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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Performance events core code:
4 *
5 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
6 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
7 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
8 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 */
10
11#include <linux/fs.h>
12#include <linux/mm.h>
13#include <linux/cpu.h>
14#include <linux/smp.h>
15#include <linux/idr.h>
16#include <linux/file.h>
17#include <linux/poll.h>
18#include <linux/slab.h>
19#include <linux/hash.h>
20#include <linux/tick.h>
21#include <linux/sysfs.h>
22#include <linux/dcache.h>
23#include <linux/percpu.h>
24#include <linux/ptrace.h>
25#include <linux/reboot.h>
26#include <linux/vmstat.h>
27#include <linux/device.h>
28#include <linux/export.h>
29#include <linux/vmalloc.h>
30#include <linux/hardirq.h>
31#include <linux/rculist.h>
32#include <linux/uaccess.h>
33#include <linux/syscalls.h>
34#include <linux/anon_inodes.h>
35#include <linux/kernel_stat.h>
36#include <linux/cgroup.h>
37#include <linux/perf_event.h>
38#include <linux/trace_events.h>
39#include <linux/hw_breakpoint.h>
40#include <linux/mm_types.h>
41#include <linux/module.h>
42#include <linux/mman.h>
43#include <linux/compat.h>
44#include <linux/bpf.h>
45#include <linux/filter.h>
46#include <linux/namei.h>
47#include <linux/parser.h>
48#include <linux/sched/clock.h>
49#include <linux/sched/mm.h>
50#include <linux/proc_ns.h>
51#include <linux/mount.h>
52
53#include "internal.h"
54
55#include <asm/irq_regs.h>
56
57typedef int (*remote_function_f)(void *);
58
59struct remote_function_call {
60 struct task_struct *p;
61 remote_function_f func;
62 void *info;
63 int ret;
64};
65
66static void remote_function(void *data)
67{
68 struct remote_function_call *tfc = data;
69 struct task_struct *p = tfc->p;
70
71 if (p) {
72 /* -EAGAIN */
73 if (task_cpu(p) != smp_processor_id())
74 return;
75
76 /*
77 * Now that we're on right CPU with IRQs disabled, we can test
78 * if we hit the right task without races.
79 */
80
81 tfc->ret = -ESRCH; /* No such (running) process */
82 if (p != current)
83 return;
84 }
85
86 tfc->ret = tfc->func(tfc->info);
87}
88
89/**
90 * task_function_call - call a function on the cpu on which a task runs
91 * @p: the task to evaluate
92 * @func: the function to be called
93 * @info: the function call argument
94 *
95 * Calls the function @func when the task is currently running. This might
96 * be on the current CPU, which just calls the function directly
97 *
98 * returns: @func return value, or
99 * -ESRCH - when the process isn't running
100 * -EAGAIN - when the process moved away
101 */
102static int
103task_function_call(struct task_struct *p, remote_function_f func, void *info)
104{
105 struct remote_function_call data = {
106 .p = p,
107 .func = func,
108 .info = info,
109 .ret = -EAGAIN,
110 };
111 int ret;
112
113 do {
114 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1);
115 if (!ret)
116 ret = data.ret;
117 } while (ret == -EAGAIN);
118
119 return ret;
120}
121
122/**
123 * cpu_function_call - call a function on the cpu
124 * @func: the function to be called
125 * @info: the function call argument
126 *
127 * Calls the function @func on the remote cpu.
128 *
129 * returns: @func return value or -ENXIO when the cpu is offline
130 */
131static int cpu_function_call(int cpu, remote_function_f func, void *info)
132{
133 struct remote_function_call data = {
134 .p = NULL,
135 .func = func,
136 .info = info,
137 .ret = -ENXIO, /* No such CPU */
138 };
139
140 smp_call_function_single(cpu, remote_function, &data, 1);
141
142 return data.ret;
143}
144
145static inline struct perf_cpu_context *
146__get_cpu_context(struct perf_event_context *ctx)
147{
148 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
149}
150
151static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
152 struct perf_event_context *ctx)
153{
154 raw_spin_lock(&cpuctx->ctx.lock);
155 if (ctx)
156 raw_spin_lock(&ctx->lock);
157}
158
159static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
160 struct perf_event_context *ctx)
161{
162 if (ctx)
163 raw_spin_unlock(&ctx->lock);
164 raw_spin_unlock(&cpuctx->ctx.lock);
165}
166
167#define TASK_TOMBSTONE ((void *)-1L)
168
169static bool is_kernel_event(struct perf_event *event)
170{
171 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
172}
173
174/*
175 * On task ctx scheduling...
176 *
177 * When !ctx->nr_events a task context will not be scheduled. This means
178 * we can disable the scheduler hooks (for performance) without leaving
179 * pending task ctx state.
180 *
181 * This however results in two special cases:
182 *
183 * - removing the last event from a task ctx; this is relatively straight
184 * forward and is done in __perf_remove_from_context.
185 *
186 * - adding the first event to a task ctx; this is tricky because we cannot
187 * rely on ctx->is_active and therefore cannot use event_function_call().
188 * See perf_install_in_context().
189 *
190 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
191 */
192
193typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
194 struct perf_event_context *, void *);
195
196struct event_function_struct {
197 struct perf_event *event;
198 event_f func;
199 void *data;
200};
201
202static int event_function(void *info)
203{
204 struct event_function_struct *efs = info;
205 struct perf_event *event = efs->event;
206 struct perf_event_context *ctx = event->ctx;
207 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
208 struct perf_event_context *task_ctx = cpuctx->task_ctx;
209 int ret = 0;
210
211 lockdep_assert_irqs_disabled();
212
213 perf_ctx_lock(cpuctx, task_ctx);
214 /*
215 * Since we do the IPI call without holding ctx->lock things can have
216 * changed, double check we hit the task we set out to hit.
217 */
218 if (ctx->task) {
219 if (ctx->task != current) {
220 ret = -ESRCH;
221 goto unlock;
222 }
223
224 /*
225 * We only use event_function_call() on established contexts,
226 * and event_function() is only ever called when active (or
227 * rather, we'll have bailed in task_function_call() or the
228 * above ctx->task != current test), therefore we must have
229 * ctx->is_active here.
230 */
231 WARN_ON_ONCE(!ctx->is_active);
232 /*
233 * And since we have ctx->is_active, cpuctx->task_ctx must
234 * match.
235 */
236 WARN_ON_ONCE(task_ctx != ctx);
237 } else {
238 WARN_ON_ONCE(&cpuctx->ctx != ctx);
239 }
240
241 efs->func(event, cpuctx, ctx, efs->data);
242unlock:
243 perf_ctx_unlock(cpuctx, task_ctx);
244
245 return ret;
246}
247
248static void event_function_call(struct perf_event *event, event_f func, void *data)
249{
250 struct perf_event_context *ctx = event->ctx;
251 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
252 struct event_function_struct efs = {
253 .event = event,
254 .func = func,
255 .data = data,
256 };
257
258 if (!event->parent) {
259 /*
260 * If this is a !child event, we must hold ctx::mutex to
261 * stabilize the the event->ctx relation. See
262 * perf_event_ctx_lock().
263 */
264 lockdep_assert_held(&ctx->mutex);
265 }
266
267 if (!task) {
268 cpu_function_call(event->cpu, event_function, &efs);
269 return;
270 }
271
272 if (task == TASK_TOMBSTONE)
273 return;
274
275again:
276 if (!task_function_call(task, event_function, &efs))
277 return;
278
279 raw_spin_lock_irq(&ctx->lock);
280 /*
281 * Reload the task pointer, it might have been changed by
282 * a concurrent perf_event_context_sched_out().
283 */
284 task = ctx->task;
285 if (task == TASK_TOMBSTONE) {
286 raw_spin_unlock_irq(&ctx->lock);
287 return;
288 }
289 if (ctx->is_active) {
290 raw_spin_unlock_irq(&ctx->lock);
291 goto again;
292 }
293 func(event, NULL, ctx, data);
294 raw_spin_unlock_irq(&ctx->lock);
295}
296
297/*
298 * Similar to event_function_call() + event_function(), but hard assumes IRQs
299 * are already disabled and we're on the right CPU.
300 */
301static void event_function_local(struct perf_event *event, event_f func, void *data)
302{
303 struct perf_event_context *ctx = event->ctx;
304 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
305 struct task_struct *task = READ_ONCE(ctx->task);
306 struct perf_event_context *task_ctx = NULL;
307
308 lockdep_assert_irqs_disabled();
309
310 if (task) {
311 if (task == TASK_TOMBSTONE)
312 return;
313
314 task_ctx = ctx;
315 }
316
317 perf_ctx_lock(cpuctx, task_ctx);
318
319 task = ctx->task;
320 if (task == TASK_TOMBSTONE)
321 goto unlock;
322
323 if (task) {
324 /*
325 * We must be either inactive or active and the right task,
326 * otherwise we're screwed, since we cannot IPI to somewhere
327 * else.
328 */
329 if (ctx->is_active) {
330 if (WARN_ON_ONCE(task != current))
331 goto unlock;
332
333 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
334 goto unlock;
335 }
336 } else {
337 WARN_ON_ONCE(&cpuctx->ctx != ctx);
338 }
339
340 func(event, cpuctx, ctx, data);
341unlock:
342 perf_ctx_unlock(cpuctx, task_ctx);
343}
344
345#define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
346 PERF_FLAG_FD_OUTPUT |\
347 PERF_FLAG_PID_CGROUP |\
348 PERF_FLAG_FD_CLOEXEC)
349
350/*
351 * branch priv levels that need permission checks
352 */
353#define PERF_SAMPLE_BRANCH_PERM_PLM \
354 (PERF_SAMPLE_BRANCH_KERNEL |\
355 PERF_SAMPLE_BRANCH_HV)
356
357enum event_type_t {
358 EVENT_FLEXIBLE = 0x1,
359 EVENT_PINNED = 0x2,
360 EVENT_TIME = 0x4,
361 /* see ctx_resched() for details */
362 EVENT_CPU = 0x8,
363 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
364};
365
366/*
367 * perf_sched_events : >0 events exist
368 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
369 */
370
371static void perf_sched_delayed(struct work_struct *work);
372DEFINE_STATIC_KEY_FALSE(perf_sched_events);
373static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
374static DEFINE_MUTEX(perf_sched_mutex);
375static atomic_t perf_sched_count;
376
377static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
378static DEFINE_PER_CPU(int, perf_sched_cb_usages);
379static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
380
381static atomic_t nr_mmap_events __read_mostly;
382static atomic_t nr_comm_events __read_mostly;
383static atomic_t nr_namespaces_events __read_mostly;
384static atomic_t nr_task_events __read_mostly;
385static atomic_t nr_freq_events __read_mostly;
386static atomic_t nr_switch_events __read_mostly;
387static atomic_t nr_ksymbol_events __read_mostly;
388static atomic_t nr_bpf_events __read_mostly;
389
390static LIST_HEAD(pmus);
391static DEFINE_MUTEX(pmus_lock);
392static struct srcu_struct pmus_srcu;
393static cpumask_var_t perf_online_mask;
394
395/*
396 * perf event paranoia level:
397 * -1 - not paranoid at all
398 * 0 - disallow raw tracepoint access for unpriv
399 * 1 - disallow cpu events for unpriv
400 * 2 - disallow kernel profiling for unpriv
401 */
402int sysctl_perf_event_paranoid __read_mostly = 2;
403
404/* Minimum for 512 kiB + 1 user control page */
405int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
406
407/*
408 * max perf event sample rate
409 */
410#define DEFAULT_MAX_SAMPLE_RATE 100000
411#define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
412#define DEFAULT_CPU_TIME_MAX_PERCENT 25
413
414int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
415
416static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
417static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
418
419static int perf_sample_allowed_ns __read_mostly =
420 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
421
422static void update_perf_cpu_limits(void)
423{
424 u64 tmp = perf_sample_period_ns;
425
426 tmp *= sysctl_perf_cpu_time_max_percent;
427 tmp = div_u64(tmp, 100);
428 if (!tmp)
429 tmp = 1;
430
431 WRITE_ONCE(perf_sample_allowed_ns, tmp);
432}
433
434static bool perf_rotate_context(struct perf_cpu_context *cpuctx);
435
436int perf_proc_update_handler(struct ctl_table *table, int write,
437 void __user *buffer, size_t *lenp,
438 loff_t *ppos)
439{
440 int ret;
441 int perf_cpu = sysctl_perf_cpu_time_max_percent;
442 /*
443 * If throttling is disabled don't allow the write:
444 */
445 if (write && (perf_cpu == 100 || perf_cpu == 0))
446 return -EINVAL;
447
448 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
449 if (ret || !write)
450 return ret;
451
452 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
453 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
454 update_perf_cpu_limits();
455
456 return 0;
457}
458
459int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
460
461int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
462 void __user *buffer, size_t *lenp,
463 loff_t *ppos)
464{
465 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
466
467 if (ret || !write)
468 return ret;
469
470 if (sysctl_perf_cpu_time_max_percent == 100 ||
471 sysctl_perf_cpu_time_max_percent == 0) {
472 printk(KERN_WARNING
473 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
474 WRITE_ONCE(perf_sample_allowed_ns, 0);
475 } else {
476 update_perf_cpu_limits();
477 }
478
479 return 0;
480}
481
482/*
483 * perf samples are done in some very critical code paths (NMIs).
484 * If they take too much CPU time, the system can lock up and not
485 * get any real work done. This will drop the sample rate when
486 * we detect that events are taking too long.
487 */
488#define NR_ACCUMULATED_SAMPLES 128
489static DEFINE_PER_CPU(u64, running_sample_length);
490
491static u64 __report_avg;
492static u64 __report_allowed;
493
494static void perf_duration_warn(struct irq_work *w)
495{
496 printk_ratelimited(KERN_INFO
497 "perf: interrupt took too long (%lld > %lld), lowering "
498 "kernel.perf_event_max_sample_rate to %d\n",
499 __report_avg, __report_allowed,
500 sysctl_perf_event_sample_rate);
501}
502
503static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
504
505void perf_sample_event_took(u64 sample_len_ns)
506{
507 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
508 u64 running_len;
509 u64 avg_len;
510 u32 max;
511
512 if (max_len == 0)
513 return;
514
515 /* Decay the counter by 1 average sample. */
516 running_len = __this_cpu_read(running_sample_length);
517 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
518 running_len += sample_len_ns;
519 __this_cpu_write(running_sample_length, running_len);
520
521 /*
522 * Note: this will be biased artifically low until we have
523 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
524 * from having to maintain a count.
525 */
526 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
527 if (avg_len <= max_len)
528 return;
529
530 __report_avg = avg_len;
531 __report_allowed = max_len;
532
533 /*
534 * Compute a throttle threshold 25% below the current duration.
535 */
536 avg_len += avg_len / 4;
537 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
538 if (avg_len < max)
539 max /= (u32)avg_len;
540 else
541 max = 1;
542
543 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
544 WRITE_ONCE(max_samples_per_tick, max);
545
546 sysctl_perf_event_sample_rate = max * HZ;
547 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
548
549 if (!irq_work_queue(&perf_duration_work)) {
550 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
551 "kernel.perf_event_max_sample_rate to %d\n",
552 __report_avg, __report_allowed,
553 sysctl_perf_event_sample_rate);
554 }
555}
556
557static atomic64_t perf_event_id;
558
559static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
560 enum event_type_t event_type);
561
562static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
563 enum event_type_t event_type,
564 struct task_struct *task);
565
566static void update_context_time(struct perf_event_context *ctx);
567static u64 perf_event_time(struct perf_event *event);
568
569void __weak perf_event_print_debug(void) { }
570
571extern __weak const char *perf_pmu_name(void)
572{
573 return "pmu";
574}
575
576static inline u64 perf_clock(void)
577{
578 return local_clock();
579}
580
581static inline u64 perf_event_clock(struct perf_event *event)
582{
583 return event->clock();
584}
585
586/*
587 * State based event timekeeping...
588 *
589 * The basic idea is to use event->state to determine which (if any) time
590 * fields to increment with the current delta. This means we only need to
591 * update timestamps when we change state or when they are explicitly requested
592 * (read).
593 *
594 * Event groups make things a little more complicated, but not terribly so. The
595 * rules for a group are that if the group leader is OFF the entire group is
596 * OFF, irrespecive of what the group member states are. This results in
597 * __perf_effective_state().
598 *
599 * A futher ramification is that when a group leader flips between OFF and
600 * !OFF, we need to update all group member times.
601 *
602 *
603 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
604 * need to make sure the relevant context time is updated before we try and
605 * update our timestamps.
606 */
607
608static __always_inline enum perf_event_state
609__perf_effective_state(struct perf_event *event)
610{
611 struct perf_event *leader = event->group_leader;
612
613 if (leader->state <= PERF_EVENT_STATE_OFF)
614 return leader->state;
615
616 return event->state;
617}
618
619static __always_inline void
620__perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
621{
622 enum perf_event_state state = __perf_effective_state(event);
623 u64 delta = now - event->tstamp;
624
625 *enabled = event->total_time_enabled;
626 if (state >= PERF_EVENT_STATE_INACTIVE)
627 *enabled += delta;
628
629 *running = event->total_time_running;
630 if (state >= PERF_EVENT_STATE_ACTIVE)
631 *running += delta;
632}
633
634static void perf_event_update_time(struct perf_event *event)
635{
636 u64 now = perf_event_time(event);
637
638 __perf_update_times(event, now, &event->total_time_enabled,
639 &event->total_time_running);
640 event->tstamp = now;
641}
642
643static void perf_event_update_sibling_time(struct perf_event *leader)
644{
645 struct perf_event *sibling;
646
647 for_each_sibling_event(sibling, leader)
648 perf_event_update_time(sibling);
649}
650
651static void
652perf_event_set_state(struct perf_event *event, enum perf_event_state state)
653{
654 if (event->state == state)
655 return;
656
657 perf_event_update_time(event);
658 /*
659 * If a group leader gets enabled/disabled all its siblings
660 * are affected too.
661 */
662 if ((event->state < 0) ^ (state < 0))
663 perf_event_update_sibling_time(event);
664
665 WRITE_ONCE(event->state, state);
666}
667
668#ifdef CONFIG_CGROUP_PERF
669
670static inline bool
671perf_cgroup_match(struct perf_event *event)
672{
673 struct perf_event_context *ctx = event->ctx;
674 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
675
676 /* @event doesn't care about cgroup */
677 if (!event->cgrp)
678 return true;
679
680 /* wants specific cgroup scope but @cpuctx isn't associated with any */
681 if (!cpuctx->cgrp)
682 return false;
683
684 /*
685 * Cgroup scoping is recursive. An event enabled for a cgroup is
686 * also enabled for all its descendant cgroups. If @cpuctx's
687 * cgroup is a descendant of @event's (the test covers identity
688 * case), it's a match.
689 */
690 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
691 event->cgrp->css.cgroup);
692}
693
694static inline void perf_detach_cgroup(struct perf_event *event)
695{
696 css_put(&event->cgrp->css);
697 event->cgrp = NULL;
698}
699
700static inline int is_cgroup_event(struct perf_event *event)
701{
702 return event->cgrp != NULL;
703}
704
705static inline u64 perf_cgroup_event_time(struct perf_event *event)
706{
707 struct perf_cgroup_info *t;
708
709 t = per_cpu_ptr(event->cgrp->info, event->cpu);
710 return t->time;
711}
712
713static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
714{
715 struct perf_cgroup_info *info;
716 u64 now;
717
718 now = perf_clock();
719
720 info = this_cpu_ptr(cgrp->info);
721
722 info->time += now - info->timestamp;
723 info->timestamp = now;
724}
725
726static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
727{
728 struct perf_cgroup *cgrp = cpuctx->cgrp;
729 struct cgroup_subsys_state *css;
730
731 if (cgrp) {
732 for (css = &cgrp->css; css; css = css->parent) {
733 cgrp = container_of(css, struct perf_cgroup, css);
734 __update_cgrp_time(cgrp);
735 }
736 }
737}
738
739static inline void update_cgrp_time_from_event(struct perf_event *event)
740{
741 struct perf_cgroup *cgrp;
742
743 /*
744 * ensure we access cgroup data only when needed and
745 * when we know the cgroup is pinned (css_get)
746 */
747 if (!is_cgroup_event(event))
748 return;
749
750 cgrp = perf_cgroup_from_task(current, event->ctx);
751 /*
752 * Do not update time when cgroup is not active
753 */
754 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
755 __update_cgrp_time(event->cgrp);
756}
757
758static inline void
759perf_cgroup_set_timestamp(struct task_struct *task,
760 struct perf_event_context *ctx)
761{
762 struct perf_cgroup *cgrp;
763 struct perf_cgroup_info *info;
764 struct cgroup_subsys_state *css;
765
766 /*
767 * ctx->lock held by caller
768 * ensure we do not access cgroup data
769 * unless we have the cgroup pinned (css_get)
770 */
771 if (!task || !ctx->nr_cgroups)
772 return;
773
774 cgrp = perf_cgroup_from_task(task, ctx);
775
776 for (css = &cgrp->css; css; css = css->parent) {
777 cgrp = container_of(css, struct perf_cgroup, css);
778 info = this_cpu_ptr(cgrp->info);
779 info->timestamp = ctx->timestamp;
780 }
781}
782
783static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
784
785#define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
786#define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
787
788/*
789 * reschedule events based on the cgroup constraint of task.
790 *
791 * mode SWOUT : schedule out everything
792 * mode SWIN : schedule in based on cgroup for next
793 */
794static void perf_cgroup_switch(struct task_struct *task, int mode)
795{
796 struct perf_cpu_context *cpuctx;
797 struct list_head *list;
798 unsigned long flags;
799
800 /*
801 * Disable interrupts and preemption to avoid this CPU's
802 * cgrp_cpuctx_entry to change under us.
803 */
804 local_irq_save(flags);
805
806 list = this_cpu_ptr(&cgrp_cpuctx_list);
807 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
808 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
809
810 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
811 perf_pmu_disable(cpuctx->ctx.pmu);
812
813 if (mode & PERF_CGROUP_SWOUT) {
814 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
815 /*
816 * must not be done before ctxswout due
817 * to event_filter_match() in event_sched_out()
818 */
819 cpuctx->cgrp = NULL;
820 }
821
822 if (mode & PERF_CGROUP_SWIN) {
823 WARN_ON_ONCE(cpuctx->cgrp);
824 /*
825 * set cgrp before ctxsw in to allow
826 * event_filter_match() to not have to pass
827 * task around
828 * we pass the cpuctx->ctx to perf_cgroup_from_task()
829 * because cgorup events are only per-cpu
830 */
831 cpuctx->cgrp = perf_cgroup_from_task(task,
832 &cpuctx->ctx);
833 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
834 }
835 perf_pmu_enable(cpuctx->ctx.pmu);
836 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
837 }
838
839 local_irq_restore(flags);
840}
841
842static inline void perf_cgroup_sched_out(struct task_struct *task,
843 struct task_struct *next)
844{
845 struct perf_cgroup *cgrp1;
846 struct perf_cgroup *cgrp2 = NULL;
847
848 rcu_read_lock();
849 /*
850 * we come here when we know perf_cgroup_events > 0
851 * we do not need to pass the ctx here because we know
852 * we are holding the rcu lock
853 */
854 cgrp1 = perf_cgroup_from_task(task, NULL);
855 cgrp2 = perf_cgroup_from_task(next, NULL);
856
857 /*
858 * only schedule out current cgroup events if we know
859 * that we are switching to a different cgroup. Otherwise,
860 * do no touch the cgroup events.
861 */
862 if (cgrp1 != cgrp2)
863 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
864
865 rcu_read_unlock();
866}
867
868static inline void perf_cgroup_sched_in(struct task_struct *prev,
869 struct task_struct *task)
870{
871 struct perf_cgroup *cgrp1;
872 struct perf_cgroup *cgrp2 = NULL;
873
874 rcu_read_lock();
875 /*
876 * we come here when we know perf_cgroup_events > 0
877 * we do not need to pass the ctx here because we know
878 * we are holding the rcu lock
879 */
880 cgrp1 = perf_cgroup_from_task(task, NULL);
881 cgrp2 = perf_cgroup_from_task(prev, NULL);
882
883 /*
884 * only need to schedule in cgroup events if we are changing
885 * cgroup during ctxsw. Cgroup events were not scheduled
886 * out of ctxsw out if that was not the case.
887 */
888 if (cgrp1 != cgrp2)
889 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
890
891 rcu_read_unlock();
892}
893
894static inline int perf_cgroup_connect(int fd, struct perf_event *event,
895 struct perf_event_attr *attr,
896 struct perf_event *group_leader)
897{
898 struct perf_cgroup *cgrp;
899 struct cgroup_subsys_state *css;
900 struct fd f = fdget(fd);
901 int ret = 0;
902
903 if (!f.file)
904 return -EBADF;
905
906 css = css_tryget_online_from_dir(f.file->f_path.dentry,
907 &perf_event_cgrp_subsys);
908 if (IS_ERR(css)) {
909 ret = PTR_ERR(css);
910 goto out;
911 }
912
913 cgrp = container_of(css, struct perf_cgroup, css);
914 event->cgrp = cgrp;
915
916 /*
917 * all events in a group must monitor
918 * the same cgroup because a task belongs
919 * to only one perf cgroup at a time
920 */
921 if (group_leader && group_leader->cgrp != cgrp) {
922 perf_detach_cgroup(event);
923 ret = -EINVAL;
924 }
925out:
926 fdput(f);
927 return ret;
928}
929
930static inline void
931perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
932{
933 struct perf_cgroup_info *t;
934 t = per_cpu_ptr(event->cgrp->info, event->cpu);
935 event->shadow_ctx_time = now - t->timestamp;
936}
937
938/*
939 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
940 * cleared when last cgroup event is removed.
941 */
942static inline void
943list_update_cgroup_event(struct perf_event *event,
944 struct perf_event_context *ctx, bool add)
945{
946 struct perf_cpu_context *cpuctx;
947 struct list_head *cpuctx_entry;
948
949 if (!is_cgroup_event(event))
950 return;
951
952 /*
953 * Because cgroup events are always per-cpu events,
954 * this will always be called from the right CPU.
955 */
956 cpuctx = __get_cpu_context(ctx);
957
958 /*
959 * Since setting cpuctx->cgrp is conditional on the current @cgrp
960 * matching the event's cgroup, we must do this for every new event,
961 * because if the first would mismatch, the second would not try again
962 * and we would leave cpuctx->cgrp unset.
963 */
964 if (add && !cpuctx->cgrp) {
965 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
966
967 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
968 cpuctx->cgrp = cgrp;
969 }
970
971 if (add && ctx->nr_cgroups++)
972 return;
973 else if (!add && --ctx->nr_cgroups)
974 return;
975
976 /* no cgroup running */
977 if (!add)
978 cpuctx->cgrp = NULL;
979
980 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
981 if (add)
982 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
983 else
984 list_del(cpuctx_entry);
985}
986
987#else /* !CONFIG_CGROUP_PERF */
988
989static inline bool
990perf_cgroup_match(struct perf_event *event)
991{
992 return true;
993}
994
995static inline void perf_detach_cgroup(struct perf_event *event)
996{}
997
998static inline int is_cgroup_event(struct perf_event *event)
999{
1000 return 0;
1001}
1002
1003static inline void update_cgrp_time_from_event(struct perf_event *event)
1004{
1005}
1006
1007static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
1008{
1009}
1010
1011static inline void perf_cgroup_sched_out(struct task_struct *task,
1012 struct task_struct *next)
1013{
1014}
1015
1016static inline void perf_cgroup_sched_in(struct task_struct *prev,
1017 struct task_struct *task)
1018{
1019}
1020
1021static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1022 struct perf_event_attr *attr,
1023 struct perf_event *group_leader)
1024{
1025 return -EINVAL;
1026}
1027
1028static inline void
1029perf_cgroup_set_timestamp(struct task_struct *task,
1030 struct perf_event_context *ctx)
1031{
1032}
1033
1034static inline void
1035perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1036{
1037}
1038
1039static inline void
1040perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1041{
1042}
1043
1044static inline u64 perf_cgroup_event_time(struct perf_event *event)
1045{
1046 return 0;
1047}
1048
1049static inline void
1050list_update_cgroup_event(struct perf_event *event,
1051 struct perf_event_context *ctx, bool add)
1052{
1053}
1054
1055#endif
1056
1057/*
1058 * set default to be dependent on timer tick just
1059 * like original code
1060 */
1061#define PERF_CPU_HRTIMER (1000 / HZ)
1062/*
1063 * function must be called with interrupts disabled
1064 */
1065static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1066{
1067 struct perf_cpu_context *cpuctx;
1068 bool rotations;
1069
1070 lockdep_assert_irqs_disabled();
1071
1072 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1073 rotations = perf_rotate_context(cpuctx);
1074
1075 raw_spin_lock(&cpuctx->hrtimer_lock);
1076 if (rotations)
1077 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1078 else
1079 cpuctx->hrtimer_active = 0;
1080 raw_spin_unlock(&cpuctx->hrtimer_lock);
1081
1082 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1083}
1084
1085static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1086{
1087 struct hrtimer *timer = &cpuctx->hrtimer;
1088 struct pmu *pmu = cpuctx->ctx.pmu;
1089 u64 interval;
1090
1091 /* no multiplexing needed for SW PMU */
1092 if (pmu->task_ctx_nr == perf_sw_context)
1093 return;
1094
1095 /*
1096 * check default is sane, if not set then force to
1097 * default interval (1/tick)
1098 */
1099 interval = pmu->hrtimer_interval_ms;
1100 if (interval < 1)
1101 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1102
1103 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1104
1105 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1106 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
1107 timer->function = perf_mux_hrtimer_handler;
1108}
1109
1110static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1111{
1112 struct hrtimer *timer = &cpuctx->hrtimer;
1113 struct pmu *pmu = cpuctx->ctx.pmu;
1114 unsigned long flags;
1115
1116 /* not for SW PMU */
1117 if (pmu->task_ctx_nr == perf_sw_context)
1118 return 0;
1119
1120 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1121 if (!cpuctx->hrtimer_active) {
1122 cpuctx->hrtimer_active = 1;
1123 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1124 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
1125 }
1126 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1127
1128 return 0;
1129}
1130
1131void perf_pmu_disable(struct pmu *pmu)
1132{
1133 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1134 if (!(*count)++)
1135 pmu->pmu_disable(pmu);
1136}
1137
1138void perf_pmu_enable(struct pmu *pmu)
1139{
1140 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1141 if (!--(*count))
1142 pmu->pmu_enable(pmu);
1143}
1144
1145static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1146
1147/*
1148 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1149 * perf_event_task_tick() are fully serialized because they're strictly cpu
1150 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1151 * disabled, while perf_event_task_tick is called from IRQ context.
1152 */
1153static void perf_event_ctx_activate(struct perf_event_context *ctx)
1154{
1155 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1156
1157 lockdep_assert_irqs_disabled();
1158
1159 WARN_ON(!list_empty(&ctx->active_ctx_list));
1160
1161 list_add(&ctx->active_ctx_list, head);
1162}
1163
1164static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1165{
1166 lockdep_assert_irqs_disabled();
1167
1168 WARN_ON(list_empty(&ctx->active_ctx_list));
1169
1170 list_del_init(&ctx->active_ctx_list);
1171}
1172
1173static void get_ctx(struct perf_event_context *ctx)
1174{
1175 refcount_inc(&ctx->refcount);
1176}
1177
1178static void free_ctx(struct rcu_head *head)
1179{
1180 struct perf_event_context *ctx;
1181
1182 ctx = container_of(head, struct perf_event_context, rcu_head);
1183 kfree(ctx->task_ctx_data);
1184 kfree(ctx);
1185}
1186
1187static void put_ctx(struct perf_event_context *ctx)
1188{
1189 if (refcount_dec_and_test(&ctx->refcount)) {
1190 if (ctx->parent_ctx)
1191 put_ctx(ctx->parent_ctx);
1192 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1193 put_task_struct(ctx->task);
1194 call_rcu(&ctx->rcu_head, free_ctx);
1195 }
1196}
1197
1198/*
1199 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1200 * perf_pmu_migrate_context() we need some magic.
1201 *
1202 * Those places that change perf_event::ctx will hold both
1203 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1204 *
1205 * Lock ordering is by mutex address. There are two other sites where
1206 * perf_event_context::mutex nests and those are:
1207 *
1208 * - perf_event_exit_task_context() [ child , 0 ]
1209 * perf_event_exit_event()
1210 * put_event() [ parent, 1 ]
1211 *
1212 * - perf_event_init_context() [ parent, 0 ]
1213 * inherit_task_group()
1214 * inherit_group()
1215 * inherit_event()
1216 * perf_event_alloc()
1217 * perf_init_event()
1218 * perf_try_init_event() [ child , 1 ]
1219 *
1220 * While it appears there is an obvious deadlock here -- the parent and child
1221 * nesting levels are inverted between the two. This is in fact safe because
1222 * life-time rules separate them. That is an exiting task cannot fork, and a
1223 * spawning task cannot (yet) exit.
1224 *
1225 * But remember that that these are parent<->child context relations, and
1226 * migration does not affect children, therefore these two orderings should not
1227 * interact.
1228 *
1229 * The change in perf_event::ctx does not affect children (as claimed above)
1230 * because the sys_perf_event_open() case will install a new event and break
1231 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1232 * concerned with cpuctx and that doesn't have children.
1233 *
1234 * The places that change perf_event::ctx will issue:
1235 *
1236 * perf_remove_from_context();
1237 * synchronize_rcu();
1238 * perf_install_in_context();
1239 *
1240 * to affect the change. The remove_from_context() + synchronize_rcu() should
1241 * quiesce the event, after which we can install it in the new location. This
1242 * means that only external vectors (perf_fops, prctl) can perturb the event
1243 * while in transit. Therefore all such accessors should also acquire
1244 * perf_event_context::mutex to serialize against this.
1245 *
1246 * However; because event->ctx can change while we're waiting to acquire
1247 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1248 * function.
1249 *
1250 * Lock order:
1251 * cred_guard_mutex
1252 * task_struct::perf_event_mutex
1253 * perf_event_context::mutex
1254 * perf_event::child_mutex;
1255 * perf_event_context::lock
1256 * perf_event::mmap_mutex
1257 * mmap_sem
1258 * perf_addr_filters_head::lock
1259 *
1260 * cpu_hotplug_lock
1261 * pmus_lock
1262 * cpuctx->mutex / perf_event_context::mutex
1263 */
1264static struct perf_event_context *
1265perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1266{
1267 struct perf_event_context *ctx;
1268
1269again:
1270 rcu_read_lock();
1271 ctx = READ_ONCE(event->ctx);
1272 if (!refcount_inc_not_zero(&ctx->refcount)) {
1273 rcu_read_unlock();
1274 goto again;
1275 }
1276 rcu_read_unlock();
1277
1278 mutex_lock_nested(&ctx->mutex, nesting);
1279 if (event->ctx != ctx) {
1280 mutex_unlock(&ctx->mutex);
1281 put_ctx(ctx);
1282 goto again;
1283 }
1284
1285 return ctx;
1286}
1287
1288static inline struct perf_event_context *
1289perf_event_ctx_lock(struct perf_event *event)
1290{
1291 return perf_event_ctx_lock_nested(event, 0);
1292}
1293
1294static void perf_event_ctx_unlock(struct perf_event *event,
1295 struct perf_event_context *ctx)
1296{
1297 mutex_unlock(&ctx->mutex);
1298 put_ctx(ctx);
1299}
1300
1301/*
1302 * This must be done under the ctx->lock, such as to serialize against
1303 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1304 * calling scheduler related locks and ctx->lock nests inside those.
1305 */
1306static __must_check struct perf_event_context *
1307unclone_ctx(struct perf_event_context *ctx)
1308{
1309 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1310
1311 lockdep_assert_held(&ctx->lock);
1312
1313 if (parent_ctx)
1314 ctx->parent_ctx = NULL;
1315 ctx->generation++;
1316
1317 return parent_ctx;
1318}
1319
1320static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1321 enum pid_type type)
1322{
1323 u32 nr;
1324 /*
1325 * only top level events have the pid namespace they were created in
1326 */
1327 if (event->parent)
1328 event = event->parent;
1329
1330 nr = __task_pid_nr_ns(p, type, event->ns);
1331 /* avoid -1 if it is idle thread or runs in another ns */
1332 if (!nr && !pid_alive(p))
1333 nr = -1;
1334 return nr;
1335}
1336
1337static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1338{
1339 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1340}
1341
1342static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1343{
1344 return perf_event_pid_type(event, p, PIDTYPE_PID);
1345}
1346
1347/*
1348 * If we inherit events we want to return the parent event id
1349 * to userspace.
1350 */
1351static u64 primary_event_id(struct perf_event *event)
1352{
1353 u64 id = event->id;
1354
1355 if (event->parent)
1356 id = event->parent->id;
1357
1358 return id;
1359}
1360
1361/*
1362 * Get the perf_event_context for a task and lock it.
1363 *
1364 * This has to cope with with the fact that until it is locked,
1365 * the context could get moved to another task.
1366 */
1367static struct perf_event_context *
1368perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1369{
1370 struct perf_event_context *ctx;
1371
1372retry:
1373 /*
1374 * One of the few rules of preemptible RCU is that one cannot do
1375 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1376 * part of the read side critical section was irqs-enabled -- see
1377 * rcu_read_unlock_special().
1378 *
1379 * Since ctx->lock nests under rq->lock we must ensure the entire read
1380 * side critical section has interrupts disabled.
1381 */
1382 local_irq_save(*flags);
1383 rcu_read_lock();
1384 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1385 if (ctx) {
1386 /*
1387 * If this context is a clone of another, it might
1388 * get swapped for another underneath us by
1389 * perf_event_task_sched_out, though the
1390 * rcu_read_lock() protects us from any context
1391 * getting freed. Lock the context and check if it
1392 * got swapped before we could get the lock, and retry
1393 * if so. If we locked the right context, then it
1394 * can't get swapped on us any more.
1395 */
1396 raw_spin_lock(&ctx->lock);
1397 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1398 raw_spin_unlock(&ctx->lock);
1399 rcu_read_unlock();
1400 local_irq_restore(*flags);
1401 goto retry;
1402 }
1403
1404 if (ctx->task == TASK_TOMBSTONE ||
1405 !refcount_inc_not_zero(&ctx->refcount)) {
1406 raw_spin_unlock(&ctx->lock);
1407 ctx = NULL;
1408 } else {
1409 WARN_ON_ONCE(ctx->task != task);
1410 }
1411 }
1412 rcu_read_unlock();
1413 if (!ctx)
1414 local_irq_restore(*flags);
1415 return ctx;
1416}
1417
1418/*
1419 * Get the context for a task and increment its pin_count so it
1420 * can't get swapped to another task. This also increments its
1421 * reference count so that the context can't get freed.
1422 */
1423static struct perf_event_context *
1424perf_pin_task_context(struct task_struct *task, int ctxn)
1425{
1426 struct perf_event_context *ctx;
1427 unsigned long flags;
1428
1429 ctx = perf_lock_task_context(task, ctxn, &flags);
1430 if (ctx) {
1431 ++ctx->pin_count;
1432 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1433 }
1434 return ctx;
1435}
1436
1437static void perf_unpin_context(struct perf_event_context *ctx)
1438{
1439 unsigned long flags;
1440
1441 raw_spin_lock_irqsave(&ctx->lock, flags);
1442 --ctx->pin_count;
1443 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1444}
1445
1446/*
1447 * Update the record of the current time in a context.
1448 */
1449static void update_context_time(struct perf_event_context *ctx)
1450{
1451 u64 now = perf_clock();
1452
1453 ctx->time += now - ctx->timestamp;
1454 ctx->timestamp = now;
1455}
1456
1457static u64 perf_event_time(struct perf_event *event)
1458{
1459 struct perf_event_context *ctx = event->ctx;
1460
1461 if (is_cgroup_event(event))
1462 return perf_cgroup_event_time(event);
1463
1464 return ctx ? ctx->time : 0;
1465}
1466
1467static enum event_type_t get_event_type(struct perf_event *event)
1468{
1469 struct perf_event_context *ctx = event->ctx;
1470 enum event_type_t event_type;
1471
1472 lockdep_assert_held(&ctx->lock);
1473
1474 /*
1475 * It's 'group type', really, because if our group leader is
1476 * pinned, so are we.
1477 */
1478 if (event->group_leader != event)
1479 event = event->group_leader;
1480
1481 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1482 if (!ctx->task)
1483 event_type |= EVENT_CPU;
1484
1485 return event_type;
1486}
1487
1488/*
1489 * Helper function to initialize event group nodes.
1490 */
1491static void init_event_group(struct perf_event *event)
1492{
1493 RB_CLEAR_NODE(&event->group_node);
1494 event->group_index = 0;
1495}
1496
1497/*
1498 * Extract pinned or flexible groups from the context
1499 * based on event attrs bits.
1500 */
1501static struct perf_event_groups *
1502get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1503{
1504 if (event->attr.pinned)
1505 return &ctx->pinned_groups;
1506 else
1507 return &ctx->flexible_groups;
1508}
1509
1510/*
1511 * Helper function to initializes perf_event_group trees.
1512 */
1513static void perf_event_groups_init(struct perf_event_groups *groups)
1514{
1515 groups->tree = RB_ROOT;
1516 groups->index = 0;
1517}
1518
1519/*
1520 * Compare function for event groups;
1521 *
1522 * Implements complex key that first sorts by CPU and then by virtual index
1523 * which provides ordering when rotating groups for the same CPU.
1524 */
1525static bool
1526perf_event_groups_less(struct perf_event *left, struct perf_event *right)
1527{
1528 if (left->cpu < right->cpu)
1529 return true;
1530 if (left->cpu > right->cpu)
1531 return false;
1532
1533 if (left->group_index < right->group_index)
1534 return true;
1535 if (left->group_index > right->group_index)
1536 return false;
1537
1538 return false;
1539}
1540
1541/*
1542 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1543 * key (see perf_event_groups_less). This places it last inside the CPU
1544 * subtree.
1545 */
1546static void
1547perf_event_groups_insert(struct perf_event_groups *groups,
1548 struct perf_event *event)
1549{
1550 struct perf_event *node_event;
1551 struct rb_node *parent;
1552 struct rb_node **node;
1553
1554 event->group_index = ++groups->index;
1555
1556 node = &groups->tree.rb_node;
1557 parent = *node;
1558
1559 while (*node) {
1560 parent = *node;
1561 node_event = container_of(*node, struct perf_event, group_node);
1562
1563 if (perf_event_groups_less(event, node_event))
1564 node = &parent->rb_left;
1565 else
1566 node = &parent->rb_right;
1567 }
1568
1569 rb_link_node(&event->group_node, parent, node);
1570 rb_insert_color(&event->group_node, &groups->tree);
1571}
1572
1573/*
1574 * Helper function to insert event into the pinned or flexible groups.
1575 */
1576static void
1577add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1578{
1579 struct perf_event_groups *groups;
1580
1581 groups = get_event_groups(event, ctx);
1582 perf_event_groups_insert(groups, event);
1583}
1584
1585/*
1586 * Delete a group from a tree.
1587 */
1588static void
1589perf_event_groups_delete(struct perf_event_groups *groups,
1590 struct perf_event *event)
1591{
1592 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1593 RB_EMPTY_ROOT(&groups->tree));
1594
1595 rb_erase(&event->group_node, &groups->tree);
1596 init_event_group(event);
1597}
1598
1599/*
1600 * Helper function to delete event from its groups.
1601 */
1602static void
1603del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1604{
1605 struct perf_event_groups *groups;
1606
1607 groups = get_event_groups(event, ctx);
1608 perf_event_groups_delete(groups, event);
1609}
1610
1611/*
1612 * Get the leftmost event in the @cpu subtree.
1613 */
1614static struct perf_event *
1615perf_event_groups_first(struct perf_event_groups *groups, int cpu)
1616{
1617 struct perf_event *node_event = NULL, *match = NULL;
1618 struct rb_node *node = groups->tree.rb_node;
1619
1620 while (node) {
1621 node_event = container_of(node, struct perf_event, group_node);
1622
1623 if (cpu < node_event->cpu) {
1624 node = node->rb_left;
1625 } else if (cpu > node_event->cpu) {
1626 node = node->rb_right;
1627 } else {
1628 match = node_event;
1629 node = node->rb_left;
1630 }
1631 }
1632
1633 return match;
1634}
1635
1636/*
1637 * Like rb_entry_next_safe() for the @cpu subtree.
1638 */
1639static struct perf_event *
1640perf_event_groups_next(struct perf_event *event)
1641{
1642 struct perf_event *next;
1643
1644 next = rb_entry_safe(rb_next(&event->group_node), typeof(*event), group_node);
1645 if (next && next->cpu == event->cpu)
1646 return next;
1647
1648 return NULL;
1649}
1650
1651/*
1652 * Iterate through the whole groups tree.
1653 */
1654#define perf_event_groups_for_each(event, groups) \
1655 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1656 typeof(*event), group_node); event; \
1657 event = rb_entry_safe(rb_next(&event->group_node), \
1658 typeof(*event), group_node))
1659
1660/*
1661 * Add an event from the lists for its context.
1662 * Must be called with ctx->mutex and ctx->lock held.
1663 */
1664static void
1665list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1666{
1667 lockdep_assert_held(&ctx->lock);
1668
1669 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1670 event->attach_state |= PERF_ATTACH_CONTEXT;
1671
1672 event->tstamp = perf_event_time(event);
1673
1674 /*
1675 * If we're a stand alone event or group leader, we go to the context
1676 * list, group events are kept attached to the group so that
1677 * perf_group_detach can, at all times, locate all siblings.
1678 */
1679 if (event->group_leader == event) {
1680 event->group_caps = event->event_caps;
1681 add_event_to_groups(event, ctx);
1682 }
1683
1684 list_update_cgroup_event(event, ctx, true);
1685
1686 list_add_rcu(&event->event_entry, &ctx->event_list);
1687 ctx->nr_events++;
1688 if (event->attr.inherit_stat)
1689 ctx->nr_stat++;
1690
1691 ctx->generation++;
1692}
1693
1694/*
1695 * Initialize event state based on the perf_event_attr::disabled.
1696 */
1697static inline void perf_event__state_init(struct perf_event *event)
1698{
1699 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1700 PERF_EVENT_STATE_INACTIVE;
1701}
1702
1703static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1704{
1705 int entry = sizeof(u64); /* value */
1706 int size = 0;
1707 int nr = 1;
1708
1709 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1710 size += sizeof(u64);
1711
1712 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1713 size += sizeof(u64);
1714
1715 if (event->attr.read_format & PERF_FORMAT_ID)
1716 entry += sizeof(u64);
1717
1718 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1719 nr += nr_siblings;
1720 size += sizeof(u64);
1721 }
1722
1723 size += entry * nr;
1724 event->read_size = size;
1725}
1726
1727static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1728{
1729 struct perf_sample_data *data;
1730 u16 size = 0;
1731
1732 if (sample_type & PERF_SAMPLE_IP)
1733 size += sizeof(data->ip);
1734
1735 if (sample_type & PERF_SAMPLE_ADDR)
1736 size += sizeof(data->addr);
1737
1738 if (sample_type & PERF_SAMPLE_PERIOD)
1739 size += sizeof(data->period);
1740
1741 if (sample_type & PERF_SAMPLE_WEIGHT)
1742 size += sizeof(data->weight);
1743
1744 if (sample_type & PERF_SAMPLE_READ)
1745 size += event->read_size;
1746
1747 if (sample_type & PERF_SAMPLE_DATA_SRC)
1748 size += sizeof(data->data_src.val);
1749
1750 if (sample_type & PERF_SAMPLE_TRANSACTION)
1751 size += sizeof(data->txn);
1752
1753 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1754 size += sizeof(data->phys_addr);
1755
1756 event->header_size = size;
1757}
1758
1759/*
1760 * Called at perf_event creation and when events are attached/detached from a
1761 * group.
1762 */
1763static void perf_event__header_size(struct perf_event *event)
1764{
1765 __perf_event_read_size(event,
1766 event->group_leader->nr_siblings);
1767 __perf_event_header_size(event, event->attr.sample_type);
1768}
1769
1770static void perf_event__id_header_size(struct perf_event *event)
1771{
1772 struct perf_sample_data *data;
1773 u64 sample_type = event->attr.sample_type;
1774 u16 size = 0;
1775
1776 if (sample_type & PERF_SAMPLE_TID)
1777 size += sizeof(data->tid_entry);
1778
1779 if (sample_type & PERF_SAMPLE_TIME)
1780 size += sizeof(data->time);
1781
1782 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1783 size += sizeof(data->id);
1784
1785 if (sample_type & PERF_SAMPLE_ID)
1786 size += sizeof(data->id);
1787
1788 if (sample_type & PERF_SAMPLE_STREAM_ID)
1789 size += sizeof(data->stream_id);
1790
1791 if (sample_type & PERF_SAMPLE_CPU)
1792 size += sizeof(data->cpu_entry);
1793
1794 event->id_header_size = size;
1795}
1796
1797static bool perf_event_validate_size(struct perf_event *event)
1798{
1799 /*
1800 * The values computed here will be over-written when we actually
1801 * attach the event.
1802 */
1803 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1804 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1805 perf_event__id_header_size(event);
1806
1807 /*
1808 * Sum the lot; should not exceed the 64k limit we have on records.
1809 * Conservative limit to allow for callchains and other variable fields.
1810 */
1811 if (event->read_size + event->header_size +
1812 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1813 return false;
1814
1815 return true;
1816}
1817
1818static void perf_group_attach(struct perf_event *event)
1819{
1820 struct perf_event *group_leader = event->group_leader, *pos;
1821
1822 lockdep_assert_held(&event->ctx->lock);
1823
1824 /*
1825 * We can have double attach due to group movement in perf_event_open.
1826 */
1827 if (event->attach_state & PERF_ATTACH_GROUP)
1828 return;
1829
1830 event->attach_state |= PERF_ATTACH_GROUP;
1831
1832 if (group_leader == event)
1833 return;
1834
1835 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1836
1837 group_leader->group_caps &= event->event_caps;
1838
1839 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1840 group_leader->nr_siblings++;
1841
1842 perf_event__header_size(group_leader);
1843
1844 for_each_sibling_event(pos, group_leader)
1845 perf_event__header_size(pos);
1846}
1847
1848/*
1849 * Remove an event from the lists for its context.
1850 * Must be called with ctx->mutex and ctx->lock held.
1851 */
1852static void
1853list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1854{
1855 WARN_ON_ONCE(event->ctx != ctx);
1856 lockdep_assert_held(&ctx->lock);
1857
1858 /*
1859 * We can have double detach due to exit/hot-unplug + close.
1860 */
1861 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1862 return;
1863
1864 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1865
1866 list_update_cgroup_event(event, ctx, false);
1867
1868 ctx->nr_events--;
1869 if (event->attr.inherit_stat)
1870 ctx->nr_stat--;
1871
1872 list_del_rcu(&event->event_entry);
1873
1874 if (event->group_leader == event)
1875 del_event_from_groups(event, ctx);
1876
1877 /*
1878 * If event was in error state, then keep it
1879 * that way, otherwise bogus counts will be
1880 * returned on read(). The only way to get out
1881 * of error state is by explicit re-enabling
1882 * of the event
1883 */
1884 if (event->state > PERF_EVENT_STATE_OFF)
1885 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1886
1887 ctx->generation++;
1888}
1889
1890static int
1891perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
1892{
1893 if (!has_aux(aux_event))
1894 return 0;
1895
1896 if (!event->pmu->aux_output_match)
1897 return 0;
1898
1899 return event->pmu->aux_output_match(aux_event);
1900}
1901
1902static void put_event(struct perf_event *event);
1903static void event_sched_out(struct perf_event *event,
1904 struct perf_cpu_context *cpuctx,
1905 struct perf_event_context *ctx);
1906
1907static void perf_put_aux_event(struct perf_event *event)
1908{
1909 struct perf_event_context *ctx = event->ctx;
1910 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1911 struct perf_event *iter;
1912
1913 /*
1914 * If event uses aux_event tear down the link
1915 */
1916 if (event->aux_event) {
1917 iter = event->aux_event;
1918 event->aux_event = NULL;
1919 put_event(iter);
1920 return;
1921 }
1922
1923 /*
1924 * If the event is an aux_event, tear down all links to
1925 * it from other events.
1926 */
1927 for_each_sibling_event(iter, event->group_leader) {
1928 if (iter->aux_event != event)
1929 continue;
1930
1931 iter->aux_event = NULL;
1932 put_event(event);
1933
1934 /*
1935 * If it's ACTIVE, schedule it out and put it into ERROR
1936 * state so that we don't try to schedule it again. Note
1937 * that perf_event_enable() will clear the ERROR status.
1938 */
1939 event_sched_out(iter, cpuctx, ctx);
1940 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
1941 }
1942}
1943
1944static int perf_get_aux_event(struct perf_event *event,
1945 struct perf_event *group_leader)
1946{
1947 /*
1948 * Our group leader must be an aux event if we want to be
1949 * an aux_output. This way, the aux event will precede its
1950 * aux_output events in the group, and therefore will always
1951 * schedule first.
1952 */
1953 if (!group_leader)
1954 return 0;
1955
1956 if (!perf_aux_output_match(event, group_leader))
1957 return 0;
1958
1959 if (!atomic_long_inc_not_zero(&group_leader->refcount))
1960 return 0;
1961
1962 /*
1963 * Link aux_outputs to their aux event; this is undone in
1964 * perf_group_detach() by perf_put_aux_event(). When the
1965 * group in torn down, the aux_output events loose their
1966 * link to the aux_event and can't schedule any more.
1967 */
1968 event->aux_event = group_leader;
1969
1970 return 1;
1971}
1972
1973static void perf_group_detach(struct perf_event *event)
1974{
1975 struct perf_event *sibling, *tmp;
1976 struct perf_event_context *ctx = event->ctx;
1977
1978 lockdep_assert_held(&ctx->lock);
1979
1980 /*
1981 * We can have double detach due to exit/hot-unplug + close.
1982 */
1983 if (!(event->attach_state & PERF_ATTACH_GROUP))
1984 return;
1985
1986 event->attach_state &= ~PERF_ATTACH_GROUP;
1987
1988 perf_put_aux_event(event);
1989
1990 /*
1991 * If this is a sibling, remove it from its group.
1992 */
1993 if (event->group_leader != event) {
1994 list_del_init(&event->sibling_list);
1995 event->group_leader->nr_siblings--;
1996 goto out;
1997 }
1998
1999 /*
2000 * If this was a group event with sibling events then
2001 * upgrade the siblings to singleton events by adding them
2002 * to whatever list we are on.
2003 */
2004 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
2005
2006 sibling->group_leader = sibling;
2007 list_del_init(&sibling->sibling_list);
2008
2009 /* Inherit group flags from the previous leader */
2010 sibling->group_caps = event->group_caps;
2011
2012 if (!RB_EMPTY_NODE(&event->group_node)) {
2013 add_event_to_groups(sibling, event->ctx);
2014
2015 if (sibling->state == PERF_EVENT_STATE_ACTIVE) {
2016 struct list_head *list = sibling->attr.pinned ?
2017 &ctx->pinned_active : &ctx->flexible_active;
2018
2019 list_add_tail(&sibling->active_list, list);
2020 }
2021 }
2022
2023 WARN_ON_ONCE(sibling->ctx != event->ctx);
2024 }
2025
2026out:
2027 perf_event__header_size(event->group_leader);
2028
2029 for_each_sibling_event(tmp, event->group_leader)
2030 perf_event__header_size(tmp);
2031}
2032
2033static bool is_orphaned_event(struct perf_event *event)
2034{
2035 return event->state == PERF_EVENT_STATE_DEAD;
2036}
2037
2038static inline int __pmu_filter_match(struct perf_event *event)
2039{
2040 struct pmu *pmu = event->pmu;
2041 return pmu->filter_match ? pmu->filter_match(event) : 1;
2042}
2043
2044/*
2045 * Check whether we should attempt to schedule an event group based on
2046 * PMU-specific filtering. An event group can consist of HW and SW events,
2047 * potentially with a SW leader, so we must check all the filters, to
2048 * determine whether a group is schedulable:
2049 */
2050static inline int pmu_filter_match(struct perf_event *event)
2051{
2052 struct perf_event *sibling;
2053
2054 if (!__pmu_filter_match(event))
2055 return 0;
2056
2057 for_each_sibling_event(sibling, event) {
2058 if (!__pmu_filter_match(sibling))
2059 return 0;
2060 }
2061
2062 return 1;
2063}
2064
2065static inline int
2066event_filter_match(struct perf_event *event)
2067{
2068 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2069 perf_cgroup_match(event) && pmu_filter_match(event);
2070}
2071
2072static void
2073event_sched_out(struct perf_event *event,
2074 struct perf_cpu_context *cpuctx,
2075 struct perf_event_context *ctx)
2076{
2077 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2078
2079 WARN_ON_ONCE(event->ctx != ctx);
2080 lockdep_assert_held(&ctx->lock);
2081
2082 if (event->state != PERF_EVENT_STATE_ACTIVE)
2083 return;
2084
2085 /*
2086 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2087 * we can schedule events _OUT_ individually through things like
2088 * __perf_remove_from_context().
2089 */
2090 list_del_init(&event->active_list);
2091
2092 perf_pmu_disable(event->pmu);
2093
2094 event->pmu->del(event, 0);
2095 event->oncpu = -1;
2096
2097 if (READ_ONCE(event->pending_disable) >= 0) {
2098 WRITE_ONCE(event->pending_disable, -1);
2099 state = PERF_EVENT_STATE_OFF;
2100 }
2101 perf_event_set_state(event, state);
2102
2103 if (!is_software_event(event))
2104 cpuctx->active_oncpu--;
2105 if (!--ctx->nr_active)
2106 perf_event_ctx_deactivate(ctx);
2107 if (event->attr.freq && event->attr.sample_freq)
2108 ctx->nr_freq--;
2109 if (event->attr.exclusive || !cpuctx->active_oncpu)
2110 cpuctx->exclusive = 0;
2111
2112 perf_pmu_enable(event->pmu);
2113}
2114
2115static void
2116group_sched_out(struct perf_event *group_event,
2117 struct perf_cpu_context *cpuctx,
2118 struct perf_event_context *ctx)
2119{
2120 struct perf_event *event;
2121
2122 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2123 return;
2124
2125 perf_pmu_disable(ctx->pmu);
2126
2127 event_sched_out(group_event, cpuctx, ctx);
2128
2129 /*
2130 * Schedule out siblings (if any):
2131 */
2132 for_each_sibling_event(event, group_event)
2133 event_sched_out(event, cpuctx, ctx);
2134
2135 perf_pmu_enable(ctx->pmu);
2136
2137 if (group_event->attr.exclusive)
2138 cpuctx->exclusive = 0;
2139}
2140
2141#define DETACH_GROUP 0x01UL
2142
2143/*
2144 * Cross CPU call to remove a performance event
2145 *
2146 * We disable the event on the hardware level first. After that we
2147 * remove it from the context list.
2148 */
2149static void
2150__perf_remove_from_context(struct perf_event *event,
2151 struct perf_cpu_context *cpuctx,
2152 struct perf_event_context *ctx,
2153 void *info)
2154{
2155 unsigned long flags = (unsigned long)info;
2156
2157 if (ctx->is_active & EVENT_TIME) {
2158 update_context_time(ctx);
2159 update_cgrp_time_from_cpuctx(cpuctx);
2160 }
2161
2162 event_sched_out(event, cpuctx, ctx);
2163 if (flags & DETACH_GROUP)
2164 perf_group_detach(event);
2165 list_del_event(event, ctx);
2166
2167 if (!ctx->nr_events && ctx->is_active) {
2168 ctx->is_active = 0;
2169 if (ctx->task) {
2170 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2171 cpuctx->task_ctx = NULL;
2172 }
2173 }
2174}
2175
2176/*
2177 * Remove the event from a task's (or a CPU's) list of events.
2178 *
2179 * If event->ctx is a cloned context, callers must make sure that
2180 * every task struct that event->ctx->task could possibly point to
2181 * remains valid. This is OK when called from perf_release since
2182 * that only calls us on the top-level context, which can't be a clone.
2183 * When called from perf_event_exit_task, it's OK because the
2184 * context has been detached from its task.
2185 */
2186static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2187{
2188 struct perf_event_context *ctx = event->ctx;
2189
2190 lockdep_assert_held(&ctx->mutex);
2191
2192 event_function_call(event, __perf_remove_from_context, (void *)flags);
2193
2194 /*
2195 * The above event_function_call() can NO-OP when it hits
2196 * TASK_TOMBSTONE. In that case we must already have been detached
2197 * from the context (by perf_event_exit_event()) but the grouping
2198 * might still be in-tact.
2199 */
2200 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
2201 if ((flags & DETACH_GROUP) &&
2202 (event->attach_state & PERF_ATTACH_GROUP)) {
2203 /*
2204 * Since in that case we cannot possibly be scheduled, simply
2205 * detach now.
2206 */
2207 raw_spin_lock_irq(&ctx->lock);
2208 perf_group_detach(event);
2209 raw_spin_unlock_irq(&ctx->lock);
2210 }
2211}
2212
2213/*
2214 * Cross CPU call to disable a performance event
2215 */
2216static void __perf_event_disable(struct perf_event *event,
2217 struct perf_cpu_context *cpuctx,
2218 struct perf_event_context *ctx,
2219 void *info)
2220{
2221 if (event->state < PERF_EVENT_STATE_INACTIVE)
2222 return;
2223
2224 if (ctx->is_active & EVENT_TIME) {
2225 update_context_time(ctx);
2226 update_cgrp_time_from_event(event);
2227 }
2228
2229 if (event == event->group_leader)
2230 group_sched_out(event, cpuctx, ctx);
2231 else
2232 event_sched_out(event, cpuctx, ctx);
2233
2234 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2235}
2236
2237/*
2238 * Disable an event.
2239 *
2240 * If event->ctx is a cloned context, callers must make sure that
2241 * every task struct that event->ctx->task could possibly point to
2242 * remains valid. This condition is satisfied when called through
2243 * perf_event_for_each_child or perf_event_for_each because they
2244 * hold the top-level event's child_mutex, so any descendant that
2245 * goes to exit will block in perf_event_exit_event().
2246 *
2247 * When called from perf_pending_event it's OK because event->ctx
2248 * is the current context on this CPU and preemption is disabled,
2249 * hence we can't get into perf_event_task_sched_out for this context.
2250 */
2251static void _perf_event_disable(struct perf_event *event)
2252{
2253 struct perf_event_context *ctx = event->ctx;
2254
2255 raw_spin_lock_irq(&ctx->lock);
2256 if (event->state <= PERF_EVENT_STATE_OFF) {
2257 raw_spin_unlock_irq(&ctx->lock);
2258 return;
2259 }
2260 raw_spin_unlock_irq(&ctx->lock);
2261
2262 event_function_call(event, __perf_event_disable, NULL);
2263}
2264
2265void perf_event_disable_local(struct perf_event *event)
2266{
2267 event_function_local(event, __perf_event_disable, NULL);
2268}
2269
2270/*
2271 * Strictly speaking kernel users cannot create groups and therefore this
2272 * interface does not need the perf_event_ctx_lock() magic.
2273 */
2274void perf_event_disable(struct perf_event *event)
2275{
2276 struct perf_event_context *ctx;
2277
2278 ctx = perf_event_ctx_lock(event);
2279 _perf_event_disable(event);
2280 perf_event_ctx_unlock(event, ctx);
2281}
2282EXPORT_SYMBOL_GPL(perf_event_disable);
2283
2284void perf_event_disable_inatomic(struct perf_event *event)
2285{
2286 WRITE_ONCE(event->pending_disable, smp_processor_id());
2287 /* can fail, see perf_pending_event_disable() */
2288 irq_work_queue(&event->pending);
2289}
2290
2291static void perf_set_shadow_time(struct perf_event *event,
2292 struct perf_event_context *ctx)
2293{
2294 /*
2295 * use the correct time source for the time snapshot
2296 *
2297 * We could get by without this by leveraging the
2298 * fact that to get to this function, the caller
2299 * has most likely already called update_context_time()
2300 * and update_cgrp_time_xx() and thus both timestamp
2301 * are identical (or very close). Given that tstamp is,
2302 * already adjusted for cgroup, we could say that:
2303 * tstamp - ctx->timestamp
2304 * is equivalent to
2305 * tstamp - cgrp->timestamp.
2306 *
2307 * Then, in perf_output_read(), the calculation would
2308 * work with no changes because:
2309 * - event is guaranteed scheduled in
2310 * - no scheduled out in between
2311 * - thus the timestamp would be the same
2312 *
2313 * But this is a bit hairy.
2314 *
2315 * So instead, we have an explicit cgroup call to remain
2316 * within the time time source all along. We believe it
2317 * is cleaner and simpler to understand.
2318 */
2319 if (is_cgroup_event(event))
2320 perf_cgroup_set_shadow_time(event, event->tstamp);
2321 else
2322 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2323}
2324
2325#define MAX_INTERRUPTS (~0ULL)
2326
2327static void perf_log_throttle(struct perf_event *event, int enable);
2328static void perf_log_itrace_start(struct perf_event *event);
2329
2330static int
2331event_sched_in(struct perf_event *event,
2332 struct perf_cpu_context *cpuctx,
2333 struct perf_event_context *ctx)
2334{
2335 int ret = 0;
2336
2337 lockdep_assert_held(&ctx->lock);
2338
2339 if (event->state <= PERF_EVENT_STATE_OFF)
2340 return 0;
2341
2342 WRITE_ONCE(event->oncpu, smp_processor_id());
2343 /*
2344 * Order event::oncpu write to happen before the ACTIVE state is
2345 * visible. This allows perf_event_{stop,read}() to observe the correct
2346 * ->oncpu if it sees ACTIVE.
2347 */
2348 smp_wmb();
2349 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2350
2351 /*
2352 * Unthrottle events, since we scheduled we might have missed several
2353 * ticks already, also for a heavily scheduling task there is little
2354 * guarantee it'll get a tick in a timely manner.
2355 */
2356 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2357 perf_log_throttle(event, 1);
2358 event->hw.interrupts = 0;
2359 }
2360
2361 perf_pmu_disable(event->pmu);
2362
2363 perf_set_shadow_time(event, ctx);
2364
2365 perf_log_itrace_start(event);
2366
2367 if (event->pmu->add(event, PERF_EF_START)) {
2368 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2369 event->oncpu = -1;
2370 ret = -EAGAIN;
2371 goto out;
2372 }
2373
2374 if (!is_software_event(event))
2375 cpuctx->active_oncpu++;
2376 if (!ctx->nr_active++)
2377 perf_event_ctx_activate(ctx);
2378 if (event->attr.freq && event->attr.sample_freq)
2379 ctx->nr_freq++;
2380
2381 if (event->attr.exclusive)
2382 cpuctx->exclusive = 1;
2383
2384out:
2385 perf_pmu_enable(event->pmu);
2386
2387 return ret;
2388}
2389
2390static int
2391group_sched_in(struct perf_event *group_event,
2392 struct perf_cpu_context *cpuctx,
2393 struct perf_event_context *ctx)
2394{
2395 struct perf_event *event, *partial_group = NULL;
2396 struct pmu *pmu = ctx->pmu;
2397
2398 if (group_event->state == PERF_EVENT_STATE_OFF)
2399 return 0;
2400
2401 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2402
2403 if (event_sched_in(group_event, cpuctx, ctx)) {
2404 pmu->cancel_txn(pmu);
2405 perf_mux_hrtimer_restart(cpuctx);
2406 return -EAGAIN;
2407 }
2408
2409 /*
2410 * Schedule in siblings as one group (if any):
2411 */
2412 for_each_sibling_event(event, group_event) {
2413 if (event_sched_in(event, cpuctx, ctx)) {
2414 partial_group = event;
2415 goto group_error;
2416 }
2417 }
2418
2419 if (!pmu->commit_txn(pmu))
2420 return 0;
2421
2422group_error:
2423 /*
2424 * Groups can be scheduled in as one unit only, so undo any
2425 * partial group before returning:
2426 * The events up to the failed event are scheduled out normally.
2427 */
2428 for_each_sibling_event(event, group_event) {
2429 if (event == partial_group)
2430 break;
2431
2432 event_sched_out(event, cpuctx, ctx);
2433 }
2434 event_sched_out(group_event, cpuctx, ctx);
2435
2436 pmu->cancel_txn(pmu);
2437
2438 perf_mux_hrtimer_restart(cpuctx);
2439
2440 return -EAGAIN;
2441}
2442
2443/*
2444 * Work out whether we can put this event group on the CPU now.
2445 */
2446static int group_can_go_on(struct perf_event *event,
2447 struct perf_cpu_context *cpuctx,
2448 int can_add_hw)
2449{
2450 /*
2451 * Groups consisting entirely of software events can always go on.
2452 */
2453 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2454 return 1;
2455 /*
2456 * If an exclusive group is already on, no other hardware
2457 * events can go on.
2458 */
2459 if (cpuctx->exclusive)
2460 return 0;
2461 /*
2462 * If this group is exclusive and there are already
2463 * events on the CPU, it can't go on.
2464 */
2465 if (event->attr.exclusive && cpuctx->active_oncpu)
2466 return 0;
2467 /*
2468 * Otherwise, try to add it if all previous groups were able
2469 * to go on.
2470 */
2471 return can_add_hw;
2472}
2473
2474static void add_event_to_ctx(struct perf_event *event,
2475 struct perf_event_context *ctx)
2476{
2477 list_add_event(event, ctx);
2478 perf_group_attach(event);
2479}
2480
2481static void ctx_sched_out(struct perf_event_context *ctx,
2482 struct perf_cpu_context *cpuctx,
2483 enum event_type_t event_type);
2484static void
2485ctx_sched_in(struct perf_event_context *ctx,
2486 struct perf_cpu_context *cpuctx,
2487 enum event_type_t event_type,
2488 struct task_struct *task);
2489
2490static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2491 struct perf_event_context *ctx,
2492 enum event_type_t event_type)
2493{
2494 if (!cpuctx->task_ctx)
2495 return;
2496
2497 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2498 return;
2499
2500 ctx_sched_out(ctx, cpuctx, event_type);
2501}
2502
2503static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2504 struct perf_event_context *ctx,
2505 struct task_struct *task)
2506{
2507 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2508 if (ctx)
2509 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2510 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2511 if (ctx)
2512 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2513}
2514
2515/*
2516 * We want to maintain the following priority of scheduling:
2517 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2518 * - task pinned (EVENT_PINNED)
2519 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2520 * - task flexible (EVENT_FLEXIBLE).
