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/hugetlb.h> 32 #include <linux/rculist.h> 33 #include <linux/uaccess.h> 34 #include <linux/syscalls.h> 35 #include <linux/anon_inodes.h> 36 #include <linux/kernel_stat.h> 37 #include <linux/cgroup.h> 38 #include <linux/perf_event.h> 39 #include <linux/trace_events.h> 40 #include <linux/hw_breakpoint.h> 41 #include <linux/mm_types.h> 42 #include <linux/module.h> 43 #include <linux/mman.h> 44 #include <linux/compat.h> 45 #include <linux/bpf.h> 46 #include <linux/filter.h> 47 #include <linux/namei.h> 48 #include <linux/parser.h> 49 #include <linux/sched/clock.h> 50 #include <linux/sched/mm.h> 51 #include <linux/proc_ns.h> 52 #include <linux/mount.h> 53 #include <linux/min_heap.h> 54 #include <linux/highmem.h> 55 #include <linux/pgtable.h> 56 #include <linux/buildid.h> 57 #include <linux/task_work.h> 58 59 #include "internal.h" 60 61 #include <asm/irq_regs.h> 62 63 typedef int (*remote_function_f)(void *); 64 65 struct remote_function_call { 66 struct task_struct *p; 67 remote_function_f func; 68 void *info; 69 int ret; 70 }; 71 72 static void remote_function(void *data) 73 { 74 struct remote_function_call *tfc = data; 75 struct task_struct *p = tfc->p; 76 77 if (p) { 78 /* -EAGAIN */ 79 if (task_cpu(p) != smp_processor_id()) 80 return; 81 82 /* 83 * Now that we're on right CPU with IRQs disabled, we can test 84 * if we hit the right task without races. 85 */ 86 87 tfc->ret = -ESRCH; /* No such (running) process */ 88 if (p != current) 89 return; 90 } 91 92 tfc->ret = tfc->func(tfc->info); 93 } 94 95 /** 96 * task_function_call - call a function on the cpu on which a task runs 97 * @p: the task to evaluate 98 * @func: the function to be called 99 * @info: the function call argument 100 * 101 * Calls the function @func when the task is currently running. This might 102 * be on the current CPU, which just calls the function directly. This will 103 * retry due to any failures in smp_call_function_single(), such as if the 104 * task_cpu() goes offline concurrently. 105 * 106 * returns @func return value or -ESRCH or -ENXIO when the process isn't running 107 */ 108 static int 109 task_function_call(struct task_struct *p, remote_function_f func, void *info) 110 { 111 struct remote_function_call data = { 112 .p = p, 113 .func = func, 114 .info = info, 115 .ret = -EAGAIN, 116 }; 117 int ret; 118 119 for (;;) { 120 ret = smp_call_function_single(task_cpu(p), remote_function, 121 &data, 1); 122 if (!ret) 123 ret = data.ret; 124 125 if (ret != -EAGAIN) 126 break; 127 128 cond_resched(); 129 } 130 131 return ret; 132 } 133 134 /** 135 * cpu_function_call - call a function on the cpu 136 * @cpu: target cpu to queue this function 137 * @func: the function to be called 138 * @info: the function call argument 139 * 140 * Calls the function @func on the remote cpu. 141 * 142 * returns: @func return value or -ENXIO when the cpu is offline 143 */ 144 static int cpu_function_call(int cpu, remote_function_f func, void *info) 145 { 146 struct remote_function_call data = { 147 .p = NULL, 148 .func = func, 149 .info = info, 150 .ret = -ENXIO, /* No such CPU */ 151 }; 152 153 smp_call_function_single(cpu, remote_function, &data, 1); 154 155 return data.ret; 156 } 157 158 static inline struct perf_cpu_context * 159 __get_cpu_context(struct perf_event_context *ctx) 160 { 161 return this_cpu_ptr(ctx->pmu->pmu_cpu_context); 162 } 163 164 static void perf_ctx_lock(struct perf_cpu_context *cpuctx, 165 struct perf_event_context *ctx) 166 { 167 raw_spin_lock(&cpuctx->ctx.lock); 168 if (ctx) 169 raw_spin_lock(&ctx->lock); 170 } 171 172 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx, 173 struct perf_event_context *ctx) 174 { 175 if (ctx) 176 raw_spin_unlock(&ctx->lock); 177 raw_spin_unlock(&cpuctx->ctx.lock); 178 } 179 180 #define TASK_TOMBSTONE ((void *)-1L) 181 182 static bool is_kernel_event(struct perf_event *event) 183 { 184 return READ_ONCE(event->owner) == TASK_TOMBSTONE; 185 } 186 187 /* 188 * On task ctx scheduling... 189 * 190 * When !ctx->nr_events a task context will not be scheduled. This means 191 * we can disable the scheduler hooks (for performance) without leaving 192 * pending task ctx state. 193 * 194 * This however results in two special cases: 195 * 196 * - removing the last event from a task ctx; this is relatively straight 197 * forward and is done in __perf_remove_from_context. 198 * 199 * - adding the first event to a task ctx; this is tricky because we cannot 200 * rely on ctx->is_active and therefore cannot use event_function_call(). 201 * See perf_install_in_context(). 202 * 203 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set. 204 */ 205 206 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *, 207 struct perf_event_context *, void *); 208 209 struct event_function_struct { 210 struct perf_event *event; 211 event_f func; 212 void *data; 213 }; 214 215 static int event_function(void *info) 216 { 217 struct event_function_struct *efs = info; 218 struct perf_event *event = efs->event; 219 struct perf_event_context *ctx = event->ctx; 220 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 221 struct perf_event_context *task_ctx = cpuctx->task_ctx; 222 int ret = 0; 223 224 lockdep_assert_irqs_disabled(); 225 226 perf_ctx_lock(cpuctx, task_ctx); 227 /* 228 * Since we do the IPI call without holding ctx->lock things can have 229 * changed, double check we hit the task we set out to hit. 230 */ 231 if (ctx->task) { 232 if (ctx->task != current) { 233 ret = -ESRCH; 234 goto unlock; 235 } 236 237 /* 238 * We only use event_function_call() on established contexts, 239 * and event_function() is only ever called when active (or 240 * rather, we'll have bailed in task_function_call() or the 241 * above ctx->task != current test), therefore we must have 242 * ctx->is_active here. 243 */ 244 WARN_ON_ONCE(!ctx->is_active); 245 /* 246 * And since we have ctx->is_active, cpuctx->task_ctx must 247 * match. 248 */ 249 WARN_ON_ONCE(task_ctx != ctx); 250 } else { 251 WARN_ON_ONCE(&cpuctx->ctx != ctx); 252 } 253 254 efs->func(event, cpuctx, ctx, efs->data); 255 unlock: 256 perf_ctx_unlock(cpuctx, task_ctx); 257 258 return ret; 259 } 260 261 static void event_function_call(struct perf_event *event, event_f func, void *data) 262 { 263 struct perf_event_context *ctx = event->ctx; 264 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */ 265 struct event_function_struct efs = { 266 .event = event, 267 .func = func, 268 .data = data, 269 }; 270 271 if (!event->parent) { 272 /* 273 * If this is a !child event, we must hold ctx::mutex to 274 * stabilize the event->ctx relation. See 275 * perf_event_ctx_lock(). 276 */ 277 lockdep_assert_held(&ctx->mutex); 278 } 279 280 if (!task) { 281 cpu_function_call(event->cpu, event_function, &efs); 282 return; 283 } 284 285 if (task == TASK_TOMBSTONE) 286 return; 287 288 again: 289 if (!task_function_call(task, event_function, &efs)) 290 return; 291 292 raw_spin_lock_irq(&ctx->lock); 293 /* 294 * Reload the task pointer, it might have been changed by 295 * a concurrent perf_event_context_sched_out(). 296 */ 297 task = ctx->task; 298 if (task == TASK_TOMBSTONE) { 299 raw_spin_unlock_irq(&ctx->lock); 300 return; 301 } 302 if (ctx->is_active) { 303 raw_spin_unlock_irq(&ctx->lock); 304 goto again; 305 } 306 func(event, NULL, ctx, data); 307 raw_spin_unlock_irq(&ctx->lock); 308 } 309 310 /* 311 * Similar to event_function_call() + event_function(), but hard assumes IRQs 312 * are already disabled and we're on the right CPU. 313 */ 314 static void event_function_local(struct perf_event *event, event_f func, void *data) 315 { 316 struct perf_event_context *ctx = event->ctx; 317 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 318 struct task_struct *task = READ_ONCE(ctx->task); 319 struct perf_event_context *task_ctx = NULL; 320 321 lockdep_assert_irqs_disabled(); 322 323 if (task) { 324 if (task == TASK_TOMBSTONE) 325 return; 326 327 task_ctx = ctx; 328 } 329 330 perf_ctx_lock(cpuctx, task_ctx); 331 332 task = ctx->task; 333 if (task == TASK_TOMBSTONE) 334 goto unlock; 335 336 if (task) { 337 /* 338 * We must be either inactive or active and the right task, 339 * otherwise we're screwed, since we cannot IPI to somewhere 340 * else. 341 */ 342 if (ctx->is_active) { 343 if (WARN_ON_ONCE(task != current)) 344 goto unlock; 345 346 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx)) 347 goto unlock; 348 } 349 } else { 350 WARN_ON_ONCE(&cpuctx->ctx != ctx); 351 } 352 353 func(event, cpuctx, ctx, data); 354 unlock: 355 perf_ctx_unlock(cpuctx, task_ctx); 356 } 357 358 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\ 359 PERF_FLAG_FD_OUTPUT |\ 360 PERF_FLAG_PID_CGROUP |\ 361 PERF_FLAG_FD_CLOEXEC) 362 363 /* 364 * branch priv levels that need permission checks 365 */ 366 #define PERF_SAMPLE_BRANCH_PERM_PLM \ 367 (PERF_SAMPLE_BRANCH_KERNEL |\ 368 PERF_SAMPLE_BRANCH_HV) 369 370 enum event_type_t { 371 EVENT_FLEXIBLE = 0x1, 372 EVENT_PINNED = 0x2, 373 EVENT_TIME = 0x4, 374 /* see ctx_resched() for details */ 375 EVENT_CPU = 0x8, 376 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED, 377 }; 378 379 /* 380 * perf_sched_events : >0 events exist 381 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu 382 */ 383 384 static void perf_sched_delayed(struct work_struct *work); 385 DEFINE_STATIC_KEY_FALSE(perf_sched_events); 386 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed); 387 static DEFINE_MUTEX(perf_sched_mutex); 388 static atomic_t perf_sched_count; 389 390 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events); 391 static DEFINE_PER_CPU(int, perf_sched_cb_usages); 392 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events); 393 394 static atomic_t nr_mmap_events __read_mostly; 395 static atomic_t nr_comm_events __read_mostly; 396 static atomic_t nr_namespaces_events __read_mostly; 397 static atomic_t nr_task_events __read_mostly; 398 static atomic_t nr_freq_events __read_mostly; 399 static atomic_t nr_switch_events __read_mostly; 400 static atomic_t nr_ksymbol_events __read_mostly; 401 static atomic_t nr_bpf_events __read_mostly; 402 static atomic_t nr_cgroup_events __read_mostly; 403 static atomic_t nr_text_poke_events __read_mostly; 404 static atomic_t nr_build_id_events __read_mostly; 405 406 static LIST_HEAD(pmus); 407 static DEFINE_MUTEX(pmus_lock); 408 static struct srcu_struct pmus_srcu; 409 static cpumask_var_t perf_online_mask; 410 static struct kmem_cache *perf_event_cache; 411 412 /* 413 * perf event paranoia level: 414 * -1 - not paranoid at all 415 * 0 - disallow raw tracepoint access for unpriv 416 * 1 - disallow cpu events for unpriv 417 * 2 - disallow kernel profiling for unpriv 418 */ 419 int sysctl_perf_event_paranoid __read_mostly = 2; 420 421 /* Minimum for 512 kiB + 1 user control page */ 422 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */ 423 424 /* 425 * max perf event sample rate 426 */ 427 #define DEFAULT_MAX_SAMPLE_RATE 100000 428 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE) 429 #define DEFAULT_CPU_TIME_MAX_PERCENT 25 430 431 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE; 432 433 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ); 434 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS; 435 436 static int perf_sample_allowed_ns __read_mostly = 437 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100; 438 439 static void update_perf_cpu_limits(void) 440 { 441 u64 tmp = perf_sample_period_ns; 442 443 tmp *= sysctl_perf_cpu_time_max_percent; 444 tmp = div_u64(tmp, 100); 445 if (!tmp) 446 tmp = 1; 447 448 WRITE_ONCE(perf_sample_allowed_ns, tmp); 449 } 450 451 static bool perf_rotate_context(struct perf_cpu_context *cpuctx); 452 453 int perf_proc_update_handler(struct ctl_table *table, int write, 454 void *buffer, size_t *lenp, loff_t *ppos) 455 { 456 int ret; 457 int perf_cpu = sysctl_perf_cpu_time_max_percent; 458 /* 459 * If throttling is disabled don't allow the write: 460 */ 461 if (write && (perf_cpu == 100 || perf_cpu == 0)) 462 return -EINVAL; 463 464 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); 465 if (ret || !write) 466 return ret; 467 468 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ); 469 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; 470 update_perf_cpu_limits(); 471 472 return 0; 473 } 474 475 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT; 476 477 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write, 478 void *buffer, size_t *lenp, loff_t *ppos) 479 { 480 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); 481 482 if (ret || !write) 483 return ret; 484 485 if (sysctl_perf_cpu_time_max_percent == 100 || 486 sysctl_perf_cpu_time_max_percent == 0) { 487 printk(KERN_WARNING 488 "perf: Dynamic interrupt throttling disabled, can hang your system!\n"); 489 WRITE_ONCE(perf_sample_allowed_ns, 0); 490 } else { 491 update_perf_cpu_limits(); 492 } 493 494 return 0; 495 } 496 497 /* 498 * perf samples are done in some very critical code paths (NMIs). 499 * If they take too much CPU time, the system can lock up and not 500 * get any real work done. This will drop the sample rate when 501 * we detect that events are taking too long. 502 */ 503 #define NR_ACCUMULATED_SAMPLES 128 504 static DEFINE_PER_CPU(u64, running_sample_length); 505 506 static u64 __report_avg; 507 static u64 __report_allowed; 508 509 static void perf_duration_warn(struct irq_work *w) 510 { 511 printk_ratelimited(KERN_INFO 512 "perf: interrupt took too long (%lld > %lld), lowering " 513 "kernel.perf_event_max_sample_rate to %d\n", 514 __report_avg, __report_allowed, 515 sysctl_perf_event_sample_rate); 516 } 517 518 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn); 519 520 void perf_sample_event_took(u64 sample_len_ns) 521 { 522 u64 max_len = READ_ONCE(perf_sample_allowed_ns); 523 u64 running_len; 524 u64 avg_len; 525 u32 max; 526 527 if (max_len == 0) 528 return; 529 530 /* Decay the counter by 1 average sample. */ 531 running_len = __this_cpu_read(running_sample_length); 532 running_len -= running_len/NR_ACCUMULATED_SAMPLES; 533 running_len += sample_len_ns; 534 __this_cpu_write(running_sample_length, running_len); 535 536 /* 537 * Note: this will be biased artifically low until we have 538 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us 539 * from having to maintain a count. 540 */ 541 avg_len = running_len/NR_ACCUMULATED_SAMPLES; 542 if (avg_len <= max_len) 543 return; 544 545 __report_avg = avg_len; 546 __report_allowed = max_len; 547 548 /* 549 * Compute a throttle threshold 25% below the current duration. 550 */ 551 avg_len += avg_len / 4; 552 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent; 553 if (avg_len < max) 554 max /= (u32)avg_len; 555 else 556 max = 1; 557 558 WRITE_ONCE(perf_sample_allowed_ns, avg_len); 559 WRITE_ONCE(max_samples_per_tick, max); 560 561 sysctl_perf_event_sample_rate = max * HZ; 562 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate; 563 564 if (!irq_work_queue(&perf_duration_work)) { 565 early_printk("perf: interrupt took too long (%lld > %lld), lowering " 566 "kernel.perf_event_max_sample_rate to %d\n", 567 __report_avg, __report_allowed, 568 sysctl_perf_event_sample_rate); 569 } 570 } 571 572 static atomic64_t perf_event_id; 573 574 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, 575 enum event_type_t event_type); 576 577 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, 578 enum event_type_t event_type); 579 580 static void update_context_time(struct perf_event_context *ctx); 581 static u64 perf_event_time(struct perf_event *event); 582 583 void __weak perf_event_print_debug(void) { } 584 585 static inline u64 perf_clock(void) 586 { 587 return local_clock(); 588 } 589 590 static inline u64 perf_event_clock(struct perf_event *event) 591 { 592 return event->clock(); 593 } 594 595 /* 596 * State based event timekeeping... 597 * 598 * The basic idea is to use event->state to determine which (if any) time 599 * fields to increment with the current delta. This means we only need to 600 * update timestamps when we change state or when they are explicitly requested 601 * (read). 602 * 603 * Event groups make things a little more complicated, but not terribly so. The 604 * rules for a group are that if the group leader is OFF the entire group is 605 * OFF, irrespecive of what the group member states are. This results in 606 * __perf_effective_state(). 607 * 608 * A futher ramification is that when a group leader flips between OFF and 609 * !OFF, we need to update all group member times. 610 * 611 * 612 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we 613 * need to make sure the relevant context time is updated before we try and 614 * update our timestamps. 615 */ 616 617 static __always_inline enum perf_event_state 618 __perf_effective_state(struct perf_event *event) 619 { 620 struct perf_event *leader = event->group_leader; 621 622 if (leader->state <= PERF_EVENT_STATE_OFF) 623 return leader->state; 624 625 return event->state; 626 } 627 628 static __always_inline void 629 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running) 630 { 631 enum perf_event_state state = __perf_effective_state(event); 632 u64 delta = now - event->tstamp; 633 634 *enabled = event->total_time_enabled; 635 if (state >= PERF_EVENT_STATE_INACTIVE) 636 *enabled += delta; 637 638 *running = event->total_time_running; 639 if (state >= PERF_EVENT_STATE_ACTIVE) 640 *running += delta; 641 } 642 643 static void perf_event_update_time(struct perf_event *event) 644 { 645 u64 now = perf_event_time(event); 646 647 __perf_update_times(event, now, &event->total_time_enabled, 648 &event->total_time_running); 649 event->tstamp = now; 650 } 651 652 static void perf_event_update_sibling_time(struct perf_event *leader) 653 { 654 struct perf_event *sibling; 655 656 for_each_sibling_event(sibling, leader) 657 perf_event_update_time(sibling); 658 } 659 660 static void 661 perf_event_set_state(struct perf_event *event, enum perf_event_state state) 662 { 663 if (event->state == state) 664 return; 665 666 perf_event_update_time(event); 667 /* 668 * If a group leader gets enabled/disabled all its siblings 669 * are affected too. 670 */ 671 if ((event->state < 0) ^ (state < 0)) 672 perf_event_update_sibling_time(event); 673 674 WRITE_ONCE(event->state, state); 675 } 676 677 /* 678 * UP store-release, load-acquire 679 */ 680 681 #define __store_release(ptr, val) \ 682 do { \ 683 barrier(); \ 684 WRITE_ONCE(*(ptr), (val)); \ 685 } while (0) 686 687 #define __load_acquire(ptr) \ 688 ({ \ 689 __unqual_scalar_typeof(*(ptr)) ___p = READ_ONCE(*(ptr)); \ 690 barrier(); \ 691 ___p; \ 692 }) 693 694 #ifdef CONFIG_CGROUP_PERF 695 696 static inline bool 697 perf_cgroup_match(struct perf_event *event) 698 { 699 struct perf_event_context *ctx = event->ctx; 700 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 701 702 /* @event doesn't care about cgroup */ 703 if (!event->cgrp) 704 return true; 705 706 /* wants specific cgroup scope but @cpuctx isn't associated with any */ 707 if (!cpuctx->cgrp) 708 return false; 709 710 /* 711 * Cgroup scoping is recursive. An event enabled for a cgroup is 712 * also enabled for all its descendant cgroups. If @cpuctx's 713 * cgroup is a descendant of @event's (the test covers identity 714 * case), it's a match. 715 */ 716 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup, 717 event->cgrp->css.cgroup); 718 } 719 720 static inline void perf_detach_cgroup(struct perf_event *event) 721 { 722 css_put(&event->cgrp->css); 723 event->cgrp = NULL; 724 } 725 726 static inline int is_cgroup_event(struct perf_event *event) 727 { 728 return event->cgrp != NULL; 729 } 730 731 static inline u64 perf_cgroup_event_time(struct perf_event *event) 732 { 733 struct perf_cgroup_info *t; 734 735 t = per_cpu_ptr(event->cgrp->info, event->cpu); 736 return t->time; 737 } 738 739 static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now) 740 { 741 struct perf_cgroup_info *t; 742 743 t = per_cpu_ptr(event->cgrp->info, event->cpu); 744 if (!__load_acquire(&t->active)) 745 return t->time; 746 now += READ_ONCE(t->timeoffset); 747 return now; 748 } 749 750 static inline void __update_cgrp_time(struct perf_cgroup_info *info, u64 now, bool adv) 751 { 752 if (adv) 753 info->time += now - info->timestamp; 754 info->timestamp = now; 755 /* 756 * see update_context_time() 757 */ 758 WRITE_ONCE(info->timeoffset, info->time - info->timestamp); 759 } 760 761 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx, bool final) 762 { 763 struct perf_cgroup *cgrp = cpuctx->cgrp; 764 struct cgroup_subsys_state *css; 765 struct perf_cgroup_info *info; 766 767 if (cgrp) { 768 u64 now = perf_clock(); 769 770 for (css = &cgrp->css; css; css = css->parent) { 771 cgrp = container_of(css, struct perf_cgroup, css); 772 info = this_cpu_ptr(cgrp->info); 773 774 __update_cgrp_time(info, now, true); 775 if (final) 776 __store_release(&info->active, 0); 777 } 778 } 779 } 780 781 static inline void update_cgrp_time_from_event(struct perf_event *event) 782 { 783 struct perf_cgroup_info *info; 784 785 /* 786 * ensure we access cgroup data only when needed and 787 * when we know the cgroup is pinned (css_get) 788 */ 789 if (!is_cgroup_event(event)) 790 return; 791 792 info = this_cpu_ptr(event->cgrp->info); 793 /* 794 * Do not update time when cgroup is not active 795 */ 796 if (info->active) 797 __update_cgrp_time(info, perf_clock(), true); 798 } 799 800 static inline void 801 perf_cgroup_set_timestamp(struct perf_cpu_context *cpuctx) 802 { 803 struct perf_event_context *ctx = &cpuctx->ctx; 804 struct perf_cgroup *cgrp = cpuctx->cgrp; 805 struct perf_cgroup_info *info; 806 struct cgroup_subsys_state *css; 807 808 /* 809 * ctx->lock held by caller 810 * ensure we do not access cgroup data 811 * unless we have the cgroup pinned (css_get) 812 */ 813 if (!cgrp) 814 return; 815 816 WARN_ON_ONCE(!ctx->nr_cgroups); 817 818 for (css = &cgrp->css; css; css = css->parent) { 819 cgrp = container_of(css, struct perf_cgroup, css); 820 info = this_cpu_ptr(cgrp->info); 821 __update_cgrp_time(info, ctx->timestamp, false); 822 __store_release(&info->active, 1); 823 } 824 } 825 826 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list); 827 828 /* 829 * reschedule events based on the cgroup constraint of task. 830 */ 831 static void perf_cgroup_switch(struct task_struct *task) 832 { 833 struct perf_cgroup *cgrp; 834 struct perf_cpu_context *cpuctx, *tmp; 835 struct list_head *list; 836 unsigned long flags; 837 838 /* 839 * Disable interrupts and preemption to avoid this CPU's 840 * cgrp_cpuctx_entry to change under us. 841 */ 842 local_irq_save(flags); 843 844 cgrp = perf_cgroup_from_task(task, NULL); 845 846 list = this_cpu_ptr(&cgrp_cpuctx_list); 847 list_for_each_entry_safe(cpuctx, tmp, list, cgrp_cpuctx_entry) { 848 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0); 849 if (READ_ONCE(cpuctx->cgrp) == cgrp) 850 continue; 851 852 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 853 perf_pmu_disable(cpuctx->ctx.pmu); 854 855 cpu_ctx_sched_out(cpuctx, EVENT_ALL); 856 /* 857 * must not be done before ctxswout due 858 * to update_cgrp_time_from_cpuctx() in 859 * ctx_sched_out() 860 */ 861 cpuctx->cgrp = cgrp; 862 /* 863 * set cgrp before ctxsw in to allow 864 * perf_cgroup_set_timestamp() in ctx_sched_in() 865 * to not have to pass task around 866 */ 867 cpu_ctx_sched_in(cpuctx, EVENT_ALL); 868 869 perf_pmu_enable(cpuctx->ctx.pmu); 870 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 871 } 872 873 local_irq_restore(flags); 874 } 875 876 static int perf_cgroup_ensure_storage(struct perf_event *event, 877 struct cgroup_subsys_state *css) 878 { 879 struct perf_cpu_context *cpuctx; 880 struct perf_event **storage; 881 int cpu, heap_size, ret = 0; 882 883 /* 884 * Allow storage to have sufficent space for an iterator for each 885 * possibly nested cgroup plus an iterator for events with no cgroup. 886 */ 887 for (heap_size = 1; css; css = css->parent) 888 heap_size++; 889 890 for_each_possible_cpu(cpu) { 891 cpuctx = per_cpu_ptr(event->pmu->pmu_cpu_context, cpu); 892 if (heap_size <= cpuctx->heap_size) 893 continue; 894 895 storage = kmalloc_node(heap_size * sizeof(struct perf_event *), 896 GFP_KERNEL, cpu_to_node(cpu)); 897 if (!storage) { 898 ret = -ENOMEM; 899 break; 900 } 901 902 raw_spin_lock_irq(&cpuctx->ctx.lock); 903 if (cpuctx->heap_size < heap_size) { 904 swap(cpuctx->heap, storage); 905 if (storage == cpuctx->heap_default) 906 storage = NULL; 907 cpuctx->heap_size = heap_size; 908 } 909 raw_spin_unlock_irq(&cpuctx->ctx.lock); 910 911 kfree(storage); 912 } 913 914 return ret; 915 } 916 917 static inline int perf_cgroup_connect(int fd, struct perf_event *event, 918 struct perf_event_attr *attr, 919 struct perf_event *group_leader) 920 { 921 struct perf_cgroup *cgrp; 922 struct cgroup_subsys_state *css; 923 struct fd f = fdget(fd); 924 int ret = 0; 925 926 if (!f.file) 927 return -EBADF; 928 929 css = css_tryget_online_from_dir(f.file->f_path.dentry, 930 &perf_event_cgrp_subsys); 931 if (IS_ERR(css)) { 932 ret = PTR_ERR(css); 933 goto out; 934 } 935 936 ret = perf_cgroup_ensure_storage(event, css); 937 if (ret) 938 goto out; 939 940 cgrp = container_of(css, struct perf_cgroup, css); 941 event->cgrp = cgrp; 942 943 /* 944 * all events in a group must monitor 945 * the same cgroup because a task belongs 946 * to only one perf cgroup at a time 947 */ 948 if (group_leader && group_leader->cgrp != cgrp) { 949 perf_detach_cgroup(event); 950 ret = -EINVAL; 951 } 952 out: 953 fdput(f); 954 return ret; 955 } 956 957 static inline void 958 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx) 959 { 960 struct perf_cpu_context *cpuctx; 961 962 if (!is_cgroup_event(event)) 963 return; 964 965 /* 966 * Because cgroup events are always per-cpu events, 967 * @ctx == &cpuctx->ctx. 968 */ 969 cpuctx = container_of(ctx, struct perf_cpu_context, ctx); 970 971 if (ctx->nr_cgroups++) 972 return; 973 974 cpuctx->cgrp = perf_cgroup_from_task(current, ctx); 975 list_add(&cpuctx->cgrp_cpuctx_entry, 976 per_cpu_ptr(&cgrp_cpuctx_list, event->cpu)); 977 } 978 979 static inline void 980 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx) 981 { 982 struct perf_cpu_context *cpuctx; 983 984 if (!is_cgroup_event(event)) 985 return; 986 987 /* 988 * Because cgroup events are always per-cpu events, 989 * @ctx == &cpuctx->ctx. 990 */ 991 cpuctx = container_of(ctx, struct perf_cpu_context, ctx); 992 993 if (--ctx->nr_cgroups) 994 return; 995 996 cpuctx->cgrp = NULL; 997 list_del(&cpuctx->cgrp_cpuctx_entry); 998 } 999 1000 #else /* !CONFIG_CGROUP_PERF */ 1001 1002 static inline bool 1003 perf_cgroup_match(struct perf_event *event) 1004 { 1005 return true; 1006 } 1007 1008 static inline void perf_detach_cgroup(struct perf_event *event) 1009 {} 1010 1011 static inline int is_cgroup_event(struct perf_event *event) 1012 { 1013 return 0; 1014 } 1015 1016 static inline void update_cgrp_time_from_event(struct perf_event *event) 1017 { 1018 } 1019 1020 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx, 1021 bool final) 1022 { 1023 } 1024 1025 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event, 1026 struct perf_event_attr *attr, 1027 struct perf_event *group_leader) 1028 { 1029 return -EINVAL; 1030 } 1031 1032 static inline void 1033 perf_cgroup_set_timestamp(struct perf_cpu_context *cpuctx) 1034 { 1035 } 1036 1037 static inline u64 perf_cgroup_event_time(struct perf_event *event) 1038 { 1039 return 0; 1040 } 1041 1042 static inline u64 perf_cgroup_event_time_now(struct perf_event *event, u64 now) 1043 { 1044 return 0; 1045 } 1046 1047 static inline void 1048 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx) 1049 { 1050 } 1051 1052 static inline void 1053 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx) 1054 { 1055 } 1056 1057 static void perf_cgroup_switch(struct task_struct *task) 1058 { 1059 } 1060 #endif 1061 1062 /* 1063 * set default to be dependent on timer tick just 1064 * like original code 1065 */ 1066 #define PERF_CPU_HRTIMER (1000 / HZ) 1067 /* 1068 * function must be called with interrupts disabled 1069 */ 1070 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr) 1071 { 1072 struct perf_cpu_context *cpuctx; 1073 bool rotations; 1074 1075 lockdep_assert_irqs_disabled(); 1076 1077 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer); 1078 rotations = perf_rotate_context(cpuctx); 1079 1080 raw_spin_lock(&cpuctx->hrtimer_lock); 1081 if (rotations) 1082 hrtimer_forward_now(hr, cpuctx->hrtimer_interval); 1083 else 1084 cpuctx->hrtimer_active = 0; 1085 raw_spin_unlock(&cpuctx->hrtimer_lock); 1086 1087 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART; 1088 } 1089 1090 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu) 1091 { 1092 struct hrtimer *timer = &cpuctx->hrtimer; 1093 struct pmu *pmu = cpuctx->ctx.pmu; 1094 u64 interval; 1095 1096 /* no multiplexing needed for SW PMU */ 1097 if (pmu->task_ctx_nr == perf_sw_context) 1098 return; 1099 1100 /* 1101 * check default is sane, if not set then force to 1102 * default interval (1/tick) 1103 */ 1104 interval = pmu->hrtimer_interval_ms; 1105 if (interval < 1) 1106 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER; 1107 1108 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval); 1109 1110 raw_spin_lock_init(&cpuctx->hrtimer_lock); 1111 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD); 1112 timer->function = perf_mux_hrtimer_handler; 1113 } 1114 1115 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx) 1116 { 1117 struct hrtimer *timer = &cpuctx->hrtimer; 1118 struct pmu *pmu = cpuctx->ctx.pmu; 1119 unsigned long flags; 1120 1121 /* not for SW PMU */ 1122 if (pmu->task_ctx_nr == perf_sw_context) 1123 return 0; 1124 1125 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags); 1126 if (!cpuctx->hrtimer_active) { 1127 cpuctx->hrtimer_active = 1; 1128 hrtimer_forward_now(timer, cpuctx->hrtimer_interval); 1129 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD); 1130 } 1131 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags); 1132 1133 return 0; 1134 } 1135 1136 void perf_pmu_disable(struct pmu *pmu) 1137 { 1138 int *count = this_cpu_ptr(pmu->pmu_disable_count); 1139 if (!(*count)++) 1140 pmu->pmu_disable(pmu); 1141 } 1142 1143 void perf_pmu_enable(struct pmu *pmu) 1144 { 1145 int *count = this_cpu_ptr(pmu->pmu_disable_count); 1146 if (!--(*count)) 1147 pmu->pmu_enable(pmu); 1148 } 1149 1150 static DEFINE_PER_CPU(struct list_head, active_ctx_list); 1151 1152 /* 1153 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and 1154 * perf_event_task_tick() are fully serialized because they're strictly cpu 1155 * affine and perf_event_ctx{activate,deactivate} are called with IRQs 1156 * disabled, while perf_event_task_tick is called from IRQ context. 1157 */ 1158 static void perf_event_ctx_activate(struct perf_event_context *ctx) 1159 { 1160 struct list_head *head = this_cpu_ptr(&active_ctx_list); 1161 1162 lockdep_assert_irqs_disabled(); 1163 1164 WARN_ON(!list_empty(&ctx->active_ctx_list)); 1165 1166 list_add(&ctx->active_ctx_list, head); 1167 } 1168 1169 static void perf_event_ctx_deactivate(struct perf_event_context *ctx) 1170 { 1171 lockdep_assert_irqs_disabled(); 1172 1173 WARN_ON(list_empty(&ctx->active_ctx_list)); 1174 1175 list_del_init(&ctx->active_ctx_list); 1176 } 1177 1178 static void get_ctx(struct perf_event_context *ctx) 1179 { 1180 refcount_inc(&ctx->refcount); 1181 } 1182 1183 static void *alloc_task_ctx_data(struct pmu *pmu) 1184 { 1185 if (pmu->task_ctx_cache) 1186 return kmem_cache_zalloc(pmu->task_ctx_cache, GFP_KERNEL); 1187 1188 return NULL; 1189 } 1190 1191 static void free_task_ctx_data(struct pmu *pmu, void *task_ctx_data) 1192 { 1193 if (pmu->task_ctx_cache && task_ctx_data) 1194 kmem_cache_free(pmu->task_ctx_cache, task_ctx_data); 1195 } 1196 1197 static void free_ctx(struct rcu_head *head) 1198 { 1199 struct perf_event_context *ctx; 1200 1201 ctx = container_of(head, struct perf_event_context, rcu_head); 1202 free_task_ctx_data(ctx->pmu, ctx->task_ctx_data); 1203 kfree(ctx); 1204 } 1205 1206 static void put_ctx(struct perf_event_context *ctx) 1207 { 1208 if (refcount_dec_and_test(&ctx->refcount)) { 1209 if (ctx->parent_ctx) 1210 put_ctx(ctx->parent_ctx); 1211 if (ctx->task && ctx->task != TASK_TOMBSTONE) 1212 put_task_struct(ctx->task); 1213 call_rcu(&ctx->rcu_head, free_ctx); 1214 } 1215 } 1216 1217 /* 1218 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and 1219 * perf_pmu_migrate_context() we need some magic. 1220 * 1221 * Those places that change perf_event::ctx will hold both 1222 * perf_event_ctx::mutex of the 'old' and 'new' ctx value. 1223 * 1224 * Lock ordering is by mutex address. There are two other sites where 1225 * perf_event_context::mutex nests and those are: 1226 * 1227 * - perf_event_exit_task_context() [ child , 0 ] 1228 * perf_event_exit_event() 1229 * put_event() [ parent, 1 ] 1230 * 1231 * - perf_event_init_context() [ parent, 0 ] 1232 * inherit_task_group() 1233 * inherit_group() 1234 * inherit_event() 1235 * perf_event_alloc() 1236 * perf_init_event() 1237 * perf_try_init_event() [ child , 1 ] 1238 * 1239 * While it appears there is an obvious deadlock here -- the parent and child 1240 * nesting levels are inverted between the two. This is in fact safe because 1241 * life-time rules separate them. That is an exiting task cannot fork, and a 1242 * spawning task cannot (yet) exit. 1243 * 1244 * But remember that these are parent<->child context relations, and 1245 * migration does not affect children, therefore these two orderings should not 1246 * interact. 1247 * 1248 * The change in perf_event::ctx does not affect children (as claimed above) 1249 * because the sys_perf_event_open() case will install a new event and break 1250 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only 1251 * concerned with cpuctx and that doesn't have children. 1252 * 1253 * The places that change perf_event::ctx will issue: 1254 * 1255 * perf_remove_from_context(); 1256 * synchronize_rcu(); 1257 * perf_install_in_context(); 1258 * 1259 * to affect the change. The remove_from_context() + synchronize_rcu() should 1260 * quiesce the event, after which we can install it in the new location. This 1261 * means that only external vectors (perf_fops, prctl) can perturb the event 1262 * while in transit. Therefore all such accessors should also acquire 1263 * perf_event_context::mutex to serialize against this. 1264 * 1265 * However; because event->ctx can change while we're waiting to acquire 1266 * ctx->mutex we must be careful and use the below perf_event_ctx_lock() 1267 * function. 1268 * 1269 * Lock order: 1270 * exec_update_lock 1271 * task_struct::perf_event_mutex 1272 * perf_event_context::mutex 1273 * perf_event::child_mutex; 1274 * perf_event_context::lock 1275 * perf_event::mmap_mutex 1276 * mmap_lock 1277 * perf_addr_filters_head::lock 1278 * 1279 * cpu_hotplug_lock 1280 * pmus_lock 1281 * cpuctx->mutex / perf_event_context::mutex 1282 */ 1283 static struct perf_event_context * 1284 perf_event_ctx_lock_nested(struct perf_event *event, int nesting) 1285 { 1286 struct perf_event_context *ctx; 1287 1288 again: 1289 rcu_read_lock(); 1290 ctx = READ_ONCE(event->ctx); 1291 if (!refcount_inc_not_zero(&ctx->refcount)) { 1292 rcu_read_unlock(); 1293 goto again; 1294 } 1295 rcu_read_unlock(); 1296 1297 mutex_lock_nested(&ctx->mutex, nesting); 1298 if (event->ctx != ctx) { 1299 mutex_unlock(&ctx->mutex); 1300 put_ctx(ctx); 1301 goto again; 1302 } 1303 1304 return ctx; 1305 } 1306 1307 static inline struct perf_event_context * 1308 perf_event_ctx_lock(struct perf_event *event) 1309 { 1310 return perf_event_ctx_lock_nested(event, 0); 1311 } 1312 1313 static void perf_event_ctx_unlock(struct perf_event *event, 1314 struct perf_event_context *ctx) 1315 { 1316 mutex_unlock(&ctx->mutex); 1317 put_ctx(ctx); 1318 } 1319 1320 /* 1321 * This must be done under the ctx->lock, such as to serialize against 1322 * context_equiv(), therefore we cannot call put_ctx() since that might end up 1323 * calling scheduler related locks and ctx->lock nests inside those. 1324 */ 1325 static __must_check struct perf_event_context * 1326 unclone_ctx(struct perf_event_context *ctx) 1327 { 1328 struct perf_event_context *parent_ctx = ctx->parent_ctx; 1329 1330 lockdep_assert_held(&ctx->lock); 1331 1332 if (parent_ctx) 1333 ctx->parent_ctx = NULL; 1334 ctx->generation++; 1335 1336 return parent_ctx; 1337 } 1338 1339 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p, 1340 enum pid_type type) 1341 { 1342 u32 nr; 1343 /* 1344 * only top level events have the pid namespace they were created in 1345 */ 1346 if (event->parent) 1347 event = event->parent; 1348 1349 nr = __task_pid_nr_ns(p, type, event->ns); 1350 /* avoid -1 if it is idle thread or runs in another ns */ 1351 if (!nr && !pid_alive(p)) 1352 nr = -1; 1353 return nr; 1354 } 1355 1356 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) 1357 { 1358 return perf_event_pid_type(event, p, PIDTYPE_TGID); 1359 } 1360 1361 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) 1362 { 1363 return perf_event_pid_type(event, p, PIDTYPE_PID); 1364 } 1365 1366 /* 1367 * If we inherit events we want to return the parent event id 1368 * to userspace. 1369 */ 1370 static u64 primary_event_id(struct perf_event *event) 1371 { 1372 u64 id = event->id; 1373 1374 if (event->parent) 1375 id = event->parent->id; 1376 1377 return id; 1378 } 1379 1380 /* 1381 * Get the perf_event_context for a task and lock it. 1382 * 1383 * This has to cope with the fact that until it is locked, 1384 * the context could get moved to another task. 1385 */ 1386 static struct perf_event_context * 1387 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags) 1388 { 1389 struct perf_event_context *ctx; 1390 1391 retry: 1392 /* 1393 * One of the few rules of preemptible RCU is that one cannot do 1394 * rcu_read_unlock() while holding a scheduler (or nested) lock when 1395 * part of the read side critical section was irqs-enabled -- see 1396 * rcu_read_unlock_special(). 1397 * 1398 * Since ctx->lock nests under rq->lock we must ensure the entire read 1399 * side critical section has interrupts disabled. 1400 */ 1401 local_irq_save(*flags); 1402 rcu_read_lock(); 1403 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]); 1404 if (ctx) { 1405 /* 1406 * If this context is a clone of another, it might 1407 * get swapped for another underneath us by 1408 * perf_event_task_sched_out, though the 1409 * rcu_read_lock() protects us from any context 1410 * getting freed. Lock the context and check if it 1411 * got swapped before we could get the lock, and retry 1412 * if so. If we locked the right context, then it 1413 * can't get swapped on us any more. 1414 */ 1415 raw_spin_lock(&ctx->lock); 1416 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) { 1417 raw_spin_unlock(&ctx->lock); 1418 rcu_read_unlock(); 1419 local_irq_restore(*flags); 1420 goto retry; 1421 } 1422 1423 if (ctx->task == TASK_TOMBSTONE || 1424 !refcount_inc_not_zero(&ctx->refcount)) { 1425 raw_spin_unlock(&ctx->lock); 1426 ctx = NULL; 1427 } else { 1428 WARN_ON_ONCE(ctx->task != task); 1429 } 1430 } 1431 rcu_read_unlock(); 1432 if (!ctx) 1433 local_irq_restore(*flags); 1434 return ctx; 1435 } 1436 1437 /* 1438 * Get the context for a task and increment its pin_count so it 1439 * can't get swapped to another task. This also increments its 1440 * reference count so that the context can't get freed. 1441 */ 1442 static struct perf_event_context * 1443 perf_pin_task_context(struct task_struct *task, int ctxn) 1444 { 1445 struct perf_event_context *ctx; 1446 unsigned long flags; 1447 1448 ctx = perf_lock_task_context(task, ctxn, &flags); 1449 if (ctx) { 1450 ++ctx->pin_count; 1451 raw_spin_unlock_irqrestore(&ctx->lock, flags); 1452 } 1453 return ctx; 1454 } 1455 1456 static void perf_unpin_context(struct perf_event_context *ctx) 1457 { 1458 unsigned long flags; 1459 1460 raw_spin_lock_irqsave(&ctx->lock, flags); 1461 --ctx->pin_count; 1462 raw_spin_unlock_irqrestore(&ctx->lock, flags); 1463 } 1464 1465 /* 1466 * Update the record of the current time in a context. 1467 */ 1468 static void __update_context_time(struct perf_event_context *ctx, bool adv) 1469 { 1470 u64 now = perf_clock(); 1471 1472 lockdep_assert_held(&ctx->lock); 1473 1474 if (adv) 1475 ctx->time += now - ctx->timestamp; 1476 ctx->timestamp = now; 1477 1478 /* 1479 * The above: time' = time + (now - timestamp), can be re-arranged 1480 * into: time` = now + (time - timestamp), which gives a single value 1481 * offset to compute future time without locks on. 1482 * 1483 * See perf_event_time_now(), which can be used from NMI context where 1484 * it's (obviously) not possible to acquire ctx->lock in order to read 1485 * both the above values in a consistent manner. 1486 */ 1487 WRITE_ONCE(ctx->timeoffset, ctx->time - ctx->timestamp); 1488 } 1489 1490 static void update_context_time(struct perf_event_context *ctx) 1491 { 1492 __update_context_time(ctx, true); 1493 } 1494 1495 static u64 perf_event_time(struct perf_event *event) 1496 { 1497 struct perf_event_context *ctx = event->ctx; 1498 1499 if (unlikely(!ctx)) 1500 return 0; 1501 1502 if (is_cgroup_event(event)) 1503 return perf_cgroup_event_time(event); 1504 1505 return ctx->time; 1506 } 1507 1508 static u64 perf_event_time_now(struct perf_event *event, u64 now) 1509 { 1510 struct perf_event_context *ctx = event->ctx; 1511 1512 if (unlikely(!ctx)) 1513 return 0; 1514 1515 if (is_cgroup_event(event)) 1516 return perf_cgroup_event_time_now(event, now); 1517 1518 if (!(__load_acquire(&ctx->is_active) & EVENT_TIME)) 1519 return ctx->time; 1520 1521 now += READ_ONCE(ctx->timeoffset); 1522 return now; 1523 } 1524 1525 static enum event_type_t get_event_type(struct perf_event *event) 1526 { 1527 struct perf_event_context *ctx = event->ctx; 1528 enum event_type_t event_type; 1529 1530 lockdep_assert_held(&ctx->lock); 1531 1532 /* 1533 * It's 'group type', really, because if our group leader is 1534 * pinned, so are we. 1535 */ 1536 if (event->group_leader != event) 1537 event = event->group_leader; 1538 1539 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE; 1540 if (!ctx->task) 1541 event_type |= EVENT_CPU; 1542 1543 return event_type; 1544 } 1545 1546 /* 1547 * Helper function to initialize event group nodes. 1548 */ 1549 static void init_event_group(struct perf_event *event) 1550 { 1551 RB_CLEAR_NODE(&event->group_node); 1552 event->group_index = 0; 1553 } 1554 1555 /* 1556 * Extract pinned or flexible groups from the context 1557 * based on event attrs bits. 1558 */ 1559 static struct perf_event_groups * 1560 get_event_groups(struct perf_event *event, struct perf_event_context *ctx) 1561 { 1562 if (event->attr.pinned) 1563 return &ctx->pinned_groups; 1564 else 1565 return &ctx->flexible_groups; 1566 } 1567 1568 /* 1569 * Helper function to initializes perf_event_group trees. 1570 */ 1571 static void perf_event_groups_init(struct perf_event_groups *groups) 1572 { 1573 groups->tree = RB_ROOT; 1574 groups->index = 0; 1575 } 1576 1577 static inline struct cgroup *event_cgroup(const struct perf_event *event) 1578 { 1579 struct cgroup *cgroup = NULL; 1580 1581 #ifdef CONFIG_CGROUP_PERF 1582 if (event->cgrp) 1583 cgroup = event->cgrp->css.cgroup; 1584 #endif 1585 1586 return cgroup; 1587 } 1588 1589 /* 1590 * Compare function for event groups; 1591 * 1592 * Implements complex key that first sorts by CPU and then by virtual index 1593 * which provides ordering when rotating groups for the same CPU. 1594 */ 1595 static __always_inline int 1596 perf_event_groups_cmp(const int left_cpu, const struct cgroup *left_cgroup, 1597 const u64 left_group_index, const struct perf_event *right) 1598 { 1599 if (left_cpu < right->cpu) 1600 return -1; 1601 if (left_cpu > right->cpu) 1602 return 1; 1603 1604 #ifdef CONFIG_CGROUP_PERF 1605 { 1606 const struct cgroup *right_cgroup = event_cgroup(right); 1607 1608 if (left_cgroup != right_cgroup) { 1609 if (!left_cgroup) { 1610 /* 1611 * Left has no cgroup but right does, no 1612 * cgroups come first. 1613 */ 1614 return -1; 1615 } 1616 if (!right_cgroup) { 1617 /* 1618 * Right has no cgroup but left does, no 1619 * cgroups come first. 1620 */ 1621 return 1; 1622 } 1623 /* Two dissimilar cgroups, order by id. */ 1624 if (cgroup_id(left_cgroup) < cgroup_id(right_cgroup)) 1625 return -1; 1626 1627 return 1; 1628 } 1629 } 1630 #endif 1631 1632 if (left_group_index < right->group_index) 1633 return -1; 1634 if (left_group_index > right->group_index) 1635 return 1; 1636 1637 return 0; 1638 } 1639 1640 #define __node_2_pe(node) \ 1641 rb_entry((node), struct perf_event, group_node) 1642 1643 static inline bool __group_less(struct rb_node *a, const struct rb_node *b) 1644 { 1645 struct perf_event *e = __node_2_pe(a); 1646 return perf_event_groups_cmp(e->cpu, event_cgroup(e), e->group_index, 1647 __node_2_pe(b)) < 0; 1648 } 1649 1650 struct __group_key { 1651 int cpu; 1652 struct cgroup *cgroup; 1653 }; 1654 1655 static inline int __group_cmp(const void *key, const struct rb_node *node) 1656 { 1657 const struct __group_key *a = key; 1658 const struct perf_event *b = __node_2_pe(node); 1659 1660 /* partial/subtree match: @cpu, @cgroup; ignore: @group_index */ 1661 return perf_event_groups_cmp(a->cpu, a->cgroup, b->group_index, b); 1662 } 1663 1664 /* 1665 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for 1666 * key (see perf_event_groups_less). This places it last inside the CPU 1667 * subtree. 1668 */ 1669 static void 1670 perf_event_groups_insert(struct perf_event_groups *groups, 1671 struct perf_event *event) 1672 { 1673 event->group_index = ++groups->index; 1674 1675 rb_add(&event->group_node, &groups->tree, __group_less); 1676 } 1677 1678 /* 1679 * Helper function to insert event into the pinned or flexible groups. 1680 */ 1681 static void 1682 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx) 1683 { 1684 struct perf_event_groups *groups; 1685 1686 groups = get_event_groups(event, ctx); 1687 perf_event_groups_insert(groups, event); 1688 } 1689 1690 /* 1691 * Delete a group from a tree. 1692 */ 1693 static void 1694 perf_event_groups_delete(struct perf_event_groups *groups, 1695 struct perf_event *event) 1696 { 1697 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) || 1698 RB_EMPTY_ROOT(&groups->tree)); 1699 1700 rb_erase(&event->group_node, &groups->tree); 1701 init_event_group(event); 1702 } 1703 1704 /* 1705 * Helper function to delete event from its groups. 1706 */ 1707 static void 1708 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx) 1709 { 1710 struct perf_event_groups *groups; 1711 1712 groups = get_event_groups(event, ctx); 1713 perf_event_groups_delete(groups, event); 1714 } 1715 1716 /* 1717 * Get the leftmost event in the cpu/cgroup subtree. 1718 */ 1719 static struct perf_event * 1720 perf_event_groups_first(struct perf_event_groups *groups, int cpu, 1721 struct cgroup *cgrp) 1722 { 1723 struct __group_key key = { 1724 .cpu = cpu, 1725 .cgroup = cgrp, 1726 }; 1727 struct rb_node *node; 1728 1729 node = rb_find_first(&key, &groups->tree, __group_cmp); 1730 if (node) 1731 return __node_2_pe(node); 1732 1733 return NULL; 1734 } 1735 1736 /* 1737 * Like rb_entry_next_safe() for the @cpu subtree. 