1 // SPDX-License-Identifier: GPL-2.0
3 * Performance events core code:
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>
13 #include <linux/cpu.h>
14 #include <linux/smp.h>
15 #include <linux/idr.h>
16 #include <linux/file.h>
17 #include <linux/poll.h>
18 #include <linux/slab.h>
19 #include <linux/hash.h>
20 #include <linux/tick.h>
21 #include <linux/sysfs.h>
22 #include <linux/dcache.h>
23 #include <linux/percpu.h>
24 #include <linux/ptrace.h>
25 #include <linux/reboot.h>
26 #include <linux/vmstat.h>
27 #include <linux/device.h>
28 #include <linux/export.h>
29 #include <linux/vmalloc.h>
30 #include <linux/hardirq.h>
31 #include <linux/hugetlb.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/trace_events.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
47 #include <linux/namei.h>
48 #include <linux/parser.h>
49 #include <linux/sched/clock.h>
50 #include <linux/sched/mm.h>
51 #include <linux/proc_ns.h>
52 #include <linux/mount.h>
53 #include <linux/min_heap.h>
57 #include <asm/irq_regs.h>
59 typedef int (*remote_function_f)(void *);
61 struct remote_function_call {
62 struct task_struct *p;
63 remote_function_f func;
68 static void remote_function(void *data)
70 struct remote_function_call *tfc = data;
71 struct task_struct *p = tfc->p;
75 if (task_cpu(p) != smp_processor_id())
79 * Now that we're on right CPU with IRQs disabled, we can test
80 * if we hit the right task without races.
83 tfc->ret = -ESRCH; /* No such (running) process */
88 tfc->ret = tfc->func(tfc->info);
92 * task_function_call - call a function on the cpu on which a task runs
93 * @p: the task to evaluate
94 * @func: the function to be called
95 * @info: the function call argument
97 * Calls the function @func when the task is currently running. This might
98 * be on the current CPU, which just calls the function directly
100 * returns: @func return value, or
101 * -ESRCH - when the process isn't running
102 * -EAGAIN - when the process moved away
105 task_function_call(struct task_struct *p, remote_function_f func, void *info)
107 struct remote_function_call data = {
116 ret = smp_call_function_single(task_cpu(p), remote_function, &data, 1);
119 } while (ret == -EAGAIN);
125 * cpu_function_call - call a function on the cpu
126 * @func: the function to be called
127 * @info: the function call argument
129 * Calls the function @func on the remote cpu.
131 * returns: @func return value or -ENXIO when the cpu is offline
133 static int cpu_function_call(int cpu, remote_function_f func, void *info)
135 struct remote_function_call data = {
139 .ret = -ENXIO, /* No such CPU */
142 smp_call_function_single(cpu, remote_function, &data, 1);
147 static inline struct perf_cpu_context *
148 __get_cpu_context(struct perf_event_context *ctx)
150 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
153 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
154 struct perf_event_context *ctx)
156 raw_spin_lock(&cpuctx->ctx.lock);
158 raw_spin_lock(&ctx->lock);
161 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
162 struct perf_event_context *ctx)
165 raw_spin_unlock(&ctx->lock);
166 raw_spin_unlock(&cpuctx->ctx.lock);
169 #define TASK_TOMBSTONE ((void *)-1L)
171 static bool is_kernel_event(struct perf_event *event)
173 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
177 * On task ctx scheduling...
179 * When !ctx->nr_events a task context will not be scheduled. This means
180 * we can disable the scheduler hooks (for performance) without leaving
181 * pending task ctx state.
183 * This however results in two special cases:
185 * - removing the last event from a task ctx; this is relatively straight
186 * forward and is done in __perf_remove_from_context.
188 * - adding the first event to a task ctx; this is tricky because we cannot
189 * rely on ctx->is_active and therefore cannot use event_function_call().
190 * See perf_install_in_context().
192 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
195 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
196 struct perf_event_context *, void *);
198 struct event_function_struct {
199 struct perf_event *event;
204 static int event_function(void *info)
206 struct event_function_struct *efs = info;
207 struct perf_event *event = efs->event;
208 struct perf_event_context *ctx = event->ctx;
209 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
210 struct perf_event_context *task_ctx = cpuctx->task_ctx;
213 lockdep_assert_irqs_disabled();
215 perf_ctx_lock(cpuctx, task_ctx);
217 * Since we do the IPI call without holding ctx->lock things can have
218 * changed, double check we hit the task we set out to hit.
221 if (ctx->task != current) {
227 * We only use event_function_call() on established contexts,
228 * and event_function() is only ever called when active (or
229 * rather, we'll have bailed in task_function_call() or the
230 * above ctx->task != current test), therefore we must have
231 * ctx->is_active here.
233 WARN_ON_ONCE(!ctx->is_active);
235 * And since we have ctx->is_active, cpuctx->task_ctx must
238 WARN_ON_ONCE(task_ctx != ctx);
240 WARN_ON_ONCE(&cpuctx->ctx != ctx);
243 efs->func(event, cpuctx, ctx, efs->data);
245 perf_ctx_unlock(cpuctx, task_ctx);
250 static void event_function_call(struct perf_event *event, event_f func, void *data)
252 struct perf_event_context *ctx = event->ctx;
253 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
254 struct event_function_struct efs = {
260 if (!event->parent) {
262 * If this is a !child event, we must hold ctx::mutex to
263 * stabilize the the event->ctx relation. See
264 * perf_event_ctx_lock().
266 lockdep_assert_held(&ctx->mutex);
270 cpu_function_call(event->cpu, event_function, &efs);
274 if (task == TASK_TOMBSTONE)
278 if (!task_function_call(task, event_function, &efs))
281 raw_spin_lock_irq(&ctx->lock);
283 * Reload the task pointer, it might have been changed by
284 * a concurrent perf_event_context_sched_out().
287 if (task == TASK_TOMBSTONE) {
288 raw_spin_unlock_irq(&ctx->lock);
291 if (ctx->is_active) {
292 raw_spin_unlock_irq(&ctx->lock);
295 func(event, NULL, ctx, data);
296 raw_spin_unlock_irq(&ctx->lock);
300 * Similar to event_function_call() + event_function(), but hard assumes IRQs
301 * are already disabled and we're on the right CPU.
303 static void event_function_local(struct perf_event *event, event_f func, void *data)
305 struct perf_event_context *ctx = event->ctx;
306 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
307 struct task_struct *task = READ_ONCE(ctx->task);
308 struct perf_event_context *task_ctx = NULL;
310 lockdep_assert_irqs_disabled();
313 if (task == TASK_TOMBSTONE)
319 perf_ctx_lock(cpuctx, task_ctx);
322 if (task == TASK_TOMBSTONE)
327 * We must be either inactive or active and the right task,
328 * otherwise we're screwed, since we cannot IPI to somewhere
331 if (ctx->is_active) {
332 if (WARN_ON_ONCE(task != current))
335 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
339 WARN_ON_ONCE(&cpuctx->ctx != ctx);
342 func(event, cpuctx, ctx, data);
344 perf_ctx_unlock(cpuctx, task_ctx);
347 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
348 PERF_FLAG_FD_OUTPUT |\
349 PERF_FLAG_PID_CGROUP |\
350 PERF_FLAG_FD_CLOEXEC)
353 * branch priv levels that need permission checks
355 #define PERF_SAMPLE_BRANCH_PERM_PLM \
356 (PERF_SAMPLE_BRANCH_KERNEL |\
357 PERF_SAMPLE_BRANCH_HV)
360 EVENT_FLEXIBLE = 0x1,
363 /* see ctx_resched() for details */
365 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
369 * perf_sched_events : >0 events exist
370 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
373 static void perf_sched_delayed(struct work_struct *work);
374 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
375 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
376 static DEFINE_MUTEX(perf_sched_mutex);
377 static atomic_t perf_sched_count;
379 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
380 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
381 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
383 static atomic_t nr_mmap_events __read_mostly;
384 static atomic_t nr_comm_events __read_mostly;
385 static atomic_t nr_namespaces_events __read_mostly;
386 static atomic_t nr_task_events __read_mostly;
387 static atomic_t nr_freq_events __read_mostly;
388 static atomic_t nr_switch_events __read_mostly;
389 static atomic_t nr_ksymbol_events __read_mostly;
390 static atomic_t nr_bpf_events __read_mostly;
391 static atomic_t nr_cgroup_events __read_mostly;
393 static LIST_HEAD(pmus);
394 static DEFINE_MUTEX(pmus_lock);
395 static struct srcu_struct pmus_srcu;
396 static cpumask_var_t perf_online_mask;
399 * perf event paranoia level:
400 * -1 - not paranoid at all
401 * 0 - disallow raw tracepoint access for unpriv
402 * 1 - disallow cpu events for unpriv
403 * 2 - disallow kernel profiling for unpriv
405 int sysctl_perf_event_paranoid __read_mostly = 2;
407 /* Minimum for 512 kiB + 1 user control page */
408 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
411 * max perf event sample rate
413 #define DEFAULT_MAX_SAMPLE_RATE 100000
414 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
415 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
417 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
419 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
420 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
422 static int perf_sample_allowed_ns __read_mostly =
423 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
425 static void update_perf_cpu_limits(void)
427 u64 tmp = perf_sample_period_ns;
429 tmp *= sysctl_perf_cpu_time_max_percent;
430 tmp = div_u64(tmp, 100);
434 WRITE_ONCE(perf_sample_allowed_ns, tmp);
437 static bool perf_rotate_context(struct perf_cpu_context *cpuctx);
439 int perf_proc_update_handler(struct ctl_table *table, int write,
440 void __user *buffer, size_t *lenp,
444 int perf_cpu = sysctl_perf_cpu_time_max_percent;
446 * If throttling is disabled don't allow the write:
448 if (write && (perf_cpu == 100 || perf_cpu == 0))
451 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
455 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
456 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
457 update_perf_cpu_limits();
462 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
464 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
465 void __user *buffer, size_t *lenp,
468 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
473 if (sysctl_perf_cpu_time_max_percent == 100 ||
474 sysctl_perf_cpu_time_max_percent == 0) {
476 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
477 WRITE_ONCE(perf_sample_allowed_ns, 0);
479 update_perf_cpu_limits();
486 * perf samples are done in some very critical code paths (NMIs).
487 * If they take too much CPU time, the system can lock up and not
488 * get any real work done. This will drop the sample rate when
489 * we detect that events are taking too long.
491 #define NR_ACCUMULATED_SAMPLES 128
492 static DEFINE_PER_CPU(u64, running_sample_length);
494 static u64 __report_avg;
495 static u64 __report_allowed;
497 static void perf_duration_warn(struct irq_work *w)
499 printk_ratelimited(KERN_INFO
500 "perf: interrupt took too long (%lld > %lld), lowering "
501 "kernel.perf_event_max_sample_rate to %d\n",
502 __report_avg, __report_allowed,
503 sysctl_perf_event_sample_rate);
506 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
508 void perf_sample_event_took(u64 sample_len_ns)
510 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
518 /* Decay the counter by 1 average sample. */
519 running_len = __this_cpu_read(running_sample_length);
520 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
521 running_len += sample_len_ns;
522 __this_cpu_write(running_sample_length, running_len);
525 * Note: this will be biased artifically low until we have
526 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
527 * from having to maintain a count.
529 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
530 if (avg_len <= max_len)
533 __report_avg = avg_len;
534 __report_allowed = max_len;
537 * Compute a throttle threshold 25% below the current duration.
539 avg_len += avg_len / 4;
540 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
546 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
547 WRITE_ONCE(max_samples_per_tick, max);
549 sysctl_perf_event_sample_rate = max * HZ;
550 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
552 if (!irq_work_queue(&perf_duration_work)) {
553 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
554 "kernel.perf_event_max_sample_rate to %d\n",
555 __report_avg, __report_allowed,
556 sysctl_perf_event_sample_rate);
560 static atomic64_t perf_event_id;
562 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
563 enum event_type_t event_type);
565 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
566 enum event_type_t event_type,
567 struct task_struct *task);
569 static void update_context_time(struct perf_event_context *ctx);
570 static u64 perf_event_time(struct perf_event *event);
572 void __weak perf_event_print_debug(void) { }
574 extern __weak const char *perf_pmu_name(void)
579 static inline u64 perf_clock(void)
581 return local_clock();
584 static inline u64 perf_event_clock(struct perf_event *event)
586 return event->clock();
590 * State based event timekeeping...
592 * The basic idea is to use event->state to determine which (if any) time
593 * fields to increment with the current delta. This means we only need to
594 * update timestamps when we change state or when they are explicitly requested
597 * Event groups make things a little more complicated, but not terribly so. The
598 * rules for a group are that if the group leader is OFF the entire group is
599 * OFF, irrespecive of what the group member states are. This results in
600 * __perf_effective_state().
602 * A futher ramification is that when a group leader flips between OFF and
603 * !OFF, we need to update all group member times.
606 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
607 * need to make sure the relevant context time is updated before we try and
608 * update our timestamps.
611 static __always_inline enum perf_event_state
612 __perf_effective_state(struct perf_event *event)
614 struct perf_event *leader = event->group_leader;
616 if (leader->state <= PERF_EVENT_STATE_OFF)
617 return leader->state;
622 static __always_inline void
623 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
625 enum perf_event_state state = __perf_effective_state(event);
626 u64 delta = now - event->tstamp;
628 *enabled = event->total_time_enabled;
629 if (state >= PERF_EVENT_STATE_INACTIVE)
632 *running = event->total_time_running;
633 if (state >= PERF_EVENT_STATE_ACTIVE)
637 static void perf_event_update_time(struct perf_event *event)
639 u64 now = perf_event_time(event);
641 __perf_update_times(event, now, &event->total_time_enabled,
642 &event->total_time_running);
646 static void perf_event_update_sibling_time(struct perf_event *leader)
648 struct perf_event *sibling;
650 for_each_sibling_event(sibling, leader)
651 perf_event_update_time(sibling);
655 perf_event_set_state(struct perf_event *event, enum perf_event_state state)
657 if (event->state == state)
660 perf_event_update_time(event);
662 * If a group leader gets enabled/disabled all its siblings
665 if ((event->state < 0) ^ (state < 0))
666 perf_event_update_sibling_time(event);
668 WRITE_ONCE(event->state, state);
671 #ifdef CONFIG_CGROUP_PERF
674 perf_cgroup_match(struct perf_event *event)
676 struct perf_event_context *ctx = event->ctx;
677 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
679 /* @event doesn't care about cgroup */
683 /* wants specific cgroup scope but @cpuctx isn't associated with any */
688 * Cgroup scoping is recursive. An event enabled for a cgroup is
689 * also enabled for all its descendant cgroups. If @cpuctx's
690 * cgroup is a descendant of @event's (the test covers identity
691 * case), it's a match.
693 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
694 event->cgrp->css.cgroup);
697 static inline void perf_detach_cgroup(struct perf_event *event)
699 css_put(&event->cgrp->css);
703 static inline int is_cgroup_event(struct perf_event *event)
705 return event->cgrp != NULL;
708 static inline u64 perf_cgroup_event_time(struct perf_event *event)
710 struct perf_cgroup_info *t;
712 t = per_cpu_ptr(event->cgrp->info, event->cpu);
716 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
718 struct perf_cgroup_info *info;
723 info = this_cpu_ptr(cgrp->info);
725 info->time += now - info->timestamp;
726 info->timestamp = now;
729 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
731 struct perf_cgroup *cgrp = cpuctx->cgrp;
732 struct cgroup_subsys_state *css;
735 for (css = &cgrp->css; css; css = css->parent) {
736 cgrp = container_of(css, struct perf_cgroup, css);
737 __update_cgrp_time(cgrp);
742 static inline void update_cgrp_time_from_event(struct perf_event *event)
744 struct perf_cgroup *cgrp;
747 * ensure we access cgroup data only when needed and
748 * when we know the cgroup is pinned (css_get)
750 if (!is_cgroup_event(event))
753 cgrp = perf_cgroup_from_task(current, event->ctx);
755 * Do not update time when cgroup is not active
757 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
758 __update_cgrp_time(event->cgrp);
762 perf_cgroup_set_timestamp(struct task_struct *task,
763 struct perf_event_context *ctx)
765 struct perf_cgroup *cgrp;
766 struct perf_cgroup_info *info;
767 struct cgroup_subsys_state *css;
770 * ctx->lock held by caller
771 * ensure we do not access cgroup data
772 * unless we have the cgroup pinned (css_get)
774 if (!task || !ctx->nr_cgroups)
777 cgrp = perf_cgroup_from_task(task, ctx);
779 for (css = &cgrp->css; css; css = css->parent) {
780 cgrp = container_of(css, struct perf_cgroup, css);
781 info = this_cpu_ptr(cgrp->info);
782 info->timestamp = ctx->timestamp;
786 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
788 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
789 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
792 * reschedule events based on the cgroup constraint of task.
794 * mode SWOUT : schedule out everything
795 * mode SWIN : schedule in based on cgroup for next
797 static void perf_cgroup_switch(struct task_struct *task, int mode)
799 struct perf_cpu_context *cpuctx;
800 struct list_head *list;
804 * Disable interrupts and preemption to avoid this CPU's
805 * cgrp_cpuctx_entry to change under us.
807 local_irq_save(flags);
809 list = this_cpu_ptr(&cgrp_cpuctx_list);
810 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
811 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
813 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
814 perf_pmu_disable(cpuctx->ctx.pmu);
816 if (mode & PERF_CGROUP_SWOUT) {
817 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
819 * must not be done before ctxswout due
820 * to event_filter_match() in event_sched_out()
825 if (mode & PERF_CGROUP_SWIN) {
826 WARN_ON_ONCE(cpuctx->cgrp);
828 * set cgrp before ctxsw in to allow
829 * event_filter_match() to not have to pass
831 * we pass the cpuctx->ctx to perf_cgroup_from_task()
832 * because cgorup events are only per-cpu
834 cpuctx->cgrp = perf_cgroup_from_task(task,
836 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
838 perf_pmu_enable(cpuctx->ctx.pmu);
839 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
842 local_irq_restore(flags);
845 static inline void perf_cgroup_sched_out(struct task_struct *task,
846 struct task_struct *next)
848 struct perf_cgroup *cgrp1;
849 struct perf_cgroup *cgrp2 = NULL;
853 * we come here when we know perf_cgroup_events > 0
854 * we do not need to pass the ctx here because we know
855 * we are holding the rcu lock
857 cgrp1 = perf_cgroup_from_task(task, NULL);
858 cgrp2 = perf_cgroup_from_task(next, NULL);
861 * only schedule out current cgroup events if we know
862 * that we are switching to a different cgroup. Otherwise,
863 * do no touch the cgroup events.
866 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
871 static inline void perf_cgroup_sched_in(struct task_struct *prev,
872 struct task_struct *task)
874 struct perf_cgroup *cgrp1;
875 struct perf_cgroup *cgrp2 = NULL;
879 * we come here when we know perf_cgroup_events > 0
880 * we do not need to pass the ctx here because we know
881 * we are holding the rcu lock
883 cgrp1 = perf_cgroup_from_task(task, NULL);
884 cgrp2 = perf_cgroup_from_task(prev, NULL);
887 * only need to schedule in cgroup events if we are changing
888 * cgroup during ctxsw. Cgroup events were not scheduled
889 * out of ctxsw out if that was not the case.
892 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
897 static int perf_cgroup_ensure_storage(struct perf_event *event,
898 struct cgroup_subsys_state *css)
900 struct perf_cpu_context *cpuctx;
901 struct perf_event **storage;
902 int cpu, heap_size, ret = 0;
905 * Allow storage to have sufficent space for an iterator for each
906 * possibly nested cgroup plus an iterator for events with no cgroup.
908 for (heap_size = 1; css; css = css->parent)
911 for_each_possible_cpu(cpu) {
912 cpuctx = per_cpu_ptr(event->pmu->pmu_cpu_context, cpu);
913 if (heap_size <= cpuctx->heap_size)
916 storage = kmalloc_node(heap_size * sizeof(struct perf_event *),
917 GFP_KERNEL, cpu_to_node(cpu));
923 raw_spin_lock_irq(&cpuctx->ctx.lock);
924 if (cpuctx->heap_size < heap_size) {
925 swap(cpuctx->heap, storage);
926 if (storage == cpuctx->heap_default)
928 cpuctx->heap_size = heap_size;
930 raw_spin_unlock_irq(&cpuctx->ctx.lock);
938 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
939 struct perf_event_attr *attr,
940 struct perf_event *group_leader)
942 struct perf_cgroup *cgrp;
943 struct cgroup_subsys_state *css;
944 struct fd f = fdget(fd);
950 css = css_tryget_online_from_dir(f.file->f_path.dentry,
951 &perf_event_cgrp_subsys);
957 ret = perf_cgroup_ensure_storage(event, css);
961 cgrp = container_of(css, struct perf_cgroup, css);
965 * all events in a group must monitor
966 * the same cgroup because a task belongs
967 * to only one perf cgroup at a time
969 if (group_leader && group_leader->cgrp != cgrp) {
970 perf_detach_cgroup(event);
979 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
981 struct perf_cgroup_info *t;
982 t = per_cpu_ptr(event->cgrp->info, event->cpu);
983 event->shadow_ctx_time = now - t->timestamp;
987 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
988 * cleared when last cgroup event is removed.
991 list_update_cgroup_event(struct perf_event *event,
992 struct perf_event_context *ctx, bool add)
994 struct perf_cpu_context *cpuctx;
995 struct list_head *cpuctx_entry;
997 if (!is_cgroup_event(event))
1001 * Because cgroup events are always per-cpu events,
1002 * @ctx == &cpuctx->ctx.
1004 cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
1007 * Since setting cpuctx->cgrp is conditional on the current @cgrp
1008 * matching the event's cgroup, we must do this for every new event,
1009 * because if the first would mismatch, the second would not try again
1010 * and we would leave cpuctx->cgrp unset.
1012 if (add && !cpuctx->cgrp) {
1013 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
1015 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
1016 cpuctx->cgrp = cgrp;
1019 if (add && ctx->nr_cgroups++)
1021 else if (!add && --ctx->nr_cgroups)
1024 /* no cgroup running */
1026 cpuctx->cgrp = NULL;
1028 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
1030 list_add(cpuctx_entry,
1031 per_cpu_ptr(&cgrp_cpuctx_list, event->cpu));
1033 list_del(cpuctx_entry);
1036 #else /* !CONFIG_CGROUP_PERF */
1039 perf_cgroup_match(struct perf_event *event)
1044 static inline void perf_detach_cgroup(struct perf_event *event)
1047 static inline int is_cgroup_event(struct perf_event *event)
1052 static inline void update_cgrp_time_from_event(struct perf_event *event)
1056 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
1060 static inline void perf_cgroup_sched_out(struct task_struct *task,
1061 struct task_struct *next)
1065 static inline void perf_cgroup_sched_in(struct task_struct *prev,
1066 struct task_struct *task)
1070 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1071 struct perf_event_attr *attr,
1072 struct perf_event *group_leader)
1078 perf_cgroup_set_timestamp(struct task_struct *task,
1079 struct perf_event_context *ctx)
1084 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1089 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1093 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1099 list_update_cgroup_event(struct perf_event *event,
1100 struct perf_event_context *ctx, bool add)
1107 * set default to be dependent on timer tick just
1108 * like original code
1110 #define PERF_CPU_HRTIMER (1000 / HZ)
1112 * function must be called with interrupts disabled
1114 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1116 struct perf_cpu_context *cpuctx;
1119 lockdep_assert_irqs_disabled();
1121 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1122 rotations = perf_rotate_context(cpuctx);
1124 raw_spin_lock(&cpuctx->hrtimer_lock);
1126 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1128 cpuctx->hrtimer_active = 0;
1129 raw_spin_unlock(&cpuctx->hrtimer_lock);
1131 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1134 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1136 struct hrtimer *timer = &cpuctx->hrtimer;
1137 struct pmu *pmu = cpuctx->ctx.pmu;
1140 /* no multiplexing needed for SW PMU */
1141 if (pmu->task_ctx_nr == perf_sw_context)
1145 * check default is sane, if not set then force to
1146 * default interval (1/tick)
1148 interval = pmu->hrtimer_interval_ms;
1150 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1152 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1154 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1155 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
1156 timer->function = perf_mux_hrtimer_handler;
1159 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1161 struct hrtimer *timer = &cpuctx->hrtimer;
1162 struct pmu *pmu = cpuctx->ctx.pmu;
1163 unsigned long flags;
1165 /* not for SW PMU */
1166 if (pmu->task_ctx_nr == perf_sw_context)
1169 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1170 if (!cpuctx->hrtimer_active) {
1171 cpuctx->hrtimer_active = 1;
1172 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1173 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
1175 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1180 void perf_pmu_disable(struct pmu *pmu)
1182 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1184 pmu->pmu_disable(pmu);
1187 void perf_pmu_enable(struct pmu *pmu)
1189 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1191 pmu->pmu_enable(pmu);
1194 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1197 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1198 * perf_event_task_tick() are fully serialized because they're strictly cpu
1199 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1200 * disabled, while perf_event_task_tick is called from IRQ context.
1202 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1204 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1206 lockdep_assert_irqs_disabled();
1208 WARN_ON(!list_empty(&ctx->active_ctx_list));
1210 list_add(&ctx->active_ctx_list, head);
1213 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1215 lockdep_assert_irqs_disabled();
1217 WARN_ON(list_empty(&ctx->active_ctx_list));
1219 list_del_init(&ctx->active_ctx_list);
1222 static void get_ctx(struct perf_event_context *ctx)
1224 refcount_inc(&ctx->refcount);
1227 static void free_ctx(struct rcu_head *head)
1229 struct perf_event_context *ctx;
1231 ctx = container_of(head, struct perf_event_context, rcu_head);
1232 kfree(ctx->task_ctx_data);
1236 static void put_ctx(struct perf_event_context *ctx)
1238 if (refcount_dec_and_test(&ctx->refcount)) {
1239 if (ctx->parent_ctx)
1240 put_ctx(ctx->parent_ctx);
1241 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1242 put_task_struct(ctx->task);
1243 call_rcu(&ctx->rcu_head, free_ctx);
1248 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1249 * perf_pmu_migrate_context() we need some magic.
1251 * Those places that change perf_event::ctx will hold both
1252 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1254 * Lock ordering is by mutex address. There are two other sites where
1255 * perf_event_context::mutex nests and those are:
1257 * - perf_event_exit_task_context() [ child , 0 ]
1258 * perf_event_exit_event()
1259 * put_event() [ parent, 1 ]
1261 * - perf_event_init_context() [ parent, 0 ]
1262 * inherit_task_group()
1265 * perf_event_alloc()
1267 * perf_try_init_event() [ child , 1 ]
1269 * While it appears there is an obvious deadlock here -- the parent and child
1270 * nesting levels are inverted between the two. This is in fact safe because
1271 * life-time rules separate them. That is an exiting task cannot fork, and a
1272 * spawning task cannot (yet) exit.
1274 * But remember that that these are parent<->child context relations, and
1275 * migration does not affect children, therefore these two orderings should not
1278 * The change in perf_event::ctx does not affect children (as claimed above)
1279 * because the sys_perf_event_open() case will install a new event and break
1280 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1281 * concerned with cpuctx and that doesn't have children.
1283 * The places that change perf_event::ctx will issue:
1285 * perf_remove_from_context();
1286 * synchronize_rcu();
1287 * perf_install_in_context();
1289 * to affect the change. The remove_from_context() + synchronize_rcu() should
1290 * quiesce the event, after which we can install it in the new location. This
1291 * means that only external vectors (perf_fops, prctl) can perturb the event
1292 * while in transit. Therefore all such accessors should also acquire
1293 * perf_event_context::mutex to serialize against this.
1295 * However; because event->ctx can change while we're waiting to acquire
1296 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1301 * task_struct::perf_event_mutex
1302 * perf_event_context::mutex
1303 * perf_event::child_mutex;
1304 * perf_event_context::lock
1305 * perf_event::mmap_mutex
1307 * perf_addr_filters_head::lock
1311 * cpuctx->mutex / perf_event_context::mutex
1313 static struct perf_event_context *
1314 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1316 struct perf_event_context *ctx;
1320 ctx = READ_ONCE(event->ctx);
1321 if (!refcount_inc_not_zero(&ctx->refcount)) {
1327 mutex_lock_nested(&ctx->mutex, nesting);
1328 if (event->ctx != ctx) {
1329 mutex_unlock(&ctx->mutex);
1337 static inline struct perf_event_context *
1338 perf_event_ctx_lock(struct perf_event *event)
1340 return perf_event_ctx_lock_nested(event, 0);
1343 static void perf_event_ctx_unlock(struct perf_event *event,
1344 struct perf_event_context *ctx)
1346 mutex_unlock(&ctx->mutex);
1351 * This must be done under the ctx->lock, such as to serialize against
1352 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1353 * calling scheduler related locks and ctx->lock nests inside those.
1355 static __must_check struct perf_event_context *
1356 unclone_ctx(struct perf_event_context *ctx)
1358 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1360 lockdep_assert_held(&ctx->lock);
1363 ctx->parent_ctx = NULL;
1369 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1374 * only top level events have the pid namespace they were created in
1377 event = event->parent;
1379 nr = __task_pid_nr_ns(p, type, event->ns);
1380 /* avoid -1 if it is idle thread or runs in another ns */
1381 if (!nr && !pid_alive(p))
1386 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1388 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1391 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1393 return perf_event_pid_type(event, p, PIDTYPE_PID);
1397 * If we inherit events we want to return the parent event id
1400 static u64 primary_event_id(struct perf_event *event)
1405 id = event->parent->id;
1411 * Get the perf_event_context for a task and lock it.
1413 * This has to cope with with the fact that until it is locked,
1414 * the context could get moved to another task.
1416 static struct perf_event_context *
1417 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1419 struct perf_event_context *ctx;
1423 * One of the few rules of preemptible RCU is that one cannot do
1424 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1425 * part of the read side critical section was irqs-enabled -- see
1426 * rcu_read_unlock_special().
1428 * Since ctx->lock nests under rq->lock we must ensure the entire read
1429 * side critical section has interrupts disabled.
1431 local_irq_save(*flags);
1433 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1436 * If this context is a clone of another, it might
1437 * get swapped for another underneath us by
1438 * perf_event_task_sched_out, though the
1439 * rcu_read_lock() protects us from any context
1440 * getting freed. Lock the context and check if it
1441 * got swapped before we could get the lock, and retry
1442 * if so. If we locked the right context, then it
1443 * can't get swapped on us any more.
1445 raw_spin_lock(&ctx->lock);
1446 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1447 raw_spin_unlock(&ctx->lock);
1449 local_irq_restore(*flags);
1453 if (ctx->task == TASK_TOMBSTONE ||
1454 !refcount_inc_not_zero(&ctx->refcount)) {
1455 raw_spin_unlock(&ctx->lock);
1458 WARN_ON_ONCE(ctx->task != task);
1463 local_irq_restore(*flags);
1468 * Get the context for a task and increment its pin_count so it
1469 * can't get swapped to another task. This also increments its
1470 * reference count so that the context can't get freed.
1472 static struct perf_event_context *
1473 perf_pin_task_context(struct task_struct *task, int ctxn)
1475 struct perf_event_context *ctx;
1476 unsigned long flags;
1478 ctx = perf_lock_task_context(task, ctxn, &flags);
1481 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1486 static void perf_unpin_context(struct perf_event_context *ctx)
1488 unsigned long flags;
1490 raw_spin_lock_irqsave(&ctx->lock, flags);
1492 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1496 * Update the record of the current time in a context.
1498 static void update_context_time(struct perf_event_context *ctx)
1500 u64 now = perf_clock();
1502 ctx->time += now - ctx->timestamp;
1503 ctx->timestamp = now;
1506 static u64 perf_event_time(struct perf_event *event)
1508 struct perf_event_context *ctx = event->ctx;
1510 if (is_cgroup_event(event))
1511 return perf_cgroup_event_time(event);
1513 return ctx ? ctx->time : 0;
1516 static enum event_type_t get_event_type(struct perf_event *event)
1518 struct perf_event_context *ctx = event->ctx;
1519 enum event_type_t event_type;
1521 lockdep_assert_held(&ctx->lock);
1524 * It's 'group type', really, because if our group leader is
1525 * pinned, so are we.
1527 if (event->group_leader != event)
1528 event = event->group_leader;
1530 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1532 event_type |= EVENT_CPU;
1538 * Helper function to initialize event group nodes.
1540 static void init_event_group(struct perf_event *event)
1542 RB_CLEAR_NODE(&event->group_node);
1543 event->group_index = 0;
1547 * Extract pinned or flexible groups from the context
1548 * based on event attrs bits.
1550 static struct perf_event_groups *
1551 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1553 if (event->attr.pinned)
1554 return &ctx->pinned_groups;
1556 return &ctx->flexible_groups;
1560 * Helper function to initializes perf_event_group trees.
1562 static void perf_event_groups_init(struct perf_event_groups *groups)
1564 groups->tree = RB_ROOT;
1569 * Compare function for event groups;
1571 * Implements complex key that first sorts by CPU and then by virtual index
1572 * which provides ordering when rotating groups for the same CPU.
1575 perf_event_groups_less(struct perf_event *left, struct perf_event *right)
1577 if (left->cpu < right->cpu)
1579 if (left->cpu > right->cpu)
1582 #ifdef CONFIG_CGROUP_PERF
1583 if (left->cgrp != right->cgrp) {
1584 if (!left->cgrp || !left->cgrp->css.cgroup) {
1586 * Left has no cgroup but right does, no cgroups come
1591 if (!right->cgrp || !right->cgrp->css.cgroup) {
1593 * Right has no cgroup but left does, no cgroups come
1598 /* Two dissimilar cgroups, order by id. */
1599 if (left->cgrp->css.cgroup->kn->id < right->cgrp->css.cgroup->kn->id)
1606 if (left->group_index < right->group_index)
1608 if (left->group_index > right->group_index)
1615 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1616 * key (see perf_event_groups_less). This places it last inside the CPU
1620 perf_event_groups_insert(struct perf_event_groups *groups,
1621 struct perf_event *event)
1623 struct perf_event *node_event;
1624 struct rb_node *parent;
1625 struct rb_node **node;
1627 event->group_index = ++groups->index;
1629 node = &groups->tree.rb_node;
1634 node_event = container_of(*node, struct perf_event, group_node);
1636 if (perf_event_groups_less(event, node_event))
1637 node = &parent->rb_left;
1639 node = &parent->rb_right;
1642 rb_link_node(&event->group_node, parent, node);
1643 rb_insert_color(&event->group_node, &groups->tree);
1647 * Helper function to insert event into the pinned or flexible groups.
1650 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1652 struct perf_event_groups *groups;
1654 groups = get_event_groups(event, ctx);
1655 perf_event_groups_insert(groups, event);
1659 * Delete a group from a tree.
1662 perf_event_groups_delete(struct perf_event_groups *groups,
1663 struct perf_event *event)
1665 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1666 RB_EMPTY_ROOT(&groups->tree));
1668 rb_erase(&event->group_node, &groups->tree);
1669 init_event_group(event);
1673 * Helper function to delete event from its groups.
1676 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1678 struct perf_event_groups *groups;
1680 groups = get_event_groups(event, ctx);
1681 perf_event_groups_delete(groups, event);
1685 * Get the leftmost event in the cpu/cgroup subtree.