2521 *
2522 * In order to avoid unscheduling and scheduling back in everything every
2523 * time an event is added, only do it for the groups of equal priority and
2524 * below.
2525 *
2526 * This can be called after a batch operation on task events, in which case
2527 * event_type is a bit mask of the types of events involved. For CPU events,
2528 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2529 */
2530static void ctx_resched(struct perf_cpu_context *cpuctx,
2531 struct perf_event_context *task_ctx,
2532 enum event_type_t event_type)
2533{
2534 enum event_type_t ctx_event_type;
2535 bool cpu_event = !!(event_type & EVENT_CPU);
2536
2537 /*
2538 * If pinned groups are involved, flexible groups also need to be
2539 * scheduled out.
2540 */
2541 if (event_type & EVENT_PINNED)
2542 event_type |= EVENT_FLEXIBLE;
2543
2544 ctx_event_type = event_type & EVENT_ALL;
2545
2546 perf_pmu_disable(cpuctx->ctx.pmu);
2547 if (task_ctx)
2548 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2549
2550 /*
2551 * Decide which cpu ctx groups to schedule out based on the types
2552 * of events that caused rescheduling:
2553 * - EVENT_CPU: schedule out corresponding groups;
2554 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2555 * - otherwise, do nothing more.
2556 */
2557 if (cpu_event)
2558 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2559 else if (ctx_event_type & EVENT_PINNED)
2560 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2561
2562 perf_event_sched_in(cpuctx, task_ctx, current);
2563 perf_pmu_enable(cpuctx->ctx.pmu);
2564}
2565
2566void perf_pmu_resched(struct pmu *pmu)
2567{
2568 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2569 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2570
2571 perf_ctx_lock(cpuctx, task_ctx);
2572 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2573 perf_ctx_unlock(cpuctx, task_ctx);
2574}
2575
2576/*
2577 * Cross CPU call to install and enable a performance event
2578 *
2579 * Very similar to remote_function() + event_function() but cannot assume that
2580 * things like ctx->is_active and cpuctx->task_ctx are set.
2581 */
2582static int __perf_install_in_context(void *info)
2583{
2584 struct perf_event *event = info;
2585 struct perf_event_context *ctx = event->ctx;
2586 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2587 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2588 bool reprogram = true;
2589 int ret = 0;
2590
2591 raw_spin_lock(&cpuctx->ctx.lock);
2592 if (ctx->task) {
2593 raw_spin_lock(&ctx->lock);
2594 task_ctx = ctx;
2595
2596 reprogram = (ctx->task == current);
2597
2598 /*
2599 * If the task is running, it must be running on this CPU,
2600 * otherwise we cannot reprogram things.
2601 *
2602 * If its not running, we don't care, ctx->lock will
2603 * serialize against it becoming runnable.
2604 */
2605 if (task_curr(ctx->task) && !reprogram) {
2606 ret = -ESRCH;
2607 goto unlock;
2608 }
2609
2610 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2611 } else if (task_ctx) {
2612 raw_spin_lock(&task_ctx->lock);
2613 }
2614
2615#ifdef CONFIG_CGROUP_PERF
2616 if (is_cgroup_event(event)) {
2617 /*
2618 * If the current cgroup doesn't match the event's
2619 * cgroup, we should not try to schedule it.
2620 */
2621 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2622 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2623 event->cgrp->css.cgroup);
2624 }
2625#endif
2626
2627 if (reprogram) {
2628 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2629 add_event_to_ctx(event, ctx);
2630 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2631 } else {
2632 add_event_to_ctx(event, ctx);
2633 }
2634
2635unlock:
2636 perf_ctx_unlock(cpuctx, task_ctx);
2637
2638 return ret;
2639}
2640
2641static bool exclusive_event_installable(struct perf_event *event,
2642 struct perf_event_context *ctx);
2643
2644/*
2645 * Attach a performance event to a context.
2646 *
2647 * Very similar to event_function_call, see comment there.
2648 */
2649static void
2650perf_install_in_context(struct perf_event_context *ctx,
2651 struct perf_event *event,
2652 int cpu)
2653{
2654 struct task_struct *task = READ_ONCE(ctx->task);
2655
2656 lockdep_assert_held(&ctx->mutex);
2657
2658 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2659
2660 if (event->cpu != -1)
2661 event->cpu = cpu;
2662
2663 /*
2664 * Ensures that if we can observe event->ctx, both the event and ctx
2665 * will be 'complete'. See perf_iterate_sb_cpu().
2666 */
2667 smp_store_release(&event->ctx, ctx);
2668
2669 if (!task) {
2670 cpu_function_call(cpu, __perf_install_in_context, event);
2671 return;
2672 }
2673
2674 /*
2675 * Should not happen, we validate the ctx is still alive before calling.
2676 */
2677 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2678 return;
2679
2680 /*
2681 * Installing events is tricky because we cannot rely on ctx->is_active
2682 * to be set in case this is the nr_events 0 -> 1 transition.
2683 *
2684 * Instead we use task_curr(), which tells us if the task is running.
2685 * However, since we use task_curr() outside of rq::lock, we can race
2686 * against the actual state. This means the result can be wrong.
2687 *
2688 * If we get a false positive, we retry, this is harmless.
2689 *
2690 * If we get a false negative, things are complicated. If we are after
2691 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2692 * value must be correct. If we're before, it doesn't matter since
2693 * perf_event_context_sched_in() will program the counter.
2694 *
2695 * However, this hinges on the remote context switch having observed
2696 * our task->perf_event_ctxp[] store, such that it will in fact take
2697 * ctx::lock in perf_event_context_sched_in().
2698 *
2699 * We do this by task_function_call(), if the IPI fails to hit the task
2700 * we know any future context switch of task must see the
2701 * perf_event_ctpx[] store.
2702 */
2703
2704 /*
2705 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2706 * task_cpu() load, such that if the IPI then does not find the task
2707 * running, a future context switch of that task must observe the
2708 * store.
2709 */
2710 smp_mb();
2711again:
2712 if (!task_function_call(task, __perf_install_in_context, event))
2713 return;
2714
2715 raw_spin_lock_irq(&ctx->lock);
2716 task = ctx->task;
2717 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2718 /*
2719 * Cannot happen because we already checked above (which also
2720 * cannot happen), and we hold ctx->mutex, which serializes us
2721 * against perf_event_exit_task_context().
2722 */
2723 raw_spin_unlock_irq(&ctx->lock);
2724 return;
2725 }
2726 /*
2727 * If the task is not running, ctx->lock will avoid it becoming so,
2728 * thus we can safely install the event.
2729 */
2730 if (task_curr(task)) {
2731 raw_spin_unlock_irq(&ctx->lock);
2732 goto again;
2733 }
2734 add_event_to_ctx(event, ctx);
2735 raw_spin_unlock_irq(&ctx->lock);
2736}
2737
2738/*
2739 * Cross CPU call to enable a performance event
2740 */
2741static void __perf_event_enable(struct perf_event *event,
2742 struct perf_cpu_context *cpuctx,
2743 struct perf_event_context *ctx,
2744 void *info)
2745{
2746 struct perf_event *leader = event->group_leader;
2747 struct perf_event_context *task_ctx;
2748
2749 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2750 event->state <= PERF_EVENT_STATE_ERROR)
2751 return;
2752
2753 if (ctx->is_active)
2754 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2755
2756 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2757
2758 if (!ctx->is_active)
2759 return;
2760
2761 if (!event_filter_match(event)) {
2762 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2763 return;
2764 }
2765
2766 /*
2767 * If the event is in a group and isn't the group leader,
2768 * then don't put it on unless the group is on.
2769 */
2770 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2771 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2772 return;
2773 }
2774
2775 task_ctx = cpuctx->task_ctx;
2776 if (ctx->task)
2777 WARN_ON_ONCE(task_ctx != ctx);
2778
2779 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2780}
2781
2782/*
2783 * Enable an event.
2784 *
2785 * If event->ctx is a cloned context, callers must make sure that
2786 * every task struct that event->ctx->task could possibly point to
2787 * remains valid. This condition is satisfied when called through
2788 * perf_event_for_each_child or perf_event_for_each as described
2789 * for perf_event_disable.
2790 */
2791static void _perf_event_enable(struct perf_event *event)
2792{
2793 struct perf_event_context *ctx = event->ctx;
2794
2795 raw_spin_lock_irq(&ctx->lock);
2796 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2797 event->state < PERF_EVENT_STATE_ERROR) {
2798 raw_spin_unlock_irq(&ctx->lock);
2799 return;
2800 }
2801
2802 /*
2803 * If the event is in error state, clear that first.
2804 *
2805 * That way, if we see the event in error state below, we know that it
2806 * has gone back into error state, as distinct from the task having
2807 * been scheduled away before the cross-call arrived.
2808 */
2809 if (event->state == PERF_EVENT_STATE_ERROR)
2810 event->state = PERF_EVENT_STATE_OFF;
2811 raw_spin_unlock_irq(&ctx->lock);
2812
2813 event_function_call(event, __perf_event_enable, NULL);
2814}
2815
2816/*
2817 * See perf_event_disable();
2818 */
2819void perf_event_enable(struct perf_event *event)
2820{
2821 struct perf_event_context *ctx;
2822
2823 ctx = perf_event_ctx_lock(event);
2824 _perf_event_enable(event);
2825 perf_event_ctx_unlock(event, ctx);
2826}
2827EXPORT_SYMBOL_GPL(perf_event_enable);
2828
2829struct stop_event_data {
2830 struct perf_event *event;
2831 unsigned int restart;
2832};
2833
2834static int __perf_event_stop(void *info)
2835{
2836 struct stop_event_data *sd = info;
2837 struct perf_event *event = sd->event;
2838
2839 /* if it's already INACTIVE, do nothing */
2840 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2841 return 0;
2842
2843 /* matches smp_wmb() in event_sched_in() */
2844 smp_rmb();
2845
2846 /*
2847 * There is a window with interrupts enabled before we get here,
2848 * so we need to check again lest we try to stop another CPU's event.
2849 */
2850 if (READ_ONCE(event->oncpu) != smp_processor_id())
2851 return -EAGAIN;
2852
2853 event->pmu->stop(event, PERF_EF_UPDATE);
2854
2855 /*
2856 * May race with the actual stop (through perf_pmu_output_stop()),
2857 * but it is only used for events with AUX ring buffer, and such
2858 * events will refuse to restart because of rb::aux_mmap_count==0,
2859 * see comments in perf_aux_output_begin().
2860 *
2861 * Since this is happening on an event-local CPU, no trace is lost
2862 * while restarting.
2863 */
2864 if (sd->restart)
2865 event->pmu->start(event, 0);
2866
2867 return 0;
2868}
2869
2870static int perf_event_stop(struct perf_event *event, int restart)
2871{
2872 struct stop_event_data sd = {
2873 .event = event,
2874 .restart = restart,
2875 };
2876 int ret = 0;
2877
2878 do {
2879 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2880 return 0;
2881
2882 /* matches smp_wmb() in event_sched_in() */
2883 smp_rmb();
2884
2885 /*
2886 * We only want to restart ACTIVE events, so if the event goes
2887 * inactive here (event->oncpu==-1), there's nothing more to do;
2888 * fall through with ret==-ENXIO.
2889 */
2890 ret = cpu_function_call(READ_ONCE(event->oncpu),
2891 __perf_event_stop, &sd);
2892 } while (ret == -EAGAIN);
2893
2894 return ret;
2895}
2896
2897/*
2898 * In order to contain the amount of racy and tricky in the address filter
2899 * configuration management, it is a two part process:
2900 *
2901 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2902 * we update the addresses of corresponding vmas in
2903 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
2904 * (p2) when an event is scheduled in (pmu::add), it calls
2905 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2906 * if the generation has changed since the previous call.
2907 *
2908 * If (p1) happens while the event is active, we restart it to force (p2).
2909 *
2910 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2911 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2912 * ioctl;
2913 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2914 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2915 * for reading;
2916 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2917 * of exec.
2918 */
2919void perf_event_addr_filters_sync(struct perf_event *event)
2920{
2921 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2922
2923 if (!has_addr_filter(event))
2924 return;
2925
2926 raw_spin_lock(&ifh->lock);
2927 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2928 event->pmu->addr_filters_sync(event);
2929 event->hw.addr_filters_gen = event->addr_filters_gen;
2930 }
2931 raw_spin_unlock(&ifh->lock);
2932}
2933EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2934
2935static int _perf_event_refresh(struct perf_event *event, int refresh)
2936{
2937 /*
2938 * not supported on inherited events
2939 */
2940 if (event->attr.inherit || !is_sampling_event(event))
2941 return -EINVAL;
2942
2943 atomic_add(refresh, &event->event_limit);
2944 _perf_event_enable(event);
2945
2946 return 0;
2947}
2948
2949/*
2950 * See perf_event_disable()
2951 */
2952int perf_event_refresh(struct perf_event *event, int refresh)
2953{
2954 struct perf_event_context *ctx;
2955 int ret;
2956
2957 ctx = perf_event_ctx_lock(event);
2958 ret = _perf_event_refresh(event, refresh);
2959 perf_event_ctx_unlock(event, ctx);
2960
2961 return ret;
2962}
2963EXPORT_SYMBOL_GPL(perf_event_refresh);
2964
2965static int perf_event_modify_breakpoint(struct perf_event *bp,
2966 struct perf_event_attr *attr)
2967{
2968 int err;
2969
2970 _perf_event_disable(bp);
2971
2972 err = modify_user_hw_breakpoint_check(bp, attr, true);
2973
2974 if (!bp->attr.disabled)
2975 _perf_event_enable(bp);
2976
2977 return err;
2978}
2979
2980static int perf_event_modify_attr(struct perf_event *event,
2981 struct perf_event_attr *attr)
2982{
2983 if (event->attr.type != attr->type)
2984 return -EINVAL;
2985
2986 switch (event->attr.type) {
2987 case PERF_TYPE_BREAKPOINT:
2988 return perf_event_modify_breakpoint(event, attr);
2989 default:
2990 /* Place holder for future additions. */
2991 return -EOPNOTSUPP;
2992 }
2993}
2994
2995static void ctx_sched_out(struct perf_event_context *ctx,
2996 struct perf_cpu_context *cpuctx,
2997 enum event_type_t event_type)
2998{
2999 struct perf_event *event, *tmp;
3000 int is_active = ctx->is_active;
3001
3002 lockdep_assert_held(&ctx->lock);
3003
3004 if (likely(!ctx->nr_events)) {
3005 /*
3006 * See __perf_remove_from_context().
3007 */
3008 WARN_ON_ONCE(ctx->is_active);
3009 if (ctx->task)
3010 WARN_ON_ONCE(cpuctx->task_ctx);
3011 return;
3012 }
3013
3014 ctx->is_active &= ~event_type;
3015 if (!(ctx->is_active & EVENT_ALL))
3016 ctx->is_active = 0;
3017
3018 if (ctx->task) {
3019 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3020 if (!ctx->is_active)
3021 cpuctx->task_ctx = NULL;
3022 }
3023
3024 /*
3025 * Always update time if it was set; not only when it changes.
3026 * Otherwise we can 'forget' to update time for any but the last
3027 * context we sched out. For example:
3028 *
3029 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3030 * ctx_sched_out(.event_type = EVENT_PINNED)
3031 *
3032 * would only update time for the pinned events.
3033 */
3034 if (is_active & EVENT_TIME) {
3035 /* update (and stop) ctx time */
3036 update_context_time(ctx);
3037 update_cgrp_time_from_cpuctx(cpuctx);
3038 }
3039
3040 is_active ^= ctx->is_active; /* changed bits */
3041
3042 if (!ctx->nr_active || !(is_active & EVENT_ALL))
3043 return;
3044
3045 /*
3046 * If we had been multiplexing, no rotations are necessary, now no events
3047 * are active.
3048 */
3049 ctx->rotate_necessary = 0;
3050
3051 perf_pmu_disable(ctx->pmu);
3052 if (is_active & EVENT_PINNED) {
3053 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
3054 group_sched_out(event, cpuctx, ctx);
3055 }
3056
3057 if (is_active & EVENT_FLEXIBLE) {
3058 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
3059 group_sched_out(event, cpuctx, ctx);
3060 }
3061 perf_pmu_enable(ctx->pmu);
3062}
3063
3064/*
3065 * Test whether two contexts are equivalent, i.e. whether they have both been
3066 * cloned from the same version of the same context.
3067 *
3068 * Equivalence is measured using a generation number in the context that is
3069 * incremented on each modification to it; see unclone_ctx(), list_add_event()
3070 * and list_del_event().
3071 */
3072static int context_equiv(struct perf_event_context *ctx1,
3073 struct perf_event_context *ctx2)
3074{
3075 lockdep_assert_held(&ctx1->lock);
3076 lockdep_assert_held(&ctx2->lock);
3077
3078 /* Pinning disables the swap optimization */
3079 if (ctx1->pin_count || ctx2->pin_count)
3080 return 0;
3081
3082 /* If ctx1 is the parent of ctx2 */
3083 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3084 return 1;
3085
3086 /* If ctx2 is the parent of ctx1 */
3087 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3088 return 1;
3089
3090 /*
3091 * If ctx1 and ctx2 have the same parent; we flatten the parent
3092 * hierarchy, see perf_event_init_context().
3093 */
3094 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3095 ctx1->parent_gen == ctx2->parent_gen)
3096 return 1;
3097
3098 /* Unmatched */
3099 return 0;
3100}
3101
3102static void __perf_event_sync_stat(struct perf_event *event,
3103 struct perf_event *next_event)
3104{
3105 u64 value;
3106
3107 if (!event->attr.inherit_stat)
3108 return;
3109
3110 /*
3111 * Update the event value, we cannot use perf_event_read()
3112 * because we're in the middle of a context switch and have IRQs
3113 * disabled, which upsets smp_call_function_single(), however
3114 * we know the event must be on the current CPU, therefore we
3115 * don't need to use it.
3116 */
3117 if (event->state == PERF_EVENT_STATE_ACTIVE)
3118 event->pmu->read(event);
3119
3120 perf_event_update_time(event);
3121
3122 /*
3123 * In order to keep per-task stats reliable we need to flip the event
3124 * values when we flip the contexts.
3125 */
3126 value = local64_read(&next_event->count);
3127 value = local64_xchg(&event->count, value);
3128 local64_set(&next_event->count, value);
3129
3130 swap(event->total_time_enabled, next_event->total_time_enabled);
3131 swap(event->total_time_running, next_event->total_time_running);
3132
3133 /*
3134 * Since we swizzled the values, update the user visible data too.
3135 */
3136 perf_event_update_userpage(event);
3137 perf_event_update_userpage(next_event);
3138}
3139
3140static void perf_event_sync_stat(struct perf_event_context *ctx,
3141 struct perf_event_context *next_ctx)
3142{
3143 struct perf_event *event, *next_event;
3144
3145 if (!ctx->nr_stat)
3146 return;
3147
3148 update_context_time(ctx);
3149
3150 event = list_first_entry(&ctx->event_list,
3151 struct perf_event, event_entry);
3152
3153 next_event = list_first_entry(&next_ctx->event_list,
3154 struct perf_event, event_entry);
3155
3156 while (&event->event_entry != &ctx->event_list &&
3157 &next_event->event_entry != &next_ctx->event_list) {
3158
3159 __perf_event_sync_stat(event, next_event);
3160
3161 event = list_next_entry(event, event_entry);
3162 next_event = list_next_entry(next_event, event_entry);
3163 }
3164}
3165
3166static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3167 struct task_struct *next)
3168{
3169 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3170 struct perf_event_context *next_ctx;
3171 struct perf_event_context *parent, *next_parent;
3172 struct perf_cpu_context *cpuctx;
3173 int do_switch = 1;
3174
3175 if (likely(!ctx))
3176 return;
3177
3178 cpuctx = __get_cpu_context(ctx);
3179 if (!cpuctx->task_ctx)
3180 return;
3181
3182 rcu_read_lock();
3183 next_ctx = next->perf_event_ctxp[ctxn];
3184 if (!next_ctx)
3185 goto unlock;
3186
3187 parent = rcu_dereference(ctx->parent_ctx);
3188 next_parent = rcu_dereference(next_ctx->parent_ctx);
3189
3190 /* If neither context have a parent context; they cannot be clones. */
3191 if (!parent && !next_parent)
3192 goto unlock;
3193
3194 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3195 /*
3196 * Looks like the two contexts are clones, so we might be
3197 * able to optimize the context switch. We lock both
3198 * contexts and check that they are clones under the
3199 * lock (including re-checking that neither has been
3200 * uncloned in the meantime). It doesn't matter which
3201 * order we take the locks because no other cpu could
3202 * be trying to lock both of these tasks.
3203 */
3204 raw_spin_lock(&ctx->lock);
3205 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3206 if (context_equiv(ctx, next_ctx)) {
3207 WRITE_ONCE(ctx->task, next);
3208 WRITE_ONCE(next_ctx->task, task);
3209
3210 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3211
3212 /*
3213 * RCU_INIT_POINTER here is safe because we've not
3214 * modified the ctx and the above modification of
3215 * ctx->task and ctx->task_ctx_data are immaterial
3216 * since those values are always verified under
3217 * ctx->lock which we're now holding.
3218 */
3219 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3220 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3221
3222 do_switch = 0;
3223
3224 perf_event_sync_stat(ctx, next_ctx);
3225 }
3226 raw_spin_unlock(&next_ctx->lock);
3227 raw_spin_unlock(&ctx->lock);
3228 }
3229unlock:
3230 rcu_read_unlock();
3231
3232 if (do_switch) {
3233 raw_spin_lock(&ctx->lock);
3234 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3235 raw_spin_unlock(&ctx->lock);
3236 }
3237}
3238
3239static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3240
3241void perf_sched_cb_dec(struct pmu *pmu)
3242{
3243 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3244
3245 this_cpu_dec(perf_sched_cb_usages);
3246
3247 if (!--cpuctx->sched_cb_usage)
3248 list_del(&cpuctx->sched_cb_entry);
3249}
3250
3251
3252void perf_sched_cb_inc(struct pmu *pmu)
3253{
3254 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3255
3256 if (!cpuctx->sched_cb_usage++)
3257 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3258
3259 this_cpu_inc(perf_sched_cb_usages);
3260}
3261
3262/*
3263 * This function provides the context switch callback to the lower code
3264 * layer. It is invoked ONLY when the context switch callback is enabled.
3265 *
3266 * This callback is relevant even to per-cpu events; for example multi event
3267 * PEBS requires this to provide PID/TID information. This requires we flush
3268 * all queued PEBS records before we context switch to a new task.
3269 */
3270static void perf_pmu_sched_task(struct task_struct *prev,
3271 struct task_struct *next,
3272 bool sched_in)
3273{
3274 struct perf_cpu_context *cpuctx;
3275 struct pmu *pmu;
3276
3277 if (prev == next)
3278 return;
3279
3280 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3281 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3282
3283 if (WARN_ON_ONCE(!pmu->sched_task))
3284 continue;
3285
3286 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3287 perf_pmu_disable(pmu);
3288
3289 pmu->sched_task(cpuctx->task_ctx, sched_in);
3290
3291 perf_pmu_enable(pmu);
3292 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3293 }
3294}
3295
3296static void perf_event_switch(struct task_struct *task,
3297 struct task_struct *next_prev, bool sched_in);
3298
3299#define for_each_task_context_nr(ctxn) \
3300 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3301
3302/*
3303 * Called from scheduler to remove the events of the current task,
3304 * with interrupts disabled.
3305 *
3306 * We stop each event and update the event value in event->count.
3307 *
3308 * This does not protect us against NMI, but disable()
3309 * sets the disabled bit in the control field of event _before_
3310 * accessing the event control register. If a NMI hits, then it will
3311 * not restart the event.
3312 */
3313void __perf_event_task_sched_out(struct task_struct *task,
3314 struct task_struct *next)
3315{
3316 int ctxn;
3317
3318 if (__this_cpu_read(perf_sched_cb_usages))
3319 perf_pmu_sched_task(task, next, false);
3320
3321 if (atomic_read(&nr_switch_events))
3322 perf_event_switch(task, next, false);
3323
3324 for_each_task_context_nr(ctxn)
3325 perf_event_context_sched_out(task, ctxn, next);
3326
3327 /*
3328 * if cgroup events exist on this CPU, then we need
3329 * to check if we have to switch out PMU state.
3330 * cgroup event are system-wide mode only
3331 */
3332 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3333 perf_cgroup_sched_out(task, next);
3334}
3335
3336/*
3337 * Called with IRQs disabled
3338 */
3339static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3340 enum event_type_t event_type)
3341{
3342 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3343}
3344
3345static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
3346 int (*func)(struct perf_event *, void *), void *data)
3347{
3348 struct perf_event **evt, *evt1, *evt2;
3349 int ret;
3350
3351 evt1 = perf_event_groups_first(groups, -1);
3352 evt2 = perf_event_groups_first(groups, cpu);
3353
3354 while (evt1 || evt2) {
3355 if (evt1 && evt2) {
3356 if (evt1->group_index < evt2->group_index)
3357 evt = &evt1;
3358 else
3359 evt = &evt2;
3360 } else if (evt1) {
3361 evt = &evt1;
3362 } else {
3363 evt = &evt2;
3364 }
3365
3366 ret = func(*evt, data);
3367 if (ret)
3368 return ret;
3369
3370 *evt = perf_event_groups_next(*evt);
3371 }
3372
3373 return 0;
3374}
3375
3376struct sched_in_data {
3377 struct perf_event_context *ctx;
3378 struct perf_cpu_context *cpuctx;
3379 int can_add_hw;
3380};
3381
3382static int pinned_sched_in(struct perf_event *event, void *data)
3383{
3384 struct sched_in_data *sid = data;
3385
3386 if (event->state <= PERF_EVENT_STATE_OFF)
3387 return 0;
3388
3389 if (!event_filter_match(event))
3390 return 0;
3391
3392 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3393 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3394 list_add_tail(&event->active_list, &sid->ctx->pinned_active);
3395 }
3396
3397 /*
3398 * If this pinned group hasn't been scheduled,
3399 * put it in error state.
3400 */
3401 if (event->state == PERF_EVENT_STATE_INACTIVE)
3402 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3403
3404 return 0;
3405}
3406
3407static int flexible_sched_in(struct perf_event *event, void *data)
3408{
3409 struct sched_in_data *sid = data;
3410
3411 if (event->state <= PERF_EVENT_STATE_OFF)
3412 return 0;
3413
3414 if (!event_filter_match(event))
3415 return 0;
3416
3417 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3418 int ret = group_sched_in(event, sid->cpuctx, sid->ctx);
3419 if (ret) {
3420 sid->can_add_hw = 0;
3421 sid->ctx->rotate_necessary = 1;
3422 return 0;
3423 }
3424 list_add_tail(&event->active_list, &sid->ctx->flexible_active);
3425 }
3426
3427 return 0;
3428}
3429
3430static void
3431ctx_pinned_sched_in(struct perf_event_context *ctx,
3432 struct perf_cpu_context *cpuctx)
3433{
3434 struct sched_in_data sid = {
3435 .ctx = ctx,
3436 .cpuctx = cpuctx,
3437 .can_add_hw = 1,
3438 };
3439
3440 visit_groups_merge(&ctx->pinned_groups,
3441 smp_processor_id(),
3442 pinned_sched_in, &sid);
3443}
3444
3445static void
3446ctx_flexible_sched_in(struct perf_event_context *ctx,
3447 struct perf_cpu_context *cpuctx)
3448{
3449 struct sched_in_data sid = {
3450 .ctx = ctx,
3451 .cpuctx = cpuctx,
3452 .can_add_hw = 1,
3453 };
3454
3455 visit_groups_merge(&ctx->flexible_groups,
3456 smp_processor_id(),
3457 flexible_sched_in, &sid);
3458}
3459
3460static void
3461ctx_sched_in(struct perf_event_context *ctx,
3462 struct perf_cpu_context *cpuctx,
3463 enum event_type_t event_type,
3464 struct task_struct *task)
3465{
3466 int is_active = ctx->is_active;
3467 u64 now;
3468
3469 lockdep_assert_held(&ctx->lock);
3470
3471 if (likely(!ctx->nr_events))
3472 return;
3473
3474 ctx->is_active |= (event_type | EVENT_TIME);
3475 if (ctx->task) {
3476 if (!is_active)
3477 cpuctx->task_ctx = ctx;
3478 else
3479 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3480 }
3481
3482 is_active ^= ctx->is_active; /* changed bits */
3483
3484 if (is_active & EVENT_TIME) {
3485 /* start ctx time */
3486 now = perf_clock();
3487 ctx->timestamp = now;
3488 perf_cgroup_set_timestamp(task, ctx);
3489 }
3490
3491 /*
3492 * First go through the list and put on any pinned groups
3493 * in order to give them the best chance of going on.
3494 */
3495 if (is_active & EVENT_PINNED)
3496 ctx_pinned_sched_in(ctx, cpuctx);
3497
3498 /* Then walk through the lower prio flexible groups */
3499 if (is_active & EVENT_FLEXIBLE)
3500 ctx_flexible_sched_in(ctx, cpuctx);
3501}
3502
3503static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3504 enum event_type_t event_type,
3505 struct task_struct *task)
3506{
3507 struct perf_event_context *ctx = &cpuctx->ctx;
3508
3509 ctx_sched_in(ctx, cpuctx, event_type, task);
3510}
3511
3512static void perf_event_context_sched_in(struct perf_event_context *ctx,
3513 struct task_struct *task)
3514{
3515 struct perf_cpu_context *cpuctx;
3516
3517 cpuctx = __get_cpu_context(ctx);
3518 if (cpuctx->task_ctx == ctx)
3519 return;
3520
3521 perf_ctx_lock(cpuctx, ctx);
3522 /*
3523 * We must check ctx->nr_events while holding ctx->lock, such
3524 * that we serialize against perf_install_in_context().
3525 */
3526 if (!ctx->nr_events)
3527 goto unlock;
3528
3529 perf_pmu_disable(ctx->pmu);
3530 /*
3531 * We want to keep the following priority order:
3532 * cpu pinned (that don't need to move), task pinned,
3533 * cpu flexible, task flexible.
3534 *
3535 * However, if task's ctx is not carrying any pinned
3536 * events, no need to flip the cpuctx's events around.
3537 */
3538 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3539 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3540 perf_event_sched_in(cpuctx, ctx, task);
3541 perf_pmu_enable(ctx->pmu);
3542
3543unlock:
3544 perf_ctx_unlock(cpuctx, ctx);
3545}
3546
3547/*
3548 * Called from scheduler to add the events of the current task
3549 * with interrupts disabled.
3550 *
3551 * We restore the event value and then enable it.
3552 *
3553 * This does not protect us against NMI, but enable()
3554 * sets the enabled bit in the control field of event _before_
3555 * accessing the event control register. If a NMI hits, then it will
3556 * keep the event running.
3557 */
3558void __perf_event_task_sched_in(struct task_struct *prev,
3559 struct task_struct *task)
3560{
3561 struct perf_event_context *ctx;
3562 int ctxn;
3563
3564 /*
3565 * If cgroup events exist on this CPU, then we need to check if we have
3566 * to switch in PMU state; cgroup event are system-wide mode only.
3567 *
3568 * Since cgroup events are CPU events, we must schedule these in before
3569 * we schedule in the task events.
3570 */
3571 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3572 perf_cgroup_sched_in(prev, task);
3573
3574 for_each_task_context_nr(ctxn) {
3575 ctx = task->perf_event_ctxp[ctxn];
3576 if (likely(!ctx))
3577 continue;
3578
3579 perf_event_context_sched_in(ctx, task);
3580 }
3581
3582 if (atomic_read(&nr_switch_events))
3583 perf_event_switch(task, prev, true);
3584
3585 if (__this_cpu_read(perf_sched_cb_usages))
3586 perf_pmu_sched_task(prev, task, true);
3587}
3588
3589static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3590{
3591 u64 frequency = event->attr.sample_freq;
3592 u64 sec = NSEC_PER_SEC;
3593 u64 divisor, dividend;
3594
3595 int count_fls, nsec_fls, frequency_fls, sec_fls;
3596
3597 count_fls = fls64(count);
3598 nsec_fls = fls64(nsec);
3599 frequency_fls = fls64(frequency);
3600 sec_fls = 30;
3601
3602 /*
3603 * We got @count in @nsec, with a target of sample_freq HZ
3604 * the target period becomes:
3605 *
3606 * @count * 10^9
3607 * period = -------------------
3608 * @nsec * sample_freq
3609 *
3610 */
3611
3612 /*
3613 * Reduce accuracy by one bit such that @a and @b converge
3614 * to a similar magnitude.
3615 */
3616#define REDUCE_FLS(a, b) \
3617do { \
3618 if (a##_fls > b##_fls) { \
3619 a >>= 1; \
3620 a##_fls--; \
3621 } else { \
3622 b >>= 1; \
3623 b##_fls--; \
3624 } \
3625} while (0)
3626
3627 /*
3628 * Reduce accuracy until either term fits in a u64, then proceed with
3629 * the other, so that finally we can do a u64/u64 division.
3630 */
3631 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3632 REDUCE_FLS(nsec, frequency);
3633 REDUCE_FLS(sec, count);
3634 }
3635
3636 if (count_fls + sec_fls > 64) {
3637 divisor = nsec * frequency;
3638
3639 while (count_fls + sec_fls > 64) {
3640 REDUCE_FLS(count, sec);
3641 divisor >>= 1;
3642 }
3643
3644 dividend = count * sec;
3645 } else {
3646 dividend = count * sec;
3647
3648 while (nsec_fls + frequency_fls > 64) {
3649 REDUCE_FLS(nsec, frequency);
3650 dividend >>= 1;
3651 }
3652
3653 divisor = nsec * frequency;
3654 }
3655
3656 if (!divisor)
3657 return dividend;
3658
3659 return div64_u64(dividend, divisor);
3660}
3661
3662static DEFINE_PER_CPU(int, perf_throttled_count);
3663static DEFINE_PER_CPU(u64, perf_throttled_seq);
3664
3665static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3666{
3667 struct hw_perf_event *hwc = &event->hw;
3668 s64 period, sample_period;
3669 s64 delta;
3670
3671 period = perf_calculate_period(event, nsec, count);
3672
3673 delta = (s64)(period - hwc->sample_period);
3674 delta = (delta + 7) / 8; /* low pass filter */
3675
3676 sample_period = hwc->sample_period + delta;
3677
3678 if (!sample_period)
3679 sample_period = 1;
3680
3681 hwc->sample_period = sample_period;
3682
3683 if (local64_read(&hwc->period_left) > 8*sample_period) {
3684 if (disable)
3685 event->pmu->stop(event, PERF_EF_UPDATE);
3686
3687 local64_set(&hwc->period_left, 0);
3688
3689 if (disable)
3690 event->pmu->start(event, PERF_EF_RELOAD);
3691 }
3692}
3693
3694/*
3695 * combine freq adjustment with unthrottling to avoid two passes over the
3696 * events. At the same time, make sure, having freq events does not change
3697 * the rate of unthrottling as that would introduce bias.
3698 */
3699static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3700 int needs_unthr)
3701{
3702 struct perf_event *event;
3703 struct hw_perf_event *hwc;
3704 u64 now, period = TICK_NSEC;
3705 s64 delta;
3706
3707 /*
3708 * only need to iterate over all events iff:
3709 * - context have events in frequency mode (needs freq adjust)
3710 * - there are events to unthrottle on this cpu
3711 */
3712 if (!(ctx->nr_freq || needs_unthr))
3713 return;
3714
3715 raw_spin_lock(&ctx->lock);
3716 perf_pmu_disable(ctx->pmu);
3717
3718 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3719 if (event->state != PERF_EVENT_STATE_ACTIVE)
3720 continue;
3721
3722 if (!event_filter_match(event))
3723 continue;
3724
3725 perf_pmu_disable(event->pmu);
3726
3727 hwc = &event->hw;
3728
3729 if (hwc->interrupts == MAX_INTERRUPTS) {
3730 hwc->interrupts = 0;
3731 perf_log_throttle(event, 1);
3732 event->pmu->start(event, 0);
3733 }
3734
3735 if (!event->attr.freq || !event->attr.sample_freq)
3736 goto next;
3737
3738 /*
3739 * stop the event and update event->count
3740 */
3741 event->pmu->stop(event, PERF_EF_UPDATE);
3742
3743 now = local64_read(&event->count);
3744 delta = now - hwc->freq_count_stamp;
3745 hwc->freq_count_stamp = now;
3746
3747 /*
3748 * restart the event
3749 * reload only if value has changed
3750 * we have stopped the event so tell that
3751 * to perf_adjust_period() to avoid stopping it
3752 * twice.
3753 */
3754 if (delta > 0)
3755 perf_adjust_period(event, period, delta, false);
3756
3757 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3758 next:
3759 perf_pmu_enable(event->pmu);
3760 }
3761
3762 perf_pmu_enable(ctx->pmu);
3763 raw_spin_unlock(&ctx->lock);
3764}
3765
3766/*
3767 * Move @event to the tail of the @ctx's elegible events.
3768 */
3769static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
3770{
3771 /*
3772 * Rotate the first entry last of non-pinned groups. Rotation might be
3773 * disabled by the inheritance code.
3774 */
3775 if (ctx->rotate_disable)
3776 return;
3777
3778 perf_event_groups_delete(&ctx->flexible_groups, event);
3779 perf_event_groups_insert(&ctx->flexible_groups, event);
3780}
3781
3782/* pick an event from the flexible_groups to rotate */
3783static inline struct perf_event *
3784ctx_event_to_rotate(struct perf_event_context *ctx)
3785{
3786 struct perf_event *event;
3787
3788 /* pick the first active flexible event */
3789 event = list_first_entry_or_null(&ctx->flexible_active,
3790 struct perf_event, active_list);
3791
3792 /* if no active flexible event, pick the first event */
3793 if (!event) {
3794 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
3795 typeof(*event), group_node);
3796 }
3797
3798 return event;
3799}
3800
3801static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
3802{
3803 struct perf_event *cpu_event = NULL, *task_event = NULL;
3804 struct perf_event_context *task_ctx = NULL;
3805 int cpu_rotate, task_rotate;
3806
3807 /*
3808 * Since we run this from IRQ context, nobody can install new
3809 * events, thus the event count values are stable.
3810 */
3811
3812 cpu_rotate = cpuctx->ctx.rotate_necessary;
3813 task_ctx = cpuctx->task_ctx;
3814 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
3815
3816 if (!(cpu_rotate || task_rotate))
3817 return false;
3818
3819 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3820 perf_pmu_disable(cpuctx->ctx.pmu);
3821
3822 if (task_rotate)
3823 task_event = ctx_event_to_rotate(task_ctx);
3824 if (cpu_rotate)
3825 cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
3826
3827 /*
3828 * As per the order given at ctx_resched() first 'pop' task flexible
3829 * and then, if needed CPU flexible.
3830 */
3831 if (task_event || (task_ctx && cpu_event))
3832 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
3833 if (cpu_event)
3834 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3835
3836 if (task_event)
3837 rotate_ctx(task_ctx, task_event);
3838 if (cpu_event)
3839 rotate_ctx(&cpuctx->ctx, cpu_event);
3840
3841 perf_event_sched_in(cpuctx, task_ctx, current);
3842
3843 perf_pmu_enable(cpuctx->ctx.pmu);
3844 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3845
3846 return true;
3847}
3848
3849void perf_event_task_tick(void)
3850{
3851 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3852 struct perf_event_context *ctx, *tmp;
3853 int throttled;
3854
3855 lockdep_assert_irqs_disabled();
3856
3857 __this_cpu_inc(perf_throttled_seq);
3858 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3859 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3860
3861 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3862 perf_adjust_freq_unthr_context(ctx, throttled);
3863}
3864
3865static int event_enable_on_exec(struct perf_event *event,
3866 struct perf_event_context *ctx)
3867{
3868 if (!event->attr.enable_on_exec)
3869 return 0;
3870
3871 event->attr.enable_on_exec = 0;
3872 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3873 return 0;
3874
3875 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3876
3877 return 1;
3878}
3879
3880/*
3881 * Enable all of a task's events that have been marked enable-on-exec.
3882 * This expects task == current.
3883 */
3884static void perf_event_enable_on_exec(int ctxn)
3885{
3886 struct perf_event_context *ctx, *clone_ctx = NULL;
3887 enum event_type_t event_type = 0;
3888 struct perf_cpu_context *cpuctx;
3889 struct perf_event *event;
3890 unsigned long flags;
3891 int enabled = 0;
3892
3893 local_irq_save(flags);
3894 ctx = current->perf_event_ctxp[ctxn];
3895 if (!ctx || !ctx->nr_events)
3896 goto out;
3897
3898 cpuctx = __get_cpu_context(ctx);
3899 perf_ctx_lock(cpuctx, ctx);
3900 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3901 list_for_each_entry(event, &ctx->event_list, event_entry) {
3902 enabled |= event_enable_on_exec(event, ctx);
3903 event_type |= get_event_type(event);
3904 }
3905
3906 /*
3907 * Unclone and reschedule this context if we enabled any event.
3908 */
3909 if (enabled) {
3910 clone_ctx = unclone_ctx(ctx);
3911 ctx_resched(cpuctx, ctx, event_type);
3912 } else {
3913 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3914 }
3915 perf_ctx_unlock(cpuctx, ctx);
3916
3917out:
3918 local_irq_restore(flags);
3919
3920 if (clone_ctx)
3921 put_ctx(clone_ctx);
3922}
3923
3924struct perf_read_data {
3925 struct perf_event *event;
3926 bool group;
3927 int ret;
3928};
3929
3930static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3931{
3932 u16 local_pkg, event_pkg;
3933
3934 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3935 int local_cpu = smp_processor_id();
3936
3937 event_pkg = topology_physical_package_id(event_cpu);
3938 local_pkg = topology_physical_package_id(local_cpu);
3939
3940 if (event_pkg == local_pkg)
3941 return local_cpu;
3942 }
3943
3944 return event_cpu;
3945}
3946
3947/*
3948 * Cross CPU call to read the hardware event
3949 */
3950static void __perf_event_read(void *info)
3951{
3952 struct perf_read_data *data = info;
3953 struct perf_event *sub, *event = data->event;
3954 struct perf_event_context *ctx = event->ctx;
3955 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3956 struct pmu *pmu = event->pmu;
3957
3958 /*
3959 * If this is a task context, we need to check whether it is
3960 * the current task context of this cpu. If not it has been
3961 * scheduled out before the smp call arrived. In that case
3962 * event->count would have been updated to a recent sample
3963 * when the event was scheduled out.
3964 */
3965 if (ctx->task && cpuctx->task_ctx != ctx)
3966 return;
3967
3968 raw_spin_lock(&ctx->lock);
3969 if (ctx->is_active & EVENT_TIME) {
3970 update_context_time(ctx);
3971 update_cgrp_time_from_event(event);
3972 }
3973
3974 perf_event_update_time(event);
3975 if (data->group)
3976 perf_event_update_sibling_time(event);
3977
3978 if (event->state != PERF_EVENT_STATE_ACTIVE)
3979 goto unlock;
3980
3981 if (!data->group) {
3982 pmu->read(event);
3983 data->ret = 0;
3984 goto unlock;
3985 }
3986
3987 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3988
3989 pmu->read(event);
3990
3991 for_each_sibling_event(sub, event) {
3992 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3993 /*
3994 * Use sibling's PMU rather than @event's since
3995 * sibling could be on different (eg: software) PMU.
3996 */
3997 sub->pmu->read(sub);
3998 }
3999 }
4000
4001 data->ret = pmu->commit_txn(pmu);
4002
4003unlock:
4004 raw_spin_unlock(&ctx->lock);
4005}
4006
4007static inline u64 perf_event_count(struct perf_event *event)
4008{
4009 return local64_read(&event->count) + atomic64_read(&event->child_count);
4010}
4011
4012/*
4013 * NMI-safe method to read a local event, that is an event that
4014 * is:
4015 * - either for the current task, or for this CPU
4016 * - does not have inherit set, for inherited task events
4017 * will not be local and we cannot read them atomically
4018 * - must not have a pmu::count method
4019 */
4020int perf_event_read_local(struct perf_event *event, u64 *value,
4021 u64 *enabled, u64 *running)
4022{
4023 unsigned long flags;
4024 int ret = 0;
4025
4026 /*
4027 * Disabling interrupts avoids all counter scheduling (context
4028 * switches, timer based rotation and IPIs).
4029 */
4030 local_irq_save(flags);
4031
4032 /*
4033 * It must not be an event with inherit set, we cannot read
4034 * all child counters from atomic context.
4035 */
4036 if (event->attr.inherit) {
4037 ret = -EOPNOTSUPP;
4038 goto out;
4039 }
4040
4041 /* If this is a per-task event, it must be for current */
4042 if ((event->attach_state & PERF_ATTACH_TASK) &&
4043 event->hw.target != current) {
4044 ret = -EINVAL;
4045 goto out;
4046 }
4047
4048 /* If this is a per-CPU event, it must be for this CPU */
4049 if (!(event->attach_state & PERF_ATTACH_TASK) &&
4050 event->cpu != smp_processor_id()) {
4051 ret = -EINVAL;
4052 goto out;
4053 }
4054
4055 /* If this is a pinned event it must be running on this CPU */
4056 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4057 ret = -EBUSY;
4058 goto out;
4059 }
4060
4061 /*
4062 * If the event is currently on this CPU, its either a per-task event,
4063 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4064 * oncpu == -1).
4065 */
4066 if (event->oncpu == smp_processor_id())
4067 event->pmu->read(event);
4068
4069 *value = local64_read(&event->count);
4070 if (enabled || running) {
4071 u64 now = event->shadow_ctx_time + perf_clock();
4072 u64 __enabled, __running;
4073
4074 __perf_update_times(event, now, &__enabled, &__running);
4075 if (enabled)
4076 *enabled = __enabled;
4077 if (running)
4078 *running = __running;
4079 }
4080out:
4081 local_irq_restore(flags);
4082
4083 return ret;
4084}
4085
4086static int perf_event_read(struct perf_event *event, bool group)
4087{
4088 enum perf_event_state state = READ_ONCE(event->state);
4089 int event_cpu, ret = 0;
4090
4091 /*
4092 * If event is enabled and currently active on a CPU, update the
4093 * value in the event structure:
4094 */
4095again:
4096 if (state == PERF_EVENT_STATE_ACTIVE) {
4097 struct perf_read_data data;
4098
4099 /*
4100 * Orders the ->state and ->oncpu loads such that if we see
4101 * ACTIVE we must also see the right ->oncpu.
4102 *
4103 * Matches the smp_wmb() from event_sched_in().
4104 */
4105 smp_rmb();
4106
4107 event_cpu = READ_ONCE(event->oncpu);
4108 if ((unsigned)event_cpu >= nr_cpu_ids)
4109 return 0;
4110
4111 data = (struct perf_read_data){
4112 .event = event,
4113 .group = group,
4114 .ret = 0,
4115 };
4116
4117 preempt_disable();
4118 event_cpu = __perf_event_read_cpu(event, event_cpu);
4119
4120 /*
4121 * Purposely ignore the smp_call_function_single() return
4122 * value.
4123 *
4124 * If event_cpu isn't a valid CPU it means the event got
4125 * scheduled out and that will have updated the event count.
4126 *
4127 * Therefore, either way, we'll have an up-to-date event count
4128 * after this.
4129 */
4130 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4131 preempt_enable();
4132 ret = data.ret;
4133
4134 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4135 struct perf_event_context *ctx = event->ctx;
4136 unsigned long flags;
4137
4138 raw_spin_lock_irqsave(&ctx->lock, flags);
4139 state = event->state;
4140 if (state != PERF_EVENT_STATE_INACTIVE) {
4141 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4142 goto again;
4143 }
4144
4145 /*
4146 * May read while context is not active (e.g., thread is
4147 * blocked), in that case we cannot update context time
4148 */
4149 if (ctx->is_active & EVENT_TIME) {
4150 update_context_time(ctx);
4151 update_cgrp_time_from_event(event);
4152 }
4153
4154 perf_event_update_time(event);
4155 if (group)
4156 perf_event_update_sibling_time(event);
4157 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4158 }
4159
4160 return ret;
4161}
4162
4163/*
4164 * Initialize the perf_event context in a task_struct:
4165 */
4166static void __perf_event_init_context(struct perf_event_context *ctx)
4167{
4168 raw_spin_lock_init(&ctx->lock);
4169 mutex_init(&ctx->mutex);
4170 INIT_LIST_HEAD(&ctx->active_ctx_list);
4171 perf_event_groups_init(&ctx->pinned_groups);
4172 perf_event_groups_init(&ctx->flexible_groups);
4173 INIT_LIST_HEAD(&ctx->event_list);
4174 INIT_LIST_HEAD(&ctx->pinned_active);
4175 INIT_LIST_HEAD(&ctx->flexible_active);
4176 refcount_set(&ctx->refcount, 1);
4177}
4178
4179static struct perf_event_context *
4180alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4181{
4182 struct perf_event_context *ctx;
4183
4184 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4185 if (!ctx)
4186 return NULL;
4187
4188 __perf_event_init_context(ctx);
4189 if (task)
4190 ctx->task = get_task_struct(task);
4191 ctx->pmu = pmu;
4192
4193 return ctx;
4194}
4195
4196static struct task_struct *
4197find_lively_task_by_vpid(pid_t vpid)
4198{
4199 struct task_struct *task;
4200
4201 rcu_read_lock();
4202 if (!vpid)
4203 task = current;
4204 else
4205 task = find_task_by_vpid(vpid);
4206 if (task)
4207 get_task_struct(task);
4208 rcu_read_unlock();
4209
4210 if (!task)
4211 return ERR_PTR(-ESRCH);
4212
4213 return task;
4214}
4215
4216/*
4217 * Returns a matching context with refcount and pincount.
4218 */
4219static struct perf_event_context *
4220find_get_context(struct pmu *pmu, struct task_struct *task,
4221 struct perf_event *event)
4222{
4223 struct perf_event_context *ctx, *clone_ctx = NULL;
4224 struct perf_cpu_context *cpuctx;
4225 void *task_ctx_data = NULL;
4226 unsigned long flags;
4227 int ctxn, err;
4228 int cpu = event->cpu;
4229
4230 if (!task) {
4231 /* Must be root to operate on a CPU event: */
4232 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
4233 return ERR_PTR(-EACCES);
4234
4235 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4236 ctx = &cpuctx->ctx;
4237 get_ctx(ctx);
4238 ++ctx->pin_count;
4239
4240 return ctx;
4241 }
4242
4243 err = -EINVAL;
4244 ctxn = pmu->task_ctx_nr;
4245 if (ctxn < 0)
4246 goto errout;
4247
4248 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4249 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4250 if (!task_ctx_data) {
4251 err = -ENOMEM;
4252 goto errout;
4253 }
4254 }
4255
4256retry:
4257 ctx = perf_lock_task_context(task, ctxn, &flags);
4258 if (ctx) {
4259 clone_ctx = unclone_ctx(ctx);
4260 ++ctx->pin_count;
4261
4262 if (task_ctx_data && !ctx->task_ctx_data) {
4263 ctx->task_ctx_data = task_ctx_data;
4264 task_ctx_data = NULL;
4265 }
4266 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4267
4268 if (clone_ctx)
4269 put_ctx(clone_ctx);
4270 } else {
4271 ctx = alloc_perf_context(pmu, task);
4272 err = -ENOMEM;
4273 if (!ctx)
4274 goto errout;
4275
4276 if (task_ctx_data) {
4277 ctx->task_ctx_data = task_ctx_data;
4278 task_ctx_data = NULL;
4279 }
4280
4281 err = 0;
4282 mutex_lock(&task->perf_event_mutex);
4283 /*
4284 * If it has already passed perf_event_exit_task().
4285 * we must see PF_EXITING, it takes this mutex too.
4286 */
4287 if (task->flags & PF_EXITING)
4288 err = -ESRCH;
4289 else if (task->perf_event_ctxp[ctxn])
4290 err = -EAGAIN;
4291 else {
4292 get_ctx(ctx);
4293 ++ctx->pin_count;
4294 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4295 }
4296 mutex_unlock(&task->perf_event_mutex);
4297
4298 if (unlikely(err)) {
4299 put_ctx(ctx);
4300
4301 if (err == -EAGAIN)
4302 goto retry;
4303 goto errout;
4304 }
4305 }
4306
4307 kfree(task_ctx_data);
4308 return ctx;
4309
4310errout:
4311 kfree(task_ctx_data);
4312 return ERR_PTR(err);
4313}
4314
4315static void perf_event_free_filter(struct perf_event *event);
4316static void perf_event_free_bpf_prog(struct perf_event *event);
4317
4318static void free_event_rcu(struct rcu_head *head)
4319{
4320 struct perf_event *event;
4321
4322 event = container_of(head, struct perf_event, rcu_head);
4323 if (event->ns)
4324 put_pid_ns(event->ns);
4325 perf_event_free_filter(event);
4326 kfree(event);
4327}
4328
4329static void ring_buffer_attach(struct perf_event *event,
4330 struct ring_buffer *rb);
4331
4332static void detach_sb_event(struct perf_event *event)
4333{
4334 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4335
4336 raw_spin_lock(&pel->lock);
4337 list_del_rcu(&event->sb_list);
4338 raw_spin_unlock(&pel->lock);
4339}
4340
4341static bool is_sb_event(struct perf_event *event)
4342{
4343 struct perf_event_attr *attr = &event->attr;
4344
4345 if (event->parent)
4346 return false;
4347
4348 if (event->attach_state & PERF_ATTACH_TASK)
4349 return false;
4350
4351 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4352 attr->comm || attr->comm_exec ||
4353 attr->task || attr->ksymbol ||
4354 attr->context_switch ||
4355 attr->bpf_event)
4356 return true;
4357 return false;
4358}
4359
4360static void unaccount_pmu_sb_event(struct perf_event *event)
4361{
4362 if (is_sb_event(event))
4363 detach_sb_event(event);
4364}
4365
4366static void unaccount_event_cpu(struct perf_event *event, int cpu)
4367{
4368 if (event->parent)
4369 return;
4370
4371 if (is_cgroup_event(event))
4372 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4373}
4374
4375#ifdef CONFIG_NO_HZ_FULL
4376static DEFINE_SPINLOCK(nr_freq_lock);
4377#endif
4378
4379static void unaccount_freq_event_nohz(void)
4380{
4381#ifdef CONFIG_NO_HZ_FULL
4382 spin_lock(&nr_freq_lock);
4383 if (atomic_dec_and_test(&nr_freq_events))
4384 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4385 spin_unlock(&nr_freq_lock);
4386#endif
4387}
4388
4389static void unaccount_freq_event(void)
4390{
4391 if (tick_nohz_full_enabled())
4392 unaccount_freq_event_nohz();
4393 else
4394 atomic_dec(&nr_freq_events);
4395}
4396
4397static void unaccount_event(struct perf_event *event)
4398{
4399 bool dec = false;
4400
4401 if (event->parent)
4402 return;
4403
4404 if (event->attach_state & PERF_ATTACH_TASK)
4405 dec = true;
4406 if (event->attr.mmap || event->attr.mmap_data)
4407 atomic_dec(&nr_mmap_events);
4408 if (event->attr.comm)
4409 atomic_dec(&nr_comm_events);
4410 if (event->attr.namespaces)
4411 atomic_dec(&nr_namespaces_events);
4412 if (event->attr.task)
4413 atomic_dec(&nr_task_events);
4414 if (event->attr.freq)
4415 unaccount_freq_event();
4416 if (event->attr.context_switch) {
4417 dec = true;
4418 atomic_dec(&nr_switch_events);
4419 }
4420 if (is_cgroup_event(event))
4421 dec = true;
4422 if (has_branch_stack(event))
4423 dec = true;
4424 if (event->attr.ksymbol)
4425 atomic_dec(&nr_ksymbol_events);
4426 if (event->attr.bpf_event)
4427 atomic_dec(&nr_bpf_events);
4428
4429 if (dec) {
4430 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4431 schedule_delayed_work(&perf_sched_work, HZ);
4432 }
4433
4434 unaccount_event_cpu(event, event->cpu);
4435
4436 unaccount_pmu_sb_event(event);
4437}
4438
4439static void perf_sched_delayed(struct work_struct *work)
4440{
4441 mutex_lock(&perf_sched_mutex);
4442 if (atomic_dec_and_test(&perf_sched_count))
4443 static_branch_disable(&perf_sched_events);
4444 mutex_unlock(&perf_sched_mutex);
4445}
4446
4447/*
4448 * The following implement mutual exclusion of events on "exclusive" pmus
4449 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4450 * at a time, so we disallow creating events that might conflict, namely:
4451 *
4452 * 1) cpu-wide events in the presence of per-task events,
4453 * 2) per-task events in the presence of cpu-wide events,
4454 * 3) two matching events on the same context.
4455 *
4456 * The former two cases are handled in the allocation path (perf_event_alloc(),
4457 * _free_event()), the latter -- before the first perf_install_in_context().
4458 */
4459static int exclusive_event_init(struct perf_event *event)
4460{
4461 struct pmu *pmu = event->pmu;
4462
4463 if (!is_exclusive_pmu(pmu))
4464 return 0;
4465
4466 /*
4467 * Prevent co-existence of per-task and cpu-wide events on the
4468 * same exclusive pmu.
4469 *
4470 * Negative pmu::exclusive_cnt means there are cpu-wide
4471 * events on this "exclusive" pmu, positive means there are
4472 * per-task events.
4473 *
4474 * Since this is called in perf_event_alloc() path, event::ctx
4475 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4476 * to mean "per-task event", because unlike other attach states it
4477 * never gets cleared.
4478 */
4479 if (event->attach_state & PERF_ATTACH_TASK) {
4480 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4481 return -EBUSY;
4482 } else {
4483 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4484 return -EBUSY;
4485 }
4486
4487 return 0;
4488}
4489
4490static void exclusive_event_destroy(struct perf_event *event)
4491{
4492 struct pmu *pmu = event->pmu;
4493
4494 if (!is_exclusive_pmu(pmu))
4495 return;
4496
4497 /* see comment in exclusive_event_init() */
4498 if (event->attach_state & PERF_ATTACH_TASK)
4499 atomic_dec(&pmu->exclusive_cnt);
4500 else
4501 atomic_inc(&pmu->exclusive_cnt);
4502}
4503
4504static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4505{
4506 if ((e1->pmu == e2->pmu) &&
4507 (e1->cpu == e2->cpu ||
4508 e1->cpu == -1 ||
4509 e2->cpu == -1))
4510 return true;
4511 return false;
4512}
4513
4514static bool exclusive_event_installable(struct perf_event *event,
4515 struct perf_event_context *ctx)
4516{
4517 struct perf_event *iter_event;
4518 struct pmu *pmu = event->pmu;
4519
4520 lockdep_assert_held(&ctx->mutex);
4521
4522 if (!is_exclusive_pmu(pmu))
4523 return true;
4524
4525 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4526 if (exclusive_event_match(iter_event, event))
4527 return false;
4528 }
4529
4530 return true;
4531}
4532
4533static void perf_addr_filters_splice(struct perf_event *event,
4534 struct list_head *head);
4535
4536static void _free_event(struct perf_event *event)
4537{
4538 irq_work_sync(&event->pending);
4539
4540 unaccount_event(event);
4541
4542 if (event->rb) {
4543 /*
4544 * Can happen when we close an event with re-directed output.
4545 *
4546 * Since we have a 0 refcount, perf_mmap_close() will skip
4547 * over us; possibly making our ring_buffer_put() the last.
4548 */
4549 mutex_lock(&event->mmap_mutex);
4550 ring_buffer_attach(event, NULL);
4551 mutex_unlock(&event->mmap_mutex);
4552 }
4553
4554 if (is_cgroup_event(event))
4555 perf_detach_cgroup(event);
4556
4557 if (!event->parent) {
4558 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4559 put_callchain_buffers();
4560 }
4561
4562 perf_event_free_bpf_prog(event);
4563 perf_addr_filters_splice(event, NULL);
4564 kfree(event->addr_filter_ranges);
4565
4566 if (event->destroy)
4567 event->destroy(event);
4568
4569 /*
4570 * Must be after ->destroy(), due to uprobe_perf_close() using
4571 * hw.target.
4572 */
4573 if (event->hw.target)
4574 put_task_struct(event->hw.target);
4575
4576 /*
4577 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4578 * all task references must be cleaned up.
4579 */
4580 if (event->ctx)
4581 put_ctx(event->ctx);
4582
4583 exclusive_event_destroy(event);
4584 module_put(event->pmu->module);
4585
4586 call_rcu(&event->rcu_head, free_event_rcu);
4587}
4588
4589/*
4590 * Used to free events which have a known refcount of 1, such as in error paths
4591 * where the event isn't exposed yet and inherited events.
4592 */
4593static void free_event(struct perf_event *event)
4594{
4595 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4596 "unexpected event refcount: %ld; ptr=%p\n",
4597 atomic_long_read(&event->refcount), event)) {
4598 /* leak to avoid use-after-free */
4599 return;
4600 }
4601
4602 _free_event(event);
4603}
4604
4605/*
4606 * Remove user event from the owner task.
4607 */
4608static void perf_remove_from_owner(struct perf_event *event)
4609{
4610 struct task_struct *owner;
4611
4612 rcu_read_lock();
4613 /*
4614 * Matches the smp_store_release() in perf_event_exit_task(). If we
4615 * observe !owner it means the list deletion is complete and we can
4616 * indeed free this event, otherwise we need to serialize on
4617 * owner->perf_event_mutex.
4618 */
4619 owner = READ_ONCE(event->owner);
4620 if (owner) {
4621 /*
4622 * Since delayed_put_task_struct() also drops the last
4623 * task reference we can safely take a new reference
4624 * while holding the rcu_read_lock().
4625 */
4626 get_task_struct(owner);
4627 }
4628 rcu_read_unlock();
4629
4630 if (owner) {
4631 /*
4632 * If we're here through perf_event_exit_task() we're already
4633 * holding ctx->mutex which would be an inversion wrt. the
4634 * normal lock order.
4635 *
4636 * However we can safely take this lock because its the child
4637 * ctx->mutex.
4638 */
4639 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4640
4641 /*
4642 * We have to re-check the event->owner field, if it is cleared
4643 * we raced with perf_event_exit_task(), acquiring the mutex
4644 * ensured they're done, and we can proceed with freeing the
4645 * event.
4646 */
4647 if (event->owner) {
4648 list_del_init(&event->owner_entry);
4649 smp_store_release(&event->owner, NULL);
4650 }
4651 mutex_unlock(&owner->perf_event_mutex);
4652 put_task_struct(owner);
4653 }
4654}
4655
4656static void put_event(struct perf_event *event)
4657{
4658 if (!atomic_long_dec_and_test(&event->refcount))
4659 return;
4660
4661 _free_event(event);
4662}
4663
4664/*
4665 * Kill an event dead; while event:refcount will preserve the event
4666 * object, it will not preserve its functionality. Once the last 'user'
4667 * gives up the object, we'll destroy the thing.
4668 */
4669int perf_event_release_kernel(struct perf_event *event)
4670{
4671 struct perf_event_context *ctx = event->ctx;
4672 struct perf_event *child, *tmp;
4673 LIST_HEAD(free_list);
4674
4675 /*
4676 * If we got here through err_file: fput(event_file); we will not have
4677 * attached to a context yet.
4678 */
4679 if (!ctx) {
4680 WARN_ON_ONCE(event->attach_state &
4681 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4682 goto no_ctx;
4683 }
4684
4685 if (!is_kernel_event(event))
4686 perf_remove_from_owner(event);
4687
4688 ctx = perf_event_ctx_lock(event);
4689 WARN_ON_ONCE(ctx->parent_ctx);
4690 perf_remove_from_context(event, DETACH_GROUP);
4691
4692 raw_spin_lock_irq(&ctx->lock);
4693 /*
4694 * Mark this event as STATE_DEAD, there is no external reference to it
4695 * anymore.
4696 *
4697 * Anybody acquiring event->child_mutex after the below loop _must_
4698 * also see this, most importantly inherit_event() which will avoid
4699 * placing more children on the list.
4700 *
4701 * Thus this guarantees that we will in fact observe and kill _ALL_
4702 * child events.
4703 */
4704 event->state = PERF_EVENT_STATE_DEAD;
4705 raw_spin_unlock_irq(&ctx->lock);
4706
4707 perf_event_ctx_unlock(event, ctx);
4708
4709again:
4710 mutex_lock(&event->child_mutex);
4711 list_for_each_entry(child, &event->child_list, child_list) {
4712
4713 /*
4714 * Cannot change, child events are not migrated, see the
4715 * comment with perf_event_ctx_lock_nested().
4716 */
4717 ctx = READ_ONCE(child->ctx);
4718 /*
4719 * Since child_mutex nests inside ctx::mutex, we must jump
4720 * through hoops. We start by grabbing a reference on the ctx.
4721 *
4722 * Since the event cannot get freed while we hold the
4723 * child_mutex, the context must also exist and have a !0
4724 * reference count.
4725 */
4726 get_ctx(ctx);
4727
4728 /*
4729 * Now that we have a ctx ref, we can drop child_mutex, and
4730 * acquire ctx::mutex without fear of it going away. Then we
4731 * can re-acquire child_mutex.
4732 */
4733 mutex_unlock(&event->child_mutex);
4734 mutex_lock(&ctx->mutex);
4735 mutex_lock(&event->child_mutex);
4736
4737 /*
4738 * Now that we hold ctx::mutex and child_mutex, revalidate our
4739 * state, if child is still the first entry, it didn't get freed
4740 * and we can continue doing so.
4741 */
4742 tmp = list_first_entry_or_null(&event->child_list,
4743 struct perf_event, child_list);
4744 if (tmp == child) {
4745 perf_remove_from_context(child, DETACH_GROUP);
4746 list_move(&child->child_list, &free_list);
4747 /*
4748 * This matches the refcount bump in inherit_event();
4749 * this can't be the last reference.
4750 */
4751 put_event(event);
4752 }
4753
4754 mutex_unlock(&event->child_mutex);
4755 mutex_unlock(&ctx->mutex);
4756 put_ctx(ctx);
4757 goto again;
4758 }
4759 mutex_unlock(&event->child_mutex);
4760
4761 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4762 void *var = &child->ctx->refcount;
4763
4764 list_del(&child->child_list);
4765 free_event(child);
4766
4767 /*
4768 * Wake any perf_event_free_task() waiting for this event to be
4769 * freed.
4770 */
4771 smp_mb(); /* pairs with wait_var_event() */
4772 wake_up_var(var);
4773 }
4774
4775no_ctx:
4776 put_event(event); /* Must be the 'last' reference */
4777 return 0;
4778}
4779EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4780
4781/*
4782 * Called when the last reference to the file is gone.
4783 */
4784static int perf_release(struct inode *inode, struct file *file)
4785{
4786 perf_event_release_kernel(file->private_data);
4787 return 0;
4788}
4789
4790static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4791{
4792 struct perf_event *child;
4793 u64 total = 0;
4794
4795 *enabled = 0;
4796 *running = 0;
4797
4798 mutex_lock(&event->child_mutex);
4799
4800 (void)perf_event_read(event, false);
4801 total += perf_event_count(event);
4802
4803 *enabled += event->total_time_enabled +
4804 atomic64_read(&event->child_total_time_enabled);
4805 *running += event->total_time_running +
4806 atomic64_read(&event->child_total_time_running);
4807
4808 list_for_each_entry(child, &event->child_list, child_list) {
4809 (void)perf_event_read(child, false);
4810 total += perf_event_count(child);
4811 *enabled += child->total_time_enabled;
4812 *running += child->total_time_running;
4813 }
4814 mutex_unlock(&event->child_mutex);
4815
4816 return total;
4817}
4818
4819u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4820{
4821 struct perf_event_context *ctx;
4822 u64 count;
4823
4824 ctx = perf_event_ctx_lock(event);
4825 count = __perf_event_read_value(event, enabled, running);
4826 perf_event_ctx_unlock(event, ctx);
4827
4828 return count;
4829}
4830EXPORT_SYMBOL_GPL(perf_event_read_value);
4831
4832static int __perf_read_group_add(struct perf_event *leader,
4833 u64 read_format, u64 *values)
4834{
4835 struct perf_event_context *ctx = leader->ctx;
4836 struct perf_event *sub;
4837 unsigned long flags;
4838 int n = 1; /* skip @nr */
4839 int ret;
4840
4841 ret = perf_event_read(leader, true);
4842 if (ret)
4843 return ret;
4844
4845 raw_spin_lock_irqsave(&ctx->lock, flags);
4846
4847 /*
4848 * Since we co-schedule groups, {enabled,running} times of siblings
4849 * will be identical to those of the leader, so we only publish one
4850 * set.
4851 */
4852 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4853 values[n++] += leader->total_time_enabled +
4854 atomic64_read(&leader->child_total_time_enabled);
4855 }
4856
4857 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4858 values[n++] += leader->total_time_running +
4859 atomic64_read(&leader->child_total_time_running);
4860 }
4861
4862 /*
4863 * Write {count,id} tuples for every sibling.
4864 */
4865 values[n++] += perf_event_count(leader);
4866 if (read_format & PERF_FORMAT_ID)
4867 values[n++] = primary_event_id(leader);
4868
4869 for_each_sibling_event(sub, leader) {
4870 values[n++] += perf_event_count(sub);
4871 if (read_format & PERF_FORMAT_ID)
4872 values[n++] = primary_event_id(sub);
4873 }
4874
4875 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4876 return 0;
4877}
4878
4879static int perf_read_group(struct perf_event *event,
4880 u64 read_format, char __user *buf)
4881{
4882 struct perf_event *leader = event->group_leader, *child;
4883 struct perf_event_context *ctx = leader->ctx;
4884 int ret;
4885 u64 *values;
4886
4887 lockdep_assert_held(&ctx->mutex);
4888
4889 values = kzalloc(event->read_size, GFP_KERNEL);
4890 if (!values)
4891 return -ENOMEM;
4892
4893 values[0] = 1 + leader->nr_siblings;
4894
4895 /*
4896 * By locking the child_mutex of the leader we effectively
4897 * lock the child list of all siblings.. XXX explain how.