1738 */ 1739 static struct perf_event * 1740 perf_event_groups_next(struct perf_event *event) 1741 { 1742 struct __group_key key = { 1743 .cpu = event->cpu, 1744 .cgroup = event_cgroup(event), 1745 }; 1746 struct rb_node *next; 1747 1748 next = rb_next_match(&key, &event->group_node, __group_cmp); 1749 if (next) 1750 return __node_2_pe(next); 1751 1752 return NULL; 1753 } 1754 1755 /* 1756 * Iterate through the whole groups tree. 1757 */ 1758 #define perf_event_groups_for_each(event, groups) \ 1759 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \ 1760 typeof(*event), group_node); event; \ 1761 event = rb_entry_safe(rb_next(&event->group_node), \ 1762 typeof(*event), group_node)) 1763 1764 /* 1765 * Add an event from the lists for its context. 1766 * Must be called with ctx->mutex and ctx->lock held. 1767 */ 1768 static void 1769 list_add_event(struct perf_event *event, struct perf_event_context *ctx) 1770 { 1771 lockdep_assert_held(&ctx->lock); 1772 1773 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT); 1774 event->attach_state |= PERF_ATTACH_CONTEXT; 1775 1776 event->tstamp = perf_event_time(event); 1777 1778 /* 1779 * If we're a stand alone event or group leader, we go to the context 1780 * list, group events are kept attached to the group so that 1781 * perf_group_detach can, at all times, locate all siblings. 1782 */ 1783 if (event->group_leader == event) { 1784 event->group_caps = event->event_caps; 1785 add_event_to_groups(event, ctx); 1786 } 1787 1788 list_add_rcu(&event->event_entry, &ctx->event_list); 1789 ctx->nr_events++; 1790 if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT) 1791 ctx->nr_user++; 1792 if (event->attr.inherit_stat) 1793 ctx->nr_stat++; 1794 1795 if (event->state > PERF_EVENT_STATE_OFF) 1796 perf_cgroup_event_enable(event, ctx); 1797 1798 ctx->generation++; 1799 } 1800 1801 /* 1802 * Initialize event state based on the perf_event_attr::disabled. 1803 */ 1804 static inline void perf_event__state_init(struct perf_event *event) 1805 { 1806 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF : 1807 PERF_EVENT_STATE_INACTIVE; 1808 } 1809 1810 static void __perf_event_read_size(struct perf_event *event, int nr_siblings) 1811 { 1812 int entry = sizeof(u64); /* value */ 1813 int size = 0; 1814 int nr = 1; 1815 1816 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 1817 size += sizeof(u64); 1818 1819 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 1820 size += sizeof(u64); 1821 1822 if (event->attr.read_format & PERF_FORMAT_ID) 1823 entry += sizeof(u64); 1824 1825 if (event->attr.read_format & PERF_FORMAT_LOST) 1826 entry += sizeof(u64); 1827 1828 if (event->attr.read_format & PERF_FORMAT_GROUP) { 1829 nr += nr_siblings; 1830 size += sizeof(u64); 1831 } 1832 1833 size += entry * nr; 1834 event->read_size = size; 1835 } 1836 1837 static void __perf_event_header_size(struct perf_event *event, u64 sample_type) 1838 { 1839 struct perf_sample_data *data; 1840 u16 size = 0; 1841 1842 if (sample_type & PERF_SAMPLE_IP) 1843 size += sizeof(data->ip); 1844 1845 if (sample_type & PERF_SAMPLE_ADDR) 1846 size += sizeof(data->addr); 1847 1848 if (sample_type & PERF_SAMPLE_PERIOD) 1849 size += sizeof(data->period); 1850 1851 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE) 1852 size += sizeof(data->weight.full); 1853 1854 if (sample_type & PERF_SAMPLE_READ) 1855 size += event->read_size; 1856 1857 if (sample_type & PERF_SAMPLE_DATA_SRC) 1858 size += sizeof(data->data_src.val); 1859 1860 if (sample_type & PERF_SAMPLE_TRANSACTION) 1861 size += sizeof(data->txn); 1862 1863 if (sample_type & PERF_SAMPLE_PHYS_ADDR) 1864 size += sizeof(data->phys_addr); 1865 1866 if (sample_type & PERF_SAMPLE_CGROUP) 1867 size += sizeof(data->cgroup); 1868 1869 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE) 1870 size += sizeof(data->data_page_size); 1871 1872 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE) 1873 size += sizeof(data->code_page_size); 1874 1875 event->header_size = size; 1876 } 1877 1878 /* 1879 * Called at perf_event creation and when events are attached/detached from a 1880 * group. 1881 */ 1882 static void perf_event__header_size(struct perf_event *event) 1883 { 1884 __perf_event_read_size(event, 1885 event->group_leader->nr_siblings); 1886 __perf_event_header_size(event, event->attr.sample_type); 1887 } 1888 1889 static void perf_event__id_header_size(struct perf_event *event) 1890 { 1891 struct perf_sample_data *data; 1892 u64 sample_type = event->attr.sample_type; 1893 u16 size = 0; 1894 1895 if (sample_type & PERF_SAMPLE_TID) 1896 size += sizeof(data->tid_entry); 1897 1898 if (sample_type & PERF_SAMPLE_TIME) 1899 size += sizeof(data->time); 1900 1901 if (sample_type & PERF_SAMPLE_IDENTIFIER) 1902 size += sizeof(data->id); 1903 1904 if (sample_type & PERF_SAMPLE_ID) 1905 size += sizeof(data->id); 1906 1907 if (sample_type & PERF_SAMPLE_STREAM_ID) 1908 size += sizeof(data->stream_id); 1909 1910 if (sample_type & PERF_SAMPLE_CPU) 1911 size += sizeof(data->cpu_entry); 1912 1913 event->id_header_size = size; 1914 } 1915 1916 static bool perf_event_validate_size(struct perf_event *event) 1917 { 1918 /* 1919 * The values computed here will be over-written when we actually 1920 * attach the event. 1921 */ 1922 __perf_event_read_size(event, event->group_leader->nr_siblings + 1); 1923 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ); 1924 perf_event__id_header_size(event); 1925 1926 /* 1927 * Sum the lot; should not exceed the 64k limit we have on records. 1928 * Conservative limit to allow for callchains and other variable fields. 1929 */ 1930 if (event->read_size + event->header_size + 1931 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024) 1932 return false; 1933 1934 return true; 1935 } 1936 1937 static void perf_group_attach(struct perf_event *event) 1938 { 1939 struct perf_event *group_leader = event->group_leader, *pos; 1940 1941 lockdep_assert_held(&event->ctx->lock); 1942 1943 /* 1944 * We can have double attach due to group movement in perf_event_open. 1945 */ 1946 if (event->attach_state & PERF_ATTACH_GROUP) 1947 return; 1948 1949 event->attach_state |= PERF_ATTACH_GROUP; 1950 1951 if (group_leader == event) 1952 return; 1953 1954 WARN_ON_ONCE(group_leader->ctx != event->ctx); 1955 1956 group_leader->group_caps &= event->event_caps; 1957 1958 list_add_tail(&event->sibling_list, &group_leader->sibling_list); 1959 group_leader->nr_siblings++; 1960 1961 perf_event__header_size(group_leader); 1962 1963 for_each_sibling_event(pos, group_leader) 1964 perf_event__header_size(pos); 1965 } 1966 1967 /* 1968 * Remove an event from the lists for its context. 1969 * Must be called with ctx->mutex and ctx->lock held. 1970 */ 1971 static void 1972 list_del_event(struct perf_event *event, struct perf_event_context *ctx) 1973 { 1974 WARN_ON_ONCE(event->ctx != ctx); 1975 lockdep_assert_held(&ctx->lock); 1976 1977 /* 1978 * We can have double detach due to exit/hot-unplug + close. 1979 */ 1980 if (!(event->attach_state & PERF_ATTACH_CONTEXT)) 1981 return; 1982 1983 event->attach_state &= ~PERF_ATTACH_CONTEXT; 1984 1985 ctx->nr_events--; 1986 if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT) 1987 ctx->nr_user--; 1988 if (event->attr.inherit_stat) 1989 ctx->nr_stat--; 1990 1991 list_del_rcu(&event->event_entry); 1992 1993 if (event->group_leader == event) 1994 del_event_from_groups(event, ctx); 1995 1996 /* 1997 * If event was in error state, then keep it 1998 * that way, otherwise bogus counts will be 1999 * returned on read(). The only way to get out 2000 * of error state is by explicit re-enabling 2001 * of the event 2002 */ 2003 if (event->state > PERF_EVENT_STATE_OFF) { 2004 perf_cgroup_event_disable(event, ctx); 2005 perf_event_set_state(event, PERF_EVENT_STATE_OFF); 2006 } 2007 2008 ctx->generation++; 2009 } 2010 2011 static int 2012 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event) 2013 { 2014 if (!has_aux(aux_event)) 2015 return 0; 2016 2017 if (!event->pmu->aux_output_match) 2018 return 0; 2019 2020 return event->pmu->aux_output_match(aux_event); 2021 } 2022 2023 static void put_event(struct perf_event *event); 2024 static void event_sched_out(struct perf_event *event, 2025 struct perf_cpu_context *cpuctx, 2026 struct perf_event_context *ctx); 2027 2028 static void perf_put_aux_event(struct perf_event *event) 2029 { 2030 struct perf_event_context *ctx = event->ctx; 2031 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 2032 struct perf_event *iter; 2033 2034 /* 2035 * If event uses aux_event tear down the link 2036 */ 2037 if (event->aux_event) { 2038 iter = event->aux_event; 2039 event->aux_event = NULL; 2040 put_event(iter); 2041 return; 2042 } 2043 2044 /* 2045 * If the event is an aux_event, tear down all links to 2046 * it from other events. 2047 */ 2048 for_each_sibling_event(iter, event->group_leader) { 2049 if (iter->aux_event != event) 2050 continue; 2051 2052 iter->aux_event = NULL; 2053 put_event(event); 2054 2055 /* 2056 * If it's ACTIVE, schedule it out and put it into ERROR 2057 * state so that we don't try to schedule it again. Note 2058 * that perf_event_enable() will clear the ERROR status. 2059 */ 2060 event_sched_out(iter, cpuctx, ctx); 2061 perf_event_set_state(event, PERF_EVENT_STATE_ERROR); 2062 } 2063 } 2064 2065 static bool perf_need_aux_event(struct perf_event *event) 2066 { 2067 return !!event->attr.aux_output || !!event->attr.aux_sample_size; 2068 } 2069 2070 static int perf_get_aux_event(struct perf_event *event, 2071 struct perf_event *group_leader) 2072 { 2073 /* 2074 * Our group leader must be an aux event if we want to be 2075 * an aux_output. This way, the aux event will precede its 2076 * aux_output events in the group, and therefore will always 2077 * schedule first. 2078 */ 2079 if (!group_leader) 2080 return 0; 2081 2082 /* 2083 * aux_output and aux_sample_size are mutually exclusive. 2084 */ 2085 if (event->attr.aux_output && event->attr.aux_sample_size) 2086 return 0; 2087 2088 if (event->attr.aux_output && 2089 !perf_aux_output_match(event, group_leader)) 2090 return 0; 2091 2092 if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux) 2093 return 0; 2094 2095 if (!atomic_long_inc_not_zero(&group_leader->refcount)) 2096 return 0; 2097 2098 /* 2099 * Link aux_outputs to their aux event; this is undone in 2100 * perf_group_detach() by perf_put_aux_event(). When the 2101 * group in torn down, the aux_output events loose their 2102 * link to the aux_event and can't schedule any more. 2103 */ 2104 event->aux_event = group_leader; 2105 2106 return 1; 2107 } 2108 2109 static inline struct list_head *get_event_list(struct perf_event *event) 2110 { 2111 struct perf_event_context *ctx = event->ctx; 2112 return event->attr.pinned ? &ctx->pinned_active : &ctx->flexible_active; 2113 } 2114 2115 /* 2116 * Events that have PERF_EV_CAP_SIBLING require being part of a group and 2117 * cannot exist on their own, schedule them out and move them into the ERROR 2118 * state. Also see _perf_event_enable(), it will not be able to recover 2119 * this ERROR state. 2120 */ 2121 static inline void perf_remove_sibling_event(struct perf_event *event) 2122 { 2123 struct perf_event_context *ctx = event->ctx; 2124 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 2125 2126 event_sched_out(event, cpuctx, ctx); 2127 perf_event_set_state(event, PERF_EVENT_STATE_ERROR); 2128 } 2129 2130 static void perf_group_detach(struct perf_event *event) 2131 { 2132 struct perf_event *leader = event->group_leader; 2133 struct perf_event *sibling, *tmp; 2134 struct perf_event_context *ctx = event->ctx; 2135 2136 lockdep_assert_held(&ctx->lock); 2137 2138 /* 2139 * We can have double detach due to exit/hot-unplug + close. 2140 */ 2141 if (!(event->attach_state & PERF_ATTACH_GROUP)) 2142 return; 2143 2144 event->attach_state &= ~PERF_ATTACH_GROUP; 2145 2146 perf_put_aux_event(event); 2147 2148 /* 2149 * If this is a sibling, remove it from its group. 2150 */ 2151 if (leader != event) { 2152 list_del_init(&event->sibling_list); 2153 event->group_leader->nr_siblings--; 2154 goto out; 2155 } 2156 2157 /* 2158 * If this was a group event with sibling events then 2159 * upgrade the siblings to singleton events by adding them 2160 * to whatever list we are on. 2161 */ 2162 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) { 2163 2164 if (sibling->event_caps & PERF_EV_CAP_SIBLING) 2165 perf_remove_sibling_event(sibling); 2166 2167 sibling->group_leader = sibling; 2168 list_del_init(&sibling->sibling_list); 2169 2170 /* Inherit group flags from the previous leader */ 2171 sibling->group_caps = event->group_caps; 2172 2173 if (!RB_EMPTY_NODE(&event->group_node)) { 2174 add_event_to_groups(sibling, event->ctx); 2175 2176 if (sibling->state == PERF_EVENT_STATE_ACTIVE) 2177 list_add_tail(&sibling->active_list, get_event_list(sibling)); 2178 } 2179 2180 WARN_ON_ONCE(sibling->ctx != event->ctx); 2181 } 2182 2183 out: 2184 for_each_sibling_event(tmp, leader) 2185 perf_event__header_size(tmp); 2186 2187 perf_event__header_size(leader); 2188 } 2189 2190 static void sync_child_event(struct perf_event *child_event); 2191 2192 static void perf_child_detach(struct perf_event *event) 2193 { 2194 struct perf_event *parent_event = event->parent; 2195 2196 if (!(event->attach_state & PERF_ATTACH_CHILD)) 2197 return; 2198 2199 event->attach_state &= ~PERF_ATTACH_CHILD; 2200 2201 if (WARN_ON_ONCE(!parent_event)) 2202 return; 2203 2204 lockdep_assert_held(&parent_event->child_mutex); 2205 2206 sync_child_event(event); 2207 list_del_init(&event->child_list); 2208 } 2209 2210 static bool is_orphaned_event(struct perf_event *event) 2211 { 2212 return event->state == PERF_EVENT_STATE_DEAD; 2213 } 2214 2215 static inline int __pmu_filter_match(struct perf_event *event) 2216 { 2217 struct pmu *pmu = event->pmu; 2218 return pmu->filter_match ? pmu->filter_match(event) : 1; 2219 } 2220 2221 /* 2222 * Check whether we should attempt to schedule an event group based on 2223 * PMU-specific filtering. An event group can consist of HW and SW events, 2224 * potentially with a SW leader, so we must check all the filters, to 2225 * determine whether a group is schedulable: 2226 */ 2227 static inline int pmu_filter_match(struct perf_event *event) 2228 { 2229 struct perf_event *sibling; 2230 unsigned long flags; 2231 int ret = 1; 2232 2233 if (!__pmu_filter_match(event)) 2234 return 0; 2235 2236 local_irq_save(flags); 2237 for_each_sibling_event(sibling, event) { 2238 if (!__pmu_filter_match(sibling)) { 2239 ret = 0; 2240 break; 2241 } 2242 } 2243 local_irq_restore(flags); 2244 2245 return ret; 2246 } 2247 2248 static inline int 2249 event_filter_match(struct perf_event *event) 2250 { 2251 return (event->cpu == -1 || event->cpu == smp_processor_id()) && 2252 perf_cgroup_match(event) && pmu_filter_match(event); 2253 } 2254 2255 static void 2256 event_sched_out(struct perf_event *event, 2257 struct perf_cpu_context *cpuctx, 2258 struct perf_event_context *ctx) 2259 { 2260 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE; 2261 2262 WARN_ON_ONCE(event->ctx != ctx); 2263 lockdep_assert_held(&ctx->lock); 2264 2265 if (event->state != PERF_EVENT_STATE_ACTIVE) 2266 return; 2267 2268 /* 2269 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but 2270 * we can schedule events _OUT_ individually through things like 2271 * __perf_remove_from_context(). 2272 */ 2273 list_del_init(&event->active_list); 2274 2275 perf_pmu_disable(event->pmu); 2276 2277 event->pmu->del(event, 0); 2278 event->oncpu = -1; 2279 2280 if (event->pending_disable) { 2281 event->pending_disable = 0; 2282 perf_cgroup_event_disable(event, ctx); 2283 state = PERF_EVENT_STATE_OFF; 2284 } 2285 2286 if (event->pending_sigtrap) { 2287 bool dec = true; 2288 2289 event->pending_sigtrap = 0; 2290 if (state != PERF_EVENT_STATE_OFF && 2291 !event->pending_work) { 2292 event->pending_work = 1; 2293 dec = false; 2294 task_work_add(current, &event->pending_task, TWA_RESUME); 2295 } 2296 if (dec) 2297 local_dec(&event->ctx->nr_pending); 2298 } 2299 2300 perf_event_set_state(event, state); 2301 2302 if (!is_software_event(event)) 2303 cpuctx->active_oncpu--; 2304 if (!--ctx->nr_active) 2305 perf_event_ctx_deactivate(ctx); 2306 if (event->attr.freq && event->attr.sample_freq) 2307 ctx->nr_freq--; 2308 if (event->attr.exclusive || !cpuctx->active_oncpu) 2309 cpuctx->exclusive = 0; 2310 2311 perf_pmu_enable(event->pmu); 2312 } 2313 2314 static void 2315 group_sched_out(struct perf_event *group_event, 2316 struct perf_cpu_context *cpuctx, 2317 struct perf_event_context *ctx) 2318 { 2319 struct perf_event *event; 2320 2321 if (group_event->state != PERF_EVENT_STATE_ACTIVE) 2322 return; 2323 2324 perf_pmu_disable(ctx->pmu); 2325 2326 event_sched_out(group_event, cpuctx, ctx); 2327 2328 /* 2329 * Schedule out siblings (if any): 2330 */ 2331 for_each_sibling_event(event, group_event) 2332 event_sched_out(event, cpuctx, ctx); 2333 2334 perf_pmu_enable(ctx->pmu); 2335 } 2336 2337 #define DETACH_GROUP 0x01UL 2338 #define DETACH_CHILD 0x02UL 2339 2340 /* 2341 * Cross CPU call to remove a performance event 2342 * 2343 * We disable the event on the hardware level first. After that we 2344 * remove it from the context list. 2345 */ 2346 static void 2347 __perf_remove_from_context(struct perf_event *event, 2348 struct perf_cpu_context *cpuctx, 2349 struct perf_event_context *ctx, 2350 void *info) 2351 { 2352 unsigned long flags = (unsigned long)info; 2353 2354 if (ctx->is_active & EVENT_TIME) { 2355 update_context_time(ctx); 2356 update_cgrp_time_from_cpuctx(cpuctx, false); 2357 } 2358 2359 event_sched_out(event, cpuctx, ctx); 2360 if (flags & DETACH_GROUP) 2361 perf_group_detach(event); 2362 if (flags & DETACH_CHILD) 2363 perf_child_detach(event); 2364 list_del_event(event, ctx); 2365 2366 if (!ctx->nr_events && ctx->is_active) { 2367 if (ctx == &cpuctx->ctx) 2368 update_cgrp_time_from_cpuctx(cpuctx, true); 2369 2370 ctx->is_active = 0; 2371 ctx->rotate_necessary = 0; 2372 if (ctx->task) { 2373 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 2374 cpuctx->task_ctx = NULL; 2375 } 2376 } 2377 } 2378 2379 /* 2380 * Remove the event from a task's (or a CPU's) list of events. 2381 * 2382 * If event->ctx is a cloned context, callers must make sure that 2383 * every task struct that event->ctx->task could possibly point to 2384 * remains valid. This is OK when called from perf_release since 2385 * that only calls us on the top-level context, which can't be a clone. 2386 * When called from perf_event_exit_task, it's OK because the 2387 * context has been detached from its task. 2388 */ 2389 static void perf_remove_from_context(struct perf_event *event, unsigned long flags) 2390 { 2391 struct perf_event_context *ctx = event->ctx; 2392 2393 lockdep_assert_held(&ctx->mutex); 2394 2395 /* 2396 * Because of perf_event_exit_task(), perf_remove_from_context() ought 2397 * to work in the face of TASK_TOMBSTONE, unlike every other 2398 * event_function_call() user. 2399 */ 2400 raw_spin_lock_irq(&ctx->lock); 2401 /* 2402 * Cgroup events are per-cpu events, and must IPI because of 2403 * cgrp_cpuctx_list. 2404 */ 2405 if (!ctx->is_active && !is_cgroup_event(event)) { 2406 __perf_remove_from_context(event, __get_cpu_context(ctx), 2407 ctx, (void *)flags); 2408 raw_spin_unlock_irq(&ctx->lock); 2409 return; 2410 } 2411 raw_spin_unlock_irq(&ctx->lock); 2412 2413 event_function_call(event, __perf_remove_from_context, (void *)flags); 2414 } 2415 2416 /* 2417 * Cross CPU call to disable a performance event 2418 */ 2419 static void __perf_event_disable(struct perf_event *event, 2420 struct perf_cpu_context *cpuctx, 2421 struct perf_event_context *ctx, 2422 void *info) 2423 { 2424 if (event->state < PERF_EVENT_STATE_INACTIVE) 2425 return; 2426 2427 if (ctx->is_active & EVENT_TIME) { 2428 update_context_time(ctx); 2429 update_cgrp_time_from_event(event); 2430 } 2431 2432 if (event == event->group_leader) 2433 group_sched_out(event, cpuctx, ctx); 2434 else 2435 event_sched_out(event, cpuctx, ctx); 2436 2437 perf_event_set_state(event, PERF_EVENT_STATE_OFF); 2438 perf_cgroup_event_disable(event, ctx); 2439 } 2440 2441 /* 2442 * Disable an event. 2443 * 2444 * If event->ctx is a cloned context, callers must make sure that 2445 * every task struct that event->ctx->task could possibly point to 2446 * remains valid. This condition is satisfied when called through 2447 * perf_event_for_each_child or perf_event_for_each because they 2448 * hold the top-level event's child_mutex, so any descendant that 2449 * goes to exit will block in perf_event_exit_event(). 2450 * 2451 * When called from perf_pending_irq it's OK because event->ctx 2452 * is the current context on this CPU and preemption is disabled, 2453 * hence we can't get into perf_event_task_sched_out for this context. 2454 */ 2455 static void _perf_event_disable(struct perf_event *event) 2456 { 2457 struct perf_event_context *ctx = event->ctx; 2458 2459 raw_spin_lock_irq(&ctx->lock); 2460 if (event->state <= PERF_EVENT_STATE_OFF) { 2461 raw_spin_unlock_irq(&ctx->lock); 2462 return; 2463 } 2464 raw_spin_unlock_irq(&ctx->lock); 2465 2466 event_function_call(event, __perf_event_disable, NULL); 2467 } 2468 2469 void perf_event_disable_local(struct perf_event *event) 2470 { 2471 event_function_local(event, __perf_event_disable, NULL); 2472 } 2473 2474 /* 2475 * Strictly speaking kernel users cannot create groups and therefore this 2476 * interface does not need the perf_event_ctx_lock() magic. 2477 */ 2478 void perf_event_disable(struct perf_event *event) 2479 { 2480 struct perf_event_context *ctx; 2481 2482 ctx = perf_event_ctx_lock(event); 2483 _perf_event_disable(event); 2484 perf_event_ctx_unlock(event, ctx); 2485 } 2486 EXPORT_SYMBOL_GPL(perf_event_disable); 2487 2488 void perf_event_disable_inatomic(struct perf_event *event) 2489 { 2490 event->pending_disable = 1; 2491 irq_work_queue(&event->pending_irq); 2492 } 2493 2494 #define MAX_INTERRUPTS (~0ULL) 2495 2496 static void perf_log_throttle(struct perf_event *event, int enable); 2497 static void perf_log_itrace_start(struct perf_event *event); 2498 2499 static int 2500 event_sched_in(struct perf_event *event, 2501 struct perf_cpu_context *cpuctx, 2502 struct perf_event_context *ctx) 2503 { 2504 int ret = 0; 2505 2506 WARN_ON_ONCE(event->ctx != ctx); 2507 2508 lockdep_assert_held(&ctx->lock); 2509 2510 if (event->state <= PERF_EVENT_STATE_OFF) 2511 return 0; 2512 2513 WRITE_ONCE(event->oncpu, smp_processor_id()); 2514 /* 2515 * Order event::oncpu write to happen before the ACTIVE state is 2516 * visible. This allows perf_event_{stop,read}() to observe the correct 2517 * ->oncpu if it sees ACTIVE. 2518 */ 2519 smp_wmb(); 2520 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE); 2521 2522 /* 2523 * Unthrottle events, since we scheduled we might have missed several 2524 * ticks already, also for a heavily scheduling task there is little 2525 * guarantee it'll get a tick in a timely manner. 2526 */ 2527 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) { 2528 perf_log_throttle(event, 1); 2529 event->hw.interrupts = 0; 2530 } 2531 2532 perf_pmu_disable(event->pmu); 2533 2534 perf_log_itrace_start(event); 2535 2536 if (event->pmu->add(event, PERF_EF_START)) { 2537 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE); 2538 event->oncpu = -1; 2539 ret = -EAGAIN; 2540 goto out; 2541 } 2542 2543 if (!is_software_event(event)) 2544 cpuctx->active_oncpu++; 2545 if (!ctx->nr_active++) 2546 perf_event_ctx_activate(ctx); 2547 if (event->attr.freq && event->attr.sample_freq) 2548 ctx->nr_freq++; 2549 2550 if (event->attr.exclusive) 2551 cpuctx->exclusive = 1; 2552 2553 out: 2554 perf_pmu_enable(event->pmu); 2555 2556 return ret; 2557 } 2558 2559 static int 2560 group_sched_in(struct perf_event *group_event, 2561 struct perf_cpu_context *cpuctx, 2562 struct perf_event_context *ctx) 2563 { 2564 struct perf_event *event, *partial_group = NULL; 2565 struct pmu *pmu = ctx->pmu; 2566 2567 if (group_event->state == PERF_EVENT_STATE_OFF) 2568 return 0; 2569 2570 pmu->start_txn(pmu, PERF_PMU_TXN_ADD); 2571 2572 if (event_sched_in(group_event, cpuctx, ctx)) 2573 goto error; 2574 2575 /* 2576 * Schedule in siblings as one group (if any): 2577 */ 2578 for_each_sibling_event(event, group_event) { 2579 if (event_sched_in(event, cpuctx, ctx)) { 2580 partial_group = event; 2581 goto group_error; 2582 } 2583 } 2584 2585 if (!pmu->commit_txn(pmu)) 2586 return 0; 2587 2588 group_error: 2589 /* 2590 * Groups can be scheduled in as one unit only, so undo any 2591 * partial group before returning: 2592 * The events up to the failed event are scheduled out normally. 2593 */ 2594 for_each_sibling_event(event, group_event) { 2595 if (event == partial_group) 2596 break; 2597 2598 event_sched_out(event, cpuctx, ctx); 2599 } 2600 event_sched_out(group_event, cpuctx, ctx); 2601 2602 error: 2603 pmu->cancel_txn(pmu); 2604 return -EAGAIN; 2605 } 2606 2607 /* 2608 * Work out whether we can put this event group on the CPU now. 2609 */ 2610 static int group_can_go_on(struct perf_event *event, 2611 struct perf_cpu_context *cpuctx, 2612 int can_add_hw) 2613 { 2614 /* 2615 * Groups consisting entirely of software events can always go on. 2616 */ 2617 if (event->group_caps & PERF_EV_CAP_SOFTWARE) 2618 return 1; 2619 /* 2620 * If an exclusive group is already on, no other hardware 2621 * events can go on. 2622 */ 2623 if (cpuctx->exclusive) 2624 return 0; 2625 /* 2626 * If this group is exclusive and there are already 2627 * events on the CPU, it can't go on. 2628 */ 2629 if (event->attr.exclusive && !list_empty(get_event_list(event))) 2630 return 0; 2631 /* 2632 * Otherwise, try to add it if all previous groups were able 2633 * to go on. 2634 */ 2635 return can_add_hw; 2636 } 2637 2638 static void add_event_to_ctx(struct perf_event *event, 2639 struct perf_event_context *ctx) 2640 { 2641 list_add_event(event, ctx); 2642 perf_group_attach(event); 2643 } 2644 2645 static void ctx_sched_out(struct perf_event_context *ctx, 2646 struct perf_cpu_context *cpuctx, 2647 enum event_type_t event_type); 2648 static void 2649 ctx_sched_in(struct perf_event_context *ctx, 2650 struct perf_cpu_context *cpuctx, 2651 enum event_type_t event_type); 2652 2653 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx, 2654 struct perf_event_context *ctx, 2655 enum event_type_t event_type) 2656 { 2657 if (!cpuctx->task_ctx) 2658 return; 2659 2660 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx)) 2661 return; 2662 2663 ctx_sched_out(ctx, cpuctx, event_type); 2664 } 2665 2666 static void perf_event_sched_in(struct perf_cpu_context *cpuctx, 2667 struct perf_event_context *ctx) 2668 { 2669 cpu_ctx_sched_in(cpuctx, EVENT_PINNED); 2670 if (ctx) 2671 ctx_sched_in(ctx, cpuctx, EVENT_PINNED); 2672 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE); 2673 if (ctx) 2674 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE); 2675 } 2676 2677 /* 2678 * We want to maintain the following priority of scheduling: 2679 * - CPU pinned (EVENT_CPU | EVENT_PINNED) 2680 * - task pinned (EVENT_PINNED) 2681 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE) 2682 * - task flexible (EVENT_FLEXIBLE). 2683 * 2684 * In order to avoid unscheduling and scheduling back in everything every 2685 * time an event is added, only do it for the groups of equal priority and 2686 * below. 2687 * 2688 * This can be called after a batch operation on task events, in which case 2689 * event_type is a bit mask of the types of events involved. For CPU events, 2690 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE. 2691 */ 2692 static void ctx_resched(struct perf_cpu_context *cpuctx, 2693 struct perf_event_context *task_ctx, 2694 enum event_type_t event_type) 2695 { 2696 enum event_type_t ctx_event_type; 2697 bool cpu_event = !!(event_type & EVENT_CPU); 2698 2699 /* 2700 * If pinned groups are involved, flexible groups also need to be 2701 * scheduled out. 2702 */ 2703 if (event_type & EVENT_PINNED) 2704 event_type |= EVENT_FLEXIBLE; 2705 2706 ctx_event_type = event_type & EVENT_ALL; 2707 2708 perf_pmu_disable(cpuctx->ctx.pmu); 2709 if (task_ctx) 2710 task_ctx_sched_out(cpuctx, task_ctx, event_type); 2711 2712 /* 2713 * Decide which cpu ctx groups to schedule out based on the types 2714 * of events that caused rescheduling: 2715 * - EVENT_CPU: schedule out corresponding groups; 2716 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups; 2717 * - otherwise, do nothing more. 2718 */ 2719 if (cpu_event) 2720 cpu_ctx_sched_out(cpuctx, ctx_event_type); 2721 else if (ctx_event_type & EVENT_PINNED) 2722 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); 2723 2724 perf_event_sched_in(cpuctx, task_ctx); 2725 perf_pmu_enable(cpuctx->ctx.pmu); 2726 } 2727 2728 void perf_pmu_resched(struct pmu *pmu) 2729 { 2730 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 2731 struct perf_event_context *task_ctx = cpuctx->task_ctx; 2732 2733 perf_ctx_lock(cpuctx, task_ctx); 2734 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU); 2735 perf_ctx_unlock(cpuctx, task_ctx); 2736 } 2737 2738 /* 2739 * Cross CPU call to install and enable a performance event 2740 * 2741 * Very similar to remote_function() + event_function() but cannot assume that 2742 * things like ctx->is_active and cpuctx->task_ctx are set. 2743 */ 2744 static int __perf_install_in_context(void *info) 2745 { 2746 struct perf_event *event = info; 2747 struct perf_event_context *ctx = event->ctx; 2748 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 2749 struct perf_event_context *task_ctx = cpuctx->task_ctx; 2750 bool reprogram = true; 2751 int ret = 0; 2752 2753 raw_spin_lock(&cpuctx->ctx.lock); 2754 if (ctx->task) { 2755 raw_spin_lock(&ctx->lock); 2756 task_ctx = ctx; 2757 2758 reprogram = (ctx->task == current); 2759 2760 /* 2761 * If the task is running, it must be running on this CPU, 2762 * otherwise we cannot reprogram things. 2763 * 2764 * If its not running, we don't care, ctx->lock will 2765 * serialize against it becoming runnable. 2766 */ 2767 if (task_curr(ctx->task) && !reprogram) { 2768 ret = -ESRCH; 2769 goto unlock; 2770 } 2771 2772 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx); 2773 } else if (task_ctx) { 2774 raw_spin_lock(&task_ctx->lock); 2775 } 2776 2777 #ifdef CONFIG_CGROUP_PERF 2778 if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) { 2779 /* 2780 * If the current cgroup doesn't match the event's 2781 * cgroup, we should not try to schedule it. 2782 */ 2783 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx); 2784 reprogram = cgroup_is_descendant(cgrp->css.cgroup, 2785 event->cgrp->css.cgroup); 2786 } 2787 #endif 2788 2789 if (reprogram) { 2790 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 2791 add_event_to_ctx(event, ctx); 2792 ctx_resched(cpuctx, task_ctx, get_event_type(event)); 2793 } else { 2794 add_event_to_ctx(event, ctx); 2795 } 2796 2797 unlock: 2798 perf_ctx_unlock(cpuctx, task_ctx); 2799 2800 return ret; 2801 } 2802 2803 static bool exclusive_event_installable(struct perf_event *event, 2804 struct perf_event_context *ctx); 2805 2806 /* 2807 * Attach a performance event to a context. 2808 * 2809 * Very similar to event_function_call, see comment there. 2810 */ 2811 static void 2812 perf_install_in_context(struct perf_event_context *ctx, 2813 struct perf_event *event, 2814 int cpu) 2815 { 2816 struct task_struct *task = READ_ONCE(ctx->task); 2817 2818 lockdep_assert_held(&ctx->mutex); 2819 2820 WARN_ON_ONCE(!exclusive_event_installable(event, ctx)); 2821 2822 if (event->cpu != -1) 2823 event->cpu = cpu; 2824 2825 /* 2826 * Ensures that if we can observe event->ctx, both the event and ctx 2827 * will be 'complete'. See perf_iterate_sb_cpu(). 2828 */ 2829 smp_store_release(&event->ctx, ctx); 2830 2831 /* 2832 * perf_event_attr::disabled events will not run and can be initialized 2833 * without IPI. Except when this is the first event for the context, in 2834 * that case we need the magic of the IPI to set ctx->is_active. 2835 * Similarly, cgroup events for the context also needs the IPI to 2836 * manipulate the cgrp_cpuctx_list. 2837 * 2838 * The IOC_ENABLE that is sure to follow the creation of a disabled 2839 * event will issue the IPI and reprogram the hardware. 2840 */ 2841 if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF && 2842 ctx->nr_events && !is_cgroup_event(event)) { 2843 raw_spin_lock_irq(&ctx->lock); 2844 if (ctx->task == TASK_TOMBSTONE) { 2845 raw_spin_unlock_irq(&ctx->lock); 2846 return; 2847 } 2848 add_event_to_ctx(event, ctx); 2849 raw_spin_unlock_irq(&ctx->lock); 2850 return; 2851 } 2852 2853 if (!task) { 2854 cpu_function_call(cpu, __perf_install_in_context, event); 2855 return; 2856 } 2857 2858 /* 2859 * Should not happen, we validate the ctx is still alive before calling. 2860 */ 2861 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) 2862 return; 2863 2864 /* 2865 * Installing events is tricky because we cannot rely on ctx->is_active 2866 * to be set in case this is the nr_events 0 -> 1 transition. 2867 * 2868 * Instead we use task_curr(), which tells us if the task is running. 2869 * However, since we use task_curr() outside of rq::lock, we can race 2870 * against the actual state. This means the result can be wrong. 2871 * 2872 * If we get a false positive, we retry, this is harmless. 2873 * 2874 * If we get a false negative, things are complicated. If we are after 2875 * perf_event_context_sched_in() ctx::lock will serialize us, and the 2876 * value must be correct. If we're before, it doesn't matter since 2877 * perf_event_context_sched_in() will program the counter. 2878 * 2879 * However, this hinges on the remote context switch having observed 2880 * our task->perf_event_ctxp[] store, such that it will in fact take 2881 * ctx::lock in perf_event_context_sched_in(). 2882 * 2883 * We do this by task_function_call(), if the IPI fails to hit the task 2884 * we know any future context switch of task must see the 2885 * perf_event_ctpx[] store. 2886 */ 2887 2888 /* 2889 * This smp_mb() orders the task->perf_event_ctxp[] store with the 2890 * task_cpu() load, such that if the IPI then does not find the task 2891 * running, a future context switch of that task must observe the 2892 * store. 2893 */ 2894 smp_mb(); 2895 again: 2896 if (!task_function_call(task, __perf_install_in_context, event)) 2897 return; 2898 2899 raw_spin_lock_irq(&ctx->lock); 2900 task = ctx->task; 2901 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) { 2902 /* 2903 * Cannot happen because we already checked above (which also 2904 * cannot happen), and we hold ctx->mutex, which serializes us 2905 * against perf_event_exit_task_context(). 2906 */ 2907 raw_spin_unlock_irq(&ctx->lock); 2908 return; 2909 } 2910 /* 2911 * If the task is not running, ctx->lock will avoid it becoming so, 2912 * thus we can safely install the event. 2913 */ 2914 if (task_curr(task)) { 2915 raw_spin_unlock_irq(&ctx->lock); 2916 goto again; 2917 } 2918 add_event_to_ctx(event, ctx); 2919 raw_spin_unlock_irq(&ctx->lock); 2920 } 2921 2922 /* 2923 * Cross CPU call to enable a performance event 2924 */ 2925 static void __perf_event_enable(struct perf_event *event, 2926 struct perf_cpu_context *cpuctx, 2927 struct perf_event_context *ctx, 2928 void *info) 2929 { 2930 struct perf_event *leader = event->group_leader; 2931 struct perf_event_context *task_ctx; 2932 2933 if (event->state >= PERF_EVENT_STATE_INACTIVE || 2934 event->state <= PERF_EVENT_STATE_ERROR) 2935 return; 2936 2937 if (ctx->is_active) 2938 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 2939 2940 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE); 2941 perf_cgroup_event_enable(event, ctx); 2942 2943 if (!ctx->is_active) 2944 return; 2945 2946 if (!event_filter_match(event)) { 2947 ctx_sched_in(ctx, cpuctx, EVENT_TIME); 2948 return; 2949 } 2950 2951 /* 2952 * If the event is in a group and isn't the group leader, 2953 * then don't put it on unless the group is on. 2954 */ 2955 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) { 2956 ctx_sched_in(ctx, cpuctx, EVENT_TIME); 2957 return; 2958 } 2959 2960 task_ctx = cpuctx->task_ctx; 2961 if (ctx->task) 2962 WARN_ON_ONCE(task_ctx != ctx); 2963 2964 ctx_resched(cpuctx, task_ctx, get_event_type(event)); 2965 } 2966 2967 /* 2968 * Enable an event. 2969 * 2970 * If event->ctx is a cloned context, callers must make sure that 2971 * every task struct that event->ctx->task could possibly point to 2972 * remains valid. This condition is satisfied when called through 2973 * perf_event_for_each_child or perf_event_for_each as described 2974 * for perf_event_disable. 2975 */ 2976 static void _perf_event_enable(struct perf_event *event) 2977 { 2978 struct perf_event_context *ctx = event->ctx; 2979 2980 raw_spin_lock_irq(&ctx->lock); 2981 if (event->state >= PERF_EVENT_STATE_INACTIVE || 2982 event->state < PERF_EVENT_STATE_ERROR) { 2983 out: 2984 raw_spin_unlock_irq(&ctx->lock); 2985 return; 2986 } 2987 2988 /* 2989 * If the event is in error state, clear that first. 2990 * 2991 * That way, if we see the event in error state below, we know that it 2992 * has gone back into error state, as distinct from the task having 2993 * been scheduled away before the cross-call arrived. 2994 */ 2995 if (event->state == PERF_EVENT_STATE_ERROR) { 2996 /* 2997 * Detached SIBLING events cannot leave ERROR state. 2998 */ 2999 if (event->event_caps & PERF_EV_CAP_SIBLING && 3000 event->group_leader == event) 3001 goto out; 3002 3003 event->state = PERF_EVENT_STATE_OFF; 3004 } 3005 raw_spin_unlock_irq(&ctx->lock); 3006 3007 event_function_call(event, __perf_event_enable, NULL); 3008 } 3009 3010 /* 3011 * See perf_event_disable(); 3012 */ 3013 void perf_event_enable(struct perf_event *event) 3014 { 3015 struct perf_event_context *ctx; 3016 3017 ctx = perf_event_ctx_lock(event); 3018 _perf_event_enable(event); 3019 perf_event_ctx_unlock(event, ctx); 3020 } 3021 EXPORT_SYMBOL_GPL(perf_event_enable); 3022 3023 struct stop_event_data { 3024 struct perf_event *event; 3025 unsigned int restart; 3026 }; 3027 3028 static int __perf_event_stop(void *info) 3029 { 3030 struct stop_event_data *sd = info; 3031 struct perf_event *event = sd->event; 3032 3033 /* if it's already INACTIVE, do nothing */ 3034 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) 3035 return 0; 3036 3037 /* matches smp_wmb() in event_sched_in() */ 3038 smp_rmb(); 3039 3040 /* 3041 * There is a window with interrupts enabled before we get here, 3042 * so we need to check again lest we try to stop another CPU's event. 3043 */ 3044 if (READ_ONCE(event->oncpu) != smp_processor_id()) 3045 return -EAGAIN; 3046 3047 event->pmu->stop(event, PERF_EF_UPDATE); 3048 3049 /* 3050 * May race with the actual stop (through perf_pmu_output_stop()), 3051 * but it is only used for events with AUX ring buffer, and such 3052 * events will refuse to restart because of rb::aux_mmap_count==0, 3053 * see comments in perf_aux_output_begin(). 3054 * 3055 * Since this is happening on an event-local CPU, no trace is lost 3056 * while restarting. 3057 */ 3058 if (sd->restart) 3059 event->pmu->start(event, 0); 3060 3061 return 0; 3062 } 3063 3064 static int perf_event_stop(struct perf_event *event, int restart) 3065 { 3066 struct stop_event_data sd = { 3067 .event = event, 3068 .restart = restart, 3069 }; 3070 int ret = 0; 3071 3072 do { 3073 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE) 3074 return 0; 3075 3076 /* matches smp_wmb() in event_sched_in() */ 3077 smp_rmb(); 3078 3079 /* 3080 * We only want to restart ACTIVE events, so if the event goes 3081 * inactive here (event->oncpu==-1), there's nothing more to do; 3082 * fall through with ret==-ENXIO. 3083 */ 3084 ret = cpu_function_call(READ_ONCE(event->oncpu), 3085 __perf_event_stop, &sd); 3086 } while (ret == -EAGAIN); 3087 3088 return ret; 3089 } 3090 3091 /* 3092 * In order to contain the amount of racy and tricky in the address filter 3093 * configuration management, it is a two part process: 3094 * 3095 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below, 3096 * we update the addresses of corresponding vmas in 3097 * event::addr_filter_ranges array and bump the event::addr_filters_gen; 3098 * (p2) when an event is scheduled in (pmu::add), it calls 3099 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync() 3100 * if the generation has changed since the previous call. 3101 * 3102 * If (p1) happens while the event is active, we restart it to force (p2). 3103 * 3104 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on 3105 * pre-existing mappings, called once when new filters arrive via SET_FILTER 3106 * ioctl; 3107 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly 3108 * registered mapping, called for every new mmap(), with mm::mmap_lock down 3109 * for reading; 3110 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process 3111 * of exec. 3112 */ 3113 void perf_event_addr_filters_sync(struct perf_event *event) 3114 { 3115 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 3116 3117 if (!has_addr_filter(event)) 3118 return; 3119 3120 raw_spin_lock(&ifh->lock); 3121 if (event->addr_filters_gen != event->hw.addr_filters_gen) { 3122 event->pmu->addr_filters_sync(event); 3123 event->hw.addr_filters_gen = event->addr_filters_gen; 3124 } 3125 raw_spin_unlock(&ifh->lock); 3126 } 3127 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync); 3128 3129 static int _perf_event_refresh(struct perf_event *event, int refresh) 3130 { 3131 /* 3132 * not supported on inherited events 3133 */ 3134 if (event->attr.inherit || !is_sampling_event(event)) 3135 return -EINVAL; 3136 3137 atomic_add(refresh, &event->event_limit); 3138 _perf_event_enable(event); 3139 3140 return 0; 3141 } 3142 3143 /* 3144 * See perf_event_disable() 3145 */ 3146 int perf_event_refresh(struct perf_event *event, int refresh) 3147 { 3148 struct perf_event_context *ctx; 3149 int ret; 3150 3151 ctx = perf_event_ctx_lock(event); 3152 ret = _perf_event_refresh(event, refresh); 3153 perf_event_ctx_unlock(event, ctx); 3154 3155 return ret; 3156 } 3157 EXPORT_SYMBOL_GPL(perf_event_refresh); 3158 3159 static int perf_event_modify_breakpoint(struct perf_event *bp, 3160 struct perf_event_attr *attr) 3161 { 3162 int err; 3163 3164 _perf_event_disable(bp); 3165 3166 err = modify_user_hw_breakpoint_check(bp, attr, true); 3167 3168 if (!bp->attr.disabled) 3169 _perf_event_enable(bp); 3170 3171 return err; 3172 } 3173 3174 /* 3175 * Copy event-type-independent attributes that may be modified. 3176 */ 3177 static void perf_event_modify_copy_attr(struct perf_event_attr *to, 3178 const struct perf_event_attr *from) 3179 { 3180 to->sig_data = from->sig_data; 3181 } 3182 3183 static int perf_event_modify_attr(struct perf_event *event, 3184 struct perf_event_attr *attr) 3185 { 3186 int (*func)(struct perf_event *, struct perf_event_attr *); 3187 struct perf_event *child; 3188 int err; 3189 3190 if (event->attr.type != attr->type) 3191 return -EINVAL; 3192 3193 switch (event->attr.type) { 3194 case PERF_TYPE_BREAKPOINT: 3195 func = perf_event_modify_breakpoint; 3196 break; 3197 default: 3198 /* Place holder for future additions. */ 3199 return -EOPNOTSUPP; 3200 } 3201 3202 WARN_ON_ONCE(event->ctx->parent_ctx); 3203 3204 mutex_lock(&event->child_mutex); 3205 /* 3206 * Event-type-independent attributes must be copied before event-type 3207 * modification, which will validate that final attributes match the 3208 * source attributes after all relevant attributes have been copied. 3209 */ 3210 perf_event_modify_copy_attr(&event->attr, attr); 3211 err = func(event, attr); 3212 if (err) 3213 goto out; 3214 list_for_each_entry(child, &event->child_list, child_list) { 3215 perf_event_modify_copy_attr(&child->attr, attr); 3216 err = func(child, attr); 3217 if (err) 3218 goto out; 3219 } 3220 out: 3221 mutex_unlock(&event->child_mutex); 3222 return err; 3223 } 3224 3225 static void ctx_sched_out(struct perf_event_context *ctx, 3226 struct perf_cpu_context *cpuctx, 3227 enum event_type_t event_type) 3228 { 3229 struct perf_event *event, *tmp; 3230 int is_active = ctx->is_active; 3231 3232 lockdep_assert_held(&ctx->lock); 3233 3234 if (likely(!ctx->nr_events)) { 3235 /* 3236 * See __perf_remove_from_context(). 3237 */ 3238 WARN_ON_ONCE(ctx->is_active); 3239 if (ctx->task) 3240 WARN_ON_ONCE(cpuctx->task_ctx); 3241 return; 3242 } 3243 3244 /* 3245 * Always update time if it was set; not only when it changes. 3246 * Otherwise we can 'forget' to update time for any but the last 3247 * context we sched out. For example: 3248 * 3249 * ctx_sched_out(.event_type = EVENT_FLEXIBLE) 3250 * ctx_sched_out(.event_type = EVENT_PINNED) 3251 * 3252 * would only update time for the pinned events. 3253 */ 3254 if (is_active & EVENT_TIME) { 3255 /* update (and stop) ctx time */ 3256 update_context_time(ctx); 3257 update_cgrp_time_from_cpuctx(cpuctx, ctx == &cpuctx->ctx); 3258 /* 3259 * CPU-release for the below ->is_active store, 3260 * see __load_acquire() in perf_event_time_now() 3261 */ 3262 barrier(); 3263 } 3264 3265 ctx->is_active &= ~event_type; 3266 if (!(ctx->is_active & EVENT_ALL)) 3267 ctx->is_active = 0; 3268 3269 if (ctx->task) { 3270 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 3271 if (!ctx->is_active) 3272 cpuctx->task_ctx = NULL; 3273 } 3274 3275 is_active ^= ctx->is_active; /* changed bits */ 3276 3277 if (!ctx->nr_active || !(is_active & EVENT_ALL)) 3278 return; 3279 3280 perf_pmu_disable(ctx->pmu); 3281 if (is_active & EVENT_PINNED) { 3282 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list) 3283 group_sched_out(event, cpuctx, ctx); 3284 } 3285 3286 if (is_active & EVENT_FLEXIBLE) { 3287 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list) 3288 group_sched_out(event, cpuctx, ctx); 3289 3290 /* 3291 * Since we cleared EVENT_FLEXIBLE, also clear 3292 * rotate_necessary, is will be reset by 3293 * ctx_flexible_sched_in() when needed. 3294 */ 3295 ctx->rotate_necessary = 0; 3296 } 3297 perf_pmu_enable(ctx->pmu); 3298 } 3299 3300 /* 3301 * Test whether two contexts are equivalent, i.e. whether they have both been 3302 * cloned from the same version of the same context. 3303 * 3304 * Equivalence is measured using a generation number in the context that is 3305 * incremented on each modification to it; see unclone_ctx(), list_add_event() 3306 * and list_del_event(). 3307 */ 3308 static int context_equiv(struct perf_event_context *ctx1, 3309 struct perf_event_context *ctx2) 3310 { 3311 lockdep_assert_held(&ctx1->lock); 3312 lockdep_assert_held(&ctx2->lock); 3313 3314 /* Pinning disables the swap optimization */ 3315 if (ctx1->pin_count || ctx2->pin_count) 3316 return 0; 3317 3318 /* If ctx1 is the parent of ctx2 */ 3319 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen) 3320 return 1; 3321 3322 /* If ctx2 is the parent of ctx1 */ 3323 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation) 3324 return 1; 3325 3326 /* 3327 * If ctx1 and ctx2 have the same parent; we flatten the parent 3328 * hierarchy, see perf_event_init_context(). 3329 */ 3330 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx && 3331 ctx1->parent_gen == ctx2->parent_gen) 3332 return 1; 3333 3334 /* Unmatched */ 3335 return 0; 3336 } 3337 3338 static void __perf_event_sync_stat(struct perf_event *event, 3339 struct perf_event *next_event) 3340 { 3341 u64 value; 3342 3343 if (!event->attr.inherit_stat) 3344 return; 3345 3346 /* 3347 * Update the event value, we cannot use perf_event_read() 3348 * because we're in the middle of a context switch and have IRQs 3349 * disabled, which upsets smp_call_function_single(), however 3350 * we know the event must be on the current CPU, therefore we 3351 * don't need to use it. 3352 */ 3353 if (event->state == PERF_EVENT_STATE_ACTIVE) 3354 event->pmu->read(event); 3355 3356 perf_event_update_time(event); 3357 3358 /* 3359 * In order to keep per-task stats reliable we need to flip the event 3360 * values when we flip the contexts. 