1687 static struct perf_event *
1688 perf_event_groups_first(struct perf_event_groups *groups, int cpu,
1689 struct cgroup *cgrp)
1691 struct perf_event *node_event = NULL, *match = NULL;
1692 struct rb_node *node = groups->tree.rb_node;
1693 #ifdef CONFIG_CGROUP_PERF
1694 u64 node_cgrp_id, cgrp_id = 0;
1697 cgrp_id = cgrp->kn->id;
1701 node_event = container_of(node, struct perf_event, group_node);
1703 if (cpu < node_event->cpu) {
1704 node = node->rb_left;
1707 if (cpu > node_event->cpu) {
1708 node = node->rb_right;
1711 #ifdef CONFIG_CGROUP_PERF
1713 if (node_event->cgrp && node_event->cgrp->css.cgroup)
1714 node_cgrp_id = node_event->cgrp->css.cgroup->kn->id;
1716 if (cgrp_id < node_cgrp_id) {
1717 node = node->rb_left;
1720 if (cgrp_id > node_cgrp_id) {
1721 node = node->rb_right;
1726 node = node->rb_left;
1733 * Like rb_entry_next_safe() for the @cpu subtree.
1735 static struct perf_event *
1736 perf_event_groups_next(struct perf_event *event)
1738 struct perf_event *next;
1739 #ifdef CONFIG_CGROUP_PERF
1740 u64 curr_cgrp_id = 0;
1741 u64 next_cgrp_id = 0;
1744 next = rb_entry_safe(rb_next(&event->group_node), typeof(*event), group_node);
1745 if (next == NULL || next->cpu != event->cpu)
1748 #ifdef CONFIG_CGROUP_PERF
1749 if (event->cgrp && event->cgrp->css.cgroup)
1750 curr_cgrp_id = event->cgrp->css.cgroup->kn->id;
1752 if (next->cgrp && next->cgrp->css.cgroup)
1753 next_cgrp_id = next->cgrp->css.cgroup->kn->id;
1755 if (curr_cgrp_id != next_cgrp_id)
1762 * Iterate through the whole groups tree.
1764 #define perf_event_groups_for_each(event, groups) \
1765 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1766 typeof(*event), group_node); event; \
1767 event = rb_entry_safe(rb_next(&event->group_node), \
1768 typeof(*event), group_node))
1771 * Add an event from the lists for its context.
1772 * Must be called with ctx->mutex and ctx->lock held.
1775 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1777 lockdep_assert_held(&ctx->lock);
1779 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1780 event->attach_state |= PERF_ATTACH_CONTEXT;
1782 event->tstamp = perf_event_time(event);
1785 * If we're a stand alone event or group leader, we go to the context
1786 * list, group events are kept attached to the group so that
1787 * perf_group_detach can, at all times, locate all siblings.
1789 if (event->group_leader == event) {
1790 event->group_caps = event->event_caps;
1791 add_event_to_groups(event, ctx);
1794 list_update_cgroup_event(event, ctx, true);
1796 list_add_rcu(&event->event_entry, &ctx->event_list);
1798 if (event->attr.inherit_stat)
1805 * Initialize event state based on the perf_event_attr::disabled.
1807 static inline void perf_event__state_init(struct perf_event *event)
1809 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1810 PERF_EVENT_STATE_INACTIVE;
1813 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1815 int entry = sizeof(u64); /* value */
1819 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1820 size += sizeof(u64);
1822 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1823 size += sizeof(u64);
1825 if (event->attr.read_format & PERF_FORMAT_ID)
1826 entry += sizeof(u64);
1828 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1830 size += sizeof(u64);
1834 event->read_size = size;
1837 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1839 struct perf_sample_data *data;
1842 if (sample_type & PERF_SAMPLE_IP)
1843 size += sizeof(data->ip);
1845 if (sample_type & PERF_SAMPLE_ADDR)
1846 size += sizeof(data->addr);
1848 if (sample_type & PERF_SAMPLE_PERIOD)
1849 size += sizeof(data->period);
1851 if (sample_type & PERF_SAMPLE_WEIGHT)
1852 size += sizeof(data->weight);
1854 if (sample_type & PERF_SAMPLE_READ)
1855 size += event->read_size;
1857 if (sample_type & PERF_SAMPLE_DATA_SRC)
1858 size += sizeof(data->data_src.val);
1860 if (sample_type & PERF_SAMPLE_TRANSACTION)
1861 size += sizeof(data->txn);
1863 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1864 size += sizeof(data->phys_addr);
1866 if (sample_type & PERF_SAMPLE_CGROUP)
1867 size += sizeof(data->cgroup);
1869 event->header_size = size;
1873 * Called at perf_event creation and when events are attached/detached from a
1876 static void perf_event__header_size(struct perf_event *event)
1878 __perf_event_read_size(event,
1879 event->group_leader->nr_siblings);
1880 __perf_event_header_size(event, event->attr.sample_type);
1883 static void perf_event__id_header_size(struct perf_event *event)
1885 struct perf_sample_data *data;
1886 u64 sample_type = event->attr.sample_type;
1889 if (sample_type & PERF_SAMPLE_TID)
1890 size += sizeof(data->tid_entry);
1892 if (sample_type & PERF_SAMPLE_TIME)
1893 size += sizeof(data->time);
1895 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1896 size += sizeof(data->id);
1898 if (sample_type & PERF_SAMPLE_ID)
1899 size += sizeof(data->id);
1901 if (sample_type & PERF_SAMPLE_STREAM_ID)
1902 size += sizeof(data->stream_id);
1904 if (sample_type & PERF_SAMPLE_CPU)
1905 size += sizeof(data->cpu_entry);
1907 event->id_header_size = size;
1910 static bool perf_event_validate_size(struct perf_event *event)
1913 * The values computed here will be over-written when we actually
1916 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1917 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1918 perf_event__id_header_size(event);
1921 * Sum the lot; should not exceed the 64k limit we have on records.
1922 * Conservative limit to allow for callchains and other variable fields.
1924 if (event->read_size + event->header_size +
1925 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1931 static void perf_group_attach(struct perf_event *event)
1933 struct perf_event *group_leader = event->group_leader, *pos;
1935 lockdep_assert_held(&event->ctx->lock);
1938 * We can have double attach due to group movement in perf_event_open.
1940 if (event->attach_state & PERF_ATTACH_GROUP)
1943 event->attach_state |= PERF_ATTACH_GROUP;
1945 if (group_leader == event)
1948 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1950 group_leader->group_caps &= event->event_caps;
1952 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1953 group_leader->nr_siblings++;
1955 perf_event__header_size(group_leader);
1957 for_each_sibling_event(pos, group_leader)
1958 perf_event__header_size(pos);
1962 * Remove an event from the lists for its context.
1963 * Must be called with ctx->mutex and ctx->lock held.
1966 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1968 WARN_ON_ONCE(event->ctx != ctx);
1969 lockdep_assert_held(&ctx->lock);
1972 * We can have double detach due to exit/hot-unplug + close.
1974 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1977 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1979 list_update_cgroup_event(event, ctx, false);
1982 if (event->attr.inherit_stat)
1985 list_del_rcu(&event->event_entry);
1987 if (event->group_leader == event)
1988 del_event_from_groups(event, ctx);
1991 * If event was in error state, then keep it
1992 * that way, otherwise bogus counts will be
1993 * returned on read(). The only way to get out
1994 * of error state is by explicit re-enabling
1997 if (event->state > PERF_EVENT_STATE_OFF)
1998 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2004 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
2006 if (!has_aux(aux_event))
2009 if (!event->pmu->aux_output_match)
2012 return event->pmu->aux_output_match(aux_event);
2015 static void put_event(struct perf_event *event);
2016 static void event_sched_out(struct perf_event *event,
2017 struct perf_cpu_context *cpuctx,
2018 struct perf_event_context *ctx);
2020 static void perf_put_aux_event(struct perf_event *event)
2022 struct perf_event_context *ctx = event->ctx;
2023 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2024 struct perf_event *iter;
2027 * If event uses aux_event tear down the link
2029 if (event->aux_event) {
2030 iter = event->aux_event;
2031 event->aux_event = NULL;
2037 * If the event is an aux_event, tear down all links to
2038 * it from other events.
2040 for_each_sibling_event(iter, event->group_leader) {
2041 if (iter->aux_event != event)
2044 iter->aux_event = NULL;
2048 * If it's ACTIVE, schedule it out and put it into ERROR
2049 * state so that we don't try to schedule it again. Note
2050 * that perf_event_enable() will clear the ERROR status.
2052 event_sched_out(iter, cpuctx, ctx);
2053 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2057 static bool perf_need_aux_event(struct perf_event *event)
2059 return !!event->attr.aux_output || !!event->attr.aux_sample_size;
2062 static int perf_get_aux_event(struct perf_event *event,
2063 struct perf_event *group_leader)
2066 * Our group leader must be an aux event if we want to be
2067 * an aux_output. This way, the aux event will precede its
2068 * aux_output events in the group, and therefore will always
2075 * aux_output and aux_sample_size are mutually exclusive.
2077 if (event->attr.aux_output && event->attr.aux_sample_size)
2080 if (event->attr.aux_output &&
2081 !perf_aux_output_match(event, group_leader))
2084 if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux)
2087 if (!atomic_long_inc_not_zero(&group_leader->refcount))
2091 * Link aux_outputs to their aux event; this is undone in
2092 * perf_group_detach() by perf_put_aux_event(). When the
2093 * group in torn down, the aux_output events loose their
2094 * link to the aux_event and can't schedule any more.
2096 event->aux_event = group_leader;
2101 static inline struct list_head *get_event_list(struct perf_event *event)
2103 struct perf_event_context *ctx = event->ctx;
2104 return event->attr.pinned ? &ctx->pinned_active : &ctx->flexible_active;
2107 static void perf_group_detach(struct perf_event *event)
2109 struct perf_event *sibling, *tmp;
2110 struct perf_event_context *ctx = event->ctx;
2112 lockdep_assert_held(&ctx->lock);
2115 * We can have double detach due to exit/hot-unplug + close.
2117 if (!(event->attach_state & PERF_ATTACH_GROUP))
2120 event->attach_state &= ~PERF_ATTACH_GROUP;
2122 perf_put_aux_event(event);
2125 * If this is a sibling, remove it from its group.
2127 if (event->group_leader != event) {
2128 list_del_init(&event->sibling_list);
2129 event->group_leader->nr_siblings--;
2134 * If this was a group event with sibling events then
2135 * upgrade the siblings to singleton events by adding them
2136 * to whatever list we are on.
2138 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
2140 sibling->group_leader = sibling;
2141 list_del_init(&sibling->sibling_list);
2143 /* Inherit group flags from the previous leader */
2144 sibling->group_caps = event->group_caps;
2146 if (!RB_EMPTY_NODE(&event->group_node)) {
2147 add_event_to_groups(sibling, event->ctx);
2149 if (sibling->state == PERF_EVENT_STATE_ACTIVE)
2150 list_add_tail(&sibling->active_list, get_event_list(sibling));
2153 WARN_ON_ONCE(sibling->ctx != event->ctx);
2157 perf_event__header_size(event->group_leader);
2159 for_each_sibling_event(tmp, event->group_leader)
2160 perf_event__header_size(tmp);
2163 static bool is_orphaned_event(struct perf_event *event)
2165 return event->state == PERF_EVENT_STATE_DEAD;
2168 static inline int __pmu_filter_match(struct perf_event *event)
2170 struct pmu *pmu = event->pmu;
2171 return pmu->filter_match ? pmu->filter_match(event) : 1;
2175 * Check whether we should attempt to schedule an event group based on
2176 * PMU-specific filtering. An event group can consist of HW and SW events,
2177 * potentially with a SW leader, so we must check all the filters, to
2178 * determine whether a group is schedulable:
2180 static inline int pmu_filter_match(struct perf_event *event)
2182 struct perf_event *sibling;
2184 if (!__pmu_filter_match(event))
2187 for_each_sibling_event(sibling, event) {
2188 if (!__pmu_filter_match(sibling))
2196 event_filter_match(struct perf_event *event)
2198 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2199 perf_cgroup_match(event) && pmu_filter_match(event);
2203 event_sched_out(struct perf_event *event,
2204 struct perf_cpu_context *cpuctx,
2205 struct perf_event_context *ctx)
2207 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2209 WARN_ON_ONCE(event->ctx != ctx);
2210 lockdep_assert_held(&ctx->lock);
2212 if (event->state != PERF_EVENT_STATE_ACTIVE)
2216 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2217 * we can schedule events _OUT_ individually through things like
2218 * __perf_remove_from_context().
2220 list_del_init(&event->active_list);
2222 perf_pmu_disable(event->pmu);
2224 event->pmu->del(event, 0);
2227 if (READ_ONCE(event->pending_disable) >= 0) {
2228 WRITE_ONCE(event->pending_disable, -1);
2229 state = PERF_EVENT_STATE_OFF;
2231 perf_event_set_state(event, state);
2233 if (!is_software_event(event))
2234 cpuctx->active_oncpu--;
2235 if (!--ctx->nr_active)
2236 perf_event_ctx_deactivate(ctx);
2237 if (event->attr.freq && event->attr.sample_freq)
2239 if (event->attr.exclusive || !cpuctx->active_oncpu)
2240 cpuctx->exclusive = 0;
2242 perf_pmu_enable(event->pmu);
2246 group_sched_out(struct perf_event *group_event,
2247 struct perf_cpu_context *cpuctx,
2248 struct perf_event_context *ctx)
2250 struct perf_event *event;
2252 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2255 perf_pmu_disable(ctx->pmu);
2257 event_sched_out(group_event, cpuctx, ctx);
2260 * Schedule out siblings (if any):
2262 for_each_sibling_event(event, group_event)
2263 event_sched_out(event, cpuctx, ctx);
2265 perf_pmu_enable(ctx->pmu);
2267 if (group_event->attr.exclusive)
2268 cpuctx->exclusive = 0;
2271 #define DETACH_GROUP 0x01UL
2274 * Cross CPU call to remove a performance event
2276 * We disable the event on the hardware level first. After that we
2277 * remove it from the context list.
2280 __perf_remove_from_context(struct perf_event *event,
2281 struct perf_cpu_context *cpuctx,
2282 struct perf_event_context *ctx,
2285 unsigned long flags = (unsigned long)info;
2287 if (ctx->is_active & EVENT_TIME) {
2288 update_context_time(ctx);
2289 update_cgrp_time_from_cpuctx(cpuctx);
2292 event_sched_out(event, cpuctx, ctx);
2293 if (flags & DETACH_GROUP)
2294 perf_group_detach(event);
2295 list_del_event(event, ctx);
2297 if (!ctx->nr_events && ctx->is_active) {
2299 ctx->rotate_necessary = 0;
2301 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2302 cpuctx->task_ctx = NULL;
2308 * Remove the event from a task's (or a CPU's) list of events.
2310 * If event->ctx is a cloned context, callers must make sure that
2311 * every task struct that event->ctx->task could possibly point to
2312 * remains valid. This is OK when called from perf_release since
2313 * that only calls us on the top-level context, which can't be a clone.
2314 * When called from perf_event_exit_task, it's OK because the
2315 * context has been detached from its task.
2317 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2319 struct perf_event_context *ctx = event->ctx;
2321 lockdep_assert_held(&ctx->mutex);
2323 event_function_call(event, __perf_remove_from_context, (void *)flags);
2326 * The above event_function_call() can NO-OP when it hits
2327 * TASK_TOMBSTONE. In that case we must already have been detached
2328 * from the context (by perf_event_exit_event()) but the grouping
2329 * might still be in-tact.
2331 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
2332 if ((flags & DETACH_GROUP) &&
2333 (event->attach_state & PERF_ATTACH_GROUP)) {
2335 * Since in that case we cannot possibly be scheduled, simply
2338 raw_spin_lock_irq(&ctx->lock);
2339 perf_group_detach(event);
2340 raw_spin_unlock_irq(&ctx->lock);
2345 * Cross CPU call to disable a performance event
2347 static void __perf_event_disable(struct perf_event *event,
2348 struct perf_cpu_context *cpuctx,
2349 struct perf_event_context *ctx,
2352 if (event->state < PERF_EVENT_STATE_INACTIVE)
2355 if (ctx->is_active & EVENT_TIME) {
2356 update_context_time(ctx);
2357 update_cgrp_time_from_event(event);
2360 if (event == event->group_leader)
2361 group_sched_out(event, cpuctx, ctx);
2363 event_sched_out(event, cpuctx, ctx);
2365 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2371 * If event->ctx is a cloned context, callers must make sure that
2372 * every task struct that event->ctx->task could possibly point to
2373 * remains valid. This condition is satisfied when called through
2374 * perf_event_for_each_child or perf_event_for_each because they
2375 * hold the top-level event's child_mutex, so any descendant that
2376 * goes to exit will block in perf_event_exit_event().
2378 * When called from perf_pending_event it's OK because event->ctx
2379 * is the current context on this CPU and preemption is disabled,
2380 * hence we can't get into perf_event_task_sched_out for this context.
2382 static void _perf_event_disable(struct perf_event *event)
2384 struct perf_event_context *ctx = event->ctx;
2386 raw_spin_lock_irq(&ctx->lock);
2387 if (event->state <= PERF_EVENT_STATE_OFF) {
2388 raw_spin_unlock_irq(&ctx->lock);
2391 raw_spin_unlock_irq(&ctx->lock);
2393 event_function_call(event, __perf_event_disable, NULL);
2396 void perf_event_disable_local(struct perf_event *event)
2398 event_function_local(event, __perf_event_disable, NULL);
2402 * Strictly speaking kernel users cannot create groups and therefore this
2403 * interface does not need the perf_event_ctx_lock() magic.
2405 void perf_event_disable(struct perf_event *event)
2407 struct perf_event_context *ctx;
2409 ctx = perf_event_ctx_lock(event);
2410 _perf_event_disable(event);
2411 perf_event_ctx_unlock(event, ctx);
2413 EXPORT_SYMBOL_GPL(perf_event_disable);
2415 void perf_event_disable_inatomic(struct perf_event *event)
2417 WRITE_ONCE(event->pending_disable, smp_processor_id());
2418 /* can fail, see perf_pending_event_disable() */
2419 irq_work_queue(&event->pending);
2422 static void perf_set_shadow_time(struct perf_event *event,
2423 struct perf_event_context *ctx)
2426 * use the correct time source for the time snapshot
2428 * We could get by without this by leveraging the
2429 * fact that to get to this function, the caller
2430 * has most likely already called update_context_time()
2431 * and update_cgrp_time_xx() and thus both timestamp
2432 * are identical (or very close). Given that tstamp is,
2433 * already adjusted for cgroup, we could say that:
2434 * tstamp - ctx->timestamp
2436 * tstamp - cgrp->timestamp.
2438 * Then, in perf_output_read(), the calculation would
2439 * work with no changes because:
2440 * - event is guaranteed scheduled in
2441 * - no scheduled out in between
2442 * - thus the timestamp would be the same
2444 * But this is a bit hairy.
2446 * So instead, we have an explicit cgroup call to remain
2447 * within the time time source all along. We believe it
2448 * is cleaner and simpler to understand.
2450 if (is_cgroup_event(event))
2451 perf_cgroup_set_shadow_time(event, event->tstamp);
2453 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2456 #define MAX_INTERRUPTS (~0ULL)
2458 static void perf_log_throttle(struct perf_event *event, int enable);
2459 static void perf_log_itrace_start(struct perf_event *event);
2462 event_sched_in(struct perf_event *event,
2463 struct perf_cpu_context *cpuctx,
2464 struct perf_event_context *ctx)
2468 WARN_ON_ONCE(event->ctx != ctx);
2470 lockdep_assert_held(&ctx->lock);
2472 if (event->state <= PERF_EVENT_STATE_OFF)
2475 WRITE_ONCE(event->oncpu, smp_processor_id());
2477 * Order event::oncpu write to happen before the ACTIVE state is
2478 * visible. This allows perf_event_{stop,read}() to observe the correct
2479 * ->oncpu if it sees ACTIVE.
2482 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2485 * Unthrottle events, since we scheduled we might have missed several
2486 * ticks already, also for a heavily scheduling task there is little
2487 * guarantee it'll get a tick in a timely manner.
2489 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2490 perf_log_throttle(event, 1);
2491 event->hw.interrupts = 0;
2494 perf_pmu_disable(event->pmu);
2496 perf_set_shadow_time(event, ctx);
2498 perf_log_itrace_start(event);
2500 if (event->pmu->add(event, PERF_EF_START)) {
2501 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2507 if (!is_software_event(event))
2508 cpuctx->active_oncpu++;
2509 if (!ctx->nr_active++)
2510 perf_event_ctx_activate(ctx);
2511 if (event->attr.freq && event->attr.sample_freq)
2514 if (event->attr.exclusive)
2515 cpuctx->exclusive = 1;
2518 perf_pmu_enable(event->pmu);
2524 group_sched_in(struct perf_event *group_event,
2525 struct perf_cpu_context *cpuctx,
2526 struct perf_event_context *ctx)
2528 struct perf_event *event, *partial_group = NULL;
2529 struct pmu *pmu = ctx->pmu;
2531 if (group_event->state == PERF_EVENT_STATE_OFF)
2534 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2536 if (event_sched_in(group_event, cpuctx, ctx)) {
2537 pmu->cancel_txn(pmu);
2538 perf_mux_hrtimer_restart(cpuctx);
2543 * Schedule in siblings as one group (if any):
2545 for_each_sibling_event(event, group_event) {
2546 if (event_sched_in(event, cpuctx, ctx)) {
2547 partial_group = event;
2552 if (!pmu->commit_txn(pmu))
2557 * Groups can be scheduled in as one unit only, so undo any
2558 * partial group before returning:
2559 * The events up to the failed event are scheduled out normally.
2561 for_each_sibling_event(event, group_event) {
2562 if (event == partial_group)
2565 event_sched_out(event, cpuctx, ctx);
2567 event_sched_out(group_event, cpuctx, ctx);
2569 pmu->cancel_txn(pmu);
2571 perf_mux_hrtimer_restart(cpuctx);
2577 * Work out whether we can put this event group on the CPU now.
2579 static int group_can_go_on(struct perf_event *event,
2580 struct perf_cpu_context *cpuctx,
2584 * Groups consisting entirely of software events can always go on.
2586 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2589 * If an exclusive group is already on, no other hardware
2592 if (cpuctx->exclusive)
2595 * If this group is exclusive and there are already
2596 * events on the CPU, it can't go on.
2598 if (event->attr.exclusive && cpuctx->active_oncpu)
2601 * Otherwise, try to add it if all previous groups were able
2607 static void add_event_to_ctx(struct perf_event *event,
2608 struct perf_event_context *ctx)
2610 list_add_event(event, ctx);
2611 perf_group_attach(event);
2614 static void ctx_sched_out(struct perf_event_context *ctx,
2615 struct perf_cpu_context *cpuctx,
2616 enum event_type_t event_type);
2618 ctx_sched_in(struct perf_event_context *ctx,
2619 struct perf_cpu_context *cpuctx,
2620 enum event_type_t event_type,
2621 struct task_struct *task);
2623 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2624 struct perf_event_context *ctx,
2625 enum event_type_t event_type)
2627 if (!cpuctx->task_ctx)
2630 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2633 ctx_sched_out(ctx, cpuctx, event_type);
2636 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2637 struct perf_event_context *ctx,
2638 struct task_struct *task)
2640 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2642 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2643 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2645 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2649 * We want to maintain the following priority of scheduling:
2650 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2651 * - task pinned (EVENT_PINNED)
2652 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2653 * - task flexible (EVENT_FLEXIBLE).
2655 * In order to avoid unscheduling and scheduling back in everything every
2656 * time an event is added, only do it for the groups of equal priority and
2659 * This can be called after a batch operation on task events, in which case
2660 * event_type is a bit mask of the types of events involved. For CPU events,
2661 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2663 static void ctx_resched(struct perf_cpu_context *cpuctx,
2664 struct perf_event_context *task_ctx,
2665 enum event_type_t event_type)
2667 enum event_type_t ctx_event_type;
2668 bool cpu_event = !!(event_type & EVENT_CPU);
2671 * If pinned groups are involved, flexible groups also need to be
2674 if (event_type & EVENT_PINNED)
2675 event_type |= EVENT_FLEXIBLE;
2677 ctx_event_type = event_type & EVENT_ALL;
2679 perf_pmu_disable(cpuctx->ctx.pmu);
2681 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2684 * Decide which cpu ctx groups to schedule out based on the types
2685 * of events that caused rescheduling:
2686 * - EVENT_CPU: schedule out corresponding groups;
2687 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2688 * - otherwise, do nothing more.
2691 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2692 else if (ctx_event_type & EVENT_PINNED)
2693 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2695 perf_event_sched_in(cpuctx, task_ctx, current);
2696 perf_pmu_enable(cpuctx->ctx.pmu);
2699 void perf_pmu_resched(struct pmu *pmu)
2701 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2702 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2704 perf_ctx_lock(cpuctx, task_ctx);
2705 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2706 perf_ctx_unlock(cpuctx, task_ctx);
2710 * Cross CPU call to install and enable a performance event
2712 * Very similar to remote_function() + event_function() but cannot assume that
2713 * things like ctx->is_active and cpuctx->task_ctx are set.
2715 static int __perf_install_in_context(void *info)
2717 struct perf_event *event = info;
2718 struct perf_event_context *ctx = event->ctx;
2719 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2720 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2721 bool reprogram = true;
2724 raw_spin_lock(&cpuctx->ctx.lock);
2726 raw_spin_lock(&ctx->lock);
2729 reprogram = (ctx->task == current);
2732 * If the task is running, it must be running on this CPU,
2733 * otherwise we cannot reprogram things.
2735 * If its not running, we don't care, ctx->lock will
2736 * serialize against it becoming runnable.
2738 if (task_curr(ctx->task) && !reprogram) {
2743 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2744 } else if (task_ctx) {
2745 raw_spin_lock(&task_ctx->lock);
2748 #ifdef CONFIG_CGROUP_PERF
2749 if (is_cgroup_event(event)) {
2751 * If the current cgroup doesn't match the event's
2752 * cgroup, we should not try to schedule it.
2754 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2755 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2756 event->cgrp->css.cgroup);
2761 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2762 add_event_to_ctx(event, ctx);
2763 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2765 add_event_to_ctx(event, ctx);
2769 perf_ctx_unlock(cpuctx, task_ctx);
2774 static bool exclusive_event_installable(struct perf_event *event,
2775 struct perf_event_context *ctx);
2778 * Attach a performance event to a context.
2780 * Very similar to event_function_call, see comment there.
2783 perf_install_in_context(struct perf_event_context *ctx,
2784 struct perf_event *event,
2787 struct task_struct *task = READ_ONCE(ctx->task);
2789 lockdep_assert_held(&ctx->mutex);
2791 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2793 if (event->cpu != -1)
2797 * Ensures that if we can observe event->ctx, both the event and ctx
2798 * will be 'complete'. See perf_iterate_sb_cpu().
2800 smp_store_release(&event->ctx, ctx);
2803 * perf_event_attr::disabled events will not run and can be initialized
2804 * without IPI. Except when this is the first event for the context, in
2805 * that case we need the magic of the IPI to set ctx->is_active.
2807 * The IOC_ENABLE that is sure to follow the creation of a disabled
2808 * event will issue the IPI and reprogram the hardware.
2810 if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF && ctx->nr_events) {
2811 raw_spin_lock_irq(&ctx->lock);
2812 if (ctx->task == TASK_TOMBSTONE) {
2813 raw_spin_unlock_irq(&ctx->lock);
2816 add_event_to_ctx(event, ctx);
2817 raw_spin_unlock_irq(&ctx->lock);
2822 cpu_function_call(cpu, __perf_install_in_context, event);
2827 * Should not happen, we validate the ctx is still alive before calling.
2829 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2833 * Installing events is tricky because we cannot rely on ctx->is_active
2834 * to be set in case this is the nr_events 0 -> 1 transition.
2836 * Instead we use task_curr(), which tells us if the task is running.
2837 * However, since we use task_curr() outside of rq::lock, we can race
2838 * against the actual state. This means the result can be wrong.
2840 * If we get a false positive, we retry, this is harmless.
2842 * If we get a false negative, things are complicated. If we are after
2843 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2844 * value must be correct. If we're before, it doesn't matter since
2845 * perf_event_context_sched_in() will program the counter.
2847 * However, this hinges on the remote context switch having observed
2848 * our task->perf_event_ctxp[] store, such that it will in fact take
2849 * ctx::lock in perf_event_context_sched_in().
2851 * We do this by task_function_call(), if the IPI fails to hit the task
2852 * we know any future context switch of task must see the
2853 * perf_event_ctpx[] store.
2857 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2858 * task_cpu() load, such that if the IPI then does not find the task
2859 * running, a future context switch of that task must observe the
2864 if (!task_function_call(task, __perf_install_in_context, event))
2867 raw_spin_lock_irq(&ctx->lock);
2869 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2871 * Cannot happen because we already checked above (which also
2872 * cannot happen), and we hold ctx->mutex, which serializes us
2873 * against perf_event_exit_task_context().
2875 raw_spin_unlock_irq(&ctx->lock);
2879 * If the task is not running, ctx->lock will avoid it becoming so,
2880 * thus we can safely install the event.
2882 if (task_curr(task)) {
2883 raw_spin_unlock_irq(&ctx->lock);
2886 add_event_to_ctx(event, ctx);
2887 raw_spin_unlock_irq(&ctx->lock);
2891 * Cross CPU call to enable a performance event
2893 static void __perf_event_enable(struct perf_event *event,
2894 struct perf_cpu_context *cpuctx,
2895 struct perf_event_context *ctx,
2898 struct perf_event *leader = event->group_leader;
2899 struct perf_event_context *task_ctx;
2901 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2902 event->state <= PERF_EVENT_STATE_ERROR)
2906 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2908 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2910 if (!ctx->is_active)
2913 if (!event_filter_match(event)) {
2914 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2919 * If the event is in a group and isn't the group leader,
2920 * then don't put it on unless the group is on.
2922 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2923 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2927 task_ctx = cpuctx->task_ctx;
2929 WARN_ON_ONCE(task_ctx != ctx);
2931 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2937 * If event->ctx is a cloned context, callers must make sure that
2938 * every task struct that event->ctx->task could possibly point to
2939 * remains valid. This condition is satisfied when called through
2940 * perf_event_for_each_child or perf_event_for_each as described
2941 * for perf_event_disable.
2943 static void _perf_event_enable(struct perf_event *event)
2945 struct perf_event_context *ctx = event->ctx;
2947 raw_spin_lock_irq(&ctx->lock);
2948 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2949 event->state < PERF_EVENT_STATE_ERROR) {
2950 raw_spin_unlock_irq(&ctx->lock);
2955 * If the event is in error state, clear that first.
2957 * That way, if we see the event in error state below, we know that it
2958 * has gone back into error state, as distinct from the task having
2959 * been scheduled away before the cross-call arrived.
2961 if (event->state == PERF_EVENT_STATE_ERROR)
2962 event->state = PERF_EVENT_STATE_OFF;
2963 raw_spin_unlock_irq(&ctx->lock);
2965 event_function_call(event, __perf_event_enable, NULL);
2969 * See perf_event_disable();
2971 void perf_event_enable(struct perf_event *event)
2973 struct perf_event_context *ctx;
2975 ctx = perf_event_ctx_lock(event);
2976 _perf_event_enable(event);
2977 perf_event_ctx_unlock(event, ctx);
2979 EXPORT_SYMBOL_GPL(perf_event_enable);
2981 struct stop_event_data {
2982 struct perf_event *event;
2983 unsigned int restart;
2986 static int __perf_event_stop(void *info)
2988 struct stop_event_data *sd = info;
2989 struct perf_event *event = sd->event;
2991 /* if it's already INACTIVE, do nothing */
2992 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2995 /* matches smp_wmb() in event_sched_in() */
2999 * There is a window with interrupts enabled before we get here,
3000 * so we need to check again lest we try to stop another CPU's event.
3002 if (READ_ONCE(event->oncpu) != smp_processor_id())
3005 event->pmu->stop(event, PERF_EF_UPDATE);
3008 * May race with the actual stop (through perf_pmu_output_stop()),
3009 * but it is only used for events with AUX ring buffer, and such
3010 * events will refuse to restart because of rb::aux_mmap_count==0,
3011 * see comments in perf_aux_output_begin().
3013 * Since this is happening on an event-local CPU, no trace is lost
3017 event->pmu->start(event, 0);
3022 static int perf_event_stop(struct perf_event *event, int restart)
3024 struct stop_event_data sd = {
3031 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3034 /* matches smp_wmb() in event_sched_in() */
3038 * We only want to restart ACTIVE events, so if the event goes
3039 * inactive here (event->oncpu==-1), there's nothing more to do;
3040 * fall through with ret==-ENXIO.
3042 ret = cpu_function_call(READ_ONCE(event->oncpu),
3043 __perf_event_stop, &sd);
3044 } while (ret == -EAGAIN);
3050 * In order to contain the amount of racy and tricky in the address filter
3051 * configuration management, it is a two part process:
3053 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
3054 * we update the addresses of corresponding vmas in
3055 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
3056 * (p2) when an event is scheduled in (pmu::add), it calls
3057 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
3058 * if the generation has changed since the previous call.
3060 * If (p1) happens while the event is active, we restart it to force (p2).
3062 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
3063 * pre-existing mappings, called once when new filters arrive via SET_FILTER
3065 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
3066 * registered mapping, called for every new mmap(), with mm::mmap_sem down
3068 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
3071 void perf_event_addr_filters_sync(struct perf_event *event)
3073 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
3075 if (!has_addr_filter(event))
3078 raw_spin_lock(&ifh->lock);
3079 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
3080 event->pmu->addr_filters_sync(event);
3081 event->hw.addr_filters_gen = event->addr_filters_gen;
3083 raw_spin_unlock(&ifh->lock);
3085 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
3087 static int _perf_event_refresh(struct perf_event *event, int refresh)
3090 * not supported on inherited events
3092 if (event->attr.inherit || !is_sampling_event(event))
3095 atomic_add(refresh, &event->event_limit);
3096 _perf_event_enable(event);
3102 * See perf_event_disable()
3104 int perf_event_refresh(struct perf_event *event, int refresh)
3106 struct perf_event_context *ctx;
3109 ctx = perf_event_ctx_lock(event);
3110 ret = _perf_event_refresh(event, refresh);
3111 perf_event_ctx_unlock(event, ctx);
3115 EXPORT_SYMBOL_GPL(perf_event_refresh);
3117 static int perf_event_modify_breakpoint(struct perf_event *bp,
3118 struct perf_event_attr *attr)
3122 _perf_event_disable(bp);
3124 err = modify_user_hw_breakpoint_check(bp, attr, true);
3126 if (!bp->attr.disabled)
3127 _perf_event_enable(bp);
3132 static int perf_event_modify_attr(struct perf_event *event,
3133 struct perf_event_attr *attr)
3135 if (event->attr.type != attr->type)
3138 switch (event->attr.type) {
3139 case PERF_TYPE_BREAKPOINT:
3140 return perf_event_modify_breakpoint(event, attr);
3142 /* Place holder for future additions. */
3147 static void ctx_sched_out(struct perf_event_context *ctx,
3148 struct perf_cpu_context *cpuctx,
3149 enum event_type_t event_type)
3151 struct perf_event *event, *tmp;
3152 int is_active = ctx->is_active;
3154 lockdep_assert_held(&ctx->lock);
3156 if (likely(!ctx->nr_events)) {
3158 * See __perf_remove_from_context().
