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 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
989 struct perf_cpu_context *cpuctx;
991 if (!is_cgroup_event(event))
995 * Because cgroup events are always per-cpu events,
996 * @ctx == &cpuctx->ctx.
998 cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
1001 * Since setting cpuctx->cgrp is conditional on the current @cgrp
1002 * matching the event's cgroup, we must do this for every new event,
1003 * because if the first would mismatch, the second would not try again
1004 * and we would leave cpuctx->cgrp unset.
1006 if (ctx->is_active && !cpuctx->cgrp) {
1007 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
1009 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
1010 cpuctx->cgrp = cgrp;
1013 if (ctx->nr_cgroups++)
1016 list_add(&cpuctx->cgrp_cpuctx_entry,
1017 per_cpu_ptr(&cgrp_cpuctx_list, event->cpu));
1021 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
1023 struct perf_cpu_context *cpuctx;
1025 if (!is_cgroup_event(event))
1029 * Because cgroup events are always per-cpu events,
1030 * @ctx == &cpuctx->ctx.
1032 cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
1034 if (--ctx->nr_cgroups)
1037 if (ctx->is_active && cpuctx->cgrp)
1038 cpuctx->cgrp = NULL;
1040 list_del(&cpuctx->cgrp_cpuctx_entry);
1043 #else /* !CONFIG_CGROUP_PERF */
1046 perf_cgroup_match(struct perf_event *event)
1051 static inline void perf_detach_cgroup(struct perf_event *event)
1054 static inline int is_cgroup_event(struct perf_event *event)
1059 static inline void update_cgrp_time_from_event(struct perf_event *event)
1063 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
1067 static inline void perf_cgroup_sched_out(struct task_struct *task,
1068 struct task_struct *next)
1072 static inline void perf_cgroup_sched_in(struct task_struct *prev,
1073 struct task_struct *task)
1077 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1078 struct perf_event_attr *attr,
1079 struct perf_event *group_leader)
1085 perf_cgroup_set_timestamp(struct task_struct *task,
1086 struct perf_event_context *ctx)
1091 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1096 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1100 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1106 perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
1111 perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
1117 * set default to be dependent on timer tick just
1118 * like original code
1120 #define PERF_CPU_HRTIMER (1000 / HZ)
1122 * function must be called with interrupts disabled
1124 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1126 struct perf_cpu_context *cpuctx;
1129 lockdep_assert_irqs_disabled();
1131 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1132 rotations = perf_rotate_context(cpuctx);
1134 raw_spin_lock(&cpuctx->hrtimer_lock);
1136 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1138 cpuctx->hrtimer_active = 0;
1139 raw_spin_unlock(&cpuctx->hrtimer_lock);
1141 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1144 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1146 struct hrtimer *timer = &cpuctx->hrtimer;
1147 struct pmu *pmu = cpuctx->ctx.pmu;
1150 /* no multiplexing needed for SW PMU */
1151 if (pmu->task_ctx_nr == perf_sw_context)
1155 * check default is sane, if not set then force to
1156 * default interval (1/tick)
1158 interval = pmu->hrtimer_interval_ms;
1160 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1162 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1164 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1165 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
1166 timer->function = perf_mux_hrtimer_handler;
1169 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1171 struct hrtimer *timer = &cpuctx->hrtimer;
1172 struct pmu *pmu = cpuctx->ctx.pmu;
1173 unsigned long flags;
1175 /* not for SW PMU */
1176 if (pmu->task_ctx_nr == perf_sw_context)
1179 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1180 if (!cpuctx->hrtimer_active) {
1181 cpuctx->hrtimer_active = 1;
1182 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1183 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
1185 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1190 void perf_pmu_disable(struct pmu *pmu)
1192 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1194 pmu->pmu_disable(pmu);
1197 void perf_pmu_enable(struct pmu *pmu)
1199 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1201 pmu->pmu_enable(pmu);
1204 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1207 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1208 * perf_event_task_tick() are fully serialized because they're strictly cpu
1209 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1210 * disabled, while perf_event_task_tick is called from IRQ context.
1212 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1214 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1216 lockdep_assert_irqs_disabled();
1218 WARN_ON(!list_empty(&ctx->active_ctx_list));
1220 list_add(&ctx->active_ctx_list, head);
1223 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1225 lockdep_assert_irqs_disabled();
1227 WARN_ON(list_empty(&ctx->active_ctx_list));
1229 list_del_init(&ctx->active_ctx_list);
1232 static void get_ctx(struct perf_event_context *ctx)
1234 refcount_inc(&ctx->refcount);
1237 static void free_ctx(struct rcu_head *head)
1239 struct perf_event_context *ctx;
1241 ctx = container_of(head, struct perf_event_context, rcu_head);
1242 kfree(ctx->task_ctx_data);
1246 static void put_ctx(struct perf_event_context *ctx)
1248 if (refcount_dec_and_test(&ctx->refcount)) {
1249 if (ctx->parent_ctx)
1250 put_ctx(ctx->parent_ctx);
1251 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1252 put_task_struct(ctx->task);
1253 call_rcu(&ctx->rcu_head, free_ctx);
1258 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1259 * perf_pmu_migrate_context() we need some magic.
1261 * Those places that change perf_event::ctx will hold both
1262 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1264 * Lock ordering is by mutex address. There are two other sites where
1265 * perf_event_context::mutex nests and those are:
1267 * - perf_event_exit_task_context() [ child , 0 ]
1268 * perf_event_exit_event()
1269 * put_event() [ parent, 1 ]
1271 * - perf_event_init_context() [ parent, 0 ]
1272 * inherit_task_group()
1275 * perf_event_alloc()
1277 * perf_try_init_event() [ child , 1 ]
1279 * While it appears there is an obvious deadlock here -- the parent and child
1280 * nesting levels are inverted between the two. This is in fact safe because
1281 * life-time rules separate them. That is an exiting task cannot fork, and a
1282 * spawning task cannot (yet) exit.
1284 * But remember that that these are parent<->child context relations, and
1285 * migration does not affect children, therefore these two orderings should not
1288 * The change in perf_event::ctx does not affect children (as claimed above)
1289 * because the sys_perf_event_open() case will install a new event and break
1290 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1291 * concerned with cpuctx and that doesn't have children.
1293 * The places that change perf_event::ctx will issue:
1295 * perf_remove_from_context();
1296 * synchronize_rcu();
1297 * perf_install_in_context();
1299 * to affect the change. The remove_from_context() + synchronize_rcu() should
1300 * quiesce the event, after which we can install it in the new location. This
1301 * means that only external vectors (perf_fops, prctl) can perturb the event
1302 * while in transit. Therefore all such accessors should also acquire
1303 * perf_event_context::mutex to serialize against this.
1305 * However; because event->ctx can change while we're waiting to acquire
1306 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1311 * task_struct::perf_event_mutex
1312 * perf_event_context::mutex
1313 * perf_event::child_mutex;
1314 * perf_event_context::lock
1315 * perf_event::mmap_mutex
1317 * perf_addr_filters_head::lock
1321 * cpuctx->mutex / perf_event_context::mutex
1323 static struct perf_event_context *
1324 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1326 struct perf_event_context *ctx;
1330 ctx = READ_ONCE(event->ctx);
1331 if (!refcount_inc_not_zero(&ctx->refcount)) {
1337 mutex_lock_nested(&ctx->mutex, nesting);
1338 if (event->ctx != ctx) {
1339 mutex_unlock(&ctx->mutex);
1347 static inline struct perf_event_context *
1348 perf_event_ctx_lock(struct perf_event *event)
1350 return perf_event_ctx_lock_nested(event, 0);
1353 static void perf_event_ctx_unlock(struct perf_event *event,
1354 struct perf_event_context *ctx)
1356 mutex_unlock(&ctx->mutex);
1361 * This must be done under the ctx->lock, such as to serialize against
1362 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1363 * calling scheduler related locks and ctx->lock nests inside those.
1365 static __must_check struct perf_event_context *
1366 unclone_ctx(struct perf_event_context *ctx)
1368 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1370 lockdep_assert_held(&ctx->lock);
1373 ctx->parent_ctx = NULL;
1379 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1384 * only top level events have the pid namespace they were created in
1387 event = event->parent;
1389 nr = __task_pid_nr_ns(p, type, event->ns);
1390 /* avoid -1 if it is idle thread or runs in another ns */
1391 if (!nr && !pid_alive(p))
1396 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1398 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1401 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1403 return perf_event_pid_type(event, p, PIDTYPE_PID);
1407 * If we inherit events we want to return the parent event id
1410 static u64 primary_event_id(struct perf_event *event)
1415 id = event->parent->id;
1421 * Get the perf_event_context for a task and lock it.
1423 * This has to cope with with the fact that until it is locked,
1424 * the context could get moved to another task.
1426 static struct perf_event_context *
1427 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1429 struct perf_event_context *ctx;
1433 * One of the few rules of preemptible RCU is that one cannot do
1434 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1435 * part of the read side critical section was irqs-enabled -- see
1436 * rcu_read_unlock_special().
1438 * Since ctx->lock nests under rq->lock we must ensure the entire read
1439 * side critical section has interrupts disabled.
1441 local_irq_save(*flags);
1443 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1446 * If this context is a clone of another, it might
1447 * get swapped for another underneath us by
1448 * perf_event_task_sched_out, though the
1449 * rcu_read_lock() protects us from any context
1450 * getting freed. Lock the context and check if it
1451 * got swapped before we could get the lock, and retry
1452 * if so. If we locked the right context, then it
1453 * can't get swapped on us any more.
1455 raw_spin_lock(&ctx->lock);
1456 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1457 raw_spin_unlock(&ctx->lock);
1459 local_irq_restore(*flags);
1463 if (ctx->task == TASK_TOMBSTONE ||
1464 !refcount_inc_not_zero(&ctx->refcount)) {
1465 raw_spin_unlock(&ctx->lock);
1468 WARN_ON_ONCE(ctx->task != task);
1473 local_irq_restore(*flags);
1478 * Get the context for a task and increment its pin_count so it
1479 * can't get swapped to another task. This also increments its
1480 * reference count so that the context can't get freed.
1482 static struct perf_event_context *
1483 perf_pin_task_context(struct task_struct *task, int ctxn)
1485 struct perf_event_context *ctx;
1486 unsigned long flags;
1488 ctx = perf_lock_task_context(task, ctxn, &flags);
1491 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1496 static void perf_unpin_context(struct perf_event_context *ctx)
1498 unsigned long flags;
1500 raw_spin_lock_irqsave(&ctx->lock, flags);
1502 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1506 * Update the record of the current time in a context.
1508 static void update_context_time(struct perf_event_context *ctx)
1510 u64 now = perf_clock();
1512 ctx->time += now - ctx->timestamp;
1513 ctx->timestamp = now;
1516 static u64 perf_event_time(struct perf_event *event)
1518 struct perf_event_context *ctx = event->ctx;
1520 if (is_cgroup_event(event))
1521 return perf_cgroup_event_time(event);
1523 return ctx ? ctx->time : 0;
1526 static enum event_type_t get_event_type(struct perf_event *event)
1528 struct perf_event_context *ctx = event->ctx;
1529 enum event_type_t event_type;
1531 lockdep_assert_held(&ctx->lock);
1534 * It's 'group type', really, because if our group leader is
1535 * pinned, so are we.
1537 if (event->group_leader != event)
1538 event = event->group_leader;
1540 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1542 event_type |= EVENT_CPU;
1548 * Helper function to initialize event group nodes.
1550 static void init_event_group(struct perf_event *event)
1552 RB_CLEAR_NODE(&event->group_node);
1553 event->group_index = 0;
1557 * Extract pinned or flexible groups from the context
1558 * based on event attrs bits.
1560 static struct perf_event_groups *
1561 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1563 if (event->attr.pinned)
1564 return &ctx->pinned_groups;
1566 return &ctx->flexible_groups;
1570 * Helper function to initializes perf_event_group trees.
1572 static void perf_event_groups_init(struct perf_event_groups *groups)
1574 groups->tree = RB_ROOT;
1579 * Compare function for event groups;
1581 * Implements complex key that first sorts by CPU and then by virtual index
1582 * which provides ordering when rotating groups for the same CPU.
1585 perf_event_groups_less(struct perf_event *left, struct perf_event *right)
1587 if (left->cpu < right->cpu)
1589 if (left->cpu > right->cpu)
1592 #ifdef CONFIG_CGROUP_PERF
1593 if (left->cgrp != right->cgrp) {
1594 if (!left->cgrp || !left->cgrp->css.cgroup) {
1596 * Left has no cgroup but right does, no cgroups come
1601 if (!right->cgrp || !right->cgrp->css.cgroup) {
1603 * Right has no cgroup but left does, no cgroups come
1608 /* Two dissimilar cgroups, order by id. */
1609 if (left->cgrp->css.cgroup->kn->id < right->cgrp->css.cgroup->kn->id)
1616 if (left->group_index < right->group_index)
1618 if (left->group_index > right->group_index)
1625 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1626 * key (see perf_event_groups_less). This places it last inside the CPU
1630 perf_event_groups_insert(struct perf_event_groups *groups,
1631 struct perf_event *event)
1633 struct perf_event *node_event;
1634 struct rb_node *parent;
1635 struct rb_node **node;
1637 event->group_index = ++groups->index;
1639 node = &groups->tree.rb_node;
1644 node_event = container_of(*node, struct perf_event, group_node);
1646 if (perf_event_groups_less(event, node_event))
1647 node = &parent->rb_left;
1649 node = &parent->rb_right;
1652 rb_link_node(&event->group_node, parent, node);
1653 rb_insert_color(&event->group_node, &groups->tree);
1657 * Helper function to insert event into the pinned or flexible groups.
1660 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1662 struct perf_event_groups *groups;
1664 groups = get_event_groups(event, ctx);
1665 perf_event_groups_insert(groups, event);
1669 * Delete a group from a tree.
1672 perf_event_groups_delete(struct perf_event_groups *groups,
1673 struct perf_event *event)
1675 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1676 RB_EMPTY_ROOT(&groups->tree));
1678 rb_erase(&event->group_node, &groups->tree);
1679 init_event_group(event);
1683 * Helper function to delete event from its groups.
1686 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1688 struct perf_event_groups *groups;
1690 groups = get_event_groups(event, ctx);
1691 perf_event_groups_delete(groups, event);
1695 * Get the leftmost event in the cpu/cgroup subtree.