3361 */ 3362 value = local64_read(&next_event->count); 3363 value = local64_xchg(&event->count, value); 3364 local64_set(&next_event->count, value); 3365 3366 swap(event->total_time_enabled, next_event->total_time_enabled); 3367 swap(event->total_time_running, next_event->total_time_running); 3368 3369 /* 3370 * Since we swizzled the values, update the user visible data too. 3371 */ 3372 perf_event_update_userpage(event); 3373 perf_event_update_userpage(next_event); 3374 } 3375 3376 static void perf_event_sync_stat(struct perf_event_context *ctx, 3377 struct perf_event_context *next_ctx) 3378 { 3379 struct perf_event *event, *next_event; 3380 3381 if (!ctx->nr_stat) 3382 return; 3383 3384 update_context_time(ctx); 3385 3386 event = list_first_entry(&ctx->event_list, 3387 struct perf_event, event_entry); 3388 3389 next_event = list_first_entry(&next_ctx->event_list, 3390 struct perf_event, event_entry); 3391 3392 while (&event->event_entry != &ctx->event_list && 3393 &next_event->event_entry != &next_ctx->event_list) { 3394 3395 __perf_event_sync_stat(event, next_event); 3396 3397 event = list_next_entry(event, event_entry); 3398 next_event = list_next_entry(next_event, event_entry); 3399 } 3400 } 3401 3402 static void perf_event_context_sched_out(struct task_struct *task, int ctxn, 3403 struct task_struct *next) 3404 { 3405 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn]; 3406 struct perf_event_context *next_ctx; 3407 struct perf_event_context *parent, *next_parent; 3408 struct perf_cpu_context *cpuctx; 3409 int do_switch = 1; 3410 struct pmu *pmu; 3411 3412 if (likely(!ctx)) 3413 return; 3414 3415 pmu = ctx->pmu; 3416 cpuctx = __get_cpu_context(ctx); 3417 if (!cpuctx->task_ctx) 3418 return; 3419 3420 rcu_read_lock(); 3421 next_ctx = next->perf_event_ctxp[ctxn]; 3422 if (!next_ctx) 3423 goto unlock; 3424 3425 parent = rcu_dereference(ctx->parent_ctx); 3426 next_parent = rcu_dereference(next_ctx->parent_ctx); 3427 3428 /* If neither context have a parent context; they cannot be clones. */ 3429 if (!parent && !next_parent) 3430 goto unlock; 3431 3432 if (next_parent == ctx || next_ctx == parent || next_parent == parent) { 3433 /* 3434 * Looks like the two contexts are clones, so we might be 3435 * able to optimize the context switch. We lock both 3436 * contexts and check that they are clones under the 3437 * lock (including re-checking that neither has been 3438 * uncloned in the meantime). It doesn't matter which 3439 * order we take the locks because no other cpu could 3440 * be trying to lock both of these tasks. 3441 */ 3442 raw_spin_lock(&ctx->lock); 3443 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING); 3444 if (context_equiv(ctx, next_ctx)) { 3445 3446 perf_pmu_disable(pmu); 3447 3448 /* PMIs are disabled; ctx->nr_pending is stable. */ 3449 if (local_read(&ctx->nr_pending) || 3450 local_read(&next_ctx->nr_pending)) { 3451 /* 3452 * Must not swap out ctx when there's pending 3453 * events that rely on the ctx->task relation. 3454 */ 3455 raw_spin_unlock(&next_ctx->lock); 3456 rcu_read_unlock(); 3457 goto inside_switch; 3458 } 3459 3460 WRITE_ONCE(ctx->task, next); 3461 WRITE_ONCE(next_ctx->task, task); 3462 3463 if (cpuctx->sched_cb_usage && pmu->sched_task) 3464 pmu->sched_task(ctx, false); 3465 3466 /* 3467 * PMU specific parts of task perf context can require 3468 * additional synchronization. As an example of such 3469 * synchronization see implementation details of Intel 3470 * LBR call stack data profiling; 3471 */ 3472 if (pmu->swap_task_ctx) 3473 pmu->swap_task_ctx(ctx, next_ctx); 3474 else 3475 swap(ctx->task_ctx_data, next_ctx->task_ctx_data); 3476 3477 perf_pmu_enable(pmu); 3478 3479 /* 3480 * RCU_INIT_POINTER here is safe because we've not 3481 * modified the ctx and the above modification of 3482 * ctx->task and ctx->task_ctx_data are immaterial 3483 * since those values are always verified under 3484 * ctx->lock which we're now holding. 3485 */ 3486 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx); 3487 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx); 3488 3489 do_switch = 0; 3490 3491 perf_event_sync_stat(ctx, next_ctx); 3492 } 3493 raw_spin_unlock(&next_ctx->lock); 3494 raw_spin_unlock(&ctx->lock); 3495 } 3496 unlock: 3497 rcu_read_unlock(); 3498 3499 if (do_switch) { 3500 raw_spin_lock(&ctx->lock); 3501 perf_pmu_disable(pmu); 3502 3503 inside_switch: 3504 if (cpuctx->sched_cb_usage && pmu->sched_task) 3505 pmu->sched_task(ctx, false); 3506 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL); 3507 3508 perf_pmu_enable(pmu); 3509 raw_spin_unlock(&ctx->lock); 3510 } 3511 } 3512 3513 static DEFINE_PER_CPU(struct list_head, sched_cb_list); 3514 3515 void perf_sched_cb_dec(struct pmu *pmu) 3516 { 3517 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 3518 3519 this_cpu_dec(perf_sched_cb_usages); 3520 3521 if (!--cpuctx->sched_cb_usage) 3522 list_del(&cpuctx->sched_cb_entry); 3523 } 3524 3525 3526 void perf_sched_cb_inc(struct pmu *pmu) 3527 { 3528 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 3529 3530 if (!cpuctx->sched_cb_usage++) 3531 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list)); 3532 3533 this_cpu_inc(perf_sched_cb_usages); 3534 } 3535 3536 /* 3537 * This function provides the context switch callback to the lower code 3538 * layer. It is invoked ONLY when the context switch callback is enabled. 3539 * 3540 * This callback is relevant even to per-cpu events; for example multi event 3541 * PEBS requires this to provide PID/TID information. This requires we flush 3542 * all queued PEBS records before we context switch to a new task. 3543 */ 3544 static void __perf_pmu_sched_task(struct perf_cpu_context *cpuctx, bool sched_in) 3545 { 3546 struct pmu *pmu; 3547 3548 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */ 3549 3550 if (WARN_ON_ONCE(!pmu->sched_task)) 3551 return; 3552 3553 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 3554 perf_pmu_disable(pmu); 3555 3556 pmu->sched_task(cpuctx->task_ctx, sched_in); 3557 3558 perf_pmu_enable(pmu); 3559 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 3560 } 3561 3562 static void perf_pmu_sched_task(struct task_struct *prev, 3563 struct task_struct *next, 3564 bool sched_in) 3565 { 3566 struct perf_cpu_context *cpuctx; 3567 3568 if (prev == next) 3569 return; 3570 3571 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) { 3572 /* will be handled in perf_event_context_sched_in/out */ 3573 if (cpuctx->task_ctx) 3574 continue; 3575 3576 __perf_pmu_sched_task(cpuctx, sched_in); 3577 } 3578 } 3579 3580 static void perf_event_switch(struct task_struct *task, 3581 struct task_struct *next_prev, bool sched_in); 3582 3583 #define for_each_task_context_nr(ctxn) \ 3584 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++) 3585 3586 /* 3587 * Called from scheduler to remove the events of the current task, 3588 * with interrupts disabled. 3589 * 3590 * We stop each event and update the event value in event->count. 3591 * 3592 * This does not protect us against NMI, but disable() 3593 * sets the disabled bit in the control field of event _before_ 3594 * accessing the event control register. If a NMI hits, then it will 3595 * not restart the event. 3596 */ 3597 void __perf_event_task_sched_out(struct task_struct *task, 3598 struct task_struct *next) 3599 { 3600 int ctxn; 3601 3602 if (__this_cpu_read(perf_sched_cb_usages)) 3603 perf_pmu_sched_task(task, next, false); 3604 3605 if (atomic_read(&nr_switch_events)) 3606 perf_event_switch(task, next, false); 3607 3608 for_each_task_context_nr(ctxn) 3609 perf_event_context_sched_out(task, ctxn, next); 3610 3611 /* 3612 * if cgroup events exist on this CPU, then we need 3613 * to check if we have to switch out PMU state. 3614 * cgroup event are system-wide mode only 3615 */ 3616 if (atomic_read(this_cpu_ptr(&perf_cgroup_events))) 3617 perf_cgroup_switch(next); 3618 } 3619 3620 /* 3621 * Called with IRQs disabled 3622 */ 3623 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx, 3624 enum event_type_t event_type) 3625 { 3626 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type); 3627 } 3628 3629 static bool perf_less_group_idx(const void *l, const void *r) 3630 { 3631 const struct perf_event *le = *(const struct perf_event **)l; 3632 const struct perf_event *re = *(const struct perf_event **)r; 3633 3634 return le->group_index < re->group_index; 3635 } 3636 3637 static void swap_ptr(void *l, void *r) 3638 { 3639 void **lp = l, **rp = r; 3640 3641 swap(*lp, *rp); 3642 } 3643 3644 static const struct min_heap_callbacks perf_min_heap = { 3645 .elem_size = sizeof(struct perf_event *), 3646 .less = perf_less_group_idx, 3647 .swp = swap_ptr, 3648 }; 3649 3650 static void __heap_add(struct min_heap *heap, struct perf_event *event) 3651 { 3652 struct perf_event **itrs = heap->data; 3653 3654 if (event) { 3655 itrs[heap->nr] = event; 3656 heap->nr++; 3657 } 3658 } 3659 3660 static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx, 3661 struct perf_event_groups *groups, int cpu, 3662 int (*func)(struct perf_event *, void *), 3663 void *data) 3664 { 3665 #ifdef CONFIG_CGROUP_PERF 3666 struct cgroup_subsys_state *css = NULL; 3667 #endif 3668 /* Space for per CPU and/or any CPU event iterators. */ 3669 struct perf_event *itrs[2]; 3670 struct min_heap event_heap; 3671 struct perf_event **evt; 3672 int ret; 3673 3674 if (cpuctx) { 3675 event_heap = (struct min_heap){ 3676 .data = cpuctx->heap, 3677 .nr = 0, 3678 .size = cpuctx->heap_size, 3679 }; 3680 3681 lockdep_assert_held(&cpuctx->ctx.lock); 3682 3683 #ifdef CONFIG_CGROUP_PERF 3684 if (cpuctx->cgrp) 3685 css = &cpuctx->cgrp->css; 3686 #endif 3687 } else { 3688 event_heap = (struct min_heap){ 3689 .data = itrs, 3690 .nr = 0, 3691 .size = ARRAY_SIZE(itrs), 3692 }; 3693 /* Events not within a CPU context may be on any CPU. */ 3694 __heap_add(&event_heap, perf_event_groups_first(groups, -1, NULL)); 3695 } 3696 evt = event_heap.data; 3697 3698 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, NULL)); 3699 3700 #ifdef CONFIG_CGROUP_PERF 3701 for (; css; css = css->parent) 3702 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, css->cgroup)); 3703 #endif 3704 3705 min_heapify_all(&event_heap, &perf_min_heap); 3706 3707 while (event_heap.nr) { 3708 ret = func(*evt, data); 3709 if (ret) 3710 return ret; 3711 3712 *evt = perf_event_groups_next(*evt); 3713 if (*evt) 3714 min_heapify(&event_heap, 0, &perf_min_heap); 3715 else 3716 min_heap_pop(&event_heap, &perf_min_heap); 3717 } 3718 3719 return 0; 3720 } 3721 3722 /* 3723 * Because the userpage is strictly per-event (there is no concept of context, 3724 * so there cannot be a context indirection), every userpage must be updated 3725 * when context time starts :-( 3726 * 3727 * IOW, we must not miss EVENT_TIME edges. 3728 */ 3729 static inline bool event_update_userpage(struct perf_event *event) 3730 { 3731 if (likely(!atomic_read(&event->mmap_count))) 3732 return false; 3733 3734 perf_event_update_time(event); 3735 perf_event_update_userpage(event); 3736 3737 return true; 3738 } 3739 3740 static inline void group_update_userpage(struct perf_event *group_event) 3741 { 3742 struct perf_event *event; 3743 3744 if (!event_update_userpage(group_event)) 3745 return; 3746 3747 for_each_sibling_event(event, group_event) 3748 event_update_userpage(event); 3749 } 3750 3751 static int merge_sched_in(struct perf_event *event, void *data) 3752 { 3753 struct perf_event_context *ctx = event->ctx; 3754 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 3755 int *can_add_hw = data; 3756 3757 if (event->state <= PERF_EVENT_STATE_OFF) 3758 return 0; 3759 3760 if (!event_filter_match(event)) 3761 return 0; 3762 3763 if (group_can_go_on(event, cpuctx, *can_add_hw)) { 3764 if (!group_sched_in(event, cpuctx, ctx)) 3765 list_add_tail(&event->active_list, get_event_list(event)); 3766 } 3767 3768 if (event->state == PERF_EVENT_STATE_INACTIVE) { 3769 *can_add_hw = 0; 3770 if (event->attr.pinned) { 3771 perf_cgroup_event_disable(event, ctx); 3772 perf_event_set_state(event, PERF_EVENT_STATE_ERROR); 3773 } else { 3774 ctx->rotate_necessary = 1; 3775 perf_mux_hrtimer_restart(cpuctx); 3776 group_update_userpage(event); 3777 } 3778 } 3779 3780 return 0; 3781 } 3782 3783 static void 3784 ctx_pinned_sched_in(struct perf_event_context *ctx, 3785 struct perf_cpu_context *cpuctx) 3786 { 3787 int can_add_hw = 1; 3788 3789 if (ctx != &cpuctx->ctx) 3790 cpuctx = NULL; 3791 3792 visit_groups_merge(cpuctx, &ctx->pinned_groups, 3793 smp_processor_id(), 3794 merge_sched_in, &can_add_hw); 3795 } 3796 3797 static void 3798 ctx_flexible_sched_in(struct perf_event_context *ctx, 3799 struct perf_cpu_context *cpuctx) 3800 { 3801 int can_add_hw = 1; 3802 3803 if (ctx != &cpuctx->ctx) 3804 cpuctx = NULL; 3805 3806 visit_groups_merge(cpuctx, &ctx->flexible_groups, 3807 smp_processor_id(), 3808 merge_sched_in, &can_add_hw); 3809 } 3810 3811 static void 3812 ctx_sched_in(struct perf_event_context *ctx, 3813 struct perf_cpu_context *cpuctx, 3814 enum event_type_t event_type) 3815 { 3816 int is_active = ctx->is_active; 3817 3818 lockdep_assert_held(&ctx->lock); 3819 3820 if (likely(!ctx->nr_events)) 3821 return; 3822 3823 if (is_active ^ EVENT_TIME) { 3824 /* start ctx time */ 3825 __update_context_time(ctx, false); 3826 perf_cgroup_set_timestamp(cpuctx); 3827 /* 3828 * CPU-release for the below ->is_active store, 3829 * see __load_acquire() in perf_event_time_now() 3830 */ 3831 barrier(); 3832 } 3833 3834 ctx->is_active |= (event_type | EVENT_TIME); 3835 if (ctx->task) { 3836 if (!is_active) 3837 cpuctx->task_ctx = ctx; 3838 else 3839 WARN_ON_ONCE(cpuctx->task_ctx != ctx); 3840 } 3841 3842 is_active ^= ctx->is_active; /* changed bits */ 3843 3844 /* 3845 * First go through the list and put on any pinned groups 3846 * in order to give them the best chance of going on. 3847 */ 3848 if (is_active & EVENT_PINNED) 3849 ctx_pinned_sched_in(ctx, cpuctx); 3850 3851 /* Then walk through the lower prio flexible groups */ 3852 if (is_active & EVENT_FLEXIBLE) 3853 ctx_flexible_sched_in(ctx, cpuctx); 3854 } 3855 3856 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx, 3857 enum event_type_t event_type) 3858 { 3859 struct perf_event_context *ctx = &cpuctx->ctx; 3860 3861 ctx_sched_in(ctx, cpuctx, event_type); 3862 } 3863 3864 static void perf_event_context_sched_in(struct perf_event_context *ctx, 3865 struct task_struct *task) 3866 { 3867 struct perf_cpu_context *cpuctx; 3868 struct pmu *pmu; 3869 3870 cpuctx = __get_cpu_context(ctx); 3871 3872 /* 3873 * HACK: for HETEROGENEOUS the task context might have switched to a 3874 * different PMU, force (re)set the context, 3875 */ 3876 pmu = ctx->pmu = cpuctx->ctx.pmu; 3877 3878 if (cpuctx->task_ctx == ctx) { 3879 if (cpuctx->sched_cb_usage) 3880 __perf_pmu_sched_task(cpuctx, true); 3881 return; 3882 } 3883 3884 perf_ctx_lock(cpuctx, ctx); 3885 /* 3886 * We must check ctx->nr_events while holding ctx->lock, such 3887 * that we serialize against perf_install_in_context(). 3888 */ 3889 if (!ctx->nr_events) 3890 goto unlock; 3891 3892 perf_pmu_disable(pmu); 3893 /* 3894 * We want to keep the following priority order: 3895 * cpu pinned (that don't need to move), task pinned, 3896 * cpu flexible, task flexible. 3897 * 3898 * However, if task's ctx is not carrying any pinned 3899 * events, no need to flip the cpuctx's events around. 3900 */ 3901 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree)) 3902 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); 3903 perf_event_sched_in(cpuctx, ctx); 3904 3905 if (cpuctx->sched_cb_usage && pmu->sched_task) 3906 pmu->sched_task(cpuctx->task_ctx, true); 3907 3908 perf_pmu_enable(pmu); 3909 3910 unlock: 3911 perf_ctx_unlock(cpuctx, ctx); 3912 } 3913 3914 /* 3915 * Called from scheduler to add the events of the current task 3916 * with interrupts disabled. 3917 * 3918 * We restore the event value and then enable it. 3919 * 3920 * This does not protect us against NMI, but enable() 3921 * sets the enabled bit in the control field of event _before_ 3922 * accessing the event control register. If a NMI hits, then it will 3923 * keep the event running. 3924 */ 3925 void __perf_event_task_sched_in(struct task_struct *prev, 3926 struct task_struct *task) 3927 { 3928 struct perf_event_context *ctx; 3929 int ctxn; 3930 3931 for_each_task_context_nr(ctxn) { 3932 ctx = task->perf_event_ctxp[ctxn]; 3933 if (likely(!ctx)) 3934 continue; 3935 3936 perf_event_context_sched_in(ctx, task); 3937 } 3938 3939 if (atomic_read(&nr_switch_events)) 3940 perf_event_switch(task, prev, true); 3941 3942 if (__this_cpu_read(perf_sched_cb_usages)) 3943 perf_pmu_sched_task(prev, task, true); 3944 } 3945 3946 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count) 3947 { 3948 u64 frequency = event->attr.sample_freq; 3949 u64 sec = NSEC_PER_SEC; 3950 u64 divisor, dividend; 3951 3952 int count_fls, nsec_fls, frequency_fls, sec_fls; 3953 3954 count_fls = fls64(count); 3955 nsec_fls = fls64(nsec); 3956 frequency_fls = fls64(frequency); 3957 sec_fls = 30; 3958 3959 /* 3960 * We got @count in @nsec, with a target of sample_freq HZ 3961 * the target period becomes: 3962 * 3963 * @count * 10^9 3964 * period = ------------------- 3965 * @nsec * sample_freq 3966 * 3967 */ 3968 3969 /* 3970 * Reduce accuracy by one bit such that @a and @b converge 3971 * to a similar magnitude. 3972 */ 3973 #define REDUCE_FLS(a, b) \ 3974 do { \ 3975 if (a##_fls > b##_fls) { \ 3976 a >>= 1; \ 3977 a##_fls--; \ 3978 } else { \ 3979 b >>= 1; \ 3980 b##_fls--; \ 3981 } \ 3982 } while (0) 3983 3984 /* 3985 * Reduce accuracy until either term fits in a u64, then proceed with 3986 * the other, so that finally we can do a u64/u64 division. 3987 */ 3988 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) { 3989 REDUCE_FLS(nsec, frequency); 3990 REDUCE_FLS(sec, count); 3991 } 3992 3993 if (count_fls + sec_fls > 64) { 3994 divisor = nsec * frequency; 3995 3996 while (count_fls + sec_fls > 64) { 3997 REDUCE_FLS(count, sec); 3998 divisor >>= 1; 3999 } 4000 4001 dividend = count * sec; 4002 } else { 4003 dividend = count * sec; 4004 4005 while (nsec_fls + frequency_fls > 64) { 4006 REDUCE_FLS(nsec, frequency); 4007 dividend >>= 1; 4008 } 4009 4010 divisor = nsec * frequency; 4011 } 4012 4013 if (!divisor) 4014 return dividend; 4015 4016 return div64_u64(dividend, divisor); 4017 } 4018 4019 static DEFINE_PER_CPU(int, perf_throttled_count); 4020 static DEFINE_PER_CPU(u64, perf_throttled_seq); 4021 4022 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable) 4023 { 4024 struct hw_perf_event *hwc = &event->hw; 4025 s64 period, sample_period; 4026 s64 delta; 4027 4028 period = perf_calculate_period(event, nsec, count); 4029 4030 delta = (s64)(period - hwc->sample_period); 4031 delta = (delta + 7) / 8; /* low pass filter */ 4032 4033 sample_period = hwc->sample_period + delta; 4034 4035 if (!sample_period) 4036 sample_period = 1; 4037 4038 hwc->sample_period = sample_period; 4039 4040 if (local64_read(&hwc->period_left) > 8*sample_period) { 4041 if (disable) 4042 event->pmu->stop(event, PERF_EF_UPDATE); 4043 4044 local64_set(&hwc->period_left, 0); 4045 4046 if (disable) 4047 event->pmu->start(event, PERF_EF_RELOAD); 4048 } 4049 } 4050 4051 /* 4052 * combine freq adjustment with unthrottling to avoid two passes over the 4053 * events. At the same time, make sure, having freq events does not change 4054 * the rate of unthrottling as that would introduce bias. 4055 */ 4056 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx, 4057 int needs_unthr) 4058 { 4059 struct perf_event *event; 4060 struct hw_perf_event *hwc; 4061 u64 now, period = TICK_NSEC; 4062 s64 delta; 4063 4064 /* 4065 * only need to iterate over all events iff: 4066 * - context have events in frequency mode (needs freq adjust) 4067 * - there are events to unthrottle on this cpu 4068 */ 4069 if (!(ctx->nr_freq || needs_unthr)) 4070 return; 4071 4072 raw_spin_lock(&ctx->lock); 4073 perf_pmu_disable(ctx->pmu); 4074 4075 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 4076 if (event->state != PERF_EVENT_STATE_ACTIVE) 4077 continue; 4078 4079 if (!event_filter_match(event)) 4080 continue; 4081 4082 perf_pmu_disable(event->pmu); 4083 4084 hwc = &event->hw; 4085 4086 if (hwc->interrupts == MAX_INTERRUPTS) { 4087 hwc->interrupts = 0; 4088 perf_log_throttle(event, 1); 4089 event->pmu->start(event, 0); 4090 } 4091 4092 if (!event->attr.freq || !event->attr.sample_freq) 4093 goto next; 4094 4095 /* 4096 * stop the event and update event->count 4097 */ 4098 event->pmu->stop(event, PERF_EF_UPDATE); 4099 4100 now = local64_read(&event->count); 4101 delta = now - hwc->freq_count_stamp; 4102 hwc->freq_count_stamp = now; 4103 4104 /* 4105 * restart the event 4106 * reload only if value has changed 4107 * we have stopped the event so tell that 4108 * to perf_adjust_period() to avoid stopping it 4109 * twice. 4110 */ 4111 if (delta > 0) 4112 perf_adjust_period(event, period, delta, false); 4113 4114 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0); 4115 next: 4116 perf_pmu_enable(event->pmu); 4117 } 4118 4119 perf_pmu_enable(ctx->pmu); 4120 raw_spin_unlock(&ctx->lock); 4121 } 4122 4123 /* 4124 * Move @event to the tail of the @ctx's elegible events. 4125 */ 4126 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event) 4127 { 4128 /* 4129 * Rotate the first entry last of non-pinned groups. Rotation might be 4130 * disabled by the inheritance code. 4131 */ 4132 if (ctx->rotate_disable) 4133 return; 4134 4135 perf_event_groups_delete(&ctx->flexible_groups, event); 4136 perf_event_groups_insert(&ctx->flexible_groups, event); 4137 } 4138 4139 /* pick an event from the flexible_groups to rotate */ 4140 static inline struct perf_event * 4141 ctx_event_to_rotate(struct perf_event_context *ctx) 4142 { 4143 struct perf_event *event; 4144 4145 /* pick the first active flexible event */ 4146 event = list_first_entry_or_null(&ctx->flexible_active, 4147 struct perf_event, active_list); 4148 4149 /* if no active flexible event, pick the first event */ 4150 if (!event) { 4151 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree), 4152 typeof(*event), group_node); 4153 } 4154 4155 /* 4156 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in() 4157 * finds there are unschedulable events, it will set it again. 4158 */ 4159 ctx->rotate_necessary = 0; 4160 4161 return event; 4162 } 4163 4164 static bool perf_rotate_context(struct perf_cpu_context *cpuctx) 4165 { 4166 struct perf_event *cpu_event = NULL, *task_event = NULL; 4167 struct perf_event_context *task_ctx = NULL; 4168 int cpu_rotate, task_rotate; 4169 4170 /* 4171 * Since we run this from IRQ context, nobody can install new 4172 * events, thus the event count values are stable. 4173 */ 4174 4175 cpu_rotate = cpuctx->ctx.rotate_necessary; 4176 task_ctx = cpuctx->task_ctx; 4177 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0; 4178 4179 if (!(cpu_rotate || task_rotate)) 4180 return false; 4181 4182 perf_ctx_lock(cpuctx, cpuctx->task_ctx); 4183 perf_pmu_disable(cpuctx->ctx.pmu); 4184 4185 if (task_rotate) 4186 task_event = ctx_event_to_rotate(task_ctx); 4187 if (cpu_rotate) 4188 cpu_event = ctx_event_to_rotate(&cpuctx->ctx); 4189 4190 /* 4191 * As per the order given at ctx_resched() first 'pop' task flexible 4192 * and then, if needed CPU flexible. 4193 */ 4194 if (task_event || (task_ctx && cpu_event)) 4195 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE); 4196 if (cpu_event) 4197 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); 4198 4199 if (task_event) 4200 rotate_ctx(task_ctx, task_event); 4201 if (cpu_event) 4202 rotate_ctx(&cpuctx->ctx, cpu_event); 4203 4204 perf_event_sched_in(cpuctx, task_ctx); 4205 4206 perf_pmu_enable(cpuctx->ctx.pmu); 4207 perf_ctx_unlock(cpuctx, cpuctx->task_ctx); 4208 4209 return true; 4210 } 4211 4212 void perf_event_task_tick(void) 4213 { 4214 struct list_head *head = this_cpu_ptr(&active_ctx_list); 4215 struct perf_event_context *ctx, *tmp; 4216 int throttled; 4217 4218 lockdep_assert_irqs_disabled(); 4219 4220 __this_cpu_inc(perf_throttled_seq); 4221 throttled = __this_cpu_xchg(perf_throttled_count, 0); 4222 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); 4223 4224 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list) 4225 perf_adjust_freq_unthr_context(ctx, throttled); 4226 } 4227 4228 static int event_enable_on_exec(struct perf_event *event, 4229 struct perf_event_context *ctx) 4230 { 4231 if (!event->attr.enable_on_exec) 4232 return 0; 4233 4234 event->attr.enable_on_exec = 0; 4235 if (event->state >= PERF_EVENT_STATE_INACTIVE) 4236 return 0; 4237 4238 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE); 4239 4240 return 1; 4241 } 4242 4243 /* 4244 * Enable all of a task's events that have been marked enable-on-exec. 4245 * This expects task == current. 4246 */ 4247 static void perf_event_enable_on_exec(int ctxn) 4248 { 4249 struct perf_event_context *ctx, *clone_ctx = NULL; 4250 enum event_type_t event_type = 0; 4251 struct perf_cpu_context *cpuctx; 4252 struct perf_event *event; 4253 unsigned long flags; 4254 int enabled = 0; 4255 4256 local_irq_save(flags); 4257 ctx = current->perf_event_ctxp[ctxn]; 4258 if (!ctx || !ctx->nr_events) 4259 goto out; 4260 4261 cpuctx = __get_cpu_context(ctx); 4262 perf_ctx_lock(cpuctx, ctx); 4263 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 4264 list_for_each_entry(event, &ctx->event_list, event_entry) { 4265 enabled |= event_enable_on_exec(event, ctx); 4266 event_type |= get_event_type(event); 4267 } 4268 4269 /* 4270 * Unclone and reschedule this context if we enabled any event. 4271 */ 4272 if (enabled) { 4273 clone_ctx = unclone_ctx(ctx); 4274 ctx_resched(cpuctx, ctx, event_type); 4275 } else { 4276 ctx_sched_in(ctx, cpuctx, EVENT_TIME); 4277 } 4278 perf_ctx_unlock(cpuctx, ctx); 4279 4280 out: 4281 local_irq_restore(flags); 4282 4283 if (clone_ctx) 4284 put_ctx(clone_ctx); 4285 } 4286 4287 static void perf_remove_from_owner(struct perf_event *event); 4288 static void perf_event_exit_event(struct perf_event *event, 4289 struct perf_event_context *ctx); 4290 4291 /* 4292 * Removes all events from the current task that have been marked 4293 * remove-on-exec, and feeds their values back to parent events. 4294 */ 4295 static void perf_event_remove_on_exec(int ctxn) 4296 { 4297 struct perf_event_context *ctx, *clone_ctx = NULL; 4298 struct perf_event *event, *next; 4299 unsigned long flags; 4300 bool modified = false; 4301 4302 ctx = perf_pin_task_context(current, ctxn); 4303 if (!ctx) 4304 return; 4305 4306 mutex_lock(&ctx->mutex); 4307 4308 if (WARN_ON_ONCE(ctx->task != current)) 4309 goto unlock; 4310 4311 list_for_each_entry_safe(event, next, &ctx->event_list, event_entry) { 4312 if (!event->attr.remove_on_exec) 4313 continue; 4314 4315 if (!is_kernel_event(event)) 4316 perf_remove_from_owner(event); 4317 4318 modified = true; 4319 4320 perf_event_exit_event(event, ctx); 4321 } 4322 4323 raw_spin_lock_irqsave(&ctx->lock, flags); 4324 if (modified) 4325 clone_ctx = unclone_ctx(ctx); 4326 --ctx->pin_count; 4327 raw_spin_unlock_irqrestore(&ctx->lock, flags); 4328 4329 unlock: 4330 mutex_unlock(&ctx->mutex); 4331 4332 put_ctx(ctx); 4333 if (clone_ctx) 4334 put_ctx(clone_ctx); 4335 } 4336 4337 struct perf_read_data { 4338 struct perf_event *event; 4339 bool group; 4340 int ret; 4341 }; 4342 4343 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu) 4344 { 4345 u16 local_pkg, event_pkg; 4346 4347 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) { 4348 int local_cpu = smp_processor_id(); 4349 4350 event_pkg = topology_physical_package_id(event_cpu); 4351 local_pkg = topology_physical_package_id(local_cpu); 4352 4353 if (event_pkg == local_pkg) 4354 return local_cpu; 4355 } 4356 4357 return event_cpu; 4358 } 4359 4360 /* 4361 * Cross CPU call to read the hardware event 4362 */ 4363 static void __perf_event_read(void *info) 4364 { 4365 struct perf_read_data *data = info; 4366 struct perf_event *sub, *event = data->event; 4367 struct perf_event_context *ctx = event->ctx; 4368 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 4369 struct pmu *pmu = event->pmu; 4370 4371 /* 4372 * If this is a task context, we need to check whether it is 4373 * the current task context of this cpu. If not it has been 4374 * scheduled out before the smp call arrived. In that case 4375 * event->count would have been updated to a recent sample 4376 * when the event was scheduled out. 4377 */ 4378 if (ctx->task && cpuctx->task_ctx != ctx) 4379 return; 4380 4381 raw_spin_lock(&ctx->lock); 4382 if (ctx->is_active & EVENT_TIME) { 4383 update_context_time(ctx); 4384 update_cgrp_time_from_event(event); 4385 } 4386 4387 perf_event_update_time(event); 4388 if (data->group) 4389 perf_event_update_sibling_time(event); 4390 4391 if (event->state != PERF_EVENT_STATE_ACTIVE) 4392 goto unlock; 4393 4394 if (!data->group) { 4395 pmu->read(event); 4396 data->ret = 0; 4397 goto unlock; 4398 } 4399 4400 pmu->start_txn(pmu, PERF_PMU_TXN_READ); 4401 4402 pmu->read(event); 4403 4404 for_each_sibling_event(sub, event) { 4405 if (sub->state == PERF_EVENT_STATE_ACTIVE) { 4406 /* 4407 * Use sibling's PMU rather than @event's since 4408 * sibling could be on different (eg: software) PMU. 4409 */ 4410 sub->pmu->read(sub); 4411 } 4412 } 4413 4414 data->ret = pmu->commit_txn(pmu); 4415 4416 unlock: 4417 raw_spin_unlock(&ctx->lock); 4418 } 4419 4420 static inline u64 perf_event_count(struct perf_event *event) 4421 { 4422 return local64_read(&event->count) + atomic64_read(&event->child_count); 4423 } 4424 4425 static void calc_timer_values(struct perf_event *event, 4426 u64 *now, 4427 u64 *enabled, 4428 u64 *running) 4429 { 4430 u64 ctx_time; 4431 4432 *now = perf_clock(); 4433 ctx_time = perf_event_time_now(event, *now); 4434 __perf_update_times(event, ctx_time, enabled, running); 4435 } 4436 4437 /* 4438 * NMI-safe method to read a local event, that is an event that 4439 * is: 4440 * - either for the current task, or for this CPU 4441 * - does not have inherit set, for inherited task events 4442 * will not be local and we cannot read them atomically 4443 * - must not have a pmu::count method 4444 */ 4445 int perf_event_read_local(struct perf_event *event, u64 *value, 4446 u64 *enabled, u64 *running) 4447 { 4448 unsigned long flags; 4449 int ret = 0; 4450 4451 /* 4452 * Disabling interrupts avoids all counter scheduling (context 4453 * switches, timer based rotation and IPIs). 4454 */ 4455 local_irq_save(flags); 4456 4457 /* 4458 * It must not be an event with inherit set, we cannot read 4459 * all child counters from atomic context. 4460 */ 4461 if (event->attr.inherit) { 4462 ret = -EOPNOTSUPP; 4463 goto out; 4464 } 4465 4466 /* If this is a per-task event, it must be for current */ 4467 if ((event->attach_state & PERF_ATTACH_TASK) && 4468 event->hw.target != current) { 4469 ret = -EINVAL; 4470 goto out; 4471 } 4472 4473 /* If this is a per-CPU event, it must be for this CPU */ 4474 if (!(event->attach_state & PERF_ATTACH_TASK) && 4475 event->cpu != smp_processor_id()) { 4476 ret = -EINVAL; 4477 goto out; 4478 } 4479 4480 /* If this is a pinned event it must be running on this CPU */ 4481 if (event->attr.pinned && event->oncpu != smp_processor_id()) { 4482 ret = -EBUSY; 4483 goto out; 4484 } 4485 4486 /* 4487 * If the event is currently on this CPU, its either a per-task event, 4488 * or local to this CPU. Furthermore it means its ACTIVE (otherwise 4489 * oncpu == -1). 4490 */ 4491 if (event->oncpu == smp_processor_id()) 4492 event->pmu->read(event); 4493 4494 *value = local64_read(&event->count); 4495 if (enabled || running) { 4496 u64 __enabled, __running, __now; 4497 4498 calc_timer_values(event, &__now, &__enabled, &__running); 4499 if (enabled) 4500 *enabled = __enabled; 4501 if (running) 4502 *running = __running; 4503 } 4504 out: 4505 local_irq_restore(flags); 4506 4507 return ret; 4508 } 4509 4510 static int perf_event_read(struct perf_event *event, bool group) 4511 { 4512 enum perf_event_state state = READ_ONCE(event->state); 4513 int event_cpu, ret = 0; 4514 4515 /* 4516 * If event is enabled and currently active on a CPU, update the 4517 * value in the event structure: 4518 */ 4519 again: 4520 if (state == PERF_EVENT_STATE_ACTIVE) { 4521 struct perf_read_data data; 4522 4523 /* 4524 * Orders the ->state and ->oncpu loads such that if we see 4525 * ACTIVE we must also see the right ->oncpu. 4526 * 4527 * Matches the smp_wmb() from event_sched_in(). 4528 */ 4529 smp_rmb(); 4530 4531 event_cpu = READ_ONCE(event->oncpu); 4532 if ((unsigned)event_cpu >= nr_cpu_ids) 4533 return 0; 4534 4535 data = (struct perf_read_data){ 4536 .event = event, 4537 .group = group, 4538 .ret = 0, 4539 }; 4540 4541 preempt_disable(); 4542 event_cpu = __perf_event_read_cpu(event, event_cpu); 4543 4544 /* 4545 * Purposely ignore the smp_call_function_single() return 4546 * value. 4547 * 4548 * If event_cpu isn't a valid CPU it means the event got 4549 * scheduled out and that will have updated the event count. 4550 * 4551 * Therefore, either way, we'll have an up-to-date event count 4552 * after this. 4553 */ 4554 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1); 4555 preempt_enable(); 4556 ret = data.ret; 4557 4558 } else if (state == PERF_EVENT_STATE_INACTIVE) { 4559 struct perf_event_context *ctx = event->ctx; 4560 unsigned long flags; 4561 4562 raw_spin_lock_irqsave(&ctx->lock, flags); 4563 state = event->state; 4564 if (state != PERF_EVENT_STATE_INACTIVE) { 4565 raw_spin_unlock_irqrestore(&ctx->lock, flags); 4566 goto again; 4567 } 4568 4569 /* 4570 * May read while context is not active (e.g., thread is 4571 * blocked), in that case we cannot update context time 4572 */ 4573 if (ctx->is_active & EVENT_TIME) { 4574 update_context_time(ctx); 4575 update_cgrp_time_from_event(event); 4576 } 4577 4578 perf_event_update_time(event); 4579 if (group) 4580 perf_event_update_sibling_time(event); 4581 raw_spin_unlock_irqrestore(&ctx->lock, flags); 4582 } 4583 4584 return ret; 4585 } 4586 4587 /* 4588 * Initialize the perf_event context in a task_struct: 4589 */ 4590 static void __perf_event_init_context(struct perf_event_context *ctx) 4591 { 4592 raw_spin_lock_init(&ctx->lock); 4593 mutex_init(&ctx->mutex); 4594 INIT_LIST_HEAD(&ctx->active_ctx_list); 4595 perf_event_groups_init(&ctx->pinned_groups); 4596 perf_event_groups_init(&ctx->flexible_groups); 4597 INIT_LIST_HEAD(&ctx->event_list); 4598 INIT_LIST_HEAD(&ctx->pinned_active); 4599 INIT_LIST_HEAD(&ctx->flexible_active); 4600 refcount_set(&ctx->refcount, 1); 4601 } 4602 4603 static struct perf_event_context * 4604 alloc_perf_context(struct pmu *pmu, struct task_struct *task) 4605 { 4606 struct perf_event_context *ctx; 4607 4608 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL); 4609 if (!ctx) 4610 return NULL; 4611 4612 __perf_event_init_context(ctx); 4613 if (task) 4614 ctx->task = get_task_struct(task); 4615 ctx->pmu = pmu; 4616 4617 return ctx; 4618 } 4619 4620 static struct task_struct * 4621 find_lively_task_by_vpid(pid_t vpid) 4622 { 4623 struct task_struct *task; 4624 4625 rcu_read_lock(); 4626 if (!vpid) 4627 task = current; 4628 else 4629 task = find_task_by_vpid(vpid); 4630 if (task) 4631 get_task_struct(task); 4632 rcu_read_unlock(); 4633 4634 if (!task) 4635 return ERR_PTR(-ESRCH); 4636 4637 return task; 4638 } 4639 4640 /* 4641 * Returns a matching context with refcount and pincount. 4642 */ 4643 static struct perf_event_context * 4644 find_get_context(struct pmu *pmu, struct task_struct *task, 4645 struct perf_event *event) 4646 { 4647 struct perf_event_context *ctx, *clone_ctx = NULL; 4648 struct perf_cpu_context *cpuctx; 4649 void *task_ctx_data = NULL; 4650 unsigned long flags; 4651 int ctxn, err; 4652 int cpu = event->cpu; 4653 4654 if (!task) { 4655 /* Must be root to operate on a CPU event: */ 4656 err = perf_allow_cpu(&event->attr); 4657 if (err) 4658 return ERR_PTR(err); 4659 4660 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 4661 ctx = &cpuctx->ctx; 4662 get_ctx(ctx); 4663 raw_spin_lock_irqsave(&ctx->lock, flags); 4664 ++ctx->pin_count; 4665 raw_spin_unlock_irqrestore(&ctx->lock, flags); 4666 4667 return ctx; 4668 } 4669 4670 err = -EINVAL; 4671 ctxn = pmu->task_ctx_nr; 4672 if (ctxn < 0) 4673 goto errout; 4674 4675 if (event->attach_state & PERF_ATTACH_TASK_DATA) { 4676 task_ctx_data = alloc_task_ctx_data(pmu); 4677 if (!task_ctx_data) { 4678 err = -ENOMEM; 4679 goto errout; 4680 } 4681 } 4682 4683 retry: 4684 ctx = perf_lock_task_context(task, ctxn, &flags); 4685 if (ctx) { 4686 clone_ctx = unclone_ctx(ctx); 4687 ++ctx->pin_count; 4688 4689 if (task_ctx_data && !ctx->task_ctx_data) { 4690 ctx->task_ctx_data = task_ctx_data; 4691 task_ctx_data = NULL; 4692 } 4693 raw_spin_unlock_irqrestore(&ctx->lock, flags); 4694 4695 if (clone_ctx) 4696 put_ctx(clone_ctx); 4697 } else { 4698 ctx = alloc_perf_context(pmu, task); 4699 err = -ENOMEM; 4700 if (!ctx) 4701 goto errout; 4702 4703 if (task_ctx_data) { 4704 ctx->task_ctx_data = task_ctx_data; 4705 task_ctx_data = NULL; 4706 } 4707 4708 err = 0; 4709 mutex_lock(&task->perf_event_mutex); 4710 /* 4711 * If it has already passed perf_event_exit_task(). 4712 * we must see PF_EXITING, it takes this mutex too. 4713 */ 4714 if (task->flags & PF_EXITING) 4715 err = -ESRCH; 4716 else if (task->perf_event_ctxp[ctxn]) 4717 err = -EAGAIN; 4718 else { 4719 get_ctx(ctx); 4720 ++ctx->pin_count; 4721 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx); 4722 } 4723 mutex_unlock(&task->perf_event_mutex); 4724 4725 if (unlikely(err)) { 4726 put_ctx(ctx); 4727 4728 if (err == -EAGAIN) 4729 goto retry; 4730 goto errout; 4731 } 4732 } 4733 4734 free_task_ctx_data(pmu, task_ctx_data); 4735 return ctx; 4736 4737 errout: 4738 free_task_ctx_data(pmu, task_ctx_data); 4739 return ERR_PTR(err); 4740 } 4741 4742 static void perf_event_free_filter(struct perf_event *event); 4743 4744 static void free_event_rcu(struct rcu_head *head) 4745 { 4746 struct perf_event *event; 4747 4748 event = container_of(head, struct perf_event, rcu_head); 4749 if (event->ns) 4750 put_pid_ns(event->ns); 4751 perf_event_free_filter(event); 4752 kmem_cache_free(perf_event_cache, event); 4753 } 4754 4755 static void ring_buffer_attach(struct perf_event *event, 4756 struct perf_buffer *rb); 4757 4758 static void detach_sb_event(struct perf_event *event) 4759 { 4760 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu); 4761 4762 raw_spin_lock(&pel->lock); 4763 list_del_rcu(&event->sb_list); 4764 raw_spin_unlock(&pel->lock); 4765 } 4766 4767 static bool is_sb_event(struct perf_event *event) 4768 { 4769 struct perf_event_attr *attr = &event->attr; 4770 4771 if (event->parent) 4772 return false; 4773 4774 if (event->attach_state & PERF_ATTACH_TASK) 4775 return false; 4776 4777 if (attr->mmap || attr->mmap_data || attr->mmap2 || 4778 attr->comm || attr->comm_exec || 4779 attr->task || attr->ksymbol || 4780 attr->context_switch || attr->text_poke || 4781 attr->bpf_event) 4782 return true; 4783 return false; 4784 } 4785 4786 static void unaccount_pmu_sb_event(struct perf_event *event) 4787 { 4788 if (is_sb_event(event)) 4789 detach_sb_event(event); 4790 } 4791 4792 static void unaccount_event_cpu(struct perf_event *event, int cpu) 4793 { 4794 if (event->parent) 4795 return; 4796 4797 if (is_cgroup_event(event)) 4798 atomic_dec(&per_cpu(perf_cgroup_events, cpu)); 4799 } 4800 4801 #ifdef CONFIG_NO_HZ_FULL 4802 static DEFINE_SPINLOCK(nr_freq_lock); 4803 #endif 4804 4805 static void unaccount_freq_event_nohz(void) 4806 { 4807 #ifdef CONFIG_NO_HZ_FULL 4808 spin_lock(&nr_freq_lock); 4809 if (atomic_dec_and_test(&nr_freq_events)) 4810 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS); 4811 spin_unlock(&nr_freq_lock); 4812 #endif 4813 } 4814 4815 static void unaccount_freq_event(void) 4816 { 4817 if (tick_nohz_full_enabled()) 4818 unaccount_freq_event_nohz(); 4819 else 4820 atomic_dec(&nr_freq_events); 4821 } 4822 4823 static void unaccount_event(struct perf_event *event) 4824 { 4825 bool dec = false; 4826 4827 if (event->parent) 4828 return; 4829 4830 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB)) 4831 dec = true; 4832 if (event->attr.mmap || event->attr.mmap_data) 4833 atomic_dec(&nr_mmap_events); 4834 if (event->attr.build_id) 4835 atomic_dec(&nr_build_id_events); 4836 if (event->attr.comm) 4837 atomic_dec(&nr_comm_events); 4838 if (event->attr.namespaces) 4839 atomic_dec(&nr_namespaces_events); 4840 if (event->attr.cgroup) 4841 atomic_dec(&nr_cgroup_events); 4842 if (event->attr.task) 4843 atomic_dec(&nr_task_events); 4844 if (event->attr.freq) 4845 unaccount_freq_event(); 4846 if (event->attr.context_switch) { 4847 dec = true; 4848 atomic_dec(&nr_switch_events); 4849 } 4850 if (is_cgroup_event(event)) 4851 dec = true; 4852 if (has_branch_stack(event)) 4853 dec = true; 4854 if (event->attr.ksymbol) 4855 atomic_dec(&nr_ksymbol_events); 4856 if (event->attr.bpf_event) 4857 atomic_dec(&nr_bpf_events); 4858 if (event->attr.text_poke) 4859 atomic_dec(&nr_text_poke_events); 4860 4861 if (dec) { 4862 if (!atomic_add_unless(&perf_sched_count, -1, 1)) 4863 schedule_delayed_work(&perf_sched_work, HZ); 4864 } 4865 4866 unaccount_event_cpu(event, event->cpu); 4867 4868 unaccount_pmu_sb_event(event); 4869 } 4870 4871 static void perf_sched_delayed(struct work_struct *work) 4872 { 4873 mutex_lock(&perf_sched_mutex); 4874 if (atomic_dec_and_test(&perf_sched_count)) 4875 static_branch_disable(&perf_sched_events); 4876 mutex_unlock(&perf_sched_mutex); 4877 } 4878 4879 /* 4880 * The following implement mutual exclusion of events on "exclusive" pmus 4881 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled 4882 * at a time, so we disallow creating events that might conflict, namely: 4883 * 4884 * 1) cpu-wide events in the presence of per-task events, 4885 * 2) per-task events in the presence of cpu-wide events, 4886 * 3) two matching events on the same context. 4887 * 4888 * The former two cases are handled in the allocation path (perf_event_alloc(), 4889 * _free_event()), the latter -- before the first perf_install_in_context(). 4890 */ 4891 static int exclusive_event_init(struct perf_event *event) 4892 { 4893 struct pmu *pmu = event->pmu; 4894 4895 if (!is_exclusive_pmu(pmu)) 4896 return 0; 4897 4898 /* 4899 * Prevent co-existence of per-task and cpu-wide events on the 4900 * same exclusive pmu. 4901 * 4902 * Negative pmu::exclusive_cnt means there are cpu-wide 4903 * events on this "exclusive" pmu, positive means there are 4904 * per-task events. 4905 * 4906 * Since this is called in perf_event_alloc() path, event::ctx 4907 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK 4908 * to mean "per-task event", because unlike other attach states it 4909 * never gets cleared. 4910 */ 4911 if (event->attach_state & PERF_ATTACH_TASK) { 4912 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt)) 4913 return -EBUSY; 4914 } else { 4915 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt)) 4916 return -EBUSY; 4917 } 4918 4919 return 0; 4920 } 4921 4922 static void exclusive_event_destroy(struct perf_event *event) 4923 { 4924 struct pmu *pmu = event->pmu; 4925 4926 if (!is_exclusive_pmu(pmu)) 4927 return; 4928 4929 /* see comment in exclusive_event_init() */ 4930 if (event->attach_state & PERF_ATTACH_TASK) 4931 atomic_dec(&pmu->exclusive_cnt); 4932 else 4933 atomic_inc(&pmu->exclusive_cnt); 4934 } 4935 4936 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2) 4937 { 4938 if ((e1->pmu == e2->pmu) && 4939 (e1->cpu == e2->cpu || 4940 e1->cpu == -1 || 4941 e2->cpu == -1)) 4942 return true; 4943 return false; 4944 } 4945 4946 static bool exclusive_event_installable(struct perf_event *event, 4947 struct perf_event_context *ctx) 4948 { 4949 struct perf_event *iter_event; 4950 struct pmu *pmu = event->pmu; 4951 4952 lockdep_assert_held(&ctx->mutex); 4953 4954 if (!is_exclusive_pmu(pmu)) 4955 return true; 4956 4957 list_for_each_entry(iter_event, &ctx->event_list, event_entry) { 4958 if (exclusive_event_match(iter_event, event)) 4959 return false; 4960 } 4961 4962 return true; 4963 } 4964 4965 static void perf_addr_filters_splice(struct perf_event *event, 4966 struct list_head *head); 4967 4968 static void _free_event(struct perf_event *event) 4969 { 4970 irq_work_sync(&event->pending_irq); 4971 4972 unaccount_event(event); 4973 4974 security_perf_event_free(event); 4975 4976 if (event->rb) { 4977 /* 4978 * Can happen when we close an event with re-directed output. 4979 * 4980 * Since we have a 0 refcount, perf_mmap_close() will skip 4981 * over us; possibly making our ring_buffer_put() the last. 4982 */ 4983 mutex_lock(&event->mmap_mutex); 4984 ring_buffer_attach(event, NULL); 4985 mutex_unlock(&event->mmap_mutex); 4986 } 4987 4988 if (is_cgroup_event(event)) 4989 perf_detach_cgroup(event); 4990 4991 if (!event->parent) { 4992 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) 4993 put_callchain_buffers(); 4994 } 4995 4996 perf_event_free_bpf_prog(event); 4997 perf_addr_filters_splice(event, NULL); 4998 kfree(event->addr_filter_ranges); 4999 5000 if (event->destroy) 5001 event->destroy(event); 5002 5003 /* 5004 * Must be after ->destroy(), due to uprobe_perf_close() using 5005 * hw.target. 5006 */ 5007 if (event->hw.target) 5008 put_task_struct(event->hw.target); 5009 5010 /* 5011 * perf_event_free_task() relies on put_ctx() being 'last', in particular 5012 * all task references must be cleaned up. 5013 */ 5014 if (event->ctx) 5015 put_ctx(event->ctx); 5016 5017 exclusive_event_destroy(event); 5018 module_put(event->pmu->module); 5019 5020 call_rcu(&event->rcu_head, free_event_rcu); 5021 } 5022 5023 /* 5024 * Used to free events which have a known refcount of 1, such as in error paths 5025 * where the event isn't exposed yet and inherited events. 5026 */ 5027 static void free_event(struct perf_event *event) 5028 { 5029 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1, 5030 "unexpected event refcount: %ld; ptr=%p\n", 5031 atomic_long_read(&event->refcount), event)) { 5032 /* leak to avoid use-after-free */ 5033 return; 5034 } 5035 5036 _free_event(event); 5037 } 5038 5039 /* 5040 * Remove user event from the owner task. 5041 */ 5042 static void perf_remove_from_owner(struct perf_event *event) 5043 { 5044 struct task_struct *owner; 5045 5046 rcu_read_lock(); 5047 /* 5048 * Matches the smp_store_release() in perf_event_exit_task(). If we 5049 * observe !owner it means the list deletion is complete and we can 5050 * indeed free this event, otherwise we need to serialize on 5051 * owner->perf_event_mutex. 5052 */ 5053 owner = READ_ONCE(event->owner); 5054 if (owner) { 5055 /* 5056 * Since delayed_put_task_struct() also drops the last 5057 * task reference we can safely take a new reference 5058 * while holding the rcu_read_lock(). 5059 */ 5060 get_task_struct(owner); 5061 } 5062 rcu_read_unlock(); 5063 5064 if (owner) { 5065 /* 5066 * If we're here through perf_event_exit_task() we're already 5067 * holding ctx->mutex which would be an inversion wrt. the 5068 * normal lock order. 5069 * 5070 * However we can safely take this lock because its the child 5071 * ctx->mutex. 5072 */ 5073 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING); 5074 5075 /* 5076 * We have to re-check the event->owner field, if it is cleared 5077 * we raced with perf_event_exit_task(), acquiring the mutex 5078 * ensured they're done, and we can proceed with freeing the 5079 * event. 