(event); 3977 3978 if (event->state != PERF_EVENT_STATE_ACTIVE) 3979 goto unlock; 3980 3981 if (!data->group) { 3982 pmu->read(event); 3983 data->ret = 0; 3984 goto unlock; 3985 } 3986 3987 pmu->start_txn(pmu, PERF_PMU_TXN_READ); 3988 3989 pmu->read(event); 3990 3991 for_each_sibling_event(sub, event) { 3992 if (sub->state == PERF_EVENT_STATE_ACTIVE) { 3993 /* 3994 * Use sibling's PMU rather than @event's since 3995 * sibling could be on different (eg: software) PMU. 3996 */ 3997 sub->pmu->read(sub); 3998 } 3999 } 4000 4001 data->ret = pmu->commit_txn(pmu); 4002 4003 unlock: 4004 raw_spin_unlock(&ctx->lock); 4005 } 4006 4007 static inline u64 perf_event_count(struct perf_event *event) 4008 { 4009 return local64_read(&event->count) + atomic64_read(&event->child_count); 4010 } 4011 4012 /* 4013 * NMI-safe method to read a local event, that is an event that 4014 * is: 4015 * - either for the current task, or for this CPU 4016 * - does not have inherit set, for inherited task events 4017 * will not be local and we cannot read them atomically 4018 * - must not have a pmu::count method 4019 */ 4020 int perf_event_read_local(struct perf_event *event, u64 *value, 4021 u64 *enabled, u64 *running) 4022 { 4023 unsigned long flags; 4024 int ret = 0; 4025 4026 /* 4027 * Disabling interrupts avoids all counter scheduling (context 4028 * switches, timer based rotation and IPIs). 4029 */ 4030 local_irq_save(flags); 4031 4032 /* 4033 * It must not be an event with inherit set, we cannot read 4034 * all child counters from atomic context. 4035 */ 4036 if (event->attr.inherit) { 4037 ret = -EOPNOTSUPP; 4038 goto out; 4039 } 4040 4041 /* If this is a per-task event, it must be for current */ 4042 if ((event->attach_state & PERF_ATTACH_TASK) && 4043 event->hw.target != current) { 4044 ret = -EINVAL; 4045 goto out; 4046 } 4047 4048 /* If this is a per-CPU event, it must be for this CPU */ 4049 if (!(event->attach_state & PERF_ATTACH_TASK) && 4050 event->cpu != smp_processor_id()) { 4051 ret = -EINVAL; 4052 goto out; 4053 } 4054 4055 /* If this is a pinned event it must be running on this CPU */ 4056 if (event->attr.pinned && event->oncpu != smp_processor_id()) { 4057 ret = -EBUSY; 4058 goto out; 4059 } 4060 4061 /* 4062 * If the event is currently on this CPU, its either a per-task event, 4063 * or local to this CPU. Furthermore it means its ACTIVE (otherwise 4064 * oncpu == -1). 4065 */ 4066 if (event->oncpu == smp_processor_id()) 4067 event->pmu->read(event); 4068 4069 *value = local64_read(&event->count); 4070 if (enabled || running) { 4071 u64 now = event->shadow_ctx_time + perf_clock(); 4072 u64 __enabled, __running; 4073 4074 __perf_update_times(event, now, &__enabled, &__running); 4075 if (enabled) 4076 *enabled = __enabled; 4077 if (running) 4078 *running = __running; 4079 } 4080 out: 4081 local_irq_restore(flags); 4082 4083 return ret; 4084 } 4085 4086 static int perf_event_read(struct perf_event *event, bool group) 4087 { 4088 enum perf_event_state state = READ_ONCE(event->state); 4089 int event_cpu, ret = 0; 4090 4091 /* 4092 * If event is enabled and currently active on a CPU, update the 4093 * value in the event structure: 4094 */ 4095 again: 4096 if (state == PERF_EVENT_STATE_ACTIVE) { 4097 struct perf_read_data data; 4098 4099 /* 4100 * Orders the ->state and ->oncpu loads such that if we see 4101 * ACTIVE we must also see the right ->oncpu. 4102 * 4103 * Matches the smp_wmb() from event_sched_in(). 4104 */ 4105 smp_rmb(); 4106 4107 event_cpu = READ_ONCE(event->oncpu); 4108 if ((unsigned)event_cpu >= nr_cpu_ids) 4109 return 0; 4110 4111 data = (struct perf_read_data){ 4112 .event = event, 4113 .group = group, 4114 .ret = 0, 4115 }; 4116 4117 preempt_disable(); 4118 event_cpu = __perf_event_read_cpu(event, event_cpu); 4119 4120 /* 4121 * Purposely ignore the smp_call_function_single() return 4122 * value. 4123 * 4124 * If event_cpu isn't a valid CPU it means the event got 4125 * scheduled out and that will have updated the event count. 4126 * 4127 * Therefore, either way, we'll have an up-to-date event count 4128 * after this. 4129 */ 4130 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1); 4131 preempt_enable(); 4132 ret = data.ret; 4133 4134 } else if (state == PERF_EVENT_STATE_INACTIVE) { 4135 struct perf_event_context *ctx = event->ctx; 4136 unsigned long flags; 4137 4138 raw_spin_lock_irqsave(&ctx->lock, flags); 4139 state = event->state; 4140 if (state != PERF_EVENT_STATE_INACTIVE) { 4141 raw_spin_unlock_irqrestore(&ctx->lock, flags); 4142 goto again; 4143 } 4144 4145 /* 4146 * May read while context is not active (e.g., thread is 4147 * blocked), in that case we cannot update context time 4148 */ 4149 if (ctx->is_active & EVENT_TIME) { 4150 update_context_time(ctx); 4151 update_cgrp_time_from_event(event); 4152 } 4153 4154 perf_event_update_time(event); 4155 if (group) 4156 perf_event_update_sibling_time(event); 4157 raw_spin_unlock_irqrestore(&ctx->lock, flags); 4158 } 4159 4160 return ret; 4161 } 4162 4163 /* 4164 * Initialize the perf_event context in a task_struct: 4165 */ 4166 static void __perf_event_init_context(struct perf_event_context *ctx) 4167 { 4168 raw_spin_lock_init(&ctx->lock); 4169 mutex_init(&ctx->mutex); 4170 INIT_LIST_HEAD(&ctx->active_ctx_list); 4171 perf_event_groups_init(&ctx->pinned_groups); 4172 perf_event_groups_init(&ctx->flexible_groups); 4173 INIT_LIST_HEAD(&ctx->event_list); 4174 INIT_LIST_HEAD(&ctx->pinned_active); 4175 INIT_LIST_HEAD(&ctx->flexible_active); 4176 refcount_set(&ctx->refcount, 1); 4177 } 4178 4179 static struct perf_event_context * 4180 alloc_perf_context(struct pmu *pmu, struct task_struct *task) 4181 { 4182 struct perf_event_context *ctx; 4183 4184 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL); 4185 if (!ctx) 4186 return NULL; 4187 4188 __perf_event_init_context(ctx); 4189 if (task) 4190 ctx->task = get_task_struct(task); 4191 ctx->pmu = pmu; 4192 4193 return ctx; 4194 } 4195 4196 static struct task_struct * 4197 find_lively_task_by_vpid(pid_t vpid) 4198 { 4199 struct task_struct *task; 4200 4201 rcu_read_lock(); 4202 if (!vpid) 4203 task = current; 4204 else 4205 task = find_task_by_vpid(vpid); 4206 if (task) 4207 get_task_struct(task); 4208 rcu_read_unlock(); 4209 4210 if (!task) 4211 return ERR_PTR(-ESRCH); 4212 4213 return task; 4214 } 4215 4216 /* 4217 * Returns a matching context with refcount and pincount. 4218 */ 4219 static struct perf_event_context * 4220 find_get_context(struct pmu *pmu, struct task_struct *task, 4221 struct perf_event *event) 4222 { 4223 struct perf_event_context *ctx, *clone_ctx = NULL; 4224 struct perf_cpu_context *cpuctx; 4225 void *task_ctx_data = NULL; 4226 unsigned long flags; 4227 int ctxn, err; 4228 int cpu = event->cpu; 4229 4230 if (!task) { 4231 /* Must be root to operate on a CPU event: */ 4232 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN)) 4233 return ERR_PTR(-EACCES); 4234 4235 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 4236 ctx = &cpuctx->ctx; 4237 get_ctx(ctx); 4238 ++ctx->pin_count; 4239 4240 return ctx; 4241 } 4242 4243 err = -EINVAL; 4244 ctxn = pmu->task_ctx_nr; 4245 if (ctxn < 0) 4246 goto errout; 4247 4248 if (event->attach_state & PERF_ATTACH_TASK_DATA) { 4249 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL); 4250 if (!task_ctx_data) { 4251 err = -ENOMEM; 4252 goto errout; 4253 } 4254 } 4255 4256 retry: 4257 ctx = perf_lock_task_context(task, ctxn, &flags); 4258 if (ctx) { 4259 clone_ctx = unclone_ctx(ctx); 4260 ++ctx->pin_count; 4261 4262 if (task_ctx_data && !ctx->task_ctx_data) { 4263 ctx->task_ctx_data = task_ctx_data; 4264 task_ctx_data = NULL; 4265 } 4266 raw_spin_unlock_irqrestore(&ctx->lock, flags); 4267 4268 if (clone_ctx) 4269 put_ctx(clone_ctx); 4270 } else { 4271 ctx = alloc_perf_context(pmu, task); 4272 err = -ENOMEM; 4273 if (!ctx) 4274 goto errout; 4275 4276 if (task_ctx_data) { 4277 ctx->task_ctx_data = task_ctx_data; 4278 task_ctx_data = NULL; 4279 } 4280 4281 err = 0; 4282 mutex_lock(&task->perf_event_mutex); 4283 /* 4284 * If it has already passed perf_event_exit_task(). 4285 * we must see PF_EXITING, it takes this mutex too. 4286 */ 4287 if (task->flags & PF_EXITING) 4288 err = -ESRCH; 4289 else if (task->perf_event_ctxp[ctxn]) 4290 err = -EAGAIN; 4291 else { 4292 get_ctx(ctx); 4293 ++ctx->pin_count; 4294 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx); 4295 } 4296 mutex_unlock(&task->perf_event_mutex); 4297 4298 if (unlikely(err)) { 4299 put_ctx(ctx); 4300 4301 if (err == -EAGAIN) 4302 goto retry; 4303 goto errout; 4304 } 4305 } 4306 4307 kfree(task_ctx_data); 4308 return ctx; 4309 4310 errout: 4311 kfree(task_ctx_data); 4312 return ERR_PTR(err); 4313 } 4314 4315 static void perf_event_free_filter(struct perf_event *event); 4316 static void perf_event_free_bpf_prog(struct perf_event *event); 4317 4318 static void free_event_rcu(struct rcu_head *head) 4319 { 4320 struct perf_event *event; 4321 4322 event = container_of(head, struct perf_event, rcu_head); 4323 if (event->ns) 4324 put_pid_ns(event->ns); 4325 perf_event_free_filter(event); 4326 kfree(event); 4327 } 4328 4329 static void ring_buffer_attach(struct perf_event *event, 4330 struct ring_buffer *rb); 4331 4332 static void detach_sb_event(struct perf_event *event) 4333 { 4334 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu); 4335 4336 raw_spin_lock(&pel->lock); 4337 list_del_rcu(&event->sb_list); 4338 raw_spin_unlock(&pel->lock); 4339 } 4340 4341 static bool is_sb_event(struct perf_event *event) 4342 { 4343 struct perf_event_attr *attr = &event->attr; 4344 4345 if (event->parent) 4346 return false; 4347 4348 if (event->attach_state & PERF_ATTACH_TASK) 4349 return false; 4350 4351 if (attr->mmap || attr->mmap_data || attr->mmap2 || 4352 attr->comm || attr->comm_exec || 4353 attr->task || attr->ksymbol || 4354 attr->context_switch || 4355 attr->bpf_event) 4356 return true; 4357 return false; 4358 } 4359 4360 static void unaccount_pmu_sb_event(struct perf_event *event) 4361 { 4362 if (is_sb_event(event)) 4363 detach_sb_event(event); 4364 } 4365 4366 static void unaccount_event_cpu(struct perf_event *event, int cpu) 4367 { 4368 if (event->parent) 4369 return; 4370 4371 if (is_cgroup_event(event)) 4372 atomic_dec(&per_cpu(perf_cgroup_events, cpu)); 4373 } 4374 4375 #ifdef CONFIG_NO_HZ_FULL 4376 static DEFINE_SPINLOCK(nr_freq_lock); 4377 #endif 4378 4379 static void unaccount_freq_event_nohz(void) 4380 { 4381 #ifdef CONFIG_NO_HZ_FULL 4382 spin_lock(&nr_freq_lock); 4383 if (atomic_dec_and_test(&nr_freq_events)) 4384 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS); 4385 spin_unlock(&nr_freq_lock); 4386 #endif 4387 } 4388 4389 static void unaccount_freq_event(void) 4390 { 4391 if (tick_nohz_full_enabled()) 4392 unaccount_freq_event_nohz(); 4393 else 4394 atomic_dec(&nr_freq_events); 4395 } 4396 4397 static void unaccount_event(struct perf_event *event) 4398 { 4399 bool dec = false; 4400 4401 if (event->parent) 4402 return; 4403 4404 if (event->attach_state & PERF_ATTACH_TASK) 4405 dec = true; 4406 if (event->attr.mmap || event->attr.mmap_data) 4407 atomic_dec(&nr_mmap_events); 4408 if (event->attr.comm) 4409 atomic_dec(&nr_comm_events); 4410 if (event->attr.namespaces) 4411 atomic_dec(&nr_namespaces_events); 4412 if (event->attr.task) 4413 atomic_dec(&nr_task_events); 4414 if (event->attr.freq) 4415 unaccount_freq_event(); 4416 if (event->attr.context_switch) { 4417 dec = true; 4418 atomic_dec(&nr_switch_events); 4419 } 4420 if (is_cgroup_event(event)) 4421 dec = true; 4422 if (has_branch_stack(event)) 4423 dec = true; 4424 if (event->attr.ksymbol) 4425 atomic_dec(&nr_ksymbol_events); 4426 if (event->attr.bpf_event) 4427 atomic_dec(&nr_bpf_events); 4428 4429 if (dec) { 4430 if (!atomic_add_unless(&perf_sched_count, -1, 1)) 4431 schedule_delayed_work(&perf_sched_work, HZ); 4432 } 4433 4434 unaccount_event_cpu(event, event->cpu); 4435 4436 unaccount_pmu_sb_event(event); 4437 } 4438 4439 static void perf_sched_delayed(struct work_struct *work) 4440 { 4441 mutex_lock(&perf_sched_mutex); 4442 if (atomic_dec_and_test(&perf_sched_count)) 4443 static_branch_disable(&perf_sched_events); 4444 mutex_unlock(&perf_sched_mutex); 4445 } 4446 4447 /* 4448 * The following implement mutual exclusion of events on "exclusive" pmus 4449 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled 4450 * at a time, so we disallow creating events that might conflict, namely: 4451 * 4452 * 1) cpu-wide events in the presence of per-task events, 4453 * 2) per-task events in the presence of cpu-wide events, 4454 * 3) two matching events on the same context. 4455 * 4456 * The former two cases are handled in the allocation path (perf_event_alloc(), 4457 * _free_event()), the latter -- before the first perf_install_in_context(). 4458 */ 4459 static int exclusive_event_init(struct perf_event *event) 4460 { 4461 struct pmu *pmu = event->pmu; 4462 4463 if (!is_exclusive_pmu(pmu)) 4464 return 0; 4465 4466 /* 4467 * Prevent co-existence of per-task and cpu-wide events on the 4468 * same exclusive pmu. 4469 * 4470 * Negative pmu::exclusive_cnt means there are cpu-wide 4471 * events on this "exclusive" pmu, positive means there are 4472 * per-task events. 4473 * 4474 * Since this is called in perf_event_alloc() path, event::ctx 4475 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK 4476 * to mean "per-task event", because unlike other attach states it 4477 * never gets cleared. 4478 */ 4479 if (event->attach_state & PERF_ATTACH_TASK) { 4480 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt)) 4481 return -EBUSY; 4482 } else { 4483 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt)) 4484 return -EBUSY; 4485 } 4486 4487 return 0; 4488 } 4489 4490 static void exclusive_event_destroy(struct perf_event *event) 4491 { 4492 struct pmu *pmu = event->pmu; 4493 4494 if (!is_exclusive_pmu(pmu)) 4495 return; 4496 4497 /* see comment in exclusive_event_init() */ 4498 if (event->attach_state & PERF_ATTACH_TASK) 4499 atomic_dec(&pmu->exclusive_cnt); 4500 else 4501 atomic_inc(&pmu->exclusive_cnt); 4502 } 4503 4504 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2) 4505 { 4506 if ((e1->pmu == e2->pmu) && 4507 (e1->cpu == e2->cpu || 4508 e1->cpu == -1 || 4509 e2->cpu == -1)) 4510 return true; 4511 return false; 4512 } 4513 4514 static bool exclusive_event_installable(struct perf_event *event, 4515 struct perf_event_context *ctx) 4516 { 4517 struct perf_event *iter_event; 4518 struct pmu *pmu = event->pmu; 4519 4520 lockdep_assert_held(&ctx->mutex); 4521 4522 if (!is_exclusive_pmu(pmu)) 4523 return true; 4524 4525 list_for_each_entry(iter_event, &ctx->event_list, event_entry) { 4526 if (exclusive_event_match(iter_event, event)) 4527 return false; 4528 } 4529 4530 return true; 4531 } 4532 4533 static void perf_addr_filters_splice(struct perf_event *event, 4534 struct list_head *head); 4535 4536 static void _free_event(struct perf_event *event) 4537 { 4538 irq_work_sync(&event->pending); 4539 4540 unaccount_event(event); 4541 4542 if (event->rb) { 4543 /* 4544 * Can happen when we close an event with re-directed output. 4545 * 4546 * Since we have a 0 refcount, perf_mmap_close() will skip 4547 * over us; possibly making our ring_buffer_put() the last. 4548 */ 4549 mutex_lock(&event->mmap_mutex); 4550 ring_buffer_attach(event, NULL); 4551 mutex_unlock(&event->mmap_mutex); 4552 } 4553 4554 if (is_cgroup_event(event)) 4555 perf_detach_cgroup(event); 4556 4557 if (!event->parent) { 4558 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) 4559 put_callchain_buffers(); 4560 } 4561 4562 perf_event_free_bpf_prog(event); 4563 perf_addr_filters_splice(event, NULL); 4564 kfree(event->addr_filter_ranges); 4565 4566 if (event->destroy) 4567 event->destroy(event); 4568 4569 /* 4570 * Must be after ->destroy(), due to uprobe_perf_close() using 4571 * hw.target. 4572 */ 4573 if (event->hw.target) 4574 put_task_struct(event->hw.target); 4575 4576 /* 4577 * perf_event_free_task() relies on put_ctx() being 'last', in particular 4578 * all task references must be cleaned up. 4579 */ 4580 if (event->ctx) 4581 put_ctx(event->ctx); 4582 4583 exclusive_event_destroy(event); 4584 module_put(event->pmu->module); 4585 4586 call_rcu(&event->rcu_head, free_event_rcu); 4587 } 4588 4589 /* 4590 * Used to free events which have a known refcount of 1, such as in error paths 4591 * where the event isn't exposed yet and inherited events. 4592 */ 4593 static void free_event(struct perf_event *event) 4594 { 4595 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1, 4596 "unexpected event refcount: %ld; ptr=%p\n", 4597 atomic_long_read(&event->refcount), event)) { 4598 /* leak to avoid use-after-free */ 4599 return; 4600 } 4601 4602 _free_event(event); 4603 } 4604 4605 /* 4606 * Remove user event from the owner task. 4607 */ 4608 static void perf_remove_from_owner(struct perf_event *event) 4609 { 4610 struct task_struct *owner; 4611 4612 rcu_read_lock(); 4613 /* 4614 * Matches the smp_store_release() in perf_event_exit_task(). If we 4615 * observe !owner it means the list deletion is complete and we can 4616 * indeed free this event, otherwise we need to serialize on 4617 * owner->perf_event_mutex. 4618 */ 4619 owner = READ_ONCE(event->owner); 4620 if (owner) { 4621 /* 4622 * Since delayed_put_task_struct() also drops the last 4623 * task reference we can safely take a new reference 4624 * while holding the rcu_read_lock(). 4625 */ 4626 get_task_struct(owner); 4627 } 4628 rcu_read_unlock(); 4629 4630 if (owner) { 4631 /* 4632 * If we're here through perf_event_exit_task() we're already 4633 * holding ctx->mutex which would be an inversion wrt. the 4634 * normal lock order. 4635 * 4636 * However we can safely take this lock because its the child 4637 * ctx->mutex. 4638 */ 4639 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING); 4640 4641 /* 4642 * We have to re-check the event->owner field, if it is cleared 4643 * we raced with perf_event_exit_task(), acquiring the mutex 4644 * ensured they're done, and we can proceed with freeing the 4645 * event. 4646 */ 4647 if (event->owner) { 4648 list_del_init(&event->owner_entry); 4649 smp_store_release(&event->owner, NULL); 4650 } 4651 mutex_unlock(&owner->perf_event_mutex); 4652 put_task_struct(owner); 4653 } 4654 } 4655 4656 static void put_event(struct perf_event *event) 4657 { 4658 if (!atomic_long_dec_and_test(&event->refcount)) 4659 return; 4660 4661 _free_event(event); 4662 } 4663 4664 /* 4665 * Kill an event dead; while event:refcount will preserve the event 4666 * object, it will not preserve its functionality. Once the last 'user' 4667 * gives up the object, we'll destroy the thing. 4668 */ 4669 int perf_event_release_kernel(struct perf_event *event) 4670 { 4671 struct perf_event_context *ctx = event->ctx; 4672 struct perf_event *child, *tmp; 4673 LIST_HEAD(free_list); 4674 4675 /* 4676 * If we got here through err_file: fput(event_file); we will not have 4677 * attached to a context yet. 4678 */ 4679 if (!ctx) { 4680 WARN_ON_ONCE(event->attach_state & 4681 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP)); 4682 goto no_ctx; 4683 } 4684 4685 if (!is_kernel_event(event)) 4686 perf_remove_from_owner(event); 4687 4688 ctx = perf_event_ctx_lock(event); 4689 WARN_ON_ONCE(ctx->parent_ctx); 4690 perf_remove_from_context(event, DETACH_GROUP); 4691 4692 raw_spin_lock_irq(&ctx->lock); 4693 /* 4694 * Mark this event as STATE_DEAD, there is no external reference to it 4695 * anymore. 4696 * 4697 * Anybody acquiring event->child_mutex after the below loop _must_ 4698 * also see this, most importantly inherit_event() which will avoid 4699 * placing more children on the list. 4700 * 4701 * Thus this guarantees that we will in fact observe and kill _ALL_ 4702 * child events. 4703 */ 4704 event->state = PERF_EVENT_STATE_DEAD; 4705 raw_spin_unlock_irq(&ctx->lock); 4706 4707 perf_event_ctx_unlock(event, ctx); 4708 4709 again: 4710 mutex_lock(&event->child_mutex); 4711 list_for_each_entry(child, &event->child_list, child_list) { 4712 4713 /* 4714 * Cannot change, child events are not migrated, see the 4715 * comment with perf_event_ctx_lock_nested(). 4716 */ 4717 ctx = READ_ONCE(child->ctx); 4718 /* 4719 * Since child_mutex nests inside ctx::mutex, we must jump 4720 * through hoops. We start by grabbing a reference on the ctx. 4721 * 4722 * Since the event cannot get freed while we hold the 4723 * child_mutex, the context must also exist and have a !0 4724 * reference count. 4725 */ 4726 get_ctx(ctx); 4727 4728 /* 4729 * Now that we have a ctx ref, we can drop child_mutex, and 4730 * acquire ctx::mutex without fear of it going away. Then we 4731 * can re-acquire child_mutex. 4732 */ 4733 mutex_unlock(&event->child_mutex); 4734 mutex_lock(&ctx->mutex); 4735 mutex_lock(&event->child_mutex); 4736 4737 /* 4738 * Now that we hold ctx::mutex and child_mutex, revalidate our 4739 * state, if child is still the first entry, it didn't get freed 4740 * and we can continue doing so. 4741 */ 4742 tmp = list_first_entry_or_null(&event->child_list, 4743 struct perf_event, child_list); 4744 if (tmp == child) { 4745 perf_remove_from_context(child, DETACH_GROUP); 4746 list_move(&child->child_list, &free_list); 4747 /* 4748 * This matches the refcount bump in inherit_event(); 4749 * this can't be the last reference. 4750 */ 4751 put_event(event); 4752 } 4753 4754 mutex_unlock(&event->child_mutex); 4755 mutex_unlock(&ctx->mutex); 4756 put_ctx(ctx); 4757 goto again; 4758 } 4759 mutex_unlock(&event->child_mutex); 4760 4761 list_for_each_entry_safe(child, tmp, &free_list, child_list) { 4762 void *var = &child->ctx->refcount; 4763 4764 list_del(&child->child_list); 4765 free_event(child); 4766 4767 /* 4768 * Wake any perf_event_free_task() waiting for this event to be 4769 * freed. 4770 */ 4771 smp_mb(); /* pairs with wait_var_event() */ 4772 wake_up_var(var); 4773 } 4774 4775 no_ctx: 4776 put_event(event); /* Must be the 'last' reference */ 4777 return 0; 4778 } 4779 EXPORT_SYMBOL_GPL(perf_event_release_kernel); 4780 4781 /* 4782 * Called when the last reference to the file is gone. 4783 */ 4784 static int perf_release(struct inode *inode, struct file *file) 4785 { 4786 perf_event_release_kernel(file->private_data); 4787 return 0; 4788 } 4789 4790 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) 4791 { 4792 struct perf_event *child; 4793 u64 total = 0; 4794 4795 *enabled = 0; 4796 *running = 0; 4797 4798 mutex_lock(&event->child_mutex); 4799 4800 (void)perf_event_read(event, false); 4801 total += perf_event_count(event); 4802 4803 *enabled += event->total_time_enabled + 4804 atomic64_read(&event->child_total_time_enabled); 4805 *running += event->total_time_running + 4806 atomic64_read(&event->child_total_time_running); 4807 4808 list_for_each_entry(child, &event->child_list, child_list) { 4809 (void)perf_event_read(child, false); 4810 total += perf_event_count(child); 4811 *enabled += child->total_time_enabled; 4812 *running += child->total_time_running; 4813 } 4814 mutex_unlock(&event->child_mutex); 4815 4816 return total; 4817 } 4818 4819 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) 4820 { 4821 struct perf_event_context *ctx; 4822 u64 count; 4823 4824 ctx = perf_event_ctx_lock(event); 4825 count = __perf_event_read_value(event, enabled, running); 4826 perf_event_ctx_unlock(event, ctx); 4827 4828 return count; 4829 } 4830 EXPORT_SYMBOL_GPL(perf_event_read_value); 4831 4832 static int __perf_read_group_add(struct perf_event *leader, 4833 u64 read_format, u64 *values) 4834 { 4835 struct perf_event_context *ctx = leader->ctx; 4836 struct perf_event *sub; 4837 unsigned long flags; 4838 int n = 1; /* skip @nr */ 4839 int ret; 4840 4841 ret = perf_event_read(leader, true); 4842 if (ret) 4843 return ret; 4844 4845 raw_spin_lock_irqsave(&ctx->lock, flags); 4846 4847 /* 4848 * Since we co-schedule groups, {enabled,running} times of siblings 4849 * will be identical to those of the leader, so we only publish one 4850 * set. 4851 */ 4852 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { 4853 values[n++] += leader->total_time_enabled + 4854 atomic64_read(&leader->child_total_time_enabled); 4855 } 4856 4857 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { 4858 values[n++] += leader->total_time_running + 4859 atomic64_read(&leader->child_total_time_running); 4860 } 4861 4862 /* 4863 * Write {count,id} tuples for every sibling. 4864 */ 4865 values[n++] += perf_event_count(leader); 4866 if (read_format & PERF_FORMAT_ID) 4867 values[n++] = primary_event_id(leader); 4868 4869 for_each_sibling_event(sub, leader) { 4870 values[n++] += perf_event_count(sub); 4871 if (read_format & PERF_FORMAT_ID) 4872 values[n++] = primary_event_id(sub); 4873 } 4874 4875 raw_spin_unlock_irqrestore(&ctx->lock, flags); 4876 return 0; 4877 } 4878 4879 static int perf_read_group(struct perf_event *event, 4880 u64 read_format, char __user *buf) 4881 { 4882 struct perf_event *leader = event->group_leader, *child; 4883 struct perf_event_context *ctx = leader->ctx; 4884 int ret; 4885 u64 *values; 4886 4887 lockdep_assert_held(&ctx->mutex); 4888 4889 values = kzalloc(event->read_size, GFP_KERNEL); 4890 if (!values) 4891 return -ENOMEM; 4892 4893 values[0] = 1 + leader->nr_siblings; 4894 4895 /* 4896 * By locking the child_mutex of the leader we effectively 4897 * lock the child list of all siblings.. XXX explain how. 4898 */ 4899 mutex_lock(&leader->child_mutex); 4900 4901 ret = __perf_read_group_add(leader, read_format, values); 4902 if (ret) 4903 goto unlock; 4904 4905 list_for_each_entry(child, &leader->child_list, child_list) { 4906 ret = __perf_read_group_add(child, read_format, values); 4907 if (ret) 4908 goto unlock; 4909 } 4910 4911 mutex_unlock(&leader->child_mutex); 4912 4913 ret = event->read_size; 4914 if (copy_to_user(buf, values, event->read_size)) 4915 ret = -EFAULT; 4916 goto out; 4917 4918 unlock: 4919 mutex_unlock(&leader->child_mutex); 4920 out: 4921 kfree(values); 4922 return ret; 4923 } 4924 4925 static int perf_read_one(struct perf_event *event, 4926 u64 read_format, char __user *buf) 4927 { 4928 u64 enabled, running; 4929 u64 values[4]; 4930 int n = 0; 4931 4932 values[n++] = __perf_event_read_value(event, &enabled, &running); 4933 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 4934 values[n++] = enabled; 4935 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 4936 values[n++] = running; 4937 if (read_format & PERF_FORMAT_ID) 4938 values[n++] = primary_event_id(event); 4939 4940 if (copy_to_user(buf, values, n * sizeof(u64))) 4941 return -EFAULT; 4942 4943 return n * sizeof(u64); 4944 } 4945 4946 static bool is_event_hup(struct perf_event *event) 4947 { 4948 bool no_children; 4949 4950 if (event->state > PERF_EVENT_STATE_EXIT) 4951 return false; 4952 4953 mutex_lock(&event->child_mutex); 4954 no_children = list_empty(&event->child_list); 4955 mutex_unlock(&event->child_mutex); 4956 return no_children; 4957 } 4958 4959 /* 4960 * Read the performance event - simple non blocking version for now 4961 */ 4962 static ssize_t 4963 __perf_read(struct perf_event *event, char __user *buf, size_t count) 4964 { 4965 u64 read_format = event->attr.read_format; 4966 int ret; 4967 4968 /* 4969 * Return end-of-file for a read on an event that is in 4970 * error state (i.e. because it was pinned but it couldn't be 4971 * scheduled on to the CPU at some point). 4972 */ 4973 if (event->state == PERF_EVENT_STATE_ERROR) 4974 return 0; 4975 4976 if (count < event->read_size) 4977 return -ENOSPC; 4978 4979 WARN_ON_ONCE(event->ctx->parent_ctx); 4980 if (read_format & PERF_FORMAT_GROUP) 4981 ret = perf_read_group(event, read_format, buf); 4982 else 4983 ret = perf_read_one(event, read_format, buf); 4984 4985 return ret; 4986 } 4987 4988 static ssize_t 4989 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 4990 { 4991 struct perf_event *event = file->private_data; 4992 struct perf_event_context *ctx; 4993 int ret; 4994 4995 ctx = perf_event_ctx_lock(event); 4996 ret = __perf_read(event, buf, count); 4997 perf_event_ctx_unlock(event, ctx); 4998 4999 return ret; 5000 } 5001 5002 static __poll_t perf_poll(struct file *file, poll_table *wait) 5003 { 5004 struct perf_event *event = file->private_data; 5005 struct ring_buffer *rb; 5006 __poll_t events = EPOLLHUP; 5007 5008 poll_wait(file, &event->waitq, wait); 5009 5010 if (is_event_hup(event)) 5011 return events; 5012 5013 /* 5014 * Pin the event->rb by taking event->mmap_mutex; otherwise 5015 * perf_event_set_output() can swizzle our rb and make us miss wakeups. 