3160 WARN_ON_ONCE(ctx->is_active);
3162 WARN_ON_ONCE(cpuctx->task_ctx);
3166 ctx->is_active &= ~event_type;
3167 if (!(ctx->is_active & EVENT_ALL))
3171 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3172 if (!ctx->is_active)
3173 cpuctx->task_ctx = NULL;
3177 * Always update time if it was set; not only when it changes.
3178 * Otherwise we can 'forget' to update time for any but the last
3179 * context we sched out. For example:
3181 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3182 * ctx_sched_out(.event_type = EVENT_PINNED)
3184 * would only update time for the pinned events.
3186 if (is_active & EVENT_TIME) {
3187 /* update (and stop) ctx time */
3188 update_context_time(ctx);
3189 update_cgrp_time_from_cpuctx(cpuctx);
3192 is_active ^= ctx->is_active; /* changed bits */
3194 if (!ctx->nr_active || !(is_active & EVENT_ALL))
3197 perf_pmu_disable(ctx->pmu);
3198 if (is_active & EVENT_PINNED) {
3199 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
3200 group_sched_out(event, cpuctx, ctx);
3203 if (is_active & EVENT_FLEXIBLE) {
3204 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
3205 group_sched_out(event, cpuctx, ctx);
3208 * Since we cleared EVENT_FLEXIBLE, also clear
3209 * rotate_necessary, is will be reset by
3210 * ctx_flexible_sched_in() when needed.
3212 ctx->rotate_necessary = 0;
3214 perf_pmu_enable(ctx->pmu);
3218 * Test whether two contexts are equivalent, i.e. whether they have both been
3219 * cloned from the same version of the same context.
3221 * Equivalence is measured using a generation number in the context that is
3222 * incremented on each modification to it; see unclone_ctx(), list_add_event()
3223 * and list_del_event().
3225 static int context_equiv(struct perf_event_context *ctx1,
3226 struct perf_event_context *ctx2)
3228 lockdep_assert_held(&ctx1->lock);
3229 lockdep_assert_held(&ctx2->lock);
3231 /* Pinning disables the swap optimization */
3232 if (ctx1->pin_count || ctx2->pin_count)
3235 /* If ctx1 is the parent of ctx2 */
3236 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3239 /* If ctx2 is the parent of ctx1 */
3240 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3244 * If ctx1 and ctx2 have the same parent; we flatten the parent
3245 * hierarchy, see perf_event_init_context().
3247 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3248 ctx1->parent_gen == ctx2->parent_gen)
3255 static void __perf_event_sync_stat(struct perf_event *event,
3256 struct perf_event *next_event)
3260 if (!event->attr.inherit_stat)
3264 * Update the event value, we cannot use perf_event_read()
3265 * because we're in the middle of a context switch and have IRQs
3266 * disabled, which upsets smp_call_function_single(), however
3267 * we know the event must be on the current CPU, therefore we
3268 * don't need to use it.
3270 if (event->state == PERF_EVENT_STATE_ACTIVE)
3271 event->pmu->read(event);
3273 perf_event_update_time(event);
3276 * In order to keep per-task stats reliable we need to flip the event
3277 * values when we flip the contexts.
3279 value = local64_read(&next_event->count);
3280 value = local64_xchg(&event->count, value);
3281 local64_set(&next_event->count, value);
3283 swap(event->total_time_enabled, next_event->total_time_enabled);
3284 swap(event->total_time_running, next_event->total_time_running);
3287 * Since we swizzled the values, update the user visible data too.
3289 perf_event_update_userpage(event);
3290 perf_event_update_userpage(next_event);
3293 static void perf_event_sync_stat(struct perf_event_context *ctx,
3294 struct perf_event_context *next_ctx)
3296 struct perf_event *event, *next_event;
3301 update_context_time(ctx);
3303 event = list_first_entry(&ctx->event_list,
3304 struct perf_event, event_entry);
3306 next_event = list_first_entry(&next_ctx->event_list,
3307 struct perf_event, event_entry);
3309 while (&event->event_entry != &ctx->event_list &&
3310 &next_event->event_entry != &next_ctx->event_list) {
3312 __perf_event_sync_stat(event, next_event);
3314 event = list_next_entry(event, event_entry);
3315 next_event = list_next_entry(next_event, event_entry);
3319 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3320 struct task_struct *next)
3322 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3323 struct perf_event_context *next_ctx;
3324 struct perf_event_context *parent, *next_parent;
3325 struct perf_cpu_context *cpuctx;
3331 cpuctx = __get_cpu_context(ctx);
3332 if (!cpuctx->task_ctx)
3336 next_ctx = next->perf_event_ctxp[ctxn];
3340 parent = rcu_dereference(ctx->parent_ctx);
3341 next_parent = rcu_dereference(next_ctx->parent_ctx);
3343 /* If neither context have a parent context; they cannot be clones. */
3344 if (!parent && !next_parent)
3347 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3349 * Looks like the two contexts are clones, so we might be
3350 * able to optimize the context switch. We lock both
3351 * contexts and check that they are clones under the
3352 * lock (including re-checking that neither has been
3353 * uncloned in the meantime). It doesn't matter which
3354 * order we take the locks because no other cpu could
3355 * be trying to lock both of these tasks.
3357 raw_spin_lock(&ctx->lock);
3358 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3359 if (context_equiv(ctx, next_ctx)) {
3360 struct pmu *pmu = ctx->pmu;
3362 WRITE_ONCE(ctx->task, next);
3363 WRITE_ONCE(next_ctx->task, task);
3366 * PMU specific parts of task perf context can require
3367 * additional synchronization. As an example of such
3368 * synchronization see implementation details of Intel
3369 * LBR call stack data profiling;
3371 if (pmu->swap_task_ctx)
3372 pmu->swap_task_ctx(ctx, next_ctx);
3374 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3377 * RCU_INIT_POINTER here is safe because we've not
3378 * modified the ctx and the above modification of
3379 * ctx->task and ctx->task_ctx_data are immaterial
3380 * since those values are always verified under
3381 * ctx->lock which we're now holding.
3383 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3384 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3388 perf_event_sync_stat(ctx, next_ctx);
3390 raw_spin_unlock(&next_ctx->lock);
3391 raw_spin_unlock(&ctx->lock);
3397 raw_spin_lock(&ctx->lock);
3398 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3399 raw_spin_unlock(&ctx->lock);
3403 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3405 void perf_sched_cb_dec(struct pmu *pmu)
3407 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3409 this_cpu_dec(perf_sched_cb_usages);
3411 if (!--cpuctx->sched_cb_usage)
3412 list_del(&cpuctx->sched_cb_entry);
3416 void perf_sched_cb_inc(struct pmu *pmu)
3418 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3420 if (!cpuctx->sched_cb_usage++)
3421 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3423 this_cpu_inc(perf_sched_cb_usages);
3427 * This function provides the context switch callback to the lower code
3428 * layer. It is invoked ONLY when the context switch callback is enabled.
3430 * This callback is relevant even to per-cpu events; for example multi event
3431 * PEBS requires this to provide PID/TID information. This requires we flush
3432 * all queued PEBS records before we context switch to a new task.
3434 static void perf_pmu_sched_task(struct task_struct *prev,
3435 struct task_struct *next,
3438 struct perf_cpu_context *cpuctx;
3444 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3445 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3447 if (WARN_ON_ONCE(!pmu->sched_task))
3450 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3451 perf_pmu_disable(pmu);
3453 pmu->sched_task(cpuctx->task_ctx, sched_in);
3455 perf_pmu_enable(pmu);
3456 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3460 static void perf_event_switch(struct task_struct *task,
3461 struct task_struct *next_prev, bool sched_in);
3463 #define for_each_task_context_nr(ctxn) \
3464 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3467 * Called from scheduler to remove the events of the current task,
3468 * with interrupts disabled.
3470 * We stop each event and update the event value in event->count.
3472 * This does not protect us against NMI, but disable()
3473 * sets the disabled bit in the control field of event _before_
3474 * accessing the event control register. If a NMI hits, then it will
3475 * not restart the event.
3477 void __perf_event_task_sched_out(struct task_struct *task,
3478 struct task_struct *next)
3482 if (__this_cpu_read(perf_sched_cb_usages))
3483 perf_pmu_sched_task(task, next, false);
3485 if (atomic_read(&nr_switch_events))
3486 perf_event_switch(task, next, false);
3488 for_each_task_context_nr(ctxn)
3489 perf_event_context_sched_out(task, ctxn, next);
3492 * if cgroup events exist on this CPU, then we need
3493 * to check if we have to switch out PMU state.
3494 * cgroup event are system-wide mode only
3496 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3497 perf_cgroup_sched_out(task, next);
3501 * Called with IRQs disabled
3503 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3504 enum event_type_t event_type)
3506 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3509 static bool perf_less_group_idx(const void *l, const void *r)
3511 const struct perf_event *le = l, *re = r;
3513 return le->group_index < re->group_index;
3516 static void swap_ptr(void *l, void *r)
3518 void **lp = l, **rp = r;
3523 static const struct min_heap_callbacks perf_min_heap = {
3524 .elem_size = sizeof(struct perf_event *),
3525 .less = perf_less_group_idx,
3529 static void __heap_add(struct min_heap *heap, struct perf_event *event)
3531 struct perf_event **itrs = heap->data;
3534 itrs[heap->nr] = event;
3539 static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx,
3540 struct perf_event_groups *groups, int cpu,
3541 int (*func)(struct perf_event *, void *),
3544 #ifdef CONFIG_CGROUP_PERF
3545 struct cgroup_subsys_state *css = NULL;
3547 /* Space for per CPU and/or any CPU event iterators. */
3548 struct perf_event *itrs[2];
3549 struct min_heap event_heap;
3550 struct perf_event **evt;
3554 event_heap = (struct min_heap){
3555 .data = cpuctx->heap,
3557 .size = cpuctx->heap_size,
3560 lockdep_assert_held(&cpuctx->ctx.lock);
3562 #ifdef CONFIG_CGROUP_PERF
3564 css = &cpuctx->cgrp->css;
3567 event_heap = (struct min_heap){
3570 .size = ARRAY_SIZE(itrs),
3572 /* Events not within a CPU context may be on any CPU. */
3573 __heap_add(&event_heap, perf_event_groups_first(groups, -1, NULL));
3575 evt = event_heap.data;
3577 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, NULL));
3579 #ifdef CONFIG_CGROUP_PERF
3580 for (; css; css = css->parent)
3581 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, css->cgroup));
3584 min_heapify_all(&event_heap, &perf_min_heap);
3586 while (event_heap.nr) {
3587 ret = func(*evt, data);
3591 *evt = perf_event_groups_next(*evt);
3593 min_heapify(&event_heap, 0, &perf_min_heap);
3595 min_heap_pop(&event_heap, &perf_min_heap);
3601 static int merge_sched_in(struct perf_event *event, void *data)
3603 struct perf_event_context *ctx = event->ctx;
3604 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3605 int *can_add_hw = data;
3607 if (event->state <= PERF_EVENT_STATE_OFF)
3610 if (!event_filter_match(event))
3613 if (group_can_go_on(event, cpuctx, *can_add_hw)) {
3614 if (!group_sched_in(event, cpuctx, ctx))
3615 list_add_tail(&event->active_list, get_event_list(event));
3618 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3619 if (event->attr.pinned)
3620 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3623 ctx->rotate_necessary = 1;
3630 ctx_pinned_sched_in(struct perf_event_context *ctx,
3631 struct perf_cpu_context *cpuctx)
3635 if (ctx != &cpuctx->ctx)
3638 visit_groups_merge(cpuctx, &ctx->pinned_groups,
3640 merge_sched_in, &can_add_hw);
3644 ctx_flexible_sched_in(struct perf_event_context *ctx,
3645 struct perf_cpu_context *cpuctx)
3649 if (ctx != &cpuctx->ctx)
3652 visit_groups_merge(cpuctx, &ctx->flexible_groups,
3654 merge_sched_in, &can_add_hw);
3658 ctx_sched_in(struct perf_event_context *ctx,
3659 struct perf_cpu_context *cpuctx,
3660 enum event_type_t event_type,
3661 struct task_struct *task)
3663 int is_active = ctx->is_active;
3666 lockdep_assert_held(&ctx->lock);
3668 if (likely(!ctx->nr_events))
3671 ctx->is_active |= (event_type | EVENT_TIME);
3674 cpuctx->task_ctx = ctx;
3676 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3679 is_active ^= ctx->is_active; /* changed bits */
3681 if (is_active & EVENT_TIME) {
3682 /* start ctx time */
3684 ctx->timestamp = now;
3685 perf_cgroup_set_timestamp(task, ctx);
3689 * First go through the list and put on any pinned groups
3690 * in order to give them the best chance of going on.
3692 if (is_active & EVENT_PINNED)
3693 ctx_pinned_sched_in(ctx, cpuctx);
3695 /* Then walk through the lower prio flexible groups */
3696 if (is_active & EVENT_FLEXIBLE)
3697 ctx_flexible_sched_in(ctx, cpuctx);
3700 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3701 enum event_type_t event_type,
3702 struct task_struct *task)
3704 struct perf_event_context *ctx = &cpuctx->ctx;
3706 ctx_sched_in(ctx, cpuctx, event_type, task);
3709 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3710 struct task_struct *task)
3712 struct perf_cpu_context *cpuctx;
3714 cpuctx = __get_cpu_context(ctx);
3715 if (cpuctx->task_ctx == ctx)
3718 perf_ctx_lock(cpuctx, ctx);
3720 * We must check ctx->nr_events while holding ctx->lock, such
3721 * that we serialize against perf_install_in_context().
3723 if (!ctx->nr_events)
3726 perf_pmu_disable(ctx->pmu);
3728 * We want to keep the following priority order:
3729 * cpu pinned (that don't need to move), task pinned,
3730 * cpu flexible, task flexible.
3732 * However, if task's ctx is not carrying any pinned
3733 * events, no need to flip the cpuctx's events around.
3735 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3736 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3737 perf_event_sched_in(cpuctx, ctx, task);
3738 perf_pmu_enable(ctx->pmu);
3741 perf_ctx_unlock(cpuctx, ctx);
3745 * Called from scheduler to add the events of the current task
3746 * with interrupts disabled.
3748 * We restore the event value and then enable it.
3750 * This does not protect us against NMI, but enable()
3751 * sets the enabled bit in the control field of event _before_
3752 * accessing the event control register. If a NMI hits, then it will
3753 * keep the event running.
3755 void __perf_event_task_sched_in(struct task_struct *prev,
3756 struct task_struct *task)
3758 struct perf_event_context *ctx;
3762 * If cgroup events exist on this CPU, then we need to check if we have
3763 * to switch in PMU state; cgroup event are system-wide mode only.
3765 * Since cgroup events are CPU events, we must schedule these in before
3766 * we schedule in the task events.
3768 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3769 perf_cgroup_sched_in(prev, task);
3771 for_each_task_context_nr(ctxn) {
3772 ctx = task->perf_event_ctxp[ctxn];
3776 perf_event_context_sched_in(ctx, task);
3779 if (atomic_read(&nr_switch_events))
3780 perf_event_switch(task, prev, true);
3782 if (__this_cpu_read(perf_sched_cb_usages))
3783 perf_pmu_sched_task(prev, task, true);
3786 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3788 u64 frequency = event->attr.sample_freq;
3789 u64 sec = NSEC_PER_SEC;
3790 u64 divisor, dividend;
3792 int count_fls, nsec_fls, frequency_fls, sec_fls;
3794 count_fls = fls64(count);
3795 nsec_fls = fls64(nsec);
3796 frequency_fls = fls64(frequency);
3800 * We got @count in @nsec, with a target of sample_freq HZ
3801 * the target period becomes:
3804 * period = -------------------
3805 * @nsec * sample_freq
3810 * Reduce accuracy by one bit such that @a and @b converge
3811 * to a similar magnitude.
3813 #define REDUCE_FLS(a, b) \
3815 if (a##_fls > b##_fls) { \
3825 * Reduce accuracy until either term fits in a u64, then proceed with
3826 * the other, so that finally we can do a u64/u64 division.
3828 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3829 REDUCE_FLS(nsec, frequency);
3830 REDUCE_FLS(sec, count);
3833 if (count_fls + sec_fls > 64) {
3834 divisor = nsec * frequency;
3836 while (count_fls + sec_fls > 64) {
3837 REDUCE_FLS(count, sec);
3841 dividend = count * sec;
3843 dividend = count * sec;
3845 while (nsec_fls + frequency_fls > 64) {
3846 REDUCE_FLS(nsec, frequency);
3850 divisor = nsec * frequency;
3856 return div64_u64(dividend, divisor);
3859 static DEFINE_PER_CPU(int, perf_throttled_count);
3860 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3862 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3864 struct hw_perf_event *hwc = &event->hw;
3865 s64 period, sample_period;
3868 period = perf_calculate_period(event, nsec, count);
3870 delta = (s64)(period - hwc->sample_period);
3871 delta = (delta + 7) / 8; /* low pass filter */
3873 sample_period = hwc->sample_period + delta;
3878 hwc->sample_period = sample_period;
3880 if (local64_read(&hwc->period_left) > 8*sample_period) {
3882 event->pmu->stop(event, PERF_EF_UPDATE);
3884 local64_set(&hwc->period_left, 0);
3887 event->pmu->start(event, PERF_EF_RELOAD);
3892 * combine freq adjustment with unthrottling to avoid two passes over the
3893 * events. At the same time, make sure, having freq events does not change
3894 * the rate of unthrottling as that would introduce bias.
3896 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3899 struct perf_event *event;
3900 struct hw_perf_event *hwc;
3901 u64 now, period = TICK_NSEC;
3905 * only need to iterate over all events iff:
3906 * - context have events in frequency mode (needs freq adjust)
3907 * - there are events to unthrottle on this cpu
3909 if (!(ctx->nr_freq || needs_unthr))
3912 raw_spin_lock(&ctx->lock);
3913 perf_pmu_disable(ctx->pmu);
3915 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3916 if (event->state != PERF_EVENT_STATE_ACTIVE)
3919 if (!event_filter_match(event))
3922 perf_pmu_disable(event->pmu);
3926 if (hwc->interrupts == MAX_INTERRUPTS) {
3927 hwc->interrupts = 0;
3928 perf_log_throttle(event, 1);
3929 event->pmu->start(event, 0);
3932 if (!event->attr.freq || !event->attr.sample_freq)
3936 * stop the event and update event->count
3938 event->pmu->stop(event, PERF_EF_UPDATE);
3940 now = local64_read(&event->count);
3941 delta = now - hwc->freq_count_stamp;
3942 hwc->freq_count_stamp = now;
3946 * reload only if value has changed
3947 * we have stopped the event so tell that
3948 * to perf_adjust_period() to avoid stopping it
3952 perf_adjust_period(event, period, delta, false);
3954 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3956 perf_pmu_enable(event->pmu);
3959 perf_pmu_enable(ctx->pmu);
3960 raw_spin_unlock(&ctx->lock);
3964 * Move @event to the tail of the @ctx's elegible events.
3966 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
3969 * Rotate the first entry last of non-pinned groups. Rotation might be
3970 * disabled by the inheritance code.
3972 if (ctx->rotate_disable)
3975 perf_event_groups_delete(&ctx->flexible_groups, event);
3976 perf_event_groups_insert(&ctx->flexible_groups, event);
3979 /* pick an event from the flexible_groups to rotate */
3980 static inline struct perf_event *
3981 ctx_event_to_rotate(struct perf_event_context *ctx)
3983 struct perf_event *event;
3985 /* pick the first active flexible event */
3986 event = list_first_entry_or_null(&ctx->flexible_active,
3987 struct perf_event, active_list);
3989 /* if no active flexible event, pick the first event */
3991 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
3992 typeof(*event), group_node);
3996 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
3997 * finds there are unschedulable events, it will set it again.
3999 ctx->rotate_necessary = 0;
4004 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
4006 struct perf_event *cpu_event = NULL, *task_event = NULL;
4007 struct perf_event_context *task_ctx = NULL;
4008 int cpu_rotate, task_rotate;
4011 * Since we run this from IRQ context, nobody can install new
4012 * events, thus the event count values are stable.
4015 cpu_rotate = cpuctx->ctx.rotate_necessary;
4016 task_ctx = cpuctx->task_ctx;
4017 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
4019 if (!(cpu_rotate || task_rotate))
4022 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
4023 perf_pmu_disable(cpuctx->ctx.pmu);
4026 task_event = ctx_event_to_rotate(task_ctx);
4028 cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
4031 * As per the order given at ctx_resched() first 'pop' task flexible
4032 * and then, if needed CPU flexible.
4034 if (task_event || (task_ctx && cpu_event))
4035 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
4037 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
4040 rotate_ctx(task_ctx, task_event);
4042 rotate_ctx(&cpuctx->ctx, cpu_event);
4044 perf_event_sched_in(cpuctx, task_ctx, current);
4046 perf_pmu_enable(cpuctx->ctx.pmu);
4047 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
4052 void perf_event_task_tick(void)
4054 struct list_head *head = this_cpu_ptr(&active_ctx_list);
4055 struct perf_event_context *ctx, *tmp;
4058 lockdep_assert_irqs_disabled();
4060 __this_cpu_inc(perf_throttled_seq);
4061 throttled = __this_cpu_xchg(perf_throttled_count, 0);
4062 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
4064 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
4065 perf_adjust_freq_unthr_context(ctx, throttled);
4068 static int event_enable_on_exec(struct perf_event *event,
4069 struct perf_event_context *ctx)
4071 if (!event->attr.enable_on_exec)
4074 event->attr.enable_on_exec = 0;
4075 if (event->state >= PERF_EVENT_STATE_INACTIVE)
4078 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
4084 * Enable all of a task's events that have been marked enable-on-exec.
4085 * This expects task == current.
4087 static void perf_event_enable_on_exec(int ctxn)
4089 struct perf_event_context *ctx, *clone_ctx = NULL;
4090 enum event_type_t event_type = 0;
4091 struct perf_cpu_context *cpuctx;
4092 struct perf_event *event;
4093 unsigned long flags;
4096 local_irq_save(flags);
4097 ctx = current->perf_event_ctxp[ctxn];
4098 if (!ctx || !ctx->nr_events)
4101 cpuctx = __get_cpu_context(ctx);
4102 perf_ctx_lock(cpuctx, ctx);
4103 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
4104 list_for_each_entry(event, &ctx->event_list, event_entry) {
4105 enabled |= event_enable_on_exec(event, ctx);
4106 event_type |= get_event_type(event);
4110 * Unclone and reschedule this context if we enabled any event.
4113 clone_ctx = unclone_ctx(ctx);
4114 ctx_resched(cpuctx, ctx, event_type);
4116 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
4118 perf_ctx_unlock(cpuctx, ctx);
4121 local_irq_restore(flags);
4127 struct perf_read_data {
4128 struct perf_event *event;
4133 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
4135 u16 local_pkg, event_pkg;
4137 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
4138 int local_cpu = smp_processor_id();
4140 event_pkg = topology_physical_package_id(event_cpu);
4141 local_pkg = topology_physical_package_id(local_cpu);
4143 if (event_pkg == local_pkg)
4151 * Cross CPU call to read the hardware event
4153 static void __perf_event_read(void *info)
4155 struct perf_read_data *data = info;
4156 struct perf_event *sub, *event = data->event;
4157 struct perf_event_context *ctx = event->ctx;
4158 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
4159 struct pmu *pmu = event->pmu;
4162 * If this is a task context, we need to check whether it is
4163 * the current task context of this cpu. If not it has been
4164 * scheduled out before the smp call arrived. In that case
4165 * event->count would have been updated to a recent sample
4166 * when the event was scheduled out.
4168 if (ctx->task && cpuctx->task_ctx != ctx)
4171 raw_spin_lock(&ctx->lock);
4172 if (ctx->is_active & EVENT_TIME) {
4173 update_context_time(ctx);
4174 update_cgrp_time_from_event(event);
4177 perf_event_update_time(event);
4179 perf_event_update_sibling_time(event);
4181 if (event->state != PERF_EVENT_STATE_ACTIVE)
4190 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
4194 for_each_sibling_event(sub, event) {
4195 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
4197 * Use sibling's PMU rather than @event's since
4198 * sibling could be on different (eg: software) PMU.
4200 sub->pmu->read(sub);
4204 data->ret = pmu->commit_txn(pmu);
4207 raw_spin_unlock(&ctx->lock);
4210 static inline u64 perf_event_count(struct perf_event *event)
4212 return local64_read(&event->count) + atomic64_read(&event->child_count);
4216 * NMI-safe method to read a local event, that is an event that
4218 * - either for the current task, or for this CPU
4219 * - does not have inherit set, for inherited task events
4220 * will not be local and we cannot read them atomically
4221 * - must not have a pmu::count method
4223 int perf_event_read_local(struct perf_event *event, u64 *value,
4224 u64 *enabled, u64 *running)
4226 unsigned long flags;
4230 * Disabling interrupts avoids all counter scheduling (context
4231 * switches, timer based rotation and IPIs).
4233 local_irq_save(flags);
4236 * It must not be an event with inherit set, we cannot read
4237 * all child counters from atomic context.
4239 if (event->attr.inherit) {
4244 /* If this is a per-task event, it must be for current */
4245 if ((event->attach_state & PERF_ATTACH_TASK) &&
4246 event->hw.target != current) {
4251 /* If this is a per-CPU event, it must be for this CPU */
4252 if (!(event->attach_state & PERF_ATTACH_TASK) &&
4253 event->cpu != smp_processor_id()) {
4258 /* If this is a pinned event it must be running on this CPU */
4259 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4265 * If the event is currently on this CPU, its either a per-task event,
4266 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4269 if (event->oncpu == smp_processor_id())
4270 event->pmu->read(event);
4272 *value = local64_read(&event->count);
4273 if (enabled || running) {
4274 u64 now = event->shadow_ctx_time + perf_clock();
4275 u64 __enabled, __running;
4277 __perf_update_times(event, now, &__enabled, &__running);
4279 *enabled = __enabled;
4281 *running = __running;
4284 local_irq_restore(flags);
4289 static int perf_event_read(struct perf_event *event, bool group)
4291 enum perf_event_state state = READ_ONCE(event->state);
4292 int event_cpu, ret = 0;
4295 * If event is enabled and currently active on a CPU, update the
4296 * value in the event structure:
4299 if (state == PERF_EVENT_STATE_ACTIVE) {
4300 struct perf_read_data data;
4303 * Orders the ->state and ->oncpu loads such that if we see
4304 * ACTIVE we must also see the right ->oncpu.
4306 * Matches the smp_wmb() from event_sched_in().
4310 event_cpu = READ_ONCE(event->oncpu);
4311 if ((unsigned)event_cpu >= nr_cpu_ids)
4314 data = (struct perf_read_data){
4321 event_cpu = __perf_event_read_cpu(event, event_cpu);
4324 * Purposely ignore the smp_call_function_single() return
4327 * If event_cpu isn't a valid CPU it means the event got
4328 * scheduled out and that will have updated the event count.
4330 * Therefore, either way, we'll have an up-to-date event count
4333 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4337 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4338 struct perf_event_context *ctx = event->ctx;
4339 unsigned long flags;
4341 raw_spin_lock_irqsave(&ctx->lock, flags);
4342 state = event->state;
4343 if (state != PERF_EVENT_STATE_INACTIVE) {
4344 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4349 * May read while context is not active (e.g., thread is
4350 * blocked), in that case we cannot update context time
4352 if (ctx->is_active & EVENT_TIME) {
4353 update_context_time(ctx);
4354 update_cgrp_time_from_event(event);
4357 perf_event_update_time(event);
4359 perf_event_update_sibling_time(event);
4360 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4367 * Initialize the perf_event context in a task_struct:
4369 static void __perf_event_init_context(struct perf_event_context *ctx)
4371 raw_spin_lock_init(&ctx->lock);
4372 mutex_init(&ctx->mutex);
4373 INIT_LIST_HEAD(&ctx->active_ctx_list);
4374 perf_event_groups_init(&ctx->pinned_groups);
4375 perf_event_groups_init(&ctx->flexible_groups);
4376 INIT_LIST_HEAD(&ctx->event_list);
4377 INIT_LIST_HEAD(&ctx->pinned_active);
4378 INIT_LIST_HEAD(&ctx->flexible_active);
4379 refcount_set(&ctx->refcount, 1);
4382 static struct perf_event_context *
4383 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4385 struct perf_event_context *ctx;
4387 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4391 __perf_event_init_context(ctx);
4393 ctx->task = get_task_struct(task);
4399 static struct task_struct *
4400 find_lively_task_by_vpid(pid_t vpid)
4402 struct task_struct *task;
4408 task = find_task_by_vpid(vpid);
4410 get_task_struct(task);
4414 return ERR_PTR(-ESRCH);
4420 * Returns a matching context with refcount and pincount.
4422 static struct perf_event_context *
4423 find_get_context(struct pmu *pmu, struct task_struct *task,
4424 struct perf_event *event)
4426 struct perf_event_context *ctx, *clone_ctx = NULL;
4427 struct perf_cpu_context *cpuctx;
4428 void *task_ctx_data = NULL;
4429 unsigned long flags;
4431 int cpu = event->cpu;
4434 /* Must be root to operate on a CPU event: */
4435 err = perf_allow_cpu(&event->attr);
4437 return ERR_PTR(err);
4439 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4448 ctxn = pmu->task_ctx_nr;
4452 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4453 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4454 if (!task_ctx_data) {
4461 ctx = perf_lock_task_context(task, ctxn, &flags);
4463 clone_ctx = unclone_ctx(ctx);
4466 if (task_ctx_data && !ctx->task_ctx_data) {
4467 ctx->task_ctx_data = task_ctx_data;
4468 task_ctx_data = NULL;
4470 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4475 ctx = alloc_perf_context(pmu, task);
4480 if (task_ctx_data) {
4481 ctx->task_ctx_data = task_ctx_data;
4482 task_ctx_data = NULL;
4486 mutex_lock(&task->perf_event_mutex);
4488 * If it has already passed perf_event_exit_task().
4489 * we must see PF_EXITING, it takes this mutex too.
4491 if (task->flags & PF_EXITING)
4493 else if (task->perf_event_ctxp[ctxn])
4498 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4500 mutex_unlock(&task->perf_event_mutex);
4502 if (unlikely(err)) {
4511 kfree(task_ctx_data);
4515 kfree(task_ctx_data);
4516 return ERR_PTR(err);
4519 static void perf_event_free_filter(struct perf_event *event);
4520 static void perf_event_free_bpf_prog(struct perf_event *event);
4522 static void free_event_rcu(struct rcu_head *head)
4524 struct perf_event *event;
4526 event = container_of(head, struct perf_event, rcu_head);
4528 put_pid_ns(event->ns);
4529 perf_event_free_filter(event);
4533 static void ring_buffer_attach(struct perf_event *event,
4534 struct perf_buffer *rb);
4536 static void detach_sb_event(struct perf_event *event)
4538 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4540 raw_spin_lock(&pel->lock);
4541 list_del_rcu(&event->sb_list);
4542 raw_spin_unlock(&pel->lock);
4545 static bool is_sb_event(struct perf_event *event)
4547 struct perf_event_attr *attr = &event->attr;
4552 if (event->attach_state & PERF_ATTACH_TASK)
4555 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4556 attr->comm || attr->comm_exec ||
4557 attr->task || attr->ksymbol ||
4558 attr->context_switch ||
4564 static void unaccount_pmu_sb_event(struct perf_event *event)
4566 if (is_sb_event(event))
4567 detach_sb_event(event);
4570 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4575 if (is_cgroup_event(event))
4576 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4579 #ifdef CONFIG_NO_HZ_FULL
4580 static DEFINE_SPINLOCK(nr_freq_lock);
4583 static void unaccount_freq_event_nohz(void)
4585 #ifdef CONFIG_NO_HZ_FULL
4586 spin_lock(&nr_freq_lock);
4587 if (atomic_dec_and_test(&nr_freq_events))
4588 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4589 spin_unlock(&nr_freq_lock);
4593 static void unaccount_freq_event(void)
4595 if (tick_nohz_full_enabled())
4596 unaccount_freq_event_nohz();
4598 atomic_dec(&nr_freq_events);
4601 static void unaccount_event(struct perf_event *event)
4608 if (event->attach_state & PERF_ATTACH_TASK)
4610 if (event->attr.mmap || event->attr.mmap_data)
4611 atomic_dec(&nr_mmap_events);
4612 if (event->attr.comm)
4613 atomic_dec(&nr_comm_events);
4614 if (event->attr.namespaces)
4615 atomic_dec(&nr_namespaces_events);
4616 if (event->attr.cgroup)
4617 atomic_dec(&nr_cgroup_events);
4618 if (event->attr.task)
4619 atomic_dec(&nr_task_events);
4620 if (event->attr.freq)
4621 unaccount_freq_event();
4622 if (event->attr.context_switch) {
4624 atomic_dec(&nr_switch_events);
4626 if (is_cgroup_event(event))
4628 if (has_branch_stack(event))
4630 if (event->attr.ksymbol)
4631 atomic_dec(&nr_ksymbol_events);
4632 if (event->attr.bpf_event)
4633 atomic_dec(&nr_bpf_events);
4636 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4637 schedule_delayed_work(&perf_sched_work, HZ);
4640 unaccount_event_cpu(event, event->cpu);
4642 unaccount_pmu_sb_event(event);
4645 static void perf_sched_delayed(struct work_struct *work)
4647 mutex_lock(&perf_sched_mutex);
4648 if (atomic_dec_and_test(&perf_sched_count))
4649 static_branch_disable(&perf_sched_events);
4650 mutex_unlock(&perf_sched_mutex);
4654 * The following implement mutual exclusion of events on "exclusive" pmus
4655 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4656 * at a time, so we disallow creating events that might conflict, namely:
4658 * 1) cpu-wide events in the presence of per-task events,
4659 * 2) per-task events in the presence of cpu-wide events,
4660 * 3) two matching events on the same context.
4662 * The former two cases are handled in the allocation path (perf_event_alloc(),
4663 * _free_event()), the latter -- before the first perf_install_in_context().
4665 static int exclusive_event_init(struct perf_event *event)
4667 struct pmu *pmu = event->pmu;
4669 if (!is_exclusive_pmu(pmu))
4673 * Prevent co-existence of per-task and cpu-wide events on the
4674 * same exclusive pmu.
4676 * Negative pmu::exclusive_cnt means there are cpu-wide
4677 * events on this "exclusive" pmu, positive means there are
4680 * Since this is called in perf_event_alloc() path, event::ctx
4681 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4682 * to mean "per-task event", because unlike other attach states it
4683 * never gets cleared.