5080 */ 5081 if (event->owner) { 5082 list_del_init(&event->owner_entry); 5083 smp_store_release(&event->owner, NULL); 5084 } 5085 mutex_unlock(&owner->perf_event_mutex); 5086 put_task_struct(owner); 5087 } 5088 } 5089 5090 static void put_event(struct perf_event *event) 5091 { 5092 if (!atomic_long_dec_and_test(&event->refcount)) 5093 return; 5094 5095 _free_event(event); 5096 } 5097 5098 /* 5099 * Kill an event dead; while event:refcount will preserve the event 5100 * object, it will not preserve its functionality. Once the last 'user' 5101 * gives up the object, we'll destroy the thing. 5102 */ 5103 int perf_event_release_kernel(struct perf_event *event) 5104 { 5105 struct perf_event_context *ctx = event->ctx; 5106 struct perf_event *child, *tmp; 5107 LIST_HEAD(free_list); 5108 5109 /* 5110 * If we got here through err_file: fput(event_file); we will not have 5111 * attached to a context yet. 5112 */ 5113 if (!ctx) { 5114 WARN_ON_ONCE(event->attach_state & 5115 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP)); 5116 goto no_ctx; 5117 } 5118 5119 if (!is_kernel_event(event)) 5120 perf_remove_from_owner(event); 5121 5122 ctx = perf_event_ctx_lock(event); 5123 WARN_ON_ONCE(ctx->parent_ctx); 5124 perf_remove_from_context(event, DETACH_GROUP); 5125 5126 raw_spin_lock_irq(&ctx->lock); 5127 /* 5128 * Mark this event as STATE_DEAD, there is no external reference to it 5129 * anymore. 5130 * 5131 * Anybody acquiring event->child_mutex after the below loop _must_ 5132 * also see this, most importantly inherit_event() which will avoid 5133 * placing more children on the list. 5134 * 5135 * Thus this guarantees that we will in fact observe and kill _ALL_ 5136 * child events. 5137 */ 5138 event->state = PERF_EVENT_STATE_DEAD; 5139 raw_spin_unlock_irq(&ctx->lock); 5140 5141 perf_event_ctx_unlock(event, ctx); 5142 5143 again: 5144 mutex_lock(&event->child_mutex); 5145 list_for_each_entry(child, &event->child_list, child_list) { 5146 5147 /* 5148 * Cannot change, child events are not migrated, see the 5149 * comment with perf_event_ctx_lock_nested(). 5150 */ 5151 ctx = READ_ONCE(child->ctx); 5152 /* 5153 * Since child_mutex nests inside ctx::mutex, we must jump 5154 * through hoops. We start by grabbing a reference on the ctx. 5155 * 5156 * Since the event cannot get freed while we hold the 5157 * child_mutex, the context must also exist and have a !0 5158 * reference count. 5159 */ 5160 get_ctx(ctx); 5161 5162 /* 5163 * Now that we have a ctx ref, we can drop child_mutex, and 5164 * acquire ctx::mutex without fear of it going away. Then we 5165 * can re-acquire child_mutex. 5166 */ 5167 mutex_unlock(&event->child_mutex); 5168 mutex_lock(&ctx->mutex); 5169 mutex_lock(&event->child_mutex); 5170 5171 /* 5172 * Now that we hold ctx::mutex and child_mutex, revalidate our 5173 * state, if child is still the first entry, it didn't get freed 5174 * and we can continue doing so. 5175 */ 5176 tmp = list_first_entry_or_null(&event->child_list, 5177 struct perf_event, child_list); 5178 if (tmp == child) { 5179 perf_remove_from_context(child, DETACH_GROUP); 5180 list_move(&child->child_list, &free_list); 5181 /* 5182 * This matches the refcount bump in inherit_event(); 5183 * this can't be the last reference. 5184 */ 5185 put_event(event); 5186 } 5187 5188 mutex_unlock(&event->child_mutex); 5189 mutex_unlock(&ctx->mutex); 5190 put_ctx(ctx); 5191 goto again; 5192 } 5193 mutex_unlock(&event->child_mutex); 5194 5195 list_for_each_entry_safe(child, tmp, &free_list, child_list) { 5196 void *var = &child->ctx->refcount; 5197 5198 list_del(&child->child_list); 5199 free_event(child); 5200 5201 /* 5202 * Wake any perf_event_free_task() waiting for this event to be 5203 * freed. 5204 */ 5205 smp_mb(); /* pairs with wait_var_event() */ 5206 wake_up_var(var); 5207 } 5208 5209 no_ctx: 5210 put_event(event); /* Must be the 'last' reference */ 5211 return 0; 5212 } 5213 EXPORT_SYMBOL_GPL(perf_event_release_kernel); 5214 5215 /* 5216 * Called when the last reference to the file is gone. 5217 */ 5218 static int perf_release(struct inode *inode, struct file *file) 5219 { 5220 perf_event_release_kernel(file->private_data); 5221 return 0; 5222 } 5223 5224 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) 5225 { 5226 struct perf_event *child; 5227 u64 total = 0; 5228 5229 *enabled = 0; 5230 *running = 0; 5231 5232 mutex_lock(&event->child_mutex); 5233 5234 (void)perf_event_read(event, false); 5235 total += perf_event_count(event); 5236 5237 *enabled += event->total_time_enabled + 5238 atomic64_read(&event->child_total_time_enabled); 5239 *running += event->total_time_running + 5240 atomic64_read(&event->child_total_time_running); 5241 5242 list_for_each_entry(child, &event->child_list, child_list) { 5243 (void)perf_event_read(child, false); 5244 total += perf_event_count(child); 5245 *enabled += child->total_time_enabled; 5246 *running += child->total_time_running; 5247 } 5248 mutex_unlock(&event->child_mutex); 5249 5250 return total; 5251 } 5252 5253 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running) 5254 { 5255 struct perf_event_context *ctx; 5256 u64 count; 5257 5258 ctx = perf_event_ctx_lock(event); 5259 count = __perf_event_read_value(event, enabled, running); 5260 perf_event_ctx_unlock(event, ctx); 5261 5262 return count; 5263 } 5264 EXPORT_SYMBOL_GPL(perf_event_read_value); 5265 5266 static int __perf_read_group_add(struct perf_event *leader, 5267 u64 read_format, u64 *values) 5268 { 5269 struct perf_event_context *ctx = leader->ctx; 5270 struct perf_event *sub; 5271 unsigned long flags; 5272 int n = 1; /* skip @nr */ 5273 int ret; 5274 5275 ret = perf_event_read(leader, true); 5276 if (ret) 5277 return ret; 5278 5279 raw_spin_lock_irqsave(&ctx->lock, flags); 5280 5281 /* 5282 * Since we co-schedule groups, {enabled,running} times of siblings 5283 * will be identical to those of the leader, so we only publish one 5284 * set. 5285 */ 5286 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { 5287 values[n++] += leader->total_time_enabled + 5288 atomic64_read(&leader->child_total_time_enabled); 5289 } 5290 5291 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { 5292 values[n++] += leader->total_time_running + 5293 atomic64_read(&leader->child_total_time_running); 5294 } 5295 5296 /* 5297 * Write {count,id} tuples for every sibling. 5298 */ 5299 values[n++] += perf_event_count(leader); 5300 if (read_format & PERF_FORMAT_ID) 5301 values[n++] = primary_event_id(leader); 5302 if (read_format & PERF_FORMAT_LOST) 5303 values[n++] = atomic64_read(&leader->lost_samples); 5304 5305 for_each_sibling_event(sub, leader) { 5306 values[n++] += perf_event_count(sub); 5307 if (read_format & PERF_FORMAT_ID) 5308 values[n++] = primary_event_id(sub); 5309 if (read_format & PERF_FORMAT_LOST) 5310 values[n++] = atomic64_read(&sub->lost_samples); 5311 } 5312 5313 raw_spin_unlock_irqrestore(&ctx->lock, flags); 5314 return 0; 5315 } 5316 5317 static int perf_read_group(struct perf_event *event, 5318 u64 read_format, char __user *buf) 5319 { 5320 struct perf_event *leader = event->group_leader, *child; 5321 struct perf_event_context *ctx = leader->ctx; 5322 int ret; 5323 u64 *values; 5324 5325 lockdep_assert_held(&ctx->mutex); 5326 5327 values = kzalloc(event->read_size, GFP_KERNEL); 5328 if (!values) 5329 return -ENOMEM; 5330 5331 values[0] = 1 + leader->nr_siblings; 5332 5333 /* 5334 * By locking the child_mutex of the leader we effectively 5335 * lock the child list of all siblings.. XXX explain how. 5336 */ 5337 mutex_lock(&leader->child_mutex); 5338 5339 ret = __perf_read_group_add(leader, read_format, values); 5340 if (ret) 5341 goto unlock; 5342 5343 list_for_each_entry(child, &leader->child_list, child_list) { 5344 ret = __perf_read_group_add(child, read_format, values); 5345 if (ret) 5346 goto unlock; 5347 } 5348 5349 mutex_unlock(&leader->child_mutex); 5350 5351 ret = event->read_size; 5352 if (copy_to_user(buf, values, event->read_size)) 5353 ret = -EFAULT; 5354 goto out; 5355 5356 unlock: 5357 mutex_unlock(&leader->child_mutex); 5358 out: 5359 kfree(values); 5360 return ret; 5361 } 5362 5363 static int perf_read_one(struct perf_event *event, 5364 u64 read_format, char __user *buf) 5365 { 5366 u64 enabled, running; 5367 u64 values[5]; 5368 int n = 0; 5369 5370 values[n++] = __perf_event_read_value(event, &enabled, &running); 5371 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 5372 values[n++] = enabled; 5373 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 5374 values[n++] = running; 5375 if (read_format & PERF_FORMAT_ID) 5376 values[n++] = primary_event_id(event); 5377 if (read_format & PERF_FORMAT_LOST) 5378 values[n++] = atomic64_read(&event->lost_samples); 5379 5380 if (copy_to_user(buf, values, n * sizeof(u64))) 5381 return -EFAULT; 5382 5383 return n * sizeof(u64); 5384 } 5385 5386 static bool is_event_hup(struct perf_event *event) 5387 { 5388 bool no_children; 5389 5390 if (event->state > PERF_EVENT_STATE_EXIT) 5391 return false; 5392 5393 mutex_lock(&event->child_mutex); 5394 no_children = list_empty(&event->child_list); 5395 mutex_unlock(&event->child_mutex); 5396 return no_children; 5397 } 5398 5399 /* 5400 * Read the performance event - simple non blocking version for now 5401 */ 5402 static ssize_t 5403 __perf_read(struct perf_event *event, char __user *buf, size_t count) 5404 { 5405 u64 read_format = event->attr.read_format; 5406 int ret; 5407 5408 /* 5409 * Return end-of-file for a read on an event that is in 5410 * error state (i.e. because it was pinned but it couldn't be 5411 * scheduled on to the CPU at some point). 5412 */ 5413 if (event->state == PERF_EVENT_STATE_ERROR) 5414 return 0; 5415 5416 if (count < event->read_size) 5417 return -ENOSPC; 5418 5419 WARN_ON_ONCE(event->ctx->parent_ctx); 5420 if (read_format & PERF_FORMAT_GROUP) 5421 ret = perf_read_group(event, read_format, buf); 5422 else 5423 ret = perf_read_one(event, read_format, buf); 5424 5425 return ret; 5426 } 5427 5428 static ssize_t 5429 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 5430 { 5431 struct perf_event *event = file->private_data; 5432 struct perf_event_context *ctx; 5433 int ret; 5434 5435 ret = security_perf_event_read(event); 5436 if (ret) 5437 return ret; 5438 5439 ctx = perf_event_ctx_lock(event); 5440 ret = __perf_read(event, buf, count); 5441 perf_event_ctx_unlock(event, ctx); 5442 5443 return ret; 5444 } 5445 5446 static __poll_t perf_poll(struct file *file, poll_table *wait) 5447 { 5448 struct perf_event *event = file->private_data; 5449 struct perf_buffer *rb; 5450 __poll_t events = EPOLLHUP; 5451 5452 poll_wait(file, &event->waitq, wait); 5453 5454 if (is_event_hup(event)) 5455 return events; 5456 5457 /* 5458 * Pin the event->rb by taking event->mmap_mutex; otherwise 5459 * perf_event_set_output() can swizzle our rb and make us miss wakeups. 5460 */ 5461 mutex_lock(&event->mmap_mutex); 5462 rb = event->rb; 5463 if (rb) 5464 events = atomic_xchg(&rb->poll, 0); 5465 mutex_unlock(&event->mmap_mutex); 5466 return events; 5467 } 5468 5469 static void _perf_event_reset(struct perf_event *event) 5470 { 5471 (void)perf_event_read(event, false); 5472 local64_set(&event->count, 0); 5473 perf_event_update_userpage(event); 5474 } 5475 5476 /* Assume it's not an event with inherit set. */ 5477 u64 perf_event_pause(struct perf_event *event, bool reset) 5478 { 5479 struct perf_event_context *ctx; 5480 u64 count; 5481 5482 ctx = perf_event_ctx_lock(event); 5483 WARN_ON_ONCE(event->attr.inherit); 5484 _perf_event_disable(event); 5485 count = local64_read(&event->count); 5486 if (reset) 5487 local64_set(&event->count, 0); 5488 perf_event_ctx_unlock(event, ctx); 5489 5490 return count; 5491 } 5492 EXPORT_SYMBOL_GPL(perf_event_pause); 5493 5494 /* 5495 * Holding the top-level event's child_mutex means that any 5496 * descendant process that has inherited this event will block 5497 * in perf_event_exit_event() if it goes to exit, thus satisfying the 5498 * task existence requirements of perf_event_enable/disable. 5499 */ 5500 static void perf_event_for_each_child(struct perf_event *event, 5501 void (*func)(struct perf_event *)) 5502 { 5503 struct perf_event *child; 5504 5505 WARN_ON_ONCE(event->ctx->parent_ctx); 5506 5507 mutex_lock(&event->child_mutex); 5508 func(event); 5509 list_for_each_entry(child, &event->child_list, child_list) 5510 func(child); 5511 mutex_unlock(&event->child_mutex); 5512 } 5513 5514 static void perf_event_for_each(struct perf_event *event, 5515 void (*func)(struct perf_event *)) 5516 { 5517 struct perf_event_context *ctx = event->ctx; 5518 struct perf_event *sibling; 5519 5520 lockdep_assert_held(&ctx->mutex); 5521 5522 event = event->group_leader; 5523 5524 perf_event_for_each_child(event, func); 5525 for_each_sibling_event(sibling, event) 5526 perf_event_for_each_child(sibling, func); 5527 } 5528 5529 static void __perf_event_period(struct perf_event *event, 5530 struct perf_cpu_context *cpuctx, 5531 struct perf_event_context *ctx, 5532 void *info) 5533 { 5534 u64 value = *((u64 *)info); 5535 bool active; 5536 5537 if (event->attr.freq) { 5538 event->attr.sample_freq = value; 5539 } else { 5540 event->attr.sample_period = value; 5541 event->hw.sample_period = value; 5542 } 5543 5544 active = (event->state == PERF_EVENT_STATE_ACTIVE); 5545 if (active) { 5546 perf_pmu_disable(ctx->pmu); 5547 /* 5548 * We could be throttled; unthrottle now to avoid the tick 5549 * trying to unthrottle while we already re-started the event. 5550 */ 5551 if (event->hw.interrupts == MAX_INTERRUPTS) { 5552 event->hw.interrupts = 0; 5553 perf_log_throttle(event, 1); 5554 } 5555 event->pmu->stop(event, PERF_EF_UPDATE); 5556 } 5557 5558 local64_set(&event->hw.period_left, 0); 5559 5560 if (active) { 5561 event->pmu->start(event, PERF_EF_RELOAD); 5562 perf_pmu_enable(ctx->pmu); 5563 } 5564 } 5565 5566 static int perf_event_check_period(struct perf_event *event, u64 value) 5567 { 5568 return event->pmu->check_period(event, value); 5569 } 5570 5571 static int _perf_event_period(struct perf_event *event, u64 value) 5572 { 5573 if (!is_sampling_event(event)) 5574 return -EINVAL; 5575 5576 if (!value) 5577 return -EINVAL; 5578 5579 if (event->attr.freq && value > sysctl_perf_event_sample_rate) 5580 return -EINVAL; 5581 5582 if (perf_event_check_period(event, value)) 5583 return -EINVAL; 5584 5585 if (!event->attr.freq && (value & (1ULL << 63))) 5586 return -EINVAL; 5587 5588 event_function_call(event, __perf_event_period, &value); 5589 5590 return 0; 5591 } 5592 5593 int perf_event_period(struct perf_event *event, u64 value) 5594 { 5595 struct perf_event_context *ctx; 5596 int ret; 5597 5598 ctx = perf_event_ctx_lock(event); 5599 ret = _perf_event_period(event, value); 5600 perf_event_ctx_unlock(event, ctx); 5601 5602 return ret; 5603 } 5604 EXPORT_SYMBOL_GPL(perf_event_period); 5605 5606 static const struct file_operations perf_fops; 5607 5608 static inline int perf_fget_light(int fd, struct fd *p) 5609 { 5610 struct fd f = fdget(fd); 5611 if (!f.file) 5612 return -EBADF; 5613 5614 if (f.file->f_op != &perf_fops) { 5615 fdput(f); 5616 return -EBADF; 5617 } 5618 *p = f; 5619 return 0; 5620 } 5621 5622 static int perf_event_set_output(struct perf_event *event, 5623 struct perf_event *output_event); 5624 static int perf_event_set_filter(struct perf_event *event, void __user *arg); 5625 static int perf_copy_attr(struct perf_event_attr __user *uattr, 5626 struct perf_event_attr *attr); 5627 5628 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg) 5629 { 5630 void (*func)(struct perf_event *); 5631 u32 flags = arg; 5632 5633 switch (cmd) { 5634 case PERF_EVENT_IOC_ENABLE: 5635 func = _perf_event_enable; 5636 break; 5637 case PERF_EVENT_IOC_DISABLE: 5638 func = _perf_event_disable; 5639 break; 5640 case PERF_EVENT_IOC_RESET: 5641 func = _perf_event_reset; 5642 break; 5643 5644 case PERF_EVENT_IOC_REFRESH: 5645 return _perf_event_refresh(event, arg); 5646 5647 case PERF_EVENT_IOC_PERIOD: 5648 { 5649 u64 value; 5650 5651 if (copy_from_user(&value, (u64 __user *)arg, sizeof(value))) 5652 return -EFAULT; 5653 5654 return _perf_event_period(event, value); 5655 } 5656 case PERF_EVENT_IOC_ID: 5657 { 5658 u64 id = primary_event_id(event); 5659 5660 if (copy_to_user((void __user *)arg, &id, sizeof(id))) 5661 return -EFAULT; 5662 return 0; 5663 } 5664 5665 case PERF_EVENT_IOC_SET_OUTPUT: 5666 { 5667 int ret; 5668 if (arg != -1) { 5669 struct perf_event *output_event; 5670 struct fd output; 5671 ret = perf_fget_light(arg, &output); 5672 if (ret) 5673 return ret; 5674 output_event = output.file->private_data; 5675 ret = perf_event_set_output(event, output_event); 5676 fdput(output); 5677 } else { 5678 ret = perf_event_set_output(event, NULL); 5679 } 5680 return ret; 5681 } 5682 5683 case PERF_EVENT_IOC_SET_FILTER: 5684 return perf_event_set_filter(event, (void __user *)arg); 5685 5686 case PERF_EVENT_IOC_SET_BPF: 5687 { 5688 struct bpf_prog *prog; 5689 int err; 5690 5691 prog = bpf_prog_get(arg); 5692 if (IS_ERR(prog)) 5693 return PTR_ERR(prog); 5694 5695 err = perf_event_set_bpf_prog(event, prog, 0); 5696 if (err) { 5697 bpf_prog_put(prog); 5698 return err; 5699 } 5700 5701 return 0; 5702 } 5703 5704 case PERF_EVENT_IOC_PAUSE_OUTPUT: { 5705 struct perf_buffer *rb; 5706 5707 rcu_read_lock(); 5708 rb = rcu_dereference(event->rb); 5709 if (!rb || !rb->nr_pages) { 5710 rcu_read_unlock(); 5711 return -EINVAL; 5712 } 5713 rb_toggle_paused(rb, !!arg); 5714 rcu_read_unlock(); 5715 return 0; 5716 } 5717 5718 case PERF_EVENT_IOC_QUERY_BPF: 5719 return perf_event_query_prog_array(event, (void __user *)arg); 5720 5721 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: { 5722 struct perf_event_attr new_attr; 5723 int err = perf_copy_attr((struct perf_event_attr __user *)arg, 5724 &new_attr); 5725 5726 if (err) 5727 return err; 5728 5729 return perf_event_modify_attr(event, &new_attr); 5730 } 5731 default: 5732 return -ENOTTY; 5733 } 5734 5735 if (flags & PERF_IOC_FLAG_GROUP) 5736 perf_event_for_each(event, func); 5737 else 5738 perf_event_for_each_child(event, func); 5739 5740 return 0; 5741 } 5742 5743 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 5744 { 5745 struct perf_event *event = file->private_data; 5746 struct perf_event_context *ctx; 5747 long ret; 5748 5749 /* Treat ioctl like writes as it is likely a mutating operation. */ 5750 ret = security_perf_event_write(event); 5751 if (ret) 5752 return ret; 5753 5754 ctx = perf_event_ctx_lock(event); 5755 ret = _perf_ioctl(event, cmd, arg); 5756 perf_event_ctx_unlock(event, ctx); 5757 5758 return ret; 5759 } 5760 5761 #ifdef CONFIG_COMPAT 5762 static long perf_compat_ioctl(struct file *file, unsigned int cmd, 5763 unsigned long arg) 5764 { 5765 switch (_IOC_NR(cmd)) { 5766 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER): 5767 case _IOC_NR(PERF_EVENT_IOC_ID): 5768 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF): 5769 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES): 5770 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */ 5771 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) { 5772 cmd &= ~IOCSIZE_MASK; 5773 cmd |= sizeof(void *) << IOCSIZE_SHIFT; 5774 } 5775 break; 5776 } 5777 return perf_ioctl(file, cmd, arg); 5778 } 5779 #else 5780 # define perf_compat_ioctl NULL 5781 #endif 5782 5783 int perf_event_task_enable(void) 5784 { 5785 struct perf_event_context *ctx; 5786 struct perf_event *event; 5787 5788 mutex_lock(¤t->perf_event_mutex); 5789 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { 5790 ctx = perf_event_ctx_lock(event); 5791 perf_event_for_each_child(event, _perf_event_enable); 5792 perf_event_ctx_unlock(event, ctx); 5793 } 5794 mutex_unlock(¤t->perf_event_mutex); 5795 5796 return 0; 5797 } 5798 5799 int perf_event_task_disable(void) 5800 { 5801 struct perf_event_context *ctx; 5802 struct perf_event *event; 5803 5804 mutex_lock(¤t->perf_event_mutex); 5805 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) { 5806 ctx = perf_event_ctx_lock(event); 5807 perf_event_for_each_child(event, _perf_event_disable); 5808 perf_event_ctx_unlock(event, ctx); 5809 } 5810 mutex_unlock(¤t->perf_event_mutex); 5811 5812 return 0; 5813 } 5814 5815 static int perf_event_index(struct perf_event *event) 5816 { 5817 if (event->hw.state & PERF_HES_STOPPED) 5818 return 0; 5819 5820 if (event->state != PERF_EVENT_STATE_ACTIVE) 5821 return 0; 5822 5823 return event->pmu->event_idx(event); 5824 } 5825 5826 static void perf_event_init_userpage(struct perf_event *event) 5827 { 5828 struct perf_event_mmap_page *userpg; 5829 struct perf_buffer *rb; 5830 5831 rcu_read_lock(); 5832 rb = rcu_dereference(event->rb); 5833 if (!rb) 5834 goto unlock; 5835 5836 userpg = rb->user_page; 5837 5838 /* Allow new userspace to detect that bit 0 is deprecated */ 5839 userpg->cap_bit0_is_deprecated = 1; 5840 userpg->size = offsetof(struct perf_event_mmap_page, __reserved); 5841 userpg->data_offset = PAGE_SIZE; 5842 userpg->data_size = perf_data_size(rb); 5843 5844 unlock: 5845 rcu_read_unlock(); 5846 } 5847 5848 void __weak arch_perf_update_userpage( 5849 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now) 5850 { 5851 } 5852 5853 /* 5854 * Callers need to ensure there can be no nesting of this function, otherwise 5855 * the seqlock logic goes bad. We can not serialize this because the arch 5856 * code calls this from NMI context. 5857 */ 5858 void perf_event_update_userpage(struct perf_event *event) 5859 { 5860 struct perf_event_mmap_page *userpg; 5861 struct perf_buffer *rb; 5862 u64 enabled, running, now; 5863 5864 rcu_read_lock(); 5865 rb = rcu_dereference(event->rb); 5866 if (!rb) 5867 goto unlock; 5868 5869 /* 5870 * compute total_time_enabled, total_time_running 5871 * based on snapshot values taken when the event 5872 * was last scheduled in. 5873 * 5874 * we cannot simply called update_context_time() 5875 * because of locking issue as we can be called in 5876 * NMI context 5877 */ 5878 calc_timer_values(event, &now, &enabled, &running); 5879 5880 userpg = rb->user_page; 5881 /* 5882 * Disable preemption to guarantee consistent time stamps are stored to 5883 * the user page. 5884 */ 5885 preempt_disable(); 5886 ++userpg->lock; 5887 barrier(); 5888 userpg->index = perf_event_index(event); 5889 userpg->offset = perf_event_count(event); 5890 if (userpg->index) 5891 userpg->offset -= local64_read(&event->hw.prev_count); 5892 5893 userpg->time_enabled = enabled + 5894 atomic64_read(&event->child_total_time_enabled); 5895 5896 userpg->time_running = running + 5897 atomic64_read(&event->child_total_time_running); 5898 5899 arch_perf_update_userpage(event, userpg, now); 5900 5901 barrier(); 5902 ++userpg->lock; 5903 preempt_enable(); 5904 unlock: 5905 rcu_read_unlock(); 5906 } 5907 EXPORT_SYMBOL_GPL(perf_event_update_userpage); 5908 5909 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf) 5910 { 5911 struct perf_event *event = vmf->vma->vm_file->private_data; 5912 struct perf_buffer *rb; 5913 vm_fault_t ret = VM_FAULT_SIGBUS; 5914 5915 if (vmf->flags & FAULT_FLAG_MKWRITE) { 5916 if (vmf->pgoff == 0) 5917 ret = 0; 5918 return ret; 5919 } 5920 5921 rcu_read_lock(); 5922 rb = rcu_dereference(event->rb); 5923 if (!rb) 5924 goto unlock; 5925 5926 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE)) 5927 goto unlock; 5928 5929 vmf->page = perf_mmap_to_page(rb, vmf->pgoff); 5930 if (!vmf->page) 5931 goto unlock; 5932 5933 get_page(vmf->page); 5934 vmf->page->mapping = vmf->vma->vm_file->f_mapping; 5935 vmf->page->index = vmf->pgoff; 5936 5937 ret = 0; 5938 unlock: 5939 rcu_read_unlock(); 5940 5941 return ret; 5942 } 5943 5944 static void ring_buffer_attach(struct perf_event *event, 5945 struct perf_buffer *rb) 5946 { 5947 struct perf_buffer *old_rb = NULL; 5948 unsigned long flags; 5949 5950 WARN_ON_ONCE(event->parent); 5951 5952 if (event->rb) { 5953 /* 5954 * Should be impossible, we set this when removing 5955 * event->rb_entry and wait/clear when adding event->rb_entry. 5956 */ 5957 WARN_ON_ONCE(event->rcu_pending); 5958 5959 old_rb = event->rb; 5960 spin_lock_irqsave(&old_rb->event_lock, flags); 5961 list_del_rcu(&event->rb_entry); 5962 spin_unlock_irqrestore(&old_rb->event_lock, flags); 5963 5964 event->rcu_batches = get_state_synchronize_rcu(); 5965 event->rcu_pending = 1; 5966 } 5967 5968 if (rb) { 5969 if (event->rcu_pending) { 5970 cond_synchronize_rcu(event->rcu_batches); 5971 event->rcu_pending = 0; 5972 } 5973 5974 spin_lock_irqsave(&rb->event_lock, flags); 5975 list_add_rcu(&event->rb_entry, &rb->event_list); 5976 spin_unlock_irqrestore(&rb->event_lock, flags); 5977 } 5978 5979 /* 5980 * Avoid racing with perf_mmap_close(AUX): stop the event 5981 * before swizzling the event::rb pointer; if it's getting 5982 * unmapped, its aux_mmap_count will be 0 and it won't 5983 * restart. See the comment in __perf_pmu_output_stop(). 5984 * 5985 * Data will inevitably be lost when set_output is done in 5986 * mid-air, but then again, whoever does it like this is 5987 * not in for the data anyway. 5988 */ 5989 if (has_aux(event)) 5990 perf_event_stop(event, 0); 5991 5992 rcu_assign_pointer(event->rb, rb); 5993 5994 if (old_rb) { 5995 ring_buffer_put(old_rb); 5996 /* 5997 * Since we detached before setting the new rb, so that we 5998 * could attach the new rb, we could have missed a wakeup. 5999 * Provide it now. 6000 */ 6001 wake_up_all(&event->waitq); 6002 } 6003 } 6004 6005 static void ring_buffer_wakeup(struct perf_event *event) 6006 { 6007 struct perf_buffer *rb; 6008 6009 if (event->parent) 6010 event = event->parent; 6011 6012 rcu_read_lock(); 6013 rb = rcu_dereference(event->rb); 6014 if (rb) { 6015 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) 6016 wake_up_all(&event->waitq); 6017 } 6018 rcu_read_unlock(); 6019 } 6020 6021 struct perf_buffer *ring_buffer_get(struct perf_event *event) 6022 { 6023 struct perf_buffer *rb; 6024 6025 if (event->parent) 6026 event = event->parent; 6027 6028 rcu_read_lock(); 6029 rb = rcu_dereference(event->rb); 6030 if (rb) { 6031 if (!refcount_inc_not_zero(&rb->refcount)) 6032 rb = NULL; 6033 } 6034 rcu_read_unlock(); 6035 6036 return rb; 6037 } 6038 6039 void ring_buffer_put(struct perf_buffer *rb) 6040 { 6041 if (!refcount_dec_and_test(&rb->refcount)) 6042 return; 6043 6044 WARN_ON_ONCE(!list_empty(&rb->event_list)); 6045 6046 call_rcu(&rb->rcu_head, rb_free_rcu); 6047 } 6048 6049 static void perf_mmap_open(struct vm_area_struct *vma) 6050 { 6051 struct perf_event *event = vma->vm_file->private_data; 6052 6053 atomic_inc(&event->mmap_count); 6054 atomic_inc(&event->rb->mmap_count); 6055 6056 if (vma->vm_pgoff) 6057 atomic_inc(&event->rb->aux_mmap_count); 6058 6059 if (event->pmu->event_mapped) 6060 event->pmu->event_mapped(event, vma->vm_mm); 6061 } 6062 6063 static void perf_pmu_output_stop(struct perf_event *event); 6064 6065 /* 6066 * A buffer can be mmap()ed multiple times; either directly through the same 6067 * event, or through other events by use of perf_event_set_output(). 6068 * 6069 * In order to undo the VM accounting done by perf_mmap() we need to destroy 6070 * the buffer here, where we still have a VM context. This means we need 6071 * to detach all events redirecting to us. 6072 */ 6073 static void perf_mmap_close(struct vm_area_struct *vma) 6074 { 6075 struct perf_event *event = vma->vm_file->private_data; 6076 struct perf_buffer *rb = ring_buffer_get(event); 6077 struct user_struct *mmap_user = rb->mmap_user; 6078 int mmap_locked = rb->mmap_locked; 6079 unsigned long size = perf_data_size(rb); 6080 bool detach_rest = false; 6081 6082 if (event->pmu->event_unmapped) 6083 event->pmu->event_unmapped(event, vma->vm_mm); 6084 6085 /* 6086 * rb->aux_mmap_count will always drop before rb->mmap_count and 6087 * event->mmap_count, so it is ok to use event->mmap_mutex to 6088 * serialize with perf_mmap here. 6089 */ 6090 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff && 6091 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) { 6092 /* 6093 * Stop all AUX events that are writing to this buffer, 6094 * so that we can free its AUX pages and corresponding PMU 6095 * data. Note that after rb::aux_mmap_count dropped to zero, 6096 * they won't start any more (see perf_aux_output_begin()). 6097 */ 6098 perf_pmu_output_stop(event); 6099 6100 /* now it's safe to free the pages */ 6101 atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm); 6102 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm); 6103 6104 /* this has to be the last one */ 6105 rb_free_aux(rb); 6106 WARN_ON_ONCE(refcount_read(&rb->aux_refcount)); 6107 6108 mutex_unlock(&event->mmap_mutex); 6109 } 6110 6111 if (atomic_dec_and_test(&rb->mmap_count)) 6112 detach_rest = true; 6113 6114 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) 6115 goto out_put; 6116 6117 ring_buffer_attach(event, NULL); 6118 mutex_unlock(&event->mmap_mutex); 6119 6120 /* If there's still other mmap()s of this buffer, we're done. */ 6121 if (!detach_rest) 6122 goto out_put; 6123 6124 /* 6125 * No other mmap()s, detach from all other events that might redirect 6126 * into the now unreachable buffer. Somewhat complicated by the 6127 * fact that rb::event_lock otherwise nests inside mmap_mutex. 6128 */ 6129 again: 6130 rcu_read_lock(); 6131 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) { 6132 if (!atomic_long_inc_not_zero(&event->refcount)) { 6133 /* 6134 * This event is en-route to free_event() which will 6135 * detach it and remove it from the list. 6136 */ 6137 continue; 6138 } 6139 rcu_read_unlock(); 6140 6141 mutex_lock(&event->mmap_mutex); 6142 /* 6143 * Check we didn't race with perf_event_set_output() which can 6144 * swizzle the rb from under us while we were waiting to 6145 * acquire mmap_mutex. 6146 * 6147 * If we find a different rb; ignore this event, a next 6148 * iteration will no longer find it on the list. We have to 6149 * still restart the iteration to make sure we're not now 6150 * iterating the wrong list. 6151 */ 6152 if (event->rb == rb) 6153 ring_buffer_attach(event, NULL); 6154 6155 mutex_unlock(&event->mmap_mutex); 6156 put_event(event); 6157 6158 /* 6159 * Restart the iteration; either we're on the wrong list or 6160 * destroyed its integrity by doing a deletion. 6161 */ 6162 goto again; 6163 } 6164 rcu_read_unlock(); 6165 6166 /* 6167 * It could be there's still a few 0-ref events on the list; they'll 6168 * get cleaned up by free_event() -- they'll also still have their 6169 * ref on the rb and will free it whenever they are done with it. 6170 * 6171 * Aside from that, this buffer is 'fully' detached and unmapped, 6172 * undo the VM accounting. 6173 */ 6174 6175 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked, 6176 &mmap_user->locked_vm); 6177 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm); 6178 free_uid(mmap_user); 6179 6180 out_put: 6181 ring_buffer_put(rb); /* could be last */ 6182 } 6183 6184 static const struct vm_operations_struct perf_mmap_vmops = { 6185 .open = perf_mmap_open, 6186 .close = perf_mmap_close, /* non mergeable */ 6187 .fault = perf_mmap_fault, 6188 .page_mkwrite = perf_mmap_fault, 6189 }; 6190 6191 static int perf_mmap(struct file *file, struct vm_area_struct *vma) 6192 { 6193 struct perf_event *event = file->private_data; 6194 unsigned long user_locked, user_lock_limit; 6195 struct user_struct *user = current_user(); 6196 struct perf_buffer *rb = NULL; 6197 unsigned long locked, lock_limit; 6198 unsigned long vma_size; 6199 unsigned long nr_pages; 6200 long user_extra = 0, extra = 0; 6201 int ret = 0, flags = 0; 6202 6203 /* 6204 * Don't allow mmap() of inherited per-task counters. This would 6205 * create a performance issue due to all children writing to the 6206 * same rb. 6207 */ 6208 if (event->cpu == -1 && event->attr.inherit) 6209 return -EINVAL; 6210 6211 if (!(vma->vm_flags & VM_SHARED)) 6212 return -EINVAL; 6213 6214 ret = security_perf_event_read(event); 6215 if (ret) 6216 return ret; 6217 6218 vma_size = vma->vm_end - vma->vm_start; 6219 6220 if (vma->vm_pgoff == 0) { 6221 nr_pages = (vma_size / PAGE_SIZE) - 1; 6222 } else { 6223 /* 6224 * AUX area mapping: if rb->aux_nr_pages != 0, it's already 6225 * mapped, all subsequent mappings should have the same size 6226 * and offset. Must be above the normal perf buffer. 6227 */ 6228 u64 aux_offset, aux_size; 6229 6230 if (!event->rb) 6231 return -EINVAL; 6232 6233 nr_pages = vma_size / PAGE_SIZE; 6234 6235 mutex_lock(&event->mmap_mutex); 6236 ret = -EINVAL; 6237 6238 rb = event->rb; 6239 if (!rb) 6240 goto aux_unlock; 6241 6242 aux_offset = READ_ONCE(rb->user_page->aux_offset); 6243 aux_size = READ_ONCE(rb->user_page->aux_size); 6244 6245 if (aux_offset < perf_data_size(rb) + PAGE_SIZE) 6246 goto aux_unlock; 6247 6248 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT) 6249 goto aux_unlock; 6250 6251 /* already mapped with a different offset */ 6252 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff) 6253 goto aux_unlock; 6254 6255 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE) 6256 goto aux_unlock; 6257 6258 /* already mapped with a different size */ 6259 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages) 6260 goto aux_unlock; 6261 6262 if (!is_power_of_2(nr_pages)) 6263 goto aux_unlock; 6264 6265 if (!atomic_inc_not_zero(&rb->mmap_count)) 6266 goto aux_unlock; 6267 6268 if (rb_has_aux(rb)) { 6269 atomic_inc(&rb->aux_mmap_count); 6270 ret = 0; 6271 goto unlock; 6272 } 6273 6274 atomic_set(&rb->aux_mmap_count, 1); 6275 user_extra = nr_pages; 6276 6277 goto accounting; 6278 } 6279 6280 /* 6281 * If we have rb pages ensure they're a power-of-two number, so we 6282 * can do bitmasks instead of modulo. 6283 */ 6284 if (nr_pages != 0 && !is_power_of_2(nr_pages)) 6285 return -EINVAL; 6286 6287 if (vma_size != PAGE_SIZE * (1 + nr_pages)) 6288 return -EINVAL; 6289 6290 WARN_ON_ONCE(event->ctx->parent_ctx); 6291 again: 6292 mutex_lock(&event->mmap_mutex); 6293 if (event->rb) { 6294 if (data_page_nr(event->rb) != nr_pages) { 6295 ret = -EINVAL; 6296 goto unlock; 6297 } 6298 6299 if (!atomic_inc_not_zero(&event->rb->mmap_count)) { 6300 /* 6301 * Raced against perf_mmap_close(); remove the 6302 * event and try again. 6303 */ 6304 ring_buffer_attach(event, NULL); 6305 mutex_unlock(&event->mmap_mutex); 6306 goto again; 6307 } 6308 6309 goto unlock; 6310 } 6311 6312 user_extra = nr_pages + 1; 6313 6314 accounting: 6315 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10); 6316 6317 /* 6318 * Increase the limit linearly with more CPUs: 6319 */ 6320 user_lock_limit *= num_online_cpus(); 6321 6322 user_locked = atomic_long_read(&user->locked_vm); 6323 6324 /* 6325 * sysctl_perf_event_mlock may have changed, so that 6326 * user->locked_vm > user_lock_limit 6327 */ 6328 if (user_locked > user_lock_limit) 6329 user_locked = user_lock_limit; 6330 user_locked += user_extra; 6331 6332 if (user_locked > user_lock_limit) { 6333 /* 6334 * charge locked_vm until it hits user_lock_limit; 6335 * charge the rest from pinned_vm 6336 */ 6337 extra = user_locked - user_lock_limit; 6338 user_extra -= extra; 6339 } 6340 6341 lock_limit = rlimit(RLIMIT_MEMLOCK); 6342 lock_limit >>= PAGE_SHIFT; 6343 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra; 6344 6345 if ((locked > lock_limit) && perf_is_paranoid() && 6346 !capable(CAP_IPC_LOCK)) { 6347 ret = -EPERM; 6348 goto unlock; 6349 } 6350 6351 WARN_ON(!rb && event->rb); 6352 6353 if (vma->vm_flags & VM_WRITE) 6354 flags |= RING_BUFFER_WRITABLE; 6355 6356 if (!rb) { 6357 rb = rb_alloc(nr_pages, 6358 event->attr.watermark ? event->attr.wakeup_watermark : 0, 6359 event->cpu, flags); 6360 6361 if (!rb) { 6362 ret = -ENOMEM; 6363 goto unlock; 6364 } 6365 6366 atomic_set(&rb->mmap_count, 1); 6367 rb->mmap_user = get_current_user(); 6368 rb->mmap_locked = extra; 6369 6370 ring_buffer_attach(event, rb); 6371 6372 perf_event_update_time(event); 6373 perf_event_init_userpage(event); 6374 perf_event_update_userpage(event); 6375 } else { 6376 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages, 6377 event->attr.aux_watermark, flags); 6378 if (!ret) 6379 rb->aux_mmap_locked = extra; 6380 } 6381 6382 unlock: 6383 if (!ret) { 6384 atomic_long_add(user_extra, &user->locked_vm); 6385 atomic64_add(extra, &vma->vm_mm->pinned_vm); 6386 6387 atomic_inc(&event->mmap_count); 6388 } else if (rb) { 6389 atomic_dec(&rb->mmap_count); 6390 } 6391 aux_unlock: 6392 mutex_unlock(&event->mmap_mutex); 6393 6394 /* 6395 * Since pinned accounting is per vm we cannot allow fork() to copy our 6396 * vma. 6397 */ 6398 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP; 6399 vma->vm_ops = &perf_mmap_vmops; 6400 6401 if (event->pmu->event_mapped) 6402 event->pmu->event_mapped(event, vma->vm_mm); 6403 6404 return ret; 6405 } 6406 6407 static int perf_fasync(int fd, struct file *filp, int on) 6408 { 6409 struct inode *inode = file_inode(filp); 6410 struct perf_event *event = filp->private_data; 6411 int retval; 6412 6413 inode_lock(inode); 6414 retval = fasync_helper(fd, filp, on, &event->fasync); 6415 inode_unlock(inode); 6416 6417 if (retval < 0) 6418 return retval; 6419 6420 return 0; 6421 } 6422 6423 static const struct file_operations perf_fops = { 6424 .llseek = no_llseek, 6425 .release = perf_release, 6426 .read = perf_read, 6427 .poll = perf_poll, 6428 .unlocked_ioctl = perf_ioctl, 6429 .compat_ioctl = perf_compat_ioctl, 6430 .mmap = perf_mmap, 6431 .fasync = perf_fasync, 6432 }; 6433 6434 /* 6435 * Perf event wakeup 6436 * 6437 * If there's data, ensure we set the poll() state and publish everything 6438 * to user-space before waking everybody up. 6439 */ 6440 6441 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event) 6442 { 6443 /* only the parent has fasync state */ 6444 if (event->parent) 6445 event = event->parent; 6446 return &event->fasync; 6447 } 6448 6449 void perf_event_wakeup(struct perf_event *event) 6450 { 6451 ring_buffer_wakeup(event); 6452 6453 if (event->pending_kill) { 6454 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill); 6455 event->pending_kill = 0; 6456 } 6457 } 6458 6459 static void perf_sigtrap(struct perf_event *event) 6460 { 6461 /* 6462 * We'd expect this to only occur if the irq_work is delayed and either 6463 * ctx->task or current has changed in the meantime. This can be the 6464 * case on architectures that do not implement arch_irq_work_raise(). 6465 */ 6466 if (WARN_ON_ONCE(event->ctx->task != current)) 6467 return; 6468 6469 /* 6470 * Both perf_pending_task() and perf_pending_irq() can race with the 6471 * task exiting. 6472 */ 6473 if (current->flags & PF_EXITING) 6474 return; 6475 6476 send_sig_perf((void __user *)event->pending_addr, 6477 event->attr.type, event->attr.sig_data); 6478 } 6479 6480 /* 6481 * Deliver the pending work in-event-context or follow the context. 6482 */ 6483 static void __perf_pending_irq(struct perf_event *event) 6484 { 6485 int cpu = READ_ONCE(event->oncpu); 6486 6487 /* 6488 * If the event isn't running; we done. event_sched_out() will have 6489 * taken care of things. 6490 */ 6491 if (cpu < 0) 6492 return; 6493 6494 /* 6495 * Yay, we hit home and are in the context of the event. 6496 */ 6497 if (cpu == smp_processor_id()) { 6498 if (event->pending_sigtrap) { 6499 event->pending_sigtrap = 0; 6500 perf_sigtrap(event); 6501 local_dec(&event->ctx->nr_pending); 6502 } 6503 if (event->pending_disable) { 6504 event->pending_disable = 0; 6505 perf_event_disable_local(event); 6506 } 6507 return; 6508 } 6509 6510 /* 6511 * CPU-A CPU-B 6512 * 6513 * perf_event_disable_inatomic() 6514 * @pending_disable = CPU-A; 6515 * irq_work_queue(); 6516 * 6517 * sched-out 6518 * @pending_disable = -1; 6519 * 6520 * sched-in 6521 * perf_event_disable_inatomic() 6522 * @pending_disable = CPU-B; 6523 * irq_work_queue(); // FAILS 6524 * 6525 * irq_work_run() 6526 * perf_pending_irq() 6527 * 6528 * But the event runs on CPU-B and wants disabling there. 6529 */ 6530 irq_work_queue_on(&event->pending_irq, cpu); 6531 } 6532 6533 static void perf_pending_irq(struct irq_work *entry) 6534 { 6535 struct perf_event *event = container_of(entry, struct perf_event, pending_irq); 6536 int rctx; 6537 6538 /* 6539 * If we 'fail' here, that's OK, it means recursion is already disabled 6540 * and we won't recurse 'further'. 6541 */ 6542 rctx = perf_swevent_get_recursion_context(); 6543 6544 /* 6545 * The wakeup isn't bound to the context of the event -- it can happen 6546 * irrespective of where the event is. 6547 */ 6548 if (event->pending_wakeup) { 6549 event->pending_wakeup = 0; 6550 perf_event_wakeup(event); 6551 } 6552 6553 __perf_pending_irq(event); 6554 6555 if (rctx >= 0) 6556 perf_swevent_put_recursion_context(rctx); 6557 } 6558 6559 static void perf_pending_task(struct callback_head *head) 6560 { 6561 struct perf_event *event = container_of(head, struct perf_event, pending_task); 6562 int rctx; 6563 6564 /* 6565 * If we 'fail' here, that's OK, it means recursion is already disabled 6566 * and we won't recurse 'further'. 6567 */ 6568 preempt_disable_notrace(); 6569 rctx = perf_swevent_get_recursion_context(); 6570 6571 if (event->pending_work) { 6572 event->pending_work = 0; 6573 perf_sigtrap(event); 6574 local_dec(&event->ctx->nr_pending); 6575 } 6576 6577 if (rctx >= 0) 6578 perf_swevent_put_recursion_context(rctx); 6579 preempt_enable_notrace(); 6580 } 6581 6582 #ifdef CONFIG_GUEST_PERF_EVENTS 6583 struct perf_guest_info_callbacks __rcu *perf_guest_cbs; 6584 6585 DEFINE_STATIC_CALL_RET0(__perf_guest_state, *perf_guest_cbs->state); 6586 DEFINE_STATIC_CALL_RET0(__perf_guest_get_ip, *perf_guest_cbs->get_ip); 6587 DEFINE_STATIC_CALL_RET0(__perf_guest_handle_intel_pt_intr, *perf_guest_cbs->handle_intel_pt_intr); 6588 6589 void perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) 6590 { 6591 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs))) 6592 return; 6593 6594 rcu_assign_pointer(perf_guest_cbs, cbs); 6595 static_call_update(__perf_guest_state, cbs->state); 6596 static_call_update(__perf_guest_get_ip, cbs->get_ip); 6597 6598 /* Implementing ->handle_intel_pt_intr is optional. */ 6599 if (cbs->handle_intel_pt_intr) 6600 static_call_update(__perf_guest_handle_intel_pt_intr, 6601 cbs->handle_intel_pt_intr); 6602 } 6603 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks); 6604 6605 void perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs) 6606 { 6607 if (WARN_ON_ONCE(rcu_access_pointer(perf_guest_cbs) != cbs)) 6608 return; 6609 6610 rcu_assign_pointer(perf_guest_cbs, NULL); 6611 static_call_update(__perf_guest_state, (void *)&__static_call_return0); 6612 static_call_update(__perf_guest_get_ip, (void *)&__static_call_return0); 6613 static_call_update(__perf_guest_handle_intel_pt_intr, 6614 (void *)&__static_call_return0); 6615 synchronize_rcu(); 6616 } 6617 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks); 6618 #endif 6619 6620 static void 6621 perf_output_sample_regs(struct perf_output_handle *handle, 6622 struct pt_regs *regs, u64 mask) 6623 { 6624 int bit; 6625 DECLARE_BITMAP(_mask, 64); 6626 6627 bitmap_from_u64(_mask, mask); 6628 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) { 6629 u64 val; 6630 6631 val = perf_reg_value(regs, bit); 6632 perf_output_put(handle, val); 6633 } 6634 } 6635 6636 static void perf_sample_regs_user(struct perf_regs *regs_user, 6637 struct pt_regs *regs) 6638 { 6639 if (user_mode(regs)) { 6640 regs_user->abi = perf_reg_abi(current); 6641 regs_user->regs = regs; 6642 } else if (!(current->flags & PF_KTHREAD)) { 6643 perf_get_regs_user(regs_user, regs); 6644 } else { 6645 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE; 6646 regs_user->regs = NULL; 6647 } 6648 } 6649 6650 static void perf_sample_regs_intr(struct perf_regs *regs_intr, 6651 struct pt_regs *regs) 6652 { 6653 regs_intr->regs = regs; 6654 regs_intr->abi = perf_reg_abi(current); 6655 } 6656 6657 6658 /* 6659 * Get remaining task size from user stack pointer. 6660 * 6661 * It'd be better to take stack vma map and limit this more 6662 * precisely, but there's no way to get it safely under interrupt, 6663 * so using TASK_SIZE as limit. 6664 */ 6665 static u64 perf_ustack_task_size(struct pt_regs *regs) 6666 { 6667 unsigned long addr = perf_user_stack_pointer(regs); 6668 6669 if (!addr || addr >= TASK_SIZE) 6670 return 0; 6671 6672 return TASK_SIZE - addr; 6673 } 6674 6675 static u16 6676 perf_sample_ustack_size(u16 stack_size, u16 header_size, 6677 struct pt_regs *regs) 6678 { 6679 u64 task_size; 6680 6681 /* No regs, no stack pointer, no dump. */ 6682 if (!regs) 6683 return 0; 6684 6685 /* 6686 * Check if we fit in with the requested stack size into the: 6687 * - TASK_SIZE 6688 * If we don't, we limit the size to the TASK_SIZE. 6689 * 6690 * - remaining sample size 6691 * If we don't, we customize the stack size to 6692 * fit in to the remaining sample size. 6693 */ 6694 6695 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs)); 6696 stack_size = min(stack_size, (u16) task_size); 6697 6698 /* Current header size plus static size and dynamic size. */ 6699 header_size += 2 * sizeof(u64); 6700 6701 /* Do we fit in with the current stack dump size? */ 6702 if ((u16) (header_size + stack_size) < header_size) { 6703 /* 6704 * If we overflow the maximum size for the sample, 6705 * we customize the stack dump size to fit in. 6706 */ 6707 stack_size = USHRT_MAX - header_size - sizeof(u64); 6708 stack_size = round_up(stack_size, sizeof(u64)); 6709 } 6710 6711 return stack_size; 6712 } 6713 6714 static void 6715 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size, 6716 struct pt_regs *regs) 6717 { 6718 /* Case of a kernel thread, nothing to dump */ 6719 if (!regs) { 6720 u64 size = 0; 6721 perf_output_put(handle, size); 6722 } else { 6723 unsigned long sp; 6724 unsigned int rem; 6725 u64 dyn_size; 6726 6727 /* 6728 * We dump: 6729 * static size 6730 * - the size requested by user or the best one we can fit 6731 * in to the sample max size 6732 * data 6733 * - user stack dump data 6734 * dynamic size 6735 * - the actual dumped size 6736 */ 6737 6738 /* Static size. */ 6739 perf_output_put(handle, dump_size); 6740 6741 /* Data. */ 6742 sp = perf_user_stack_pointer(regs); 6743 rem = __output_copy_user(handle, (void *) sp, dump_size); 6744 dyn_size = dump_size - rem; 6745 6746 perf_output_skip(handle, rem); 6747 6748 /* Dynamic size. */ 6749 perf_output_put(handle, dyn_size); 6750 } 6751 } 6752 6753 static unsigned long perf_prepare_sample_aux(struct perf_event *event, 6754 struct perf_sample_data *data, 6755 size_t size) 6756 { 6757 struct perf_event *sampler = event->aux_event; 6758 struct perf_buffer *rb; 6759 6760 data->aux_size = 0; 6761 6762 if (!sampler) 6763 goto out; 6764 6765 if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE)) 6766 goto out; 6767 6768 if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id())) 6769 goto out; 6770 6771 rb = ring_buffer_get(sampler); 6772 if (!rb) 6773 goto out; 6774 6775 /* 6776 * If this is an NMI hit inside sampling code, don't take 6777 * the sample. See also perf_aux_sample_output(). 6778 */ 6779 if (READ_ONCE(rb->aux_in_sampling)) { 6780 data->aux_size = 0; 6781 } else { 6782 size = min_t(size_t, size, perf_aux_size(rb)); 6783 data->aux_size = ALIGN(size, sizeof(u64)); 6784 } 6785 ring_buffer_put(rb); 6786 6787 out: 6788 return data->aux_size; 6789 } 6790 6791 static long perf_pmu_snapshot_aux(struct perf_buffer *rb, 6792 struct perf_event *event, 6793 struct perf_output_handle *handle, 6794 unsigned long size) 6795 { 6796 unsigned long flags; 6797 long ret; 6798 6799 /* 6800 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler 6801 * paths. If we start calling them in NMI context, they may race with 6802 * the IRQ ones, that is, for example, re-starting an event that's just 6803 * been stopped, which is why we're using a separate callback that 6804 * doesn't change the event state. 