4898 */
4899 mutex_lock(&leader->child_mutex);
4900
4901 ret = __perf_read_group_add(leader, read_format, values);
4902 if (ret)
4903 goto unlock;
4904
4905 list_for_each_entry(child, &leader->child_list, child_list) {
4906 ret = __perf_read_group_add(child, read_format, values);
4907 if (ret)
4908 goto unlock;
4909 }
4910
4911 mutex_unlock(&leader->child_mutex);
4912
4913 ret = event->read_size;
4914 if (copy_to_user(buf, values, event->read_size))
4915 ret = -EFAULT;
4916 goto out;
4917
4918unlock:
4919 mutex_unlock(&leader->child_mutex);
4920out:
4921 kfree(values);
4922 return ret;
4923}
4924
4925static int perf_read_one(struct perf_event *event,
4926 u64 read_format, char __user *buf)
4927{
4928 u64 enabled, running;
4929 u64 values[4];
4930 int n = 0;
4931
4932 values[n++] = __perf_event_read_value(event, &enabled, &running);
4933 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4934 values[n++] = enabled;
4935 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4936 values[n++] = running;
4937 if (read_format & PERF_FORMAT_ID)
4938 values[n++] = primary_event_id(event);
4939
4940 if (copy_to_user(buf, values, n * sizeof(u64)))
4941 return -EFAULT;
4942
4943 return n * sizeof(u64);
4944}
4945
4946static bool is_event_hup(struct perf_event *event)
4947{
4948 bool no_children;
4949
4950 if (event->state > PERF_EVENT_STATE_EXIT)
4951 return false;
4952
4953 mutex_lock(&event->child_mutex);
4954 no_children = list_empty(&event->child_list);
4955 mutex_unlock(&event->child_mutex);
4956 return no_children;
4957}
4958
4959/*
4960 * Read the performance event - simple non blocking version for now
4961 */
4962static ssize_t
4963__perf_read(struct perf_event *event, char __user *buf, size_t count)
4964{
4965 u64 read_format = event->attr.read_format;
4966 int ret;
4967
4968 /*
4969 * Return end-of-file for a read on an event that is in
4970 * error state (i.e. because it was pinned but it couldn't be
4971 * scheduled on to the CPU at some point).
4972 */
4973 if (event->state == PERF_EVENT_STATE_ERROR)
4974 return 0;
4975
4976 if (count < event->read_size)
4977 return -ENOSPC;
4978
4979 WARN_ON_ONCE(event->ctx->parent_ctx);
4980 if (read_format & PERF_FORMAT_GROUP)
4981 ret = perf_read_group(event, read_format, buf);
4982 else
4983 ret = perf_read_one(event, read_format, buf);
4984
4985 return ret;
4986}
4987
4988static ssize_t
4989perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4990{
4991 struct perf_event *event = file->private_data;
4992 struct perf_event_context *ctx;
4993 int ret;
4994
4995 ctx = perf_event_ctx_lock(event);
4996 ret = __perf_read(event, buf, count);
4997 perf_event_ctx_unlock(event, ctx);
4998
4999 return ret;
5000}
5001
5002static __poll_t perf_poll(struct file *file, poll_table *wait)
5003{
5004 struct perf_event *event = file->private_data;
5005 struct ring_buffer *rb;
5006 __poll_t events = EPOLLHUP;
5007
5008 poll_wait(file, &event->waitq, wait);
5009
5010 if (is_event_hup(event))
5011 return events;
5012
5013 /*
5014 * Pin the event->rb by taking event->mmap_mutex; otherwise
5015 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5016 */
5017 mutex_lock(&event->mmap_mutex);
5018 rb = event->rb;
5019 if (rb)
5020 events = atomic_xchg(&rb->poll, 0);
5021 mutex_unlock(&event->mmap_mutex);
5022 return events;
5023}
5024
5025static void _perf_event_reset(struct perf_event *event)
5026{
5027 (void)perf_event_read(event, false);
5028 local64_set(&event->count, 0);
5029 perf_event_update_userpage(event);
5030}
5031
5032/*
5033 * Holding the top-level event's child_mutex means that any
5034 * descendant process that has inherited this event will block
5035 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5036 * task existence requirements of perf_event_enable/disable.
5037 */
5038static void perf_event_for_each_child(struct perf_event *event,
5039 void (*func)(struct perf_event *))
5040{
5041 struct perf_event *child;
5042
5043 WARN_ON_ONCE(event->ctx->parent_ctx);
5044
5045 mutex_lock(&event->child_mutex);
5046 func(event);
5047 list_for_each_entry(child, &event->child_list, child_list)
5048 func(child);
5049 mutex_unlock(&event->child_mutex);
5050}
5051
5052static void perf_event_for_each(struct perf_event *event,
5053 void (*func)(struct perf_event *))
5054{
5055 struct perf_event_context *ctx = event->ctx;
5056 struct perf_event *sibling;
5057
5058 lockdep_assert_held(&ctx->mutex);
5059
5060 event = event->group_leader;
5061
5062 perf_event_for_each_child(event, func);
5063 for_each_sibling_event(sibling, event)
5064 perf_event_for_each_child(sibling, func);
5065}
5066
5067static void __perf_event_period(struct perf_event *event,
5068 struct perf_cpu_context *cpuctx,
5069 struct perf_event_context *ctx,
5070 void *info)
5071{
5072 u64 value = *((u64 *)info);
5073 bool active;
5074
5075 if (event->attr.freq) {
5076 event->attr.sample_freq = value;
5077 } else {
5078 event->attr.sample_period = value;
5079 event->hw.sample_period = value;
5080 }
5081
5082 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5083 if (active) {
5084 perf_pmu_disable(ctx->pmu);
5085 /*
5086 * We could be throttled; unthrottle now to avoid the tick
5087 * trying to unthrottle while we already re-started the event.
5088 */
5089 if (event->hw.interrupts == MAX_INTERRUPTS) {
5090 event->hw.interrupts = 0;
5091 perf_log_throttle(event, 1);
5092 }
5093 event->pmu->stop(event, PERF_EF_UPDATE);
5094 }
5095
5096 local64_set(&event->hw.period_left, 0);
5097
5098 if (active) {
5099 event->pmu->start(event, PERF_EF_RELOAD);
5100 perf_pmu_enable(ctx->pmu);
5101 }
5102}
5103
5104static int perf_event_check_period(struct perf_event *event, u64 value)
5105{
5106 return event->pmu->check_period(event, value);
5107}
5108
5109static int perf_event_period(struct perf_event *event, u64 __user *arg)
5110{
5111 u64 value;
5112
5113 if (!is_sampling_event(event))
5114 return -EINVAL;
5115
5116 if (copy_from_user(&value, arg, sizeof(value)))
5117 return -EFAULT;
5118
5119 if (!value)
5120 return -EINVAL;
5121
5122 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5123 return -EINVAL;
5124
5125 if (perf_event_check_period(event, value))
5126 return -EINVAL;
5127
5128 if (!event->attr.freq && (value & (1ULL << 63)))
5129 return -EINVAL;
5130
5131 event_function_call(event, __perf_event_period, &value);
5132
5133 return 0;
5134}
5135
5136static const struct file_operations perf_fops;
5137
5138static inline int perf_fget_light(int fd, struct fd *p)
5139{
5140 struct fd f = fdget(fd);
5141 if (!f.file)
5142 return -EBADF;
5143
5144 if (f.file->f_op != &perf_fops) {
5145 fdput(f);
5146 return -EBADF;
5147 }
5148 *p = f;
5149 return 0;
5150}
5151
5152static int perf_event_set_output(struct perf_event *event,
5153 struct perf_event *output_event);
5154static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5155static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5156static int perf_copy_attr(struct perf_event_attr __user *uattr,
5157 struct perf_event_attr *attr);
5158
5159static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5160{
5161 void (*func)(struct perf_event *);
5162 u32 flags = arg;
5163
5164 switch (cmd) {
5165 case PERF_EVENT_IOC_ENABLE:
5166 func = _perf_event_enable;
5167 break;
5168 case PERF_EVENT_IOC_DISABLE:
5169 func = _perf_event_disable;
5170 break;
5171 case PERF_EVENT_IOC_RESET:
5172 func = _perf_event_reset;
5173 break;
5174
5175 case PERF_EVENT_IOC_REFRESH:
5176 return _perf_event_refresh(event, arg);
5177
5178 case PERF_EVENT_IOC_PERIOD:
5179 return perf_event_period(event, (u64 __user *)arg);
5180
5181 case PERF_EVENT_IOC_ID:
5182 {
5183 u64 id = primary_event_id(event);
5184
5185 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5186 return -EFAULT;
5187 return 0;
5188 }
5189
5190 case PERF_EVENT_IOC_SET_OUTPUT:
5191 {
5192 int ret;
5193 if (arg != -1) {
5194 struct perf_event *output_event;
5195 struct fd output;
5196 ret = perf_fget_light(arg, &output);
5197 if (ret)
5198 return ret;
5199 output_event = output.file->private_data;
5200 ret = perf_event_set_output(event, output_event);
5201 fdput(output);
5202 } else {
5203 ret = perf_event_set_output(event, NULL);
5204 }
5205 return ret;
5206 }
5207
5208 case PERF_EVENT_IOC_SET_FILTER:
5209 return perf_event_set_filter(event, (void __user *)arg);
5210
5211 case PERF_EVENT_IOC_SET_BPF:
5212 return perf_event_set_bpf_prog(event, arg);
5213
5214 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5215 struct ring_buffer *rb;
5216
5217 rcu_read_lock();
5218 rb = rcu_dereference(event->rb);
5219 if (!rb || !rb->nr_pages) {
5220 rcu_read_unlock();
5221 return -EINVAL;
5222 }
5223 rb_toggle_paused(rb, !!arg);
5224 rcu_read_unlock();
5225 return 0;
5226 }
5227
5228 case PERF_EVENT_IOC_QUERY_BPF:
5229 return perf_event_query_prog_array(event, (void __user *)arg);
5230
5231 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5232 struct perf_event_attr new_attr;
5233 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5234 &new_attr);
5235
5236 if (err)
5237 return err;
5238
5239 return perf_event_modify_attr(event, &new_attr);
5240 }
5241 default:
5242 return -ENOTTY;
5243 }
5244
5245 if (flags & PERF_IOC_FLAG_GROUP)
5246 perf_event_for_each(event, func);
5247 else
5248 perf_event_for_each_child(event, func);
5249
5250 return 0;
5251}
5252
5253static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5254{
5255 struct perf_event *event = file->private_data;
5256 struct perf_event_context *ctx;
5257 long ret;
5258
5259 ctx = perf_event_ctx_lock(event);
5260 ret = _perf_ioctl(event, cmd, arg);
5261 perf_event_ctx_unlock(event, ctx);
5262
5263 return ret;
5264}
5265
5266#ifdef CONFIG_COMPAT
5267static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5268 unsigned long arg)
5269{
5270 switch (_IOC_NR(cmd)) {
5271 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5272 case _IOC_NR(PERF_EVENT_IOC_ID):
5273 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5274 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5275 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5276 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5277 cmd &= ~IOCSIZE_MASK;
5278 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5279 }
5280 break;
5281 }
5282 return perf_ioctl(file, cmd, arg);
5283}
5284#else
5285# define perf_compat_ioctl NULL
5286#endif
5287
5288int perf_event_task_enable(void)
5289{
5290 struct perf_event_context *ctx;
5291 struct perf_event *event;
5292
5293 mutex_lock(¤t->perf_event_mutex);
5294 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5295 ctx = perf_event_ctx_lock(event);
5296 perf_event_for_each_child(event, _perf_event_enable);
5297 perf_event_ctx_unlock(event, ctx);
5298 }
5299 mutex_unlock(¤t->perf_event_mutex);
5300
5301 return 0;
5302}
5303
5304int perf_event_task_disable(void)
5305{
5306 struct perf_event_context *ctx;
5307 struct perf_event *event;
5308
5309 mutex_lock(¤t->perf_event_mutex);
5310 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5311 ctx = perf_event_ctx_lock(event);
5312 perf_event_for_each_child(event, _perf_event_disable);
5313 perf_event_ctx_unlock(event, ctx);
5314 }
5315 mutex_unlock(¤t->perf_event_mutex);
5316
5317 return 0;
5318}
5319
5320static int perf_event_index(struct perf_event *event)
5321{
5322 if (event->hw.state & PERF_HES_STOPPED)
5323 return 0;
5324
5325 if (event->state != PERF_EVENT_STATE_ACTIVE)
5326 return 0;
5327
5328 return event->pmu->event_idx(event);
5329}
5330
5331static void calc_timer_values(struct perf_event *event,
5332 u64 *now,
5333 u64 *enabled,
5334 u64 *running)
5335{
5336 u64 ctx_time;
5337
5338 *now = perf_clock();
5339 ctx_time = event->shadow_ctx_time + *now;
5340 __perf_update_times(event, ctx_time, enabled, running);
5341}
5342
5343static void perf_event_init_userpage(struct perf_event *event)
5344{
5345 struct perf_event_mmap_page *userpg;
5346 struct ring_buffer *rb;
5347
5348 rcu_read_lock();
5349 rb = rcu_dereference(event->rb);
5350 if (!rb)
5351 goto unlock;
5352
5353 userpg = rb->user_page;
5354
5355 /* Allow new userspace to detect that bit 0 is deprecated */
5356 userpg->cap_bit0_is_deprecated = 1;
5357 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5358 userpg->data_offset = PAGE_SIZE;
5359 userpg->data_size = perf_data_size(rb);
5360
5361unlock:
5362 rcu_read_unlock();
5363}
5364
5365void __weak arch_perf_update_userpage(
5366 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5367{
5368}
5369
5370/*
5371 * Callers need to ensure there can be no nesting of this function, otherwise
5372 * the seqlock logic goes bad. We can not serialize this because the arch
5373 * code calls this from NMI context.
5374 */
5375void perf_event_update_userpage(struct perf_event *event)
5376{
5377 struct perf_event_mmap_page *userpg;
5378 struct ring_buffer *rb;
5379 u64 enabled, running, now;
5380
5381 rcu_read_lock();
5382 rb = rcu_dereference(event->rb);
5383 if (!rb)
5384 goto unlock;
5385
5386 /*
5387 * compute total_time_enabled, total_time_running
5388 * based on snapshot values taken when the event
5389 * was last scheduled in.
5390 *
5391 * we cannot simply called update_context_time()
5392 * because of locking issue as we can be called in
5393 * NMI context
5394 */
5395 calc_timer_values(event, &now, &enabled, &running);
5396
5397 userpg = rb->user_page;
5398 /*
5399 * Disable preemption to guarantee consistent time stamps are stored to
5400 * the user page.
5401 */
5402 preempt_disable();
5403 ++userpg->lock;
5404 barrier();
5405 userpg->index = perf_event_index(event);
5406 userpg->offset = perf_event_count(event);
5407 if (userpg->index)
5408 userpg->offset -= local64_read(&event->hw.prev_count);
5409
5410 userpg->time_enabled = enabled +
5411 atomic64_read(&event->child_total_time_enabled);
5412
5413 userpg->time_running = running +
5414 atomic64_read(&event->child_total_time_running);
5415
5416 arch_perf_update_userpage(event, userpg, now);
5417
5418 barrier();
5419 ++userpg->lock;
5420 preempt_enable();
5421unlock:
5422 rcu_read_unlock();
5423}
5424EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5425
5426static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5427{
5428 struct perf_event *event = vmf->vma->vm_file->private_data;
5429 struct ring_buffer *rb;
5430 vm_fault_t ret = VM_FAULT_SIGBUS;
5431
5432 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5433 if (vmf->pgoff == 0)
5434 ret = 0;
5435 return ret;
5436 }
5437
5438 rcu_read_lock();
5439 rb = rcu_dereference(event->rb);
5440 if (!rb)
5441 goto unlock;
5442
5443 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5444 goto unlock;
5445
5446 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5447 if (!vmf->page)
5448 goto unlock;
5449
5450 get_page(vmf->page);
5451 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5452 vmf->page->index = vmf->pgoff;
5453
5454 ret = 0;
5455unlock:
5456 rcu_read_unlock();
5457
5458 return ret;
5459}
5460
5461static void ring_buffer_attach(struct perf_event *event,
5462 struct ring_buffer *rb)
5463{
5464 struct ring_buffer *old_rb = NULL;
5465 unsigned long flags;
5466
5467 if (event->rb) {
5468 /*
5469 * Should be impossible, we set this when removing
5470 * event->rb_entry and wait/clear when adding event->rb_entry.
5471 */
5472 WARN_ON_ONCE(event->rcu_pending);
5473
5474 old_rb = event->rb;
5475 spin_lock_irqsave(&old_rb->event_lock, flags);
5476 list_del_rcu(&event->rb_entry);
5477 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5478
5479 event->rcu_batches = get_state_synchronize_rcu();
5480 event->rcu_pending = 1;
5481 }
5482
5483 if (rb) {
5484 if (event->rcu_pending) {
5485 cond_synchronize_rcu(event->rcu_batches);
5486 event->rcu_pending = 0;
5487 }
5488
5489 spin_lock_irqsave(&rb->event_lock, flags);
5490 list_add_rcu(&event->rb_entry, &rb->event_list);
5491 spin_unlock_irqrestore(&rb->event_lock, flags);
5492 }
5493
5494 /*
5495 * Avoid racing with perf_mmap_close(AUX): stop the event
5496 * before swizzling the event::rb pointer; if it's getting
5497 * unmapped, its aux_mmap_count will be 0 and it won't
5498 * restart. See the comment in __perf_pmu_output_stop().
5499 *
5500 * Data will inevitably be lost when set_output is done in
5501 * mid-air, but then again, whoever does it like this is
5502 * not in for the data anyway.
5503 */
5504 if (has_aux(event))
5505 perf_event_stop(event, 0);
5506
5507 rcu_assign_pointer(event->rb, rb);
5508
5509 if (old_rb) {
5510 ring_buffer_put(old_rb);
5511 /*
5512 * Since we detached before setting the new rb, so that we
5513 * could attach the new rb, we could have missed a wakeup.
5514 * Provide it now.
5515 */
5516 wake_up_all(&event->waitq);
5517 }
5518}
5519
5520static void ring_buffer_wakeup(struct perf_event *event)
5521{
5522 struct ring_buffer *rb;
5523
5524 rcu_read_lock();
5525 rb = rcu_dereference(event->rb);
5526 if (rb) {
5527 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5528 wake_up_all(&event->waitq);
5529 }
5530 rcu_read_unlock();
5531}
5532
5533struct ring_buffer *ring_buffer_get(struct perf_event *event)
5534{
5535 struct ring_buffer *rb;
5536
5537 rcu_read_lock();
5538 rb = rcu_dereference(event->rb);
5539 if (rb) {
5540 if (!refcount_inc_not_zero(&rb->refcount))
5541 rb = NULL;
5542 }
5543 rcu_read_unlock();
5544
5545 return rb;
5546}
5547
5548void ring_buffer_put(struct ring_buffer *rb)
5549{
5550 if (!refcount_dec_and_test(&rb->refcount))
5551 return;
5552
5553 WARN_ON_ONCE(!list_empty(&rb->event_list));
5554
5555 call_rcu(&rb->rcu_head, rb_free_rcu);
5556}
5557
5558static void perf_mmap_open(struct vm_area_struct *vma)
5559{
5560 struct perf_event *event = vma->vm_file->private_data;
5561
5562 atomic_inc(&event->mmap_count);
5563 atomic_inc(&event->rb->mmap_count);
5564
5565 if (vma->vm_pgoff)
5566 atomic_inc(&event->rb->aux_mmap_count);
5567
5568 if (event->pmu->event_mapped)
5569 event->pmu->event_mapped(event, vma->vm_mm);
5570}
5571
5572static void perf_pmu_output_stop(struct perf_event *event);
5573
5574/*
5575 * A buffer can be mmap()ed multiple times; either directly through the same
5576 * event, or through other events by use of perf_event_set_output().
5577 *
5578 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5579 * the buffer here, where we still have a VM context. This means we need
5580 * to detach all events redirecting to us.
5581 */
5582static void perf_mmap_close(struct vm_area_struct *vma)
5583{
5584 struct perf_event *event = vma->vm_file->private_data;
5585
5586 struct ring_buffer *rb = ring_buffer_get(event);
5587 struct user_struct *mmap_user = rb->mmap_user;
5588 int mmap_locked = rb->mmap_locked;
5589 unsigned long size = perf_data_size(rb);
5590
5591 if (event->pmu->event_unmapped)
5592 event->pmu->event_unmapped(event, vma->vm_mm);
5593
5594 /*
5595 * rb->aux_mmap_count will always drop before rb->mmap_count and
5596 * event->mmap_count, so it is ok to use event->mmap_mutex to
5597 * serialize with perf_mmap here.
5598 */
5599 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5600 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5601 /*
5602 * Stop all AUX events that are writing to this buffer,
5603 * so that we can free its AUX pages and corresponding PMU
5604 * data. Note that after rb::aux_mmap_count dropped to zero,
5605 * they won't start any more (see perf_aux_output_begin()).
5606 */
5607 perf_pmu_output_stop(event);
5608
5609 /* now it's safe to free the pages */
5610 if (!rb->aux_mmap_locked)
5611 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5612 else
5613 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
5614
5615 /* this has to be the last one */
5616 rb_free_aux(rb);
5617 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
5618
5619 mutex_unlock(&event->mmap_mutex);
5620 }
5621
5622 atomic_dec(&rb->mmap_count);
5623
5624 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5625 goto out_put;
5626
5627 ring_buffer_attach(event, NULL);
5628 mutex_unlock(&event->mmap_mutex);
5629
5630 /* If there's still other mmap()s of this buffer, we're done. */
5631 if (atomic_read(&rb->mmap_count))
5632 goto out_put;
5633
5634 /*
5635 * No other mmap()s, detach from all other events that might redirect
5636 * into the now unreachable buffer. Somewhat complicated by the
5637 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5638 */
5639again:
5640 rcu_read_lock();
5641 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5642 if (!atomic_long_inc_not_zero(&event->refcount)) {
5643 /*
5644 * This event is en-route to free_event() which will
5645 * detach it and remove it from the list.
5646 */
5647 continue;
5648 }
5649 rcu_read_unlock();
5650
5651 mutex_lock(&event->mmap_mutex);
5652 /*
5653 * Check we didn't race with perf_event_set_output() which can
5654 * swizzle the rb from under us while we were waiting to
5655 * acquire mmap_mutex.
5656 *
5657 * If we find a different rb; ignore this event, a next
5658 * iteration will no longer find it on the list. We have to
5659 * still restart the iteration to make sure we're not now
5660 * iterating the wrong list.
5661 */
5662 if (event->rb == rb)
5663 ring_buffer_attach(event, NULL);
5664
5665 mutex_unlock(&event->mmap_mutex);
5666 put_event(event);
5667
5668 /*
5669 * Restart the iteration; either we're on the wrong list or
5670 * destroyed its integrity by doing a deletion.
5671 */
5672 goto again;
5673 }
5674 rcu_read_unlock();
5675
5676 /*
5677 * It could be there's still a few 0-ref events on the list; they'll
5678 * get cleaned up by free_event() -- they'll also still have their
5679 * ref on the rb and will free it whenever they are done with it.
5680 *
5681 * Aside from that, this buffer is 'fully' detached and unmapped,
5682 * undo the VM accounting.
5683 */
5684
5685 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
5686 &mmap_user->locked_vm);
5687 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
5688 free_uid(mmap_user);
5689
5690out_put:
5691 ring_buffer_put(rb); /* could be last */
5692}
5693
5694static const struct vm_operations_struct perf_mmap_vmops = {
5695 .open = perf_mmap_open,
5696 .close = perf_mmap_close, /* non mergeable */
5697 .fault = perf_mmap_fault,
5698 .page_mkwrite = perf_mmap_fault,
5699};
5700
5701static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5702{
5703 struct perf_event *event = file->private_data;
5704 unsigned long user_locked, user_lock_limit;
5705 struct user_struct *user = current_user();
5706 unsigned long locked, lock_limit;
5707 struct ring_buffer *rb = NULL;
5708 unsigned long vma_size;
5709 unsigned long nr_pages;
5710 long user_extra = 0, extra = 0;
5711 int ret = 0, flags = 0;
5712
5713 /*
5714 * Don't allow mmap() of inherited per-task counters. This would
5715 * create a performance issue due to all children writing to the
5716 * same rb.
5717 */
5718 if (event->cpu == -1 && event->attr.inherit)
5719 return -EINVAL;
5720
5721 if (!(vma->vm_flags & VM_SHARED))
5722 return -EINVAL;
5723
5724 vma_size = vma->vm_end - vma->vm_start;
5725
5726 if (vma->vm_pgoff == 0) {
5727 nr_pages = (vma_size / PAGE_SIZE) - 1;
5728 } else {
5729 /*
5730 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5731 * mapped, all subsequent mappings should have the same size
5732 * and offset. Must be above the normal perf buffer.
5733 */
5734 u64 aux_offset, aux_size;
5735
5736 if (!event->rb)
5737 return -EINVAL;
5738
5739 nr_pages = vma_size / PAGE_SIZE;
5740
5741 mutex_lock(&event->mmap_mutex);
5742 ret = -EINVAL;
5743
5744 rb = event->rb;
5745 if (!rb)
5746 goto aux_unlock;
5747
5748 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5749 aux_size = READ_ONCE(rb->user_page->aux_size);
5750
5751 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5752 goto aux_unlock;
5753
5754 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5755 goto aux_unlock;
5756
5757 /* already mapped with a different offset */
5758 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5759 goto aux_unlock;
5760
5761 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5762 goto aux_unlock;
5763
5764 /* already mapped with a different size */
5765 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5766 goto aux_unlock;
5767
5768 if (!is_power_of_2(nr_pages))
5769 goto aux_unlock;
5770
5771 if (!atomic_inc_not_zero(&rb->mmap_count))
5772 goto aux_unlock;
5773
5774 if (rb_has_aux(rb)) {
5775 atomic_inc(&rb->aux_mmap_count);
5776 ret = 0;
5777 goto unlock;
5778 }
5779
5780 atomic_set(&rb->aux_mmap_count, 1);
5781 user_extra = nr_pages;
5782
5783 goto accounting;
5784 }
5785
5786 /*
5787 * If we have rb pages ensure they're a power-of-two number, so we
5788 * can do bitmasks instead of modulo.
5789 */
5790 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5791 return -EINVAL;
5792
5793 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5794 return -EINVAL;
5795
5796 WARN_ON_ONCE(event->ctx->parent_ctx);
5797again:
5798 mutex_lock(&event->mmap_mutex);
5799 if (event->rb) {
5800 if (event->rb->nr_pages != nr_pages) {
5801 ret = -EINVAL;
5802 goto unlock;
5803 }
5804
5805 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5806 /*
5807 * Raced against perf_mmap_close() through
5808 * perf_event_set_output(). Try again, hope for better
5809 * luck.
5810 */
5811 mutex_unlock(&event->mmap_mutex);
5812 goto again;
5813 }
5814
5815 goto unlock;
5816 }
5817
5818 user_extra = nr_pages + 1;
5819
5820accounting:
5821 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5822
5823 /*
5824 * Increase the limit linearly with more CPUs:
5825 */
5826 user_lock_limit *= num_online_cpus();
5827
5828 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5829
5830 if (user_locked <= user_lock_limit) {
5831 /* charge all to locked_vm */
5832 } else if (atomic_long_read(&user->locked_vm) >= user_lock_limit) {
5833 /* charge all to pinned_vm */
5834 extra = user_extra;
5835 user_extra = 0;
5836 } else {
5837 /*
5838 * charge locked_vm until it hits user_lock_limit;
5839 * charge the rest from pinned_vm
5840 */
5841 extra = user_locked - user_lock_limit;
5842 user_extra -= extra;
5843 }
5844
5845 lock_limit = rlimit(RLIMIT_MEMLOCK);
5846 lock_limit >>= PAGE_SHIFT;
5847 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
5848
5849 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5850 !capable(CAP_IPC_LOCK)) {
5851 ret = -EPERM;
5852 goto unlock;
5853 }
5854
5855 WARN_ON(!rb && event->rb);
5856
5857 if (vma->vm_flags & VM_WRITE)
5858 flags |= RING_BUFFER_WRITABLE;
5859
5860 if (!rb) {
5861 rb = rb_alloc(nr_pages,
5862 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5863 event->cpu, flags);
5864
5865 if (!rb) {
5866 ret = -ENOMEM;
5867 goto unlock;
5868 }
5869
5870 atomic_set(&rb->mmap_count, 1);
5871 rb->mmap_user = get_current_user();
5872 rb->mmap_locked = extra;
5873
5874 ring_buffer_attach(event, rb);
5875
5876 perf_event_init_userpage(event);
5877 perf_event_update_userpage(event);
5878 } else {
5879 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5880 event->attr.aux_watermark, flags);
5881 if (!ret)
5882 rb->aux_mmap_locked = extra;
5883 }
5884
5885unlock:
5886 if (!ret) {
5887 atomic_long_add(user_extra, &user->locked_vm);
5888 atomic64_add(extra, &vma->vm_mm->pinned_vm);
5889
5890 atomic_inc(&event->mmap_count);
5891 } else if (rb) {
5892 atomic_dec(&rb->mmap_count);
5893 }
5894aux_unlock:
5895 mutex_unlock(&event->mmap_mutex);
5896
5897 /*
5898 * Since pinned accounting is per vm we cannot allow fork() to copy our
5899 * vma.
5900 */
5901 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5902 vma->vm_ops = &perf_mmap_vmops;
5903
5904 if (event->pmu->event_mapped)
5905 event->pmu->event_mapped(event, vma->vm_mm);
5906
5907 return ret;
5908}
5909
5910static int perf_fasync(int fd, struct file *filp, int on)
5911{
5912 struct inode *inode = file_inode(filp);
5913 struct perf_event *event = filp->private_data;
5914 int retval;
5915
5916 inode_lock(inode);
5917 retval = fasync_helper(fd, filp, on, &event->fasync);
5918 inode_unlock(inode);
5919
5920 if (retval < 0)
5921 return retval;
5922
5923 return 0;
5924}
5925
5926static const struct file_operations perf_fops = {
5927 .llseek = no_llseek,
5928 .release = perf_release,
5929 .read = perf_read,
5930 .poll = perf_poll,
5931 .unlocked_ioctl = perf_ioctl,
5932 .compat_ioctl = perf_compat_ioctl,
5933 .mmap = perf_mmap,
5934 .fasync = perf_fasync,
5935};
5936
5937/*
5938 * Perf event wakeup
5939 *
5940 * If there's data, ensure we set the poll() state and publish everything
5941 * to user-space before waking everybody up.
5942 */
5943
5944static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5945{
5946 /* only the parent has fasync state */
5947 if (event->parent)
5948 event = event->parent;
5949 return &event->fasync;
5950}
5951
5952void perf_event_wakeup(struct perf_event *event)
5953{
5954 ring_buffer_wakeup(event);
5955
5956 if (event->pending_kill) {
5957 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5958 event->pending_kill = 0;
5959 }
5960}
5961
5962static void perf_pending_event_disable(struct perf_event *event)
5963{
5964 int cpu = READ_ONCE(event->pending_disable);
5965
5966 if (cpu < 0)
5967 return;
5968
5969 if (cpu == smp_processor_id()) {
5970 WRITE_ONCE(event->pending_disable, -1);
5971 perf_event_disable_local(event);
5972 return;
5973 }
5974
5975 /*
5976 * CPU-A CPU-B
5977 *
5978 * perf_event_disable_inatomic()
5979 * @pending_disable = CPU-A;
5980 * irq_work_queue();
5981 *
5982 * sched-out
5983 * @pending_disable = -1;
5984 *
5985 * sched-in
5986 * perf_event_disable_inatomic()
5987 * @pending_disable = CPU-B;
5988 * irq_work_queue(); // FAILS
5989 *
5990 * irq_work_run()
5991 * perf_pending_event()
5992 *
5993 * But the event runs on CPU-B and wants disabling there.
5994 */
5995 irq_work_queue_on(&event->pending, cpu);
5996}
5997
5998static void perf_pending_event(struct irq_work *entry)
5999{
6000 struct perf_event *event = container_of(entry, struct perf_event, pending);
6001 int rctx;
6002
6003 rctx = perf_swevent_get_recursion_context();
6004 /*
6005 * If we 'fail' here, that's OK, it means recursion is already disabled
6006 * and we won't recurse 'further'.
6007 */
6008
6009 perf_pending_event_disable(event);
6010
6011 if (event->pending_wakeup) {
6012 event->pending_wakeup = 0;
6013 perf_event_wakeup(event);
6014 }
6015
6016 if (rctx >= 0)
6017 perf_swevent_put_recursion_context(rctx);
6018}
6019
6020/*
6021 * We assume there is only KVM supporting the callbacks.
6022 * Later on, we might change it to a list if there is
6023 * another virtualization implementation supporting the callbacks.
6024 */
6025struct perf_guest_info_callbacks *perf_guest_cbs;
6026
6027int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6028{
6029 perf_guest_cbs = cbs;
6030 return 0;
6031}
6032EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6033
6034int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6035{
6036 perf_guest_cbs = NULL;
6037 return 0;
6038}
6039EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6040
6041static void
6042perf_output_sample_regs(struct perf_output_handle *handle,
6043 struct pt_regs *regs, u64 mask)
6044{
6045 int bit;
6046 DECLARE_BITMAP(_mask, 64);
6047
6048 bitmap_from_u64(_mask, mask);
6049 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6050 u64 val;
6051
6052 val = perf_reg_value(regs, bit);
6053 perf_output_put(handle, val);
6054 }
6055}
6056
6057static void perf_sample_regs_user(struct perf_regs *regs_user,
6058 struct pt_regs *regs,
6059 struct pt_regs *regs_user_copy)
6060{
6061 if (user_mode(regs)) {
6062 regs_user->abi = perf_reg_abi(current);
6063 regs_user->regs = regs;
6064 } else if (!(current->flags & PF_KTHREAD)) {
6065 perf_get_regs_user(regs_user, regs, regs_user_copy);
6066 } else {
6067 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6068 regs_user->regs = NULL;
6069 }
6070}
6071
6072static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6073 struct pt_regs *regs)
6074{
6075 regs_intr->regs = regs;
6076 regs_intr->abi = perf_reg_abi(current);
6077}
6078
6079
6080/*
6081 * Get remaining task size from user stack pointer.
6082 *
6083 * It'd be better to take stack vma map and limit this more
6084 * precisely, but there's no way to get it safely under interrupt,
6085 * so using TASK_SIZE as limit.
6086 */
6087static u64 perf_ustack_task_size(struct pt_regs *regs)
6088{
6089 unsigned long addr = perf_user_stack_pointer(regs);
6090
6091 if (!addr || addr >= TASK_SIZE)
6092 return 0;
6093
6094 return TASK_SIZE - addr;
6095}
6096
6097static u16
6098perf_sample_ustack_size(u16 stack_size, u16 header_size,
6099 struct pt_regs *regs)
6100{
6101 u64 task_size;
6102
6103 /* No regs, no stack pointer, no dump. */
6104 if (!regs)
6105 return 0;
6106
6107 /*
6108 * Check if we fit in with the requested stack size into the:
6109 * - TASK_SIZE
6110 * If we don't, we limit the size to the TASK_SIZE.
6111 *
6112 * - remaining sample size
6113 * If we don't, we customize the stack size to
6114 * fit in to the remaining sample size.
6115 */
6116
6117 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6118 stack_size = min(stack_size, (u16) task_size);
6119
6120 /* Current header size plus static size and dynamic size. */
6121 header_size += 2 * sizeof(u64);
6122
6123 /* Do we fit in with the current stack dump size? */
6124 if ((u16) (header_size + stack_size) < header_size) {
6125 /*
6126 * If we overflow the maximum size for the sample,
6127 * we customize the stack dump size to fit in.
6128 */
6129 stack_size = USHRT_MAX - header_size - sizeof(u64);
6130 stack_size = round_up(stack_size, sizeof(u64));
6131 }
6132
6133 return stack_size;
6134}
6135
6136static void
6137perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6138 struct pt_regs *regs)
6139{
6140 /* Case of a kernel thread, nothing to dump */
6141 if (!regs) {
6142 u64 size = 0;
6143 perf_output_put(handle, size);
6144 } else {
6145 unsigned long sp;
6146 unsigned int rem;
6147 u64 dyn_size;
6148 mm_segment_t fs;
6149
6150 /*
6151 * We dump:
6152 * static size
6153 * - the size requested by user or the best one we can fit
6154 * in to the sample max size
6155 * data
6156 * - user stack dump data
6157 * dynamic size
6158 * - the actual dumped size
6159 */
6160
6161 /* Static size. */
6162 perf_output_put(handle, dump_size);
6163
6164 /* Data. */
6165 sp = perf_user_stack_pointer(regs);
6166 fs = get_fs();
6167 set_fs(USER_DS);
6168 rem = __output_copy_user(handle, (void *) sp, dump_size);
6169 set_fs(fs);
6170 dyn_size = dump_size - rem;
6171
6172 perf_output_skip(handle, rem);
6173
6174 /* Dynamic size. */
6175 perf_output_put(handle, dyn_size);
6176 }
6177}
6178
6179static void __perf_event_header__init_id(struct perf_event_header *header,
6180 struct perf_sample_data *data,
6181 struct perf_event *event)
6182{
6183 u64 sample_type = event->attr.sample_type;
6184
6185 data->type = sample_type;
6186 header->size += event->id_header_size;
6187
6188 if (sample_type & PERF_SAMPLE_TID) {
6189 /* namespace issues */
6190 data->tid_entry.pid = perf_event_pid(event, current);
6191 data->tid_entry.tid = perf_event_tid(event, current);
6192 }
6193
6194 if (sample_type & PERF_SAMPLE_TIME)
6195 data->time = perf_event_clock(event);
6196
6197 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6198 data->id = primary_event_id(event);
6199
6200 if (sample_type & PERF_SAMPLE_STREAM_ID)
6201 data->stream_id = event->id;
6202
6203 if (sample_type & PERF_SAMPLE_CPU) {
6204 data->cpu_entry.cpu = raw_smp_processor_id();
6205 data->cpu_entry.reserved = 0;
6206 }
6207}
6208
6209void perf_event_header__init_id(struct perf_event_header *header,
6210 struct perf_sample_data *data,
6211 struct perf_event *event)
6212{
6213 if (event->attr.sample_id_all)
6214 __perf_event_header__init_id(header, data, event);
6215}
6216
6217static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6218 struct perf_sample_data *data)
6219{
6220 u64 sample_type = data->type;
6221
6222 if (sample_type & PERF_SAMPLE_TID)
6223 perf_output_put(handle, data->tid_entry);
6224
6225 if (sample_type & PERF_SAMPLE_TIME)
6226 perf_output_put(handle, data->time);
6227
6228 if (sample_type & PERF_SAMPLE_ID)
6229 perf_output_put(handle, data->id);
6230
6231 if (sample_type & PERF_SAMPLE_STREAM_ID)
6232 perf_output_put(handle, data->stream_id);
6233
6234 if (sample_type & PERF_SAMPLE_CPU)
6235 perf_output_put(handle, data->cpu_entry);
6236
6237 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6238 perf_output_put(handle, data->id);
6239}
6240
6241void perf_event__output_id_sample(struct perf_event *event,
6242 struct perf_output_handle *handle,
6243 struct perf_sample_data *sample)
6244{
6245 if (event->attr.sample_id_all)
6246 __perf_event__output_id_sample(handle, sample);
6247}
6248
6249static void perf_output_read_one(struct perf_output_handle *handle,
6250 struct perf_event *event,
6251 u64 enabled, u64 running)
6252{
6253 u64 read_format = event->attr.read_format;
6254 u64 values[4];
6255 int n = 0;
6256
6257 values[n++] = perf_event_count(event);
6258 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6259 values[n++] = enabled +
6260 atomic64_read(&event->child_total_time_enabled);
6261 }
6262 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6263 values[n++] = running +
6264 atomic64_read(&event->child_total_time_running);
6265 }
6266 if (read_format & PERF_FORMAT_ID)
6267 values[n++] = primary_event_id(event);
6268
6269 __output_copy(handle, values, n * sizeof(u64));
6270}
6271
6272static void perf_output_read_group(struct perf_output_handle *handle,
6273 struct perf_event *event,
6274 u64 enabled, u64 running)
6275{
6276 struct perf_event *leader = event->group_leader, *sub;
6277 u64 read_format = event->attr.read_format;
6278 u64 values[5];
6279 int n = 0;
6280
6281 values[n++] = 1 + leader->nr_siblings;
6282
6283 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6284 values[n++] = enabled;
6285
6286 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6287 values[n++] = running;
6288
6289 if ((leader != event) &&
6290 (leader->state == PERF_EVENT_STATE_ACTIVE))
6291 leader->pmu->read(leader);
6292
6293 values[n++] = perf_event_count(leader);
6294 if (read_format & PERF_FORMAT_ID)
6295 values[n++] = primary_event_id(leader);
6296
6297 __output_copy(handle, values, n * sizeof(u64));
6298
6299 for_each_sibling_event(sub, leader) {
6300 n = 0;
6301
6302 if ((sub != event) &&
6303 (sub->state == PERF_EVENT_STATE_ACTIVE))
6304 sub->pmu->read(sub);
6305
6306 values[n++] = perf_event_count(sub);
6307 if (read_format & PERF_FORMAT_ID)
6308 values[n++] = primary_event_id(sub);
6309
6310 __output_copy(handle, values, n * sizeof(u64));
6311 }
6312}
6313
6314#define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6315 PERF_FORMAT_TOTAL_TIME_RUNNING)
6316
6317/*
6318 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6319 *
6320 * The problem is that its both hard and excessively expensive to iterate the
6321 * child list, not to mention that its impossible to IPI the children running
6322 * on another CPU, from interrupt/NMI context.
6323 */
6324static void perf_output_read(struct perf_output_handle *handle,
6325 struct perf_event *event)
6326{
6327 u64 enabled = 0, running = 0, now;
6328 u64 read_format = event->attr.read_format;
6329
6330 /*
6331 * compute total_time_enabled, total_time_running
6332 * based on snapshot values taken when the event
6333 * was last scheduled in.
6334 *
6335 * we cannot simply called update_context_time()
6336 * because of locking issue as we are called in
6337 * NMI context
6338 */
6339 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6340 calc_timer_values(event, &now, &enabled, &running);
6341
6342 if (event->attr.read_format & PERF_FORMAT_GROUP)
6343 perf_output_read_group(handle, event, enabled, running);
6344 else
6345 perf_output_read_one(handle, event, enabled, running);
6346}
6347
6348void perf_output_sample(struct perf_output_handle *handle,
6349 struct perf_event_header *header,
6350 struct perf_sample_data *data,
6351 struct perf_event *event)
6352{
6353 u64 sample_type = data->type;
6354
6355 perf_output_put(handle, *header);
6356
6357 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6358 perf_output_put(handle, data->id);
6359
6360 if (sample_type & PERF_SAMPLE_IP)
6361 perf_output_put(handle, data->ip);
6362
6363 if (sample_type & PERF_SAMPLE_TID)
6364 perf_output_put(handle, data->tid_entry);
6365
6366 if (sample_type & PERF_SAMPLE_TIME)
6367 perf_output_put(handle, data->time);
6368
6369 if (sample_type & PERF_SAMPLE_ADDR)
6370 perf_output_put(handle, data->addr);
6371
6372 if (sample_type & PERF_SAMPLE_ID)
6373 perf_output_put(handle, data->id);
6374
6375 if (sample_type & PERF_SAMPLE_STREAM_ID)
6376 perf_output_put(handle, data->stream_id);
6377
6378 if (sample_type & PERF_SAMPLE_CPU)
6379 perf_output_put(handle, data->cpu_entry);
6380
6381 if (sample_type & PERF_SAMPLE_PERIOD)
6382 perf_output_put(handle, data->period);
6383
6384 if (sample_type & PERF_SAMPLE_READ)
6385 perf_output_read(handle, event);
6386
6387 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6388 int size = 1;
6389
6390 size += data->callchain->nr;
6391 size *= sizeof(u64);
6392 __output_copy(handle, data->callchain, size);
6393 }
6394
6395 if (sample_type & PERF_SAMPLE_RAW) {
6396 struct perf_raw_record *raw = data->raw;
6397
6398 if (raw) {
6399 struct perf_raw_frag *frag = &raw->frag;
6400
6401 perf_output_put(handle, raw->size);
6402 do {
6403 if (frag->copy) {
6404 __output_custom(handle, frag->copy,
6405 frag->data, frag->size);
6406 } else {
6407 __output_copy(handle, frag->data,
6408 frag->size);
6409 }
6410 if (perf_raw_frag_last(frag))
6411 break;
6412 frag = frag->next;
6413 } while (1);
6414 if (frag->pad)
6415 __output_skip(handle, NULL, frag->pad);
6416 } else {
6417 struct {
6418 u32 size;
6419 u32 data;
6420 } raw = {
6421 .size = sizeof(u32),
6422 .data = 0,
6423 };
6424 perf_output_put(handle, raw);
6425 }
6426 }
6427
6428 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6429 if (data->br_stack) {
6430 size_t size;
6431
6432 size = data->br_stack->nr
6433 * sizeof(struct perf_branch_entry);
6434
6435 perf_output_put(handle, data->br_stack->nr);
6436 perf_output_copy(handle, data->br_stack->entries, size);
6437 } else {
6438 /*
6439 * we always store at least the value of nr
6440 */
6441 u64 nr = 0;
6442 perf_output_put(handle, nr);
6443 }
6444 }
6445
6446 if (sample_type & PERF_SAMPLE_REGS_USER) {
6447 u64 abi = data->regs_user.abi;
6448
6449 /*
6450 * If there are no regs to dump, notice it through
6451 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6452 */
6453 perf_output_put(handle, abi);
6454
6455 if (abi) {
6456 u64 mask = event->attr.sample_regs_user;
6457 perf_output_sample_regs(handle,
6458 data->regs_user.regs,
6459 mask);
6460 }
6461 }
6462
6463 if (sample_type & PERF_SAMPLE_STACK_USER) {
6464 perf_output_sample_ustack(handle,
6465 data->stack_user_size,
6466 data->regs_user.regs);
6467 }
6468
6469 if (sample_type & PERF_SAMPLE_WEIGHT)
6470 perf_output_put(handle, data->weight);
6471
6472 if (sample_type & PERF_SAMPLE_DATA_SRC)
6473 perf_output_put(handle, data->data_src.val);
6474
6475 if (sample_type & PERF_SAMPLE_TRANSACTION)
6476 perf_output_put(handle, data->txn);
6477
6478 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6479 u64 abi = data->regs_intr.abi;
6480 /*
6481 * If there are no regs to dump, notice it through
6482 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6483 */
6484 perf_output_put(handle, abi);
6485
6486 if (abi) {
6487 u64 mask = event->attr.sample_regs_intr;
6488
6489 perf_output_sample_regs(handle,
6490 data->regs_intr.regs,
6491 mask);
6492 }
6493 }
6494
6495 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6496 perf_output_put(handle, data->phys_addr);
6497
6498 if (!event->attr.watermark) {
6499 int wakeup_events = event->attr.wakeup_events;
6500
6501 if (wakeup_events) {
6502 struct ring_buffer *rb = handle->rb;
6503 int events = local_inc_return(&rb->events);
6504
6505 if (events >= wakeup_events) {
6506 local_sub(wakeup_events, &rb->events);
6507 local_inc(&rb->wakeup);
6508 }
6509 }
6510 }
6511}
6512
6513static u64 perf_virt_to_phys(u64 virt)
6514{
6515 u64 phys_addr = 0;
6516 struct page *p = NULL;
6517
6518 if (!virt)
6519 return 0;
6520
6521 if (virt >= TASK_SIZE) {
6522 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6523 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6524 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6525 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6526 } else {
6527 /*
6528 * Walking the pages tables for user address.
6529 * Interrupts are disabled, so it prevents any tear down
6530 * of the page tables.
6531 * Try IRQ-safe __get_user_pages_fast first.
6532 * If failed, leave phys_addr as 0.
6533 */
6534 if ((current->mm != NULL) &&
6535 (__get_user_pages_fast(virt, 1, 0, &p) == 1))
6536 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6537
6538 if (p)
6539 put_page(p);
6540 }
6541
6542 return phys_addr;
6543}
6544
6545static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6546
6547struct perf_callchain_entry *
6548perf_callchain(struct perf_event *event, struct pt_regs *regs)
6549{
6550 bool kernel = !event->attr.exclude_callchain_kernel;
6551 bool user = !event->attr.exclude_callchain_user;
6552 /* Disallow cross-task user callchains. */
6553 bool crosstask = event->ctx->task && event->ctx->task != current;
6554 const u32 max_stack = event->attr.sample_max_stack;
6555 struct perf_callchain_entry *callchain;
6556
6557 if (!kernel && !user)
6558 return &__empty_callchain;
6559
6560 callchain = get_perf_callchain(regs, 0, kernel, user,
6561 max_stack, crosstask, true);
6562 return callchain ?: &__empty_callchain;
6563}
6564
6565void perf_prepare_sample(struct perf_event_header *header,
6566 struct perf_sample_data *data,
6567 struct perf_event *event,
6568 struct pt_regs *regs)
6569{
6570 u64 sample_type = event->attr.sample_type;
6571
6572 header->type = PERF_RECORD_SAMPLE;
6573 header->size = sizeof(*header) + event->header_size;
6574
6575 header->misc = 0;
6576 header->misc |= perf_misc_flags(regs);
6577
6578 __perf_event_header__init_id(header, data, event);
6579
6580 if (sample_type & PERF_SAMPLE_IP)
6581 data->ip = perf_instruction_pointer(regs);
6582
6583 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6584 int size = 1;
6585
6586 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6587 data->callchain = perf_callchain(event, regs);
6588
6589 size += data->callchain->nr;
6590
6591 header->size += size * sizeof(u64);
6592 }
6593
6594 if (sample_type & PERF_SAMPLE_RAW) {
6595 struct perf_raw_record *raw = data->raw;
6596 int size;
6597
6598 if (raw) {
6599 struct perf_raw_frag *frag = &raw->frag;
6600 u32 sum = 0;
6601
6602 do {
6603 sum += frag->size;
6604 if (perf_raw_frag_last(frag))
6605 break;
6606 frag = frag->next;
6607 } while (1);
6608
6609 size = round_up(sum + sizeof(u32), sizeof(u64));
6610 raw->size = size - sizeof(u32);
6611 frag->pad = raw->size - sum;
6612 } else {
6613 size = sizeof(u64);
6614 }
6615
6616 header->size += size;
6617 }
6618
6619 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6620 int size = sizeof(u64); /* nr */
6621 if (data->br_stack) {
6622 size += data->br_stack->nr
6623 * sizeof(struct perf_branch_entry);
6624 }
6625 header->size += size;
6626 }
6627
6628 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6629 perf_sample_regs_user(&data->regs_user, regs,
6630 &data->regs_user_copy);
6631
6632 if (sample_type & PERF_SAMPLE_REGS_USER) {
6633 /* regs dump ABI info */
6634 int size = sizeof(u64);
6635
6636 if (data->regs_user.regs) {
6637 u64 mask = event->attr.sample_regs_user;
6638 size += hweight64(mask) * sizeof(u64);
6639 }
6640
6641 header->size += size;
6642 }
6643
6644 if (sample_type & PERF_SAMPLE_STACK_USER) {
6645 /*
6646 * Either we need PERF_SAMPLE_STACK_USER bit to be always
6647 * processed as the last one or have additional check added
6648 * in case new sample type is added, because we could eat
6649 * up the rest of the sample size.
6650 */
6651 u16 stack_size = event->attr.sample_stack_user;
6652 u16 size = sizeof(u64);
6653
6654 stack_size = perf_sample_ustack_size(stack_size, header->size,
6655 data->regs_user.regs);
6656
6657 /*
6658 * If there is something to dump, add space for the dump
6659 * itself and for the field that tells the dynamic size,
6660 * which is how many have been actually dumped.
6661 */
6662 if (stack_size)
6663 size += sizeof(u64) + stack_size;
6664
6665 data->stack_user_size = stack_size;
6666 header->size += size;
6667 }
6668
6669 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6670 /* regs dump ABI info */
6671 int size = sizeof(u64);
6672
6673 perf_sample_regs_intr(&data->regs_intr, regs);
6674
6675 if (data->regs_intr.regs) {
6676 u64 mask = event->attr.sample_regs_intr;
6677
6678 size += hweight64(mask) * sizeof(u64);
6679 }
6680
6681 header->size += size;
6682 }
6683
6684 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6685 data->phys_addr = perf_virt_to_phys(data->addr);
6686}
6687
6688static __always_inline int
6689__perf_event_output(struct perf_event *event,
6690 struct perf_sample_data *data,
6691 struct pt_regs *regs,
6692 int (*output_begin)(struct perf_output_handle *,
6693 struct perf_event *,
6694 unsigned int))
6695{
6696 struct perf_output_handle handle;
6697 struct perf_event_header header;
6698 int err;
6699
6700 /* protect the callchain buffers */
6701 rcu_read_lock();
6702
6703 perf_prepare_sample(&header, data, event, regs);
6704
6705 err = output_begin(&handle, event, header.size);
6706 if (err)
6707 goto exit;
6708
6709 perf_output_sample(&handle, &header, data, event);
6710
6711 perf_output_end(&handle);
6712
6713exit:
6714 rcu_read_unlock();
6715 return err;
6716}
6717
6718void
6719perf_event_output_forward(struct perf_event *event,
6720 struct perf_sample_data *data,
6721 struct pt_regs *regs)
6722{
6723 __perf_event_output(event, data, regs, perf_output_begin_forward);
6724}
6725
6726void
6727perf_event_output_backward(struct perf_event *event,
6728 struct perf_sample_data *data,
6729 struct pt_regs *regs)
6730{
6731 __perf_event_output(event, data, regs, perf_output_begin_backward);
6732}
6733
6734int
6735perf_event_output(struct perf_event *event,
6736 struct perf_sample_data *data,
6737 struct pt_regs *regs)
6738{
6739 return __perf_event_output(event, data, regs, perf_output_begin);
6740}
6741
6742/*
6743 * read event_id
6744 */
6745
6746struct perf_read_event {
6747 struct perf_event_header header;
6748
6749 u32 pid;
6750 u32 tid;
6751};
6752
6753static void
6754perf_event_read_event(struct perf_event *event,
6755 struct task_struct *task)
6756{
6757 struct perf_output_handle handle;
6758 struct perf_sample_data sample;
6759 struct perf_read_event read_event = {
6760 .header = {
6761 .type = PERF_RECORD_READ,
6762 .misc = 0,
6763 .size = sizeof(read_event) + event->read_size,
6764 },
6765 .pid = perf_event_pid(event, task),
6766 .tid = perf_event_tid(event, task),
6767 };
6768 int ret;
6769
6770 perf_event_header__init_id(&read_event.header, &sample, event);
6771 ret = perf_output_begin(&handle, event, read_event.header.size);
6772 if (ret)
6773 return;
6774
6775 perf_output_put(&handle, read_event);
6776 perf_output_read(&handle, event);
6777 perf_event__output_id_sample(event, &handle, &sample);
6778
6779 perf_output_end(&handle);
6780}
6781
6782typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6783
6784static void
6785perf_iterate_ctx(struct perf_event_context *ctx,
6786 perf_iterate_f output,
6787 void *data, bool all)
6788{
6789 struct perf_event *event;
6790
6791 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6792 if (!all) {
6793 if (event->state < PERF_EVENT_STATE_INACTIVE)
6794 continue;
6795 if (!event_filter_match(event))
6796 continue;
6797 }
6798
6799 output(event, data);
6800 }
6801}
6802
6803static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6804{
6805 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6806 struct perf_event *event;
6807
6808 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6809 /*
6810 * Skip events that are not fully formed yet; ensure that
6811 * if we observe event->ctx, both event and ctx will be
6812 * complete enough. See perf_install_in_context().
6813 */
6814 if (!smp_load_acquire(&event->ctx))
6815 continue;
6816
6817 if (event->state < PERF_EVENT_STATE_INACTIVE)
6818 continue;
6819 if (!event_filter_match(event))
6820 continue;
6821 output(event, data);
6822 }
6823}
6824
6825/*
6826 * Iterate all events that need to receive side-band events.
6827 *
6828 * For new callers; ensure that account_pmu_sb_event() includes
6829 * your event, otherwise it might not get delivered.
6830 */
6831static void
6832perf_iterate_sb(perf_iterate_f output, void *data,
6833 struct perf_event_context *task_ctx)
6834{
6835 struct perf_event_context *ctx;
6836 int ctxn;
6837
6838 rcu_read_lock();
6839 preempt_disable();
6840
6841 /*
6842 * If we have task_ctx != NULL we only notify the task context itself.
6843 * The task_ctx is set only for EXIT events before releasing task
6844 * context.
6845 */
6846 if (task_ctx) {
6847 perf_iterate_ctx(task_ctx, output, data, false);
6848 goto done;
6849 }
6850
6851 perf_iterate_sb_cpu(output, data);
6852
6853 for_each_task_context_nr(ctxn) {
6854 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6855 if (ctx)
6856 perf_iterate_ctx(ctx, output, data, false);
6857 }
6858done:
6859 preempt_enable();
6860 rcu_read_unlock();
6861}
6862
6863/*
6864 * Clear all file-based filters at exec, they'll have to be
6865 * re-instated when/if these objects are mmapped again.
6866 */
6867static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6868{
6869 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6870 struct perf_addr_filter *filter;
6871 unsigned int restart = 0, count = 0;
6872 unsigned long flags;
6873
6874 if (!has_addr_filter(event))
6875 return;
6876
6877 raw_spin_lock_irqsave(&ifh->lock, flags);
6878 list_for_each_entry(filter, &ifh->list, entry) {
6879 if (filter->path.dentry) {
6880 event->addr_filter_ranges[count].start = 0;
6881 event->addr_filter_ranges[count].size = 0;
6882 restart++;
6883 }
6884
6885 count++;
6886 }
6887
6888 if (restart)
6889 event->addr_filters_gen++;
6890 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6891
6892 if (restart)
6893 perf_event_stop(event, 1);
6894}
6895
6896void perf_event_exec(void)
6897{
6898 struct perf_event_context *ctx;
6899 int ctxn;
6900
6901 rcu_read_lock();
6902 for_each_task_context_nr(ctxn) {
6903 ctx = current->perf_event_ctxp[ctxn];
6904 if (!ctx)
6905 continue;
6906
6907 perf_event_enable_on_exec(ctxn);
6908
6909 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6910 true);
6911 }
6912 rcu_read_unlock();
6913}
6914
6915struct remote_output {
6916 struct ring_buffer *rb;
6917 int err;
6918};
6919
6920static void __perf_event_output_stop(struct perf_event *event, void *data)
6921{
6922 struct perf_event *parent = event->parent;
6923 struct remote_output *ro = data;
6924 struct ring_buffer *rb = ro->rb;
6925 struct stop_event_data sd = {
6926 .event = event,
6927 };
6928
6929 if (!has_aux(event))
6930 return;
6931
6932 if (!parent)
6933 parent = event;
6934
6935 /*
6936 * In case of inheritance, it will be the parent that links to the
6937 * ring-buffer, but it will be the child that's actually using it.
6938 *
6939 * We are using event::rb to determine if the event should be stopped,
6940 * however this may race with ring_buffer_attach() (through set_output),
6941 * which will make us skip the event that actually needs to be stopped.
6942 * So ring_buffer_attach() has to stop an aux event before re-assigning
6943 * its rb pointer.
6944 */
6945 if (rcu_dereference(parent->rb) == rb)
6946 ro->err = __perf_event_stop(&sd);
6947}
6948
6949static int __perf_pmu_output_stop(void *info)
6950{
6951 struct perf_event *event = info;
6952 struct pmu *pmu = event->ctx->pmu;
6953 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6954 struct remote_output ro = {
6955 .rb = event->rb,
6956 };
6957
6958 rcu_read_lock();
6959 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6960 if (cpuctx->task_ctx)
6961 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6962 &ro, false);
6963 rcu_read_unlock();
6964
6965 return ro.err;
6966}
6967
6968static void perf_pmu_output_stop(struct perf_event *event)
6969{
6970 struct perf_event *iter;
6971 int err, cpu;
6972
6973restart:
6974 rcu_read_lock();
6975 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6976 /*
6977 * For per-CPU events, we need to make sure that neither they
6978 * nor their children are running; for cpu==-1 events it's
6979 * sufficient to stop the event itself if it's active, since
6980 * it can't have children.
6981 */
6982 cpu = iter->cpu;
6983 if (cpu == -1)
6984 cpu = READ_ONCE(iter->oncpu);
6985
6986 if (cpu == -1)
6987 continue;
6988
6989 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6990 if (err == -EAGAIN) {
6991 rcu_read_unlock();
6992 goto restart;
6993 }
6994 }
6995 rcu_read_unlock();
6996}
6997
6998/*
6999 * task tracking -- fork/exit
7000 *
7001 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
7002 */
7003
7004struct perf_task_event {
7005 struct task_struct *task;
7006 struct perf_event_context *task_ctx;
7007
7008 struct {
7009 struct perf_event_header header;
7010
7011 u32 pid;
7012 u32 ppid;
7013 u32 tid;
7014 u32 ptid;
7015 u64 time;
7016 } event_id;
7017};
7018
7019static int perf_event_task_match(struct perf_event *event)
7020{
7021 return event->attr.comm || event->attr.mmap ||
7022 event->attr.mmap2 || event->attr.mmap_data ||
7023 event->attr.task;
7024}
7025
7026static void perf_event_task_output(struct perf_event *event,
7027 void *data)
7028{
7029 struct perf_task_event *task_event = data;
7030 struct perf_output_handle handle;
7031 struct perf_sample_data sample;
7032 struct task_struct *task = task_event->task;
7033 int ret, size = task_event->event_id.header.size;
7034
7035 if (!perf_event_task_match(event))
7036 return;
7037
7038 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
7039
7040 ret = perf_output_begin(&handle, event,
7041 task_event->event_id.header.size);
7042 if (ret)
7043 goto out;
7044
7045 task_event->event_id.pid = perf_event_pid(event, task);
7046 task_event->event_id.ppid = perf_event_pid(event, current);
7047
7048 task_event->event_id.tid = perf_event_tid(event, task);
7049 task_event->event_id.ptid = perf_event_tid(event, current);
7050
7051 task_event->event_id.time = perf_event_clock(event);
7052
7053 perf_output_put(&handle, task_event->event_id);
7054
7055 perf_event__output_id_sample(event, &handle, &sample);
7056
7057 perf_output_end(&handle);
7058out:
7059 task_event->event_id.header.size = size;
7060}
7061
7062static void perf_event_task(struct task_struct *task,
7063 struct perf_event_context *task_ctx,
7064 int new)
7065{
7066 struct perf_task_event task_event;
7067
7068 if (!atomic_read(&nr_comm_events) &&
7069 !atomic_read(&nr_mmap_events) &&
7070 !atomic_read(&nr_task_events))
7071 return;
7072
7073 task_event = (struct perf_task_event){
7074 .task = task,
7075 .task_ctx = task_ctx,
7076 .event_id = {
7077 .header = {
7078 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7079 .misc = 0,
7080 .size = sizeof(task_event.event_id),
7081 },
7082 /* .pid */
7083 /* .ppid */
7084 /* .tid */
7085 /* .ptid */
7086 /* .time */
7087 },
7088 };
7089
7090 perf_iterate_sb(perf_event_task_output,
7091 &task_event,
7092 task_ctx);
7093}
7094
7095void perf_event_fork(struct task_struct *task)
7096{
7097 perf_event_task(task, NULL, 1);
7098 perf_event_namespaces(task);
7099}
7100
7101/*
7102 * comm tracking
7103 */
7104
7105struct perf_comm_event {
7106 struct task_struct *task;
7107 char *comm;
7108 int comm_size;
7109
7110 struct {
7111 struct perf_event_header header;
7112
7113 u32 pid;
7114 u32 tid;
7115 } event_id;
7116};
7117
7118static int perf_event_comm_match(struct perf_event *event)
7119{
7120 return event->attr.comm;
7121}
7122
7123static void perf_event_comm_output(struct perf_event *event,
7124 void *data)
7125{
7126 struct perf_comm_event *comm_event = data;
7127 struct perf_output_handle handle;
7128 struct perf_sample_data sample;
7129 int size = comm_event->event_id.header.size;
7130 int ret;
7131
7132 if (!perf_event_comm_match(event))
7133 return;
7134
7135 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7136 ret = perf_output_begin(&handle, event,
7137 comm_event->event_id.header.size);
7138
7139 if (ret)
7140 goto out;
7141
7142 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7143 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7144
7145 perf_output_put(&handle, comm_event->event_id);
7146 __output_copy(&handle, comm_event->comm,
7147 comm_event->comm_size);
7148
7149 perf_event__output_id_sample(event, &handle, &sample);
7150
7151 perf_output_end(&handle);
7152out:
7153 comm_event->event_id.header.size = size;
7154}
7155
7156static void perf_event_comm_event(struct perf_comm_event *comm_event)
7157{
7158 char comm[TASK_COMM_LEN];
7159 unsigned int size;
7160
7161 memset(comm, 0, sizeof(comm));
7162 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7163 size = ALIGN(strlen(comm)+1, sizeof(u64));
7164
7165 comm_event->comm = comm;
7166 comm_event->comm_size = size;
7167
7168 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7169
7170 perf_iterate_sb(perf_event_comm_output,
7171 comm_event,
7172 NULL);
7173}
7174
7175void perf_event_comm(struct task_struct *task, bool exec)
7176{
7177 struct perf_comm_event comm_event;
7178
7179 if (!atomic_read(&nr_comm_events))
7180 return;
7181
7182 comm_event = (struct perf_comm_event){
7183 .task = task,
7184 /* .comm */
7185 /* .comm_size */
7186 .event_id = {
7187 .header = {
7188 .type = PERF_RECORD_COMM,
7189 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7190 /* .size */
7191 },
7192 /* .pid */
7193 /* .tid */
7194 },
7195 };
7196
7197 perf_event_comm_event(&comm_event);
7198}
7199
7200/*
7201 * namespaces tracking
7202 */
7203
7204struct perf_namespaces_event {
7205 struct task_struct *task;
7206
7207 struct {
7208 struct perf_event_header header;
7209
7210 u32 pid;
7211 u32 tid;
7212 u64 nr_namespaces;
7213 struct perf_ns_link_info link_info[NR_NAMESPACES];
7214 } event_id;
7215};
7216
7217static int perf_event_namespaces_match(struct perf_event *event)
7218{
7219 return event->attr.namespaces;
7220}
7221
7222static void perf_event_namespaces_output(struct perf_event *event,
7223 void *data)
7224{
7225 struct perf_namespaces_event *namespaces_event = data;
7226 struct perf_output_handle handle;
7227 struct perf_sample_data sample;
7228 u16 header_size = namespaces_event->event_id.header.size;
7229 int ret;
7230
7231 if (!perf_event_namespaces_match(event))
7232 return;
7233
7234 perf_event_header__init_id(&namespaces_event->event_id.header,
7235 &sample, event);
7236 ret = perf_output_begin(&handle, event,
7237 namespaces_event->event_id.header.size);
7238 if (ret)
7239 goto out;
7240
7241 namespaces_event->event_id.pid = perf_event_pid(event,
7242 namespaces_event->task);
7243 namespaces_event->event_id.tid = perf_event_tid(event,
7244 namespaces_event->task);
7245
7246 perf_output_put(&handle, namespaces_event->event_id);
7247
7248 perf_event__output_id_sample(event, &handle, &sample);
7249
7250 perf_output_end(&handle);
7251out:
7252 namespaces_event->event_id.header.size = header_size;
7253}
7254
7255static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7256 struct task_struct *task,
7257 const struct proc_ns_operations *ns_ops)
7258{
7259 struct path ns_path;
7260 struct inode *ns_inode;
7261 void *error;
7262
7263 error = ns_get_path(&ns_path, task, ns_ops);
7264 if (!error) {
7265 ns_inode = ns_path.dentry->d_inode;
7266 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7267 ns_link_info->ino = ns_inode->i_ino;
7268 path_put(&ns_path);
7269 }
7270}
7271
7272void perf_event_namespaces(struct task_struct *task)
7273{
7274 struct perf_namespaces_event namespaces_event;
7275 struct perf_ns_link_info *ns_link_info;
7276
7277 if (!atomic_read(&nr_namespaces_events))
7278 return;
7279
7280 namespaces_event = (struct perf_namespaces_event){
7281 .task = task,
7282 .event_id = {
7283 .header = {
7284 .type = PERF_RECORD_NAMESPACES,
7285 .misc = 0,
7286 .size = sizeof(namespaces_event.event_id),
7287 },
7288 /* .pid */
7289 /* .tid */
7290 .nr_namespaces = NR_NAMESPACES,
7291 /* .link_info[NR_NAMESPACES] */
7292 },
7293 };
7294
7295 ns_link_info = namespaces_event.event_id.link_info;
7296
7297 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7298 task, &mntns_operations);
7299
7300#ifdef CONFIG_USER_NS
7301 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7302 task, &userns_operations);
7303#endif
7304#ifdef CONFIG_NET_NS
7305 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7306 task, &netns_operations);
7307#endif
7308#ifdef CONFIG_UTS_NS
7309 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7310 task, &utsns_operations);
7311#endif
7312#ifdef CONFIG_IPC_NS
7313 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7314 task, &ipcns_operations);
7315#endif
7316#ifdef CONFIG_PID_NS
7317 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7318 task, &pidns_operations);
7319#endif
7320#ifdef CONFIG_CGROUPS
7321 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7322 task, &cgroupns_operations);
7323#endif
7324
7325 perf_iterate_sb(perf_event_namespaces_output,
7326 &namespaces_event,
7327 NULL);
7328}
7329
7330/*
7331 * mmap tracking
7332 */
7333
7334struct perf_mmap_event {
7335 struct vm_area_struct *vma;
7336
7337 const char *file_name;
7338 int file_size;
7339 int maj, min;
7340 u64 ino;
7341 u64 ino_generation;
7342 u32 prot, flags;
7343
7344 struct {
7345 struct perf_event_header header;
7346
7347 u32 pid;
7348 u32 tid;
7349 u64 start;
7350 u64 len;
7351 u64 pgoff;
7352 } event_id;
7353};
7354
7355static int perf_event_mmap_match(struct perf_event *event,
7356 void *data)
7357{
7358 struct perf_mmap_event *mmap_event = data;
7359 struct vm_area_struct *vma = mmap_event->vma;
7360 int executable = vma->vm_flags & VM_EXEC;
7361
7362 return (!executable && event->attr.mmap_data) ||
7363 (executable && (event->attr.mmap || event->attr.mmap2));
7364}
7365
7366static void perf_event_mmap_output(struct perf_event *event,
7367 void *data)
7368{
7369 struct perf_mmap_event *mmap_event = data;
7370 struct perf_output_handle handle;
7371 struct perf_sample_data sample;
7372 int size = mmap_event->event_id.header.size;
7373 u32 type = mmap_event->event_id.header.type;
7374 int ret;
7375
7376 if (!perf_event_mmap_match(event, data))
7377 return;
7378
7379 if (event->attr.mmap2) {
7380 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7381 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7382 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7383 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7384 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7385 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7386 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7387 }
7388
7389 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7390 ret = perf_output_begin(&handle, event,
7391 mmap_event->event_id.header.size);
7392 if (ret)
7393 goto out;
7394
7395 mmap_event->event_id.pid = perf_event_pid(event, current);
7396 mmap_event->event_id.tid = perf_event_tid(event, current);
7397
7398 perf_output_put(&handle, mmap_event->event_id);
7399
7400 if (event->attr.mmap2) {
7401 perf_output_put(&handle, mmap_event->maj);
7402 perf_output_put(&handle, mmap_event->min);
7403 perf_output_put(&handle, mmap_event->ino);
7404 perf_output_put(&handle, mmap_event->ino_generation);
7405 perf_output_put(&handle, mmap_event->prot);
7406 perf_output_put(&handle, mmap_event->flags);
7407 }
7408
7409 __output_copy(&handle, mmap_event->file_name,
7410 mmap_event->file_size);
7411
7412 perf_event__output_id_sample(event, &handle, &sample);
7413
7414 perf_output_end(&handle);
7415out:
7416 mmap_event->event_id.header.size = size;
7417 mmap_event->event_id.header.type = type;
7418}
7419
7420static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7421{
7422 struct vm_area_struct *vma = mmap_event->vma;
7423 struct file *file = vma->vm_file;
7424 int maj = 0, min = 0;
7425 u64 ino = 0, gen = 0;
7426 u32 prot = 0, flags = 0;
7427 unsigned int size;
7428 char tmp[16];
7429 char *buf = NULL;
7430 char *name;
7431
7432 if (vma->vm_flags & VM_READ)
7433 prot |= PROT_READ;
7434 if (vma->vm_flags & VM_WRITE)
7435 prot |= PROT_WRITE;
7436 if (vma->vm_flags & VM_EXEC)
7437 prot |= PROT_EXEC;
7438
7439 if (vma->vm_flags & VM_MAYSHARE)
7440 flags = MAP_SHARED;
7441 else
7442 flags = MAP_PRIVATE;
7443
7444 if (vma->vm_flags & VM_DENYWRITE)
7445 flags |= MAP_DENYWRITE;
7446 if (vma->vm_flags & VM_MAYEXEC)
7447 flags |= MAP_EXECUTABLE;
7448 if (vma->vm_flags & VM_LOCKED)
7449 flags |= MAP_LOCKED;
7450 if (vma->vm_flags & VM_HUGETLB)
7451 flags |= MAP_HUGETLB;
7452
7453 if (file) {
7454 struct inode *inode;
7455 dev_t dev;
7456
7457 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7458 if (!buf) {
7459 name = "//enomem";
7460 goto cpy_name;
7461 }
7462 /*
7463 * d_path() works from the end of the rb backwards, so we
7464 * need to add enough zero bytes after the string to handle
7465 * the 64bit alignment we do later.