1697 static struct perf_event *
1698 perf_event_groups_first(struct perf_event_groups *groups, int cpu,
1699 struct cgroup *cgrp)
1701 struct perf_event *node_event = NULL, *match = NULL;
1702 struct rb_node *node = groups->tree.rb_node;
1703 #ifdef CONFIG_CGROUP_PERF
1704 u64 node_cgrp_id, cgrp_id = 0;
1707 cgrp_id = cgrp->kn->id;
1711 node_event = container_of(node, struct perf_event, group_node);
1713 if (cpu < node_event->cpu) {
1714 node = node->rb_left;
1717 if (cpu > node_event->cpu) {
1718 node = node->rb_right;
1721 #ifdef CONFIG_CGROUP_PERF
1723 if (node_event->cgrp && node_event->cgrp->css.cgroup)
1724 node_cgrp_id = node_event->cgrp->css.cgroup->kn->id;
1726 if (cgrp_id < node_cgrp_id) {
1727 node = node->rb_left;
1730 if (cgrp_id > node_cgrp_id) {
1731 node = node->rb_right;
1736 node = node->rb_left;
1743 * Like rb_entry_next_safe() for the @cpu subtree.
1745 static struct perf_event *
1746 perf_event_groups_next(struct perf_event *event)
1748 struct perf_event *next;
1749 #ifdef CONFIG_CGROUP_PERF
1750 u64 curr_cgrp_id = 0;
1751 u64 next_cgrp_id = 0;
1754 next = rb_entry_safe(rb_next(&event->group_node), typeof(*event), group_node);
1755 if (next == NULL || next->cpu != event->cpu)
1758 #ifdef CONFIG_CGROUP_PERF
1759 if (event->cgrp && event->cgrp->css.cgroup)
1760 curr_cgrp_id = event->cgrp->css.cgroup->kn->id;
1762 if (next->cgrp && next->cgrp->css.cgroup)
1763 next_cgrp_id = next->cgrp->css.cgroup->kn->id;
1765 if (curr_cgrp_id != next_cgrp_id)
1772 * Iterate through the whole groups tree.
1774 #define perf_event_groups_for_each(event, groups) \
1775 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1776 typeof(*event), group_node); event; \
1777 event = rb_entry_safe(rb_next(&event->group_node), \
1778 typeof(*event), group_node))
1781 * Add an event from the lists for its context.
1782 * Must be called with ctx->mutex and ctx->lock held.
1785 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1787 lockdep_assert_held(&ctx->lock);
1789 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1790 event->attach_state |= PERF_ATTACH_CONTEXT;
1792 event->tstamp = perf_event_time(event);
1795 * If we're a stand alone event or group leader, we go to the context
1796 * list, group events are kept attached to the group so that
1797 * perf_group_detach can, at all times, locate all siblings.
1799 if (event->group_leader == event) {
1800 event->group_caps = event->event_caps;
1801 add_event_to_groups(event, ctx);
1804 list_add_rcu(&event->event_entry, &ctx->event_list);
1806 if (event->attr.inherit_stat)
1809 if (event->state > PERF_EVENT_STATE_OFF)
1810 perf_cgroup_event_enable(event, ctx);
1816 * Initialize event state based on the perf_event_attr::disabled.
1818 static inline void perf_event__state_init(struct perf_event *event)
1820 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1821 PERF_EVENT_STATE_INACTIVE;
1824 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1826 int entry = sizeof(u64); /* value */
1830 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1831 size += sizeof(u64);
1833 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1834 size += sizeof(u64);
1836 if (event->attr.read_format & PERF_FORMAT_ID)
1837 entry += sizeof(u64);
1839 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1841 size += sizeof(u64);
1845 event->read_size = size;
1848 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1850 struct perf_sample_data *data;
1853 if (sample_type & PERF_SAMPLE_IP)
1854 size += sizeof(data->ip);
1856 if (sample_type & PERF_SAMPLE_ADDR)
1857 size += sizeof(data->addr);
1859 if (sample_type & PERF_SAMPLE_PERIOD)
1860 size += sizeof(data->period);
1862 if (sample_type & PERF_SAMPLE_WEIGHT)
1863 size += sizeof(data->weight);
1865 if (sample_type & PERF_SAMPLE_READ)
1866 size += event->read_size;
1868 if (sample_type & PERF_SAMPLE_DATA_SRC)
1869 size += sizeof(data->data_src.val);
1871 if (sample_type & PERF_SAMPLE_TRANSACTION)
1872 size += sizeof(data->txn);
1874 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1875 size += sizeof(data->phys_addr);
1877 if (sample_type & PERF_SAMPLE_CGROUP)
1878 size += sizeof(data->cgroup);
1880 event->header_size = size;
1884 * Called at perf_event creation and when events are attached/detached from a
1887 static void perf_event__header_size(struct perf_event *event)
1889 __perf_event_read_size(event,
1890 event->group_leader->nr_siblings);
1891 __perf_event_header_size(event, event->attr.sample_type);
1894 static void perf_event__id_header_size(struct perf_event *event)
1896 struct perf_sample_data *data;
1897 u64 sample_type = event->attr.sample_type;
1900 if (sample_type & PERF_SAMPLE_TID)
1901 size += sizeof(data->tid_entry);
1903 if (sample_type & PERF_SAMPLE_TIME)
1904 size += sizeof(data->time);
1906 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1907 size += sizeof(data->id);
1909 if (sample_type & PERF_SAMPLE_ID)
1910 size += sizeof(data->id);
1912 if (sample_type & PERF_SAMPLE_STREAM_ID)
1913 size += sizeof(data->stream_id);
1915 if (sample_type & PERF_SAMPLE_CPU)
1916 size += sizeof(data->cpu_entry);
1918 event->id_header_size = size;
1921 static bool perf_event_validate_size(struct perf_event *event)
1924 * The values computed here will be over-written when we actually
1927 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1928 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1929 perf_event__id_header_size(event);
1932 * Sum the lot; should not exceed the 64k limit we have on records.
1933 * Conservative limit to allow for callchains and other variable fields.
1935 if (event->read_size + event->header_size +
1936 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1942 static void perf_group_attach(struct perf_event *event)
1944 struct perf_event *group_leader = event->group_leader, *pos;
1946 lockdep_assert_held(&event->ctx->lock);
1949 * We can have double attach due to group movement in perf_event_open.
1951 if (event->attach_state & PERF_ATTACH_GROUP)
1954 event->attach_state |= PERF_ATTACH_GROUP;
1956 if (group_leader == event)
1959 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1961 group_leader->group_caps &= event->event_caps;
1963 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1964 group_leader->nr_siblings++;
1966 perf_event__header_size(group_leader);
1968 for_each_sibling_event(pos, group_leader)
1969 perf_event__header_size(pos);
1973 * Remove an event from the lists for its context.
1974 * Must be called with ctx->mutex and ctx->lock held.
1977 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1979 WARN_ON_ONCE(event->ctx != ctx);
1980 lockdep_assert_held(&ctx->lock);
1983 * We can have double detach due to exit/hot-unplug + close.
1985 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1988 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1991 if (event->attr.inherit_stat)
1994 list_del_rcu(&event->event_entry);
1996 if (event->group_leader == event)
1997 del_event_from_groups(event, ctx);
2000 * If event was in error state, then keep it
2001 * that way, otherwise bogus counts will be
2002 * returned on read(). The only way to get out
2003 * of error state is by explicit re-enabling
2006 if (event->state > PERF_EVENT_STATE_OFF) {
2007 perf_cgroup_event_disable(event, ctx);
2008 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2015 perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
2017 if (!has_aux(aux_event))
2020 if (!event->pmu->aux_output_match)
2023 return event->pmu->aux_output_match(aux_event);
2026 static void put_event(struct perf_event *event);
2027 static void event_sched_out(struct perf_event *event,
2028 struct perf_cpu_context *cpuctx,
2029 struct perf_event_context *ctx);
2031 static void perf_put_aux_event(struct perf_event *event)
2033 struct perf_event_context *ctx = event->ctx;
2034 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2035 struct perf_event *iter;
2038 * If event uses aux_event tear down the link
2040 if (event->aux_event) {
2041 iter = event->aux_event;
2042 event->aux_event = NULL;
2048 * If the event is an aux_event, tear down all links to
2049 * it from other events.
2051 for_each_sibling_event(iter, event->group_leader) {
2052 if (iter->aux_event != event)
2055 iter->aux_event = NULL;
2059 * If it's ACTIVE, schedule it out and put it into ERROR
2060 * state so that we don't try to schedule it again. Note
2061 * that perf_event_enable() will clear the ERROR status.
2063 event_sched_out(iter, cpuctx, ctx);
2064 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2068 static bool perf_need_aux_event(struct perf_event *event)
2070 return !!event->attr.aux_output || !!event->attr.aux_sample_size;
2073 static int perf_get_aux_event(struct perf_event *event,
2074 struct perf_event *group_leader)
2077 * Our group leader must be an aux event if we want to be
2078 * an aux_output. This way, the aux event will precede its
2079 * aux_output events in the group, and therefore will always
2086 * aux_output and aux_sample_size are mutually exclusive.
2088 if (event->attr.aux_output && event->attr.aux_sample_size)
2091 if (event->attr.aux_output &&
2092 !perf_aux_output_match(event, group_leader))
2095 if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux)
2098 if (!atomic_long_inc_not_zero(&group_leader->refcount))
2102 * Link aux_outputs to their aux event; this is undone in
2103 * perf_group_detach() by perf_put_aux_event(). When the
2104 * group in torn down, the aux_output events loose their
2105 * link to the aux_event and can't schedule any more.
2107 event->aux_event = group_leader;
2112 static inline struct list_head *get_event_list(struct perf_event *event)
2114 struct perf_event_context *ctx = event->ctx;
2115 return event->attr.pinned ? &ctx->pinned_active : &ctx->flexible_active;
2118 static void perf_group_detach(struct perf_event *event)
2120 struct perf_event *sibling, *tmp;
2121 struct perf_event_context *ctx = event->ctx;
2123 lockdep_assert_held(&ctx->lock);
2126 * We can have double detach due to exit/hot-unplug + close.
2128 if (!(event->attach_state & PERF_ATTACH_GROUP))
2131 event->attach_state &= ~PERF_ATTACH_GROUP;
2133 perf_put_aux_event(event);
2136 * If this is a sibling, remove it from its group.
2138 if (event->group_leader != event) {
2139 list_del_init(&event->sibling_list);
2140 event->group_leader->nr_siblings--;
2145 * If this was a group event with sibling events then
2146 * upgrade the siblings to singleton events by adding them
2147 * to whatever list we are on.
2149 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
2151 sibling->group_leader = sibling;
2152 list_del_init(&sibling->sibling_list);
2154 /* Inherit group flags from the previous leader */
2155 sibling->group_caps = event->group_caps;
2157 if (!RB_EMPTY_NODE(&event->group_node)) {
2158 add_event_to_groups(sibling, event->ctx);
2160 if (sibling->state == PERF_EVENT_STATE_ACTIVE)
2161 list_add_tail(&sibling->active_list, get_event_list(sibling));
2164 WARN_ON_ONCE(sibling->ctx != event->ctx);
2168 perf_event__header_size(event->group_leader);
2170 for_each_sibling_event(tmp, event->group_leader)
2171 perf_event__header_size(tmp);
2174 static bool is_orphaned_event(struct perf_event *event)
2176 return event->state == PERF_EVENT_STATE_DEAD;
2179 static inline int __pmu_filter_match(struct perf_event *event)
2181 struct pmu *pmu = event->pmu;
2182 return pmu->filter_match ? pmu->filter_match(event) : 1;
2186 * Check whether we should attempt to schedule an event group based on
2187 * PMU-specific filtering. An event group can consist of HW and SW events,
2188 * potentially with a SW leader, so we must check all the filters, to
2189 * determine whether a group is schedulable:
2191 static inline int pmu_filter_match(struct perf_event *event)
2193 struct perf_event *sibling;
2195 if (!__pmu_filter_match(event))
2198 for_each_sibling_event(sibling, event) {
2199 if (!__pmu_filter_match(sibling))
2207 event_filter_match(struct perf_event *event)
2209 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2210 perf_cgroup_match(event) && pmu_filter_match(event);
2214 event_sched_out(struct perf_event *event,
2215 struct perf_cpu_context *cpuctx,
2216 struct perf_event_context *ctx)
2218 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2220 WARN_ON_ONCE(event->ctx != ctx);
2221 lockdep_assert_held(&ctx->lock);
2223 if (event->state != PERF_EVENT_STATE_ACTIVE)
2227 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2228 * we can schedule events _OUT_ individually through things like
2229 * __perf_remove_from_context().
2231 list_del_init(&event->active_list);
2233 perf_pmu_disable(event->pmu);
2235 event->pmu->del(event, 0);
2238 if (READ_ONCE(event->pending_disable) >= 0) {
2239 WRITE_ONCE(event->pending_disable, -1);
2240 perf_cgroup_event_disable(event, ctx);
2241 state = PERF_EVENT_STATE_OFF;
2243 perf_event_set_state(event, state);
2245 if (!is_software_event(event))
2246 cpuctx->active_oncpu--;
2247 if (!--ctx->nr_active)
2248 perf_event_ctx_deactivate(ctx);
2249 if (event->attr.freq && event->attr.sample_freq)
2251 if (event->attr.exclusive || !cpuctx->active_oncpu)
2252 cpuctx->exclusive = 0;
2254 perf_pmu_enable(event->pmu);
2258 group_sched_out(struct perf_event *group_event,
2259 struct perf_cpu_context *cpuctx,
2260 struct perf_event_context *ctx)
2262 struct perf_event *event;
2264 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2267 perf_pmu_disable(ctx->pmu);
2269 event_sched_out(group_event, cpuctx, ctx);
2272 * Schedule out siblings (if any):
2274 for_each_sibling_event(event, group_event)
2275 event_sched_out(event, cpuctx, ctx);
2277 perf_pmu_enable(ctx->pmu);
2279 if (group_event->attr.exclusive)
2280 cpuctx->exclusive = 0;
2283 #define DETACH_GROUP 0x01UL
2286 * Cross CPU call to remove a performance event
2288 * We disable the event on the hardware level first. After that we
2289 * remove it from the context list.