6805 * 6806 * IRQs need to be disabled to prevent IPIs from racing with us. 6807 */ 6808 local_irq_save(flags); 6809 /* 6810 * Guard against NMI hits inside the critical section; 6811 * see also perf_prepare_sample_aux(). 6812 */ 6813 WRITE_ONCE(rb->aux_in_sampling, 1); 6814 barrier(); 6815 6816 ret = event->pmu->snapshot_aux(event, handle, size); 6817 6818 barrier(); 6819 WRITE_ONCE(rb->aux_in_sampling, 0); 6820 local_irq_restore(flags); 6821 6822 return ret; 6823 } 6824 6825 static void perf_aux_sample_output(struct perf_event *event, 6826 struct perf_output_handle *handle, 6827 struct perf_sample_data *data) 6828 { 6829 struct perf_event *sampler = event->aux_event; 6830 struct perf_buffer *rb; 6831 unsigned long pad; 6832 long size; 6833 6834 if (WARN_ON_ONCE(!sampler || !data->aux_size)) 6835 return; 6836 6837 rb = ring_buffer_get(sampler); 6838 if (!rb) 6839 return; 6840 6841 size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size); 6842 6843 /* 6844 * An error here means that perf_output_copy() failed (returned a 6845 * non-zero surplus that it didn't copy), which in its current 6846 * enlightened implementation is not possible. If that changes, we'd 6847 * like to know. 6848 */ 6849 if (WARN_ON_ONCE(size < 0)) 6850 goto out_put; 6851 6852 /* 6853 * The pad comes from ALIGN()ing data->aux_size up to u64 in 6854 * perf_prepare_sample_aux(), so should not be more than that. 6855 */ 6856 pad = data->aux_size - size; 6857 if (WARN_ON_ONCE(pad >= sizeof(u64))) 6858 pad = 8; 6859 6860 if (pad) { 6861 u64 zero = 0; 6862 perf_output_copy(handle, &zero, pad); 6863 } 6864 6865 out_put: 6866 ring_buffer_put(rb); 6867 } 6868 6869 static void __perf_event_header__init_id(struct perf_event_header *header, 6870 struct perf_sample_data *data, 6871 struct perf_event *event, 6872 u64 sample_type) 6873 { 6874 data->type = event->attr.sample_type; 6875 header->size += event->id_header_size; 6876 6877 if (sample_type & PERF_SAMPLE_TID) { 6878 /* namespace issues */ 6879 data->tid_entry.pid = perf_event_pid(event, current); 6880 data->tid_entry.tid = perf_event_tid(event, current); 6881 } 6882 6883 if (sample_type & PERF_SAMPLE_TIME) 6884 data->time = perf_event_clock(event); 6885 6886 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER)) 6887 data->id = primary_event_id(event); 6888 6889 if (sample_type & PERF_SAMPLE_STREAM_ID) 6890 data->stream_id = event->id; 6891 6892 if (sample_type & PERF_SAMPLE_CPU) { 6893 data->cpu_entry.cpu = raw_smp_processor_id(); 6894 data->cpu_entry.reserved = 0; 6895 } 6896 } 6897 6898 void perf_event_header__init_id(struct perf_event_header *header, 6899 struct perf_sample_data *data, 6900 struct perf_event *event) 6901 { 6902 if (event->attr.sample_id_all) 6903 __perf_event_header__init_id(header, data, event, event->attr.sample_type); 6904 } 6905 6906 static void __perf_event__output_id_sample(struct perf_output_handle *handle, 6907 struct perf_sample_data *data) 6908 { 6909 u64 sample_type = data->type; 6910 6911 if (sample_type & PERF_SAMPLE_TID) 6912 perf_output_put(handle, data->tid_entry); 6913 6914 if (sample_type & PERF_SAMPLE_TIME) 6915 perf_output_put(handle, data->time); 6916 6917 if (sample_type & PERF_SAMPLE_ID) 6918 perf_output_put(handle, data->id); 6919 6920 if (sample_type & PERF_SAMPLE_STREAM_ID) 6921 perf_output_put(handle, data->stream_id); 6922 6923 if (sample_type & PERF_SAMPLE_CPU) 6924 perf_output_put(handle, data->cpu_entry); 6925 6926 if (sample_type & PERF_SAMPLE_IDENTIFIER) 6927 perf_output_put(handle, data->id); 6928 } 6929 6930 void perf_event__output_id_sample(struct perf_event *event, 6931 struct perf_output_handle *handle, 6932 struct perf_sample_data *sample) 6933 { 6934 if (event->attr.sample_id_all) 6935 __perf_event__output_id_sample(handle, sample); 6936 } 6937 6938 static void perf_output_read_one(struct perf_output_handle *handle, 6939 struct perf_event *event, 6940 u64 enabled, u64 running) 6941 { 6942 u64 read_format = event->attr.read_format; 6943 u64 values[5]; 6944 int n = 0; 6945 6946 values[n++] = perf_event_count(event); 6947 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) { 6948 values[n++] = enabled + 6949 atomic64_read(&event->child_total_time_enabled); 6950 } 6951 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) { 6952 values[n++] = running + 6953 atomic64_read(&event->child_total_time_running); 6954 } 6955 if (read_format & PERF_FORMAT_ID) 6956 values[n++] = primary_event_id(event); 6957 if (read_format & PERF_FORMAT_LOST) 6958 values[n++] = atomic64_read(&event->lost_samples); 6959 6960 __output_copy(handle, values, n * sizeof(u64)); 6961 } 6962 6963 static void perf_output_read_group(struct perf_output_handle *handle, 6964 struct perf_event *event, 6965 u64 enabled, u64 running) 6966 { 6967 struct perf_event *leader = event->group_leader, *sub; 6968 u64 read_format = event->attr.read_format; 6969 unsigned long flags; 6970 u64 values[6]; 6971 int n = 0; 6972 6973 /* 6974 * Disabling interrupts avoids all counter scheduling 6975 * (context switches, timer based rotation and IPIs). 6976 */ 6977 local_irq_save(flags); 6978 6979 values[n++] = 1 + leader->nr_siblings; 6980 6981 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) 6982 values[n++] = enabled; 6983 6984 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) 6985 values[n++] = running; 6986 6987 if ((leader != event) && 6988 (leader->state == PERF_EVENT_STATE_ACTIVE)) 6989 leader->pmu->read(leader); 6990 6991 values[n++] = perf_event_count(leader); 6992 if (read_format & PERF_FORMAT_ID) 6993 values[n++] = primary_event_id(leader); 6994 if (read_format & PERF_FORMAT_LOST) 6995 values[n++] = atomic64_read(&leader->lost_samples); 6996 6997 __output_copy(handle, values, n * sizeof(u64)); 6998 6999 for_each_sibling_event(sub, leader) { 7000 n = 0; 7001 7002 if ((sub != event) && 7003 (sub->state == PERF_EVENT_STATE_ACTIVE)) 7004 sub->pmu->read(sub); 7005 7006 values[n++] = perf_event_count(sub); 7007 if (read_format & PERF_FORMAT_ID) 7008 values[n++] = primary_event_id(sub); 7009 if (read_format & PERF_FORMAT_LOST) 7010 values[n++] = atomic64_read(&sub->lost_samples); 7011 7012 __output_copy(handle, values, n * sizeof(u64)); 7013 } 7014 7015 local_irq_restore(flags); 7016 } 7017 7018 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\ 7019 PERF_FORMAT_TOTAL_TIME_RUNNING) 7020 7021 /* 7022 * XXX PERF_SAMPLE_READ vs inherited events seems difficult. 7023 * 7024 * The problem is that its both hard and excessively expensive to iterate the 7025 * child list, not to mention that its impossible to IPI the children running 7026 * on another CPU, from interrupt/NMI context. 7027 */ 7028 static void perf_output_read(struct perf_output_handle *handle, 7029 struct perf_event *event) 7030 { 7031 u64 enabled = 0, running = 0, now; 7032 u64 read_format = event->attr.read_format; 7033 7034 /* 7035 * compute total_time_enabled, total_time_running 7036 * based on snapshot values taken when the event 7037 * was last scheduled in. 7038 * 7039 * we cannot simply called update_context_time() 7040 * because of locking issue as we are called in 7041 * NMI context 7042 */ 7043 if (read_format & PERF_FORMAT_TOTAL_TIMES) 7044 calc_timer_values(event, &now, &enabled, &running); 7045 7046 if (event->attr.read_format & PERF_FORMAT_GROUP) 7047 perf_output_read_group(handle, event, enabled, running); 7048 else 7049 perf_output_read_one(handle, event, enabled, running); 7050 } 7051 7052 void perf_output_sample(struct perf_output_handle *handle, 7053 struct perf_event_header *header, 7054 struct perf_sample_data *data, 7055 struct perf_event *event) 7056 { 7057 u64 sample_type = data->type; 7058 7059 perf_output_put(handle, *header); 7060 7061 if (sample_type & PERF_SAMPLE_IDENTIFIER) 7062 perf_output_put(handle, data->id); 7063 7064 if (sample_type & PERF_SAMPLE_IP) 7065 perf_output_put(handle, data->ip); 7066 7067 if (sample_type & PERF_SAMPLE_TID) 7068 perf_output_put(handle, data->tid_entry); 7069 7070 if (sample_type & PERF_SAMPLE_TIME) 7071 perf_output_put(handle, data->time); 7072 7073 if (sample_type & PERF_SAMPLE_ADDR) 7074 perf_output_put(handle, data->addr); 7075 7076 if (sample_type & PERF_SAMPLE_ID) 7077 perf_output_put(handle, data->id); 7078 7079 if (sample_type & PERF_SAMPLE_STREAM_ID) 7080 perf_output_put(handle, data->stream_id); 7081 7082 if (sample_type & PERF_SAMPLE_CPU) 7083 perf_output_put(handle, data->cpu_entry); 7084 7085 if (sample_type & PERF_SAMPLE_PERIOD) 7086 perf_output_put(handle, data->period); 7087 7088 if (sample_type & PERF_SAMPLE_READ) 7089 perf_output_read(handle, event); 7090 7091 if (sample_type & PERF_SAMPLE_CALLCHAIN) { 7092 int size = 1; 7093 7094 size += data->callchain->nr; 7095 size *= sizeof(u64); 7096 __output_copy(handle, data->callchain, size); 7097 } 7098 7099 if (sample_type & PERF_SAMPLE_RAW) { 7100 struct perf_raw_record *raw = data->raw; 7101 7102 if (raw) { 7103 struct perf_raw_frag *frag = &raw->frag; 7104 7105 perf_output_put(handle, raw->size); 7106 do { 7107 if (frag->copy) { 7108 __output_custom(handle, frag->copy, 7109 frag->data, frag->size); 7110 } else { 7111 __output_copy(handle, frag->data, 7112 frag->size); 7113 } 7114 if (perf_raw_frag_last(frag)) 7115 break; 7116 frag = frag->next; 7117 } while (1); 7118 if (frag->pad) 7119 __output_skip(handle, NULL, frag->pad); 7120 } else { 7121 struct { 7122 u32 size; 7123 u32 data; 7124 } raw = { 7125 .size = sizeof(u32), 7126 .data = 0, 7127 }; 7128 perf_output_put(handle, raw); 7129 } 7130 } 7131 7132 if (sample_type & PERF_SAMPLE_BRANCH_STACK) { 7133 if (data->sample_flags & PERF_SAMPLE_BRANCH_STACK) { 7134 size_t size; 7135 7136 size = data->br_stack->nr 7137 * sizeof(struct perf_branch_entry); 7138 7139 perf_output_put(handle, data->br_stack->nr); 7140 if (branch_sample_hw_index(event)) 7141 perf_output_put(handle, data->br_stack->hw_idx); 7142 perf_output_copy(handle, data->br_stack->entries, size); 7143 } else { 7144 /* 7145 * we always store at least the value of nr 7146 */ 7147 u64 nr = 0; 7148 perf_output_put(handle, nr); 7149 } 7150 } 7151 7152 if (sample_type & PERF_SAMPLE_REGS_USER) { 7153 u64 abi = data->regs_user.abi; 7154 7155 /* 7156 * If there are no regs to dump, notice it through 7157 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). 7158 */ 7159 perf_output_put(handle, abi); 7160 7161 if (abi) { 7162 u64 mask = event->attr.sample_regs_user; 7163 perf_output_sample_regs(handle, 7164 data->regs_user.regs, 7165 mask); 7166 } 7167 } 7168 7169 if (sample_type & PERF_SAMPLE_STACK_USER) { 7170 perf_output_sample_ustack(handle, 7171 data->stack_user_size, 7172 data->regs_user.regs); 7173 } 7174 7175 if (sample_type & PERF_SAMPLE_WEIGHT_TYPE) 7176 perf_output_put(handle, data->weight.full); 7177 7178 if (sample_type & PERF_SAMPLE_DATA_SRC) 7179 perf_output_put(handle, data->data_src.val); 7180 7181 if (sample_type & PERF_SAMPLE_TRANSACTION) 7182 perf_output_put(handle, data->txn); 7183 7184 if (sample_type & PERF_SAMPLE_REGS_INTR) { 7185 u64 abi = data->regs_intr.abi; 7186 /* 7187 * If there are no regs to dump, notice it through 7188 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE). 7189 */ 7190 perf_output_put(handle, abi); 7191 7192 if (abi) { 7193 u64 mask = event->attr.sample_regs_intr; 7194 7195 perf_output_sample_regs(handle, 7196 data->regs_intr.regs, 7197 mask); 7198 } 7199 } 7200 7201 if (sample_type & PERF_SAMPLE_PHYS_ADDR) 7202 perf_output_put(handle, data->phys_addr); 7203 7204 if (sample_type & PERF_SAMPLE_CGROUP) 7205 perf_output_put(handle, data->cgroup); 7206 7207 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE) 7208 perf_output_put(handle, data->data_page_size); 7209 7210 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE) 7211 perf_output_put(handle, data->code_page_size); 7212 7213 if (sample_type & PERF_SAMPLE_AUX) { 7214 perf_output_put(handle, data->aux_size); 7215 7216 if (data->aux_size) 7217 perf_aux_sample_output(event, handle, data); 7218 } 7219 7220 if (!event->attr.watermark) { 7221 int wakeup_events = event->attr.wakeup_events; 7222 7223 if (wakeup_events) { 7224 struct perf_buffer *rb = handle->rb; 7225 int events = local_inc_return(&rb->events); 7226 7227 if (events >= wakeup_events) { 7228 local_sub(wakeup_events, &rb->events); 7229 local_inc(&rb->wakeup); 7230 } 7231 } 7232 } 7233 } 7234 7235 static u64 perf_virt_to_phys(u64 virt) 7236 { 7237 u64 phys_addr = 0; 7238 7239 if (!virt) 7240 return 0; 7241 7242 if (virt >= TASK_SIZE) { 7243 /* If it's vmalloc()d memory, leave phys_addr as 0 */ 7244 if (virt_addr_valid((void *)(uintptr_t)virt) && 7245 !(virt >= VMALLOC_START && virt < VMALLOC_END)) 7246 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt); 7247 } else { 7248 /* 7249 * Walking the pages tables for user address. 7250 * Interrupts are disabled, so it prevents any tear down 7251 * of the page tables. 7252 * Try IRQ-safe get_user_page_fast_only first. 7253 * If failed, leave phys_addr as 0. 7254 */ 7255 if (current->mm != NULL) { 7256 struct page *p; 7257 7258 pagefault_disable(); 7259 if (get_user_page_fast_only(virt, 0, &p)) { 7260 phys_addr = page_to_phys(p) + virt % PAGE_SIZE; 7261 put_page(p); 7262 } 7263 pagefault_enable(); 7264 } 7265 } 7266 7267 return phys_addr; 7268 } 7269 7270 /* 7271 * Return the pagetable size of a given virtual address. 7272 */ 7273 static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr) 7274 { 7275 u64 size = 0; 7276 7277 #ifdef CONFIG_HAVE_FAST_GUP 7278 pgd_t *pgdp, pgd; 7279 p4d_t *p4dp, p4d; 7280 pud_t *pudp, pud; 7281 pmd_t *pmdp, pmd; 7282 pte_t *ptep, pte; 7283 7284 pgdp = pgd_offset(mm, addr); 7285 pgd = READ_ONCE(*pgdp); 7286 if (pgd_none(pgd)) 7287 return 0; 7288 7289 if (pgd_leaf(pgd)) 7290 return pgd_leaf_size(pgd); 7291 7292 p4dp = p4d_offset_lockless(pgdp, pgd, addr); 7293 p4d = READ_ONCE(*p4dp); 7294 if (!p4d_present(p4d)) 7295 return 0; 7296 7297 if (p4d_leaf(p4d)) 7298 return p4d_leaf_size(p4d); 7299 7300 pudp = pud_offset_lockless(p4dp, p4d, addr); 7301 pud = READ_ONCE(*pudp); 7302 if (!pud_present(pud)) 7303 return 0; 7304 7305 if (pud_leaf(pud)) 7306 return pud_leaf_size(pud); 7307 7308 pmdp = pmd_offset_lockless(pudp, pud, addr); 7309 pmd = READ_ONCE(*pmdp); 7310 if (!pmd_present(pmd)) 7311 return 0; 7312 7313 if (pmd_leaf(pmd)) 7314 return pmd_leaf_size(pmd); 7315 7316 ptep = pte_offset_map(&pmd, addr); 7317 pte = ptep_get_lockless(ptep); 7318 if (pte_present(pte)) 7319 size = pte_leaf_size(pte); 7320 pte_unmap(ptep); 7321 #endif /* CONFIG_HAVE_FAST_GUP */ 7322 7323 return size; 7324 } 7325 7326 static u64 perf_get_page_size(unsigned long addr) 7327 { 7328 struct mm_struct *mm; 7329 unsigned long flags; 7330 u64 size; 7331 7332 if (!addr) 7333 return 0; 7334 7335 /* 7336 * Software page-table walkers must disable IRQs, 7337 * which prevents any tear down of the page tables. 7338 */ 7339 local_irq_save(flags); 7340 7341 mm = current->mm; 7342 if (!mm) { 7343 /* 7344 * For kernel threads and the like, use init_mm so that 7345 * we can find kernel memory. 7346 */ 7347 mm = &init_mm; 7348 } 7349 7350 size = perf_get_pgtable_size(mm, addr); 7351 7352 local_irq_restore(flags); 7353 7354 return size; 7355 } 7356 7357 static struct perf_callchain_entry __empty_callchain = { .nr = 0, }; 7358 7359 struct perf_callchain_entry * 7360 perf_callchain(struct perf_event *event, struct pt_regs *regs) 7361 { 7362 bool kernel = !event->attr.exclude_callchain_kernel; 7363 bool user = !event->attr.exclude_callchain_user; 7364 /* Disallow cross-task user callchains. */ 7365 bool crosstask = event->ctx->task && event->ctx->task != current; 7366 const u32 max_stack = event->attr.sample_max_stack; 7367 struct perf_callchain_entry *callchain; 7368 7369 if (!kernel && !user) 7370 return &__empty_callchain; 7371 7372 callchain = get_perf_callchain(regs, 0, kernel, user, 7373 max_stack, crosstask, true); 7374 return callchain ?: &__empty_callchain; 7375 } 7376 7377 void perf_prepare_sample(struct perf_event_header *header, 7378 struct perf_sample_data *data, 7379 struct perf_event *event, 7380 struct pt_regs *regs) 7381 { 7382 u64 sample_type = event->attr.sample_type; 7383 u64 filtered_sample_type; 7384 7385 header->type = PERF_RECORD_SAMPLE; 7386 header->size = sizeof(*header) + event->header_size; 7387 7388 header->misc = 0; 7389 header->misc |= perf_misc_flags(regs); 7390 7391 /* 7392 * Clear the sample flags that have already been done by the 7393 * PMU driver. 7394 */ 7395 filtered_sample_type = sample_type & ~data->sample_flags; 7396 __perf_event_header__init_id(header, data, event, filtered_sample_type); 7397 7398 if (sample_type & (PERF_SAMPLE_IP | PERF_SAMPLE_CODE_PAGE_SIZE)) 7399 data->ip = perf_instruction_pointer(regs); 7400 7401 if (sample_type & PERF_SAMPLE_CALLCHAIN) { 7402 int size = 1; 7403 7404 if (filtered_sample_type & PERF_SAMPLE_CALLCHAIN) 7405 data->callchain = perf_callchain(event, regs); 7406 7407 size += data->callchain->nr; 7408 7409 header->size += size * sizeof(u64); 7410 } 7411 7412 if (sample_type & PERF_SAMPLE_RAW) { 7413 struct perf_raw_record *raw = data->raw; 7414 int size; 7415 7416 if (raw && (data->sample_flags & PERF_SAMPLE_RAW)) { 7417 struct perf_raw_frag *frag = &raw->frag; 7418 u32 sum = 0; 7419 7420 do { 7421 sum += frag->size; 7422 if (perf_raw_frag_last(frag)) 7423 break; 7424 frag = frag->next; 7425 } while (1); 7426 7427 size = round_up(sum + sizeof(u32), sizeof(u64)); 7428 raw->size = size - sizeof(u32); 7429 frag->pad = raw->size - sum; 7430 } else { 7431 size = sizeof(u64); 7432 data->raw = NULL; 7433 } 7434 7435 header->size += size; 7436 } 7437 7438 if (sample_type & PERF_SAMPLE_BRANCH_STACK) { 7439 int size = sizeof(u64); /* nr */ 7440 if (data->sample_flags & PERF_SAMPLE_BRANCH_STACK) { 7441 if (branch_sample_hw_index(event)) 7442 size += sizeof(u64); 7443 7444 size += data->br_stack->nr 7445 * sizeof(struct perf_branch_entry); 7446 } 7447 header->size += size; 7448 } 7449 7450 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER)) 7451 perf_sample_regs_user(&data->regs_user, regs); 7452 7453 if (sample_type & PERF_SAMPLE_REGS_USER) { 7454 /* regs dump ABI info */ 7455 int size = sizeof(u64); 7456 7457 if (data->regs_user.regs) { 7458 u64 mask = event->attr.sample_regs_user; 7459 size += hweight64(mask) * sizeof(u64); 7460 } 7461 7462 header->size += size; 7463 } 7464 7465 if (sample_type & PERF_SAMPLE_STACK_USER) { 7466 /* 7467 * Either we need PERF_SAMPLE_STACK_USER bit to be always 7468 * processed as the last one or have additional check added 7469 * in case new sample type is added, because we could eat 7470 * up the rest of the sample size. 7471 */ 7472 u16 stack_size = event->attr.sample_stack_user; 7473 u16 size = sizeof(u64); 7474 7475 stack_size = perf_sample_ustack_size(stack_size, header->size, 7476 data->regs_user.regs); 7477 7478 /* 7479 * If there is something to dump, add space for the dump 7480 * itself and for the field that tells the dynamic size, 7481 * which is how many have been actually dumped. 7482 */ 7483 if (stack_size) 7484 size += sizeof(u64) + stack_size; 7485 7486 data->stack_user_size = stack_size; 7487 header->size += size; 7488 } 7489 7490 if (filtered_sample_type & PERF_SAMPLE_WEIGHT_TYPE) 7491 data->weight.full = 0; 7492 7493 if (filtered_sample_type & PERF_SAMPLE_DATA_SRC) 7494 data->data_src.val = PERF_MEM_NA; 7495 7496 if (filtered_sample_type & PERF_SAMPLE_TRANSACTION) 7497 data->txn = 0; 7498 7499 if (sample_type & (PERF_SAMPLE_ADDR | PERF_SAMPLE_PHYS_ADDR | PERF_SAMPLE_DATA_PAGE_SIZE)) { 7500 if (filtered_sample_type & PERF_SAMPLE_ADDR) 7501 data->addr = 0; 7502 } 7503 7504 if (sample_type & PERF_SAMPLE_REGS_INTR) { 7505 /* regs dump ABI info */ 7506 int size = sizeof(u64); 7507 7508 perf_sample_regs_intr(&data->regs_intr, regs); 7509 7510 if (data->regs_intr.regs) { 7511 u64 mask = event->attr.sample_regs_intr; 7512 7513 size += hweight64(mask) * sizeof(u64); 7514 } 7515 7516 header->size += size; 7517 } 7518 7519 if (sample_type & PERF_SAMPLE_PHYS_ADDR && 7520 filtered_sample_type & PERF_SAMPLE_PHYS_ADDR) 7521 data->phys_addr = perf_virt_to_phys(data->addr); 7522 7523 #ifdef CONFIG_CGROUP_PERF 7524 if (sample_type & PERF_SAMPLE_CGROUP) { 7525 struct cgroup *cgrp; 7526 7527 /* protected by RCU */ 7528 cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup; 7529 data->cgroup = cgroup_id(cgrp); 7530 } 7531 #endif 7532 7533 /* 7534 * PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't 7535 * require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr, 7536 * but the value will not dump to the userspace. 7537 */ 7538 if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE) 7539 data->data_page_size = perf_get_page_size(data->addr); 7540 7541 if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE) 7542 data->code_page_size = perf_get_page_size(data->ip); 7543 7544 if (sample_type & PERF_SAMPLE_AUX) { 7545 u64 size; 7546 7547 header->size += sizeof(u64); /* size */ 7548 7549 /* 7550 * Given the 16bit nature of header::size, an AUX sample can 7551 * easily overflow it, what with all the preceding sample bits. 7552 * Make sure this doesn't happen by using up to U16_MAX bytes 7553 * per sample in total (rounded down to 8 byte boundary). 7554 */ 7555 size = min_t(size_t, U16_MAX - header->size, 7556 event->attr.aux_sample_size); 7557 size = rounddown(size, 8); 7558 size = perf_prepare_sample_aux(event, data, size); 7559 7560 WARN_ON_ONCE(size + header->size > U16_MAX); 7561 header->size += size; 7562 } 7563 /* 7564 * If you're adding more sample types here, you likely need to do 7565 * something about the overflowing header::size, like repurpose the 7566 * lowest 3 bits of size, which should be always zero at the moment. 7567 * This raises a more important question, do we really need 512k sized 7568 * samples and why, so good argumentation is in order for whatever you 7569 * do here next. 7570 */ 7571 WARN_ON_ONCE(header->size & 7); 7572 } 7573 7574 static __always_inline int 7575 __perf_event_output(struct perf_event *event, 7576 struct perf_sample_data *data, 7577 struct pt_regs *regs, 7578 int (*output_begin)(struct perf_output_handle *, 7579 struct perf_sample_data *, 7580 struct perf_event *, 7581 unsigned int)) 7582 { 7583 struct perf_output_handle handle; 7584 struct perf_event_header header; 7585 int err; 7586 7587 /* protect the callchain buffers */ 7588 rcu_read_lock(); 7589 7590 perf_prepare_sample(&header, data, event, regs); 7591 7592 err = output_begin(&handle, data, event, header.size); 7593 if (err) 7594 goto exit; 7595 7596 perf_output_sample(&handle, &header, data, event); 7597 7598 perf_output_end(&handle); 7599 7600 exit: 7601 rcu_read_unlock(); 7602 return err; 7603 } 7604 7605 void 7606 perf_event_output_forward(struct perf_event *event, 7607 struct perf_sample_data *data, 7608 struct pt_regs *regs) 7609 { 7610 __perf_event_output(event, data, regs, perf_output_begin_forward); 7611 } 7612 7613 void 7614 perf_event_output_backward(struct perf_event *event, 7615 struct perf_sample_data *data, 7616 struct pt_regs *regs) 7617 { 7618 __perf_event_output(event, data, regs, perf_output_begin_backward); 7619 } 7620 7621 int 7622 perf_event_output(struct perf_event *event, 7623 struct perf_sample_data *data, 7624 struct pt_regs *regs) 7625 { 7626 return __perf_event_output(event, data, regs, perf_output_begin); 7627 } 7628 7629 /* 7630 * read event_id 7631 */ 7632 7633 struct perf_read_event { 7634 struct perf_event_header header; 7635 7636 u32 pid; 7637 u32 tid; 7638 }; 7639 7640 static void 7641 perf_event_read_event(struct perf_event *event, 7642 struct task_struct *task) 7643 { 7644 struct perf_output_handle handle; 7645 struct perf_sample_data sample; 7646 struct perf_read_event read_event = { 7647 .header = { 7648 .type = PERF_RECORD_READ, 7649 .misc = 0, 7650 .size = sizeof(read_event) + event->read_size, 7651 }, 7652 .pid = perf_event_pid(event, task), 7653 .tid = perf_event_tid(event, task), 7654 }; 7655 int ret; 7656 7657 perf_event_header__init_id(&read_event.header, &sample, event); 7658 ret = perf_output_begin(&handle, &sample, event, read_event.header.size); 7659 if (ret) 7660 return; 7661 7662 perf_output_put(&handle, read_event); 7663 perf_output_read(&handle, event); 7664 perf_event__output_id_sample(event, &handle, &sample); 7665 7666 perf_output_end(&handle); 7667 } 7668 7669 typedef void (perf_iterate_f)(struct perf_event *event, void *data); 7670 7671 static void 7672 perf_iterate_ctx(struct perf_event_context *ctx, 7673 perf_iterate_f output, 7674 void *data, bool all) 7675 { 7676 struct perf_event *event; 7677 7678 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 7679 if (!all) { 7680 if (event->state < PERF_EVENT_STATE_INACTIVE) 7681 continue; 7682 if (!event_filter_match(event)) 7683 continue; 7684 } 7685 7686 output(event, data); 7687 } 7688 } 7689 7690 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data) 7691 { 7692 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events); 7693 struct perf_event *event; 7694 7695 list_for_each_entry_rcu(event, &pel->list, sb_list) { 7696 /* 7697 * Skip events that are not fully formed yet; ensure that 7698 * if we observe event->ctx, both event and ctx will be 7699 * complete enough. See perf_install_in_context(). 7700 */ 7701 if (!smp_load_acquire(&event->ctx)) 7702 continue; 7703 7704 if (event->state < PERF_EVENT_STATE_INACTIVE) 7705 continue; 7706 if (!event_filter_match(event)) 7707 continue; 7708 output(event, data); 7709 } 7710 } 7711 7712 /* 7713 * Iterate all events that need to receive side-band events. 7714 * 7715 * For new callers; ensure that account_pmu_sb_event() includes 7716 * your event, otherwise it might not get delivered. 7717 */ 7718 static void 7719 perf_iterate_sb(perf_iterate_f output, void *data, 7720 struct perf_event_context *task_ctx) 7721 { 7722 struct perf_event_context *ctx; 7723 int ctxn; 7724 7725 rcu_read_lock(); 7726 preempt_disable(); 7727 7728 /* 7729 * If we have task_ctx != NULL we only notify the task context itself. 7730 * The task_ctx is set only for EXIT events before releasing task 7731 * context. 7732 */ 7733 if (task_ctx) { 7734 perf_iterate_ctx(task_ctx, output, data, false); 7735 goto done; 7736 } 7737 7738 perf_iterate_sb_cpu(output, data); 7739 7740 for_each_task_context_nr(ctxn) { 7741 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); 7742 if (ctx) 7743 perf_iterate_ctx(ctx, output, data, false); 7744 } 7745 done: 7746 preempt_enable(); 7747 rcu_read_unlock(); 7748 } 7749 7750 /* 7751 * Clear all file-based filters at exec, they'll have to be 7752 * re-instated when/if these objects are mmapped again. 7753 */ 7754 static void perf_event_addr_filters_exec(struct perf_event *event, void *data) 7755 { 7756 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 7757 struct perf_addr_filter *filter; 7758 unsigned int restart = 0, count = 0; 7759 unsigned long flags; 7760 7761 if (!has_addr_filter(event)) 7762 return; 7763 7764 raw_spin_lock_irqsave(&ifh->lock, flags); 7765 list_for_each_entry(filter, &ifh->list, entry) { 7766 if (filter->path.dentry) { 7767 event->addr_filter_ranges[count].start = 0; 7768 event->addr_filter_ranges[count].size = 0; 7769 restart++; 7770 } 7771 7772 count++; 7773 } 7774 7775 if (restart) 7776 event->addr_filters_gen++; 7777 raw_spin_unlock_irqrestore(&ifh->lock, flags); 7778 7779 if (restart) 7780 perf_event_stop(event, 1); 7781 } 7782 7783 void perf_event_exec(void) 7784 { 7785 struct perf_event_context *ctx; 7786 int ctxn; 7787 7788 for_each_task_context_nr(ctxn) { 7789 perf_event_enable_on_exec(ctxn); 7790 perf_event_remove_on_exec(ctxn); 7791 7792 rcu_read_lock(); 7793 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); 7794 if (ctx) { 7795 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, 7796 NULL, true); 7797 } 7798 rcu_read_unlock(); 7799 } 7800 } 7801 7802 struct remote_output { 7803 struct perf_buffer *rb; 7804 int err; 7805 }; 7806 7807 static void __perf_event_output_stop(struct perf_event *event, void *data) 7808 { 7809 struct perf_event *parent = event->parent; 7810 struct remote_output *ro = data; 7811 struct perf_buffer *rb = ro->rb; 7812 struct stop_event_data sd = { 7813 .event = event, 7814 }; 7815 7816 if (!has_aux(event)) 7817 return; 7818 7819 if (!parent) 7820 parent = event; 7821 7822 /* 7823 * In case of inheritance, it will be the parent that links to the 7824 * ring-buffer, but it will be the child that's actually using it. 7825 * 7826 * We are using event::rb to determine if the event should be stopped, 7827 * however this may race with ring_buffer_attach() (through set_output), 7828 * which will make us skip the event that actually needs to be stopped. 7829 * So ring_buffer_attach() has to stop an aux event before re-assigning 7830 * its rb pointer. 7831 */ 7832 if (rcu_dereference(parent->rb) == rb) 7833 ro->err = __perf_event_stop(&sd); 7834 } 7835 7836 static int __perf_pmu_output_stop(void *info) 7837 { 7838 struct perf_event *event = info; 7839 struct pmu *pmu = event->ctx->pmu; 7840 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); 7841 struct remote_output ro = { 7842 .rb = event->rb, 7843 }; 7844 7845 rcu_read_lock(); 7846 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false); 7847 if (cpuctx->task_ctx) 7848 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop, 7849 &ro, false); 7850 rcu_read_unlock(); 7851 7852 return ro.err; 7853 } 7854 7855 static void perf_pmu_output_stop(struct perf_event *event) 7856 { 7857 struct perf_event *iter; 7858 int err, cpu; 7859 7860 restart: 7861 rcu_read_lock(); 7862 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) { 7863 /* 7864 * For per-CPU events, we need to make sure that neither they 7865 * nor their children are running; for cpu==-1 events it's 7866 * sufficient to stop the event itself if it's active, since 7867 * it can't have children. 7868 */ 7869 cpu = iter->cpu; 7870 if (cpu == -1) 7871 cpu = READ_ONCE(iter->oncpu); 7872 7873 if (cpu == -1) 7874 continue; 7875 7876 err = cpu_function_call(cpu, __perf_pmu_output_stop, event); 7877 if (err == -EAGAIN) { 7878 rcu_read_unlock(); 7879 goto restart; 7880 } 7881 } 7882 rcu_read_unlock(); 7883 } 7884 7885 /* 7886 * task tracking -- fork/exit 7887 * 7888 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task 7889 */ 7890 7891 struct perf_task_event { 7892 struct task_struct *task; 7893 struct perf_event_context *task_ctx; 7894 7895 struct { 7896 struct perf_event_header header; 7897 7898 u32 pid; 7899 u32 ppid; 7900 u32 tid; 7901 u32 ptid; 7902 u64 time; 7903 } event_id; 7904 }; 7905 7906 static int perf_event_task_match(struct perf_event *event) 7907 { 7908 return event->attr.comm || event->attr.mmap || 7909 event->attr.mmap2 || event->attr.mmap_data || 7910 event->attr.task; 7911 } 7912 7913 static void perf_event_task_output(struct perf_event *event, 7914 void *data) 7915 { 7916 struct perf_task_event *task_event = data; 7917 struct perf_output_handle handle; 7918 struct perf_sample_data sample; 7919 struct task_struct *task = task_event->task; 7920 int ret, size = task_event->event_id.header.size; 7921 7922 if (!perf_event_task_match(event)) 7923 return; 7924 7925 perf_event_header__init_id(&task_event->event_id.header, &sample, event); 7926 7927 ret = perf_output_begin(&handle, &sample, event, 7928 task_event->event_id.header.size); 7929 if (ret) 7930 goto out; 7931 7932 task_event->event_id.pid = perf_event_pid(event, task); 7933 task_event->event_id.tid = perf_event_tid(event, task); 7934 7935 if (task_event->event_id.header.type == PERF_RECORD_EXIT) { 7936 task_event->event_id.ppid = perf_event_pid(event, 7937 task->real_parent); 7938 task_event->event_id.ptid = perf_event_pid(event, 7939 task->real_parent); 7940 } else { /* PERF_RECORD_FORK */ 7941 task_event->event_id.ppid = perf_event_pid(event, current); 7942 task_event->event_id.ptid = perf_event_tid(event, current); 7943 } 7944 7945 task_event->event_id.time = perf_event_clock(event); 7946 7947 perf_output_put(&handle, task_event->event_id); 7948 7949 perf_event__output_id_sample(event, &handle, &sample); 7950 7951 perf_output_end(&handle); 7952 out: 7953 task_event->event_id.header.size = size; 7954 } 7955 7956 static void perf_event_task(struct task_struct *task, 7957 struct perf_event_context *task_ctx, 7958 int new) 7959 { 7960 struct perf_task_event task_event; 7961 7962 if (!atomic_read(&nr_comm_events) && 7963 !atomic_read(&nr_mmap_events) && 7964 !atomic_read(&nr_task_events)) 7965 return; 7966 7967 task_event = (struct perf_task_event){ 7968 .task = task, 7969 .task_ctx = task_ctx, 7970 .event_id = { 7971 .header = { 7972 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT, 7973 .misc = 0, 7974 .size = sizeof(task_event.event_id), 7975 }, 7976 /* .pid */ 7977 /* .ppid */ 7978 /* .tid */ 7979 /* .ptid */ 7980 /* .time */ 7981 }, 7982 }; 7983 7984 perf_iterate_sb(perf_event_task_output, 7985 &task_event, 7986 task_ctx); 7987 } 7988 7989 void perf_event_fork(struct task_struct *task) 7990 { 7991 perf_event_task(task, NULL, 1); 7992 perf_event_namespaces(task); 7993 } 7994 7995 /* 7996 * comm tracking 7997 */ 7998 7999 struct perf_comm_event { 8000 struct task_struct *task; 8001 char *comm; 8002 int comm_size; 8003 8004 struct { 8005 struct perf_event_header header; 8006 8007 u32 pid; 8008 u32 tid; 8009 } event_id; 8010 }; 8011 8012 static int perf_event_comm_match(struct perf_event *event) 8013 { 8014 return event->attr.comm; 8015 } 8016 8017 static void perf_event_comm_output(struct perf_event *event, 8018 void *data) 8019 { 8020 struct perf_comm_event *comm_event = data; 8021 struct perf_output_handle handle; 8022 struct perf_sample_data sample; 8023 int size = comm_event->event_id.header.size; 8024 int ret; 8025 8026 if (!perf_event_comm_match(event)) 8027 return; 8028 8029 perf_event_header__init_id(&comm_event->event_id.header, &sample, event); 8030 ret = perf_output_begin(&handle, &sample, event, 8031 comm_event->event_id.header.size); 8032 8033 if (ret) 8034 goto out; 8035 8036 comm_event->event_id.pid = perf_event_pid(event, comm_event->task); 8037 comm_event->event_id.tid = perf_event_tid(event, comm_event->task); 8038 8039 perf_output_put(&handle, comm_event->event_id); 8040 __output_copy(&handle, comm_event->comm, 8041 comm_event->comm_size); 8042 8043 perf_event__output_id_sample(event, &handle, &sample); 8044 8045 perf_output_end(&handle); 8046 out: 8047 comm_event->event_id.header.size = size; 8048 } 8049 8050 static void perf_event_comm_event(struct perf_comm_event *comm_event) 8051 { 8052 char comm[TASK_COMM_LEN]; 8053 unsigned int size; 8054 8055 memset(comm, 0, sizeof(comm)); 8056 strlcpy(comm, comm_event->task->comm, sizeof(comm)); 8057 size = ALIGN(strlen(comm)+1, sizeof(u64)); 8058 8059 comm_event->comm = comm; 8060 comm_event->comm_size = size; 8061 8062 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size; 8063 8064 perf_iterate_sb(perf_event_comm_output, 8065 comm_event, 8066 NULL); 8067 } 8068 8069 void perf_event_comm(struct task_struct *task, bool exec) 8070 { 8071 struct perf_comm_event comm_event; 8072 8073 if (!atomic_read(&nr_comm_events)) 8074 return; 8075 8076 comm_event = (struct perf_comm_event){ 8077 .task = task, 8078 /* .comm */ 8079 /* .comm_size */ 8080 .event_id = { 8081 .header = { 8082 .type = PERF_RECORD_COMM, 8083 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0, 8084 /* .size */ 8085 }, 8086 /* .pid */ 8087 /* .tid */ 8088 }, 8089 }; 8090 8091 perf_event_comm_event(&comm_event); 8092 } 8093 8094 /* 8095 * namespaces tracking 8096 */ 8097 8098 struct perf_namespaces_event { 8099 struct task_struct *task; 8100 8101 struct { 8102 struct perf_event_header header; 8103 8104 u32 pid; 8105 u32 tid; 8106 u64 nr_namespaces; 8107 struct perf_ns_link_info link_info[NR_NAMESPACES]; 8108 } event_id; 8109 }; 8110 8111 static int perf_event_namespaces_match(struct perf_event *event) 8112 { 8113 return event->attr.namespaces; 8114 } 8115 8116 static void perf_event_namespaces_output(struct perf_event *event, 8117 void *data) 8118 { 8119 struct perf_namespaces_event *namespaces_event = data; 8120 struct perf_output_handle handle; 8121 struct perf_sample_data sample; 8122 u16 header_size = namespaces_event->event_id.header.size; 8123 int ret; 8124 8125 if (!perf_event_namespaces_match(event)) 8126 return; 8127 8128 perf_event_header__init_id(&namespaces_event->event_id.header, 8129 &sample, event); 8130 ret = perf_output_begin(&handle, &sample, event, 8131 namespaces_event->event_id.header.size); 8132 if (ret) 8133 goto out; 8134 8135 namespaces_event->event_id.pid = perf_event_pid(event, 8136 namespaces_event->task); 8137 namespaces_event->event_id.tid = perf_event_tid(event, 8138 namespaces_event->task); 8139 8140 perf_output_put(&handle, namespaces_event->event_id); 8141 8142 perf_event__output_id_sample(event, &handle, &sample); 8143 8144 perf_output_end(&handle); 8145 out: 8146 namespaces_event->event_id.header.size = header_size; 8147 } 8148 8149 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info, 8150 struct task_struct *task, 8151 const struct proc_ns_operations *ns_ops) 8152 { 8153 struct path ns_path; 8154 struct inode *ns_inode; 8155 int error; 8156 8157 error = ns_get_path(&ns_path, task, ns_ops); 8158 if (!error) { 8159 ns_inode = ns_path.dentry->d_inode; 8160 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev); 8161 ns_link_info->ino = ns_inode->i_ino; 8162 path_put(&ns_path); 8163 } 8164 } 8165 8166 void perf_event_namespaces(struct task_struct *task) 8167 { 8168 struct perf_namespaces_event namespaces_event; 8169 struct perf_ns_link_info *ns_link_info; 8170 8171 if (!atomic_read(&nr_namespaces_events)) 8172 return; 8173 8174 namespaces_event = (struct perf_namespaces_event){ 8175 .task = task, 8176 .event_id = { 8177 .header = { 8178 .type = PERF_RECORD_NAMESPACES, 8179 .misc = 0, 8180 .size = sizeof(namespaces_event.event_id), 8181 }, 8182 /* .pid */ 8183 /* .tid */ 8184 .nr_namespaces = NR_NAMESPACES, 8185 /* .link_info[NR_NAMESPACES] */ 8186 }, 8187 }; 8188 8189 ns_link_info = namespaces_event.event_id.link_info; 8190 8191 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX], 8192 task, &mntns_operations); 8193 8194 #ifdef CONFIG_USER_NS 8195 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX], 8196 task, &userns_operations); 8197 #endif 8198 #ifdef CONFIG_NET_NS 8199 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX], 8200 task, &netns_operations); 8201 #endif 8202 #ifdef CONFIG_UTS_NS 8203 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX], 8204 task, &utsns_operations); 8205 #endif 8206 #ifdef CONFIG_IPC_NS 8207 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX], 8208 task, &ipcns_operations); 8209 #endif 8210 #ifdef CONFIG_PID_NS 8211 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX], 8212 task, &pidns_operations); 8213 #endif 8214 #ifdef CONFIG_CGROUPS 8215 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX], 8216 task, &cgroupns_operations); 8217 #endif 8218 8219 perf_iterate_sb(perf_event_namespaces_output, 8220 &namespaces_event, 8221 NULL); 8222 } 8223 8224 /* 8225 * cgroup tracking 8226 */ 8227 #ifdef CONFIG_CGROUP_PERF 8228 8229 struct perf_cgroup_event { 8230 char *path; 8231 int path_size; 8232 struct { 8233 struct perf_event_header header; 8234 u64 id; 8235 char path[]; 8236 } event_id; 8237 }; 8238 8239 static int perf_event_cgroup_match(struct perf_event *event) 8240 { 8241 return event->attr.cgroup; 8242 } 8243 8244 static void perf_event_cgroup_output(struct perf_event *event, void *data) 8245 { 8246 struct perf_cgroup_event *cgroup_event = data; 8247 struct perf_output_handle handle; 8248 struct perf_sample_data sample; 8249 u16 header_size = cgroup_event->event_id.header.size; 8250 int ret; 8251 8252 if (!perf_event_cgroup_match(event)) 8253 return; 8254 8255 perf_event_header__init_id(&cgroup_event->event_id.header, 8256 &sample, event); 8257 ret = perf_output_begin(&handle, &sample, event, 8258 cgroup_event->event_id.header.size); 8259 if (ret) 8260 goto out; 8261 8262 perf_output_put(&handle, cgroup_event->event_id); 8263 __output_copy(&handle, cgroup_event->path, cgroup_event->path_size); 8264 8265 perf_event__output_id_sample(event, &handle, &sample); 8266 8267 perf_output_end(&handle); 8268 out: 8269 cgroup_event->event_id.header.size = header_size; 8270 } 8271 8272 static void perf_event_cgroup(struct cgroup *cgrp) 8273 { 8274 struct perf_cgroup_event cgroup_event; 8275 char path_enomem[16] = "//enomem"; 8276 char *pathname; 8277 size_t size; 8278 8279 if (!atomic_read(&nr_cgroup_events)) 8280 return; 8281 8282 cgroup_event = (struct perf_cgroup_event){ 8283 .event_id = { 8284 .header = { 8285 .type = PERF_RECORD_CGROUP, 8286 .misc = 0, 8287 .size = sizeof(cgroup_event.event_id), 8288 }, 8289 .id = cgroup_id(cgrp), 8290 }, 8291 }; 8292 8293 pathname = kmalloc(PATH_MAX, GFP_KERNEL); 8294 if (pathname == NULL) { 8295 cgroup_event.path = path_enomem; 8296 } else { 8297 /* just to be sure to have enough space for alignment */ 8298 cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64)); 8299 cgroup_event.path = pathname; 8300 } 8301 8302 /* 8303 * Since our buffer works in 8 byte units we need to align our string 8304 * size to a multiple of 8. However, we must guarantee the tail end is 8305 * zero'd out to avoid leaking random bits to userspace. 8306 */ 8307 size = strlen(cgroup_event.path) + 1; 8308 while (!IS_ALIGNED(size, sizeof(u64))) 8309 cgroup_event.path[size++] = '\0'; 8310 8311 cgroup_event.event_id.header.size += size; 8312 cgroup_event.path_size = size; 8313 8314 perf_iterate_sb(perf_event_cgroup_output, 8315 &cgroup_event, 8316 NULL); 8317 8318 kfree(pathname); 8319 } 8320 8321 #endif 8322 8323 /* 8324 * mmap tracking 8325 */ 8326 8327 struct perf_mmap_event { 8328 struct vm_area_struct *vma; 8329 8330 const char *file_name; 8331 int file_size; 8332 int maj, min; 8333 u64 ino; 8334 u64 ino_generation; 8335 u32 prot, flags; 8336 u8 build_id[BUILD_ID_SIZE_MAX]; 8337 u32 build_id_size; 8338 8339 struct { 8340 struct perf_event_header header; 8341 8342 u32 pid; 8343 u32 tid; 8344 u64 start; 8345 u64 len; 8346 u64 pgoff; 8347 } event_id; 8348 }; 8349 8350 static int perf_event_mmap_match(struct perf_event *event, 8351 void *data) 8352 { 8353 struct perf_mmap_event *mmap_event = data; 8354 struct vm_area_struct *vma = mmap_event->vma; 8355 int executable = vma->vm_flags & VM_EXEC; 8356 8357 return (!executable && event->attr.mmap_data) || 8358 (executable && (event->attr.mmap || event->attr.mmap2)); 8359 } 8360 8361 static void perf_event_mmap_output(struct perf_event *event, 8362 void *data) 8363 { 8364 struct perf_mmap_event *mmap_event = data; 8365 struct perf_output_handle handle; 8366 struct perf_sample_data sample; 8367 int size = mmap_event->event_id.header.size; 8368 u32 type = mmap_event->event_id.header.type; 8369 bool use_build_id; 8370 int ret; 8371 8372 if (!perf_event_mmap_match(event, data)) 8373 return; 8374 8375 if (event->attr.mmap2) { 8376 mmap_event->event_id.header.type = PERF_RECORD_MMAP2; 8377 mmap_event->event_id.header.size += sizeof(mmap_event->maj); 8378 mmap_event->event_id.header.size += sizeof(mmap_event->min); 8379 mmap_event->event_id.header.size += sizeof(mmap_event->ino); 8380 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation); 8381 mmap_event->event_id.header.size += sizeof(mmap_event->prot); 8382 mmap_event->event_id.header.size += sizeof(mmap_event->flags); 8383 } 8384 8385 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event); 8386 ret = perf_output_begin(&handle, &sample, event, 8387 mmap_event->event_id.header.size); 8388 if (ret) 8389 goto out; 8390 8391 mmap_event->event_id.pid = perf_event_pid(event, current); 8392 mmap_event->event_id.tid = perf_event_tid(event, current); 8393 8394 use_build_id = event->attr.build_id && mmap_event->build_id_size; 8395 8396 if (event->attr.mmap2 && use_build_id) 8397 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID; 8398 8399 perf_output_put(&handle, mmap_event->event_id); 8400 8401 if (event->attr.mmap2) { 8402 if (use_build_id) { 8403 u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 }; 8404 8405 __output_copy(&handle, size, 4); 8406 __output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX); 8407 } else { 8408 perf_output_put(&handle, mmap_event->maj); 8409 perf_output_put(&handle, mmap_event->min); 8410 perf_output_put(&handle, mmap_event->ino); 8411 perf_output_put(&handle, mmap_event->ino_generation); 8412 } 8413 perf_output_put(&handle, mmap_event->prot); 8414 perf_output_put(&handle, mmap_event->flags); 8415 } 8416 8417 __output_copy(&handle, mmap_event->file_name, 8418 mmap_event->file_size); 8419 8420 perf_event__output_id_sample(event, &handle, &sample); 8421 8422 perf_output_end(&handle); 8423 out: 8424 mmap_event->event_id.header.size = size; 8425 mmap_event->event_id.header.type = type; 8426 } 8427 8428 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) 8429 { 8430 struct vm_area_struct *vma = mmap_event->vma; 8431 struct file *file = vma->vm_file; 8432 int maj = 0, min = 0; 8433 u64 ino = 0, gen = 0; 8434 u32 prot = 0, flags = 0; 8435 unsigned int size; 8436 char tmp[16]; 8437 char *buf = NULL; 8438 char *name; 8439 8440 if (vma->vm_flags & VM_READ) 8441 prot |= PROT_READ; 8442 if (vma->vm_flags & VM_WRITE) 8443 prot |= PROT_WRITE; 8444 if (vma->vm_flags & VM_EXEC) 8445 prot |= PROT_EXEC; 8446 8447 if (vma->vm_flags & VM_MAYSHARE) 8448 flags = MAP_SHARED; 8449 else 8450 flags = MAP_PRIVATE; 8451 8452 if (vma->vm_flags & VM_LOCKED) 8453 flags |= MAP_LOCKED; 8454 if (is_vm_hugetlb_page(vma)) 8455 flags |= MAP_HUGETLB; 8456 8457 if (file) { 8458 struct inode *inode; 8459 dev_t dev; 8460 8461 buf = kmalloc(PATH_MAX, GFP_KERNEL); 8462 if (!buf) { 8463 name = "//enomem"; 8464 goto cpy_name; 8465 } 8466 /* 8467 * d_path() works from the end of the rb backwards, so we 8468 * need to add enough zero bytes after the string to handle 8469 * the 64bit alignment we do later. 8470 */ 8471 name = file_path(file, buf, PATH_MAX - sizeof(u64)); 8472 if (IS_ERR(name)) { 8473 name = "//toolong"; 8474 goto cpy_name; 8475 } 8476 inode = file_inode(vma->vm_file); 8477 dev = inode->i_sb->s_dev; 8478 ino = inode->i_ino; 8479 gen = inode->i_generation; 8480 maj = MAJOR(dev); 8481 min = MINOR(dev); 8482 8483 goto got_name; 8484 } else { 8485 if (vma->vm_ops && vma->vm_ops->name) { 8486 name = (char *) vma->vm_ops->name(vma); 8487 if (name) 8488 goto cpy_name; 8489 } 8490 8491 name = (char *)arch_vma_name(vma); 8492 if (name) 8493 goto cpy_name; 8494 8495 if (vma->vm_start <= vma->vm_mm->start_brk && 8496 vma->vm_end >= vma->vm_mm->brk) { 8497 name = "[heap]"; 8498 goto cpy_name; 8499 } 8500 if (vma->vm_start <= vma->vm_mm->start_stack && 8501 vma->vm_end >= vma->vm_mm->start_stack) { 8502 name = "[stack]"; 8503 goto cpy_name; 8504 } 8505 8506 name = "//anon"; 8507 goto cpy_name; 8508 } 8509 8510 cpy_name: 8511 strlcpy(tmp, name, sizeof(tmp)); 8512 name = tmp; 8513 got_name: 8514 /* 8515 * Since our buffer works in 8 byte units we need to align our string 8516 * size to a multiple of 8. However, we must guarantee the tail end is 8517 * zero'd out to avoid leaking random bits to userspace. 8518 */ 8519 size = strlen(name)+1; 8520 while (!IS_ALIGNED(size, sizeof(u64))) 8521 name[size++] = '\0'; 8522 8523 mmap_event->file_name = name; 8524 mmap_event->file_size = size; 8525 mmap_event->maj = maj; 8526 mmap_event->min = min; 8527 mmap_event->ino = ino; 8528 mmap_event->ino_generation = gen; 8529 mmap_event->prot = prot; 8530 mmap_event->flags = flags; 8531 8532 if (!