7466 */
7467 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7468 if (IS_ERR(name)) {
7469 name = "//toolong";
7470 goto cpy_name;
7471 }
7472 inode = file_inode(vma->vm_file);
7473 dev = inode->i_sb->s_dev;
7474 ino = inode->i_ino;
7475 gen = inode->i_generation;
7476 maj = MAJOR(dev);
7477 min = MINOR(dev);
7478
7479 goto got_name;
7480 } else {
7481 if (vma->vm_ops && vma->vm_ops->name) {
7482 name = (char *) vma->vm_ops->name(vma);
7483 if (name)
7484 goto cpy_name;
7485 }
7486
7487 name = (char *)arch_vma_name(vma);
7488 if (name)
7489 goto cpy_name;
7490
7491 if (vma->vm_start <= vma->vm_mm->start_brk &&
7492 vma->vm_end >= vma->vm_mm->brk) {
7493 name = "[heap]";
7494 goto cpy_name;
7495 }
7496 if (vma->vm_start <= vma->vm_mm->start_stack &&
7497 vma->vm_end >= vma->vm_mm->start_stack) {
7498 name = "[stack]";
7499 goto cpy_name;
7500 }
7501
7502 name = "//anon";
7503 goto cpy_name;
7504 }
7505
7506cpy_name:
7507 strlcpy(tmp, name, sizeof(tmp));
7508 name = tmp;
7509got_name:
7510 /*
7511 * Since our buffer works in 8 byte units we need to align our string
7512 * size to a multiple of 8. However, we must guarantee the tail end is
7513 * zero'd out to avoid leaking random bits to userspace.
7514 */
7515 size = strlen(name)+1;
7516 while (!IS_ALIGNED(size, sizeof(u64)))
7517 name[size++] = '\0';
7518
7519 mmap_event->file_name = name;
7520 mmap_event->file_size = size;
7521 mmap_event->maj = maj;
7522 mmap_event->min = min;
7523 mmap_event->ino = ino;
7524 mmap_event->ino_generation = gen;
7525 mmap_event->prot = prot;
7526 mmap_event->flags = flags;
7527
7528 if (!(vma->vm_flags & VM_EXEC))
7529 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7530
7531 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7532
7533 perf_iterate_sb(perf_event_mmap_output,
7534 mmap_event,
7535 NULL);
7536
7537 kfree(buf);
7538}
7539
7540/*
7541 * Check whether inode and address range match filter criteria.
7542 */
7543static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7544 struct file *file, unsigned long offset,
7545 unsigned long size)
7546{
7547 /* d_inode(NULL) won't be equal to any mapped user-space file */
7548 if (!filter->path.dentry)
7549 return false;
7550
7551 if (d_inode(filter->path.dentry) != file_inode(file))
7552 return false;
7553
7554 if (filter->offset > offset + size)
7555 return false;
7556
7557 if (filter->offset + filter->size < offset)
7558 return false;
7559
7560 return true;
7561}
7562
7563static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
7564 struct vm_area_struct *vma,
7565 struct perf_addr_filter_range *fr)
7566{
7567 unsigned long vma_size = vma->vm_end - vma->vm_start;
7568 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7569 struct file *file = vma->vm_file;
7570
7571 if (!perf_addr_filter_match(filter, file, off, vma_size))
7572 return false;
7573
7574 if (filter->offset < off) {
7575 fr->start = vma->vm_start;
7576 fr->size = min(vma_size, filter->size - (off - filter->offset));
7577 } else {
7578 fr->start = vma->vm_start + filter->offset - off;
7579 fr->size = min(vma->vm_end - fr->start, filter->size);
7580 }
7581
7582 return true;
7583}
7584
7585static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7586{
7587 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7588 struct vm_area_struct *vma = data;
7589 struct perf_addr_filter *filter;
7590 unsigned int restart = 0, count = 0;
7591 unsigned long flags;
7592
7593 if (!has_addr_filter(event))
7594 return;
7595
7596 if (!vma->vm_file)
7597 return;
7598
7599 raw_spin_lock_irqsave(&ifh->lock, flags);
7600 list_for_each_entry(filter, &ifh->list, entry) {
7601 if (perf_addr_filter_vma_adjust(filter, vma,
7602 &event->addr_filter_ranges[count]))
7603 restart++;
7604
7605 count++;
7606 }
7607
7608 if (restart)
7609 event->addr_filters_gen++;
7610 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7611
7612 if (restart)
7613 perf_event_stop(event, 1);
7614}
7615
7616/*
7617 * Adjust all task's events' filters to the new vma
7618 */
7619static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7620{
7621 struct perf_event_context *ctx;
7622 int ctxn;
7623
7624 /*
7625 * Data tracing isn't supported yet and as such there is no need
7626 * to keep track of anything that isn't related to executable code:
7627 */
7628 if (!(vma->vm_flags & VM_EXEC))
7629 return;
7630
7631 rcu_read_lock();
7632 for_each_task_context_nr(ctxn) {
7633 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7634 if (!ctx)
7635 continue;
7636
7637 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7638 }
7639 rcu_read_unlock();
7640}
7641
7642void perf_event_mmap(struct vm_area_struct *vma)
7643{
7644 struct perf_mmap_event mmap_event;
7645
7646 if (!atomic_read(&nr_mmap_events))
7647 return;
7648
7649 mmap_event = (struct perf_mmap_event){
7650 .vma = vma,
7651 /* .file_name */
7652 /* .file_size */
7653 .event_id = {
7654 .header = {
7655 .type = PERF_RECORD_MMAP,
7656 .misc = PERF_RECORD_MISC_USER,
7657 /* .size */
7658 },
7659 /* .pid */
7660 /* .tid */
7661 .start = vma->vm_start,
7662 .len = vma->vm_end - vma->vm_start,
7663 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7664 },
7665 /* .maj (attr_mmap2 only) */
7666 /* .min (attr_mmap2 only) */
7667 /* .ino (attr_mmap2 only) */
7668 /* .ino_generation (attr_mmap2 only) */
7669 /* .prot (attr_mmap2 only) */
7670 /* .flags (attr_mmap2 only) */
7671 };
7672
7673 perf_addr_filters_adjust(vma);
7674 perf_event_mmap_event(&mmap_event);
7675}
7676
7677void perf_event_aux_event(struct perf_event *event, unsigned long head,
7678 unsigned long size, u64 flags)
7679{
7680 struct perf_output_handle handle;
7681 struct perf_sample_data sample;
7682 struct perf_aux_event {
7683 struct perf_event_header header;
7684 u64 offset;
7685 u64 size;
7686 u64 flags;
7687 } rec = {
7688 .header = {
7689 .type = PERF_RECORD_AUX,
7690 .misc = 0,
7691 .size = sizeof(rec),
7692 },
7693 .offset = head,
7694 .size = size,
7695 .flags = flags,
7696 };
7697 int ret;
7698
7699 perf_event_header__init_id(&rec.header, &sample, event);
7700 ret = perf_output_begin(&handle, event, rec.header.size);
7701
7702 if (ret)
7703 return;
7704
7705 perf_output_put(&handle, rec);
7706 perf_event__output_id_sample(event, &handle, &sample);
7707
7708 perf_output_end(&handle);
7709}
7710
7711/*
7712 * Lost/dropped samples logging
7713 */
7714void perf_log_lost_samples(struct perf_event *event, u64 lost)
7715{
7716 struct perf_output_handle handle;
7717 struct perf_sample_data sample;
7718 int ret;
7719
7720 struct {
7721 struct perf_event_header header;
7722 u64 lost;
7723 } lost_samples_event = {
7724 .header = {
7725 .type = PERF_RECORD_LOST_SAMPLES,
7726 .misc = 0,
7727 .size = sizeof(lost_samples_event),
7728 },
7729 .lost = lost,
7730 };
7731
7732 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7733
7734 ret = perf_output_begin(&handle, event,
7735 lost_samples_event.header.size);
7736 if (ret)
7737 return;
7738
7739 perf_output_put(&handle, lost_samples_event);
7740 perf_event__output_id_sample(event, &handle, &sample);
7741 perf_output_end(&handle);
7742}
7743
7744/*
7745 * context_switch tracking
7746 */
7747
7748struct perf_switch_event {
7749 struct task_struct *task;
7750 struct task_struct *next_prev;
7751
7752 struct {
7753 struct perf_event_header header;
7754 u32 next_prev_pid;
7755 u32 next_prev_tid;
7756 } event_id;
7757};
7758
7759static int perf_event_switch_match(struct perf_event *event)
7760{
7761 return event->attr.context_switch;
7762}
7763
7764static void perf_event_switch_output(struct perf_event *event, void *data)
7765{
7766 struct perf_switch_event *se = data;
7767 struct perf_output_handle handle;
7768 struct perf_sample_data sample;
7769 int ret;
7770
7771 if (!perf_event_switch_match(event))
7772 return;
7773
7774 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7775 if (event->ctx->task) {
7776 se->event_id.header.type = PERF_RECORD_SWITCH;
7777 se->event_id.header.size = sizeof(se->event_id.header);
7778 } else {
7779 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7780 se->event_id.header.size = sizeof(se->event_id);
7781 se->event_id.next_prev_pid =
7782 perf_event_pid(event, se->next_prev);
7783 se->event_id.next_prev_tid =
7784 perf_event_tid(event, se->next_prev);
7785 }
7786
7787 perf_event_header__init_id(&se->event_id.header, &sample, event);
7788
7789 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7790 if (ret)
7791 return;
7792
7793 if (event->ctx->task)
7794 perf_output_put(&handle, se->event_id.header);
7795 else
7796 perf_output_put(&handle, se->event_id);
7797
7798 perf_event__output_id_sample(event, &handle, &sample);
7799
7800 perf_output_end(&handle);
7801}
7802
7803static void perf_event_switch(struct task_struct *task,
7804 struct task_struct *next_prev, bool sched_in)
7805{
7806 struct perf_switch_event switch_event;
7807
7808 /* N.B. caller checks nr_switch_events != 0 */
7809
7810 switch_event = (struct perf_switch_event){
7811 .task = task,
7812 .next_prev = next_prev,
7813 .event_id = {
7814 .header = {
7815 /* .type */
7816 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7817 /* .size */
7818 },
7819 /* .next_prev_pid */
7820 /* .next_prev_tid */
7821 },
7822 };
7823
7824 if (!sched_in && task->state == TASK_RUNNING)
7825 switch_event.event_id.header.misc |=
7826 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
7827
7828 perf_iterate_sb(perf_event_switch_output,
7829 &switch_event,
7830 NULL);
7831}
7832
7833/*
7834 * IRQ throttle logging
7835 */
7836
7837static void perf_log_throttle(struct perf_event *event, int enable)
7838{
7839 struct perf_output_handle handle;
7840 struct perf_sample_data sample;
7841 int ret;
7842
7843 struct {
7844 struct perf_event_header header;
7845 u64 time;
7846 u64 id;
7847 u64 stream_id;
7848 } throttle_event = {
7849 .header = {
7850 .type = PERF_RECORD_THROTTLE,
7851 .misc = 0,
7852 .size = sizeof(throttle_event),
7853 },
7854 .time = perf_event_clock(event),
7855 .id = primary_event_id(event),
7856 .stream_id = event->id,
7857 };
7858
7859 if (enable)
7860 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7861
7862 perf_event_header__init_id(&throttle_event.header, &sample, event);
7863
7864 ret = perf_output_begin(&handle, event,
7865 throttle_event.header.size);
7866 if (ret)
7867 return;
7868
7869 perf_output_put(&handle, throttle_event);
7870 perf_event__output_id_sample(event, &handle, &sample);
7871 perf_output_end(&handle);
7872}
7873
7874/*
7875 * ksymbol register/unregister tracking
7876 */
7877
7878struct perf_ksymbol_event {
7879 const char *name;
7880 int name_len;
7881 struct {
7882 struct perf_event_header header;
7883 u64 addr;
7884 u32 len;
7885 u16 ksym_type;
7886 u16 flags;
7887 } event_id;
7888};
7889
7890static int perf_event_ksymbol_match(struct perf_event *event)
7891{
7892 return event->attr.ksymbol;
7893}
7894
7895static void perf_event_ksymbol_output(struct perf_event *event, void *data)
7896{
7897 struct perf_ksymbol_event *ksymbol_event = data;
7898 struct perf_output_handle handle;
7899 struct perf_sample_data sample;
7900 int ret;
7901
7902 if (!perf_event_ksymbol_match(event))
7903 return;
7904
7905 perf_event_header__init_id(&ksymbol_event->event_id.header,
7906 &sample, event);
7907 ret = perf_output_begin(&handle, event,
7908 ksymbol_event->event_id.header.size);
7909 if (ret)
7910 return;
7911
7912 perf_output_put(&handle, ksymbol_event->event_id);
7913 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
7914 perf_event__output_id_sample(event, &handle, &sample);
7915
7916 perf_output_end(&handle);
7917}
7918
7919void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
7920 const char *sym)
7921{
7922 struct perf_ksymbol_event ksymbol_event;
7923 char name[KSYM_NAME_LEN];
7924 u16 flags = 0;
7925 int name_len;
7926
7927 if (!atomic_read(&nr_ksymbol_events))
7928 return;
7929
7930 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
7931 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
7932 goto err;
7933
7934 strlcpy(name, sym, KSYM_NAME_LEN);
7935 name_len = strlen(name) + 1;
7936 while (!IS_ALIGNED(name_len, sizeof(u64)))
7937 name[name_len++] = '\0';
7938 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
7939
7940 if (unregister)
7941 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
7942
7943 ksymbol_event = (struct perf_ksymbol_event){
7944 .name = name,
7945 .name_len = name_len,
7946 .event_id = {
7947 .header = {
7948 .type = PERF_RECORD_KSYMBOL,
7949 .size = sizeof(ksymbol_event.event_id) +
7950 name_len,
7951 },
7952 .addr = addr,
7953 .len = len,
7954 .ksym_type = ksym_type,
7955 .flags = flags,
7956 },
7957 };
7958
7959 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
7960 return;
7961err:
7962 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
7963}
7964
7965/*
7966 * bpf program load/unload tracking
7967 */
7968
7969struct perf_bpf_event {
7970 struct bpf_prog *prog;
7971 struct {
7972 struct perf_event_header header;
7973 u16 type;
7974 u16 flags;
7975 u32 id;
7976 u8 tag[BPF_TAG_SIZE];
7977 } event_id;
7978};
7979
7980static int perf_event_bpf_match(struct perf_event *event)
7981{
7982 return event->attr.bpf_event;
7983}
7984
7985static void perf_event_bpf_output(struct perf_event *event, void *data)
7986{
7987 struct perf_bpf_event *bpf_event = data;
7988 struct perf_output_handle handle;
7989 struct perf_sample_data sample;
7990 int ret;
7991
7992 if (!perf_event_bpf_match(event))
7993 return;
7994
7995 perf_event_header__init_id(&bpf_event->event_id.header,
7996 &sample, event);
7997 ret = perf_output_begin(&handle, event,
7998 bpf_event->event_id.header.size);
7999 if (ret)
8000 return;
8001
8002 perf_output_put(&handle, bpf_event->event_id);
8003 perf_event__output_id_sample(event, &handle, &sample);
8004
8005 perf_output_end(&handle);
8006}
8007
8008static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
8009 enum perf_bpf_event_type type)
8010{
8011 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
8012 char sym[KSYM_NAME_LEN];
8013 int i;
8014
8015 if (prog->aux->func_cnt == 0) {
8016 bpf_get_prog_name(prog, sym);
8017 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
8018 (u64)(unsigned long)prog->bpf_func,
8019 prog->jited_len, unregister, sym);
8020 } else {
8021 for (i = 0; i < prog->aux->func_cnt; i++) {
8022 struct bpf_prog *subprog = prog->aux->func[i];
8023
8024 bpf_get_prog_name(subprog, sym);
8025 perf_event_ksymbol(
8026 PERF_RECORD_KSYMBOL_TYPE_BPF,
8027 (u64)(unsigned long)subprog->bpf_func,
8028 subprog->jited_len, unregister, sym);
8029 }
8030 }
8031}
8032
8033void perf_event_bpf_event(struct bpf_prog *prog,
8034 enum perf_bpf_event_type type,
8035 u16 flags)
8036{
8037 struct perf_bpf_event bpf_event;
8038
8039 if (type <= PERF_BPF_EVENT_UNKNOWN ||
8040 type >= PERF_BPF_EVENT_MAX)
8041 return;
8042
8043 switch (type) {
8044 case PERF_BPF_EVENT_PROG_LOAD:
8045 case PERF_BPF_EVENT_PROG_UNLOAD:
8046 if (atomic_read(&nr_ksymbol_events))
8047 perf_event_bpf_emit_ksymbols(prog, type);
8048 break;
8049 default:
8050 break;
8051 }
8052
8053 if (!atomic_read(&nr_bpf_events))
8054 return;
8055
8056 bpf_event = (struct perf_bpf_event){
8057 .prog = prog,
8058 .event_id = {
8059 .header = {
8060 .type = PERF_RECORD_BPF_EVENT,
8061 .size = sizeof(bpf_event.event_id),
8062 },
8063 .type = type,
8064 .flags = flags,
8065 .id = prog->aux->id,
8066 },
8067 };
8068
8069 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
8070
8071 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
8072 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
8073}
8074
8075void perf_event_itrace_started(struct perf_event *event)
8076{
8077 event->attach_state |= PERF_ATTACH_ITRACE;
8078}
8079
8080static void perf_log_itrace_start(struct perf_event *event)
8081{
8082 struct perf_output_handle handle;
8083 struct perf_sample_data sample;
8084 struct perf_aux_event {
8085 struct perf_event_header header;
8086 u32 pid;
8087 u32 tid;
8088 } rec;
8089 int ret;
8090
8091 if (event->parent)
8092 event = event->parent;
8093
8094 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
8095 event->attach_state & PERF_ATTACH_ITRACE)
8096 return;
8097
8098 rec.header.type = PERF_RECORD_ITRACE_START;
8099 rec.header.misc = 0;
8100 rec.header.size = sizeof(rec);
8101 rec.pid = perf_event_pid(event, current);
8102 rec.tid = perf_event_tid(event, current);
8103
8104 perf_event_header__init_id(&rec.header, &sample, event);
8105 ret = perf_output_begin(&handle, event, rec.header.size);
8106
8107 if (ret)
8108 return;
8109
8110 perf_output_put(&handle, rec);
8111 perf_event__output_id_sample(event, &handle, &sample);
8112
8113 perf_output_end(&handle);
8114}
8115
8116static int
8117__perf_event_account_interrupt(struct perf_event *event, int throttle)
8118{
8119 struct hw_perf_event *hwc = &event->hw;
8120 int ret = 0;
8121 u64 seq;
8122
8123 seq = __this_cpu_read(perf_throttled_seq);
8124 if (seq != hwc->interrupts_seq) {
8125 hwc->interrupts_seq = seq;
8126 hwc->interrupts = 1;
8127 } else {
8128 hwc->interrupts++;
8129 if (unlikely(throttle
8130 && hwc->interrupts >= max_samples_per_tick)) {
8131 __this_cpu_inc(perf_throttled_count);
8132 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
8133 hwc->interrupts = MAX_INTERRUPTS;
8134 perf_log_throttle(event, 0);
8135 ret = 1;
8136 }
8137 }
8138
8139 if (event->attr.freq) {
8140 u64 now = perf_clock();
8141 s64 delta = now - hwc->freq_time_stamp;
8142
8143 hwc->freq_time_stamp = now;
8144
8145 if (delta > 0 && delta < 2*TICK_NSEC)
8146 perf_adjust_period(event, delta, hwc->last_period, true);
8147 }
8148
8149 return ret;
8150}
8151
8152int perf_event_account_interrupt(struct perf_event *event)
8153{
8154 return __perf_event_account_interrupt(event, 1);
8155}
8156
8157/*
8158 * Generic event overflow handling, sampling.
8159 */
8160
8161static int __perf_event_overflow(struct perf_event *event,
8162 int throttle, struct perf_sample_data *data,
8163 struct pt_regs *regs)
8164{
8165 int events = atomic_read(&event->event_limit);
8166 int ret = 0;
8167
8168 /*
8169 * Non-sampling counters might still use the PMI to fold short
8170 * hardware counters, ignore those.
8171 */
8172 if (unlikely(!is_sampling_event(event)))
8173 return 0;
8174
8175 ret = __perf_event_account_interrupt(event, throttle);
8176
8177 /*
8178 * XXX event_limit might not quite work as expected on inherited
8179 * events
8180 */
8181
8182 event->pending_kill = POLL_IN;
8183 if (events && atomic_dec_and_test(&event->event_limit)) {
8184 ret = 1;
8185 event->pending_kill = POLL_HUP;
8186
8187 perf_event_disable_inatomic(event);
8188 }
8189
8190 READ_ONCE(event->overflow_handler)(event, data, regs);
8191
8192 if (*perf_event_fasync(event) && event->pending_kill) {
8193 event->pending_wakeup = 1;
8194 irq_work_queue(&event->pending);
8195 }
8196
8197 return ret;
8198}
8199
8200int perf_event_overflow(struct perf_event *event,
8201 struct perf_sample_data *data,
8202 struct pt_regs *regs)
8203{
8204 return __perf_event_overflow(event, 1, data, regs);
8205}
8206
8207/*
8208 * Generic software event infrastructure
8209 */
8210
8211struct swevent_htable {
8212 struct swevent_hlist *swevent_hlist;
8213 struct mutex hlist_mutex;
8214 int hlist_refcount;
8215
8216 /* Recursion avoidance in each contexts */
8217 int recursion[PERF_NR_CONTEXTS];
8218};
8219
8220static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
8221
8222/*
8223 * We directly increment event->count and keep a second value in
8224 * event->hw.period_left to count intervals. This period event
8225 * is kept in the range [-sample_period, 0] so that we can use the
8226 * sign as trigger.
8227 */
8228
8229u64 perf_swevent_set_period(struct perf_event *event)
8230{
8231 struct hw_perf_event *hwc = &event->hw;
8232 u64 period = hwc->last_period;
8233 u64 nr, offset;
8234 s64 old, val;
8235
8236 hwc->last_period = hwc->sample_period;
8237
8238again:
8239 old = val = local64_read(&hwc->period_left);
8240 if (val < 0)
8241 return 0;
8242
8243 nr = div64_u64(period + val, period);
8244 offset = nr * period;
8245 val -= offset;
8246 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
8247 goto again;
8248
8249 return nr;
8250}
8251
8252static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
8253 struct perf_sample_data *data,
8254 struct pt_regs *regs)
8255{
8256 struct hw_perf_event *hwc = &event->hw;
8257 int throttle = 0;
8258
8259 if (!overflow)
8260 overflow = perf_swevent_set_period(event);
8261
8262 if (hwc->interrupts == MAX_INTERRUPTS)
8263 return;
8264
8265 for (; overflow; overflow--) {
8266 if (__perf_event_overflow(event, throttle,
8267 data, regs)) {
8268 /*
8269 * We inhibit the overflow from happening when
8270 * hwc->interrupts == MAX_INTERRUPTS.
8271 */
8272 break;
8273 }
8274 throttle = 1;
8275 }
8276}
8277
8278static void perf_swevent_event(struct perf_event *event, u64 nr,
8279 struct perf_sample_data *data,
8280 struct pt_regs *regs)
8281{
8282 struct hw_perf_event *hwc = &event->hw;
8283
8284 local64_add(nr, &event->count);
8285
8286 if (!regs)
8287 return;
8288
8289 if (!is_sampling_event(event))
8290 return;
8291
8292 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
8293 data->period = nr;
8294 return perf_swevent_overflow(event, 1, data, regs);
8295 } else
8296 data->period = event->hw.last_period;
8297
8298 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
8299 return perf_swevent_overflow(event, 1, data, regs);
8300
8301 if (local64_add_negative(nr, &hwc->period_left))
8302 return;
8303
8304 perf_swevent_overflow(event, 0, data, regs);
8305}
8306
8307static int perf_exclude_event(struct perf_event *event,
8308 struct pt_regs *regs)
8309{
8310 if (event->hw.state & PERF_HES_STOPPED)
8311 return 1;
8312
8313 if (regs) {
8314 if (event->attr.exclude_user && user_mode(regs))
8315 return 1;
8316
8317 if (event->attr.exclude_kernel && !user_mode(regs))
8318 return 1;
8319 }
8320
8321 return 0;
8322}
8323
8324static int perf_swevent_match(struct perf_event *event,
8325 enum perf_type_id type,
8326 u32 event_id,
8327 struct perf_sample_data *data,
8328 struct pt_regs *regs)
8329{
8330 if (event->attr.type != type)
8331 return 0;
8332
8333 if (event->attr.config != event_id)
8334 return 0;
8335
8336 if (perf_exclude_event(event, regs))
8337 return 0;
8338
8339 return 1;
8340}
8341
8342static inline u64 swevent_hash(u64 type, u32 event_id)
8343{
8344 u64 val = event_id | (type << 32);
8345
8346 return hash_64(val, SWEVENT_HLIST_BITS);
8347}
8348
8349static inline struct hlist_head *
8350__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
8351{
8352 u64 hash = swevent_hash(type, event_id);
8353
8354 return &hlist->heads[hash];
8355}
8356
8357/* For the read side: events when they trigger */
8358static inline struct hlist_head *
8359find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8360{
8361 struct swevent_hlist *hlist;
8362
8363 hlist = rcu_dereference(swhash->swevent_hlist);
8364 if (!hlist)
8365 return NULL;
8366
8367 return __find_swevent_head(hlist, type, event_id);
8368}
8369
8370/* For the event head insertion and removal in the hlist */
8371static inline struct hlist_head *
8372find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8373{
8374 struct swevent_hlist *hlist;
8375 u32 event_id = event->attr.config;
8376 u64 type = event->attr.type;
8377
8378 /*
8379 * Event scheduling is always serialized against hlist allocation
8380 * and release. Which makes the protected version suitable here.
8381 * The context lock guarantees that.
8382 */
8383 hlist = rcu_dereference_protected(swhash->swevent_hlist,
8384 lockdep_is_held(&event->ctx->lock));
8385 if (!hlist)
8386 return NULL;
8387
8388 return __find_swevent_head(hlist, type, event_id);
8389}
8390
8391static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8392 u64 nr,
8393 struct perf_sample_data *data,
8394 struct pt_regs *regs)
8395{
8396 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8397 struct perf_event *event;
8398 struct hlist_head *head;
8399
8400 rcu_read_lock();
8401 head = find_swevent_head_rcu(swhash, type, event_id);
8402 if (!head)
8403 goto end;
8404
8405 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8406 if (perf_swevent_match(event, type, event_id, data, regs))
8407 perf_swevent_event(event, nr, data, regs);
8408 }
8409end:
8410 rcu_read_unlock();
8411}
8412
8413DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8414
8415int perf_swevent_get_recursion_context(void)
8416{
8417 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8418
8419 return get_recursion_context(swhash->recursion);
8420}
8421EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8422
8423void perf_swevent_put_recursion_context(int rctx)
8424{
8425 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8426
8427 put_recursion_context(swhash->recursion, rctx);
8428}
8429
8430void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8431{
8432 struct perf_sample_data data;
8433
8434 if (WARN_ON_ONCE(!regs))
8435 return;
8436
8437 perf_sample_data_init(&data, addr, 0);
8438 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8439}
8440
8441void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8442{
8443 int rctx;
8444
8445 preempt_disable_notrace();
8446 rctx = perf_swevent_get_recursion_context();
8447 if (unlikely(rctx < 0))
8448 goto fail;
8449
8450 ___perf_sw_event(event_id, nr, regs, addr);
8451
8452 perf_swevent_put_recursion_context(rctx);
8453fail:
8454 preempt_enable_notrace();
8455}
8456
8457static void perf_swevent_read(struct perf_event *event)
8458{
8459}
8460
8461static int perf_swevent_add(struct perf_event *event, int flags)
8462{
8463 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8464 struct hw_perf_event *hwc = &event->hw;
8465 struct hlist_head *head;
8466
8467 if (is_sampling_event(event)) {
8468 hwc->last_period = hwc->sample_period;
8469 perf_swevent_set_period(event);
8470 }
8471
8472 hwc->state = !(flags & PERF_EF_START);
8473
8474 head = find_swevent_head(swhash, event);
8475 if (WARN_ON_ONCE(!head))
8476 return -EINVAL;
8477
8478 hlist_add_head_rcu(&event->hlist_entry, head);
8479 perf_event_update_userpage(event);
8480
8481 return 0;
8482}
8483
8484static void perf_swevent_del(struct perf_event *event, int flags)
8485{
8486 hlist_del_rcu(&event->hlist_entry);
8487}
8488
8489static void perf_swevent_start(struct perf_event *event, int flags)
8490{
8491 event->hw.state = 0;
8492}
8493
8494static void perf_swevent_stop(struct perf_event *event, int flags)
8495{
8496 event->hw.state = PERF_HES_STOPPED;
8497}
8498
8499/* Deref the hlist from the update side */
8500static inline struct swevent_hlist *
8501swevent_hlist_deref(struct swevent_htable *swhash)
8502{
8503 return rcu_dereference_protected(swhash->swevent_hlist,
8504 lockdep_is_held(&swhash->hlist_mutex));
8505}
8506
8507static void swevent_hlist_release(struct swevent_htable *swhash)
8508{
8509 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
8510
8511 if (!hlist)
8512 return;
8513
8514 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
8515 kfree_rcu(hlist, rcu_head);
8516}
8517
8518static void swevent_hlist_put_cpu(int cpu)
8519{
8520 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8521
8522 mutex_lock(&swhash->hlist_mutex);
8523
8524 if (!--swhash->hlist_refcount)
8525 swevent_hlist_release(swhash);
8526
8527 mutex_unlock(&swhash->hlist_mutex);
8528}
8529
8530static void swevent_hlist_put(void)
8531{
8532 int cpu;
8533
8534 for_each_possible_cpu(cpu)
8535 swevent_hlist_put_cpu(cpu);
8536}
8537
8538static int swevent_hlist_get_cpu(int cpu)
8539{
8540 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8541 int err = 0;
8542
8543 mutex_lock(&swhash->hlist_mutex);
8544 if (!swevent_hlist_deref(swhash) &&
8545 cpumask_test_cpu(cpu, perf_online_mask)) {
8546 struct swevent_hlist *hlist;
8547
8548 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
8549 if (!hlist) {
8550 err = -ENOMEM;
8551 goto exit;
8552 }
8553 rcu_assign_pointer(swhash->swevent_hlist, hlist);
8554 }
8555 swhash->hlist_refcount++;
8556exit:
8557 mutex_unlock(&swhash->hlist_mutex);
8558
8559 return err;
8560}
8561
8562static int swevent_hlist_get(void)
8563{
8564 int err, cpu, failed_cpu;
8565
8566 mutex_lock(&pmus_lock);
8567 for_each_possible_cpu(cpu) {
8568 err = swevent_hlist_get_cpu(cpu);
8569 if (err) {
8570 failed_cpu = cpu;
8571 goto fail;
8572 }
8573 }
8574 mutex_unlock(&pmus_lock);
8575 return 0;
8576fail:
8577 for_each_possible_cpu(cpu) {
8578 if (cpu == failed_cpu)
8579 break;
8580 swevent_hlist_put_cpu(cpu);
8581 }
8582 mutex_unlock(&pmus_lock);
8583 return err;
8584}
8585
8586struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
8587
8588static void sw_perf_event_destroy(struct perf_event *event)
8589{
8590 u64 event_id = event->attr.config;
8591
8592 WARN_ON(event->parent);
8593
8594 static_key_slow_dec(&perf_swevent_enabled[event_id]);
8595 swevent_hlist_put();
8596}
8597
8598static int perf_swevent_init(struct perf_event *event)
8599{
8600 u64 event_id = event->attr.config;
8601
8602 if (event->attr.type != PERF_TYPE_SOFTWARE)
8603 return -ENOENT;
8604
8605 /*
8606 * no branch sampling for software events
8607 */
8608 if (has_branch_stack(event))
8609 return -EOPNOTSUPP;
8610
8611 switch (event_id) {
8612 case PERF_COUNT_SW_CPU_CLOCK:
8613 case PERF_COUNT_SW_TASK_CLOCK:
8614 return -ENOENT;
8615
8616 default:
8617 break;
8618 }
8619
8620 if (event_id >= PERF_COUNT_SW_MAX)
8621 return -ENOENT;
8622
8623 if (!event->parent) {
8624 int err;
8625
8626 err = swevent_hlist_get();
8627 if (err)
8628 return err;
8629
8630 static_key_slow_inc(&perf_swevent_enabled[event_id]);
8631 event->destroy = sw_perf_event_destroy;
8632 }
8633
8634 return 0;
8635}
8636
8637static struct pmu perf_swevent = {
8638 .task_ctx_nr = perf_sw_context,
8639
8640 .capabilities = PERF_PMU_CAP_NO_NMI,
8641
8642 .event_init = perf_swevent_init,
8643 .add = perf_swevent_add,
8644 .del = perf_swevent_del,
8645 .start = perf_swevent_start,
8646 .stop = perf_swevent_stop,
8647 .read = perf_swevent_read,
8648};
8649
8650#ifdef CONFIG_EVENT_TRACING
8651
8652static int perf_tp_filter_match(struct perf_event *event,
8653 struct perf_sample_data *data)
8654{
8655 void *record = data->raw->frag.data;
8656
8657 /* only top level events have filters set */
8658 if (event->parent)
8659 event = event->parent;
8660
8661 if (likely(!event->filter) || filter_match_preds(event->filter, record))
8662 return 1;
8663 return 0;
8664}
8665
8666static int perf_tp_event_match(struct perf_event *event,
8667 struct perf_sample_data *data,
8668 struct pt_regs *regs)
8669{
8670 if (event->hw.state & PERF_HES_STOPPED)
8671 return 0;
8672 /*
8673 * If exclude_kernel, only trace user-space tracepoints (uprobes)
8674 */
8675 if (event->attr.exclude_kernel && !user_mode(regs))
8676 return 0;
8677
8678 if (!perf_tp_filter_match(event, data))
8679 return 0;
8680
8681 return 1;
8682}
8683
8684void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8685 struct trace_event_call *call, u64 count,
8686 struct pt_regs *regs, struct hlist_head *head,
8687 struct task_struct *task)
8688{
8689 if (bpf_prog_array_valid(call)) {
8690 *(struct pt_regs **)raw_data = regs;
8691 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
8692 perf_swevent_put_recursion_context(rctx);
8693 return;
8694 }
8695 }
8696 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8697 rctx, task);
8698}
8699EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8700
8701void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8702 struct pt_regs *regs, struct hlist_head *head, int rctx,
8703 struct task_struct *task)
8704{
8705 struct perf_sample_data data;
8706 struct perf_event *event;
8707
8708 struct perf_raw_record raw = {
8709 .frag = {
8710 .size = entry_size,
8711 .data = record,
8712 },
8713 };
8714
8715 perf_sample_data_init(&data, 0, 0);
8716 data.raw = &raw;
8717
8718 perf_trace_buf_update(record, event_type);
8719
8720 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8721 if (perf_tp_event_match(event, &data, regs))
8722 perf_swevent_event(event, count, &data, regs);
8723 }
8724
8725 /*
8726 * If we got specified a target task, also iterate its context and
8727 * deliver this event there too.
8728 */
8729 if (task && task != current) {
8730 struct perf_event_context *ctx;
8731 struct trace_entry *entry = record;
8732
8733 rcu_read_lock();
8734 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8735 if (!ctx)
8736 goto unlock;
8737
8738 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8739 if (event->cpu != smp_processor_id())
8740 continue;
8741 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8742 continue;
8743 if (event->attr.config != entry->type)
8744 continue;
8745 if (perf_tp_event_match(event, &data, regs))
8746 perf_swevent_event(event, count, &data, regs);
8747 }
8748unlock:
8749 rcu_read_unlock();
8750 }
8751
8752 perf_swevent_put_recursion_context(rctx);
8753}
8754EXPORT_SYMBOL_GPL(perf_tp_event);
8755
8756static void tp_perf_event_destroy(struct perf_event *event)
8757{
8758 perf_trace_destroy(event);
8759}
8760
8761static int perf_tp_event_init(struct perf_event *event)
8762{
8763 int err;
8764
8765 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8766 return -ENOENT;
8767
8768 /*
8769 * no branch sampling for tracepoint events
8770 */
8771 if (has_branch_stack(event))
8772 return -EOPNOTSUPP;
8773
8774 err = perf_trace_init(event);
8775 if (err)
8776 return err;
8777
8778 event->destroy = tp_perf_event_destroy;
8779
8780 return 0;
8781}
8782
8783static struct pmu perf_tracepoint = {
8784 .task_ctx_nr = perf_sw_context,
8785
8786 .event_init = perf_tp_event_init,
8787 .add = perf_trace_add,
8788 .del = perf_trace_del,
8789 .start = perf_swevent_start,
8790 .stop = perf_swevent_stop,
8791 .read = perf_swevent_read,
8792};
8793
8794#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
8795/*
8796 * Flags in config, used by dynamic PMU kprobe and uprobe
8797 * The flags should match following PMU_FORMAT_ATTR().
8798 *
8799 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
8800 * if not set, create kprobe/uprobe
8801 *
8802 * The following values specify a reference counter (or semaphore in the
8803 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
8804 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
8805 *
8806 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
8807 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
8808 */
8809enum perf_probe_config {
8810 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
8811 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
8812 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
8813};
8814
8815PMU_FORMAT_ATTR(retprobe, "config:0");
8816#endif
8817
8818#ifdef CONFIG_KPROBE_EVENTS
8819static struct attribute *kprobe_attrs[] = {
8820 &format_attr_retprobe.attr,
8821 NULL,
8822};
8823
8824static struct attribute_group kprobe_format_group = {
8825 .name = "format",
8826 .attrs = kprobe_attrs,
8827};
8828
8829static const struct attribute_group *kprobe_attr_groups[] = {
8830 &kprobe_format_group,
8831 NULL,
8832};
8833
8834static int perf_kprobe_event_init(struct perf_event *event);
8835static struct pmu perf_kprobe = {
8836 .task_ctx_nr = perf_sw_context,
8837 .event_init = perf_kprobe_event_init,
8838 .add = perf_trace_add,
8839 .del = perf_trace_del,
8840 .start = perf_swevent_start,
8841 .stop = perf_swevent_stop,
8842 .read = perf_swevent_read,
8843 .attr_groups = kprobe_attr_groups,
8844};
8845
8846static int perf_kprobe_event_init(struct perf_event *event)
8847{
8848 int err;
8849 bool is_retprobe;
8850
8851 if (event->attr.type != perf_kprobe.type)
8852 return -ENOENT;
8853
8854 if (!capable(CAP_SYS_ADMIN))
8855 return -EACCES;
8856
8857 /*
8858 * no branch sampling for probe events
8859 */
8860 if (has_branch_stack(event))
8861 return -EOPNOTSUPP;
8862
8863 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8864 err = perf_kprobe_init(event, is_retprobe);
8865 if (err)
8866 return err;
8867
8868 event->destroy = perf_kprobe_destroy;
8869
8870 return 0;
8871}
8872#endif /* CONFIG_KPROBE_EVENTS */
8873
8874#ifdef CONFIG_UPROBE_EVENTS
8875PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
8876
8877static struct attribute *uprobe_attrs[] = {
8878 &format_attr_retprobe.attr,
8879 &format_attr_ref_ctr_offset.attr,
8880 NULL,
8881};
8882
8883static struct attribute_group uprobe_format_group = {
8884 .name = "format",
8885 .attrs = uprobe_attrs,
8886};
8887
8888static const struct attribute_group *uprobe_attr_groups[] = {
8889 &uprobe_format_group,
8890 NULL,
8891};
8892
8893static int perf_uprobe_event_init(struct perf_event *event);
8894static struct pmu perf_uprobe = {
8895 .task_ctx_nr = perf_sw_context,
8896 .event_init = perf_uprobe_event_init,
8897 .add = perf_trace_add,
8898 .del = perf_trace_del,
8899 .start = perf_swevent_start,
8900 .stop = perf_swevent_stop,
8901 .read = perf_swevent_read,
8902 .attr_groups = uprobe_attr_groups,
8903};
8904
8905static int perf_uprobe_event_init(struct perf_event *event)
8906{
8907 int err;
8908 unsigned long ref_ctr_offset;
8909 bool is_retprobe;
8910
8911 if (event->attr.type != perf_uprobe.type)
8912 return -ENOENT;
8913
8914 if (!capable(CAP_SYS_ADMIN))
8915 return -EACCES;
8916
8917 /*
8918 * no branch sampling for probe events
8919 */
8920 if (has_branch_stack(event))
8921 return -EOPNOTSUPP;
8922
8923 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8924 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
8925 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
8926 if (err)
8927 return err;
8928
8929 event->destroy = perf_uprobe_destroy;
8930
8931 return 0;
8932}
8933#endif /* CONFIG_UPROBE_EVENTS */
8934
8935static inline void perf_tp_register(void)
8936{
8937 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8938#ifdef CONFIG_KPROBE_EVENTS
8939 perf_pmu_register(&perf_kprobe, "kprobe", -1);
8940#endif
8941#ifdef CONFIG_UPROBE_EVENTS
8942 perf_pmu_register(&perf_uprobe, "uprobe", -1);
8943#endif
8944}
8945
8946static void perf_event_free_filter(struct perf_event *event)
8947{
8948 ftrace_profile_free_filter(event);
8949}
8950
8951#ifdef CONFIG_BPF_SYSCALL
8952static void bpf_overflow_handler(struct perf_event *event,
8953 struct perf_sample_data *data,
8954 struct pt_regs *regs)
8955{
8956 struct bpf_perf_event_data_kern ctx = {
8957 .data = data,
8958 .event = event,
8959 };
8960 int ret = 0;
8961
8962 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
8963 preempt_disable();
8964 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8965 goto out;
8966 rcu_read_lock();
8967 ret = BPF_PROG_RUN(event->prog, &ctx);
8968 rcu_read_unlock();
8969out:
8970 __this_cpu_dec(bpf_prog_active);
8971 preempt_enable();
8972 if (!ret)
8973 return;
8974
8975 event->orig_overflow_handler(event, data, regs);
8976}
8977
8978static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8979{
8980 struct bpf_prog *prog;
8981
8982 if (event->overflow_handler_context)
8983 /* hw breakpoint or kernel counter */
8984 return -EINVAL;
8985
8986 if (event->prog)
8987 return -EEXIST;
8988
8989 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8990 if (IS_ERR(prog))
8991 return PTR_ERR(prog);
8992
8993 event->prog = prog;
8994 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8995 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8996 return 0;
8997}
8998
8999static void perf_event_free_bpf_handler(struct perf_event *event)
9000{
9001 struct bpf_prog *prog = event->prog;
9002
9003 if (!prog)
9004 return;
9005
9006 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
9007 event->prog = NULL;
9008 bpf_prog_put(prog);
9009}
9010#else
9011static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9012{
9013 return -EOPNOTSUPP;
9014}
9015static void perf_event_free_bpf_handler(struct perf_event *event)
9016{
9017}
9018#endif
9019
9020/*
9021 * returns true if the event is a tracepoint, or a kprobe/upprobe created
9022 * with perf_event_open()
9023 */
9024static inline bool perf_event_is_tracing(struct perf_event *event)
9025{
9026 if (event->pmu == &perf_tracepoint)
9027 return true;
9028#ifdef CONFIG_KPROBE_EVENTS
9029 if (event->pmu == &perf_kprobe)
9030 return true;
9031#endif
9032#ifdef CONFIG_UPROBE_EVENTS
9033 if (event->pmu == &perf_uprobe)
9034 return true;
9035#endif
9036 return false;
9037}
9038
9039static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9040{
9041 bool is_kprobe, is_tracepoint, is_syscall_tp;
9042 struct bpf_prog *prog;
9043 int ret;
9044
9045 if (!perf_event_is_tracing(event))
9046 return perf_event_set_bpf_handler(event, prog_fd);
9047
9048 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
9049 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
9050 is_syscall_tp = is_syscall_trace_event(event->tp_event);
9051 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
9052 /* bpf programs can only be attached to u/kprobe or tracepoint */
9053 return -EINVAL;
9054
9055 prog = bpf_prog_get(prog_fd);
9056 if (IS_ERR(prog))
9057 return PTR_ERR(prog);
9058
9059 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
9060 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
9061 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
9062 /* valid fd, but invalid bpf program type */
9063 bpf_prog_put(prog);
9064 return -EINVAL;
9065 }
9066
9067 /* Kprobe override only works for kprobes, not uprobes. */
9068 if (prog->kprobe_override &&
9069 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
9070 bpf_prog_put(prog);
9071 return -EINVAL;
9072 }
9073
9074 if (is_tracepoint || is_syscall_tp) {
9075 int off = trace_event_get_offsets(event->tp_event);
9076
9077 if (prog->aux->max_ctx_offset > off) {
9078 bpf_prog_put(prog);
9079 return -EACCES;
9080 }
9081 }
9082
9083 ret = perf_event_attach_bpf_prog(event, prog);
9084 if (ret)
9085 bpf_prog_put(prog);
9086 return ret;
9087}
9088
9089static void perf_event_free_bpf_prog(struct perf_event *event)
9090{
9091 if (!perf_event_is_tracing(event)) {
9092 perf_event_free_bpf_handler(event);
9093 return;
9094 }
9095 perf_event_detach_bpf_prog(event);
9096}
9097
9098#else
9099
9100static inline void perf_tp_register(void)
9101{
9102}
9103
9104static void perf_event_free_filter(struct perf_event *event)
9105{
9106}
9107
9108static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9109{
9110 return -ENOENT;
9111}
9112
9113static void perf_event_free_bpf_prog(struct perf_event *event)
9114{
9115}
9116#endif /* CONFIG_EVENT_TRACING */
9117
9118#ifdef CONFIG_HAVE_HW_BREAKPOINT
9119void perf_bp_event(struct perf_event *bp, void *data)
9120{
9121 struct perf_sample_data sample;
9122 struct pt_regs *regs = data;
9123
9124 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
9125
9126 if (!bp->hw.state && !perf_exclude_event(bp, regs))
9127 perf_swevent_event(bp, 1, &sample, regs);
9128}
9129#endif
9130
9131/*
9132 * Allocate a new address filter
9133 */
9134static struct perf_addr_filter *
9135perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
9136{
9137 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
9138 struct perf_addr_filter *filter;
9139
9140 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
9141 if (!filter)
9142 return NULL;
9143
9144 INIT_LIST_HEAD(&filter->entry);
9145 list_add_tail(&filter->entry, filters);
9146
9147 return filter;
9148}
9149
9150static void free_filters_list(struct list_head *filters)
9151{
9152 struct perf_addr_filter *filter, *iter;
9153
9154 list_for_each_entry_safe(filter, iter, filters, entry) {
9155 path_put(&filter->path);
9156 list_del(&filter->entry);
9157 kfree(filter);
9158 }
9159}
9160
9161/*
9162 * Free existing address filters and optionally install new ones
9163 */
9164static void perf_addr_filters_splice(struct perf_event *event,
9165 struct list_head *head)
9166{
9167 unsigned long flags;
9168 LIST_HEAD(list);
9169
9170 if (!has_addr_filter(event))
9171 return;
9172
9173 /* don't bother with children, they don't have their own filters */
9174 if (event->parent)
9175 return;
9176
9177 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
9178
9179 list_splice_init(&event->addr_filters.list, &list);
9180 if (head)
9181 list_splice(head, &event->addr_filters.list);
9182
9183 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
9184
9185 free_filters_list(&list);
9186}
9187
9188/*
9189 * Scan through mm's vmas and see if one of them matches the
9190 * @filter; if so, adjust filter's address range.
9191 * Called with mm::mmap_sem down for reading.
9192 */
9193static void perf_addr_filter_apply(struct perf_addr_filter *filter,
9194 struct mm_struct *mm,
9195 struct perf_addr_filter_range *fr)
9196{
9197 struct vm_area_struct *vma;
9198
9199 for (vma = mm->mmap; vma; vma = vma->vm_next) {
9200 if (!vma->vm_file)
9201 continue;
9202
9203 if (perf_addr_filter_vma_adjust(filter, vma, fr))
9204 return;
9205 }
9206}
9207
9208/*
9209 * Update event's address range filters based on the
9210 * task's existing mappings, if any.
9211 */
9212static void perf_event_addr_filters_apply(struct perf_event *event)
9213{
9214 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
9215 struct task_struct *task = READ_ONCE(event->ctx->task);
9216 struct perf_addr_filter *filter;
9217 struct mm_struct *mm = NULL;
9218 unsigned int count = 0;
9219 unsigned long flags;
9220
9221 /*
9222 * We may observe TASK_TOMBSTONE, which means that the event tear-down
9223 * will stop on the parent's child_mutex that our caller is also holding
9224 */
9225 if (task == TASK_TOMBSTONE)
9226 return;
9227
9228 if (ifh->nr_file_filters) {
9229 mm = get_task_mm(event->ctx->task);
9230 if (!mm)
9231 goto restart;
9232
9233 down_read(&mm->mmap_sem);
9234 }
9235
9236 raw_spin_lock_irqsave(&ifh->lock, flags);
9237 list_for_each_entry(filter, &ifh->list, entry) {
9238 if (filter->path.dentry) {
9239 /*
9240 * Adjust base offset if the filter is associated to a
9241 * binary that needs to be mapped:
9242 */
9243 event->addr_filter_ranges[count].start = 0;
9244 event->addr_filter_ranges[count].size = 0;
9245
9246 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
9247 } else {
9248 event->addr_filter_ranges[count].start = filter->offset;
9249 event->addr_filter_ranges[count].size = filter->size;
9250 }
9251
9252 count++;
9253 }
9254
9255 event->addr_filters_gen++;
9256 raw_spin_unlock_irqrestore(&ifh->lock, flags);
9257
9258 if (ifh->nr_file_filters) {
9259 up_read(&mm->mmap_sem);
9260
9261 mmput(mm);
9262 }
9263
9264restart:
9265 perf_event_stop(event, 1);
9266}
9267
9268/*
9269 * Address range filtering: limiting the data to certain
9270 * instruction address ranges. Filters are ioctl()ed to us from
9271 * userspace as ascii strings.
9272 *
9273 * Filter string format:
9274 *
9275 * ACTION RANGE_SPEC
9276 * where ACTION is one of the
9277 * * "filter": limit the trace to this region
9278 * * "start": start tracing from this address
9279 * * "stop": stop tracing at this address/region;
9280 * RANGE_SPEC is
9281 * * for kernel addresses: <start address>[/<size>]
9282 * * for object files: <start address>[/<size>]@</path/to/object/file>
9283 *
9284 * if <size> is not specified or is zero, the range is treated as a single
9285 * address; not valid for ACTION=="filter".
9286 */
9287enum {
9288 IF_ACT_NONE = -1,
9289 IF_ACT_FILTER,
9290 IF_ACT_START,
9291 IF_ACT_STOP,
9292 IF_SRC_FILE,
9293 IF_SRC_KERNEL,
9294 IF_SRC_FILEADDR,
9295 IF_SRC_KERNELADDR,
9296};
9297
9298enum {
9299 IF_STATE_ACTION = 0,
9300 IF_STATE_SOURCE,
9301 IF_STATE_END,
9302};
9303
9304static const match_table_t if_tokens = {
9305 { IF_ACT_FILTER, "filter" },
9306 { IF_ACT_START, "start" },
9307 { IF_ACT_STOP, "stop" },
9308 { IF_SRC_FILE, "%u/%u@%s" },
9309 { IF_SRC_KERNEL, "%u/%u" },
9310 { IF_SRC_FILEADDR, "%u@%s" },
9311 { IF_SRC_KERNELADDR, "%u" },
9312 { IF_ACT_NONE, NULL },
9313};
9314
9315/*
9316 * Address filter string parser
9317 */
9318static int
9319perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
9320 struct list_head *filters)
9321{
9322 struct perf_addr_filter *filter = NULL;
9323 char *start, *orig, *filename = NULL;
9324 substring_t args[MAX_OPT_ARGS];
9325 int state = IF_STATE_ACTION, token;
9326 unsigned int kernel = 0;
9327 int ret = -EINVAL;
9328
9329 orig = fstr = kstrdup(fstr, GFP_KERNEL);
9330 if (!fstr)
9331 return -ENOMEM;
9332
9333 while ((start = strsep(&fstr, " ,\n")) != NULL) {
9334 static const enum perf_addr_filter_action_t actions[] = {
9335 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
9336 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
9337 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
9338 };
9339 ret = -EINVAL;
9340
9341 if (!*start)
9342 continue;
9343
9344 /* filter definition begins */
9345 if (state == IF_STATE_ACTION) {
9346 filter = perf_addr_filter_new(event, filters);
9347 if (!filter)
9348 goto fail;
9349 }
9350
9351 token = match_token(start, if_tokens, args);
9352 switch (token) {
9353 case IF_ACT_FILTER:
9354 case IF_ACT_START:
9355 case IF_ACT_STOP:
9356 if (state != IF_STATE_ACTION)
9357 goto fail;
9358
9359 filter->action = actions[token];
9360 state = IF_STATE_SOURCE;
9361 break;
9362
9363 case IF_SRC_KERNELADDR:
9364 case IF_SRC_KERNEL:
9365 kernel = 1;
9366 /* fall through */
9367
9368 case IF_SRC_FILEADDR:
9369 case IF_SRC_FILE:
9370 if (state != IF_STATE_SOURCE)
9371 goto fail;
9372
9373 *args[0].to = 0;
9374 ret = kstrtoul(args[0].from, 0, &filter->offset);
9375 if (ret)
9376 goto fail;
9377
9378 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
9379 *args[1].to = 0;
9380 ret = kstrtoul(args[1].from, 0, &filter->size);
9381 if (ret)
9382 goto fail;
9383 }
9384
9385 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9386 int fpos = token == IF_SRC_FILE ? 2 : 1;
9387
9388 filename = match_strdup(&args[fpos]);
9389 if (!filename) {
9390 ret = -ENOMEM;
9391 goto fail;
9392 }
9393 }
9394
9395 state = IF_STATE_END;
9396 break;
9397
9398 default:
9399 goto fail;
9400 }
9401
9402 /*
9403 * Filter definition is fully parsed, validate and install it.
9404 * Make sure that it doesn't contradict itself or the event's
9405 * attribute.
9406 */
9407 if (state == IF_STATE_END) {
9408 ret = -EINVAL;
9409 if (kernel && event->attr.exclude_kernel)
9410 goto fail;
9411
9412 /*
9413 * ACTION "filter" must have a non-zero length region
9414 * specified.
9415 */
9416 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9417 !filter->size)
9418 goto fail;
9419
9420 if (!kernel) {
9421 if (!filename)
9422 goto fail;
9423
9424 /*
9425 * For now, we only support file-based filters
9426 * in per-task events; doing so for CPU-wide
9427 * events requires additional context switching
9428 * trickery, since same object code will be
9429 * mapped at different virtual addresses in
9430 * different processes.
9431 */
9432 ret = -EOPNOTSUPP;
9433 if (!event->ctx->task)
9434 goto fail_free_name;
9435
9436 /* look up the path and grab its inode */
9437 ret = kern_path(filename, LOOKUP_FOLLOW,
9438 &filter->path);
9439 if (ret)
9440 goto fail_free_name;
9441
9442 kfree(filename);
9443 filename = NULL;
9444
9445 ret = -EINVAL;
9446 if (!filter->path.dentry ||
9447 !S_ISREG(d_inode(filter->path.dentry)
9448 ->i_mode))
9449 goto fail;
9450
9451 event->addr_filters.nr_file_filters++;
9452 }
9453
9454 /* ready to consume more filters */
9455 state = IF_STATE_ACTION;
9456 filter = NULL;
9457 }
9458 }
9459
9460 if (state != IF_STATE_ACTION)
9461 goto fail;
9462
9463 kfree(orig);
9464
9465 return 0;
9466
9467fail_free_name:
9468 kfree(filename);
9469fail:
9470 free_filters_list(filters);
9471 kfree(orig);
9472
9473 return ret;
9474}
9475
9476static int
9477perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
9478{
9479 LIST_HEAD(filters);
9480 int ret;
9481
9482 /*
9483 * Since this is called in perf_ioctl() path, we're already holding
9484 * ctx::mutex.
9485 */
9486 lockdep_assert_held(&event->ctx->mutex);
9487
9488 if (WARN_ON_ONCE(event->parent))
9489 return -EINVAL;
9490
9491 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
9492 if (ret)
9493 goto fail_clear_files;
9494
9495 ret = event->pmu->addr_filters_validate(&filters);
9496 if (ret)
9497 goto fail_free_filters;
9498
9499 /* remove existing filters, if any */
9500 perf_addr_filters_splice(event, &filters);
9501
9502 /* install new filters */
9503 perf_event_for_each_child(event, perf_event_addr_filters_apply);
9504
9505 return ret;
9506
9507fail_free_filters:
9508 free_filters_list(&filters);
9509
9510fail_clear_files:
9511 event->addr_filters.nr_file_filters = 0;
9512
9513 return ret;
9514}
9515
9516static int perf_event_set_filter(struct perf_event *event, void __user *arg)
9517{
9518 int ret = -EINVAL;
9519 char *filter_str;
9520
9521 filter_str = strndup_user(arg, PAGE_SIZE);
9522 if (IS_ERR(filter_str))
9523 return PTR_ERR(filter_str);
9524
9525#ifdef CONFIG_EVENT_TRACING
9526 if (perf_event_is_tracing(event)) {
9527 struct perf_event_context *ctx = event->ctx;
9528
9529 /*
9530 * Beware, here be dragons!!
9531 *
9532 * the tracepoint muck will deadlock against ctx->mutex, but
9533 * the tracepoint stuff does not actually need it. So
9534 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
9535 * already have a reference on ctx.
9536 *
9537 * This can result in event getting moved to a different ctx,
9538 * but that does not affect the tracepoint state.
9539 */
9540 mutex_unlock(&ctx->mutex);
9541 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
9542 mutex_lock(&ctx->mutex);
9543 } else
9544#endif
9545 if (has_addr_filter(event))
9546 ret = perf_event_set_addr_filter(event, filter_str);
9547
9548 kfree(filter_str);
9549 return ret;
9550}
9551
9552/*
9553 * hrtimer based swevent callback
9554 */
9555
9556static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
9557{
9558 enum hrtimer_restart ret = HRTIMER_RESTART;
9559 struct perf_sample_data data;
9560 struct pt_regs *regs;
9561 struct perf_event *event;
9562 u64 period;
9563
9564 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
9565
9566 if (event->state != PERF_EVENT_STATE_ACTIVE)
9567 return HRTIMER_NORESTART;
9568
9569 event->pmu->read(event);
9570
9571 perf_sample_data_init(&data, 0, event->hw.last_period);
9572 regs = get_irq_regs();
9573
9574 if (regs && !perf_exclude_event(event, regs)) {
9575 if (!(event->attr.exclude_idle && is_idle_task(current)))
9576 if (__perf_event_overflow(event, 1, &data, regs))
9577 ret = HRTIMER_NORESTART;
9578 }
9579
9580 period = max_t(u64, 10000, event->hw.sample_period);
9581 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
9582
9583 return ret;
9584}
9585
9586static void perf_swevent_start_hrtimer(struct perf_event *event)
9587{
9588 struct hw_perf_event *hwc = &event->hw;
9589 s64 period;
9590
9591 if (!is_sampling_event(event))
9592 return;
9593
9594 period = local64_read(&hwc->period_left);
9595 if (period) {
9596 if (period < 0)
9597 period = 10000;
9598
9599 local64_set(&hwc->period_left, 0);
9600 } else {
9601 period = max_t(u64, 10000, hwc->sample_period);
9602 }
9603 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
9604 HRTIMER_MODE_REL_PINNED_HARD);
9605}
9606
9607static void perf_swevent_cancel_hrtimer(struct perf_event *event)
9608{
9609 struct hw_perf_event *hwc = &event->hw;
9610
9611 if (is_sampling_event(event)) {
9612 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
9613 local64_set(&hwc->period_left, ktime_to_ns(remaining));
9614
9615 hrtimer_cancel(&hwc->hrtimer);
9616 }
9617}
9618
9619static void perf_swevent_init_hrtimer(struct perf_event *event)
9620{
9621 struct hw_perf_event *hwc = &event->hw;
9622
9623 if (!is_sampling_event(event))
9624 return;
9625
9626 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
9627 hwc->hrtimer.function = perf_swevent_hrtimer;
9628
9629 /*
9630 * Since hrtimers have a fixed rate, we can do a static freq->period
9631 * mapping and avoid the whole period adjust feedback stuff.
9632 */
9633 if (event->attr.freq) {
9634 long freq = event->attr.sample_freq;
9635
9636 event->attr.sample_period = NSEC_PER_SEC / freq;
9637 hwc->sample_period = event->attr.sample_period;
9638 local64_set(&hwc->period_left, hwc->sample_period);
9639 hwc->last_period = hwc->sample_period;
9640 event->attr.freq = 0;
9641 }
9642}
9643
9644/*
9645 * Software event: cpu wall time clock
9646 */
9647
9648static void cpu_clock_event_update(struct perf_event *event)
9649{
9650 s64 prev;
9651 u64 now;
9652
9653 now = local_clock();
9654 prev = local64_xchg(&event->hw.prev_count, now);
9655 local64_add(now - prev, &event->count);
9656}
9657
9658static void cpu_clock_event_start(struct perf_event *event, int flags)
9659{
9660 local64_set(&event->hw.prev_count, local_clock());
9661 perf_swevent_start_hrtimer(event);
9662}
9663
9664static void cpu_clock_event_stop(struct perf_event *event, int flags)
9665{
9666 perf_swevent_cancel_hrtimer(event);
9667 cpu_clock_event_update(event);
9668}
9669
9670static int cpu_clock_event_add(struct perf_event *event, int flags)
9671{
9672 if (flags & PERF_EF_START)
9673 cpu_clock_event_start(event, flags);
9674 perf_event_update_userpage(event);
9675
9676 return 0;
9677}
9678
9679static void cpu_clock_event_del(struct perf_event *event, int flags)
9680{
9681 cpu_clock_event_stop(event, flags);
9682}
9683
9684static void cpu_clock_event_read(struct perf_event *event)
9685{
9686 cpu_clock_event_update(event);
9687}
9688
9689static int cpu_clock_event_init(struct perf_event *event)
9690{
9691 if (event->attr.type != PERF_TYPE_SOFTWARE)
9692 return -ENOENT;
9693
9694 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
9695 return -ENOENT;
9696
9697 /*
9698 * no branch sampling for software events
9699 */
9700 if (has_branch_stack(event))
9701 return -EOPNOTSUPP;
9702
9703 perf_swevent_init_hrtimer(event);
9704
9705 return 0;
9706}
9707
9708static struct pmu perf_cpu_clock = {
9709 .task_ctx_nr = perf_sw_context,
9710
9711 .capabilities = PERF_PMU_CAP_NO_NMI,
9712
9713 .event_init = cpu_clock_event_init,
9714 .add = cpu_clock_event_add,
9715 .del = cpu_clock_event_del,
9716 .start = cpu_clock_event_start,
9717 .stop = cpu_clock_event_stop,
9718 .read = cpu_clock_event_read,
9719};
9720
9721/*
9722 * Software event: task time clock
9723 */
9724
9725static void task_clock_event_update(struct perf_event *event, u64 now)
9726{
9727 u64 prev;
9728 s64 delta;
9729
9730 prev = local64_xchg(&event->hw.prev_count, now);
9731 delta = now - prev;
9732 local64_add(delta, &event->count);
9733}
9734
9735static void task_clock_event_start(struct perf_event *event, int flags)
9736{
9737 local64_set(&event->hw.prev_count, event->ctx->time);
9738 perf_swevent_start_hrtimer(event);
9739}
9740
9741static void task_clock_event_stop(struct perf_event *event, int flags)
9742{
9743 perf_swevent_cancel_hrtimer(event);
9744 task_clock_event_update(event, event->ctx->time);
9745}
9746
9747static int task_clock_event_add(struct perf_event *event, int flags)
9748{
9749 if (flags & PERF_EF_START)
9750 task_clock_event_start(event, flags);
9751 perf_event_update_userpage(event);
9752
9753 return 0;
9754}
9755
9756static void task_clock_event_del(struct perf_event *event, int flags)
9757{
9758 task_clock_event_stop(event, PERF_EF_UPDATE);
9759}
9760
9761static void task_clock_event_read(struct perf_event *event)
9762{
9763 u64 now = perf_clock();
9764 u64 delta = now - event->ctx->timestamp;
9765 u64 time = event->ctx->time + delta;
9766
9767 task_clock_event_update(event, time);
9768}
9769
9770static int task_clock_event_init(struct perf_event *event)
9771{
9772 if (event->attr.type != PERF_TYPE_SOFTWARE)
9773 return -ENOENT;
9774
9775 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
9776 return -ENOENT;
9777
9778 /*
9779 * no branch sampling for software events
9780 */
9781 if (has_branch_stack(event))
9782 return -EOPNOTSUPP;
9783
9784 perf_swevent_init_hrtimer(event);
9785
9786 return 0;
9787}
9788
9789static struct pmu perf_task_clock = {
9790 .task_ctx_nr = perf_sw_context,
9791
9792 .capabilities = PERF_PMU_CAP_NO_NMI,
9793
9794 .event_init = task_clock_event_init,
9795 .add = task_clock_event_add,
9796 .del = task_clock_event_del,
9797 .start = task_clock_event_start,
9798 .stop = task_clock_event_stop,
9799 .read = task_clock_event_read,
9800};
9801
9802static void perf_pmu_nop_void(struct pmu *pmu)
9803{
9804}
9805
9806static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
9807{
9808}
9809
9810static int perf_pmu_nop_int(struct pmu *pmu)
9811{
9812 return 0;
9813}
9814
9815static int perf_event_nop_int(struct perf_event *event, u64 value)
9816{
9817 return 0;
9818}
9819
9820static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
9821
9822static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
9823{
9824 __this_cpu_write(nop_txn_flags, flags);
9825
9826 if (flags & ~PERF_PMU_TXN_ADD)
9827 return;
9828
9829 perf_pmu_disable(pmu);
9830}
9831
9832static int perf_pmu_commit_txn(struct pmu *pmu)
9833{
9834 unsigned int flags = __this_cpu_read(nop_txn_flags);
9835
9836 __this_cpu_write(nop_txn_flags, 0);
9837
9838 if (flags & ~PERF_PMU_TXN_ADD)
9839 return 0;
9840
9841 perf_pmu_enable(pmu);
9842 return 0;
9843}
9844
9845static void perf_pmu_cancel_txn(struct pmu *pmu)
9846{
9847 unsigned int flags = __this_cpu_read(nop_txn_flags);
9848
9849 __this_cpu_write(nop_txn_flags, 0);
9850
9851 if (flags & ~PERF_PMU_TXN_ADD)
9852 return;
9853
9854 perf_pmu_enable(pmu);
9855}
9856
9857static int perf_event_idx_default(struct perf_event *event)
9858{
9859 return 0;
9860}
9861
9862/*
9863 * Ensures all contexts with the same task_ctx_nr have the same
9864 * pmu_cpu_context too.
9865 */
9866static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
9867{
9868 struct pmu *pmu;
9869
9870 if (ctxn < 0)
9871 return NULL;
9872
9873 list_for_each_entry(pmu, &pmus, entry) {
9874 if (pmu->task_ctx_nr == ctxn)
9875 return pmu->pmu_cpu_context;
9876 }
9877
9878 return NULL;
9879}
9880
9881static void free_pmu_context(struct pmu *pmu)
9882{
9883 /*
9884 * Static contexts such as perf_sw_context have a global lifetime
9885 * and may be shared between different PMUs. Avoid freeing them
9886 * when a single PMU is going away.