2292 __perf_remove_from_context(struct perf_event *event,
2293 struct perf_cpu_context *cpuctx,
2294 struct perf_event_context *ctx,
2297 unsigned long flags = (unsigned long)info;
2299 if (ctx->is_active & EVENT_TIME) {
2300 update_context_time(ctx);
2301 update_cgrp_time_from_cpuctx(cpuctx);
2304 event_sched_out(event, cpuctx, ctx);
2305 if (flags & DETACH_GROUP)
2306 perf_group_detach(event);
2307 list_del_event(event, ctx);
2309 if (!ctx->nr_events && ctx->is_active) {
2311 ctx->rotate_necessary = 0;
2313 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2314 cpuctx->task_ctx = NULL;
2320 * Remove the event from a task's (or a CPU's) list of events.
2322 * If event->ctx is a cloned context, callers must make sure that
2323 * every task struct that event->ctx->task could possibly point to
2324 * remains valid. This is OK when called from perf_release since
2325 * that only calls us on the top-level context, which can't be a clone.
2326 * When called from perf_event_exit_task, it's OK because the
2327 * context has been detached from its task.
2329 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2331 struct perf_event_context *ctx = event->ctx;
2333 lockdep_assert_held(&ctx->mutex);
2335 event_function_call(event, __perf_remove_from_context, (void *)flags);
2338 * The above event_function_call() can NO-OP when it hits
2339 * TASK_TOMBSTONE. In that case we must already have been detached
2340 * from the context (by perf_event_exit_event()) but the grouping
2341 * might still be in-tact.
2343 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
2344 if ((flags & DETACH_GROUP) &&
2345 (event->attach_state & PERF_ATTACH_GROUP)) {
2347 * Since in that case we cannot possibly be scheduled, simply
2350 raw_spin_lock_irq(&ctx->lock);
2351 perf_group_detach(event);
2352 raw_spin_unlock_irq(&ctx->lock);
2357 * Cross CPU call to disable a performance event
2359 static void __perf_event_disable(struct perf_event *event,
2360 struct perf_cpu_context *cpuctx,
2361 struct perf_event_context *ctx,
2364 if (event->state < PERF_EVENT_STATE_INACTIVE)
2367 if (ctx->is_active & EVENT_TIME) {
2368 update_context_time(ctx);
2369 update_cgrp_time_from_event(event);
2372 if (event == event->group_leader)
2373 group_sched_out(event, cpuctx, ctx);
2375 event_sched_out(event, cpuctx, ctx);
2377 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2378 perf_cgroup_event_disable(event, ctx);
2384 * If event->ctx is a cloned context, callers must make sure that
2385 * every task struct that event->ctx->task could possibly point to
2386 * remains valid. This condition is satisfied when called through
2387 * perf_event_for_each_child or perf_event_for_each because they
2388 * hold the top-level event's child_mutex, so any descendant that
2389 * goes to exit will block in perf_event_exit_event().
2391 * When called from perf_pending_event it's OK because event->ctx
2392 * is the current context on this CPU and preemption is disabled,
2393 * hence we can't get into perf_event_task_sched_out for this context.
2395 static void _perf_event_disable(struct perf_event *event)
2397 struct perf_event_context *ctx = event->ctx;
2399 raw_spin_lock_irq(&ctx->lock);
2400 if (event->state <= PERF_EVENT_STATE_OFF) {
2401 raw_spin_unlock_irq(&ctx->lock);
2404 raw_spin_unlock_irq(&ctx->lock);
2406 event_function_call(event, __perf_event_disable, NULL);
2409 void perf_event_disable_local(struct perf_event *event)
2411 event_function_local(event, __perf_event_disable, NULL);
2415 * Strictly speaking kernel users cannot create groups and therefore this
2416 * interface does not need the perf_event_ctx_lock() magic.
2418 void perf_event_disable(struct perf_event *event)
2420 struct perf_event_context *ctx;
2422 ctx = perf_event_ctx_lock(event);
2423 _perf_event_disable(event);
2424 perf_event_ctx_unlock(event, ctx);
2426 EXPORT_SYMBOL_GPL(perf_event_disable);
2428 void perf_event_disable_inatomic(struct perf_event *event)
2430 WRITE_ONCE(event->pending_disable, smp_processor_id());
2431 /* can fail, see perf_pending_event_disable() */
2432 irq_work_queue(&event->pending);
2435 static void perf_set_shadow_time(struct perf_event *event,
2436 struct perf_event_context *ctx)
2439 * use the correct time source for the time snapshot
2441 * We could get by without this by leveraging the
2442 * fact that to get to this function, the caller
2443 * has most likely already called update_context_time()
2444 * and update_cgrp_time_xx() and thus both timestamp
2445 * are identical (or very close). Given that tstamp is,
2446 * already adjusted for cgroup, we could say that:
2447 * tstamp - ctx->timestamp
2449 * tstamp - cgrp->timestamp.
2451 * Then, in perf_output_read(), the calculation would
2452 * work with no changes because:
2453 * - event is guaranteed scheduled in
2454 * - no scheduled out in between
2455 * - thus the timestamp would be the same
2457 * But this is a bit hairy.
2459 * So instead, we have an explicit cgroup call to remain
2460 * within the time time source all along. We believe it
2461 * is cleaner and simpler to understand.
2463 if (is_cgroup_event(event))
2464 perf_cgroup_set_shadow_time(event, event->tstamp);
2466 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2469 #define MAX_INTERRUPTS (~0ULL)
2471 static void perf_log_throttle(struct perf_event *event, int enable);
2472 static void perf_log_itrace_start(struct perf_event *event);
2475 event_sched_in(struct perf_event *event,
2476 struct perf_cpu_context *cpuctx,
2477 struct perf_event_context *ctx)
2481 WARN_ON_ONCE(event->ctx != ctx);
2483 lockdep_assert_held(&ctx->lock);
2485 if (event->state <= PERF_EVENT_STATE_OFF)
2488 WRITE_ONCE(event->oncpu, smp_processor_id());
2490 * Order event::oncpu write to happen before the ACTIVE state is
2491 * visible. This allows perf_event_{stop,read}() to observe the correct
2492 * ->oncpu if it sees ACTIVE.
2495 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2498 * Unthrottle events, since we scheduled we might have missed several
2499 * ticks already, also for a heavily scheduling task there is little
2500 * guarantee it'll get a tick in a timely manner.
2502 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2503 perf_log_throttle(event, 1);
2504 event->hw.interrupts = 0;
2507 perf_pmu_disable(event->pmu);
2509 perf_set_shadow_time(event, ctx);
2511 perf_log_itrace_start(event);
2513 if (event->pmu->add(event, PERF_EF_START)) {
2514 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2520 if (!is_software_event(event))
2521 cpuctx->active_oncpu++;
2522 if (!ctx->nr_active++)
2523 perf_event_ctx_activate(ctx);
2524 if (event->attr.freq && event->attr.sample_freq)
2527 if (event->attr.exclusive)
2528 cpuctx->exclusive = 1;
2531 perf_pmu_enable(event->pmu);
2537 group_sched_in(struct perf_event *group_event,
2538 struct perf_cpu_context *cpuctx,
2539 struct perf_event_context *ctx)
2541 struct perf_event *event, *partial_group = NULL;
2542 struct pmu *pmu = ctx->pmu;
2544 if (group_event->state == PERF_EVENT_STATE_OFF)
2547 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2549 if (event_sched_in(group_event, cpuctx, ctx)) {
2550 pmu->cancel_txn(pmu);
2551 perf_mux_hrtimer_restart(cpuctx);
2556 * Schedule in siblings as one group (if any):
2558 for_each_sibling_event(event, group_event) {
2559 if (event_sched_in(event, cpuctx, ctx)) {
2560 partial_group = event;
2565 if (!pmu->commit_txn(pmu))
2570 * Groups can be scheduled in as one unit only, so undo any
2571 * partial group before returning:
2572 * The events up to the failed event are scheduled out normally.
2574 for_each_sibling_event(event, group_event) {
2575 if (event == partial_group)
2578 event_sched_out(event, cpuctx, ctx);
2580 event_sched_out(group_event, cpuctx, ctx);
2582 pmu->cancel_txn(pmu);
2584 perf_mux_hrtimer_restart(cpuctx);
2590 * Work out whether we can put this event group on the CPU now.
2592 static int group_can_go_on(struct perf_event *event,
2593 struct perf_cpu_context *cpuctx,
2597 * Groups consisting entirely of software events can always go on.
2599 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2602 * If an exclusive group is already on, no other hardware
2605 if (cpuctx->exclusive)
2608 * If this group is exclusive and there are already
2609 * events on the CPU, it can't go on.
2611 if (event->attr.exclusive && cpuctx->active_oncpu)
2614 * Otherwise, try to add it if all previous groups were able
2620 static void add_event_to_ctx(struct perf_event *event,
2621 struct perf_event_context *ctx)
2623 list_add_event(event, ctx);
2624 perf_group_attach(event);
2627 static void ctx_sched_out(struct perf_event_context *ctx,
2628 struct perf_cpu_context *cpuctx,
2629 enum event_type_t event_type);
2631 ctx_sched_in(struct perf_event_context *ctx,
2632 struct perf_cpu_context *cpuctx,
2633 enum event_type_t event_type,
2634 struct task_struct *task);
2636 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2637 struct perf_event_context *ctx,
2638 enum event_type_t event_type)
2640 if (!cpuctx->task_ctx)
2643 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2646 ctx_sched_out(ctx, cpuctx, event_type);
2649 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2650 struct perf_event_context *ctx,
2651 struct task_struct *task)
2653 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2655 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2656 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2658 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2662 * We want to maintain the following priority of scheduling:
2663 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2664 * - task pinned (EVENT_PINNED)
2665 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2666 * - task flexible (EVENT_FLEXIBLE).
2668 * In order to avoid unscheduling and scheduling back in everything every
2669 * time an event is added, only do it for the groups of equal priority and
2672 * This can be called after a batch operation on task events, in which case
2673 * event_type is a bit mask of the types of events involved. For CPU events,
2674 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2676 static void ctx_resched(struct perf_cpu_context *cpuctx,
2677 struct perf_event_context *task_ctx,
2678 enum event_type_t event_type)
2680 enum event_type_t ctx_event_type;
2681 bool cpu_event = !!(event_type & EVENT_CPU);
2684 * If pinned groups are involved, flexible groups also need to be
2687 if (event_type & EVENT_PINNED)
2688 event_type |= EVENT_FLEXIBLE;
2690 ctx_event_type = event_type & EVENT_ALL;
2692 perf_pmu_disable(cpuctx->ctx.pmu);
2694 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2697 * Decide which cpu ctx groups to schedule out based on the types
2698 * of events that caused rescheduling:
2699 * - EVENT_CPU: schedule out corresponding groups;
2700 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2701 * - otherwise, do nothing more.
2704 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2705 else if (ctx_event_type & EVENT_PINNED)
2706 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2708 perf_event_sched_in(cpuctx, task_ctx, current);
2709 perf_pmu_enable(cpuctx->ctx.pmu);
2712 void perf_pmu_resched(struct pmu *pmu)
2714 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2715 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2717 perf_ctx_lock(cpuctx, task_ctx);
2718 ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2719 perf_ctx_unlock(cpuctx, task_ctx);
2723 * Cross CPU call to install and enable a performance event
2725 * Very similar to remote_function() + event_function() but cannot assume that
2726 * things like ctx->is_active and cpuctx->task_ctx are set.
2728 static int __perf_install_in_context(void *info)
2730 struct perf_event *event = info;
2731 struct perf_event_context *ctx = event->ctx;
2732 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2733 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2734 bool reprogram = true;
2737 raw_spin_lock(&cpuctx->ctx.lock);
2739 raw_spin_lock(&ctx->lock);
2742 reprogram = (ctx->task == current);
2745 * If the task is running, it must be running on this CPU,
2746 * otherwise we cannot reprogram things.
2748 * If its not running, we don't care, ctx->lock will
2749 * serialize against it becoming runnable.
2751 if (task_curr(ctx->task) && !reprogram) {
2756 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2757 } else if (task_ctx) {
2758 raw_spin_lock(&task_ctx->lock);
2761 #ifdef CONFIG_CGROUP_PERF
2762 if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) {
2764 * If the current cgroup doesn't match the event's
2765 * cgroup, we should not try to schedule it.
2767 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2768 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2769 event->cgrp->css.cgroup);
2774 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2775 add_event_to_ctx(event, ctx);
2776 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2778 add_event_to_ctx(event, ctx);
2782 perf_ctx_unlock(cpuctx, task_ctx);
2787 static bool exclusive_event_installable(struct perf_event *event,
2788 struct perf_event_context *ctx);
2791 * Attach a performance event to a context.
2793 * Very similar to event_function_call, see comment there.
2796 perf_install_in_context(struct perf_event_context *ctx,
2797 struct perf_event *event,
2800 struct task_struct *task = READ_ONCE(ctx->task);
2802 lockdep_assert_held(&ctx->mutex);
2804 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2806 if (event->cpu != -1)
2810 * Ensures that if we can observe event->ctx, both the event and ctx
2811 * will be 'complete'. See perf_iterate_sb_cpu().
2813 smp_store_release(&event->ctx, ctx);
2816 * perf_event_attr::disabled events will not run and can be initialized
2817 * without IPI. Except when this is the first event for the context, in
2818 * that case we need the magic of the IPI to set ctx->is_active.
2820 * The IOC_ENABLE that is sure to follow the creation of a disabled
2821 * event will issue the IPI and reprogram the hardware.
2823 if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF && ctx->nr_events) {
2824 raw_spin_lock_irq(&ctx->lock);
2825 if (ctx->task == TASK_TOMBSTONE) {
2826 raw_spin_unlock_irq(&ctx->lock);
2829 add_event_to_ctx(event, ctx);
2830 raw_spin_unlock_irq(&ctx->lock);
2835 cpu_function_call(cpu, __perf_install_in_context, event);
2840 * Should not happen, we validate the ctx is still alive before calling.
2842 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2846 * Installing events is tricky because we cannot rely on ctx->is_active
2847 * to be set in case this is the nr_events 0 -> 1 transition.
2849 * Instead we use task_curr(), which tells us if the task is running.
2850 * However, since we use task_curr() outside of rq::lock, we can race
2851 * against the actual state. This means the result can be wrong.
2853 * If we get a false positive, we retry, this is harmless.
2855 * If we get a false negative, things are complicated. If we are after
2856 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2857 * value must be correct. If we're before, it doesn't matter since
2858 * perf_event_context_sched_in() will program the counter.
2860 * However, this hinges on the remote context switch having observed
2861 * our task->perf_event_ctxp[] store, such that it will in fact take
2862 * ctx::lock in perf_event_context_sched_in().
2864 * We do this by task_function_call(), if the IPI fails to hit the task
2865 * we know any future context switch of task must see the
2866 * perf_event_ctpx[] store.