4685 if (event->attach_state & PERF_ATTACH_TASK) {
4686 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4689 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4696 static void exclusive_event_destroy(struct perf_event *event)
4698 struct pmu *pmu = event->pmu;
4700 if (!is_exclusive_pmu(pmu))
4703 /* see comment in exclusive_event_init() */
4704 if (event->attach_state & PERF_ATTACH_TASK)
4705 atomic_dec(&pmu->exclusive_cnt);
4707 atomic_inc(&pmu->exclusive_cnt);
4710 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4712 if ((e1->pmu == e2->pmu) &&
4713 (e1->cpu == e2->cpu ||
4720 static bool exclusive_event_installable(struct perf_event *event,
4721 struct perf_event_context *ctx)
4723 struct perf_event *iter_event;
4724 struct pmu *pmu = event->pmu;
4726 lockdep_assert_held(&ctx->mutex);
4728 if (!is_exclusive_pmu(pmu))
4731 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4732 if (exclusive_event_match(iter_event, event))
4739 static void perf_addr_filters_splice(struct perf_event *event,
4740 struct list_head *head);
4742 static void _free_event(struct perf_event *event)
4744 irq_work_sync(&event->pending);
4746 unaccount_event(event);
4748 security_perf_event_free(event);
4752 * Can happen when we close an event with re-directed output.
4754 * Since we have a 0 refcount, perf_mmap_close() will skip
4755 * over us; possibly making our ring_buffer_put() the last.
4757 mutex_lock(&event->mmap_mutex);
4758 ring_buffer_attach(event, NULL);
4759 mutex_unlock(&event->mmap_mutex);
4762 if (is_cgroup_event(event))
4763 perf_detach_cgroup(event);
4765 if (!event->parent) {
4766 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4767 put_callchain_buffers();
4770 perf_event_free_bpf_prog(event);
4771 perf_addr_filters_splice(event, NULL);
4772 kfree(event->addr_filter_ranges);
4775 event->destroy(event);
4778 * Must be after ->destroy(), due to uprobe_perf_close() using
4781 if (event->hw.target)
4782 put_task_struct(event->hw.target);
4785 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4786 * all task references must be cleaned up.
4789 put_ctx(event->ctx);
4791 exclusive_event_destroy(event);
4792 module_put(event->pmu->module);
4794 call_rcu(&event->rcu_head, free_event_rcu);
4798 * Used to free events which have a known refcount of 1, such as in error paths
4799 * where the event isn't exposed yet and inherited events.
4801 static void free_event(struct perf_event *event)
4803 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4804 "unexpected event refcount: %ld; ptr=%p\n",
4805 atomic_long_read(&event->refcount), event)) {
4806 /* leak to avoid use-after-free */
4814 * Remove user event from the owner task.
4816 static void perf_remove_from_owner(struct perf_event *event)
4818 struct task_struct *owner;
4822 * Matches the smp_store_release() in perf_event_exit_task(). If we
4823 * observe !owner it means the list deletion is complete and we can
4824 * indeed free this event, otherwise we need to serialize on
4825 * owner->perf_event_mutex.
4827 owner = READ_ONCE(event->owner);
4830 * Since delayed_put_task_struct() also drops the last
4831 * task reference we can safely take a new reference
4832 * while holding the rcu_read_lock().
4834 get_task_struct(owner);
4840 * If we're here through perf_event_exit_task() we're already
4841 * holding ctx->mutex which would be an inversion wrt. the
4842 * normal lock order.
4844 * However we can safely take this lock because its the child
4847 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4850 * We have to re-check the event->owner field, if it is cleared
4851 * we raced with perf_event_exit_task(), acquiring the mutex
4852 * ensured they're done, and we can proceed with freeing the
4856 list_del_init(&event->owner_entry);
4857 smp_store_release(&event->owner, NULL);
4859 mutex_unlock(&owner->perf_event_mutex);
4860 put_task_struct(owner);
4864 static void put_event(struct perf_event *event)
4866 if (!atomic_long_dec_and_test(&event->refcount))
4873 * Kill an event dead; while event:refcount will preserve the event
4874 * object, it will not preserve its functionality. Once the last 'user'
4875 * gives up the object, we'll destroy the thing.
4877 int perf_event_release_kernel(struct perf_event *event)
4879 struct perf_event_context *ctx = event->ctx;
4880 struct perf_event *child, *tmp;
4881 LIST_HEAD(free_list);
4884 * If we got here through err_file: fput(event_file); we will not have
4885 * attached to a context yet.
4888 WARN_ON_ONCE(event->attach_state &
4889 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4893 if (!is_kernel_event(event))
4894 perf_remove_from_owner(event);
4896 ctx = perf_event_ctx_lock(event);
4897 WARN_ON_ONCE(ctx->parent_ctx);
4898 perf_remove_from_context(event, DETACH_GROUP);
4900 raw_spin_lock_irq(&ctx->lock);
4902 * Mark this event as STATE_DEAD, there is no external reference to it
4905 * Anybody acquiring event->child_mutex after the below loop _must_
4906 * also see this, most importantly inherit_event() which will avoid
4907 * placing more children on the list.
4909 * Thus this guarantees that we will in fact observe and kill _ALL_
4912 event->state = PERF_EVENT_STATE_DEAD;
4913 raw_spin_unlock_irq(&ctx->lock);
4915 perf_event_ctx_unlock(event, ctx);
4918 mutex_lock(&event->child_mutex);
4919 list_for_each_entry(child, &event->child_list, child_list) {
4922 * Cannot change, child events are not migrated, see the
4923 * comment with perf_event_ctx_lock_nested().
4925 ctx = READ_ONCE(child->ctx);
4927 * Since child_mutex nests inside ctx::mutex, we must jump
4928 * through hoops. We start by grabbing a reference on the ctx.
4930 * Since the event cannot get freed while we hold the
4931 * child_mutex, the context must also exist and have a !0
4937 * Now that we have a ctx ref, we can drop child_mutex, and
4938 * acquire ctx::mutex without fear of it going away. Then we
4939 * can re-acquire child_mutex.
4941 mutex_unlock(&event->child_mutex);
4942 mutex_lock(&ctx->mutex);
4943 mutex_lock(&event->child_mutex);
4946 * Now that we hold ctx::mutex and child_mutex, revalidate our
4947 * state, if child is still the first entry, it didn't get freed
4948 * and we can continue doing so.
4950 tmp = list_first_entry_or_null(&event->child_list,
4951 struct perf_event, child_list);
4953 perf_remove_from_context(child, DETACH_GROUP);
4954 list_move(&child->child_list, &free_list);
4956 * This matches the refcount bump in inherit_event();
4957 * this can't be the last reference.
4962 mutex_unlock(&event->child_mutex);
4963 mutex_unlock(&ctx->mutex);
4967 mutex_unlock(&event->child_mutex);
4969 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4970 void *var = &child->ctx->refcount;
4972 list_del(&child->child_list);
4976 * Wake any perf_event_free_task() waiting for this event to be
4979 smp_mb(); /* pairs with wait_var_event() */
4984 put_event(event); /* Must be the 'last' reference */
4987 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4990 * Called when the last reference to the file is gone.
4992 static int perf_release(struct inode *inode, struct file *file)
4994 perf_event_release_kernel(file->private_data);
4998 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5000 struct perf_event *child;
5006 mutex_lock(&event->child_mutex);
5008 (void)perf_event_read(event, false);
5009 total += perf_event_count(event);
5011 *enabled += event->total_time_enabled +
5012 atomic64_read(&event->child_total_time_enabled);
5013 *running += event->total_time_running +
5014 atomic64_read(&event->child_total_time_running);
5016 list_for_each_entry(child, &event->child_list, child_list) {
5017 (void)perf_event_read(child, false);
5018 total += perf_event_count(child);
5019 *enabled += child->total_time_enabled;
5020 *running += child->total_time_running;
5022 mutex_unlock(&event->child_mutex);
5027 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5029 struct perf_event_context *ctx;
5032 ctx = perf_event_ctx_lock(event);
5033 count = __perf_event_read_value(event, enabled, running);
5034 perf_event_ctx_unlock(event, ctx);
5038 EXPORT_SYMBOL_GPL(perf_event_read_value);
5040 static int __perf_read_group_add(struct perf_event *leader,
5041 u64 read_format, u64 *values)
5043 struct perf_event_context *ctx = leader->ctx;
5044 struct perf_event *sub;
5045 unsigned long flags;
5046 int n = 1; /* skip @nr */
5049 ret = perf_event_read(leader, true);
5053 raw_spin_lock_irqsave(&ctx->lock, flags);
5056 * Since we co-schedule groups, {enabled,running} times of siblings
5057 * will be identical to those of the leader, so we only publish one
5060 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5061 values[n++] += leader->total_time_enabled +
5062 atomic64_read(&leader->child_total_time_enabled);
5065 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5066 values[n++] += leader->total_time_running +
5067 atomic64_read(&leader->child_total_time_running);
5071 * Write {count,id} tuples for every sibling.
5073 values[n++] += perf_event_count(leader);
5074 if (read_format & PERF_FORMAT_ID)
5075 values[n++] = primary_event_id(leader);
5077 for_each_sibling_event(sub, leader) {
5078 values[n++] += perf_event_count(sub);
5079 if (read_format & PERF_FORMAT_ID)
5080 values[n++] = primary_event_id(sub);
5083 raw_spin_unlock_irqrestore(&ctx->lock, flags);
5087 static int perf_read_group(struct perf_event *event,
5088 u64 read_format, char __user *buf)
5090 struct perf_event *leader = event->group_leader, *child;
5091 struct perf_event_context *ctx = leader->ctx;
5095 lockdep_assert_held(&ctx->mutex);
5097 values = kzalloc(event->read_size, GFP_KERNEL);
5101 values[0] = 1 + leader->nr_siblings;
5104 * By locking the child_mutex of the leader we effectively
5105 * lock the child list of all siblings.. XXX explain how.
5107 mutex_lock(&leader->child_mutex);
5109 ret = __perf_read_group_add(leader, read_format, values);
5113 list_for_each_entry(child, &leader->child_list, child_list) {
5114 ret = __perf_read_group_add(child, read_format, values);
5119 mutex_unlock(&leader->child_mutex);
5121 ret = event->read_size;
5122 if (copy_to_user(buf, values, event->read_size))
5127 mutex_unlock(&leader->child_mutex);
5133 static int perf_read_one(struct perf_event *event,
5134 u64 read_format, char __user *buf)
5136 u64 enabled, running;
5140 values[n++] = __perf_event_read_value(event, &enabled, &running);
5141 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5142 values[n++] = enabled;
5143 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5144 values[n++] = running;
5145 if (read_format & PERF_FORMAT_ID)
5146 values[n++] = primary_event_id(event);
5148 if (copy_to_user(buf, values, n * sizeof(u64)))
5151 return n * sizeof(u64);
5154 static bool is_event_hup(struct perf_event *event)
5158 if (event->state > PERF_EVENT_STATE_EXIT)
5161 mutex_lock(&event->child_mutex);
5162 no_children = list_empty(&event->child_list);
5163 mutex_unlock(&event->child_mutex);
5168 * Read the performance event - simple non blocking version for now
5171 __perf_read(struct perf_event *event, char __user *buf, size_t count)
5173 u64 read_format = event->attr.read_format;
5177 * Return end-of-file for a read on an event that is in
5178 * error state (i.e. because it was pinned but it couldn't be
5179 * scheduled on to the CPU at some point).
5181 if (event->state == PERF_EVENT_STATE_ERROR)
5184 if (count < event->read_size)
5187 WARN_ON_ONCE(event->ctx->parent_ctx);
5188 if (read_format & PERF_FORMAT_GROUP)
5189 ret = perf_read_group(event, read_format, buf);
5191 ret = perf_read_one(event, read_format, buf);
5197 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
5199 struct perf_event *event = file->private_data;
5200 struct perf_event_context *ctx;
5203 ret = security_perf_event_read(event);
5207 ctx = perf_event_ctx_lock(event);
5208 ret = __perf_read(event, buf, count);
5209 perf_event_ctx_unlock(event, ctx);
5214 static __poll_t perf_poll(struct file *file, poll_table *wait)
5216 struct perf_event *event = file->private_data;
5217 struct perf_buffer *rb;
5218 __poll_t events = EPOLLHUP;
5220 poll_wait(file, &event->waitq, wait);
5222 if (is_event_hup(event))
5226 * Pin the event->rb by taking event->mmap_mutex; otherwise
5227 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5229 mutex_lock(&event->mmap_mutex);
5232 events = atomic_xchg(&rb->poll, 0);
5233 mutex_unlock(&event->mmap_mutex);
5237 static void _perf_event_reset(struct perf_event *event)
5239 (void)perf_event_read(event, false);
5240 local64_set(&event->count, 0);
5241 perf_event_update_userpage(event);
5244 /* Assume it's not an event with inherit set. */
5245 u64 perf_event_pause(struct perf_event *event, bool reset)
5247 struct perf_event_context *ctx;
5250 ctx = perf_event_ctx_lock(event);
5251 WARN_ON_ONCE(event->attr.inherit);
5252 _perf_event_disable(event);
5253 count = local64_read(&event->count);
5255 local64_set(&event->count, 0);
5256 perf_event_ctx_unlock(event, ctx);
5260 EXPORT_SYMBOL_GPL(perf_event_pause);
5263 * Holding the top-level event's child_mutex means that any
5264 * descendant process that has inherited this event will block
5265 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5266 * task existence requirements of perf_event_enable/disable.
5268 static void perf_event_for_each_child(struct perf_event *event,
5269 void (*func)(struct perf_event *))
5271 struct perf_event *child;
5273 WARN_ON_ONCE(event->ctx->parent_ctx);
5275 mutex_lock(&event->child_mutex);
5277 list_for_each_entry(child, &event->child_list, child_list)
5279 mutex_unlock(&event->child_mutex);
5282 static void perf_event_for_each(struct perf_event *event,
5283 void (*func)(struct perf_event *))
5285 struct perf_event_context *ctx = event->ctx;
5286 struct perf_event *sibling;
5288 lockdep_assert_held(&ctx->mutex);
5290 event = event->group_leader;
5292 perf_event_for_each_child(event, func);
5293 for_each_sibling_event(sibling, event)
5294 perf_event_for_each_child(sibling, func);
5297 static void __perf_event_period(struct perf_event *event,
5298 struct perf_cpu_context *cpuctx,
5299 struct perf_event_context *ctx,
5302 u64 value = *((u64 *)info);
5305 if (event->attr.freq) {
5306 event->attr.sample_freq = value;
5308 event->attr.sample_period = value;
5309 event->hw.sample_period = value;
5312 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5314 perf_pmu_disable(ctx->pmu);
5316 * We could be throttled; unthrottle now to avoid the tick
5317 * trying to unthrottle while we already re-started the event.
5319 if (event->hw.interrupts == MAX_INTERRUPTS) {
5320 event->hw.interrupts = 0;
5321 perf_log_throttle(event, 1);
5323 event->pmu->stop(event, PERF_EF_UPDATE);
5326 local64_set(&event->hw.period_left, 0);
5329 event->pmu->start(event, PERF_EF_RELOAD);
5330 perf_pmu_enable(ctx->pmu);
5334 static int perf_event_check_period(struct perf_event *event, u64 value)
5336 return event->pmu->check_period(event, value);
5339 static int _perf_event_period(struct perf_event *event, u64 value)
5341 if (!is_sampling_event(event))
5347 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5350 if (perf_event_check_period(event, value))
5353 if (!event->attr.freq && (value & (1ULL << 63)))
5356 event_function_call(event, __perf_event_period, &value);
5361 int perf_event_period(struct perf_event *event, u64 value)
5363 struct perf_event_context *ctx;
5366 ctx = perf_event_ctx_lock(event);
5367 ret = _perf_event_period(event, value);
5368 perf_event_ctx_unlock(event, ctx);
5372 EXPORT_SYMBOL_GPL(perf_event_period);
5374 static const struct file_operations perf_fops;
5376 static inline int perf_fget_light(int fd, struct fd *p)
5378 struct fd f = fdget(fd);
5382 if (f.file->f_op != &perf_fops) {
5390 static int perf_event_set_output(struct perf_event *event,
5391 struct perf_event *output_event);
5392 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5393 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5394 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5395 struct perf_event_attr *attr);
5397 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5399 void (*func)(struct perf_event *);
5403 case PERF_EVENT_IOC_ENABLE:
5404 func = _perf_event_enable;
5406 case PERF_EVENT_IOC_DISABLE:
5407 func = _perf_event_disable;
5409 case PERF_EVENT_IOC_RESET:
5410 func = _perf_event_reset;
5413 case PERF_EVENT_IOC_REFRESH:
5414 return _perf_event_refresh(event, arg);
5416 case PERF_EVENT_IOC_PERIOD:
5420 if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
5423 return _perf_event_period(event, value);
5425 case PERF_EVENT_IOC_ID:
5427 u64 id = primary_event_id(event);
5429 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5434 case PERF_EVENT_IOC_SET_OUTPUT:
5438 struct perf_event *output_event;
5440 ret = perf_fget_light(arg, &output);
5443 output_event = output.file->private_data;
5444 ret = perf_event_set_output(event, output_event);
5447 ret = perf_event_set_output(event, NULL);
5452 case PERF_EVENT_IOC_SET_FILTER:
5453 return perf_event_set_filter(event, (void __user *)arg);
5455 case PERF_EVENT_IOC_SET_BPF:
5456 return perf_event_set_bpf_prog(event, arg);
5458 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5459 struct perf_buffer *rb;
5462 rb = rcu_dereference(event->rb);
5463 if (!rb || !rb->nr_pages) {
5467 rb_toggle_paused(rb, !!arg);
5472 case PERF_EVENT_IOC_QUERY_BPF:
5473 return perf_event_query_prog_array(event, (void __user *)arg);
5475 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5476 struct perf_event_attr new_attr;
5477 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5483 return perf_event_modify_attr(event, &new_attr);
5489 if (flags & PERF_IOC_FLAG_GROUP)
5490 perf_event_for_each(event, func);
5492 perf_event_for_each_child(event, func);
5497 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5499 struct perf_event *event = file->private_data;
5500 struct perf_event_context *ctx;
5503 /* Treat ioctl like writes as it is likely a mutating operation. */
5504 ret = security_perf_event_write(event);
5508 ctx = perf_event_ctx_lock(event);
5509 ret = _perf_ioctl(event, cmd, arg);
5510 perf_event_ctx_unlock(event, ctx);
5515 #ifdef CONFIG_COMPAT
5516 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5519 switch (_IOC_NR(cmd)) {
5520 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5521 case _IOC_NR(PERF_EVENT_IOC_ID):
5522 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5523 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5524 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5525 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5526 cmd &= ~IOCSIZE_MASK;
5527 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5531 return perf_ioctl(file, cmd, arg);
5534 # define perf_compat_ioctl NULL
5537 int perf_event_task_enable(void)
5539 struct perf_event_context *ctx;
5540 struct perf_event *event;
5542 mutex_lock(¤t->perf_event_mutex);
5543 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5544 ctx = perf_event_ctx_lock(event);
5545 perf_event_for_each_child(event, _perf_event_enable);
5546 perf_event_ctx_unlock(event, ctx);
5548 mutex_unlock(¤t->perf_event_mutex);
5553 int perf_event_task_disable(void)
5555 struct perf_event_context *ctx;
5556 struct perf_event *event;
5558 mutex_lock(¤t->perf_event_mutex);
5559 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5560 ctx = perf_event_ctx_lock(event);
5561 perf_event_for_each_child(event, _perf_event_disable);
5562 perf_event_ctx_unlock(event, ctx);
5564 mutex_unlock(¤t->perf_event_mutex);
5569 static int perf_event_index(struct perf_event *event)
5571 if (event->hw.state & PERF_HES_STOPPED)
5574 if (event->state != PERF_EVENT_STATE_ACTIVE)
5577 return event->pmu->event_idx(event);
5580 static void calc_timer_values(struct perf_event *event,
5587 *now = perf_clock();
5588 ctx_time = event->shadow_ctx_time + *now;
5589 __perf_update_times(event, ctx_time, enabled, running);
5592 static void perf_event_init_userpage(struct perf_event *event)
5594 struct perf_event_mmap_page *userpg;
5595 struct perf_buffer *rb;
5598 rb = rcu_dereference(event->rb);
5602 userpg = rb->user_page;
5604 /* Allow new userspace to detect that bit 0 is deprecated */
5605 userpg->cap_bit0_is_deprecated = 1;
5606 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5607 userpg->data_offset = PAGE_SIZE;
5608 userpg->data_size = perf_data_size(rb);
5614 void __weak arch_perf_update_userpage(
5615 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5620 * Callers need to ensure there can be no nesting of this function, otherwise
5621 * the seqlock logic goes bad. We can not serialize this because the arch
5622 * code calls this from NMI context.
5624 void perf_event_update_userpage(struct perf_event *event)
5626 struct perf_event_mmap_page *userpg;
5627 struct perf_buffer *rb;
5628 u64 enabled, running, now;
5631 rb = rcu_dereference(event->rb);
5636 * compute total_time_enabled, total_time_running
5637 * based on snapshot values taken when the event
5638 * was last scheduled in.
5640 * we cannot simply called update_context_time()
5641 * because of locking issue as we can be called in
5644 calc_timer_values(event, &now, &enabled, &running);
5646 userpg = rb->user_page;
5648 * Disable preemption to guarantee consistent time stamps are stored to
5654 userpg->index = perf_event_index(event);
5655 userpg->offset = perf_event_count(event);
5657 userpg->offset -= local64_read(&event->hw.prev_count);
5659 userpg->time_enabled = enabled +
5660 atomic64_read(&event->child_total_time_enabled);
5662 userpg->time_running = running +
5663 atomic64_read(&event->child_total_time_running);
5665 arch_perf_update_userpage(event, userpg, now);
5673 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5675 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5677 struct perf_event *event = vmf->vma->vm_file->private_data;
5678 struct perf_buffer *rb;
5679 vm_fault_t ret = VM_FAULT_SIGBUS;
5681 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5682 if (vmf->pgoff == 0)
5688 rb = rcu_dereference(event->rb);
5692 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5695 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5699 get_page(vmf->page);
5700 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5701 vmf->page->index = vmf->pgoff;
5710 static void ring_buffer_attach(struct perf_event *event,
5711 struct perf_buffer *rb)
5713 struct perf_buffer *old_rb = NULL;
5714 unsigned long flags;
5718 * Should be impossible, we set this when removing
5719 * event->rb_entry and wait/clear when adding event->rb_entry.
5721 WARN_ON_ONCE(event->rcu_pending);
5724 spin_lock_irqsave(&old_rb->event_lock, flags);
5725 list_del_rcu(&event->rb_entry);
5726 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5728 event->rcu_batches = get_state_synchronize_rcu();
5729 event->rcu_pending = 1;
5733 if (event->rcu_pending) {
5734 cond_synchronize_rcu(event->rcu_batches);
5735 event->rcu_pending = 0;
5738 spin_lock_irqsave(&rb->event_lock, flags);
5739 list_add_rcu(&event->rb_entry, &rb->event_list);
5740 spin_unlock_irqrestore(&rb->event_lock, flags);
5744 * Avoid racing with perf_mmap_close(AUX): stop the event
5745 * before swizzling the event::rb pointer; if it's getting
5746 * unmapped, its aux_mmap_count will be 0 and it won't
5747 * restart. See the comment in __perf_pmu_output_stop().
5749 * Data will inevitably be lost when set_output is done in
5750 * mid-air, but then again, whoever does it like this is
5751 * not in for the data anyway.
5754 perf_event_stop(event, 0);
5756 rcu_assign_pointer(event->rb, rb);
5759 ring_buffer_put(old_rb);
5761 * Since we detached before setting the new rb, so that we
5762 * could attach the new rb, we could have missed a wakeup.
5765 wake_up_all(&event->waitq);
5769 static void ring_buffer_wakeup(struct perf_event *event)
5771 struct perf_buffer *rb;
5774 rb = rcu_dereference(event->rb);
5776 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5777 wake_up_all(&event->waitq);
5782 struct perf_buffer *ring_buffer_get(struct perf_event *event)
5784 struct perf_buffer *rb;
5787 rb = rcu_dereference(event->rb);
5789 if (!refcount_inc_not_zero(&rb->refcount))
5797 void ring_buffer_put(struct perf_buffer *rb)
5799 if (!refcount_dec_and_test(&rb->refcount))
5802 WARN_ON_ONCE(!list_empty(&rb->event_list));
5804 call_rcu(&rb->rcu_head, rb_free_rcu);
5807 static void perf_mmap_open(struct vm_area_struct *vma)
5809 struct perf_event *event = vma->vm_file->private_data;
5811 atomic_inc(&event->mmap_count);
5812 atomic_inc(&event->rb->mmap_count);
5815 atomic_inc(&event->rb->aux_mmap_count);
5817 if (event->pmu->event_mapped)
5818 event->pmu->event_mapped(event, vma->vm_mm);
5821 static void perf_pmu_output_stop(struct perf_event *event);
5824 * A buffer can be mmap()ed multiple times; either directly through the same
5825 * event, or through other events by use of perf_event_set_output().
5827 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5828 * the buffer here, where we still have a VM context. This means we need
5829 * to detach all events redirecting to us.
5831 static void perf_mmap_close(struct vm_area_struct *vma)
5833 struct perf_event *event = vma->vm_file->private_data;
5835 struct perf_buffer *rb = ring_buffer_get(event);
5836 struct user_struct *mmap_user = rb->mmap_user;
5837 int mmap_locked = rb->mmap_locked;
5838 unsigned long size = perf_data_size(rb);
5840 if (event->pmu->event_unmapped)
5841 event->pmu->event_unmapped(event, vma->vm_mm);
5844 * rb->aux_mmap_count will always drop before rb->mmap_count and
5845 * event->mmap_count, so it is ok to use event->mmap_mutex to
5846 * serialize with perf_mmap here.
5848 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5849 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5851 * Stop all AUX events that are writing to this buffer,
5852 * so that we can free its AUX pages and corresponding PMU
5853 * data. Note that after rb::aux_mmap_count dropped to zero,
5854 * they won't start any more (see perf_aux_output_begin()).
5856 perf_pmu_output_stop(event);
5858 /* now it's safe to free the pages */
5859 atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
5860 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
5862 /* this has to be the last one */
5864 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
5866 mutex_unlock(&event->mmap_mutex);
5869 atomic_dec(&rb->mmap_count);
5871 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5874 ring_buffer_attach(event, NULL);
5875 mutex_unlock(&event->mmap_mutex);
5877 /* If there's still other mmap()s of this buffer, we're done. */
5878 if (atomic_read(&rb->mmap_count))
5882 * No other mmap()s, detach from all other events that might redirect
5883 * into the now unreachable buffer. Somewhat complicated by the
5884 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5888 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5889 if (!atomic_long_inc_not_zero(&event->refcount)) {
5891 * This event is en-route to free_event() which will
5892 * detach it and remove it from the list.
5898 mutex_lock(&event->mmap_mutex);
5900 * Check we didn't race with perf_event_set_output() which can
5901 * swizzle the rb from under us while we were waiting to
5902 * acquire mmap_mutex.
5904 * If we find a different rb; ignore this event, a next
5905 * iteration will no longer find it on the list. We have to
5906 * still restart the iteration to make sure we're not now
5907 * iterating the wrong list.
5909 if (event->rb == rb)
5910 ring_buffer_attach(event, NULL);
5912 mutex_unlock(&event->mmap_mutex);
5916 * Restart the iteration; either we're on the wrong list or
5917 * destroyed its integrity by doing a deletion.
5924 * It could be there's still a few 0-ref events on the list; they'll
5925 * get cleaned up by free_event() -- they'll also still have their
5926 * ref on the rb and will free it whenever they are done with it.
5928 * Aside from that, this buffer is 'fully' detached and unmapped,
5929 * undo the VM accounting.
5932 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
5933 &mmap_user->locked_vm);
5934 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
5935 free_uid(mmap_user);
5938 ring_buffer_put(rb); /* could be last */
5941 static const struct vm_operations_struct perf_mmap_vmops = {
5942 .open = perf_mmap_open,
5943 .close = perf_mmap_close, /* non mergeable */
5944 .fault = perf_mmap_fault,
5945 .page_mkwrite = perf_mmap_fault,
5948 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5950 struct perf_event *event = file->private_data;
5951 unsigned long user_locked, user_lock_limit;
5952 struct user_struct *user = current_user();
5953 struct perf_buffer *rb = NULL;
5954 unsigned long locked, lock_limit;
5955 unsigned long vma_size;
5956 unsigned long nr_pages;
5957 long user_extra = 0, extra = 0;
5958 int ret = 0, flags = 0;
5961 * Don't allow mmap() of inherited per-task counters. This would
5962 * create a performance issue due to all children writing to the
5965 if (event->cpu == -1 && event->attr.inherit)
5968 if (!(vma->vm_flags & VM_SHARED))
5971 ret = security_perf_event_read(event);
5975 vma_size = vma->vm_end - vma->vm_start;
5977 if (vma->vm_pgoff == 0) {
5978 nr_pages = (vma_size / PAGE_SIZE) - 1;
5981 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5982 * mapped, all subsequent mappings should have the same size
5983 * and offset. Must be above the normal perf buffer.
5985 u64 aux_offset, aux_size;
5990 nr_pages = vma_size / PAGE_SIZE;
5992 mutex_lock(&event->mmap_mutex);
5999 aux_offset = READ_ONCE(rb->user_page->aux_offset);
6000 aux_size = READ_ONCE(rb->user_page->aux_size);
6002 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
6005 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
6008 /* already mapped with a different offset */
6009 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
6012 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
6015 /* already mapped with a different size */
6016 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
6019 if (!is_power_of_2(nr_pages))
6022 if (!atomic_inc_not_zero(&rb->mmap_count))
6025 if (rb_has_aux(rb)) {
6026 atomic_inc(&rb->aux_mmap_count);
6031 atomic_set(&rb->aux_mmap_count, 1);
6032 user_extra = nr_pages;
6038 * If we have rb pages ensure they're a power-of-two number, so we
6039 * can do bitmasks instead of modulo.
6041 if (nr_pages != 0 && !is_power_of_2(nr_pages))
6044 if (vma_size != PAGE_SIZE * (1 + nr_pages))
6047 WARN_ON_ONCE(event->ctx->parent_ctx);
6049 mutex_lock(&event->mmap_mutex);
6051 if (event->rb->nr_pages != nr_pages) {
6056 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
6058 * Raced against perf_mmap_close() through
6059 * perf_event_set_output(). Try again, hope for better
6062 mutex_unlock(&event->mmap_mutex);
6069 user_extra = nr_pages + 1;
6072 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
6075 * Increase the limit linearly with more CPUs:
6077 user_lock_limit *= num_online_cpus();
6079 user_locked = atomic_long_read(&user->locked_vm);
6082 * sysctl_perf_event_mlock may have changed, so that
6083 * user->locked_vm > user_lock_limit
6085 if (user_locked > user_lock_limit)
6086 user_locked = user_lock_limit;
6087 user_locked += user_extra;
6089 if (user_locked > user_lock_limit) {
6091 * charge locked_vm until it hits user_lock_limit;
6092 * charge the rest from pinned_vm
6094 extra = user_locked - user_lock_limit;
6095 user_extra -= extra;
6098 lock_limit = rlimit(RLIMIT_MEMLOCK);
6099 lock_limit >>= PAGE_SHIFT;
6100 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
6102 if ((locked > lock_limit) && perf_is_paranoid() &&
6103 !capable(CAP_IPC_LOCK)) {
6108 WARN_ON(!rb && event->rb);
6110 if (vma->vm_flags & VM_WRITE)
6111 flags |= RING_BUFFER_WRITABLE;
6114 rb = rb_alloc(nr_pages,
6115 event->attr.watermark ? event->attr.wakeup_watermark : 0,
6123 atomic_set(&rb->mmap_count, 1);
6124 rb->mmap_user = get_current_user();
6125 rb->mmap_locked = extra;
6127 ring_buffer_attach(event, rb);
6129 perf_event_init_userpage(event);
6130 perf_event_update_userpage(event);
6132 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
6133 event->attr.aux_watermark, flags);
6135 rb->aux_mmap_locked = extra;
6140 atomic_long_add(user_extra, &user->locked_vm);
6141 atomic64_add(extra, &vma->vm_mm->pinned_vm);
6143 atomic_inc(&event->mmap_count);
6145 atomic_dec(&rb->mmap_count);
6148 mutex_unlock(&event->mmap_mutex);
6151 * Since pinned accounting is per vm we cannot allow fork() to copy our
6154 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
6155 vma->vm_ops = &perf_mmap_vmops;
6157 if (event->pmu->event_mapped)
6158 event->pmu->event_mapped(event, vma->vm_mm);
6163 static int perf_fasync(int fd, struct file *filp, int on)
6165 struct inode *inode = file_inode(filp);
6166 struct perf_event *event = filp->private_data;
6170 retval = fasync_helper(fd, filp, on, &event->fasync);
6171 inode_unlock(inode);
6179 static const struct file_operations perf_fops = {
6180 .llseek = no_llseek,
6181 .release = perf_release,
6184 .unlocked_ioctl = perf_ioctl,
6185 .compat_ioctl = perf_compat_ioctl,
6187 .fasync = perf_fasync,
6193 * If there's data, ensure we set the poll() state and publish everything
6194 * to user-space before waking everybody up.
6197 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
6199 /* only the parent has fasync state */
6201 event = event->parent;
6202 return &event->fasync;
6205 void perf_event_wakeup(struct perf_event *event)
6207 ring_buffer_wakeup(event);
6209 if (event->pending_kill) {
6210 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
6211 event->pending_kill = 0;
6215 static void perf_pending_event_disable(struct perf_event *event)
6217 int cpu = READ_ONCE(event->pending_disable);
6222 if (cpu == smp_processor_id()) {
6223 WRITE_ONCE(event->pending_disable, -1);
6224 perf_event_disable_local(event);
6231 * perf_event_disable_inatomic()
6232 * @pending_disable = CPU-A;
6236 * @pending_disable = -1;
6239 * perf_event_disable_inatomic()
6240 * @pending_disable = CPU-B;
6241 * irq_work_queue(); // FAILS
6244 * perf_pending_event()
6246 * But the event runs on CPU-B and wants disabling there.
6248 irq_work_queue_on(&event->pending, cpu);
6251 static void perf_pending_event(struct irq_work *entry)
6253 struct perf_event *event = container_of(entry, struct perf_event, pending);
6256 rctx = perf_swevent_get_recursion_context();
6258 * If we 'fail' here, that's OK, it means recursion is already disabled
6259 * and we won't recurse 'further'.
6262 perf_pending_event_disable(event);
6264 if (event->pending_wakeup) {
6265 event->pending_wakeup = 0;
6266 perf_event_wakeup(event);
6270 perf_swevent_put_recursion_context(rctx);
6274 * We assume there is only KVM supporting the callbacks.
6275 * Later on, we might change it to a list if there is
6276 * another virtualization implementation supporting the callbacks.
6278 struct perf_guest_info_callbacks *perf_guest_cbs;
6280 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6282 perf_guest_cbs = cbs;
6285 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6287 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6289 perf_guest_cbs = NULL;
6292 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6295 perf_output_sample_regs(struct perf_output_handle *handle,
6296 struct pt_regs *regs, u64 mask)
6299 DECLARE_BITMAP(_mask, 64);
6301 bitmap_from_u64(_mask, mask);
6302 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6305 val = perf_reg_value(regs, bit);
6306 perf_output_put(handle, val);
6310 static void perf_sample_regs_user(struct perf_regs *regs_user,
6311 struct pt_regs *regs,
6312 struct pt_regs *regs_user_copy)
6314 if (user_mode(regs)) {
6315 regs_user->abi = perf_reg_abi(current);
6316 regs_user->regs = regs;
6317 } else if (!(current->flags & PF_KTHREAD)) {
6318 perf_get_regs_user(regs_user, regs, regs_user_copy);
6320 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6321 regs_user->regs = NULL;
6325 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6326 struct pt_regs *regs)
6328 regs_intr->regs = regs;
6329 regs_intr->abi = perf_reg_abi(current);
6334 * Get remaining task size from user stack pointer.