9887 */
9888 if (pmu->task_ctx_nr > perf_invalid_context)
9889 return;
9890
9891 free_percpu(pmu->pmu_cpu_context);
9892}
9893
9894/*
9895 * Let userspace know that this PMU supports address range filtering:
9896 */
9897static ssize_t nr_addr_filters_show(struct device *dev,
9898 struct device_attribute *attr,
9899 char *page)
9900{
9901 struct pmu *pmu = dev_get_drvdata(dev);
9902
9903 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
9904}
9905DEVICE_ATTR_RO(nr_addr_filters);
9906
9907static struct idr pmu_idr;
9908
9909static ssize_t
9910type_show(struct device *dev, struct device_attribute *attr, char *page)
9911{
9912 struct pmu *pmu = dev_get_drvdata(dev);
9913
9914 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
9915}
9916static DEVICE_ATTR_RO(type);
9917
9918static ssize_t
9919perf_event_mux_interval_ms_show(struct device *dev,
9920 struct device_attribute *attr,
9921 char *page)
9922{
9923 struct pmu *pmu = dev_get_drvdata(dev);
9924
9925 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9926}
9927
9928static DEFINE_MUTEX(mux_interval_mutex);
9929
9930static ssize_t
9931perf_event_mux_interval_ms_store(struct device *dev,
9932 struct device_attribute *attr,
9933 const char *buf, size_t count)
9934{
9935 struct pmu *pmu = dev_get_drvdata(dev);
9936 int timer, cpu, ret;
9937
9938 ret = kstrtoint(buf, 0, &timer);
9939 if (ret)
9940 return ret;
9941
9942 if (timer < 1)
9943 return -EINVAL;
9944
9945 /* same value, noting to do */
9946 if (timer == pmu->hrtimer_interval_ms)
9947 return count;
9948
9949 mutex_lock(&mux_interval_mutex);
9950 pmu->hrtimer_interval_ms = timer;
9951
9952 /* update all cpuctx for this PMU */
9953 cpus_read_lock();
9954 for_each_online_cpu(cpu) {
9955 struct perf_cpu_context *cpuctx;
9956 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9957 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9958
9959 cpu_function_call(cpu,
9960 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
9961 }
9962 cpus_read_unlock();
9963 mutex_unlock(&mux_interval_mutex);
9964
9965 return count;
9966}
9967static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9968
9969static struct attribute *pmu_dev_attrs[] = {
9970 &dev_attr_type.attr,
9971 &dev_attr_perf_event_mux_interval_ms.attr,
9972 NULL,
9973};
9974ATTRIBUTE_GROUPS(pmu_dev);
9975
9976static int pmu_bus_running;
9977static struct bus_type pmu_bus = {
9978 .name = "event_source",
9979 .dev_groups = pmu_dev_groups,
9980};
9981
9982static void pmu_dev_release(struct device *dev)
9983{
9984 kfree(dev);
9985}
9986
9987static int pmu_dev_alloc(struct pmu *pmu)
9988{
9989 int ret = -ENOMEM;
9990
9991 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9992 if (!pmu->dev)
9993 goto out;
9994
9995 pmu->dev->groups = pmu->attr_groups;
9996 device_initialize(pmu->dev);
9997 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9998 if (ret)
9999 goto free_dev;
10000
10001 dev_set_drvdata(pmu->dev, pmu);
10002 pmu->dev->bus = &pmu_bus;
10003 pmu->dev->release = pmu_dev_release;
10004 ret = device_add(pmu->dev);
10005 if (ret)
10006 goto free_dev;
10007
10008 /* For PMUs with address filters, throw in an extra attribute: */
10009 if (pmu->nr_addr_filters)
10010 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
10011
10012 if (ret)
10013 goto del_dev;
10014
10015 if (pmu->attr_update)
10016 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
10017
10018 if (ret)
10019 goto del_dev;
10020
10021out:
10022 return ret;
10023
10024del_dev:
10025 device_del(pmu->dev);
10026
10027free_dev:
10028 put_device(pmu->dev);
10029 goto out;
10030}
10031
10032static struct lock_class_key cpuctx_mutex;
10033static struct lock_class_key cpuctx_lock;
10034
10035int perf_pmu_register(struct pmu *pmu, const char *name, int type)
10036{
10037 int cpu, ret;
10038
10039 mutex_lock(&pmus_lock);
10040 ret = -ENOMEM;
10041 pmu->pmu_disable_count = alloc_percpu(int);
10042 if (!pmu->pmu_disable_count)
10043 goto unlock;
10044
10045 pmu->type = -1;
10046 if (!name)
10047 goto skip_type;
10048 pmu->name = name;
10049
10050 if (type < 0) {
10051 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
10052 if (type < 0) {
10053 ret = type;
10054 goto free_pdc;
10055 }
10056 }
10057 pmu->type = type;
10058
10059 if (pmu_bus_running) {
10060 ret = pmu_dev_alloc(pmu);
10061 if (ret)
10062 goto free_idr;
10063 }
10064
10065skip_type:
10066 if (pmu->task_ctx_nr == perf_hw_context) {
10067 static int hw_context_taken = 0;
10068
10069 /*
10070 * Other than systems with heterogeneous CPUs, it never makes
10071 * sense for two PMUs to share perf_hw_context. PMUs which are
10072 * uncore must use perf_invalid_context.
10073 */
10074 if (WARN_ON_ONCE(hw_context_taken &&
10075 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
10076 pmu->task_ctx_nr = perf_invalid_context;
10077
10078 hw_context_taken = 1;
10079 }
10080
10081 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
10082 if (pmu->pmu_cpu_context)
10083 goto got_cpu_context;
10084
10085 ret = -ENOMEM;
10086 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
10087 if (!pmu->pmu_cpu_context)
10088 goto free_dev;
10089
10090 for_each_possible_cpu(cpu) {
10091 struct perf_cpu_context *cpuctx;
10092
10093 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10094 __perf_event_init_context(&cpuctx->ctx);
10095 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
10096 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
10097 cpuctx->ctx.pmu = pmu;
10098 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
10099
10100 __perf_mux_hrtimer_init(cpuctx, cpu);
10101 }
10102
10103got_cpu_context:
10104 if (!pmu->start_txn) {
10105 if (pmu->pmu_enable) {
10106 /*
10107 * If we have pmu_enable/pmu_disable calls, install
10108 * transaction stubs that use that to try and batch
10109 * hardware accesses.
10110 */
10111 pmu->start_txn = perf_pmu_start_txn;
10112 pmu->commit_txn = perf_pmu_commit_txn;
10113 pmu->cancel_txn = perf_pmu_cancel_txn;
10114 } else {
10115 pmu->start_txn = perf_pmu_nop_txn;
10116 pmu->commit_txn = perf_pmu_nop_int;
10117 pmu->cancel_txn = perf_pmu_nop_void;
10118 }
10119 }
10120
10121 if (!pmu->pmu_enable) {
10122 pmu->pmu_enable = perf_pmu_nop_void;
10123 pmu->pmu_disable = perf_pmu_nop_void;
10124 }
10125
10126 if (!pmu->check_period)
10127 pmu->check_period = perf_event_nop_int;
10128
10129 if (!pmu->event_idx)
10130 pmu->event_idx = perf_event_idx_default;
10131
10132 list_add_rcu(&pmu->entry, &pmus);
10133 atomic_set(&pmu->exclusive_cnt, 0);
10134 ret = 0;
10135unlock:
10136 mutex_unlock(&pmus_lock);
10137
10138 return ret;
10139
10140free_dev:
10141 device_del(pmu->dev);
10142 put_device(pmu->dev);
10143
10144free_idr:
10145 if (pmu->type >= PERF_TYPE_MAX)
10146 idr_remove(&pmu_idr, pmu->type);
10147
10148free_pdc:
10149 free_percpu(pmu->pmu_disable_count);
10150 goto unlock;
10151}
10152EXPORT_SYMBOL_GPL(perf_pmu_register);
10153
10154void perf_pmu_unregister(struct pmu *pmu)
10155{
10156 mutex_lock(&pmus_lock);
10157 list_del_rcu(&pmu->entry);
10158
10159 /*
10160 * We dereference the pmu list under both SRCU and regular RCU, so
10161 * synchronize against both of those.
10162 */
10163 synchronize_srcu(&pmus_srcu);
10164 synchronize_rcu();
10165
10166 free_percpu(pmu->pmu_disable_count);
10167 if (pmu->type >= PERF_TYPE_MAX)
10168 idr_remove(&pmu_idr, pmu->type);
10169 if (pmu_bus_running) {
10170 if (pmu->nr_addr_filters)
10171 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
10172 device_del(pmu->dev);
10173 put_device(pmu->dev);
10174 }
10175 free_pmu_context(pmu);
10176 mutex_unlock(&pmus_lock);
10177}
10178EXPORT_SYMBOL_GPL(perf_pmu_unregister);
10179
10180static inline bool has_extended_regs(struct perf_event *event)
10181{
10182 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
10183 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
10184}
10185
10186static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
10187{
10188 struct perf_event_context *ctx = NULL;
10189 int ret;
10190
10191 if (!try_module_get(pmu->module))
10192 return -ENODEV;
10193
10194 /*
10195 * A number of pmu->event_init() methods iterate the sibling_list to,
10196 * for example, validate if the group fits on the PMU. Therefore,
10197 * if this is a sibling event, acquire the ctx->mutex to protect
10198 * the sibling_list.
10199 */
10200 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
10201 /*
10202 * This ctx->mutex can nest when we're called through
10203 * inheritance. See the perf_event_ctx_lock_nested() comment.
10204 */
10205 ctx = perf_event_ctx_lock_nested(event->group_leader,
10206 SINGLE_DEPTH_NESTING);
10207 BUG_ON(!ctx);
10208 }
10209
10210 event->pmu = pmu;
10211 ret = pmu->event_init(event);
10212
10213 if (ctx)
10214 perf_event_ctx_unlock(event->group_leader, ctx);
10215
10216 if (!ret) {
10217 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
10218 has_extended_regs(event))
10219 ret = -EOPNOTSUPP;
10220
10221 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
10222 event_has_any_exclude_flag(event))
10223 ret = -EINVAL;
10224
10225 if (ret && event->destroy)
10226 event->destroy(event);
10227 }
10228
10229 if (ret)
10230 module_put(pmu->module);
10231
10232 return ret;
10233}
10234
10235static struct pmu *perf_init_event(struct perf_event *event)
10236{
10237 struct pmu *pmu;
10238 int idx;
10239 int ret;
10240
10241 idx = srcu_read_lock(&pmus_srcu);
10242
10243 /* Try parent's PMU first: */
10244 if (event->parent && event->parent->pmu) {
10245 pmu = event->parent->pmu;
10246 ret = perf_try_init_event(pmu, event);
10247 if (!ret)
10248 goto unlock;
10249 }
10250
10251 rcu_read_lock();
10252 pmu = idr_find(&pmu_idr, event->attr.type);
10253 rcu_read_unlock();
10254 if (pmu) {
10255 ret = perf_try_init_event(pmu, event);
10256 if (ret)
10257 pmu = ERR_PTR(ret);
10258 goto unlock;
10259 }
10260
10261 list_for_each_entry_rcu(pmu, &pmus, entry) {
10262 ret = perf_try_init_event(pmu, event);
10263 if (!ret)
10264 goto unlock;
10265
10266 if (ret != -ENOENT) {
10267 pmu = ERR_PTR(ret);
10268 goto unlock;
10269 }
10270 }
10271 pmu = ERR_PTR(-ENOENT);
10272unlock:
10273 srcu_read_unlock(&pmus_srcu, idx);
10274
10275 return pmu;
10276}
10277
10278static void attach_sb_event(struct perf_event *event)
10279{
10280 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
10281
10282 raw_spin_lock(&pel->lock);
10283 list_add_rcu(&event->sb_list, &pel->list);
10284 raw_spin_unlock(&pel->lock);
10285}
10286
10287/*
10288 * We keep a list of all !task (and therefore per-cpu) events
10289 * that need to receive side-band records.
10290 *
10291 * This avoids having to scan all the various PMU per-cpu contexts
10292 * looking for them.
10293 */
10294static void account_pmu_sb_event(struct perf_event *event)
10295{
10296 if (is_sb_event(event))
10297 attach_sb_event(event);
10298}
10299
10300static void account_event_cpu(struct perf_event *event, int cpu)
10301{
10302 if (event->parent)
10303 return;
10304
10305 if (is_cgroup_event(event))
10306 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
10307}
10308
10309/* Freq events need the tick to stay alive (see perf_event_task_tick). */
10310static void account_freq_event_nohz(void)
10311{
10312#ifdef CONFIG_NO_HZ_FULL
10313 /* Lock so we don't race with concurrent unaccount */
10314 spin_lock(&nr_freq_lock);
10315 if (atomic_inc_return(&nr_freq_events) == 1)
10316 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
10317 spin_unlock(&nr_freq_lock);
10318#endif
10319}
10320
10321static void account_freq_event(void)
10322{
10323 if (tick_nohz_full_enabled())
10324 account_freq_event_nohz();
10325 else
10326 atomic_inc(&nr_freq_events);
10327}
10328
10329
10330static void account_event(struct perf_event *event)
10331{
10332 bool inc = false;
10333
10334 if (event->parent)
10335 return;
10336
10337 if (event->attach_state & PERF_ATTACH_TASK)
10338 inc = true;
10339 if (event->attr.mmap || event->attr.mmap_data)
10340 atomic_inc(&nr_mmap_events);
10341 if (event->attr.comm)
10342 atomic_inc(&nr_comm_events);
10343 if (event->attr.namespaces)
10344 atomic_inc(&nr_namespaces_events);
10345 if (event->attr.task)
10346 atomic_inc(&nr_task_events);
10347 if (event->attr.freq)
10348 account_freq_event();
10349 if (event->attr.context_switch) {
10350 atomic_inc(&nr_switch_events);
10351 inc = true;
10352 }
10353 if (has_branch_stack(event))
10354 inc = true;
10355 if (is_cgroup_event(event))
10356 inc = true;
10357 if (event->attr.ksymbol)
10358 atomic_inc(&nr_ksymbol_events);
10359 if (event->attr.bpf_event)
10360 atomic_inc(&nr_bpf_events);
10361
10362 if (inc) {
10363 /*
10364 * We need the mutex here because static_branch_enable()
10365 * must complete *before* the perf_sched_count increment
10366 * becomes visible.
10367 */
10368 if (atomic_inc_not_zero(&perf_sched_count))
10369 goto enabled;
10370
10371 mutex_lock(&perf_sched_mutex);
10372 if (!atomic_read(&perf_sched_count)) {
10373 static_branch_enable(&perf_sched_events);
10374 /*
10375 * Guarantee that all CPUs observe they key change and
10376 * call the perf scheduling hooks before proceeding to
10377 * install events that need them.
10378 */
10379 synchronize_rcu();
10380 }
10381 /*
10382 * Now that we have waited for the sync_sched(), allow further
10383 * increments to by-pass the mutex.
10384 */
10385 atomic_inc(&perf_sched_count);
10386 mutex_unlock(&perf_sched_mutex);
10387 }
10388enabled:
10389
10390 account_event_cpu(event, event->cpu);
10391
10392 account_pmu_sb_event(event);
10393}
10394
10395/*
10396 * Allocate and initialize an event structure
10397 */
10398static struct perf_event *
10399perf_event_alloc(struct perf_event_attr *attr, int cpu,
10400 struct task_struct *task,
10401 struct perf_event *group_leader,
10402 struct perf_event *parent_event,
10403 perf_overflow_handler_t overflow_handler,
10404 void *context, int cgroup_fd)
10405{
10406 struct pmu *pmu;
10407 struct perf_event *event;
10408 struct hw_perf_event *hwc;
10409 long err = -EINVAL;
10410
10411 if ((unsigned)cpu >= nr_cpu_ids) {
10412 if (!task || cpu != -1)
10413 return ERR_PTR(-EINVAL);
10414 }
10415
10416 event = kzalloc(sizeof(*event), GFP_KERNEL);
10417 if (!event)
10418 return ERR_PTR(-ENOMEM);
10419
10420 /*
10421 * Single events are their own group leaders, with an
10422 * empty sibling list:
10423 */
10424 if (!group_leader)
10425 group_leader = event;
10426
10427 mutex_init(&event->child_mutex);
10428 INIT_LIST_HEAD(&event->child_list);
10429
10430 INIT_LIST_HEAD(&event->event_entry);
10431 INIT_LIST_HEAD(&event->sibling_list);
10432 INIT_LIST_HEAD(&event->active_list);
10433 init_event_group(event);
10434 INIT_LIST_HEAD(&event->rb_entry);
10435 INIT_LIST_HEAD(&event->active_entry);
10436 INIT_LIST_HEAD(&event->addr_filters.list);
10437 INIT_HLIST_NODE(&event->hlist_entry);
10438
10439
10440 init_waitqueue_head(&event->waitq);
10441 event->pending_disable = -1;
10442 init_irq_work(&event->pending, perf_pending_event);
10443
10444 mutex_init(&event->mmap_mutex);
10445 raw_spin_lock_init(&event->addr_filters.lock);
10446
10447 atomic_long_set(&event->refcount, 1);
10448 event->cpu = cpu;
10449 event->attr = *attr;
10450 event->group_leader = group_leader;
10451 event->pmu = NULL;
10452 event->oncpu = -1;
10453
10454 event->parent = parent_event;
10455
10456 event->ns = get_pid_ns(task_active_pid_ns(current));
10457 event->id = atomic64_inc_return(&perf_event_id);
10458
10459 event->state = PERF_EVENT_STATE_INACTIVE;
10460
10461 if (task) {
10462 event->attach_state = PERF_ATTACH_TASK;
10463 /*
10464 * XXX pmu::event_init needs to know what task to account to
10465 * and we cannot use the ctx information because we need the
10466 * pmu before we get a ctx.
10467 */
10468 event->hw.target = get_task_struct(task);
10469 }
10470
10471 event->clock = &local_clock;
10472 if (parent_event)
10473 event->clock = parent_event->clock;
10474
10475 if (!overflow_handler && parent_event) {
10476 overflow_handler = parent_event->overflow_handler;
10477 context = parent_event->overflow_handler_context;
10478#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
10479 if (overflow_handler == bpf_overflow_handler) {
10480 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
10481
10482 if (IS_ERR(prog)) {
10483 err = PTR_ERR(prog);
10484 goto err_ns;
10485 }
10486 event->prog = prog;
10487 event->orig_overflow_handler =
10488 parent_event->orig_overflow_handler;
10489 }
10490#endif
10491 }
10492
10493 if (overflow_handler) {
10494 event->overflow_handler = overflow_handler;
10495 event->overflow_handler_context = context;
10496 } else if (is_write_backward(event)){
10497 event->overflow_handler = perf_event_output_backward;
10498 event->overflow_handler_context = NULL;
10499 } else {
10500 event->overflow_handler = perf_event_output_forward;
10501 event->overflow_handler_context = NULL;
10502 }
10503
10504 perf_event__state_init(event);
10505
10506 pmu = NULL;
10507
10508 hwc = &event->hw;
10509 hwc->sample_period = attr->sample_period;
10510 if (attr->freq && attr->sample_freq)
10511 hwc->sample_period = 1;
10512 hwc->last_period = hwc->sample_period;
10513
10514 local64_set(&hwc->period_left, hwc->sample_period);
10515
10516 /*
10517 * We currently do not support PERF_SAMPLE_READ on inherited events.
10518 * See perf_output_read().
10519 */
10520 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
10521 goto err_ns;
10522
10523 if (!has_branch_stack(event))
10524 event->attr.branch_sample_type = 0;
10525
10526 if (cgroup_fd != -1) {
10527 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
10528 if (err)
10529 goto err_ns;
10530 }
10531
10532 pmu = perf_init_event(event);
10533 if (IS_ERR(pmu)) {
10534 err = PTR_ERR(pmu);
10535 goto err_ns;
10536 }
10537
10538 /*
10539 * Disallow uncore-cgroup events, they don't make sense as the cgroup will
10540 * be different on other CPUs in the uncore mask.
10541 */
10542 if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) {
10543 err = -EINVAL;
10544 goto err_pmu;
10545 }
10546
10547 if (event->attr.aux_output &&
10548 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
10549 err = -EOPNOTSUPP;
10550 goto err_pmu;
10551 }
10552
10553 err = exclusive_event_init(event);
10554 if (err)
10555 goto err_pmu;
10556
10557 if (has_addr_filter(event)) {
10558 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
10559 sizeof(struct perf_addr_filter_range),
10560 GFP_KERNEL);
10561 if (!event->addr_filter_ranges) {
10562 err = -ENOMEM;
10563 goto err_per_task;
10564 }
10565
10566 /*
10567 * Clone the parent's vma offsets: they are valid until exec()
10568 * even if the mm is not shared with the parent.
10569 */
10570 if (event->parent) {
10571 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10572
10573 raw_spin_lock_irq(&ifh->lock);
10574 memcpy(event->addr_filter_ranges,
10575 event->parent->addr_filter_ranges,
10576 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
10577 raw_spin_unlock_irq(&ifh->lock);
10578 }
10579
10580 /* force hw sync on the address filters */
10581 event->addr_filters_gen = 1;
10582 }
10583
10584 if (!event->parent) {
10585 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
10586 err = get_callchain_buffers(attr->sample_max_stack);
10587 if (err)
10588 goto err_addr_filters;
10589 }
10590 }
10591
10592 /* symmetric to unaccount_event() in _free_event() */
10593 account_event(event);
10594
10595 return event;
10596
10597err_addr_filters:
10598 kfree(event->addr_filter_ranges);
10599
10600err_per_task:
10601 exclusive_event_destroy(event);
10602
10603err_pmu:
10604 if (event->destroy)
10605 event->destroy(event);
10606 module_put(pmu->module);
10607err_ns:
10608 if (is_cgroup_event(event))
10609 perf_detach_cgroup(event);
10610 if (event->ns)
10611 put_pid_ns(event->ns);
10612 if (event->hw.target)
10613 put_task_struct(event->hw.target);
10614 kfree(event);
10615
10616 return ERR_PTR(err);
10617}
10618
10619static int perf_copy_attr(struct perf_event_attr __user *uattr,
10620 struct perf_event_attr *attr)
10621{
10622 u32 size;
10623 int ret;
10624
10625 /* Zero the full structure, so that a short copy will be nice. */
10626 memset(attr, 0, sizeof(*attr));
10627
10628 ret = get_user(size, &uattr->size);
10629 if (ret)
10630 return ret;
10631
10632 /* ABI compatibility quirk: */
10633 if (!size)
10634 size = PERF_ATTR_SIZE_VER0;
10635 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
10636 goto err_size;
10637
10638 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
10639 if (ret) {
10640 if (ret == -E2BIG)
10641 goto err_size;
10642 return ret;
10643 }
10644
10645 attr->size = size;
10646
10647 if (attr->__reserved_1 || attr->__reserved_2)
10648 return -EINVAL;
10649
10650 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
10651 return -EINVAL;
10652
10653 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
10654 return -EINVAL;
10655
10656 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
10657 u64 mask = attr->branch_sample_type;
10658
10659 /* only using defined bits */
10660 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
10661 return -EINVAL;
10662
10663 /* at least one branch bit must be set */
10664 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
10665 return -EINVAL;
10666
10667 /* propagate priv level, when not set for branch */
10668 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
10669
10670 /* exclude_kernel checked on syscall entry */
10671 if (!attr->exclude_kernel)
10672 mask |= PERF_SAMPLE_BRANCH_KERNEL;
10673
10674 if (!attr->exclude_user)
10675 mask |= PERF_SAMPLE_BRANCH_USER;
10676
10677 if (!attr->exclude_hv)
10678 mask |= PERF_SAMPLE_BRANCH_HV;
10679 /*
10680 * adjust user setting (for HW filter setup)
10681 */
10682 attr->branch_sample_type = mask;
10683 }
10684 /* privileged levels capture (kernel, hv): check permissions */
10685 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
10686 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10687 return -EACCES;
10688 }
10689
10690 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
10691 ret = perf_reg_validate(attr->sample_regs_user);
10692 if (ret)
10693 return ret;
10694 }
10695
10696 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
10697 if (!arch_perf_have_user_stack_dump())
10698 return -ENOSYS;
10699
10700 /*
10701 * We have __u32 type for the size, but so far
10702 * we can only use __u16 as maximum due to the
10703 * __u16 sample size limit.
10704 */
10705 if (attr->sample_stack_user >= USHRT_MAX)
10706 return -EINVAL;
10707 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
10708 return -EINVAL;
10709 }
10710
10711 if (!attr->sample_max_stack)
10712 attr->sample_max_stack = sysctl_perf_event_max_stack;
10713
10714 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
10715 ret = perf_reg_validate(attr->sample_regs_intr);
10716out:
10717 return ret;
10718
10719err_size:
10720 put_user(sizeof(*attr), &uattr->size);
10721 ret = -E2BIG;
10722 goto out;
10723}
10724
10725static int
10726perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
10727{
10728 struct ring_buffer *rb = NULL;
10729 int ret = -EINVAL;
10730
10731 if (!output_event)
10732 goto set;
10733
10734 /* don't allow circular references */
10735 if (event == output_event)
10736 goto out;
10737
10738 /*
10739 * Don't allow cross-cpu buffers
10740 */
10741 if (output_event->cpu != event->cpu)
10742 goto out;
10743
10744 /*
10745 * If its not a per-cpu rb, it must be the same task.
10746 */
10747 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
10748 goto out;
10749
10750 /*
10751 * Mixing clocks in the same buffer is trouble you don't need.
10752 */
10753 if (output_event->clock != event->clock)
10754 goto out;
10755
10756 /*
10757 * Either writing ring buffer from beginning or from end.
10758 * Mixing is not allowed.
10759 */
10760 if (is_write_backward(output_event) != is_write_backward(event))
10761 goto out;
10762
10763 /*
10764 * If both events generate aux data, they must be on the same PMU
10765 */
10766 if (has_aux(event) && has_aux(output_event) &&
10767 event->pmu != output_event->pmu)
10768 goto out;
10769
10770set:
10771 mutex_lock(&event->mmap_mutex);
10772 /* Can't redirect output if we've got an active mmap() */
10773 if (atomic_read(&event->mmap_count))
10774 goto unlock;
10775
10776 if (output_event) {
10777 /* get the rb we want to redirect to */
10778 rb = ring_buffer_get(output_event);
10779 if (!rb)
10780 goto unlock;
10781 }
10782
10783 ring_buffer_attach(event, rb);
10784
10785 ret = 0;
10786unlock:
10787 mutex_unlock(&event->mmap_mutex);
10788
10789out:
10790 return ret;
10791}
10792
10793static void mutex_lock_double(struct mutex *a, struct mutex *b)
10794{
10795 if (b < a)
10796 swap(a, b);
10797
10798 mutex_lock(a);
10799 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
10800}
10801
10802static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
10803{
10804 bool nmi_safe = false;
10805
10806 switch (clk_id) {
10807 case CLOCK_MONOTONIC:
10808 event->clock = &ktime_get_mono_fast_ns;
10809 nmi_safe = true;
10810 break;
10811
10812 case CLOCK_MONOTONIC_RAW:
10813 event->clock = &ktime_get_raw_fast_ns;
10814 nmi_safe = true;
10815 break;
10816
10817 case CLOCK_REALTIME:
10818 event->clock = &ktime_get_real_ns;
10819 break;
10820
10821 case CLOCK_BOOTTIME:
10822 event->clock = &ktime_get_boottime_ns;
10823 break;
10824
10825 case CLOCK_TAI:
10826 event->clock = &ktime_get_clocktai_ns;
10827 break;
10828
10829 default:
10830 return -EINVAL;
10831 }
10832
10833 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
10834 return -EINVAL;
10835
10836 return 0;
10837}
10838
10839/*
10840 * Variation on perf_event_ctx_lock_nested(), except we take two context
10841 * mutexes.
10842 */
10843static struct perf_event_context *
10844__perf_event_ctx_lock_double(struct perf_event *group_leader,
10845 struct perf_event_context *ctx)
10846{
10847 struct perf_event_context *gctx;
10848
10849again:
10850 rcu_read_lock();
10851 gctx = READ_ONCE(group_leader->ctx);
10852 if (!refcount_inc_not_zero(&gctx->refcount)) {
10853 rcu_read_unlock();
10854 goto again;
10855 }
10856 rcu_read_unlock();
10857
10858 mutex_lock_double(&gctx->mutex, &ctx->mutex);
10859
10860 if (group_leader->ctx != gctx) {
10861 mutex_unlock(&ctx->mutex);
10862 mutex_unlock(&gctx->mutex);
10863 put_ctx(gctx);
10864 goto again;
10865 }
10866
10867 return gctx;
10868}
10869
10870/**
10871 * sys_perf_event_open - open a performance event, associate it to a task/cpu
10872 *
10873 * @attr_uptr: event_id type attributes for monitoring/sampling
10874 * @pid: target pid
10875 * @cpu: target cpu
10876 * @group_fd: group leader event fd
10877 */
10878SYSCALL_DEFINE5(perf_event_open,
10879 struct perf_event_attr __user *, attr_uptr,
10880 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
10881{
10882 struct perf_event *group_leader = NULL, *output_event = NULL;
10883 struct perf_event *event, *sibling;
10884 struct perf_event_attr attr;
10885 struct perf_event_context *ctx, *uninitialized_var(gctx);
10886 struct file *event_file = NULL;
10887 struct fd group = {NULL, 0};
10888 struct task_struct *task = NULL;
10889 struct pmu *pmu;
10890 int event_fd;
10891 int move_group = 0;
10892 int err;
10893 int f_flags = O_RDWR;
10894 int cgroup_fd = -1;
10895
10896 /* for future expandability... */
10897 if (flags & ~PERF_FLAG_ALL)
10898 return -EINVAL;
10899
10900 err = perf_copy_attr(attr_uptr, &attr);
10901 if (err)
10902 return err;
10903
10904 if (!attr.exclude_kernel) {
10905 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10906 return -EACCES;
10907 }
10908
10909 if (attr.namespaces) {
10910 if (!capable(CAP_SYS_ADMIN))
10911 return -EACCES;
10912 }
10913
10914 if (attr.freq) {
10915 if (attr.sample_freq > sysctl_perf_event_sample_rate)
10916 return -EINVAL;
10917 } else {
10918 if (attr.sample_period & (1ULL << 63))
10919 return -EINVAL;
10920 }
10921
10922 /* Only privileged users can get physical addresses */
10923 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
10924 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10925 return -EACCES;
10926
10927 err = security_locked_down(LOCKDOWN_PERF);
10928 if (err && (attr.sample_type & PERF_SAMPLE_REGS_INTR))
10929 /* REGS_INTR can leak data, lockdown must prevent this */
10930 return err;
10931
10932 err = 0;
10933
10934 /*
10935 * In cgroup mode, the pid argument is used to pass the fd
10936 * opened to the cgroup directory in cgroupfs. The cpu argument
10937 * designates the cpu on which to monitor threads from that
10938 * cgroup.
10939 */
10940 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
10941 return -EINVAL;
10942
10943 if (flags & PERF_FLAG_FD_CLOEXEC)
10944 f_flags |= O_CLOEXEC;
10945
10946 event_fd = get_unused_fd_flags(f_flags);
10947 if (event_fd < 0)
10948 return event_fd;
10949
10950 if (group_fd != -1) {
10951 err = perf_fget_light(group_fd, &group);
10952 if (err)
10953 goto err_fd;
10954 group_leader = group.file->private_data;
10955 if (flags & PERF_FLAG_FD_OUTPUT)
10956 output_event = group_leader;
10957 if (flags & PERF_FLAG_FD_NO_GROUP)
10958 group_leader = NULL;
10959 }
10960
10961 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
10962 task = find_lively_task_by_vpid(pid);
10963 if (IS_ERR(task)) {
10964 err = PTR_ERR(task);
10965 goto err_group_fd;
10966 }
10967 }
10968
10969 if (task && group_leader &&
10970 group_leader->attr.inherit != attr.inherit) {
10971 err = -EINVAL;
10972 goto err_task;
10973 }
10974
10975 if (task) {
10976 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
10977 if (err)
10978 goto err_task;
10979
10980 /*
10981 * Reuse ptrace permission checks for now.
10982 *
10983 * We must hold cred_guard_mutex across this and any potential
10984 * perf_install_in_context() call for this new event to
10985 * serialize against exec() altering our credentials (and the
10986 * perf_event_exit_task() that could imply).
10987 */
10988 err = -EACCES;
10989 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
10990 goto err_cred;
10991 }
10992
10993 if (flags & PERF_FLAG_PID_CGROUP)
10994 cgroup_fd = pid;
10995
10996 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10997 NULL, NULL, cgroup_fd);
10998 if (IS_ERR(event)) {
10999 err = PTR_ERR(event);
11000 goto err_cred;
11001 }
11002
11003 if (is_sampling_event(event)) {
11004 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
11005 err = -EOPNOTSUPP;
11006 goto err_alloc;
11007 }
11008 }
11009
11010 /*
11011 * Special case software events and allow them to be part of
11012 * any hardware group.
11013 */
11014 pmu = event->pmu;
11015
11016 if (attr.use_clockid) {
11017 err = perf_event_set_clock(event, attr.clockid);
11018 if (err)
11019 goto err_alloc;
11020 }
11021
11022 if (pmu->task_ctx_nr == perf_sw_context)
11023 event->event_caps |= PERF_EV_CAP_SOFTWARE;
11024
11025 if (group_leader) {
11026 if (is_software_event(event) &&
11027 !in_software_context(group_leader)) {
11028 /*
11029 * If the event is a sw event, but the group_leader
11030 * is on hw context.
11031 *
11032 * Allow the addition of software events to hw
11033 * groups, this is safe because software events
11034 * never fail to schedule.
11035 */
11036 pmu = group_leader->ctx->pmu;
11037 } else if (!is_software_event(event) &&
11038 is_software_event(group_leader) &&
11039 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11040 /*
11041 * In case the group is a pure software group, and we
11042 * try to add a hardware event, move the whole group to
11043 * the hardware context.
11044 */
11045 move_group = 1;
11046 }
11047 }
11048
11049 /*
11050 * Get the target context (task or percpu):
11051 */
11052 ctx = find_get_context(pmu, task, event);
11053 if (IS_ERR(ctx)) {
11054 err = PTR_ERR(ctx);
11055 goto err_alloc;
11056 }
11057
11058 /*
11059 * Look up the group leader (we will attach this event to it):
11060 */
11061 if (group_leader) {
11062 err = -EINVAL;
11063
11064 /*
11065 * Do not allow a recursive hierarchy (this new sibling
11066 * becoming part of another group-sibling):
11067 */
11068 if (group_leader->group_leader != group_leader)
11069 goto err_context;
11070
11071 /* All events in a group should have the same clock */
11072 if (group_leader->clock != event->clock)
11073 goto err_context;
11074
11075 /*
11076 * Make sure we're both events for the same CPU;
11077 * grouping events for different CPUs is broken; since
11078 * you can never concurrently schedule them anyhow.
11079 */
11080 if (group_leader->cpu != event->cpu)
11081 goto err_context;
11082
11083 /*
11084 * Make sure we're both on the same task, or both
11085 * per-CPU events.
11086 */
11087 if (group_leader->ctx->task != ctx->task)
11088 goto err_context;
11089
11090 /*
11091 * Do not allow to attach to a group in a different task
11092 * or CPU context. If we're moving SW events, we'll fix
11093 * this up later, so allow that.
11094 */
11095 if (!move_group && group_leader->ctx != ctx)
11096 goto err_context;
11097
11098 /*
11099 * Only a group leader can be exclusive or pinned
11100 */
11101 if (attr.exclusive || attr.pinned)
11102 goto err_context;
11103 }
11104
11105 if (output_event) {
11106 err = perf_event_set_output(event, output_event);
11107 if (err)
11108 goto err_context;
11109 }
11110
11111 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
11112 f_flags);
11113 if (IS_ERR(event_file)) {
11114 err = PTR_ERR(event_file);
11115 event_file = NULL;
11116 goto err_context;
11117 }
11118
11119 if (move_group) {
11120 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
11121
11122 if (gctx->task == TASK_TOMBSTONE) {
11123 err = -ESRCH;
11124 goto err_locked;
11125 }
11126
11127 /*
11128 * Check if we raced against another sys_perf_event_open() call
11129 * moving the software group underneath us.
11130 */
11131 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11132 /*
11133 * If someone moved the group out from under us, check
11134 * if this new event wound up on the same ctx, if so
11135 * its the regular !move_group case, otherwise fail.
11136 */
11137 if (gctx != ctx) {
11138 err = -EINVAL;
11139 goto err_locked;
11140 } else {
11141 perf_event_ctx_unlock(group_leader, gctx);
11142 move_group = 0;
11143 }
11144 }
11145
11146 /*
11147 * Failure to create exclusive events returns -EBUSY.
11148 */
11149 err = -EBUSY;
11150 if (!exclusive_event_installable(group_leader, ctx))
11151 goto err_locked;
11152
11153 for_each_sibling_event(sibling, group_leader) {
11154 if (!exclusive_event_installable(sibling, ctx))
11155 goto err_locked;
11156 }
11157 } else {
11158 mutex_lock(&ctx->mutex);
11159 }
11160
11161 if (ctx->task == TASK_TOMBSTONE) {
11162 err = -ESRCH;
11163 goto err_locked;
11164 }
11165
11166 if (!perf_event_validate_size(event)) {
11167 err = -E2BIG;
11168 goto err_locked;
11169 }
11170
11171 if (!task) {
11172 /*
11173 * Check if the @cpu we're creating an event for is online.
11174 *
11175 * We use the perf_cpu_context::ctx::mutex to serialize against
11176 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11177 */
11178 struct perf_cpu_context *cpuctx =
11179 container_of(ctx, struct perf_cpu_context, ctx);
11180
11181 if (!cpuctx->online) {
11182 err = -ENODEV;
11183 goto err_locked;
11184 }
11185 }
11186
11187 if (event->attr.aux_output && !perf_get_aux_event(event, group_leader))
11188 goto err_locked;
11189
11190 /*
11191 * Must be under the same ctx::mutex as perf_install_in_context(),
11192 * because we need to serialize with concurrent event creation.
11193 */
11194 if (!exclusive_event_installable(event, ctx)) {
11195 err = -EBUSY;
11196 goto err_locked;
11197 }
11198
11199 WARN_ON_ONCE(ctx->parent_ctx);
11200
11201 /*
11202 * This is the point on no return; we cannot fail hereafter. This is
11203 * where we start modifying current state.
11204 */
11205
11206 if (move_group) {
11207 /*
11208 * See perf_event_ctx_lock() for comments on the details
11209 * of swizzling perf_event::ctx.
11210 */
11211 perf_remove_from_context(group_leader, 0);
11212 put_ctx(gctx);
11213
11214 for_each_sibling_event(sibling, group_leader) {
11215 perf_remove_from_context(sibling, 0);
11216 put_ctx(gctx);
11217 }
11218
11219 /*
11220 * Wait for everybody to stop referencing the events through
11221 * the old lists, before installing it on new lists.
11222 */
11223 synchronize_rcu();
11224
11225 /*
11226 * Install the group siblings before the group leader.
11227 *
11228 * Because a group leader will try and install the entire group
11229 * (through the sibling list, which is still in-tact), we can
11230 * end up with siblings installed in the wrong context.
11231 *
11232 * By installing siblings first we NO-OP because they're not
11233 * reachable through the group lists.
11234 */
11235 for_each_sibling_event(sibling, group_leader) {
11236 perf_event__state_init(sibling);
11237 perf_install_in_context(ctx, sibling, sibling->cpu);
11238 get_ctx(ctx);
11239 }
11240
11241 /*
11242 * Removing from the context ends up with disabled
11243 * event. What we want here is event in the initial
11244 * startup state, ready to be add into new context.
11245 */
11246 perf_event__state_init(group_leader);
11247 perf_install_in_context(ctx, group_leader, group_leader->cpu);
11248 get_ctx(ctx);
11249 }
11250
11251 /*
11252 * Precalculate sample_data sizes; do while holding ctx::mutex such
11253 * that we're serialized against further additions and before
11254 * perf_install_in_context() which is the point the event is active and
11255 * can use these values.
11256 */
11257 perf_event__header_size(event);
11258 perf_event__id_header_size(event);
11259
11260 event->owner = current;
11261
11262 perf_install_in_context(ctx, event, event->cpu);
11263 perf_unpin_context(ctx);
11264
11265 if (move_group)
11266 perf_event_ctx_unlock(group_leader, gctx);
11267 mutex_unlock(&ctx->mutex);
11268
11269 if (task) {
11270 mutex_unlock(&task->signal->cred_guard_mutex);
11271 put_task_struct(task);
11272 }
11273
11274 mutex_lock(¤t->perf_event_mutex);
11275 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
11276 mutex_unlock(¤t->perf_event_mutex);
11277
11278 /*
11279 * Drop the reference on the group_event after placing the
11280 * new event on the sibling_list. This ensures destruction
11281 * of the group leader will find the pointer to itself in
11282 * perf_group_detach().
11283 */
11284 fdput(group);
11285 fd_install(event_fd, event_file);
11286 return event_fd;
11287
11288err_locked:
11289 if (move_group)
11290 perf_event_ctx_unlock(group_leader, gctx);
11291 mutex_unlock(&ctx->mutex);
11292/* err_file: */
11293 fput(event_file);
11294err_context:
11295 perf_unpin_context(ctx);
11296 put_ctx(ctx);
11297err_alloc:
11298 /*
11299 * If event_file is set, the fput() above will have called ->release()
11300 * and that will take care of freeing the event.
11301 */
11302 if (!event_file)
11303 free_event(event);
11304err_cred:
11305 if (task)
11306 mutex_unlock(&task->signal->cred_guard_mutex);
11307err_task:
11308 if (task)
11309 put_task_struct(task);
11310err_group_fd:
11311 fdput(group);
11312err_fd:
11313 put_unused_fd(event_fd);
11314 return err;
11315}
11316
11317/**
11318 * perf_event_create_kernel_counter
11319 *
11320 * @attr: attributes of the counter to create
11321 * @cpu: cpu in which the counter is bound
11322 * @task: task to profile (NULL for percpu)
11323 */
11324struct perf_event *
11325perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
11326 struct task_struct *task,
11327 perf_overflow_handler_t overflow_handler,
11328 void *context)
11329{
11330 struct perf_event_context *ctx;
11331 struct perf_event *event;
11332 int err;
11333
11334 /*
11335 * Grouping is not supported for kernel events, neither is 'AUX',
11336 * make sure the caller's intentions are adjusted.
11337 */
11338 if (attr->aux_output)
11339 return ERR_PTR(-EINVAL);
11340
11341 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
11342 overflow_handler, context, -1);
11343 if (IS_ERR(event)) {
11344 err = PTR_ERR(event);
11345 goto err;
11346 }
11347
11348 /* Mark owner so we could distinguish it from user events. */
11349 event->owner = TASK_TOMBSTONE;
11350
11351 /*
11352 * Get the target context (task or percpu):
11353 */
11354 ctx = find_get_context(event->pmu, task, event);
11355 if (IS_ERR(ctx)) {
11356 err = PTR_ERR(ctx);
11357 goto err_free;
11358 }
11359
11360 WARN_ON_ONCE(ctx->parent_ctx);
11361 mutex_lock(&ctx->mutex);
11362 if (ctx->task == TASK_TOMBSTONE) {
11363 err = -ESRCH;
11364 goto err_unlock;
11365 }
11366
11367 if (!task) {
11368 /*
11369 * Check if the @cpu we're creating an event for is online.
11370 *
11371 * We use the perf_cpu_context::ctx::mutex to serialize against
11372 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11373 */
11374 struct perf_cpu_context *cpuctx =
11375 container_of(ctx, struct perf_cpu_context, ctx);
11376 if (!cpuctx->online) {
11377 err = -ENODEV;
11378 goto err_unlock;
11379 }
11380 }
11381
11382 if (!exclusive_event_installable(event, ctx)) {
11383 err = -EBUSY;
11384 goto err_unlock;
11385 }
11386
11387 perf_install_in_context(ctx, event, event->cpu);
11388 perf_unpin_context(ctx);
11389 mutex_unlock(&ctx->mutex);
11390
11391 return event;
11392
11393err_unlock:
11394 mutex_unlock(&ctx->mutex);
11395 perf_unpin_context(ctx);
11396 put_ctx(ctx);
11397err_free:
11398 free_event(event);
11399err:
11400 return ERR_PTR(err);
11401}
11402EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
11403
11404void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
11405{
11406 struct perf_event_context *src_ctx;
11407 struct perf_event_context *dst_ctx;
11408 struct perf_event *event, *tmp;
11409 LIST_HEAD(events);
11410
11411 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
11412 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
11413
11414 /*
11415 * See perf_event_ctx_lock() for comments on the details
11416 * of swizzling perf_event::ctx.
11417 */
11418 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
11419 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
11420 event_entry) {
11421 perf_remove_from_context(event, 0);
11422 unaccount_event_cpu(event, src_cpu);
11423 put_ctx(src_ctx);
11424 list_add(&event->migrate_entry, &events);
11425 }
11426
11427 /*
11428 * Wait for the events to quiesce before re-instating them.
11429 */
11430 synchronize_rcu();
11431
11432 /*
11433 * Re-instate events in 2 passes.
11434 *
11435 * Skip over group leaders and only install siblings on this first
11436 * pass, siblings will not get enabled without a leader, however a
11437 * leader will enable its siblings, even if those are still on the old
11438 * context.
11439 */
11440 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11441 if (event->group_leader == event)
11442 continue;
11443
11444 list_del(&event->migrate_entry);
11445 if (event->state >= PERF_EVENT_STATE_OFF)
11446 event->state = PERF_EVENT_STATE_INACTIVE;
11447 account_event_cpu(event, dst_cpu);
11448 perf_install_in_context(dst_ctx, event, dst_cpu);
11449 get_ctx(dst_ctx);
11450 }
11451
11452 /*
11453 * Once all the siblings are setup properly, install the group leaders
11454 * to make it go.
11455 */
11456 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11457 list_del(&event->migrate_entry);
11458 if (event->state >= PERF_EVENT_STATE_OFF)
11459 event->state = PERF_EVENT_STATE_INACTIVE;
11460 account_event_cpu(event, dst_cpu);
11461 perf_install_in_context(dst_ctx, event, dst_cpu);
11462 get_ctx(dst_ctx);
11463 }
11464 mutex_unlock(&dst_ctx->mutex);
11465 mutex_unlock(&src_ctx->mutex);
11466}
11467EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
11468
11469static void sync_child_event(struct perf_event *child_event,
11470 struct task_struct *child)
11471{
11472 struct perf_event *parent_event = child_event->parent;
11473 u64 child_val;
11474
11475 if (child_event->attr.inherit_stat)
11476 perf_event_read_event(child_event, child);
11477
11478 child_val = perf_event_count(child_event);
11479
11480 /*
11481 * Add back the child's count to the parent's count:
11482 */
11483 atomic64_add(child_val, &parent_event->child_count);
11484 atomic64_add(child_event->total_time_enabled,
11485 &parent_event->child_total_time_enabled);
11486 atomic64_add(child_event->total_time_running,
11487 &parent_event->child_total_time_running);
11488}
11489
11490static void
11491perf_event_exit_event(struct perf_event *child_event,
11492 struct perf_event_context *child_ctx,
11493 struct task_struct *child)
11494{
11495 struct perf_event *parent_event = child_event->parent;
11496
11497 /*
11498 * Do not destroy the 'original' grouping; because of the context
11499 * switch optimization the original events could've ended up in a
11500 * random child task.
11501 *
11502 * If we were to destroy the original group, all group related
11503 * operations would cease to function properly after this random
11504 * child dies.
11505 *
11506 * Do destroy all inherited groups, we don't care about those
11507 * and being thorough is better.
11508 */
11509 raw_spin_lock_irq(&child_ctx->lock);
11510 WARN_ON_ONCE(child_ctx->is_active);
11511
11512 if (parent_event)
11513 perf_group_detach(child_event);
11514 list_del_event(child_event, child_ctx);
11515 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
11516 raw_spin_unlock_irq(&child_ctx->lock);
11517
11518 /*
11519 * Parent events are governed by their filedesc, retain them.
11520 */
11521 if (!parent_event) {
11522 perf_event_wakeup(child_event);
11523 return;
11524 }
11525 /*
11526 * Child events can be cleaned up.
11527 */
11528
11529 sync_child_event(child_event, child);
11530
11531 /*
11532 * Remove this event from the parent's list
11533 */
11534 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
11535 mutex_lock(&parent_event->child_mutex);
11536 list_del_init(&child_event->child_list);
11537 mutex_unlock(&parent_event->child_mutex);
11538
11539 /*
11540 * Kick perf_poll() for is_event_hup().
11541 */
11542 perf_event_wakeup(parent_event);
11543 free_event(child_event);
11544 put_event(parent_event);
11545}
11546
11547static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
11548{
11549 struct perf_event_context *child_ctx, *clone_ctx = NULL;
11550 struct perf_event *child_event, *next;
11551
11552 WARN_ON_ONCE(child != current);
11553
11554 child_ctx = perf_pin_task_context(child, ctxn);
11555 if (!child_ctx)
11556 return;
11557
11558 /*
11559 * In order to reduce the amount of tricky in ctx tear-down, we hold
11560 * ctx::mutex over the entire thing. This serializes against almost
11561 * everything that wants to access the ctx.
11562 *
11563 * The exception is sys_perf_event_open() /
11564 * perf_event_create_kernel_count() which does find_get_context()
11565 * without ctx::mutex (it cannot because of the move_group double mutex
11566 * lock thing). See the comments in perf_install_in_context().
11567 */
11568 mutex_lock(&child_ctx->mutex);
11569
11570 /*
11571 * In a single ctx::lock section, de-schedule the events and detach the
11572 * context from the task such that we cannot ever get it scheduled back
11573 * in.
11574 */
11575 raw_spin_lock_irq(&child_ctx->lock);
11576 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
11577
11578 /*
11579 * Now that the context is inactive, destroy the task <-> ctx relation
11580 * and mark the context dead.
11581 */
11582 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
11583 put_ctx(child_ctx); /* cannot be last */
11584 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
11585 put_task_struct(current); /* cannot be last */
11586
11587 clone_ctx = unclone_ctx(child_ctx);
11588 raw_spin_unlock_irq(&child_ctx->lock);
11589
11590 if (clone_ctx)
11591 put_ctx(clone_ctx);
11592
11593 /*
11594 * Report the task dead after unscheduling the events so that we
11595 * won't get any samples after PERF_RECORD_EXIT. We can however still
11596 * get a few PERF_RECORD_READ events.
11597 */
11598 perf_event_task(child, child_ctx, 0);
11599
11600 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
11601 perf_event_exit_event(child_event, child_ctx, child);
11602
11603 mutex_unlock(&child_ctx->mutex);
11604
11605 put_ctx(child_ctx);
11606}
11607
11608/*
11609 * When a child task exits, feed back event values to parent events.
11610 *
11611 * Can be called with cred_guard_mutex held when called from
11612 * install_exec_creds().
11613 */
11614void perf_event_exit_task(struct task_struct *child)
11615{
11616 struct perf_event *event, *tmp;
11617 int ctxn;
11618
11619 mutex_lock(&child->perf_event_mutex);
11620 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
11621 owner_entry) {
11622 list_del_init(&event->owner_entry);
11623
11624 /*
11625 * Ensure the list deletion is visible before we clear
11626 * the owner, closes a race against perf_release() where
11627 * we need to serialize on the owner->perf_event_mutex.
11628 */
11629 smp_store_release(&event->owner, NULL);
11630 }
11631 mutex_unlock(&child->perf_event_mutex);
11632
11633 for_each_task_context_nr(ctxn)
11634 perf_event_exit_task_context(child, ctxn);
11635
11636 /*
11637 * The perf_event_exit_task_context calls perf_event_task
11638 * with child's task_ctx, which generates EXIT events for
11639 * child contexts and sets child->perf_event_ctxp[] to NULL.
11640 * At this point we need to send EXIT events to cpu contexts.
11641 */
11642 perf_event_task(child, NULL, 0);
11643}
11644
11645static void perf_free_event(struct perf_event *event,
11646 struct perf_event_context *ctx)
11647{
11648 struct perf_event *parent = event->parent;
11649
11650 if (WARN_ON_ONCE(!parent))
11651 return;
11652
11653 mutex_lock(&parent->child_mutex);
11654 list_del_init(&event->child_list);
11655 mutex_unlock(&parent->child_mutex);
11656
11657 put_event(parent);
11658
11659 raw_spin_lock_irq(&ctx->lock);
11660 perf_group_detach(event);
11661 list_del_event(event, ctx);
11662 raw_spin_unlock_irq(&ctx->lock);
11663 free_event(event);
11664}
11665
11666/*
11667 * Free a context as created by inheritance by perf_event_init_task() below,
11668 * used by fork() in case of fail.
11669 *
11670 * Even though the task has never lived, the context and events have been
11671 * exposed through the child_list, so we must take care tearing it all down.
11672 */
11673void perf_event_free_task(struct task_struct *task)
11674{
11675 struct perf_event_context *ctx;
11676 struct perf_event *event, *tmp;
11677 int ctxn;
11678
11679 for_each_task_context_nr(ctxn) {
11680 ctx = task->perf_event_ctxp[ctxn];
11681 if (!ctx)
11682 continue;
11683
11684 mutex_lock(&ctx->mutex);
11685 raw_spin_lock_irq(&ctx->lock);
11686 /*
11687 * Destroy the task <-> ctx relation and mark the context dead.
11688 *
11689 * This is important because even though the task hasn't been
11690 * exposed yet the context has been (through child_list).
11691 */
11692 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
11693 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
11694 put_task_struct(task); /* cannot be last */
11695 raw_spin_unlock_irq(&ctx->lock);
11696
11697 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
11698 perf_free_event(event, ctx);
11699
11700 mutex_unlock(&ctx->mutex);
11701
11702 /*
11703 * perf_event_release_kernel() could've stolen some of our
11704 * child events and still have them on its free_list. In that
11705 * case we must wait for these events to have been freed (in
11706 * particular all their references to this task must've been
11707 * dropped).
11708 *
11709 * Without this copy_process() will unconditionally free this
11710 * task (irrespective of its reference count) and
11711 * _free_event()'s put_task_struct(event->hw.target) will be a
11712 * use-after-free.
11713 *
11714 * Wait for all events to drop their context reference.
11715 */
11716 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
11717 put_ctx(ctx); /* must be last */
11718 }
11719}
11720
11721void perf_event_delayed_put(struct task_struct *task)
11722{
11723 int ctxn;
11724
11725 for_each_task_context_nr(ctxn)
11726 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
11727}
11728
11729struct file *perf_event_get(unsigned int fd)
11730{
11731 struct file *file = fget(fd);
11732 if (!file)
11733 return ERR_PTR(-EBADF);
11734
11735 if (file->f_op != &perf_fops) {
11736 fput(file);
11737 return ERR_PTR(-EBADF);
11738 }
11739
11740 return file;
11741}
11742
11743const struct perf_event *perf_get_event(struct file *file)
11744{
11745 if (file->f_op != &perf_fops)
11746 return ERR_PTR(-EINVAL);
11747
11748 return file->private_data;
11749}
11750
11751const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
11752{
11753 if (!event)
11754 return ERR_PTR(-EINVAL);
11755
11756 return &event->attr;
11757}
11758
11759/*
11760 * Inherit an event from parent task to child task.
11761 *
11762 * Returns:
11763 * - valid pointer on success
11764 * - NULL for orphaned events
11765 * - IS_ERR() on error
11766 */
11767static struct perf_event *
11768inherit_event(struct perf_event *parent_event,
11769 struct task_struct *parent,
11770 struct perf_event_context *parent_ctx,
11771 struct task_struct *child,
11772 struct perf_event *group_leader,
11773 struct perf_event_context *child_ctx)
11774{
11775 enum perf_event_state parent_state = parent_event->state;
11776 struct perf_event *child_event;
11777 unsigned long flags;
11778
11779 /*
11780 * Instead of creating recursive hierarchies of events,
11781 * we link inherited events back to the original parent,
11782 * which has a filp for sure, which we use as the reference
11783 * count:
11784 */
11785 if (parent_event->parent)
11786 parent_event = parent_event->parent;
11787
11788 child_event = perf_event_alloc(&parent_event->attr,
11789 parent_event->cpu,
11790 child,
11791 group_leader, parent_event,
11792 NULL, NULL, -1);
11793 if (IS_ERR(child_event))
11794 return child_event;
11795
11796
11797 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
11798 !child_ctx->task_ctx_data) {
11799 struct pmu *pmu = child_event->pmu;
11800
11801 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
11802 GFP_KERNEL);
11803 if (!child_ctx->task_ctx_data) {
11804 free_event(child_event);
11805 return ERR_PTR(-ENOMEM);
11806 }
11807 }
11808
11809 /*
11810 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
11811 * must be under the same lock in order to serialize against
11812 * perf_event_release_kernel(), such that either we must observe
11813 * is_orphaned_event() or they will observe us on the child_list.
11814 */
11815 mutex_lock(&parent_event->child_mutex);
11816 if (is_orphaned_event(parent_event) ||
11817 !atomic_long_inc_not_zero(&parent_event->refcount)) {
11818 mutex_unlock(&parent_event->child_mutex);
11819 /* task_ctx_data is freed with child_ctx */
11820 free_event(child_event);
11821 return NULL;
11822 }
11823
11824 get_ctx(child_ctx);
11825
11826 /*
11827 * Make the child state follow the state of the parent event,
11828 * not its attr.disabled bit. We hold the parent's mutex,
11829 * so we won't race with perf_event_{en, dis}able_family.
11830 */
11831 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
11832 child_event->state = PERF_EVENT_STATE_INACTIVE;
11833 else
11834 child_event->state = PERF_EVENT_STATE_OFF;
11835
11836 if (parent_event->attr.freq) {
11837 u64 sample_period = parent_event->hw.sample_period;
11838 struct hw_perf_event *hwc = &child_event->hw;
11839
11840 hwc->sample_period = sample_period;
11841 hwc->last_period = sample_period;
11842
11843 local64_set(&hwc->period_left, sample_period);
11844 }
11845
11846 child_event->ctx = child_ctx;
11847 child_event->overflow_handler = parent_event->overflow_handler;
11848 child_event->overflow_handler_context
11849 = parent_event->overflow_handler_context;
11850
11851 /*
11852 * Precalculate sample_data sizes
11853 */
11854 perf_event__header_size(child_event);
11855 perf_event__id_header_size(child_event);
11856
11857 /*
11858 * Link it up in the child's context:
11859 */
11860 raw_spin_lock_irqsave(&child_ctx->lock, flags);
11861 add_event_to_ctx(child_event, child_ctx);
11862 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
11863
11864 /*
11865 * Link this into the parent event's child list
11866 */
11867 list_add_tail(&child_event->child_list, &parent_event->child_list);
11868 mutex_unlock(&parent_event->child_mutex);
11869
11870 return child_event;
11871}
11872
11873/*
11874 * Inherits an event group.
11875 *
11876 * This will quietly suppress orphaned events; !inherit_event() is not an error.
11877 * This matches with perf_event_release_kernel() removing all child events.
11878 *
11879 * Returns:
11880 * - 0 on success
11881 * - <0 on error
11882 */
11883static int inherit_group(struct perf_event *parent_event,
11884 struct task_struct *parent,
11885 struct perf_event_context *parent_ctx,
11886 struct task_struct *child,
11887 struct perf_event_context *child_ctx)
11888{
11889 struct perf_event *leader;
11890 struct perf_event *sub;
11891 struct perf_event *child_ctr;
11892
11893 leader = inherit_event(parent_event, parent, parent_ctx,
11894 child, NULL, child_ctx);
11895 if (IS_ERR(leader))
11896 return PTR_ERR(leader);
11897 /*
11898 * @leader can be NULL here because of is_orphaned_event(). In this
11899 * case inherit_event() will create individual events, similar to what
11900 * perf_group_detach() would do anyway.
11901 */
11902 for_each_sibling_event(sub, parent_event) {
11903 child_ctr = inherit_event(sub, parent, parent_ctx,
11904 child, leader, child_ctx);
11905 if (IS_ERR(child_ctr))
11906 return PTR_ERR(child_ctr);
11907
11908 if (sub->aux_event == parent_event && child_ctr &&
11909 !perf_get_aux_event(child_ctr, leader))
11910 return -EINVAL;
11911 }
11912 return 0;
11913}
11914
11915/*
11916 * Creates the child task context and tries to inherit the event-group.
11917 *
11918 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
11919 * inherited_all set when we 'fail' to inherit an orphaned event; this is
11920 * consistent with perf_event_release_kernel() removing all child events.
11921 *
11922 * Returns:
11923 * - 0 on success
11924 * - <0 on error
11925 */
11926static int
11927inherit_task_group(struct perf_event *event, struct task_struct *parent,
11928 struct perf_event_context *parent_ctx,
11929 struct task_struct *child, int ctxn,
11930 int *inherited_all)
11931{
11932 int ret;
11933 struct perf_event_context *child_ctx;
11934
11935 if (!event->attr.inherit) {
11936 *inherited_all = 0;
11937 return 0;
11938 }
11939
11940 child_ctx = child->perf_event_ctxp[ctxn];
11941 if (!child_ctx) {
11942 /*
11943 * This is executed from the parent task context, so
11944 * inherit events that have been marked for cloning.
11945 * First allocate and initialize a context for the
11946 * child.
11947 */
11948 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
11949 if (!child_ctx)
11950 return -ENOMEM;
11951
11952 child->perf_event_ctxp[ctxn] = child_ctx;
11953 }
11954
11955 ret = inherit_group(event, parent, parent_ctx,
11956 child, child_ctx);
11957
11958 if (ret)
11959 *inherited_all = 0;
11960
11961 return ret;
11962}
11963
11964/*
11965 * Initialize the perf_event context in task_struct
11966 */
11967static int perf_event_init_context(struct task_struct *child, int ctxn)
11968{
11969 struct perf_event_context *child_ctx, *parent_ctx;
11970 struct perf_event_context *cloned_ctx;
11971 struct perf_event *event;
11972 struct task_struct *parent = current;
11973 int inherited_all = 1;
11974 unsigned long flags;
11975 int ret = 0;
11976
11977 if (likely(!parent->perf_event_ctxp[ctxn]))
11978 return 0;
11979
11980 /*
11981 * If the parent's context is a clone, pin it so it won't get
11982 * swapped under us.
11983 */
11984 parent_ctx = perf_pin_task_context(parent, ctxn);
11985 if (!parent_ctx)
11986 return 0;
11987
11988 /*
11989 * No need to check if parent_ctx != NULL here; since we saw
11990 * it non-NULL earlier, the only reason for it to become NULL
11991 * is if we exit, and since we're currently in the middle of
11992 * a fork we can't be exiting at the same time.
11993 */
11994
11995 /*
11996 * Lock the parent list. No need to lock the child - not PID
11997 * hashed yet and not running, so nobody can access it.
11998 */
11999 mutex_lock(&parent_ctx->mutex);
12000
12001 /*
12002 * We dont have to disable NMIs - we are only looking at
12003 * the list, not manipulating it:
12004 */
12005 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
12006 ret = inherit_task_group(event, parent, parent_ctx,
12007 child, ctxn, &inherited_all);
12008 if (ret)
12009 goto out_unlock;
12010 }
12011
12012 /*
12013 * We can't hold ctx->lock when iterating the ->flexible_group list due
12014 * to allocations, but we need to prevent rotation because
12015 * rotate_ctx() will change the list from interrupt context.
12016 */
12017 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12018 parent_ctx->rotate_disable = 1;
12019 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12020
12021 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
12022 ret = inherit_task_group(event, parent, parent_ctx,
12023 child, ctxn, &inherited_all);
12024 if (ret)
12025 goto out_unlock;
12026 }
12027
12028 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12029 parent_ctx->rotate_disable = 0;
12030
12031 child_ctx = child->perf_event_ctxp[ctxn];
12032
12033 if (child_ctx && inherited_all) {
12034 /*
12035 * Mark the child context as a clone of the parent
12036 * context, or of whatever the parent is a clone of.
12037 *
12038 * Note that if the parent is a clone, the holding of
12039 * parent_ctx->lock avoids it from being uncloned.
12040 */
12041 cloned_ctx = parent_ctx->parent_ctx;
12042 if (cloned_ctx) {
12043 child_ctx->parent_ctx = cloned_ctx;
12044 child_ctx->parent_gen = parent_ctx->parent_gen;
12045 } else {
12046 child_ctx->parent_ctx = parent_ctx;
12047 child_ctx->parent_gen = parent_ctx->generation;
12048 }
12049 get_ctx(child_ctx->parent_ctx);
12050 }
12051
12052 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12053out_unlock:
12054 mutex_unlock(&parent_ctx->mutex);
12055
12056 perf_unpin_context(parent_ctx);
12057 put_ctx(parent_ctx);
12058
12059 return ret;
12060}
12061
12062/*
12063 * Initialize the perf_event context in task_struct
12064 */
12065int perf_event_init_task(struct task_struct *child)
12066{
12067 int ctxn, ret;
12068
12069 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
12070 mutex_init(&child->perf_event_mutex);
12071 INIT_LIST_HEAD(&child->perf_event_list);
12072
12073 for_each_task_context_nr(ctxn) {
12074 ret = perf_event_init_context(child, ctxn);
12075 if (ret) {
12076 perf_event_free_task(child);
12077 return ret;
12078 }
12079 }
12080
12081 return 0;
12082}
12083
12084static void __init perf_event_init_all_cpus(void)
12085{
12086 struct swevent_htable *swhash;
12087 int cpu;
12088
12089 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
12090
12091 for_each_possible_cpu(cpu) {
12092 swhash = &per_cpu(swevent_htable, cpu);
12093 mutex_init(&swhash->hlist_mutex);
12094 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
12095
12096 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
12097 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
12098
12099#ifdef CONFIG_CGROUP_PERF
12100 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
12101#endif
12102 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
12103 }
12104}
12105
12106static void perf_swevent_init_cpu(unsigned int cpu)
12107{
12108 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
12109
12110 mutex_lock(&swhash->hlist_mutex);
12111 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
12112 struct swevent_hlist *hlist;
12113
12114 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
12115 WARN_ON(!hlist);
12116 rcu_assign_pointer(swhash->swevent_hlist, hlist);
12117 }
12118 mutex_unlock(&swhash->hlist_mutex);
12119}
12120
12121#if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
12122static void __perf_event_exit_context(void *__info)
12123{
12124 struct perf_event_context *ctx = __info;
12125 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
12126 struct perf_event *event;
12127
12128 raw_spin_lock(&ctx->lock);
12129 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
12130 list_for_each_entry(event, &ctx->event_list, event_entry)
12131 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
12132 raw_spin_unlock(&ctx->lock);
12133}
12134
12135static void perf_event_exit_cpu_context(int cpu)
12136{
12137 struct perf_cpu_context *cpuctx;
12138 struct perf_event_context *ctx;
12139 struct pmu *pmu;
12140
12141 mutex_lock(&pmus_lock);
12142 list_for_each_entry(pmu, &pmus, entry) {
12143 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12144 ctx = &cpuctx->ctx;
12145
12146 mutex_lock(&ctx->mutex);
12147 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
12148 cpuctx->online = 0;
12149 mutex_unlock(&ctx->mutex);
12150 }
12151 cpumask_clear_cpu(cpu, perf_online_mask);
12152 mutex_unlock(&pmus_lock);
12153}
12154#else
12155
12156static void perf_event_exit_cpu_context(int cpu) { }
12157
12158#endif
12159
12160int perf_event_init_cpu(unsigned int cpu)
12161{
12162 struct perf_cpu_context *cpuctx;
12163 struct perf_event_context *ctx;
12164 struct pmu *pmu;
12165
12166 perf_swevent_init_cpu(cpu);
12167
12168 mutex_lock(&pmus_lock);
12169 cpumask_set_cpu(cpu, perf_online_mask);
12170 list_for_each_entry(pmu, &pmus, entry) {
12171 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12172 ctx = &cpuctx->ctx;
12173
12174 mutex_lock(&ctx->mutex);
12175 cpuctx->online = 1;
12176 mutex_unlock(&ctx->mutex);
12177 }
12178 mutex_unlock(&pmus_lock);
12179
12180 return 0;
12181}
12182
12183int perf_event_exit_cpu(unsigned int cpu)
12184{
12185 perf_event_exit_cpu_context(cpu);
12186 return 0;
12187}
12188
12189static int
12190perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
12191{
12192 int cpu;
12193
12194 for_each_online_cpu(cpu)
12195 perf_event_exit_cpu(cpu);
12196
12197 return NOTIFY_OK;
12198}
12199
12200/*
12201 * Run the perf reboot notifier at the very last possible moment so that
12202 * the generic watchdog code runs as long as possible.
12203 */
12204static struct notifier_block perf_reboot_notifier = {
12205 .notifier_call = perf_reboot,
12206 .priority = INT_MIN,
12207};
12208
12209void __init perf_event_init(void)
12210{
12211 int ret;
12212
12213 idr_init(&pmu_idr);
12214
12215 perf_event_init_all_cpus();
12216 init_srcu_struct(&pmus_srcu);
12217 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
12218 perf_pmu_register(&perf_cpu_clock, NULL, -1);
12219 perf_pmu_register(&perf_task_clock, NULL, -1);
12220 perf_tp_register();
12221 perf_event_init_cpu(smp_processor_id());
12222 register_reboot_notifier(&perf_reboot_notifier);
12223
12224 ret = init_hw_breakpoint();
12225 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
12226
12227 /*
12228 * Build time assertion that we keep the data_head at the intended
12229 * location. IOW, validation we got the __reserved[] size right.