5016 */ 5017 mutex_lock(&event->mmap_mutex); 5018 rb = event->rb; 5019 if (rb) 5020 events = atomic_xchg(&rb->poll, 0); 5021 mutex_unlock(&event->mmap_mutex); 5022 return events; 5023 } 5024 5025 static void _perf_event_reset(struct perf_event *event) 5026 { 5027 (void)perf_event_read(event, false); 5028 local64_set(&event->count, 0); 5029 perf_event_update_userpage(event); 5030 } 5031 5032 /* 5033 * Holding the top-level event's child_mutex means that any 5034 * descendant process that has inherited this event will block 5035 * in perf_event_exit_event() if it goes to exit, thus satisfying the 5036 * task existence requirements of perf_event_enable/disable. 5037 */ 5038 static void perf_event_for_each_child(struct perf_event *event, 5039 void (*func)(struct perf_event *)) 5040 { 5041 struct perf_event *child; 5042 5043 WARN_ON_ONCE(event->ctx->parent_ctx); 5044 5045 mutex_lock(&event->child_mutex); 5046 func(event); 5047 list_for_each_entry(child, &event->child_list, child_list) 5048 func(child); 5049 mutex_unlock(&event->child_mutex); 5050 } 5051 5052 static void perf_event_for_each(struct perf_event *event, 5053 void (*func)(struct perf_event *)) 5054 { 5055 struct perf_event_context *ctx = event->ctx; 5056 struct perf_event *sibling; 5057 5058 lockdep_assert_held(&ctx->mutex); 5059 5060 event = event->group_leader; 5061 5062 perf_event_for_each_child(event, func); 5063 for_each_sibling_event(sibling, event) 5064 perf_event_for_each_child(sibling, func); 5065 } 5066 5067 static void __perf_event_period(struct perf_event *event, 5068 struct perf_cpu_context *cpuctx, 5069 struct perf_event_context *ctx, 5070 void *info) 5071 { 5072 u64 value = *((u64 *)info); 5073 bool active; 5074 5075 if (event->attr.freq) { 5076 event->attr.sample_freq = value; 5077 } else { 5078 event->attr.sample_period = value; 5079 event->hw.sample_period = value; 5080 } 5081 5082 active = (event->state == PERF_EVENT_STATE_ACTIVE); 5083 if (active) { 5084 perf_pmu_disable(ctx->pmu); 5085 /* 5086 * We could be throttled; unthrottle now to avoid the tick 5087 * trying to unthrottle while we already re-started the event. 5088 */ 5089 if (event->hw.interrupts == MAX_INTERRUPTS) { 5090 event->hw.interrupts = 0; 5091 perf_log_throttle(event, 1); 5092 } 5093 event->pmu->stop(event, PERF_EF_UPDATE); 5094 } 5095 5096 local64_set(&event->hw.period_left, 0); 5097 5098 if (active) { 5099 event->pmu->start(event, PERF_EF_RELOAD); 5100 perf_pmu_enable(ctx->pmu); 5101 } 5102 } 5103 5104 static int perf_event_check_period(struct perf_event *event, u64 value) 5105 { 5106 return event->pmu->check_period(event, value); 5107 } 5108 5109 static int perf_event_period(struct perf_event *event, u64 __user *arg) 5110 { 5111 u64 value; 5112 5113 if (!is_sampling_event(event)) 5114 return -EINVAL; 5115 5116 if (copy_from_user(&value, arg, sizeof(value))) 5117 return -EFAULT; 5118 5119 if (!value) 5120 return -EINVAL; 5121 5122 if (event->attr.freq && value > sysctl_perf_event_sample_rate) 5123 return -EINVAL; 5124 5125 if (perf_event_check_period(event, value)) 5126 return -EINVAL; 5127 5128 if (!event->attr.freq && (value & (1ULL << 63))) 5129 return -EINVAL; 5130 5131 event_function_call(event, __perf_event_period, &value); 5132 5133 return 0; 5134 } 5135 5136 static const struct file_operations perf_fops; 5137 5138 static inline int perf_fget_light(int fd, struct fd *p) 5139 { 5140 struct fd f = fdget(fd); 5141 if (!f.file) 5142 return -EBADF; 5143 5144 if (f.file->f_op != &perf_fops) { 5145 fdput(f); 5146 return -EBADF; 5147 } 5148 *p = f; 5149 return 0; 5150 } 5151 5152 static int perf_event_set_output(struct perf_event *event, 5153 struct perf_event *output_event); 5154 static int perf_event_set_filter(struct perf_event *event, void __user *arg); 5155 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd); 5156 static int perf_copy_attr(struct perf_event_attr __user *uattr, 5157 struct perf_event_attr *attr); 5158 5159 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg) 5160 { 5161 void (*func)(struct perf_event *); 5162 u32 flags = arg; 5163 5164 switch (cmd) { 5165 case PERF_EVENT_IOC_ENABLE: 5166 func = _perf_event_enable; 5167 break; 5168 case PERF_EVENT_IOC_DISABLE: 5169 func = _perf_event_disable; 5170 break; 5171 case PERF_EVENT_IOC_RESET: 5172 func = _perf_event_reset; 5173 break; 5174 5175 case PERF_EVENT_IOC_REFRESH: 5176 return _perf_event_refresh(event, arg); 5177 5178 case PERF_EVENT_IOC_PERIOD: 5179 return perf_event_period(event, (u64 __user *)arg); 5180 5181 case PERF_EVENT_IOC_ID: 5182 { 5183 u64 id = primary_event_id(event); 5184 5185 if (copy_to_user((void __user *)arg, &id, sizeof(id))) 5186 return -EFAULT; 5187 return 0; 5188 } 5189 5190 case PERF_EVENT_IOC_SET_OUTPUT: 5191 { 5192 int ret; 5193 if (arg != -1) { 5194 struct perf_event *output_event; 5195 struct fd output; 5196 ret = perf_fget_light(arg, &output); 5197 if (ret) 5198 return ret; 5199 output_event = output.file->private_data; 5200 ret = perf_event_set_output(event, output_event); 5201 fdput(output); 5202 } else { 5203 ret = perf_event_set_output(event, NULL); 5204 } 5205 return ret; 5206 } 5207 5208 case PERF_EVENT_IOC_SET_FILTER: 5209 return perf_event_set_filter(event, (void __user *)arg); 5210 5211 case PERF_EVENT_IOC_SET_BPF: 5212 return perf_event_set_bpf_prog(event, arg); 5213 5214 case PERF_EVENT_IOC_PAUSE_OUTPUT: { 5215 struct ring_buffer *rb; 5216 5217 rcu_read_lock(); 5218 rb = rcu_dereference(event->rb); 5219 if (!rb || !rb->nr_pages) { 5220 rcu_read_unlock(); 5221 return -EINVAL; 5222 } 5223 rb_toggle_paused(rb, !!arg); 5224 rcu_read_unlock(); 5225 return 0; 5226 } 5227 5228 case PERF_EVENT_IOC_QUERY_BPF: 5229 return perf_event_query_prog_array(event, (void __user *)arg); 5230 5231 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: { 5232 struct perf_event_attr new_attr; 5233 int err = perf_copy_attr((struct perf_event_attr __user *)arg, 5234 &new_attr); 5235 5236 if (err) 5237 return err; 5238 5239 return perf_event_modify_attr(event, &new_attr); 5240 } 5241 default: 5242 return -ENOTTY; 5243 } 5244 5245 if (flags & PERF_IOC_FLAG_GROUP) 5246 perf_event_for_each(event, func); 5247 else 5248 perf_event_for_each_child(event, func); 5249 5250 return 0; 5251 } 5252 5253 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 5254 { 5255 struct perf_event *event = file->private_data; 5256 struct perf_event_context *ctx; 5257 long ret; 5258 5259 ctx = perf_event_ctx_lock(event); 5260 ret = _perf_ioctl(event, cmd, arg); 5261 perf_event_ctx_unlock(event, ctx); 5262 5263 return ret; 5264 } 5265 5266 #ifdef CONFIG_COMPAT 5267 static long perf_compat_ioctl(struct file *file, unsigned int cmd, 5268 unsigned long arg) 5269 { 5270 switch (_IOC_NR(cmd)) { 5271 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER): 5272 case _IOC_NR(PERF_EVENT_IOC_ID): 5273 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF): 5274 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES): 5275 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */ 5276 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) { 5277 cmd &= ~IOCSIZE_MASK; 5278 cmd |= sizeof(void *) << IOCSIZE_SHIFT; 5279 } 5280 break; 5281 } 5282 return perf_ioctl(file, cmd, arg); 5283 } 5284 #else 5285 # define perf_compat_ioctl NULL 5286 #endif 5287 5288 int perf_event_task_enable(void) 5289 { 5290 struct perf_event_context *ctx; 5291 struct perf_event *event; 5292 5293 mutex_lock(¤t->perf_event_mutex); 5294 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { 5295 ctx = perf_event_ctx_lock(event); 5296 perf_event_for_each_child(event, _perf_event_enable); 5297 perf_event_ctx_unlock(event, ctx); 5298 } 5299 mutex_unlock(¤t->perf_event_mutex); 5300 5301 return 0; 5302 } 5303 5304 int perf_event_task_disable(void) 5305 { 5306 struct perf_event_context *ctx; 5307 struct perf_event *event; 5308 5309 mutex_lock(¤t->perf_event_mutex); 5310 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { 5311 ctx = perf_event_ctx_lock(event); 5312 perf_event_for_each_child(event, _perf_event_disable); 5313 perf_event_ctx_unlock(event, ctx); 5314 } 5315 mutex_unlock(¤t->perf_event_mutex); 5316 5317 return 0; 5318 } 5319 5320 static int perf_event_index(struct perf_event *event) 5321 { 5322 if (event->hw.state & PERF_HES_STOPPED) 5323 return 0; 5324 5325 if (event->state != PERF_EVENT_STATE_ACTIVE) 5326 return 0; 5327 5328 return event->pmu->event_idx(event); 5329 } 5330 5331 static void calc_timer_values(struct perf_event *event, 5332 u64 *now, 5333 u64 *enabled, 5334 u64 *running) 5335 { 5336 u64 ctx_time; 5337 5338 *now = perf_clock(); 5339 ctx_time = event->shadow_ctx_time + *now; 5340 __perf_update_times(event, ctx_time, enabled, running); 5341 } 5342 5343 static void perf_event_init_userpage(struct perf_event *event) 5344 { 5345 struct perf_event_mmap_page *userpg; 5346 struct ring_buffer *rb; 5347 5348 rcu_read_lock(); 5349 rb = rcu_dereference(event->rb); 5350 if (!rb) 5351 goto unlock; 5352 5353 userpg = rb->user_page; 5354 5355 /* Allow new userspace to detect that bit 0 is deprecated */ 5356 userpg->cap_bit0_is_deprecated = 1; 5357 userpg->size = offsetof(struct perf_event_mmap_page, __reserved); 5358 userpg->data_offset = PAGE_SIZE; 5359 userpg->data_size = perf_data_size(rb); 5360 5361 unlock: 5362 rcu_read_unlock(); 5363 } 5364 5365 void __weak arch_perf_update_userpage( 5366 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now) 5367 { 5368 } 5369 5370 /* 5371 * Callers need to ensure there can be no nesting of this function, otherwise 5372 * the seqlock logic goes bad. We can not serialize this because the arch 5373 * code calls this from NMI context. 5374 */ 5375 void perf_event_update_userpage(struct perf_event *event) 5376 { 5377 struct perf_event_mmap_page *userpg; 5378 struct ring_buffer *rb; 5379 u64 enabled, running, now; 5380 5381 rcu_read_lock(); 5382 rb = rcu_dereference(event->rb); 5383 if (!rb) 5384 goto unlock; 5385 5386 /* 5387 * compute total_time_enabled, total_time_running 5388 * based on snapshot values taken when the event 5389 * was last scheduled in. 5390 * 5391 * we cannot simply called update_context_time() 5392 * because of locking issue as we can be called in 5393 * NMI context 5394 */ 5395 calc_timer_values(event, &now, &enabled, &running); 5396 5397 userpg = rb->user_page; 5398 /* 5399 * Disable preemption to guarantee consistent time stamps are stored to 5400 * the user page. 5401 */ 5402 preempt_disable(); 5403 ++userpg->lock; 5404 barrier(); 5405 userpg->index = perf_event_index(event); 5406 userpg->offset = perf_event_count(event); 5407 if (userpg->index) 5408 userpg->offset -= local64_read(&event->hw.prev_count); 5409 5410 userpg->time_enabled = enabled + 5411 atomic64_read(&event->child_total_time_enabled); 5412 5413 userpg->time_running = running + 5414 atomic64_read(&event->child_total_time_running); 5415 5416 arch_perf_update_userpage(event, userpg, now); 5417 5418 barrier(); 5419 ++userpg->lock; 5420 preempt_enable(); 5421 unlock: 5422 rcu_read_unlock(); 5423 } 5424 EXPORT_SYMBOL_GPL(perf_event_update_userpage); 5425 5426 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf) 5427 { 5428 struct perf_event *event = vmf->vma->vm_file->private_data; 5429 struct ring_buffer *rb; 5430 vm_fault_t ret = VM_FAULT_SIGBUS; 5431 5432 if (vmf->flags & FAULT_FLAG_MKWRITE) { 5433 if (vmf->pgoff == 0) 5434 ret = 0; 5435 return ret; 5436 } 5437 5438 rcu_read_lock(); 5439 rb = rcu_dereference(event->rb); 5440 if (!rb) 5441 goto unlock; 5442 5443 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE)) 5444 goto unlock; 5445 5446 vmf->page = perf_mmap_to_page(rb, vmf->pgoff); 5447 if (!vmf->page) 5448 goto unlock; 5449 5450 get_page(vmf->page); 5451 vmf->page->mapping = vmf->vma->vm_file->f_mapping; 5452 vmf->page->index = vmf->pgoff; 5453 5454 ret = 0; 5455 unlock: 5456 rcu_read_unlock(); 5457 5458 return ret; 5459 } 5460 5461 static void ring_buffer_attach(struct perf_event *event, 5462 struct ring_buffer *rb) 5463 { 5464 struct ring_buffer *old_rb = NULL; 5465 unsigned long flags; 5466 5467 if (event->rb) { 5468 /* 5469 * Should be impossible, we set this when removing 5470 * event->rb_entry and wait/clear when adding event->rb_entry. 5471 */ 5472 WARN_ON_ONCE(event->rcu_pending); 5473 5474 old_rb = event->rb; 5475 spin_lock_irqsave(&old_rb->event_lock, flags); 5476 list_del_rcu(&event->rb_entry); 5477 spin_unlock_irqrestore(&old_rb->event_lock, flags); 5478 5479 event->rcu_batches = get_state_synchronize_rcu(); 5480 event->rcu_pending = 1; 5481 } 5482 5483 if (rb) { 5484 if (event->rcu_pending) { 5485 cond_synchronize_rcu(event->rcu_batches); 5486 event->rcu_pending = 0; 5487 } 5488 5489 spin_lock_irqsave(&rb->event_lock, flags); 5490 list_add_rcu(&event->rb_entry, &rb->event_list); 5491 spin_unlock_irqrestore(&rb->event_lock, flags); 5492 } 5493 5494 /* 5495 * Avoid racing with perf_mmap_close(AUX): stop the event 5496 * before swizzling the event::rb pointer; if it's getting 5497 * unmapped, its aux_mmap_count will be 0 and it won't 5498 * restart. See the comment in __perf_pmu_output_stop(). 5499 * 5500 * Data will inevitably be lost when set_output is done in 5501 * mid-air, but then again, whoever does it like this is 5502 * not in for the data anyway. 5503 */ 5504 if (has_aux(event)) 5505 perf_event_stop(event, 0); 5506 5507 rcu_assign_pointer(event->rb, rb); 5508 5509 if (old_rb) { 5510 ring_buffer_put(old_rb); 5511 /* 5512 * Since we detached before setting the new rb, so that we 5513 * could attach the new rb, we could have missed a wakeup. 5514 * Provide it now. 5515 */ 5516 wake_up_all(&event->waitq); 5517 } 5518 } 5519 5520 static void ring_buffer_wakeup(struct perf_event *event) 5521 { 5522 struct ring_buffer *rb; 5523 5524 rcu_read_lock(); 5525 rb = rcu_dereference(event->rb); 5526 if (rb) { 5527 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) 5528 wake_up_all(&event->waitq); 5529 } 5530 rcu_read_unlock(); 5531 } 5532 5533 struct ring_buffer *ring_buffer_get(struct perf_event *event) 5534 { 5535 struct ring_buffer *rb; 5536 5537 rcu_read_lock(); 5538 rb = rcu_dereference(event->rb); 5539 if (rb) { 5540 if (!refcount_inc_not_zero(&rb->refcount)) 5541 rb = NULL; 5542 } 5543 rcu_read_unlock(); 5544 5545 return rb; 5546 } 5547 5548 void ring_buffer_put(struct ring_buffer *rb) 5549 { 5550 if (!refcount_dec_and_test(&rb->refcount)) 5551 return; 5552 5553 WARN_ON_ONCE(!list_empty(&rb->event_list)); 5554 5555 call_rcu(&rb->rcu_head, rb_free_rcu); 5556 } 5557 5558 static void perf_mmap_open(struct vm_area_struct *vma) 5559 { 5560 struct perf_event *event = vma->vm_file->private_data; 5561 5562 atomic_inc(&event->mmap_count); 5563 atomic_inc(&event->rb->mmap_count); 5564 5565 if (vma->vm_pgoff) 5566 atomic_inc(&event->rb->aux_mmap_count); 5567 5568 if (event->pmu->event_mapped) 5569 event->pmu->event_mapped(event, vma->vm_mm); 5570 } 5571 5572 static void perf_pmu_output_stop(struct perf_event *event); 5573 5574 /* 5575 * A buffer can be mmap()ed multiple times; either directly through the same 5576 * event, or through other events by use of perf_event_set_output(). 5577 * 5578 * In order to undo the VM accounting done by perf_mmap() we need to destroy 5579 * the buffer here, where we still have a VM context. This means we need 5580 * to detach all events redirecting to us. 5581 */ 5582 static void perf_mmap_close(struct vm_area_struct *vma) 5583 { 5584 struct perf_event *event = vma->vm_file->private_data; 5585 5586 struct ring_buffer *rb = ring_buffer_get(event); 5587 struct user_struct *mmap_user = rb->mmap_user; 5588 int mmap_locked = rb->mmap_locked; 5589 unsigned long size = perf_data_size(rb); 5590 5591 if (event->pmu->event_unmapped) 5592 event->pmu->event_unmapped(event, vma->vm_mm); 5593 5594 /* 5595 * rb->aux_mmap_count will always drop before rb->mmap_count and 5596 * event->mmap_count, so it is ok to use event->mmap_mutex to 5597 * serialize with perf_mmap here. 5598 */ 5599 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff && 5600 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) { 5601 /* 5602 * Stop all AUX events that are writing to this buffer, 5603 * so that we can free its AUX pages and corresponding PMU 5604 * data. Note that after rb::aux_mmap_count dropped to zero, 5605 * they won't start any more (see perf_aux_output_begin()). 5606 */ 5607 perf_pmu_output_stop(event); 5608 5609 /* now it's safe to free the pages */ 5610 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm); 5611 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm); 5612 5613 /* this has to be the last one */ 5614 rb_free_aux(rb); 5615 WARN_ON_ONCE(refcount_read(&rb->aux_refcount)); 5616 5617 mutex_unlock(&event->mmap_mutex); 5618 } 5619 5620 atomic_dec(&rb->mmap_count); 5621 5622 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) 5623 goto out_put; 5624 5625 ring_buffer_attach(event, NULL); 5626 mutex_unlock(&event->mmap_mutex); 5627 5628 /* If there's still other mmap()s of this buffer, we're done. */ 5629 if (atomic_read(&rb->mmap_count)) 5630 goto out_put; 5631 5632 /* 5633 * No other mmap()s, detach from all other events that might redirect 5634 * into the now unreachable buffer. Somewhat complicated by the 5635 * fact that rb::event_lock otherwise nests inside mmap_mutex. 5636 */ 5637 again: 5638 rcu_read_lock(); 5639 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) { 5640 if (!atomic_long_inc_not_zero(&event->refcount)) { 5641 /* 5642 * This event is en-route to free_event() which will 5643 * detach it and remove it from the list. 5644 */ 5645 continue; 5646 } 5647 rcu_read_unlock(); 5648 5649 mutex_lock(&event->mmap_mutex); 5650 /* 5651 * Check we didn't race with perf_event_set_output() which can 5652 * swizzle the rb from under us while we were waiting to 5653 * acquire mmap_mutex. 5654 * 5655 * If we find a different rb; ignore this event, a next 5656 * iteration will no longer find it on the list. We have to 5657 * still restart the iteration to make sure we're not now 5658 * iterating the wrong list. 5659 */ 5660 if (event->rb == rb) 5661 ring_buffer_attach(event, NULL); 5662 5663 mutex_unlock(&event->mmap_mutex); 5664 put_event(event); 5665 5666 /* 5667 * Restart the iteration; either we're on the wrong list or 5668 * destroyed its integrity by doing a deletion. 5669 */ 5670 goto again; 5671 } 5672 rcu_read_unlock(); 5673 5674 /* 5675 * It could be there's still a few 0-ref events on the list; they'll 5676 * get cleaned up by free_event() -- they'll also still have their 5677 * ref on the rb and will free it whenever they are done with it. 5678 * 5679 * Aside from that, this buffer is 'fully' detached and unmapped, 5680 * undo the VM accounting. 5681 */ 5682 5683 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked, 5684 &mmap_user->locked_vm); 5685 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm); 5686 free_uid(mmap_user); 5687 5688 out_put: 5689 ring_buffer_put(rb); /* could be last */ 5690 } 5691 5692 static const struct vm_operations_struct perf_mmap_vmops = { 5693 .open = perf_mmap_open, 5694 .close = perf_mmap_close, /* non mergeable */ 5695 .fault = perf_mmap_fault, 5696 .page_mkwrite = perf_mmap_fault, 5697 }; 5698 5699 static int perf_mmap(struct file *file, struct vm_area_struct *vma) 5700 { 5701 struct perf_event *event = file->private_data; 5702 unsigned long user_locked, user_lock_limit; 5703 struct user_struct *user = current_user(); 5704 unsigned long locked, lock_limit; 5705 struct ring_buffer *rb = NULL; 5706 unsigned long vma_size; 5707 unsigned long nr_pages; 5708 long user_extra = 0, extra = 0; 5709 int ret = 0, flags = 0; 5710 5711 /* 5712 * Don't allow mmap() of inherited per-task counters. This would 5713 * create a performance issue due to all children writing to the 5714 * same rb. 5715 */ 5716 if (event->cpu == -1 && event->attr.inherit) 5717 return -EINVAL; 5718 5719 if (!(vma->vm_flags & VM_SHARED)) 5720 return -EINVAL; 5721 5722 vma_size = vma->vm_end - vma->vm_start; 5723 5724 if (vma->vm_pgoff == 0) { 5725 nr_pages = (vma_size / PAGE_SIZE) - 1; 5726 } else { 5727 /* 5728 * AUX area mapping: if rb->aux_nr_pages != 0, it's already 5729 * mapped, all subsequent mappings should have the same size 5730 * and offset. Must be above the normal perf buffer. 5731 */ 5732 u64 aux_offset, aux_size; 5733 5734 if (!event->rb) 5735 return -EINVAL; 5736 5737 nr_pages = vma_size / PAGE_SIZE; 5738 5739 mutex_lock(&event->mmap_mutex); 5740 ret = -EINVAL; 5741 5742 rb = event->rb; 5743 if (!rb) 5744 goto aux_unlock; 5745 5746 aux_offset = READ_ONCE(rb->user_page->aux_offset); 5747 aux_size = READ_ONCE(rb->user_page->aux_size); 5748 5749 if (aux_offset < perf_data_size(rb) + PAGE_SIZE) 5750 goto aux_unlock; 5751 5752 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT) 5753 goto aux_unlock; 5754 5755 /* already mapped with a different offset */ 5756 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff) 5757 goto aux_unlock; 5758 5759 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE) 5760 goto aux_unlock; 5761 5762 /* already mapped with a different size */ 5763 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages) 5764 goto aux_unlock; 5765 5766 if (!is_power_of_2(nr_pages)) 5767 goto aux_unlock; 5768 5769 if (!atomic_inc_not_zero(&rb->mmap_count)) 5770 goto aux_unlock; 5771 5772 if (rb_has_aux(rb)) { 5773 atomic_inc(&rb->aux_mmap_count); 5774 ret = 0; 5775 goto unlock; 5776 } 5777 5778 atomic_set(&rb->aux_mmap_count, 1); 5779 user_extra = nr_pages; 5780 5781 goto accounting; 5782 } 5783 5784 /* 5785 * If we have rb pages ensure they're a power-of-two number, so we 5786 * can do bitmasks instead of modulo. 5787 */ 5788 if (nr_pages != 0 && !is_power_of_2(nr_pages)) 5789 return -EINVAL; 5790 5791 if (vma_size != PAGE_SIZE * (1 + nr_pages)) 5792 return -EINVAL; 5793 5794 WARN_ON_ONCE(event->ctx->parent_ctx); 5795 again: 5796 mutex_lock(&event->mmap_mutex); 5797 if (event->rb) { 5798 if (event->rb->nr_pages != nr_pages) { 5799 ret = -EINVAL; 5800 goto unlock; 5801 } 5802 5803 if (!atomic_inc_not_zero(&event->rb->mmap_count)) { 5804 /* 5805 * Raced against perf_mmap_close() through 5806 * perf_event_set_output(). Try again, hope for better 5807 * luck. 5808 */ 5809 mutex_unlock(&event->mmap_mutex); 5810 goto again; 5811 } 5812 5813 goto unlock; 5814 } 5815 5816 user_extra = nr_pages + 1; 5817 5818 accounting: 5819 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10); 5820 5821 /* 5822 * Increase the limit linearly with more CPUs: 5823 */ 5824 user_lock_limit *= num_online_cpus(); 5825 5826 user_locked = atomic_long_read(&user->locked_vm) + user_extra; 5827 5828 if (user_locked <= user_lock_limit) { 5829 /* charge all to locked_vm */ 5830 } else if (atomic_long_read(&user->locked_vm) >= user_lock_limit) { 5831 /* charge all to pinned_vm */ 5832 extra = user_extra; 5833 user_extra = 0; 5834 } else { 5835 /* 5836 * charge locked_vm until it hits user_lock_limit; 5837 * charge the rest from pinned_vm 5838 */ 5839 extra = user_locked - user_lock_limit; 5840 user_extra -= extra; 5841 } 5842 5843 lock_limit = rlimit(RLIMIT_MEMLOCK); 5844 lock_limit >>= PAGE_SHIFT; 5845 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra; 5846 5847 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() && 5848 !capable(CAP_IPC_LOCK)) { 5849 ret = -EPERM; 5850 goto unlock; 5851 } 5852 5853 WARN_ON(!rb && event->rb); 5854 5855 if (vma->vm_flags & VM_WRITE) 5856 flags |= RING_BUFFER_WRITABLE; 5857 5858 if (!rb) { 5859 rb = rb_alloc(nr_pages, 5860 event->attr.watermark ? event->attr.wakeup_watermark : 0, 5861 event->cpu, flags); 5862 5863 if (!rb) { 5864 ret = -ENOMEM; 5865 goto unlock; 5866 } 5867 5868 atomic_set(&rb->mmap_count, 1); 5869 rb->mmap_user = get_current_user(); 5870 rb->mmap_locked = extra; 5871 5872 ring_buffer_attach(event, rb); 5873 5874 perf_event_init_userpage(event); 5875 perf_event_update_userpage(event); 5876 } else { 5877 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages, 5878 event->attr.aux_watermark, flags); 5879 if (!ret) 5880 rb->aux_mmap_locked = extra; 5881 } 5882 5883 unlock: 5884 if (!ret) { 5885 atomic_long_add(user_extra, &user->locked_vm); 5886 atomic64_add(extra, &vma->vm_mm->pinned_vm); 5887 5888 atomic_inc(&event->mmap_count); 5889 } else if (rb) { 5890 atomic_dec(&rb->mmap_count); 5891 } 5892 aux_unlock: 5893 mutex_unlock(&event->mmap_mutex); 5894 5895 /* 5896 * Since pinned accounting is per vm we cannot allow fork() to copy our 5897 * vma. 5898 */ 5899 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP; 5900 vma->vm_ops = &perf_mmap_vmops; 5901 5902 if (event->pmu->event_mapped) 5903 event->pmu->event_mapped(event, vma->vm_mm); 5904 5905 return ret; 5906 } 5907 5908 static int perf_fasync(int fd, struct file *filp, int on) 5909 { 5910 struct inode *inode = file_inode(filp); 5911 struct perf_event *event = filp->private_data; 5912 int retval; 5913 5914 inode_lock(inode); 5915 retval = fasync_helper(fd, filp, on, &event->fasync); 5916 inode_unlock(inode); 5917 5918 if (retval < 0) 5919 return retval; 5920 5921 return 0; 5922 } 5923 5924 static const struct file_operations perf_fops = { 5925 .llseek = no_llseek, 5926 .release = perf_release, 5927 .read = perf_read, 5928 .poll = perf_poll, 5929 .unlocked_ioctl = perf_ioctl, 5930 .compat_ioctl = perf_compat_ioctl, 5931 .mmap = perf_mmap, 5932 .fasync = perf_fasync, 5933 }; 5934 5935 /* 5936 * Perf event wakeup 5937 * 5938 * If there's data, ensure we set the poll() state and publish everything 5939 * to user-space before waking everybody up. 5940 */ 5941 5942 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event) 5943 { 5944 /* only the parent has fasync state */ 5945 if (event->parent) 5946 event = event->parent; 5947 return &event->fasync; 5948 } 5949 5950 void perf_event_wakeup(struct perf_event *event) 5951 { 5952 ring_buffer_wakeup(event); 5953 5954 if (event->pending_kill) { 5955 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill); 5956 event->pending_kill = 0; 5957 } 5958 } 5959 5960 static void perf_pending_event_disable(struct perf_event *event) 5961 { 5962 int cpu = READ_ONCE(event->pending_disable); 5963 5964 if (cpu < 0) 5965 return; 5966 5967 if (cpu == smp_processor_id()) { 5968 WRITE_ONCE(event->pending_disable, -1); 5969 perf_event_disable_local(event); 5970 return; 5971 } 5972 5973 /* 5974 * CPU-A CPU-B 5975 * 5976 * perf_event_disable_inatomic() 5977 * @pending_disable = CPU-A; 5978 * irq_work_queue(); 5979 * 5980 * sched-out 5981 * @pending_disable = -1; 5982 * 5983 * sched-in 5984 * perf_event_disable_inatomic() 5985 * @pending_disable = CPU-B; 5986 * irq_work_queue(); // FAILS 5987 * 5988 * irq_work_run() 5989 * perf_pending_event() 5990 * 5991 * But the event runs on CPU-B and wants disabling there. 5992 */ 5993 irq_work_queue_on(&event->pending, cpu); 5994 } 5995 5996 static void perf_pending_event(struct irq_work *entry) 5997 { 5998 struct perf_event *event = container_of(entry, struct perf_event, pending); 5999 int rctx; 6000 6001 rctx = perf_swevent_get_recursion_context(); 6002 /* 6003 * If we 'fail' here, that's OK, it means recursion is already disabled 6004 * and we won't recurse 'further'. 6005 */ 6006 6007 perf_pending_event_disable(event); 6008 6009 if (event->pending_wakeup) { 6010 event->pending_wakeup = 0; 6011 perf_event_wakeup(event); 6012 } 6013 6014 if (rctx >= 0) 6015 perf_swevent_put_recursion_context(rctx); 6016 } 6017 6018 /* 6019 * We assume there is only KVM supporting the callbacks. 6020 * Later on, we might change it to a list if there is 6021 * another virtualization implementation supporting the callbacks. 6022 */ 6023 struct perf_guest_info_callbacks *perf_guest_cbs; 6024 6025 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) 6026 { 6027 perf_guest_cbs = cbs; 6028 return 0; 6029 } 6030 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks); 6031 6032 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) 6033 { 6034 perf_guest_cbs = NULL; 6035 return 0; 6036 } 6037 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks); 6038 6039 static void 6040 perf_output_sample_regs(struct perf_output_handle *handle, 6041 struct pt_regs *regs, u64 mask) 6042 { 6043 int bit; 6044 DECLARE_BITMAP(_mask, 64); 6045 6046 bitmap_from_u64(_mask, mask); 6047 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) { 6048 u64 val; 6049 6050 val = perf_reg_value(regs, bit); 6051 perf_output_put(handle, val); 6052 } 6053 } 6054 6055 static void perf_sample_regs_user(struct perf_regs *regs_user, 6056 struct pt_regs *regs, 6057 struct pt_regs *regs_user_copy) 6058 { 6059 if (user_mode(regs)) { 6060 regs_user->abi = perf_reg_abi(current); 6061 regs_user->regs = regs; 6062 } else if (!