6336 * It'd be better to take stack vma map and limit this more
6337 * precisely, but there's no way to get it safely under interrupt,
6338 * so using TASK_SIZE as limit.
6340 static u64 perf_ustack_task_size(struct pt_regs *regs)
6342 unsigned long addr = perf_user_stack_pointer(regs);
6344 if (!addr || addr >= TASK_SIZE)
6347 return TASK_SIZE - addr;
6351 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6352 struct pt_regs *regs)
6356 /* No regs, no stack pointer, no dump. */
6361 * Check if we fit in with the requested stack size into the:
6363 * If we don't, we limit the size to the TASK_SIZE.
6365 * - remaining sample size
6366 * If we don't, we customize the stack size to
6367 * fit in to the remaining sample size.
6370 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6371 stack_size = min(stack_size, (u16) task_size);
6373 /* Current header size plus static size and dynamic size. */
6374 header_size += 2 * sizeof(u64);
6376 /* Do we fit in with the current stack dump size? */
6377 if ((u16) (header_size + stack_size) < header_size) {
6379 * If we overflow the maximum size for the sample,
6380 * we customize the stack dump size to fit in.
6382 stack_size = USHRT_MAX - header_size - sizeof(u64);
6383 stack_size = round_up(stack_size, sizeof(u64));
6390 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6391 struct pt_regs *regs)
6393 /* Case of a kernel thread, nothing to dump */
6396 perf_output_put(handle, size);
6406 * - the size requested by user or the best one we can fit
6407 * in to the sample max size
6409 * - user stack dump data
6411 * - the actual dumped size
6415 perf_output_put(handle, dump_size);
6418 sp = perf_user_stack_pointer(regs);
6421 rem = __output_copy_user(handle, (void *) sp, dump_size);
6423 dyn_size = dump_size - rem;
6425 perf_output_skip(handle, rem);
6428 perf_output_put(handle, dyn_size);
6432 static unsigned long perf_prepare_sample_aux(struct perf_event *event,
6433 struct perf_sample_data *data,
6436 struct perf_event *sampler = event->aux_event;
6437 struct perf_buffer *rb;
6444 if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
6447 if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
6450 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6455 * If this is an NMI hit inside sampling code, don't take
6456 * the sample. See also perf_aux_sample_output().
6458 if (READ_ONCE(rb->aux_in_sampling)) {
6461 size = min_t(size_t, size, perf_aux_size(rb));
6462 data->aux_size = ALIGN(size, sizeof(u64));
6464 ring_buffer_put(rb);
6467 return data->aux_size;
6470 long perf_pmu_snapshot_aux(struct perf_buffer *rb,
6471 struct perf_event *event,
6472 struct perf_output_handle *handle,
6475 unsigned long flags;
6479 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
6480 * paths. If we start calling them in NMI context, they may race with
6481 * the IRQ ones, that is, for example, re-starting an event that's just
6482 * been stopped, which is why we're using a separate callback that
6483 * doesn't change the event state.
6485 * IRQs need to be disabled to prevent IPIs from racing with us.
6487 local_irq_save(flags);
6489 * Guard against NMI hits inside the critical section;
6490 * see also perf_prepare_sample_aux().
6492 WRITE_ONCE(rb->aux_in_sampling, 1);
6495 ret = event->pmu->snapshot_aux(event, handle, size);
6498 WRITE_ONCE(rb->aux_in_sampling, 0);
6499 local_irq_restore(flags);
6504 static void perf_aux_sample_output(struct perf_event *event,
6505 struct perf_output_handle *handle,
6506 struct perf_sample_data *data)
6508 struct perf_event *sampler = event->aux_event;
6509 struct perf_buffer *rb;
6513 if (WARN_ON_ONCE(!sampler || !data->aux_size))
6516 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6520 size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
6523 * An error here means that perf_output_copy() failed (returned a
6524 * non-zero surplus that it didn't copy), which in its current
6525 * enlightened implementation is not possible. If that changes, we'd
6528 if (WARN_ON_ONCE(size < 0))
6532 * The pad comes from ALIGN()ing data->aux_size up to u64 in
6533 * perf_prepare_sample_aux(), so should not be more than that.
6535 pad = data->aux_size - size;
6536 if (WARN_ON_ONCE(pad >= sizeof(u64)))
6541 perf_output_copy(handle, &zero, pad);
6545 ring_buffer_put(rb);
6548 static void __perf_event_header__init_id(struct perf_event_header *header,
6549 struct perf_sample_data *data,
6550 struct perf_event *event)
6552 u64 sample_type = event->attr.sample_type;
6554 data->type = sample_type;
6555 header->size += event->id_header_size;
6557 if (sample_type & PERF_SAMPLE_TID) {
6558 /* namespace issues */
6559 data->tid_entry.pid = perf_event_pid(event, current);
6560 data->tid_entry.tid = perf_event_tid(event, current);
6563 if (sample_type & PERF_SAMPLE_TIME)
6564 data->time = perf_event_clock(event);
6566 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6567 data->id = primary_event_id(event);
6569 if (sample_type & PERF_SAMPLE_STREAM_ID)
6570 data->stream_id = event->id;
6572 if (sample_type & PERF_SAMPLE_CPU) {
6573 data->cpu_entry.cpu = raw_smp_processor_id();
6574 data->cpu_entry.reserved = 0;
6578 void perf_event_header__init_id(struct perf_event_header *header,
6579 struct perf_sample_data *data,
6580 struct perf_event *event)
6582 if (event->attr.sample_id_all)
6583 __perf_event_header__init_id(header, data, event);
6586 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6587 struct perf_sample_data *data)
6589 u64 sample_type = data->type;
6591 if (sample_type & PERF_SAMPLE_TID)
6592 perf_output_put(handle, data->tid_entry);
6594 if (sample_type & PERF_SAMPLE_TIME)
6595 perf_output_put(handle, data->time);
6597 if (sample_type & PERF_SAMPLE_ID)
6598 perf_output_put(handle, data->id);
6600 if (sample_type & PERF_SAMPLE_STREAM_ID)
6601 perf_output_put(handle, data->stream_id);
6603 if (sample_type & PERF_SAMPLE_CPU)
6604 perf_output_put(handle, data->cpu_entry);
6606 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6607 perf_output_put(handle, data->id);
6610 void perf_event__output_id_sample(struct perf_event *event,
6611 struct perf_output_handle *handle,
6612 struct perf_sample_data *sample)
6614 if (event->attr.sample_id_all)
6615 __perf_event__output_id_sample(handle, sample);
6618 static void perf_output_read_one(struct perf_output_handle *handle,
6619 struct perf_event *event,
6620 u64 enabled, u64 running)
6622 u64 read_format = event->attr.read_format;
6626 values[n++] = perf_event_count(event);
6627 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6628 values[n++] = enabled +
6629 atomic64_read(&event->child_total_time_enabled);
6631 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6632 values[n++] = running +
6633 atomic64_read(&event->child_total_time_running);
6635 if (read_format & PERF_FORMAT_ID)
6636 values[n++] = primary_event_id(event);
6638 __output_copy(handle, values, n * sizeof(u64));
6641 static void perf_output_read_group(struct perf_output_handle *handle,
6642 struct perf_event *event,
6643 u64 enabled, u64 running)
6645 struct perf_event *leader = event->group_leader, *sub;
6646 u64 read_format = event->attr.read_format;
6650 values[n++] = 1 + leader->nr_siblings;
6652 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6653 values[n++] = enabled;
6655 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6656 values[n++] = running;
6658 if ((leader != event) &&
6659 (leader->state == PERF_EVENT_STATE_ACTIVE))
6660 leader->pmu->read(leader);
6662 values[n++] = perf_event_count(leader);
6663 if (read_format & PERF_FORMAT_ID)
6664 values[n++] = primary_event_id(leader);
6666 __output_copy(handle, values, n * sizeof(u64));
6668 for_each_sibling_event(sub, leader) {
6671 if ((sub != event) &&
6672 (sub->state == PERF_EVENT_STATE_ACTIVE))
6673 sub->pmu->read(sub);
6675 values[n++] = perf_event_count(sub);
6676 if (read_format & PERF_FORMAT_ID)
6677 values[n++] = primary_event_id(sub);
6679 __output_copy(handle, values, n * sizeof(u64));
6683 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6684 PERF_FORMAT_TOTAL_TIME_RUNNING)
6687 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6689 * The problem is that its both hard and excessively expensive to iterate the
6690 * child list, not to mention that its impossible to IPI the children running
6691 * on another CPU, from interrupt/NMI context.
6693 static void perf_output_read(struct perf_output_handle *handle,
6694 struct perf_event *event)
6696 u64 enabled = 0, running = 0, now;
6697 u64 read_format = event->attr.read_format;
6700 * compute total_time_enabled, total_time_running
6701 * based on snapshot values taken when the event
6702 * was last scheduled in.
6704 * we cannot simply called update_context_time()
6705 * because of locking issue as we are called in
6708 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6709 calc_timer_values(event, &now, &enabled, &running);
6711 if (event->attr.read_format & PERF_FORMAT_GROUP)
6712 perf_output_read_group(handle, event, enabled, running);
6714 perf_output_read_one(handle, event, enabled, running);
6717 static inline bool perf_sample_save_hw_index(struct perf_event *event)
6719 return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_HW_INDEX;
6722 void perf_output_sample(struct perf_output_handle *handle,
6723 struct perf_event_header *header,
6724 struct perf_sample_data *data,
6725 struct perf_event *event)
6727 u64 sample_type = data->type;
6729 perf_output_put(handle, *header);
6731 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6732 perf_output_put(handle, data->id);
6734 if (sample_type & PERF_SAMPLE_IP)
6735 perf_output_put(handle, data->ip);
6737 if (sample_type & PERF_SAMPLE_TID)
6738 perf_output_put(handle, data->tid_entry);
6740 if (sample_type & PERF_SAMPLE_TIME)
6741 perf_output_put(handle, data->time);
6743 if (sample_type & PERF_SAMPLE_ADDR)
6744 perf_output_put(handle, data->addr);
6746 if (sample_type & PERF_SAMPLE_ID)
6747 perf_output_put(handle, data->id);
6749 if (sample_type & PERF_SAMPLE_STREAM_ID)
6750 perf_output_put(handle, data->stream_id);
6752 if (sample_type & PERF_SAMPLE_CPU)
6753 perf_output_put(handle, data->cpu_entry);
6755 if (sample_type & PERF_SAMPLE_PERIOD)
6756 perf_output_put(handle, data->period);
6758 if (sample_type & PERF_SAMPLE_READ)
6759 perf_output_read(handle, event);
6761 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6764 size += data->callchain->nr;
6765 size *= sizeof(u64);
6766 __output_copy(handle, data->callchain, size);
6769 if (sample_type & PERF_SAMPLE_RAW) {
6770 struct perf_raw_record *raw = data->raw;
6773 struct perf_raw_frag *frag = &raw->frag;
6775 perf_output_put(handle, raw->size);
6778 __output_custom(handle, frag->copy,
6779 frag->data, frag->size);
6781 __output_copy(handle, frag->data,
6784 if (perf_raw_frag_last(frag))
6789 __output_skip(handle, NULL, frag->pad);
6795 .size = sizeof(u32),
6798 perf_output_put(handle, raw);
6802 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6803 if (data->br_stack) {
6806 size = data->br_stack->nr
6807 * sizeof(struct perf_branch_entry);
6809 perf_output_put(handle, data->br_stack->nr);
6810 if (perf_sample_save_hw_index(event))
6811 perf_output_put(handle, data->br_stack->hw_idx);
6812 perf_output_copy(handle, data->br_stack->entries, size);
6815 * we always store at least the value of nr
6818 perf_output_put(handle, nr);
6822 if (sample_type & PERF_SAMPLE_REGS_USER) {
6823 u64 abi = data->regs_user.abi;
6826 * If there are no regs to dump, notice it through
6827 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6829 perf_output_put(handle, abi);
6832 u64 mask = event->attr.sample_regs_user;
6833 perf_output_sample_regs(handle,
6834 data->regs_user.regs,
6839 if (sample_type & PERF_SAMPLE_STACK_USER) {
6840 perf_output_sample_ustack(handle,
6841 data->stack_user_size,
6842 data->regs_user.regs);
6845 if (sample_type & PERF_SAMPLE_WEIGHT)
6846 perf_output_put(handle, data->weight);
6848 if (sample_type & PERF_SAMPLE_DATA_SRC)
6849 perf_output_put(handle, data->data_src.val);
6851 if (sample_type & PERF_SAMPLE_TRANSACTION)
6852 perf_output_put(handle, data->txn);
6854 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6855 u64 abi = data->regs_intr.abi;
6857 * If there are no regs to dump, notice it through
6858 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6860 perf_output_put(handle, abi);
6863 u64 mask = event->attr.sample_regs_intr;
6865 perf_output_sample_regs(handle,
6866 data->regs_intr.regs,
6871 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6872 perf_output_put(handle, data->phys_addr);
6874 if (sample_type & PERF_SAMPLE_CGROUP)
6875 perf_output_put(handle, data->cgroup);
6877 if (sample_type & PERF_SAMPLE_AUX) {
6878 perf_output_put(handle, data->aux_size);
6881 perf_aux_sample_output(event, handle, data);
6884 if (!event->attr.watermark) {
6885 int wakeup_events = event->attr.wakeup_events;
6887 if (wakeup_events) {
6888 struct perf_buffer *rb = handle->rb;
6889 int events = local_inc_return(&rb->events);
6891 if (events >= wakeup_events) {
6892 local_sub(wakeup_events, &rb->events);
6893 local_inc(&rb->wakeup);
6899 static u64 perf_virt_to_phys(u64 virt)
6902 struct page *p = NULL;
6907 if (virt >= TASK_SIZE) {
6908 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6909 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6910 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6911 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6914 * Walking the pages tables for user address.
6915 * Interrupts are disabled, so it prevents any tear down
6916 * of the page tables.
6917 * Try IRQ-safe __get_user_pages_fast first.
6918 * If failed, leave phys_addr as 0.
6920 if ((current->mm != NULL) &&
6921 (__get_user_pages_fast(virt, 1, 0, &p) == 1))
6922 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6931 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6933 struct perf_callchain_entry *
6934 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6936 bool kernel = !event->attr.exclude_callchain_kernel;
6937 bool user = !event->attr.exclude_callchain_user;
6938 /* Disallow cross-task user callchains. */
6939 bool crosstask = event->ctx->task && event->ctx->task != current;
6940 const u32 max_stack = event->attr.sample_max_stack;
6941 struct perf_callchain_entry *callchain;
6943 if (!kernel && !user)
6944 return &__empty_callchain;
6946 callchain = get_perf_callchain(regs, 0, kernel, user,
6947 max_stack, crosstask, true);
6948 return callchain ?: &__empty_callchain;
6951 void perf_prepare_sample(struct perf_event_header *header,
6952 struct perf_sample_data *data,
6953 struct perf_event *event,
6954 struct pt_regs *regs)
6956 u64 sample_type = event->attr.sample_type;
6958 header->type = PERF_RECORD_SAMPLE;
6959 header->size = sizeof(*header) + event->header_size;
6962 header->misc |= perf_misc_flags(regs);
6964 __perf_event_header__init_id(header, data, event);
6966 if (sample_type & PERF_SAMPLE_IP)
6967 data->ip = perf_instruction_pointer(regs);
6969 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6972 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6973 data->callchain = perf_callchain(event, regs);
6975 size += data->callchain->nr;
6977 header->size += size * sizeof(u64);
6980 if (sample_type & PERF_SAMPLE_RAW) {
6981 struct perf_raw_record *raw = data->raw;
6985 struct perf_raw_frag *frag = &raw->frag;
6990 if (perf_raw_frag_last(frag))
6995 size = round_up(sum + sizeof(u32), sizeof(u64));
6996 raw->size = size - sizeof(u32);
6997 frag->pad = raw->size - sum;
7002 header->size += size;
7005 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7006 int size = sizeof(u64); /* nr */
7007 if (data->br_stack) {
7008 if (perf_sample_save_hw_index(event))
7009 size += sizeof(u64);
7011 size += data->br_stack->nr
7012 * sizeof(struct perf_branch_entry);
7014 header->size += size;
7017 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
7018 perf_sample_regs_user(&data->regs_user, regs,
7019 &data->regs_user_copy);
7021 if (sample_type & PERF_SAMPLE_REGS_USER) {
7022 /* regs dump ABI info */
7023 int size = sizeof(u64);
7025 if (data->regs_user.regs) {
7026 u64 mask = event->attr.sample_regs_user;
7027 size += hweight64(mask) * sizeof(u64);
7030 header->size += size;
7033 if (sample_type & PERF_SAMPLE_STACK_USER) {
7035 * Either we need PERF_SAMPLE_STACK_USER bit to be always
7036 * processed as the last one or have additional check added
7037 * in case new sample type is added, because we could eat
7038 * up the rest of the sample size.
7040 u16 stack_size = event->attr.sample_stack_user;
7041 u16 size = sizeof(u64);
7043 stack_size = perf_sample_ustack_size(stack_size, header->size,
7044 data->regs_user.regs);
7047 * If there is something to dump, add space for the dump
7048 * itself and for the field that tells the dynamic size,
7049 * which is how many have been actually dumped.
7052 size += sizeof(u64) + stack_size;
7054 data->stack_user_size = stack_size;
7055 header->size += size;
7058 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7059 /* regs dump ABI info */
7060 int size = sizeof(u64);
7062 perf_sample_regs_intr(&data->regs_intr, regs);
7064 if (data->regs_intr.regs) {
7065 u64 mask = event->attr.sample_regs_intr;
7067 size += hweight64(mask) * sizeof(u64);
7070 header->size += size;
7073 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7074 data->phys_addr = perf_virt_to_phys(data->addr);
7076 #ifdef CONFIG_CGROUP_PERF
7077 if (sample_type & PERF_SAMPLE_CGROUP) {
7078 struct cgroup *cgrp;
7080 /* protected by RCU */
7081 cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup;
7082 data->cgroup = cgroup_id(cgrp);
7086 if (sample_type & PERF_SAMPLE_AUX) {
7089 header->size += sizeof(u64); /* size */
7092 * Given the 16bit nature of header::size, an AUX sample can
7093 * easily overflow it, what with all the preceding sample bits.
7094 * Make sure this doesn't happen by using up to U16_MAX bytes
7095 * per sample in total (rounded down to 8 byte boundary).
7097 size = min_t(size_t, U16_MAX - header->size,
7098 event->attr.aux_sample_size);
7099 size = rounddown(size, 8);
7100 size = perf_prepare_sample_aux(event, data, size);
7102 WARN_ON_ONCE(size + header->size > U16_MAX);
7103 header->size += size;
7106 * If you're adding more sample types here, you likely need to do
7107 * something about the overflowing header::size, like repurpose the
7108 * lowest 3 bits of size, which should be always zero at the moment.
7109 * This raises a more important question, do we really need 512k sized
7110 * samples and why, so good argumentation is in order for whatever you
7113 WARN_ON_ONCE(header->size & 7);
7116 static __always_inline int
7117 __perf_event_output(struct perf_event *event,
7118 struct perf_sample_data *data,
7119 struct pt_regs *regs,
7120 int (*output_begin)(struct perf_output_handle *,
7121 struct perf_event *,
7124 struct perf_output_handle handle;
7125 struct perf_event_header header;
7128 /* protect the callchain buffers */
7131 perf_prepare_sample(&header, data, event, regs);
7133 err = output_begin(&handle, event, header.size);
7137 perf_output_sample(&handle, &header, data, event);
7139 perf_output_end(&handle);
7147 perf_event_output_forward(struct perf_event *event,
7148 struct perf_sample_data *data,
7149 struct pt_regs *regs)
7151 __perf_event_output(event, data, regs, perf_output_begin_forward);
7155 perf_event_output_backward(struct perf_event *event,
7156 struct perf_sample_data *data,
7157 struct pt_regs *regs)
7159 __perf_event_output(event, data, regs, perf_output_begin_backward);
7163 perf_event_output(struct perf_event *event,
7164 struct perf_sample_data *data,
7165 struct pt_regs *regs)
7167 return __perf_event_output(event, data, regs, perf_output_begin);
7174 struct perf_read_event {
7175 struct perf_event_header header;
7182 perf_event_read_event(struct perf_event *event,
7183 struct task_struct *task)
7185 struct perf_output_handle handle;
7186 struct perf_sample_data sample;
7187 struct perf_read_event read_event = {
7189 .type = PERF_RECORD_READ,
7191 .size = sizeof(read_event) + event->read_size,
7193 .pid = perf_event_pid(event, task),
7194 .tid = perf_event_tid(event, task),
7198 perf_event_header__init_id(&read_event.header, &sample, event);
7199 ret = perf_output_begin(&handle, event, read_event.header.size);
7203 perf_output_put(&handle, read_event);
7204 perf_output_read(&handle, event);
7205 perf_event__output_id_sample(event, &handle, &sample);
7207 perf_output_end(&handle);
7210 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
7213 perf_iterate_ctx(struct perf_event_context *ctx,
7214 perf_iterate_f output,
7215 void *data, bool all)
7217 struct perf_event *event;
7219 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7221 if (event->state < PERF_EVENT_STATE_INACTIVE)
7223 if (!event_filter_match(event))
7227 output(event, data);
7231 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
7233 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
7234 struct perf_event *event;
7236 list_for_each_entry_rcu(event, &pel->list, sb_list) {
7238 * Skip events that are not fully formed yet; ensure that
7239 * if we observe event->ctx, both event and ctx will be
7240 * complete enough. See perf_install_in_context().
7242 if (!smp_load_acquire(&event->ctx))
7245 if (event->state < PERF_EVENT_STATE_INACTIVE)
7247 if (!event_filter_match(event))
7249 output(event, data);
7254 * Iterate all events that need to receive side-band events.
7256 * For new callers; ensure that account_pmu_sb_event() includes
7257 * your event, otherwise it might not get delivered.
7260 perf_iterate_sb(perf_iterate_f output, void *data,
7261 struct perf_event_context *task_ctx)
7263 struct perf_event_context *ctx;
7270 * If we have task_ctx != NULL we only notify the task context itself.
7271 * The task_ctx is set only for EXIT events before releasing task
7275 perf_iterate_ctx(task_ctx, output, data, false);
7279 perf_iterate_sb_cpu(output, data);
7281 for_each_task_context_nr(ctxn) {
7282 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7284 perf_iterate_ctx(ctx, output, data, false);
7292 * Clear all file-based filters at exec, they'll have to be
7293 * re-instated when/if these objects are mmapped again.
7295 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
7297 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7298 struct perf_addr_filter *filter;
7299 unsigned int restart = 0, count = 0;
7300 unsigned long flags;
7302 if (!has_addr_filter(event))
7305 raw_spin_lock_irqsave(&ifh->lock, flags);
7306 list_for_each_entry(filter, &ifh->list, entry) {
7307 if (filter->path.dentry) {
7308 event->addr_filter_ranges[count].start = 0;
7309 event->addr_filter_ranges[count].size = 0;
7317 event->addr_filters_gen++;
7318 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7321 perf_event_stop(event, 1);
7324 void perf_event_exec(void)
7326 struct perf_event_context *ctx;
7330 for_each_task_context_nr(ctxn) {
7331 ctx = current->perf_event_ctxp[ctxn];
7335 perf_event_enable_on_exec(ctxn);
7337 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
7343 struct remote_output {
7344 struct perf_buffer *rb;
7348 static void __perf_event_output_stop(struct perf_event *event, void *data)
7350 struct perf_event *parent = event->parent;
7351 struct remote_output *ro = data;
7352 struct perf_buffer *rb = ro->rb;
7353 struct stop_event_data sd = {
7357 if (!has_aux(event))
7364 * In case of inheritance, it will be the parent that links to the
7365 * ring-buffer, but it will be the child that's actually using it.
7367 * We are using event::rb to determine if the event should be stopped,
7368 * however this may race with ring_buffer_attach() (through set_output),
7369 * which will make us skip the event that actually needs to be stopped.
7370 * So ring_buffer_attach() has to stop an aux event before re-assigning
7373 if (rcu_dereference(parent->rb) == rb)
7374 ro->err = __perf_event_stop(&sd);
7377 static int __perf_pmu_output_stop(void *info)
7379 struct perf_event *event = info;
7380 struct pmu *pmu = event->ctx->pmu;
7381 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
7382 struct remote_output ro = {
7387 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
7388 if (cpuctx->task_ctx)
7389 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
7396 static void perf_pmu_output_stop(struct perf_event *event)
7398 struct perf_event *iter;
7403 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
7405 * For per-CPU events, we need to make sure that neither they
7406 * nor their children are running; for cpu==-1 events it's
7407 * sufficient to stop the event itself if it's active, since
7408 * it can't have children.
7412 cpu = READ_ONCE(iter->oncpu);
7417 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
7418 if (err == -EAGAIN) {
7427 * task tracking -- fork/exit
7429 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
7432 struct perf_task_event {
7433 struct task_struct *task;
7434 struct perf_event_context *task_ctx;
7437 struct perf_event_header header;
7447 static int perf_event_task_match(struct perf_event *event)
7449 return event->attr.comm || event->attr.mmap ||
7450 event->attr.mmap2 || event->attr.mmap_data ||
7454 static void perf_event_task_output(struct perf_event *event,
7457 struct perf_task_event *task_event = data;
7458 struct perf_output_handle handle;
7459 struct perf_sample_data sample;
7460 struct task_struct *task = task_event->task;
7461 int ret, size = task_event->event_id.header.size;
7463 if (!perf_event_task_match(event))
7466 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
7468 ret = perf_output_begin(&handle, event,
7469 task_event->event_id.header.size);
7473 task_event->event_id.pid = perf_event_pid(event, task);
7474 task_event->event_id.ppid = perf_event_pid(event, current);
7476 task_event->event_id.tid = perf_event_tid(event, task);
7477 task_event->event_id.ptid = perf_event_tid(event, current);
7479 task_event->event_id.time = perf_event_clock(event);
7481 perf_output_put(&handle, task_event->event_id);
7483 perf_event__output_id_sample(event, &handle, &sample);
7485 perf_output_end(&handle);
7487 task_event->event_id.header.size = size;
7490 static void perf_event_task(struct task_struct *task,
7491 struct perf_event_context *task_ctx,
7494 struct perf_task_event task_event;
7496 if (!atomic_read(&nr_comm_events) &&
7497 !atomic_read(&nr_mmap_events) &&
7498 !atomic_read(&nr_task_events))
7501 task_event = (struct perf_task_event){
7503 .task_ctx = task_ctx,
7506 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7508 .size = sizeof(task_event.event_id),
7518 perf_iterate_sb(perf_event_task_output,
7523 void perf_event_fork(struct task_struct *task)
7525 perf_event_task(task, NULL, 1);
7526 perf_event_namespaces(task);
7533 struct perf_comm_event {
7534 struct task_struct *task;
7539 struct perf_event_header header;
7546 static int perf_event_comm_match(struct perf_event *event)
7548 return event->attr.comm;
7551 static void perf_event_comm_output(struct perf_event *event,
7554 struct perf_comm_event *comm_event = data;
7555 struct perf_output_handle handle;
7556 struct perf_sample_data sample;
7557 int size = comm_event->event_id.header.size;
7560 if (!perf_event_comm_match(event))
7563 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7564 ret = perf_output_begin(&handle, event,
7565 comm_event->event_id.header.size);
7570 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7571 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7573 perf_output_put(&handle, comm_event->event_id);
7574 __output_copy(&handle, comm_event->comm,
7575 comm_event->comm_size);
7577 perf_event__output_id_sample(event, &handle, &sample);
7579 perf_output_end(&handle);
7581 comm_event->event_id.header.size = size;
7584 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7586 char comm[TASK_COMM_LEN];
7589 memset(comm, 0, sizeof(comm));
7590 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7591 size = ALIGN(strlen(comm)+1, sizeof(u64));
7593 comm_event->comm = comm;
7594 comm_event->comm_size = size;
7596 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7598 perf_iterate_sb(perf_event_comm_output,
7603 void perf_event_comm(struct task_struct *task, bool exec)
7605 struct perf_comm_event comm_event;
7607 if (!atomic_read(&nr_comm_events))
7610 comm_event = (struct perf_comm_event){
7616 .type = PERF_RECORD_COMM,
7617 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7625 perf_event_comm_event(&comm_event);
7629 * namespaces tracking
7632 struct perf_namespaces_event {
7633 struct task_struct *task;
7636 struct perf_event_header header;
7641 struct perf_ns_link_info link_info[NR_NAMESPACES];
7645 static int perf_event_namespaces_match(struct perf_event *event)
7647 return event->attr.namespaces;
7650 static void perf_event_namespaces_output(struct perf_event *event,
7653 struct perf_namespaces_event *namespaces_event = data;
7654 struct perf_output_handle handle;
7655 struct perf_sample_data sample;
7656 u16 header_size = namespaces_event->event_id.header.size;
7659 if (!perf_event_namespaces_match(event))
7662 perf_event_header__init_id(&namespaces_event->event_id.header,
7664 ret = perf_output_begin(&handle, event,
7665 namespaces_event->event_id.header.size);
7669 namespaces_event->event_id.pid = perf_event_pid(event,
7670 namespaces_event->task);
7671 namespaces_event->event_id.tid = perf_event_tid(event,
7672 namespaces_event->task);
7674 perf_output_put(&handle, namespaces_event->event_id);
7676 perf_event__output_id_sample(event, &handle, &sample);
7678 perf_output_end(&handle);
7680 namespaces_event->event_id.header.size = header_size;
7683 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7684 struct task_struct *task,
7685 const struct proc_ns_operations *ns_ops)
7687 struct path ns_path;
7688 struct inode *ns_inode;
7691 error = ns_get_path(&ns_path, task, ns_ops);
7693 ns_inode = ns_path.dentry->d_inode;
7694 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7695 ns_link_info->ino = ns_inode->i_ino;
7700 void perf_event_namespaces(struct task_struct *task)
7702 struct perf_namespaces_event namespaces_event;
7703 struct perf_ns_link_info *ns_link_info;
7705 if (!atomic_read(&nr_namespaces_events))
7708 namespaces_event = (struct perf_namespaces_event){
7712 .type = PERF_RECORD_NAMESPACES,
7714 .size = sizeof(namespaces_event.event_id),
7718 .nr_namespaces = NR_NAMESPACES,
7719 /* .link_info[NR_NAMESPACES] */
7723 ns_link_info = namespaces_event.event_id.link_info;
7725 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7726 task, &mntns_operations);
7728 #ifdef CONFIG_USER_NS
7729 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7730 task, &userns_operations);
7732 #ifdef CONFIG_NET_NS
7733 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7734 task, &netns_operations);
7736 #ifdef CONFIG_UTS_NS
7737 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7738 task, &utsns_operations);
7740 #ifdef CONFIG_IPC_NS
7741 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7742 task, &ipcns_operations);
7744 #ifdef CONFIG_PID_NS
7745 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7746 task, &pidns_operations);
7748 #ifdef CONFIG_CGROUPS
7749 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7750 task, &cgroupns_operations);
7753 perf_iterate_sb(perf_event_namespaces_output,
7761 #ifdef CONFIG_CGROUP_PERF
7763 struct perf_cgroup_event {
7767 struct perf_event_header header;
7773 static int perf_event_cgroup_match(struct perf_event *event)
7775 return event->attr.cgroup;
7778 static void perf_event_cgroup_output(struct perf_event *event, void *data)
7780 struct perf_cgroup_event *cgroup_event = data;
7781 struct perf_output_handle handle;
7782 struct perf_sample_data sample;
7783 u16 header_size = cgroup_event->event_id.header.size;
7786 if (!perf_event_cgroup_match(event))
7789 perf_event_header__init_id(&cgroup_event->event_id.header,
7791 ret = perf_output_begin(&handle, event,
7792 cgroup_event->event_id.header.size);
7796 perf_output_put(&handle, cgroup_event->event_id);
7797 __output_copy(&handle, cgroup_event->path, cgroup_event->path_size);
7799 perf_event__output_id_sample(event, &handle, &sample);
7801 perf_output_end(&handle);
7803 cgroup_event->event_id.header.size = header_size;
7806 static void perf_event_cgroup(struct cgroup *cgrp)
7808 struct perf_cgroup_event cgroup_event;
7809 char path_enomem[16] = "//enomem";
7813 if (!atomic_read(&nr_cgroup_events))
7816 cgroup_event = (struct perf_cgroup_event){
7819 .type = PERF_RECORD_CGROUP,
7821 .size = sizeof(cgroup_event.event_id),
7823 .id = cgroup_id(cgrp),
7827 pathname = kmalloc(PATH_MAX, GFP_KERNEL);
7828 if (pathname == NULL) {
7829 cgroup_event.path = path_enomem;
7831 /* just to be sure to have enough space for alignment */
7832 cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64));
7833 cgroup_event.path = pathname;
7837 * Since our buffer works in 8 byte units we need to align our string
7838 * size to a multiple of 8. However, we must guarantee the tail end is
7839 * zero'd out to avoid leaking random bits to userspace.
7841 size = strlen(cgroup_event.path) + 1;
7842 while (!IS_ALIGNED(size, sizeof(u64)))
7843 cgroup_event.path[size++] = '\0';
7845 cgroup_event.event_id.header.size += size;
7846 cgroup_event.path_size = size;
7848 perf_iterate_sb(perf_event_cgroup_output,
7861 struct perf_mmap_event {
7862 struct vm_area_struct *vma;
7864 const char *file_name;
7872 struct perf_event_header header;
7882 static int perf_event_mmap_match(struct perf_event *event,
7885 struct perf_mmap_event *mmap_event = data;
7886 struct vm_area_struct *vma = mmap_event->vma;
7887 int executable = vma->vm_flags & VM_EXEC;
7889 return (!executable && event->attr.mmap_data) ||
7890 (executable && (event->attr.mmap || event->attr.mmap2));
7893 static void perf_event_mmap_output(struct perf_event *event,
7896 struct perf_mmap_event *mmap_event = data;
7897 struct perf_output_handle handle;
7898 struct perf_sample_data sample;
7899 int size = mmap_event->event_id.header.size;
7900 u32 type = mmap_event->event_id.header.type;
7903 if (!perf_event_mmap_match(event, data))
7906 if (event->attr.mmap2) {
7907 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7908 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7909 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7910 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7911 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7912 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7913 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7916 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7917 ret = perf_output_begin(&handle, event,
7918 mmap_event->event_id.header.size);
7922 mmap_event->event_id.pid = perf_event_pid(event, current);
7923 mmap_event->event_id.tid = perf_event_tid(event, current);
7925 perf_output_put(&handle, mmap_event->event_id);
7927 if (event->attr.mmap2) {
7928 perf_output_put(&handle, mmap_event->maj);
7929 perf_output_put(&handle, mmap_event->min);
7930 perf_output_put(&handle, mmap_event->ino);
7931 perf_output_put(&handle, mmap_event->ino_generation);
7932 perf_output_put(&handle, mmap_event->prot);
7933 perf_output_put(&handle, mmap_event->flags);
7936 __output_copy(&handle, mmap_event->file_name,
7937 mmap_event->file_size);
7939 perf_event__output_id_sample(event, &handle, &sample);
7941 perf_output_end(&handle);
7943 mmap_event->event_id.header.size = size;
7944 mmap_event->event_id.header.type = type;
7947 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7949 struct vm_area_struct *vma = mmap_event->vma;
7950 struct file *file = vma->vm_file;
7951 int maj = 0, min = 0;
7952 u64 ino = 0, gen = 0;
7953 u32 prot = 0, flags = 0;
7959 if (vma->vm_flags & VM_READ)
7961 if (vma->vm_flags & VM_WRITE)
7963 if (vma->vm_flags & VM_EXEC)
7966 if (vma->vm_flags & VM_MAYSHARE)
7969 flags = MAP_PRIVATE;
7971 if (vma->vm_flags & VM_DENYWRITE)
7972 flags |= MAP_DENYWRITE;
7973 if (vma->vm_flags & VM_MAYEXEC)
7974 flags |= MAP_EXECUTABLE;
7975 if (vma->vm_flags & VM_LOCKED)
7976 flags |= MAP_LOCKED;
7977 if (is_vm_hugetlb_page(vma))
7978 flags |= MAP_HUGETLB;
7981 struct inode *inode;
7984 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7990 * d_path() works from the end of the rb backwards, so we
7991 * need to add enough zero bytes after the string to handle
7992 * the 64bit alignment we do later.