12230 */
12231 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
12232 != 1024);
12233}
12234
12235ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
12236 char *page)
12237{
12238 struct perf_pmu_events_attr *pmu_attr =
12239 container_of(attr, struct perf_pmu_events_attr, attr);
12240
12241 if (pmu_attr->event_str)
12242 return sprintf(page, "%s\n", pmu_attr->event_str);
12243
12244 return 0;
12245}
12246EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
12247
12248static int __init perf_event_sysfs_init(void)
12249{
12250 struct pmu *pmu;
12251 int ret;
12252
12253 mutex_lock(&pmus_lock);
12254
12255 ret = bus_register(&pmu_bus);
12256 if (ret)
12257 goto unlock;
12258
12259 list_for_each_entry(pmu, &pmus, entry) {
12260 if (!pmu->name || pmu->type < 0)
12261 continue;
12262
12263 ret = pmu_dev_alloc(pmu);
12264 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
12265 }
12266 pmu_bus_running = 1;
12267 ret = 0;
12268
12269unlock:
12270 mutex_unlock(&pmus_lock);
12271
12272 return ret;
12273}
12274device_initcall(perf_event_sysfs_init);
12275
12276#ifdef CONFIG_CGROUP_PERF
12277static struct cgroup_subsys_state *
12278perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
12279{
12280 struct perf_cgroup *jc;
12281
12282 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
12283 if (!jc)
12284 return ERR_PTR(-ENOMEM);
12285
12286 jc->info = alloc_percpu(struct perf_cgroup_info);
12287 if (!jc->info) {
12288 kfree(jc);
12289 return ERR_PTR(-ENOMEM);
12290 }
12291
12292 return &jc->css;
12293}
12294
12295static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
12296{
12297 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
12298
12299 free_percpu(jc->info);
12300 kfree(jc);
12301}
12302
12303static int __perf_cgroup_move(void *info)
12304{
12305 struct task_struct *task = info;
12306 rcu_read_lock();
12307 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
12308 rcu_read_unlock();
12309 return 0;
12310}
12311
12312static void perf_cgroup_attach(struct cgroup_taskset *tset)
12313{
12314 struct task_struct *task;
12315 struct cgroup_subsys_state *css;
12316
12317 cgroup_taskset_for_each(task, css, tset)
12318 task_function_call(task, __perf_cgroup_move, task);
12319}
12320
12321struct cgroup_subsys perf_event_cgrp_subsys = {
12322 .css_alloc = perf_cgroup_css_alloc,
12323 .css_free = perf_cgroup_css_free,
12324 .attach = perf_cgroup_attach,
12325 /*
12326 * Implicitly enable on dfl hierarchy so that perf events can
12327 * always be filtered by cgroup2 path as long as perf_event
12328 * controller is not mounted on a legacy hierarchy.
12329 */
12330 .implicit_on_dfl = true,
12331 .threaded = true,
12332};
12333#endif /* CONFIG_CGROUP_PERF */
1/*
2 * Performance events core code:
3 *
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
8 *
9 * For licensing details see kernel-base/COPYING
10 */
11
12#include <linux/fs.h>
13#include <linux/mm.h>
14#include <linux/cpu.h>
15#include <linux/smp.h>
16#include <linux/idr.h>
17#include <linux/file.h>
18#include <linux/poll.h>
19#include <linux/slab.h>
20#include <linux/hash.h>
21#include <linux/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/vmalloc.h>
29#include <linux/hardirq.h>
30#include <linux/rculist.h>
31#include <linux/uaccess.h>
32#include <linux/syscalls.h>
33#include <linux/anon_inodes.h>
34#include <linux/kernel_stat.h>
35#include <linux/perf_event.h>
36#include <linux/ftrace_event.h>
37#include <linux/hw_breakpoint.h>
38
39#include "internal.h"
40
41#include <asm/irq_regs.h>
42
43struct remote_function_call {
44 struct task_struct *p;
45 int (*func)(void *info);
46 void *info;
47 int ret;
48};
49
50static void remote_function(void *data)
51{
52 struct remote_function_call *tfc = data;
53 struct task_struct *p = tfc->p;
54
55 if (p) {
56 tfc->ret = -EAGAIN;
57 if (task_cpu(p) != smp_processor_id() || !task_curr(p))
58 return;
59 }
60
61 tfc->ret = tfc->func(tfc->info);
62}
63
64/**
65 * task_function_call - call a function on the cpu on which a task runs
66 * @p: the task to evaluate
67 * @func: the function to be called
68 * @info: the function call argument
69 *
70 * Calls the function @func when the task is currently running. This might
71 * be on the current CPU, which just calls the function directly
72 *
73 * returns: @func return value, or
74 * -ESRCH - when the process isn't running
75 * -EAGAIN - when the process moved away
76 */
77static int
78task_function_call(struct task_struct *p, int (*func) (void *info), void *info)
79{
80 struct remote_function_call data = {
81 .p = p,
82 .func = func,
83 .info = info,
84 .ret = -ESRCH, /* No such (running) process */
85 };
86
87 if (task_curr(p))
88 smp_call_function_single(task_cpu(p), remote_function, &data, 1);
89
90 return data.ret;
91}
92
93/**
94 * cpu_function_call - call a function on the cpu
95 * @func: the function to be called
96 * @info: the function call argument
97 *
98 * Calls the function @func on the remote cpu.
99 *
100 * returns: @func return value or -ENXIO when the cpu is offline
101 */
102static int cpu_function_call(int cpu, int (*func) (void *info), void *info)
103{
104 struct remote_function_call data = {
105 .p = NULL,
106 .func = func,
107 .info = info,
108 .ret = -ENXIO, /* No such CPU */
109 };
110
111 smp_call_function_single(cpu, remote_function, &data, 1);
112
113 return data.ret;
114}
115
116#define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
117 PERF_FLAG_FD_OUTPUT |\
118 PERF_FLAG_PID_CGROUP)
119
120enum event_type_t {
121 EVENT_FLEXIBLE = 0x1,
122 EVENT_PINNED = 0x2,
123 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
124};
125
126/*
127 * perf_sched_events : >0 events exist
128 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
129 */
130struct jump_label_key perf_sched_events __read_mostly;
131static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
132
133static atomic_t nr_mmap_events __read_mostly;
134static atomic_t nr_comm_events __read_mostly;
135static atomic_t nr_task_events __read_mostly;
136
137static LIST_HEAD(pmus);
138static DEFINE_MUTEX(pmus_lock);
139static struct srcu_struct pmus_srcu;
140
141/*
142 * perf event paranoia level:
143 * -1 - not paranoid at all
144 * 0 - disallow raw tracepoint access for unpriv
145 * 1 - disallow cpu events for unpriv
146 * 2 - disallow kernel profiling for unpriv
147 */
148int sysctl_perf_event_paranoid __read_mostly = 1;
149
150/* Minimum for 512 kiB + 1 user control page */
151int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
152
153/*
154 * max perf event sample rate
155 */
156#define DEFAULT_MAX_SAMPLE_RATE 100000
157int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
158static int max_samples_per_tick __read_mostly =
159 DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
160
161int perf_proc_update_handler(struct ctl_table *table, int write,
162 void __user *buffer, size_t *lenp,
163 loff_t *ppos)
164{
165 int ret = proc_dointvec(table, write, buffer, lenp, ppos);
166
167 if (ret || !write)
168 return ret;
169
170 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
171
172 return 0;
173}
174
175static atomic64_t perf_event_id;
176
177static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
178 enum event_type_t event_type);
179
180static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
181 enum event_type_t event_type,
182 struct task_struct *task);
183
184static void update_context_time(struct perf_event_context *ctx);
185static u64 perf_event_time(struct perf_event *event);
186
187void __weak perf_event_print_debug(void) { }
188
189extern __weak const char *perf_pmu_name(void)
190{
191 return "pmu";
192}
193
194static inline u64 perf_clock(void)
195{
196 return local_clock();
197}
198
199static inline struct perf_cpu_context *
200__get_cpu_context(struct perf_event_context *ctx)
201{
202 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
203}
204
205static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
206 struct perf_event_context *ctx)
207{
208 raw_spin_lock(&cpuctx->ctx.lock);
209 if (ctx)
210 raw_spin_lock(&ctx->lock);
211}
212
213static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
214 struct perf_event_context *ctx)
215{
216 if (ctx)
217 raw_spin_unlock(&ctx->lock);
218 raw_spin_unlock(&cpuctx->ctx.lock);
219}
220
221#ifdef CONFIG_CGROUP_PERF
222
223/*
224 * Must ensure cgroup is pinned (css_get) before calling
225 * this function. In other words, we cannot call this function
226 * if there is no cgroup event for the current CPU context.
227 */
228static inline struct perf_cgroup *
229perf_cgroup_from_task(struct task_struct *task)
230{
231 return container_of(task_subsys_state(task, perf_subsys_id),
232 struct perf_cgroup, css);
233}
234
235static inline bool
236perf_cgroup_match(struct perf_event *event)
237{
238 struct perf_event_context *ctx = event->ctx;
239 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
240
241 return !event->cgrp || event->cgrp == cpuctx->cgrp;
242}
243
244static inline void perf_get_cgroup(struct perf_event *event)
245{
246 css_get(&event->cgrp->css);
247}
248
249static inline void perf_put_cgroup(struct perf_event *event)
250{
251 css_put(&event->cgrp->css);
252}
253
254static inline void perf_detach_cgroup(struct perf_event *event)
255{
256 perf_put_cgroup(event);
257 event->cgrp = NULL;
258}
259
260static inline int is_cgroup_event(struct perf_event *event)
261{
262 return event->cgrp != NULL;
263}
264
265static inline u64 perf_cgroup_event_time(struct perf_event *event)
266{
267 struct perf_cgroup_info *t;
268
269 t = per_cpu_ptr(event->cgrp->info, event->cpu);
270 return t->time;
271}
272
273static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
274{
275 struct perf_cgroup_info *info;
276 u64 now;
277
278 now = perf_clock();
279
280 info = this_cpu_ptr(cgrp->info);
281
282 info->time += now - info->timestamp;
283 info->timestamp = now;
284}
285
286static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
287{
288 struct perf_cgroup *cgrp_out = cpuctx->cgrp;
289 if (cgrp_out)
290 __update_cgrp_time(cgrp_out);
291}
292
293static inline void update_cgrp_time_from_event(struct perf_event *event)
294{
295 struct perf_cgroup *cgrp;
296
297 /*
298 * ensure we access cgroup data only when needed and
299 * when we know the cgroup is pinned (css_get)
300 */
301 if (!is_cgroup_event(event))
302 return;
303
304 cgrp = perf_cgroup_from_task(current);
305 /*
306 * Do not update time when cgroup is not active
307 */
308 if (cgrp == event->cgrp)
309 __update_cgrp_time(event->cgrp);
310}
311
312static inline void
313perf_cgroup_set_timestamp(struct task_struct *task,
314 struct perf_event_context *ctx)
315{
316 struct perf_cgroup *cgrp;
317 struct perf_cgroup_info *info;
318
319 /*
320 * ctx->lock held by caller
321 * ensure we do not access cgroup data
322 * unless we have the cgroup pinned (css_get)
323 */
324 if (!task || !ctx->nr_cgroups)
325 return;
326
327 cgrp = perf_cgroup_from_task(task);
328 info = this_cpu_ptr(cgrp->info);
329 info->timestamp = ctx->timestamp;
330}
331
332#define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
333#define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
334
335/*
336 * reschedule events based on the cgroup constraint of task.
337 *
338 * mode SWOUT : schedule out everything
339 * mode SWIN : schedule in based on cgroup for next
340 */
341void perf_cgroup_switch(struct task_struct *task, int mode)
342{
343 struct perf_cpu_context *cpuctx;
344 struct pmu *pmu;
345 unsigned long flags;
346
347 /*
348 * disable interrupts to avoid geting nr_cgroup
349 * changes via __perf_event_disable(). Also
350 * avoids preemption.
351 */
352 local_irq_save(flags);
353
354 /*
355 * we reschedule only in the presence of cgroup
356 * constrained events.
357 */
358 rcu_read_lock();
359
360 list_for_each_entry_rcu(pmu, &pmus, entry) {
361 cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
362
363 /*
364 * perf_cgroup_events says at least one
365 * context on this CPU has cgroup events.
366 *
367 * ctx->nr_cgroups reports the number of cgroup
368 * events for a context.
369 */
370 if (cpuctx->ctx.nr_cgroups > 0) {
371 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
372 perf_pmu_disable(cpuctx->ctx.pmu);
373
374 if (mode & PERF_CGROUP_SWOUT) {
375 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
376 /*
377 * must not be done before ctxswout due
378 * to event_filter_match() in event_sched_out()
379 */
380 cpuctx->cgrp = NULL;
381 }
382
383 if (mode & PERF_CGROUP_SWIN) {
384 WARN_ON_ONCE(cpuctx->cgrp);
385 /* set cgrp before ctxsw in to
386 * allow event_filter_match() to not
387 * have to pass task around
388 */
389 cpuctx->cgrp = perf_cgroup_from_task(task);
390 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
391 }
392 perf_pmu_enable(cpuctx->ctx.pmu);
393 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
394 }
395 }
396
397 rcu_read_unlock();
398
399 local_irq_restore(flags);
400}
401
402static inline void perf_cgroup_sched_out(struct task_struct *task,
403 struct task_struct *next)
404{
405 struct perf_cgroup *cgrp1;
406 struct perf_cgroup *cgrp2 = NULL;
407
408 /*
409 * we come here when we know perf_cgroup_events > 0
410 */
411 cgrp1 = perf_cgroup_from_task(task);
412
413 /*
414 * next is NULL when called from perf_event_enable_on_exec()
415 * that will systematically cause a cgroup_switch()
416 */
417 if (next)
418 cgrp2 = perf_cgroup_from_task(next);
419
420 /*
421 * only schedule out current cgroup events if we know
422 * that we are switching to a different cgroup. Otherwise,
423 * do no touch the cgroup events.
424 */
425 if (cgrp1 != cgrp2)
426 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
427}
428
429static inline void perf_cgroup_sched_in(struct task_struct *prev,
430 struct task_struct *task)
431{
432 struct perf_cgroup *cgrp1;
433 struct perf_cgroup *cgrp2 = NULL;
434
435 /*
436 * we come here when we know perf_cgroup_events > 0
437 */
438 cgrp1 = perf_cgroup_from_task(task);
439
440 /* prev can never be NULL */
441 cgrp2 = perf_cgroup_from_task(prev);
442
443 /*
444 * only need to schedule in cgroup events if we are changing
445 * cgroup during ctxsw. Cgroup events were not scheduled
446 * out of ctxsw out if that was not the case.
447 */
448 if (cgrp1 != cgrp2)
449 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
450}
451
452static inline int perf_cgroup_connect(int fd, struct perf_event *event,
453 struct perf_event_attr *attr,
454 struct perf_event *group_leader)
455{
456 struct perf_cgroup *cgrp;
457 struct cgroup_subsys_state *css;
458 struct file *file;
459 int ret = 0, fput_needed;
460
461 file = fget_light(fd, &fput_needed);
462 if (!file)
463 return -EBADF;
464
465 css = cgroup_css_from_dir(file, perf_subsys_id);
466 if (IS_ERR(css)) {
467 ret = PTR_ERR(css);
468 goto out;
469 }
470
471 cgrp = container_of(css, struct perf_cgroup, css);
472 event->cgrp = cgrp;
473
474 /* must be done before we fput() the file */
475 perf_get_cgroup(event);
476
477 /*
478 * all events in a group must monitor
479 * the same cgroup because a task belongs
480 * to only one perf cgroup at a time
481 */
482 if (group_leader && group_leader->cgrp != cgrp) {
483 perf_detach_cgroup(event);
484 ret = -EINVAL;
485 }
486out:
487 fput_light(file, fput_needed);
488 return ret;
489}
490
491static inline void
492perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
493{
494 struct perf_cgroup_info *t;
495 t = per_cpu_ptr(event->cgrp->info, event->cpu);
496 event->shadow_ctx_time = now - t->timestamp;
497}
498
499static inline void
500perf_cgroup_defer_enabled(struct perf_event *event)
501{
502 /*
503 * when the current task's perf cgroup does not match
504 * the event's, we need to remember to call the
505 * perf_mark_enable() function the first time a task with
506 * a matching perf cgroup is scheduled in.
507 */
508 if (is_cgroup_event(event) && !perf_cgroup_match(event))
509 event->cgrp_defer_enabled = 1;
510}
511
512static inline void
513perf_cgroup_mark_enabled(struct perf_event *event,
514 struct perf_event_context *ctx)
515{
516 struct perf_event *sub;
517 u64 tstamp = perf_event_time(event);
518
519 if (!event->cgrp_defer_enabled)
520 return;
521
522 event->cgrp_defer_enabled = 0;
523
524 event->tstamp_enabled = tstamp - event->total_time_enabled;
525 list_for_each_entry(sub, &event->sibling_list, group_entry) {
526 if (sub->state >= PERF_EVENT_STATE_INACTIVE) {
527 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
528 sub->cgrp_defer_enabled = 0;
529 }
530 }
531}
532#else /* !CONFIG_CGROUP_PERF */
533
534static inline bool
535perf_cgroup_match(struct perf_event *event)
536{
537 return true;
538}
539
540static inline void perf_detach_cgroup(struct perf_event *event)
541{}
542
543static inline int is_cgroup_event(struct perf_event *event)
544{
545 return 0;
546}
547
548static inline u64 perf_cgroup_event_cgrp_time(struct perf_event *event)
549{
550 return 0;
551}
552
553static inline void update_cgrp_time_from_event(struct perf_event *event)
554{
555}
556
557static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
558{
559}
560
561static inline void perf_cgroup_sched_out(struct task_struct *task,
562 struct task_struct *next)
563{
564}
565
566static inline void perf_cgroup_sched_in(struct task_struct *prev,
567 struct task_struct *task)
568{
569}
570
571static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
572 struct perf_event_attr *attr,
573 struct perf_event *group_leader)
574{
575 return -EINVAL;
576}
577
578static inline void
579perf_cgroup_set_timestamp(struct task_struct *task,
580 struct perf_event_context *ctx)
581{
582}
583
584void
585perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
586{
587}
588
589static inline void
590perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
591{
592}
593
594static inline u64 perf_cgroup_event_time(struct perf_event *event)
595{
596 return 0;
597}
598
599static inline void
600perf_cgroup_defer_enabled(struct perf_event *event)
601{
602}
603
604static inline void
605perf_cgroup_mark_enabled(struct perf_event *event,
606 struct perf_event_context *ctx)
607{
608}
609#endif
610
611void perf_pmu_disable(struct pmu *pmu)
612{
613 int *count = this_cpu_ptr(pmu->pmu_disable_count);
614 if (!(*count)++)
615 pmu->pmu_disable(pmu);
616}
617
618void perf_pmu_enable(struct pmu *pmu)
619{
620 int *count = this_cpu_ptr(pmu->pmu_disable_count);
621 if (!--(*count))
622 pmu->pmu_enable(pmu);
623}
624
625static DEFINE_PER_CPU(struct list_head, rotation_list);
626
627/*
628 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
629 * because they're strictly cpu affine and rotate_start is called with IRQs
630 * disabled, while rotate_context is called from IRQ context.
631 */
632static void perf_pmu_rotate_start(struct pmu *pmu)
633{
634 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
635 struct list_head *head = &__get_cpu_var(rotation_list);
636
637 WARN_ON(!irqs_disabled());
638
639 if (list_empty(&cpuctx->rotation_list))
640 list_add(&cpuctx->rotation_list, head);
641}
642
643static void get_ctx(struct perf_event_context *ctx)
644{
645 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
646}
647
648static void put_ctx(struct perf_event_context *ctx)
649{
650 if (atomic_dec_and_test(&ctx->refcount)) {
651 if (ctx->parent_ctx)
652 put_ctx(ctx->parent_ctx);
653 if (ctx->task)
654 put_task_struct(ctx->task);
655 kfree_rcu(ctx, rcu_head);
656 }
657}
658
659static void unclone_ctx(struct perf_event_context *ctx)
660{
661 if (ctx->parent_ctx) {
662 put_ctx(ctx->parent_ctx);
663 ctx->parent_ctx = NULL;
664 }
665}
666
667static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
668{
669 /*
670 * only top level events have the pid namespace they were created in
671 */
672 if (event->parent)
673 event = event->parent;
674
675 return task_tgid_nr_ns(p, event->ns);
676}
677
678static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
679{
680 /*
681 * only top level events have the pid namespace they were created in
682 */
683 if (event->parent)
684 event = event->parent;
685
686 return task_pid_nr_ns(p, event->ns);
687}
688
689/*
690 * If we inherit events we want to return the parent event id
691 * to userspace.
692 */
693static u64 primary_event_id(struct perf_event *event)
694{
695 u64 id = event->id;
696
697 if (event->parent)
698 id = event->parent->id;
699
700 return id;
701}
702
703/*
704 * Get the perf_event_context for a task and lock it.
705 * This has to cope with with the fact that until it is locked,
706 * the context could get moved to another task.
707 */
708static struct perf_event_context *
709perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
710{
711 struct perf_event_context *ctx;
712
713 rcu_read_lock();
714retry:
715 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
716 if (ctx) {
717 /*
718 * If this context is a clone of another, it might
719 * get swapped for another underneath us by
720 * perf_event_task_sched_out, though the
721 * rcu_read_lock() protects us from any context
722 * getting freed. Lock the context and check if it
723 * got swapped before we could get the lock, and retry
724 * if so. If we locked the right context, then it
725 * can't get swapped on us any more.
726 */
727 raw_spin_lock_irqsave(&ctx->lock, *flags);
728 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
729 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
730 goto retry;
731 }
732
733 if (!atomic_inc_not_zero(&ctx->refcount)) {
734 raw_spin_unlock_irqrestore(&ctx->lock, *flags);
735 ctx = NULL;
736 }
737 }
738 rcu_read_unlock();
739 return ctx;
740}
741
742/*
743 * Get the context for a task and increment its pin_count so it
744 * can't get swapped to another task. This also increments its
745 * reference count so that the context can't get freed.
746 */
747static struct perf_event_context *
748perf_pin_task_context(struct task_struct *task, int ctxn)
749{
750 struct perf_event_context *ctx;
751 unsigned long flags;
752
753 ctx = perf_lock_task_context(task, ctxn, &flags);
754 if (ctx) {
755 ++ctx->pin_count;
756 raw_spin_unlock_irqrestore(&ctx->lock, flags);
757 }
758 return ctx;
759}
760
761static void perf_unpin_context(struct perf_event_context *ctx)
762{
763 unsigned long flags;
764
765 raw_spin_lock_irqsave(&ctx->lock, flags);
766 --ctx->pin_count;
767 raw_spin_unlock_irqrestore(&ctx->lock, flags);
768}
769
770/*
771 * Update the record of the current time in a context.
772 */
773static void update_context_time(struct perf_event_context *ctx)
774{
775 u64 now = perf_clock();
776
777 ctx->time += now - ctx->timestamp;
778 ctx->timestamp = now;
779}
780
781static u64 perf_event_time(struct perf_event *event)
782{
783 struct perf_event_context *ctx = event->ctx;
784
785 if (is_cgroup_event(event))
786 return perf_cgroup_event_time(event);
787
788 return ctx ? ctx->time : 0;
789}
790
791/*
792 * Update the total_time_enabled and total_time_running fields for a event.
793 * The caller of this function needs to hold the ctx->lock.
794 */
795static void update_event_times(struct perf_event *event)
796{
797 struct perf_event_context *ctx = event->ctx;
798 u64 run_end;
799
800 if (event->state < PERF_EVENT_STATE_INACTIVE ||
801 event->group_leader->state < PERF_EVENT_STATE_INACTIVE)
802 return;
803 /*
804 * in cgroup mode, time_enabled represents
805 * the time the event was enabled AND active
806 * tasks were in the monitored cgroup. This is
807 * independent of the activity of the context as
808 * there may be a mix of cgroup and non-cgroup events.
809 *
810 * That is why we treat cgroup events differently
811 * here.
812 */
813 if (is_cgroup_event(event))
814 run_end = perf_event_time(event);
815 else if (ctx->is_active)
816 run_end = ctx->time;
817 else
818 run_end = event->tstamp_stopped;
819
820 event->total_time_enabled = run_end - event->tstamp_enabled;
821
822 if (event->state == PERF_EVENT_STATE_INACTIVE)
823 run_end = event->tstamp_stopped;
824 else
825 run_end = perf_event_time(event);
826
827 event->total_time_running = run_end - event->tstamp_running;
828
829}
830
831/*
832 * Update total_time_enabled and total_time_running for all events in a group.
833 */
834static void update_group_times(struct perf_event *leader)
835{
836 struct perf_event *event;
837
838 update_event_times(leader);
839 list_for_each_entry(event, &leader->sibling_list, group_entry)
840 update_event_times(event);
841}
842
843static struct list_head *
844ctx_group_list(struct perf_event *event, struct perf_event_context *ctx)
845{
846 if (event->attr.pinned)
847 return &ctx->pinned_groups;
848 else
849 return &ctx->flexible_groups;
850}
851
852/*
853 * Add a event from the lists for its context.
854 * Must be called with ctx->mutex and ctx->lock held.
855 */
856static void
857list_add_event(struct perf_event *event, struct perf_event_context *ctx)
858{
859 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
860 event->attach_state |= PERF_ATTACH_CONTEXT;
861
862 /*
863 * If we're a stand alone event or group leader, we go to the context
864 * list, group events are kept attached to the group so that
865 * perf_group_detach can, at all times, locate all siblings.
866 */
867 if (event->group_leader == event) {
868 struct list_head *list;
869
870 if (is_software_event(event))
871 event->group_flags |= PERF_GROUP_SOFTWARE;
872
873 list = ctx_group_list(event, ctx);
874 list_add_tail(&event->group_entry, list);
875 }
876
877 if (is_cgroup_event(event))
878 ctx->nr_cgroups++;
879
880 list_add_rcu(&event->event_entry, &ctx->event_list);
881 if (!ctx->nr_events)
882 perf_pmu_rotate_start(ctx->pmu);
883 ctx->nr_events++;
884 if (event->attr.inherit_stat)
885 ctx->nr_stat++;
886}
887
888/*
889 * Called at perf_event creation and when events are attached/detached from a
890 * group.
891 */
892static void perf_event__read_size(struct perf_event *event)
893{
894 int entry = sizeof(u64); /* value */
895 int size = 0;
896 int nr = 1;
897
898 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
899 size += sizeof(u64);
900
901 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
902 size += sizeof(u64);
903
904 if (event->attr.read_format & PERF_FORMAT_ID)
905 entry += sizeof(u64);
906
907 if (event->attr.read_format & PERF_FORMAT_GROUP) {
908 nr += event->group_leader->nr_siblings;
909 size += sizeof(u64);
910 }
911
912 size += entry * nr;
913 event->read_size = size;
914}
915
916static void perf_event__header_size(struct perf_event *event)
917{
918 struct perf_sample_data *data;
919 u64 sample_type = event->attr.sample_type;
920 u16 size = 0;
921
922 perf_event__read_size(event);
923
924 if (sample_type & PERF_SAMPLE_IP)
925 size += sizeof(data->ip);
926
927 if (sample_type & PERF_SAMPLE_ADDR)
928 size += sizeof(data->addr);
929
930 if (sample_type & PERF_SAMPLE_PERIOD)
931 size += sizeof(data->period);
932
933 if (sample_type & PERF_SAMPLE_READ)
934 size += event->read_size;
935
936 event->header_size = size;
937}
938
939static void perf_event__id_header_size(struct perf_event *event)
940{
941 struct perf_sample_data *data;
942 u64 sample_type = event->attr.sample_type;
943 u16 size = 0;
944
945 if (sample_type & PERF_SAMPLE_TID)
946 size += sizeof(data->tid_entry);
947
948 if (sample_type & PERF_SAMPLE_TIME)
949 size += sizeof(data->time);
950
951 if (sample_type & PERF_SAMPLE_ID)
952 size += sizeof(data->id);
953
954 if (sample_type & PERF_SAMPLE_STREAM_ID)
955 size += sizeof(data->stream_id);
956
957 if (sample_type & PERF_SAMPLE_CPU)
958 size += sizeof(data->cpu_entry);
959
960 event->id_header_size = size;
961}
962
963static void perf_group_attach(struct perf_event *event)
964{
965 struct perf_event *group_leader = event->group_leader, *pos;
966
967 /*
968 * We can have double attach due to group movement in perf_event_open.
969 */
970 if (event->attach_state & PERF_ATTACH_GROUP)
971 return;
972
973 event->attach_state |= PERF_ATTACH_GROUP;
974
975 if (group_leader == event)
976 return;
977
978 if (group_leader->group_flags & PERF_GROUP_SOFTWARE &&
979 !is_software_event(event))
980 group_leader->group_flags &= ~PERF_GROUP_SOFTWARE;
981
982 list_add_tail(&event->group_entry, &group_leader->sibling_list);
983 group_leader->nr_siblings++;
984
985 perf_event__header_size(group_leader);
986
987 list_for_each_entry(pos, &group_leader->sibling_list, group_entry)
988 perf_event__header_size(pos);
989}
990
991/*
992 * Remove a event from the lists for its context.
993 * Must be called with ctx->mutex and ctx->lock held.
994 */
995static void
996list_del_event(struct perf_event *event, struct perf_event_context *ctx)
997{
998 struct perf_cpu_context *cpuctx;
999 /*
1000 * We can have double detach due to exit/hot-unplug + close.
1001 */
1002 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1003 return;
1004
1005 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1006
1007 if (is_cgroup_event(event)) {
1008 ctx->nr_cgroups--;
1009 cpuctx = __get_cpu_context(ctx);
1010 /*
1011 * if there are no more cgroup events
1012 * then cler cgrp to avoid stale pointer
1013 * in update_cgrp_time_from_cpuctx()
1014 */
1015 if (!ctx->nr_cgroups)
1016 cpuctx->cgrp = NULL;
1017 }
1018
1019 ctx->nr_events--;
1020 if (event->attr.inherit_stat)
1021 ctx->nr_stat--;
1022
1023 list_del_rcu(&event->event_entry);
1024
1025 if (event->group_leader == event)
1026 list_del_init(&event->group_entry);
1027
1028 update_group_times(event);
1029
1030 /*
1031 * If event was in error state, then keep it
1032 * that way, otherwise bogus counts will be
1033 * returned on read(). The only way to get out
1034 * of error state is by explicit re-enabling
1035 * of the event
1036 */
1037 if (event->state > PERF_EVENT_STATE_OFF)
1038 event->state = PERF_EVENT_STATE_OFF;
1039}
1040
1041static void perf_group_detach(struct perf_event *event)
1042{
1043 struct perf_event *sibling, *tmp;
1044 struct list_head *list = NULL;
1045
1046 /*
1047 * We can have double detach due to exit/hot-unplug + close.
1048 */
1049 if (!(event->attach_state & PERF_ATTACH_GROUP))
1050 return;
1051
1052 event->attach_state &= ~PERF_ATTACH_GROUP;
1053
1054 /*
1055 * If this is a sibling, remove it from its group.
1056 */
1057 if (event->group_leader != event) {
1058 list_del_init(&event->group_entry);
1059 event->group_leader->nr_siblings--;
1060 goto out;
1061 }
1062
1063 if (!list_empty(&event->group_entry))
1064 list = &event->group_entry;
1065
1066 /*
1067 * If this was a group event with sibling events then
1068 * upgrade the siblings to singleton events by adding them
1069 * to whatever list we are on.
1070 */
1071 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, group_entry) {
1072 if (list)
1073 list_move_tail(&sibling->group_entry, list);
1074 sibling->group_leader = sibling;
1075
1076 /* Inherit group flags from the previous leader */
1077 sibling->group_flags = event->group_flags;
1078 }
1079
1080out:
1081 perf_event__header_size(event->group_leader);
1082
1083 list_for_each_entry(tmp, &event->group_leader->sibling_list, group_entry)
1084 perf_event__header_size(tmp);
1085}
1086
1087static inline int
1088event_filter_match(struct perf_event *event)
1089{
1090 return (event->cpu == -1 || event->cpu == smp_processor_id())
1091 && perf_cgroup_match(event);
1092}
1093
1094static void
1095event_sched_out(struct perf_event *event,
1096 struct perf_cpu_context *cpuctx,
1097 struct perf_event_context *ctx)
1098{
1099 u64 tstamp = perf_event_time(event);
1100 u64 delta;
1101 /*
1102 * An event which could not be activated because of
1103 * filter mismatch still needs to have its timings
1104 * maintained, otherwise bogus information is return
1105 * via read() for time_enabled, time_running:
1106 */
1107 if (event->state == PERF_EVENT_STATE_INACTIVE
1108 && !event_filter_match(event)) {
1109 delta = tstamp - event->tstamp_stopped;
1110 event->tstamp_running += delta;
1111 event->tstamp_stopped = tstamp;
1112 }
1113
1114 if (event->state != PERF_EVENT_STATE_ACTIVE)
1115 return;
1116
1117 event->state = PERF_EVENT_STATE_INACTIVE;
1118 if (event->pending_disable) {
1119 event->pending_disable = 0;
1120 event->state = PERF_EVENT_STATE_OFF;
1121 }
1122 event->tstamp_stopped = tstamp;
1123 event->pmu->del(event, 0);
1124 event->oncpu = -1;
1125
1126 if (!is_software_event(event))
1127 cpuctx->active_oncpu--;
1128 ctx->nr_active--;
1129 if (event->attr.exclusive || !cpuctx->active_oncpu)
1130 cpuctx->exclusive = 0;
1131}
1132
1133static void
1134group_sched_out(struct perf_event *group_event,
1135 struct perf_cpu_context *cpuctx,
1136 struct perf_event_context *ctx)
1137{
1138 struct perf_event *event;
1139 int state = group_event->state;
1140
1141 event_sched_out(group_event, cpuctx, ctx);
1142
1143 /*
1144 * Schedule out siblings (if any):
1145 */
1146 list_for_each_entry(event, &group_event->sibling_list, group_entry)
1147 event_sched_out(event, cpuctx, ctx);
1148
1149 if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
1150 cpuctx->exclusive = 0;
1151}
1152
1153/*
1154 * Cross CPU call to remove a performance event
1155 *
1156 * We disable the event on the hardware level first. After that we
1157 * remove it from the context list.
1158 */
1159static int __perf_remove_from_context(void *info)
1160{
1161 struct perf_event *event = info;
1162 struct perf_event_context *ctx = event->ctx;
1163 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1164
1165 raw_spin_lock(&ctx->lock);
1166 event_sched_out(event, cpuctx, ctx);
1167 list_del_event(event, ctx);
1168 if (!ctx->nr_events && cpuctx->task_ctx == ctx) {
1169 ctx->is_active = 0;
1170 cpuctx->task_ctx = NULL;
1171 }
1172 raw_spin_unlock(&ctx->lock);
1173
1174 return 0;
1175}
1176
1177
1178/*
1179 * Remove the event from a task's (or a CPU's) list of events.
1180 *
1181 * CPU events are removed with a smp call. For task events we only
1182 * call when the task is on a CPU.
1183 *
1184 * If event->ctx is a cloned context, callers must make sure that
1185 * every task struct that event->ctx->task could possibly point to
1186 * remains valid. This is OK when called from perf_release since
1187 * that only calls us on the top-level context, which can't be a clone.
1188 * When called from perf_event_exit_task, it's OK because the
1189 * context has been detached from its task.
1190 */
1191static void perf_remove_from_context(struct perf_event *event)
1192{
1193 struct perf_event_context *ctx = event->ctx;
1194 struct task_struct *task = ctx->task;
1195
1196 lockdep_assert_held(&ctx->mutex);
1197
1198 if (!task) {
1199 /*
1200 * Per cpu events are removed via an smp call and
1201 * the removal is always successful.
1202 */
1203 cpu_function_call(event->cpu, __perf_remove_from_context, event);
1204 return;
1205 }
1206
1207retry:
1208 if (!task_function_call(task, __perf_remove_from_context, event))
1209 return;
1210
1211 raw_spin_lock_irq(&ctx->lock);
1212 /*
1213 * If we failed to find a running task, but find the context active now
1214 * that we've acquired the ctx->lock, retry.
1215 */
1216 if (ctx->is_active) {
1217 raw_spin_unlock_irq(&ctx->lock);
1218 goto retry;
1219 }
1220
1221 /*
1222 * Since the task isn't running, its safe to remove the event, us
1223 * holding the ctx->lock ensures the task won't get scheduled in.
1224 */
1225 list_del_event(event, ctx);
1226 raw_spin_unlock_irq(&ctx->lock);
1227}
1228
1229/*
1230 * Cross CPU call to disable a performance event
1231 */
1232static int __perf_event_disable(void *info)
1233{
1234 struct perf_event *event = info;
1235 struct perf_event_context *ctx = event->ctx;
1236 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1237
1238 /*
1239 * If this is a per-task event, need to check whether this
1240 * event's task is the current task on this cpu.
1241 *
1242 * Can trigger due to concurrent perf_event_context_sched_out()
1243 * flipping contexts around.
1244 */
1245 if (ctx->task && cpuctx->task_ctx != ctx)
1246 return -EINVAL;
1247
1248 raw_spin_lock(&ctx->lock);
1249
1250 /*
1251 * If the event is on, turn it off.
1252 * If it is in error state, leave it in error state.
1253 */
1254 if (event->state >= PERF_EVENT_STATE_INACTIVE) {
1255 update_context_time(ctx);
1256 update_cgrp_time_from_event(event);
1257 update_group_times(event);
1258 if (event == event->group_leader)
1259 group_sched_out(event, cpuctx, ctx);
1260 else
1261 event_sched_out(event, cpuctx, ctx);
1262 event->state = PERF_EVENT_STATE_OFF;
1263 }
1264
1265 raw_spin_unlock(&ctx->lock);
1266
1267 return 0;
1268}
1269
1270/*
1271 * Disable a event.
1272 *
1273 * If event->ctx is a cloned context, callers must make sure that
1274 * every task struct that event->ctx->task could possibly point to
1275 * remains valid. This condition is satisifed when called through
1276 * perf_event_for_each_child or perf_event_for_each because they
1277 * hold the top-level event's child_mutex, so any descendant that
1278 * goes to exit will block in sync_child_event.
1279 * When called from perf_pending_event it's OK because event->ctx
1280 * is the current context on this CPU and preemption is disabled,
1281 * hence we can't get into perf_event_task_sched_out for this context.
1282 */
1283void perf_event_disable(struct perf_event *event)
1284{
1285 struct perf_event_context *ctx = event->ctx;
1286 struct task_struct *task = ctx->task;
1287
1288 if (!task) {
1289 /*
1290 * Disable the event on the cpu that it's on
1291 */
1292 cpu_function_call(event->cpu, __perf_event_disable, event);
1293 return;
1294 }
1295
1296retry:
1297 if (!task_function_call(task, __perf_event_disable, event))
1298 return;
1299
1300 raw_spin_lock_irq(&ctx->lock);
1301 /*
1302 * If the event is still active, we need to retry the cross-call.
1303 */
1304 if (event->state == PERF_EVENT_STATE_ACTIVE) {
1305 raw_spin_unlock_irq(&ctx->lock);
1306 /*
1307 * Reload the task pointer, it might have been changed by
1308 * a concurrent perf_event_context_sched_out().
1309 */
1310 task = ctx->task;
1311 goto retry;
1312 }
1313
1314 /*
1315 * Since we have the lock this context can't be scheduled
1316 * in, so we can change the state safely.
1317 */
1318 if (event->state == PERF_EVENT_STATE_INACTIVE) {
1319 update_group_times(event);
1320 event->state = PERF_EVENT_STATE_OFF;
1321 }
1322 raw_spin_unlock_irq(&ctx->lock);
1323}
1324
1325static void perf_set_shadow_time(struct perf_event *event,
1326 struct perf_event_context *ctx,
1327 u64 tstamp)
1328{
1329 /*
1330 * use the correct time source for the time snapshot
1331 *
1332 * We could get by without this by leveraging the
1333 * fact that to get to this function, the caller
1334 * has most likely already called update_context_time()
1335 * and update_cgrp_time_xx() and thus both timestamp
1336 * are identical (or very close). Given that tstamp is,
1337 * already adjusted for cgroup, we could say that:
1338 * tstamp - ctx->timestamp
1339 * is equivalent to
1340 * tstamp - cgrp->timestamp.
1341 *
1342 * Then, in perf_output_read(), the calculation would
1343 * work with no changes because:
1344 * - event is guaranteed scheduled in
1345 * - no scheduled out in between
1346 * - thus the timestamp would be the same
1347 *
1348 * But this is a bit hairy.
1349 *
1350 * So instead, we have an explicit cgroup call to remain
1351 * within the time time source all along. We believe it
1352 * is cleaner and simpler to understand.
1353 */
1354 if (is_cgroup_event(event))
1355 perf_cgroup_set_shadow_time(event, tstamp);
1356 else
1357 event->shadow_ctx_time = tstamp - ctx->timestamp;
1358}
1359
1360#define MAX_INTERRUPTS (~0ULL)
1361
1362static void perf_log_throttle(struct perf_event *event, int enable);
1363
1364static int
1365event_sched_in(struct perf_event *event,
1366 struct perf_cpu_context *cpuctx,
1367 struct perf_event_context *ctx)
1368{
1369 u64 tstamp = perf_event_time(event);
1370
1371 if (event->state <= PERF_EVENT_STATE_OFF)
1372 return 0;
1373
1374 event->state = PERF_EVENT_STATE_ACTIVE;
1375 event->oncpu = smp_processor_id();
1376
1377 /*
1378 * Unthrottle events, since we scheduled we might have missed several
1379 * ticks already, also for a heavily scheduling task there is little
1380 * guarantee it'll get a tick in a timely manner.
1381 */
1382 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
1383 perf_log_throttle(event, 1);
1384 event->hw.interrupts = 0;
1385 }
1386
1387 /*
1388 * The new state must be visible before we turn it on in the hardware:
1389 */
1390 smp_wmb();
1391
1392 if (event->pmu->add(event, PERF_EF_START)) {
1393 event->state = PERF_EVENT_STATE_INACTIVE;
1394 event->oncpu = -1;
1395 return -EAGAIN;
1396 }
1397
1398 event->tstamp_running += tstamp - event->tstamp_stopped;
1399
1400 perf_set_shadow_time(event, ctx, tstamp);
1401
1402 if (!is_software_event(event))
1403 cpuctx->active_oncpu++;
1404 ctx->nr_active++;
1405
1406 if (event->attr.exclusive)
1407 cpuctx->exclusive = 1;
1408
1409 return 0;
1410}
1411
1412static int
1413group_sched_in(struct perf_event *group_event,
1414 struct perf_cpu_context *cpuctx,
1415 struct perf_event_context *ctx)
1416{
1417 struct perf_event *event, *partial_group = NULL;
1418 struct pmu *pmu = group_event->pmu;
1419 u64 now = ctx->time;
1420 bool simulate = false;
1421
1422 if (group_event->state == PERF_EVENT_STATE_OFF)
1423 return 0;
1424
1425 pmu->start_txn(pmu);
1426
1427 if (event_sched_in(group_event, cpuctx, ctx)) {
1428 pmu->cancel_txn(pmu);
1429 return -EAGAIN;
1430 }
1431
1432 /*
1433 * Schedule in siblings as one group (if any):
1434 */
1435 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1436 if (event_sched_in(event, cpuctx, ctx)) {
1437 partial_group = event;
1438 goto group_error;
1439 }
1440 }
1441
1442 if (!pmu->commit_txn(pmu))
1443 return 0;
1444
1445group_error:
1446 /*
1447 * Groups can be scheduled in as one unit only, so undo any
1448 * partial group before returning:
1449 * The events up to the failed event are scheduled out normally,
1450 * tstamp_stopped will be updated.
1451 *
1452 * The failed events and the remaining siblings need to have
1453 * their timings updated as if they had gone thru event_sched_in()
1454 * and event_sched_out(). This is required to get consistent timings
1455 * across the group. This also takes care of the case where the group
1456 * could never be scheduled by ensuring tstamp_stopped is set to mark
1457 * the time the event was actually stopped, such that time delta
1458 * calculation in update_event_times() is correct.
1459 */
1460 list_for_each_entry(event, &group_event->sibling_list, group_entry) {
1461 if (event == partial_group)
1462 simulate = true;
1463
1464 if (simulate) {
1465 event->tstamp_running += now - event->tstamp_stopped;
1466 event->tstamp_stopped = now;
1467 } else {
1468 event_sched_out(event, cpuctx, ctx);
1469 }
1470 }
1471 event_sched_out(group_event, cpuctx, ctx);
1472
1473 pmu->cancel_txn(pmu);
1474
1475 return -EAGAIN;
1476}
1477
1478/*
1479 * Work out whether we can put this event group on the CPU now.
1480 */
1481static int group_can_go_on(struct perf_event *event,
1482 struct perf_cpu_context *cpuctx,
1483 int can_add_hw)
1484{
1485 /*
1486 * Groups consisting entirely of software events can always go on.
1487 */
1488 if (event->group_flags & PERF_GROUP_SOFTWARE)
1489 return 1;
1490 /*
1491 * If an exclusive group is already on, no other hardware
1492 * events can go on.
1493 */
1494 if (cpuctx->exclusive)
1495 return 0;
1496 /*
1497 * If this group is exclusive and there are already
1498 * events on the CPU, it can't go on.
1499 */
1500 if (event->attr.exclusive && cpuctx->active_oncpu)
1501 return 0;
1502 /*
1503 * Otherwise, try to add it if all previous groups were able
1504 * to go on.
1505 */
1506 return can_add_hw;
1507}
1508
1509static void add_event_to_ctx(struct perf_event *event,
1510 struct perf_event_context *ctx)
1511{
1512 u64 tstamp = perf_event_time(event);
1513
1514 list_add_event(event, ctx);
1515 perf_group_attach(event);
1516 event->tstamp_enabled = tstamp;
1517 event->tstamp_running = tstamp;
1518 event->tstamp_stopped = tstamp;
1519}
1520
1521static void task_ctx_sched_out(struct perf_event_context *ctx);
1522static void
1523ctx_sched_in(struct perf_event_context *ctx,
1524 struct perf_cpu_context *cpuctx,
1525 enum event_type_t event_type,
1526 struct task_struct *task);
1527
1528static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
1529 struct perf_event_context *ctx,
1530 struct task_struct *task)
1531{
1532 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
1533 if (ctx)
1534 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
1535 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
1536 if (ctx)
1537 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
1538}
1539
1540/*
1541 * Cross CPU call to install and enable a performance event
1542 *
1543 * Must be called with ctx->mutex held
1544 */
1545static int __perf_install_in_context(void *info)
1546{
1547 struct perf_event *event = info;
1548 struct perf_event_context *ctx = event->ctx;
1549 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1550 struct perf_event_context *task_ctx = cpuctx->task_ctx;
1551 struct task_struct *task = current;
1552
1553 perf_ctx_lock(cpuctx, task_ctx);
1554 perf_pmu_disable(cpuctx->ctx.pmu);
1555
1556 /*
1557 * If there was an active task_ctx schedule it out.
1558 */
1559 if (task_ctx)
1560 task_ctx_sched_out(task_ctx);
1561
1562 /*
1563 * If the context we're installing events in is not the
1564 * active task_ctx, flip them.
1565 */
1566 if (ctx->task && task_ctx != ctx) {
1567 if (task_ctx)
1568 raw_spin_unlock(&task_ctx->lock);
1569 raw_spin_lock(&ctx->lock);
1570 task_ctx = ctx;
1571 }
1572
1573 if (task_ctx) {
1574 cpuctx->task_ctx = task_ctx;
1575 task = task_ctx->task;
1576 }
1577
1578 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
1579
1580 update_context_time(ctx);
1581 /*
1582 * update cgrp time only if current cgrp
1583 * matches event->cgrp. Must be done before
1584 * calling add_event_to_ctx()
1585 */
1586 update_cgrp_time_from_event(event);
1587
1588 add_event_to_ctx(event, ctx);
1589
1590 /*
1591 * Schedule everything back in
1592 */
1593 perf_event_sched_in(cpuctx, task_ctx, task);
1594
1595 perf_pmu_enable(cpuctx->ctx.pmu);
1596 perf_ctx_unlock(cpuctx, task_ctx);
1597
1598 return 0;
1599}
1600
1601/*
1602 * Attach a performance event to a context
1603 *
1604 * First we add the event to the list with the hardware enable bit
1605 * in event->hw_config cleared.
1606 *
1607 * If the event is attached to a task which is on a CPU we use a smp
1608 * call to enable it in the task context. The task might have been
1609 * scheduled away, but we check this in the smp call again.
1610 */
1611static void
1612perf_install_in_context(struct perf_event_context *ctx,
1613 struct perf_event *event,
1614 int cpu)
1615{
1616 struct task_struct *task = ctx->task;
1617
1618 lockdep_assert_held(&ctx->mutex);
1619
1620 event->ctx = ctx;
1621
1622 if (!task) {
1623 /*
1624 * Per cpu events are installed via an smp call and
1625 * the install is always successful.
1626 */
1627 cpu_function_call(cpu, __perf_install_in_context, event);
1628 return;
1629 }
1630
1631retry:
1632 if (!task_function_call(task, __perf_install_in_context, event))
1633 return;
1634
1635 raw_spin_lock_irq(&ctx->lock);
1636 /*
1637 * If we failed to find a running task, but find the context active now
1638 * that we've acquired the ctx->lock, retry.
1639 */
1640 if (ctx->is_active) {
1641 raw_spin_unlock_irq(&ctx->lock);
1642 goto retry;
1643 }
1644
1645 /*
1646 * Since the task isn't running, its safe to add the event, us holding
1647 * the ctx->lock ensures the task won't get scheduled in.
1648 */
1649 add_event_to_ctx(event, ctx);
1650 raw_spin_unlock_irq(&ctx->lock);
1651}
1652
1653/*
1654 * Put a event into inactive state and update time fields.
1655 * Enabling the leader of a group effectively enables all
1656 * the group members that aren't explicitly disabled, so we
1657 * have to update their ->tstamp_enabled also.
1658 * Note: this works for group members as well as group leaders
1659 * since the non-leader members' sibling_lists will be empty.
1660 */
1661static void __perf_event_mark_enabled(struct perf_event *event,
1662 struct perf_event_context *ctx)
1663{
1664 struct perf_event *sub;
1665 u64 tstamp = perf_event_time(event);
1666
1667 event->state = PERF_EVENT_STATE_INACTIVE;
1668 event->tstamp_enabled = tstamp - event->total_time_enabled;
1669 list_for_each_entry(sub, &event->sibling_list, group_entry) {
1670 if (sub->state >= PERF_EVENT_STATE_INACTIVE)
1671 sub->tstamp_enabled = tstamp - sub->total_time_enabled;
1672 }
1673}
1674
1675/*
1676 * Cross CPU call to enable a performance event
1677 */
1678static int __perf_event_enable(void *info)
1679{
1680 struct perf_event *event = info;
1681 struct perf_event_context *ctx = event->ctx;
1682 struct perf_event *leader = event->group_leader;
1683 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
1684 int err;
1685
1686 if (WARN_ON_ONCE(!ctx->is_active))
1687 return -EINVAL;
1688
1689 raw_spin_lock(&ctx->lock);
1690 update_context_time(ctx);
1691
1692 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1693 goto unlock;
1694
1695 /*
1696 * set current task's cgroup time reference point
1697 */
1698 perf_cgroup_set_timestamp(current, ctx);
1699
1700 __perf_event_mark_enabled(event, ctx);
1701
1702 if (!event_filter_match(event)) {
1703 if (is_cgroup_event(event))
1704 perf_cgroup_defer_enabled(event);
1705 goto unlock;
1706 }
1707
1708 /*
1709 * If the event is in a group and isn't the group leader,
1710 * then don't put it on unless the group is on.
1711 */
1712 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
1713 goto unlock;
1714
1715 if (!group_can_go_on(event, cpuctx, 1)) {
1716 err = -EEXIST;
1717 } else {
1718 if (event == leader)
1719 err = group_sched_in(event, cpuctx, ctx);
1720 else
1721 err = event_sched_in(event, cpuctx, ctx);
1722 }
1723
1724 if (err) {
1725 /*
1726 * If this event can't go on and it's part of a
1727 * group, then the whole group has to come off.
1728 */
1729 if (leader != event)
1730 group_sched_out(leader, cpuctx, ctx);
1731 if (leader->attr.pinned) {
1732 update_group_times(leader);
1733 leader->state = PERF_EVENT_STATE_ERROR;
1734 }
1735 }
1736
1737unlock:
1738 raw_spin_unlock(&ctx->lock);
1739
1740 return 0;
1741}
1742
1743/*
1744 * Enable a event.
1745 *
1746 * If event->ctx is a cloned context, callers must make sure that
1747 * every task struct that event->ctx->task could possibly point to
1748 * remains valid. This condition is satisfied when called through
1749 * perf_event_for_each_child or perf_event_for_each as described
1750 * for perf_event_disable.
1751 */
1752void perf_event_enable(struct perf_event *event)
1753{
1754 struct perf_event_context *ctx = event->ctx;
1755 struct task_struct *task = ctx->task;
1756
1757 if (!task) {
1758 /*
1759 * Enable the event on the cpu that it's on
1760 */
1761 cpu_function_call(event->cpu, __perf_event_enable, event);
1762 return;
1763 }
1764
1765 raw_spin_lock_irq(&ctx->lock);
1766 if (event->state >= PERF_EVENT_STATE_INACTIVE)
1767 goto out;
1768
1769 /*
1770 * If the event is in error state, clear that first.
1771 * That way, if we see the event in error state below, we
1772 * know that it has gone back into error state, as distinct
1773 * from the task having been scheduled away before the
1774 * cross-call arrived.
1775 */
1776 if (event->state == PERF_EVENT_STATE_ERROR)
1777 event->state = PERF_EVENT_STATE_OFF;
1778
1779retry:
1780 if (!ctx->is_active) {
1781 __perf_event_mark_enabled(event, ctx);
1782 goto out;
1783 }
1784
1785 raw_spin_unlock_irq(&ctx->lock);
1786
1787 if (!task_function_call(task, __perf_event_enable, event))
1788 return;
1789
1790 raw_spin_lock_irq(&ctx->lock);
1791
1792 /*
1793 * If the context is active and the event is still off,
1794 * we need to retry the cross-call.
1795 */
1796 if (ctx->is_active && event->state == PERF_EVENT_STATE_OFF) {
1797 /*
1798 * task could have been flipped by a concurrent
1799 * perf_event_context_sched_out()
1800 */
1801 task = ctx->task;
1802 goto retry;
1803 }
1804
1805out:
1806 raw_spin_unlock_irq(&ctx->lock);
1807}
1808
1809int perf_event_refresh(struct perf_event *event, int refresh)
1810{
1811 /*
1812 * not supported on inherited events
1813 */
1814 if (event->attr.inherit || !is_sampling_event(event))
1815 return -EINVAL;
1816
1817 atomic_add(refresh, &event->event_limit);
1818 perf_event_enable(event);
1819
1820 return 0;
1821}
1822EXPORT_SYMBOL_GPL(perf_event_refresh);
1823
1824static void ctx_sched_out(struct perf_event_context *ctx,
1825 struct perf_cpu_context *cpuctx,
1826 enum event_type_t event_type)
1827{
1828 struct perf_event *event;
1829 int is_active = ctx->is_active;
1830
1831 ctx->is_active &= ~event_type;
1832 if (likely(!ctx->nr_events))
1833 return;
1834
1835 update_context_time(ctx);
1836 update_cgrp_time_from_cpuctx(cpuctx);
1837 if (!ctx->nr_active)
1838 return;
1839
1840 perf_pmu_disable(ctx->pmu);
1841 if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
1842 list_for_each_entry(event, &ctx->pinned_groups, group_entry)
1843 group_sched_out(event, cpuctx, ctx);
1844 }
1845
1846 if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
1847 list_for_each_entry(event, &ctx->flexible_groups, group_entry)
1848 group_sched_out(event, cpuctx, ctx);
1849 }
1850 perf_pmu_enable(ctx->pmu);
1851}
1852
1853/*
1854 * Test whether two contexts are equivalent, i.e. whether they
1855 * have both been cloned from the same version of the same context
1856 * and they both have the same number of enabled events.
1857 * If the number of enabled events is the same, then the set
1858 * of enabled events should be the same, because these are both
1859 * inherited contexts, therefore we can't access individual events
1860 * in them directly with an fd; we can only enable/disable all
1861 * events via prctl, or enable/disable all events in a family
1862 * via ioctl, which will have the same effect on both contexts.
1863 */
1864static int context_equiv(struct perf_event_context *ctx1,
1865 struct perf_event_context *ctx2)
1866{
1867 return ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx
1868 && ctx1->parent_gen == ctx2->parent_gen
1869 && !ctx1->pin_count && !ctx2->pin_count;
1870}
1871
1872static void __perf_event_sync_stat(struct perf_event *event,
1873 struct perf_event *next_event)
1874{
1875 u64 value;
1876
1877 if (!event->attr.inherit_stat)
1878 return;
1879
1880 /*
1881 * Update the event value, we cannot use perf_event_read()
1882 * because we're in the middle of a context switch and have IRQs
1883 * disabled, which upsets smp_call_function_single(), however
1884 * we know the event must be on the current CPU, therefore we
1885 * don't need to use it.
1886 */
1887 switch (event->state) {
1888 case PERF_EVENT_STATE_ACTIVE:
1889 event->pmu->read(event);
1890 /* fall-through */
1891
1892 case PERF_EVENT_STATE_INACTIVE:
1893 update_event_times(event);
1894 break;
1895
1896 default:
1897 break;
1898 }
1899
1900 /*
1901 * In order to keep per-task stats reliable we need to flip the event
1902 * values when we flip the contexts.
1903 */
1904 value = local64_read(&next_event->count);
1905 value = local64_xchg(&event->count, value);
1906 local64_set(&next_event->count, value);
1907
1908 swap(event->total_time_enabled, next_event->total_time_enabled);
1909 swap(event->total_time_running, next_event->total_time_running);
1910
1911 /*
1912 * Since we swizzled the values, update the user visible data too.
1913 */
1914 perf_event_update_userpage(event);
1915 perf_event_update_userpage(next_event);
1916}
1917
1918#define list_next_entry(pos, member) \
1919 list_entry(pos->member.next, typeof(*pos), member)
1920
1921static void perf_event_sync_stat(struct perf_event_context *ctx,
1922 struct perf_event_context *next_ctx)
1923{
1924 struct perf_event *event, *next_event;
1925
1926 if (!ctx->nr_stat)
1927 return;
1928
1929 update_context_time(ctx);
1930
1931 event = list_first_entry(&ctx->event_list,
1932 struct perf_event, event_entry);
1933
1934 next_event = list_first_entry(&next_ctx->event_list,
1935 struct perf_event, event_entry);
1936
1937 while (&event->event_entry != &ctx->event_list &&
1938 &next_event->event_entry != &next_ctx->event_list) {
1939
1940 __perf_event_sync_stat(event, next_event);
1941
1942 event = list_next_entry(event, event_entry);
1943 next_event = list_next_entry(next_event, event_entry);
1944 }
1945}
1946
1947static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
1948 struct task_struct *next)
1949{
1950 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
1951 struct perf_event_context *next_ctx;
1952 struct perf_event_context *parent;
1953 struct perf_cpu_context *cpuctx;
1954 int do_switch = 1;
1955
1956 if (likely(!ctx))
1957 return;
1958
1959 cpuctx = __get_cpu_context(ctx);
1960 if (!cpuctx->task_ctx)
1961 return;
1962
1963 rcu_read_lock();
1964 parent = rcu_dereference(ctx->parent_ctx);
1965 next_ctx = next->perf_event_ctxp[ctxn];
1966 if (parent && next_ctx &&
1967 rcu_dereference(next_ctx->parent_ctx) == parent) {
1968 /*
1969 * Looks like the two contexts are clones, so we might be
1970 * able to optimize the context switch. We lock both
1971 * contexts and check that they are clones under the
1972 * lock (including re-checking that neither has been
1973 * uncloned in the meantime). It doesn't matter which
1974 * order we take the locks because no other cpu could
1975 * be trying to lock both of these tasks.
1976 */
1977 raw_spin_lock(&ctx->lock);
1978 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
1979 if (context_equiv(ctx, next_ctx)) {
1980 /*
1981 * XXX do we need a memory barrier of sorts
1982 * wrt to rcu_dereference() of perf_event_ctxp
1983 */
1984 task->perf_event_ctxp[ctxn] = next_ctx;
1985 next->perf_event_ctxp[ctxn] = ctx;
1986 ctx->task = next;
1987 next_ctx->task = task;
1988 do_switch = 0;
1989
1990 perf_event_sync_stat(ctx, next_ctx);
1991 }
1992 raw_spin_unlock(&next_ctx->lock);
1993 raw_spin_unlock(&ctx->lock);
1994 }
1995 rcu_read_unlock();
1996
1997 if (do_switch) {
1998 raw_spin_lock(&ctx->lock);
1999 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2000 cpuctx->task_ctx = NULL;
2001 raw_spin_unlock(&ctx->lock);
2002 }
2003}
2004
2005#define for_each_task_context_nr(ctxn) \
2006 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
2007
2008/*
2009 * Called from scheduler to remove the events of the current task,
2010 * with interrupts disabled.
2011 *
2012 * We stop each event and update the event value in event->count.
2013 *
2014 * This does not protect us against NMI, but disable()
2015 * sets the disabled bit in the control field of event _before_
2016 * accessing the event control register. If a NMI hits, then it will
2017 * not restart the event.
2018 */
2019void __perf_event_task_sched_out(struct task_struct *task,
2020 struct task_struct *next)
2021{
2022 int ctxn;
2023
2024 for_each_task_context_nr(ctxn)
2025 perf_event_context_sched_out(task, ctxn, next);
2026
2027 /*
2028 * if cgroup events exist on this CPU, then we need
2029 * to check if we have to switch out PMU state.
2030 * cgroup event are system-wide mode only
2031 */
2032 if (atomic_read(&__get_cpu_var(perf_cgroup_events)))
2033 perf_cgroup_sched_out(task, next);
2034}
2035
2036static void task_ctx_sched_out(struct perf_event_context *ctx)
2037{
2038 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2039
2040 if (!cpuctx->task_ctx)
2041 return;
2042
2043 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2044 return;
2045
2046 ctx_sched_out(ctx, cpuctx, EVENT_ALL);
2047 cpuctx->task_ctx = NULL;
2048}
2049
2050/*
2051 * Called with IRQs disabled
2052 */
2053static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
2054 enum event_type_t event_type)
2055{
2056 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
2057}
2058
2059static void
2060ctx_pinned_sched_in(struct perf_event_context *ctx,
2061 struct perf_cpu_context *cpuctx)
2062{
2063 struct perf_event *event;
2064
2065 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2066 if (event->state <= PERF_EVENT_STATE_OFF)
2067 continue;
2068 if (!event_filter_match(event))
2069 continue;
2070
2071 /* may need to reset tstamp_enabled */
2072 if (is_cgroup_event(event))
2073 perf_cgroup_mark_enabled(event, ctx);
2074
2075 if (group_can_go_on(event, cpuctx, 1))
2076 group_sched_in(event, cpuctx, ctx);
2077
2078 /*
2079 * If this pinned group hasn't been scheduled,
2080 * put it in error state.
2081 */
2082 if (event->state == PERF_EVENT_STATE_INACTIVE) {
2083 update_group_times(event);
2084 event->state = PERF_EVENT_STATE_ERROR;
2085 }
2086 }
2087}
2088
2089static void
2090ctx_flexible_sched_in(struct perf_event_context *ctx,
2091 struct perf_cpu_context *cpuctx)
2092{
2093 struct perf_event *event;
2094 int can_add_hw = 1;
2095
2096 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2097 /* Ignore events in OFF or ERROR state */
2098 if (event->state <= PERF_EVENT_STATE_OFF)
2099 continue;
2100 /*
2101 * Listen to the 'cpu' scheduling filter constraint
2102 * of events:
2103 */
2104 if (!event_filter_match(event))
2105 continue;
2106
2107 /* may need to reset tstamp_enabled */
2108 if (is_cgroup_event(event))
2109 perf_cgroup_mark_enabled(event, ctx);
2110
2111 if (group_can_go_on(event, cpuctx, can_add_hw)) {
2112 if (group_sched_in(event, cpuctx, ctx))
2113 can_add_hw = 0;
2114 }
2115 }
2116}
2117
2118static void
2119ctx_sched_in(struct perf_event_context *ctx,
2120 struct perf_cpu_context *cpuctx,
2121 enum event_type_t event_type,
2122 struct task_struct *task)
2123{
2124 u64 now;
2125 int is_active = ctx->is_active;
2126
2127 ctx->is_active |= event_type;
2128 if (likely(!ctx->nr_events))
2129 return;
2130
2131 now = perf_clock();
2132 ctx->timestamp = now;
2133 perf_cgroup_set_timestamp(task, ctx);
2134 /*
2135 * First go through the list and put on any pinned groups
2136 * in order to give them the best chance of going on.
2137 */
2138 if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
2139 ctx_pinned_sched_in(ctx, cpuctx);
2140
2141 /* Then walk through the lower prio flexible groups */
2142 if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
2143 ctx_flexible_sched_in(ctx, cpuctx);
2144}
2145
2146static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
2147 enum event_type_t event_type,
2148 struct task_struct *task)
2149{
2150 struct perf_event_context *ctx = &cpuctx->ctx;
2151
2152 ctx_sched_in(ctx, cpuctx, event_type, task);
2153}
2154
2155static void perf_event_context_sched_in(struct perf_event_context *ctx,
2156 struct task_struct *task)
2157{
2158 struct perf_cpu_context *cpuctx;
2159
2160 cpuctx = __get_cpu_context(ctx);
2161 if (cpuctx->task_ctx == ctx)
2162 return;
2163
2164 perf_ctx_lock(cpuctx, ctx);
2165 perf_pmu_disable(ctx->pmu);
2166 /*
2167 * We want to keep the following priority order:
2168 * cpu pinned (that don't need to move), task pinned,
2169 * cpu flexible, task flexible.
2170 */
2171 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2172
2173 perf_event_sched_in(cpuctx, ctx, task);
2174
2175 cpuctx->task_ctx = ctx;
2176
2177 perf_pmu_enable(ctx->pmu);
2178 perf_ctx_unlock(cpuctx, ctx);
2179
2180 /*
2181 * Since these rotations are per-cpu, we need to ensure the
2182 * cpu-context we got scheduled on is actually rotating.
2183 */
2184 perf_pmu_rotate_start(ctx->pmu);
2185}
2186
2187/*
2188 * Called from scheduler to add the events of the current task
2189 * with interrupts disabled.
2190 *
2191 * We restore the event value and then enable it.
2192 *
2193 * This does not protect us against NMI, but enable()
2194 * sets the enabled bit in the control field of event _before_
2195 * accessing the event control register. If a NMI hits, then it will
2196 * keep the event running.
2197 */
2198void __perf_event_task_sched_in(struct task_struct *prev,
2199 struct task_struct *task)
2200{
2201 struct perf_event_context *ctx;
2202 int ctxn;
2203
2204 for_each_task_context_nr(ctxn) {
2205 ctx = task->perf_event_ctxp[ctxn];
2206 if (likely(!ctx))
2207 continue;
2208
2209 perf_event_context_sched_in(ctx, task);
2210 }
2211 /*
2212 * if cgroup events exist on this CPU, then we need
2213 * to check if we have to switch in PMU state.
2214 * cgroup event are system-wide mode only
2215 */
2216 if (atomic_read(&__get_cpu_var(perf_cgroup_events)))
2217 perf_cgroup_sched_in(prev, task);
2218}
2219
2220static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
2221{
2222 u64 frequency = event->attr.sample_freq;
2223 u64 sec = NSEC_PER_SEC;
2224 u64 divisor, dividend;
2225
2226 int count_fls, nsec_fls, frequency_fls, sec_fls;
2227
2228 count_fls = fls64(count);
2229 nsec_fls = fls64(nsec);
2230 frequency_fls = fls64(frequency);
2231 sec_fls = 30;
2232
2233 /*
2234 * We got @count in @nsec, with a target of sample_freq HZ
2235 * the target period becomes:
2236 *
2237 * @count * 10^9
2238 * period = -------------------
2239 * @nsec * sample_freq
2240 *
2241 */
2242
2243 /*
2244 * Reduce accuracy by one bit such that @a and @b converge
2245 * to a similar magnitude.
2246 */
2247#define REDUCE_FLS(a, b) \
2248do { \
2249 if (a##_fls > b##_fls) { \
2250 a >>= 1; \
2251 a##_fls--; \
2252 } else { \
2253 b >>= 1; \
2254 b##_fls--; \
2255 } \
2256} while (0)
2257
2258 /*
2259 * Reduce accuracy until either term fits in a u64, then proceed with
2260 * the other, so that finally we can do a u64/u64 division.
2261 */
2262 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
2263 REDUCE_FLS(nsec, frequency);
2264 REDUCE_FLS(sec, count);
2265 }
2266
2267 if (count_fls + sec_fls > 64) {
2268 divisor = nsec * frequency;
2269
2270 while (count_fls + sec_fls > 64) {
2271 REDUCE_FLS(count, sec);
2272 divisor >>= 1;
2273 }
2274
2275 dividend = count * sec;
2276 } else {
2277 dividend = count * sec;
2278
2279 while (nsec_fls + frequency_fls > 64) {
2280 REDUCE_FLS(nsec, frequency);
2281 dividend >>= 1;
2282 }
2283
2284 divisor = nsec * frequency;
2285 }
2286
2287 if (!divisor)
2288 return dividend;
2289
2290 return div64_u64(dividend, divisor);
2291}
2292
2293static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count)
2294{
2295 struct hw_perf_event *hwc = &event->hw;
2296 s64 period, sample_period;
2297 s64 delta;
2298
2299 period = perf_calculate_period(event, nsec, count);
2300
2301 delta = (s64)(period - hwc->sample_period);
2302 delta = (delta + 7) / 8; /* low pass filter */
2303
2304 sample_period = hwc->sample_period + delta;
2305
2306 if (!sample_period)
2307 sample_period = 1;
2308
2309 hwc->sample_period = sample_period;
2310
2311 if (local64_read(&hwc->period_left) > 8*sample_period) {
2312 event->pmu->stop(event, PERF_EF_UPDATE);
2313 local64_set(&hwc->period_left, 0);
2314 event->pmu->start(event, PERF_EF_RELOAD);
2315 }
2316}
2317
2318static void perf_ctx_adjust_freq(struct perf_event_context *ctx, u64 period)
2319{
2320 struct perf_event *event;
2321 struct hw_perf_event *hwc;
2322 u64 interrupts, now;
2323 s64 delta;
2324
2325 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
2326 if (event->state != PERF_EVENT_STATE_ACTIVE)
2327 continue;
2328
2329 if (!event_filter_match(event))
2330 continue;
2331
2332 hwc = &event->hw;
2333
2334 interrupts = hwc->interrupts;
2335 hwc->interrupts = 0;
2336
2337 /*
2338 * unthrottle events on the tick
2339 */
2340 if (interrupts == MAX_INTERRUPTS) {
2341 perf_log_throttle(event, 1);
2342 event->pmu->start(event, 0);
2343 }
2344
2345 if (!event->attr.freq || !event->attr.sample_freq)
2346 continue;
2347
2348 event->pmu->read(event);
2349 now = local64_read(&event->count);
2350 delta = now - hwc->freq_count_stamp;
2351 hwc->freq_count_stamp = now;
2352
2353 if (delta > 0)
2354 perf_adjust_period(event, period, delta);
2355 }
2356}
2357
2358/*
2359 * Round-robin a context's events:
2360 */
2361static void rotate_ctx(struct perf_event_context *ctx)
2362{
2363 /*
2364 * Rotate the first entry last of non-pinned groups. Rotation might be
2365 * disabled by the inheritance code.