(current->flags & PF_KTHREAD)) { 6063 perf_get_regs_user(regs_user, regs, regs_user_copy); 6064 } else { 6065 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE; 6066 regs_user->regs = NULL; 6067 } 6068 } 6069 6070 static void perf_sample_regs_intr(struct perf_regs *regs_intr, 6071 struct pt_regs *regs) 6072 { 6073 regs_intr->regs = regs; 6074 regs_intr->abi = perf_reg_abi(current); 6075 } 6076 6077 6078 /* 6079 * Get remaining task size from user stack pointer. 6080 * 6081 * It'd be better to take stack vma map and limit this more 6082 * precisely, but there's no way to get it safely under interrupt, 6083 * so using TASK_SIZE as limit. 6084 */ 6085 static u64 perf_ustack_task_size(struct pt_regs *regs) 6086 { 6087 unsigned long addr = perf_user_stack_pointer(regs); 6088 6089 if (!addr || addr >= TASK_SIZE) 6090 return 0; 6091 6092 return TASK_SIZE - addr; 6093 } 6094 6095 static u16 6096 perf_sample_ustack_size(u16 stack_size, u16 header_size, 6097 struct pt_regs *regs) 6098 { 6099 u64 task_size; 6100 6101 /* No regs, no stack pointer, no dump. */ 6102 if (!regs) 6103 return 0; 6104 6105 /* 6106 * Check if we fit in with the requested stack size into the: 6107 * - TASK_SIZE 6108 * If we don't, we limit the size to the TASK_SIZE. 6109 * 6110 * - remaining sample size 6111 * If we don't, we customize the stack size to 6112 * fit in to the remaining sample size. 6113 */ 6114 6115 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs)); 6116 stack_size = min(stack_size, (u16) task_size); 6117 6118 /* Current header size plus static size and dynamic size. */ 6119 header_size += 2 * sizeof(u64); 6120 6121 /* Do we fit in with the current stack dump size? */ 6122 if ((u16) (header_size + stack_size) < header_size) { 6123 /* 6124 * If we overflow the maximum size for the sample, 6125 * we customize the stack dump size to fit in. 6126 */ 6127 stack_size = USHRT_MAX - header_size - sizeof(u64); 6128 stack_size = round_up(stack_size, sizeof(u64)); 6129 } 6130 6131 return stack_size; 6132 } 6133 6134 static void 6135 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size, 6136 struct pt_regs *regs) 6137 { 6138 /* Case of a kernel thread, nothing to dump */ 6139 if (!regs) { 6140 u64 size = 0; 6141 perf_output_put(handle, size); 6142 } else { 6143 unsigned long sp; 6144 unsigned int rem; 6145 u64 dyn_size; 6146 mm_segment_t fs; 6147 6148 /* 6149 * We dump: 6150 * static size 6151 * - the size requested by user or the best one we can fit 6152 * in to the sample max size 6153 * data 6154 * - user stack dump data 6155 * dynamic size 6156 * - the actual dumped size 6157 */ 6158 6159 /* Static size. */ 6160 perf_output_put(handle, dump_size); 6161 6162 /* Data. */ 6163 sp = perf_user_stack_pointer(regs); 6164 fs = get_fs(); 6165 set_fs(USER_DS); 6166 rem = __output_copy_user(handle, (void *) sp, dump_size); 6167 set_fs(fs); 6168 dyn_size = dump_size - rem; 6169 6170 perf_output_skip(handle, rem); 6171 6172 /* Dynamic size. */ 6173 perf_output_put(handle, dyn_size); 6174 } 6175 } 6176 6177 static void __perf_event_header__init_id(struct perf_event_header *header, 6178 struct perf_sample_data *data, 6179 struct perf_event *event) 6180 { 6181 u64 sample_type = event->attr.sample_type; 6182 6183 data->type = sample_type; 6184 header->size += event->id_header_size; 6185 6186 if (sample_type & PERF_SAMPLE_TID) { 6187 /* namespace issues */ 6188 data->tid_entry.pid = perf_event_pid(event, current); 6189 data->tid_entry.tid = perf_event_tid(event, current); 6190 } 6191 6192 if (sample_type & PERF_SAMPLE_TIME) 6193 data->time = perf_event_clock(event); 6194 6195 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER)) 6196 data->id = primary_event_id(event); 6197 6198 if (sample_type & PERF_SAMPLE_STREAM_ID) 6199 data->stream_id = event->id; 6200 6201 if (sample_type & PERF_SAMPLE_CPU) { 6202 data->cpu_entry.cpu = raw_smp_processor_id(); 6203 data->cpu_entry.reserved = 0; 6204 } 6205 } 6206 6207 void perf_event_header__init_id(struct perf_event_header *header, 6208 struct perf_sample_data *data, 6209 struct perf_event *event) 6210 { 6211 if (event->attr.sample_id_all) 6212 __perf_event_header__init_id(header, data, event); 6213 } 6214 6215 static void __perf_event__output_id_sample(struct perf_output_handle *handle, 6216 struct perf_sample_data *data) 6217 { 6218 u64 sample_type = data->type; 6219 6220 if (sample_type & PERF_SAMPLE_TID) 6221 perf_output_put(handle, data->tid_entry); 6222 6223 if (sample_type & PERF_SAMPLE_TIME) 6224 perf_output_put(handle, data->time); 6225 6226 if (sample_type & PERF_SAMPLE_ID) 6227 perf_output_put(handle, data->id); 6228 6229 if (sample_type & PERF_SAMPLE_STREAM_ID) 6230 perf_output_put(handle, data->stream_id); 6231 6232 if (sample_type & PERF_SAMPLE_CPU) 6233 perf_output_put(handle, data->cpu_entry); 6234 6235 if (sample_type & PERF_SAMPLE_IDENTIFIER) 6236 perf_output_put(handle, data->id); 6237 } 6238 6239 void perf_event__output_id_sample(struct perf_event *event, 6240 struct perf_output_handle *handle, 6241 struct perf_sample_data *sample) 6242 { 6243 if (event->attr.sample_id_all) 6244 __perf_event__output_id_sample(handle, sample); 6245 } 6246 6247 static void perf_output_read_one(struct perf_output_handle *handle, 6248 struct perf_event *event, 6249 u64 enabled, u64 running) 6250 { 6251 u64 read_format = event->attr.read_format; 6252 u64 values[4]; 6253 int n = 0; 6254 6255 values[n++] = perf_event_count(event); 6256 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { 6257 values[n++] = enabled + 6258 atomic64_read(&event->child_total_time_enabled); 6259 } 6260 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { 6261 values[n++] = running + 6262 atomic64_read(&event->child_total_time_running); 6263 } 6264 if (read_format & PERF_FORMAT_ID) 6265 values[n++] = primary_event_id(event); 6266 6267 __output_copy(handle, values, n * sizeof(u64)); 6268 } 6269 6270 static void perf_output_read_group(struct perf_output_handle *handle, 6271 struct perf_event *event, 6272 u64 enabled, u64 running) 6273 { 6274 struct perf_event *leader = event->group_leader, *sub; 6275 u64 read_format = event->attr.read_format; 6276 u64 values[5]; 6277 int n = 0; 6278 6279 values[n++] = 1 + leader->nr_siblings; 6280 6281 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 6282 values[n++] = enabled; 6283 6284 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 6285 values[n++] = running; 6286 6287 if ((leader != event) && 6288 (leader->state == PERF_EVENT_STATE_ACTIVE)) 6289 leader->pmu->read(leader); 6290 6291 values[n++] = perf_event_count(leader); 6292 if (read_format & PERF_FORMAT_ID) 6293 values[n++] = primary_event_id(leader); 6294 6295 __output_copy(handle, values, n * sizeof(u64)); 6296 6297 for_each_sibling_event(sub, leader) { 6298 n = 0; 6299 6300 if ((sub != event) && 6301 (sub->state == PERF_EVENT_STATE_ACTIVE)) 6302 sub->pmu->read(sub); 6303 6304 values[n++] = perf_event_count(sub); 6305 if (read_format & PERF_FORMAT_ID) 6306 values[n++] = primary_event_id(sub); 6307 6308 __output_copy(handle, values, n * sizeof(u64)); 6309 } 6310 } 6311 6312 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\ 6313 PERF_FORMAT_TOTAL_TIME_RUNNING) 6314 6315 /* 6316 * XXX PERF_SAMPLE_READ vs inherited events seems difficult. 6317 * 6318 * The problem is that its both hard and excessively expensive to iterate the 6319 * child list, not to mention that its impossible to IPI the children running 6320 * on another CPU, from interrupt/NMI context. 6321 */ 6322 static void perf_output_read(struct perf_output_handle *handle, 6323 struct perf_event *event) 6324 { 6325 u64 enabled = 0, running = 0, now; 6326 u64 read_format = event->attr.read_format; 6327 6328 /* 6329 * compute total_time_enabled, total_time_running 6330 * based on snapshot values taken when the event 6331 * was last scheduled in. 6332 * 6333 * we cannot simply called update_context_time() 6334 * because of locking issue as we are called in 6335 * NMI context 6336 */ 6337 if (read_format & PERF_FORMAT_TOTAL_TIMES) 6338 calc_timer_values(event, &now, &enabled, &running); 6339 6340 if (event->attr.read_format & PERF_FORMAT_GROUP) 6341 perf_output_read_group(handle, event, enabled, running); 6342 else 6343 perf_output_read_one(handle, event, enabled, running); 6344 } 6345 6346 void perf_output_sample(struct perf_output_handle *handle, 6347 struct perf_event_header *header, 6348 struct perf_sample_data *data, 6349 struct perf_event *event) 6350 { 6351 u64 sample_type = data->type; 6352 6353 perf_output_put(handle, *header); 6354 6355 if (sample_type & PERF_SAMPLE_IDENTIFIER) 6356 perf_output_put(handle, data->id); 6357 6358 if (sample_type & PERF_SAMPLE_IP) 6359 perf_output_put(handle, data->ip); 6360 6361 if (sample_type & PERF_SAMPLE_TID) 6362 perf_output_put(handle, data->tid_entry); 6363 6364 if (sample_type & PERF_SAMPLE_TIME) 6365 perf_output_put(handle, data->time); 6366 6367 if (sample_type & PERF_SAMPLE_ADDR) 6368 perf_output_put(handle, data->addr); 6369 6370 if (sample_type & PERF_SAMPLE_ID) 6371 perf_output_put(handle, data->id); 6372 6373 if (sample_type & PERF_SAMPLE_STREAM_ID) 6374 perf_output_put(handle, data->stream_id); 6375 6376 if (sample_type & PERF_SAMPLE_CPU) 6377 perf_output_put(handle, data->cpu_entry); 6378 6379 if (sample_type & PERF_SAMPLE_PERIOD) 6380 perf_output_put(handle, data->period); 6381 6382 if (sample_type & PERF_SAMPLE_READ) 6383 perf_output_read(handle, event); 6384 6385 if (sample_type & PERF_SAMPLE_CALLCHAIN) { 6386 int size = 1; 6387 6388 size += data->callchain->nr; 6389 size *= sizeof(u64); 6390 __output_copy(handle, data->callchain, size); 6391 } 6392 6393 if (sample_type & PERF_SAMPLE_RAW) { 6394 struct perf_raw_record *raw = data->raw; 6395 6396 if (raw) { 6397 struct perf_raw_frag *frag = &raw->frag; 6398 6399 perf_output_put(handle, raw->size); 6400 do { 6401 if (frag->copy) { 6402 __output_custom(handle, frag->copy, 6403 frag->data, frag->size); 6404 } else { 6405 __output_copy(handle, frag->data, 6406 frag->size); 6407 } 6408 if (perf_raw_frag_last(frag)) 6409 break; 6410 frag = frag->next; 6411 } while (1); 6412 if (frag->pad) 6413 __output_skip(handle, NULL, frag->pad); 6414 } else { 6415 struct { 6416 u32 size; 6417 u32 data; 6418 } raw = { 6419 .size = sizeof(u32), 6420 .data = 0, 6421 }; 6422 perf_output_put(handle, raw); 6423 } 6424 } 6425 6426 if (sample_type & PERF_SAMPLE_BRANCH_STACK) { 6427 if (data->br_stack) { 6428 size_t size; 6429 6430 size = data->br_stack->nr 6431 * sizeof(struct perf_branch_entry); 6432 6433 perf_output_put(handle, data->br_stack->nr); 6434 perf_output_copy(handle, data->br_stack->entries, size); 6435 } else { 6436 /* 6437 * we always store at least the value of nr 6438 */ 6439 u64 nr = 0; 6440 perf_output_put(handle, nr); 6441 } 6442 } 6443 6444 if (sample_type & PERF_SAMPLE_REGS_USER) { 6445 u64 abi = data->regs_user.abi; 6446 6447 /* 6448 * If there are no regs to dump, notice it through 6449 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). 6450 */ 6451 perf_output_put(handle, abi); 6452 6453 if (abi) { 6454 u64 mask = event->attr.sample_regs_user; 6455 perf_output_sample_regs(handle, 6456 data->regs_user.regs, 6457 mask); 6458 } 6459 } 6460 6461 if (sample_type & PERF_SAMPLE_STACK_USER) { 6462 perf_output_sample_ustack(handle, 6463 data->stack_user_size, 6464 data->regs_user.regs); 6465 } 6466 6467 if (sample_type & PERF_SAMPLE_WEIGHT) 6468 perf_output_put(handle, data->weight); 6469 6470 if (sample_type & PERF_SAMPLE_DATA_SRC) 6471 perf_output_put(handle, data->data_src.val); 6472 6473 if (sample_type & PERF_SAMPLE_TRANSACTION) 6474 perf_output_put(handle, data->txn); 6475 6476 if (sample_type & PERF_SAMPLE_REGS_INTR) { 6477 u64 abi = data->regs_intr.abi; 6478 /* 6479 * If there are no regs to dump, notice it through 6480 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). 6481 */ 6482 perf_output_put(handle, abi); 6483 6484 if (abi) { 6485 u64 mask = event->attr.sample_regs_intr; 6486 6487 perf_output_sample_regs(handle, 6488 data->regs_intr.regs, 6489 mask); 6490 } 6491 } 6492 6493 if (sample_type & PERF_SAMPLE_PHYS_ADDR) 6494 perf_output_put(handle, data->phys_addr); 6495 6496 if (!event->attr.watermark) { 6497 int wakeup_events = event->attr.wakeup_events; 6498 6499 if (wakeup_events) { 6500 struct ring_buffer *rb = handle->rb; 6501 int events = local_inc_return(&rb->events); 6502 6503 if (events >= wakeup_events) { 6504 local_sub(wakeup_events, &rb->events); 6505 local_inc(&rb->wakeup); 6506 } 6507 } 6508 } 6509 } 6510 6511 static u64 perf_virt_to_phys(u64 virt) 6512 { 6513 u64 phys_addr = 0; 6514 struct page *p = NULL; 6515 6516 if (!virt) 6517 return 0; 6518 6519 if (virt >= TASK_SIZE) { 6520 /* If it's vmalloc()d memory, leave phys_addr as 0 */ 6521 if (virt_addr_valid((void *)(uintptr_t)virt) && 6522 !(virt >= VMALLOC_START && virt < VMALLOC_END)) 6523 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt); 6524 } else { 6525 /* 6526 * Walking the pages tables for user address. 6527 * Interrupts are disabled, so it prevents any tear down 6528 * of the page tables. 6529 * Try IRQ-safe __get_user_pages_fast first. 6530 * If failed, leave phys_addr as 0. 6531 */ 6532 if ((current->mm != NULL) && 6533 (__get_user_pages_fast(virt, 1, 0, &p) == 1)) 6534 phys_addr = page_to_phys(p) + virt % PAGE_SIZE; 6535 6536 if (p) 6537 put_page(p); 6538 } 6539 6540 return phys_addr; 6541 } 6542 6543 static struct perf_callchain_entry __empty_callchain = { .nr = 0, }; 6544 6545 struct perf_callchain_entry * 6546 perf_callchain(struct perf_event *event, struct pt_regs *regs) 6547 { 6548 bool kernel = !event->attr.exclude_callchain_kernel; 6549 bool user = !event->attr.exclude_callchain_user; 6550 /* Disallow cross-task user callchains. */ 6551 bool crosstask = event->ctx->task && event->ctx->task != current; 6552 const u32 max_stack = event->attr.sample_max_stack; 6553 struct perf_callchain_entry *callchain; 6554 6555 if (!kernel && !user) 6556 return &__empty_callchain; 6557 6558 callchain = get_perf_callchain(regs, 0, kernel, user, 6559 max_stack, crosstask, true); 6560 return callchain ?: &__empty_callchain; 6561 } 6562 6563 void perf_prepare_sample(struct perf_event_header *header, 6564 struct perf_sample_data *data, 6565 struct perf_event *event, 6566 struct pt_regs *regs) 6567 { 6568 u64 sample_type = event->attr.sample_type; 6569 6570 header->type = PERF_RECORD_SAMPLE; 6571 header->size = sizeof(*header) + event->header_size; 6572 6573 header->misc = 0; 6574 header->misc |= perf_misc_flags(regs); 6575 6576 __perf_event_header__init_id(header, data, event); 6577 6578 if (sample_type & PERF_SAMPLE_IP) 6579 data->ip = perf_instruction_pointer(regs); 6580 6581 if (sample_type & PERF_SAMPLE_CALLCHAIN) { 6582 int size = 1; 6583 6584 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY)) 6585 data->callchain = perf_callchain(event, regs); 6586 6587 size += data->callchain->nr; 6588 6589 header->size += size * sizeof(u64); 6590 } 6591 6592 if (sample_type & PERF_SAMPLE_RAW) { 6593 struct perf_raw_record *raw = data->raw; 6594 int size; 6595 6596 if (raw) { 6597 struct perf_raw_frag *frag = &raw->frag; 6598 u32 sum = 0; 6599 6600 do { 6601 sum += frag->size; 6602 if (perf_raw_frag_last(frag)) 6603 break; 6604 frag = frag->next; 6605 } while (1); 6606 6607 size = round_up(sum + sizeof(u32), sizeof(u64)); 6608 raw->size = size - sizeof(u32); 6609 frag->pad = raw->size - sum; 6610 } else { 6611 size = sizeof(u64); 6612 } 6613 6614 header->size += size; 6615 } 6616 6617 if (sample_type & PERF_SAMPLE_BRANCH_STACK) { 6618 int size = sizeof(u64); /* nr */ 6619 if (data->br_stack) { 6620 size += data->br_stack->nr 6621 * sizeof(struct perf_branch_entry); 6622 } 6623 header->size += size; 6624 } 6625 6626 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER)) 6627 perf_sample_regs_user(&data->regs_user, regs, 6628 &data->regs_user_copy); 6629 6630 if (sample_type & PERF_SAMPLE_REGS_USER) { 6631 /* regs dump ABI info */ 6632 int size = sizeof(u64); 6633 6634 if (data->regs_user.regs) { 6635 u64 mask = event->attr.sample_regs_user; 6636 size += hweight64(mask) * sizeof(u64); 6637 } 6638 6639 header->size += size; 6640 } 6641 6642 if (sample_type & PERF_SAMPLE_STACK_USER) { 6643 /* 6644 * Either we need PERF_SAMPLE_STACK_USER bit to be always 6645 * processed as the last one or have additional check added 6646 * in case new sample type is added, because we could eat 6647 * up the rest of the sample size. 6648 */ 6649 u16 stack_size = event->attr.sample_stack_user; 6650 u16 size = sizeof(u64); 6651 6652 stack_size = perf_sample_ustack_size(stack_size, header->size, 6653 data->regs_user.regs); 6654 6655 /* 6656 * If there is something to dump, add space for the dump 6657 * itself and for the field that tells the dynamic size, 6658 * which is how many have been actually dumped. 6659 */ 6660 if (stack_size) 6661 size += sizeof(u64) + stack_size; 6662 6663 data->stack_user_size = stack_size; 6664 header->size += size; 6665 } 6666 6667 if (sample_type & PERF_SAMPLE_REGS_INTR) { 6668 /* regs dump ABI info */ 6669 int size = sizeof(u64); 6670 6671 perf_sample_regs_intr(&data->regs_intr, regs); 6672 6673 if (data->regs_intr.regs) { 6674 u64 mask = event->attr.sample_regs_intr; 6675 6676 size += hweight64(mask) * sizeof(u64); 6677 } 6678 6679 header->size += size; 6680 } 6681 6682 if (sample_type & PERF_SAMPLE_PHYS_ADDR) 6683 data->phys_addr = perf_virt_to_phys(data->addr); 6684 } 6685 6686 static __always_inline int 6687 __perf_event_output(struct perf_event *event, 6688 struct perf_sample_data *data, 6689 struct pt_regs *regs, 6690 int (*output_begin)(struct perf_output_handle *, 6691 struct perf_event *, 6692 unsigned int)) 6693 { 6694 struct perf_output_handle handle; 6695 struct perf_event_header header; 6696 int err; 6697 6698 /* protect the callchain buffers */ 6699 rcu_read_lock(); 6700 6701 perf_prepare_sample(&header, data, event, regs); 6702 6703 err = output_begin(&handle, event, header.size); 6704 if (err) 6705 goto exit; 6706 6707 perf_output_sample(&handle, &header, data, event); 6708 6709 perf_output_end(&handle); 6710 6711 exit: 6712 rcu_read_unlock(); 6713 return err; 6714 } 6715 6716 void 6717 perf_event_output_forward(struct perf_event *event, 6718 struct perf_sample_data *data, 6719 struct pt_regs *regs) 6720 { 6721 __perf_event_output(event, data, regs, perf_output_begin_forward); 6722 } 6723 6724 void 6725 perf_event_output_backward(struct perf_event *event, 6726 struct perf_sample_data *data, 6727 struct pt_regs *regs) 6728 { 6729 __perf_event_output(event, data, regs, perf_output_begin_backward); 6730 } 6731 6732 int 6733 perf_event_output(struct perf_event *event, 6734 struct perf_sample_data *data, 6735 struct pt_regs *regs) 6736 { 6737 return __perf_event_output(event, data, regs, perf_output_begin); 6738 } 6739 6740 /* 6741 * read event_id 6742 */ 6743 6744 struct perf_read_event { 6745 struct perf_event_header header; 6746 6747 u32 pid; 6748 u32 tid; 6749 }; 6750 6751 static void 6752 perf_event_read_event(struct perf_event *event, 6753 struct task_struct *task) 6754 { 6755 struct perf_output_handle handle; 6756 struct perf_sample_data sample; 6757 struct perf_read_event read_event = { 6758 .header = { 6759 .type = PERF_RECORD_READ, 6760 .misc = 0, 6761 .size = sizeof(read_event) + event->read_size, 6762 }, 6763 .pid = perf_event_pid(event, task), 6764 .tid = perf_event_tid(event, task), 6765 }; 6766 int ret; 6767 6768 perf_event_header__init_id(&read_event.header, &sample, event); 6769 ret = perf_output_begin(&handle, event, read_event.header.size); 6770 if (ret) 6771 return; 6772 6773 perf_output_put(&handle, read_event); 6774 perf_output_read(&handle, event); 6775 perf_event__output_id_sample(event, &handle, &sample); 6776 6777 perf_output_end(&handle); 6778 } 6779 6780 typedef void (perf_iterate_f)(struct perf_event *event, void *data); 6781 6782 static void 6783 perf_iterate_ctx(struct perf_event_context *ctx, 6784 perf_iterate_f output, 6785 void *data, bool all) 6786 { 6787 struct perf_event *event; 6788 6789 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 6790 if (!all) { 6791 if (event->state < PERF_EVENT_STATE_INACTIVE) 6792 continue; 6793 if (!event_filter_match(event)) 6794 continue; 6795 } 6796 6797 output(event, data); 6798 } 6799 } 6800 6801 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data) 6802 { 6803 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events); 6804 struct perf_event *event; 6805 6806 list_for_each_entry_rcu(event, &pel->list, sb_list) { 6807 /* 6808 * Skip events that are not fully formed yet; ensure that 6809 * if we observe event->ctx, both event and ctx will be 6810 * complete enough. See perf_install_in_context(). 6811 */ 6812 if (!smp_load_acquire(&event->ctx)) 6813 continue; 6814 6815 if (event->state < PERF_EVENT_STATE_INACTIVE) 6816 continue; 6817 if (!event_filter_match(event)) 6818 continue; 6819 output(event, data); 6820 } 6821 } 6822 6823 /* 6824 * Iterate all events that need to receive side-band events. 6825 * 6826 * For new callers; ensure that account_pmu_sb_event() includes 6827 * your event, otherwise it might not get delivered. 6828 */ 6829 static void 6830 perf_iterate_sb(perf_iterate_f output, void *data, 6831 struct perf_event_context *task_ctx) 6832 { 6833 struct perf_event_context *ctx; 6834 int ctxn; 6835 6836 rcu_read_lock(); 6837 preempt_disable(); 6838 6839 /* 6840 * If we have task_ctx != NULL we only notify the task context itself. 6841 * The task_ctx is set only for EXIT events before releasing task 6842 * context. 6843 */ 6844 if (task_ctx) { 6845 perf_iterate_ctx(task_ctx, output, data, false); 6846 goto done; 6847 } 6848 6849 perf_iterate_sb_cpu(output, data); 6850 6851 for_each_task_context_nr(ctxn) { 6852 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); 6853 if (ctx) 6854 perf_iterate_ctx(ctx, output, data, false); 6855 } 6856 done: 6857 preempt_enable(); 6858 rcu_read_unlock(); 6859 } 6860 6861 /* 6862 * Clear all file-based filters at exec, they'll have to be 6863 * re-instated when/if these objects are mmapped again. 6864 */ 6865 static void perf_event_addr_filters_exec(struct perf_event *event, void *data) 6866 { 6867 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 6868 struct perf_addr_filter *filter; 6869 unsigned int restart = 0, count = 0; 6870 unsigned long flags; 6871 6872 if (!has_addr_filter(event)) 6873 return; 6874 6875 raw_spin_lock_irqsave(&ifh->lock, flags); 6876 list_for_each_entry(filter, &ifh->list, entry) { 6877 if (filter->path.dentry) { 6878 event->addr_filter_ranges[count].start = 0; 6879 event->addr_filter_ranges[count].size = 0; 6880 restart++; 6881 } 6882 6883 count++; 6884 } 6885 6886 if (restart) 6887 event->addr_filters_gen++; 6888 raw_spin_unlock_irqrestore(&ifh->lock, flags); 6889 6890 if (restart) 6891 perf_event_stop(event, 1); 6892 } 6893 6894 void perf_event_exec(void) 6895 { 6896 struct perf_event_context *ctx; 6897 int ctxn; 6898 6899 rcu_read_lock(); 6900 for_each_task_context_nr(ctxn) { 6901 ctx = current->perf_event_ctxp[ctxn]; 6902 if (!ctx) 6903 continue; 6904 6905 perf_event_enable_on_exec(ctxn); 6906 6907 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL, 6908 true); 6909 } 6910 rcu_read_unlock(); 6911 } 6912 6913 struct remote_output { 6914 struct ring_buffer *rb; 6915 int err; 6916 }; 6917 6918 static void __perf_event_output_stop(struct perf_event *event, void *data) 6919 { 6920 struct perf_event *parent = event->parent; 6921 struct remote_output *ro = data; 6922 struct ring_buffer *rb = ro->rb; 6923 struct stop_event_data sd = { 6924 .event = event, 6925 }; 6926 6927 if (!has_aux(event)) 6928 return; 6929 6930 if (!parent) 6931 parent = event; 6932 6933 /* 6934 * In case of inheritance, it will be the parent that links to the 6935 * ring-buffer, but it will be the child that's actually using it. 6936 * 6937 * We are using event::rb to determine if the event should be stopped, 6938 * however this may race with ring_buffer_attach() (through set_output), 6939 * which will make us skip the event that actually needs to be stopped. 6940 * So ring_buffer_attach() has to stop an aux event before re-assigning 6941 * its rb pointer. 6942 */ 6943 if (rcu_dereference(parent->rb) == rb) 6944 ro->err = __perf_event_stop(&sd); 6945 } 6946 6947 static int __perf_pmu_output_stop(void *info) 6948 { 6949 struct perf_event *event = info; 6950 struct pmu *pmu = event->pmu; 6951 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 6952 struct remote_output ro = { 6953 .rb = event->rb, 6954 }; 6955 6956 rcu_read_lock(); 6957 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false); 6958 if (cpuctx->task_ctx) 6959 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop, 6960 &ro, false); 6961 rcu_read_unlock(); 6962 6963 return ro.err; 6964 } 6965 6966 static void perf_pmu_output_stop(struct perf_event *event) 6967 { 6968 struct perf_event *iter; 6969 int err, cpu; 6970 6971 restart: 6972 rcu_read_lock(); 6973 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) { 6974 /* 6975 * For per-CPU events, we need to make sure that neither they 6976 * nor their children are running; for cpu==-1 events it's 6977 * sufficient to stop the event itself if it's active, since 6978 * it can't have children. 