(vma->vm_flags & VM_EXEC)) 8533 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA; 8534 8535 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size; 8536 8537 if (atomic_read(&nr_build_id_events)) 8538 build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size); 8539 8540 perf_iterate_sb(perf_event_mmap_output, 8541 mmap_event, 8542 NULL); 8543 8544 kfree(buf); 8545 } 8546 8547 /* 8548 * Check whether inode and address range match filter criteria. 8549 */ 8550 static bool perf_addr_filter_match(struct perf_addr_filter *filter, 8551 struct file *file, unsigned long offset, 8552 unsigned long size) 8553 { 8554 /* d_inode(NULL) won't be equal to any mapped user-space file */ 8555 if (!filter->path.dentry) 8556 return false; 8557 8558 if (d_inode(filter->path.dentry) != file_inode(file)) 8559 return false; 8560 8561 if (filter->offset > offset + size) 8562 return false; 8563 8564 if (filter->offset + filter->size < offset) 8565 return false; 8566 8567 return true; 8568 } 8569 8570 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter, 8571 struct vm_area_struct *vma, 8572 struct perf_addr_filter_range *fr) 8573 { 8574 unsigned long vma_size = vma->vm_end - vma->vm_start; 8575 unsigned long off = vma->vm_pgoff << PAGE_SHIFT; 8576 struct file *file = vma->vm_file; 8577 8578 if (!perf_addr_filter_match(filter, file, off, vma_size)) 8579 return false; 8580 8581 if (filter->offset < off) { 8582 fr->start = vma->vm_start; 8583 fr->size = min(vma_size, filter->size - (off - filter->offset)); 8584 } else { 8585 fr->start = vma->vm_start + filter->offset - off; 8586 fr->size = min(vma->vm_end - fr->start, filter->size); 8587 } 8588 8589 return true; 8590 } 8591 8592 static void __perf_addr_filters_adjust(struct perf_event *event, void *data) 8593 { 8594 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 8595 struct vm_area_struct *vma = data; 8596 struct perf_addr_filter *filter; 8597 unsigned int restart = 0, count = 0; 8598 unsigned long flags; 8599 8600 if (!has_addr_filter(event)) 8601 return; 8602 8603 if (!vma->vm_file) 8604 return; 8605 8606 raw_spin_lock_irqsave(&ifh->lock, flags); 8607 list_for_each_entry(filter, &ifh->list, entry) { 8608 if (perf_addr_filter_vma_adjust(filter, vma, 8609 &event->addr_filter_ranges[count])) 8610 restart++; 8611 8612 count++; 8613 } 8614 8615 if (restart) 8616 event->addr_filters_gen++; 8617 raw_spin_unlock_irqrestore(&ifh->lock, flags); 8618 8619 if (restart) 8620 perf_event_stop(event, 1); 8621 } 8622 8623 /* 8624 * Adjust all task's events' filters to the new vma 8625 */ 8626 static void perf_addr_filters_adjust(struct vm_area_struct *vma) 8627 { 8628 struct perf_event_context *ctx; 8629 int ctxn; 8630 8631 /* 8632 * Data tracing isn't supported yet and as such there is no need 8633 * to keep track of anything that isn't related to executable code: 8634 */ 8635 if (!(vma->vm_flags & VM_EXEC)) 8636 return; 8637 8638 rcu_read_lock(); 8639 for_each_task_context_nr(ctxn) { 8640 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); 8641 if (!ctx) 8642 continue; 8643 8644 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true); 8645 } 8646 rcu_read_unlock(); 8647 } 8648 8649 void perf_event_mmap(struct vm_area_struct *vma) 8650 { 8651 struct perf_mmap_event mmap_event; 8652 8653 if (!atomic_read(&nr_mmap_events)) 8654 return; 8655 8656 mmap_event = (struct perf_mmap_event){ 8657 .vma = vma, 8658 /* .file_name */ 8659 /* .file_size */ 8660 .event_id = { 8661 .header = { 8662 .type = PERF_RECORD_MMAP, 8663 .misc = PERF_RECORD_MISC_USER, 8664 /* .size */ 8665 }, 8666 /* .pid */ 8667 /* .tid */ 8668 .start = vma->vm_start, 8669 .len = vma->vm_end - vma->vm_start, 8670 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT, 8671 }, 8672 /* .maj (attr_mmap2 only) */ 8673 /* .min (attr_mmap2 only) */ 8674 /* .ino (attr_mmap2 only) */ 8675 /* .ino_generation (attr_mmap2 only) */ 8676 /* .prot (attr_mmap2 only) */ 8677 /* .flags (attr_mmap2 only) */ 8678 }; 8679 8680 perf_addr_filters_adjust(vma); 8681 perf_event_mmap_event(&mmap_event); 8682 } 8683 8684 void perf_event_aux_event(struct perf_event *event, unsigned long head, 8685 unsigned long size, u64 flags) 8686 { 8687 struct perf_output_handle handle; 8688 struct perf_sample_data sample; 8689 struct perf_aux_event { 8690 struct perf_event_header header; 8691 u64 offset; 8692 u64 size; 8693 u64 flags; 8694 } rec = { 8695 .header = { 8696 .type = PERF_RECORD_AUX, 8697 .misc = 0, 8698 .size = sizeof(rec), 8699 }, 8700 .offset = head, 8701 .size = size, 8702 .flags = flags, 8703 }; 8704 int ret; 8705 8706 perf_event_header__init_id(&rec.header, &sample, event); 8707 ret = perf_output_begin(&handle, &sample, event, rec.header.size); 8708 8709 if (ret) 8710 return; 8711 8712 perf_output_put(&handle, rec); 8713 perf_event__output_id_sample(event, &handle, &sample); 8714 8715 perf_output_end(&handle); 8716 } 8717 8718 /* 8719 * Lost/dropped samples logging 8720 */ 8721 void perf_log_lost_samples(struct perf_event *event, u64 lost) 8722 { 8723 struct perf_output_handle handle; 8724 struct perf_sample_data sample; 8725 int ret; 8726 8727 struct { 8728 struct perf_event_header header; 8729 u64 lost; 8730 } lost_samples_event = { 8731 .header = { 8732 .type = PERF_RECORD_LOST_SAMPLES, 8733 .misc = 0, 8734 .size = sizeof(lost_samples_event), 8735 }, 8736 .lost = lost, 8737 }; 8738 8739 perf_event_header__init_id(&lost_samples_event.header, &sample, event); 8740 8741 ret = perf_output_begin(&handle, &sample, event, 8742 lost_samples_event.header.size); 8743 if (ret) 8744 return; 8745 8746 perf_output_put(&handle, lost_samples_event); 8747 perf_event__output_id_sample(event, &handle, &sample); 8748 perf_output_end(&handle); 8749 } 8750 8751 /* 8752 * context_switch tracking 8753 */ 8754 8755 struct perf_switch_event { 8756 struct task_struct *task; 8757 struct task_struct *next_prev; 8758 8759 struct { 8760 struct perf_event_header header; 8761 u32 next_prev_pid; 8762 u32 next_prev_tid; 8763 } event_id; 8764 }; 8765 8766 static int perf_event_switch_match(struct perf_event *event) 8767 { 8768 return event->attr.context_switch; 8769 } 8770 8771 static void perf_event_switch_output(struct perf_event *event, void *data) 8772 { 8773 struct perf_switch_event *se = data; 8774 struct perf_output_handle handle; 8775 struct perf_sample_data sample; 8776 int ret; 8777 8778 if (!perf_event_switch_match(event)) 8779 return; 8780 8781 /* Only CPU-wide events are allowed to see next/prev pid/tid */ 8782 if (event->ctx->task) { 8783 se->event_id.header.type = PERF_RECORD_SWITCH; 8784 se->event_id.header.size = sizeof(se->event_id.header); 8785 } else { 8786 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE; 8787 se->event_id.header.size = sizeof(se->event_id); 8788 se->event_id.next_prev_pid = 8789 perf_event_pid(event, se->next_prev); 8790 se->event_id.next_prev_tid = 8791 perf_event_tid(event, se->next_prev); 8792 } 8793 8794 perf_event_header__init_id(&se->event_id.header, &sample, event); 8795 8796 ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size); 8797 if (ret) 8798 return; 8799 8800 if (event->ctx->task) 8801 perf_output_put(&handle, se->event_id.header); 8802 else 8803 perf_output_put(&handle, se->event_id); 8804 8805 perf_event__output_id_sample(event, &handle, &sample); 8806 8807 perf_output_end(&handle); 8808 } 8809 8810 static void perf_event_switch(struct task_struct *task, 8811 struct task_struct *next_prev, bool sched_in) 8812 { 8813 struct perf_switch_event switch_event; 8814 8815 /* N.B. caller checks nr_switch_events != 0 */ 8816 8817 switch_event = (struct perf_switch_event){ 8818 .task = task, 8819 .next_prev = next_prev, 8820 .event_id = { 8821 .header = { 8822 /* .type */ 8823 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT, 8824 /* .size */ 8825 }, 8826 /* .next_prev_pid */ 8827 /* .next_prev_tid */ 8828 }, 8829 }; 8830 8831 if (!sched_in && task->on_rq) { 8832 switch_event.event_id.header.misc |= 8833 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT; 8834 } 8835 8836 perf_iterate_sb(perf_event_switch_output, &switch_event, NULL); 8837 } 8838 8839 /* 8840 * IRQ throttle logging 8841 */ 8842 8843 static void perf_log_throttle(struct perf_event *event, int enable) 8844 { 8845 struct perf_output_handle handle; 8846 struct perf_sample_data sample; 8847 int ret; 8848 8849 struct { 8850 struct perf_event_header header; 8851 u64 time; 8852 u64 id; 8853 u64 stream_id; 8854 } throttle_event = { 8855 .header = { 8856 .type = PERF_RECORD_THROTTLE, 8857 .misc = 0, 8858 .size = sizeof(throttle_event), 8859 }, 8860 .time = perf_event_clock(event), 8861 .id = primary_event_id(event), 8862 .stream_id = event->id, 8863 }; 8864 8865 if (enable) 8866 throttle_event.header.type = PERF_RECORD_UNTHROTTLE; 8867 8868 perf_event_header__init_id(&throttle_event.header, &sample, event); 8869 8870 ret = perf_output_begin(&handle, &sample, event, 8871 throttle_event.header.size); 8872 if (ret) 8873 return; 8874 8875 perf_output_put(&handle, throttle_event); 8876 perf_event__output_id_sample(event, &handle, &sample); 8877 perf_output_end(&handle); 8878 } 8879 8880 /* 8881 * ksymbol register/unregister tracking 8882 */ 8883 8884 struct perf_ksymbol_event { 8885 const char *name; 8886 int name_len; 8887 struct { 8888 struct perf_event_header header; 8889 u64 addr; 8890 u32 len; 8891 u16 ksym_type; 8892 u16 flags; 8893 } event_id; 8894 }; 8895 8896 static int perf_event_ksymbol_match(struct perf_event *event) 8897 { 8898 return event->attr.ksymbol; 8899 } 8900 8901 static void perf_event_ksymbol_output(struct perf_event *event, void *data) 8902 { 8903 struct perf_ksymbol_event *ksymbol_event = data; 8904 struct perf_output_handle handle; 8905 struct perf_sample_data sample; 8906 int ret; 8907 8908 if (!perf_event_ksymbol_match(event)) 8909 return; 8910 8911 perf_event_header__init_id(&ksymbol_event->event_id.header, 8912 &sample, event); 8913 ret = perf_output_begin(&handle, &sample, event, 8914 ksymbol_event->event_id.header.size); 8915 if (ret) 8916 return; 8917 8918 perf_output_put(&handle, ksymbol_event->event_id); 8919 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len); 8920 perf_event__output_id_sample(event, &handle, &sample); 8921 8922 perf_output_end(&handle); 8923 } 8924 8925 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister, 8926 const char *sym) 8927 { 8928 struct perf_ksymbol_event ksymbol_event; 8929 char name[KSYM_NAME_LEN]; 8930 u16 flags = 0; 8931 int name_len; 8932 8933 if (!atomic_read(&nr_ksymbol_events)) 8934 return; 8935 8936 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX || 8937 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN) 8938 goto err; 8939 8940 strlcpy(name, sym, KSYM_NAME_LEN); 8941 name_len = strlen(name) + 1; 8942 while (!IS_ALIGNED(name_len, sizeof(u64))) 8943 name[name_len++] = '\0'; 8944 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64)); 8945 8946 if (unregister) 8947 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER; 8948 8949 ksymbol_event = (struct perf_ksymbol_event){ 8950 .name = name, 8951 .name_len = name_len, 8952 .event_id = { 8953 .header = { 8954 .type = PERF_RECORD_KSYMBOL, 8955 .size = sizeof(ksymbol_event.event_id) + 8956 name_len, 8957 }, 8958 .addr = addr, 8959 .len = len, 8960 .ksym_type = ksym_type, 8961 .flags = flags, 8962 }, 8963 }; 8964 8965 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL); 8966 return; 8967 err: 8968 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type); 8969 } 8970 8971 /* 8972 * bpf program load/unload tracking 8973 */ 8974 8975 struct perf_bpf_event { 8976 struct bpf_prog *prog; 8977 struct { 8978 struct perf_event_header header; 8979 u16 type; 8980 u16 flags; 8981 u32 id; 8982 u8 tag[BPF_TAG_SIZE]; 8983 } event_id; 8984 }; 8985 8986 static int perf_event_bpf_match(struct perf_event *event) 8987 { 8988 return event->attr.bpf_event; 8989 } 8990 8991 static void perf_event_bpf_output(struct perf_event *event, void *data) 8992 { 8993 struct perf_bpf_event *bpf_event = data; 8994 struct perf_output_handle handle; 8995 struct perf_sample_data sample; 8996 int ret; 8997 8998 if (!perf_event_bpf_match(event)) 8999 return; 9000 9001 perf_event_header__init_id(&bpf_event->event_id.header, 9002 &sample, event); 9003 ret = perf_output_begin(&handle, data, event, 9004 bpf_event->event_id.header.size); 9005 if (ret) 9006 return; 9007 9008 perf_output_put(&handle, bpf_event->event_id); 9009 perf_event__output_id_sample(event, &handle, &sample); 9010 9011 perf_output_end(&handle); 9012 } 9013 9014 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog, 9015 enum perf_bpf_event_type type) 9016 { 9017 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD; 9018 int i; 9019 9020 if (prog->aux->func_cnt == 0) { 9021 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF, 9022 (u64)(unsigned long)prog->bpf_func, 9023 prog->jited_len, unregister, 9024 prog->aux->ksym.name); 9025 } else { 9026 for (i = 0; i < prog->aux->func_cnt; i++) { 9027 struct bpf_prog *subprog = prog->aux->func[i]; 9028 9029 perf_event_ksymbol( 9030 PERF_RECORD_KSYMBOL_TYPE_BPF, 9031 (u64)(unsigned long)subprog->bpf_func, 9032 subprog->jited_len, unregister, 9033 prog->aux->ksym.name); 9034 } 9035 } 9036 } 9037 9038 void perf_event_bpf_event(struct bpf_prog *prog, 9039 enum perf_bpf_event_type type, 9040 u16 flags) 9041 { 9042 struct perf_bpf_event bpf_event; 9043 9044 if (type <= PERF_BPF_EVENT_UNKNOWN || 9045 type >= PERF_BPF_EVENT_MAX) 9046 return; 9047 9048 switch (type) { 9049 case PERF_BPF_EVENT_PROG_LOAD: 9050 case PERF_BPF_EVENT_PROG_UNLOAD: 9051 if (atomic_read(&nr_ksymbol_events)) 9052 perf_event_bpf_emit_ksymbols(prog, type); 9053 break; 9054 default: 9055 break; 9056 } 9057 9058 if (!atomic_read(&nr_bpf_events)) 9059 return; 9060 9061 bpf_event = (struct perf_bpf_event){ 9062 .prog = prog, 9063 .event_id = { 9064 .header = { 9065 .type = PERF_RECORD_BPF_EVENT, 9066 .size = sizeof(bpf_event.event_id), 9067 }, 9068 .type = type, 9069 .flags = flags, 9070 .id = prog->aux->id, 9071 }, 9072 }; 9073 9074 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64)); 9075 9076 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE); 9077 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL); 9078 } 9079 9080 struct perf_text_poke_event { 9081 const void *old_bytes; 9082 const void *new_bytes; 9083 size_t pad; 9084 u16 old_len; 9085 u16 new_len; 9086 9087 struct { 9088 struct perf_event_header header; 9089 9090 u64 addr; 9091 } event_id; 9092 }; 9093 9094 static int perf_event_text_poke_match(struct perf_event *event) 9095 { 9096 return event->attr.text_poke; 9097 } 9098 9099 static void perf_event_text_poke_output(struct perf_event *event, void *data) 9100 { 9101 struct perf_text_poke_event *text_poke_event = data; 9102 struct perf_output_handle handle; 9103 struct perf_sample_data sample; 9104 u64 padding = 0; 9105 int ret; 9106 9107 if (!perf_event_text_poke_match(event)) 9108 return; 9109 9110 perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event); 9111 9112 ret = perf_output_begin(&handle, &sample, event, 9113 text_poke_event->event_id.header.size); 9114 if (ret) 9115 return; 9116 9117 perf_output_put(&handle, text_poke_event->event_id); 9118 perf_output_put(&handle, text_poke_event->old_len); 9119 perf_output_put(&handle, text_poke_event->new_len); 9120 9121 __output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len); 9122 __output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len); 9123 9124 if (text_poke_event->pad) 9125 __output_copy(&handle, &padding, text_poke_event->pad); 9126 9127 perf_event__output_id_sample(event, &handle, &sample); 9128 9129 perf_output_end(&handle); 9130 } 9131 9132 void perf_event_text_poke(const void *addr, const void *old_bytes, 9133 size_t old_len, const void *new_bytes, size_t new_len) 9134 { 9135 struct perf_text_poke_event text_poke_event; 9136 size_t tot, pad; 9137 9138 if (!atomic_read(&nr_text_poke_events)) 9139 return; 9140 9141 tot = sizeof(text_poke_event.old_len) + old_len; 9142 tot += sizeof(text_poke_event.new_len) + new_len; 9143 pad = ALIGN(tot, sizeof(u64)) - tot; 9144 9145 text_poke_event = (struct perf_text_poke_event){ 9146 .old_bytes = old_bytes, 9147 .new_bytes = new_bytes, 9148 .pad = pad, 9149 .old_len = old_len, 9150 .new_len = new_len, 9151 .event_id = { 9152 .header = { 9153 .type = PERF_RECORD_TEXT_POKE, 9154 .misc = PERF_RECORD_MISC_KERNEL, 9155 .size = sizeof(text_poke_event.event_id) + tot + pad, 9156 }, 9157 .addr = (unsigned long)addr, 9158 }, 9159 }; 9160 9161 perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL); 9162 } 9163 9164 void perf_event_itrace_started(struct perf_event *event) 9165 { 9166 event->attach_state |= PERF_ATTACH_ITRACE; 9167 } 9168 9169 static void perf_log_itrace_start(struct perf_event *event) 9170 { 9171 struct perf_output_handle handle; 9172 struct perf_sample_data sample; 9173 struct perf_aux_event { 9174 struct perf_event_header header; 9175 u32 pid; 9176 u32 tid; 9177 } rec; 9178 int ret; 9179 9180 if (event->parent) 9181 event = event->parent; 9182 9183 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) || 9184 event->attach_state & PERF_ATTACH_ITRACE) 9185 return; 9186 9187 rec.header.type = PERF_RECORD_ITRACE_START; 9188 rec.header.misc = 0; 9189 rec.header.size = sizeof(rec); 9190 rec.pid = perf_event_pid(event, current); 9191 rec.tid = perf_event_tid(event, current); 9192 9193 perf_event_header__init_id(&rec.header, &sample, event); 9194 ret = perf_output_begin(&handle, &sample, event, rec.header.size); 9195 9196 if (ret) 9197 return; 9198 9199 perf_output_put(&handle, rec); 9200 perf_event__output_id_sample(event, &handle, &sample); 9201 9202 perf_output_end(&handle); 9203 } 9204 9205 void perf_report_aux_output_id(struct perf_event *event, u64 hw_id) 9206 { 9207 struct perf_output_handle handle; 9208 struct perf_sample_data sample; 9209 struct perf_aux_event { 9210 struct perf_event_header header; 9211 u64 hw_id; 9212 } rec; 9213 int ret; 9214 9215 if (event->parent) 9216 event = event->parent; 9217 9218 rec.header.type = PERF_RECORD_AUX_OUTPUT_HW_ID; 9219 rec.header.misc = 0; 9220 rec.header.size = sizeof(rec); 9221 rec.hw_id = hw_id; 9222 9223 perf_event_header__init_id(&rec.header, &sample, event); 9224 ret = perf_output_begin(&handle, &sample, event, rec.header.size); 9225 9226 if (ret) 9227 return; 9228 9229 perf_output_put(&handle, rec); 9230 perf_event__output_id_sample(event, &handle, &sample); 9231 9232 perf_output_end(&handle); 9233 } 9234 9235 static int 9236 __perf_event_account_interrupt(struct perf_event *event, int throttle) 9237 { 9238 struct hw_perf_event *hwc = &event->hw; 9239 int ret = 0; 9240 u64 seq; 9241 9242 seq = __this_cpu_read(perf_throttled_seq); 9243 if (seq != hwc->interrupts_seq) { 9244 hwc->interrupts_seq = seq; 9245 hwc->interrupts = 1; 9246 } else { 9247 hwc->interrupts++; 9248 if (unlikely(throttle 9249 && hwc->interrupts >= max_samples_per_tick)) { 9250 __this_cpu_inc(perf_throttled_count); 9251 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS); 9252 hwc->interrupts = MAX_INTERRUPTS; 9253 perf_log_throttle(event, 0); 9254 ret = 1; 9255 } 9256 } 9257 9258 if (event->attr.freq) { 9259 u64 now = perf_clock(); 9260 s64 delta = now - hwc->freq_time_stamp; 9261 9262 hwc->freq_time_stamp = now; 9263 9264 if (delta > 0 && delta < 2*TICK_NSEC) 9265 perf_adjust_period(event, delta, hwc->last_period, true); 9266 } 9267 9268 return ret; 9269 } 9270 9271 int perf_event_account_interrupt(struct perf_event *event) 9272 { 9273 return __perf_event_account_interrupt(event, 1); 9274 } 9275 9276 /* 9277 * Generic event overflow handling, sampling. 9278 */ 9279 9280 static int __perf_event_overflow(struct perf_event *event, 9281 int throttle, struct perf_sample_data *data, 9282 struct pt_regs *regs) 9283 { 9284 int events = atomic_read(&event->event_limit); 9285 int ret = 0; 9286 9287 /* 9288 * Non-sampling counters might still use the PMI to fold short 9289 * hardware counters, ignore those. 9290 */ 9291 if (unlikely(!is_sampling_event(event))) 9292 return 0; 9293 9294 ret = __perf_event_account_interrupt(event, throttle); 9295 9296 /* 9297 * XXX event_limit might not quite work as expected on inherited 9298 * events 9299 */ 9300 9301 event->pending_kill = POLL_IN; 9302 if (events && atomic_dec_and_test(&event->event_limit)) { 9303 ret = 1; 9304 event->pending_kill = POLL_HUP; 9305 perf_event_disable_inatomic(event); 9306 } 9307 9308 if (event->attr.sigtrap) { 9309 /* 9310 * Should not be able to return to user space without processing 9311 * pending_sigtrap (kernel events can overflow multiple times). 9312 */ 9313 WARN_ON_ONCE(event->pending_sigtrap && event->attr.exclude_kernel); 9314 if (!event->pending_sigtrap) { 9315 event->pending_sigtrap = 1; 9316 local_inc(&event->ctx->nr_pending); 9317 } 9318 event->pending_addr = data->addr; 9319 irq_work_queue(&event->pending_irq); 9320 } 9321 9322 READ_ONCE(event->overflow_handler)(event, data, regs); 9323 9324 if (*perf_event_fasync(event) && event->pending_kill) { 9325 event->pending_wakeup = 1; 9326 irq_work_queue(&event->pending_irq); 9327 } 9328 9329 return ret; 9330 } 9331 9332 int perf_event_overflow(struct perf_event *event, 9333 struct perf_sample_data *data, 9334 struct pt_regs *regs) 9335 { 9336 return __perf_event_overflow(event, 1, data, regs); 9337 } 9338 9339 /* 9340 * Generic software event infrastructure 9341 */ 9342 9343 struct swevent_htable { 9344 struct swevent_hlist *swevent_hlist; 9345 struct mutex hlist_mutex; 9346 int hlist_refcount; 9347 9348 /* Recursion avoidance in each contexts */ 9349 int recursion[PERF_NR_CONTEXTS]; 9350 }; 9351 9352 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable); 9353 9354 /* 9355 * We directly increment event->count and keep a second value in 9356 * event->hw.period_left to count intervals. This period event 9357 * is kept in the range [-sample_period, 0] so that we can use the 9358 * sign as trigger. 9359 */ 9360 9361 u64 perf_swevent_set_period(struct perf_event *event) 9362 { 9363 struct hw_perf_event *hwc = &event->hw; 9364 u64 period = hwc->last_period; 9365 u64 nr, offset; 9366 s64 old, val; 9367 9368 hwc->last_period = hwc->sample_period; 9369 9370 again: 9371 old = val = local64_read(&hwc->period_left); 9372 if (val < 0) 9373 return 0; 9374 9375 nr = div64_u64(period + val, period); 9376 offset = nr * period; 9377 val -= offset; 9378 if (local64_cmpxchg(&hwc->period_left, old, val) != old) 9379 goto again; 9380 9381 return nr; 9382 } 9383 9384 static void perf_swevent_overflow(struct perf_event *event, u64 overflow, 9385 struct perf_sample_data *data, 9386 struct pt_regs *regs) 9387 { 9388 struct hw_perf_event *hwc = &event->hw; 9389 int throttle = 0; 9390 9391 if (!overflow) 9392 overflow = perf_swevent_set_period(event); 9393 9394 if (hwc->interrupts == MAX_INTERRUPTS) 9395 return; 9396 9397 for (; overflow; overflow--) { 9398 if (__perf_event_overflow(event, throttle, 9399 data, regs)) { 9400 /* 9401 * We inhibit the overflow from happening when 9402 * hwc->interrupts == MAX_INTERRUPTS. 9403 */ 9404 break; 9405 } 9406 throttle = 1; 9407 } 9408 } 9409 9410 static void perf_swevent_event(struct perf_event *event, u64 nr, 9411 struct perf_sample_data *data, 9412 struct pt_regs *regs) 9413 { 9414 struct hw_perf_event *hwc = &event->hw; 9415 9416 local64_add(nr, &event->count); 9417 9418 if (!regs) 9419 return; 9420 9421 if (!is_sampling_event(event)) 9422 return; 9423 9424 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) { 9425 data->period = nr; 9426 return perf_swevent_overflow(event, 1, data, regs); 9427 } else 9428 data->period = event->hw.last_period; 9429 9430 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq) 9431 return perf_swevent_overflow(event, 1, data, regs); 9432 9433 if (local64_add_negative(nr, &hwc->period_left)) 9434 return; 9435 9436 perf_swevent_overflow(event, 0, data, regs); 9437 } 9438 9439 static int perf_exclude_event(struct perf_event *event, 9440 struct pt_regs *regs) 9441 { 9442 if (event->hw.state & PERF_HES_STOPPED) 9443 return 1; 9444 9445 if (regs) { 9446 if (event->attr.exclude_user && user_mode(regs)) 9447 return 1; 9448 9449 if (event->attr.exclude_kernel && !user_mode(regs)) 9450 return 1; 9451 } 9452 9453 return 0; 9454 } 9455 9456 static int perf_swevent_match(struct perf_event *event, 9457 enum perf_type_id type, 9458 u32 event_id, 9459 struct perf_sample_data *data, 9460 struct pt_regs *regs) 9461 { 9462 if (event->attr.type != type) 9463 return 0; 9464 9465 if (event->attr.config != event_id) 9466 return 0; 9467 9468 if (perf_exclude_event(event, regs)) 9469 return 0; 9470 9471 return 1; 9472 } 9473 9474 static inline u64 swevent_hash(u64 type, u32 event_id) 9475 { 9476 u64 val = event_id | (type << 32); 9477 9478 return hash_64(val, SWEVENT_HLIST_BITS); 9479 } 9480 9481 static inline struct hlist_head * 9482 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id) 9483 { 9484 u64 hash = swevent_hash(type, event_id); 9485 9486 return &hlist->heads[hash]; 9487 } 9488 9489 /* For the read side: events when they trigger */ 9490 static inline struct hlist_head * 9491 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id) 9492 { 9493 struct swevent_hlist *hlist; 9494 9495 hlist = rcu_dereference(swhash->swevent_hlist); 9496 if (!hlist) 9497 return NULL; 9498 9499 return __find_swevent_head(hlist, type, event_id); 9500 } 9501 9502 /* For the event head insertion and removal in the hlist */ 9503 static inline struct hlist_head * 9504 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event) 9505 { 9506 struct swevent_hlist *hlist; 9507 u32 event_id = event->attr.config; 9508 u64 type = event->attr.type; 9509 9510 /* 9511 * Event scheduling is always serialized against hlist allocation 9512 * and release. Which makes the protected version suitable here. 9513 * The context lock guarantees that. 9514 */ 9515 hlist = rcu_dereference_protected(swhash->swevent_hlist, 9516 lockdep_is_held(&event->ctx->lock)); 9517 if (!hlist) 9518 return NULL; 9519 9520 return __find_swevent_head(hlist, type, event_id); 9521 } 9522 9523 static void do_perf_sw_event(enum perf_type_id type, u32 event_id, 9524 u64 nr, 9525 struct perf_sample_data *data, 9526 struct pt_regs *regs) 9527 { 9528 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 9529 struct perf_event *event; 9530 struct hlist_head *head; 9531 9532 rcu_read_lock(); 9533 head = find_swevent_head_rcu(swhash, type, event_id); 9534 if (!head) 9535 goto end; 9536 9537 hlist_for_each_entry_rcu(event, head, hlist_entry) { 9538 if (perf_swevent_match(event, type, event_id, data, regs)) 9539 perf_swevent_event(event, nr, data, regs); 9540 } 9541 end: 9542 rcu_read_unlock(); 9543 } 9544 9545 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]); 9546 9547 int perf_swevent_get_recursion_context(void) 9548 { 9549 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 9550 9551 return get_recursion_context(swhash->recursion); 9552 } 9553 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context); 9554 9555 void perf_swevent_put_recursion_context(int rctx) 9556 { 9557 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 9558 9559 put_recursion_context(swhash->recursion, rctx); 9560 } 9561 9562 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) 9563 { 9564 struct perf_sample_data data; 9565 9566 if (WARN_ON_ONCE(!regs)) 9567 return; 9568 9569 perf_sample_data_init(&data, addr, 0); 9570 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs); 9571 } 9572 9573 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) 9574 { 9575 int rctx; 9576 9577 preempt_disable_notrace(); 9578 rctx = perf_swevent_get_recursion_context(); 9579 if (unlikely(rctx < 0)) 9580 goto fail; 9581 9582 ___perf_sw_event(event_id, nr, regs, addr); 9583 9584 perf_swevent_put_recursion_context(rctx); 9585 fail: 9586 preempt_enable_notrace(); 9587 } 9588 9589 static void perf_swevent_read(struct perf_event *event) 9590 { 9591 } 9592 9593 static int perf_swevent_add(struct perf_event *event, int flags) 9594 { 9595 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable); 9596 struct hw_perf_event *hwc = &event->hw; 9597 struct hlist_head *head; 9598 9599 if (is_sampling_event(event)) { 9600 hwc->last_period = hwc->sample_period; 9601 perf_swevent_set_period(event); 9602 } 9603 9604 hwc->state = !(flags & PERF_EF_START); 9605 9606 head = find_swevent_head(swhash, event); 9607 if (WARN_ON_ONCE(!head)) 9608 return -EINVAL; 9609 9610 hlist_add_head_rcu(&event->hlist_entry, head); 9611 perf_event_update_userpage(event); 9612 9613 return 0; 9614 } 9615 9616 static void perf_swevent_del(struct perf_event *event, int flags) 9617 { 9618 hlist_del_rcu(&event->hlist_entry); 9619 } 9620 9621 static void perf_swevent_start(struct perf_event *event, int flags) 9622 { 9623 event->hw.state = 0; 9624 } 9625 9626 static void perf_swevent_stop(struct perf_event *event, int flags) 9627 { 9628 event->hw.state = PERF_HES_STOPPED; 9629 } 9630 9631 /* Deref the hlist from the update side */ 9632 static inline struct swevent_hlist * 9633 swevent_hlist_deref(struct swevent_htable *swhash) 9634 { 9635 return rcu_dereference_protected(swhash->swevent_hlist, 9636 lockdep_is_held(&swhash->hlist_mutex)); 9637 } 9638 9639 static void swevent_hlist_release(struct swevent_htable *swhash) 9640 { 9641 struct swevent_hlist *hlist = swevent_hlist_deref(swhash); 9642 9643 if (!hlist) 9644 return; 9645 9646 RCU_INIT_POINTER(swhash->swevent_hlist, NULL); 9647 kfree_rcu(hlist, rcu_head); 9648 } 9649 9650 static void swevent_hlist_put_cpu(int cpu) 9651 { 9652 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 9653 9654 mutex_lock(&swhash->hlist_mutex); 9655 9656 if (!--swhash->hlist_refcount) 9657 swevent_hlist_release(swhash); 9658 9659 mutex_unlock(&swhash->hlist_mutex); 9660 } 9661 9662 static void swevent_hlist_put(void) 9663 { 9664 int cpu; 9665 9666 for_each_possible_cpu(cpu) 9667 swevent_hlist_put_cpu(cpu); 9668 } 9669 9670 static int swevent_hlist_get_cpu(int cpu) 9671 { 9672 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 9673 int err = 0; 9674 9675 mutex_lock(&swhash->hlist_mutex); 9676 if (!swevent_hlist_deref(swhash) && 9677 cpumask_test_cpu(cpu, perf_online_mask)) { 9678 struct swevent_hlist *hlist; 9679 9680 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL); 9681 if (!hlist) { 9682 err = -ENOMEM; 9683 goto exit; 9684 } 9685 rcu_assign_pointer(swhash->swevent_hlist, hlist); 9686 } 9687 swhash->hlist_refcount++; 9688 exit: 9689 mutex_unlock(&swhash->hlist_mutex); 9690 9691 return err; 9692 } 9693 9694 static int swevent_hlist_get(void) 9695 { 9696 int err, cpu, failed_cpu; 9697 9698 mutex_lock(&pmus_lock); 9699 for_each_possible_cpu(cpu) { 9700 err = swevent_hlist_get_cpu(cpu); 9701 if (err) { 9702 failed_cpu = cpu; 9703 goto fail; 9704 } 9705 } 9706 mutex_unlock(&pmus_lock); 9707 return 0; 9708 fail: 9709 for_each_possible_cpu(cpu) { 9710 if (cpu == failed_cpu) 9711 break; 9712 swevent_hlist_put_cpu(cpu); 9713 } 9714 mutex_unlock(&pmus_lock); 9715 return err; 9716 } 9717 9718 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX]; 9719 9720 static void sw_perf_event_destroy(struct perf_event *event) 9721 { 9722 u64 event_id = event->attr.config; 9723 9724 WARN_ON(event->parent); 9725 9726 static_key_slow_dec(&perf_swevent_enabled[event_id]); 9727 swevent_hlist_put(); 9728 } 9729 9730 static int perf_swevent_init(struct perf_event *event) 9731 { 9732 u64 event_id = event->attr.config; 9733 9734 if (event->attr.type != PERF_TYPE_SOFTWARE) 9735 return -ENOENT; 9736 9737 /* 9738 * no branch sampling for software events 9739 */ 9740 if (has_branch_stack(event)) 9741 return -EOPNOTSUPP; 9742 9743 switch (event_id) { 9744 case PERF_COUNT_SW_CPU_CLOCK: 9745 case PERF_COUNT_SW_TASK_CLOCK: 9746 return -ENOENT; 9747 9748 default: 9749 break; 9750 } 9751 9752 if (event_id >= PERF_COUNT_SW_MAX) 9753 return -ENOENT; 9754 9755 if (!event->parent) { 9756 int err; 9757 9758 err = swevent_hlist_get(); 9759 if (err) 9760 return err; 9761 9762 static_key_slow_inc(&perf_swevent_enabled[event_id]); 9763 event->destroy = sw_perf_event_destroy; 9764 } 9765 9766 return 0; 9767 } 9768 9769 static struct pmu perf_swevent = { 9770 .task_ctx_nr = perf_sw_context, 9771 9772 .capabilities = PERF_PMU_CAP_NO_NMI, 9773 9774 .event_init = perf_swevent_init, 9775 .add = perf_swevent_add, 9776 .del = perf_swevent_del, 9777 .start = perf_swevent_start, 9778 .stop = perf_swevent_stop, 9779 .read = perf_swevent_read, 9780 }; 9781 9782 #ifdef CONFIG_EVENT_TRACING 9783 9784 static int perf_tp_filter_match(struct perf_event *event, 9785 struct perf_sample_data *data) 9786 { 9787 void *record = data->raw->frag.data; 9788 9789 /* only top level events have filters set */ 9790 if (event->parent) 9791 event = event->parent; 9792 9793 if (likely(!event->filter) || filter_match_preds(event->filter, record)) 9794 return 1; 9795 return 0; 9796 } 9797 9798 static int perf_tp_event_match(struct perf_event *event, 9799 struct perf_sample_data *data, 9800 struct pt_regs *regs) 9801 { 9802 if (event->hw.state & PERF_HES_STOPPED) 9803 return 0; 9804 /* 9805 * If exclude_kernel, only trace user-space tracepoints (uprobes) 9806 */ 9807 if (event->attr.exclude_kernel && !user_mode(regs)) 9808 return 0; 9809 9810 if (!perf_tp_filter_match(event, data)) 9811 return 0; 9812 9813 return 1; 9814 } 9815 9816 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx, 9817 struct trace_event_call *call, u64 count, 9818 struct pt_regs *regs, struct hlist_head *head, 9819 struct task_struct *task) 9820 { 9821 if (bpf_prog_array_valid(call)) { 9822 *(struct pt_regs **)raw_data = regs; 9823 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) { 9824 perf_swevent_put_recursion_context(rctx); 9825 return; 9826 } 9827 } 9828 perf_tp_event(call->event.type, count, raw_data, size, regs, head, 9829 rctx, task); 9830 } 9831 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit); 9832 9833 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size, 9834 struct pt_regs *regs, struct hlist_head *head, int rctx, 9835 struct task_struct *task) 9836 { 9837 struct perf_sample_data data; 9838 struct perf_event *event; 9839 9840 struct perf_raw_record raw = { 9841 .frag = { 9842 .size = entry_size, 9843 .data = record, 9844 }, 9845 }; 9846 9847 perf_sample_data_init(&data, 0, 0); 9848 data.raw = &raw; 9849 data.sample_flags |= PERF_SAMPLE_RAW; 9850 9851 perf_trace_buf_update(record, event_type); 9852 9853 hlist_for_each_entry_rcu(event, head, hlist_entry) { 9854 if (perf_tp_event_match(event, &data, regs)) 9855 perf_swevent_event(event, count, &data, regs); 9856 } 9857 9858 /* 9859 * If we got specified a target task, also iterate its context and 9860 * deliver this event there too. 9861 */ 9862 if (task && task != current) { 9863 struct perf_event_context *ctx; 9864 struct trace_entry *entry = record; 9865 9866 rcu_read_lock(); 9867 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]); 9868 if (!ctx) 9869 goto unlock; 9870 9871 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) { 9872 if (event->cpu != smp_processor_id()) 9873 continue; 9874 if (event->attr.type != PERF_TYPE_TRACEPOINT) 9875 continue; 9876 if (event->attr.config != entry->type) 9877 continue; 9878 /* Cannot deliver synchronous signal to other task. */ 9879 if (event->attr.sigtrap) 9880 continue; 9881 if (perf_tp_event_match(event, &data, regs)) 9882 perf_swevent_event(event, count, &data, regs); 9883 } 9884 unlock: 9885 rcu_read_unlock(); 9886 } 9887 9888 perf_swevent_put_recursion_context(rctx); 9889 } 9890 EXPORT_SYMBOL_GPL(perf_tp_event); 9891 9892 static void tp_perf_event_destroy(struct perf_event *event) 9893 { 9894 perf_trace_destroy(event); 9895 } 9896 9897 static int perf_tp_event_init(struct perf_event *event) 9898 { 9899 int err; 9900 9901 if (event->attr.type != PERF_TYPE_TRACEPOINT) 9902 return -ENOENT; 9903 9904 /* 9905 * no branch sampling for tracepoint events 9906 */ 9907 if (has_branch_stack(event)) 9908 return -EOPNOTSUPP; 9909 9910 err = perf_trace_init(event); 9911 if (err) 9912 return err; 9913 9914 event->destroy = tp_perf_event_destroy; 9915 9916 return 0; 9917 } 9918 9919 static struct pmu perf_tracepoint = { 9920 .task_ctx_nr = perf_sw_context, 9921 9922 .event_init = perf_tp_event_init, 9923 .add = perf_trace_add, 9924 .del = perf_trace_del, 9925 .start = perf_swevent_start, 9926 .stop = perf_swevent_stop, 9927 .read = perf_swevent_read, 9928 }; 9929 9930 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS) 9931 /* 9932 * Flags in config, used by dynamic PMU kprobe and uprobe 9933 * The flags should match following PMU_FORMAT_ATTR(). 9934 * 9935 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe 9936 * if not set, create kprobe/uprobe 9937 * 9938 * The following values specify a reference counter (or semaphore in the 9939 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically 9940 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset. 9941 * 9942 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset 9943 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left 9944 */ 9945 enum perf_probe_config { 9946 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */ 9947 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32, 9948 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS, 9949 }; 9950 9951 PMU_FORMAT_ATTR(retprobe, "config:0"); 9952 #endif 9953 9954 #ifdef CONFIG_KPROBE_EVENTS 9955 static struct attribute *kprobe_attrs[] = { 9956 &format_attr_retprobe.attr, 9957 NULL, 9958 }; 9959 9960 static struct attribute_group kprobe_format_group = { 9961 .name = "format", 9962 .attrs = kprobe_attrs, 9963 }; 9964 9965 static const struct attribute_group *kprobe_attr_groups[] = { 9966 &kprobe_format_group, 9967 NULL, 9968 }; 9969 9970 static int perf_kprobe_event_init(struct perf_event *event); 9971 static struct pmu perf_kprobe = { 9972 .task_ctx_nr = perf_sw_context, 9973 .event_init = perf_kprobe_event_init, 9974 .add = perf_trace_add, 9975 .del = perf_trace_del, 9976 .start = perf_swevent_start, 9977 .stop = perf_swevent_stop, 9978 .read = perf_swevent_read, 9979 .attr_groups = kprobe_attr_groups, 9980 }; 9981 9982 static int perf_kprobe_event_init(struct perf_event *event) 9983 { 9984 int err; 9985 bool is_retprobe; 9986 9987 if (event->attr.type != perf_kprobe.type) 9988 return -ENOENT; 9989 9990 if (!perfmon_capable()) 9991 return -EACCES; 9992 9993 /* 9994 * no branch sampling for probe events 9995 */ 9996 if (has_branch_stack(event)) 9997 return -EOPNOTSUPP; 9998 9999 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE; 10000 err = perf_kprobe_init(event, is_retprobe); 10001 if (err) 10002 return err; 10003 10004 event->destroy = perf_kprobe_destroy; 10005 10006 return 0; 10007 } 10008 #endif /* CONFIG_KPROBE_EVENTS */ 10009 10010 #ifdef CONFIG_UPROBE_EVENTS 10011 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63"); 10012 10013 static struct attribute *uprobe_attrs[] = { 10014 &format_attr_retprobe.attr, 10015 &format_attr_ref_ctr_offset.attr, 10016 NULL, 10017 }; 10018 10019 static struct attribute_group uprobe_format_group = { 10020 .name = "format", 10021 .attrs = uprobe_attrs, 10022 }; 10023 10024 static const struct attribute_group *uprobe_attr_groups[] = { 10025 &uprobe_format_group, 10026 NULL, 10027 }; 10028 10029 static int perf_uprobe_event_init(struct perf_event *event); 10030 static struct pmu perf_uprobe = { 10031 .task_ctx_nr = perf_sw_context, 10032 .event_init = perf_uprobe_event_init, 10033 .add = perf_trace_add, 10034 .del = perf_trace_del, 10035 .start = perf_swevent_start, 10036 .stop = perf_swevent_stop, 10037 .read = perf_swevent_read, 10038 .attr_groups = uprobe_attr_groups, 10039 }; 10040 10041 static int perf_uprobe_event_init(struct perf_event *event) 10042 { 10043 int err; 10044 unsigned long ref_ctr_offset; 10045 bool is_retprobe; 10046 10047 if (event->attr.type != perf_uprobe.type) 10048 return -ENOENT; 10049 10050 if (!perfmon_capable()) 10051 return -EACCES; 10052 10053 /* 10054 * no branch sampling for probe events 10055 */ 10056 if (has_branch_stack(event)) 10057 return -EOPNOTSUPP; 10058 10059 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE; 10060 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT; 10061 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe); 10062 if (err) 10063 return err; 10064 10065 event->destroy = perf_uprobe_destroy; 10066 10067 return 0; 10068 } 10069 #endif /* CONFIG_UPROBE_EVENTS */ 10070 10071 static inline void perf_tp_register(void) 10072 { 10073 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT); 10074 #ifdef CONFIG_KPROBE_EVENTS 10075 perf_pmu_register(&perf_kprobe, "kprobe", -1); 10076 #endif 10077 #ifdef CONFIG_UPROBE_EVENTS 10078 perf_pmu_register(&perf_uprobe, "uprobe", -1); 10079 #endif 10080 } 10081 10082 static void perf_event_free_filter(struct perf_event *event) 10083 { 10084 ftrace_profile_free_filter(event); 10085 } 10086 10087 #ifdef CONFIG_BPF_SYSCALL 10088 static void bpf_overflow_handler(struct perf_event *event, 10089 struct perf_sample_data *data, 10090 struct pt_regs *regs) 10091 { 10092 struct bpf_perf_event_data_kern ctx = { 10093 .data = data, 10094 .event = event, 10095 }; 10096 struct bpf_prog *prog; 10097 int ret = 0; 10098 10099 ctx.regs = perf_arch_bpf_user_pt_regs(regs); 10100 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) 10101 goto out; 10102 rcu_read_lock(); 10103 prog = READ_ONCE(event->prog); 10104 if (prog) { 10105 if (prog->call_get_stack && 10106 (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) && 10107 !(data->sample_flags & PERF_SAMPLE_CALLCHAIN)) { 10108 data->callchain = perf_callchain(event, regs); 10109 data->sample_flags |= PERF_SAMPLE_CALLCHAIN; 10110 } 10111 10112 ret = bpf_prog_run(prog, &ctx); 10113 } 10114 rcu_read_unlock(); 10115 out: 10116 __this_cpu_dec(bpf_prog_active); 10117 if (!ret) 10118 return; 10119 10120 event->orig_overflow_handler(event, data, regs); 10121 } 10122 10123 static int perf_event_set_bpf_handler(struct perf_event *event, 10124 struct bpf_prog *prog, 10125 u64 bpf_cookie) 10126 { 10127 if (event->overflow_handler_context) 10128 /* hw breakpoint or kernel counter */ 10129 return -EINVAL; 10130 10131 if (event->prog) 10132 return -EEXIST; 10133 10134 if (prog->type != BPF_PROG_TYPE_PERF_EVENT) 10135 return -EINVAL; 10136 10137 if (event->attr.precise_ip && 10138 prog->call_get_stack && 10139 (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) || 10140 event->attr.exclude_callchain_kernel || 10141 event->attr.exclude_callchain_user)) { 10142 /* 10143 * On perf_event with precise_ip, calling bpf_get_stack() 10144 * may trigger unwinder warnings and occasional crashes. 10145 * bpf_get_[stack|stackid] works around this issue by using 10146 * callchain attached to perf_sample_data. If the 10147 * perf_event does not full (kernel and user) callchain 10148 * attached to perf_sample_data, do not allow attaching BPF 10149 * program that calls bpf_get_[stack|stackid]. 10150 */ 10151 return -EPROTO; 10152 } 10153 10154 event->prog = prog; 10155 event->bpf_cookie = bpf_cookie; 10156 event->orig_overflow_handler = READ_ONCE(event->overflow_handler); 10157 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler); 10158 return 0; 10159 } 10160 10161 static void perf_event_free_bpf_handler(struct perf_event *event) 10162 { 10163 struct bpf_prog *prog = event->prog; 10164 10165 if (!prog) 10166 return; 10167 10168 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler); 10169 event->prog = NULL; 10170 bpf_prog_put(prog); 10171 } 10172 #else 10173 static int perf_event_set_bpf_handler(struct perf_event *event, 10174 struct bpf_prog *prog, 10175 u64 bpf_cookie) 10176 { 10177 return -EOPNOTSUPP; 10178 } 10179 static void perf_event_free_bpf_handler(struct perf_event *event) 10180 { 10181 } 10182 #endif 10183 10184 /* 10185 * returns true if the event is a tracepoint, or a kprobe/upprobe created 10186 * with perf_event_open() 10187 */ 10188 static inline bool perf_event_is_tracing(struct perf_event *event) 10189 { 10190 if (event->pmu == &perf_tracepoint) 10191 return true; 10192 #ifdef CONFIG_KPROBE_EVENTS 10193 if (event->pmu == &perf_kprobe) 10194 return true; 10195 #endif 10196 #ifdef CONFIG_UPROBE_EVENTS 10197 if (event->pmu == &perf_uprobe) 10198 return true; 10199 #endif 10200 return false; 10201 } 10202 10203 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog, 10204 u64 bpf_cookie) 10205 { 10206 bool is_kprobe, is_uprobe, is_tracepoint, is_syscall_tp; 10207 10208 if (!perf_event_is_tracing(event)) 10209 return perf_event_set_bpf_handler(event, prog, bpf_cookie); 10210 10211 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_KPROBE; 10212 is_uprobe = event->tp_event->flags & TRACE_EVENT_FL_UPROBE; 10213 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT; 10214 is_syscall_tp = is_syscall_trace_event(event->tp_event); 10215 if (!is_kprobe && !is_uprobe && !is_tracepoint && !is_syscall_tp) 10216 /* bpf programs can only be attached to u/kprobe or tracepoint */ 10217 return -EINVAL; 10218 10219 if (((is_kprobe || is_uprobe) && prog->type != BPF_PROG_TYPE_KPROBE) || 10220 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) || 10221 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) 10222 return -EINVAL; 10223 10224 if (prog->type == BPF_PROG_TYPE_KPROBE && prog->aux->sleepable && !is_uprobe) 10225 /* only uprobe programs are allowed to be sleepable */ 10226 return -EINVAL; 10227 10228 /* Kprobe override only works for kprobes, not uprobes. */ 10229 if (prog->kprobe_override && !is_kprobe) 10230 return -EINVAL; 10231 10232 if (is_tracepoint || is_syscall_tp) { 10233 int off = trace_event_get_offsets(event->tp_event); 10234 10235 if (prog->aux->max_ctx_offset > off) 10236 return -EACCES; 10237 } 10238 10239 return perf_event_attach_bpf_prog(event, prog, bpf_cookie); 10240 } 10241 10242 void perf_event_free_bpf_prog(struct perf_event *event) 10243 { 10244 if (!perf_event_is_tracing(event)) { 10245 perf_event_free_bpf_handler(event); 10246 return; 10247 } 10248 perf_event_detach_bpf_prog(event); 10249 } 10250 10251 #else 10252 10253 static inline void perf_tp_register(void) 10254 { 10255 } 10256 10257 static void perf_event_free_filter(struct perf_event *event) 10258 { 10259 } 10260 10261 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog, 10262 u64 bpf_cookie) 10263 { 10264 return -ENOENT; 10265 } 10266 10267 void perf_event_free_bpf_prog(struct perf_event *event) 10268 { 10269 } 10270 #endif /* CONFIG_EVENT_TRACING */ 10271 10272 #ifdef CONFIG_HAVE_HW_BREAKPOINT 10273 void perf_bp_event(struct perf_event *bp, void *data) 10274 { 10275 struct perf_sample_data sample; 10276 struct pt_regs *regs = data; 10277 10278 perf_sample_data_init(&sample, bp->attr.bp_addr, 0); 10279 10280 if (!bp->hw.state && !perf_exclude_event(bp, regs)) 10281 perf_swevent_event(bp, 1, &sample, regs); 10282 } 10283 #endif 10284 10285 /* 10286 * Allocate a new address filter 10287 */ 10288 static struct perf_addr_filter * 10289 perf_addr_filter_new(struct perf_event *event, struct list_head *filters) 10290 { 10291 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu); 10292 struct perf_addr_filter *filter; 10293 10294 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node); 10295 if (!filter) 10296 return NULL; 10297 10298 INIT_LIST_HEAD(&filter->entry); 10299 list_add_tail(&filter->entry, filters); 10300 10301 return filter; 10302 } 10303 10304 static void free_filters_list(struct list_head *filters) 10305 { 10306 struct perf_addr_filter *filter, *iter; 10307 10308 list_for_each_entry_safe(filter, iter, filters, entry) { 10309 path_put(&filter->path); 10310 list_del(&filter->entry); 10311 kfree(filter); 10312 } 10313 } 10314 10315 /* 10316 * Free existing address filters and optionally install new ones 10317 */ 10318 static void perf_addr_filters_splice(struct perf_event *event, 10319 struct list_head *head) 10320 { 10321 unsigned long flags; 10322 LIST_HEAD(list); 10323 10324 if (!has_addr_filter(event)) 10325 return; 10326 10327 /* don't bother with children, they don't have their own filters */ 10328 if (event->parent) 10329 return; 10330 10331 raw_spin_lock_irqsave(&event->addr_filters.lock, flags); 10332 10333 list_splice_init(&event->addr_filters.list, &list); 10334 if (head) 10335 list_splice(head, &event->addr_filters.list); 10336 10337 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags); 10338 10339 free_filters_list(&list); 10340 } 10341 10342 /* 10343 * Scan through mm's vmas and see if one of them matches the 10344 * @filter; if so, adjust filter's address range. 