7994 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7999 inode = file_inode(vma->vm_file);
8000 dev = inode->i_sb->s_dev;
8002 gen = inode->i_generation;
8008 if (vma->vm_ops && vma->vm_ops->name) {
8009 name = (char *) vma->vm_ops->name(vma);
8014 name = (char *)arch_vma_name(vma);
8018 if (vma->vm_start <= vma->vm_mm->start_brk &&
8019 vma->vm_end >= vma->vm_mm->brk) {
8023 if (vma->vm_start <= vma->vm_mm->start_stack &&
8024 vma->vm_end >= vma->vm_mm->start_stack) {
8034 strlcpy(tmp, name, sizeof(tmp));
8038 * Since our buffer works in 8 byte units we need to align our string
8039 * size to a multiple of 8. However, we must guarantee the tail end is
8040 * zero'd out to avoid leaking random bits to userspace.
8042 size = strlen(name)+1;
8043 while (!IS_ALIGNED(size, sizeof(u64)))
8044 name[size++] = '\0';
8046 mmap_event->file_name = name;
8047 mmap_event->file_size = size;
8048 mmap_event->maj = maj;
8049 mmap_event->min = min;
8050 mmap_event->ino = ino;
8051 mmap_event->ino_generation = gen;
8052 mmap_event->prot = prot;
8053 mmap_event->flags = flags;
8055 if (!(vma->vm_flags & VM_EXEC))
8056 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
8058 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
8060 perf_iterate_sb(perf_event_mmap_output,
8068 * Check whether inode and address range match filter criteria.
8070 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
8071 struct file *file, unsigned long offset,
8074 /* d_inode(NULL) won't be equal to any mapped user-space file */
8075 if (!filter->path.dentry)
8078 if (d_inode(filter->path.dentry) != file_inode(file))
8081 if (filter->offset > offset + size)
8084 if (filter->offset + filter->size < offset)
8090 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
8091 struct vm_area_struct *vma,
8092 struct perf_addr_filter_range *fr)
8094 unsigned long vma_size = vma->vm_end - vma->vm_start;
8095 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8096 struct file *file = vma->vm_file;
8098 if (!perf_addr_filter_match(filter, file, off, vma_size))
8101 if (filter->offset < off) {
8102 fr->start = vma->vm_start;
8103 fr->size = min(vma_size, filter->size - (off - filter->offset));
8105 fr->start = vma->vm_start + filter->offset - off;
8106 fr->size = min(vma->vm_end - fr->start, filter->size);
8112 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
8114 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8115 struct vm_area_struct *vma = data;
8116 struct perf_addr_filter *filter;
8117 unsigned int restart = 0, count = 0;
8118 unsigned long flags;
8120 if (!has_addr_filter(event))
8126 raw_spin_lock_irqsave(&ifh->lock, flags);
8127 list_for_each_entry(filter, &ifh->list, entry) {
8128 if (perf_addr_filter_vma_adjust(filter, vma,
8129 &event->addr_filter_ranges[count]))
8136 event->addr_filters_gen++;
8137 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8140 perf_event_stop(event, 1);
8144 * Adjust all task's events' filters to the new vma
8146 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
8148 struct perf_event_context *ctx;
8152 * Data tracing isn't supported yet and as such there is no need
8153 * to keep track of anything that isn't related to executable code:
8155 if (!(vma->vm_flags & VM_EXEC))
8159 for_each_task_context_nr(ctxn) {
8160 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
8164 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
8169 void perf_event_mmap(struct vm_area_struct *vma)
8171 struct perf_mmap_event mmap_event;
8173 if (!atomic_read(&nr_mmap_events))
8176 mmap_event = (struct perf_mmap_event){
8182 .type = PERF_RECORD_MMAP,
8183 .misc = PERF_RECORD_MISC_USER,
8188 .start = vma->vm_start,
8189 .len = vma->vm_end - vma->vm_start,
8190 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
8192 /* .maj (attr_mmap2 only) */
8193 /* .min (attr_mmap2 only) */
8194 /* .ino (attr_mmap2 only) */
8195 /* .ino_generation (attr_mmap2 only) */
8196 /* .prot (attr_mmap2 only) */
8197 /* .flags (attr_mmap2 only) */
8200 perf_addr_filters_adjust(vma);
8201 perf_event_mmap_event(&mmap_event);
8204 void perf_event_aux_event(struct perf_event *event, unsigned long head,
8205 unsigned long size, u64 flags)
8207 struct perf_output_handle handle;
8208 struct perf_sample_data sample;
8209 struct perf_aux_event {
8210 struct perf_event_header header;
8216 .type = PERF_RECORD_AUX,
8218 .size = sizeof(rec),
8226 perf_event_header__init_id(&rec.header, &sample, event);
8227 ret = perf_output_begin(&handle, event, rec.header.size);
8232 perf_output_put(&handle, rec);
8233 perf_event__output_id_sample(event, &handle, &sample);
8235 perf_output_end(&handle);
8239 * Lost/dropped samples logging
8241 void perf_log_lost_samples(struct perf_event *event, u64 lost)
8243 struct perf_output_handle handle;
8244 struct perf_sample_data sample;
8248 struct perf_event_header header;
8250 } lost_samples_event = {
8252 .type = PERF_RECORD_LOST_SAMPLES,
8254 .size = sizeof(lost_samples_event),
8259 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
8261 ret = perf_output_begin(&handle, event,
8262 lost_samples_event.header.size);
8266 perf_output_put(&handle, lost_samples_event);
8267 perf_event__output_id_sample(event, &handle, &sample);
8268 perf_output_end(&handle);
8272 * context_switch tracking
8275 struct perf_switch_event {
8276 struct task_struct *task;
8277 struct task_struct *next_prev;
8280 struct perf_event_header header;
8286 static int perf_event_switch_match(struct perf_event *event)
8288 return event->attr.context_switch;
8291 static void perf_event_switch_output(struct perf_event *event, void *data)
8293 struct perf_switch_event *se = data;
8294 struct perf_output_handle handle;
8295 struct perf_sample_data sample;
8298 if (!perf_event_switch_match(event))
8301 /* Only CPU-wide events are allowed to see next/prev pid/tid */
8302 if (event->ctx->task) {
8303 se->event_id.header.type = PERF_RECORD_SWITCH;
8304 se->event_id.header.size = sizeof(se->event_id.header);
8306 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
8307 se->event_id.header.size = sizeof(se->event_id);
8308 se->event_id.next_prev_pid =
8309 perf_event_pid(event, se->next_prev);
8310 se->event_id.next_prev_tid =
8311 perf_event_tid(event, se->next_prev);
8314 perf_event_header__init_id(&se->event_id.header, &sample, event);
8316 ret = perf_output_begin(&handle, event, se->event_id.header.size);
8320 if (event->ctx->task)
8321 perf_output_put(&handle, se->event_id.header);
8323 perf_output_put(&handle, se->event_id);
8325 perf_event__output_id_sample(event, &handle, &sample);
8327 perf_output_end(&handle);
8330 static void perf_event_switch(struct task_struct *task,
8331 struct task_struct *next_prev, bool sched_in)
8333 struct perf_switch_event switch_event;
8335 /* N.B. caller checks nr_switch_events != 0 */
8337 switch_event = (struct perf_switch_event){
8339 .next_prev = next_prev,
8343 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
8346 /* .next_prev_pid */
8347 /* .next_prev_tid */
8351 if (!sched_in && task->state == TASK_RUNNING)
8352 switch_event.event_id.header.misc |=
8353 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
8355 perf_iterate_sb(perf_event_switch_output,
8361 * IRQ throttle logging
8364 static void perf_log_throttle(struct perf_event *event, int enable)
8366 struct perf_output_handle handle;
8367 struct perf_sample_data sample;
8371 struct perf_event_header header;
8375 } throttle_event = {
8377 .type = PERF_RECORD_THROTTLE,
8379 .size = sizeof(throttle_event),
8381 .time = perf_event_clock(event),
8382 .id = primary_event_id(event),
8383 .stream_id = event->id,
8387 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
8389 perf_event_header__init_id(&throttle_event.header, &sample, event);
8391 ret = perf_output_begin(&handle, event,
8392 throttle_event.header.size);
8396 perf_output_put(&handle, throttle_event);
8397 perf_event__output_id_sample(event, &handle, &sample);
8398 perf_output_end(&handle);
8402 * ksymbol register/unregister tracking
8405 struct perf_ksymbol_event {
8409 struct perf_event_header header;
8417 static int perf_event_ksymbol_match(struct perf_event *event)
8419 return event->attr.ksymbol;
8422 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
8424 struct perf_ksymbol_event *ksymbol_event = data;
8425 struct perf_output_handle handle;
8426 struct perf_sample_data sample;
8429 if (!perf_event_ksymbol_match(event))
8432 perf_event_header__init_id(&ksymbol_event->event_id.header,
8434 ret = perf_output_begin(&handle, event,
8435 ksymbol_event->event_id.header.size);
8439 perf_output_put(&handle, ksymbol_event->event_id);
8440 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
8441 perf_event__output_id_sample(event, &handle, &sample);
8443 perf_output_end(&handle);
8446 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
8449 struct perf_ksymbol_event ksymbol_event;
8450 char name[KSYM_NAME_LEN];
8454 if (!atomic_read(&nr_ksymbol_events))
8457 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
8458 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
8461 strlcpy(name, sym, KSYM_NAME_LEN);
8462 name_len = strlen(name) + 1;
8463 while (!IS_ALIGNED(name_len, sizeof(u64)))
8464 name[name_len++] = '\0';
8465 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
8468 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
8470 ksymbol_event = (struct perf_ksymbol_event){
8472 .name_len = name_len,
8475 .type = PERF_RECORD_KSYMBOL,
8476 .size = sizeof(ksymbol_event.event_id) +
8481 .ksym_type = ksym_type,
8486 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
8489 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
8493 * bpf program load/unload tracking
8496 struct perf_bpf_event {
8497 struct bpf_prog *prog;
8499 struct perf_event_header header;
8503 u8 tag[BPF_TAG_SIZE];
8507 static int perf_event_bpf_match(struct perf_event *event)
8509 return event->attr.bpf_event;
8512 static void perf_event_bpf_output(struct perf_event *event, void *data)
8514 struct perf_bpf_event *bpf_event = data;
8515 struct perf_output_handle handle;
8516 struct perf_sample_data sample;
8519 if (!perf_event_bpf_match(event))
8522 perf_event_header__init_id(&bpf_event->event_id.header,
8524 ret = perf_output_begin(&handle, event,
8525 bpf_event->event_id.header.size);
8529 perf_output_put(&handle, bpf_event->event_id);
8530 perf_event__output_id_sample(event, &handle, &sample);
8532 perf_output_end(&handle);
8535 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
8536 enum perf_bpf_event_type type)
8538 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
8541 if (prog->aux->func_cnt == 0) {
8542 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
8543 (u64)(unsigned long)prog->bpf_func,
8544 prog->jited_len, unregister,
8545 prog->aux->ksym.name);
8547 for (i = 0; i < prog->aux->func_cnt; i++) {
8548 struct bpf_prog *subprog = prog->aux->func[i];
8551 PERF_RECORD_KSYMBOL_TYPE_BPF,
8552 (u64)(unsigned long)subprog->bpf_func,
8553 subprog->jited_len, unregister,
8554 prog->aux->ksym.name);
8559 void perf_event_bpf_event(struct bpf_prog *prog,
8560 enum perf_bpf_event_type type,
8563 struct perf_bpf_event bpf_event;
8565 if (type <= PERF_BPF_EVENT_UNKNOWN ||
8566 type >= PERF_BPF_EVENT_MAX)
8570 case PERF_BPF_EVENT_PROG_LOAD:
8571 case PERF_BPF_EVENT_PROG_UNLOAD:
8572 if (atomic_read(&nr_ksymbol_events))
8573 perf_event_bpf_emit_ksymbols(prog, type);
8579 if (!atomic_read(&nr_bpf_events))
8582 bpf_event = (struct perf_bpf_event){
8586 .type = PERF_RECORD_BPF_EVENT,
8587 .size = sizeof(bpf_event.event_id),
8591 .id = prog->aux->id,
8595 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
8597 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
8598 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
8601 void perf_event_itrace_started(struct perf_event *event)
8603 event->attach_state |= PERF_ATTACH_ITRACE;
8606 static void perf_log_itrace_start(struct perf_event *event)
8608 struct perf_output_handle handle;
8609 struct perf_sample_data sample;
8610 struct perf_aux_event {
8611 struct perf_event_header header;
8618 event = event->parent;
8620 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
8621 event->attach_state & PERF_ATTACH_ITRACE)
8624 rec.header.type = PERF_RECORD_ITRACE_START;
8625 rec.header.misc = 0;
8626 rec.header.size = sizeof(rec);
8627 rec.pid = perf_event_pid(event, current);
8628 rec.tid = perf_event_tid(event, current);
8630 perf_event_header__init_id(&rec.header, &sample, event);
8631 ret = perf_output_begin(&handle, event, rec.header.size);
8636 perf_output_put(&handle, rec);
8637 perf_event__output_id_sample(event, &handle, &sample);
8639 perf_output_end(&handle);
8643 __perf_event_account_interrupt(struct perf_event *event, int throttle)
8645 struct hw_perf_event *hwc = &event->hw;
8649 seq = __this_cpu_read(perf_throttled_seq);
8650 if (seq != hwc->interrupts_seq) {
8651 hwc->interrupts_seq = seq;
8652 hwc->interrupts = 1;
8655 if (unlikely(throttle
8656 && hwc->interrupts >= max_samples_per_tick)) {
8657 __this_cpu_inc(perf_throttled_count);
8658 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
8659 hwc->interrupts = MAX_INTERRUPTS;
8660 perf_log_throttle(event, 0);
8665 if (event->attr.freq) {
8666 u64 now = perf_clock();
8667 s64 delta = now - hwc->freq_time_stamp;
8669 hwc->freq_time_stamp = now;
8671 if (delta > 0 && delta < 2*TICK_NSEC)
8672 perf_adjust_period(event, delta, hwc->last_period, true);
8678 int perf_event_account_interrupt(struct perf_event *event)
8680 return __perf_event_account_interrupt(event, 1);
8684 * Generic event overflow handling, sampling.
8687 static int __perf_event_overflow(struct perf_event *event,
8688 int throttle, struct perf_sample_data *data,
8689 struct pt_regs *regs)
8691 int events = atomic_read(&event->event_limit);
8695 * Non-sampling counters might still use the PMI to fold short
8696 * hardware counters, ignore those.
8698 if (unlikely(!is_sampling_event(event)))
8701 ret = __perf_event_account_interrupt(event, throttle);
8704 * XXX event_limit might not quite work as expected on inherited
8708 event->pending_kill = POLL_IN;
8709 if (events && atomic_dec_and_test(&event->event_limit)) {
8711 event->pending_kill = POLL_HUP;
8713 perf_event_disable_inatomic(event);
8716 READ_ONCE(event->overflow_handler)(event, data, regs);
8718 if (*perf_event_fasync(event) && event->pending_kill) {
8719 event->pending_wakeup = 1;
8720 irq_work_queue(&event->pending);
8726 int perf_event_overflow(struct perf_event *event,
8727 struct perf_sample_data *data,
8728 struct pt_regs *regs)
8730 return __perf_event_overflow(event, 1, data, regs);
8734 * Generic software event infrastructure
8737 struct swevent_htable {
8738 struct swevent_hlist *swevent_hlist;
8739 struct mutex hlist_mutex;
8742 /* Recursion avoidance in each contexts */
8743 int recursion[PERF_NR_CONTEXTS];
8746 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
8749 * We directly increment event->count and keep a second value in
8750 * event->hw.period_left to count intervals. This period event
8751 * is kept in the range [-sample_period, 0] so that we can use the
8755 u64 perf_swevent_set_period(struct perf_event *event)
8757 struct hw_perf_event *hwc = &event->hw;
8758 u64 period = hwc->last_period;
8762 hwc->last_period = hwc->sample_period;
8765 old = val = local64_read(&hwc->period_left);
8769 nr = div64_u64(period + val, period);
8770 offset = nr * period;
8772 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
8778 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
8779 struct perf_sample_data *data,
8780 struct pt_regs *regs)
8782 struct hw_perf_event *hwc = &event->hw;
8786 overflow = perf_swevent_set_period(event);
8788 if (hwc->interrupts == MAX_INTERRUPTS)
8791 for (; overflow; overflow--) {
8792 if (__perf_event_overflow(event, throttle,
8795 * We inhibit the overflow from happening when
8796 * hwc->interrupts == MAX_INTERRUPTS.
8804 static void perf_swevent_event(struct perf_event *event, u64 nr,
8805 struct perf_sample_data *data,
8806 struct pt_regs *regs)
8808 struct hw_perf_event *hwc = &event->hw;
8810 local64_add(nr, &event->count);
8815 if (!is_sampling_event(event))
8818 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
8820 return perf_swevent_overflow(event, 1, data, regs);
8822 data->period = event->hw.last_period;
8824 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
8825 return perf_swevent_overflow(event, 1, data, regs);
8827 if (local64_add_negative(nr, &hwc->period_left))
8830 perf_swevent_overflow(event, 0, data, regs);
8833 static int perf_exclude_event(struct perf_event *event,
8834 struct pt_regs *regs)
8836 if (event->hw.state & PERF_HES_STOPPED)
8840 if (event->attr.exclude_user && user_mode(regs))
8843 if (event->attr.exclude_kernel && !user_mode(regs))
8850 static int perf_swevent_match(struct perf_event *event,
8851 enum perf_type_id type,
8853 struct perf_sample_data *data,
8854 struct pt_regs *regs)
8856 if (event->attr.type != type)
8859 if (event->attr.config != event_id)
8862 if (perf_exclude_event(event, regs))
8868 static inline u64 swevent_hash(u64 type, u32 event_id)
8870 u64 val = event_id | (type << 32);
8872 return hash_64(val, SWEVENT_HLIST_BITS);
8875 static inline struct hlist_head *
8876 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
8878 u64 hash = swevent_hash(type, event_id);
8880 return &hlist->heads[hash];
8883 /* For the read side: events when they trigger */
8884 static inline struct hlist_head *
8885 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8887 struct swevent_hlist *hlist;
8889 hlist = rcu_dereference(swhash->swevent_hlist);
8893 return __find_swevent_head(hlist, type, event_id);
8896 /* For the event head insertion and removal in the hlist */
8897 static inline struct hlist_head *
8898 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8900 struct swevent_hlist *hlist;
8901 u32 event_id = event->attr.config;
8902 u64 type = event->attr.type;
8905 * Event scheduling is always serialized against hlist allocation
8906 * and release. Which makes the protected version suitable here.
8907 * The context lock guarantees that.
8909 hlist = rcu_dereference_protected(swhash->swevent_hlist,
8910 lockdep_is_held(&event->ctx->lock));
8914 return __find_swevent_head(hlist, type, event_id);
8917 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8919 struct perf_sample_data *data,
8920 struct pt_regs *regs)
8922 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8923 struct perf_event *event;
8924 struct hlist_head *head;
8927 head = find_swevent_head_rcu(swhash, type, event_id);
8931 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8932 if (perf_swevent_match(event, type, event_id, data, regs))
8933 perf_swevent_event(event, nr, data, regs);
8939 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8941 int perf_swevent_get_recursion_context(void)
8943 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8945 return get_recursion_context(swhash->recursion);
8947 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8949 void perf_swevent_put_recursion_context(int rctx)
8951 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8953 put_recursion_context(swhash->recursion, rctx);
8956 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8958 struct perf_sample_data data;
8960 if (WARN_ON_ONCE(!regs))
8963 perf_sample_data_init(&data, addr, 0);
8964 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8967 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8971 preempt_disable_notrace();
8972 rctx = perf_swevent_get_recursion_context();
8973 if (unlikely(rctx < 0))
8976 ___perf_sw_event(event_id, nr, regs, addr);
8978 perf_swevent_put_recursion_context(rctx);
8980 preempt_enable_notrace();
8983 static void perf_swevent_read(struct perf_event *event)
8987 static int perf_swevent_add(struct perf_event *event, int flags)
8989 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8990 struct hw_perf_event *hwc = &event->hw;
8991 struct hlist_head *head;
8993 if (is_sampling_event(event)) {
8994 hwc->last_period = hwc->sample_period;
8995 perf_swevent_set_period(event);
8998 hwc->state = !(flags & PERF_EF_START);
9000 head = find_swevent_head(swhash, event);
9001 if (WARN_ON_ONCE(!head))
9004 hlist_add_head_rcu(&event->hlist_entry, head);
9005 perf_event_update_userpage(event);
9010 static void perf_swevent_del(struct perf_event *event, int flags)
9012 hlist_del_rcu(&event->hlist_entry);
9015 static void perf_swevent_start(struct perf_event *event, int flags)
9017 event->hw.state = 0;
9020 static void perf_swevent_stop(struct perf_event *event, int flags)
9022 event->hw.state = PERF_HES_STOPPED;
9025 /* Deref the hlist from the update side */
9026 static inline struct swevent_hlist *
9027 swevent_hlist_deref(struct swevent_htable *swhash)
9029 return rcu_dereference_protected(swhash->swevent_hlist,
9030 lockdep_is_held(&swhash->hlist_mutex));
9033 static void swevent_hlist_release(struct swevent_htable *swhash)
9035 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
9040 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
9041 kfree_rcu(hlist, rcu_head);
9044 static void swevent_hlist_put_cpu(int cpu)
9046 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9048 mutex_lock(&swhash->hlist_mutex);
9050 if (!--swhash->hlist_refcount)
9051 swevent_hlist_release(swhash);
9053 mutex_unlock(&swhash->hlist_mutex);
9056 static void swevent_hlist_put(void)
9060 for_each_possible_cpu(cpu)
9061 swevent_hlist_put_cpu(cpu);
9064 static int swevent_hlist_get_cpu(int cpu)
9066 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9069 mutex_lock(&swhash->hlist_mutex);
9070 if (!swevent_hlist_deref(swhash) &&
9071 cpumask_test_cpu(cpu, perf_online_mask)) {
9072 struct swevent_hlist *hlist;
9074 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
9079 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9081 swhash->hlist_refcount++;
9083 mutex_unlock(&swhash->hlist_mutex);
9088 static int swevent_hlist_get(void)
9090 int err, cpu, failed_cpu;
9092 mutex_lock(&pmus_lock);
9093 for_each_possible_cpu(cpu) {
9094 err = swevent_hlist_get_cpu(cpu);
9100 mutex_unlock(&pmus_lock);
9103 for_each_possible_cpu(cpu) {
9104 if (cpu == failed_cpu)
9106 swevent_hlist_put_cpu(cpu);
9108 mutex_unlock(&pmus_lock);
9112 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
9114 static void sw_perf_event_destroy(struct perf_event *event)
9116 u64 event_id = event->attr.config;
9118 WARN_ON(event->parent);
9120 static_key_slow_dec(&perf_swevent_enabled[event_id]);
9121 swevent_hlist_put();
9124 static int perf_swevent_init(struct perf_event *event)
9126 u64 event_id = event->attr.config;
9128 if (event->attr.type != PERF_TYPE_SOFTWARE)
9132 * no branch sampling for software events
9134 if (has_branch_stack(event))
9138 case PERF_COUNT_SW_CPU_CLOCK:
9139 case PERF_COUNT_SW_TASK_CLOCK:
9146 if (event_id >= PERF_COUNT_SW_MAX)
9149 if (!event->parent) {
9152 err = swevent_hlist_get();
9156 static_key_slow_inc(&perf_swevent_enabled[event_id]);
9157 event->destroy = sw_perf_event_destroy;
9163 static struct pmu perf_swevent = {
9164 .task_ctx_nr = perf_sw_context,
9166 .capabilities = PERF_PMU_CAP_NO_NMI,
9168 .event_init = perf_swevent_init,
9169 .add = perf_swevent_add,
9170 .del = perf_swevent_del,
9171 .start = perf_swevent_start,
9172 .stop = perf_swevent_stop,
9173 .read = perf_swevent_read,
9176 #ifdef CONFIG_EVENT_TRACING
9178 static int perf_tp_filter_match(struct perf_event *event,
9179 struct perf_sample_data *data)
9181 void *record = data->raw->frag.data;
9183 /* only top level events have filters set */
9185 event = event->parent;
9187 if (likely(!event->filter) || filter_match_preds(event->filter, record))
9192 static int perf_tp_event_match(struct perf_event *event,
9193 struct perf_sample_data *data,
9194 struct pt_regs *regs)
9196 if (event->hw.state & PERF_HES_STOPPED)
9199 * If exclude_kernel, only trace user-space tracepoints (uprobes)
9201 if (event->attr.exclude_kernel && !user_mode(regs))
9204 if (!perf_tp_filter_match(event, data))
9210 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
9211 struct trace_event_call *call, u64 count,
9212 struct pt_regs *regs, struct hlist_head *head,
9213 struct task_struct *task)
9215 if (bpf_prog_array_valid(call)) {
9216 *(struct pt_regs **)raw_data = regs;
9217 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
9218 perf_swevent_put_recursion_context(rctx);
9222 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
9225 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
9227 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
9228 struct pt_regs *regs, struct hlist_head *head, int rctx,
9229 struct task_struct *task)
9231 struct perf_sample_data data;
9232 struct perf_event *event;
9234 struct perf_raw_record raw = {
9241 perf_sample_data_init(&data, 0, 0);
9244 perf_trace_buf_update(record, event_type);
9246 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9247 if (perf_tp_event_match(event, &data, regs))
9248 perf_swevent_event(event, count, &data, regs);
9252 * If we got specified a target task, also iterate its context and
9253 * deliver this event there too.
9255 if (task && task != current) {
9256 struct perf_event_context *ctx;
9257 struct trace_entry *entry = record;
9260 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
9264 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
9265 if (event->cpu != smp_processor_id())
9267 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9269 if (event->attr.config != entry->type)
9271 if (perf_tp_event_match(event, &data, regs))
9272 perf_swevent_event(event, count, &data, regs);
9278 perf_swevent_put_recursion_context(rctx);
9280 EXPORT_SYMBOL_GPL(perf_tp_event);
9282 static void tp_perf_event_destroy(struct perf_event *event)
9284 perf_trace_destroy(event);
9287 static int perf_tp_event_init(struct perf_event *event)
9291 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9295 * no branch sampling for tracepoint events
9297 if (has_branch_stack(event))
9300 err = perf_trace_init(event);
9304 event->destroy = tp_perf_event_destroy;
9309 static struct pmu perf_tracepoint = {
9310 .task_ctx_nr = perf_sw_context,
9312 .event_init = perf_tp_event_init,
9313 .add = perf_trace_add,
9314 .del = perf_trace_del,
9315 .start = perf_swevent_start,
9316 .stop = perf_swevent_stop,
9317 .read = perf_swevent_read,
9320 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
9322 * Flags in config, used by dynamic PMU kprobe and uprobe
9323 * The flags should match following PMU_FORMAT_ATTR().
9325 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
9326 * if not set, create kprobe/uprobe
9328 * The following values specify a reference counter (or semaphore in the
9329 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
9330 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
9332 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
9333 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
9335 enum perf_probe_config {
9336 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
9337 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
9338 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
9341 PMU_FORMAT_ATTR(retprobe, "config:0");
9344 #ifdef CONFIG_KPROBE_EVENTS
9345 static struct attribute *kprobe_attrs[] = {
9346 &format_attr_retprobe.attr,
9350 static struct attribute_group kprobe_format_group = {
9352 .attrs = kprobe_attrs,
9355 static const struct attribute_group *kprobe_attr_groups[] = {
9356 &kprobe_format_group,
9360 static int perf_kprobe_event_init(struct perf_event *event);
9361 static struct pmu perf_kprobe = {
9362 .task_ctx_nr = perf_sw_context,
9363 .event_init = perf_kprobe_event_init,
9364 .add = perf_trace_add,
9365 .del = perf_trace_del,
9366 .start = perf_swevent_start,
9367 .stop = perf_swevent_stop,
9368 .read = perf_swevent_read,
9369 .attr_groups = kprobe_attr_groups,
9372 static int perf_kprobe_event_init(struct perf_event *event)
9377 if (event->attr.type != perf_kprobe.type)
9380 if (!capable(CAP_SYS_ADMIN))
9384 * no branch sampling for probe events
9386 if (has_branch_stack(event))
9389 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9390 err = perf_kprobe_init(event, is_retprobe);
9394 event->destroy = perf_kprobe_destroy;
9398 #endif /* CONFIG_KPROBE_EVENTS */
9400 #ifdef CONFIG_UPROBE_EVENTS
9401 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
9403 static struct attribute *uprobe_attrs[] = {
9404 &format_attr_retprobe.attr,
9405 &format_attr_ref_ctr_offset.attr,
9409 static struct attribute_group uprobe_format_group = {
9411 .attrs = uprobe_attrs,
9414 static const struct attribute_group *uprobe_attr_groups[] = {
9415 &uprobe_format_group,
9419 static int perf_uprobe_event_init(struct perf_event *event);
9420 static struct pmu perf_uprobe = {
9421 .task_ctx_nr = perf_sw_context,
9422 .event_init = perf_uprobe_event_init,
9423 .add = perf_trace_add,
9424 .del = perf_trace_del,
9425 .start = perf_swevent_start,
9426 .stop = perf_swevent_stop,
9427 .read = perf_swevent_read,
9428 .attr_groups = uprobe_attr_groups,
9431 static int perf_uprobe_event_init(struct perf_event *event)
9434 unsigned long ref_ctr_offset;
9437 if (event->attr.type != perf_uprobe.type)
9440 if (!capable(CAP_SYS_ADMIN))
9444 * no branch sampling for probe events
9446 if (has_branch_stack(event))
9449 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9450 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
9451 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
9455 event->destroy = perf_uprobe_destroy;
9459 #endif /* CONFIG_UPROBE_EVENTS */
9461 static inline void perf_tp_register(void)
9463 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
9464 #ifdef CONFIG_KPROBE_EVENTS
9465 perf_pmu_register(&perf_kprobe, "kprobe", -1);
9467 #ifdef CONFIG_UPROBE_EVENTS
9468 perf_pmu_register(&perf_uprobe, "uprobe", -1);
9472 static void perf_event_free_filter(struct perf_event *event)
9474 ftrace_profile_free_filter(event);
9477 #ifdef CONFIG_BPF_SYSCALL
9478 static void bpf_overflow_handler(struct perf_event *event,
9479 struct perf_sample_data *data,
9480 struct pt_regs *regs)
9482 struct bpf_perf_event_data_kern ctx = {
9488 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
9489 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
9492 ret = BPF_PROG_RUN(event->prog, &ctx);
9495 __this_cpu_dec(bpf_prog_active);
9499 event->orig_overflow_handler(event, data, regs);
9502 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9504 struct bpf_prog *prog;
9506 if (event->overflow_handler_context)
9507 /* hw breakpoint or kernel counter */
9513 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
9515 return PTR_ERR(prog);
9518 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
9519 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
9523 static void perf_event_free_bpf_handler(struct perf_event *event)
9525 struct bpf_prog *prog = event->prog;
9530 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
9535 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9539 static void perf_event_free_bpf_handler(struct perf_event *event)
9545 * returns true if the event is a tracepoint, or a kprobe/upprobe created
9546 * with perf_event_open()
9548 static inline bool perf_event_is_tracing(struct perf_event *event)
9550 if (event->pmu == &perf_tracepoint)
9552 #ifdef CONFIG_KPROBE_EVENTS
9553 if (event->pmu == &perf_kprobe)
9556 #ifdef CONFIG_UPROBE_EVENTS
9557 if (event->pmu == &perf_uprobe)
9563 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9565 bool is_kprobe, is_tracepoint, is_syscall_tp;
9566 struct bpf_prog *prog;
9569 if (!perf_event_is_tracing(event))
9570 return perf_event_set_bpf_handler(event, prog_fd);
9572 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
9573 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
9574 is_syscall_tp = is_syscall_trace_event(event->tp_event);
9575 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
9576 /* bpf programs can only be attached to u/kprobe or tracepoint */
9579 prog = bpf_prog_get(prog_fd);
9581 return PTR_ERR(prog);
9583 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
9584 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
9585 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
9586 /* valid fd, but invalid bpf program type */
9591 /* Kprobe override only works for kprobes, not uprobes. */
9592 if (prog->kprobe_override &&
9593 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
9598 if (is_tracepoint || is_syscall_tp) {
9599 int off = trace_event_get_offsets(event->tp_event);
9601 if (prog->aux->max_ctx_offset > off) {
9607 ret = perf_event_attach_bpf_prog(event, prog);
9613 static void perf_event_free_bpf_prog(struct perf_event *event)
9615 if (!perf_event_is_tracing(event)) {
9616 perf_event_free_bpf_handler(event);
9619 perf_event_detach_bpf_prog(event);
9624 static inline void perf_tp_register(void)
9628 static void perf_event_free_filter(struct perf_event *event)
9632 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9637 static void perf_event_free_bpf_prog(struct perf_event *event)
9640 #endif /* CONFIG_EVENT_TRACING */
9642 #ifdef CONFIG_HAVE_HW_BREAKPOINT
9643 void perf_bp_event(struct perf_event *bp, void *data)
9645 struct perf_sample_data sample;
9646 struct pt_regs *regs = data;
9648 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
9650 if (!bp->hw.state && !perf_exclude_event(bp, regs))
9651 perf_swevent_event(bp, 1, &sample, regs);
9656 * Allocate a new address filter
9658 static struct perf_addr_filter *
9659 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
9661 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
9662 struct perf_addr_filter *filter;
9664 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
9668 INIT_LIST_HEAD(&filter->entry);
9669 list_add_tail(&filter->entry, filters);
9674 static void free_filters_list(struct list_head *filters)
9676 struct perf_addr_filter *filter, *iter;
9678 list_for_each_entry_safe(filter, iter, filters, entry) {
9679 path_put(&filter->path);
9680 list_del(&filter->entry);
9686 * Free existing address filters and optionally install new ones
9688 static void perf_addr_filters_splice(struct perf_event *event,
9689 struct list_head *head)
9691 unsigned long flags;
9694 if (!has_addr_filter(event))
9697 /* don't bother with children, they don't have their own filters */
9701 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
9703 list_splice_init(&event->addr_filters.list, &list);
9705 list_splice(head, &event->addr_filters.list);
9707 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
9709 free_filters_list(&list);
9713 * Scan through mm's vmas and see if one of them matches the
9714 * @filter; if so, adjust filter's address range.