6979 */ 6980 cpu = iter->cpu; 6981 if (cpu == -1) 6982 cpu = READ_ONCE(iter->oncpu); 6983 6984 if (cpu == -1) 6985 continue; 6986 6987 err = cpu_function_call(cpu, __perf_pmu_output_stop, event); 6988 if (err == -EAGAIN) { 6989 rcu_read_unlock(); 6990 goto restart; 6991 } 6992 } 6993 rcu_read_unlock(); 6994 } 6995 6996 /* 6997 * task tracking -- fork/exit 6998 * 6999 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task 7000 */ 7001 7002 struct perf_task_event { 7003 struct task_struct *task; 7004 struct perf_event_context *task_ctx; 7005 7006 struct { 7007 struct perf_event_header header; 7008 7009 u32 pid; 7010 u32 ppid; 7011 u32 tid; 7012 u32 ptid; 7013 u64 time; 7014 } event_id; 7015 }; 7016 7017 static int perf_event_task_match(struct perf_event *event) 7018 { 7019 return event->attr.comm || event->attr.mmap || 7020 event->attr.mmap2 || event->attr.mmap_data || 7021 event->attr.task; 7022 } 7023 7024 static void perf_event_task_output(struct perf_event *event, 7025 void *data) 7026 { 7027 struct perf_task_event *task_event = data; 7028 struct perf_output_handle handle; 7029 struct perf_sample_data sample; 7030 struct task_struct *task = task_event->task; 7031 int ret, size = task_event->event_id.header.size; 7032 7033 if (!perf_event_task_match(event)) 7034 return; 7035 7036 perf_event_header__init_id(&task_event->event_id.header, &sample, event); 7037 7038 ret = perf_output_begin(&handle, event, 7039 task_event->event_id.header.size); 7040 if (ret) 7041 goto out; 7042 7043 task_event->event_id.pid = perf_event_pid(event, task); 7044 task_event->event_id.ppid = perf_event_pid(event, current); 7045 7046 task_event->event_id.tid = perf_event_tid(event, task); 7047 task_event->event_id.ptid = perf_event_tid(event, current); 7048 7049 task_event->event_id.time = perf_event_clock(event); 7050 7051 perf_output_put(&handle, task_event->event_id); 7052 7053 perf_event__output_id_sample(event, &handle, &sample); 7054 7055 perf_output_end(&handle); 7056 out: 7057 task_event->event_id.header.size = size; 7058 } 7059 7060 static void perf_event_task(struct task_struct *task, 7061 struct perf_event_context *task_ctx, 7062 int new) 7063 { 7064 struct perf_task_event task_event; 7065 7066 if (!atomic_read(&nr_comm_events) && 7067 !atomic_read(&nr_mmap_events) && 7068 !atomic_read(&nr_task_events)) 7069 return; 7070 7071 task_event = (struct perf_task_event){ 7072 .task = task, 7073 .task_ctx = task_ctx, 7074 .event_id = { 7075 .header = { 7076 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT, 7077 .misc = 0, 7078 .size = sizeof(task_event.event_id), 7079 }, 7080 /* .pid */ 7081 /* .ppid */ 7082 /* .tid */ 7083 /* .ptid */ 7084 /* .time */ 7085 }, 7086 }; 7087 7088 perf_iterate_sb(perf_event_task_output, 7089 &task_event, 7090 task_ctx); 7091 } 7092 7093 void perf_event_fork(struct task_struct *task) 7094 { 7095 perf_event_task(task, NULL, 1); 7096 perf_event_namespaces(task); 7097 } 7098 7099 /* 7100 * comm tracking 7101 */ 7102 7103 struct perf_comm_event { 7104 struct task_struct *task; 7105 char *comm; 7106 int comm_size; 7107 7108 struct { 7109 struct perf_event_header header; 7110 7111 u32 pid; 7112 u32 tid; 7113 } event_id; 7114 }; 7115 7116 static int perf_event_comm_match(struct perf_event *event) 7117 { 7118 return event->attr.comm; 7119 } 7120 7121 static void perf_event_comm_output(struct perf_event *event, 7122 void *data) 7123 { 7124 struct perf_comm_event *comm_event = data; 7125 struct perf_output_handle handle; 7126 struct perf_sample_data sample; 7127 int size = comm_event->event_id.header.size; 7128 int ret; 7129 7130 if (!perf_event_comm_match(event)) 7131 return; 7132 7133 perf_event_header__init_id(&comm_event->event_id.header, &sample, event); 7134 ret = perf_output_begin(&handle, event, 7135 comm_event->event_id.header.size); 7136 7137 if (ret) 7138 goto out; 7139 7140 comm_event->event_id.pid = perf_event_pid(event, comm_event->task); 7141 comm_event->event_id.tid = perf_event_tid(event, comm_event->task); 7142 7143 perf_output_put(&handle, comm_event->event_id); 7144 __output_copy(&handle, comm_event->comm, 7145 comm_event->comm_size); 7146 7147 perf_event__output_id_sample(event, &handle, &sample); 7148 7149 perf_output_end(&handle); 7150 out: 7151 comm_event->event_id.header.size = size; 7152 } 7153 7154 static void perf_event_comm_event(struct perf_comm_event *comm_event) 7155 { 7156 char comm[TASK_COMM_LEN]; 7157 unsigned int size; 7158 7159 memset(comm, 0, sizeof(comm)); 7160 strlcpy(comm, comm_event->task->comm, sizeof(comm)); 7161 size = ALIGN(strlen(comm)+1, sizeof(u64)); 7162 7163 comm_event->comm = comm; 7164 comm_event->comm_size = size; 7165 7166 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size; 7167 7168 perf_iterate_sb(perf_event_comm_output, 7169 comm_event, 7170 NULL); 7171 } 7172 7173 void perf_event_comm(struct task_struct *task, bool exec) 7174 { 7175 struct perf_comm_event comm_event; 7176 7177 if (!atomic_read(&nr_comm_events)) 7178 return; 7179 7180 comm_event = (struct perf_comm_event){ 7181 .task = task, 7182 /* .comm */ 7183 /* .comm_size */ 7184 .event_id = { 7185 .header = { 7186 .type = PERF_RECORD_COMM, 7187 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0, 7188 /* .size */ 7189 }, 7190 /* .pid */ 7191 /* .tid */ 7192 }, 7193 }; 7194 7195 perf_event_comm_event(&comm_event); 7196 } 7197 7198 /* 7199 * namespaces tracking 7200 */ 7201 7202 struct perf_namespaces_event { 7203 struct task_struct *task; 7204 7205 struct { 7206 struct perf_event_header header; 7207 7208 u32 pid; 7209 u32 tid; 7210 u64 nr_namespaces; 7211 struct perf_ns_link_info link_info[NR_NAMESPACES]; 7212 } event_id; 7213 }; 7214 7215 static int perf_event_namespaces_match(struct perf_event *event) 7216 { 7217 return event->attr.namespaces; 7218 } 7219 7220 static void perf_event_namespaces_output(struct perf_event *event, 7221 void *data) 7222 { 7223 struct perf_namespaces_event *namespaces_event = data; 7224 struct perf_output_handle handle; 7225 struct perf_sample_data sample; 7226 u16 header_size = namespaces_event->event_id.header.size; 7227 int ret; 7228 7229 if (!perf_event_namespaces_match(event)) 7230 return; 7231 7232 perf_event_header__init_id(&namespaces_event->event_id.header, 7233 &sample, event); 7234 ret = perf_output_begin(&handle, event, 7235 namespaces_event->event_id.header.size); 7236 if (ret) 7237 goto out; 7238 7239 namespaces_event->event_id.pid = perf_event_pid(event, 7240 namespaces_event->task); 7241 namespaces_event->event_id.tid = perf_event_tid(event, 7242 namespaces_event->task); 7243 7244 perf_output_put(&handle, namespaces_event->event_id); 7245 7246 perf_event__output_id_sample(event, &handle, &sample); 7247 7248 perf_output_end(&handle); 7249 out: 7250 namespaces_event->event_id.header.size = header_size; 7251 } 7252 7253 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info, 7254 struct task_struct *task, 7255 const struct proc_ns_operations *ns_ops) 7256 { 7257 struct path ns_path; 7258 struct inode *ns_inode; 7259 void *error; 7260 7261 error = ns_get_path(&ns_path, task, ns_ops); 7262 if (!error) { 7263 ns_inode = ns_path.dentry->d_inode; 7264 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev); 7265 ns_link_info->ino = ns_inode->i_ino; 7266 path_put(&ns_path); 7267 } 7268 } 7269 7270 void perf_event_namespaces(struct task_struct *task) 7271 { 7272 struct perf_namespaces_event namespaces_event; 7273 struct perf_ns_link_info *ns_link_info; 7274 7275 if (!atomic_read(&nr_namespaces_events)) 7276 return; 7277 7278 namespaces_event = (struct perf_namespaces_event){ 7279 .task = task, 7280 .event_id = { 7281 .header = { 7282 .type = PERF_RECORD_NAMESPACES, 7283 .misc = 0, 7284 .size = sizeof(namespaces_event.event_id), 7285 }, 7286 /* .pid */ 7287 /* .tid */ 7288 .nr_namespaces = NR_NAMESPACES, 7289 /* .link_info[NR_NAMESPACES] */ 7290 }, 7291 }; 7292 7293 ns_link_info = namespaces_event.event_id.link_info; 7294 7295 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX], 7296 task, &mntns_operations); 7297 7298 #ifdef CONFIG_USER_NS 7299 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX], 7300 task, &userns_operations); 7301 #endif 7302 #ifdef CONFIG_NET_NS 7303 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX], 7304 task, &netns_operations); 7305 #endif 7306 #ifdef CONFIG_UTS_NS 7307 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX], 7308 task, &utsns_operations); 7309 #endif 7310 #ifdef CONFIG_IPC_NS 7311 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX], 7312 task, &ipcns_operations); 7313 #endif 7314 #ifdef CONFIG_PID_NS 7315 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX], 7316 task, &pidns_operations); 7317 #endif 7318 #ifdef CONFIG_CGROUPS 7319 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX], 7320 task, &cgroupns_operations); 7321 #endif 7322 7323 perf_iterate_sb(perf_event_namespaces_output, 7324 &namespaces_event, 7325 NULL); 7326 } 7327 7328 /* 7329 * mmap tracking 7330 */ 7331 7332 struct perf_mmap_event { 7333 struct vm_area_struct *vma; 7334 7335 const char *file_name; 7336 int file_size; 7337 int maj, min; 7338 u64 ino; 7339 u64 ino_generation; 7340 u32 prot, flags; 7341 7342 struct { 7343 struct perf_event_header header; 7344 7345 u32 pid; 7346 u32 tid; 7347 u64 start; 7348 u64 len; 7349 u64 pgoff; 7350 } event_id; 7351 }; 7352 7353 static int perf_event_mmap_match(struct perf_event *event, 7354 void *data) 7355 { 7356 struct perf_mmap_event *mmap_event = data; 7357 struct vm_area_struct *vma = mmap_event->vma; 7358 int executable = vma->vm_flags & VM_EXEC; 7359 7360 return (!executable && event->attr.mmap_data) || 7361 (executable && (event->attr.mmap || event->attr.mmap2)); 7362 } 7363 7364 static void perf_event_mmap_output(struct perf_event *event, 7365 void *data) 7366 { 7367 struct perf_mmap_event *mmap_event = data; 7368 struct perf_output_handle handle; 7369 struct perf_sample_data sample; 7370 int size = mmap_event->event_id.header.size; 7371 u32 type = mmap_event->event_id.header.type; 7372 int ret; 7373 7374 if (!perf_event_mmap_match(event, data)) 7375 return; 7376 7377 if (event->attr.mmap2) { 7378 mmap_event->event_id.header.type = PERF_RECORD_MMAP2; 7379 mmap_event->event_id.header.size += sizeof(mmap_event->maj); 7380 mmap_event->event_id.header.size += sizeof(mmap_event->min); 7381 mmap_event->event_id.header.size += sizeof(mmap_event->ino); 7382 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation); 7383 mmap_event->event_id.header.size += sizeof(mmap_event->prot); 7384 mmap_event->event_id.header.size += sizeof(mmap_event->flags); 7385 } 7386 7387 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event); 7388 ret = perf_output_begin(&handle, event, 7389 mmap_event->event_id.header.size); 7390 if (ret) 7391 goto out; 7392 7393 mmap_event->event_id.pid = perf_event_pid(event, current); 7394 mmap_event->event_id.tid = perf_event_tid(event, current); 7395 7396 perf_output_put(&handle, mmap_event->event_id); 7397 7398 if (event->attr.mmap2) { 7399 perf_output_put(&handle, mmap_event->maj); 7400 perf_output_put(&handle, mmap_event->min); 7401 perf_output_put(&handle, mmap_event->ino); 7402 perf_output_put(&handle, mmap_event->ino_generation); 7403 perf_output_put(&handle, mmap_event->prot); 7404 perf_output_put(&handle, mmap_event->flags); 7405 } 7406 7407 __output_copy(&handle, mmap_event->file_name, 7408 mmap_event->file_size); 7409 7410 perf_event__output_id_sample(event, &handle, &sample); 7411 7412 perf_output_end(&handle); 7413 out: 7414 mmap_event->event_id.header.size = size; 7415 mmap_event->event_id.header.type = type; 7416 } 7417 7418 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) 7419 { 7420 struct vm_area_struct *vma = mmap_event->vma; 7421 struct file *file = vma->vm_file; 7422 int maj = 0, min = 0; 7423 u64 ino = 0, gen = 0; 7424 u32 prot = 0, flags = 0; 7425 unsigned int size; 7426 char tmp[16]; 7427 char *buf = NULL; 7428 char *name; 7429 7430 if (vma->vm_flags & VM_READ) 7431 prot |= PROT_READ; 7432 if (vma->vm_flags & VM_WRITE) 7433 prot |= PROT_WRITE; 7434 if (vma->vm_flags & VM_EXEC) 7435 prot |= PROT_EXEC; 7436 7437 if (vma->vm_flags & VM_MAYSHARE) 7438 flags = MAP_SHARED; 7439 else 7440 flags = MAP_PRIVATE; 7441 7442 if (vma->vm_flags & VM_DENYWRITE) 7443 flags |= MAP_DENYWRITE; 7444 if (vma->vm_flags & VM_MAYEXEC) 7445 flags |= MAP_EXECUTABLE; 7446 if (vma->vm_flags & VM_LOCKED) 7447 flags |= MAP_LOCKED; 7448 if (vma->vm_flags & VM_HUGETLB) 7449 flags |= MAP_HUGETLB; 7450 7451 if (file) { 7452 struct inode *inode; 7453 dev_t dev; 7454 7455 buf = kmalloc(PATH_MAX, GFP_KERNEL); 7456 if (!buf) { 7457 name = "//enomem"; 7458 goto cpy_name; 7459 } 7460 /* 7461 * d_path() works from the end of the rb backwards, so we 7462 * need to add enough zero bytes after the string to handle 7463 * the 64bit alignment we do later. 7464 */ 7465 name = file_path(file, buf, PATH_MAX - sizeof(u64)); 7466 if (IS_ERR(name)) { 7467 name = "//toolong"; 7468 goto cpy_name; 7469 } 7470 inode = file_inode(vma->vm_file); 7471 dev = inode->i_sb->s_dev; 7472 ino = inode->i_ino; 7473 gen = inode->i_generation; 7474 maj = MAJOR(dev); 7475 min = MINOR(dev); 7476 7477 goto got_name; 7478 } else { 7479 if (vma->vm_ops && vma->vm_ops->name) { 7480 name = (char *) vma->vm_ops->name(vma); 7481 if (name) 7482 goto cpy_name; 7483 } 7484 7485 name = (char *)arch_vma_name(vma); 7486 if (name) 7487 goto cpy_name; 7488 7489 if (vma->vm_start <= vma->vm_mm->start_brk && 7490 vma->vm_end >= vma->vm_mm->brk) { 7491 name = "[heap]"; 7492 goto cpy_name; 7493 } 7494 if (vma->vm_start <= vma->vm_mm->start_stack && 7495 vma->vm_end >= vma->vm_mm->start_stack) { 7496 name = "[stack]"; 7497 goto cpy_name; 7498 } 7499 7500 name = "//anon"; 7501 goto cpy_name; 7502 } 7503 7504 cpy_name: 7505 strlcpy(tmp, name, sizeof(tmp)); 7506 name = tmp; 7507 got_name: 7508 /* 7509 * Since our buffer works in 8 byte units we need to align our string 7510 * size to a multiple of 8. However, we must guarantee the tail end is 7511 * zero'd out to avoid leaking random bits to userspace. 7512 */ 7513 size = strlen(name)+1; 7514 while (!IS_ALIGNED(size, sizeof(u64))) 7515 name[size++] = '\0'; 7516 7517 mmap_event->file_name = name; 7518 mmap_event->file_size = size; 7519 mmap_event->maj = maj; 7520 mmap_event->min = min; 7521 mmap_event->ino = ino; 7522 mmap_event->ino_generation = gen; 7523 mmap_event->prot = prot; 7524 mmap_event->flags = flags; 7525 7526 if (!(vma->vm_flags & VM_EXEC)) 7527 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA; 7528 7529 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size; 7530 7531 perf_iterate_sb(perf_event_mmap_output, 7532 mmap_event, 7533 NULL); 7534 7535 kfree(buf); 7536 } 7537 7538 /* 7539 * Check whether inode and address range match filter criteria. 7540 */ 7541 static bool perf_addr_filter_match(struct perf_addr_filter *filter, 7542 struct file *file, unsigned long offset, 7543 unsigned long size) 7544 { 7545 /* d_inode(NULL) won't be equal to any mapped user-space file */ 7546 if (!filter->path.dentry) 7547 return false; 7548 7549 if (d_inode(filter->path.dentry) != file_inode(file)) 7550 return false; 7551 7552 if (filter->offset > offset + size) 7553 return false; 7554 7555 if (filter->offset + filter->size < offset) 7556 return false; 7557 7558 return true; 7559 } 7560 7561 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter, 7562 struct vm_area_struct *vma, 7563 struct perf_addr_filter_range *fr) 7564 { 7565 unsigned long vma_size = vma->vm_end - vma->vm_start; 7566 unsigned long off = vma->vm_pgoff << PAGE_SHIFT; 7567 struct file *file = vma->vm_file; 7568 7569 if (!perf_addr_filter_match(filter, file, off, vma_size)) 7570 return false; 7571 7572 if (filter->offset < off) { 7573 fr->start = vma->vm_start; 7574 fr->size = min(vma_size, filter->size - (off - filter->offset)); 7575 } else { 7576 fr->start = vma->vm_start + filter->offset - off; 7577 fr->size = min(vma->vm_end - fr->start, filter->size); 7578 } 7579 7580 return true; 7581 } 7582 7583 static void __perf_addr_filters_adjust(struct perf_event *event, void *data) 7584 { 7585 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 7586 struct vm_area_struct *vma = data; 7587 struct perf_addr_filter *filter; 7588 unsigned int restart = 0, count = 0; 7589 unsigned long flags; 7590 7591 if (!has_addr_filter(event)) 7592 return; 7593 7594 if (!vma->vm_file) 7595 return; 7596 7597 raw_spin_lock_irqsave(&ifh->lock, flags); 7598 list_for_each_entry(filter, &ifh->list, entry) { 7599 if (perf_addr_filter_vma_adjust(filter, vma, 7600 &event->addr_filter_ranges[count])) 7601 restart++; 7602 7603 count++; 7604 } 7605 7606 if (restart) 7607 event->addr_filters_gen++; 7608 raw_spin_unlock_irqrestore(&ifh->lock, flags); 7609 7610 if (restart) 7611 perf_event_stop(event, 1); 7612 } 7613 7614 /* 7615 * Adjust all task's events' filters to the new vma 7616 */ 7617 static void perf_addr_filters_adjust(struct vm_area_struct *vma) 7618 { 7619 struct perf_event_context *ctx; 7620 int ctxn; 7621 7622 /* 7623 * Data tracing isn't supported yet and as such there is no need 7624 * to keep track of anything that isn't related to executable code: 7625 */ 7626 if (!(vma->vm_flags & VM_EXEC)) 7627 return; 7628 7629 rcu_read_lock(); 7630 for_each_task_context_nr(ctxn) { 7631 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); 7632 if (!ctx) 7633 continue; 7634 7635 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true); 7636 } 7637 rcu_read_unlock(); 7638 } 7639 7640 void perf_event_mmap(struct vm_area_struct *vma) 7641 { 7642 struct perf_mmap_event mmap_event; 7643 7644 if (!atomic_read(&nr_mmap_events)) 7645 return; 7646 7647 mmap_event = (struct perf_mmap_event){ 7648 .vma = vma, 7649 /* .file_name */ 7650 /* .file_size */ 7651 .event_id = { 7652 .header = { 7653 .type = PERF_RECORD_MMAP, 7654 .misc = PERF_RECORD_MISC_USER, 7655 /* .size */ 7656 }, 7657 /* .pid */ 7658 /* .tid */ 7659 .start = vma->vm_start, 7660 .len = vma->vm_end - vma->vm_start, 7661 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT, 7662 }, 7663 /* .maj (attr_mmap2 only) */ 7664 /* .min (attr_mmap2 only) */ 7665 /* .ino (attr_mmap2 only) */ 7666 /* .ino_generation (attr_mmap2 only) */ 7667 /* .prot (attr_mmap2 only) */ 7668 /* .flags (attr_mmap2 only) */ 7669 }; 7670 7671 perf_addr_filters_adjust(vma); 7672 perf_event_mmap_event(&mmap_event); 7673 } 7674 7675 void perf_event_aux_event(struct perf_event *event, unsigned long head, 7676 unsigned long size, u64 flags) 7677 { 7678 struct perf_output_handle handle; 7679 struct perf_sample_data sample; 7680 struct perf_aux_event { 7681 struct perf_event_header header; 7682 u64 offset; 7683 u64 size; 7684 u64 flags; 7685 } rec = { 7686 .header = { 7687 .type = PERF_RECORD_AUX, 7688 .misc = 0, 7689 .size = sizeof(rec), 7690 }, 7691 .offset = head, 7692 .size = size, 7693 .flags = flags, 7694 }; 7695 int ret; 7696 7697 perf_event_header__init_id(&rec.header, &sample, event); 7698 ret = perf_output_begin(&handle, event, rec.header.size); 7699 7700 if (ret) 7701 return; 7702 7703 perf_output_put(&handle, rec); 7704 perf_event__output_id_sample(event, &handle, &sample); 7705 7706 perf_output_end(&handle); 7707 } 7708 7709 /* 7710 * Lost/dropped samples logging 7711 */ 7712 void perf_log_lost_samples(struct perf_event *event, u64 lost) 7713 { 7714 struct perf_output_handle handle; 7715 struct perf_sample_data sample; 7716 int ret; 7717 7718 struct { 7719 struct perf_event_header header; 7720 u64 lost; 7721 } lost_samples_event = { 7722 .header = { 7723 .type = PERF_RECORD_LOST_SAMPLES, 7724 .misc = 0, 7725 .size = sizeof(lost_samples_event), 7726 }, 7727 .lost = lost, 7728 }; 7729 7730 perf_event_header__init_id(&lost_samples_event.header, &sample, event); 7731 7732 ret = perf_output_begin(&handle, event, 7733 lost_samples_event.header.size); 7734 if (ret) 7735 return; 7736 7737 perf_output_put(&handle, lost_samples_event); 7738 perf_event__output_id_sample(event, &handle, &sample); 7739 perf_output_end(&handle); 7740 } 7741 7742 /* 7743 * context_switch tracking 7744 */ 7745 7746 struct perf_switch_event { 7747 struct task_struct *task; 7748 struct task_struct *next_prev; 7749 7750 struct { 7751 struct perf_event_header header; 7752 u32 next_prev_pid; 7753 u32 next_prev_tid; 7754 } event_id; 7755 }; 7756 7757 static int perf_event_switch_match(struct perf_event *event) 7758 { 7759 return event->attr.context_switch; 7760 } 7761 7762 static void perf_event_switch_output(struct perf_event *event, void *data) 7763 { 7764 struct perf_switch_event *se = data; 7765 struct perf_output_handle handle; 7766 struct perf_sample_data sample; 7767 int ret; 7768 7769 if (!perf_event_switch_match(event)) 7770 return; 7771 7772 /* Only CPU-wide events are allowed to see next/prev pid/tid */ 7773 if (event->ctx->task) { 7774 se->event_id.header.type = PERF_RECORD_SWITCH; 7775 se->event_id.header.size = sizeof(se->event_id.header); 7776 } else { 7777 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE; 7778 se->event_id.header.size = sizeof(se->event_id); 7779 se->event_id.next_prev_pid = 7780 perf_event_pid(event, se->next_prev); 7781 se->event_id.next_prev_tid = 7782 perf_event_tid(event, se->next_prev); 7783 } 7784 7785 perf_event_header__init_id(&se->event_id.header, &sample, event); 7786 7787 ret = perf_output_begin(&handle, event, se->event_id.header.size); 7788 if (ret) 7789 return; 7790 7791 if (event->ctx->task) 7792 perf_output_put(&handle, se->event_id.header); 7793 else 7794 perf_output_put(&handle, se->event_id); 7795 7796 perf_event__output_id_sample(event, &handle, &sample); 7797 7798 perf_output_end(&handle); 7799 } 7800 7801 static void perf_event_switch(struct task_struct *task, 7802 struct task_struct *next_prev, bool sched_in) 7803 { 7804 struct perf_switch_event switch_event; 7805 7806 /* N.B. caller checks nr_switch_events != 0 */ 7807 7808 switch_event = (struct perf_switch_event){ 7809 .task = task, 7810 .next_prev = next_prev, 7811 .event_id = { 7812 .header = { 7813 /* .type */ 7814 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT, 7815 /* .size */ 7816 }, 7817 /* .next_prev_pid */ 7818 /* .next_prev_tid */ 7819 }, 7820 }; 7821 7822 if (!sched_in && task->state == TASK_RUNNING) 7823 switch_event.event_id.header.misc |= 7824 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT; 7825 7826 perf_iterate_sb(perf_event_switch_output, 7827 &switch_event, 7828 NULL); 7829 } 7830 7831 /* 7832 * IRQ throttle logging 7833 */ 7834 7835 static void perf_log_throttle(struct perf_event *event, int enable) 7836 { 7837 struct perf_output_handle handle; 7838 struct perf_sample_data sample; 7839 int ret; 7840 7841 struct { 7842 struct perf_event_header header; 7843 u64 time; 7844 u64 id; 7845 u64 stream_id; 7846 } throttle_event = { 7847 .header = { 7848 .type = PERF_RECORD_THROTTLE, 7849 .misc = 0, 7850 .size = sizeof(throttle_event), 7851 }, 7852 .time = perf_event_clock(event), 7853 .id = primary_event_id(event), 7854 .stream_id = event->id, 7855 }; 7856 7857 if (enable) 7858 throttle_event.header.type = PERF_RECORD_UNTHROTTLE; 7859 7860 perf_event_header__init_id(&throttle_event.header, &sample, event); 7861 7862 ret = perf_output_begin(&handle, event, 7863 throttle_event.header.size); 7864 if (ret) 7865 return; 7866 7867 perf_output_put(&handle, throttle_event); 7868 perf_event__output_id_sample(event, &handle, &sample); 7869 perf_output_end(&handle); 7870 } 7871 7872 /* 7873 * ksymbol register/unregister tracking 7874 */ 7875 7876 struct perf_ksymbol_event { 7877 const char *name; 7878 int name_len; 7879 struct { 7880 struct perf_event_header header; 7881 u64 addr; 7882 u32 len; 7883 u16 ksym_type; 7884 u16 flags; 7885 } event_id; 7886 }; 7887 7888 static int perf_event_ksymbol_match(struct perf_event *event) 7889 { 7890 return event->attr.ksymbol; 7891 } 7892 7893 static void perf_event_ksymbol_output(struct perf_event *event, void *data) 7894 { 7895 struct perf_ksymbol_event *ksymbol_event = data; 7896 struct perf_output_handle handle; 7897 struct perf_sample_data sample; 7898 int ret; 7899 7900 if (!perf_event_ksymbol_match(event)) 7901 return; 7902 7903 perf_event_header__init_id(&ksymbol_event->event_id.header, 7904 &sample, event); 7905 ret = perf_output_begin(&handle, event, 7906 ksymbol_event->event_id.header.size); 7907 if (ret) 7908 return; 7909 7910 perf_output_put(&handle, ksymbol_event->event_id); 7911 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len); 7912 perf_event__output_id_sample(event, &handle, &sample); 7913 7914 perf_output_end(&handle); 7915 } 7916 7917 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister, 7918 const char *sym) 7919 { 7920 struct perf_ksymbol_event ksymbol_event; 7921 char name[KSYM_NAME_LEN]; 7922 u16 flags = 0; 7923 int name_len; 7924 7925 if (!atomic_read(&nr_ksymbol_events)) 7926 return; 7927 7928 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX || 7929 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN) 7930 goto err; 7931 7932 strlcpy(name, sym, KSYM_NAME_LEN); 7933 name_len = strlen(name) + 1; 7934 while (!IS_ALIGNED(name_len, sizeof(u64))) 7935 name[name_len++] = '\0'; 7936 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64)); 7937 7938 if (unregister) 7939 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER; 7940 7941 ksymbol_event = (struct perf_ksymbol_event){ 7942 .name = name, 7943 .name_len = name_len, 7944 .event_id = { 7945 .header = { 7946 .type = PERF_RECORD_KSYMBOL, 7947 .size = sizeof(ksymbol_event.event_id) + 7948 name_len, 7949 }, 7950 .addr = addr, 7951 .len = len, 7952 .ksym_type = ksym_type, 7953 .flags = flags, 7954 }, 7955 }; 7956 7957 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL); 7958 return; 7959 err: 7960 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type); 7961 } 7962 7963 /* 7964 * bpf program load/unload tracking 7965 */ 7966 7967 struct perf_bpf_event { 7968 struct bpf_prog *prog; 7969 struct { 7970 struct perf_event_header header; 7971 u16 type; 7972 u16 flags; 7973 u32 id; 7974 u8 tag[BPF_TAG_SIZE]; 7975 } event_id; 7976 }; 7977 7978 static int perf_event_bpf_match(struct perf_event *event) 7979 { 7980 return event->attr.bpf_event; 7981 } 7982 7983 static void perf_event_bpf_output(struct perf_event *event, void *data) 7984 { 7985 struct perf_bpf_event *bpf_event = data; 7986 struct perf_output_handle handle; 7987 struct perf_sample_data sample; 7988 int ret; 7989 7990 if (!perf_event_bpf_match(event)) 7991 return; 7992 7993 perf_event_header__init_id(&bpf_event->event_id.header, 7994 &sample, event); 7995 ret = perf_output_begin(&handle, event, 7996 bpf_event->event_id.header.size); 7997 if (ret) 7998 return; 7999 8000 perf_output_put(&handle, bpf_event->event_id); 8001 perf_event__output_id_sample(event, &handle, &sample); 8002 8003 perf_output_end(&handle); 8004 } 8005 8006 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog, 8007 enum perf_bpf_event_type type) 8008 { 8009 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD; 8010 char sym[KSYM_NAME_LEN]; 8011 int i; 8012 8013 if (prog->aux->func_cnt == 0) { 8014 bpf_get_prog_name(prog, sym); 8015 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF, 8016 (u64)(unsigned long)prog->bpf_func, 8017 prog->jited_len, unregister, sym); 8018 } else { 8019 for (i = 0; i < prog->aux->func_cnt; i++) { 8020 struct bpf_prog *subprog = prog->aux->func[i]; 8021 8022 bpf_get_prog_name(subprog, sym); 8023 perf_event_ksymbol( 8024 PERF_RECORD_KSYMBOL_TYPE_BPF, 8025 (u64)(unsigned long)subprog->bpf_func, 8026 subprog->jited_len, unregister, sym); 8027 } 8028 } 8029 } 8030 8031 void perf_event_bpf_event(struct bpf_prog *prog, 8032 enum perf_bpf_event_type type, 8033 u16 flags) 8034 { 8035 struct perf_bpf_event bpf_event; 8036 8037 if (type <= PERF_BPF_EVENT_UNKNOWN || 8038 type >= PERF_BPF_EVENT_MAX) 8039 return; 8040 8041 switch (type) { 8042 case PERF_BPF_EVENT_PROG_LOAD: 8043 case PERF_BPF_EVENT_PROG_UNLOAD: 8044 if (atomic_read(&nr_ksymbol_events)) 8045 perf_event_bpf_emit_ksymbols(prog, type); 8046 break; 8047 default: 8048 break; 8049 } 8050 8051 if (!atomic_read(&nr_bpf_events)) 8052 return; 8053 8054 bpf_event = (struct perf_bpf_event){ 8055 .prog = prog, 8056 .event_id = { 8057 .header = { 8058 .type = PERF_RECORD_BPF_EVENT, 8059 .size = sizeof(bpf_event.event_id), 8060 }, 8061 .type = type, 8062 .flags = flags, 8063 .id = prog->aux->id, 8064 }, 8065 }; 8066 8067 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64)); 8068 8069 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE); 8070 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL); 8071 } 8072 8073 void perf_event_itrace_started(struct perf_event *event) 8074 { 8075 event->attach_state |= PERF_ATTACH_ITRACE; 8076 } 8077 8078 static void perf_log_itrace_start(struct perf_event *event) 8079 { 8080 struct perf_output_handle handle; 8081 struct perf_sample_data sample; 8082 struct perf_aux_event { 8083 struct perf_event_header header; 8084 u32 pid; 8085 u32 tid; 8086 } rec; 8087 int ret; 8088 8089 if (event->parent) 8090 event = event->parent; 8091 8092 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) || 8093 event->attach_state & PERF_ATTACH_ITRACE) 8094 return; 8095 8096 rec.header.type = PERF_RECORD_ITRACE_START; 8097 rec.header.misc = 0; 8098 rec.header.size = sizeof(rec); 8099 rec.pid = perf_event_pid(event, current); 8100 rec.tid = perf_event_tid(event, current); 8101 8102 perf_event_header__init_id(&rec.header, &sample, event); 8103 ret = perf_output_begin(&handle, event, rec.header.size); 8104 8105 if (ret) 8106 return; 8107 8108 perf_output_put(&handle, rec); 8109 perf_event__output_id_sample(event, &handle, &sample); 8110 8111 perf_output_end(&handle); 8112 } 8113 8114 static int 8115 __perf_event_account_interrupt(struct perf_event *event, int throttle) 8116 { 8117 struct hw_perf_event *hwc = &event->hw; 8118 int ret = 0; 8119 u64 seq; 8120 8121 seq = __this_cpu_read(perf_throttled_seq); 8122 if (seq != hwc->interrupts_seq) { 8123 hwc->interrupts_seq = seq; 8124 hwc->interrupts = 1; 8125 } else { 8126 hwc->interrupts++; 8127 if (unlikely(throttle 8128 && hwc->interrupts >= max_samples_per_tick)) { 8129 __this_cpu_inc(perf_throttled_count); 8130 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); 8131 hwc->interrupts = MAX_INTERRUPTS; 8132 perf_log_throttle(event, 0); 8133 ret = 1; 8134 } 8135 } 8136 8137 if (event->attr.freq) { 8138 u64 now = perf_clock(); 8139 s64 delta = now - hwc->freq_time_stamp; 8140 8141 hwc->freq_time_stamp = now; 8142 8143 if (delta > 0 && delta < 2*TICK_NSEC) 8144 perf_adjust_period(event, delta, hwc->last_period, true); 8145 } 8146 8147 return ret; 8148 } 8149 8150 int perf_event_account_interrupt(struct perf_event *event) 8151 { 8152 return __perf_event_account_interrupt(event, 1); 8153 } 8154 8155 /* 8156 * Generic event overflow handling, sampling. 8157 */ 8158 8159 static int __perf_event_overflow(struct perf_event *event, 8160 int throttle, struct perf_sample_data *data, 8161 struct pt_regs *regs) 8162 { 8163 int events = atomic_read(&event->event_limit); 8164 int ret = 0; 8165 8166 /* 8167 * Non-sampling counters might still use the PMI to fold short 8168 * hardware counters, ignore those. 