2870 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2871 * task_cpu() load, such that if the IPI then does not find the task
2872 * running, a future context switch of that task must observe the
2877 if (!task_function_call(task, __perf_install_in_context, event))
2880 raw_spin_lock_irq(&ctx->lock);
2882 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2884 * Cannot happen because we already checked above (which also
2885 * cannot happen), and we hold ctx->mutex, which serializes us
2886 * against perf_event_exit_task_context().
2888 raw_spin_unlock_irq(&ctx->lock);
2892 * If the task is not running, ctx->lock will avoid it becoming so,
2893 * thus we can safely install the event.
2895 if (task_curr(task)) {
2896 raw_spin_unlock_irq(&ctx->lock);
2899 add_event_to_ctx(event, ctx);
2900 raw_spin_unlock_irq(&ctx->lock);
2904 * Cross CPU call to enable a performance event
2906 static void __perf_event_enable(struct perf_event *event,
2907 struct perf_cpu_context *cpuctx,
2908 struct perf_event_context *ctx,
2911 struct perf_event *leader = event->group_leader;
2912 struct perf_event_context *task_ctx;
2914 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2915 event->state <= PERF_EVENT_STATE_ERROR)
2919 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2921 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2922 perf_cgroup_event_enable(event, ctx);
2924 if (!ctx->is_active)
2927 if (!event_filter_match(event)) {
2928 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2933 * If the event is in a group and isn't the group leader,
2934 * then don't put it on unless the group is on.
2936 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2937 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2941 task_ctx = cpuctx->task_ctx;
2943 WARN_ON_ONCE(task_ctx != ctx);
2945 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2951 * If event->ctx is a cloned context, callers must make sure that
2952 * every task struct that event->ctx->task could possibly point to
2953 * remains valid. This condition is satisfied when called through
2954 * perf_event_for_each_child or perf_event_for_each as described
2955 * for perf_event_disable.
2957 static void _perf_event_enable(struct perf_event *event)
2959 struct perf_event_context *ctx = event->ctx;
2961 raw_spin_lock_irq(&ctx->lock);
2962 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2963 event->state < PERF_EVENT_STATE_ERROR) {
2964 raw_spin_unlock_irq(&ctx->lock);
2969 * If the event is in error state, clear that first.
2971 * That way, if we see the event in error state below, we know that it
2972 * has gone back into error state, as distinct from the task having
2973 * been scheduled away before the cross-call arrived.
2975 if (event->state == PERF_EVENT_STATE_ERROR)
2976 event->state = PERF_EVENT_STATE_OFF;
2977 raw_spin_unlock_irq(&ctx->lock);
2979 event_function_call(event, __perf_event_enable, NULL);
2983 * See perf_event_disable();
2985 void perf_event_enable(struct perf_event *event)
2987 struct perf_event_context *ctx;
2989 ctx = perf_event_ctx_lock(event);
2990 _perf_event_enable(event);
2991 perf_event_ctx_unlock(event, ctx);
2993 EXPORT_SYMBOL_GPL(perf_event_enable);
2995 struct stop_event_data {
2996 struct perf_event *event;
2997 unsigned int restart;
3000 static int __perf_event_stop(void *info)
3002 struct stop_event_data *sd = info;
3003 struct perf_event *event = sd->event;
3005 /* if it's already INACTIVE, do nothing */
3006 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3009 /* matches smp_wmb() in event_sched_in() */
3013 * There is a window with interrupts enabled before we get here,
3014 * so we need to check again lest we try to stop another CPU's event.
3016 if (READ_ONCE(event->oncpu) != smp_processor_id())
3019 event->pmu->stop(event, PERF_EF_UPDATE);
3022 * May race with the actual stop (through perf_pmu_output_stop()),
3023 * but it is only used for events with AUX ring buffer, and such
3024 * events will refuse to restart because of rb::aux_mmap_count==0,
3025 * see comments in perf_aux_output_begin().
3027 * Since this is happening on an event-local CPU, no trace is lost
3031 event->pmu->start(event, 0);
3036 static int perf_event_stop(struct perf_event *event, int restart)
3038 struct stop_event_data sd = {
3045 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3048 /* matches smp_wmb() in event_sched_in() */
3052 * We only want to restart ACTIVE events, so if the event goes
3053 * inactive here (event->oncpu==-1), there's nothing more to do;
3054 * fall through with ret==-ENXIO.
3056 ret = cpu_function_call(READ_ONCE(event->oncpu),
3057 __perf_event_stop, &sd);
3058 } while (ret == -EAGAIN);
3064 * In order to contain the amount of racy and tricky in the address filter
3065 * configuration management, it is a two part process:
3067 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
3068 * we update the addresses of corresponding vmas in
3069 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
3070 * (p2) when an event is scheduled in (pmu::add), it calls
3071 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
3072 * if the generation has changed since the previous call.
3074 * If (p1) happens while the event is active, we restart it to force (p2).
3076 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
3077 * pre-existing mappings, called once when new filters arrive via SET_FILTER
3079 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
3080 * registered mapping, called for every new mmap(), with mm::mmap_sem down
3082 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
3085 void perf_event_addr_filters_sync(struct perf_event *event)
3087 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
3089 if (!has_addr_filter(event))
3092 raw_spin_lock(&ifh->lock);
3093 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
3094 event->pmu->addr_filters_sync(event);
3095 event->hw.addr_filters_gen = event->addr_filters_gen;
3097 raw_spin_unlock(&ifh->lock);
3099 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
3101 static int _perf_event_refresh(struct perf_event *event, int refresh)
3104 * not supported on inherited events
3106 if (event->attr.inherit || !is_sampling_event(event))
3109 atomic_add(refresh, &event->event_limit);
3110 _perf_event_enable(event);
3116 * See perf_event_disable()
3118 int perf_event_refresh(struct perf_event *event, int refresh)
3120 struct perf_event_context *ctx;
3123 ctx = perf_event_ctx_lock(event);
3124 ret = _perf_event_refresh(event, refresh);
3125 perf_event_ctx_unlock(event, ctx);
3129 EXPORT_SYMBOL_GPL(perf_event_refresh);
3131 static int perf_event_modify_breakpoint(struct perf_event *bp,
3132 struct perf_event_attr *attr)
3136 _perf_event_disable(bp);
3138 err = modify_user_hw_breakpoint_check(bp, attr, true);
3140 if (!bp->attr.disabled)
3141 _perf_event_enable(bp);
3146 static int perf_event_modify_attr(struct perf_event *event,
3147 struct perf_event_attr *attr)
3149 if (event->attr.type != attr->type)
3152 switch (event->attr.type) {
3153 case PERF_TYPE_BREAKPOINT:
3154 return perf_event_modify_breakpoint(event, attr);
3156 /* Place holder for future additions. */
3161 static void ctx_sched_out(struct perf_event_context *ctx,
3162 struct perf_cpu_context *cpuctx,
3163 enum event_type_t event_type)
3165 struct perf_event *event, *tmp;
3166 int is_active = ctx->is_active;
3168 lockdep_assert_held(&ctx->lock);
3170 if (likely(!ctx->nr_events)) {
3172 * See __perf_remove_from_context().
3174 WARN_ON_ONCE(ctx->is_active);
3176 WARN_ON_ONCE(cpuctx->task_ctx);
3180 ctx->is_active &= ~event_type;
3181 if (!(ctx->is_active & EVENT_ALL))
3185 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3186 if (!ctx->is_active)
3187 cpuctx->task_ctx = NULL;
3191 * Always update time if it was set; not only when it changes.
3192 * Otherwise we can 'forget' to update time for any but the last
3193 * context we sched out. For example:
3195 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3196 * ctx_sched_out(.event_type = EVENT_PINNED)
3198 * would only update time for the pinned events.
3200 if (is_active & EVENT_TIME) {
3201 /* update (and stop) ctx time */
3202 update_context_time(ctx);
3203 update_cgrp_time_from_cpuctx(cpuctx);
3206 is_active ^= ctx->is_active; /* changed bits */
3208 if (!ctx->nr_active || !(is_active & EVENT_ALL))
3211 perf_pmu_disable(ctx->pmu);
3212 if (is_active & EVENT_PINNED) {
3213 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
3214 group_sched_out(event, cpuctx, ctx);
3217 if (is_active & EVENT_FLEXIBLE) {
3218 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
3219 group_sched_out(event, cpuctx, ctx);
3222 * Since we cleared EVENT_FLEXIBLE, also clear
3223 * rotate_necessary, is will be reset by
3224 * ctx_flexible_sched_in() when needed.
3226 ctx->rotate_necessary = 0;
3228 perf_pmu_enable(ctx->pmu);
3232 * Test whether two contexts are equivalent, i.e. whether they have both been
3233 * cloned from the same version of the same context.
3235 * Equivalence is measured using a generation number in the context that is
3236 * incremented on each modification to it; see unclone_ctx(), list_add_event()
3237 * and list_del_event().
3239 static int context_equiv(struct perf_event_context *ctx1,
3240 struct perf_event_context *ctx2)
3242 lockdep_assert_held(&ctx1->lock);
3243 lockdep_assert_held(&ctx2->lock);
3245 /* Pinning disables the swap optimization */
3246 if (ctx1->pin_count || ctx2->pin_count)
3249 /* If ctx1 is the parent of ctx2 */
3250 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3253 /* If ctx2 is the parent of ctx1 */
3254 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3258 * If ctx1 and ctx2 have the same parent; we flatten the parent
3259 * hierarchy, see perf_event_init_context().
3261 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3262 ctx1->parent_gen == ctx2->parent_gen)
3269 static void __perf_event_sync_stat(struct perf_event *event,
3270 struct perf_event *next_event)
3274 if (!event->attr.inherit_stat)
3278 * Update the event value, we cannot use perf_event_read()
3279 * because we're in the middle of a context switch and have IRQs
3280 * disabled, which upsets smp_call_function_single(), however
3281 * we know the event must be on the current CPU, therefore we
3282 * don't need to use it.
3284 if (event->state == PERF_EVENT_STATE_ACTIVE)
3285 event->pmu->read(event);
3287 perf_event_update_time(event);
3290 * In order to keep per-task stats reliable we need to flip the event
3291 * values when we flip the contexts.
3293 value = local64_read(&next_event->count);
3294 value = local64_xchg(&event->count, value);
3295 local64_set(&next_event->count, value);
3297 swap(event->total_time_enabled, next_event->total_time_enabled);
3298 swap(event->total_time_running, next_event->total_time_running);
3301 * Since we swizzled the values, update the user visible data too.
3303 perf_event_update_userpage(event);
3304 perf_event_update_userpage(next_event);
3307 static void perf_event_sync_stat(struct perf_event_context *ctx,
3308 struct perf_event_context *next_ctx)
3310 struct perf_event *event, *next_event;
3315 update_context_time(ctx);
3317 event = list_first_entry(&ctx->event_list,
3318 struct perf_event, event_entry);
3320 next_event = list_first_entry(&next_ctx->event_list,
3321 struct perf_event, event_entry);
3323 while (&event->event_entry != &ctx->event_list &&
3324 &next_event->event_entry != &next_ctx->event_list) {
3326 __perf_event_sync_stat(event, next_event);
3328 event = list_next_entry(event, event_entry);
3329 next_event = list_next_entry(next_event, event_entry);
3333 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3334 struct task_struct *next)
3336 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3337 struct perf_event_context *next_ctx;
3338 struct perf_event_context *parent, *next_parent;
3339 struct perf_cpu_context *cpuctx;
3345 cpuctx = __get_cpu_context(ctx);
3346 if (!cpuctx->task_ctx)
3350 next_ctx = next->perf_event_ctxp[ctxn];
3354 parent = rcu_dereference(ctx->parent_ctx);
3355 next_parent = rcu_dereference(next_ctx->parent_ctx);
3357 /* If neither context have a parent context; they cannot be clones. */
3358 if (!parent && !next_parent)
3361 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3363 * Looks like the two contexts are clones, so we might be
3364 * able to optimize the context switch. We lock both
3365 * contexts and check that they are clones under the
3366 * lock (including re-checking that neither has been
3367 * uncloned in the meantime). It doesn't matter which
3368 * order we take the locks because no other cpu could
3369 * be trying to lock both of these tasks.
3371 raw_spin_lock(&ctx->lock);
3372 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3373 if (context_equiv(ctx, next_ctx)) {
3374 struct pmu *pmu = ctx->pmu;
3376 WRITE_ONCE(ctx->task, next);
3377 WRITE_ONCE(next_ctx->task, task);
3380 * PMU specific parts of task perf context can require
3381 * additional synchronization. As an example of such
3382 * synchronization see implementation details of Intel
3383 * LBR call stack data profiling;
3385 if (pmu->swap_task_ctx)
3386 pmu->swap_task_ctx(ctx, next_ctx);
3388 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3391 * RCU_INIT_POINTER here is safe because we've not
3392 * modified the ctx and the above modification of
3393 * ctx->task and ctx->task_ctx_data are immaterial
3394 * since those values are always verified under
3395 * ctx->lock which we're now holding.
3397 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3398 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3402 perf_event_sync_stat(ctx, next_ctx);
3404 raw_spin_unlock(&next_ctx->lock);
3405 raw_spin_unlock(&ctx->lock);
3411 raw_spin_lock(&ctx->lock);
3412 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3413 raw_spin_unlock(&ctx->lock);
3417 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3419 void perf_sched_cb_dec(struct pmu *pmu)
3421 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3423 this_cpu_dec(perf_sched_cb_usages);
3425 if (!--cpuctx->sched_cb_usage)
3426 list_del(&cpuctx->sched_cb_entry);
3430 void perf_sched_cb_inc(struct pmu *pmu)
3432 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3434 if (!cpuctx->sched_cb_usage++)
3435 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3437 this_cpu_inc(perf_sched_cb_usages);
3441 * This function provides the context switch callback to the lower code
3442 * layer. It is invoked ONLY when the context switch callback is enabled.
3444 * This callback is relevant even to per-cpu events; for example multi event
3445 * PEBS requires this to provide PID/TID information. This requires we flush
3446 * all queued PEBS records before we context switch to a new task.
3448 static void perf_pmu_sched_task(struct task_struct *prev,
3449 struct task_struct *next,
3452 struct perf_cpu_context *cpuctx;
3458 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3459 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3461 if (WARN_ON_ONCE(!pmu->sched_task))
3464 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3465 perf_pmu_disable(pmu);
3467 pmu->sched_task(cpuctx->task_ctx, sched_in);
3469 perf_pmu_enable(pmu);
3470 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3474 static void perf_event_switch(struct task_struct *task,
3475 struct task_struct *next_prev, bool sched_in);
3477 #define for_each_task_context_nr(ctxn) \
3478 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3481 * Called from scheduler to remove the events of the current task,
3482 * with interrupts disabled.