2366 */
2367 if (!ctx->rotate_disable)
2368 list_rotate_left(&ctx->flexible_groups);
2369}
2370
2371/*
2372 * perf_pmu_rotate_start() and perf_rotate_context() are fully serialized
2373 * because they're strictly cpu affine and rotate_start is called with IRQs
2374 * disabled, while rotate_context is called from IRQ context.
2375 */
2376static void perf_rotate_context(struct perf_cpu_context *cpuctx)
2377{
2378 u64 interval = (u64)cpuctx->jiffies_interval * TICK_NSEC;
2379 struct perf_event_context *ctx = NULL;
2380 int rotate = 0, remove = 1;
2381
2382 if (cpuctx->ctx.nr_events) {
2383 remove = 0;
2384 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
2385 rotate = 1;
2386 }
2387
2388 ctx = cpuctx->task_ctx;
2389 if (ctx && ctx->nr_events) {
2390 remove = 0;
2391 if (ctx->nr_events != ctx->nr_active)
2392 rotate = 1;
2393 }
2394
2395 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
2396 perf_pmu_disable(cpuctx->ctx.pmu);
2397 perf_ctx_adjust_freq(&cpuctx->ctx, interval);
2398 if (ctx)
2399 perf_ctx_adjust_freq(ctx, interval);
2400
2401 if (!rotate)
2402 goto done;
2403
2404 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2405 if (ctx)
2406 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
2407
2408 rotate_ctx(&cpuctx->ctx);
2409 if (ctx)
2410 rotate_ctx(ctx);
2411
2412 perf_event_sched_in(cpuctx, ctx, current);
2413
2414done:
2415 if (remove)
2416 list_del_init(&cpuctx->rotation_list);
2417
2418 perf_pmu_enable(cpuctx->ctx.pmu);
2419 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
2420}
2421
2422void perf_event_task_tick(void)
2423{
2424 struct list_head *head = &__get_cpu_var(rotation_list);
2425 struct perf_cpu_context *cpuctx, *tmp;
2426
2427 WARN_ON(!irqs_disabled());
2428
2429 list_for_each_entry_safe(cpuctx, tmp, head, rotation_list) {
2430 if (cpuctx->jiffies_interval == 1 ||
2431 !(jiffies % cpuctx->jiffies_interval))
2432 perf_rotate_context(cpuctx);
2433 }
2434}
2435
2436static int event_enable_on_exec(struct perf_event *event,
2437 struct perf_event_context *ctx)
2438{
2439 if (!event->attr.enable_on_exec)
2440 return 0;
2441
2442 event->attr.enable_on_exec = 0;
2443 if (event->state >= PERF_EVENT_STATE_INACTIVE)
2444 return 0;
2445
2446 __perf_event_mark_enabled(event, ctx);
2447
2448 return 1;
2449}
2450
2451/*
2452 * Enable all of a task's events that have been marked enable-on-exec.
2453 * This expects task == current.
2454 */
2455static void perf_event_enable_on_exec(struct perf_event_context *ctx)
2456{
2457 struct perf_event *event;
2458 unsigned long flags;
2459 int enabled = 0;
2460 int ret;
2461
2462 local_irq_save(flags);
2463 if (!ctx || !ctx->nr_events)
2464 goto out;
2465
2466 /*
2467 * We must ctxsw out cgroup events to avoid conflict
2468 * when invoking perf_task_event_sched_in() later on
2469 * in this function. Otherwise we end up trying to
2470 * ctxswin cgroup events which are already scheduled
2471 * in.
2472 */
2473 perf_cgroup_sched_out(current, NULL);
2474
2475 raw_spin_lock(&ctx->lock);
2476 task_ctx_sched_out(ctx);
2477
2478 list_for_each_entry(event, &ctx->pinned_groups, group_entry) {
2479 ret = event_enable_on_exec(event, ctx);
2480 if (ret)
2481 enabled = 1;
2482 }
2483
2484 list_for_each_entry(event, &ctx->flexible_groups, group_entry) {
2485 ret = event_enable_on_exec(event, ctx);
2486 if (ret)
2487 enabled = 1;
2488 }
2489
2490 /*
2491 * Unclone this context if we enabled any event.
2492 */
2493 if (enabled)
2494 unclone_ctx(ctx);
2495
2496 raw_spin_unlock(&ctx->lock);
2497
2498 /*
2499 * Also calls ctxswin for cgroup events, if any:
2500 */
2501 perf_event_context_sched_in(ctx, ctx->task);
2502out:
2503 local_irq_restore(flags);
2504}
2505
2506/*
2507 * Cross CPU call to read the hardware event
2508 */
2509static void __perf_event_read(void *info)
2510{
2511 struct perf_event *event = info;
2512 struct perf_event_context *ctx = event->ctx;
2513 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2514
2515 /*
2516 * If this is a task context, we need to check whether it is
2517 * the current task context of this cpu. If not it has been
2518 * scheduled out before the smp call arrived. In that case
2519 * event->count would have been updated to a recent sample
2520 * when the event was scheduled out.
2521 */
2522 if (ctx->task && cpuctx->task_ctx != ctx)
2523 return;
2524
2525 raw_spin_lock(&ctx->lock);
2526 if (ctx->is_active) {
2527 update_context_time(ctx);
2528 update_cgrp_time_from_event(event);
2529 }
2530 update_event_times(event);
2531 if (event->state == PERF_EVENT_STATE_ACTIVE)
2532 event->pmu->read(event);
2533 raw_spin_unlock(&ctx->lock);
2534}
2535
2536static inline u64 perf_event_count(struct perf_event *event)
2537{
2538 return local64_read(&event->count) + atomic64_read(&event->child_count);
2539}
2540
2541static u64 perf_event_read(struct perf_event *event)
2542{
2543 /*
2544 * If event is enabled and currently active on a CPU, update the
2545 * value in the event structure:
2546 */
2547 if (event->state == PERF_EVENT_STATE_ACTIVE) {
2548 smp_call_function_single(event->oncpu,
2549 __perf_event_read, event, 1);
2550 } else if (event->state == PERF_EVENT_STATE_INACTIVE) {
2551 struct perf_event_context *ctx = event->ctx;
2552 unsigned long flags;
2553
2554 raw_spin_lock_irqsave(&ctx->lock, flags);
2555 /*
2556 * may read while context is not active
2557 * (e.g., thread is blocked), in that case
2558 * we cannot update context time
2559 */
2560 if (ctx->is_active) {
2561 update_context_time(ctx);
2562 update_cgrp_time_from_event(event);
2563 }
2564 update_event_times(event);
2565 raw_spin_unlock_irqrestore(&ctx->lock, flags);
2566 }
2567
2568 return perf_event_count(event);
2569}
2570
2571/*
2572 * Callchain support
2573 */
2574
2575struct callchain_cpus_entries {
2576 struct rcu_head rcu_head;
2577 struct perf_callchain_entry *cpu_entries[0];
2578};
2579
2580static DEFINE_PER_CPU(int, callchain_recursion[PERF_NR_CONTEXTS]);
2581static atomic_t nr_callchain_events;
2582static DEFINE_MUTEX(callchain_mutex);
2583struct callchain_cpus_entries *callchain_cpus_entries;
2584
2585
2586__weak void perf_callchain_kernel(struct perf_callchain_entry *entry,
2587 struct pt_regs *regs)
2588{
2589}
2590
2591__weak void perf_callchain_user(struct perf_callchain_entry *entry,
2592 struct pt_regs *regs)
2593{
2594}
2595
2596static void release_callchain_buffers_rcu(struct rcu_head *head)
2597{
2598 struct callchain_cpus_entries *entries;
2599 int cpu;
2600
2601 entries = container_of(head, struct callchain_cpus_entries, rcu_head);
2602
2603 for_each_possible_cpu(cpu)
2604 kfree(entries->cpu_entries[cpu]);
2605
2606 kfree(entries);
2607}
2608
2609static void release_callchain_buffers(void)
2610{
2611 struct callchain_cpus_entries *entries;
2612
2613 entries = callchain_cpus_entries;
2614 rcu_assign_pointer(callchain_cpus_entries, NULL);
2615 call_rcu(&entries->rcu_head, release_callchain_buffers_rcu);
2616}
2617
2618static int alloc_callchain_buffers(void)
2619{
2620 int cpu;
2621 int size;
2622 struct callchain_cpus_entries *entries;
2623
2624 /*
2625 * We can't use the percpu allocation API for data that can be
2626 * accessed from NMI. Use a temporary manual per cpu allocation
2627 * until that gets sorted out.
2628 */
2629 size = offsetof(struct callchain_cpus_entries, cpu_entries[nr_cpu_ids]);
2630
2631 entries = kzalloc(size, GFP_KERNEL);
2632 if (!entries)
2633 return -ENOMEM;
2634
2635 size = sizeof(struct perf_callchain_entry) * PERF_NR_CONTEXTS;
2636
2637 for_each_possible_cpu(cpu) {
2638 entries->cpu_entries[cpu] = kmalloc_node(size, GFP_KERNEL,
2639 cpu_to_node(cpu));
2640 if (!entries->cpu_entries[cpu])
2641 goto fail;
2642 }
2643
2644 rcu_assign_pointer(callchain_cpus_entries, entries);
2645
2646 return 0;
2647
2648fail:
2649 for_each_possible_cpu(cpu)
2650 kfree(entries->cpu_entries[cpu]);
2651 kfree(entries);
2652
2653 return -ENOMEM;
2654}
2655
2656static int get_callchain_buffers(void)
2657{
2658 int err = 0;
2659 int count;
2660
2661 mutex_lock(&callchain_mutex);
2662
2663 count = atomic_inc_return(&nr_callchain_events);
2664 if (WARN_ON_ONCE(count < 1)) {
2665 err = -EINVAL;
2666 goto exit;
2667 }
2668
2669 if (count > 1) {
2670 /* If the allocation failed, give up */
2671 if (!callchain_cpus_entries)
2672 err = -ENOMEM;
2673 goto exit;
2674 }
2675
2676 err = alloc_callchain_buffers();
2677 if (err)
2678 release_callchain_buffers();
2679exit:
2680 mutex_unlock(&callchain_mutex);
2681
2682 return err;
2683}
2684
2685static void put_callchain_buffers(void)
2686{
2687 if (atomic_dec_and_mutex_lock(&nr_callchain_events, &callchain_mutex)) {
2688 release_callchain_buffers();
2689 mutex_unlock(&callchain_mutex);
2690 }
2691}
2692
2693static int get_recursion_context(int *recursion)
2694{
2695 int rctx;
2696
2697 if (in_nmi())
2698 rctx = 3;
2699 else if (in_irq())
2700 rctx = 2;
2701 else if (in_softirq())
2702 rctx = 1;
2703 else
2704 rctx = 0;
2705
2706 if (recursion[rctx])
2707 return -1;
2708
2709 recursion[rctx]++;
2710 barrier();
2711
2712 return rctx;
2713}
2714
2715static inline void put_recursion_context(int *recursion, int rctx)
2716{
2717 barrier();
2718 recursion[rctx]--;
2719}
2720
2721static struct perf_callchain_entry *get_callchain_entry(int *rctx)
2722{
2723 int cpu;
2724 struct callchain_cpus_entries *entries;
2725
2726 *rctx = get_recursion_context(__get_cpu_var(callchain_recursion));
2727 if (*rctx == -1)
2728 return NULL;
2729
2730 entries = rcu_dereference(callchain_cpus_entries);
2731 if (!entries)
2732 return NULL;
2733
2734 cpu = smp_processor_id();
2735
2736 return &entries->cpu_entries[cpu][*rctx];
2737}
2738
2739static void
2740put_callchain_entry(int rctx)
2741{
2742 put_recursion_context(__get_cpu_var(callchain_recursion), rctx);
2743}
2744
2745static struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
2746{
2747 int rctx;
2748 struct perf_callchain_entry *entry;
2749
2750
2751 entry = get_callchain_entry(&rctx);
2752 if (rctx == -1)
2753 return NULL;
2754
2755 if (!entry)
2756 goto exit_put;
2757
2758 entry->nr = 0;
2759
2760 if (!user_mode(regs)) {
2761 perf_callchain_store(entry, PERF_CONTEXT_KERNEL);
2762 perf_callchain_kernel(entry, regs);
2763 if (current->mm)
2764 regs = task_pt_regs(current);
2765 else
2766 regs = NULL;
2767 }
2768
2769 if (regs) {
2770 perf_callchain_store(entry, PERF_CONTEXT_USER);
2771 perf_callchain_user(entry, regs);
2772 }
2773
2774exit_put:
2775 put_callchain_entry(rctx);
2776
2777 return entry;
2778}
2779
2780/*
2781 * Initialize the perf_event context in a task_struct:
2782 */
2783static void __perf_event_init_context(struct perf_event_context *ctx)
2784{
2785 raw_spin_lock_init(&ctx->lock);
2786 mutex_init(&ctx->mutex);
2787 INIT_LIST_HEAD(&ctx->pinned_groups);
2788 INIT_LIST_HEAD(&ctx->flexible_groups);
2789 INIT_LIST_HEAD(&ctx->event_list);
2790 atomic_set(&ctx->refcount, 1);
2791}
2792
2793static struct perf_event_context *
2794alloc_perf_context(struct pmu *pmu, struct task_struct *task)
2795{
2796 struct perf_event_context *ctx;
2797
2798 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
2799 if (!ctx)
2800 return NULL;
2801
2802 __perf_event_init_context(ctx);
2803 if (task) {
2804 ctx->task = task;
2805 get_task_struct(task);
2806 }
2807 ctx->pmu = pmu;
2808
2809 return ctx;
2810}
2811
2812static struct task_struct *
2813find_lively_task_by_vpid(pid_t vpid)
2814{
2815 struct task_struct *task;
2816 int err;
2817
2818 rcu_read_lock();
2819 if (!vpid)
2820 task = current;
2821 else
2822 task = find_task_by_vpid(vpid);
2823 if (task)
2824 get_task_struct(task);
2825 rcu_read_unlock();
2826
2827 if (!task)
2828 return ERR_PTR(-ESRCH);
2829
2830 /* Reuse ptrace permission checks for now. */
2831 err = -EACCES;
2832 if (!ptrace_may_access(task, PTRACE_MODE_READ))
2833 goto errout;
2834
2835 return task;
2836errout:
2837 put_task_struct(task);
2838 return ERR_PTR(err);
2839
2840}
2841
2842/*
2843 * Returns a matching context with refcount and pincount.
2844 */
2845static struct perf_event_context *
2846find_get_context(struct pmu *pmu, struct task_struct *task, int cpu)
2847{
2848 struct perf_event_context *ctx;
2849 struct perf_cpu_context *cpuctx;
2850 unsigned long flags;
2851 int ctxn, err;
2852
2853 if (!task) {
2854 /* Must be root to operate on a CPU event: */
2855 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
2856 return ERR_PTR(-EACCES);
2857
2858 /*
2859 * We could be clever and allow to attach a event to an
2860 * offline CPU and activate it when the CPU comes up, but
2861 * that's for later.
2862 */
2863 if (!cpu_online(cpu))
2864 return ERR_PTR(-ENODEV);
2865
2866 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
2867 ctx = &cpuctx->ctx;
2868 get_ctx(ctx);
2869 ++ctx->pin_count;
2870
2871 return ctx;
2872 }
2873
2874 err = -EINVAL;
2875 ctxn = pmu->task_ctx_nr;
2876 if (ctxn < 0)
2877 goto errout;
2878
2879retry:
2880 ctx = perf_lock_task_context(task, ctxn, &flags);
2881 if (ctx) {
2882 unclone_ctx(ctx);
2883 ++ctx->pin_count;
2884 raw_spin_unlock_irqrestore(&ctx->lock, flags);
2885 } else {
2886 ctx = alloc_perf_context(pmu, task);
2887 err = -ENOMEM;
2888 if (!ctx)
2889 goto errout;
2890
2891 err = 0;
2892 mutex_lock(&task->perf_event_mutex);
2893 /*
2894 * If it has already passed perf_event_exit_task().
2895 * we must see PF_EXITING, it takes this mutex too.
2896 */
2897 if (task->flags & PF_EXITING)
2898 err = -ESRCH;
2899 else if (task->perf_event_ctxp[ctxn])
2900 err = -EAGAIN;
2901 else {
2902 get_ctx(ctx);
2903 ++ctx->pin_count;
2904 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
2905 }
2906 mutex_unlock(&task->perf_event_mutex);
2907
2908 if (unlikely(err)) {
2909 put_ctx(ctx);
2910
2911 if (err == -EAGAIN)
2912 goto retry;
2913 goto errout;
2914 }
2915 }
2916
2917 return ctx;
2918
2919errout:
2920 return ERR_PTR(err);
2921}
2922
2923static void perf_event_free_filter(struct perf_event *event);
2924
2925static void free_event_rcu(struct rcu_head *head)
2926{
2927 struct perf_event *event;
2928
2929 event = container_of(head, struct perf_event, rcu_head);
2930 if (event->ns)
2931 put_pid_ns(event->ns);
2932 perf_event_free_filter(event);
2933 kfree(event);
2934}
2935
2936static void ring_buffer_put(struct ring_buffer *rb);
2937
2938static void free_event(struct perf_event *event)
2939{
2940 irq_work_sync(&event->pending);
2941
2942 if (!event->parent) {
2943 if (event->attach_state & PERF_ATTACH_TASK)
2944 jump_label_dec(&perf_sched_events);
2945 if (event->attr.mmap || event->attr.mmap_data)
2946 atomic_dec(&nr_mmap_events);
2947 if (event->attr.comm)
2948 atomic_dec(&nr_comm_events);
2949 if (event->attr.task)
2950 atomic_dec(&nr_task_events);
2951 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
2952 put_callchain_buffers();
2953 if (is_cgroup_event(event)) {
2954 atomic_dec(&per_cpu(perf_cgroup_events, event->cpu));
2955 jump_label_dec(&perf_sched_events);
2956 }
2957 }
2958
2959 if (event->rb) {
2960 ring_buffer_put(event->rb);
2961 event->rb = NULL;
2962 }
2963
2964 if (is_cgroup_event(event))
2965 perf_detach_cgroup(event);
2966
2967 if (event->destroy)
2968 event->destroy(event);
2969
2970 if (event->ctx)
2971 put_ctx(event->ctx);
2972
2973 call_rcu(&event->rcu_head, free_event_rcu);
2974}
2975
2976int perf_event_release_kernel(struct perf_event *event)
2977{
2978 struct perf_event_context *ctx = event->ctx;
2979
2980 WARN_ON_ONCE(ctx->parent_ctx);
2981 /*
2982 * There are two ways this annotation is useful:
2983 *
2984 * 1) there is a lock recursion from perf_event_exit_task
2985 * see the comment there.
2986 *
2987 * 2) there is a lock-inversion with mmap_sem through
2988 * perf_event_read_group(), which takes faults while
2989 * holding ctx->mutex, however this is called after
2990 * the last filedesc died, so there is no possibility
2991 * to trigger the AB-BA case.
2992 */
2993 mutex_lock_nested(&ctx->mutex, SINGLE_DEPTH_NESTING);
2994 raw_spin_lock_irq(&ctx->lock);
2995 perf_group_detach(event);
2996 raw_spin_unlock_irq(&ctx->lock);
2997 perf_remove_from_context(event);
2998 mutex_unlock(&ctx->mutex);
2999
3000 free_event(event);
3001
3002 return 0;
3003}
3004EXPORT_SYMBOL_GPL(perf_event_release_kernel);
3005
3006/*
3007 * Called when the last reference to the file is gone.
3008 */
3009static int perf_release(struct inode *inode, struct file *file)
3010{
3011 struct perf_event *event = file->private_data;
3012 struct task_struct *owner;
3013
3014 file->private_data = NULL;
3015
3016 rcu_read_lock();
3017 owner = ACCESS_ONCE(event->owner);
3018 /*
3019 * Matches the smp_wmb() in perf_event_exit_task(). If we observe
3020 * !owner it means the list deletion is complete and we can indeed
3021 * free this event, otherwise we need to serialize on
3022 * owner->perf_event_mutex.
3023 */
3024 smp_read_barrier_depends();
3025 if (owner) {
3026 /*
3027 * Since delayed_put_task_struct() also drops the last
3028 * task reference we can safely take a new reference
3029 * while holding the rcu_read_lock().
3030 */
3031 get_task_struct(owner);
3032 }
3033 rcu_read_unlock();
3034
3035 if (owner) {
3036 mutex_lock(&owner->perf_event_mutex);
3037 /*
3038 * We have to re-check the event->owner field, if it is cleared
3039 * we raced with perf_event_exit_task(), acquiring the mutex
3040 * ensured they're done, and we can proceed with freeing the
3041 * event.
3042 */
3043 if (event->owner)
3044 list_del_init(&event->owner_entry);
3045 mutex_unlock(&owner->perf_event_mutex);
3046 put_task_struct(owner);
3047 }
3048
3049 return perf_event_release_kernel(event);
3050}
3051
3052u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
3053{
3054 struct perf_event *child;
3055 u64 total = 0;
3056
3057 *enabled = 0;
3058 *running = 0;
3059
3060 mutex_lock(&event->child_mutex);
3061 total += perf_event_read(event);
3062 *enabled += event->total_time_enabled +
3063 atomic64_read(&event->child_total_time_enabled);
3064 *running += event->total_time_running +
3065 atomic64_read(&event->child_total_time_running);
3066
3067 list_for_each_entry(child, &event->child_list, child_list) {
3068 total += perf_event_read(child);
3069 *enabled += child->total_time_enabled;
3070 *running += child->total_time_running;
3071 }
3072 mutex_unlock(&event->child_mutex);
3073
3074 return total;
3075}
3076EXPORT_SYMBOL_GPL(perf_event_read_value);
3077
3078static int perf_event_read_group(struct perf_event *event,
3079 u64 read_format, char __user *buf)
3080{
3081 struct perf_event *leader = event->group_leader, *sub;
3082 int n = 0, size = 0, ret = -EFAULT;
3083 struct perf_event_context *ctx = leader->ctx;
3084 u64 values[5];
3085 u64 count, enabled, running;
3086
3087 mutex_lock(&ctx->mutex);
3088 count = perf_event_read_value(leader, &enabled, &running);
3089
3090 values[n++] = 1 + leader->nr_siblings;
3091 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3092 values[n++] = enabled;
3093 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3094 values[n++] = running;
3095 values[n++] = count;
3096 if (read_format & PERF_FORMAT_ID)
3097 values[n++] = primary_event_id(leader);
3098
3099 size = n * sizeof(u64);
3100
3101 if (copy_to_user(buf, values, size))
3102 goto unlock;
3103
3104 ret = size;
3105
3106 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3107 n = 0;
3108
3109 values[n++] = perf_event_read_value(sub, &enabled, &running);
3110 if (read_format & PERF_FORMAT_ID)
3111 values[n++] = primary_event_id(sub);
3112
3113 size = n * sizeof(u64);
3114
3115 if (copy_to_user(buf + ret, values, size)) {
3116 ret = -EFAULT;
3117 goto unlock;
3118 }
3119
3120 ret += size;
3121 }
3122unlock:
3123 mutex_unlock(&ctx->mutex);
3124
3125 return ret;
3126}
3127
3128static int perf_event_read_one(struct perf_event *event,
3129 u64 read_format, char __user *buf)
3130{
3131 u64 enabled, running;
3132 u64 values[4];
3133 int n = 0;
3134
3135 values[n++] = perf_event_read_value(event, &enabled, &running);
3136 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3137 values[n++] = enabled;
3138 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3139 values[n++] = running;
3140 if (read_format & PERF_FORMAT_ID)
3141 values[n++] = primary_event_id(event);
3142
3143 if (copy_to_user(buf, values, n * sizeof(u64)))
3144 return -EFAULT;
3145
3146 return n * sizeof(u64);
3147}
3148
3149/*
3150 * Read the performance event - simple non blocking version for now
3151 */
3152static ssize_t
3153perf_read_hw(struct perf_event *event, char __user *buf, size_t count)
3154{
3155 u64 read_format = event->attr.read_format;
3156 int ret;
3157
3158 /*
3159 * Return end-of-file for a read on a event that is in
3160 * error state (i.e. because it was pinned but it couldn't be
3161 * scheduled on to the CPU at some point).
3162 */
3163 if (event->state == PERF_EVENT_STATE_ERROR)
3164 return 0;
3165
3166 if (count < event->read_size)
3167 return -ENOSPC;
3168
3169 WARN_ON_ONCE(event->ctx->parent_ctx);
3170 if (read_format & PERF_FORMAT_GROUP)
3171 ret = perf_event_read_group(event, read_format, buf);
3172 else
3173 ret = perf_event_read_one(event, read_format, buf);
3174
3175 return ret;
3176}
3177
3178static ssize_t
3179perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
3180{
3181 struct perf_event *event = file->private_data;
3182
3183 return perf_read_hw(event, buf, count);
3184}
3185
3186static unsigned int perf_poll(struct file *file, poll_table *wait)
3187{
3188 struct perf_event *event = file->private_data;
3189 struct ring_buffer *rb;
3190 unsigned int events = POLL_HUP;
3191
3192 rcu_read_lock();
3193 rb = rcu_dereference(event->rb);
3194 if (rb)
3195 events = atomic_xchg(&rb->poll, 0);
3196 rcu_read_unlock();
3197
3198 poll_wait(file, &event->waitq, wait);
3199
3200 return events;
3201}
3202
3203static void perf_event_reset(struct perf_event *event)
3204{
3205 (void)perf_event_read(event);
3206 local64_set(&event->count, 0);
3207 perf_event_update_userpage(event);
3208}
3209
3210/*
3211 * Holding the top-level event's child_mutex means that any
3212 * descendant process that has inherited this event will block
3213 * in sync_child_event if it goes to exit, thus satisfying the
3214 * task existence requirements of perf_event_enable/disable.
3215 */
3216static void perf_event_for_each_child(struct perf_event *event,
3217 void (*func)(struct perf_event *))
3218{
3219 struct perf_event *child;
3220
3221 WARN_ON_ONCE(event->ctx->parent_ctx);
3222 mutex_lock(&event->child_mutex);
3223 func(event);
3224 list_for_each_entry(child, &event->child_list, child_list)
3225 func(child);
3226 mutex_unlock(&event->child_mutex);
3227}
3228
3229static void perf_event_for_each(struct perf_event *event,
3230 void (*func)(struct perf_event *))
3231{
3232 struct perf_event_context *ctx = event->ctx;
3233 struct perf_event *sibling;
3234
3235 WARN_ON_ONCE(ctx->parent_ctx);
3236 mutex_lock(&ctx->mutex);
3237 event = event->group_leader;
3238
3239 perf_event_for_each_child(event, func);
3240 func(event);
3241 list_for_each_entry(sibling, &event->sibling_list, group_entry)
3242 perf_event_for_each_child(event, func);
3243 mutex_unlock(&ctx->mutex);
3244}
3245
3246static int perf_event_period(struct perf_event *event, u64 __user *arg)
3247{
3248 struct perf_event_context *ctx = event->ctx;
3249 int ret = 0;
3250 u64 value;
3251
3252 if (!is_sampling_event(event))
3253 return -EINVAL;
3254
3255 if (copy_from_user(&value, arg, sizeof(value)))
3256 return -EFAULT;
3257
3258 if (!value)
3259 return -EINVAL;
3260
3261 raw_spin_lock_irq(&ctx->lock);
3262 if (event->attr.freq) {
3263 if (value > sysctl_perf_event_sample_rate) {
3264 ret = -EINVAL;
3265 goto unlock;
3266 }
3267
3268 event->attr.sample_freq = value;
3269 } else {
3270 event->attr.sample_period = value;
3271 event->hw.sample_period = value;
3272 }
3273unlock:
3274 raw_spin_unlock_irq(&ctx->lock);
3275
3276 return ret;
3277}
3278
3279static const struct file_operations perf_fops;
3280
3281static struct perf_event *perf_fget_light(int fd, int *fput_needed)
3282{
3283 struct file *file;
3284
3285 file = fget_light(fd, fput_needed);
3286 if (!file)
3287 return ERR_PTR(-EBADF);
3288
3289 if (file->f_op != &perf_fops) {
3290 fput_light(file, *fput_needed);
3291 *fput_needed = 0;
3292 return ERR_PTR(-EBADF);
3293 }
3294
3295 return file->private_data;
3296}
3297
3298static int perf_event_set_output(struct perf_event *event,
3299 struct perf_event *output_event);
3300static int perf_event_set_filter(struct perf_event *event, void __user *arg);
3301
3302static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
3303{
3304 struct perf_event *event = file->private_data;
3305 void (*func)(struct perf_event *);
3306 u32 flags = arg;
3307
3308 switch (cmd) {
3309 case PERF_EVENT_IOC_ENABLE:
3310 func = perf_event_enable;
3311 break;
3312 case PERF_EVENT_IOC_DISABLE:
3313 func = perf_event_disable;
3314 break;
3315 case PERF_EVENT_IOC_RESET:
3316 func = perf_event_reset;
3317 break;
3318
3319 case PERF_EVENT_IOC_REFRESH:
3320 return perf_event_refresh(event, arg);
3321
3322 case PERF_EVENT_IOC_PERIOD:
3323 return perf_event_period(event, (u64 __user *)arg);
3324
3325 case PERF_EVENT_IOC_SET_OUTPUT:
3326 {
3327 struct perf_event *output_event = NULL;
3328 int fput_needed = 0;
3329 int ret;
3330
3331 if (arg != -1) {
3332 output_event = perf_fget_light(arg, &fput_needed);
3333 if (IS_ERR(output_event))
3334 return PTR_ERR(output_event);
3335 }
3336
3337 ret = perf_event_set_output(event, output_event);
3338 if (output_event)
3339 fput_light(output_event->filp, fput_needed);
3340
3341 return ret;
3342 }
3343
3344 case PERF_EVENT_IOC_SET_FILTER:
3345 return perf_event_set_filter(event, (void __user *)arg);
3346
3347 default:
3348 return -ENOTTY;
3349 }
3350
3351 if (flags & PERF_IOC_FLAG_GROUP)
3352 perf_event_for_each(event, func);
3353 else
3354 perf_event_for_each_child(event, func);
3355
3356 return 0;
3357}
3358
3359int perf_event_task_enable(void)
3360{
3361 struct perf_event *event;
3362
3363 mutex_lock(¤t->perf_event_mutex);
3364 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
3365 perf_event_for_each_child(event, perf_event_enable);
3366 mutex_unlock(¤t->perf_event_mutex);
3367
3368 return 0;
3369}
3370
3371int perf_event_task_disable(void)
3372{
3373 struct perf_event *event;
3374
3375 mutex_lock(¤t->perf_event_mutex);
3376 list_for_each_entry(event, ¤t->perf_event_list, owner_entry)
3377 perf_event_for_each_child(event, perf_event_disable);
3378 mutex_unlock(¤t->perf_event_mutex);
3379
3380 return 0;
3381}
3382
3383#ifndef PERF_EVENT_INDEX_OFFSET
3384# define PERF_EVENT_INDEX_OFFSET 0
3385#endif
3386
3387static int perf_event_index(struct perf_event *event)
3388{
3389 if (event->hw.state & PERF_HES_STOPPED)
3390 return 0;
3391
3392 if (event->state != PERF_EVENT_STATE_ACTIVE)
3393 return 0;
3394
3395 return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET;
3396}
3397
3398static void calc_timer_values(struct perf_event *event,
3399 u64 *enabled,
3400 u64 *running)
3401{
3402 u64 now, ctx_time;
3403
3404 now = perf_clock();
3405 ctx_time = event->shadow_ctx_time + now;
3406 *enabled = ctx_time - event->tstamp_enabled;
3407 *running = ctx_time - event->tstamp_running;
3408}
3409
3410/*
3411 * Callers need to ensure there can be no nesting of this function, otherwise
3412 * the seqlock logic goes bad. We can not serialize this because the arch
3413 * code calls this from NMI context.
3414 */
3415void perf_event_update_userpage(struct perf_event *event)
3416{
3417 struct perf_event_mmap_page *userpg;
3418 struct ring_buffer *rb;
3419 u64 enabled, running;
3420
3421 rcu_read_lock();
3422 /*
3423 * compute total_time_enabled, total_time_running
3424 * based on snapshot values taken when the event
3425 * was last scheduled in.
3426 *
3427 * we cannot simply called update_context_time()
3428 * because of locking issue as we can be called in
3429 * NMI context
3430 */
3431 calc_timer_values(event, &enabled, &running);
3432 rb = rcu_dereference(event->rb);
3433 if (!rb)
3434 goto unlock;
3435
3436 userpg = rb->user_page;
3437
3438 /*
3439 * Disable preemption so as to not let the corresponding user-space
3440 * spin too long if we get preempted.
3441 */
3442 preempt_disable();
3443 ++userpg->lock;
3444 barrier();
3445 userpg->index = perf_event_index(event);
3446 userpg->offset = perf_event_count(event);
3447 if (event->state == PERF_EVENT_STATE_ACTIVE)
3448 userpg->offset -= local64_read(&event->hw.prev_count);
3449
3450 userpg->time_enabled = enabled +
3451 atomic64_read(&event->child_total_time_enabled);
3452
3453 userpg->time_running = running +
3454 atomic64_read(&event->child_total_time_running);
3455
3456 barrier();
3457 ++userpg->lock;
3458 preempt_enable();
3459unlock:
3460 rcu_read_unlock();
3461}
3462
3463static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
3464{
3465 struct perf_event *event = vma->vm_file->private_data;
3466 struct ring_buffer *rb;
3467 int ret = VM_FAULT_SIGBUS;
3468
3469 if (vmf->flags & FAULT_FLAG_MKWRITE) {
3470 if (vmf->pgoff == 0)
3471 ret = 0;
3472 return ret;
3473 }
3474
3475 rcu_read_lock();
3476 rb = rcu_dereference(event->rb);
3477 if (!rb)
3478 goto unlock;
3479
3480 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
3481 goto unlock;
3482
3483 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
3484 if (!vmf->page)
3485 goto unlock;
3486
3487 get_page(vmf->page);
3488 vmf->page->mapping = vma->vm_file->f_mapping;
3489 vmf->page->index = vmf->pgoff;
3490
3491 ret = 0;
3492unlock:
3493 rcu_read_unlock();
3494
3495 return ret;
3496}
3497
3498static void rb_free_rcu(struct rcu_head *rcu_head)
3499{
3500 struct ring_buffer *rb;
3501
3502 rb = container_of(rcu_head, struct ring_buffer, rcu_head);
3503 rb_free(rb);
3504}
3505
3506static struct ring_buffer *ring_buffer_get(struct perf_event *event)
3507{
3508 struct ring_buffer *rb;
3509
3510 rcu_read_lock();
3511 rb = rcu_dereference(event->rb);
3512 if (rb) {
3513 if (!atomic_inc_not_zero(&rb->refcount))
3514 rb = NULL;
3515 }
3516 rcu_read_unlock();
3517
3518 return rb;
3519}
3520
3521static void ring_buffer_put(struct ring_buffer *rb)
3522{
3523 if (!atomic_dec_and_test(&rb->refcount))
3524 return;
3525
3526 call_rcu(&rb->rcu_head, rb_free_rcu);
3527}
3528
3529static void perf_mmap_open(struct vm_area_struct *vma)
3530{
3531 struct perf_event *event = vma->vm_file->private_data;
3532
3533 atomic_inc(&event->mmap_count);
3534}
3535
3536static void perf_mmap_close(struct vm_area_struct *vma)
3537{
3538 struct perf_event *event = vma->vm_file->private_data;
3539
3540 if (atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex)) {
3541 unsigned long size = perf_data_size(event->rb);
3542 struct user_struct *user = event->mmap_user;
3543 struct ring_buffer *rb = event->rb;
3544
3545 atomic_long_sub((size >> PAGE_SHIFT) + 1, &user->locked_vm);
3546 vma->vm_mm->locked_vm -= event->mmap_locked;
3547 rcu_assign_pointer(event->rb, NULL);
3548 mutex_unlock(&event->mmap_mutex);
3549
3550 ring_buffer_put(rb);
3551 free_uid(user);
3552 }
3553}
3554
3555static const struct vm_operations_struct perf_mmap_vmops = {
3556 .open = perf_mmap_open,
3557 .close = perf_mmap_close,
3558 .fault = perf_mmap_fault,
3559 .page_mkwrite = perf_mmap_fault,
3560};
3561
3562static int perf_mmap(struct file *file, struct vm_area_struct *vma)
3563{
3564 struct perf_event *event = file->private_data;
3565 unsigned long user_locked, user_lock_limit;
3566 struct user_struct *user = current_user();
3567 unsigned long locked, lock_limit;
3568 struct ring_buffer *rb;
3569 unsigned long vma_size;
3570 unsigned long nr_pages;
3571 long user_extra, extra;
3572 int ret = 0, flags = 0;
3573
3574 /*
3575 * Don't allow mmap() of inherited per-task counters. This would
3576 * create a performance issue due to all children writing to the
3577 * same rb.
3578 */
3579 if (event->cpu == -1 && event->attr.inherit)
3580 return -EINVAL;
3581
3582 if (!(vma->vm_flags & VM_SHARED))
3583 return -EINVAL;
3584
3585 vma_size = vma->vm_end - vma->vm_start;
3586 nr_pages = (vma_size / PAGE_SIZE) - 1;
3587
3588 /*
3589 * If we have rb pages ensure they're a power-of-two number, so we
3590 * can do bitmasks instead of modulo.
3591 */
3592 if (nr_pages != 0 && !is_power_of_2(nr_pages))
3593 return -EINVAL;
3594
3595 if (vma_size != PAGE_SIZE * (1 + nr_pages))
3596 return -EINVAL;
3597
3598 if (vma->vm_pgoff != 0)
3599 return -EINVAL;
3600
3601 WARN_ON_ONCE(event->ctx->parent_ctx);
3602 mutex_lock(&event->mmap_mutex);
3603 if (event->rb) {
3604 if (event->rb->nr_pages == nr_pages)
3605 atomic_inc(&event->rb->refcount);
3606 else
3607 ret = -EINVAL;
3608 goto unlock;
3609 }
3610
3611 user_extra = nr_pages + 1;
3612 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
3613
3614 /*
3615 * Increase the limit linearly with more CPUs:
3616 */
3617 user_lock_limit *= num_online_cpus();
3618
3619 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
3620
3621 extra = 0;
3622 if (user_locked > user_lock_limit)
3623 extra = user_locked - user_lock_limit;
3624
3625 lock_limit = rlimit(RLIMIT_MEMLOCK);
3626 lock_limit >>= PAGE_SHIFT;
3627 locked = vma->vm_mm->locked_vm + extra;
3628
3629 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
3630 !capable(CAP_IPC_LOCK)) {
3631 ret = -EPERM;
3632 goto unlock;
3633 }
3634
3635 WARN_ON(event->rb);
3636
3637 if (vma->vm_flags & VM_WRITE)
3638 flags |= RING_BUFFER_WRITABLE;
3639
3640 rb = rb_alloc(nr_pages,
3641 event->attr.watermark ? event->attr.wakeup_watermark : 0,
3642 event->cpu, flags);
3643
3644 if (!rb) {
3645 ret = -ENOMEM;
3646 goto unlock;
3647 }
3648 rcu_assign_pointer(event->rb, rb);
3649
3650 atomic_long_add(user_extra, &user->locked_vm);
3651 event->mmap_locked = extra;
3652 event->mmap_user = get_current_user();
3653 vma->vm_mm->locked_vm += event->mmap_locked;
3654
3655unlock:
3656 if (!ret)
3657 atomic_inc(&event->mmap_count);
3658 mutex_unlock(&event->mmap_mutex);
3659
3660 vma->vm_flags |= VM_RESERVED;
3661 vma->vm_ops = &perf_mmap_vmops;
3662
3663 return ret;
3664}
3665
3666static int perf_fasync(int fd, struct file *filp, int on)
3667{
3668 struct inode *inode = filp->f_path.dentry->d_inode;
3669 struct perf_event *event = filp->private_data;
3670 int retval;
3671
3672 mutex_lock(&inode->i_mutex);
3673 retval = fasync_helper(fd, filp, on, &event->fasync);
3674 mutex_unlock(&inode->i_mutex);
3675
3676 if (retval < 0)
3677 return retval;
3678
3679 return 0;
3680}
3681
3682static const struct file_operations perf_fops = {
3683 .llseek = no_llseek,
3684 .release = perf_release,
3685 .read = perf_read,
3686 .poll = perf_poll,
3687 .unlocked_ioctl = perf_ioctl,
3688 .compat_ioctl = perf_ioctl,
3689 .mmap = perf_mmap,
3690 .fasync = perf_fasync,
3691};
3692
3693/*
3694 * Perf event wakeup
3695 *
3696 * If there's data, ensure we set the poll() state and publish everything
3697 * to user-space before waking everybody up.
3698 */
3699
3700void perf_event_wakeup(struct perf_event *event)
3701{
3702 wake_up_all(&event->waitq);
3703
3704 if (event->pending_kill) {
3705 kill_fasync(&event->fasync, SIGIO, event->pending_kill);
3706 event->pending_kill = 0;
3707 }
3708}
3709
3710static void perf_pending_event(struct irq_work *entry)
3711{
3712 struct perf_event *event = container_of(entry,
3713 struct perf_event, pending);
3714
3715 if (event->pending_disable) {
3716 event->pending_disable = 0;
3717 __perf_event_disable(event);
3718 }
3719
3720 if (event->pending_wakeup) {
3721 event->pending_wakeup = 0;
3722 perf_event_wakeup(event);
3723 }
3724}
3725
3726/*
3727 * We assume there is only KVM supporting the callbacks.
3728 * Later on, we might change it to a list if there is
3729 * another virtualization implementation supporting the callbacks.
3730 */
3731struct perf_guest_info_callbacks *perf_guest_cbs;
3732
3733int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
3734{
3735 perf_guest_cbs = cbs;
3736 return 0;
3737}
3738EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
3739
3740int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
3741{
3742 perf_guest_cbs = NULL;
3743 return 0;
3744}
3745EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
3746
3747static void __perf_event_header__init_id(struct perf_event_header *header,
3748 struct perf_sample_data *data,
3749 struct perf_event *event)
3750{
3751 u64 sample_type = event->attr.sample_type;
3752
3753 data->type = sample_type;
3754 header->size += event->id_header_size;
3755
3756 if (sample_type & PERF_SAMPLE_TID) {
3757 /* namespace issues */
3758 data->tid_entry.pid = perf_event_pid(event, current);
3759 data->tid_entry.tid = perf_event_tid(event, current);
3760 }
3761
3762 if (sample_type & PERF_SAMPLE_TIME)
3763 data->time = perf_clock();
3764
3765 if (sample_type & PERF_SAMPLE_ID)
3766 data->id = primary_event_id(event);
3767
3768 if (sample_type & PERF_SAMPLE_STREAM_ID)
3769 data->stream_id = event->id;
3770
3771 if (sample_type & PERF_SAMPLE_CPU) {
3772 data->cpu_entry.cpu = raw_smp_processor_id();
3773 data->cpu_entry.reserved = 0;
3774 }
3775}
3776
3777void perf_event_header__init_id(struct perf_event_header *header,
3778 struct perf_sample_data *data,
3779 struct perf_event *event)
3780{
3781 if (event->attr.sample_id_all)
3782 __perf_event_header__init_id(header, data, event);
3783}
3784
3785static void __perf_event__output_id_sample(struct perf_output_handle *handle,
3786 struct perf_sample_data *data)
3787{
3788 u64 sample_type = data->type;
3789
3790 if (sample_type & PERF_SAMPLE_TID)
3791 perf_output_put(handle, data->tid_entry);
3792
3793 if (sample_type & PERF_SAMPLE_TIME)
3794 perf_output_put(handle, data->time);
3795
3796 if (sample_type & PERF_SAMPLE_ID)
3797 perf_output_put(handle, data->id);
3798
3799 if (sample_type & PERF_SAMPLE_STREAM_ID)
3800 perf_output_put(handle, data->stream_id);
3801
3802 if (sample_type & PERF_SAMPLE_CPU)
3803 perf_output_put(handle, data->cpu_entry);
3804}
3805
3806void perf_event__output_id_sample(struct perf_event *event,
3807 struct perf_output_handle *handle,
3808 struct perf_sample_data *sample)
3809{
3810 if (event->attr.sample_id_all)
3811 __perf_event__output_id_sample(handle, sample);
3812}
3813
3814static void perf_output_read_one(struct perf_output_handle *handle,
3815 struct perf_event *event,
3816 u64 enabled, u64 running)
3817{
3818 u64 read_format = event->attr.read_format;
3819 u64 values[4];
3820 int n = 0;
3821
3822 values[n++] = perf_event_count(event);
3823 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
3824 values[n++] = enabled +
3825 atomic64_read(&event->child_total_time_enabled);
3826 }
3827 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
3828 values[n++] = running +
3829 atomic64_read(&event->child_total_time_running);
3830 }
3831 if (read_format & PERF_FORMAT_ID)
3832 values[n++] = primary_event_id(event);
3833
3834 __output_copy(handle, values, n * sizeof(u64));
3835}
3836
3837/*
3838 * XXX PERF_FORMAT_GROUP vs inherited events seems difficult.
3839 */
3840static void perf_output_read_group(struct perf_output_handle *handle,
3841 struct perf_event *event,
3842 u64 enabled, u64 running)
3843{
3844 struct perf_event *leader = event->group_leader, *sub;
3845 u64 read_format = event->attr.read_format;
3846 u64 values[5];
3847 int n = 0;
3848
3849 values[n++] = 1 + leader->nr_siblings;
3850
3851 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
3852 values[n++] = enabled;
3853
3854 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
3855 values[n++] = running;
3856
3857 if (leader != event)
3858 leader->pmu->read(leader);
3859
3860 values[n++] = perf_event_count(leader);
3861 if (read_format & PERF_FORMAT_ID)
3862 values[n++] = primary_event_id(leader);
3863
3864 __output_copy(handle, values, n * sizeof(u64));
3865
3866 list_for_each_entry(sub, &leader->sibling_list, group_entry) {
3867 n = 0;
3868
3869 if (sub != event)
3870 sub->pmu->read(sub);
3871
3872 values[n++] = perf_event_count(sub);
3873 if (read_format & PERF_FORMAT_ID)
3874 values[n++] = primary_event_id(sub);
3875
3876 __output_copy(handle, values, n * sizeof(u64));
3877 }
3878}
3879
3880#define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
3881 PERF_FORMAT_TOTAL_TIME_RUNNING)
3882
3883static void perf_output_read(struct perf_output_handle *handle,
3884 struct perf_event *event)
3885{
3886 u64 enabled = 0, running = 0;
3887 u64 read_format = event->attr.read_format;
3888
3889 /*
3890 * compute total_time_enabled, total_time_running
3891 * based on snapshot values taken when the event
3892 * was last scheduled in.
3893 *
3894 * we cannot simply called update_context_time()
3895 * because of locking issue as we are called in
3896 * NMI context
3897 */
3898 if (read_format & PERF_FORMAT_TOTAL_TIMES)
3899 calc_timer_values(event, &enabled, &running);
3900
3901 if (event->attr.read_format & PERF_FORMAT_GROUP)
3902 perf_output_read_group(handle, event, enabled, running);
3903 else
3904 perf_output_read_one(handle, event, enabled, running);
3905}
3906
3907void perf_output_sample(struct perf_output_handle *handle,
3908 struct perf_event_header *header,
3909 struct perf_sample_data *data,
3910 struct perf_event *event)
3911{
3912 u64 sample_type = data->type;
3913
3914 perf_output_put(handle, *header);
3915
3916 if (sample_type & PERF_SAMPLE_IP)
3917 perf_output_put(handle, data->ip);
3918
3919 if (sample_type & PERF_SAMPLE_TID)
3920 perf_output_put(handle, data->tid_entry);
3921
3922 if (sample_type & PERF_SAMPLE_TIME)
3923 perf_output_put(handle, data->time);
3924
3925 if (sample_type & PERF_SAMPLE_ADDR)
3926 perf_output_put(handle, data->addr);
3927
3928 if (sample_type & PERF_SAMPLE_ID)
3929 perf_output_put(handle, data->id);
3930
3931 if (sample_type & PERF_SAMPLE_STREAM_ID)
3932 perf_output_put(handle, data->stream_id);
3933
3934 if (sample_type & PERF_SAMPLE_CPU)
3935 perf_output_put(handle, data->cpu_entry);
3936
3937 if (sample_type & PERF_SAMPLE_PERIOD)
3938 perf_output_put(handle, data->period);
3939
3940 if (sample_type & PERF_SAMPLE_READ)
3941 perf_output_read(handle, event);
3942
3943 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
3944 if (data->callchain) {
3945 int size = 1;
3946
3947 if (data->callchain)
3948 size += data->callchain->nr;
3949
3950 size *= sizeof(u64);
3951
3952 __output_copy(handle, data->callchain, size);
3953 } else {
3954 u64 nr = 0;
3955 perf_output_put(handle, nr);
3956 }
3957 }
3958
3959 if (sample_type & PERF_SAMPLE_RAW) {
3960 if (data->raw) {
3961 perf_output_put(handle, data->raw->size);
3962 __output_copy(handle, data->raw->data,
3963 data->raw->size);
3964 } else {
3965 struct {
3966 u32 size;
3967 u32 data;
3968 } raw = {
3969 .size = sizeof(u32),
3970 .data = 0,
3971 };
3972 perf_output_put(handle, raw);
3973 }
3974 }
3975
3976 if (!event->attr.watermark) {
3977 int wakeup_events = event->attr.wakeup_events;
3978
3979 if (wakeup_events) {
3980 struct ring_buffer *rb = handle->rb;
3981 int events = local_inc_return(&rb->events);
3982
3983 if (events >= wakeup_events) {
3984 local_sub(wakeup_events, &rb->events);
3985 local_inc(&rb->wakeup);
3986 }
3987 }
3988 }
3989}
3990
3991void perf_prepare_sample(struct perf_event_header *header,
3992 struct perf_sample_data *data,
3993 struct perf_event *event,
3994 struct pt_regs *regs)
3995{
3996 u64 sample_type = event->attr.sample_type;
3997
3998 header->type = PERF_RECORD_SAMPLE;
3999 header->size = sizeof(*header) + event->header_size;
4000
4001 header->misc = 0;
4002 header->misc |= perf_misc_flags(regs);
4003
4004 __perf_event_header__init_id(header, data, event);
4005
4006 if (sample_type & PERF_SAMPLE_IP)
4007 data->ip = perf_instruction_pointer(regs);
4008
4009 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
4010 int size = 1;
4011
4012 data->callchain = perf_callchain(regs);
4013
4014 if (data->callchain)
4015 size += data->callchain->nr;
4016
4017 header->size += size * sizeof(u64);
4018 }
4019
4020 if (sample_type & PERF_SAMPLE_RAW) {
4021 int size = sizeof(u32);
4022
4023 if (data->raw)
4024 size += data->raw->size;
4025 else
4026 size += sizeof(u32);
4027
4028 WARN_ON_ONCE(size & (sizeof(u64)-1));
4029 header->size += size;
4030 }
4031}
4032
4033static void perf_event_output(struct perf_event *event,
4034 struct perf_sample_data *data,
4035 struct pt_regs *regs)
4036{
4037 struct perf_output_handle handle;
4038 struct perf_event_header header;
4039
4040 /* protect the callchain buffers */
4041 rcu_read_lock();
4042
4043 perf_prepare_sample(&header, data, event, regs);
4044
4045 if (perf_output_begin(&handle, event, header.size))
4046 goto exit;
4047
4048 perf_output_sample(&handle, &header, data, event);
4049
4050 perf_output_end(&handle);
4051
4052exit:
4053 rcu_read_unlock();
4054}
4055
4056/*
4057 * read event_id
4058 */
4059
4060struct perf_read_event {
4061 struct perf_event_header header;
4062
4063 u32 pid;
4064 u32 tid;
4065};
4066
4067static void
4068perf_event_read_event(struct perf_event *event,
4069 struct task_struct *task)
4070{
4071 struct perf_output_handle handle;
4072 struct perf_sample_data sample;
4073 struct perf_read_event read_event = {
4074 .header = {
4075 .type = PERF_RECORD_READ,
4076 .misc = 0,
4077 .size = sizeof(read_event) + event->read_size,
4078 },
4079 .pid = perf_event_pid(event, task),
4080 .tid = perf_event_tid(event, task),
4081 };
4082 int ret;
4083
4084 perf_event_header__init_id(&read_event.header, &sample, event);
4085 ret = perf_output_begin(&handle, event, read_event.header.size);
4086 if (ret)
4087 return;
4088
4089 perf_output_put(&handle, read_event);
4090 perf_output_read(&handle, event);
4091 perf_event__output_id_sample(event, &handle, &sample);
4092
4093 perf_output_end(&handle);
4094}
4095
4096/*
4097 * task tracking -- fork/exit
4098 *
4099 * enabled by: attr.comm | attr.mmap | attr.mmap_data | attr.task
4100 */
4101
4102struct perf_task_event {
4103 struct task_struct *task;
4104 struct perf_event_context *task_ctx;
4105
4106 struct {
4107 struct perf_event_header header;
4108
4109 u32 pid;
4110 u32 ppid;
4111 u32 tid;
4112 u32 ptid;
4113 u64 time;
4114 } event_id;
4115};
4116
4117static void perf_event_task_output(struct perf_event *event,
4118 struct perf_task_event *task_event)
4119{
4120 struct perf_output_handle handle;
4121 struct perf_sample_data sample;
4122 struct task_struct *task = task_event->task;
4123 int ret, size = task_event->event_id.header.size;
4124
4125 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
4126
4127 ret = perf_output_begin(&handle, event,
4128 task_event->event_id.header.size);
4129 if (ret)
4130 goto out;
4131
4132 task_event->event_id.pid = perf_event_pid(event, task);
4133 task_event->event_id.ppid = perf_event_pid(event, current);
4134
4135 task_event->event_id.tid = perf_event_tid(event, task);
4136 task_event->event_id.ptid = perf_event_tid(event, current);
4137
4138 perf_output_put(&handle, task_event->event_id);
4139
4140 perf_event__output_id_sample(event, &handle, &sample);
4141
4142 perf_output_end(&handle);
4143out:
4144 task_event->event_id.header.size = size;
4145}
4146
4147static int perf_event_task_match(struct perf_event *event)
4148{
4149 if (event->state < PERF_EVENT_STATE_INACTIVE)
4150 return 0;
4151
4152 if (!event_filter_match(event))
4153 return 0;
4154
4155 if (event->attr.comm || event->attr.mmap ||
4156 event->attr.mmap_data || event->attr.task)
4157 return 1;
4158
4159 return 0;
4160}
4161
4162static void perf_event_task_ctx(struct perf_event_context *ctx,
4163 struct perf_task_event *task_event)
4164{
4165 struct perf_event *event;
4166
4167 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4168 if (perf_event_task_match(event))
4169 perf_event_task_output(event, task_event);
4170 }
4171}
4172
4173static void perf_event_task_event(struct perf_task_event *task_event)
4174{
4175 struct perf_cpu_context *cpuctx;
4176 struct perf_event_context *ctx;
4177 struct pmu *pmu;
4178 int ctxn;
4179
4180 rcu_read_lock();
4181 list_for_each_entry_rcu(pmu, &pmus, entry) {
4182 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
4183 if (cpuctx->active_pmu != pmu)
4184 goto next;
4185 perf_event_task_ctx(&cpuctx->ctx, task_event);
4186
4187 ctx = task_event->task_ctx;
4188 if (!ctx) {
4189 ctxn = pmu->task_ctx_nr;
4190 if (ctxn < 0)
4191 goto next;
4192 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
4193 }
4194 if (ctx)
4195 perf_event_task_ctx(ctx, task_event);
4196next:
4197 put_cpu_ptr(pmu->pmu_cpu_context);
4198 }
4199 rcu_read_unlock();
4200}
4201
4202static void perf_event_task(struct task_struct *task,
4203 struct perf_event_context *task_ctx,
4204 int new)
4205{
4206 struct perf_task_event task_event;
4207
4208 if (!atomic_read(&nr_comm_events) &&
4209 !atomic_read(&nr_mmap_events) &&
4210 !atomic_read(&nr_task_events))
4211 return;
4212
4213 task_event = (struct perf_task_event){
4214 .task = task,
4215 .task_ctx = task_ctx,
4216 .event_id = {
4217 .header = {
4218 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
4219 .misc = 0,
4220 .size = sizeof(task_event.event_id),
4221 },
4222 /* .pid */
4223 /* .ppid */
4224 /* .tid */
4225 /* .ptid */
4226 .time = perf_clock(),
4227 },
4228 };
4229
4230 perf_event_task_event(&task_event);
4231}
4232
4233void perf_event_fork(struct task_struct *task)
4234{
4235 perf_event_task(task, NULL, 1);
4236}
4237
4238/*
4239 * comm tracking
4240 */
4241
4242struct perf_comm_event {
4243 struct task_struct *task;
4244 char *comm;
4245 int comm_size;
4246
4247 struct {
4248 struct perf_event_header header;
4249
4250 u32 pid;
4251 u32 tid;
4252 } event_id;
4253};
4254
4255static void perf_event_comm_output(struct perf_event *event,
4256 struct perf_comm_event *comm_event)
4257{
4258 struct perf_output_handle handle;
4259 struct perf_sample_data sample;
4260 int size = comm_event->event_id.header.size;
4261 int ret;
4262
4263 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
4264 ret = perf_output_begin(&handle, event,
4265 comm_event->event_id.header.size);
4266
4267 if (ret)
4268 goto out;
4269
4270 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
4271 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
4272
4273 perf_output_put(&handle, comm_event->event_id);
4274 __output_copy(&handle, comm_event->comm,
4275 comm_event->comm_size);
4276
4277 perf_event__output_id_sample(event, &handle, &sample);
4278
4279 perf_output_end(&handle);
4280out:
4281 comm_event->event_id.header.size = size;
4282}
4283
4284static int perf_event_comm_match(struct perf_event *event)
4285{
4286 if (event->state < PERF_EVENT_STATE_INACTIVE)
4287 return 0;
4288
4289 if (!event_filter_match(event))
4290 return 0;
4291
4292 if (event->attr.comm)
4293 return 1;
4294
4295 return 0;
4296}
4297
4298static void perf_event_comm_ctx(struct perf_event_context *ctx,
4299 struct perf_comm_event *comm_event)
4300{
4301 struct perf_event *event;
4302
4303 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4304 if (perf_event_comm_match(event))
4305 perf_event_comm_output(event, comm_event);
4306 }
4307}
4308
4309static void perf_event_comm_event(struct perf_comm_event *comm_event)
4310{
4311 struct perf_cpu_context *cpuctx;
4312 struct perf_event_context *ctx;
4313 char comm[TASK_COMM_LEN];
4314 unsigned int size;
4315 struct pmu *pmu;
4316 int ctxn;
4317
4318 memset(comm, 0, sizeof(comm));
4319 strlcpy(comm, comm_event->task->comm, sizeof(comm));
4320 size = ALIGN(strlen(comm)+1, sizeof(u64));
4321
4322 comm_event->comm = comm;
4323 comm_event->comm_size = size;
4324
4325 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
4326 rcu_read_lock();
4327 list_for_each_entry_rcu(pmu, &pmus, entry) {
4328 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
4329 if (cpuctx->active_pmu != pmu)
4330 goto next;
4331 perf_event_comm_ctx(&cpuctx->ctx, comm_event);
4332
4333 ctxn = pmu->task_ctx_nr;
4334 if (ctxn < 0)
4335 goto next;
4336
4337 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
4338 if (ctx)
4339 perf_event_comm_ctx(ctx, comm_event);
4340next:
4341 put_cpu_ptr(pmu->pmu_cpu_context);
4342 }
4343 rcu_read_unlock();
4344}
4345
4346void perf_event_comm(struct task_struct *task)
4347{
4348 struct perf_comm_event comm_event;
4349 struct perf_event_context *ctx;
4350 int ctxn;
4351
4352 for_each_task_context_nr(ctxn) {
4353 ctx = task->perf_event_ctxp[ctxn];
4354 if (!ctx)
4355 continue;
4356
4357 perf_event_enable_on_exec(ctx);
4358 }
4359
4360 if (!atomic_read(&nr_comm_events))
4361 return;
4362
4363 comm_event = (struct perf_comm_event){
4364 .task = task,
4365 /* .comm */
4366 /* .comm_size */
4367 .event_id = {
4368 .header = {
4369 .type = PERF_RECORD_COMM,
4370 .misc = 0,
4371 /* .size */
4372 },
4373 /* .pid */
4374 /* .tid */
4375 },
4376 };
4377
4378 perf_event_comm_event(&comm_event);
4379}
4380
4381/*
4382 * mmap tracking
4383 */
4384
4385struct perf_mmap_event {
4386 struct vm_area_struct *vma;
4387
4388 const char *file_name;
4389 int file_size;
4390
4391 struct {
4392 struct perf_event_header header;
4393
4394 u32 pid;
4395 u32 tid;
4396 u64 start;
4397 u64 len;
4398 u64 pgoff;
4399 } event_id;
4400};
4401
4402static void perf_event_mmap_output(struct perf_event *event,
4403 struct perf_mmap_event *mmap_event)
4404{
4405 struct perf_output_handle handle;
4406 struct perf_sample_data sample;
4407 int size = mmap_event->event_id.header.size;
4408 int ret;
4409
4410 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
4411 ret = perf_output_begin(&handle, event,
4412 mmap_event->event_id.header.size);
4413 if (ret)
4414 goto out;
4415
4416 mmap_event->event_id.pid = perf_event_pid(event, current);
4417 mmap_event->event_id.tid = perf_event_tid(event, current);
4418
4419 perf_output_put(&handle, mmap_event->event_id);
4420 __output_copy(&handle, mmap_event->file_name,
4421 mmap_event->file_size);
4422
4423 perf_event__output_id_sample(event, &handle, &sample);
4424
4425 perf_output_end(&handle);
4426out:
4427 mmap_event->event_id.header.size = size;
4428}
4429
4430static int perf_event_mmap_match(struct perf_event *event,
4431 struct perf_mmap_event *mmap_event,
4432 int executable)
4433{
4434 if (event->state < PERF_EVENT_STATE_INACTIVE)
4435 return 0;
4436
4437 if (!event_filter_match(event))
4438 return 0;
4439
4440 if ((!executable && event->attr.mmap_data) ||
4441 (executable && event->attr.mmap))
4442 return 1;
4443
4444 return 0;
4445}
4446
4447static void perf_event_mmap_ctx(struct perf_event_context *ctx,
4448 struct perf_mmap_event *mmap_event,
4449 int executable)
4450{
4451 struct perf_event *event;
4452
4453 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4454 if (perf_event_mmap_match(event, mmap_event, executable))
4455 perf_event_mmap_output(event, mmap_event);
4456 }
4457}
4458
4459static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
4460{
4461 struct perf_cpu_context *cpuctx;
4462 struct perf_event_context *ctx;
4463 struct vm_area_struct *vma = mmap_event->vma;
4464 struct file *file = vma->vm_file;
4465 unsigned int size;
4466 char tmp[16];
4467 char *buf = NULL;
4468 const char *name;
4469 struct pmu *pmu;
4470 int ctxn;
4471
4472 memset(tmp, 0, sizeof(tmp));
4473
4474 if (file) {
4475 /*
4476 * d_path works from the end of the rb backwards, so we
4477 * need to add enough zero bytes after the string to handle
4478 * the 64bit alignment we do later.
4479 */
4480 buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
4481 if (!buf) {
4482 name = strncpy(tmp, "//enomem", sizeof(tmp));
4483 goto got_name;
4484 }
4485 name = d_path(&file->f_path, buf, PATH_MAX);
4486 if (IS_ERR(name)) {
4487 name = strncpy(tmp, "//toolong", sizeof(tmp));
4488 goto got_name;
4489 }
4490 } else {
4491 if (arch_vma_name(mmap_event->vma)) {
4492 name = strncpy(tmp, arch_vma_name(mmap_event->vma),
4493 sizeof(tmp));
4494 goto got_name;
4495 }
4496
4497 if (!vma->vm_mm) {
4498 name = strncpy(tmp, "[vdso]", sizeof(tmp));
4499 goto got_name;
4500 } else if (vma->vm_start <= vma->vm_mm->start_brk &&
4501 vma->vm_end >= vma->vm_mm->brk) {
4502 name = strncpy(tmp, "[heap]", sizeof(tmp));
4503 goto got_name;
4504 } else if (vma->vm_start <= vma->vm_mm->start_stack &&
4505 vma->vm_end >= vma->vm_mm->start_stack) {
4506 name = strncpy(tmp, "[stack]", sizeof(tmp));
4507 goto got_name;
4508 }
4509
4510 name = strncpy(tmp, "//anon", sizeof(tmp));
4511 goto got_name;
4512 }
4513
4514got_name:
4515 size = ALIGN(strlen(name)+1, sizeof(u64));
4516
4517 mmap_event->file_name = name;
4518 mmap_event->file_size = size;
4519
4520 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
4521
4522 rcu_read_lock();
4523 list_for_each_entry_rcu(pmu, &pmus, entry) {
4524 cpuctx = get_cpu_ptr(pmu->pmu_cpu_context);
4525 if (cpuctx->active_pmu != pmu)
4526 goto next;
4527 perf_event_mmap_ctx(&cpuctx->ctx, mmap_event,
4528 vma->vm_flags & VM_EXEC);
4529
4530 ctxn = pmu->task_ctx_nr;
4531 if (ctxn < 0)
4532 goto next;
4533
4534 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
4535 if (ctx) {
4536 perf_event_mmap_ctx(ctx, mmap_event,
4537 vma->vm_flags & VM_EXEC);
4538 }
4539next:
4540 put_cpu_ptr(pmu->pmu_cpu_context);
4541 }
4542 rcu_read_unlock();
4543
4544 kfree(buf);
4545}
4546
4547void perf_event_mmap(struct vm_area_struct *vma)
4548{
4549 struct perf_mmap_event mmap_event;
4550
4551 if (!atomic_read(&nr_mmap_events))
4552 return;
4553
4554 mmap_event = (struct perf_mmap_event){
4555 .vma = vma,
4556 /* .file_name */
4557 /* .file_size */
4558 .event_id = {
4559 .header = {
4560 .type = PERF_RECORD_MMAP,
4561 .misc = PERF_RECORD_MISC_USER,
4562 /* .size */
4563 },
4564 /* .pid */
4565 /* .tid */
4566 .start = vma->vm_start,
4567 .len = vma->vm_end - vma->vm_start,
4568 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
4569 },
4570 };
4571
4572 perf_event_mmap_event(&mmap_event);
4573}
4574
4575/*
4576 * IRQ throttle logging
4577 */
4578
4579static void perf_log_throttle(struct perf_event *event, int enable)
4580{
4581 struct perf_output_handle handle;
4582 struct perf_sample_data sample;
4583 int ret;
4584
4585 struct {
4586 struct perf_event_header header;
4587 u64 time;
4588 u64 id;
4589 u64 stream_id;
4590 } throttle_event = {
4591 .header = {
4592 .type = PERF_RECORD_THROTTLE,
4593 .misc = 0,
4594 .size = sizeof(throttle_event),
4595 },
4596 .time = perf_clock(),
4597 .id = primary_event_id(event),
4598 .stream_id = event->id,
4599 };
4600
4601 if (enable)
4602 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
4603
4604 perf_event_header__init_id(&throttle_event.header, &sample, event);
4605
4606 ret = perf_output_begin(&handle, event,
4607 throttle_event.header.size);
4608 if (ret)
4609 return;
4610
4611 perf_output_put(&handle, throttle_event);
4612 perf_event__output_id_sample(event, &handle, &sample);
4613 perf_output_end(&handle);
4614}
4615
4616/*
4617 * Generic event overflow handling, sampling.
4618 */
4619
4620static int __perf_event_overflow(struct perf_event *event,
4621 int throttle, struct perf_sample_data *data,
4622 struct pt_regs *regs)
4623{
4624 int events = atomic_read(&event->event_limit);
4625 struct hw_perf_event *hwc = &event->hw;
4626 int ret = 0;
4627
4628 /*
4629 * Non-sampling counters might still use the PMI to fold short
4630 * hardware counters, ignore those.
4631 */
4632 if (unlikely(!is_sampling_event(event)))
4633 return 0;
4634
4635 if (unlikely(hwc->interrupts >= max_samples_per_tick)) {
4636 if (throttle) {
4637 hwc->interrupts = MAX_INTERRUPTS;
4638 perf_log_throttle(event, 0);
4639 ret = 1;
4640 }
4641 } else
4642 hwc->interrupts++;
4643
4644 if (event->attr.freq) {
4645 u64 now = perf_clock();
4646 s64 delta = now - hwc->freq_time_stamp;
4647
4648 hwc->freq_time_stamp = now;
4649
4650 if (delta > 0 && delta < 2*TICK_NSEC)
4651 perf_adjust_period(event, delta, hwc->last_period);
4652 }
4653
4654 /*
4655 * XXX event_limit might not quite work as expected on inherited
4656 * events
4657 */
4658
4659 event->pending_kill = POLL_IN;
4660 if (events && atomic_dec_and_test(&event->event_limit)) {
4661 ret = 1;
4662 event->pending_kill = POLL_HUP;
4663 event->pending_disable = 1;
4664 irq_work_queue(&event->pending);
4665 }
4666
4667 if (event->overflow_handler)
4668 event->overflow_handler(event, data, regs);
4669 else
4670 perf_event_output(event, data, regs);
4671
4672 if (event->fasync && event->pending_kill) {
4673 event->pending_wakeup = 1;
4674 irq_work_queue(&event->pending);
4675 }
4676
4677 return ret;
4678}
4679
4680int perf_event_overflow(struct perf_event *event,
4681 struct perf_sample_data *data,
4682 struct pt_regs *regs)
4683{
4684 return __perf_event_overflow(event, 1, data, regs);
4685}
4686
4687/*
4688 * Generic software event infrastructure
4689 */
4690
4691struct swevent_htable {
4692 struct swevent_hlist *swevent_hlist;
4693 struct mutex hlist_mutex;
4694 int hlist_refcount;
4695
4696 /* Recursion avoidance in each contexts */
4697 int recursion[PERF_NR_CONTEXTS];
4698};
4699
4700static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
4701
4702/*
4703 * We directly increment event->count and keep a second value in
4704 * event->hw.period_left to count intervals. This period event
4705 * is kept in the range [-sample_period, 0] so that we can use the
4706 * sign as trigger.