8169 */ 8170 if (unlikely(!is_sampling_event(event))) 8171 return 0; 8172 8173 ret = __perf_event_account_interrupt(event, throttle); 8174 8175 /* 8176 * XXX event_limit might not quite work as expected on inherited 8177 * events 8178 */ 8179 8180 event->pending_kill = POLL_IN; 8181 if (events && atomic_dec_and_test(&event->event_limit)) { 8182 ret = 1; 8183 event->pending_kill = POLL_HUP; 8184 8185 perf_event_disable_inatomic(event); 8186 } 8187 8188 READ_ONCE(event->overflow_handler)(event, data, regs); 8189 8190 if (*perf_event_fasync(event) && event->pending_kill) { 8191 event->pending_wakeup = 1; 8192 irq_work_queue(&event->pending); 8193 } 8194 8195 return ret; 8196 } 8197 8198 int perf_event_overflow(struct perf_event *event, 8199 struct perf_sample_data *data, 8200 struct pt_regs *regs) 8201 { 8202 return __perf_event_overflow(event, 1, data, regs); 8203 } 8204 8205 /* 8206 * Generic software event infrastructure 8207 */ 8208 8209 struct swevent_htable { 8210 struct swevent_hlist *swevent_hlist; 8211 struct mutex hlist_mutex; 8212 int hlist_refcount; 8213 8214 /* Recursion avoidance in each contexts */ 8215 int recursion[PERF_NR_CONTEXTS]; 8216 }; 8217 8218 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable); 8219 8220 /* 8221 * We directly increment event->count and keep a second value in 8222 * event->hw.period_left to count intervals. This period event 8223 * is kept in the range [-sample_period, 0] so that we can use the 8224 * sign as trigger. 8225 */ 8226 8227 u64 perf_swevent_set_period(struct perf_event *event) 8228 { 8229 struct hw_perf_event *hwc = &event->hw; 8230 u64 period = hwc->last_period; 8231 u64 nr, offset; 8232 s64 old, val; 8233 8234 hwc->last_period = hwc->sample_period; 8235 8236 again: 8237 old = val = local64_read(&hwc->period_left); 8238 if (val < 0) 8239 return 0; 8240 8241 nr = div64_u64(period + val, period); 8242 offset = nr * period; 8243 val -= offset; 8244 if (local64_cmpxchg(&hwc->period_left, old, val) != old) 8245 goto again; 8246 8247 return nr; 8248 } 8249 8250 static void perf_swevent_overflow(struct perf_event *event, u64 overflow, 8251 struct perf_sample_data *data, 8252 struct pt_regs *regs) 8253 { 8254 struct hw_perf_event *hwc = &event->hw; 8255 int throttle = 0; 8256 8257 if (!overflow) 8258 overflow = perf_swevent_set_period(event); 8259 8260 if (hwc->interrupts == MAX_INTERRUPTS) 8261 return; 8262 8263 for (; overflow; overflow--) { 8264 if (__perf_event_overflow(event, throttle, 8265 data, regs)) { 8266 /* 8267 * We inhibit the overflow from happening when 8268 * hwc->interrupts == MAX_INTERRUPTS. 8269 */ 8270 break; 8271 } 8272 throttle = 1; 8273 } 8274 } 8275 8276 static void perf_swevent_event(struct perf_event *event, u64 nr, 8277 struct perf_sample_data *data, 8278 struct pt_regs *regs) 8279 { 8280 struct hw_perf_event *hwc = &event->hw; 8281 8282 local64_add(nr, &event->count); 8283 8284 if (!regs) 8285 return; 8286 8287 if (!is_sampling_event(event)) 8288 return; 8289 8290 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) { 8291 data->period = nr; 8292 return perf_swevent_overflow(event, 1, data, regs); 8293 } else 8294 data->period = event->hw.last_period; 8295 8296 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq) 8297 return perf_swevent_overflow(event, 1, data, regs); 8298 8299 if (local64_add_negative(nr, &hwc->period_left)) 8300 return; 8301 8302 perf_swevent_overflow(event, 0, data, regs); 8303 } 8304 8305 static int perf_exclude_event(struct perf_event *event, 8306 struct pt_regs *regs) 8307 { 8308 if (event->hw.state & PERF_HES_STOPPED) 8309 return 1; 8310 8311 if (regs) { 8312 if (event->attr.exclude_user && user_mode(regs)) 8313 return 1; 8314 8315 if (event->attr.exclude_kernel && !user_mode(regs)) 8316 return 1; 8317 } 8318 8319 return 0; 8320 } 8321 8322 static int perf_swevent_match(struct perf_event *event, 8323 enum perf_type_id type, 8324 u32 event_id, 8325 struct perf_sample_data *data, 8326 struct pt_regs *regs) 8327 { 8328 if (event->attr.type != type) 8329 return 0; 8330 8331 if (event->attr.config != event_id) 8332 return 0; 8333 8334 if (perf_exclude_event(event, regs)) 8335 return 0; 8336 8337 return 1; 8338 } 8339 8340 static inline u64 swevent_hash(u64 type, u32 event_id) 8341 { 8342 u64 val = event_id | (type << 32); 8343 8344 return hash_64(val, SWEVENT_HLIST_BITS); 8345 } 8346 8347 static inline struct hlist_head * 8348 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id) 8349 { 8350 u64 hash = swevent_hash(type, event_id); 8351 8352 return &hlist->heads[hash]; 8353 } 8354 8355 /* For the read side: events when they trigger */ 8356 static inline struct hlist_head * 8357 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id) 8358 { 8359 struct swevent_hlist *hlist; 8360 8361 hlist = rcu_dereference(swhash->swevent_hlist); 8362 if (!hlist) 8363 return NULL; 8364 8365 return __find_swevent_head(hlist, type, event_id); 8366 } 8367 8368 /* For the event head insertion and removal in the hlist */ 8369 static inline struct hlist_head * 8370 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event) 8371 { 8372 struct swevent_hlist *hlist; 8373 u32 event_id = event->attr.config; 8374 u64 type = event->attr.type; 8375 8376 /* 8377 * Event scheduling is always serialized against hlist allocation 8378 * and release. Which makes the protected version suitable here. 8379 * The context lock guarantees that. 8380 */ 8381 hlist = rcu_dereference_protected(swhash->swevent_hlist, 8382 lockdep_is_held(&event->ctx->lock)); 8383 if (!hlist) 8384 return NULL; 8385 8386 return __find_swevent_head(hlist, type, event_id); 8387 } 8388 8389 static void do_perf_sw_event(enum perf_type_id type, u32 event_id, 8390 u64 nr, 8391 struct perf_sample_data *data, 8392 struct pt_regs *regs) 8393 { 8394 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 8395 struct perf_event *event; 8396 struct hlist_head *head; 8397 8398 rcu_read_lock(); 8399 head = find_swevent_head_rcu(swhash, type, event_id); 8400 if (!head) 8401 goto end; 8402 8403 hlist_for_each_entry_rcu(event, head, hlist_entry) { 8404 if (perf_swevent_match(event, type, event_id, data, regs)) 8405 perf_swevent_event(event, nr, data, regs); 8406 } 8407 end: 8408 rcu_read_unlock(); 8409 } 8410 8411 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]); 8412 8413 int perf_swevent_get_recursion_context(void) 8414 { 8415 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 8416 8417 return get_recursion_context(swhash->recursion); 8418 } 8419 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context); 8420 8421 void perf_swevent_put_recursion_context(int rctx) 8422 { 8423 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 8424 8425 put_recursion_context(swhash->recursion, rctx); 8426 } 8427 8428 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) 8429 { 8430 struct perf_sample_data data; 8431 8432 if (WARN_ON_ONCE(!regs)) 8433 return; 8434 8435 perf_sample_data_init(&data, addr, 0); 8436 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs); 8437 } 8438 8439 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) 8440 { 8441 int rctx; 8442 8443 preempt_disable_notrace(); 8444 rctx = perf_swevent_get_recursion_context(); 8445 if (unlikely(rctx < 0)) 8446 goto fail; 8447 8448 ___perf_sw_event(event_id, nr, regs, addr); 8449 8450 perf_swevent_put_recursion_context(rctx); 8451 fail: 8452 preempt_enable_notrace(); 8453 } 8454 8455 static void perf_swevent_read(struct perf_event *event) 8456 { 8457 } 8458 8459 static int perf_swevent_add(struct perf_event *event, int flags) 8460 { 8461 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 8462 struct hw_perf_event *hwc = &event->hw; 8463 struct hlist_head *head; 8464 8465 if (is_sampling_event(event)) { 8466 hwc->last_period = hwc->sample_period; 8467 perf_swevent_set_period(event); 8468 } 8469 8470 hwc->state = !(flags & PERF_EF_START); 8471 8472 head = find_swevent_head(swhash, event); 8473 if (WARN_ON_ONCE(!head)) 8474 return -EINVAL; 8475 8476 hlist_add_head_rcu(&event->hlist_entry, head); 8477 perf_event_update_userpage(event); 8478 8479 return 0; 8480 } 8481 8482 static void perf_swevent_del(struct perf_event *event, int flags) 8483 { 8484 hlist_del_rcu(&event->hlist_entry); 8485 } 8486 8487 static void perf_swevent_start(struct perf_event *event, int flags) 8488 { 8489 event->hw.state = 0; 8490 } 8491 8492 static void perf_swevent_stop(struct perf_event *event, int flags) 8493 { 8494 event->hw.state = PERF_HES_STOPPED; 8495 } 8496 8497 /* Deref the hlist from the update side */ 8498 static inline struct swevent_hlist * 8499 swevent_hlist_deref(struct swevent_htable *swhash) 8500 { 8501 return rcu_dereference_protected(swhash->swevent_hlist, 8502 lockdep_is_held(&swhash->hlist_mutex)); 8503 } 8504 8505 static void swevent_hlist_release(struct swevent_htable *swhash) 8506 { 8507 struct swevent_hlist *hlist = swevent_hlist_deref(swhash); 8508 8509 if (!hlist) 8510 return; 8511 8512 RCU_INIT_POINTER(swhash->swevent_hlist, NULL); 8513 kfree_rcu(hlist, rcu_head); 8514 } 8515 8516 static void swevent_hlist_put_cpu(int cpu) 8517 { 8518 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 8519 8520 mutex_lock(&swhash->hlist_mutex); 8521 8522 if (!--swhash->hlist_refcount) 8523 swevent_hlist_release(swhash); 8524 8525 mutex_unlock(&swhash->hlist_mutex); 8526 } 8527 8528 static void swevent_hlist_put(void) 8529 { 8530 int cpu; 8531 8532 for_each_possible_cpu(cpu) 8533 swevent_hlist_put_cpu(cpu); 8534 } 8535 8536 static int swevent_hlist_get_cpu(int cpu) 8537 { 8538 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 8539 int err = 0; 8540 8541 mutex_lock(&swhash->hlist_mutex); 8542 if (!swevent_hlist_deref(swhash) && 8543 cpumask_test_cpu(cpu, perf_online_mask)) { 8544 struct swevent_hlist *hlist; 8545 8546 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL); 8547 if (!hlist) { 8548 err = -ENOMEM; 8549 goto exit; 8550 } 8551 rcu_assign_pointer(swhash->swevent_hlist, hlist); 8552 } 8553 swhash->hlist_refcount++; 8554 exit: 8555 mutex_unlock(&swhash->hlist_mutex); 8556 8557 return err; 8558 } 8559 8560 static int swevent_hlist_get(void) 8561 { 8562 int err, cpu, failed_cpu; 8563 8564 mutex_lock(&pmus_lock); 8565 for_each_possible_cpu(cpu) { 8566 err = swevent_hlist_get_cpu(cpu); 8567 if (err) { 8568 failed_cpu = cpu; 8569 goto fail; 8570 } 8571 } 8572 mutex_unlock(&pmus_lock); 8573 return 0; 8574 fail: 8575 for_each_possible_cpu(cpu) { 8576 if (cpu == failed_cpu) 8577 break; 8578 swevent_hlist_put_cpu(cpu); 8579 } 8580 mutex_unlock(&pmus_lock); 8581 return err; 8582 } 8583 8584 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX]; 8585 8586 static void sw_perf_event_destroy(struct perf_event *event) 8587 { 8588 u64 event_id = event->attr.config; 8589 8590 WARN_ON(event->parent); 8591 8592 static_key_slow_dec(&perf_swevent_enabled[event_id]); 8593 swevent_hlist_put(); 8594 } 8595 8596 static int perf_swevent_init(struct perf_event *event) 8597 { 8598 u64 event_id = event->attr.config; 8599 8600 if (event->attr.type != PERF_TYPE_SOFTWARE) 8601 return -ENOENT; 8602 8603 /* 8604 * no branch sampling for software events 8605 */ 8606 if (has_branch_stack(event)) 8607 return -EOPNOTSUPP; 8608 8609 switch (event_id) { 8610 case PERF_COUNT_SW_CPU_CLOCK: 8611 case PERF_COUNT_SW_TASK_CLOCK: 8612 return -ENOENT; 8613 8614 default: 8615 break; 8616 } 8617 8618 if (event_id >= PERF_COUNT_SW_MAX) 8619 return -ENOENT; 8620 8621 if (!event->parent) { 8622 int err; 8623 8624 err = swevent_hlist_get(); 8625 if (err) 8626 return err; 8627 8628 static_key_slow_inc(&perf_swevent_enabled[event_id]); 8629 event->destroy = sw_perf_event_destroy; 8630 } 8631 8632 return 0; 8633 } 8634 8635 static struct pmu perf_swevent = { 8636 .task_ctx_nr = perf_sw_context, 8637 8638 .capabilities = PERF_PMU_CAP_NO_NMI, 8639 8640 .event_init = perf_swevent_init, 8641 .add = perf_swevent_add, 8642 .del = perf_swevent_del, 8643 .start = perf_swevent_start, 8644 .stop = perf_swevent_stop, 8645 .read = perf_swevent_read, 8646 }; 8647 8648 #ifdef CONFIG_EVENT_TRACING 8649 8650 static int perf_tp_filter_match(struct perf_event *event, 8651 struct perf_sample_data *data) 8652 { 8653 void *record = data->raw->frag.data; 8654 8655 /* only top level events have filters set */ 8656 if (event->parent) 8657 event = event->parent; 8658 8659 if (likely(!event->filter) || filter_match_preds(event->filter, record)) 8660 return 1; 8661 return 0; 8662 } 8663 8664 static int perf_tp_event_match(struct perf_event *event, 8665 struct perf_sample_data *data, 8666 struct pt_regs *regs) 8667 { 8668 if (event->hw.state & PERF_HES_STOPPED) 8669 return 0; 8670 /* 8671 * If exclude_kernel, only trace user-space tracepoints (uprobes) 8672 */ 8673 if (event->attr.exclude_kernel && !user_mode(regs)) 8674 return 0; 8675 8676 if (!perf_tp_filter_match(event, data)) 8677 return 0; 8678 8679 return 1; 8680 } 8681 8682 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx, 8683 struct trace_event_call *call, u64 count, 8684 struct pt_regs *regs, struct hlist_head *head, 8685 struct task_struct *task) 8686 { 8687 if (bpf_prog_array_valid(call)) { 8688 *(struct pt_regs **)raw_data = regs; 8689 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) { 8690 perf_swevent_put_recursion_context(rctx); 8691 return; 8692 } 8693 } 8694 perf_tp_event(call->event.type, count, raw_data, size, regs, head, 8695 rctx, task); 8696 } 8697 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit); 8698 8699 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size, 8700 struct pt_regs *regs, struct hlist_head *head, int rctx, 8701 struct task_struct *task) 8702 { 8703 struct perf_sample_data data; 8704 struct perf_event *event; 8705 8706 struct perf_raw_record raw = { 8707 .frag = { 8708 .size = entry_size, 8709 .data = record, 8710 }, 8711 }; 8712 8713 perf_sample_data_init(&data, 0, 0); 8714 data.raw = &raw; 8715 8716 perf_trace_buf_update(record, event_type); 8717 8718 hlist_for_each_entry_rcu(event, head, hlist_entry) { 8719 if (perf_tp_event_match(event, &data, regs)) 8720 perf_swevent_event(event, count, &data, regs); 8721 } 8722 8723 /* 8724 * If we got specified a target task, also iterate its context and 8725 * deliver this event there too. 8726 */ 8727 if (task && task != current) { 8728 struct perf_event_context *ctx; 8729 struct trace_entry *entry = record; 8730 8731 rcu_read_lock(); 8732 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]); 8733 if (!ctx) 8734 goto unlock; 8735 8736 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 8737 if (event->cpu != smp_processor_id()) 8738 continue; 8739 if (event->attr.type != PERF_TYPE_TRACEPOINT) 8740 continue; 8741 if (event->attr.config != entry->type) 8742 continue; 8743 if (perf_tp_event_match(event, &data, regs)) 8744 perf_swevent_event(event, count, &data, regs); 8745 } 8746 unlock: 8747 rcu_read_unlock(); 8748 } 8749 8750 perf_swevent_put_recursion_context(rctx); 8751 } 8752 EXPORT_SYMBOL_GPL(perf_tp_event); 8753 8754 static void tp_perf_event_destroy(struct perf_event *event) 8755 { 8756 perf_trace_destroy(event); 8757 } 8758 8759 static int perf_tp_event_init(struct perf_event *event) 8760 { 8761 int err; 8762 8763 if (event->attr.type != PERF_TYPE_TRACEPOINT) 8764 return -ENOENT; 8765 8766 /* 8767 * no branch sampling for tracepoint events 8768 */ 8769 if (has_branch_stack(event)) 8770 return -EOPNOTSUPP; 8771 8772 err = perf_trace_init(event); 8773 if (err) 8774 return err; 8775 8776 event->destroy = tp_perf_event_destroy; 8777 8778 return 0; 8779 } 8780 8781 static struct pmu perf_tracepoint = { 8782 .task_ctx_nr = perf_sw_context, 8783 8784 .event_init = perf_tp_event_init, 8785 .add = perf_trace_add, 8786 .del = perf_trace_del, 8787 .start = perf_swevent_start, 8788 .stop = perf_swevent_stop, 8789 .read = perf_swevent_read, 8790 }; 8791 8792 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS) 8793 /* 8794 * Flags in config, used by dynamic PMU kprobe and uprobe 8795 * The flags should match following PMU_FORMAT_ATTR(). 8796 * 8797 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe 8798 * if not set, create kprobe/uprobe 8799 * 8800 * The following values specify a reference counter (or semaphore in the 8801 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically 8802 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset. 8803 * 8804 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset 8805 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left 8806 */ 8807 enum perf_probe_config { 8808 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */ 8809 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32, 8810 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS, 8811 }; 8812 8813 PMU_FORMAT_ATTR(retprobe, "config:0"); 8814 #endif 8815 8816 #ifdef CONFIG_KPROBE_EVENTS 8817 static struct attribute *kprobe_attrs[] = { 8818 &format_attr_retprobe.attr, 8819 NULL, 8820 }; 8821 8822 static struct attribute_group kprobe_format_group = { 8823 .name = "format", 8824 .attrs = kprobe_attrs, 8825 }; 8826 8827 static const struct attribute_group *kprobe_attr_groups[] = { 8828 &kprobe_format_group, 8829 NULL, 8830 }; 8831 8832 static int perf_kprobe_event_init(struct perf_event *event); 8833 static struct pmu perf_kprobe = { 8834 .task_ctx_nr = perf_sw_context, 8835 .event_init = perf_kprobe_event_init, 8836 .add = perf_trace_add, 8837 .del = perf_trace_del, 8838 .start = perf_swevent_start, 8839 .stop = perf_swevent_stop, 8840 .read = perf_swevent_read, 8841 .attr_groups = kprobe_attr_groups, 8842 }; 8843 8844 static int perf_kprobe_event_init(struct perf_event *event) 8845 { 8846 int err; 8847 bool is_retprobe; 8848 8849 if (event->attr.type != perf_kprobe.type) 8850 return -ENOENT; 8851 8852 if (!capable(CAP_SYS_ADMIN)) 8853 return -EACCES; 8854 8855 /* 8856 * no branch sampling for probe events 8857 */ 8858 if (has_branch_stack(event)) 8859 return -EOPNOTSUPP; 8860 8861 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE; 8862 err = perf_kprobe_init(event, is_retprobe); 8863 if (err) 8864 return err; 8865 8866 event->destroy = perf_kprobe_destroy; 8867 8868 return 0; 8869 } 8870 #endif /* CONFIG_KPROBE_EVENTS */ 8871 8872 #ifdef CONFIG_UPROBE_EVENTS 8873 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63"); 8874 8875 static struct attribute *uprobe_attrs[] = { 8876 &format_attr_retprobe.attr, 8877 &format_attr_ref_ctr_offset.attr, 8878 NULL, 8879 }; 8880 8881 static struct attribute_group uprobe_format_group = { 8882 .name = "format", 8883 .attrs = uprobe_attrs, 8884 }; 8885 8886 static const struct attribute_group *uprobe_attr_groups[] = { 8887 &uprobe_format_group, 8888 NULL, 8889 }; 8890 8891 static int perf_uprobe_event_init(struct perf_event *event); 8892 static struct pmu perf_uprobe = { 8893 .task_ctx_nr = perf_sw_context, 8894 .event_init = perf_uprobe_event_init, 8895 .add = perf_trace_add, 8896 .del = perf_trace_del, 8897 .start = perf_swevent_start, 8898 .stop = perf_swevent_stop, 8899 .read = perf_swevent_read, 8900 .attr_groups = uprobe_attr_groups, 8901 }; 8902 8903 static int perf_uprobe_event_init(struct perf_event *event) 8904 { 8905 int err; 8906 unsigned long ref_ctr_offset; 8907 bool is_retprobe; 8908 8909 if (event->attr.type != perf_uprobe.type) 8910 return -ENOENT; 8911 8912 if (!capable(CAP_SYS_ADMIN)) 8913 return -EACCES; 8914 8915 /* 8916 * no branch sampling for probe events 8917 */ 8918 if (has_branch_stack(event)) 8919 return -EOPNOTSUPP; 8920 8921 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE; 8922 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT; 8923 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe); 8924 if (err) 8925 return err; 8926 8927 event->destroy = perf_uprobe_destroy; 8928 8929 return 0; 8930 } 8931 #endif /* CONFIG_UPROBE_EVENTS */ 8932 8933 static inline void perf_tp_register(void) 8934 { 8935 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT); 8936 #ifdef CONFIG_KPROBE_EVENTS 8937 perf_pmu_register(&perf_kprobe, "kprobe", -1); 8938 #endif 8939 #ifdef CONFIG_UPROBE_EVENTS 8940 perf_pmu_register(&perf_uprobe, "uprobe", -1); 8941 #endif 8942 } 8943 8944 static void perf_event_free_filter(struct perf_event *event) 8945 { 8946 ftrace_profile_free_filter(event); 8947 } 8948 8949 #ifdef CONFIG_BPF_SYSCALL 8950 static void bpf_overflow_handler(struct perf_event *event, 8951 struct perf_sample_data *data, 8952 struct pt_regs *regs) 8953 { 8954 struct bpf_perf_event_data_kern ctx = { 8955 .data = data, 8956 .event = event, 8957 }; 8958 int ret = 0; 8959 8960 ctx.regs = perf_arch_bpf_user_pt_regs(regs); 8961 preempt_disable(); 8962 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) 8963 goto out; 8964 rcu_read_lock(); 8965 ret = BPF_PROG_RUN(event->prog, &ctx); 8966 rcu_read_unlock(); 8967 out: 8968 __this_cpu_dec(bpf_prog_active); 8969 preempt_enable(); 8970 if (!ret) 8971 return; 8972 8973 event->orig_overflow_handler(event, data, regs); 8974 } 8975 8976 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd) 8977 { 8978 struct bpf_prog *prog; 8979 8980 if (event->overflow_handler_context) 8981 /* hw breakpoint or kernel counter */ 8982 return -EINVAL; 8983 8984 if (event->prog) 8985 return -EEXIST; 8986 8987 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT); 8988 if (IS_ERR(prog)) 8989 return PTR_ERR(prog); 8990 8991 event->prog = prog; 8992 event->orig_overflow_handler = READ_ONCE(event->overflow_handler); 8993 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler); 8994 return 0; 8995 } 8996 8997 static void perf_event_free_bpf_handler(struct perf_event *event) 8998 { 8999 struct bpf_prog *prog = event->prog; 9000 9001 if (!prog) 9002 return; 9003 9004 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler); 9005 event->prog = NULL; 9006 bpf_prog_put(prog); 9007 } 9008 #else 9009 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd) 9010 { 9011 return -EOPNOTSUPP; 9012 } 9013 static void perf_event_free_bpf_handler(struct perf_event *event) 9014 { 9015 } 9016 #endif 9017 9018 /* 9019 * returns true if the event is a tracepoint, or a kprobe/upprobe created 9020 * with perf_event_open() 9021 */ 9022 static inline bool perf_event_is_tracing(struct perf_event *event) 9023 { 9024 if (event->pmu == &perf_tracepoint) 9025 return true; 9026 #ifdef CONFIG_KPROBE_EVENTS 9027 if (event->pmu == &perf_kprobe) 9028 return true; 9029 #endif 9030 #ifdef CONFIG_UPROBE_EVENTS 9031 if (event->pmu == &perf_uprobe) 9032 return true; 9033 #endif 9034 return false; 9035 } 9036 9037 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) 9038 { 9039 bool is_kprobe, is_tracepoint, is_syscall_tp; 9040 struct bpf_prog *prog; 9041 int ret; 9042 9043 if (!perf_event_is_tracing(event)) 9044 return perf_event_set_bpf_handler(event, prog_fd); 9045 9046 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE; 9047 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT; 9048 is_syscall_tp = is_syscall_trace_event(event->tp_event); 9049 if (!is_kprobe && !is_tracepoint && !is_syscall_tp) 9050 /* bpf programs can only be attached to u/kprobe or tracepoint */ 9051 return -EINVAL; 9052 9053 prog = bpf_prog_get(prog_fd); 9054 if (IS_ERR(prog)) 9055 return PTR_ERR(prog); 9056 9057 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) || 9058 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) || 9059 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) { 9060 /* valid fd, but invalid bpf program type */ 9061 bpf_prog_put(prog); 9062 return -EINVAL; 9063 } 9064 9065 /* Kprobe override only works for kprobes, not uprobes. */ 9066 if (prog->kprobe_override && 9067 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) { 9068 bpf_prog_put(prog); 9069 return -EINVAL; 9070 } 9071 9072 if (is_tracepoint || is_syscall_tp) { 9073 int off = trace_event_get_offsets(event->tp_event); 9074 9075 if (prog->aux->max_ctx_offset > off) { 9076 bpf_prog_put(prog); 9077 return -EACCES; 9078 } 9079 } 9080 9081 ret = perf_event_attach_bpf_prog(event, prog); 9082 if (ret) 9083 bpf_prog_put(prog); 9084 return ret; 9085 } 9086 9087 static void perf_event_free_bpf_prog(struct perf_event *event) 9088 { 9089 if (!perf_event_is_tracing(event)) { 9090 perf_event_free_bpf_handler(event); 9091 return; 9092 } 9093 perf_event_detach_bpf_prog(event); 9094 } 9095 9096 #else 9097 9098 static inline void perf_tp_register(void) 9099 { 9100 } 9101 9102 static void perf_event_free_filter(struct perf_event *event) 9103 { 9104 } 9105 9106 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) 9107 { 9108 return -ENOENT; 9109 } 9110 9111 static void perf_event_free_bpf_prog(struct perf_event *event) 9112 { 9113 } 9114 #endif /* CONFIG_EVENT_TRACING */ 9115 9116 #ifdef CONFIG_HAVE_HW_BREAKPOINT 9117 void perf_bp_event(struct perf_event *bp, void *data) 9118 { 9119 struct perf_sample_data sample; 9120 struct pt_regs *regs = data; 9121 9122 perf_sample_data_init(&sample, bp->attr.bp_addr, 0); 9123 9124 if (!bp->hw.state && !perf_exclude_event(bp, regs)) 9125 perf_swevent_event(bp, 1, &sample, regs); 9126 } 9127 #endif 9128 9129 /* 9130 * Allocate a new address filter 9131 */ 9132 static struct perf_addr_filter * 9133 perf_addr_filter_new(struct perf_event *event, struct list_head *filters) 9134 { 9135 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu); 9136 struct perf_addr_filter *filter; 9137 9138 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node); 9139 if (!filter) 9140 return NULL; 9141 9142 INIT_LIST_HEAD(&filter->entry); 9143 list_add_tail(&filter->entry, filters); 9144 9145 return filter; 9146 } 9147 9148 static void free_filters_list(struct list_head *filters) 9149 { 9150 struct perf_addr_filter *filter, *iter; 9151 9152 list_for_each_entry_safe(filter, iter, filters, entry) { 9153 path_put(&filter->path); 9154 list_del(&filter->entry); 9155 kfree(filter); 9156 } 9157 } 9158 9159 /* 9160 * Free existing address filters and optionally install new ones 9161 */ 9162 static void perf_addr_filters_splice(struct perf_event *event, 9163 struct list_head *head) 9164 { 9165 unsigned long flags; 9166 LIST_HEAD(list); 9167 9168 if (!has_addr_filter(event)) 9169 return; 9170 9171 /* don't bother with children, they don't have their own filters */ 9172 if (event->parent) 9173 return; 9174 9175 raw_spin_lock_irqsave(&event->addr_filters.lock, flags); 9176 9177 list_splice_init(&event->addr_filters.list, &list); 9178 if (head) 9179 list_splice(head, &event->addr_filters.list); 9180 9181 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags); 9182 9183 free_filters_list(&list); 9184 } 9185 9186 /* 9187 * Scan through mm's vmas and see if one of them matches the 9188 * @filter; if so, adjust filter's address range. 9189 * Called with mm::mmap_sem down for reading. 9190 */ 9191 static void perf_addr_filter_apply(struct perf_addr_filter *filter, 9192 struct mm_struct *mm, 9193 struct perf_addr_filter_range *fr) 9194 { 9195 struct vm_area_struct *vma; 9196 9197 for (vma = mm->mmap; vma; vma = vma->vm_next) { 9198 if (!vma->vm_file) 9199 continue; 9200 9201 if (perf_addr_filter_vma_adjust(filter, vma, fr)) 9202 return; 9203 } 9204 } 9205 9206 /* 9207 * Update event's address range filters based on the 9208 * task's existing mappings, if any. 9209 */ 9210 static void perf_event_addr_filters_apply(struct perf_event *event) 9211 { 9212 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 9213 struct task_struct *task = READ_ONCE(event->ctx->task); 9214 struct perf_addr_filter *filter; 9215 struct mm_struct *mm = NULL; 9216 unsigned int count = 0; 9217 unsigned long flags; 9218 9219 /* 9220 * We may observe TASK_TOMBSTONE, which means that the event tear-down 9221 * will stop on the parent's child_mutex that our caller is also holding 9222 */ 9223 if (task == TASK_TOMBSTONE) 9224 return; 9225 9226 if (ifh->nr_file_filters) { 9227 mm = get_task_mm(event->ctx->task); 9228 if (!mm) 9229 goto restart; 9230 9231 down_read(&mm->mmap_sem); 9232 } 9233 9234 raw_spin_lock_irqsave(&ifh->lock, flags); 9235 list_for_each_entry(filter, &ifh->list, entry) { 9236 if (filter->path.dentry) { 9237 /* 9238 * Adjust base offset if the filter is associated to a 9239 * binary that needs to be mapped: 9240 */ 9241 event->addr_filter_ranges[count].start = 0; 9242 event->addr_filter_ranges[count].size = 0; 9243 9244 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]); 9245 } else { 9246 event->addr_filter_ranges[count].start = filter->offset; 9247 event->addr_filter_ranges[count].size = filter->size; 9248 } 9249 9250 count++; 9251 } 9252 9253 event->addr_filters_gen++; 9254 raw_spin_unlock_irqrestore(&ifh->lock, flags); 9255 9256 if (ifh->nr_file_filters) { 9257 up_read(&mm->mmap_sem); 9258 9259 mmput(mm); 9260 } 9261 9262 restart: 9263 perf_event_stop(event, 1); 9264 } 9265 9266 /* 9267 * Address range filtering: limiting the data to certain 9268 * instruction address ranges. Filters are ioctl()ed to us from 9269 * userspace as ascii strings. 