9715 * Called with mm::mmap_sem down for reading.
9717 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
9718 struct mm_struct *mm,
9719 struct perf_addr_filter_range *fr)
9721 struct vm_area_struct *vma;
9723 for (vma = mm->mmap; vma; vma = vma->vm_next) {
9727 if (perf_addr_filter_vma_adjust(filter, vma, fr))
9733 * Update event's address range filters based on the
9734 * task's existing mappings, if any.
9736 static void perf_event_addr_filters_apply(struct perf_event *event)
9738 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
9739 struct task_struct *task = READ_ONCE(event->ctx->task);
9740 struct perf_addr_filter *filter;
9741 struct mm_struct *mm = NULL;
9742 unsigned int count = 0;
9743 unsigned long flags;
9746 * We may observe TASK_TOMBSTONE, which means that the event tear-down
9747 * will stop on the parent's child_mutex that our caller is also holding
9749 if (task == TASK_TOMBSTONE)
9752 if (ifh->nr_file_filters) {
9753 mm = get_task_mm(event->ctx->task);
9757 down_read(&mm->mmap_sem);
9760 raw_spin_lock_irqsave(&ifh->lock, flags);
9761 list_for_each_entry(filter, &ifh->list, entry) {
9762 if (filter->path.dentry) {
9764 * Adjust base offset if the filter is associated to a
9765 * binary that needs to be mapped:
9767 event->addr_filter_ranges[count].start = 0;
9768 event->addr_filter_ranges[count].size = 0;
9770 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
9772 event->addr_filter_ranges[count].start = filter->offset;
9773 event->addr_filter_ranges[count].size = filter->size;
9779 event->addr_filters_gen++;
9780 raw_spin_unlock_irqrestore(&ifh->lock, flags);
9782 if (ifh->nr_file_filters) {
9783 up_read(&mm->mmap_sem);
9789 perf_event_stop(event, 1);
9793 * Address range filtering: limiting the data to certain
9794 * instruction address ranges. Filters are ioctl()ed to us from
9795 * userspace as ascii strings.
9797 * Filter string format:
9800 * where ACTION is one of the
9801 * * "filter": limit the trace to this region
9802 * * "start": start tracing from this address
9803 * * "stop": stop tracing at this address/region;
9805 * * for kernel addresses: <start address>[/<size>]
9806 * * for object files: <start address>[/<size>]@</path/to/object/file>
9808 * if <size> is not specified or is zero, the range is treated as a single
9809 * address; not valid for ACTION=="filter".
9823 IF_STATE_ACTION = 0,
9828 static const match_table_t if_tokens = {
9829 { IF_ACT_FILTER, "filter" },
9830 { IF_ACT_START, "start" },
9831 { IF_ACT_STOP, "stop" },
9832 { IF_SRC_FILE, "%u/%u@%s" },
9833 { IF_SRC_KERNEL, "%u/%u" },
9834 { IF_SRC_FILEADDR, "%u@%s" },
9835 { IF_SRC_KERNELADDR, "%u" },
9836 { IF_ACT_NONE, NULL },
9840 * Address filter string parser
9843 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
9844 struct list_head *filters)
9846 struct perf_addr_filter *filter = NULL;
9847 char *start, *orig, *filename = NULL;
9848 substring_t args[MAX_OPT_ARGS];
9849 int state = IF_STATE_ACTION, token;
9850 unsigned int kernel = 0;
9853 orig = fstr = kstrdup(fstr, GFP_KERNEL);
9857 while ((start = strsep(&fstr, " ,\n")) != NULL) {
9858 static const enum perf_addr_filter_action_t actions[] = {
9859 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
9860 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
9861 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
9868 /* filter definition begins */
9869 if (state == IF_STATE_ACTION) {
9870 filter = perf_addr_filter_new(event, filters);
9875 token = match_token(start, if_tokens, args);
9880 if (state != IF_STATE_ACTION)
9883 filter->action = actions[token];
9884 state = IF_STATE_SOURCE;
9887 case IF_SRC_KERNELADDR:
9892 case IF_SRC_FILEADDR:
9894 if (state != IF_STATE_SOURCE)
9898 ret = kstrtoul(args[0].from, 0, &filter->offset);
9902 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
9904 ret = kstrtoul(args[1].from, 0, &filter->size);
9909 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9910 int fpos = token == IF_SRC_FILE ? 2 : 1;
9912 filename = match_strdup(&args[fpos]);
9919 state = IF_STATE_END;
9927 * Filter definition is fully parsed, validate and install it.
9928 * Make sure that it doesn't contradict itself or the event's
9931 if (state == IF_STATE_END) {
9933 if (kernel && event->attr.exclude_kernel)
9937 * ACTION "filter" must have a non-zero length region
9940 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9949 * For now, we only support file-based filters
9950 * in per-task events; doing so for CPU-wide
9951 * events requires additional context switching
9952 * trickery, since same object code will be
9953 * mapped at different virtual addresses in
9954 * different processes.
9957 if (!event->ctx->task)
9958 goto fail_free_name;
9960 /* look up the path and grab its inode */
9961 ret = kern_path(filename, LOOKUP_FOLLOW,
9964 goto fail_free_name;
9970 if (!filter->path.dentry ||
9971 !S_ISREG(d_inode(filter->path.dentry)
9975 event->addr_filters.nr_file_filters++;
9978 /* ready to consume more filters */
9979 state = IF_STATE_ACTION;
9984 if (state != IF_STATE_ACTION)
9994 free_filters_list(filters);
10001 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
10003 LIST_HEAD(filters);
10007 * Since this is called in perf_ioctl() path, we're already holding
10010 lockdep_assert_held(&event->ctx->mutex);
10012 if (WARN_ON_ONCE(event->parent))
10015 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
10017 goto fail_clear_files;
10019 ret = event->pmu->addr_filters_validate(&filters);
10021 goto fail_free_filters;
10023 /* remove existing filters, if any */
10024 perf_addr_filters_splice(event, &filters);
10026 /* install new filters */
10027 perf_event_for_each_child(event, perf_event_addr_filters_apply);
10032 free_filters_list(&filters);
10035 event->addr_filters.nr_file_filters = 0;
10040 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
10045 filter_str = strndup_user(arg, PAGE_SIZE);
10046 if (IS_ERR(filter_str))
10047 return PTR_ERR(filter_str);
10049 #ifdef CONFIG_EVENT_TRACING
10050 if (perf_event_is_tracing(event)) {
10051 struct perf_event_context *ctx = event->ctx;
10054 * Beware, here be dragons!!
10056 * the tracepoint muck will deadlock against ctx->mutex, but
10057 * the tracepoint stuff does not actually need it. So
10058 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
10059 * already have a reference on ctx.
10061 * This can result in event getting moved to a different ctx,
10062 * but that does not affect the tracepoint state.
10064 mutex_unlock(&ctx->mutex);
10065 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
10066 mutex_lock(&ctx->mutex);
10069 if (has_addr_filter(event))
10070 ret = perf_event_set_addr_filter(event, filter_str);
10077 * hrtimer based swevent callback
10080 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
10082 enum hrtimer_restart ret = HRTIMER_RESTART;
10083 struct perf_sample_data data;
10084 struct pt_regs *regs;
10085 struct perf_event *event;
10088 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
10090 if (event->state != PERF_EVENT_STATE_ACTIVE)
10091 return HRTIMER_NORESTART;
10093 event->pmu->read(event);
10095 perf_sample_data_init(&data, 0, event->hw.last_period);
10096 regs = get_irq_regs();
10098 if (regs && !perf_exclude_event(event, regs)) {
10099 if (!(event->attr.exclude_idle && is_idle_task(current)))
10100 if (__perf_event_overflow(event, 1, &data, regs))
10101 ret = HRTIMER_NORESTART;
10104 period = max_t(u64, 10000, event->hw.sample_period);
10105 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
10110 static void perf_swevent_start_hrtimer(struct perf_event *event)
10112 struct hw_perf_event *hwc = &event->hw;
10115 if (!is_sampling_event(event))
10118 period = local64_read(&hwc->period_left);
10123 local64_set(&hwc->period_left, 0);
10125 period = max_t(u64, 10000, hwc->sample_period);
10127 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
10128 HRTIMER_MODE_REL_PINNED_HARD);
10131 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
10133 struct hw_perf_event *hwc = &event->hw;
10135 if (is_sampling_event(event)) {
10136 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
10137 local64_set(&hwc->period_left, ktime_to_ns(remaining));
10139 hrtimer_cancel(&hwc->hrtimer);
10143 static void perf_swevent_init_hrtimer(struct perf_event *event)
10145 struct hw_perf_event *hwc = &event->hw;
10147 if (!is_sampling_event(event))
10150 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
10151 hwc->hrtimer.function = perf_swevent_hrtimer;
10154 * Since hrtimers have a fixed rate, we can do a static freq->period
10155 * mapping and avoid the whole period adjust feedback stuff.
10157 if (event->attr.freq) {
10158 long freq = event->attr.sample_freq;
10160 event->attr.sample_period = NSEC_PER_SEC / freq;
10161 hwc->sample_period = event->attr.sample_period;
10162 local64_set(&hwc->period_left, hwc->sample_period);
10163 hwc->last_period = hwc->sample_period;
10164 event->attr.freq = 0;
10169 * Software event: cpu wall time clock
10172 static void cpu_clock_event_update(struct perf_event *event)
10177 now = local_clock();
10178 prev = local64_xchg(&event->hw.prev_count, now);
10179 local64_add(now - prev, &event->count);
10182 static void cpu_clock_event_start(struct perf_event *event, int flags)
10184 local64_set(&event->hw.prev_count, local_clock());
10185 perf_swevent_start_hrtimer(event);
10188 static void cpu_clock_event_stop(struct perf_event *event, int flags)
10190 perf_swevent_cancel_hrtimer(event);
10191 cpu_clock_event_update(event);
10194 static int cpu_clock_event_add(struct perf_event *event, int flags)
10196 if (flags & PERF_EF_START)
10197 cpu_clock_event_start(event, flags);
10198 perf_event_update_userpage(event);
10203 static void cpu_clock_event_del(struct perf_event *event, int flags)
10205 cpu_clock_event_stop(event, flags);
10208 static void cpu_clock_event_read(struct perf_event *event)
10210 cpu_clock_event_update(event);
10213 static int cpu_clock_event_init(struct perf_event *event)
10215 if (event->attr.type != PERF_TYPE_SOFTWARE)
10218 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
10222 * no branch sampling for software events
10224 if (has_branch_stack(event))
10225 return -EOPNOTSUPP;
10227 perf_swevent_init_hrtimer(event);
10232 static struct pmu perf_cpu_clock = {
10233 .task_ctx_nr = perf_sw_context,
10235 .capabilities = PERF_PMU_CAP_NO_NMI,
10237 .event_init = cpu_clock_event_init,
10238 .add = cpu_clock_event_add,
10239 .del = cpu_clock_event_del,
10240 .start = cpu_clock_event_start,
10241 .stop = cpu_clock_event_stop,
10242 .read = cpu_clock_event_read,
10246 * Software event: task time clock
10249 static void task_clock_event_update(struct perf_event *event, u64 now)
10254 prev = local64_xchg(&event->hw.prev_count, now);
10255 delta = now - prev;
10256 local64_add(delta, &event->count);
10259 static void task_clock_event_start(struct perf_event *event, int flags)
10261 local64_set(&event->hw.prev_count, event->ctx->time);
10262 perf_swevent_start_hrtimer(event);
10265 static void task_clock_event_stop(struct perf_event *event, int flags)
10267 perf_swevent_cancel_hrtimer(event);
10268 task_clock_event_update(event, event->ctx->time);
10271 static int task_clock_event_add(struct perf_event *event, int flags)
10273 if (flags & PERF_EF_START)
10274 task_clock_event_start(event, flags);
10275 perf_event_update_userpage(event);
10280 static void task_clock_event_del(struct perf_event *event, int flags)
10282 task_clock_event_stop(event, PERF_EF_UPDATE);
10285 static void task_clock_event_read(struct perf_event *event)
10287 u64 now = perf_clock();
10288 u64 delta = now - event->ctx->timestamp;
10289 u64 time = event->ctx->time + delta;
10291 task_clock_event_update(event, time);
10294 static int task_clock_event_init(struct perf_event *event)
10296 if (event->attr.type != PERF_TYPE_SOFTWARE)
10299 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
10303 * no branch sampling for software events
10305 if (has_branch_stack(event))
10306 return -EOPNOTSUPP;
10308 perf_swevent_init_hrtimer(event);
10313 static struct pmu perf_task_clock = {
10314 .task_ctx_nr = perf_sw_context,
10316 .capabilities = PERF_PMU_CAP_NO_NMI,
10318 .event_init = task_clock_event_init,
10319 .add = task_clock_event_add,
10320 .del = task_clock_event_del,
10321 .start = task_clock_event_start,
10322 .stop = task_clock_event_stop,
10323 .read = task_clock_event_read,
10326 static void perf_pmu_nop_void(struct pmu *pmu)
10330 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
10334 static int perf_pmu_nop_int(struct pmu *pmu)
10339 static int perf_event_nop_int(struct perf_event *event, u64 value)
10344 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
10346 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
10348 __this_cpu_write(nop_txn_flags, flags);
10350 if (flags & ~PERF_PMU_TXN_ADD)
10353 perf_pmu_disable(pmu);
10356 static int perf_pmu_commit_txn(struct pmu *pmu)
10358 unsigned int flags = __this_cpu_read(nop_txn_flags);
10360 __this_cpu_write(nop_txn_flags, 0);
10362 if (flags & ~PERF_PMU_TXN_ADD)
10365 perf_pmu_enable(pmu);
10369 static void perf_pmu_cancel_txn(struct pmu *pmu)
10371 unsigned int flags = __this_cpu_read(nop_txn_flags);
10373 __this_cpu_write(nop_txn_flags, 0);
10375 if (flags & ~PERF_PMU_TXN_ADD)
10378 perf_pmu_enable(pmu);
10381 static int perf_event_idx_default(struct perf_event *event)
10387 * Ensures all contexts with the same task_ctx_nr have the same
10388 * pmu_cpu_context too.
10390 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
10397 list_for_each_entry(pmu, &pmus, entry) {
10398 if (pmu->task_ctx_nr == ctxn)
10399 return pmu->pmu_cpu_context;
10405 static void free_pmu_context(struct pmu *pmu)
10408 * Static contexts such as perf_sw_context have a global lifetime
10409 * and may be shared between different PMUs. Avoid freeing them
10410 * when a single PMU is going away.
10412 if (pmu->task_ctx_nr > perf_invalid_context)
10415 free_percpu(pmu->pmu_cpu_context);
10419 * Let userspace know that this PMU supports address range filtering:
10421 static ssize_t nr_addr_filters_show(struct device *dev,
10422 struct device_attribute *attr,
10425 struct pmu *pmu = dev_get_drvdata(dev);
10427 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
10429 DEVICE_ATTR_RO(nr_addr_filters);
10431 static struct idr pmu_idr;
10434 type_show(struct device *dev, struct device_attribute *attr, char *page)
10436 struct pmu *pmu = dev_get_drvdata(dev);
10438 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
10440 static DEVICE_ATTR_RO(type);
10443 perf_event_mux_interval_ms_show(struct device *dev,
10444 struct device_attribute *attr,
10447 struct pmu *pmu = dev_get_drvdata(dev);
10449 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
10452 static DEFINE_MUTEX(mux_interval_mutex);
10455 perf_event_mux_interval_ms_store(struct device *dev,
10456 struct device_attribute *attr,
10457 const char *buf, size_t count)
10459 struct pmu *pmu = dev_get_drvdata(dev);
10460 int timer, cpu, ret;
10462 ret = kstrtoint(buf, 0, &timer);
10469 /* same value, noting to do */
10470 if (timer == pmu->hrtimer_interval_ms)
10473 mutex_lock(&mux_interval_mutex);
10474 pmu->hrtimer_interval_ms = timer;
10476 /* update all cpuctx for this PMU */
10478 for_each_online_cpu(cpu) {
10479 struct perf_cpu_context *cpuctx;
10480 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10481 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
10483 cpu_function_call(cpu,
10484 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
10486 cpus_read_unlock();
10487 mutex_unlock(&mux_interval_mutex);
10491 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
10493 static struct attribute *pmu_dev_attrs[] = {
10494 &dev_attr_type.attr,
10495 &dev_attr_perf_event_mux_interval_ms.attr,
10498 ATTRIBUTE_GROUPS(pmu_dev);
10500 static int pmu_bus_running;
10501 static struct bus_type pmu_bus = {
10502 .name = "event_source",
10503 .dev_groups = pmu_dev_groups,
10506 static void pmu_dev_release(struct device *dev)
10511 static int pmu_dev_alloc(struct pmu *pmu)
10515 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
10519 pmu->dev->groups = pmu->attr_groups;
10520 device_initialize(pmu->dev);
10521 ret = dev_set_name(pmu->dev, "%s", pmu->name);
10525 dev_set_drvdata(pmu->dev, pmu);
10526 pmu->dev->bus = &pmu_bus;
10527 pmu->dev->release = pmu_dev_release;
10528 ret = device_add(pmu->dev);
10532 /* For PMUs with address filters, throw in an extra attribute: */
10533 if (pmu->nr_addr_filters)
10534 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
10539 if (pmu->attr_update)
10540 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
10549 device_del(pmu->dev);
10552 put_device(pmu->dev);
10556 static struct lock_class_key cpuctx_mutex;
10557 static struct lock_class_key cpuctx_lock;
10559 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
10561 int cpu, ret, max = PERF_TYPE_MAX;
10563 mutex_lock(&pmus_lock);
10565 pmu->pmu_disable_count = alloc_percpu(int);
10566 if (!pmu->pmu_disable_count)
10574 if (type != PERF_TYPE_SOFTWARE) {
10578 ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
10582 WARN_ON(type >= 0 && ret != type);
10588 if (pmu_bus_running) {
10589 ret = pmu_dev_alloc(pmu);
10595 if (pmu->task_ctx_nr == perf_hw_context) {
10596 static int hw_context_taken = 0;
10599 * Other than systems with heterogeneous CPUs, it never makes
10600 * sense for two PMUs to share perf_hw_context. PMUs which are
10601 * uncore must use perf_invalid_context.
10603 if (WARN_ON_ONCE(hw_context_taken &&
10604 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
10605 pmu->task_ctx_nr = perf_invalid_context;
10607 hw_context_taken = 1;
10610 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
10611 if (pmu->pmu_cpu_context)
10612 goto got_cpu_context;
10615 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
10616 if (!pmu->pmu_cpu_context)
10619 for_each_possible_cpu(cpu) {
10620 struct perf_cpu_context *cpuctx;
10622 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10623 __perf_event_init_context(&cpuctx->ctx);
10624 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
10625 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
10626 cpuctx->ctx.pmu = pmu;
10627 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
10629 __perf_mux_hrtimer_init(cpuctx, cpu);
10631 cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default);
10632 cpuctx->heap = cpuctx->heap_default;
10636 if (!pmu->start_txn) {
10637 if (pmu->pmu_enable) {
10639 * If we have pmu_enable/pmu_disable calls, install
10640 * transaction stubs that use that to try and batch
10641 * hardware accesses.
10643 pmu->start_txn = perf_pmu_start_txn;
10644 pmu->commit_txn = perf_pmu_commit_txn;
10645 pmu->cancel_txn = perf_pmu_cancel_txn;
10647 pmu->start_txn = perf_pmu_nop_txn;
10648 pmu->commit_txn = perf_pmu_nop_int;
10649 pmu->cancel_txn = perf_pmu_nop_void;
10653 if (!pmu->pmu_enable) {
10654 pmu->pmu_enable = perf_pmu_nop_void;
10655 pmu->pmu_disable = perf_pmu_nop_void;
10658 if (!pmu->check_period)
10659 pmu->check_period = perf_event_nop_int;
10661 if (!pmu->event_idx)
10662 pmu->event_idx = perf_event_idx_default;
10665 * Ensure the TYPE_SOFTWARE PMUs are at the head of the list,
10666 * since these cannot be in the IDR. This way the linear search
10667 * is fast, provided a valid software event is provided.
10669 if (type == PERF_TYPE_SOFTWARE || !name)
10670 list_add_rcu(&pmu->entry, &pmus);
10672 list_add_tail_rcu(&pmu->entry, &pmus);
10674 atomic_set(&pmu->exclusive_cnt, 0);
10677 mutex_unlock(&pmus_lock);
10682 device_del(pmu->dev);
10683 put_device(pmu->dev);
10686 if (pmu->type != PERF_TYPE_SOFTWARE)
10687 idr_remove(&pmu_idr, pmu->type);
10690 free_percpu(pmu->pmu_disable_count);
10693 EXPORT_SYMBOL_GPL(perf_pmu_register);
10695 void perf_pmu_unregister(struct pmu *pmu)
10697 mutex_lock(&pmus_lock);
10698 list_del_rcu(&pmu->entry);
10701 * We dereference the pmu list under both SRCU and regular RCU, so
10702 * synchronize against both of those.
10704 synchronize_srcu(&pmus_srcu);
10707 free_percpu(pmu->pmu_disable_count);
10708 if (pmu->type != PERF_TYPE_SOFTWARE)
10709 idr_remove(&pmu_idr, pmu->type);
10710 if (pmu_bus_running) {
10711 if (pmu->nr_addr_filters)
10712 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
10713 device_del(pmu->dev);
10714 put_device(pmu->dev);
10716 free_pmu_context(pmu);
10717 mutex_unlock(&pmus_lock);
10719 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
10721 static inline bool has_extended_regs(struct perf_event *event)
10723 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
10724 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
10727 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
10729 struct perf_event_context *ctx = NULL;
10732 if (!try_module_get(pmu->module))
10736 * A number of pmu->event_init() methods iterate the sibling_list to,
10737 * for example, validate if the group fits on the PMU. Therefore,
10738 * if this is a sibling event, acquire the ctx->mutex to protect
10739 * the sibling_list.
10741 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
10743 * This ctx->mutex can nest when we're called through
10744 * inheritance. See the perf_event_ctx_lock_nested() comment.
10746 ctx = perf_event_ctx_lock_nested(event->group_leader,
10747 SINGLE_DEPTH_NESTING);
10752 ret = pmu->event_init(event);
10755 perf_event_ctx_unlock(event->group_leader, ctx);
10758 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
10759 has_extended_regs(event))
10762 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
10763 event_has_any_exclude_flag(event))
10766 if (ret && event->destroy)
10767 event->destroy(event);
10771 module_put(pmu->module);
10776 static struct pmu *perf_init_event(struct perf_event *event)
10778 int idx, type, ret;
10781 idx = srcu_read_lock(&pmus_srcu);
10783 /* Try parent's PMU first: */
10784 if (event->parent && event->parent->pmu) {
10785 pmu = event->parent->pmu;
10786 ret = perf_try_init_event(pmu, event);
10792 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
10793 * are often aliases for PERF_TYPE_RAW.
10795 type = event->attr.type;
10796 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE)
10797 type = PERF_TYPE_RAW;
10801 pmu = idr_find(&pmu_idr, type);
10804 ret = perf_try_init_event(pmu, event);
10805 if (ret == -ENOENT && event->attr.type != type) {
10806 type = event->attr.type;
10811 pmu = ERR_PTR(ret);
10816 list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
10817 ret = perf_try_init_event(pmu, event);
10821 if (ret != -ENOENT) {
10822 pmu = ERR_PTR(ret);
10826 pmu = ERR_PTR(-ENOENT);
10828 srcu_read_unlock(&pmus_srcu, idx);
10833 static void attach_sb_event(struct perf_event *event)
10835 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
10837 raw_spin_lock(&pel->lock);
10838 list_add_rcu(&event->sb_list, &pel->list);
10839 raw_spin_unlock(&pel->lock);
10843 * We keep a list of all !task (and therefore per-cpu) events
10844 * that need to receive side-band records.
10846 * This avoids having to scan all the various PMU per-cpu contexts
10847 * looking for them.
10849 static void account_pmu_sb_event(struct perf_event *event)
10851 if (is_sb_event(event))
10852 attach_sb_event(event);
10855 static void account_event_cpu(struct perf_event *event, int cpu)
10860 if (is_cgroup_event(event))
10861 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
10864 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
10865 static void account_freq_event_nohz(void)
10867 #ifdef CONFIG_NO_HZ_FULL
10868 /* Lock so we don't race with concurrent unaccount */
10869 spin_lock(&nr_freq_lock);
10870 if (atomic_inc_return(&nr_freq_events) == 1)
10871 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
10872 spin_unlock(&nr_freq_lock);
10876 static void account_freq_event(void)
10878 if (tick_nohz_full_enabled())
10879 account_freq_event_nohz();
10881 atomic_inc(&nr_freq_events);
10885 static void account_event(struct perf_event *event)
10892 if (event->attach_state & PERF_ATTACH_TASK)
10894 if (event->attr.mmap || event->attr.mmap_data)
10895 atomic_inc(&nr_mmap_events);
10896 if (event->attr.comm)
10897 atomic_inc(&nr_comm_events);
10898 if (event->attr.namespaces)
10899 atomic_inc(&nr_namespaces_events);
10900 if (event->attr.cgroup)
10901 atomic_inc(&nr_cgroup_events);
10902 if (event->attr.task)
10903 atomic_inc(&nr_task_events);
10904 if (event->attr.freq)
10905 account_freq_event();
10906 if (event->attr.context_switch) {
10907 atomic_inc(&nr_switch_events);
10910 if (has_branch_stack(event))
10912 if (is_cgroup_event(event))
10914 if (event->attr.ksymbol)
10915 atomic_inc(&nr_ksymbol_events);
10916 if (event->attr.bpf_event)
10917 atomic_inc(&nr_bpf_events);
10921 * We need the mutex here because static_branch_enable()
10922 * must complete *before* the perf_sched_count increment
10925 if (atomic_inc_not_zero(&perf_sched_count))
10928 mutex_lock(&perf_sched_mutex);
10929 if (!atomic_read(&perf_sched_count)) {
10930 static_branch_enable(&perf_sched_events);
10932 * Guarantee that all CPUs observe they key change and
10933 * call the perf scheduling hooks before proceeding to
10934 * install events that need them.
10939 * Now that we have waited for the sync_sched(), allow further
10940 * increments to by-pass the mutex.
10942 atomic_inc(&perf_sched_count);
10943 mutex_unlock(&perf_sched_mutex);
10947 account_event_cpu(event, event->cpu);
10949 account_pmu_sb_event(event);
10953 * Allocate and initialize an event structure
10955 static struct perf_event *
10956 perf_event_alloc(struct perf_event_attr *attr, int cpu,
10957 struct task_struct *task,
10958 struct perf_event *group_leader,
10959 struct perf_event *parent_event,
10960 perf_overflow_handler_t overflow_handler,
10961 void *context, int cgroup_fd)
10964 struct perf_event *event;
10965 struct hw_perf_event *hwc;
10966 long err = -EINVAL;
10968 if ((unsigned)cpu >= nr_cpu_ids) {
10969 if (!task || cpu != -1)
10970 return ERR_PTR(-EINVAL);
10973 event = kzalloc(sizeof(*event), GFP_KERNEL);
10975 return ERR_PTR(-ENOMEM);
10978 * Single events are their own group leaders, with an
10979 * empty sibling list:
10982 group_leader = event;
10984 mutex_init(&event->child_mutex);
10985 INIT_LIST_HEAD(&event->child_list);
10987 INIT_LIST_HEAD(&event->event_entry);
10988 INIT_LIST_HEAD(&event->sibling_list);
10989 INIT_LIST_HEAD(&event->active_list);
10990 init_event_group(event);
10991 INIT_LIST_HEAD(&event->rb_entry);
10992 INIT_LIST_HEAD(&event->active_entry);
10993 INIT_LIST_HEAD(&event->addr_filters.list);
10994 INIT_HLIST_NODE(&event->hlist_entry);
10997 init_waitqueue_head(&event->waitq);
10998 event->pending_disable = -1;
10999 init_irq_work(&event->pending, perf_pending_event);
11001 mutex_init(&event->mmap_mutex);
11002 raw_spin_lock_init(&event->addr_filters.lock);
11004 atomic_long_set(&event->refcount, 1);
11006 event->attr = *attr;
11007 event->group_leader = group_leader;
11011 event->parent = parent_event;
11013 event->ns = get_pid_ns(task_active_pid_ns(current));
11014 event->id = atomic64_inc_return(&perf_event_id);
11016 event->state = PERF_EVENT_STATE_INACTIVE;
11019 event->attach_state = PERF_ATTACH_TASK;
11021 * XXX pmu::event_init needs to know what task to account to
11022 * and we cannot use the ctx information because we need the
11023 * pmu before we get a ctx.
11025 event->hw.target = get_task_struct(task);
11028 event->clock = &local_clock;
11030 event->clock = parent_event->clock;
11032 if (!overflow_handler && parent_event) {
11033 overflow_handler = parent_event->overflow_handler;
11034 context = parent_event->overflow_handler_context;
11035 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
11036 if (overflow_handler == bpf_overflow_handler) {
11037 struct bpf_prog *prog = parent_event->prog;
11039 bpf_prog_inc(prog);
11040 event->prog = prog;
11041 event->orig_overflow_handler =
11042 parent_event->orig_overflow_handler;
11047 if (overflow_handler) {
11048 event->overflow_handler = overflow_handler;
11049 event->overflow_handler_context = context;
11050 } else if (is_write_backward(event)){
11051 event->overflow_handler = perf_event_output_backward;
11052 event->overflow_handler_context = NULL;
11054 event->overflow_handler = perf_event_output_forward;
11055 event->overflow_handler_context = NULL;
11058 perf_event__state_init(event);
11063 hwc->sample_period = attr->sample_period;
11064 if (attr->freq && attr->sample_freq)
11065 hwc->sample_period = 1;
11066 hwc->last_period = hwc->sample_period;
11068 local64_set(&hwc->period_left, hwc->sample_period);
11071 * We currently do not support PERF_SAMPLE_READ on inherited events.
11072 * See perf_output_read().
11074 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
11077 if (!has_branch_stack(event))
11078 event->attr.branch_sample_type = 0;
11080 pmu = perf_init_event(event);
11082 err = PTR_ERR(pmu);
11087 * Disallow uncore-cgroup events, they don't make sense as the cgroup will
11088 * be different on other CPUs in the uncore mask.
11090 if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) {
11095 if (event->attr.aux_output &&
11096 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
11101 if (cgroup_fd != -1) {
11102 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
11107 err = exclusive_event_init(event);
11111 if (has_addr_filter(event)) {
11112 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
11113 sizeof(struct perf_addr_filter_range),
11115 if (!event->addr_filter_ranges) {
11121 * Clone the parent's vma offsets: they are valid until exec()
11122 * even if the mm is not shared with the parent.
11124 if (event->parent) {
11125 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
11127 raw_spin_lock_irq(&ifh->lock);
11128 memcpy(event->addr_filter_ranges,
11129 event->parent->addr_filter_ranges,
11130 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
11131 raw_spin_unlock_irq(&ifh->lock);
11134 /* force hw sync on the address filters */
11135 event->addr_filters_gen = 1;
11138 if (!event->parent) {
11139 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
11140 err = get_callchain_buffers(attr->sample_max_stack);
11142 goto err_addr_filters;
11146 err = security_perf_event_alloc(event);
11148 goto err_callchain_buffer;
11150 /* symmetric to unaccount_event() in _free_event() */
11151 account_event(event);
11155 err_callchain_buffer:
11156 if (!event->parent) {
11157 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
11158 put_callchain_buffers();
11161 kfree(event->addr_filter_ranges);
11164 exclusive_event_destroy(event);
11167 if (is_cgroup_event(event))
11168 perf_detach_cgroup(event);
11169 if (event->destroy)
11170 event->destroy(event);
11171 module_put(pmu->module);
11174 put_pid_ns(event->ns);
11175 if (event->hw.target)
11176 put_task_struct(event->hw.target);
11179 return ERR_PTR(err);
11182 static int perf_copy_attr(struct perf_event_attr __user *uattr,
11183 struct perf_event_attr *attr)
11188 /* Zero the full structure, so that a short copy will be nice. */
11189 memset(attr, 0, sizeof(*attr));
11191 ret = get_user(size, &uattr->size);
11195 /* ABI compatibility quirk: */
11197 size = PERF_ATTR_SIZE_VER0;
11198 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
11201 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
11210 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
11213 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
11216 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
11219 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
11220 u64 mask = attr->branch_sample_type;
11222 /* only using defined bits */
11223 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
11226 /* at least one branch bit must be set */
11227 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
11230 /* propagate priv level, when not set for branch */
11231 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
11233 /* exclude_kernel checked on syscall entry */
11234 if (!attr->exclude_kernel)
11235 mask |= PERF_SAMPLE_BRANCH_KERNEL;
11237 if (!attr->exclude_user)
11238 mask |= PERF_SAMPLE_BRANCH_USER;
11240 if (!attr->exclude_hv)
11241 mask |= PERF_SAMPLE_BRANCH_HV;
11243 * adjust user setting (for HW filter setup)
11245 attr->branch_sample_type = mask;
11247 /* privileged levels capture (kernel, hv): check permissions */
11248 if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
11249 ret = perf_allow_kernel(attr);
11255 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
11256 ret = perf_reg_validate(attr->sample_regs_user);
11261 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
11262 if (!arch_perf_have_user_stack_dump())
11266 * We have __u32 type for the size, but so far
11267 * we can only use __u16 as maximum due to the
11268 * __u16 sample size limit.
11270 if (attr->sample_stack_user >= USHRT_MAX)
11272 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
11276 if (!attr->sample_max_stack)
11277 attr->sample_max_stack = sysctl_perf_event_max_stack;
11279 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
11280 ret = perf_reg_validate(attr->sample_regs_intr);
11282 #ifndef CONFIG_CGROUP_PERF
11283 if (attr->sample_type & PERF_SAMPLE_CGROUP)
11291 put_user(sizeof(*attr), &uattr->size);
11297 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
11299 struct perf_buffer *rb = NULL;
11305 /* don't allow circular references */
11306 if (event == output_event)
11310 * Don't allow cross-cpu buffers
11312 if (output_event->cpu != event->cpu)
11316 * If its not a per-cpu rb, it must be the same task.
11318 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
11322 * Mixing clocks in the same buffer is trouble you don't need.
11324 if (output_event->clock != event->clock)
11328 * Either writing ring buffer from beginning or from end.
11329 * Mixing is not allowed.