3484 * We stop each event and update the event value in event->count.
3486 * This does not protect us against NMI, but disable()
3487 * sets the disabled bit in the control field of event _before_
3488 * accessing the event control register. If a NMI hits, then it will
3489 * not restart the event.
3491 void __perf_event_task_sched_out(struct task_struct *task,
3492 struct task_struct *next)
3496 if (__this_cpu_read(perf_sched_cb_usages))
3497 perf_pmu_sched_task(task, next, false);
3499 if (atomic_read(&nr_switch_events))
3500 perf_event_switch(task, next, false);
3502 for_each_task_context_nr(ctxn)
3503 perf_event_context_sched_out(task, ctxn, next);
3506 * if cgroup events exist on this CPU, then we need
3507 * to check if we have to switch out PMU state.
3508 * cgroup event are system-wide mode only
3510 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3511 perf_cgroup_sched_out(task, next);
3515 * Called with IRQs disabled
3517 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3518 enum event_type_t event_type)
3520 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3523 static bool perf_less_group_idx(const void *l, const void *r)
3525 const struct perf_event *le = *(const struct perf_event **)l;
3526 const struct perf_event *re = *(const struct perf_event **)r;
3528 return le->group_index < re->group_index;
3531 static void swap_ptr(void *l, void *r)
3533 void **lp = l, **rp = r;
3538 static const struct min_heap_callbacks perf_min_heap = {
3539 .elem_size = sizeof(struct perf_event *),
3540 .less = perf_less_group_idx,
3544 static void __heap_add(struct min_heap *heap, struct perf_event *event)
3546 struct perf_event **itrs = heap->data;
3549 itrs[heap->nr] = event;
3554 static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx,
3555 struct perf_event_groups *groups, int cpu,
3556 int (*func)(struct perf_event *, void *),
3559 #ifdef CONFIG_CGROUP_PERF
3560 struct cgroup_subsys_state *css = NULL;
3562 /* Space for per CPU and/or any CPU event iterators. */
3563 struct perf_event *itrs[2];
3564 struct min_heap event_heap;
3565 struct perf_event **evt;
3569 event_heap = (struct min_heap){
3570 .data = cpuctx->heap,
3572 .size = cpuctx->heap_size,
3575 lockdep_assert_held(&cpuctx->ctx.lock);
3577 #ifdef CONFIG_CGROUP_PERF
3579 css = &cpuctx->cgrp->css;
3582 event_heap = (struct min_heap){
3585 .size = ARRAY_SIZE(itrs),
3587 /* Events not within a CPU context may be on any CPU. */
3588 __heap_add(&event_heap, perf_event_groups_first(groups, -1, NULL));
3590 evt = event_heap.data;
3592 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, NULL));
3594 #ifdef CONFIG_CGROUP_PERF
3595 for (; css; css = css->parent)
3596 __heap_add(&event_heap, perf_event_groups_first(groups, cpu, css->cgroup));
3599 min_heapify_all(&event_heap, &perf_min_heap);
3601 while (event_heap.nr) {
3602 ret = func(*evt, data);
3606 *evt = perf_event_groups_next(*evt);
3608 min_heapify(&event_heap, 0, &perf_min_heap);
3610 min_heap_pop(&event_heap, &perf_min_heap);
3616 static int merge_sched_in(struct perf_event *event, void *data)
3618 struct perf_event_context *ctx = event->ctx;
3619 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3620 int *can_add_hw = data;
3622 if (event->state <= PERF_EVENT_STATE_OFF)
3625 if (!event_filter_match(event))
3628 if (group_can_go_on(event, cpuctx, *can_add_hw)) {
3629 if (!group_sched_in(event, cpuctx, ctx))
3630 list_add_tail(&event->active_list, get_event_list(event));
3633 if (event->state == PERF_EVENT_STATE_INACTIVE) {
3634 if (event->attr.pinned) {
3635 perf_cgroup_event_disable(event, ctx);
3636 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3640 ctx->rotate_necessary = 1;
3647 ctx_pinned_sched_in(struct perf_event_context *ctx,
3648 struct perf_cpu_context *cpuctx)
3652 if (ctx != &cpuctx->ctx)
3655 visit_groups_merge(cpuctx, &ctx->pinned_groups,
3657 merge_sched_in, &can_add_hw);
3661 ctx_flexible_sched_in(struct perf_event_context *ctx,
3662 struct perf_cpu_context *cpuctx)
3666 if (ctx != &cpuctx->ctx)
3669 visit_groups_merge(cpuctx, &ctx->flexible_groups,
3671 merge_sched_in, &can_add_hw);
3675 ctx_sched_in(struct perf_event_context *ctx,
3676 struct perf_cpu_context *cpuctx,
3677 enum event_type_t event_type,
3678 struct task_struct *task)
3680 int is_active = ctx->is_active;
3683 lockdep_assert_held(&ctx->lock);
3685 if (likely(!ctx->nr_events))
3688 ctx->is_active |= (event_type | EVENT_TIME);
3691 cpuctx->task_ctx = ctx;
3693 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3696 is_active ^= ctx->is_active; /* changed bits */
3698 if (is_active & EVENT_TIME) {
3699 /* start ctx time */
3701 ctx->timestamp = now;
3702 perf_cgroup_set_timestamp(task, ctx);
3706 * First go through the list and put on any pinned groups
3707 * in order to give them the best chance of going on.
3709 if (is_active & EVENT_PINNED)
3710 ctx_pinned_sched_in(ctx, cpuctx);
3712 /* Then walk through the lower prio flexible groups */
3713 if (is_active & EVENT_FLEXIBLE)
3714 ctx_flexible_sched_in(ctx, cpuctx);
3717 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3718 enum event_type_t event_type,
3719 struct task_struct *task)
3721 struct perf_event_context *ctx = &cpuctx->ctx;
3723 ctx_sched_in(ctx, cpuctx, event_type, task);
3726 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3727 struct task_struct *task)
3729 struct perf_cpu_context *cpuctx;
3731 cpuctx = __get_cpu_context(ctx);
3732 if (cpuctx->task_ctx == ctx)
3735 perf_ctx_lock(cpuctx, ctx);
3737 * We must check ctx->nr_events while holding ctx->lock, such
3738 * that we serialize against perf_install_in_context().
3740 if (!ctx->nr_events)
3743 perf_pmu_disable(ctx->pmu);
3745 * We want to keep the following priority order:
3746 * cpu pinned (that don't need to move), task pinned,
3747 * cpu flexible, task flexible.
3749 * However, if task's ctx is not carrying any pinned
3750 * events, no need to flip the cpuctx's events around.
3752 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3753 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3754 perf_event_sched_in(cpuctx, ctx, task);
3755 perf_pmu_enable(ctx->pmu);
3758 perf_ctx_unlock(cpuctx, ctx);
3762 * Called from scheduler to add the events of the current task
3763 * with interrupts disabled.
3765 * We restore the event value and then enable it.
3767 * This does not protect us against NMI, but enable()
3768 * sets the enabled bit in the control field of event _before_
3769 * accessing the event control register. If a NMI hits, then it will
3770 * keep the event running.
3772 void __perf_event_task_sched_in(struct task_struct *prev,
3773 struct task_struct *task)
3775 struct perf_event_context *ctx;
3779 * If cgroup events exist on this CPU, then we need to check if we have
3780 * to switch in PMU state; cgroup event are system-wide mode only.
3782 * Since cgroup events are CPU events, we must schedule these in before
3783 * we schedule in the task events.
3785 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3786 perf_cgroup_sched_in(prev, task);
3788 for_each_task_context_nr(ctxn) {
3789 ctx = task->perf_event_ctxp[ctxn];
3793 perf_event_context_sched_in(ctx, task);
3796 if (atomic_read(&nr_switch_events))
3797 perf_event_switch(task, prev, true);
3799 if (__this_cpu_read(perf_sched_cb_usages))
3800 perf_pmu_sched_task(prev, task, true);
3803 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3805 u64 frequency = event->attr.sample_freq;
3806 u64 sec = NSEC_PER_SEC;
3807 u64 divisor, dividend;
3809 int count_fls, nsec_fls, frequency_fls, sec_fls;
3811 count_fls = fls64(count);
3812 nsec_fls = fls64(nsec);
3813 frequency_fls = fls64(frequency);
3817 * We got @count in @nsec, with a target of sample_freq HZ
3818 * the target period becomes:
3821 * period = -------------------
3822 * @nsec * sample_freq
3827 * Reduce accuracy by one bit such that @a and @b converge
3828 * to a similar magnitude.
3830 #define REDUCE_FLS(a, b) \
3832 if (a##_fls > b##_fls) { \
3842 * Reduce accuracy until either term fits in a u64, then proceed with
3843 * the other, so that finally we can do a u64/u64 division.
3845 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3846 REDUCE_FLS(nsec, frequency);
3847 REDUCE_FLS(sec, count);
3850 if (count_fls + sec_fls > 64) {
3851 divisor = nsec * frequency;
3853 while (count_fls + sec_fls > 64) {
3854 REDUCE_FLS(count, sec);
3858 dividend = count * sec;
3860 dividend = count * sec;
3862 while (nsec_fls + frequency_fls > 64) {
3863 REDUCE_FLS(nsec, frequency);
3867 divisor = nsec * frequency;
3873 return div64_u64(dividend, divisor);
3876 static DEFINE_PER_CPU(int, perf_throttled_count);
3877 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3879 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3881 struct hw_perf_event *hwc = &event->hw;
3882 s64 period, sample_period;
3885 period = perf_calculate_period(event, nsec, count);
3887 delta = (s64)(period - hwc->sample_period);
3888 delta = (delta + 7) / 8; /* low pass filter */
3890 sample_period = hwc->sample_period + delta;
3895 hwc->sample_period = sample_period;
3897 if (local64_read(&hwc->period_left) > 8*sample_period) {
3899 event->pmu->stop(event, PERF_EF_UPDATE);
3901 local64_set(&hwc->period_left, 0);
3904 event->pmu->start(event, PERF_EF_RELOAD);
3909 * combine freq adjustment with unthrottling to avoid two passes over the
3910 * events. At the same time, make sure, having freq events does not change
3911 * the rate of unthrottling as that would introduce bias.
3913 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3916 struct perf_event *event;
3917 struct hw_perf_event *hwc;
3918 u64 now, period = TICK_NSEC;
3922 * only need to iterate over all events iff:
3923 * - context have events in frequency mode (needs freq adjust)
3924 * - there are events to unthrottle on this cpu
3926 if (!(ctx->nr_freq || needs_unthr))
3929 raw_spin_lock(&ctx->lock);
3930 perf_pmu_disable(ctx->pmu);
3932 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3933 if (event->state != PERF_EVENT_STATE_ACTIVE)
3936 if (!event_filter_match(event))
3939 perf_pmu_disable(event->pmu);
3943 if (hwc->interrupts == MAX_INTERRUPTS) {
3944 hwc->interrupts = 0;
3945 perf_log_throttle(event, 1);
3946 event->pmu->start(event, 0);
3949 if (!event->attr.freq || !event->attr.sample_freq)
3953 * stop the event and update event->count
3955 event->pmu->stop(event, PERF_EF_UPDATE);
3957 now = local64_read(&event->count);
3958 delta = now - hwc->freq_count_stamp;
3959 hwc->freq_count_stamp = now;
3963 * reload only if value has changed
3964 * we have stopped the event so tell that
3965 * to perf_adjust_period() to avoid stopping it
3969 perf_adjust_period(event, period, delta, false);
3971 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3973 perf_pmu_enable(event->pmu);
3976 perf_pmu_enable(ctx->pmu);
3977 raw_spin_unlock(&ctx->lock);
3981 * Move @event to the tail of the @ctx's elegible events.
3983 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
3986 * Rotate the first entry last of non-pinned groups. Rotation might be
3987 * disabled by the inheritance code.
3989 if (ctx->rotate_disable)
3992 perf_event_groups_delete(&ctx->flexible_groups, event);
3993 perf_event_groups_insert(&ctx->flexible_groups, event);
3996 /* pick an event from the flexible_groups to rotate */
3997 static inline struct perf_event *
3998 ctx_event_to_rotate(struct perf_event_context *ctx)
4000 struct perf_event *event;
4002 /* pick the first active flexible event */
4003 event = list_first_entry_or_null(&ctx->flexible_active,
4004 struct perf_event, active_list);
4006 /* if no active flexible event, pick the first event */
4008 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
4009 typeof(*event), group_node);
4013 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
4014 * finds there are unschedulable events, it will set it again.
4016 ctx->rotate_necessary = 0;
4021 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
4023 struct perf_event *cpu_event = NULL, *task_event = NULL;
4024 struct perf_event_context *task_ctx = NULL;
4025 int cpu_rotate, task_rotate;
4028 * Since we run this from IRQ context, nobody can install new
4029 * events, thus the event count values are stable.
4032 cpu_rotate = cpuctx->ctx.rotate_necessary;
4033 task_ctx = cpuctx->task_ctx;
4034 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
4036 if (!(cpu_rotate || task_rotate))
4039 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
4040 perf_pmu_disable(cpuctx->ctx.pmu);
4043 task_event = ctx_event_to_rotate(task_ctx);
4045 cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
4048 * As per the order given at ctx_resched() first 'pop' task flexible
4049 * and then, if needed CPU flexible.
4051 if (task_event || (task_ctx && cpu_event))
4052 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
4054 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
4057 rotate_ctx(task_ctx, task_event);
4059 rotate_ctx(&cpuctx->ctx, cpu_event);
4061 perf_event_sched_in(cpuctx, task_ctx, current);
4063 perf_pmu_enable(cpuctx->ctx.pmu);
4064 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
4069 void perf_event_task_tick(void)
4071 struct list_head *head = this_cpu_ptr(&active_ctx_list);
4072 struct perf_event_context *ctx, *tmp;
4075 lockdep_assert_irqs_disabled();
4077 __this_cpu_inc(perf_throttled_seq);
4078 throttled = __this_cpu_xchg(perf_throttled_count, 0);
4079 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
4081 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
4082 perf_adjust_freq_unthr_context(ctx, throttled);
4085 static int event_enable_on_exec(struct perf_event *event,
4086 struct perf_event_context *ctx)
4088 if (!event->attr.enable_on_exec)
4091 event->attr.enable_on_exec = 0;
4092 if (event->state >= PERF_EVENT_STATE_INACTIVE)
4095 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
4101 * Enable all of a task's events that have been marked enable-on-exec.