9270 * 9271 * Filter string format: 9272 * 9273 * ACTION RANGE_SPEC 9274 * where ACTION is one of the 9275 * * "filter": limit the trace to this region 9276 * * "start": start tracing from this address 9277 * * "stop": stop tracing at this address/region; 9278 * RANGE_SPEC is 9279 * * for kernel addresses: <start address>[/<size>] 9280 * * for object files: <start address>[/<size>]@</path/to/object/file> 9281 * 9282 * if <size> is not specified or is zero, the range is treated as a single 9283 * address; not valid for ACTION=="filter". 9284 */ 9285 enum { 9286 IF_ACT_NONE = -1, 9287 IF_ACT_FILTER, 9288 IF_ACT_START, 9289 IF_ACT_STOP, 9290 IF_SRC_FILE, 9291 IF_SRC_KERNEL, 9292 IF_SRC_FILEADDR, 9293 IF_SRC_KERNELADDR, 9294 }; 9295 9296 enum { 9297 IF_STATE_ACTION = 0, 9298 IF_STATE_SOURCE, 9299 IF_STATE_END, 9300 }; 9301 9302 static const match_table_t if_tokens = { 9303 { IF_ACT_FILTER, "filter" }, 9304 { IF_ACT_START, "start" }, 9305 { IF_ACT_STOP, "stop" }, 9306 { IF_SRC_FILE, "%u/%u@%s" }, 9307 { IF_SRC_KERNEL, "%u/%u" }, 9308 { IF_SRC_FILEADDR, "%u@%s" }, 9309 { IF_SRC_KERNELADDR, "%u" }, 9310 { IF_ACT_NONE, NULL }, 9311 }; 9312 9313 /* 9314 * Address filter string parser 9315 */ 9316 static int 9317 perf_event_parse_addr_filter(struct perf_event *event, char *fstr, 9318 struct list_head *filters) 9319 { 9320 struct perf_addr_filter *filter = NULL; 9321 char *start, *orig, *filename = NULL; 9322 substring_t args[MAX_OPT_ARGS]; 9323 int state = IF_STATE_ACTION, token; 9324 unsigned int kernel = 0; 9325 int ret = -EINVAL; 9326 9327 orig = fstr = kstrdup(fstr, GFP_KERNEL); 9328 if (!fstr) 9329 return -ENOMEM; 9330 9331 while ((start = strsep(&fstr, " ,\n")) != NULL) { 9332 static const enum perf_addr_filter_action_t actions[] = { 9333 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER, 9334 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START, 9335 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP, 9336 }; 9337 ret = -EINVAL; 9338 9339 if (!*start) 9340 continue; 9341 9342 /* filter definition begins */ 9343 if (state == IF_STATE_ACTION) { 9344 filter = perf_addr_filter_new(event, filters); 9345 if (!filter) 9346 goto fail; 9347 } 9348 9349 token = match_token(start, if_tokens, args); 9350 switch (token) { 9351 case IF_ACT_FILTER: 9352 case IF_ACT_START: 9353 case IF_ACT_STOP: 9354 if (state != IF_STATE_ACTION) 9355 goto fail; 9356 9357 filter->action = actions[token]; 9358 state = IF_STATE_SOURCE; 9359 break; 9360 9361 case IF_SRC_KERNELADDR: 9362 case IF_SRC_KERNEL: 9363 kernel = 1; 9364 /* fall through */ 9365 9366 case IF_SRC_FILEADDR: 9367 case IF_SRC_FILE: 9368 if (state != IF_STATE_SOURCE) 9369 goto fail; 9370 9371 *args[0].to = 0; 9372 ret = kstrtoul(args[0].from, 0, &filter->offset); 9373 if (ret) 9374 goto fail; 9375 9376 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) { 9377 *args[1].to = 0; 9378 ret = kstrtoul(args[1].from, 0, &filter->size); 9379 if (ret) 9380 goto fail; 9381 } 9382 9383 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) { 9384 int fpos = token == IF_SRC_FILE ? 2 : 1; 9385 9386 filename = match_strdup(&args[fpos]); 9387 if (!filename) { 9388 ret = -ENOMEM; 9389 goto fail; 9390 } 9391 } 9392 9393 state = IF_STATE_END; 9394 break; 9395 9396 default: 9397 goto fail; 9398 } 9399 9400 /* 9401 * Filter definition is fully parsed, validate and install it. 9402 * Make sure that it doesn't contradict itself or the event's 9403 * attribute. 9404 */ 9405 if (state == IF_STATE_END) { 9406 ret = -EINVAL; 9407 if (kernel && event->attr.exclude_kernel) 9408 goto fail; 9409 9410 /* 9411 * ACTION "filter" must have a non-zero length region 9412 * specified. 9413 */ 9414 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER && 9415 !filter->size) 9416 goto fail; 9417 9418 if (!kernel) { 9419 if (!filename) 9420 goto fail; 9421 9422 /* 9423 * For now, we only support file-based filters 9424 * in per-task events; doing so for CPU-wide 9425 * events requires additional context switching 9426 * trickery, since same object code will be 9427 * mapped at different virtual addresses in 9428 * different processes. 9429 */ 9430 ret = -EOPNOTSUPP; 9431 if (!event->ctx->task) 9432 goto fail_free_name; 9433 9434 /* look up the path and grab its inode */ 9435 ret = kern_path(filename, LOOKUP_FOLLOW, 9436 &filter->path); 9437 if (ret) 9438 goto fail_free_name; 9439 9440 kfree(filename); 9441 filename = NULL; 9442 9443 ret = -EINVAL; 9444 if (!filter->path.dentry || 9445 !S_ISREG(d_inode(filter->path.dentry) 9446 ->i_mode)) 9447 goto fail; 9448 9449 event->addr_filters.nr_file_filters++; 9450 } 9451 9452 /* ready to consume more filters */ 9453 state = IF_STATE_ACTION; 9454 filter = NULL; 9455 } 9456 } 9457 9458 if (state != IF_STATE_ACTION) 9459 goto fail; 9460 9461 kfree(orig); 9462 9463 return 0; 9464 9465 fail_free_name: 9466 kfree(filename); 9467 fail: 9468 free_filters_list(filters); 9469 kfree(orig); 9470 9471 return ret; 9472 } 9473 9474 static int 9475 perf_event_set_addr_filter(struct perf_event *event, char *filter_str) 9476 { 9477 LIST_HEAD(filters); 9478 int ret; 9479 9480 /* 9481 * Since this is called in perf_ioctl() path, we're already holding 9482 * ctx::mutex. 9483 */ 9484 lockdep_assert_held(&event->ctx->mutex); 9485 9486 if (WARN_ON_ONCE(event->parent)) 9487 return -EINVAL; 9488 9489 ret = perf_event_parse_addr_filter(event, filter_str, &filters); 9490 if (ret) 9491 goto fail_clear_files; 9492 9493 ret = event->pmu->addr_filters_validate(&filters); 9494 if (ret) 9495 goto fail_free_filters; 9496 9497 /* remove existing filters, if any */ 9498 perf_addr_filters_splice(event, &filters); 9499 9500 /* install new filters */ 9501 perf_event_for_each_child(event, perf_event_addr_filters_apply); 9502 9503 return ret; 9504 9505 fail_free_filters: 9506 free_filters_list(&filters); 9507 9508 fail_clear_files: 9509 event->addr_filters.nr_file_filters = 0; 9510 9511 return ret; 9512 } 9513 9514 static int perf_event_set_filter(struct perf_event *event, void __user *arg) 9515 { 9516 int ret = -EINVAL; 9517 char *filter_str; 9518 9519 filter_str = strndup_user(arg, PAGE_SIZE); 9520 if (IS_ERR(filter_str)) 9521 return PTR_ERR(filter_str); 9522 9523 #ifdef CONFIG_EVENT_TRACING 9524 if (perf_event_is_tracing(event)) { 9525 struct perf_event_context *ctx = event->ctx; 9526 9527 /* 9528 * Beware, here be dragons!! 9529 * 9530 * the tracepoint muck will deadlock against ctx->mutex, but 9531 * the tracepoint stuff does not actually need it. So 9532 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we 9533 * already have a reference on ctx. 9534 * 9535 * This can result in event getting moved to a different ctx, 9536 * but that does not affect the tracepoint state. 9537 */ 9538 mutex_unlock(&ctx->mutex); 9539 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str); 9540 mutex_lock(&ctx->mutex); 9541 } else 9542 #endif 9543 if (has_addr_filter(event)) 9544 ret = perf_event_set_addr_filter(event, filter_str); 9545 9546 kfree(filter_str); 9547 return ret; 9548 } 9549 9550 /* 9551 * hrtimer based swevent callback 9552 */ 9553 9554 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer) 9555 { 9556 enum hrtimer_restart ret = HRTIMER_RESTART; 9557 struct perf_sample_data data; 9558 struct pt_regs *regs; 9559 struct perf_event *event; 9560 u64 period; 9561 9562 event = container_of(hrtimer, struct perf_event, hw.hrtimer); 9563 9564 if (event->state != PERF_EVENT_STATE_ACTIVE) 9565 return HRTIMER_NORESTART; 9566 9567 event->pmu->read(event); 9568 9569 perf_sample_data_init(&data, 0, event->hw.last_period); 9570 regs = get_irq_regs(); 9571 9572 if (regs && !perf_exclude_event(event, regs)) { 9573 if (!(event->attr.exclude_idle && is_idle_task(current))) 9574 if (__perf_event_overflow(event, 1, &data, regs)) 9575 ret = HRTIMER_NORESTART; 9576 } 9577 9578 period = max_t(u64, 10000, event->hw.sample_period); 9579 hrtimer_forward_now(hrtimer, ns_to_ktime(period)); 9580 9581 return ret; 9582 } 9583 9584 static void perf_swevent_start_hrtimer(struct perf_event *event) 9585 { 9586 struct hw_perf_event *hwc = &event->hw; 9587 s64 period; 9588 9589 if (!is_sampling_event(event)) 9590 return; 9591 9592 period = local64_read(&hwc->period_left); 9593 if (period) { 9594 if (period < 0) 9595 period = 10000; 9596 9597 local64_set(&hwc->period_left, 0); 9598 } else { 9599 period = max_t(u64, 10000, hwc->sample_period); 9600 } 9601 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period), 9602 HRTIMER_MODE_REL_PINNED_HARD); 9603 } 9604 9605 static void perf_swevent_cancel_hrtimer(struct perf_event *event) 9606 { 9607 struct hw_perf_event *hwc = &event->hw; 9608 9609 if (is_sampling_event(event)) { 9610 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer); 9611 local64_set(&hwc->period_left, ktime_to_ns(remaining)); 9612 9613 hrtimer_cancel(&hwc->hrtimer); 9614 } 9615 } 9616 9617 static void perf_swevent_init_hrtimer(struct perf_event *event) 9618 { 9619 struct hw_perf_event *hwc = &event->hw; 9620 9621 if (!is_sampling_event(event)) 9622 return; 9623 9624 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); 9625 hwc->hrtimer.function = perf_swevent_hrtimer; 9626 9627 /* 9628 * Since hrtimers have a fixed rate, we can do a static freq->period 9629 * mapping and avoid the whole period adjust feedback stuff. 9630 */ 9631 if (event->attr.freq) { 9632 long freq = event->attr.sample_freq; 9633 9634 event->attr.sample_period = NSEC_PER_SEC / freq; 9635 hwc->sample_period = event->attr.sample_period; 9636 local64_set(&hwc->period_left, hwc->sample_period); 9637 hwc->last_period = hwc->sample_period; 9638 event->attr.freq = 0; 9639 } 9640 } 9641 9642 /* 9643 * Software event: cpu wall time clock 9644 */ 9645 9646 static void cpu_clock_event_update(struct perf_event *event) 9647 { 9648 s64 prev; 9649 u64 now; 9650 9651 now = local_clock(); 9652 prev = local64_xchg(&event->hw.prev_count, now); 9653 local64_add(now - prev, &event->count); 9654 } 9655 9656 static void cpu_clock_event_start(struct perf_event *event, int flags) 9657 { 9658 local64_set(&event->hw.prev_count, local_clock()); 9659 perf_swevent_start_hrtimer(event); 9660 } 9661 9662 static void cpu_clock_event_stop(struct perf_event *event, int flags) 9663 { 9664 perf_swevent_cancel_hrtimer(event); 9665 cpu_clock_event_update(event); 9666 } 9667 9668 static int cpu_clock_event_add(struct perf_event *event, int flags) 9669 { 9670 if (flags & PERF_EF_START) 9671 cpu_clock_event_start(event, flags); 9672 perf_event_update_userpage(event); 9673 9674 return 0; 9675 } 9676 9677 static void cpu_clock_event_del(struct perf_event *event, int flags) 9678 { 9679 cpu_clock_event_stop(event, flags); 9680 } 9681 9682 static void cpu_clock_event_read(struct perf_event *event) 9683 { 9684 cpu_clock_event_update(event); 9685 } 9686 9687 static int cpu_clock_event_init(struct perf_event *event) 9688 { 9689 if (event->attr.type != PERF_TYPE_SOFTWARE) 9690 return -ENOENT; 9691 9692 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK) 9693 return -ENOENT; 9694 9695 /* 9696 * no branch sampling for software events 9697 */ 9698 if (has_branch_stack(event)) 9699 return -EOPNOTSUPP; 9700 9701 perf_swevent_init_hrtimer(event); 9702 9703 return 0; 9704 } 9705 9706 static struct pmu perf_cpu_clock = { 9707 .task_ctx_nr = perf_sw_context, 9708 9709 .capabilities = PERF_PMU_CAP_NO_NMI, 9710 9711 .event_init = cpu_clock_event_init, 9712 .add = cpu_clock_event_add, 9713 .del = cpu_clock_event_del, 9714 .start = cpu_clock_event_start, 9715 .stop = cpu_clock_event_stop, 9716 .read = cpu_clock_event_read, 9717 }; 9718 9719 /* 9720 * Software event: task time clock 9721 */ 9722 9723 static void task_clock_event_update(struct perf_event *event, u64 now) 9724 { 9725 u64 prev; 9726 s64 delta; 9727 9728 prev = local64_xchg(&event->hw.prev_count, now); 9729 delta = now - prev; 9730 local64_add(delta, &event->count); 9731 } 9732 9733 static void task_clock_event_start(struct perf_event *event, int flags) 9734 { 9735 local64_set(&event->hw.prev_count, event->ctx->time); 9736 perf_swevent_start_hrtimer(event); 9737 } 9738 9739 static void task_clock_event_stop(struct perf_event *event, int flags) 9740 { 9741 perf_swevent_cancel_hrtimer(event); 9742 task_clock_event_update(event, event->ctx->time); 9743 } 9744 9745 static int task_clock_event_add(struct perf_event *event, int flags) 9746 { 9747 if (flags & PERF_EF_START) 9748 task_clock_event_start(event, flags); 9749 perf_event_update_userpage(event); 9750 9751 return 0; 9752 } 9753 9754 static void task_clock_event_del(struct perf_event *event, int flags) 9755 { 9756 task_clock_event_stop(event, PERF_EF_UPDATE); 9757 } 9758 9759 static void task_clock_event_read(struct perf_event *event) 9760 { 9761 u64 now = perf_clock(); 9762 u64 delta = now - event->ctx->timestamp; 9763 u64 time = event->ctx->time + delta; 9764 9765 task_clock_event_update(event, time); 9766 } 9767 9768 static int task_clock_event_init(struct perf_event *event) 9769 { 9770 if (event->attr.type != PERF_TYPE_SOFTWARE) 9771 return -ENOENT; 9772 9773 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK) 9774 return -ENOENT; 9775 9776 /* 9777 * no branch sampling for software events 9778 */ 9779 if (has_branch_stack(event)) 9780 return -EOPNOTSUPP; 9781 9782 perf_swevent_init_hrtimer(event); 9783 9784 return 0; 9785 } 9786 9787 static struct pmu perf_task_clock = { 9788 .task_ctx_nr = perf_sw_context, 9789 9790 .capabilities = PERF_PMU_CAP_NO_NMI, 9791 9792 .event_init = task_clock_event_init, 9793 .add = task_clock_event_add, 9794 .del = task_clock_event_del, 9795 .start = task_clock_event_start, 9796 .stop = task_clock_event_stop, 9797 .read = task_clock_event_read, 9798 }; 9799 9800 static void perf_pmu_nop_void(struct pmu *pmu) 9801 { 9802 } 9803 9804 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags) 9805 { 9806 } 9807 9808 static int perf_pmu_nop_int(struct pmu *pmu) 9809 { 9810 return 0; 9811 } 9812 9813 static int perf_event_nop_int(struct perf_event *event, u64 value) 9814 { 9815 return 0; 9816 } 9817 9818 static DEFINE_PER_CPU(unsigned int, nop_txn_flags); 9819 9820 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags) 9821 { 9822 __this_cpu_write(nop_txn_flags, flags); 9823 9824 if (flags & ~PERF_PMU_TXN_ADD) 9825 return; 9826 9827 perf_pmu_disable(pmu); 9828 } 9829 9830 static int perf_pmu_commit_txn(struct pmu *pmu) 9831 { 9832 unsigned int flags = __this_cpu_read(nop_txn_flags); 9833 9834 __this_cpu_write(nop_txn_flags, 0); 9835 9836 if (flags & ~PERF_PMU_TXN_ADD) 9837 return 0; 9838 9839 perf_pmu_enable(pmu); 9840 return 0; 9841 } 9842 9843 static void perf_pmu_cancel_txn(struct pmu *pmu) 9844 { 9845 unsigned int flags = __this_cpu_read(nop_txn_flags); 9846 9847 __this_cpu_write(nop_txn_flags, 0); 9848 9849 if (flags & ~PERF_PMU_TXN_ADD) 9850 return; 9851 9852 perf_pmu_enable(pmu); 9853 } 9854 9855 static int perf_event_idx_default(struct perf_event *event) 9856 { 9857 return 0; 9858 } 9859 9860 /* 9861 * Ensures all contexts with the same task_ctx_nr have the same 9862 * pmu_cpu_context too. 9863 */ 9864 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn) 9865 { 9866 struct pmu *pmu; 9867 9868 if (ctxn < 0) 9869 return NULL; 9870 9871 list_for_each_entry(pmu, &pmus, entry) { 9872 if (pmu->task_ctx_nr == ctxn) 9873 return pmu->pmu_cpu_context; 9874 } 9875 9876 return NULL; 9877 } 9878 9879 static void free_pmu_context(struct pmu *pmu) 9880 { 9881 /* 9882 * Static contexts such as perf_sw_context have a global lifetime 9883 * and may be shared between different PMUs. Avoid freeing them 9884 * when a single PMU is going away. 9885 */ 9886 if (pmu->task_ctx_nr > perf_invalid_context) 9887 return; 9888 9889 free_percpu(pmu->pmu_cpu_context); 9890 } 9891 9892 /* 9893 * Let userspace know that this PMU supports address range filtering: 9894 */ 9895 static ssize_t nr_addr_filters_show(struct device *dev, 9896 struct device_attribute *attr, 9897 char *page) 9898 { 9899 struct pmu *pmu = dev_get_drvdata(dev); 9900 9901 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters); 9902 } 9903 DEVICE_ATTR_RO(nr_addr_filters); 9904 9905 static struct idr pmu_idr; 9906 9907 static ssize_t 9908 type_show(struct device *dev, struct device_attribute *attr, char *page) 9909 { 9910 struct pmu *pmu = dev_get_drvdata(dev); 9911 9912 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type); 9913 } 9914 static DEVICE_ATTR_RO(type); 9915 9916 static ssize_t 9917 perf_event_mux_interval_ms_show(struct device *dev, 9918 struct device_attribute *attr, 9919 char *page) 9920 { 9921 struct pmu *pmu = dev_get_drvdata(dev); 9922 9923 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms); 9924 } 9925 9926 static DEFINE_MUTEX(mux_interval_mutex); 9927 9928 static ssize_t 9929 perf_event_mux_interval_ms_store(struct device *dev, 9930 struct device_attribute *attr, 9931 const char *buf, size_t count) 9932 { 9933 struct pmu *pmu = dev_get_drvdata(dev); 9934 int timer, cpu, ret; 9935 9936 ret = kstrtoint(buf, 0, &timer); 9937 if (ret) 9938 return ret; 9939 9940 if (timer < 1) 9941 return -EINVAL; 9942 9943 /* same value, noting to do */ 9944 if (timer == pmu->hrtimer_interval_ms) 9945 return count; 9946 9947 mutex_lock(&mux_interval_mutex); 9948 pmu->hrtimer_interval_ms = timer; 9949 9950 /* update all cpuctx for this PMU */ 9951 cpus_read_lock(); 9952 for_each_online_cpu(cpu) { 9953 struct perf_cpu_context *cpuctx; 9954 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 9955 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer); 9956 9957 cpu_function_call(cpu, 9958 (remote_function_f)perf_mux_hrtimer_restart, cpuctx); 9959 } 9960 cpus_read_unlock(); 9961 mutex_unlock(&mux_interval_mutex); 9962 9963 return count; 9964 } 9965 static DEVICE_ATTR_RW(perf_event_mux_interval_ms); 9966 9967 static struct attribute *pmu_dev_attrs[] = { 9968 &dev_attr_type.attr, 9969 &dev_attr_perf_event_mux_interval_ms.attr, 9970 NULL, 9971 }; 9972 ATTRIBUTE_GROUPS(pmu_dev); 9973 9974 static int pmu_bus_running; 9975 static struct bus_type pmu_bus = { 9976 .name = "event_source", 9977 .dev_groups = pmu_dev_groups, 9978 }; 9979 9980 static void pmu_dev_release(struct device *dev) 9981 { 9982 kfree(dev); 9983 } 9984 9985 static int pmu_dev_alloc(struct pmu *pmu) 9986 { 9987 int ret = -ENOMEM; 9988 9989 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL); 9990 if (!pmu->dev) 9991 goto out; 9992 9993 pmu->dev->groups = pmu->attr_groups; 9994 device_initialize(pmu->dev); 9995 ret = dev_set_name(pmu->dev, "%s", pmu->name); 9996 if (ret) 9997 goto free_dev; 9998 9999 dev_set_drvdata(pmu->dev, pmu); 10000 pmu->dev->bus = &pmu_bus; 10001 pmu->dev->release = pmu_dev_release; 10002 ret = device_add(pmu->dev); 10003 if (ret) 10004 goto free_dev; 10005 10006 /* For PMUs with address filters, throw in an extra attribute: */ 10007 if (pmu->nr_addr_filters) 10008 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters); 10009 10010 if (ret) 10011 goto del_dev; 10012 10013 if (pmu->attr_update) 10014 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update); 10015 10016 if (ret) 10017 goto del_dev; 10018 10019 out: 10020 return ret; 10021 10022 del_dev: 10023 device_del(pmu->dev); 10024 10025 free_dev: 10026 put_device(pmu->dev); 10027 goto out; 10028 } 10029 10030 static struct lock_class_key cpuctx_mutex; 10031 static struct lock_class_key cpuctx_lock; 10032 10033 int perf_pmu_register(struct pmu *pmu, const char *name, int type) 10034 { 10035 int cpu, ret; 10036 10037 mutex_lock(&pmus_lock); 10038 ret = -ENOMEM; 10039 pmu->pmu_disable_count = alloc_percpu(int); 10040 if (!pmu->pmu_disable_count) 10041 goto unlock; 10042 10043 pmu->type = -1; 10044 if (!name) 10045 goto skip_type; 10046 pmu->name = name; 10047 10048 if (type < 0) { 10049 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL); 10050 if (type < 0) { 10051 ret = type; 10052 goto free_pdc; 10053 } 10054 } 10055 pmu->type = type; 10056 10057 if (pmu_bus_running) { 10058 ret = pmu_dev_alloc(pmu); 10059 if (ret) 10060 goto free_idr; 10061 } 10062 10063 skip_type: 10064 if (pmu->task_ctx_nr == perf_hw_context) { 10065 static int hw_context_taken = 0; 10066 10067 /* 10068 * Other than systems with heterogeneous CPUs, it never makes 10069 * sense for two PMUs to share perf_hw_context. PMUs which are 10070 * uncore must use perf_invalid_context. 10071 */ 10072 if (WARN_ON_ONCE(hw_context_taken && 10073 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS))) 10074 pmu->task_ctx_nr = perf_invalid_context; 10075 10076 hw_context_taken = 1; 10077 } 10078 10079 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr); 10080 if (pmu->pmu_cpu_context) 10081 goto got_cpu_context; 10082 10083 ret = -ENOMEM; 10084 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context); 10085 if (!pmu->pmu_cpu_context) 10086 goto free_dev; 10087 10088 for_each_possible_cpu(cpu) { 10089 struct perf_cpu_context *cpuctx; 10090 10091 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 10092 __perf_event_init_context(&cpuctx->ctx); 10093 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex); 10094 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock); 10095 cpuctx->ctx.pmu = pmu; 10096 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask); 10097 10098 __perf_mux_hrtimer_init(cpuctx, cpu); 10099 } 10100 10101 got_cpu_context: 10102 if (!pmu->start_txn) { 10103 if (pmu->pmu_enable) { 10104 /* 10105 * If we have pmu_enable/pmu_disable calls, install 10106 * transaction stubs that use that to try and batch 10107 * hardware accesses. 10108 */ 10109 pmu->start_txn = perf_pmu_start_txn; 10110 pmu->commit_txn = perf_pmu_commit_txn; 10111 pmu->cancel_txn = perf_pmu_cancel_txn; 10112 } else { 10113 pmu->start_txn = perf_pmu_nop_txn; 10114 pmu->commit_txn = perf_pmu_nop_int; 10115 pmu->cancel_txn = perf_pmu_nop_void; 10116 } 10117 } 10118 10119 if (!pmu->pmu_enable) { 10120 pmu->pmu_enable = perf_pmu_nop_void; 10121 pmu->pmu_disable = perf_pmu_nop_void; 10122 } 10123 10124 if (!pmu->check_period) 10125 pmu->check_period = perf_event_nop_int; 10126 10127 if (!pmu->event_idx) 10128 pmu->event_idx = perf_event_idx_default; 10129 10130 list_add_rcu(&pmu->entry, &pmus); 10131 atomic_set(&pmu->exclusive_cnt, 0); 10132 ret = 0; 10133 unlock: 10134 mutex_unlock(&pmus_lock); 10135 10136 return ret; 10137 10138 free_dev: 10139 device_del(pmu->dev); 10140 put_device(pmu->dev); 10141 10142 free_idr: 10143 if (pmu->type >= PERF_TYPE_MAX) 10144 idr_remove(&pmu_idr, pmu->type); 10145 10146 free_pdc: 10147 free_percpu(pmu->pmu_disable_count); 10148 goto unlock; 10149 } 10150 EXPORT_SYMBOL_GPL(perf_pmu_register); 10151 10152 void perf_pmu_unregister(struct pmu *pmu) 10153 { 10154 mutex_lock(&pmus_lock); 10155 list_del_rcu(&pmu->entry); 10156 10157 /* 10158 * We dereference the pmu list under both SRCU and regular RCU, so 10159 * synchronize against both of those. 10160 */ 10161 synchronize_srcu(&pmus_srcu); 10162 synchronize_rcu(); 10163 10164 free_percpu(pmu->pmu_disable_count); 10165 if (pmu->type >= PERF_TYPE_MAX) 10166 idr_remove(&pmu_idr, pmu->type); 10167 if (pmu_bus_running) { 10168 if (pmu->nr_addr_filters) 10169 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters); 10170 device_del(pmu->dev); 10171 put_device(pmu->dev); 10172 } 10173 free_pmu_context(pmu); 10174 mutex_unlock(&pmus_lock); 10175 } 10176 EXPORT_SYMBOL_GPL(perf_pmu_unregister); 10177 10178 static inline bool has_extended_regs(struct perf_event *event) 10179 { 10180 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) || 10181 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK); 10182 } 10183 10184 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event) 10185 { 10186 struct perf_event_context *ctx = NULL; 10187 int ret; 10188 10189 if (!try_module_get(pmu->module)) 10190 return -ENODEV; 10191 10192 /* 10193 * A number of pmu->event_init() methods iterate the sibling_list to, 10194 * for example, validate if the group fits on the PMU. Therefore, 10195 * if this is a sibling event, acquire the ctx->mutex to protect 10196 * the sibling_list. 10197 */ 10198 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) { 10199 /* 10200 * This ctx->mutex can nest when we're called through 10201 * inheritance. See the perf_event_ctx_lock_nested() comment. 10202 */ 10203 ctx = perf_event_ctx_lock_nested(event->group_leader, 10204 SINGLE_DEPTH_NESTING); 10205 BUG_ON(!ctx); 10206 } 10207 10208 event->pmu = pmu; 10209 ret = pmu->event_init(event); 10210 10211 if (ctx) 10212 perf_event_ctx_unlock(event->group_leader, ctx); 10213 10214 if (!ret) { 10215 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) && 10216 has_extended_regs(event)) 10217 ret = -EOPNOTSUPP; 10218 10219 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE && 10220 event_has_any_exclude_flag(event)) 10221 ret = -EINVAL; 10222 10223 if (ret && event->destroy) 10224 event->destroy(event); 10225 } 10226 10227 if (ret) 10228 module_put(pmu->module); 10229 10230 return ret; 10231 } 10232 10233 static struct pmu *perf_init_event(struct perf_event *event) 10234 { 10235 struct pmu *pmu; 10236 int idx; 10237 int ret; 10238 10239 idx = srcu_read_lock(&pmus_srcu); 10240 10241 /* Try parent's PMU first: */ 10242 if (event->parent && event->parent->pmu) { 10243 pmu = event->parent->pmu; 10244 ret = perf_try_init_event(pmu, event); 10245 if (!ret) 10246 goto unlock; 10247 } 10248 10249 rcu_read_lock(); 10250 pmu = idr_find(&pmu_idr, event->attr.type); 10251 rcu_read_unlock(); 10252 if (pmu) { 10253 ret = perf_try_init_event(pmu, event); 10254 if (ret) 10255 pmu = ERR_PTR(ret); 10256 goto unlock; 10257 } 10258 10259 list_for_each_entry_rcu(pmu, &pmus, entry) { 10260 ret = perf_try_init_event(pmu, event); 10261 if (!ret) 10262 goto unlock; 10263 10264 if (ret != -ENOENT) { 10265 pmu = ERR_PTR(ret); 10266 goto unlock; 10267 } 10268 } 10269 pmu = ERR_PTR(-ENOENT); 10270 unlock: 10271 srcu_read_unlock(&pmus_srcu, idx); 10272 10273 return pmu; 10274 } 10275 10276 static void attach_sb_event(struct perf_event *event) 10277 { 10278 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu); 10279 10280 raw_spin_lock(&pel->lock); 10281 list_add_rcu(&event->sb_list, &pel->list); 10282 raw_spin_unlock(&pel->lock); 10283 } 10284 10285 /* 10286 * We keep a list of all !task (and therefore per-cpu) events 10287 * that need to receive side-band records. 10288 * 10289 * This avoids having to scan all the various PMU per-cpu contexts 10290 * looking for them. 10291 */ 10292 static void account_pmu_sb_event(struct perf_event *event) 10293 { 10294 if (is_sb_event(event)) 10295 attach_sb_event(event); 10296 } 10297 10298 static void account_event_cpu(struct perf_event *event, int cpu) 10299 { 10300 if (event->parent) 10301 return; 10302 10303 if (is_cgroup_event(event)) 10304 atomic_inc(&per_cpu(perf_cgroup_events, cpu)); 10305 } 10306 10307 /* Freq events need the tick to stay alive (see perf_event_task_tick). */ 10308 static void account_freq_event_nohz(void) 10309 { 10310 #ifdef CONFIG_NO_HZ_FULL 10311 /* Lock so we don't race with concurrent unaccount */ 10312 spin_lock(&nr_freq_lock); 10313 if (atomic_inc_return(&nr_freq_events) == 1) 10314 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS); 10315 spin_unlock(&nr_freq_lock); 10316 #endif 10317 } 10318 10319 static void account_freq_event(void) 10320 { 10321 if (tick_nohz_full_enabled()) 10322 account_freq_event_nohz(); 10323 else 10324 atomic_inc(&nr_freq_events); 10325 } 10326 10327 10328 static void account_event(struct perf_event *event) 10329 { 10330 bool inc = false; 10331 10332 if (event->parent) 10333 return; 10334 10335 if (event->attach_state & PERF_ATTACH_TASK) 10336 inc = true; 10337 if (event->attr.mmap || event->attr.mmap_data) 10338 atomic_inc(&nr_mmap_events); 10339 if (event->attr.comm) 10340 atomic_inc(&nr_comm_events); 10341 if (event->attr.namespaces) 10342 atomic_inc(&nr_namespaces_events); 10343 if (event->attr.task) 10344 atomic_inc(&nr_task_events); 10345 if (event->attr.freq) 10346 account_freq_event(); 10347 if (event->attr.context_switch) { 10348 atomic_inc(&nr_switch_events); 10349 inc = true; 10350 } 10351 if (has_branch_stack(event)) 10352 inc = true; 10353 if (is_cgroup_event(event)) 10354 inc = true; 10355 if (event->attr.ksymbol) 10356 atomic_inc(&nr_ksymbol_events); 10357 if (event->attr.bpf_event) 10358 atomic_inc(&nr_bpf_events); 10359 10360 if (inc) { 10361 /* 10362 * We need the mutex here because static_branch_enable() 10363 * must complete *before* the perf_sched_count increment 10364 * becomes visible. 