4707 */
4708
4709static u64 perf_swevent_set_period(struct perf_event *event)
4710{
4711 struct hw_perf_event *hwc = &event->hw;
4712 u64 period = hwc->last_period;
4713 u64 nr, offset;
4714 s64 old, val;
4715
4716 hwc->last_period = hwc->sample_period;
4717
4718again:
4719 old = val = local64_read(&hwc->period_left);
4720 if (val < 0)
4721 return 0;
4722
4723 nr = div64_u64(period + val, period);
4724 offset = nr * period;
4725 val -= offset;
4726 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
4727 goto again;
4728
4729 return nr;
4730}
4731
4732static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
4733 struct perf_sample_data *data,
4734 struct pt_regs *regs)
4735{
4736 struct hw_perf_event *hwc = &event->hw;
4737 int throttle = 0;
4738
4739 data->period = event->hw.last_period;
4740 if (!overflow)
4741 overflow = perf_swevent_set_period(event);
4742
4743 if (hwc->interrupts == MAX_INTERRUPTS)
4744 return;
4745
4746 for (; overflow; overflow--) {
4747 if (__perf_event_overflow(event, throttle,
4748 data, regs)) {
4749 /*
4750 * We inhibit the overflow from happening when
4751 * hwc->interrupts == MAX_INTERRUPTS.
4752 */
4753 break;
4754 }
4755 throttle = 1;
4756 }
4757}
4758
4759static void perf_swevent_event(struct perf_event *event, u64 nr,
4760 struct perf_sample_data *data,
4761 struct pt_regs *regs)
4762{
4763 struct hw_perf_event *hwc = &event->hw;
4764
4765 local64_add(nr, &event->count);
4766
4767 if (!regs)
4768 return;
4769
4770 if (!is_sampling_event(event))
4771 return;
4772
4773 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
4774 return perf_swevent_overflow(event, 1, data, regs);
4775
4776 if (local64_add_negative(nr, &hwc->period_left))
4777 return;
4778
4779 perf_swevent_overflow(event, 0, data, regs);
4780}
4781
4782static int perf_exclude_event(struct perf_event *event,
4783 struct pt_regs *regs)
4784{
4785 if (event->hw.state & PERF_HES_STOPPED)
4786 return 1;
4787
4788 if (regs) {
4789 if (event->attr.exclude_user && user_mode(regs))
4790 return 1;
4791
4792 if (event->attr.exclude_kernel && !user_mode(regs))
4793 return 1;
4794 }
4795
4796 return 0;
4797}
4798
4799static int perf_swevent_match(struct perf_event *event,
4800 enum perf_type_id type,
4801 u32 event_id,
4802 struct perf_sample_data *data,
4803 struct pt_regs *regs)
4804{
4805 if (event->attr.type != type)
4806 return 0;
4807
4808 if (event->attr.config != event_id)
4809 return 0;
4810
4811 if (perf_exclude_event(event, regs))
4812 return 0;
4813
4814 return 1;
4815}
4816
4817static inline u64 swevent_hash(u64 type, u32 event_id)
4818{
4819 u64 val = event_id | (type << 32);
4820
4821 return hash_64(val, SWEVENT_HLIST_BITS);
4822}
4823
4824static inline struct hlist_head *
4825__find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
4826{
4827 u64 hash = swevent_hash(type, event_id);
4828
4829 return &hlist->heads[hash];
4830}
4831
4832/* For the read side: events when they trigger */
4833static inline struct hlist_head *
4834find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
4835{
4836 struct swevent_hlist *hlist;
4837
4838 hlist = rcu_dereference(swhash->swevent_hlist);
4839 if (!hlist)
4840 return NULL;
4841
4842 return __find_swevent_head(hlist, type, event_id);
4843}
4844
4845/* For the event head insertion and removal in the hlist */
4846static inline struct hlist_head *
4847find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
4848{
4849 struct swevent_hlist *hlist;
4850 u32 event_id = event->attr.config;
4851 u64 type = event->attr.type;
4852
4853 /*
4854 * Event scheduling is always serialized against hlist allocation
4855 * and release. Which makes the protected version suitable here.
4856 * The context lock guarantees that.
4857 */
4858 hlist = rcu_dereference_protected(swhash->swevent_hlist,
4859 lockdep_is_held(&event->ctx->lock));
4860 if (!hlist)
4861 return NULL;
4862
4863 return __find_swevent_head(hlist, type, event_id);
4864}
4865
4866static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
4867 u64 nr,
4868 struct perf_sample_data *data,
4869 struct pt_regs *regs)
4870{
4871 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
4872 struct perf_event *event;
4873 struct hlist_node *node;
4874 struct hlist_head *head;
4875
4876 rcu_read_lock();
4877 head = find_swevent_head_rcu(swhash, type, event_id);
4878 if (!head)
4879 goto end;
4880
4881 hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
4882 if (perf_swevent_match(event, type, event_id, data, regs))
4883 perf_swevent_event(event, nr, data, regs);
4884 }
4885end:
4886 rcu_read_unlock();
4887}
4888
4889int perf_swevent_get_recursion_context(void)
4890{
4891 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
4892
4893 return get_recursion_context(swhash->recursion);
4894}
4895EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
4896
4897inline void perf_swevent_put_recursion_context(int rctx)
4898{
4899 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
4900
4901 put_recursion_context(swhash->recursion, rctx);
4902}
4903
4904void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
4905{
4906 struct perf_sample_data data;
4907 int rctx;
4908
4909 preempt_disable_notrace();
4910 rctx = perf_swevent_get_recursion_context();
4911 if (rctx < 0)
4912 return;
4913
4914 perf_sample_data_init(&data, addr);
4915
4916 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
4917
4918 perf_swevent_put_recursion_context(rctx);
4919 preempt_enable_notrace();
4920}
4921
4922static void perf_swevent_read(struct perf_event *event)
4923{
4924}
4925
4926static int perf_swevent_add(struct perf_event *event, int flags)
4927{
4928 struct swevent_htable *swhash = &__get_cpu_var(swevent_htable);
4929 struct hw_perf_event *hwc = &event->hw;
4930 struct hlist_head *head;
4931
4932 if (is_sampling_event(event)) {
4933 hwc->last_period = hwc->sample_period;
4934 perf_swevent_set_period(event);
4935 }
4936
4937 hwc->state = !(flags & PERF_EF_START);
4938
4939 head = find_swevent_head(swhash, event);
4940 if (WARN_ON_ONCE(!head))
4941 return -EINVAL;
4942
4943 hlist_add_head_rcu(&event->hlist_entry, head);
4944
4945 return 0;
4946}
4947
4948static void perf_swevent_del(struct perf_event *event, int flags)
4949{
4950 hlist_del_rcu(&event->hlist_entry);
4951}
4952
4953static void perf_swevent_start(struct perf_event *event, int flags)
4954{
4955 event->hw.state = 0;
4956}
4957
4958static void perf_swevent_stop(struct perf_event *event, int flags)
4959{
4960 event->hw.state = PERF_HES_STOPPED;
4961}
4962
4963/* Deref the hlist from the update side */
4964static inline struct swevent_hlist *
4965swevent_hlist_deref(struct swevent_htable *swhash)
4966{
4967 return rcu_dereference_protected(swhash->swevent_hlist,
4968 lockdep_is_held(&swhash->hlist_mutex));
4969}
4970
4971static void swevent_hlist_release(struct swevent_htable *swhash)
4972{
4973 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
4974
4975 if (!hlist)
4976 return;
4977
4978 rcu_assign_pointer(swhash->swevent_hlist, NULL);
4979 kfree_rcu(hlist, rcu_head);
4980}
4981
4982static void swevent_hlist_put_cpu(struct perf_event *event, int cpu)
4983{
4984 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
4985
4986 mutex_lock(&swhash->hlist_mutex);
4987
4988 if (!--swhash->hlist_refcount)
4989 swevent_hlist_release(swhash);
4990
4991 mutex_unlock(&swhash->hlist_mutex);
4992}
4993
4994static void swevent_hlist_put(struct perf_event *event)
4995{
4996 int cpu;
4997
4998 if (event->cpu != -1) {
4999 swevent_hlist_put_cpu(event, event->cpu);
5000 return;
5001 }
5002
5003 for_each_possible_cpu(cpu)
5004 swevent_hlist_put_cpu(event, cpu);
5005}
5006
5007static int swevent_hlist_get_cpu(struct perf_event *event, int cpu)
5008{
5009 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
5010 int err = 0;
5011
5012 mutex_lock(&swhash->hlist_mutex);
5013
5014 if (!swevent_hlist_deref(swhash) && cpu_online(cpu)) {
5015 struct swevent_hlist *hlist;
5016
5017 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
5018 if (!hlist) {
5019 err = -ENOMEM;
5020 goto exit;
5021 }
5022 rcu_assign_pointer(swhash->swevent_hlist, hlist);
5023 }
5024 swhash->hlist_refcount++;
5025exit:
5026 mutex_unlock(&swhash->hlist_mutex);
5027
5028 return err;
5029}
5030
5031static int swevent_hlist_get(struct perf_event *event)
5032{
5033 int err;
5034 int cpu, failed_cpu;
5035
5036 if (event->cpu != -1)
5037 return swevent_hlist_get_cpu(event, event->cpu);
5038
5039 get_online_cpus();
5040 for_each_possible_cpu(cpu) {
5041 err = swevent_hlist_get_cpu(event, cpu);
5042 if (err) {
5043 failed_cpu = cpu;
5044 goto fail;
5045 }
5046 }
5047 put_online_cpus();
5048
5049 return 0;
5050fail:
5051 for_each_possible_cpu(cpu) {
5052 if (cpu == failed_cpu)
5053 break;
5054 swevent_hlist_put_cpu(event, cpu);
5055 }
5056
5057 put_online_cpus();
5058 return err;
5059}
5060
5061struct jump_label_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
5062
5063static void sw_perf_event_destroy(struct perf_event *event)
5064{
5065 u64 event_id = event->attr.config;
5066
5067 WARN_ON(event->parent);
5068
5069 jump_label_dec(&perf_swevent_enabled[event_id]);
5070 swevent_hlist_put(event);
5071}
5072
5073static int perf_swevent_init(struct perf_event *event)
5074{
5075 int event_id = event->attr.config;
5076
5077 if (event->attr.type != PERF_TYPE_SOFTWARE)
5078 return -ENOENT;
5079
5080 switch (event_id) {
5081 case PERF_COUNT_SW_CPU_CLOCK:
5082 case PERF_COUNT_SW_TASK_CLOCK:
5083 return -ENOENT;
5084
5085 default:
5086 break;
5087 }
5088
5089 if (event_id >= PERF_COUNT_SW_MAX)
5090 return -ENOENT;
5091
5092 if (!event->parent) {
5093 int err;
5094
5095 err = swevent_hlist_get(event);
5096 if (err)
5097 return err;
5098
5099 jump_label_inc(&perf_swevent_enabled[event_id]);
5100 event->destroy = sw_perf_event_destroy;
5101 }
5102
5103 return 0;
5104}
5105
5106static struct pmu perf_swevent = {
5107 .task_ctx_nr = perf_sw_context,
5108
5109 .event_init = perf_swevent_init,
5110 .add = perf_swevent_add,
5111 .del = perf_swevent_del,
5112 .start = perf_swevent_start,
5113 .stop = perf_swevent_stop,
5114 .read = perf_swevent_read,
5115};
5116
5117#ifdef CONFIG_EVENT_TRACING
5118
5119static int perf_tp_filter_match(struct perf_event *event,
5120 struct perf_sample_data *data)
5121{
5122 void *record = data->raw->data;
5123
5124 if (likely(!event->filter) || filter_match_preds(event->filter, record))
5125 return 1;
5126 return 0;
5127}
5128
5129static int perf_tp_event_match(struct perf_event *event,
5130 struct perf_sample_data *data,
5131 struct pt_regs *regs)
5132{
5133 if (event->hw.state & PERF_HES_STOPPED)
5134 return 0;
5135 /*
5136 * All tracepoints are from kernel-space.
5137 */
5138 if (event->attr.exclude_kernel)
5139 return 0;
5140
5141 if (!perf_tp_filter_match(event, data))
5142 return 0;
5143
5144 return 1;
5145}
5146
5147void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
5148 struct pt_regs *regs, struct hlist_head *head, int rctx)
5149{
5150 struct perf_sample_data data;
5151 struct perf_event *event;
5152 struct hlist_node *node;
5153
5154 struct perf_raw_record raw = {
5155 .size = entry_size,
5156 .data = record,
5157 };
5158
5159 perf_sample_data_init(&data, addr);
5160 data.raw = &raw;
5161
5162 hlist_for_each_entry_rcu(event, node, head, hlist_entry) {
5163 if (perf_tp_event_match(event, &data, regs))
5164 perf_swevent_event(event, count, &data, regs);
5165 }
5166
5167 perf_swevent_put_recursion_context(rctx);
5168}
5169EXPORT_SYMBOL_GPL(perf_tp_event);
5170
5171static void tp_perf_event_destroy(struct perf_event *event)
5172{
5173 perf_trace_destroy(event);
5174}
5175
5176static int perf_tp_event_init(struct perf_event *event)
5177{
5178 int err;
5179
5180 if (event->attr.type != PERF_TYPE_TRACEPOINT)
5181 return -ENOENT;
5182
5183 err = perf_trace_init(event);
5184 if (err)
5185 return err;
5186
5187 event->destroy = tp_perf_event_destroy;
5188
5189 return 0;
5190}
5191
5192static struct pmu perf_tracepoint = {
5193 .task_ctx_nr = perf_sw_context,
5194
5195 .event_init = perf_tp_event_init,
5196 .add = perf_trace_add,
5197 .del = perf_trace_del,
5198 .start = perf_swevent_start,
5199 .stop = perf_swevent_stop,
5200 .read = perf_swevent_read,
5201};
5202
5203static inline void perf_tp_register(void)
5204{
5205 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
5206}
5207
5208static int perf_event_set_filter(struct perf_event *event, void __user *arg)
5209{
5210 char *filter_str;
5211 int ret;
5212
5213 if (event->attr.type != PERF_TYPE_TRACEPOINT)
5214 return -EINVAL;
5215
5216 filter_str = strndup_user(arg, PAGE_SIZE);
5217 if (IS_ERR(filter_str))
5218 return PTR_ERR(filter_str);
5219
5220 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
5221
5222 kfree(filter_str);
5223 return ret;
5224}
5225
5226static void perf_event_free_filter(struct perf_event *event)
5227{
5228 ftrace_profile_free_filter(event);
5229}
5230
5231#else
5232
5233static inline void perf_tp_register(void)
5234{
5235}
5236
5237static int perf_event_set_filter(struct perf_event *event, void __user *arg)
5238{
5239 return -ENOENT;
5240}
5241
5242static void perf_event_free_filter(struct perf_event *event)
5243{
5244}
5245
5246#endif /* CONFIG_EVENT_TRACING */
5247
5248#ifdef CONFIG_HAVE_HW_BREAKPOINT
5249void perf_bp_event(struct perf_event *bp, void *data)
5250{
5251 struct perf_sample_data sample;
5252 struct pt_regs *regs = data;
5253
5254 perf_sample_data_init(&sample, bp->attr.bp_addr);
5255
5256 if (!bp->hw.state && !perf_exclude_event(bp, regs))
5257 perf_swevent_event(bp, 1, &sample, regs);
5258}
5259#endif
5260
5261/*
5262 * hrtimer based swevent callback
5263 */
5264
5265static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
5266{
5267 enum hrtimer_restart ret = HRTIMER_RESTART;
5268 struct perf_sample_data data;
5269 struct pt_regs *regs;
5270 struct perf_event *event;
5271 u64 period;
5272
5273 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
5274
5275 if (event->state != PERF_EVENT_STATE_ACTIVE)
5276 return HRTIMER_NORESTART;
5277
5278 event->pmu->read(event);
5279
5280 perf_sample_data_init(&data, 0);
5281 data.period = event->hw.last_period;
5282 regs = get_irq_regs();
5283
5284 if (regs && !perf_exclude_event(event, regs)) {
5285 if (!(event->attr.exclude_idle && current->pid == 0))
5286 if (perf_event_overflow(event, &data, regs))
5287 ret = HRTIMER_NORESTART;
5288 }
5289
5290 period = max_t(u64, 10000, event->hw.sample_period);
5291 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
5292
5293 return ret;
5294}
5295
5296static void perf_swevent_start_hrtimer(struct perf_event *event)
5297{
5298 struct hw_perf_event *hwc = &event->hw;
5299 s64 period;
5300
5301 if (!is_sampling_event(event))
5302 return;
5303
5304 period = local64_read(&hwc->period_left);
5305 if (period) {
5306 if (period < 0)
5307 period = 10000;
5308
5309 local64_set(&hwc->period_left, 0);
5310 } else {
5311 period = max_t(u64, 10000, hwc->sample_period);
5312 }
5313 __hrtimer_start_range_ns(&hwc->hrtimer,
5314 ns_to_ktime(period), 0,
5315 HRTIMER_MODE_REL_PINNED, 0);
5316}
5317
5318static void perf_swevent_cancel_hrtimer(struct perf_event *event)
5319{
5320 struct hw_perf_event *hwc = &event->hw;
5321
5322 if (is_sampling_event(event)) {
5323 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
5324 local64_set(&hwc->period_left, ktime_to_ns(remaining));
5325
5326 hrtimer_cancel(&hwc->hrtimer);
5327 }
5328}
5329
5330static void perf_swevent_init_hrtimer(struct perf_event *event)
5331{
5332 struct hw_perf_event *hwc = &event->hw;
5333
5334 if (!is_sampling_event(event))
5335 return;
5336
5337 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
5338 hwc->hrtimer.function = perf_swevent_hrtimer;
5339
5340 /*
5341 * Since hrtimers have a fixed rate, we can do a static freq->period
5342 * mapping and avoid the whole period adjust feedback stuff.
5343 */
5344 if (event->attr.freq) {
5345 long freq = event->attr.sample_freq;
5346
5347 event->attr.sample_period = NSEC_PER_SEC / freq;
5348 hwc->sample_period = event->attr.sample_period;
5349 local64_set(&hwc->period_left, hwc->sample_period);
5350 event->attr.freq = 0;
5351 }
5352}
5353
5354/*
5355 * Software event: cpu wall time clock
5356 */
5357
5358static void cpu_clock_event_update(struct perf_event *event)
5359{
5360 s64 prev;
5361 u64 now;
5362
5363 now = local_clock();
5364 prev = local64_xchg(&event->hw.prev_count, now);
5365 local64_add(now - prev, &event->count);
5366}
5367
5368static void cpu_clock_event_start(struct perf_event *event, int flags)
5369{
5370 local64_set(&event->hw.prev_count, local_clock());
5371 perf_swevent_start_hrtimer(event);
5372}
5373
5374static void cpu_clock_event_stop(struct perf_event *event, int flags)
5375{
5376 perf_swevent_cancel_hrtimer(event);
5377 cpu_clock_event_update(event);
5378}
5379
5380static int cpu_clock_event_add(struct perf_event *event, int flags)
5381{
5382 if (flags & PERF_EF_START)
5383 cpu_clock_event_start(event, flags);
5384
5385 return 0;
5386}
5387
5388static void cpu_clock_event_del(struct perf_event *event, int flags)
5389{
5390 cpu_clock_event_stop(event, flags);
5391}
5392
5393static void cpu_clock_event_read(struct perf_event *event)
5394{
5395 cpu_clock_event_update(event);
5396}
5397
5398static int cpu_clock_event_init(struct perf_event *event)
5399{
5400 if (event->attr.type != PERF_TYPE_SOFTWARE)
5401 return -ENOENT;
5402
5403 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
5404 return -ENOENT;
5405
5406 perf_swevent_init_hrtimer(event);
5407
5408 return 0;
5409}
5410
5411static struct pmu perf_cpu_clock = {
5412 .task_ctx_nr = perf_sw_context,
5413
5414 .event_init = cpu_clock_event_init,
5415 .add = cpu_clock_event_add,
5416 .del = cpu_clock_event_del,
5417 .start = cpu_clock_event_start,
5418 .stop = cpu_clock_event_stop,
5419 .read = cpu_clock_event_read,
5420};
5421
5422/*
5423 * Software event: task time clock
5424 */
5425
5426static void task_clock_event_update(struct perf_event *event, u64 now)
5427{
5428 u64 prev;
5429 s64 delta;
5430
5431 prev = local64_xchg(&event->hw.prev_count, now);
5432 delta = now - prev;
5433 local64_add(delta, &event->count);
5434}
5435
5436static void task_clock_event_start(struct perf_event *event, int flags)
5437{
5438 local64_set(&event->hw.prev_count, event->ctx->time);
5439 perf_swevent_start_hrtimer(event);
5440}
5441
5442static void task_clock_event_stop(struct perf_event *event, int flags)
5443{
5444 perf_swevent_cancel_hrtimer(event);
5445 task_clock_event_update(event, event->ctx->time);
5446}
5447
5448static int task_clock_event_add(struct perf_event *event, int flags)
5449{
5450 if (flags & PERF_EF_START)
5451 task_clock_event_start(event, flags);
5452
5453 return 0;
5454}
5455
5456static void task_clock_event_del(struct perf_event *event, int flags)
5457{
5458 task_clock_event_stop(event, PERF_EF_UPDATE);
5459}
5460
5461static void task_clock_event_read(struct perf_event *event)
5462{
5463 u64 now = perf_clock();
5464 u64 delta = now - event->ctx->timestamp;
5465 u64 time = event->ctx->time + delta;
5466
5467 task_clock_event_update(event, time);
5468}
5469
5470static int task_clock_event_init(struct perf_event *event)
5471{
5472 if (event->attr.type != PERF_TYPE_SOFTWARE)
5473 return -ENOENT;
5474
5475 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
5476 return -ENOENT;
5477
5478 perf_swevent_init_hrtimer(event);
5479
5480 return 0;
5481}
5482
5483static struct pmu perf_task_clock = {
5484 .task_ctx_nr = perf_sw_context,
5485
5486 .event_init = task_clock_event_init,
5487 .add = task_clock_event_add,
5488 .del = task_clock_event_del,
5489 .start = task_clock_event_start,
5490 .stop = task_clock_event_stop,
5491 .read = task_clock_event_read,
5492};
5493
5494static void perf_pmu_nop_void(struct pmu *pmu)
5495{
5496}
5497
5498static int perf_pmu_nop_int(struct pmu *pmu)
5499{
5500 return 0;
5501}
5502
5503static void perf_pmu_start_txn(struct pmu *pmu)
5504{
5505 perf_pmu_disable(pmu);
5506}
5507
5508static int perf_pmu_commit_txn(struct pmu *pmu)
5509{
5510 perf_pmu_enable(pmu);
5511 return 0;
5512}
5513
5514static void perf_pmu_cancel_txn(struct pmu *pmu)
5515{
5516 perf_pmu_enable(pmu);
5517}
5518
5519/*
5520 * Ensures all contexts with the same task_ctx_nr have the same
5521 * pmu_cpu_context too.
5522 */
5523static void *find_pmu_context(int ctxn)
5524{
5525 struct pmu *pmu;
5526
5527 if (ctxn < 0)
5528 return NULL;
5529
5530 list_for_each_entry(pmu, &pmus, entry) {
5531 if (pmu->task_ctx_nr == ctxn)
5532 return pmu->pmu_cpu_context;
5533 }
5534
5535 return NULL;
5536}
5537
5538static void update_pmu_context(struct pmu *pmu, struct pmu *old_pmu)
5539{
5540 int cpu;
5541
5542 for_each_possible_cpu(cpu) {
5543 struct perf_cpu_context *cpuctx;
5544
5545 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
5546
5547 if (cpuctx->active_pmu == old_pmu)
5548 cpuctx->active_pmu = pmu;
5549 }
5550}
5551
5552static void free_pmu_context(struct pmu *pmu)
5553{
5554 struct pmu *i;
5555
5556 mutex_lock(&pmus_lock);
5557 /*
5558 * Like a real lame refcount.
5559 */
5560 list_for_each_entry(i, &pmus, entry) {
5561 if (i->pmu_cpu_context == pmu->pmu_cpu_context) {
5562 update_pmu_context(i, pmu);
5563 goto out;
5564 }
5565 }
5566
5567 free_percpu(pmu->pmu_cpu_context);
5568out:
5569 mutex_unlock(&pmus_lock);
5570}
5571static struct idr pmu_idr;
5572
5573static ssize_t
5574type_show(struct device *dev, struct device_attribute *attr, char *page)
5575{
5576 struct pmu *pmu = dev_get_drvdata(dev);
5577
5578 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
5579}
5580
5581static struct device_attribute pmu_dev_attrs[] = {
5582 __ATTR_RO(type),
5583 __ATTR_NULL,
5584};
5585
5586static int pmu_bus_running;
5587static struct bus_type pmu_bus = {
5588 .name = "event_source",
5589 .dev_attrs = pmu_dev_attrs,
5590};
5591
5592static void pmu_dev_release(struct device *dev)
5593{
5594 kfree(dev);
5595}
5596
5597static int pmu_dev_alloc(struct pmu *pmu)
5598{
5599 int ret = -ENOMEM;
5600
5601 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
5602 if (!pmu->dev)
5603 goto out;
5604
5605 device_initialize(pmu->dev);
5606 ret = dev_set_name(pmu->dev, "%s", pmu->name);
5607 if (ret)
5608 goto free_dev;
5609
5610 dev_set_drvdata(pmu->dev, pmu);
5611 pmu->dev->bus = &pmu_bus;
5612 pmu->dev->release = pmu_dev_release;
5613 ret = device_add(pmu->dev);
5614 if (ret)
5615 goto free_dev;
5616
5617out:
5618 return ret;
5619
5620free_dev:
5621 put_device(pmu->dev);
5622 goto out;
5623}
5624
5625static struct lock_class_key cpuctx_mutex;
5626static struct lock_class_key cpuctx_lock;
5627
5628int perf_pmu_register(struct pmu *pmu, char *name, int type)
5629{
5630 int cpu, ret;
5631
5632 mutex_lock(&pmus_lock);
5633 ret = -ENOMEM;
5634 pmu->pmu_disable_count = alloc_percpu(int);
5635 if (!pmu->pmu_disable_count)
5636 goto unlock;
5637
5638 pmu->type = -1;
5639 if (!name)
5640 goto skip_type;
5641 pmu->name = name;
5642
5643 if (type < 0) {
5644 int err = idr_pre_get(&pmu_idr, GFP_KERNEL);
5645 if (!err)
5646 goto free_pdc;
5647
5648 err = idr_get_new_above(&pmu_idr, pmu, PERF_TYPE_MAX, &type);
5649 if (err) {
5650 ret = err;
5651 goto free_pdc;
5652 }
5653 }
5654 pmu->type = type;
5655
5656 if (pmu_bus_running) {
5657 ret = pmu_dev_alloc(pmu);
5658 if (ret)
5659 goto free_idr;
5660 }
5661
5662skip_type:
5663 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
5664 if (pmu->pmu_cpu_context)
5665 goto got_cpu_context;
5666
5667 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
5668 if (!pmu->pmu_cpu_context)
5669 goto free_dev;
5670
5671 for_each_possible_cpu(cpu) {
5672 struct perf_cpu_context *cpuctx;
5673
5674 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
5675 __perf_event_init_context(&cpuctx->ctx);
5676 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
5677 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
5678 cpuctx->ctx.type = cpu_context;
5679 cpuctx->ctx.pmu = pmu;
5680 cpuctx->jiffies_interval = 1;
5681 INIT_LIST_HEAD(&cpuctx->rotation_list);
5682 cpuctx->active_pmu = pmu;
5683 }
5684
5685got_cpu_context:
5686 if (!pmu->start_txn) {
5687 if (pmu->pmu_enable) {
5688 /*
5689 * If we have pmu_enable/pmu_disable calls, install
5690 * transaction stubs that use that to try and batch
5691 * hardware accesses.
5692 */
5693 pmu->start_txn = perf_pmu_start_txn;
5694 pmu->commit_txn = perf_pmu_commit_txn;
5695 pmu->cancel_txn = perf_pmu_cancel_txn;
5696 } else {
5697 pmu->start_txn = perf_pmu_nop_void;
5698 pmu->commit_txn = perf_pmu_nop_int;
5699 pmu->cancel_txn = perf_pmu_nop_void;
5700 }
5701 }
5702
5703 if (!pmu->pmu_enable) {
5704 pmu->pmu_enable = perf_pmu_nop_void;
5705 pmu->pmu_disable = perf_pmu_nop_void;
5706 }
5707
5708 list_add_rcu(&pmu->entry, &pmus);
5709 ret = 0;
5710unlock:
5711 mutex_unlock(&pmus_lock);
5712
5713 return ret;
5714
5715free_dev:
5716 device_del(pmu->dev);
5717 put_device(pmu->dev);
5718
5719free_idr:
5720 if (pmu->type >= PERF_TYPE_MAX)
5721 idr_remove(&pmu_idr, pmu->type);
5722
5723free_pdc:
5724 free_percpu(pmu->pmu_disable_count);
5725 goto unlock;
5726}
5727
5728void perf_pmu_unregister(struct pmu *pmu)
5729{
5730 mutex_lock(&pmus_lock);
5731 list_del_rcu(&pmu->entry);
5732 mutex_unlock(&pmus_lock);
5733
5734 /*
5735 * We dereference the pmu list under both SRCU and regular RCU, so
5736 * synchronize against both of those.
5737 */
5738 synchronize_srcu(&pmus_srcu);
5739 synchronize_rcu();
5740
5741 free_percpu(pmu->pmu_disable_count);
5742 if (pmu->type >= PERF_TYPE_MAX)
5743 idr_remove(&pmu_idr, pmu->type);
5744 device_del(pmu->dev);
5745 put_device(pmu->dev);
5746 free_pmu_context(pmu);
5747}
5748
5749struct pmu *perf_init_event(struct perf_event *event)
5750{
5751 struct pmu *pmu = NULL;
5752 int idx;
5753 int ret;
5754
5755 idx = srcu_read_lock(&pmus_srcu);
5756
5757 rcu_read_lock();
5758 pmu = idr_find(&pmu_idr, event->attr.type);
5759 rcu_read_unlock();
5760 if (pmu) {
5761 ret = pmu->event_init(event);
5762 if (ret)
5763 pmu = ERR_PTR(ret);
5764 goto unlock;
5765 }
5766
5767 list_for_each_entry_rcu(pmu, &pmus, entry) {
5768 ret = pmu->event_init(event);
5769 if (!ret)
5770 goto unlock;
5771
5772 if (ret != -ENOENT) {
5773 pmu = ERR_PTR(ret);
5774 goto unlock;
5775 }
5776 }
5777 pmu = ERR_PTR(-ENOENT);
5778unlock:
5779 srcu_read_unlock(&pmus_srcu, idx);
5780
5781 return pmu;
5782}
5783
5784/*
5785 * Allocate and initialize a event structure
5786 */
5787static struct perf_event *
5788perf_event_alloc(struct perf_event_attr *attr, int cpu,
5789 struct task_struct *task,
5790 struct perf_event *group_leader,
5791 struct perf_event *parent_event,
5792 perf_overflow_handler_t overflow_handler,
5793 void *context)
5794{
5795 struct pmu *pmu;
5796 struct perf_event *event;
5797 struct hw_perf_event *hwc;
5798 long err;
5799
5800 if ((unsigned)cpu >= nr_cpu_ids) {
5801 if (!task || cpu != -1)
5802 return ERR_PTR(-EINVAL);
5803 }
5804
5805 event = kzalloc(sizeof(*event), GFP_KERNEL);
5806 if (!event)
5807 return ERR_PTR(-ENOMEM);
5808
5809 /*
5810 * Single events are their own group leaders, with an
5811 * empty sibling list:
5812 */
5813 if (!group_leader)
5814 group_leader = event;
5815
5816 mutex_init(&event->child_mutex);
5817 INIT_LIST_HEAD(&event->child_list);
5818
5819 INIT_LIST_HEAD(&event->group_entry);
5820 INIT_LIST_HEAD(&event->event_entry);
5821 INIT_LIST_HEAD(&event->sibling_list);
5822 init_waitqueue_head(&event->waitq);
5823 init_irq_work(&event->pending, perf_pending_event);
5824
5825 mutex_init(&event->mmap_mutex);
5826
5827 event->cpu = cpu;
5828 event->attr = *attr;
5829 event->group_leader = group_leader;
5830 event->pmu = NULL;
5831 event->oncpu = -1;
5832
5833 event->parent = parent_event;
5834
5835 event->ns = get_pid_ns(current->nsproxy->pid_ns);
5836 event->id = atomic64_inc_return(&perf_event_id);
5837
5838 event->state = PERF_EVENT_STATE_INACTIVE;
5839
5840 if (task) {
5841 event->attach_state = PERF_ATTACH_TASK;
5842#ifdef CONFIG_HAVE_HW_BREAKPOINT
5843 /*
5844 * hw_breakpoint is a bit difficult here..
5845 */
5846 if (attr->type == PERF_TYPE_BREAKPOINT)
5847 event->hw.bp_target = task;
5848#endif
5849 }
5850
5851 if (!overflow_handler && parent_event) {
5852 overflow_handler = parent_event->overflow_handler;
5853 context = parent_event->overflow_handler_context;
5854 }
5855
5856 event->overflow_handler = overflow_handler;
5857 event->overflow_handler_context = context;
5858
5859 if (attr->disabled)
5860 event->state = PERF_EVENT_STATE_OFF;
5861
5862 pmu = NULL;
5863
5864 hwc = &event->hw;
5865 hwc->sample_period = attr->sample_period;
5866 if (attr->freq && attr->sample_freq)
5867 hwc->sample_period = 1;
5868 hwc->last_period = hwc->sample_period;
5869
5870 local64_set(&hwc->period_left, hwc->sample_period);
5871
5872 /*
5873 * we currently do not support PERF_FORMAT_GROUP on inherited events
5874 */
5875 if (attr->inherit && (attr->read_format & PERF_FORMAT_GROUP))
5876 goto done;
5877
5878 pmu = perf_init_event(event);
5879
5880done:
5881 err = 0;
5882 if (!pmu)
5883 err = -EINVAL;
5884 else if (IS_ERR(pmu))
5885 err = PTR_ERR(pmu);
5886
5887 if (err) {
5888 if (event->ns)
5889 put_pid_ns(event->ns);
5890 kfree(event);
5891 return ERR_PTR(err);
5892 }
5893
5894 event->pmu = pmu;
5895
5896 if (!event->parent) {
5897 if (event->attach_state & PERF_ATTACH_TASK)
5898 jump_label_inc(&perf_sched_events);
5899 if (event->attr.mmap || event->attr.mmap_data)
5900 atomic_inc(&nr_mmap_events);
5901 if (event->attr.comm)
5902 atomic_inc(&nr_comm_events);
5903 if (event->attr.task)
5904 atomic_inc(&nr_task_events);
5905 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
5906 err = get_callchain_buffers();
5907 if (err) {
5908 free_event(event);
5909 return ERR_PTR(err);
5910 }
5911 }
5912 }
5913
5914 return event;
5915}
5916
5917static int perf_copy_attr(struct perf_event_attr __user *uattr,
5918 struct perf_event_attr *attr)
5919{
5920 u32 size;
5921 int ret;
5922
5923 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
5924 return -EFAULT;
5925
5926 /*
5927 * zero the full structure, so that a short copy will be nice.
5928 */
5929 memset(attr, 0, sizeof(*attr));
5930
5931 ret = get_user(size, &uattr->size);
5932 if (ret)
5933 return ret;
5934
5935 if (size > PAGE_SIZE) /* silly large */
5936 goto err_size;
5937
5938 if (!size) /* abi compat */
5939 size = PERF_ATTR_SIZE_VER0;
5940
5941 if (size < PERF_ATTR_SIZE_VER0)
5942 goto err_size;
5943
5944 /*
5945 * If we're handed a bigger struct than we know of,
5946 * ensure all the unknown bits are 0 - i.e. new
5947 * user-space does not rely on any kernel feature
5948 * extensions we dont know about yet.
5949 */
5950 if (size > sizeof(*attr)) {
5951 unsigned char __user *addr;
5952 unsigned char __user *end;
5953 unsigned char val;
5954
5955 addr = (void __user *)uattr + sizeof(*attr);
5956 end = (void __user *)uattr + size;
5957
5958 for (; addr < end; addr++) {
5959 ret = get_user(val, addr);
5960 if (ret)
5961 return ret;
5962 if (val)
5963 goto err_size;
5964 }
5965 size = sizeof(*attr);
5966 }
5967
5968 ret = copy_from_user(attr, uattr, size);
5969 if (ret)
5970 return -EFAULT;
5971
5972 if (attr->__reserved_1)
5973 return -EINVAL;
5974
5975 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
5976 return -EINVAL;
5977
5978 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
5979 return -EINVAL;
5980
5981out:
5982 return ret;
5983
5984err_size:
5985 put_user(sizeof(*attr), &uattr->size);
5986 ret = -E2BIG;
5987 goto out;
5988}
5989
5990static int
5991perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
5992{
5993 struct ring_buffer *rb = NULL, *old_rb = NULL;
5994 int ret = -EINVAL;
5995
5996 if (!output_event)
5997 goto set;
5998
5999 /* don't allow circular references */
6000 if (event == output_event)
6001 goto out;
6002
6003 /*
6004 * Don't allow cross-cpu buffers
6005 */
6006 if (output_event->cpu != event->cpu)
6007 goto out;
6008
6009 /*
6010 * If its not a per-cpu rb, it must be the same task.
6011 */
6012 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
6013 goto out;
6014
6015set:
6016 mutex_lock(&event->mmap_mutex);
6017 /* Can't redirect output if we've got an active mmap() */
6018 if (atomic_read(&event->mmap_count))
6019 goto unlock;
6020
6021 if (output_event) {
6022 /* get the rb we want to redirect to */
6023 rb = ring_buffer_get(output_event);
6024 if (!rb)
6025 goto unlock;
6026 }
6027
6028 old_rb = event->rb;
6029 rcu_assign_pointer(event->rb, rb);
6030 ret = 0;
6031unlock:
6032 mutex_unlock(&event->mmap_mutex);
6033
6034 if (old_rb)
6035 ring_buffer_put(old_rb);
6036out:
6037 return ret;
6038}
6039
6040/**
6041 * sys_perf_event_open - open a performance event, associate it to a task/cpu
6042 *
6043 * @attr_uptr: event_id type attributes for monitoring/sampling
6044 * @pid: target pid
6045 * @cpu: target cpu
6046 * @group_fd: group leader event fd
6047 */
6048SYSCALL_DEFINE5(perf_event_open,
6049 struct perf_event_attr __user *, attr_uptr,
6050 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
6051{
6052 struct perf_event *group_leader = NULL, *output_event = NULL;
6053 struct perf_event *event, *sibling;
6054 struct perf_event_attr attr;
6055 struct perf_event_context *ctx;
6056 struct file *event_file = NULL;
6057 struct file *group_file = NULL;
6058 struct task_struct *task = NULL;
6059 struct pmu *pmu;
6060 int event_fd;
6061 int move_group = 0;
6062 int fput_needed = 0;
6063 int err;
6064
6065 /* for future expandability... */
6066 if (flags & ~PERF_FLAG_ALL)
6067 return -EINVAL;
6068
6069 err = perf_copy_attr(attr_uptr, &attr);
6070 if (err)
6071 return err;
6072
6073 if (!attr.exclude_kernel) {
6074 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
6075 return -EACCES;
6076 }
6077
6078 if (attr.freq) {
6079 if (attr.sample_freq > sysctl_perf_event_sample_rate)
6080 return -EINVAL;
6081 }
6082
6083 /*
6084 * In cgroup mode, the pid argument is used to pass the fd
6085 * opened to the cgroup directory in cgroupfs. The cpu argument
6086 * designates the cpu on which to monitor threads from that
6087 * cgroup.
6088 */
6089 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
6090 return -EINVAL;
6091
6092 event_fd = get_unused_fd_flags(O_RDWR);
6093 if (event_fd < 0)
6094 return event_fd;
6095
6096 if (group_fd != -1) {
6097 group_leader = perf_fget_light(group_fd, &fput_needed);
6098 if (IS_ERR(group_leader)) {
6099 err = PTR_ERR(group_leader);
6100 goto err_fd;
6101 }
6102 group_file = group_leader->filp;
6103 if (flags & PERF_FLAG_FD_OUTPUT)
6104 output_event = group_leader;
6105 if (flags & PERF_FLAG_FD_NO_GROUP)
6106 group_leader = NULL;
6107 }
6108
6109 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
6110 task = find_lively_task_by_vpid(pid);
6111 if (IS_ERR(task)) {
6112 err = PTR_ERR(task);
6113 goto err_group_fd;
6114 }
6115 }
6116
6117 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
6118 NULL, NULL);
6119 if (IS_ERR(event)) {
6120 err = PTR_ERR(event);
6121 goto err_task;
6122 }
6123
6124 if (flags & PERF_FLAG_PID_CGROUP) {
6125 err = perf_cgroup_connect(pid, event, &attr, group_leader);
6126 if (err)
6127 goto err_alloc;
6128 /*
6129 * one more event:
6130 * - that has cgroup constraint on event->cpu
6131 * - that may need work on context switch
6132 */
6133 atomic_inc(&per_cpu(perf_cgroup_events, event->cpu));
6134 jump_label_inc(&perf_sched_events);
6135 }
6136
6137 /*
6138 * Special case software events and allow them to be part of
6139 * any hardware group.
6140 */
6141 pmu = event->pmu;
6142
6143 if (group_leader &&
6144 (is_software_event(event) != is_software_event(group_leader))) {
6145 if (is_software_event(event)) {
6146 /*
6147 * If event and group_leader are not both a software
6148 * event, and event is, then group leader is not.
6149 *
6150 * Allow the addition of software events to !software
6151 * groups, this is safe because software events never
6152 * fail to schedule.
6153 */
6154 pmu = group_leader->pmu;
6155 } else if (is_software_event(group_leader) &&
6156 (group_leader->group_flags & PERF_GROUP_SOFTWARE)) {
6157 /*
6158 * In case the group is a pure software group, and we
6159 * try to add a hardware event, move the whole group to
6160 * the hardware context.
6161 */
6162 move_group = 1;
6163 }
6164 }
6165
6166 /*
6167 * Get the target context (task or percpu):
6168 */
6169 ctx = find_get_context(pmu, task, cpu);
6170 if (IS_ERR(ctx)) {
6171 err = PTR_ERR(ctx);
6172 goto err_alloc;
6173 }
6174
6175 if (task) {
6176 put_task_struct(task);
6177 task = NULL;
6178 }
6179
6180 /*
6181 * Look up the group leader (we will attach this event to it):
6182 */
6183 if (group_leader) {
6184 err = -EINVAL;
6185
6186 /*
6187 * Do not allow a recursive hierarchy (this new sibling
6188 * becoming part of another group-sibling):
6189 */
6190 if (group_leader->group_leader != group_leader)
6191 goto err_context;
6192 /*
6193 * Do not allow to attach to a group in a different
6194 * task or CPU context:
6195 */
6196 if (move_group) {
6197 if (group_leader->ctx->type != ctx->type)
6198 goto err_context;
6199 } else {
6200 if (group_leader->ctx != ctx)
6201 goto err_context;
6202 }
6203
6204 /*
6205 * Only a group leader can be exclusive or pinned
6206 */
6207 if (attr.exclusive || attr.pinned)
6208 goto err_context;
6209 }
6210
6211 if (output_event) {
6212 err = perf_event_set_output(event, output_event);
6213 if (err)
6214 goto err_context;
6215 }
6216
6217 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event, O_RDWR);
6218 if (IS_ERR(event_file)) {
6219 err = PTR_ERR(event_file);
6220 goto err_context;
6221 }
6222
6223 if (move_group) {
6224 struct perf_event_context *gctx = group_leader->ctx;
6225
6226 mutex_lock(&gctx->mutex);
6227 perf_remove_from_context(group_leader);
6228 list_for_each_entry(sibling, &group_leader->sibling_list,
6229 group_entry) {
6230 perf_remove_from_context(sibling);
6231 put_ctx(gctx);
6232 }
6233 mutex_unlock(&gctx->mutex);
6234 put_ctx(gctx);
6235 }
6236
6237 event->filp = event_file;
6238 WARN_ON_ONCE(ctx->parent_ctx);
6239 mutex_lock(&ctx->mutex);
6240
6241 if (move_group) {
6242 perf_install_in_context(ctx, group_leader, cpu);
6243 get_ctx(ctx);
6244 list_for_each_entry(sibling, &group_leader->sibling_list,
6245 group_entry) {
6246 perf_install_in_context(ctx, sibling, cpu);
6247 get_ctx(ctx);
6248 }
6249 }
6250
6251 perf_install_in_context(ctx, event, cpu);
6252 ++ctx->generation;
6253 perf_unpin_context(ctx);
6254 mutex_unlock(&ctx->mutex);
6255
6256 event->owner = current;
6257
6258 mutex_lock(¤t->perf_event_mutex);
6259 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
6260 mutex_unlock(¤t->perf_event_mutex);
6261
6262 /*
6263 * Precalculate sample_data sizes
6264 */
6265 perf_event__header_size(event);
6266 perf_event__id_header_size(event);
6267
6268 /*
6269 * Drop the reference on the group_event after placing the
6270 * new event on the sibling_list. This ensures destruction
6271 * of the group leader will find the pointer to itself in
6272 * perf_group_detach().
6273 */
6274 fput_light(group_file, fput_needed);
6275 fd_install(event_fd, event_file);
6276 return event_fd;
6277
6278err_context:
6279 perf_unpin_context(ctx);
6280 put_ctx(ctx);
6281err_alloc:
6282 free_event(event);
6283err_task:
6284 if (task)
6285 put_task_struct(task);
6286err_group_fd:
6287 fput_light(group_file, fput_needed);
6288err_fd:
6289 put_unused_fd(event_fd);
6290 return err;
6291}
6292
6293/**
6294 * perf_event_create_kernel_counter
6295 *
6296 * @attr: attributes of the counter to create
6297 * @cpu: cpu in which the counter is bound
6298 * @task: task to profile (NULL for percpu)
6299 */
6300struct perf_event *
6301perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
6302 struct task_struct *task,
6303 perf_overflow_handler_t overflow_handler,
6304 void *context)
6305{
6306 struct perf_event_context *ctx;
6307 struct perf_event *event;
6308 int err;
6309
6310 /*
6311 * Get the target context (task or percpu):
6312 */
6313
6314 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
6315 overflow_handler, context);
6316 if (IS_ERR(event)) {
6317 err = PTR_ERR(event);
6318 goto err;
6319 }
6320
6321 ctx = find_get_context(event->pmu, task, cpu);
6322 if (IS_ERR(ctx)) {
6323 err = PTR_ERR(ctx);
6324 goto err_free;
6325 }
6326
6327 event->filp = NULL;
6328 WARN_ON_ONCE(ctx->parent_ctx);
6329 mutex_lock(&ctx->mutex);
6330 perf_install_in_context(ctx, event, cpu);
6331 ++ctx->generation;
6332 perf_unpin_context(ctx);
6333 mutex_unlock(&ctx->mutex);
6334
6335 return event;
6336
6337err_free:
6338 free_event(event);
6339err:
6340 return ERR_PTR(err);
6341}
6342EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
6343
6344static void sync_child_event(struct perf_event *child_event,
6345 struct task_struct *child)
6346{
6347 struct perf_event *parent_event = child_event->parent;
6348 u64 child_val;
6349
6350 if (child_event->attr.inherit_stat)
6351 perf_event_read_event(child_event, child);
6352
6353 child_val = perf_event_count(child_event);
6354
6355 /*
6356 * Add back the child's count to the parent's count:
6357 */
6358 atomic64_add(child_val, &parent_event->child_count);
6359 atomic64_add(child_event->total_time_enabled,
6360 &parent_event->child_total_time_enabled);
6361 atomic64_add(child_event->total_time_running,
6362 &parent_event->child_total_time_running);
6363
6364 /*
6365 * Remove this event from the parent's list
6366 */
6367 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
6368 mutex_lock(&parent_event->child_mutex);
6369 list_del_init(&child_event->child_list);
6370 mutex_unlock(&parent_event->child_mutex);
6371
6372 /*
6373 * Release the parent event, if this was the last
6374 * reference to it.
6375 */
6376 fput(parent_event->filp);
6377}
6378
6379static void
6380__perf_event_exit_task(struct perf_event *child_event,
6381 struct perf_event_context *child_ctx,
6382 struct task_struct *child)
6383{
6384 if (child_event->parent) {
6385 raw_spin_lock_irq(&child_ctx->lock);
6386 perf_group_detach(child_event);
6387 raw_spin_unlock_irq(&child_ctx->lock);
6388 }
6389
6390 perf_remove_from_context(child_event);
6391
6392 /*
6393 * It can happen that the parent exits first, and has events
6394 * that are still around due to the child reference. These
6395 * events need to be zapped.
6396 */
6397 if (child_event->parent) {
6398 sync_child_event(child_event, child);
6399 free_event(child_event);
6400 }
6401}
6402
6403static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
6404{
6405 struct perf_event *child_event, *tmp;
6406 struct perf_event_context *child_ctx;
6407 unsigned long flags;
6408
6409 if (likely(!child->perf_event_ctxp[ctxn])) {
6410 perf_event_task(child, NULL, 0);
6411 return;
6412 }
6413
6414 local_irq_save(flags);
6415 /*
6416 * We can't reschedule here because interrupts are disabled,
6417 * and either child is current or it is a task that can't be
6418 * scheduled, so we are now safe from rescheduling changing
6419 * our context.
6420 */
6421 child_ctx = rcu_dereference_raw(child->perf_event_ctxp[ctxn]);
6422
6423 /*
6424 * Take the context lock here so that if find_get_context is
6425 * reading child->perf_event_ctxp, we wait until it has
6426 * incremented the context's refcount before we do put_ctx below.
6427 */
6428 raw_spin_lock(&child_ctx->lock);
6429 task_ctx_sched_out(child_ctx);
6430 child->perf_event_ctxp[ctxn] = NULL;
6431 /*
6432 * If this context is a clone; unclone it so it can't get
6433 * swapped to another process while we're removing all
6434 * the events from it.
6435 */
6436 unclone_ctx(child_ctx);
6437 update_context_time(child_ctx);
6438 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
6439
6440 /*
6441 * Report the task dead after unscheduling the events so that we
6442 * won't get any samples after PERF_RECORD_EXIT. We can however still
6443 * get a few PERF_RECORD_READ events.
6444 */
6445 perf_event_task(child, child_ctx, 0);
6446
6447 /*
6448 * We can recurse on the same lock type through:
6449 *
6450 * __perf_event_exit_task()
6451 * sync_child_event()
6452 * fput(parent_event->filp)
6453 * perf_release()
6454 * mutex_lock(&ctx->mutex)
6455 *
6456 * But since its the parent context it won't be the same instance.
6457 */
6458 mutex_lock(&child_ctx->mutex);
6459
6460again:
6461 list_for_each_entry_safe(child_event, tmp, &child_ctx->pinned_groups,
6462 group_entry)
6463 __perf_event_exit_task(child_event, child_ctx, child);
6464
6465 list_for_each_entry_safe(child_event, tmp, &child_ctx->flexible_groups,
6466 group_entry)
6467 __perf_event_exit_task(child_event, child_ctx, child);
6468
6469 /*
6470 * If the last event was a group event, it will have appended all
6471 * its siblings to the list, but we obtained 'tmp' before that which
6472 * will still point to the list head terminating the iteration.
6473 */
6474 if (!list_empty(&child_ctx->pinned_groups) ||
6475 !list_empty(&child_ctx->flexible_groups))
6476 goto again;
6477
6478 mutex_unlock(&child_ctx->mutex);
6479
6480 put_ctx(child_ctx);
6481}
6482
6483/*
6484 * When a child task exits, feed back event values to parent events.
6485 */
6486void perf_event_exit_task(struct task_struct *child)
6487{
6488 struct perf_event *event, *tmp;
6489 int ctxn;
6490
6491 mutex_lock(&child->perf_event_mutex);
6492 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
6493 owner_entry) {
6494 list_del_init(&event->owner_entry);
6495
6496 /*
6497 * Ensure the list deletion is visible before we clear
6498 * the owner, closes a race against perf_release() where
6499 * we need to serialize on the owner->perf_event_mutex.
6500 */
6501 smp_wmb();
6502 event->owner = NULL;
6503 }
6504 mutex_unlock(&child->perf_event_mutex);
6505
6506 for_each_task_context_nr(ctxn)
6507 perf_event_exit_task_context(child, ctxn);
6508}
6509
6510static void perf_free_event(struct perf_event *event,
6511 struct perf_event_context *ctx)
6512{
6513 struct perf_event *parent = event->parent;
6514
6515 if (WARN_ON_ONCE(!parent))
6516 return;
6517
6518 mutex_lock(&parent->child_mutex);
6519 list_del_init(&event->child_list);
6520 mutex_unlock(&parent->child_mutex);
6521
6522 fput(parent->filp);
6523
6524 perf_group_detach(event);
6525 list_del_event(event, ctx);
6526 free_event(event);
6527}
6528
6529/*
6530 * free an unexposed, unused context as created by inheritance by
6531 * perf_event_init_task below, used by fork() in case of fail.
6532 */
6533void perf_event_free_task(struct task_struct *task)
6534{
6535 struct perf_event_context *ctx;
6536 struct perf_event *event, *tmp;
6537 int ctxn;
6538
6539 for_each_task_context_nr(ctxn) {
6540 ctx = task->perf_event_ctxp[ctxn];
6541 if (!ctx)
6542 continue;
6543
6544 mutex_lock(&ctx->mutex);
6545again:
6546 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
6547 group_entry)
6548 perf_free_event(event, ctx);
6549
6550 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
6551 group_entry)
6552 perf_free_event(event, ctx);
6553
6554 if (!list_empty(&ctx->pinned_groups) ||
6555 !list_empty(&ctx->flexible_groups))
6556 goto again;
6557
6558 mutex_unlock(&ctx->mutex);
6559
6560 put_ctx(ctx);
6561 }
6562}
6563
6564void perf_event_delayed_put(struct task_struct *task)
6565{
6566 int ctxn;
6567
6568 for_each_task_context_nr(ctxn)
6569 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
6570}
6571
6572/*
6573 * inherit a event from parent task to child task:
6574 */
6575static struct perf_event *
6576inherit_event(struct perf_event *parent_event,
6577 struct task_struct *parent,
6578 struct perf_event_context *parent_ctx,
6579 struct task_struct *child,
6580 struct perf_event *group_leader,
6581 struct perf_event_context *child_ctx)
6582{
6583 struct perf_event *child_event;
6584 unsigned long flags;
6585
6586 /*
6587 * Instead of creating recursive hierarchies of events,
6588 * we link inherited events back to the original parent,
6589 * which has a filp for sure, which we use as the reference
6590 * count:
6591 */
6592 if (parent_event->parent)
6593 parent_event = parent_event->parent;
6594
6595 child_event = perf_event_alloc(&parent_event->attr,
6596 parent_event->cpu,
6597 child,
6598 group_leader, parent_event,
6599 NULL, NULL);
6600 if (IS_ERR(child_event))
6601 return child_event;
6602 get_ctx(child_ctx);
6603
6604 /*
6605 * Make the child state follow the state of the parent event,
6606 * not its attr.disabled bit. We hold the parent's mutex,
6607 * so we won't race with perf_event_{en, dis}able_family.
6608 */
6609 if (parent_event->state >= PERF_EVENT_STATE_INACTIVE)
6610 child_event->state = PERF_EVENT_STATE_INACTIVE;
6611 else
6612 child_event->state = PERF_EVENT_STATE_OFF;
6613
6614 if (parent_event->attr.freq) {
6615 u64 sample_period = parent_event->hw.sample_period;
6616 struct hw_perf_event *hwc = &child_event->hw;
6617
6618 hwc->sample_period = sample_period;
6619 hwc->last_period = sample_period;
6620
6621 local64_set(&hwc->period_left, sample_period);
6622 }
6623
6624 child_event->ctx = child_ctx;
6625 child_event->overflow_handler = parent_event->overflow_handler;
6626 child_event->overflow_handler_context
6627 = parent_event->overflow_handler_context;
6628
6629 /*
6630 * Precalculate sample_data sizes
6631 */
6632 perf_event__header_size(child_event);
6633 perf_event__id_header_size(child_event);
6634
6635 /*
6636 * Link it up in the child's context:
6637 */
6638 raw_spin_lock_irqsave(&child_ctx->lock, flags);
6639 add_event_to_ctx(child_event, child_ctx);
6640 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
6641
6642 /*
6643 * Get a reference to the parent filp - we will fput it
6644 * when the child event exits. This is safe to do because
6645 * we are in the parent and we know that the filp still
6646 * exists and has a nonzero count:
6647 */
6648 atomic_long_inc(&parent_event->filp->f_count);
6649
6650 /*
6651 * Link this into the parent event's child list
6652 */
6653 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
6654 mutex_lock(&parent_event->child_mutex);
6655 list_add_tail(&child_event->child_list, &parent_event->child_list);
6656 mutex_unlock(&parent_event->child_mutex);
6657
6658 return child_event;
6659}
6660
6661static int inherit_group(struct perf_event *parent_event,
6662 struct task_struct *parent,
6663 struct perf_event_context *parent_ctx,
6664 struct task_struct *child,
6665 struct perf_event_context *child_ctx)
6666{
6667 struct perf_event *leader;
6668 struct perf_event *sub;
6669 struct perf_event *child_ctr;
6670
6671 leader = inherit_event(parent_event, parent, parent_ctx,
6672 child, NULL, child_ctx);
6673 if (IS_ERR(leader))
6674 return PTR_ERR(leader);
6675 list_for_each_entry(sub, &parent_event->sibling_list, group_entry) {
6676 child_ctr = inherit_event(sub, parent, parent_ctx,
6677 child, leader, child_ctx);
6678 if (IS_ERR(child_ctr))
6679 return PTR_ERR(child_ctr);
6680 }
6681 return 0;
6682}
6683
6684static int
6685inherit_task_group(struct perf_event *event, struct task_struct *parent,
6686 struct perf_event_context *parent_ctx,
6687 struct task_struct *child, int ctxn,
6688 int *inherited_all)
6689{
6690 int ret;
6691 struct perf_event_context *child_ctx;
6692
6693 if (!event->attr.inherit) {
6694 *inherited_all = 0;
6695 return 0;
6696 }
6697
6698 child_ctx = child->perf_event_ctxp[ctxn];
6699 if (!child_ctx) {
6700 /*
6701 * This is executed from the parent task context, so
6702 * inherit events that have been marked for cloning.
6703 * First allocate and initialize a context for the
6704 * child.
6705 */
6706
6707 child_ctx = alloc_perf_context(event->pmu, child);
6708 if (!child_ctx)
6709 return -ENOMEM;
6710
6711 child->perf_event_ctxp[ctxn] = child_ctx;
6712 }
6713
6714 ret = inherit_group(event, parent, parent_ctx,
6715 child, child_ctx);
6716
6717 if (ret)
6718 *inherited_all = 0;
6719
6720 return ret;
6721}
6722
6723/*
6724 * Initialize the perf_event context in task_struct
6725 */
6726int perf_event_init_context(struct task_struct *child, int ctxn)
6727{
6728 struct perf_event_context *child_ctx, *parent_ctx;
6729 struct perf_event_context *cloned_ctx;
6730 struct perf_event *event;
6731 struct task_struct *parent = current;
6732 int inherited_all = 1;
6733 unsigned long flags;
6734 int ret = 0;
6735
6736 if (likely(!parent->perf_event_ctxp[ctxn]))
6737 return 0;
6738
6739 /*
6740 * If the parent's context is a clone, pin it so it won't get
6741 * swapped under us.
6742 */
6743 parent_ctx = perf_pin_task_context(parent, ctxn);
6744
6745 /*
6746 * No need to check if parent_ctx != NULL here; since we saw
6747 * it non-NULL earlier, the only reason for it to become NULL
6748 * is if we exit, and since we're currently in the middle of
6749 * a fork we can't be exiting at the same time.
6750 */
6751
6752 /*
6753 * Lock the parent list. No need to lock the child - not PID
6754 * hashed yet and not running, so nobody can access it.
6755 */
6756 mutex_lock(&parent_ctx->mutex);
6757
6758 /*
6759 * We dont have to disable NMIs - we are only looking at
6760 * the list, not manipulating it:
6761 */
6762 list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
6763 ret = inherit_task_group(event, parent, parent_ctx,
6764 child, ctxn, &inherited_all);
6765 if (ret)
6766 break;
6767 }
6768
6769 /*
6770 * We can't hold ctx->lock when iterating the ->flexible_group list due
6771 * to allocations, but we need to prevent rotation because
6772 * rotate_ctx() will change the list from interrupt context.
6773 */
6774 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
6775 parent_ctx->rotate_disable = 1;
6776 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
6777
6778 list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
6779 ret = inherit_task_group(event, parent, parent_ctx,
6780 child, ctxn, &inherited_all);
6781 if (ret)
6782 break;
6783 }
6784
6785 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
6786 parent_ctx->rotate_disable = 0;
6787
6788 child_ctx = child->perf_event_ctxp[ctxn];
6789
6790 if (child_ctx && inherited_all) {
6791 /*
6792 * Mark the child context as a clone of the parent
6793 * context, or of whatever the parent is a clone of.
6794 *
6795 * Note that if the parent is a clone, the holding of
6796 * parent_ctx->lock avoids it from being uncloned.
6797 */
6798 cloned_ctx = parent_ctx->parent_ctx;
6799 if (cloned_ctx) {
6800 child_ctx->parent_ctx = cloned_ctx;
6801 child_ctx->parent_gen = parent_ctx->parent_gen;
6802 } else {
6803 child_ctx->parent_ctx = parent_ctx;
6804 child_ctx->parent_gen = parent_ctx->generation;
6805 }
6806 get_ctx(child_ctx->parent_ctx);
6807 }
6808
6809 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
6810 mutex_unlock(&parent_ctx->mutex);
6811
6812 perf_unpin_context(parent_ctx);
6813 put_ctx(parent_ctx);
6814
6815 return ret;
6816}
6817
6818/*
6819 * Initialize the perf_event context in task_struct
6820 */
6821int perf_event_init_task(struct task_struct *child)
6822{
6823 int ctxn, ret;
6824
6825 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
6826 mutex_init(&child->perf_event_mutex);
6827 INIT_LIST_HEAD(&child->perf_event_list);
6828
6829 for_each_task_context_nr(ctxn) {
6830 ret = perf_event_init_context(child, ctxn);
6831 if (ret)
6832 return ret;
6833 }
6834
6835 return 0;
6836}
6837
6838static void __init perf_event_init_all_cpus(void)
6839{
6840 struct swevent_htable *swhash;
6841 int cpu;
6842
6843 for_each_possible_cpu(cpu) {
6844 swhash = &per_cpu(swevent_htable, cpu);
6845 mutex_init(&swhash->hlist_mutex);
6846 INIT_LIST_HEAD(&per_cpu(rotation_list, cpu));
6847 }
6848}
6849
6850static void __cpuinit perf_event_init_cpu(int cpu)
6851{
6852 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6853
6854 mutex_lock(&swhash->hlist_mutex);
6855 if (swhash->hlist_refcount > 0) {
6856 struct swevent_hlist *hlist;
6857
6858 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
6859 WARN_ON(!hlist);
6860 rcu_assign_pointer(swhash->swevent_hlist, hlist);
6861 }
6862 mutex_unlock(&swhash->hlist_mutex);
6863}
6864
6865#if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC
6866static void perf_pmu_rotate_stop(struct pmu *pmu)
6867{
6868 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6869
6870 WARN_ON(!irqs_disabled());
6871
6872 list_del_init(&cpuctx->rotation_list);
6873}
6874
6875static void __perf_event_exit_context(void *__info)
6876{
6877 struct perf_event_context *ctx = __info;
6878 struct perf_event *event, *tmp;
6879
6880 perf_pmu_rotate_stop(ctx->pmu);
6881
6882 list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
6883 __perf_remove_from_context(event);
6884 list_for_each_entry_safe(event, tmp, &ctx->flexible_groups, group_entry)
6885 __perf_remove_from_context(event);
6886}
6887
6888static void perf_event_exit_cpu_context(int cpu)
6889{
6890 struct perf_event_context *ctx;
6891 struct pmu *pmu;
6892 int idx;
6893
6894 idx = srcu_read_lock(&pmus_srcu);
6895 list_for_each_entry_rcu(pmu, &pmus, entry) {
6896 ctx = &per_cpu_ptr(pmu->pmu_cpu_context, cpu)->ctx;
6897
6898 mutex_lock(&ctx->mutex);
6899 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
6900 mutex_unlock(&ctx->mutex);
6901 }
6902 srcu_read_unlock(&pmus_srcu, idx);
6903}
6904
6905static void perf_event_exit_cpu(int cpu)
6906{
6907 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
6908
6909 mutex_lock(&swhash->hlist_mutex);
6910 swevent_hlist_release(swhash);
6911 mutex_unlock(&swhash->hlist_mutex);
6912
6913 perf_event_exit_cpu_context(cpu);
6914}
6915#else
6916static inline void perf_event_exit_cpu(int cpu) { }
6917#endif
6918
6919static int
6920perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
6921{
6922 int cpu;
6923
6924 for_each_online_cpu(cpu)
6925 perf_event_exit_cpu(cpu);
6926
6927 return NOTIFY_OK;
6928}
6929
6930/*
6931 * Run the perf reboot notifier at the very last possible moment so that
6932 * the generic watchdog code runs as long as possible.
6933 */
6934static struct notifier_block perf_reboot_notifier = {
6935 .notifier_call = perf_reboot,
6936 .priority = INT_MIN,
6937};
6938
6939static int __cpuinit
6940perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
6941{
6942 unsigned int cpu = (long)hcpu;
6943
6944 switch (action & ~CPU_TASKS_FROZEN) {
6945
6946 case CPU_UP_PREPARE:
6947 case CPU_DOWN_FAILED:
6948 perf_event_init_cpu(cpu);
6949 break;
6950
6951 case CPU_UP_CANCELED:
6952 case CPU_DOWN_PREPARE:
6953 perf_event_exit_cpu(cpu);
6954 break;
6955
6956 default:
6957 break;
6958 }
6959
6960 return NOTIFY_OK;
6961}
6962
6963void __init perf_event_init(void)
6964{
6965 int ret;
6966
6967 idr_init(&pmu_idr);
6968
6969 perf_event_init_all_cpus();
6970 init_srcu_struct(&pmus_srcu);
6971 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
6972 perf_pmu_register(&perf_cpu_clock, NULL, -1);
6973 perf_pmu_register(&perf_task_clock, NULL, -1);
6974 perf_tp_register();
6975 perf_cpu_notifier(perf_cpu_notify);
6976 register_reboot_notifier(&perf_reboot_notifier);
6977
6978 ret = init_hw_breakpoint();
6979 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
6980}
6981
6982static int __init perf_event_sysfs_init(void)
6983{
6984 struct pmu *pmu;
6985 int ret;
6986
6987 mutex_lock(&pmus_lock);
6988
6989 ret = bus_register(&pmu_bus);
6990 if (ret)
6991 goto unlock;
6992
6993 list_for_each_entry(pmu, &pmus, entry) {
6994 if (!pmu->name || pmu->type < 0)
6995 continue;
6996
6997 ret = pmu_dev_alloc(pmu);
6998 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
6999 }
7000 pmu_bus_running = 1;
7001 ret = 0;
7002
7003unlock:
7004 mutex_unlock(&pmus_lock);
7005
7006 return ret;
7007}
7008device_initcall(perf_event_sysfs_init);
7009
7010#ifdef CONFIG_CGROUP_PERF
7011static struct cgroup_subsys_state *perf_cgroup_create(
7012 struct cgroup_subsys *ss, struct cgroup *cont)
7013{
7014 struct perf_cgroup *jc;
7015
7016 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
7017 if (!jc)
7018 return ERR_PTR(-ENOMEM);
7019
7020 jc->info = alloc_percpu(struct perf_cgroup_info);
7021 if (!jc->info) {
7022 kfree(jc);
7023 return ERR_PTR(-ENOMEM);
7024 }
7025
7026 return &jc->css;
7027}
7028
7029static void perf_cgroup_destroy(struct cgroup_subsys *ss,
7030 struct cgroup *cont)
7031{
7032 struct perf_cgroup *jc;
7033 jc = container_of(cgroup_subsys_state(cont, perf_subsys_id),
7034 struct perf_cgroup, css);
7035 free_percpu(jc->info);
7036 kfree(jc);
7037}
7038
7039static int __perf_cgroup_move(void *info)
7040{
7041 struct task_struct *task = info;
7042 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
7043 return 0;
7044}
7045
7046static void
7047perf_cgroup_attach_task(struct cgroup *cgrp, struct task_struct *task)
7048{
7049 task_function_call(task, __perf_cgroup_move, task);
7050}
7051
7052static void perf_cgroup_exit(struct cgroup_subsys *ss, struct cgroup *cgrp,
7053 struct cgroup *old_cgrp, struct task_struct *task)
7054{
7055 /*
7056 * cgroup_exit() is called in the copy_process() failure path.
7057 * Ignore this case since the task hasn't ran yet, this avoids
7058 * trying to poke a half freed task state from generic code.
7059 */
7060 if (!(task->flags & PF_EXITING))
7061 return;
7062
7063 perf_cgroup_attach_task(cgrp, task);
7064}
7065
7066struct cgroup_subsys perf_subsys = {
7067 .name = "perf_event",
7068 .subsys_id = perf_subsys_id,
7069 .create = perf_cgroup_create,
7070 .destroy = perf_cgroup_destroy,
7071 .exit = perf_cgroup_exit,
7072 .attach_task = perf_cgroup_attach_task,
7073};
7074#endif /* CONFIG_CGROUP_PERF */