4102 * This expects task == current.
4104 static void perf_event_enable_on_exec(int ctxn)
4106 struct perf_event_context *ctx, *clone_ctx = NULL;
4107 enum event_type_t event_type = 0;
4108 struct perf_cpu_context *cpuctx;
4109 struct perf_event *event;
4110 unsigned long flags;
4113 local_irq_save(flags);
4114 ctx = current->perf_event_ctxp[ctxn];
4115 if (!ctx || !ctx->nr_events)
4118 cpuctx = __get_cpu_context(ctx);
4119 perf_ctx_lock(cpuctx, ctx);
4120 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
4121 list_for_each_entry(event, &ctx->event_list, event_entry) {
4122 enabled |= event_enable_on_exec(event, ctx);
4123 event_type |= get_event_type(event);
4127 * Unclone and reschedule this context if we enabled any event.
4130 clone_ctx = unclone_ctx(ctx);
4131 ctx_resched(cpuctx, ctx, event_type);
4133 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
4135 perf_ctx_unlock(cpuctx, ctx);
4138 local_irq_restore(flags);
4144 struct perf_read_data {
4145 struct perf_event *event;
4150 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
4152 u16 local_pkg, event_pkg;
4154 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
4155 int local_cpu = smp_processor_id();
4157 event_pkg = topology_physical_package_id(event_cpu);
4158 local_pkg = topology_physical_package_id(local_cpu);
4160 if (event_pkg == local_pkg)
4168 * Cross CPU call to read the hardware event
4170 static void __perf_event_read(void *info)
4172 struct perf_read_data *data = info;
4173 struct perf_event *sub, *event = data->event;
4174 struct perf_event_context *ctx = event->ctx;
4175 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
4176 struct pmu *pmu = event->pmu;
4179 * If this is a task context, we need to check whether it is
4180 * the current task context of this cpu. If not it has been
4181 * scheduled out before the smp call arrived. In that case
4182 * event->count would have been updated to a recent sample
4183 * when the event was scheduled out.
4185 if (ctx->task && cpuctx->task_ctx != ctx)
4188 raw_spin_lock(&ctx->lock);
4189 if (ctx->is_active & EVENT_TIME) {
4190 update_context_time(ctx);
4191 update_cgrp_time_from_event(event);
4194 perf_event_update_time(event);
4196 perf_event_update_sibling_time(event);
4198 if (event->state != PERF_EVENT_STATE_ACTIVE)
4207 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
4211 for_each_sibling_event(sub, event) {
4212 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
4214 * Use sibling's PMU rather than @event's since
4215 * sibling could be on different (eg: software) PMU.
4217 sub->pmu->read(sub);
4221 data->ret = pmu->commit_txn(pmu);
4224 raw_spin_unlock(&ctx->lock);
4227 static inline u64 perf_event_count(struct perf_event *event)
4229 return local64_read(&event->count) + atomic64_read(&event->child_count);
4233 * NMI-safe method to read a local event, that is an event that
4235 * - either for the current task, or for this CPU
4236 * - does not have inherit set, for inherited task events
4237 * will not be local and we cannot read them atomically
4238 * - must not have a pmu::count method
4240 int perf_event_read_local(struct perf_event *event, u64 *value,
4241 u64 *enabled, u64 *running)
4243 unsigned long flags;
4247 * Disabling interrupts avoids all counter scheduling (context
4248 * switches, timer based rotation and IPIs).
4250 local_irq_save(flags);
4253 * It must not be an event with inherit set, we cannot read
4254 * all child counters from atomic context.
4256 if (event->attr.inherit) {
4261 /* If this is a per-task event, it must be for current */
4262 if ((event->attach_state & PERF_ATTACH_TASK) &&
4263 event->hw.target != current) {
4268 /* If this is a per-CPU event, it must be for this CPU */
4269 if (!(event->attach_state & PERF_ATTACH_TASK) &&
4270 event->cpu != smp_processor_id()) {
4275 /* If this is a pinned event it must be running on this CPU */
4276 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4282 * If the event is currently on this CPU, its either a per-task event,
4283 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4286 if (event->oncpu == smp_processor_id())
4287 event->pmu->read(event);
4289 *value = local64_read(&event->count);
4290 if (enabled || running) {
4291 u64 now = event->shadow_ctx_time + perf_clock();
4292 u64 __enabled, __running;
4294 __perf_update_times(event, now, &__enabled, &__running);
4296 *enabled = __enabled;
4298 *running = __running;
4301 local_irq_restore(flags);
4306 static int perf_event_read(struct perf_event *event, bool group)
4308 enum perf_event_state state = READ_ONCE(event->state);
4309 int event_cpu, ret = 0;
4312 * If event is enabled and currently active on a CPU, update the
4313 * value in the event structure:
4316 if (state == PERF_EVENT_STATE_ACTIVE) {
4317 struct perf_read_data data;
4320 * Orders the ->state and ->oncpu loads such that if we see
4321 * ACTIVE we must also see the right ->oncpu.
4323 * Matches the smp_wmb() from event_sched_in().
4327 event_cpu = READ_ONCE(event->oncpu);
4328 if ((unsigned)event_cpu >= nr_cpu_ids)
4331 data = (struct perf_read_data){
4338 event_cpu = __perf_event_read_cpu(event, event_cpu);
4341 * Purposely ignore the smp_call_function_single() return
4344 * If event_cpu isn't a valid CPU it means the event got
4345 * scheduled out and that will have updated the event count.
4347 * Therefore, either way, we'll have an up-to-date event count
4350 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4354 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4355 struct perf_event_context *ctx = event->ctx;
4356 unsigned long flags;
4358 raw_spin_lock_irqsave(&ctx->lock, flags);
4359 state = event->state;
4360 if (state != PERF_EVENT_STATE_INACTIVE) {
4361 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4366 * May read while context is not active (e.g., thread is
4367 * blocked), in that case we cannot update context time
4369 if (ctx->is_active & EVENT_TIME) {
4370 update_context_time(ctx);
4371 update_cgrp_time_from_event(event);
4374 perf_event_update_time(event);
4376 perf_event_update_sibling_time(event);
4377 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4384 * Initialize the perf_event context in a task_struct:
4386 static void __perf_event_init_context(struct perf_event_context *ctx)
4388 raw_spin_lock_init(&ctx->lock);
4389 mutex_init(&ctx->mutex);
4390 INIT_LIST_HEAD(&ctx->active_ctx_list);
4391 perf_event_groups_init(&ctx->pinned_groups);
4392 perf_event_groups_init(&ctx->flexible_groups);
4393 INIT_LIST_HEAD(&ctx->event_list);
4394 INIT_LIST_HEAD(&ctx->pinned_active);
4395 INIT_LIST_HEAD(&ctx->flexible_active);
4396 refcount_set(&ctx->refcount, 1);
4399 static struct perf_event_context *
4400 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4402 struct perf_event_context *ctx;
4404 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4408 __perf_event_init_context(ctx);
4410 ctx->task = get_task_struct(task);
4416 static struct task_struct *
4417 find_lively_task_by_vpid(pid_t vpid)
4419 struct task_struct *task;
4425 task = find_task_by_vpid(vpid);
4427 get_task_struct(task);
4431 return ERR_PTR(-ESRCH);
4437 * Returns a matching context with refcount and pincount.
4439 static struct perf_event_context *
4440 find_get_context(struct pmu *pmu, struct task_struct *task,
4441 struct perf_event *event)
4443 struct perf_event_context *ctx, *clone_ctx = NULL;
4444 struct perf_cpu_context *cpuctx;
4445 void *task_ctx_data = NULL;
4446 unsigned long flags;
4448 int cpu = event->cpu;
4451 /* Must be root to operate on a CPU event: */
4452 err = perf_allow_cpu(&event->attr);
4454 return ERR_PTR(err);
4456 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4465 ctxn = pmu->task_ctx_nr;
4469 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4470 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4471 if (!task_ctx_data) {
4478 ctx = perf_lock_task_context(task, ctxn, &flags);
4480 clone_ctx = unclone_ctx(ctx);
4483 if (task_ctx_data && !ctx->task_ctx_data) {
4484 ctx->task_ctx_data = task_ctx_data;
4485 task_ctx_data = NULL;
4487 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4492 ctx = alloc_perf_context(pmu, task);
4497 if (task_ctx_data) {
4498 ctx->task_ctx_data = task_ctx_data;
4499 task_ctx_data = NULL;
4503 mutex_lock(&task->perf_event_mutex);
4505 * If it has already passed perf_event_exit_task().
4506 * we must see PF_EXITING, it takes this mutex too.
4508 if (task->flags & PF_EXITING)
4510 else if (task->perf_event_ctxp[ctxn])
4515 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4517 mutex_unlock(&task->perf_event_mutex);
4519 if (unlikely(err)) {
4528 kfree(task_ctx_data);
4532 kfree(task_ctx_data);
4533 return ERR_PTR(err);
4536 static void perf_event_free_filter(struct perf_event *event);
4537 static void perf_event_free_bpf_prog(struct perf_event *event);
4539 static void free_event_rcu(struct rcu_head *head)
4541 struct perf_event *event;
4543 event = container_of(head, struct perf_event, rcu_head);
4545 put_pid_ns(event->ns);
4546 perf_event_free_filter(event);
4550 static void ring_buffer_attach(struct perf_event *event,
4551 struct perf_buffer *rb);
4553 static void detach_sb_event(struct perf_event *event)
4555 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4557 raw_spin_lock(&pel->lock);
4558 list_del_rcu(&event->sb_list);
4559 raw_spin_unlock(&pel->lock);
4562 static bool is_sb_event(struct perf_event *event)
4564 struct perf_event_attr *attr = &event->attr;
4569 if (event->attach_state & PERF_ATTACH_TASK)
4572 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4573 attr->comm || attr->comm_exec ||
4574 attr->task || attr->ksymbol ||
4575 attr->context_switch ||
4581 static void unaccount_pmu_sb_event(struct perf_event *event)
4583 if (is_sb_event(event))
4584 detach_sb_event(event);
4587 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4592 if (is_cgroup_event(event))
4593 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4596 #ifdef CONFIG_NO_HZ_FULL
4597 static DEFINE_SPINLOCK(nr_freq_lock);
4600 static void unaccount_freq_event_nohz(void)
4602 #ifdef CONFIG_NO_HZ_FULL
4603 spin_lock(&nr_freq_lock);
4604 if (atomic_dec_and_test(&nr_freq_events))
4605 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4606 spin_unlock(&nr_freq_lock);
4610 static void unaccount_freq_event(void)
4612 if (tick_nohz_full_enabled())
4613 unaccount_freq_event_nohz();
4615 atomic_dec(&nr_freq_events);
4618 static void unaccount_event(struct perf_event *event)
4625 if (event->attach_state & PERF_ATTACH_TASK)
4627 if (event->attr.mmap || event->attr.mmap_data)
4628 atomic_dec(&nr_mmap_events);
4629 if (event->attr.comm)
4630 atomic_dec(&nr_comm_events);
4631 if (event->attr.namespaces)
4632 atomic_dec(&nr_namespaces_events);
4633 if (event->attr.cgroup)
4634 atomic_dec(&nr_cgroup_events);
4635 if (event->attr.task)
4636 atomic_dec(&nr_task_events);
4637 if (event->attr.freq)
4638 unaccount_freq_event();
4639 if (event->attr.context_switch) {
4641 atomic_dec(&nr_switch_events);
4643 if (is_cgroup_event(event))
4645 if (has_branch_stack(event))
4647 if (event->attr.ksymbol)
4648 atomic_dec(&nr_ksymbol_events);
4649 if (event->attr.bpf_event)
4650 atomic_dec(&nr_bpf_events);
4653 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4654 schedule_delayed_work(&perf_sched_work, HZ);
4657 unaccount_event_cpu(event, event->cpu);
4659 unaccount_pmu_sb_event(event);
4662 static void perf_sched_delayed(struct work_struct *work)
4664 mutex_lock(&perf_sched_mutex);
4665 if (atomic_dec_and_test(&perf_sched_count))
4666 static_branch_disable(&perf_sched_events);
4667 mutex_unlock(&perf_sched_mutex);
4671 * The following implement mutual exclusion of events on "exclusive" pmus
4672 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4673 * at a time, so we disallow creating events that might conflict, namely:
4675 * 1) cpu-wide events in the presence of per-task events,
4676 * 2) per-task events in the presence of cpu-wide events,
4677 * 3) two matching events on the same context.
4679 * The former two cases are handled in the allocation path (perf_event_alloc(),
4680 * _free_event()), the latter -- before the first perf_install_in_context().
4682 static int exclusive_event_init(struct perf_event *event)
4684 struct pmu *pmu = event->pmu;
4686 if (!is_exclusive_pmu(pmu))
4690 * Prevent co-existence of per-task and cpu-wide events on the
4691 * same exclusive pmu.
4693 * Negative pmu::exclusive_cnt means there are cpu-wide
4694 * events on this "exclusive" pmu, positive means there are
4697 * Since this is called in perf_event_alloc() path, event::ctx
4698 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4699 * to mean "per-task event", because unlike other attach states it
4700 * never gets cleared.
4702 if (event->attach_state & PERF_ATTACH_TASK) {
4703 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4706 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4713 static void exclusive_event_destroy(struct perf_event *event)
4715 struct pmu *pmu = event->pmu;
4717 if (!is_exclusive_pmu(pmu))
4720 /* see comment in exclusive_event_init() */
4721 if (event->attach_state & PERF_ATTACH_TASK)
4722 atomic_dec(&pmu->exclusive_cnt);
4724 atomic_inc(&pmu->exclusive_cnt);
4727 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4729 if ((e1->pmu == e2->pmu) &&
4730 (e1->cpu == e2->cpu ||
4737 static bool exclusive_event_installable(struct perf_event *event,
4738 struct perf_event_context *ctx)
4740 struct perf_event *iter_event;
4741 struct pmu *pmu = event->pmu;
4743 lockdep_assert_held(&ctx->mutex);
4745 if (!is_exclusive_pmu(pmu))
4748 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4749 if (exclusive_event_match(iter_event, event))
4756 static void perf_addr_filters_splice(struct perf_event *event,
4757 struct list_head *head);
4759 static void _free_event(struct perf_event *event)
4761 irq_work_sync(&event->pending);
4763 unaccount_event(event);
4765 security_perf_event_free(event);
4769 * Can happen when we close an event with re-directed output.