11331 if (is_write_backward(output_event) != is_write_backward(event))
11335 * If both events generate aux data, they must be on the same PMU
11337 if (has_aux(event) && has_aux(output_event) &&
11338 event->pmu != output_event->pmu)
11342 mutex_lock(&event->mmap_mutex);
11343 /* Can't redirect output if we've got an active mmap() */
11344 if (atomic_read(&event->mmap_count))
11347 if (output_event) {
11348 /* get the rb we want to redirect to */
11349 rb = ring_buffer_get(output_event);
11354 ring_buffer_attach(event, rb);
11358 mutex_unlock(&event->mmap_mutex);
11364 static void mutex_lock_double(struct mutex *a, struct mutex *b)
11370 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
11373 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
11375 bool nmi_safe = false;
11378 case CLOCK_MONOTONIC:
11379 event->clock = &ktime_get_mono_fast_ns;
11383 case CLOCK_MONOTONIC_RAW:
11384 event->clock = &ktime_get_raw_fast_ns;
11388 case CLOCK_REALTIME:
11389 event->clock = &ktime_get_real_ns;
11392 case CLOCK_BOOTTIME:
11393 event->clock = &ktime_get_boottime_ns;
11397 event->clock = &ktime_get_clocktai_ns;
11404 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
11411 * Variation on perf_event_ctx_lock_nested(), except we take two context
11414 static struct perf_event_context *
11415 __perf_event_ctx_lock_double(struct perf_event *group_leader,
11416 struct perf_event_context *ctx)
11418 struct perf_event_context *gctx;
11422 gctx = READ_ONCE(group_leader->ctx);
11423 if (!refcount_inc_not_zero(&gctx->refcount)) {
11429 mutex_lock_double(&gctx->mutex, &ctx->mutex);
11431 if (group_leader->ctx != gctx) {
11432 mutex_unlock(&ctx->mutex);
11433 mutex_unlock(&gctx->mutex);
11442 * sys_perf_event_open - open a performance event, associate it to a task/cpu
11444 * @attr_uptr: event_id type attributes for monitoring/sampling
11447 * @group_fd: group leader event fd
11449 SYSCALL_DEFINE5(perf_event_open,
11450 struct perf_event_attr __user *, attr_uptr,
11451 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
11453 struct perf_event *group_leader = NULL, *output_event = NULL;
11454 struct perf_event *event, *sibling;
11455 struct perf_event_attr attr;
11456 struct perf_event_context *ctx, *uninitialized_var(gctx);
11457 struct file *event_file = NULL;
11458 struct fd group = {NULL, 0};
11459 struct task_struct *task = NULL;
11462 int move_group = 0;
11464 int f_flags = O_RDWR;
11465 int cgroup_fd = -1;
11467 /* for future expandability... */
11468 if (flags & ~PERF_FLAG_ALL)
11471 /* Do we allow access to perf_event_open(2) ? */
11472 err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
11476 err = perf_copy_attr(attr_uptr, &attr);
11480 if (!attr.exclude_kernel) {
11481 err = perf_allow_kernel(&attr);
11486 if (attr.namespaces) {
11487 if (!capable(CAP_SYS_ADMIN))
11492 if (attr.sample_freq > sysctl_perf_event_sample_rate)
11495 if (attr.sample_period & (1ULL << 63))
11499 /* Only privileged users can get physical addresses */
11500 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
11501 err = perf_allow_kernel(&attr);
11506 err = security_locked_down(LOCKDOWN_PERF);
11507 if (err && (attr.sample_type & PERF_SAMPLE_REGS_INTR))
11508 /* REGS_INTR can leak data, lockdown must prevent this */
11514 * In cgroup mode, the pid argument is used to pass the fd
11515 * opened to the cgroup directory in cgroupfs. The cpu argument
11516 * designates the cpu on which to monitor threads from that
11519 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
11522 if (flags & PERF_FLAG_FD_CLOEXEC)
11523 f_flags |= O_CLOEXEC;
11525 event_fd = get_unused_fd_flags(f_flags);
11529 if (group_fd != -1) {
11530 err = perf_fget_light(group_fd, &group);
11533 group_leader = group.file->private_data;
11534 if (flags & PERF_FLAG_FD_OUTPUT)
11535 output_event = group_leader;
11536 if (flags & PERF_FLAG_FD_NO_GROUP)
11537 group_leader = NULL;
11540 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
11541 task = find_lively_task_by_vpid(pid);
11542 if (IS_ERR(task)) {
11543 err = PTR_ERR(task);
11548 if (task && group_leader &&
11549 group_leader->attr.inherit != attr.inherit) {
11555 err = mutex_lock_interruptible(&task->signal->exec_update_mutex);
11560 * Reuse ptrace permission checks for now.
11562 * We must hold exec_update_mutex across this and any potential
11563 * perf_install_in_context() call for this new event to
11564 * serialize against exec() altering our credentials (and the
11565 * perf_event_exit_task() that could imply).
11568 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
11572 if (flags & PERF_FLAG_PID_CGROUP)
11575 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
11576 NULL, NULL, cgroup_fd);
11577 if (IS_ERR(event)) {
11578 err = PTR_ERR(event);
11582 if (is_sampling_event(event)) {
11583 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
11590 * Special case software events and allow them to be part of
11591 * any hardware group.
11595 if (attr.use_clockid) {
11596 err = perf_event_set_clock(event, attr.clockid);
11601 if (pmu->task_ctx_nr == perf_sw_context)
11602 event->event_caps |= PERF_EV_CAP_SOFTWARE;
11604 if (group_leader) {
11605 if (is_software_event(event) &&
11606 !in_software_context(group_leader)) {
11608 * If the event is a sw event, but the group_leader
11609 * is on hw context.
11611 * Allow the addition of software events to hw
11612 * groups, this is safe because software events
11613 * never fail to schedule.
11615 pmu = group_leader->ctx->pmu;
11616 } else if (!is_software_event(event) &&
11617 is_software_event(group_leader) &&
11618 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11620 * In case the group is a pure software group, and we
11621 * try to add a hardware event, move the whole group to
11622 * the hardware context.
11629 * Get the target context (task or percpu):
11631 ctx = find_get_context(pmu, task, event);
11633 err = PTR_ERR(ctx);
11638 * Look up the group leader (we will attach this event to it):
11640 if (group_leader) {
11644 * Do not allow a recursive hierarchy (this new sibling
11645 * becoming part of another group-sibling):
11647 if (group_leader->group_leader != group_leader)
11650 /* All events in a group should have the same clock */
11651 if (group_leader->clock != event->clock)
11655 * Make sure we're both events for the same CPU;
11656 * grouping events for different CPUs is broken; since
11657 * you can never concurrently schedule them anyhow.
11659 if (group_leader->cpu != event->cpu)
11663 * Make sure we're both on the same task, or both
11666 if (group_leader->ctx->task != ctx->task)
11670 * Do not allow to attach to a group in a different task
11671 * or CPU context. If we're moving SW events, we'll fix
11672 * this up later, so allow that.
11674 if (!move_group && group_leader->ctx != ctx)
11678 * Only a group leader can be exclusive or pinned
11680 if (attr.exclusive || attr.pinned)
11684 if (output_event) {
11685 err = perf_event_set_output(event, output_event);
11690 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
11692 if (IS_ERR(event_file)) {
11693 err = PTR_ERR(event_file);
11699 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
11701 if (gctx->task == TASK_TOMBSTONE) {
11707 * Check if we raced against another sys_perf_event_open() call
11708 * moving the software group underneath us.
11710 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11712 * If someone moved the group out from under us, check
11713 * if this new event wound up on the same ctx, if so
11714 * its the regular !move_group case, otherwise fail.
11720 perf_event_ctx_unlock(group_leader, gctx);
11726 * Failure to create exclusive events returns -EBUSY.
11729 if (!exclusive_event_installable(group_leader, ctx))
11732 for_each_sibling_event(sibling, group_leader) {
11733 if (!exclusive_event_installable(sibling, ctx))
11737 mutex_lock(&ctx->mutex);
11740 if (ctx->task == TASK_TOMBSTONE) {
11745 if (!perf_event_validate_size(event)) {
11752 * Check if the @cpu we're creating an event for is online.
11754 * We use the perf_cpu_context::ctx::mutex to serialize against
11755 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11757 struct perf_cpu_context *cpuctx =
11758 container_of(ctx, struct perf_cpu_context, ctx);
11760 if (!cpuctx->online) {
11766 if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
11772 * Must be under the same ctx::mutex as perf_install_in_context(),
11773 * because we need to serialize with concurrent event creation.
11775 if (!exclusive_event_installable(event, ctx)) {
11780 WARN_ON_ONCE(ctx->parent_ctx);
11783 * This is the point on no return; we cannot fail hereafter. This is
11784 * where we start modifying current state.
11789 * See perf_event_ctx_lock() for comments on the details
11790 * of swizzling perf_event::ctx.
11792 perf_remove_from_context(group_leader, 0);
11795 for_each_sibling_event(sibling, group_leader) {
11796 perf_remove_from_context(sibling, 0);
11801 * Wait for everybody to stop referencing the events through
11802 * the old lists, before installing it on new lists.
11807 * Install the group siblings before the group leader.
11809 * Because a group leader will try and install the entire group
11810 * (through the sibling list, which is still in-tact), we can
11811 * end up with siblings installed in the wrong context.
11813 * By installing siblings first we NO-OP because they're not
11814 * reachable through the group lists.
11816 for_each_sibling_event(sibling, group_leader) {
11817 perf_event__state_init(sibling);
11818 perf_install_in_context(ctx, sibling, sibling->cpu);
11823 * Removing from the context ends up with disabled
11824 * event. What we want here is event in the initial
11825 * startup state, ready to be add into new context.
11827 perf_event__state_init(group_leader);
11828 perf_install_in_context(ctx, group_leader, group_leader->cpu);
11833 * Precalculate sample_data sizes; do while holding ctx::mutex such
11834 * that we're serialized against further additions and before
11835 * perf_install_in_context() which is the point the event is active and
11836 * can use these values.
11838 perf_event__header_size(event);
11839 perf_event__id_header_size(event);
11841 event->owner = current;
11843 perf_install_in_context(ctx, event, event->cpu);
11844 perf_unpin_context(ctx);
11847 perf_event_ctx_unlock(group_leader, gctx);
11848 mutex_unlock(&ctx->mutex);
11851 mutex_unlock(&task->signal->exec_update_mutex);
11852 put_task_struct(task);
11855 mutex_lock(¤t->perf_event_mutex);
11856 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
11857 mutex_unlock(¤t->perf_event_mutex);
11860 * Drop the reference on the group_event after placing the
11861 * new event on the sibling_list. This ensures destruction
11862 * of the group leader will find the pointer to itself in
11863 * perf_group_detach().
11866 fd_install(event_fd, event_file);
11871 perf_event_ctx_unlock(group_leader, gctx);
11872 mutex_unlock(&ctx->mutex);
11876 perf_unpin_context(ctx);
11880 * If event_file is set, the fput() above will have called ->release()
11881 * and that will take care of freeing the event.
11887 mutex_unlock(&task->signal->exec_update_mutex);
11890 put_task_struct(task);
11894 put_unused_fd(event_fd);
11899 * perf_event_create_kernel_counter
11901 * @attr: attributes of the counter to create
11902 * @cpu: cpu in which the counter is bound
11903 * @task: task to profile (NULL for percpu)
11905 struct perf_event *
11906 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
11907 struct task_struct *task,
11908 perf_overflow_handler_t overflow_handler,
11911 struct perf_event_context *ctx;
11912 struct perf_event *event;
11916 * Grouping is not supported for kernel events, neither is 'AUX',
11917 * make sure the caller's intentions are adjusted.
11919 if (attr->aux_output)
11920 return ERR_PTR(-EINVAL);
11922 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
11923 overflow_handler, context, -1);
11924 if (IS_ERR(event)) {
11925 err = PTR_ERR(event);
11929 /* Mark owner so we could distinguish it from user events. */
11930 event->owner = TASK_TOMBSTONE;
11933 * Get the target context (task or percpu):
11935 ctx = find_get_context(event->pmu, task, event);
11937 err = PTR_ERR(ctx);
11941 WARN_ON_ONCE(ctx->parent_ctx);
11942 mutex_lock(&ctx->mutex);
11943 if (ctx->task == TASK_TOMBSTONE) {
11950 * Check if the @cpu we're creating an event for is online.
11952 * We use the perf_cpu_context::ctx::mutex to serialize against
11953 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11955 struct perf_cpu_context *cpuctx =
11956 container_of(ctx, struct perf_cpu_context, ctx);
11957 if (!cpuctx->online) {
11963 if (!exclusive_event_installable(event, ctx)) {
11968 perf_install_in_context(ctx, event, event->cpu);
11969 perf_unpin_context(ctx);
11970 mutex_unlock(&ctx->mutex);
11975 mutex_unlock(&ctx->mutex);
11976 perf_unpin_context(ctx);
11981 return ERR_PTR(err);
11983 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
11985 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
11987 struct perf_event_context *src_ctx;
11988 struct perf_event_context *dst_ctx;
11989 struct perf_event *event, *tmp;
11992 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
11993 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
11996 * See perf_event_ctx_lock() for comments on the details
11997 * of swizzling perf_event::ctx.
11999 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
12000 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
12002 perf_remove_from_context(event, 0);
12003 unaccount_event_cpu(event, src_cpu);
12005 list_add(&event->migrate_entry, &events);
12009 * Wait for the events to quiesce before re-instating them.
12014 * Re-instate events in 2 passes.
12016 * Skip over group leaders and only install siblings on this first
12017 * pass, siblings will not get enabled without a leader, however a
12018 * leader will enable its siblings, even if those are still on the old
12021 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12022 if (event->group_leader == event)
12025 list_del(&event->migrate_entry);
12026 if (event->state >= PERF_EVENT_STATE_OFF)
12027 event->state = PERF_EVENT_STATE_INACTIVE;
12028 account_event_cpu(event, dst_cpu);
12029 perf_install_in_context(dst_ctx, event, dst_cpu);
12034 * Once all the siblings are setup properly, install the group leaders
12037 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12038 list_del(&event->migrate_entry);
12039 if (event->state >= PERF_EVENT_STATE_OFF)
12040 event->state = PERF_EVENT_STATE_INACTIVE;
12041 account_event_cpu(event, dst_cpu);
12042 perf_install_in_context(dst_ctx, event, dst_cpu);
12045 mutex_unlock(&dst_ctx->mutex);
12046 mutex_unlock(&src_ctx->mutex);
12048 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
12050 static void sync_child_event(struct perf_event *child_event,
12051 struct task_struct *child)
12053 struct perf_event *parent_event = child_event->parent;
12056 if (child_event->attr.inherit_stat)
12057 perf_event_read_event(child_event, child);
12059 child_val = perf_event_count(child_event);
12062 * Add back the child's count to the parent's count:
12064 atomic64_add(child_val, &parent_event->child_count);
12065 atomic64_add(child_event->total_time_enabled,
12066 &parent_event->child_total_time_enabled);
12067 atomic64_add(child_event->total_time_running,
12068 &parent_event->child_total_time_running);
12072 perf_event_exit_event(struct perf_event *child_event,
12073 struct perf_event_context *child_ctx,
12074 struct task_struct *child)
12076 struct perf_event *parent_event = child_event->parent;
12079 * Do not destroy the 'original' grouping; because of the context
12080 * switch optimization the original events could've ended up in a
12081 * random child task.
12083 * If we were to destroy the original group, all group related
12084 * operations would cease to function properly after this random
12087 * Do destroy all inherited groups, we don't care about those
12088 * and being thorough is better.
12090 raw_spin_lock_irq(&child_ctx->lock);
12091 WARN_ON_ONCE(child_ctx->is_active);
12094 perf_group_detach(child_event);
12095 list_del_event(child_event, child_ctx);
12096 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
12097 raw_spin_unlock_irq(&child_ctx->lock);
12100 * Parent events are governed by their filedesc, retain them.
12102 if (!parent_event) {
12103 perf_event_wakeup(child_event);
12107 * Child events can be cleaned up.
12110 sync_child_event(child_event, child);
12113 * Remove this event from the parent's list
12115 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
12116 mutex_lock(&parent_event->child_mutex);
12117 list_del_init(&child_event->child_list);
12118 mutex_unlock(&parent_event->child_mutex);
12121 * Kick perf_poll() for is_event_hup().
12123 perf_event_wakeup(parent_event);
12124 free_event(child_event);
12125 put_event(parent_event);
12128 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
12130 struct perf_event_context *child_ctx, *clone_ctx = NULL;
12131 struct perf_event *child_event, *next;
12133 WARN_ON_ONCE(child != current);
12135 child_ctx = perf_pin_task_context(child, ctxn);
12140 * In order to reduce the amount of tricky in ctx tear-down, we hold
12141 * ctx::mutex over the entire thing. This serializes against almost
12142 * everything that wants to access the ctx.
12144 * The exception is sys_perf_event_open() /
12145 * perf_event_create_kernel_count() which does find_get_context()
12146 * without ctx::mutex (it cannot because of the move_group double mutex
12147 * lock thing). See the comments in perf_install_in_context().
12149 mutex_lock(&child_ctx->mutex);
12152 * In a single ctx::lock section, de-schedule the events and detach the
12153 * context from the task such that we cannot ever get it scheduled back
12156 raw_spin_lock_irq(&child_ctx->lock);
12157 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
12160 * Now that the context is inactive, destroy the task <-> ctx relation
12161 * and mark the context dead.
12163 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
12164 put_ctx(child_ctx); /* cannot be last */
12165 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
12166 put_task_struct(current); /* cannot be last */
12168 clone_ctx = unclone_ctx(child_ctx);
12169 raw_spin_unlock_irq(&child_ctx->lock);
12172 put_ctx(clone_ctx);
12175 * Report the task dead after unscheduling the events so that we
12176 * won't get any samples after PERF_RECORD_EXIT. We can however still
12177 * get a few PERF_RECORD_READ events.
12179 perf_event_task(child, child_ctx, 0);
12181 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
12182 perf_event_exit_event(child_event, child_ctx, child);
12184 mutex_unlock(&child_ctx->mutex);
12186 put_ctx(child_ctx);
12190 * When a child task exits, feed back event values to parent events.
12192 * Can be called with exec_update_mutex held when called from
12193 * install_exec_creds().
12195 void perf_event_exit_task(struct task_struct *child)
12197 struct perf_event *event, *tmp;
12200 mutex_lock(&child->perf_event_mutex);
12201 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
12203 list_del_init(&event->owner_entry);
12206 * Ensure the list deletion is visible before we clear
12207 * the owner, closes a race against perf_release() where
12208 * we need to serialize on the owner->perf_event_mutex.
12210 smp_store_release(&event->owner, NULL);
12212 mutex_unlock(&child->perf_event_mutex);
12214 for_each_task_context_nr(ctxn)
12215 perf_event_exit_task_context(child, ctxn);
12218 * The perf_event_exit_task_context calls perf_event_task
12219 * with child's task_ctx, which generates EXIT events for
12220 * child contexts and sets child->perf_event_ctxp[] to NULL.
12221 * At this point we need to send EXIT events to cpu contexts.
12223 perf_event_task(child, NULL, 0);
12226 static void perf_free_event(struct perf_event *event,
12227 struct perf_event_context *ctx)
12229 struct perf_event *parent = event->parent;
12231 if (WARN_ON_ONCE(!parent))
12234 mutex_lock(&parent->child_mutex);
12235 list_del_init(&event->child_list);
12236 mutex_unlock(&parent->child_mutex);
12240 raw_spin_lock_irq(&ctx->lock);
12241 perf_group_detach(event);
12242 list_del_event(event, ctx);
12243 raw_spin_unlock_irq(&ctx->lock);
12248 * Free a context as created by inheritance by perf_event_init_task() below,
12249 * used by fork() in case of fail.
12251 * Even though the task has never lived, the context and events have been
12252 * exposed through the child_list, so we must take care tearing it all down.
12254 void perf_event_free_task(struct task_struct *task)
12256 struct perf_event_context *ctx;
12257 struct perf_event *event, *tmp;
12260 for_each_task_context_nr(ctxn) {
12261 ctx = task->perf_event_ctxp[ctxn];
12265 mutex_lock(&ctx->mutex);
12266 raw_spin_lock_irq(&ctx->lock);
12268 * Destroy the task <-> ctx relation and mark the context dead.
12270 * This is important because even though the task hasn't been
12271 * exposed yet the context has been (through child_list).
12273 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
12274 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
12275 put_task_struct(task); /* cannot be last */
12276 raw_spin_unlock_irq(&ctx->lock);
12278 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
12279 perf_free_event(event, ctx);
12281 mutex_unlock(&ctx->mutex);
12284 * perf_event_release_kernel() could've stolen some of our
12285 * child events and still have them on its free_list. In that
12286 * case we must wait for these events to have been freed (in
12287 * particular all their references to this task must've been
12290 * Without this copy_process() will unconditionally free this
12291 * task (irrespective of its reference count) and
12292 * _free_event()'s put_task_struct(event->hw.target) will be a
12295 * Wait for all events to drop their context reference.
12297 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
12298 put_ctx(ctx); /* must be last */
12302 void perf_event_delayed_put(struct task_struct *task)
12306 for_each_task_context_nr(ctxn)
12307 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
12310 struct file *perf_event_get(unsigned int fd)
12312 struct file *file = fget(fd);
12314 return ERR_PTR(-EBADF);
12316 if (file->f_op != &perf_fops) {
12318 return ERR_PTR(-EBADF);
12324 const struct perf_event *perf_get_event(struct file *file)
12326 if (file->f_op != &perf_fops)
12327 return ERR_PTR(-EINVAL);
12329 return file->private_data;
12332 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
12335 return ERR_PTR(-EINVAL);
12337 return &event->attr;
12341 * Inherit an event from parent task to child task.
12344 * - valid pointer on success
12345 * - NULL for orphaned events
12346 * - IS_ERR() on error
12348 static struct perf_event *
12349 inherit_event(struct perf_event *parent_event,
12350 struct task_struct *parent,
12351 struct perf_event_context *parent_ctx,
12352 struct task_struct *child,
12353 struct perf_event *group_leader,
12354 struct perf_event_context *child_ctx)
12356 enum perf_event_state parent_state = parent_event->state;
12357 struct perf_event *child_event;
12358 unsigned long flags;
12361 * Instead of creating recursive hierarchies of events,
12362 * we link inherited events back to the original parent,
12363 * which has a filp for sure, which we use as the reference
12366 if (parent_event->parent)
12367 parent_event = parent_event->parent;
12369 child_event = perf_event_alloc(&parent_event->attr,
12372 group_leader, parent_event,
12374 if (IS_ERR(child_event))
12375 return child_event;
12378 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
12379 !child_ctx->task_ctx_data) {
12380 struct pmu *pmu = child_event->pmu;
12382 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
12384 if (!child_ctx->task_ctx_data) {
12385 free_event(child_event);
12386 return ERR_PTR(-ENOMEM);
12391 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
12392 * must be under the same lock in order to serialize against
12393 * perf_event_release_kernel(), such that either we must observe
12394 * is_orphaned_event() or they will observe us on the child_list.
12396 mutex_lock(&parent_event->child_mutex);
12397 if (is_orphaned_event(parent_event) ||
12398 !atomic_long_inc_not_zero(&parent_event->refcount)) {
12399 mutex_unlock(&parent_event->child_mutex);
12400 /* task_ctx_data is freed with child_ctx */
12401 free_event(child_event);
12405 get_ctx(child_ctx);
12408 * Make the child state follow the state of the parent event,
12409 * not its attr.disabled bit. We hold the parent's mutex,
12410 * so we won't race with perf_event_{en, dis}able_family.
12412 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
12413 child_event->state = PERF_EVENT_STATE_INACTIVE;
12415 child_event->state = PERF_EVENT_STATE_OFF;
12417 if (parent_event->attr.freq) {
12418 u64 sample_period = parent_event->hw.sample_period;
12419 struct hw_perf_event *hwc = &child_event->hw;
12421 hwc->sample_period = sample_period;
12422 hwc->last_period = sample_period;
12424 local64_set(&hwc->period_left, sample_period);
12427 child_event->ctx = child_ctx;
12428 child_event->overflow_handler = parent_event->overflow_handler;
12429 child_event->overflow_handler_context
12430 = parent_event->overflow_handler_context;
12433 * Precalculate sample_data sizes
12435 perf_event__header_size(child_event);
12436 perf_event__id_header_size(child_event);
12439 * Link it up in the child's context:
12441 raw_spin_lock_irqsave(&child_ctx->lock, flags);
12442 add_event_to_ctx(child_event, child_ctx);
12443 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
12446 * Link this into the parent event's child list
12448 list_add_tail(&child_event->child_list, &parent_event->child_list);
12449 mutex_unlock(&parent_event->child_mutex);
12451 return child_event;
12455 * Inherits an event group.
12457 * This will quietly suppress orphaned events; !inherit_event() is not an error.
12458 * This matches with perf_event_release_kernel() removing all child events.
12464 static int inherit_group(struct perf_event *parent_event,
12465 struct task_struct *parent,
12466 struct perf_event_context *parent_ctx,
12467 struct task_struct *child,
12468 struct perf_event_context *child_ctx)
12470 struct perf_event *leader;
12471 struct perf_event *sub;
12472 struct perf_event *child_ctr;
12474 leader = inherit_event(parent_event, parent, parent_ctx,
12475 child, NULL, child_ctx);
12476 if (IS_ERR(leader))
12477 return PTR_ERR(leader);
12479 * @leader can be NULL here because of is_orphaned_event(). In this
12480 * case inherit_event() will create individual events, similar to what
12481 * perf_group_detach() would do anyway.
12483 for_each_sibling_event(sub, parent_event) {
12484 child_ctr = inherit_event(sub, parent, parent_ctx,
12485 child, leader, child_ctx);
12486 if (IS_ERR(child_ctr))
12487 return PTR_ERR(child_ctr);
12489 if (sub->aux_event == parent_event && child_ctr &&
12490 !perf_get_aux_event(child_ctr, leader))
12497 * Creates the child task context and tries to inherit the event-group.
12499 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
12500 * inherited_all set when we 'fail' to inherit an orphaned event; this is
12501 * consistent with perf_event_release_kernel() removing all child events.
12508 inherit_task_group(struct perf_event *event, struct task_struct *parent,
12509 struct perf_event_context *parent_ctx,
12510 struct task_struct *child, int ctxn,
12511 int *inherited_all)
12514 struct perf_event_context *child_ctx;
12516 if (!event->attr.inherit) {
12517 *inherited_all = 0;
12521 child_ctx = child->perf_event_ctxp[ctxn];
12524 * This is executed from the parent task context, so
12525 * inherit events that have been marked for cloning.
12526 * First allocate and initialize a context for the
12529 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
12533 child->perf_event_ctxp[ctxn] = child_ctx;
12536 ret = inherit_group(event, parent, parent_ctx,
12540 *inherited_all = 0;
12546 * Initialize the perf_event context in task_struct
12548 static int perf_event_init_context(struct task_struct *child, int ctxn)
12550 struct perf_event_context *child_ctx, *parent_ctx;
12551 struct perf_event_context *cloned_ctx;
12552 struct perf_event *event;
12553 struct task_struct *parent = current;
12554 int inherited_all = 1;
12555 unsigned long flags;
12558 if (likely(!parent->perf_event_ctxp[ctxn]))
12562 * If the parent's context is a clone, pin it so it won't get
12563 * swapped under us.
12565 parent_ctx = perf_pin_task_context(parent, ctxn);
12570 * No need to check if parent_ctx != NULL here; since we saw
12571 * it non-NULL earlier, the only reason for it to become NULL
12572 * is if we exit, and since we're currently in the middle of
12573 * a fork we can't be exiting at the same time.
12577 * Lock the parent list. No need to lock the child - not PID
12578 * hashed yet and not running, so nobody can access it.
12580 mutex_lock(&parent_ctx->mutex);
12583 * We dont have to disable NMIs - we are only looking at
12584 * the list, not manipulating it:
12586 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
12587 ret = inherit_task_group(event, parent, parent_ctx,
12588 child, ctxn, &inherited_all);
12594 * We can't hold ctx->lock when iterating the ->flexible_group list due
12595 * to allocations, but we need to prevent rotation because
12596 * rotate_ctx() will change the list from interrupt context.
12598 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12599 parent_ctx->rotate_disable = 1;
12600 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12602 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
12603 ret = inherit_task_group(event, parent, parent_ctx,
12604 child, ctxn, &inherited_all);
12609 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12610 parent_ctx->rotate_disable = 0;
12612 child_ctx = child->perf_event_ctxp[ctxn];
12614 if (child_ctx && inherited_all) {
12616 * Mark the child context as a clone of the parent
12617 * context, or of whatever the parent is a clone of.
12619 * Note that if the parent is a clone, the holding of
12620 * parent_ctx->lock avoids it from being uncloned.
12622 cloned_ctx = parent_ctx->parent_ctx;
12624 child_ctx->parent_ctx = cloned_ctx;
12625 child_ctx->parent_gen = parent_ctx->parent_gen;
12627 child_ctx->parent_ctx = parent_ctx;
12628 child_ctx->parent_gen = parent_ctx->generation;
12630 get_ctx(child_ctx->parent_ctx);
12633 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12635 mutex_unlock(&parent_ctx->mutex);
12637 perf_unpin_context(parent_ctx);
12638 put_ctx(parent_ctx);
12644 * Initialize the perf_event context in task_struct
12646 int perf_event_init_task(struct task_struct *child)
12650 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
12651 mutex_init(&child->perf_event_mutex);
12652 INIT_LIST_HEAD(&child->perf_event_list);
12654 for_each_task_context_nr(ctxn) {
12655 ret = perf_event_init_context(child, ctxn);
12657 perf_event_free_task(child);
12665 static void __init perf_event_init_all_cpus(void)
12667 struct swevent_htable *swhash;
12670 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
12672 for_each_possible_cpu(cpu) {
12673 swhash = &per_cpu(swevent_htable, cpu);
12674 mutex_init(&swhash->hlist_mutex);
12675 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
12677 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
12678 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
12680 #ifdef CONFIG_CGROUP_PERF
12681 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
12683 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
12687 static void perf_swevent_init_cpu(unsigned int cpu)
12689 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
12691 mutex_lock(&swhash->hlist_mutex);
12692 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
12693 struct swevent_hlist *hlist;
12695 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
12697 rcu_assign_pointer(swhash->swevent_hlist, hlist);
12699 mutex_unlock(&swhash->hlist_mutex);
12702 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
12703 static void __perf_event_exit_context(void *__info)
12705 struct perf_event_context *ctx = __info;
12706 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
12707 struct perf_event *event;
12709 raw_spin_lock(&ctx->lock);
12710 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
12711 list_for_each_entry(event, &ctx->event_list, event_entry)
12712 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
12713 raw_spin_unlock(&ctx->lock);
12716 static void perf_event_exit_cpu_context(int cpu)
12718 struct perf_cpu_context *cpuctx;
12719 struct perf_event_context *ctx;
12722 mutex_lock(&pmus_lock);
12723 list_for_each_entry(pmu, &pmus, entry) {
12724 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12725 ctx = &cpuctx->ctx;
12727 mutex_lock(&ctx->mutex);
12728 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
12729 cpuctx->online = 0;
12730 mutex_unlock(&ctx->mutex);
12732 cpumask_clear_cpu(cpu, perf_online_mask);
12733 mutex_unlock(&pmus_lock);
12737 static void perf_event_exit_cpu_context(int cpu) { }
12741 int perf_event_init_cpu(unsigned int cpu)
12743 struct perf_cpu_context *cpuctx;
12744 struct perf_event_context *ctx;
12747 perf_swevent_init_cpu(cpu);
12749 mutex_lock(&pmus_lock);
12750 cpumask_set_cpu(cpu, perf_online_mask);
12751 list_for_each_entry(pmu, &pmus, entry) {
12752 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12753 ctx = &cpuctx->ctx;
12755 mutex_lock(&ctx->mutex);
12756 cpuctx->online = 1;
12757 mutex_unlock(&ctx->mutex);
12759 mutex_unlock(&pmus_lock);
12764 int perf_event_exit_cpu(unsigned int cpu)
12766 perf_event_exit_cpu_context(cpu);
12771 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
12775 for_each_online_cpu(cpu)
12776 perf_event_exit_cpu(cpu);
12782 * Run the perf reboot notifier at the very last possible moment so that
12783 * the generic watchdog code runs as long as possible.
12785 static struct notifier_block perf_reboot_notifier = {
12786 .notifier_call = perf_reboot,
12787 .priority = INT_MIN,
12790 void __init perf_event_init(void)
12794 idr_init(&pmu_idr);
12796 perf_event_init_all_cpus();
12797 init_srcu_struct(&pmus_srcu);
12798 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
12799 perf_pmu_register(&perf_cpu_clock, NULL, -1);
12800 perf_pmu_register(&perf_task_clock, NULL, -1);
12801 perf_tp_register();
12802 perf_event_init_cpu(smp_processor_id());
12803 register_reboot_notifier(&perf_reboot_notifier);
12805 ret = init_hw_breakpoint();
12806 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
12809 * Build time assertion that we keep the data_head at the intended
12810 * location. IOW, validation we got the __reserved[] size right.
12812 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
12816 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
12819 struct perf_pmu_events_attr *pmu_attr =
12820 container_of(attr, struct perf_pmu_events_attr, attr);
12822 if (pmu_attr->event_str)
12823 return sprintf(page, "%s\n", pmu_attr->event_str);
12827 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
12829 static int __init perf_event_sysfs_init(void)
12834 mutex_lock(&pmus_lock);
12836 ret = bus_register(&pmu_bus);
12840 list_for_each_entry(pmu, &pmus, entry) {
12841 if (!pmu->name || pmu->type < 0)
12844 ret = pmu_dev_alloc(pmu);
12845 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
12847 pmu_bus_running = 1;
12851 mutex_unlock(&pmus_lock);
12855 device_initcall(perf_event_sysfs_init);
12857 #ifdef CONFIG_CGROUP_PERF
12858 static struct cgroup_subsys_state *
12859 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
12861 struct perf_cgroup *jc;
12863 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
12865 return ERR_PTR(-ENOMEM);
12867 jc->info = alloc_percpu(struct perf_cgroup_info);
12870 return ERR_PTR(-ENOMEM);
12876 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
12878 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
12880 free_percpu(jc->info);
12884 static int perf_cgroup_css_online(struct cgroup_subsys_state *css)
12886 perf_event_cgroup(css->cgroup);
12890 static int __perf_cgroup_move(void *info)
12892 struct task_struct *task = info;
12894 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
12899 static void perf_cgroup_attach(struct cgroup_taskset *tset)
12901 struct task_struct *task;
12902 struct cgroup_subsys_state *css;
12904 cgroup_taskset_for_each(task, css, tset)
12905 task_function_call(task, __perf_cgroup_move, task);
12908 struct cgroup_subsys perf_event_cgrp_subsys = {
12909 .css_alloc = perf_cgroup_css_alloc,
12910 .css_free = perf_cgroup_css_free,
12911 .css_online = perf_cgroup_css_online,
12912 .attach = perf_cgroup_attach,
12914 * Implicitly enable on dfl hierarchy so that perf events can
12915 * always be filtered by cgroup2 path as long as perf_event
12916 * controller is not mounted on a legacy hierarchy.
12918 .implicit_on_dfl = true,
12921 #endif /* CONFIG_CGROUP_PERF */