10365 */ 10366 if (atomic_inc_not_zero(&perf_sched_count)) 10367 goto enabled; 10368 10369 mutex_lock(&perf_sched_mutex); 10370 if (!atomic_read(&perf_sched_count)) { 10371 static_branch_enable(&perf_sched_events); 10372 /* 10373 * Guarantee that all CPUs observe they key change and 10374 * call the perf scheduling hooks before proceeding to 10375 * install events that need them. 10376 */ 10377 synchronize_rcu(); 10378 } 10379 /* 10380 * Now that we have waited for the sync_sched(), allow further 10381 * increments to by-pass the mutex. 10382 */ 10383 atomic_inc(&perf_sched_count); 10384 mutex_unlock(&perf_sched_mutex); 10385 } 10386 enabled: 10387 10388 account_event_cpu(event, event->cpu); 10389 10390 account_pmu_sb_event(event); 10391 } 10392 10393 /* 10394 * Allocate and initialize an event structure 10395 */ 10396 static struct perf_event * 10397 perf_event_alloc(struct perf_event_attr *attr, int cpu, 10398 struct task_struct *task, 10399 struct perf_event *group_leader, 10400 struct perf_event *parent_event, 10401 perf_overflow_handler_t overflow_handler, 10402 void *context, int cgroup_fd) 10403 { 10404 struct pmu *pmu; 10405 struct perf_event *event; 10406 struct hw_perf_event *hwc; 10407 long err = -EINVAL; 10408 10409 if ((unsigned)cpu >= nr_cpu_ids) { 10410 if (!task || cpu != -1) 10411 return ERR_PTR(-EINVAL); 10412 } 10413 10414 event = kzalloc(sizeof(*event), GFP_KERNEL); 10415 if (!event) 10416 return ERR_PTR(-ENOMEM); 10417 10418 /* 10419 * Single events are their own group leaders, with an 10420 * empty sibling list: 10421 */ 10422 if (!group_leader) 10423 group_leader = event; 10424 10425 mutex_init(&event->child_mutex); 10426 INIT_LIST_HEAD(&event->child_list); 10427 10428 INIT_LIST_HEAD(&event->event_entry); 10429 INIT_LIST_HEAD(&event->sibling_list); 10430 INIT_LIST_HEAD(&event->active_list); 10431 init_event_group(event); 10432 INIT_LIST_HEAD(&event->rb_entry); 10433 INIT_LIST_HEAD(&event->active_entry); 10434 INIT_LIST_HEAD(&event->addr_filters.list); 10435 INIT_HLIST_NODE(&event->hlist_entry); 10436 10437 10438 init_waitqueue_head(&event->waitq); 10439 event->pending_disable = -1; 10440 init_irq_work(&event->pending, perf_pending_event); 10441 10442 mutex_init(&event->mmap_mutex); 10443 raw_spin_lock_init(&event->addr_filters.lock); 10444 10445 atomic_long_set(&event->refcount, 1); 10446 event->cpu = cpu; 10447 event->attr = *attr; 10448 event->group_leader = group_leader; 10449 event->pmu = NULL; 10450 event->oncpu = -1; 10451 10452 event->parent = parent_event; 10453 10454 event->ns = get_pid_ns(task_active_pid_ns(current)); 10455 event->id = atomic64_inc_return(&perf_event_id); 10456 10457 event->state = PERF_EVENT_STATE_INACTIVE; 10458 10459 if (task) { 10460 event->attach_state = PERF_ATTACH_TASK; 10461 /* 10462 * XXX pmu::event_init needs to know what task to account to 10463 * and we cannot use the ctx information because we need the 10464 * pmu before we get a ctx. 10465 */ 10466 event->hw.target = get_task_struct(task); 10467 } 10468 10469 event->clock = &local_clock; 10470 if (parent_event) 10471 event->clock = parent_event->clock; 10472 10473 if (!overflow_handler && parent_event) { 10474 overflow_handler = parent_event->overflow_handler; 10475 context = parent_event->overflow_handler_context; 10476 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING) 10477 if (overflow_handler == bpf_overflow_handler) { 10478 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog); 10479 10480 if (IS_ERR(prog)) { 10481 err = PTR_ERR(prog); 10482 goto err_ns; 10483 } 10484 event->prog = prog; 10485 event->orig_overflow_handler = 10486 parent_event->orig_overflow_handler; 10487 } 10488 #endif 10489 } 10490 10491 if (overflow_handler) { 10492 event->overflow_handler = overflow_handler; 10493 event->overflow_handler_context = context; 10494 } else if (is_write_backward(event)){ 10495 event->overflow_handler = perf_event_output_backward; 10496 event->overflow_handler_context = NULL; 10497 } else { 10498 event->overflow_handler = perf_event_output_forward; 10499 event->overflow_handler_context = NULL; 10500 } 10501 10502 perf_event__state_init(event); 10503 10504 pmu = NULL; 10505 10506 hwc = &event->hw; 10507 hwc->sample_period = attr->sample_period; 10508 if (attr->freq && attr->sample_freq) 10509 hwc->sample_period = 1; 10510 hwc->last_period = hwc->sample_period; 10511 10512 local64_set(&hwc->period_left, hwc->sample_period); 10513 10514 /* 10515 * We currently do not support PERF_SAMPLE_READ on inherited events. 10516 * See perf_output_read(). 10517 */ 10518 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ)) 10519 goto err_ns; 10520 10521 if (!has_branch_stack(event)) 10522 event->attr.branch_sample_type = 0; 10523 10524 if (cgroup_fd != -1) { 10525 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader); 10526 if (err) 10527 goto err_ns; 10528 } 10529 10530 pmu = perf_init_event(event); 10531 if (IS_ERR(pmu)) { 10532 err = PTR_ERR(pmu); 10533 goto err_ns; 10534 } 10535 10536 if (event->attr.aux_output && 10537 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) { 10538 err = -EOPNOTSUPP; 10539 goto err_pmu; 10540 } 10541 10542 err = exclusive_event_init(event); 10543 if (err) 10544 goto err_pmu; 10545 10546 if (has_addr_filter(event)) { 10547 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters, 10548 sizeof(struct perf_addr_filter_range), 10549 GFP_KERNEL); 10550 if (!event->addr_filter_ranges) { 10551 err = -ENOMEM; 10552 goto err_per_task; 10553 } 10554 10555 /* 10556 * Clone the parent's vma offsets: they are valid until exec() 10557 * even if the mm is not shared with the parent. 10558 */ 10559 if (event->parent) { 10560 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 10561 10562 raw_spin_lock_irq(&ifh->lock); 10563 memcpy(event->addr_filter_ranges, 10564 event->parent->addr_filter_ranges, 10565 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range)); 10566 raw_spin_unlock_irq(&ifh->lock); 10567 } 10568 10569 /* force hw sync on the address filters */ 10570 event->addr_filters_gen = 1; 10571 } 10572 10573 if (!event->parent) { 10574 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) { 10575 err = get_callchain_buffers(attr->sample_max_stack); 10576 if (err) 10577 goto err_addr_filters; 10578 } 10579 } 10580 10581 /* symmetric to unaccount_event() in _free_event() */ 10582 account_event(event); 10583 10584 return event; 10585 10586 err_addr_filters: 10587 kfree(event->addr_filter_ranges); 10588 10589 err_per_task: 10590 exclusive_event_destroy(event); 10591 10592 err_pmu: 10593 if (event->destroy) 10594 event->destroy(event); 10595 module_put(pmu->module); 10596 err_ns: 10597 if (is_cgroup_event(event)) 10598 perf_detach_cgroup(event); 10599 if (event->ns) 10600 put_pid_ns(event->ns); 10601 if (event->hw.target) 10602 put_task_struct(event->hw.target); 10603 kfree(event); 10604 10605 return ERR_PTR(err); 10606 } 10607 10608 static int perf_copy_attr(struct perf_event_attr __user *uattr, 10609 struct perf_event_attr *attr) 10610 { 10611 u32 size; 10612 int ret; 10613 10614 /* Zero the full structure, so that a short copy will be nice. */ 10615 memset(attr, 0, sizeof(*attr)); 10616 10617 ret = get_user(size, &uattr->size); 10618 if (ret) 10619 return ret; 10620 10621 /* ABI compatibility quirk: */ 10622 if (!size) 10623 size = PERF_ATTR_SIZE_VER0; 10624 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE) 10625 goto err_size; 10626 10627 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size); 10628 if (ret) { 10629 if (ret == -E2BIG) 10630 goto err_size; 10631 return ret; 10632 } 10633 10634 attr->size = size; 10635 10636 if (attr->__reserved_1) 10637 return -EINVAL; 10638 10639 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1)) 10640 return -EINVAL; 10641 10642 if (attr->read_format & ~(PERF_FORMAT_MAX-1)) 10643 return -EINVAL; 10644 10645 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) { 10646 u64 mask = attr->branch_sample_type; 10647 10648 /* only using defined bits */ 10649 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1)) 10650 return -EINVAL; 10651 10652 /* at least one branch bit must be set */ 10653 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL)) 10654 return -EINVAL; 10655 10656 /* propagate priv level, when not set for branch */ 10657 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) { 10658 10659 /* exclude_kernel checked on syscall entry */ 10660 if (!attr->exclude_kernel) 10661 mask |= PERF_SAMPLE_BRANCH_KERNEL; 10662 10663 if (!attr->exclude_user) 10664 mask |= PERF_SAMPLE_BRANCH_USER; 10665 10666 if (!attr->exclude_hv) 10667 mask |= PERF_SAMPLE_BRANCH_HV; 10668 /* 10669 * adjust user setting (for HW filter setup) 10670 */ 10671 attr->branch_sample_type = mask; 10672 } 10673 /* privileged levels capture (kernel, hv): check permissions */ 10674 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM) 10675 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) 10676 return -EACCES; 10677 } 10678 10679 if (attr->sample_type & PERF_SAMPLE_REGS_USER) { 10680 ret = perf_reg_validate(attr->sample_regs_user); 10681 if (ret) 10682 return ret; 10683 } 10684 10685 if (attr->sample_type & PERF_SAMPLE_STACK_USER) { 10686 if (!arch_perf_have_user_stack_dump()) 10687 return -ENOSYS; 10688 10689 /* 10690 * We have __u32 type for the size, but so far 10691 * we can only use __u16 as maximum due to the 10692 * __u16 sample size limit. 10693 */ 10694 if (attr->sample_stack_user >= USHRT_MAX) 10695 return -EINVAL; 10696 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64))) 10697 return -EINVAL; 10698 } 10699 10700 if (!attr->sample_max_stack) 10701 attr->sample_max_stack = sysctl_perf_event_max_stack; 10702 10703 if (attr->sample_type & PERF_SAMPLE_REGS_INTR) 10704 ret = perf_reg_validate(attr->sample_regs_intr); 10705 out: 10706 return ret; 10707 10708 err_size: 10709 put_user(sizeof(*attr), &uattr->size); 10710 ret = -E2BIG; 10711 goto out; 10712 } 10713 10714 static int 10715 perf_event_set_output(struct perf_event *event, struct perf_event *output_event) 10716 { 10717 struct ring_buffer *rb = NULL; 10718 int ret = -EINVAL; 10719 10720 if (!output_event) 10721 goto set; 10722 10723 /* don't allow circular references */ 10724 if (event == output_event) 10725 goto out; 10726 10727 /* 10728 * Don't allow cross-cpu buffers 10729 */ 10730 if (output_event->cpu != event->cpu) 10731 goto out; 10732 10733 /* 10734 * If its not a per-cpu rb, it must be the same task. 10735 */ 10736 if (output_event->cpu == -1 && output_event->ctx != event->ctx) 10737 goto out; 10738 10739 /* 10740 * Mixing clocks in the same buffer is trouble you don't need. 10741 */ 10742 if (output_event->clock != event->clock) 10743 goto out; 10744 10745 /* 10746 * Either writing ring buffer from beginning or from end. 10747 * Mixing is not allowed. 10748 */ 10749 if (is_write_backward(output_event) != is_write_backward(event)) 10750 goto out; 10751 10752 /* 10753 * If both events generate aux data, they must be on the same PMU 10754 */ 10755 if (has_aux(event) && has_aux(output_event) && 10756 event->pmu != output_event->pmu) 10757 goto out; 10758 10759 set: 10760 mutex_lock(&event->mmap_mutex); 10761 /* Can't redirect output if we've got an active mmap() */ 10762 if (atomic_read(&event->mmap_count)) 10763 goto unlock; 10764 10765 if (output_event) { 10766 /* get the rb we want to redirect to */ 10767 rb = ring_buffer_get(output_event); 10768 if (!rb) 10769 goto unlock; 10770 } 10771 10772 ring_buffer_attach(event, rb); 10773 10774 ret = 0; 10775 unlock: 10776 mutex_unlock(&event->mmap_mutex); 10777 10778 out: 10779 return ret; 10780 } 10781 10782 static void mutex_lock_double(struct mutex *a, struct mutex *b) 10783 { 10784 if (b < a) 10785 swap(a, b); 10786 10787 mutex_lock(a); 10788 mutex_lock_nested(b, SINGLE_DEPTH_NESTING); 10789 } 10790 10791 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id) 10792 { 10793 bool nmi_safe = false; 10794 10795 switch (clk_id) { 10796 case CLOCK_MONOTONIC: 10797 event->clock = &ktime_get_mono_fast_ns; 10798 nmi_safe = true; 10799 break; 10800 10801 case CLOCK_MONOTONIC_RAW: 10802 event->clock = &ktime_get_raw_fast_ns; 10803 nmi_safe = true; 10804 break; 10805 10806 case CLOCK_REALTIME: 10807 event->clock = &ktime_get_real_ns; 10808 break; 10809 10810 case CLOCK_BOOTTIME: 10811 event->clock = &ktime_get_boottime_ns; 10812 break; 10813 10814 case CLOCK_TAI: 10815 event->clock = &ktime_get_clocktai_ns; 10816 break; 10817 10818 default: 10819 return -EINVAL; 10820 } 10821 10822 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI)) 10823 return -EINVAL; 10824 10825 return 0; 10826 } 10827 10828 /* 10829 * Variation on perf_event_ctx_lock_nested(), except we take two context 10830 * mutexes. 10831 */ 10832 static struct perf_event_context * 10833 __perf_event_ctx_lock_double(struct perf_event *group_leader, 10834 struct perf_event_context *ctx) 10835 { 10836 struct perf_event_context *gctx; 10837 10838 again: 10839 rcu_read_lock(); 10840 gctx = READ_ONCE(group_leader->ctx); 10841 if (!refcount_inc_not_zero(&gctx->refcount)) { 10842 rcu_read_unlock(); 10843 goto again; 10844 } 10845 rcu_read_unlock(); 10846 10847 mutex_lock_double(&gctx->mutex, &ctx->mutex); 10848 10849 if (group_leader->ctx != gctx) { 10850 mutex_unlock(&ctx->mutex); 10851 mutex_unlock(&gctx->mutex); 10852 put_ctx(gctx); 10853 goto again; 10854 } 10855 10856 return gctx; 10857 } 10858 10859 /** 10860 * sys_perf_event_open - open a performance event, associate it to a task/cpu 10861 * 10862 * @attr_uptr: event_id type attributes for monitoring/sampling 10863 * @pid: target pid 10864 * @cpu: target cpu 10865 * @group_fd: group leader event fd 10866 */ 10867 SYSCALL_DEFINE5(perf_event_open, 10868 struct perf_event_attr __user *, attr_uptr, 10869 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags) 10870 { 10871 struct perf_event *group_leader = NULL, *output_event = NULL; 10872 struct perf_event *event, *sibling; 10873 struct perf_event_attr attr; 10874 struct perf_event_context *ctx, *uninitialized_var(gctx); 10875 struct file *event_file = NULL; 10876 struct fd group = {NULL, 0}; 10877 struct task_struct *task = NULL; 10878 struct pmu *pmu; 10879 int event_fd; 10880 int move_group = 0; 10881 int err; 10882 int f_flags = O_RDWR; 10883 int cgroup_fd = -1; 10884 10885 /* for future expandability... */ 10886 if (flags & ~PERF_FLAG_ALL) 10887 return -EINVAL; 10888 10889 err = perf_copy_attr(attr_uptr, &attr); 10890 if (err) 10891 return err; 10892 10893 if (!attr.exclude_kernel) { 10894 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) 10895 return -EACCES; 10896 } 10897 10898 if (attr.namespaces) { 10899 if (!capable(CAP_SYS_ADMIN)) 10900 return -EACCES; 10901 } 10902 10903 if (attr.freq) { 10904 if (attr.sample_freq > sysctl_perf_event_sample_rate) 10905 return -EINVAL; 10906 } else { 10907 if (attr.sample_period & (1ULL << 63)) 10908 return -EINVAL; 10909 } 10910 10911 /* Only privileged users can get physical addresses */ 10912 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) && 10913 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) 10914 return -EACCES; 10915 10916 err = security_locked_down(LOCKDOWN_PERF); 10917 if (err && (attr.sample_type & PERF_SAMPLE_REGS_INTR)) 10918 /* REGS_INTR can leak data, lockdown must prevent this */ 10919 return err; 10920 10921 err = 0; 10922 10923 /* 10924 * In cgroup mode, the pid argument is used to pass the fd 10925 * opened to the cgroup directory in cgroupfs. The cpu argument 10926 * designates the cpu on which to monitor threads from that 10927 * cgroup. 10928 */ 10929 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1)) 10930 return -EINVAL; 10931 10932 if (flags & PERF_FLAG_FD_CLOEXEC) 10933 f_flags |= O_CLOEXEC; 10934 10935 event_fd = get_unused_fd_flags(f_flags); 10936 if (event_fd < 0) 10937 return event_fd; 10938 10939 if (group_fd != -1) { 10940 err = perf_fget_light(group_fd, &group); 10941 if (err) 10942 goto err_fd; 10943 group_leader = group.file->private_data; 10944 if (flags & PERF_FLAG_FD_OUTPUT) 10945 output_event = group_leader; 10946 if (flags & PERF_FLAG_FD_NO_GROUP) 10947 group_leader = NULL; 10948 } 10949 10950 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) { 10951 task = find_lively_task_by_vpid(pid); 10952 if (IS_ERR(task)) { 10953 err = PTR_ERR(task); 10954 goto err_group_fd; 10955 } 10956 } 10957 10958 if (task && group_leader && 10959 group_leader->attr.inherit != attr.inherit) { 10960 err = -EINVAL; 10961 goto err_task; 10962 } 10963 10964 if (task) { 10965 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex); 10966 if (err) 10967 goto err_task; 10968 10969 /* 10970 * Reuse ptrace permission checks for now. 10971 * 10972 * We must hold cred_guard_mutex across this and any potential 10973 * perf_install_in_context() call for this new event to 10974 * serialize against exec() altering our credentials (and the 10975 * perf_event_exit_task() that could imply). 10976 */ 10977 err = -EACCES; 10978 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) 10979 goto err_cred; 10980 } 10981 10982 if (flags & PERF_FLAG_PID_CGROUP) 10983 cgroup_fd = pid; 10984 10985 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, 10986 NULL, NULL, cgroup_fd); 10987 if (IS_ERR(event)) { 10988 err = PTR_ERR(event); 10989 goto err_cred; 10990 } 10991 10992 if (is_sampling_event(event)) { 10993 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) { 10994 err = -EOPNOTSUPP; 10995 goto err_alloc; 10996 } 10997 } 10998 10999 /* 11000 * Special case software events and allow them to be part of 11001 * any hardware group. 11002 */ 11003 pmu = event->pmu; 11004 11005 if (attr.use_clockid) { 11006 err = perf_event_set_clock(event, attr.clockid); 11007 if (err) 11008 goto err_alloc; 11009 } 11010 11011 if (pmu->task_ctx_nr == perf_sw_context) 11012 event->event_caps |= PERF_EV_CAP_SOFTWARE; 11013 11014 if (group_leader) { 11015 if (is_software_event(event) && 11016 !in_software_context(group_leader)) { 11017 /* 11018 * If the event is a sw event, but the group_leader 11019 * is on hw context. 11020 * 11021 * Allow the addition of software events to hw 11022 * groups, this is safe because software events 11023 * never fail to schedule. 11024 */ 11025 pmu = group_leader->ctx->pmu; 11026 } else if (!is_software_event(event) && 11027 is_software_event(group_leader) && 11028 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) { 11029 /* 11030 * In case the group is a pure software group, and we 11031 * try to add a hardware event, move the whole group to 11032 * the hardware context. 11033 */ 11034 move_group = 1; 11035 } 11036 } 11037 11038 /* 11039 * Get the target context (task or percpu): 11040 */ 11041 ctx = find_get_context(pmu, task, event); 11042 if (IS_ERR(ctx)) { 11043 err = PTR_ERR(ctx); 11044 goto err_alloc; 11045 } 11046 11047 /* 11048 * Look up the group leader (we will attach this event to it): 11049 */ 11050 if (group_leader) { 11051 err = -EINVAL; 11052 11053 /* 11054 * Do not allow a recursive hierarchy (this new sibling 11055 * becoming part of another group-sibling): 11056 */ 11057 if (group_leader->group_leader != group_leader) 11058 goto err_context; 11059 11060 /* All events in a group should have the same clock */ 11061 if (group_leader->clock != event->clock) 11062 goto err_context; 11063 11064 /* 11065 * Make sure we're both events for the same CPU; 11066 * grouping events for different CPUs is broken; since 11067 * you can never concurrently schedule them anyhow. 11068 */ 11069 if (group_leader->cpu != event->cpu) 11070 goto err_context; 11071 11072 /* 11073 * Make sure we're both on the same task, or both 11074 * per-CPU events. 11075 */ 11076 if (group_leader->ctx->task != ctx->task) 11077 goto err_context; 11078 11079 /* 11080 * Do not allow to attach to a group in a different task 11081 * or CPU context. If we're moving SW events, we'll fix 11082 * this up later, so allow that. 11083 */ 11084 if (!move_group && group_leader->ctx != ctx) 11085 goto err_context; 11086 11087 /* 11088 * Only a group leader can be exclusive or pinned 11089 */ 11090 if (attr.exclusive || attr.pinned) 11091 goto err_context; 11092 } 11093 11094 if (output_event) { 11095 err = perf_event_set_output(event, output_event); 11096 if (err) 11097 goto err_context; 11098 } 11099 11100 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, 11101 f_flags); 11102 if (IS_ERR(event_file)) { 11103 err = PTR_ERR(event_file); 11104 event_file = NULL; 11105 goto err_context; 11106 } 11107 11108 if (move_group) { 11109 gctx = __perf_event_ctx_lock_double(group_leader, ctx); 11110 11111 if (gctx->task == TASK_TOMBSTONE) { 11112 err = -ESRCH; 11113 goto err_locked; 11114 } 11115 11116 /* 11117 * Check if we raced against another sys_perf_event_open() call 11118 * moving the software group underneath us. 11119 */ 11120 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) { 11121 /* 11122 * If someone moved the group out from under us, check 11123 * if this new event wound up on the same ctx, if so 11124 * its the regular !move_group case, otherwise fail. 11125 */ 11126 if (gctx != ctx) { 11127 err = -EINVAL; 11128 goto err_locked; 11129 } else { 11130 perf_event_ctx_unlock(group_leader, gctx); 11131 move_group = 0; 11132 } 11133 } 11134 11135 /* 11136 * Failure to create exclusive events returns -EBUSY. 11137 */ 11138 err = -EBUSY; 11139 if (!exclusive_event_installable(group_leader, ctx)) 11140 goto err_locked; 11141 11142 for_each_sibling_event(sibling, group_leader) { 11143 if (!exclusive_event_installable(sibling, ctx)) 11144 goto err_locked; 11145 } 11146 } else { 11147 mutex_lock(&ctx->mutex); 11148 } 11149 11150 if (ctx->task == TASK_TOMBSTONE) { 11151 err = -ESRCH; 11152 goto err_locked; 11153 } 11154 11155 if (!perf_event_validate_size(event)) { 11156 err = -E2BIG; 11157 goto err_locked; 11158 } 11159 11160 if (!task) { 11161 /* 11162 * Check if the @cpu we're creating an event for is online. 11163 * 11164 * We use the perf_cpu_context::ctx::mutex to serialize against 11165 * the hotplug notifiers. See perf_event_{init,exit}_cpu(). 11166 */ 11167 struct perf_cpu_context *cpuctx = 11168 container_of(ctx, struct perf_cpu_context, ctx); 11169 11170 if (!cpuctx->online) { 11171 err = -ENODEV; 11172 goto err_locked; 11173 } 11174 } 11175 11176 if (event->attr.aux_output && !perf_get_aux_event(event, group_leader)) 11177 goto err_locked; 11178 11179 /* 11180 * Must be under the same ctx::mutex as perf_install_in_context(), 11181 * because we need to serialize with concurrent event creation. 11182 */ 11183 if (!exclusive_event_installable(event, ctx)) { 11184 err = -EBUSY; 11185 goto err_locked; 11186 } 11187 11188 WARN_ON_ONCE(ctx->parent_ctx); 11189 11190 /* 11191 * This is the point on no return; we cannot fail hereafter. This is 11192 * where we start modifying current state. 11193 */ 11194 11195 if (move_group) { 11196 /* 11197 * See perf_event_ctx_lock() for comments on the details 11198 * of swizzling perf_event::ctx. 11199 */ 11200 perf_remove_from_context(group_leader, 0); 11201 put_ctx(gctx); 11202 11203 for_each_sibling_event(sibling, group_leader) { 11204 perf_remove_from_context(sibling, 0); 11205 put_ctx(gctx); 11206 } 11207 11208 /* 11209 * Wait for everybody to stop referencing the events through 11210 * the old lists, before installing it on new lists. 11211 */ 11212 synchronize_rcu(); 11213 11214 /* 11215 * Install the group siblings before the group leader. 11216 * 11217 * Because a group leader will try and install the entire group 11218 * (through the sibling list, which is still in-tact), we can 11219 * end up with siblings installed in the wrong context. 11220 * 11221 * By installing siblings first we NO-OP because they're not 11222 * reachable through the group lists. 11223 */ 11224 for_each_sibling_event(sibling, group_leader) { 11225 perf_event__state_init(sibling); 11226 perf_install_in_context(ctx, sibling, sibling->cpu); 11227 get_ctx(ctx); 11228 } 11229 11230 /* 11231 * Removing from the context ends up with disabled 11232 * event. What we want here is event in the initial 11233 * startup state, ready to be add into new context. 11234 */ 11235 perf_event__state_init(group_leader); 11236 perf_install_in_context(ctx, group_leader, group_leader->cpu); 11237 get_ctx(ctx); 11238 } 11239 11240 /* 11241 * Precalculate sample_data sizes; do while holding ctx::mutex such 11242 * that we're serialized against further additions and before 11243 * perf_install_in_context() which is the point the event is active and 11244 * can use these values. 11245 */ 11246 perf_event__header_size(event); 11247 perf_event__id_header_size(event); 11248 11249 event->owner = current; 11250 11251 perf_install_in_context(ctx, event, event->cpu); 11252 perf_unpin_context(ctx); 11253 11254 if (move_group) 11255 perf_event_ctx_unlock(group_leader, gctx); 11256 mutex_unlock(&ctx->mutex); 11257 11258 if (task) { 11259 mutex_unlock(&task->signal->cred_guard_mutex); 11260 put_task_struct(task); 11261 } 11262 11263 mutex_lock(¤t->perf_event_mutex); 11264 list_add_tail(&event->owner_entry, ¤t->perf_event_list); 11265 mutex_unlock(¤t->perf_event_mutex); 11266 11267 /* 11268 * Drop the reference on the group_event after placing the 11269 * new event on the sibling_list. This ensures destruction 11270 * of the group leader will find the pointer to itself in 11271 * perf_group_detach(). 11272 */ 11273 fdput(group); 11274 fd_install(event_fd, event_file); 11275 return event_fd; 11276 11277 err_locked: 11278 if (move_group) 11279 perf_event_ctx_unlock(group_leader, gctx); 11280 mutex_unlock(&ctx->mutex); 11281 /* err_file: */ 11282 fput(event_file); 11283 err_context: 11284 perf_unpin_context(ctx); 11285 put_ctx(ctx); 11286 err_alloc: 11287 /* 11288 * If event_file is set, the fput() above will have called ->release() 11289 * and that will take care of freeing the event. 11290 */ 11291 if (!event_file) 11292 free_event(event); 11293 err_cred: 11294 if (task) 11295 mutex_unlock(&task->signal->cred_guard_mutex); 11296 err_task: 11297 if (task) 11298 put_task_struct(task); 11299 err_group_fd: 11300 fdput(group); 11301 err_fd: 11302 put_unused_fd(event_fd); 11303 return err; 11304 } 11305 11306 /** 11307 * perf_event_create_kernel_counter 11308 * 11309 * @attr: attributes of the counter to create 11310 * @cpu: cpu in which the counter is bound 11311 * @task: task to profile (NULL for percpu) 11312 */ 11313 struct perf_event * 11314 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, 11315 struct task_struct *task, 11316 perf_overflow_handler_t overflow_handler, 11317 void *context) 11318 { 11319 struct perf_event_context *ctx; 11320 struct perf_event *event; 11321 int err; 11322 11323 /* 11324 * Get the target context (task or percpu): 11325 */ 11326 11327 event = perf_event_alloc(attr, cpu, task, NULL, NULL, 11328 overflow_handler, context, -1); 11329 if (IS_ERR(event)) { 11330 err = PTR_ERR(event); 11331 goto err; 11332 } 11333 11334 /* Mark owner so we could distinguish it from user events. */ 11335 event->owner = TASK_TOMBSTONE; 11336 11337 ctx = find_get_context(event->pmu, task, event); 11338 if (IS_ERR(ctx)) { 11339 err = PTR_ERR(ctx); 11340 goto err_free; 11341 } 11342 11343 WARN_ON_ONCE(ctx->parent_ctx); 11344 mutex_lock(&ctx->mutex); 11345 if (ctx->task == TASK_TOMBSTONE) { 11346 err = -ESRCH; 11347 goto err_unlock; 11348 } 11349 11350 if (!task) { 11351 /* 11352 * Check if the @cpu we're creating an event for is online. 11353 * 11354 * We use the perf_cpu_context::ctx::mutex to serialize against 11355 * the hotplug notifiers. See perf_event_{init,exit}_cpu(). 