10345 * Called with mm::mmap_lock down for reading. 10346 */ 10347 static void perf_addr_filter_apply(struct perf_addr_filter *filter, 10348 struct mm_struct *mm, 10349 struct perf_addr_filter_range *fr) 10350 { 10351 struct vm_area_struct *vma; 10352 VMA_ITERATOR(vmi, mm, 0); 10353 10354 for_each_vma(vmi, vma) { 10355 if (!vma->vm_file) 10356 continue; 10357 10358 if (perf_addr_filter_vma_adjust(filter, vma, fr)) 10359 return; 10360 } 10361 } 10362 10363 /* 10364 * Update event's address range filters based on the 10365 * task's existing mappings, if any. 10366 */ 10367 static void perf_event_addr_filters_apply(struct perf_event *event) 10368 { 10369 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 10370 struct task_struct *task = READ_ONCE(event->ctx->task); 10371 struct perf_addr_filter *filter; 10372 struct mm_struct *mm = NULL; 10373 unsigned int count = 0; 10374 unsigned long flags; 10375 10376 /* 10377 * We may observe TASK_TOMBSTONE, which means that the event tear-down 10378 * will stop on the parent's child_mutex that our caller is also holding 10379 */ 10380 if (task == TASK_TOMBSTONE) 10381 return; 10382 10383 if (ifh->nr_file_filters) { 10384 mm = get_task_mm(task); 10385 if (!mm) 10386 goto restart; 10387 10388 mmap_read_lock(mm); 10389 } 10390 10391 raw_spin_lock_irqsave(&ifh->lock, flags); 10392 list_for_each_entry(filter, &ifh->list, entry) { 10393 if (filter->path.dentry) { 10394 /* 10395 * Adjust base offset if the filter is associated to a 10396 * binary that needs to be mapped: 10397 */ 10398 event->addr_filter_ranges[count].start = 0; 10399 event->addr_filter_ranges[count].size = 0; 10400 10401 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]); 10402 } else { 10403 event->addr_filter_ranges[count].start = filter->offset; 10404 event->addr_filter_ranges[count].size = filter->size; 10405 } 10406 10407 count++; 10408 } 10409 10410 event->addr_filters_gen++; 10411 raw_spin_unlock_irqrestore(&ifh->lock, flags); 10412 10413 if (ifh->nr_file_filters) { 10414 mmap_read_unlock(mm); 10415 10416 mmput(mm); 10417 } 10418 10419 restart: 10420 perf_event_stop(event, 1); 10421 } 10422 10423 /* 10424 * Address range filtering: limiting the data to certain 10425 * instruction address ranges. Filters are ioctl()ed to us from 10426 * userspace as ascii strings. 10427 * 10428 * Filter string format: 10429 * 10430 * ACTION RANGE_SPEC 10431 * where ACTION is one of the 10432 * * "filter": limit the trace to this region 10433 * * "start": start tracing from this address 10434 * * "stop": stop tracing at this address/region; 10435 * RANGE_SPEC is 10436 * * for kernel addresses: <start address>[/<size>] 10437 * * for object files: <start address>[/<size>]@</path/to/object/file> 10438 * 10439 * if <size> is not specified or is zero, the range is treated as a single 10440 * address; not valid for ACTION=="filter". 10441 */ 10442 enum { 10443 IF_ACT_NONE = -1, 10444 IF_ACT_FILTER, 10445 IF_ACT_START, 10446 IF_ACT_STOP, 10447 IF_SRC_FILE, 10448 IF_SRC_KERNEL, 10449 IF_SRC_FILEADDR, 10450 IF_SRC_KERNELADDR, 10451 }; 10452 10453 enum { 10454 IF_STATE_ACTION = 0, 10455 IF_STATE_SOURCE, 10456 IF_STATE_END, 10457 }; 10458 10459 static const match_table_t if_tokens = { 10460 { IF_ACT_FILTER, "filter" }, 10461 { IF_ACT_START, "start" }, 10462 { IF_ACT_STOP, "stop" }, 10463 { IF_SRC_FILE, "%u/%u@%s" }, 10464 { IF_SRC_KERNEL, "%u/%u" }, 10465 { IF_SRC_FILEADDR, "%u@%s" }, 10466 { IF_SRC_KERNELADDR, "%u" }, 10467 { IF_ACT_NONE, NULL }, 10468 }; 10469 10470 /* 10471 * Address filter string parser 10472 */ 10473 static int 10474 perf_event_parse_addr_filter(struct perf_event *event, char *fstr, 10475 struct list_head *filters) 10476 { 10477 struct perf_addr_filter *filter = NULL; 10478 char *start, *orig, *filename = NULL; 10479 substring_t args[MAX_OPT_ARGS]; 10480 int state = IF_STATE_ACTION, token; 10481 unsigned int kernel = 0; 10482 int ret = -EINVAL; 10483 10484 orig = fstr = kstrdup(fstr, GFP_KERNEL); 10485 if (!fstr) 10486 return -ENOMEM; 10487 10488 while ((start = strsep(&fstr, " ,\n")) != NULL) { 10489 static const enum perf_addr_filter_action_t actions[] = { 10490 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER, 10491 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START, 10492 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP, 10493 }; 10494 ret = -EINVAL; 10495 10496 if (!*start) 10497 continue; 10498 10499 /* filter definition begins */ 10500 if (state == IF_STATE_ACTION) { 10501 filter = perf_addr_filter_new(event, filters); 10502 if (!filter) 10503 goto fail; 10504 } 10505 10506 token = match_token(start, if_tokens, args); 10507 switch (token) { 10508 case IF_ACT_FILTER: 10509 case IF_ACT_START: 10510 case IF_ACT_STOP: 10511 if (state != IF_STATE_ACTION) 10512 goto fail; 10513 10514 filter->action = actions[token]; 10515 state = IF_STATE_SOURCE; 10516 break; 10517 10518 case IF_SRC_KERNELADDR: 10519 case IF_SRC_KERNEL: 10520 kernel = 1; 10521 fallthrough; 10522 10523 case IF_SRC_FILEADDR: 10524 case IF_SRC_FILE: 10525 if (state != IF_STATE_SOURCE) 10526 goto fail; 10527 10528 *args[0].to = 0; 10529 ret = kstrtoul(args[0].from, 0, &filter->offset); 10530 if (ret) 10531 goto fail; 10532 10533 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) { 10534 *args[1].to = 0; 10535 ret = kstrtoul(args[1].from, 0, &filter->size); 10536 if (ret) 10537 goto fail; 10538 } 10539 10540 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) { 10541 int fpos = token == IF_SRC_FILE ? 2 : 1; 10542 10543 kfree(filename); 10544 filename = match_strdup(&args[fpos]); 10545 if (!filename) { 10546 ret = -ENOMEM; 10547 goto fail; 10548 } 10549 } 10550 10551 state = IF_STATE_END; 10552 break; 10553 10554 default: 10555 goto fail; 10556 } 10557 10558 /* 10559 * Filter definition is fully parsed, validate and install it. 10560 * Make sure that it doesn't contradict itself or the event's 10561 * attribute. 10562 */ 10563 if (state == IF_STATE_END) { 10564 ret = -EINVAL; 10565 10566 /* 10567 * ACTION "filter" must have a non-zero length region 10568 * specified. 10569 */ 10570 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER && 10571 !filter->size) 10572 goto fail; 10573 10574 if (!kernel) { 10575 if (!filename) 10576 goto fail; 10577 10578 /* 10579 * For now, we only support file-based filters 10580 * in per-task events; doing so for CPU-wide 10581 * events requires additional context switching 10582 * trickery, since same object code will be 10583 * mapped at different virtual addresses in 10584 * different processes. 10585 */ 10586 ret = -EOPNOTSUPP; 10587 if (!event->ctx->task) 10588 goto fail; 10589 10590 /* look up the path and grab its inode */ 10591 ret = kern_path(filename, LOOKUP_FOLLOW, 10592 &filter->path); 10593 if (ret) 10594 goto fail; 10595 10596 ret = -EINVAL; 10597 if (!filter->path.dentry || 10598 !S_ISREG(d_inode(filter->path.dentry) 10599 ->i_mode)) 10600 goto fail; 10601 10602 event->addr_filters.nr_file_filters++; 10603 } 10604 10605 /* ready to consume more filters */ 10606 kfree(filename); 10607 filename = NULL; 10608 state = IF_STATE_ACTION; 10609 filter = NULL; 10610 kernel = 0; 10611 } 10612 } 10613 10614 if (state != IF_STATE_ACTION) 10615 goto fail; 10616 10617 kfree(filename); 10618 kfree(orig); 10619 10620 return 0; 10621 10622 fail: 10623 kfree(filename); 10624 free_filters_list(filters); 10625 kfree(orig); 10626 10627 return ret; 10628 } 10629 10630 static int 10631 perf_event_set_addr_filter(struct perf_event *event, char *filter_str) 10632 { 10633 LIST_HEAD(filters); 10634 int ret; 10635 10636 /* 10637 * Since this is called in perf_ioctl() path, we're already holding 10638 * ctx::mutex. 10639 */ 10640 lockdep_assert_held(&event->ctx->mutex); 10641 10642 if (WARN_ON_ONCE(event->parent)) 10643 return -EINVAL; 10644 10645 ret = perf_event_parse_addr_filter(event, filter_str, &filters); 10646 if (ret) 10647 goto fail_clear_files; 10648 10649 ret = event->pmu->addr_filters_validate(&filters); 10650 if (ret) 10651 goto fail_free_filters; 10652 10653 /* remove existing filters, if any */ 10654 perf_addr_filters_splice(event, &filters); 10655 10656 /* install new filters */ 10657 perf_event_for_each_child(event, perf_event_addr_filters_apply); 10658 10659 return ret; 10660 10661 fail_free_filters: 10662 free_filters_list(&filters); 10663 10664 fail_clear_files: 10665 event->addr_filters.nr_file_filters = 0; 10666 10667 return ret; 10668 } 10669 10670 static int perf_event_set_filter(struct perf_event *event, void __user *arg) 10671 { 10672 int ret = -EINVAL; 10673 char *filter_str; 10674 10675 filter_str = strndup_user(arg, PAGE_SIZE); 10676 if (IS_ERR(filter_str)) 10677 return PTR_ERR(filter_str); 10678 10679 #ifdef CONFIG_EVENT_TRACING 10680 if (perf_event_is_tracing(event)) { 10681 struct perf_event_context *ctx = event->ctx; 10682 10683 /* 10684 * Beware, here be dragons!! 10685 * 10686 * the tracepoint muck will deadlock against ctx->mutex, but 10687 * the tracepoint stuff does not actually need it. So 10688 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we 10689 * already have a reference on ctx. 10690 * 10691 * This can result in event getting moved to a different ctx, 10692 * but that does not affect the tracepoint state. 10693 */ 10694 mutex_unlock(&ctx->mutex); 10695 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str); 10696 mutex_lock(&ctx->mutex); 10697 } else 10698 #endif 10699 if (has_addr_filter(event)) 10700 ret = perf_event_set_addr_filter(event, filter_str); 10701 10702 kfree(filter_str); 10703 return ret; 10704 } 10705 10706 /* 10707 * hrtimer based swevent callback 10708 */ 10709 10710 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer) 10711 { 10712 enum hrtimer_restart ret = HRTIMER_RESTART; 10713 struct perf_sample_data data; 10714 struct pt_regs *regs; 10715 struct perf_event *event; 10716 u64 period; 10717 10718 event = container_of(hrtimer, struct perf_event, hw.hrtimer); 10719 10720 if (event->state != PERF_EVENT_STATE_ACTIVE) 10721 return HRTIMER_NORESTART; 10722 10723 event->pmu->read(event); 10724 10725 perf_sample_data_init(&data, 0, event->hw.last_period); 10726 regs = get_irq_regs(); 10727 10728 if (regs && !perf_exclude_event(event, regs)) { 10729 if (!(event->attr.exclude_idle && is_idle_task(current))) 10730 if (__perf_event_overflow(event, 1, &data, regs)) 10731 ret = HRTIMER_NORESTART; 10732 } 10733 10734 period = max_t(u64, 10000, event->hw.sample_period); 10735 hrtimer_forward_now(hrtimer, ns_to_ktime(period)); 10736 10737 return ret; 10738 } 10739 10740 static void perf_swevent_start_hrtimer(struct perf_event *event) 10741 { 10742 struct hw_perf_event *hwc = &event->hw; 10743 s64 period; 10744 10745 if (!is_sampling_event(event)) 10746 return; 10747 10748 period = local64_read(&hwc->period_left); 10749 if (period) { 10750 if (period < 0) 10751 period = 10000; 10752 10753 local64_set(&hwc->period_left, 0); 10754 } else { 10755 period = max_t(u64, 10000, hwc->sample_period); 10756 } 10757 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period), 10758 HRTIMER_MODE_REL_PINNED_HARD); 10759 } 10760 10761 static void perf_swevent_cancel_hrtimer(struct perf_event *event) 10762 { 10763 struct hw_perf_event *hwc = &event->hw; 10764 10765 if (is_sampling_event(event)) { 10766 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer); 10767 local64_set(&hwc->period_left, ktime_to_ns(remaining)); 10768 10769 hrtimer_cancel(&hwc->hrtimer); 10770 } 10771 } 10772 10773 static void perf_swevent_init_hrtimer(struct perf_event *event) 10774 { 10775 struct hw_perf_event *hwc = &event->hw; 10776 10777 if (!is_sampling_event(event)) 10778 return; 10779 10780 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); 10781 hwc->hrtimer.function = perf_swevent_hrtimer; 10782 10783 /* 10784 * Since hrtimers have a fixed rate, we can do a static freq->period 10785 * mapping and avoid the whole period adjust feedback stuff. 10786 */ 10787 if (event->attr.freq) { 10788 long freq = event->attr.sample_freq; 10789 10790 event->attr.sample_period = NSEC_PER_SEC / freq; 10791 hwc->sample_period = event->attr.sample_period; 10792 local64_set(&hwc->period_left, hwc->sample_period); 10793 hwc->last_period = hwc->sample_period; 10794 event->attr.freq = 0; 10795 } 10796 } 10797 10798 /* 10799 * Software event: cpu wall time clock 10800 */ 10801 10802 static void cpu_clock_event_update(struct perf_event *event) 10803 { 10804 s64 prev; 10805 u64 now; 10806 10807 now = local_clock(); 10808 prev = local64_xchg(&event->hw.prev_count, now); 10809 local64_add(now - prev, &event->count); 10810 } 10811 10812 static void cpu_clock_event_start(struct perf_event *event, int flags) 10813 { 10814 local64_set(&event->hw.prev_count, local_clock()); 10815 perf_swevent_start_hrtimer(event); 10816 } 10817 10818 static void cpu_clock_event_stop(struct perf_event *event, int flags) 10819 { 10820 perf_swevent_cancel_hrtimer(event); 10821 cpu_clock_event_update(event); 10822 } 10823 10824 static int cpu_clock_event_add(struct perf_event *event, int flags) 10825 { 10826 if (flags & PERF_EF_START) 10827 cpu_clock_event_start(event, flags); 10828 perf_event_update_userpage(event); 10829 10830 return 0; 10831 } 10832 10833 static void cpu_clock_event_del(struct perf_event *event, int flags) 10834 { 10835 cpu_clock_event_stop(event, flags); 10836 } 10837 10838 static void cpu_clock_event_read(struct perf_event *event) 10839 { 10840 cpu_clock_event_update(event); 10841 } 10842 10843 static int cpu_clock_event_init(struct perf_event *event) 10844 { 10845 if (event->attr.type != PERF_TYPE_SOFTWARE) 10846 return -ENOENT; 10847 10848 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK) 10849 return -ENOENT; 10850 10851 /* 10852 * no branch sampling for software events 10853 */ 10854 if (has_branch_stack(event)) 10855 return -EOPNOTSUPP; 10856 10857 perf_swevent_init_hrtimer(event); 10858 10859 return 0; 10860 } 10861 10862 static struct pmu perf_cpu_clock = { 10863 .task_ctx_nr = perf_sw_context, 10864 10865 .capabilities = PERF_PMU_CAP_NO_NMI, 10866 10867 .event_init = cpu_clock_event_init, 10868 .add = cpu_clock_event_add, 10869 .del = cpu_clock_event_del, 10870 .start = cpu_clock_event_start, 10871 .stop = cpu_clock_event_stop, 10872 .read = cpu_clock_event_read, 10873 }; 10874 10875 /* 10876 * Software event: task time clock 10877 */ 10878 10879 static void task_clock_event_update(struct perf_event *event, u64 now) 10880 { 10881 u64 prev; 10882 s64 delta; 10883 10884 prev = local64_xchg(&event->hw.prev_count, now); 10885 delta = now - prev; 10886 local64_add(delta, &event->count); 10887 } 10888 10889 static void task_clock_event_start(struct perf_event *event, int flags) 10890 { 10891 local64_set(&event->hw.prev_count, event->ctx->time); 10892 perf_swevent_start_hrtimer(event); 10893 } 10894 10895 static void task_clock_event_stop(struct perf_event *event, int flags) 10896 { 10897 perf_swevent_cancel_hrtimer(event); 10898 task_clock_event_update(event, event->ctx->time); 10899 } 10900 10901 static int task_clock_event_add(struct perf_event *event, int flags) 10902 { 10903 if (flags & PERF_EF_START) 10904 task_clock_event_start(event, flags); 10905 perf_event_update_userpage(event); 10906 10907 return 0; 10908 } 10909 10910 static void task_clock_event_del(struct perf_event *event, int flags) 10911 { 10912 task_clock_event_stop(event, PERF_EF_UPDATE); 10913 } 10914 10915 static void task_clock_event_read(struct perf_event *event) 10916 { 10917 u64 now = perf_clock(); 10918 u64 delta = now - event->ctx->timestamp; 10919 u64 time = event->ctx->time + delta; 10920 10921 task_clock_event_update(event, time); 10922 } 10923 10924 static int task_clock_event_init(struct perf_event *event) 10925 { 10926 if (event->attr.type != PERF_TYPE_SOFTWARE) 10927 return -ENOENT; 10928 10929 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK) 10930 return -ENOENT; 10931 10932 /* 10933 * no branch sampling for software events 10934 */ 10935 if (has_branch_stack(event)) 10936 return -EOPNOTSUPP; 10937 10938 perf_swevent_init_hrtimer(event); 10939 10940 return 0; 10941 } 10942 10943 static struct pmu perf_task_clock = { 10944 .task_ctx_nr = perf_sw_context, 10945 10946 .capabilities = PERF_PMU_CAP_NO_NMI, 10947 10948 .event_init = task_clock_event_init, 10949 .add = task_clock_event_add, 10950 .del = task_clock_event_del, 10951 .start = task_clock_event_start, 10952 .stop = task_clock_event_stop, 10953 .read = task_clock_event_read, 10954 }; 10955 10956 static void perf_pmu_nop_void(struct pmu *pmu) 10957 { 10958 } 10959 10960 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags) 10961 { 10962 } 10963 10964 static int perf_pmu_nop_int(struct pmu *pmu) 10965 { 10966 return 0; 10967 } 10968 10969 static int perf_event_nop_int(struct perf_event *event, u64 value) 10970 { 10971 return 0; 10972 } 10973 10974 static DEFINE_PER_CPU(unsigned int, nop_txn_flags); 10975 10976 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags) 10977 { 10978 __this_cpu_write(nop_txn_flags, flags); 10979 10980 if (flags & ~PERF_PMU_TXN_ADD) 10981 return; 10982 10983 perf_pmu_disable(pmu); 10984 } 10985 10986 static int perf_pmu_commit_txn(struct pmu *pmu) 10987 { 10988 unsigned int flags = __this_cpu_read(nop_txn_flags); 10989 10990 __this_cpu_write(nop_txn_flags, 0); 10991 10992 if (flags & ~PERF_PMU_TXN_ADD) 10993 return 0; 10994 10995 perf_pmu_enable(pmu); 10996 return 0; 10997 } 10998 10999 static void perf_pmu_cancel_txn(struct pmu *pmu) 11000 { 11001 unsigned int flags = __this_cpu_read(nop_txn_flags); 11002 11003 __this_cpu_write(nop_txn_flags, 0); 11004 11005 if (flags & ~PERF_PMU_TXN_ADD) 11006 return; 11007 11008 perf_pmu_enable(pmu); 11009 } 11010 11011 static int perf_event_idx_default(struct perf_event *event) 11012 { 11013 return 0; 11014 } 11015 11016 /* 11017 * Ensures all contexts with the same task_ctx_nr have the same 11018 * pmu_cpu_context too. 11019 */ 11020 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn) 11021 { 11022 struct pmu *pmu; 11023 11024 if (ctxn < 0) 11025 return NULL; 11026 11027 list_for_each_entry(pmu, &pmus, entry) { 11028 if (pmu->task_ctx_nr == ctxn) 11029 return pmu->pmu_cpu_context; 11030 } 11031 11032 return NULL; 11033 } 11034 11035 static void free_pmu_context(struct pmu *pmu) 11036 { 11037 /* 11038 * Static contexts such as perf_sw_context have a global lifetime 11039 * and may be shared between different PMUs. Avoid freeing them 11040 * when a single PMU is going away. 11041 */ 11042 if (pmu->task_ctx_nr > perf_invalid_context) 11043 return; 11044 11045 free_percpu(pmu->pmu_cpu_context); 11046 } 11047 11048 /* 11049 * Let userspace know that this PMU supports address range filtering: 11050 */ 11051 static ssize_t nr_addr_filters_show(struct device *dev, 11052 struct device_attribute *attr, 11053 char *page) 11054 { 11055 struct pmu *pmu = dev_get_drvdata(dev); 11056 11057 return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters); 11058 } 11059 DEVICE_ATTR_RO(nr_addr_filters); 11060 11061 static struct idr pmu_idr; 11062 11063 static ssize_t 11064 type_show(struct device *dev, struct device_attribute *attr, char *page) 11065 { 11066 struct pmu *pmu = dev_get_drvdata(dev); 11067 11068 return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->type); 11069 } 11070 static DEVICE_ATTR_RO(type); 11071 11072 static ssize_t 11073 perf_event_mux_interval_ms_show(struct device *dev, 11074 struct device_attribute *attr, 11075 char *page) 11076 { 11077 struct pmu *pmu = dev_get_drvdata(dev); 11078 11079 return scnprintf(page, PAGE_SIZE - 1, "%d\n", pmu->hrtimer_interval_ms); 11080 } 11081 11082 static DEFINE_MUTEX(mux_interval_mutex); 11083 11084 static ssize_t 11085 perf_event_mux_interval_ms_store(struct device *dev, 11086 struct device_attribute *attr, 11087 const char *buf, size_t count) 11088 { 11089 struct pmu *pmu = dev_get_drvdata(dev); 11090 int timer, cpu, ret; 11091 11092 ret = kstrtoint(buf, 0, &timer); 11093 if (ret) 11094 return ret; 11095 11096 if (timer < 1) 11097 return -EINVAL; 11098 11099 /* same value, noting to do */ 11100 if (timer == pmu->hrtimer_interval_ms) 11101 return count; 11102 11103 mutex_lock(&mux_interval_mutex); 11104 pmu->hrtimer_interval_ms = timer; 11105 11106 /* update all cpuctx for this PMU */ 11107 cpus_read_lock(); 11108 for_each_online_cpu(cpu) { 11109 struct perf_cpu_context *cpuctx; 11110 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 11111 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer); 11112 11113 cpu_function_call(cpu, 11114 (remote_function_f)perf_mux_hrtimer_restart, cpuctx); 11115 } 11116 cpus_read_unlock(); 11117 mutex_unlock(&mux_interval_mutex); 11118 11119 return count; 11120 } 11121 static DEVICE_ATTR_RW(perf_event_mux_interval_ms); 11122 11123 static struct attribute *pmu_dev_attrs[] = { 11124 &dev_attr_type.attr, 11125 &dev_attr_perf_event_mux_interval_ms.attr, 11126 NULL, 11127 }; 11128 ATTRIBUTE_GROUPS(pmu_dev); 11129 11130 static int pmu_bus_running; 11131 static struct bus_type pmu_bus = { 11132 .name = "event_source", 11133 .dev_groups = pmu_dev_groups, 11134 }; 11135 11136 static void pmu_dev_release(struct device *dev) 11137 { 11138 kfree(dev); 11139 } 11140 11141 static int pmu_dev_alloc(struct pmu *pmu) 11142 { 11143 int ret = -ENOMEM; 11144 11145 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL); 11146 if (!pmu->dev) 11147 goto out; 11148 11149 pmu->dev->groups = pmu->attr_groups; 11150 device_initialize(pmu->dev); 11151 ret = dev_set_name(pmu->dev, "%s", pmu->name); 11152 if (ret) 11153 goto free_dev; 11154 11155 dev_set_drvdata(pmu->dev, pmu); 11156 pmu->dev->bus = &pmu_bus; 11157 pmu->dev->release = pmu_dev_release; 11158 ret = device_add(pmu->dev); 11159 if (ret) 11160 goto free_dev; 11161 11162 /* For PMUs with address filters, throw in an extra attribute: */ 11163 if (pmu->nr_addr_filters) 11164 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters); 11165 11166 if (ret) 11167 goto del_dev; 11168 11169 if (pmu->attr_update) 11170 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update); 11171 11172 if (ret) 11173 goto del_dev; 11174 11175 out: 11176 return ret; 11177 11178 del_dev: 11179 device_del(pmu->dev); 11180 11181 free_dev: 11182 put_device(pmu->dev); 11183 goto out; 11184 } 11185 11186 static struct lock_class_key cpuctx_mutex; 11187 static struct lock_class_key cpuctx_lock; 11188 11189 int perf_pmu_register(struct pmu *pmu, const char *name, int type) 11190 { 11191 int cpu, ret, max = PERF_TYPE_MAX; 11192 11193 mutex_lock(&pmus_lock); 11194 ret = -ENOMEM; 11195 pmu->pmu_disable_count = alloc_percpu(int); 11196 if (!pmu->pmu_disable_count) 11197 goto unlock; 11198 11199 pmu->type = -1; 11200 if (!name) 11201 goto skip_type; 11202 pmu->name = name; 11203 11204 if (type != PERF_TYPE_SOFTWARE) { 11205 if (type >= 0) 11206 max = type; 11207 11208 ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL); 11209 if (ret < 0) 11210 goto free_pdc; 11211 11212 WARN_ON(type >= 0 && ret != type); 11213 11214 type = ret; 11215 } 11216 pmu->type = type; 11217 11218 if (pmu_bus_running) { 11219 ret = pmu_dev_alloc(pmu); 11220 if (ret) 11221 goto free_idr; 11222 } 11223 11224 skip_type: 11225 if (pmu->task_ctx_nr == perf_hw_context) { 11226 static int hw_context_taken = 0; 11227 11228 /* 11229 * Other than systems with heterogeneous CPUs, it never makes 11230 * sense for two PMUs to share perf_hw_context. PMUs which are 11231 * uncore must use perf_invalid_context. 11232 */ 11233 if (WARN_ON_ONCE(hw_context_taken && 11234 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS))) 11235 pmu->task_ctx_nr = perf_invalid_context; 11236 11237 hw_context_taken = 1; 11238 } 11239 11240 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr); 11241 if (pmu->pmu_cpu_context) 11242 goto got_cpu_context; 11243 11244 ret = -ENOMEM; 11245 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context); 11246 if (!pmu->pmu_cpu_context) 11247 goto free_dev; 11248 11249 for_each_possible_cpu(cpu) { 11250 struct perf_cpu_context *cpuctx; 11251 11252 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 11253 __perf_event_init_context(&cpuctx->ctx); 11254 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex); 11255 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock); 11256 cpuctx->ctx.pmu = pmu; 11257 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask); 11258 11259 __perf_mux_hrtimer_init(cpuctx, cpu); 11260 11261 cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default); 11262 cpuctx->heap = cpuctx->heap_default; 11263 } 11264 11265 got_cpu_context: 11266 if (!pmu->start_txn) { 11267 if (pmu->pmu_enable) { 11268 /* 11269 * If we have pmu_enable/pmu_disable calls, install 11270 * transaction stubs that use that to try and batch 11271 * hardware accesses. 11272 */ 11273 pmu->start_txn = perf_pmu_start_txn; 11274 pmu->commit_txn = perf_pmu_commit_txn; 11275 pmu->cancel_txn = perf_pmu_cancel_txn; 11276 } else { 11277 pmu->start_txn = perf_pmu_nop_txn; 11278 pmu->commit_txn = perf_pmu_nop_int; 11279 pmu->cancel_txn = perf_pmu_nop_void; 11280 } 11281 } 11282 11283 if (!pmu->pmu_enable) { 11284 pmu->pmu_enable = perf_pmu_nop_void; 11285 pmu->pmu_disable = perf_pmu_nop_void; 11286 } 11287 11288 if (!pmu->check_period) 11289 pmu->check_period = perf_event_nop_int; 11290 11291 if (!pmu->event_idx) 11292 pmu->event_idx = perf_event_idx_default; 11293 11294 /* 11295 * Ensure the TYPE_SOFTWARE PMUs are at the head of the list, 11296 * since these cannot be in the IDR. This way the linear search 11297 * is fast, provided a valid software event is provided. 11298 */ 11299 if (type == PERF_TYPE_SOFTWARE || !name) 11300 list_add_rcu(&pmu->entry, &pmus); 11301 else 11302 list_add_tail_rcu(&pmu->entry, &pmus); 11303 11304 atomic_set(&pmu->exclusive_cnt, 0); 11305 ret = 0; 11306 unlock: 11307 mutex_unlock(&pmus_lock); 11308 11309 return ret; 11310 11311 free_dev: 11312 device_del(pmu->dev); 11313 put_device(pmu->dev); 11314 11315 free_idr: 11316 if (pmu->type != PERF_TYPE_SOFTWARE) 11317 idr_remove(&pmu_idr, pmu->type); 11318 11319 free_pdc: 11320 free_percpu(pmu->pmu_disable_count); 11321 goto unlock; 11322 } 11323 EXPORT_SYMBOL_GPL(perf_pmu_register); 11324 11325 void perf_pmu_unregister(struct pmu *pmu) 11326 { 11327 mutex_lock(&pmus_lock); 11328 list_del_rcu(&pmu->entry); 11329 11330 /* 11331 * We dereference the pmu list under both SRCU and regular RCU, so 11332 * synchronize against both of those. 11333 */ 11334 synchronize_srcu(&pmus_srcu); 11335 synchronize_rcu(); 11336 11337 free_percpu(pmu->pmu_disable_count); 11338 if (pmu->type != PERF_TYPE_SOFTWARE) 11339 idr_remove(&pmu_idr, pmu->type); 11340 if (pmu_bus_running) { 11341 if (pmu->nr_addr_filters) 11342 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters); 11343 device_del(pmu->dev); 11344 put_device(pmu->dev); 11345 } 11346 free_pmu_context(pmu); 11347 mutex_unlock(&pmus_lock); 11348 } 11349 EXPORT_SYMBOL_GPL(perf_pmu_unregister); 11350 11351 static inline bool has_extended_regs(struct perf_event *event) 11352 { 11353 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) || 11354 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK); 11355 } 11356 11357 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event) 11358 { 11359 struct perf_event_context *ctx = NULL; 11360 int ret; 11361 11362 if (!try_module_get(pmu->module)) 11363 return -ENODEV; 11364 11365 /* 11366 * A number of pmu->event_init() methods iterate the sibling_list to, 11367 * for example, validate if the group fits on the PMU. Therefore, 11368 * if this is a sibling event, acquire the ctx->mutex to protect 11369 * the sibling_list. 11370 */ 11371 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) { 11372 /* 11373 * This ctx->mutex can nest when we're called through 11374 * inheritance. See the perf_event_ctx_lock_nested() comment. 11375 */ 11376 ctx = perf_event_ctx_lock_nested(event->group_leader, 11377 SINGLE_DEPTH_NESTING); 11378 BUG_ON(!ctx); 11379 } 11380 11381 event->pmu = pmu; 11382 ret = pmu->event_init(event); 11383 11384 if (ctx) 11385 perf_event_ctx_unlock(event->group_leader, ctx); 11386 11387 if (!ret) { 11388 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) && 11389 has_extended_regs(event)) 11390 ret = -EOPNOTSUPP; 11391 11392 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE && 11393 event_has_any_exclude_flag(event)) 11394 ret = -EINVAL; 11395 11396 if (ret && event->destroy) 11397 event->destroy(event); 11398 } 11399 11400 if (ret) 11401 module_put(pmu->module); 11402 11403 return ret; 11404 } 11405 11406 static struct pmu *perf_init_event(struct perf_event *event) 11407 { 11408 bool extended_type = false; 11409 int idx, type, ret; 11410 struct pmu *pmu; 11411 11412 idx = srcu_read_lock(&pmus_srcu); 11413 11414 /* Try parent's PMU first: */ 11415 if (event->parent && event->parent->pmu) { 11416 pmu = event->parent->pmu; 11417 ret = perf_try_init_event(pmu, event); 11418 if (!ret) 11419 goto unlock; 11420 } 11421 11422 /* 11423 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE 11424 * are often aliases for PERF_TYPE_RAW. 11425 */ 11426 type = event->attr.type; 11427 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE) { 11428 type = event->attr.config >> PERF_PMU_TYPE_SHIFT; 11429 if (!type) { 11430 type = PERF_TYPE_RAW; 11431 } else { 11432 extended_type = true; 11433 event->attr.config &= PERF_HW_EVENT_MASK; 11434 } 11435 } 11436 11437 again: 11438 rcu_read_lock(); 11439 pmu = idr_find(&pmu_idr, type); 11440 rcu_read_unlock(); 11441 if (pmu) { 11442 if (event->attr.type != type && type != PERF_TYPE_RAW && 11443 !(pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE)) 11444 goto fail; 11445 11446 ret = perf_try_init_event(pmu, event); 11447 if (ret == -ENOENT && event->attr.type != type && !extended_type) { 11448 type = event->attr.type; 11449 goto again; 11450 } 11451 11452 if (ret) 11453 pmu = ERR_PTR(ret); 11454 11455 goto unlock; 11456 } 11457 11458 list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) { 11459 ret = perf_try_init_event(pmu, event); 11460 if (!ret) 11461 goto unlock; 11462 11463 if (ret != -ENOENT) { 11464 pmu = ERR_PTR(ret); 11465 goto unlock; 11466 } 11467 } 11468 fail: 11469 pmu = ERR_PTR(-ENOENT); 11470 unlock: 11471 srcu_read_unlock(&pmus_srcu, idx); 11472 11473 return pmu; 11474 } 11475 11476 static void attach_sb_event(struct perf_event *event) 11477 { 11478 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu); 11479 11480 raw_spin_lock(&pel->lock); 11481 list_add_rcu(&event->sb_list, &pel->list); 11482 raw_spin_unlock(&pel->lock); 11483 } 11484 11485 /* 11486 * We keep a list of all !task (and therefore per-cpu) events 11487 * that need to receive side-band records. 11488 * 11489 * This avoids having to scan all the various PMU per-cpu contexts 11490 * looking for them. 11491 */ 11492 static void account_pmu_sb_event(struct perf_event *event) 11493 { 11494 if (is_sb_event(event)) 11495 attach_sb_event(event); 11496 } 11497 11498 static void account_event_cpu(struct perf_event *event, int cpu) 11499 { 11500 if (event->parent) 11501 return; 11502 11503 if (is_cgroup_event(event)) 11504 atomic_inc(&per_cpu(perf_cgroup_events, cpu)); 11505 } 11506 11507 /* Freq events need the tick to stay alive (see perf_event_task_tick). */ 11508 static void account_freq_event_nohz(void) 11509 { 11510 #ifdef CONFIG_NO_HZ_FULL 11511 /* Lock so we don't race with concurrent unaccount */ 11512 spin_lock(&nr_freq_lock); 11513 if (atomic_inc_return(&nr_freq_events) == 1) 11514 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS); 11515 spin_unlock(&nr_freq_lock); 11516 #endif 11517 } 11518 11519 static void account_freq_event(void) 11520 { 11521 if (tick_nohz_full_enabled()) 11522 account_freq_event_nohz(); 11523 else 11524 atomic_inc(&nr_freq_events); 11525 } 11526 11527 11528 static void account_event(struct perf_event *event) 11529 { 11530 bool inc = false; 11531 11532 if (event->parent) 11533 return; 11534 11535 if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB)) 11536 inc = true; 11537 if (event->attr.mmap || event->attr.mmap_data) 11538 atomic_inc(&nr_mmap_events); 11539 if (event->attr.build_id) 11540 atomic_inc(&nr_build_id_events); 11541 if (event->attr.comm) 11542 atomic_inc(&nr_comm_events); 11543 if (event->attr.namespaces) 11544 atomic_inc(&nr_namespaces_events); 11545 if (event->attr.cgroup) 11546 atomic_inc(&nr_cgroup_events); 11547 if (event->attr.task) 11548 atomic_inc(&nr_task_events); 11549 if (event->attr.freq) 11550 account_freq_event(); 11551 if (event->attr.context_switch) { 11552 atomic_inc(&nr_switch_events); 11553 inc = true; 11554 } 11555 if (has_branch_stack(event)) 11556 inc = true; 11557 if (is_cgroup_event(event)) 11558 inc = true; 11559 if (event->attr.ksymbol) 11560 atomic_inc(&nr_ksymbol_events); 11561 if (event->attr.bpf_event) 11562 atomic_inc(&nr_bpf_events); 11563 if (event->attr.text_poke) 11564 atomic_inc(&nr_text_poke_events); 11565 11566 if (inc) { 11567 /* 11568 * We need the mutex here because static_branch_enable() 11569 * must complete *before* the perf_sched_count increment 11570 * becomes visible. 11571 */ 11572 if (atomic_inc_not_zero(&perf_sched_count)) 11573 goto enabled; 11574 11575 mutex_lock(&perf_sched_mutex); 11576 if (!atomic_read(&perf_sched_count)) { 11577 static_branch_enable(&perf_sched_events); 11578 /* 11579 * Guarantee that all CPUs observe they key change and 11580 * call the perf scheduling hooks before proceeding to 11581 * install events that need them. 11582 */ 11583 synchronize_rcu(); 11584 } 11585 /* 11586 * Now that we have waited for the sync_sched(), allow further 11587 * increments to by-pass the mutex. 11588 */ 11589 atomic_inc(&perf_sched_count); 11590 mutex_unlock(&perf_sched_mutex); 11591 } 11592 enabled: 11593 11594 account_event_cpu(event, event->cpu); 11595 11596 account_pmu_sb_event(event); 11597 } 11598 11599 /* 11600 * Allocate and initialize an event structure 11601 */ 11602 static struct perf_event * 11603 perf_event_alloc(struct perf_event_attr *attr, int cpu, 11604 struct task_struct *task, 11605 struct perf_event *group_leader, 11606 struct perf_event *parent_event, 11607 perf_overflow_handler_t overflow_handler, 11608 void *context, int cgroup_fd) 11609 { 11610 struct pmu *pmu; 11611 struct perf_event *event; 11612 struct hw_perf_event *hwc; 11613 long err = -EINVAL; 11614 int node; 11615 11616 if ((unsigned)cpu >= nr_cpu_ids) { 11617 if (!task || cpu != -1) 11618 return ERR_PTR(-EINVAL); 11619 } 11620 if (attr->sigtrap && !task) { 11621 /* Requires a task: avoid signalling random tasks. */ 11622 return ERR_PTR(-EINVAL); 11623 } 11624 11625 node = (cpu >= 0) ? cpu_to_node(cpu) : -1; 11626 event = kmem_cache_alloc_node(perf_event_cache, GFP_KERNEL | __GFP_ZERO, 11627 node); 11628 if (!event) 11629 return ERR_PTR(-ENOMEM); 11630 11631 /* 11632 * Single events are their own group leaders, with an 11633 * empty sibling list: 11634 */ 11635 if (!group_leader) 11636 group_leader = event; 11637 11638 mutex_init(&event->child_mutex); 11639 INIT_LIST_HEAD(&event->child_list); 11640 11641 INIT_LIST_HEAD(&event->event_entry); 11642 INIT_LIST_HEAD(&event->sibling_list); 11643 INIT_LIST_HEAD(&event->active_list); 11644 init_event_group(event); 11645 INIT_LIST_HEAD(&event->rb_entry); 11646 INIT_LIST_HEAD(&event->active_entry); 11647 INIT_LIST_HEAD(&event->addr_filters.list); 11648 INIT_HLIST_NODE(&event->hlist_entry); 11649 11650 11651 init_waitqueue_head(&event->waitq); 11652 init_irq_work(&event->pending_irq, perf_pending_irq); 11653 init_task_work(&event->pending_task, perf_pending_task); 11654 11655 mutex_init(&event->mmap_mutex); 11656 raw_spin_lock_init(&event->addr_filters.lock); 11657 11658 atomic_long_set(&event->refcount, 1); 11659 event->cpu = cpu; 11660 event->attr = *attr; 11661 event->group_leader = group_leader; 11662 event->pmu = NULL; 11663 event->oncpu = -1; 11664 11665 event->parent = parent_event; 11666 11667 event->ns = get_pid_ns(task_active_pid_ns(current)); 11668 event->id = atomic64_inc_return(&perf_event_id); 11669 11670 event->state = PERF_EVENT_STATE_INACTIVE; 11671 11672 if (parent_event) 11673 event->event_caps = parent_event->event_caps; 11674 11675 if (task) { 11676 event->attach_state = PERF_ATTACH_TASK; 11677 /* 11678 * XXX pmu::event_init needs to know what task to account to 11679 * and we cannot use the ctx information because we need the 11680 * pmu before we get a ctx. 11681 */ 11682 event->hw.target = get_task_struct(task); 11683 } 11684 11685 event->clock = &local_clock; 11686 if (parent_event) 11687 event->clock = parent_event->clock; 11688 11689 if (!overflow_handler && parent_event) { 11690 overflow_handler = parent_event->overflow_handler; 11691 context = parent_event->overflow_handler_context; 11692 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING) 11693 if (overflow_handler == bpf_overflow_handler) { 11694 struct bpf_prog *prog = parent_event->prog; 11695 11696 bpf_prog_inc(prog); 11697 event->prog = prog; 11698 event->orig_overflow_handler = 11699 parent_event->orig_overflow_handler; 11700 } 11701 #endif 11702 } 11703 11704 if (overflow_handler) { 11705 event->overflow_handler = overflow_handler; 11706 event->overflow_handler_context = context; 11707 } else if (is_write_backward(event)){ 11708 event->overflow_handler = perf_event_output_backward; 11709 event->overflow_handler_context = NULL; 11710 } else { 11711 event->overflow_handler = perf_event_output_forward; 11712 event->overflow_handler_context = NULL; 11713 } 11714 11715 perf_event__state_init(event); 11716 11717 pmu = NULL; 11718 11719 hwc = &event->hw; 11720 hwc->sample_period = attr->sample_period; 11721 if (attr->freq && attr->sample_freq) 11722 hwc->sample_period = 1; 11723 hwc->last_period = hwc->sample_period; 11724 11725 local64_set(&hwc->period_left, hwc->sample_period); 11726 11727 /* 11728 * We currently do not support PERF_SAMPLE_READ on inherited events. 11729 * See perf_output_read(). 11730 */ 11731 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ)) 11732 goto err_ns; 11733 11734 if (!has_branch_stack(event)) 11735 event->attr.branch_sample_type = 0; 11736 11737 pmu = perf_init_event(event); 11738 if (IS_ERR(pmu)) { 11739 err = PTR_ERR(pmu); 11740 goto err_ns; 11741 } 11742 11743 /* 11744 * Disallow uncore-cgroup events, they don't make sense as the cgroup will 11745 * be different on other CPUs in the uncore mask. 11746 */ 11747 if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) { 11748 err = -EINVAL; 11749 goto err_pmu; 11750 } 11751 11752 if (event->attr.aux_output && 11753 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) { 11754 err = -EOPNOTSUPP; 11755 goto err_pmu; 11756 } 11757 11758 if (cgroup_fd != -1) { 11759 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader); 11760 if (err) 11761 goto err_pmu; 11762 } 11763 11764 err = exclusive_event_init(event); 11765 if (err) 11766 goto err_pmu; 11767 11768 if (has_addr_filter(event)) { 11769 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters, 11770 sizeof(struct perf_addr_filter_range), 11771 GFP_KERNEL); 11772 if (!event->addr_filter_ranges) { 11773 err = -ENOMEM; 11774 goto err_per_task; 11775 } 11776 11777 /* 11778 * Clone the parent's vma offsets: they are valid until exec() 11779 * even if the mm is not shared with the parent. 11780 */ 11781 if (event->parent) { 11782 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event); 11783 11784 raw_spin_lock_irq(&ifh->lock); 11785 memcpy(event->addr_filter_ranges, 11786 event->parent->addr_filter_ranges, 11787 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range)); 11788 raw_spin_unlock_irq(&ifh->lock); 11789 } 11790 11791 /* force hw sync on the address filters */ 11792 event->addr_filters_gen = 1; 11793 } 11794 11795 if (!event->parent) { 11796 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) { 11797 err = get_callchain_buffers(attr->sample_max_stack); 11798 if (err) 11799 goto err_addr_filters; 11800 } 11801 } 11802 11803 err = security_perf_event_alloc(event); 11804 if (err) 11805 goto err_callchain_buffer; 11806 11807 /* symmetric to unaccount_event() in _free_event() */ 11808 account_event(event); 11809 11810 return event; 11811 11812 err_callchain_buffer: 11813 if (!event->parent) { 11814 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) 11815 put_callchain_buffers(); 11816 } 11817 err_addr_filters: 11818 kfree(event->addr_filter_ranges); 11819 11820 err_per_task: 11821 exclusive_event_destroy(event); 11822 11823 err_pmu: 11824 if (is_cgroup_event(event)) 11825 perf_detach_cgroup(event); 11826 if (event->destroy) 11827 event->destroy(event); 11828 module_put(pmu->module); 11829 err_ns: 11830 if (event->hw.target) 11831 put_task_struct(event->hw.target); 11832 call_rcu(&event->rcu_head, free_event_rcu); 11833 11834 return ERR_PTR(err); 11835 } 11836 11837 static int perf_copy_attr(struct perf_event_attr __user *uattr, 11838 struct perf_event_attr *attr) 11839 { 11840 u32 size; 11841 int ret; 11842 11843 /* Zero the full structure, so that a short copy will be nice. */ 11844 memset(attr, 0, sizeof(*attr)); 11845 11846 ret = get_user(size, &uattr->size); 11847 if (ret) 11848 return ret; 11849 11850 /* ABI compatibility quirk: */ 11851 if (!size) 11852 size = PERF_ATTR_SIZE_VER0; 11853 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE) 11854 goto err_size; 11855 11856 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size); 11857 if (ret) { 11858 if (ret == -E2BIG) 11859 goto err_size; 11860 return ret; 11861 } 11862 11863 attr->size = size; 11864 11865 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3) 11866 return -EINVAL; 11867 11868 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1)) 11869 return -EINVAL; 11870 11871 if (attr->read_format & ~(PERF_FORMAT_MAX-1)) 11872 return -EINVAL; 11873 11874 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) { 11875 u64 mask = attr->branch_sample_type; 11876 11877 /* only using defined bits */ 11878 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1)) 11879 return -EINVAL; 11880 11881 /* at least one branch bit must be set */ 11882 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL)) 11883 return -EINVAL; 11884 11885 /* propagate priv level, when not set for branch */ 11886 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) { 11887 11888 /* exclude_kernel checked on syscall entry */ 11889 if (!attr->exclude_kernel) 11890 mask |= PERF_SAMPLE_BRANCH_KERNEL; 11891 11892 if (!attr->exclude_user) 11893 mask |= PERF_SAMPLE_BRANCH_USER; 11894 11895 if (!attr->exclude_hv) 11896 mask |= PERF_SAMPLE_BRANCH_HV; 11897 /* 11898 * adjust user setting (for HW filter setup) 11899 */ 11900 attr->branch_sample_type = mask; 11901 } 11902 /* privileged levels capture (kernel, hv): check permissions */ 11903 if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) { 11904 ret = perf_allow_kernel(attr); 11905 if (ret) 11906 return ret; 11907 } 11908 } 11909 11910 if (attr->sample_type & PERF_SAMPLE_REGS_USER) { 11911 ret = perf_reg_validate(attr->sample_regs_user); 11912 if (ret) 11913 return ret; 11914 } 11915 11916 if (attr->sample_type & PERF_SAMPLE_STACK_USER) { 11917 if (!arch_perf_have_user_stack_dump()) 11918 return -ENOSYS; 11919 11920 /* 11921 * We have __u32 type for the size, but so far 11922 * we can only use __u16 as maximum due to the 11923 * __u16 sample size limit. 11924 */ 11925 if (attr->sample_stack_user >= USHRT_MAX) 11926 return -EINVAL; 11927 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64))) 11928 return -EINVAL; 11929 } 11930 11931 if (!attr->sample_max_stack) 11932 attr->sample_max_stack = sysctl_perf_event_max_stack; 11933 11934 if (attr->sample_type & PERF_SAMPLE_REGS_INTR) 11935 ret = perf_reg_validate(attr->sample_regs_intr); 11936 11937 #ifndef CONFIG_CGROUP_PERF 11938 if (attr->sample_type & PERF_SAMPLE_CGROUP) 11939 return -EINVAL; 11940 #endif 11941 if ((attr->sample_type & PERF_SAMPLE_WEIGHT) && 11942 (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT)) 11943 return -EINVAL; 11944 11945 if (!attr->inherit && attr->inherit_thread) 11946 return -EINVAL; 11947 11948 if (attr->remove_on_exec && attr->enable_on_exec) 11949 return -EINVAL; 11950 11951 if (attr->sigtrap && !attr->remove_on_exec) 11952 return -EINVAL; 11953 11954 out: 11955 return ret; 11956 11957 err_size: 11958 put_user(sizeof(*attr), &uattr->size); 11959 ret = -E2BIG; 11960 goto out; 11961 } 11962 11963 static void mutex_lock_double(struct mutex *a, struct mutex *b) 11964 { 11965 if (b < a) 11966 swap(a, b); 11967 11968 mutex_lock(a); 11969 mutex_lock_nested(b, SINGLE_DEPTH_NESTING); 11970 } 11971 11972 static int 11973 perf_event_set_output(struct perf_event *event, struct perf_event *output_event) 11974 { 11975 struct perf_buffer *rb = NULL; 11976 int ret = -EINVAL; 11977 11978 if (!output_event) { 11979 mutex_lock(&event->mmap_mutex); 11980 goto set; 11981 } 11982 11983 /* don't allow circular references */ 11984 if (event == output_event) 11985 goto out; 11986 11987 /* 11988 * Don't allow cross-cpu buffers 11989 */ 11990 if (output_event->cpu != event->cpu) 11991 goto out; 11992 11993 /* 11994 * If its not a per-cpu rb, it must be the same task. 11995 */ 11996 if (output_event->cpu == -1 && output_event->ctx != event->ctx) 11997 goto out; 11998 11999 /* 12000 * Mixing clocks in the same buffer is trouble you don't need. 12001 */ 12002 if (output_event->clock != event->clock) 12003 goto out; 12004 12005 /* 12006 * Either writing ring buffer from beginning or from end. 12007 * Mixing is not allowed. 12008 */ 12009 if (is_write_backward(output_event) != is_write_backward(event)) 12010 goto out; 12011 12012 /* 12013 * If both events generate aux data, they must be on the same PMU 12014 */ 12015 if (has_aux(event) && has_aux(output_event) && 12016 event->pmu != output_event->pmu) 12017 goto out; 12018 12019 /* 12020 * Hold both mmap_mutex to serialize against perf_mmap_close(). Since 12021 * output_event is already on rb->event_list, and the list iteration 12022 * restarts after every removal, it is guaranteed this new event is 12023 * observed *OR* if output_event is already removed, it's guaranteed we 12024 * observe !rb->mmap_count. 