4771 * Since we have a 0 refcount, perf_mmap_close() will skip
4772 * over us; possibly making our ring_buffer_put() the last.
4774 mutex_lock(&event->mmap_mutex);
4775 ring_buffer_attach(event, NULL);
4776 mutex_unlock(&event->mmap_mutex);
4779 if (is_cgroup_event(event))
4780 perf_detach_cgroup(event);
4782 if (!event->parent) {
4783 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4784 put_callchain_buffers();
4787 perf_event_free_bpf_prog(event);
4788 perf_addr_filters_splice(event, NULL);
4789 kfree(event->addr_filter_ranges);
4792 event->destroy(event);
4795 * Must be after ->destroy(), due to uprobe_perf_close() using
4798 if (event->hw.target)
4799 put_task_struct(event->hw.target);
4802 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4803 * all task references must be cleaned up.
4806 put_ctx(event->ctx);
4808 exclusive_event_destroy(event);
4809 module_put(event->pmu->module);
4811 call_rcu(&event->rcu_head, free_event_rcu);
4815 * Used to free events which have a known refcount of 1, such as in error paths
4816 * where the event isn't exposed yet and inherited events.
4818 static void free_event(struct perf_event *event)
4820 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4821 "unexpected event refcount: %ld; ptr=%p\n",
4822 atomic_long_read(&event->refcount), event)) {
4823 /* leak to avoid use-after-free */
4831 * Remove user event from the owner task.
4833 static void perf_remove_from_owner(struct perf_event *event)
4835 struct task_struct *owner;
4839 * Matches the smp_store_release() in perf_event_exit_task(). If we
4840 * observe !owner it means the list deletion is complete and we can
4841 * indeed free this event, otherwise we need to serialize on
4842 * owner->perf_event_mutex.
4844 owner = READ_ONCE(event->owner);
4847 * Since delayed_put_task_struct() also drops the last
4848 * task reference we can safely take a new reference
4849 * while holding the rcu_read_lock().
4851 get_task_struct(owner);
4857 * If we're here through perf_event_exit_task() we're already
4858 * holding ctx->mutex which would be an inversion wrt. the
4859 * normal lock order.
4861 * However we can safely take this lock because its the child
4864 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4867 * We have to re-check the event->owner field, if it is cleared
4868 * we raced with perf_event_exit_task(), acquiring the mutex
4869 * ensured they're done, and we can proceed with freeing the
4873 list_del_init(&event->owner_entry);
4874 smp_store_release(&event->owner, NULL);
4876 mutex_unlock(&owner->perf_event_mutex);
4877 put_task_struct(owner);
4881 static void put_event(struct perf_event *event)
4883 if (!atomic_long_dec_and_test(&event->refcount))
4890 * Kill an event dead; while event:refcount will preserve the event
4891 * object, it will not preserve its functionality. Once the last 'user'
4892 * gives up the object, we'll destroy the thing.
4894 int perf_event_release_kernel(struct perf_event *event)
4896 struct perf_event_context *ctx = event->ctx;
4897 struct perf_event *child, *tmp;
4898 LIST_HEAD(free_list);
4901 * If we got here through err_file: fput(event_file); we will not have
4902 * attached to a context yet.
4905 WARN_ON_ONCE(event->attach_state &
4906 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4910 if (!is_kernel_event(event))
4911 perf_remove_from_owner(event);
4913 ctx = perf_event_ctx_lock(event);
4914 WARN_ON_ONCE(ctx->parent_ctx);
4915 perf_remove_from_context(event, DETACH_GROUP);
4917 raw_spin_lock_irq(&ctx->lock);
4919 * Mark this event as STATE_DEAD, there is no external reference to it
4922 * Anybody acquiring event->child_mutex after the below loop _must_
4923 * also see this, most importantly inherit_event() which will avoid
4924 * placing more children on the list.
4926 * Thus this guarantees that we will in fact observe and kill _ALL_
4929 event->state = PERF_EVENT_STATE_DEAD;
4930 raw_spin_unlock_irq(&ctx->lock);
4932 perf_event_ctx_unlock(event, ctx);
4935 mutex_lock(&event->child_mutex);
4936 list_for_each_entry(child, &event->child_list, child_list) {
4939 * Cannot change, child events are not migrated, see the
4940 * comment with perf_event_ctx_lock_nested().
4942 ctx = READ_ONCE(child->ctx);
4944 * Since child_mutex nests inside ctx::mutex, we must jump
4945 * through hoops. We start by grabbing a reference on the ctx.
4947 * Since the event cannot get freed while we hold the
4948 * child_mutex, the context must also exist and have a !0
4954 * Now that we have a ctx ref, we can drop child_mutex, and
4955 * acquire ctx::mutex without fear of it going away. Then we
4956 * can re-acquire child_mutex.
4958 mutex_unlock(&event->child_mutex);
4959 mutex_lock(&ctx->mutex);
4960 mutex_lock(&event->child_mutex);
4963 * Now that we hold ctx::mutex and child_mutex, revalidate our
4964 * state, if child is still the first entry, it didn't get freed
4965 * and we can continue doing so.
4967 tmp = list_first_entry_or_null(&event->child_list,
4968 struct perf_event, child_list);
4970 perf_remove_from_context(child, DETACH_GROUP);
4971 list_move(&child->child_list, &free_list);
4973 * This matches the refcount bump in inherit_event();
4974 * this can't be the last reference.
4979 mutex_unlock(&event->child_mutex);
4980 mutex_unlock(&ctx->mutex);
4984 mutex_unlock(&event->child_mutex);
4986 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4987 void *var = &child->ctx->refcount;
4989 list_del(&child->child_list);
4993 * Wake any perf_event_free_task() waiting for this event to be
4996 smp_mb(); /* pairs with wait_var_event() */
5001 put_event(event); /* Must be the 'last' reference */
5004 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
5007 * Called when the last reference to the file is gone.
5009 static int perf_release(struct inode *inode, struct file *file)
5011 perf_event_release_kernel(file->private_data);
5015 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5017 struct perf_event *child;
5023 mutex_lock(&event->child_mutex);
5025 (void)perf_event_read(event, false);
5026 total += perf_event_count(event);
5028 *enabled += event->total_time_enabled +
5029 atomic64_read(&event->child_total_time_enabled);
5030 *running += event->total_time_running +
5031 atomic64_read(&event->child_total_time_running);
5033 list_for_each_entry(child, &event->child_list, child_list) {
5034 (void)perf_event_read(child, false);
5035 total += perf_event_count(child);
5036 *enabled += child->total_time_enabled;
5037 *running += child->total_time_running;
5039 mutex_unlock(&event->child_mutex);
5044 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5046 struct perf_event_context *ctx;
5049 ctx = perf_event_ctx_lock(event);
5050 count = __perf_event_read_value(event, enabled, running);
5051 perf_event_ctx_unlock(event, ctx);
5055 EXPORT_SYMBOL_GPL(perf_event_read_value);
5057 static int __perf_read_group_add(struct perf_event *leader,
5058 u64 read_format, u64 *values)
5060 struct perf_event_context *ctx = leader->ctx;
5061 struct perf_event *sub;
5062 unsigned long flags;
5063 int n = 1; /* skip @nr */
5066 ret = perf_event_read(leader, true);
5070 raw_spin_lock_irqsave(&ctx->lock, flags);
5073 * Since we co-schedule groups, {enabled,running} times of siblings
5074 * will be identical to those of the leader, so we only publish one
5077 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5078 values[n++] += leader->total_time_enabled +
5079 atomic64_read(&leader->child_total_time_enabled);
5082 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5083 values[n++] += leader->total_time_running +
5084 atomic64_read(&leader->child_total_time_running);
5088 * Write {count,id} tuples for every sibling.
5090 values[n++] += perf_event_count(leader);
5091 if (read_format & PERF_FORMAT_ID)
5092 values[n++] = primary_event_id(leader);
5094 for_each_sibling_event(sub, leader) {
5095 values[n++] += perf_event_count(sub);
5096 if (read_format & PERF_FORMAT_ID)
5097 values[n++] = primary_event_id(sub);
5100 raw_spin_unlock_irqrestore(&ctx->lock, flags);
5104 static int perf_read_group(struct perf_event *event,
5105 u64 read_format, char __user *buf)
5107 struct perf_event *leader = event->group_leader, *child;
5108 struct perf_event_context *ctx = leader->ctx;
5112 lockdep_assert_held(&ctx->mutex);
5114 values = kzalloc(event->read_size, GFP_KERNEL);
5118 values[0] = 1 + leader->nr_siblings;
5121 * By locking the child_mutex of the leader we effectively
5122 * lock the child list of all siblings.. XXX explain how.
5124 mutex_lock(&leader->child_mutex);
5126 ret = __perf_read_group_add(leader, read_format, values);
5130 list_for_each_entry(child, &leader->child_list, child_list) {
5131 ret = __perf_read_group_add(child, read_format, values);
5136 mutex_unlock(&leader->child_mutex);
5138 ret = event->read_size;
5139 if (copy_to_user(buf, values, event->read_size))
5144 mutex_unlock(&leader->child_mutex);
5150 static int perf_read_one(struct perf_event *event,
5151 u64 read_format, char __user *buf)
5153 u64 enabled, running;
5157 values[n++] = __perf_event_read_value(event, &enabled, &running);
5158 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5159 values[n++] = enabled;
5160 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5161 values[n++] = running;
5162 if (read_format & PERF_FORMAT_ID)
5163 values[n++] = primary_event_id(event);
5165 if (copy_to_user(buf, values, n * sizeof(u64)))
5168 return n * sizeof(u64);
5171 static bool is_event_hup(struct perf_event *event)
5175 if (event->state > PERF_EVENT_STATE_EXIT)
5178 mutex_lock(&event->child_mutex);
5179 no_children = list_empty(&event->child_list);
5180 mutex_unlock(&event->child_mutex);
5185 * Read the performance event - simple non blocking version for now
5188 __perf_read(struct perf_event *event, char __user *buf, size_t count)
5190 u64 read_format = event->attr.read_format;
5194 * Return end-of-file for a read on an event that is in
5195 * error state (i.e. because it was pinned but it couldn't be
5196 * scheduled on to the CPU at some point).
5198 if (event->state == PERF_EVENT_STATE_ERROR)
5201 if (count < event->read_size)
5204 WARN_ON_ONCE(event->ctx->parent_ctx);
5205 if (read_format & PERF_FORMAT_GROUP)
5206 ret = perf_read_group(event, read_format, buf);
5208 ret = perf_read_one(event, read_format, buf);
5214 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
5216 struct perf_event *event = file->private_data;
5217 struct perf_event_context *ctx;
5220 ret = security_perf_event_read(event);
5224 ctx = perf_event_ctx_lock(event);
5225 ret = __perf_read(event, buf, count);
5226 perf_event_ctx_unlock(event, ctx);
5231 static __poll_t perf_poll(struct file *file, poll_table *wait)
5233 struct perf_event *event = file->private_data;
5234 struct perf_buffer *rb;
5235 __poll_t events = EPOLLHUP;
5237 poll_wait(file, &event->waitq, wait);
5239 if (is_event_hup(event))
5243 * Pin the event->rb by taking event->mmap_mutex; otherwise
5244 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5246 mutex_lock(&event->mmap_mutex);
5249 events = atomic_xchg(&rb->poll, 0);
5250 mutex_unlock(&event->mmap_mutex);
5254 static void _perf_event_reset(struct perf_event *event)
5256 (void)perf_event_read(event, false);
5257 local64_set(&event->count, 0);
5258 perf_event_update_userpage(event);
5261 /* Assume it's not an event with inherit set. */
5262 u64 perf_event_pause(struct perf_event *event, bool reset)
5264 struct perf_event_context *ctx;
5267 ctx = perf_event_ctx_lock(event);
5268 WARN_ON_ONCE(event->attr.inherit);
5269 _perf_event_disable(event);
5270 count = local64_read(&event->count);
5272 local64_set(&event->count, 0);
5273 perf_event_ctx_unlock(event, ctx);
5277 EXPORT_SYMBOL_GPL(perf_event_pause);
5280 * Holding the top-level event's child_mutex means that any
5281 * descendant process that has inherited this event will block
5282 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5283 * task existence requirements of perf_event_enable/disable.
5285 static void perf_event_for_each_child(struct perf_event *event,
5286 void (*func)(struct perf_event *))
5288 struct perf_event *child;
5290 WARN_ON_ONCE(event->ctx->parent_ctx);
5292 mutex_lock(&event->child_mutex);
5294 list_for_each_entry(child, &event->child_list, child_list)
5296 mutex_unlock(&event->child_mutex);
5299 static void perf_event_for_each(struct perf_event *event,
5300 void (*func)(struct perf_event *))
5302 struct perf_event_context *ctx = event->ctx;
5303 struct perf_event *sibling;
5305 lockdep_assert_held(&ctx->mutex);
5307 event = event->group_leader;
5309 perf_event_for_each_child(event, func);
5310 for_each_sibling_event(sibling, event)
5311 perf_event_for_each_child(sibling, func);
5314 static void __perf_event_period(struct perf_event *event,
5315 struct perf_cpu_context *cpuctx,
5316 struct perf_event_context *ctx,
5319 u64 value = *((u64 *)info);
5322 if (event->attr.freq) {
5323 event->attr.sample_freq = value;
5325 event->attr.sample_period = value;
5326 event->hw.sample_period = value;
5329 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5331 perf_pmu_disable(ctx->pmu);
5333 * We could be throttled; unthrottle now to avoid the tick
5334 * trying to unthrottle while we already re-started the event.