11356 */ 11357 struct perf_cpu_context *cpuctx = 11358 container_of(ctx, struct perf_cpu_context, ctx); 11359 if (!cpuctx->online) { 11360 err = -ENODEV; 11361 goto err_unlock; 11362 } 11363 } 11364 11365 if (!exclusive_event_installable(event, ctx)) { 11366 err = -EBUSY; 11367 goto err_unlock; 11368 } 11369 11370 perf_install_in_context(ctx, event, event->cpu); 11371 perf_unpin_context(ctx); 11372 mutex_unlock(&ctx->mutex); 11373 11374 return event; 11375 11376 err_unlock: 11377 mutex_unlock(&ctx->mutex); 11378 perf_unpin_context(ctx); 11379 put_ctx(ctx); 11380 err_free: 11381 free_event(event); 11382 err: 11383 return ERR_PTR(err); 11384 } 11385 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter); 11386 11387 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu) 11388 { 11389 struct perf_event_context *src_ctx; 11390 struct perf_event_context *dst_ctx; 11391 struct perf_event *event, *tmp; 11392 LIST_HEAD(events); 11393 11394 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx; 11395 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx; 11396 11397 /* 11398 * See perf_event_ctx_lock() for comments on the details 11399 * of swizzling perf_event::ctx. 11400 */ 11401 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex); 11402 list_for_each_entry_safe(event, tmp, &src_ctx->event_list, 11403 event_entry) { 11404 perf_remove_from_context(event, 0); 11405 unaccount_event_cpu(event, src_cpu); 11406 put_ctx(src_ctx); 11407 list_add(&event->migrate_entry, &events); 11408 } 11409 11410 /* 11411 * Wait for the events to quiesce before re-instating them. 11412 */ 11413 synchronize_rcu(); 11414 11415 /* 11416 * Re-instate events in 2 passes. 11417 * 11418 * Skip over group leaders and only install siblings on this first 11419 * pass, siblings will not get enabled without a leader, however a 11420 * leader will enable its siblings, even if those are still on the old 11421 * context. 11422 */ 11423 list_for_each_entry_safe(event, tmp, &events, migrate_entry) { 11424 if (event->group_leader == event) 11425 continue; 11426 11427 list_del(&event->migrate_entry); 11428 if (event->state >= PERF_EVENT_STATE_OFF) 11429 event->state = PERF_EVENT_STATE_INACTIVE; 11430 account_event_cpu(event, dst_cpu); 11431 perf_install_in_context(dst_ctx, event, dst_cpu); 11432 get_ctx(dst_ctx); 11433 } 11434 11435 /* 11436 * Once all the siblings are setup properly, install the group leaders 11437 * to make it go. 11438 */ 11439 list_for_each_entry_safe(event, tmp, &events, migrate_entry) { 11440 list_del(&event->migrate_entry); 11441 if (event->state >= PERF_EVENT_STATE_OFF) 11442 event->state = PERF_EVENT_STATE_INACTIVE; 11443 account_event_cpu(event, dst_cpu); 11444 perf_install_in_context(dst_ctx, event, dst_cpu); 11445 get_ctx(dst_ctx); 11446 } 11447 mutex_unlock(&dst_ctx->mutex); 11448 mutex_unlock(&src_ctx->mutex); 11449 } 11450 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context); 11451 11452 static void sync_child_event(struct perf_event *child_event, 11453 struct task_struct *child) 11454 { 11455 struct perf_event *parent_event = child_event->parent; 11456 u64 child_val; 11457 11458 if (child_event->attr.inherit_stat) 11459 perf_event_read_event(child_event, child); 11460 11461 child_val = perf_event_count(child_event); 11462 11463 /* 11464 * Add back the child's count to the parent's count: 11465 */ 11466 atomic64_add(child_val, &parent_event->child_count); 11467 atomic64_add(child_event->total_time_enabled, 11468 &parent_event->child_total_time_enabled); 11469 atomic64_add(child_event->total_time_running, 11470 &parent_event->child_total_time_running); 11471 } 11472 11473 static void 11474 perf_event_exit_event(struct perf_event *child_event, 11475 struct perf_event_context *child_ctx, 11476 struct task_struct *child) 11477 { 11478 struct perf_event *parent_event = child_event->parent; 11479 11480 /* 11481 * Do not destroy the 'original' grouping; because of the context 11482 * switch optimization the original events could've ended up in a 11483 * random child task. 11484 * 11485 * If we were to destroy the original group, all group related 11486 * operations would cease to function properly after this random 11487 * child dies. 11488 * 11489 * Do destroy all inherited groups, we don't care about those 11490 * and being thorough is better. 11491 */ 11492 raw_spin_lock_irq(&child_ctx->lock); 11493 WARN_ON_ONCE(child_ctx->is_active); 11494 11495 if (parent_event) 11496 perf_group_detach(child_event); 11497 list_del_event(child_event, child_ctx); 11498 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */ 11499 raw_spin_unlock_irq(&child_ctx->lock); 11500 11501 /* 11502 * Parent events are governed by their filedesc, retain them. 11503 */ 11504 if (!parent_event) { 11505 perf_event_wakeup(child_event); 11506 return; 11507 } 11508 /* 11509 * Child events can be cleaned up. 11510 */ 11511 11512 sync_child_event(child_event, child); 11513 11514 /* 11515 * Remove this event from the parent's list 11516 */ 11517 WARN_ON_ONCE(parent_event->ctx->parent_ctx); 11518 mutex_lock(&parent_event->child_mutex); 11519 list_del_init(&child_event->child_list); 11520 mutex_unlock(&parent_event->child_mutex); 11521 11522 /* 11523 * Kick perf_poll() for is_event_hup(). 11524 */ 11525 perf_event_wakeup(parent_event); 11526 free_event(child_event); 11527 put_event(parent_event); 11528 } 11529 11530 static void perf_event_exit_task_context(struct task_struct *child, int ctxn) 11531 { 11532 struct perf_event_context *child_ctx, *clone_ctx = NULL; 11533 struct perf_event *child_event, *next; 11534 11535 WARN_ON_ONCE(child != current); 11536 11537 child_ctx = perf_pin_task_context(child, ctxn); 11538 if (!child_ctx) 11539 return; 11540 11541 /* 11542 * In order to reduce the amount of tricky in ctx tear-down, we hold 11543 * ctx::mutex over the entire thing. This serializes against almost 11544 * everything that wants to access the ctx. 11545 * 11546 * The exception is sys_perf_event_open() / 11547 * perf_event_create_kernel_count() which does find_get_context() 11548 * without ctx::mutex (it cannot because of the move_group double mutex 11549 * lock thing). See the comments in perf_install_in_context(). 11550 */ 11551 mutex_lock(&child_ctx->mutex); 11552 11553 /* 11554 * In a single ctx::lock section, de-schedule the events and detach the 11555 * context from the task such that we cannot ever get it scheduled back 11556 * in. 11557 */ 11558 raw_spin_lock_irq(&child_ctx->lock); 11559 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL); 11560 11561 /* 11562 * Now that the context is inactive, destroy the task <-> ctx relation 11563 * and mark the context dead. 11564 */ 11565 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL); 11566 put_ctx(child_ctx); /* cannot be last */ 11567 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE); 11568 put_task_struct(current); /* cannot be last */ 11569 11570 clone_ctx = unclone_ctx(child_ctx); 11571 raw_spin_unlock_irq(&child_ctx->lock); 11572 11573 if (clone_ctx) 11574 put_ctx(clone_ctx); 11575 11576 /* 11577 * Report the task dead after unscheduling the events so that we 11578 * won't get any samples after PERF_RECORD_EXIT. We can however still 11579 * get a few PERF_RECORD_READ events. 11580 */ 11581 perf_event_task(child, child_ctx, 0); 11582 11583 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry) 11584 perf_event_exit_event(child_event, child_ctx, child); 11585 11586 mutex_unlock(&child_ctx->mutex); 11587 11588 put_ctx(child_ctx); 11589 } 11590 11591 /* 11592 * When a child task exits, feed back event values to parent events. 11593 * 11594 * Can be called with cred_guard_mutex held when called from 11595 * install_exec_creds(). 11596 */ 11597 void perf_event_exit_task(struct task_struct *child) 11598 { 11599 struct perf_event *event, *tmp; 11600 int ctxn; 11601 11602 mutex_lock(&child->perf_event_mutex); 11603 list_for_each_entry_safe(event, tmp, &child->perf_event_list, 11604 owner_entry) { 11605 list_del_init(&event->owner_entry); 11606 11607 /* 11608 * Ensure the list deletion is visible before we clear 11609 * the owner, closes a race against perf_release() where 11610 * we need to serialize on the owner->perf_event_mutex. 11611 */ 11612 smp_store_release(&event->owner, NULL); 11613 } 11614 mutex_unlock(&child->perf_event_mutex); 11615 11616 for_each_task_context_nr(ctxn) 11617 perf_event_exit_task_context(child, ctxn); 11618 11619 /* 11620 * The perf_event_exit_task_context calls perf_event_task 11621 * with child's task_ctx, which generates EXIT events for 11622 * child contexts and sets child->perf_event_ctxp[] to NULL. 11623 * At this point we need to send EXIT events to cpu contexts. 11624 */ 11625 perf_event_task(child, NULL, 0); 11626 } 11627 11628 static void perf_free_event(struct perf_event *event, 11629 struct perf_event_context *ctx) 11630 { 11631 struct perf_event *parent = event->parent; 11632 11633 if (WARN_ON_ONCE(!parent)) 11634 return; 11635 11636 mutex_lock(&parent->child_mutex); 11637 list_del_init(&event->child_list); 11638 mutex_unlock(&parent->child_mutex); 11639 11640 put_event(parent); 11641 11642 raw_spin_lock_irq(&ctx->lock); 11643 perf_group_detach(event); 11644 list_del_event(event, ctx); 11645 raw_spin_unlock_irq(&ctx->lock); 11646 free_event(event); 11647 } 11648 11649 /* 11650 * Free a context as created by inheritance by perf_event_init_task() below, 11651 * used by fork() in case of fail. 11652 * 11653 * Even though the task has never lived, the context and events have been 11654 * exposed through the child_list, so we must take care tearing it all down. 11655 */ 11656 void perf_event_free_task(struct task_struct *task) 11657 { 11658 struct perf_event_context *ctx; 11659 struct perf_event *event, *tmp; 11660 int ctxn; 11661 11662 for_each_task_context_nr(ctxn) { 11663 ctx = task->perf_event_ctxp[ctxn]; 11664 if (!ctx) 11665 continue; 11666 11667 mutex_lock(&ctx->mutex); 11668 raw_spin_lock_irq(&ctx->lock); 11669 /* 11670 * Destroy the task <-> ctx relation and mark the context dead. 11671 * 11672 * This is important because even though the task hasn't been 11673 * exposed yet the context has been (through child_list). 11674 */ 11675 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL); 11676 WRITE_ONCE(ctx->task, TASK_TOMBSTONE); 11677 put_task_struct(task); /* cannot be last */ 11678 raw_spin_unlock_irq(&ctx->lock); 11679 11680 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) 11681 perf_free_event(event, ctx); 11682 11683 mutex_unlock(&ctx->mutex); 11684 11685 /* 11686 * perf_event_release_kernel() could've stolen some of our 11687 * child events and still have them on its free_list. In that 11688 * case we must wait for these events to have been freed (in 11689 * particular all their references to this task must've been 11690 * dropped). 11691 * 11692 * Without this copy_process() will unconditionally free this 11693 * task (irrespective of its reference count) and 11694 * _free_event()'s put_task_struct(event->hw.target) will be a 11695 * use-after-free. 11696 * 11697 * Wait for all events to drop their context reference. 11698 */ 11699 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1); 11700 put_ctx(ctx); /* must be last */ 11701 } 11702 } 11703 11704 void perf_event_delayed_put(struct task_struct *task) 11705 { 11706 int ctxn; 11707 11708 for_each_task_context_nr(ctxn) 11709 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]); 11710 } 11711 11712 struct file *perf_event_get(unsigned int fd) 11713 { 11714 struct file *file = fget(fd); 11715 if (!file) 11716 return ERR_PTR(-EBADF); 11717 11718 if (file->f_op != &perf_fops) { 11719 fput(file); 11720 return ERR_PTR(-EBADF); 11721 } 11722 11723 return file; 11724 } 11725 11726 const struct perf_event *perf_get_event(struct file *file) 11727 { 11728 if (file->f_op != &perf_fops) 11729 return ERR_PTR(-EINVAL); 11730 11731 return file->private_data; 11732 } 11733 11734 const struct perf_event_attr *perf_event_attrs(struct perf_event *event) 11735 { 11736 if (!event) 11737 return ERR_PTR(-EINVAL); 11738 11739 return &event->attr; 11740 } 11741 11742 /* 11743 * Inherit an event from parent task to child task. 11744 * 11745 * Returns: 11746 * - valid pointer on success 11747 * - NULL for orphaned events 11748 * - IS_ERR() on error 11749 */ 11750 static struct perf_event * 11751 inherit_event(struct perf_event *parent_event, 11752 struct task_struct *parent, 11753 struct perf_event_context *parent_ctx, 11754 struct task_struct *child, 11755 struct perf_event *group_leader, 11756 struct perf_event_context *child_ctx) 11757 { 11758 enum perf_event_state parent_state = parent_event->state; 11759 struct perf_event *child_event; 11760 unsigned long flags; 11761 11762 /* 11763 * Instead of creating recursive hierarchies of events, 11764 * we link inherited events back to the original parent, 11765 * which has a filp for sure, which we use as the reference 11766 * count: 11767 */ 11768 if (parent_event->parent) 11769 parent_event = parent_event->parent; 11770 11771 child_event = perf_event_alloc(&parent_event->attr, 11772 parent_event->cpu, 11773 child, 11774 group_leader, parent_event, 11775 NULL, NULL, -1); 11776 if (IS_ERR(child_event)) 11777 return child_event; 11778 11779 11780 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) && 11781 !child_ctx->task_ctx_data) { 11782 struct pmu *pmu = child_event->pmu; 11783 11784 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size, 11785 GFP_KERNEL); 11786 if (!child_ctx->task_ctx_data) { 11787 free_event(child_event); 11788 return NULL; 11789 } 11790 } 11791 11792 /* 11793 * is_orphaned_event() and list_add_tail(&parent_event->child_list) 11794 * must be under the same lock in order to serialize against 11795 * perf_event_release_kernel(), such that either we must observe 11796 * is_orphaned_event() or they will observe us on the child_list. 11797 */ 11798 mutex_lock(&parent_event->child_mutex); 11799 if (is_orphaned_event(parent_event) || 11800 !atomic_long_inc_not_zero(&parent_event->refcount)) { 11801 mutex_unlock(&parent_event->child_mutex); 11802 /* task_ctx_data is freed with child_ctx */ 11803 free_event(child_event); 11804 return NULL; 11805 } 11806 11807 get_ctx(child_ctx); 11808 11809 /* 11810 * Make the child state follow the state of the parent event, 11811 * not its attr.disabled bit. We hold the parent's mutex, 11812 * so we won't race with perf_event_{en, dis}able_family. 11813 */ 11814 if (parent_state >= PERF_EVENT_STATE_INACTIVE) 11815 child_event->state = PERF_EVENT_STATE_INACTIVE; 11816 else 11817 child_event->state = PERF_EVENT_STATE_OFF; 11818 11819 if (parent_event->attr.freq) { 11820 u64 sample_period = parent_event->hw.sample_period; 11821 struct hw_perf_event *hwc = &child_event->hw; 11822 11823 hwc->sample_period = sample_period; 11824 hwc->last_period = sample_period; 11825 11826 local64_set(&hwc->period_left, sample_period); 11827 } 11828 11829 child_event->ctx = child_ctx; 11830 child_event->overflow_handler = parent_event->overflow_handler; 11831 child_event->overflow_handler_context 11832 = parent_event->overflow_handler_context; 11833 11834 /* 11835 * Precalculate sample_data sizes 11836 */ 11837 perf_event__header_size(child_event); 11838 perf_event__id_header_size(child_event); 11839 11840 /* 11841 * Link it up in the child's context: 11842 */ 11843 raw_spin_lock_irqsave(&child_ctx->lock, flags); 11844 add_event_to_ctx(child_event, child_ctx); 11845 raw_spin_unlock_irqrestore(&child_ctx->lock, flags); 11846 11847 /* 11848 * Link this into the parent event's child list 11849 */ 11850 list_add_tail(&child_event->child_list, &parent_event->child_list); 11851 mutex_unlock(&parent_event->child_mutex); 11852 11853 return child_event; 11854 } 11855 11856 /* 11857 * Inherits an event group. 11858 * 11859 * This will quietly suppress orphaned events; !inherit_event() is not an error. 11860 * This matches with perf_event_release_kernel() removing all child events. 11861 * 11862 * Returns: 11863 * - 0 on success 11864 * - <0 on error 11865 */ 11866 static int inherit_group(struct perf_event *parent_event, 11867 struct task_struct *parent, 11868 struct perf_event_context *parent_ctx, 11869 struct task_struct *child, 11870 struct perf_event_context *child_ctx) 11871 { 11872 struct perf_event *leader; 11873 struct perf_event *sub; 11874 struct perf_event *child_ctr; 11875 11876 leader = inherit_event(parent_event, parent, parent_ctx, 11877 child, NULL, child_ctx); 11878 if (IS_ERR(leader)) 11879 return PTR_ERR(leader); 11880 /* 11881 * @leader can be NULL here because of is_orphaned_event(). In this 11882 * case inherit_event() will create individual events, similar to what 11883 * perf_group_detach() would do anyway. 11884 */ 11885 for_each_sibling_event(sub, parent_event) { 11886 child_ctr = inherit_event(sub, parent, parent_ctx, 11887 child, leader, child_ctx); 11888 if (IS_ERR(child_ctr)) 11889 return PTR_ERR(child_ctr); 11890 11891 if (sub->aux_event == parent_event && 11892 !perf_get_aux_event(child_ctr, leader)) 11893 return -EINVAL; 11894 } 11895 return 0; 11896 } 11897 11898 /* 11899 * Creates the child task context and tries to inherit the event-group. 11900 * 11901 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave 11902 * inherited_all set when we 'fail' to inherit an orphaned event; this is 11903 * consistent with perf_event_release_kernel() removing all child events. 11904 * 11905 * Returns: 11906 * - 0 on success 11907 * - <0 on error 11908 */ 11909 static int 11910 inherit_task_group(struct perf_event *event, struct task_struct *parent, 11911 struct perf_event_context *parent_ctx, 11912 struct task_struct *child, int ctxn, 11913 int *inherited_all) 11914 { 11915 int ret; 11916 struct perf_event_context *child_ctx; 11917 11918 if (!event->attr.inherit) { 11919 *inherited_all = 0; 11920 return 0; 11921 } 11922 11923 child_ctx = child->perf_event_ctxp[ctxn]; 11924 if (!child_ctx) { 11925 /* 11926 * This is executed from the parent task context, so 11927 * inherit events that have been marked for cloning. 11928 * First allocate and initialize a context for the 11929 * child. 11930 */ 11931 child_ctx = alloc_perf_context(parent_ctx->pmu, child); 11932 if (!child_ctx) 11933 return -ENOMEM; 11934 11935 child->perf_event_ctxp[ctxn] = child_ctx; 11936 } 11937 11938 ret = inherit_group(event, parent, parent_ctx, 11939 child, child_ctx); 11940 11941 if (ret) 11942 *inherited_all = 0; 11943 11944 return ret; 11945 } 11946 11947 /* 11948 * Initialize the perf_event context in task_struct 11949 */ 11950 static int perf_event_init_context(struct task_struct *child, int ctxn) 11951 { 11952 struct perf_event_context *child_ctx, *parent_ctx; 11953 struct perf_event_context *cloned_ctx; 11954 struct perf_event *event; 11955 struct task_struct *parent = current; 11956 int inherited_all = 1; 11957 unsigned long flags; 11958 int ret = 0; 11959 11960 if (likely(!parent->perf_event_ctxp[ctxn])) 11961 return 0; 11962 11963 /* 11964 * If the parent's context is a clone, pin it so it won't get 11965 * swapped under us. 11966 */ 11967 parent_ctx = perf_pin_task_context(parent, ctxn); 11968 if (!parent_ctx) 11969 return 0; 11970 11971 /* 11972 * No need to check if parent_ctx != NULL here; since we saw 11973 * it non-NULL earlier, the only reason for it to become NULL 11974 * is if we exit, and since we're currently in the middle of 11975 * a fork we can't be exiting at the same time. 11976 */ 11977 11978 /* 11979 * Lock the parent list. No need to lock the child - not PID 11980 * hashed yet and not running, so nobody can access it. 11981 */ 11982 mutex_lock(&parent_ctx->mutex); 11983 11984 /* 11985 * We dont have to disable NMIs - we are only looking at 11986 * the list, not manipulating it: 11987 */ 11988 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) { 11989 ret = inherit_task_group(event, parent, parent_ctx, 11990 child, ctxn, &inherited_all); 11991 if (ret) 11992 goto out_unlock; 11993 } 11994 11995 /* 11996 * We can't hold ctx->lock when iterating the ->flexible_group list due 11997 * to allocations, but we need to prevent rotation because 11998 * rotate_ctx() will change the list from interrupt context. 11999 */ 12000 raw_spin_lock_irqsave(&parent_ctx->lock, flags); 12001 parent_ctx->rotate_disable = 1; 12002 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); 12003 12004 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) { 12005 ret = inherit_task_group(event, parent, parent_ctx, 12006 child, ctxn, &inherited_all); 12007 if (ret) 12008 goto out_unlock; 12009 } 12010 12011 raw_spin_lock_irqsave(&parent_ctx->lock, flags); 12012 parent_ctx->rotate_disable = 0; 12013 12014 child_ctx = child->perf_event_ctxp[ctxn]; 12015 12016 if (child_ctx && inherited_all) { 12017 /* 12018 * Mark the child context as a clone of the parent 12019 * context, or of whatever the parent is a clone of. 12020 * 12021 * Note that if the parent is a clone, the holding of 12022 * parent_ctx->lock avoids it from being uncloned. 12023 */ 12024 cloned_ctx = parent_ctx->parent_ctx; 12025 if (cloned_ctx) { 12026 child_ctx->parent_ctx = cloned_ctx; 12027 child_ctx->parent_gen = parent_ctx->parent_gen; 12028 } else { 12029 child_ctx->parent_ctx = parent_ctx; 12030 child_ctx->parent_gen = parent_ctx->generation; 12031 } 12032 get_ctx(child_ctx->parent_ctx); 12033 } 12034 12035 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); 12036 out_unlock: 12037 mutex_unlock(&parent_ctx->mutex); 12038 12039 perf_unpin_context(parent_ctx); 12040 put_ctx(parent_ctx); 12041 12042 return ret; 12043 } 12044 12045 /* 12046 * Initialize the perf_event context in task_struct 12047 */ 12048 int perf_event_init_task(struct task_struct *child) 12049 { 12050 int ctxn, ret; 12051 12052 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp)); 12053 mutex_init(&child->perf_event_mutex); 12054 INIT_LIST_HEAD(&child->perf_event_list); 12055 12056 for_each_task_context_nr(ctxn) { 12057 ret = perf_event_init_context(child, ctxn); 12058 if (ret) { 12059 perf_event_free_task(child); 12060 return ret; 12061 } 12062 } 12063 12064 return 0; 12065 } 12066 12067 static void __init perf_event_init_all_cpus(void) 12068 { 12069 struct swevent_htable *swhash; 12070 int cpu; 12071 12072 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL); 12073 12074 for_each_possible_cpu(cpu) { 12075 swhash = &per_cpu(swevent_htable, cpu); 12076 mutex_init(&swhash->hlist_mutex); 12077 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu)); 12078 12079 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu)); 12080 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu)); 12081 12082 #ifdef CONFIG_CGROUP_PERF 12083 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu)); 12084 #endif 12085 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu)); 12086 } 12087 } 12088 12089 static void perf_swevent_init_cpu(unsigned int cpu) 12090 { 12091 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 12092 12093 mutex_lock(&swhash->hlist_mutex); 12094 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) { 12095 struct swevent_hlist *hlist; 12096 12097 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu)); 12098 WARN_ON(!hlist); 12099 rcu_assign_pointer(swhash->swevent_hlist, hlist); 12100 } 12101 mutex_unlock(&swhash->hlist_mutex); 12102 } 12103 12104 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE 12105 static void __perf_event_exit_context(void *__info) 12106 { 12107 struct perf_event_context *ctx = __info; 12108 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 12109 struct perf_event *event; 12110 12111 raw_spin_lock(&ctx->lock); 12112 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 12113 list_for_each_entry(event, &ctx->event_list, event_entry) 12114 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP); 12115 raw_spin_unlock(&ctx->lock); 12116 } 12117 12118 static void perf_event_exit_cpu_context(int cpu) 12119 { 12120 struct perf_cpu_context *cpuctx; 12121 struct perf_event_context *ctx; 12122 struct pmu *pmu; 12123 12124 mutex_lock(&pmus_lock); 12125 list_for_each_entry(pmu, &pmus, entry) { 12126 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 12127 ctx = &cpuctx->ctx; 12128 12129 mutex_lock(&ctx->mutex); 12130 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1); 12131 cpuctx->online = 0; 12132 mutex_unlock(&ctx->mutex); 12133 } 12134 cpumask_clear_cpu(cpu, perf_online_mask); 12135 mutex_unlock(&pmus_lock); 12136 } 12137 #else 12138 12139 static void perf_event_exit_cpu_context(int cpu) { } 12140 12141 #endif 12142 12143 int perf_event_init_cpu(unsigned int cpu) 12144 { 12145 struct perf_cpu_context *cpuctx; 12146 struct perf_event_context *ctx; 12147 struct pmu *pmu; 12148 12149 perf_swevent_init_cpu(cpu); 12150 12151 mutex_lock(&pmus_lock); 12152 cpumask_set_cpu(cpu, perf_online_mask); 12153 list_for_each_entry(pmu, &pmus, entry) { 12154 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 12155 ctx = &cpuctx->ctx; 12156 12157 mutex_lock(&ctx->mutex); 12158 cpuctx->online = 1; 12159 mutex_unlock(&ctx->mutex); 12160 } 12161 mutex_unlock(&pmus_lock); 12162 12163 return 0; 12164 } 12165 12166 int perf_event_exit_cpu(unsigned int cpu) 12167 { 12168 perf_event_exit_cpu_context(cpu); 12169 return 0; 12170 } 12171 12172 static int 12173 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v) 12174 { 12175 int cpu; 12176 12177 for_each_online_cpu(cpu) 12178 perf_event_exit_cpu(cpu); 12179 12180 return NOTIFY_OK; 12181 } 12182 12183 /* 12184 * Run the perf reboot notifier at the very last possible moment so that 12185 * the generic watchdog code runs as long as possible. 12186 */ 12187 static struct notifier_block perf_reboot_notifier = { 12188 .notifier_call = perf_reboot, 12189 .priority = INT_MIN, 12190 }; 12191 12192 void __init perf_event_init(void) 12193 { 12194 int ret; 12195 12196 idr_init(&pmu_idr); 12197 12198 perf_event_init_all_cpus(); 12199 init_srcu_struct(&pmus_srcu); 12200 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE); 12201 perf_pmu_register(&perf_cpu_clock, NULL, -1); 12202 perf_pmu_register(&perf_task_clock, NULL, -1); 12203 perf_tp_register(); 12204 perf_event_init_cpu(smp_processor_id()); 12205 register_reboot_notifier(&perf_reboot_notifier); 12206 12207 ret = init_hw_breakpoint(); 12208 WARN(ret, "hw_breakpoint initialization failed with: %d", ret); 12209 12210 /* 12211 * Build time assertion that we keep the data_head at the intended 12212 * location. IOW, validation we got the __reserved[] size right. 12213 */ 12214 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head)) 12215 != 1024); 12216 } 12217 12218 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr, 12219 char *page) 12220 { 12221 struct perf_pmu_events_attr *pmu_attr = 12222 container_of(attr, struct perf_pmu_events_attr, attr); 12223 12224 if (pmu_attr->event_str) 12225 return sprintf(page, "%s\n", pmu_attr->event_str); 12226 12227 return 0; 12228 } 12229 EXPORT_SYMBOL_GPL(perf_event_sysfs_show); 12230 12231 static int __init perf_event_sysfs_init(void) 12232 { 12233 struct pmu *pmu; 12234 int ret; 12235 12236 mutex_lock(&pmus_lock); 12237 12238 ret = bus_register(&pmu_bus); 12239 if (ret) 12240 goto unlock; 12241 12242 list_for_each_entry(pmu, &pmus, entry) { 12243 if (!pmu->name || pmu->type < 0) 12244 continue; 12245 12246 ret = pmu_dev_alloc(pmu); 12247 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret); 12248 } 12249 pmu_bus_running = 1; 12250 ret = 0; 12251 12252 unlock: 12253 mutex_unlock(&pmus_lock); 12254 12255 return ret; 12256 } 12257 device_initcall(perf_event_sysfs_init); 12258 12259 #ifdef CONFIG_CGROUP_PERF 12260 static struct cgroup_subsys_state * 12261 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) 12262 { 12263 struct perf_cgroup *jc; 12264 12265 jc = kzalloc(sizeof(*jc), GFP_KERNEL); 12266 if (!jc) 12267 return ERR_PTR(-ENOMEM); 12268 12269 jc->info = alloc_percpu(struct perf_cgroup_info); 12270 if (!jc->info) { 12271 kfree(jc); 12272 return ERR_PTR(-ENOMEM); 12273 } 12274 12275 return &jc->css; 12276 } 12277 12278 static void perf_cgroup_css_free(struct cgroup_subsys_state *css) 12279 { 12280 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css); 12281 12282 free_percpu(jc->info); 12283 kfree(jc); 12284 } 12285 12286 static int __perf_cgroup_move(void *info) 12287 { 12288 struct task_struct *task = info; 12289 rcu_read_lock(); 12290 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN); 12291 rcu_read_unlock(); 12292 return 0; 12293 } 12294 12295 static void perf_cgroup_attach(struct cgroup_taskset *tset) 12296 { 12297 struct task_struct *task; 12298 struct cgroup_subsys_state *css; 12299 12300 cgroup_taskset_for_each(task, css, tset) 12301 task_function_call(task, __perf_cgroup_move, task); 12302 } 12303 12304 struct cgroup_subsys perf_event_cgrp_subsys = { 12305 .css_alloc = perf_cgroup_css_alloc, 12306 .css_free = perf_cgroup_css_free, 12307 .attach = perf_cgroup_attach, 12308 /* 12309 * Implicitly enable on dfl hierarchy so that perf events can 12310 * always be filtered by cgroup2 path as long as perf_event 12311 * controller is not mounted on a legacy hierarchy. 12312 */ 12313 .implicit_on_dfl = true, 12314 .threaded = true, 12315 }; 12316 #endif /* CONFIG_CGROUP_PERF */ 12317