12025 */ 12026 mutex_lock_double(&event->mmap_mutex, &output_event->mmap_mutex); 12027 set: 12028 /* Can't redirect output if we've got an active mmap() */ 12029 if (atomic_read(&event->mmap_count)) 12030 goto unlock; 12031 12032 if (output_event) { 12033 /* get the rb we want to redirect to */ 12034 rb = ring_buffer_get(output_event); 12035 if (!rb) 12036 goto unlock; 12037 12038 /* did we race against perf_mmap_close() */ 12039 if (!atomic_read(&rb->mmap_count)) { 12040 ring_buffer_put(rb); 12041 goto unlock; 12042 } 12043 } 12044 12045 ring_buffer_attach(event, rb); 12046 12047 ret = 0; 12048 unlock: 12049 mutex_unlock(&event->mmap_mutex); 12050 if (output_event) 12051 mutex_unlock(&output_event->mmap_mutex); 12052 12053 out: 12054 return ret; 12055 } 12056 12057 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id) 12058 { 12059 bool nmi_safe = false; 12060 12061 switch (clk_id) { 12062 case CLOCK_MONOTONIC: 12063 event->clock = &ktime_get_mono_fast_ns; 12064 nmi_safe = true; 12065 break; 12066 12067 case CLOCK_MONOTONIC_RAW: 12068 event->clock = &ktime_get_raw_fast_ns; 12069 nmi_safe = true; 12070 break; 12071 12072 case CLOCK_REALTIME: 12073 event->clock = &ktime_get_real_ns; 12074 break; 12075 12076 case CLOCK_BOOTTIME: 12077 event->clock = &ktime_get_boottime_ns; 12078 break; 12079 12080 case CLOCK_TAI: 12081 event->clock = &ktime_get_clocktai_ns; 12082 break; 12083 12084 default: 12085 return -EINVAL; 12086 } 12087 12088 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI)) 12089 return -EINVAL; 12090 12091 return 0; 12092 } 12093 12094 /* 12095 * Variation on perf_event_ctx_lock_nested(), except we take two context 12096 * mutexes. 12097 */ 12098 static struct perf_event_context * 12099 __perf_event_ctx_lock_double(struct perf_event *group_leader, 12100 struct perf_event_context *ctx) 12101 { 12102 struct perf_event_context *gctx; 12103 12104 again: 12105 rcu_read_lock(); 12106 gctx = READ_ONCE(group_leader->ctx); 12107 if (!refcount_inc_not_zero(&gctx->refcount)) { 12108 rcu_read_unlock(); 12109 goto again; 12110 } 12111 rcu_read_unlock(); 12112 12113 mutex_lock_double(&gctx->mutex, &ctx->mutex); 12114 12115 if (group_leader->ctx != gctx) { 12116 mutex_unlock(&ctx->mutex); 12117 mutex_unlock(&gctx->mutex); 12118 put_ctx(gctx); 12119 goto again; 12120 } 12121 12122 return gctx; 12123 } 12124 12125 static bool 12126 perf_check_permission(struct perf_event_attr *attr, struct task_struct *task) 12127 { 12128 unsigned int ptrace_mode = PTRACE_MODE_READ_REALCREDS; 12129 bool is_capable = perfmon_capable(); 12130 12131 if (attr->sigtrap) { 12132 /* 12133 * perf_event_attr::sigtrap sends signals to the other task. 12134 * Require the current task to also have CAP_KILL. 12135 */ 12136 rcu_read_lock(); 12137 is_capable &= ns_capable(__task_cred(task)->user_ns, CAP_KILL); 12138 rcu_read_unlock(); 12139 12140 /* 12141 * If the required capabilities aren't available, checks for 12142 * ptrace permissions: upgrade to ATTACH, since sending signals 12143 * can effectively change the target task. 12144 */ 12145 ptrace_mode = PTRACE_MODE_ATTACH_REALCREDS; 12146 } 12147 12148 /* 12149 * Preserve ptrace permission check for backwards compatibility. The 12150 * ptrace check also includes checks that the current task and other 12151 * task have matching uids, and is therefore not done here explicitly. 12152 */ 12153 return is_capable || ptrace_may_access(task, ptrace_mode); 12154 } 12155 12156 /** 12157 * sys_perf_event_open - open a performance event, associate it to a task/cpu 12158 * 12159 * @attr_uptr: event_id type attributes for monitoring/sampling 12160 * @pid: target pid 12161 * @cpu: target cpu 12162 * @group_fd: group leader event fd 12163 * @flags: perf event open flags 12164 */ 12165 SYSCALL_DEFINE5(perf_event_open, 12166 struct perf_event_attr __user *, attr_uptr, 12167 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags) 12168 { 12169 struct perf_event *group_leader = NULL, *output_event = NULL; 12170 struct perf_event *event, *sibling; 12171 struct perf_event_attr attr; 12172 struct perf_event_context *ctx, *gctx; 12173 struct file *event_file = NULL; 12174 struct fd group = {NULL, 0}; 12175 struct task_struct *task = NULL; 12176 struct pmu *pmu; 12177 int event_fd; 12178 int move_group = 0; 12179 int err; 12180 int f_flags = O_RDWR; 12181 int cgroup_fd = -1; 12182 12183 /* for future expandability... */ 12184 if (flags & ~PERF_FLAG_ALL) 12185 return -EINVAL; 12186 12187 /* Do we allow access to perf_event_open(2) ? */ 12188 err = security_perf_event_open(&attr, PERF_SECURITY_OPEN); 12189 if (err) 12190 return err; 12191 12192 err = perf_copy_attr(attr_uptr, &attr); 12193 if (err) 12194 return err; 12195 12196 if (!attr.exclude_kernel) { 12197 err = perf_allow_kernel(&attr); 12198 if (err) 12199 return err; 12200 } 12201 12202 if (attr.namespaces) { 12203 if (!perfmon_capable()) 12204 return -EACCES; 12205 } 12206 12207 if (attr.freq) { 12208 if (attr.sample_freq > sysctl_perf_event_sample_rate) 12209 return -EINVAL; 12210 } else { 12211 if (attr.sample_period & (1ULL << 63)) 12212 return -EINVAL; 12213 } 12214 12215 /* Only privileged users can get physical addresses */ 12216 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) { 12217 err = perf_allow_kernel(&attr); 12218 if (err) 12219 return err; 12220 } 12221 12222 /* REGS_INTR can leak data, lockdown must prevent this */ 12223 if (attr.sample_type & PERF_SAMPLE_REGS_INTR) { 12224 err = security_locked_down(LOCKDOWN_PERF); 12225 if (err) 12226 return err; 12227 } 12228 12229 /* 12230 * In cgroup mode, the pid argument is used to pass the fd 12231 * opened to the cgroup directory in cgroupfs. The cpu argument 12232 * designates the cpu on which to monitor threads from that 12233 * cgroup. 12234 */ 12235 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1)) 12236 return -EINVAL; 12237 12238 if (flags & PERF_FLAG_FD_CLOEXEC) 12239 f_flags |= O_CLOEXEC; 12240 12241 event_fd = get_unused_fd_flags(f_flags); 12242 if (event_fd < 0) 12243 return event_fd; 12244 12245 if (group_fd != -1) { 12246 err = perf_fget_light(group_fd, &group); 12247 if (err) 12248 goto err_fd; 12249 group_leader = group.file->private_data; 12250 if (flags & PERF_FLAG_FD_OUTPUT) 12251 output_event = group_leader; 12252 if (flags & PERF_FLAG_FD_NO_GROUP) 12253 group_leader = NULL; 12254 } 12255 12256 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) { 12257 task = find_lively_task_by_vpid(pid); 12258 if (IS_ERR(task)) { 12259 err = PTR_ERR(task); 12260 goto err_group_fd; 12261 } 12262 } 12263 12264 if (task && group_leader && 12265 group_leader->attr.inherit != attr.inherit) { 12266 err = -EINVAL; 12267 goto err_task; 12268 } 12269 12270 if (flags & PERF_FLAG_PID_CGROUP) 12271 cgroup_fd = pid; 12272 12273 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL, 12274 NULL, NULL, cgroup_fd); 12275 if (IS_ERR(event)) { 12276 err = PTR_ERR(event); 12277 goto err_task; 12278 } 12279 12280 if (is_sampling_event(event)) { 12281 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) { 12282 err = -EOPNOTSUPP; 12283 goto err_alloc; 12284 } 12285 } 12286 12287 /* 12288 * Special case software events and allow them to be part of 12289 * any hardware group. 12290 */ 12291 pmu = event->pmu; 12292 12293 if (attr.use_clockid) { 12294 err = perf_event_set_clock(event, attr.clockid); 12295 if (err) 12296 goto err_alloc; 12297 } 12298 12299 if (pmu->task_ctx_nr == perf_sw_context) 12300 event->event_caps |= PERF_EV_CAP_SOFTWARE; 12301 12302 if (group_leader) { 12303 if (is_software_event(event) && 12304 !in_software_context(group_leader)) { 12305 /* 12306 * If the event is a sw event, but the group_leader 12307 * is on hw context. 12308 * 12309 * Allow the addition of software events to hw 12310 * groups, this is safe because software events 12311 * never fail to schedule. 12312 */ 12313 pmu = group_leader->ctx->pmu; 12314 } else if (!is_software_event(event) && 12315 is_software_event(group_leader) && 12316 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) { 12317 /* 12318 * In case the group is a pure software group, and we 12319 * try to add a hardware event, move the whole group to 12320 * the hardware context. 12321 */ 12322 move_group = 1; 12323 } 12324 } 12325 12326 /* 12327 * Get the target context (task or percpu): 12328 */ 12329 ctx = find_get_context(pmu, task, event); 12330 if (IS_ERR(ctx)) { 12331 err = PTR_ERR(ctx); 12332 goto err_alloc; 12333 } 12334 12335 /* 12336 * Look up the group leader (we will attach this event to it): 12337 */ 12338 if (group_leader) { 12339 err = -EINVAL; 12340 12341 /* 12342 * Do not allow a recursive hierarchy (this new sibling 12343 * becoming part of another group-sibling): 12344 */ 12345 if (group_leader->group_leader != group_leader) 12346 goto err_context; 12347 12348 /* All events in a group should have the same clock */ 12349 if (group_leader->clock != event->clock) 12350 goto err_context; 12351 12352 /* 12353 * Make sure we're both events for the same CPU; 12354 * grouping events for different CPUs is broken; since 12355 * you can never concurrently schedule them anyhow. 12356 */ 12357 if (group_leader->cpu != event->cpu) 12358 goto err_context; 12359 12360 /* 12361 * Make sure we're both on the same task, or both 12362 * per-CPU events. 12363 */ 12364 if (group_leader->ctx->task != ctx->task) 12365 goto err_context; 12366 12367 /* 12368 * Do not allow to attach to a group in a different task 12369 * or CPU context. If we're moving SW events, we'll fix 12370 * this up later, so allow that. 12371 * 12372 * Racy, not holding group_leader->ctx->mutex, see comment with 12373 * perf_event_ctx_lock(). 12374 */ 12375 if (!move_group && group_leader->ctx != ctx) 12376 goto err_context; 12377 12378 /* 12379 * Only a group leader can be exclusive or pinned 12380 */ 12381 if (attr.exclusive || attr.pinned) 12382 goto err_context; 12383 } 12384 12385 if (output_event) { 12386 err = perf_event_set_output(event, output_event); 12387 if (err) 12388 goto err_context; 12389 } 12390 12391 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, 12392 f_flags); 12393 if (IS_ERR(event_file)) { 12394 err = PTR_ERR(event_file); 12395 event_file = NULL; 12396 goto err_context; 12397 } 12398 12399 if (task) { 12400 err = down_read_interruptible(&task->signal->exec_update_lock); 12401 if (err) 12402 goto err_file; 12403 12404 /* 12405 * We must hold exec_update_lock across this and any potential 12406 * perf_install_in_context() call for this new event to 12407 * serialize against exec() altering our credentials (and the 12408 * perf_event_exit_task() that could imply). 12409 */ 12410 err = -EACCES; 12411 if (!perf_check_permission(&attr, task)) 12412 goto err_cred; 12413 } 12414 12415 if (move_group) { 12416 gctx = __perf_event_ctx_lock_double(group_leader, ctx); 12417 12418 if (gctx->task == TASK_TOMBSTONE) { 12419 err = -ESRCH; 12420 goto err_locked; 12421 } 12422 12423 /* 12424 * Check if we raced against another sys_perf_event_open() call 12425 * moving the software group underneath us. 12426 */ 12427 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) { 12428 /* 12429 * If someone moved the group out from under us, check 12430 * if this new event wound up on the same ctx, if so 12431 * its the regular !move_group case, otherwise fail. 12432 */ 12433 if (gctx != ctx) { 12434 err = -EINVAL; 12435 goto err_locked; 12436 } else { 12437 perf_event_ctx_unlock(group_leader, gctx); 12438 move_group = 0; 12439 goto not_move_group; 12440 } 12441 } 12442 12443 /* 12444 * Failure to create exclusive events returns -EBUSY. 12445 */ 12446 err = -EBUSY; 12447 if (!exclusive_event_installable(group_leader, ctx)) 12448 goto err_locked; 12449 12450 for_each_sibling_event(sibling, group_leader) { 12451 if (!exclusive_event_installable(sibling, ctx)) 12452 goto err_locked; 12453 } 12454 } else { 12455 mutex_lock(&ctx->mutex); 12456 12457 /* 12458 * Now that we hold ctx->lock, (re)validate group_leader->ctx == ctx, 12459 * see the group_leader && !move_group test earlier. 12460 */ 12461 if (group_leader && group_leader->ctx != ctx) { 12462 err = -EINVAL; 12463 goto err_locked; 12464 } 12465 } 12466 not_move_group: 12467 12468 if (ctx->task == TASK_TOMBSTONE) { 12469 err = -ESRCH; 12470 goto err_locked; 12471 } 12472 12473 if (!perf_event_validate_size(event)) { 12474 err = -E2BIG; 12475 goto err_locked; 12476 } 12477 12478 if (!task) { 12479 /* 12480 * Check if the @cpu we're creating an event for is online. 12481 * 12482 * We use the perf_cpu_context::ctx::mutex to serialize against 12483 * the hotplug notifiers. See perf_event_{init,exit}_cpu(). 12484 */ 12485 struct perf_cpu_context *cpuctx = 12486 container_of(ctx, struct perf_cpu_context, ctx); 12487 12488 if (!cpuctx->online) { 12489 err = -ENODEV; 12490 goto err_locked; 12491 } 12492 } 12493 12494 if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) { 12495 err = -EINVAL; 12496 goto err_locked; 12497 } 12498 12499 /* 12500 * Must be under the same ctx::mutex as perf_install_in_context(), 12501 * because we need to serialize with concurrent event creation. 12502 */ 12503 if (!exclusive_event_installable(event, ctx)) { 12504 err = -EBUSY; 12505 goto err_locked; 12506 } 12507 12508 WARN_ON_ONCE(ctx->parent_ctx); 12509 12510 /* 12511 * This is the point on no return; we cannot fail hereafter. This is 12512 * where we start modifying current state. 12513 */ 12514 12515 if (move_group) { 12516 /* 12517 * See perf_event_ctx_lock() for comments on the details 12518 * of swizzling perf_event::ctx. 12519 */ 12520 perf_remove_from_context(group_leader, 0); 12521 put_ctx(gctx); 12522 12523 for_each_sibling_event(sibling, group_leader) { 12524 perf_remove_from_context(sibling, 0); 12525 put_ctx(gctx); 12526 } 12527 12528 /* 12529 * Wait for everybody to stop referencing the events through 12530 * the old lists, before installing it on new lists. 12531 */ 12532 synchronize_rcu(); 12533 12534 /* 12535 * Install the group siblings before the group leader. 12536 * 12537 * Because a group leader will try and install the entire group 12538 * (through the sibling list, which is still in-tact), we can 12539 * end up with siblings installed in the wrong context. 12540 * 12541 * By installing siblings first we NO-OP because they're not 12542 * reachable through the group lists. 12543 */ 12544 for_each_sibling_event(sibling, group_leader) { 12545 perf_event__state_init(sibling); 12546 perf_install_in_context(ctx, sibling, sibling->cpu); 12547 get_ctx(ctx); 12548 } 12549 12550 /* 12551 * Removing from the context ends up with disabled 12552 * event. What we want here is event in the initial 12553 * startup state, ready to be add into new context. 12554 */ 12555 perf_event__state_init(group_leader); 12556 perf_install_in_context(ctx, group_leader, group_leader->cpu); 12557 get_ctx(ctx); 12558 } 12559 12560 /* 12561 * Precalculate sample_data sizes; do while holding ctx::mutex such 12562 * that we're serialized against further additions and before 12563 * perf_install_in_context() which is the point the event is active and 12564 * can use these values. 12565 */ 12566 perf_event__header_size(event); 12567 perf_event__id_header_size(event); 12568 12569 event->owner = current; 12570 12571 perf_install_in_context(ctx, event, event->cpu); 12572 perf_unpin_context(ctx); 12573 12574 if (move_group) 12575 perf_event_ctx_unlock(group_leader, gctx); 12576 mutex_unlock(&ctx->mutex); 12577 12578 if (task) { 12579 up_read(&task->signal->exec_update_lock); 12580 put_task_struct(task); 12581 } 12582 12583 mutex_lock(¤t->perf_event_mutex); 12584 list_add_tail(&event->owner_entry, ¤t->perf_event_list); 12585 mutex_unlock(¤t->perf_event_mutex); 12586 12587 /* 12588 * Drop the reference on the group_event after placing the 12589 * new event on the sibling_list. This ensures destruction 12590 * of the group leader will find the pointer to itself in 12591 * perf_group_detach(). 12592 */ 12593 fdput(group); 12594 fd_install(event_fd, event_file); 12595 return event_fd; 12596 12597 err_locked: 12598 if (move_group) 12599 perf_event_ctx_unlock(group_leader, gctx); 12600 mutex_unlock(&ctx->mutex); 12601 err_cred: 12602 if (task) 12603 up_read(&task->signal->exec_update_lock); 12604 err_file: 12605 fput(event_file); 12606 err_context: 12607 perf_unpin_context(ctx); 12608 put_ctx(ctx); 12609 err_alloc: 12610 /* 12611 * If event_file is set, the fput() above will have called ->release() 12612 * and that will take care of freeing the event. 12613 */ 12614 if (!event_file) 12615 free_event(event); 12616 err_task: 12617 if (task) 12618 put_task_struct(task); 12619 err_group_fd: 12620 fdput(group); 12621 err_fd: 12622 put_unused_fd(event_fd); 12623 return err; 12624 } 12625 12626 /** 12627 * perf_event_create_kernel_counter 12628 * 12629 * @attr: attributes of the counter to create 12630 * @cpu: cpu in which the counter is bound 12631 * @task: task to profile (NULL for percpu) 12632 * @overflow_handler: callback to trigger when we hit the event 12633 * @context: context data could be used in overflow_handler callback 12634 */ 12635 struct perf_event * 12636 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu, 12637 struct task_struct *task, 12638 perf_overflow_handler_t overflow_handler, 12639 void *context) 12640 { 12641 struct perf_event_context *ctx; 12642 struct perf_event *event; 12643 int err; 12644 12645 /* 12646 * Grouping is not supported for kernel events, neither is 'AUX', 12647 * make sure the caller's intentions are adjusted. 12648 */ 12649 if (attr->aux_output) 12650 return ERR_PTR(-EINVAL); 12651 12652 event = perf_event_alloc(attr, cpu, task, NULL, NULL, 12653 overflow_handler, context, -1); 12654 if (IS_ERR(event)) { 12655 err = PTR_ERR(event); 12656 goto err; 12657 } 12658 12659 /* Mark owner so we could distinguish it from user events. */ 12660 event->owner = TASK_TOMBSTONE; 12661 12662 /* 12663 * Get the target context (task or percpu): 12664 */ 12665 ctx = find_get_context(event->pmu, task, event); 12666 if (IS_ERR(ctx)) { 12667 err = PTR_ERR(ctx); 12668 goto err_free; 12669 } 12670 12671 WARN_ON_ONCE(ctx->parent_ctx); 12672 mutex_lock(&ctx->mutex); 12673 if (ctx->task == TASK_TOMBSTONE) { 12674 err = -ESRCH; 12675 goto err_unlock; 12676 } 12677 12678 if (!task) { 12679 /* 12680 * Check if the @cpu we're creating an event for is online. 12681 * 12682 * We use the perf_cpu_context::ctx::mutex to serialize against 12683 * the hotplug notifiers. See perf_event_{init,exit}_cpu(). 12684 */ 12685 struct perf_cpu_context *cpuctx = 12686 container_of(ctx, struct perf_cpu_context, ctx); 12687 if (!cpuctx->online) { 12688 err = -ENODEV; 12689 goto err_unlock; 12690 } 12691 } 12692 12693 if (!exclusive_event_installable(event, ctx)) { 12694 err = -EBUSY; 12695 goto err_unlock; 12696 } 12697 12698 perf_install_in_context(ctx, event, event->cpu); 12699 perf_unpin_context(ctx); 12700 mutex_unlock(&ctx->mutex); 12701 12702 return event; 12703 12704 err_unlock: 12705 mutex_unlock(&ctx->mutex); 12706 perf_unpin_context(ctx); 12707 put_ctx(ctx); 12708 err_free: 12709 free_event(event); 12710 err: 12711 return ERR_PTR(err); 12712 } 12713 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter); 12714 12715 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu) 12716 { 12717 struct perf_event_context *src_ctx; 12718 struct perf_event_context *dst_ctx; 12719 struct perf_event *event, *tmp; 12720 LIST_HEAD(events); 12721 12722 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx; 12723 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx; 12724 12725 /* 12726 * See perf_event_ctx_lock() for comments on the details 12727 * of swizzling perf_event::ctx. 12728 */ 12729 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex); 12730 list_for_each_entry_safe(event, tmp, &src_ctx->event_list, 12731 event_entry) { 12732 perf_remove_from_context(event, 0); 12733 unaccount_event_cpu(event, src_cpu); 12734 put_ctx(src_ctx); 12735 list_add(&event->migrate_entry, &events); 12736 } 12737 12738 /* 12739 * Wait for the events to quiesce before re-instating them. 12740 */ 12741 synchronize_rcu(); 12742 12743 /* 12744 * Re-instate events in 2 passes. 12745 * 12746 * Skip over group leaders and only install siblings on this first 12747 * pass, siblings will not get enabled without a leader, however a 12748 * leader will enable its siblings, even if those are still on the old 12749 * context. 12750 */ 12751 list_for_each_entry_safe(event, tmp, &events, migrate_entry) { 12752 if (event->group_leader == event) 12753 continue; 12754 12755 list_del(&event->migrate_entry); 12756 if (event->state >= PERF_EVENT_STATE_OFF) 12757 event->state = PERF_EVENT_STATE_INACTIVE; 12758 account_event_cpu(event, dst_cpu); 12759 perf_install_in_context(dst_ctx, event, dst_cpu); 12760 get_ctx(dst_ctx); 12761 } 12762 12763 /* 12764 * Once all the siblings are setup properly, install the group leaders 12765 * to make it go. 12766 */ 12767 list_for_each_entry_safe(event, tmp, &events, migrate_entry) { 12768 list_del(&event->migrate_entry); 12769 if (event->state >= PERF_EVENT_STATE_OFF) 12770 event->state = PERF_EVENT_STATE_INACTIVE; 12771 account_event_cpu(event, dst_cpu); 12772 perf_install_in_context(dst_ctx, event, dst_cpu); 12773 get_ctx(dst_ctx); 12774 } 12775 mutex_unlock(&dst_ctx->mutex); 12776 mutex_unlock(&src_ctx->mutex); 12777 } 12778 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context); 12779 12780 static void sync_child_event(struct perf_event *child_event) 12781 { 12782 struct perf_event *parent_event = child_event->parent; 12783 u64 child_val; 12784 12785 if (child_event->attr.inherit_stat) { 12786 struct task_struct *task = child_event->ctx->task; 12787 12788 if (task && task != TASK_TOMBSTONE) 12789 perf_event_read_event(child_event, task); 12790 } 12791 12792 child_val = perf_event_count(child_event); 12793 12794 /* 12795 * Add back the child's count to the parent's count: 12796 */ 12797 atomic64_add(child_val, &parent_event->child_count); 12798 atomic64_add(child_event->total_time_enabled, 12799 &parent_event->child_total_time_enabled); 12800 atomic64_add(child_event->total_time_running, 12801 &parent_event->child_total_time_running); 12802 } 12803 12804 static void 12805 perf_event_exit_event(struct perf_event *event, struct perf_event_context *ctx) 12806 { 12807 struct perf_event *parent_event = event->parent; 12808 unsigned long detach_flags = 0; 12809 12810 if (parent_event) { 12811 /* 12812 * Do not destroy the 'original' grouping; because of the 12813 * context switch optimization the original events could've 12814 * ended up in a random child task. 12815 * 12816 * If we were to destroy the original group, all group related 12817 * operations would cease to function properly after this 12818 * random child dies. 12819 * 12820 * Do destroy all inherited groups, we don't care about those 12821 * and being thorough is better. 12822 */ 12823 detach_flags = DETACH_GROUP | DETACH_CHILD; 12824 mutex_lock(&parent_event->child_mutex); 12825 } 12826 12827 perf_remove_from_context(event, detach_flags); 12828 12829 raw_spin_lock_irq(&ctx->lock); 12830 if (event->state > PERF_EVENT_STATE_EXIT) 12831 perf_event_set_state(event, PERF_EVENT_STATE_EXIT); 12832 raw_spin_unlock_irq(&ctx->lock); 12833 12834 /* 12835 * Child events can be freed. 12836 */ 12837 if (parent_event) { 12838 mutex_unlock(&parent_event->child_mutex); 12839 /* 12840 * Kick perf_poll() for is_event_hup(); 12841 */ 12842 perf_event_wakeup(parent_event); 12843 free_event(event); 12844 put_event(parent_event); 12845 return; 12846 } 12847 12848 /* 12849 * Parent events are governed by their filedesc, retain them. 12850 */ 12851 perf_event_wakeup(event); 12852 } 12853 12854 static void perf_event_exit_task_context(struct task_struct *child, int ctxn) 12855 { 12856 struct perf_event_context *child_ctx, *clone_ctx = NULL; 12857 struct perf_event *child_event, *next; 12858 12859 WARN_ON_ONCE(child != current); 12860 12861 child_ctx = perf_pin_task_context(child, ctxn); 12862 if (!child_ctx) 12863 return; 12864 12865 /* 12866 * In order to reduce the amount of tricky in ctx tear-down, we hold 12867 * ctx::mutex over the entire thing. This serializes against almost 12868 * everything that wants to access the ctx. 12869 * 12870 * The exception is sys_perf_event_open() / 12871 * perf_event_create_kernel_count() which does find_get_context() 12872 * without ctx::mutex (it cannot because of the move_group double mutex 12873 * lock thing). See the comments in perf_install_in_context(). 12874 */ 12875 mutex_lock(&child_ctx->mutex); 12876 12877 /* 12878 * In a single ctx::lock section, de-schedule the events and detach the 12879 * context from the task such that we cannot ever get it scheduled back 12880 * in. 12881 */ 12882 raw_spin_lock_irq(&child_ctx->lock); 12883 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL); 12884 12885 /* 12886 * Now that the context is inactive, destroy the task <-> ctx relation 12887 * and mark the context dead. 12888 */ 12889 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL); 12890 put_ctx(child_ctx); /* cannot be last */ 12891 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE); 12892 put_task_struct(current); /* cannot be last */ 12893 12894 clone_ctx = unclone_ctx(child_ctx); 12895 raw_spin_unlock_irq(&child_ctx->lock); 12896 12897 if (clone_ctx) 12898 put_ctx(clone_ctx); 12899 12900 /* 12901 * Report the task dead after unscheduling the events so that we 12902 * won't get any samples after PERF_RECORD_EXIT. We can however still 12903 * get a few PERF_RECORD_READ events. 12904 */ 12905 perf_event_task(child, child_ctx, 0); 12906 12907 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry) 12908 perf_event_exit_event(child_event, child_ctx); 12909 12910 mutex_unlock(&child_ctx->mutex); 12911 12912 put_ctx(child_ctx); 12913 } 12914 12915 /* 12916 * When a child task exits, feed back event values to parent events. 12917 * 12918 * Can be called with exec_update_lock held when called from 12919 * setup_new_exec(). 12920 */ 12921 void perf_event_exit_task(struct task_struct *child) 12922 { 12923 struct perf_event *event, *tmp; 12924 int ctxn; 12925 12926 mutex_lock(&child->perf_event_mutex); 12927 list_for_each_entry_safe(event, tmp, &child->perf_event_list, 12928 owner_entry) { 12929 list_del_init(&event->owner_entry); 12930 12931 /* 12932 * Ensure the list deletion is visible before we clear 12933 * the owner, closes a race against perf_release() where 12934 * we need to serialize on the owner->perf_event_mutex. 12935 */ 12936 smp_store_release(&event->owner, NULL); 12937 } 12938 mutex_unlock(&child->perf_event_mutex); 12939 12940 for_each_task_context_nr(ctxn) 12941 perf_event_exit_task_context(child, ctxn); 12942 12943 /* 12944 * The perf_event_exit_task_context calls perf_event_task 12945 * with child's task_ctx, which generates EXIT events for 12946 * child contexts and sets child->perf_event_ctxp[] to NULL. 12947 * At this point we need to send EXIT events to cpu contexts. 12948 */ 12949 perf_event_task(child, NULL, 0); 12950 } 12951 12952 static void perf_free_event(struct perf_event *event, 12953 struct perf_event_context *ctx) 12954 { 12955 struct perf_event *parent = event->parent; 12956 12957 if (WARN_ON_ONCE(!parent)) 12958 return; 12959 12960 mutex_lock(&parent->child_mutex); 12961 list_del_init(&event->child_list); 12962 mutex_unlock(&parent->child_mutex); 12963 12964 put_event(parent); 12965 12966 raw_spin_lock_irq(&ctx->lock); 12967 perf_group_detach(event); 12968 list_del_event(event, ctx); 12969 raw_spin_unlock_irq(&ctx->lock); 12970 free_event(event); 12971 } 12972 12973 /* 12974 * Free a context as created by inheritance by perf_event_init_task() below, 12975 * used by fork() in case of fail. 12976 * 12977 * Even though the task has never lived, the context and events have been 12978 * exposed through the child_list, so we must take care tearing it all down. 12979 */ 12980 void perf_event_free_task(struct task_struct *task) 12981 { 12982 struct perf_event_context *ctx; 12983 struct perf_event *event, *tmp; 12984 int ctxn; 12985 12986 for_each_task_context_nr(ctxn) { 12987 ctx = task->perf_event_ctxp[ctxn]; 12988 if (!ctx) 12989 continue; 12990 12991 mutex_lock(&ctx->mutex); 12992 raw_spin_lock_irq(&ctx->lock); 12993 /* 12994 * Destroy the task <-> ctx relation and mark the context dead. 12995 * 12996 * This is important because even though the task hasn't been 12997 * exposed yet the context has been (through child_list). 12998 */ 12999 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL); 13000 WRITE_ONCE(ctx->task, TASK_TOMBSTONE); 13001 put_task_struct(task); /* cannot be last */ 13002 raw_spin_unlock_irq(&ctx->lock); 13003 13004 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry) 13005 perf_free_event(event, ctx); 13006 13007 mutex_unlock(&ctx->mutex); 13008 13009 /* 13010 * perf_event_release_kernel() could've stolen some of our 13011 * child events and still have them on its free_list. In that 13012 * case we must wait for these events to have been freed (in 13013 * particular all their references to this task must've been 13014 * dropped). 13015 * 13016 * Without this copy_process() will unconditionally free this 13017 * task (irrespective of its reference count) and 13018 * _free_event()'s put_task_struct(event->hw.target) will be a 13019 * use-after-free. 13020 * 13021 * Wait for all events to drop their context reference. 13022 */ 13023 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1); 13024 put_ctx(ctx); /* must be last */ 13025 } 13026 } 13027 13028 void perf_event_delayed_put(struct task_struct *task) 13029 { 13030 int ctxn; 13031 13032 for_each_task_context_nr(ctxn) 13033 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]); 13034 } 13035 13036 struct file *perf_event_get(unsigned int fd) 13037 { 13038 struct file *file = fget(fd); 13039 if (!file) 13040 return ERR_PTR(-EBADF); 13041 13042 if (file->f_op != &perf_fops) { 13043 fput(file); 13044 return ERR_PTR(-EBADF); 13045 } 13046 13047 return file; 13048 } 13049 13050 const struct perf_event *perf_get_event(struct file *file) 13051 { 13052 if (file->f_op != &perf_fops) 13053 return ERR_PTR(-EINVAL); 13054 13055 return file->private_data; 13056 } 13057 13058 const struct perf_event_attr *perf_event_attrs(struct perf_event *event) 13059 { 13060 if (!event) 13061 return ERR_PTR(-EINVAL); 13062 13063 return &event->attr; 13064 } 13065 13066 /* 13067 * Inherit an event from parent task to child task. 13068 * 13069 * Returns: 13070 * - valid pointer on success 13071 * - NULL for orphaned events 13072 * - IS_ERR() on error 13073 */ 13074 static struct perf_event * 13075 inherit_event(struct perf_event *parent_event, 13076 struct task_struct *parent, 13077 struct perf_event_context *parent_ctx, 13078 struct task_struct *child, 13079 struct perf_event *group_leader, 13080 struct perf_event_context *child_ctx) 13081 { 13082 enum perf_event_state parent_state = parent_event->state; 13083 struct perf_event *child_event; 13084 unsigned long flags; 13085 13086 /* 13087 * Instead of creating recursive hierarchies of events, 13088 * we link inherited events back to the original parent, 13089 * which has a filp for sure, which we use as the reference 13090 * count: 13091 */ 13092 if (parent_event->parent) 13093 parent_event = parent_event->parent; 13094 13095 child_event = perf_event_alloc(&parent_event->attr, 13096 parent_event->cpu, 13097 child, 13098 group_leader, parent_event, 13099 NULL, NULL, -1); 13100 if (IS_ERR(child_event)) 13101 return child_event; 13102 13103 13104 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) && 13105 !child_ctx->task_ctx_data) { 13106 struct pmu *pmu = child_event->pmu; 13107 13108 child_ctx->task_ctx_data = alloc_task_ctx_data(pmu); 13109 if (!child_ctx->task_ctx_data) { 13110 free_event(child_event); 13111 return ERR_PTR(-ENOMEM); 13112 } 13113 } 13114 13115 /* 13116 * is_orphaned_event() and list_add_tail(&parent_event->child_list) 13117 * must be under the same lock in order to serialize against 13118 * perf_event_release_kernel(), such that either we must observe 13119 * is_orphaned_event() or they will observe us on the child_list. 13120 */ 13121 mutex_lock(&parent_event->child_mutex); 13122 if (is_orphaned_event(parent_event) || 13123 !atomic_long_inc_not_zero(&parent_event->refcount)) { 13124 mutex_unlock(&parent_event->child_mutex); 13125 /* task_ctx_data is freed with child_ctx */ 13126 free_event(child_event); 13127 return NULL; 13128 } 13129 13130 get_ctx(child_ctx); 13131 13132 /* 13133 * Make the child state follow the state of the parent event, 13134 * not its attr.disabled bit. We hold the parent's mutex, 13135 * so we won't race with perf_event_{en, dis}able_family. 13136 */ 13137 if (parent_state >= PERF_EVENT_STATE_INACTIVE) 13138 child_event->state = PERF_EVENT_STATE_INACTIVE; 13139 else 13140 child_event->state = PERF_EVENT_STATE_OFF; 13141 13142 if (parent_event->attr.freq) { 13143 u64 sample_period = parent_event->hw.sample_period; 13144 struct hw_perf_event *hwc = &child_event->hw; 13145 13146 hwc->sample_period = sample_period; 13147 hwc->last_period = sample_period; 13148 13149 local64_set(&hwc->period_left, sample_period); 13150 } 13151 13152 child_event->ctx = child_ctx; 13153 child_event->overflow_handler = parent_event->overflow_handler; 13154 child_event->overflow_handler_context 13155 = parent_event->overflow_handler_context; 13156 13157 /* 13158 * Precalculate sample_data sizes 13159 */ 13160 perf_event__header_size(child_event); 13161 perf_event__id_header_size(child_event); 13162 13163 /* 13164 * Link it up in the child's context: 13165 */ 13166 raw_spin_lock_irqsave(&child_ctx->lock, flags); 13167 add_event_to_ctx(child_event, child_ctx); 13168 child_event->attach_state |= PERF_ATTACH_CHILD; 13169 raw_spin_unlock_irqrestore(&child_ctx->lock, flags); 13170 13171 /* 13172 * Link this into the parent event's child list 13173 */ 13174 list_add_tail(&child_event->child_list, &parent_event->child_list); 13175 mutex_unlock(&parent_event->child_mutex); 13176 13177 return child_event; 13178 } 13179 13180 /* 13181 * Inherits an event group. 13182 * 13183 * This will quietly suppress orphaned events; !inherit_event() is not an error. 13184 * This matches with perf_event_release_kernel() removing all child events. 13185 * 13186 * Returns: 13187 * - 0 on success 13188 * - <0 on error 13189 */ 13190 static int inherit_group(struct perf_event *parent_event, 13191 struct task_struct *parent, 13192 struct perf_event_context *parent_ctx, 13193 struct task_struct *child, 13194 struct perf_event_context *child_ctx) 13195 { 13196 struct perf_event *leader; 13197 struct perf_event *sub; 13198 struct perf_event *child_ctr; 13199 13200 leader = inherit_event(parent_event, parent, parent_ctx, 13201 child, NULL, child_ctx); 13202 if (IS_ERR(leader)) 13203 return PTR_ERR(leader); 13204 /* 13205 * @leader can be NULL here because of is_orphaned_event(). In this 13206 * case inherit_event() will create individual events, similar to what 13207 * perf_group_detach() would do anyway. 13208 */ 13209 for_each_sibling_event(sub, parent_event) { 13210 child_ctr = inherit_event(sub, parent, parent_ctx, 13211 child, leader, child_ctx); 13212 if (IS_ERR(child_ctr)) 13213 return PTR_ERR(child_ctr); 13214 13215 if (sub->aux_event == parent_event && child_ctr && 13216 !perf_get_aux_event(child_ctr, leader)) 13217 return -EINVAL; 13218 } 13219 return 0; 13220 } 13221 13222 /* 13223 * Creates the child task context and tries to inherit the event-group. 13224 * 13225 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave 13226 * inherited_all set when we 'fail' to inherit an orphaned event; this is 13227 * consistent with perf_event_release_kernel() removing all child events. 13228 * 13229 * Returns: 13230 * - 0 on success 13231 * - <0 on error 13232 */ 13233 static int 13234 inherit_task_group(struct perf_event *event, struct task_struct *parent, 13235 struct perf_event_context *parent_ctx, 13236 struct task_struct *child, int ctxn, 13237 u64 clone_flags, int *inherited_all) 13238 { 13239 int ret; 13240 struct perf_event_context *child_ctx; 13241 13242 if (!event->attr.inherit || 13243 (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD)) || 13244 /* Do not inherit if sigtrap and signal handlers were cleared. */ 13245 (event->attr.sigtrap && (clone_flags & CLONE_CLEAR_SIGHAND))) { 13246 *inherited_all = 0; 13247 return 0; 13248 } 13249 13250 child_ctx = child->perf_event_ctxp[ctxn]; 13251 if (!child_ctx) { 13252 /* 13253 * This is executed from the parent task context, so 13254 * inherit events that have been marked for cloning. 13255 * First allocate and initialize a context for the 13256 * child. 13257 */ 13258 child_ctx = alloc_perf_context(parent_ctx->pmu, child); 13259 if (!child_ctx) 13260 return -ENOMEM; 13261 13262 child->perf_event_ctxp[ctxn] = child_ctx; 13263 } 13264 13265 ret = inherit_group(event, parent, parent_ctx, 13266 child, child_ctx); 13267 13268 if (ret) 13269 *inherited_all = 0; 13270 13271 return ret; 13272 } 13273 13274 /* 13275 * Initialize the perf_event context in task_struct 13276 */ 13277 static int perf_event_init_context(struct task_struct *child, int ctxn, 13278 u64 clone_flags) 13279 { 13280 struct perf_event_context *child_ctx, *parent_ctx; 13281 struct perf_event_context *cloned_ctx; 13282 struct perf_event *event; 13283 struct task_struct *parent = current; 13284 int inherited_all = 1; 13285 unsigned long flags; 13286 int ret = 0; 13287 13288 if (likely(!parent->perf_event_ctxp[ctxn])) 13289 return 0; 13290 13291 /* 13292 * If the parent's context is a clone, pin it so it won't get 13293 * swapped under us. 13294 */ 13295 parent_ctx = perf_pin_task_context(parent, ctxn); 13296 if (!parent_ctx) 13297 return 0; 13298 13299 /* 13300 * No need to check if parent_ctx != NULL here; since we saw 13301 * it non-NULL earlier, the only reason for it to become NULL 13302 * is if we exit, and since we're currently in the middle of 13303 * a fork we can't be exiting at the same time. 13304 */ 13305 13306 /* 13307 * Lock the parent list. No need to lock the child - not PID 13308 * hashed yet and not running, so nobody can access it. 13309 */ 13310 mutex_lock(&parent_ctx->mutex); 13311 13312 /* 13313 * We dont have to disable NMIs - we are only looking at 13314 * the list, not manipulating it: 13315 */ 13316 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) { 13317 ret = inherit_task_group(event, parent, parent_ctx, 13318 child, ctxn, clone_flags, 13319 &inherited_all); 13320 if (ret) 13321 goto out_unlock; 13322 } 13323 13324 /* 13325 * We can't hold ctx->lock when iterating the ->flexible_group list due 13326 * to allocations, but we need to prevent rotation because 13327 * rotate_ctx() will change the list from interrupt context. 13328 */ 13329 raw_spin_lock_irqsave(&parent_ctx->lock, flags); 13330 parent_ctx->rotate_disable = 1; 13331 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); 13332 13333 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) { 13334 ret = inherit_task_group(event, parent, parent_ctx, 13335 child, ctxn, clone_flags, 13336 &inherited_all); 13337 if (ret) 13338 goto out_unlock; 13339 } 13340 13341 raw_spin_lock_irqsave(&parent_ctx->lock, flags); 13342 parent_ctx->rotate_disable = 0; 13343 13344 child_ctx = child->perf_event_ctxp[ctxn]; 13345 13346 if (child_ctx && inherited_all) { 13347 /* 13348 * Mark the child context as a clone of the parent 13349 * context, or of whatever the parent is a clone of. 13350 * 13351 * Note that if the parent is a clone, the holding of 13352 * parent_ctx->lock avoids it from being uncloned. 13353 */ 13354 cloned_ctx = parent_ctx->parent_ctx; 13355 if (cloned_ctx) { 13356 child_ctx->parent_ctx = cloned_ctx; 13357 child_ctx->parent_gen = parent_ctx->parent_gen; 13358 } else { 13359 child_ctx->parent_ctx = parent_ctx; 13360 child_ctx->parent_gen = parent_ctx->generation; 13361 } 13362 get_ctx(child_ctx->parent_ctx); 13363 } 13364 13365 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); 13366 out_unlock: 13367 mutex_unlock(&parent_ctx->mutex); 13368 13369 perf_unpin_context(parent_ctx); 13370 put_ctx(parent_ctx); 13371 13372 return ret; 13373 } 13374 13375 /* 13376 * Initialize the perf_event context in task_struct 13377 */ 13378 int perf_event_init_task(struct task_struct *child, u64 clone_flags) 13379 { 13380 int ctxn, ret; 13381 13382 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp)); 13383 mutex_init(&child->perf_event_mutex); 13384 INIT_LIST_HEAD(&child->perf_event_list); 13385 13386 for_each_task_context_nr(ctxn) { 13387 ret = perf_event_init_context(child, ctxn, clone_flags); 13388 if (ret) { 13389 perf_event_free_task(child); 13390 return ret; 13391 } 13392 } 13393 13394 return 0; 13395 } 13396 13397 static void __init perf_event_init_all_cpus(void) 13398 { 13399 struct swevent_htable *swhash; 13400 int cpu; 13401 13402 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL); 13403 13404 for_each_possible_cpu(cpu) { 13405 swhash = &per_cpu(swevent_htable, cpu); 13406 mutex_init(&swhash->hlist_mutex); 13407 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu)); 13408 13409 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu)); 13410 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu)); 13411 13412 #ifdef CONFIG_CGROUP_PERF 13413 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu)); 13414 #endif 13415 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu)); 13416 } 13417 } 13418 13419 static void perf_swevent_init_cpu(unsigned int cpu) 13420 { 13421 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu); 13422 13423 mutex_lock(&swhash->hlist_mutex); 13424 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) { 13425 struct swevent_hlist *hlist; 13426 13427 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu)); 13428 WARN_ON(!hlist); 13429 rcu_assign_pointer(swhash->swevent_hlist, hlist); 13430 } 13431 mutex_unlock(&swhash->hlist_mutex); 13432 } 13433 13434 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE 13435 static void __perf_event_exit_context(void *__info) 13436 { 13437 struct perf_event_context *ctx = __info; 13438 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx); 13439 struct perf_event *event; 13440 13441 raw_spin_lock(&ctx->lock); 13442 ctx_sched_out(ctx, cpuctx, EVENT_TIME); 13443 list_for_each_entry(event, &ctx->event_list, event_entry) 13444 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP); 13445 raw_spin_unlock(&ctx->lock); 13446 } 13447 13448 static void perf_event_exit_cpu_context(int cpu) 13449 { 13450 struct perf_cpu_context *cpuctx; 13451 struct perf_event_context *ctx; 13452 struct pmu *pmu; 13453 13454 mutex_lock(&pmus_lock); 13455 list_for_each_entry(pmu, &pmus, entry) { 13456 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 13457 ctx = &cpuctx->ctx; 13458 13459 mutex_lock(&ctx->mutex); 13460 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1); 13461 cpuctx->online = 0; 13462 mutex_unlock(&ctx->mutex); 13463 } 13464 cpumask_clear_cpu(cpu, perf_online_mask); 13465 mutex_unlock(&pmus_lock); 13466 } 13467 #else 13468 13469 static void perf_event_exit_cpu_context(int cpu) { } 13470 13471 #endif 13472 13473 int perf_event_init_cpu(unsigned int cpu) 13474 { 13475 struct perf_cpu_context *cpuctx; 13476 struct perf_event_context *ctx; 13477 struct pmu *pmu; 13478 13479 perf_swevent_init_cpu(cpu); 13480 13481 mutex_lock(&pmus_lock); 13482 cpumask_set_cpu(cpu, perf_online_mask); 13483 list_for_each_entry(pmu, &pmus, entry) { 13484 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu); 13485 ctx = &cpuctx->ctx; 13486 13487 mutex_lock(&ctx->mutex); 13488 cpuctx->online = 1; 13489 mutex_unlock(&ctx->mutex); 13490 } 13491 mutex_unlock(&pmus_lock); 13492 13493 return 0; 13494 } 13495 13496 int perf_event_exit_cpu(unsigned int cpu) 13497 { 13498 perf_event_exit_cpu_context(cpu); 13499 return 0; 13500 } 13501 13502 static int 13503 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v) 13504 { 13505 int cpu; 13506 13507 for_each_online_cpu(cpu) 13508 perf_event_exit_cpu(cpu); 13509 13510 return NOTIFY_OK; 13511 } 13512 13513 /* 13514 * Run the perf reboot notifier at the very last possible moment so that 13515 * the generic watchdog code runs as long as possible. 13516 */ 13517 static struct notifier_block perf_reboot_notifier = { 13518 .notifier_call = perf_reboot, 13519 .priority = INT_MIN, 13520 }; 13521 13522 void __init perf_event_init(void) 13523 { 13524 int ret; 13525 13526 idr_init(&pmu_idr); 13527 13528 perf_event_init_all_cpus(); 13529 init_srcu_struct(&pmus_srcu); 13530 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE); 13531 perf_pmu_register(&perf_cpu_clock, NULL, -1); 13532 perf_pmu_register(&perf_task_clock, NULL, -1); 13533 perf_tp_register(); 13534 perf_event_init_cpu(smp_processor_id()); 13535 register_reboot_notifier(&perf_reboot_notifier); 13536 13537 ret = init_hw_breakpoint(); 13538 WARN(ret, "hw_breakpoint initialization failed with: %d", ret); 13539 13540 perf_event_cache = KMEM_CACHE(perf_event, SLAB_PANIC); 13541 13542 /* 13543 * Build time assertion that we keep the data_head at the intended 13544 * location. IOW, validation we got the __reserved[] size right. 13545 */ 13546 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head)) 13547 != 1024); 13548 } 13549 13550 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr, 13551 char *page) 13552 { 13553 struct perf_pmu_events_attr *pmu_attr = 13554 container_of(attr, struct perf_pmu_events_attr, attr); 13555 13556 if (pmu_attr->event_str) 13557 return sprintf(page, "%s\n", pmu_attr->event_str); 13558 13559 return 0; 13560 } 13561 EXPORT_SYMBOL_GPL(perf_event_sysfs_show); 13562 13563 static int __init perf_event_sysfs_init(void) 13564 { 13565 struct pmu *pmu; 13566 int ret; 13567 13568 mutex_lock(&pmus_lock); 13569 13570 ret = bus_register(&pmu_bus); 13571 if (ret) 13572 goto unlock; 13573 13574 list_for_each_entry(pmu, &pmus, entry) { 13575 if (!pmu->name || pmu->type < 0) 13576 continue; 13577 13578 ret = pmu_dev_alloc(pmu); 13579 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret); 13580 } 13581 pmu_bus_running = 1; 13582 ret = 0; 13583 13584 unlock: 13585 mutex_unlock(&pmus_lock); 13586 13587 return ret; 13588 } 13589 device_initcall(perf_event_sysfs_init); 13590 13591 #ifdef CONFIG_CGROUP_PERF 13592 static struct cgroup_subsys_state * 13593 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) 13594 { 13595 struct perf_cgroup *jc; 13596 13597 jc = kzalloc(sizeof(*jc), GFP_KERNEL); 13598 if (!jc) 13599 return ERR_PTR(-ENOMEM); 13600 13601 jc->info = alloc_percpu(struct perf_cgroup_info); 13602 if (!jc->info) { 13603 kfree(jc); 13604 return ERR_PTR(-ENOMEM); 13605 } 13606 13607 return &jc->css; 13608 } 13609 13610 static void perf_cgroup_css_free(struct cgroup_subsys_state *css) 13611 { 13612 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css); 13613 13614 free_percpu(jc->info); 13615 kfree(jc); 13616 } 13617 13618 static int perf_cgroup_css_online(struct cgroup_subsys_state *css) 13619 { 13620 perf_event_cgroup(css->cgroup); 13621 return 0; 13622 } 13623 13624 static int __perf_cgroup_move(void *info) 13625 { 13626 struct task_struct *task = info; 13627 rcu_read_lock(); 13628 perf_cgroup_switch(task); 13629 rcu_read_unlock(); 13630 return 0; 13631 } 13632 13633 static void perf_cgroup_attach(struct cgroup_taskset *tset) 13634 { 13635 struct task_struct *task; 13636 struct cgroup_subsys_state *css; 13637 13638 cgroup_taskset_for_each(task, css, tset) 13639 task_function_call(task, __perf_cgroup_move, task); 13640 } 13641 13642 struct cgroup_subsys perf_event_cgrp_subsys = { 13643 .css_alloc = perf_cgroup_css_alloc, 13644 .css_free = perf_cgroup_css_free, 13645 .css_online = perf_cgroup_css_online, 13646 .attach = perf_cgroup_attach, 13647 /* 13648 * Implicitly enable on dfl hierarchy so that perf events can 13649 * always be filtered by cgroup2 path as long as perf_event 13650 * controller is not mounted on a legacy hierarchy. 13651 */ 13652 .implicit_on_dfl = true, 13653 .threaded = true, 13654 }; 13655 #endif /* CONFIG_CGROUP_PERF */ 13656 13657 DEFINE_STATIC_CALL_RET0(perf_snapshot_branch_stack, perf_snapshot_branch_stack_t); 13658