5336 if (event->hw.interrupts == MAX_INTERRUPTS) {
5337 event->hw.interrupts = 0;
5338 perf_log_throttle(event, 1);
5340 event->pmu->stop(event, PERF_EF_UPDATE);
5343 local64_set(&event->hw.period_left, 0);
5346 event->pmu->start(event, PERF_EF_RELOAD);
5347 perf_pmu_enable(ctx->pmu);
5351 static int perf_event_check_period(struct perf_event *event, u64 value)
5353 return event->pmu->check_period(event, value);
5356 static int _perf_event_period(struct perf_event *event, u64 value)
5358 if (!is_sampling_event(event))
5364 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5367 if (perf_event_check_period(event, value))
5370 if (!event->attr.freq && (value & (1ULL << 63)))
5373 event_function_call(event, __perf_event_period, &value);
5378 int perf_event_period(struct perf_event *event, u64 value)
5380 struct perf_event_context *ctx;
5383 ctx = perf_event_ctx_lock(event);
5384 ret = _perf_event_period(event, value);
5385 perf_event_ctx_unlock(event, ctx);
5389 EXPORT_SYMBOL_GPL(perf_event_period);
5391 static const struct file_operations perf_fops;
5393 static inline int perf_fget_light(int fd, struct fd *p)
5395 struct fd f = fdget(fd);
5399 if (f.file->f_op != &perf_fops) {
5407 static int perf_event_set_output(struct perf_event *event,
5408 struct perf_event *output_event);
5409 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5410 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5411 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5412 struct perf_event_attr *attr);
5414 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5416 void (*func)(struct perf_event *);
5420 case PERF_EVENT_IOC_ENABLE:
5421 func = _perf_event_enable;
5423 case PERF_EVENT_IOC_DISABLE:
5424 func = _perf_event_disable;
5426 case PERF_EVENT_IOC_RESET:
5427 func = _perf_event_reset;
5430 case PERF_EVENT_IOC_REFRESH:
5431 return _perf_event_refresh(event, arg);
5433 case PERF_EVENT_IOC_PERIOD:
5437 if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
5440 return _perf_event_period(event, value);
5442 case PERF_EVENT_IOC_ID:
5444 u64 id = primary_event_id(event);
5446 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5451 case PERF_EVENT_IOC_SET_OUTPUT:
5455 struct perf_event *output_event;
5457 ret = perf_fget_light(arg, &output);
5460 output_event = output.file->private_data;
5461 ret = perf_event_set_output(event, output_event);
5464 ret = perf_event_set_output(event, NULL);
5469 case PERF_EVENT_IOC_SET_FILTER:
5470 return perf_event_set_filter(event, (void __user *)arg);
5472 case PERF_EVENT_IOC_SET_BPF:
5473 return perf_event_set_bpf_prog(event, arg);
5475 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5476 struct perf_buffer *rb;
5479 rb = rcu_dereference(event->rb);
5480 if (!rb || !rb->nr_pages) {
5484 rb_toggle_paused(rb, !!arg);
5489 case PERF_EVENT_IOC_QUERY_BPF:
5490 return perf_event_query_prog_array(event, (void __user *)arg);
5492 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5493 struct perf_event_attr new_attr;
5494 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5500 return perf_event_modify_attr(event, &new_attr);
5506 if (flags & PERF_IOC_FLAG_GROUP)
5507 perf_event_for_each(event, func);
5509 perf_event_for_each_child(event, func);
5514 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5516 struct perf_event *event = file->private_data;
5517 struct perf_event_context *ctx;
5520 /* Treat ioctl like writes as it is likely a mutating operation. */
5521 ret = security_perf_event_write(event);
5525 ctx = perf_event_ctx_lock(event);
5526 ret = _perf_ioctl(event, cmd, arg);
5527 perf_event_ctx_unlock(event, ctx);
5532 #ifdef CONFIG_COMPAT
5533 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5536 switch (_IOC_NR(cmd)) {
5537 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5538 case _IOC_NR(PERF_EVENT_IOC_ID):
5539 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5540 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5541 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5542 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5543 cmd &= ~IOCSIZE_MASK;
5544 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5548 return perf_ioctl(file, cmd, arg);
5551 # define perf_compat_ioctl NULL
5554 int perf_event_task_enable(void)
5556 struct perf_event_context *ctx;
5557 struct perf_event *event;
5559 mutex_lock(¤t->perf_event_mutex);
5560 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5561 ctx = perf_event_ctx_lock(event);
5562 perf_event_for_each_child(event, _perf_event_enable);
5563 perf_event_ctx_unlock(event, ctx);
5565 mutex_unlock(¤t->perf_event_mutex);
5570 int perf_event_task_disable(void)
5572 struct perf_event_context *ctx;
5573 struct perf_event *event;
5575 mutex_lock(¤t->perf_event_mutex);
5576 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5577 ctx = perf_event_ctx_lock(event);
5578 perf_event_for_each_child(event, _perf_event_disable);
5579 perf_event_ctx_unlock(event, ctx);
5581 mutex_unlock(¤t->perf_event_mutex);
5586 static int perf_event_index(struct perf_event *event)
5588 if (event->hw.state & PERF_HES_STOPPED)
5591 if (event->state != PERF_EVENT_STATE_ACTIVE)
5594 return event->pmu->event_idx(event);
5597 static void calc_timer_values(struct perf_event *event,
5604 *now = perf_clock();
5605 ctx_time = event->shadow_ctx_time + *now;
5606 __perf_update_times(event, ctx_time, enabled, running);
5609 static void perf_event_init_userpage(struct perf_event *event)
5611 struct perf_event_mmap_page *userpg;
5612 struct perf_buffer *rb;
5615 rb = rcu_dereference(event->rb);
5619 userpg = rb->user_page;
5621 /* Allow new userspace to detect that bit 0 is deprecated */
5622 userpg->cap_bit0_is_deprecated = 1;
5623 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5624 userpg->data_offset = PAGE_SIZE;
5625 userpg->data_size = perf_data_size(rb);
5631 void __weak arch_perf_update_userpage(
5632 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5637 * Callers need to ensure there can be no nesting of this function, otherwise
5638 * the seqlock logic goes bad. We can not serialize this because the arch
5639 * code calls this from NMI context.
5641 void perf_event_update_userpage(struct perf_event *event)
5643 struct perf_event_mmap_page *userpg;
5644 struct perf_buffer *rb;
5645 u64 enabled, running, now;
5648 rb = rcu_dereference(event->rb);
5653 * compute total_time_enabled, total_time_running
5654 * based on snapshot values taken when the event
5655 * was last scheduled in.
5657 * we cannot simply called update_context_time()
5658 * because of locking issue as we can be called in
5661 calc_timer_values(event, &now, &enabled, &running);
5663 userpg = rb->user_page;
5665 * Disable preemption to guarantee consistent time stamps are stored to
5671 userpg->index = perf_event_index(event);
5672 userpg->offset = perf_event_count(event);
5674 userpg->offset -= local64_read(&event->hw.prev_count);
5676 userpg->time_enabled = enabled +
5677 atomic64_read(&event->child_total_time_enabled);
5679 userpg->time_running = running +
5680 atomic64_read(&event->child_total_time_running);
5682 arch_perf_update_userpage(event, userpg, now);
5690 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5692 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5694 struct perf_event *event = vmf->vma->vm_file->private_data;
5695 struct perf_buffer *rb;
5696 vm_fault_t ret = VM_FAULT_SIGBUS;
5698 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5699 if (vmf->pgoff == 0)
5705 rb = rcu_dereference(event->rb);
5709 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5712 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5716 get_page(vmf->page);
5717 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5718 vmf->page->index = vmf->pgoff;
5727 static void ring_buffer_attach(struct perf_event *event,
5728 struct perf_buffer *rb)
5730 struct perf_buffer *old_rb = NULL;
5731 unsigned long flags;
5735 * Should be impossible, we set this when removing
5736 * event->rb_entry and wait/clear when adding event->rb_entry.
5738 WARN_ON_ONCE(event->rcu_pending);
5741 spin_lock_irqsave(&old_rb->event_lock, flags);
5742 list_del_rcu(&event->rb_entry);
5743 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5745 event->rcu_batches = get_state_synchronize_rcu();
5746 event->rcu_pending = 1;
5750 if (event->rcu_pending) {
5751 cond_synchronize_rcu(event->rcu_batches);
5752 event->rcu_pending = 0;
5755 spin_lock_irqsave(&rb->event_lock, flags);
5756 list_add_rcu(&event->rb_entry, &rb->event_list);
5757 spin_unlock_irqrestore(&rb->event_lock, flags);
5761 * Avoid racing with perf_mmap_close(AUX): stop the event
5762 * before swizzling the event::rb pointer; if it's getting
5763 * unmapped, its aux_mmap_count will be 0 and it won't
5764 * restart. See the comment in __perf_pmu_output_stop().
5766 * Data will inevitably be lost when set_output is done in
5767 * mid-air, but then again, whoever does it like this is
5768 * not in for the data anyway.
5771 perf_event_stop(event, 0);
5773 rcu_assign_pointer(event->rb, rb);
5776 ring_buffer_put(old_rb);
5778 * Since we detached before setting the new rb, so that we
5779 * could attach the new rb, we could have missed a wakeup.
5782 wake_up_all(&event->waitq);
5786 static void ring_buffer_wakeup(struct perf_event *event)
5788 struct perf_buffer *rb;
5791 rb = rcu_dereference(event->rb);
5793 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5794 wake_up_all(&event->waitq);
5799 struct perf_buffer *ring_buffer_get(struct perf_event *event)
5801 struct perf_buffer *rb;
5804 rb = rcu_dereference(event->rb);
5806 if (!refcount_inc_not_zero(&rb->refcount))
5814 void ring_buffer_put(struct perf_buffer *rb)
5816 if (!refcount_dec_and_test(&rb->refcount))
5819 WARN_ON_ONCE(!list_empty(&rb->event_list));
5821 call_rcu(&rb->rcu_head, rb_free_rcu);
5824 static void perf_mmap_open(struct vm_area_struct *vma)
5826 struct perf_event *event = vma->vm_file->private_data;
5828 atomic_inc(&event->mmap_count);
5829 atomic_inc(&event->rb->mmap_count);
5832 atomic_inc(&event->rb->aux_mmap_count);
5834 if (event->pmu->event_mapped)
5835 event->pmu->event_mapped(event, vma->vm_mm);
5838 static void perf_pmu_output_stop(struct perf_event *event);
5841 * A buffer can be mmap()ed multiple times; either directly through the same
5842 * event, or through other events by use of perf_event_set_output().
5844 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5845 * the buffer here, where we still have a VM context. This means we need
5846 * to detach all events redirecting to us.
5848 static void perf_mmap_close(struct vm_area_struct *vma)
5850 struct perf_event *event = vma->vm_file->private_data;
5852 struct perf_buffer *rb = ring_buffer_get(event);
5853 struct user_struct *mmap_user = rb->mmap_user;
5854 int mmap_locked = rb->mmap_locked;
5855 unsigned long size = perf_data_size(rb);
5857 if (event->pmu->event_unmapped)
5858 event->pmu->event_unmapped(event, vma->vm_mm);
5861 * rb->aux_mmap_count will always drop before rb->mmap_count and
5862 * event->mmap_count, so it is ok to use event->mmap_mutex to
5863 * serialize with perf_mmap here.
5865 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5866 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5868 * Stop all AUX events that are writing to this buffer,
5869 * so that we can free its AUX pages and corresponding PMU
5870 * data. Note that after rb::aux_mmap_count dropped to zero,
5871 * they won't start any more (see perf_aux_output_begin()).
5873 perf_pmu_output_stop(event);
5875 /* now it's safe to free the pages */
5876 atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
5877 atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
5879 /* this has to be the last one */
5881 WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
5883 mutex_unlock(&event->mmap_mutex);
5886 atomic_dec(&rb->mmap_count);
5888 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5891 ring_buffer_attach(event, NULL);
5892 mutex_unlock(&event->mmap_mutex);
5894 /* If there's still other mmap()s of this buffer, we're done. */
5895 if (atomic_read(&rb->mmap_count))
5899 * No other mmap()s, detach from all other events that might redirect
5900 * into the now unreachable buffer. Somewhat complicated by the
5901 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5905 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5906 if (!atomic_long_inc_not_zero(&event->refcount)) {
5908 * This event is en-route to free_event() which will
5909 * detach it and remove it from the list.
5915 mutex_lock(&event->mmap_mutex);
5917 * Check we didn't race with perf_event_set_output() which can
5918 * swizzle the rb from under us while we were waiting to
5919 * acquire mmap_mutex.
5921 * If we find a different rb; ignore this event, a next
5922 * iteration will no longer find it on the list. We have to
5923 * still restart the iteration to make sure we're not now
5924 * iterating the wrong list.
5926 if (event->rb == rb)
5927 ring_buffer_attach(event, NULL);
5929 mutex_unlock(&event->mmap_mutex);
5933 * Restart the iteration; either we're on the wrong list or
5934 * destroyed its integrity by doing a deletion.
5941 * It could be there's still a few 0-ref events on the list; they'll
5942 * get cleaned up by free_event() -- they'll also still have their
5943 * ref on the rb and will free it whenever they are done with it.
5945 * Aside from that, this buffer is 'fully' detached and unmapped,
5946 * undo the VM accounting.
5949 atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
5950 &mmap_user->locked_vm);
5951 atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
5952 free_uid(mmap_user);
5955 ring_buffer_put(rb); /* could be last */
5958 static const struct vm_operations_struct perf_mmap_vmops = {
5959 .open = perf_mmap_open,
5960 .close = perf_mmap_close, /* non mergeable */
5961 .fault = perf_mmap_fault,
5962 .page_mkwrite = perf_mmap_fault,
5965 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5967 struct perf_event *event = file->private_data;
5968 unsigned long user_locked, user_lock_limit;
5969 struct user_struct *user = current_user();
5970 struct perf_buffer *rb = NULL;
5971 unsigned long locked, lock_limit;
5972 unsigned long vma_size;
5973 unsigned long nr_pages;
5974 long user_extra = 0, extra = 0;
5975 int ret = 0, flags = 0;
5978 * Don't allow mmap() of inherited per-task counters. This would
5979 * create a performance issue due to all children writing to the
5982 if (event->cpu == -1 && event->attr.inherit)
5985 if (!(vma->vm_flags & VM_SHARED))
5988 ret = security_perf_event_read(event);
5992 vma_size = vma->vm_end - vma->vm_start;
5994 if (vma->vm_pgoff == 0) {
5995 nr_pages = (vma_size / PAGE_SIZE) - 1;
5998 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5999 * mapped, all subsequent mappings should have the same size
6000 * and offset. Must be above the normal perf buffer.
6002 u64 aux_offset, aux_size;
6007 nr_pages = vma_size / PAGE_SIZE;
6009 mutex_lock(&event->mmap_mutex);
6016 aux_offset = READ_ONCE(rb->user_page->aux_offset);
6017 aux_size = READ_ONCE(rb->user_page->aux_size);
6019 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
6022 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
6025 /* already mapped with a different offset */
6026 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
6029 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
6032 /* already mapped with a different size */
6033 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
6036 if (!is_power_of_2(nr_pages))
6039 if (!atomic_inc_not_zero(&rb->mmap_count))
6042 if (rb_has_aux(rb)) {
6043 atomic_inc(&rb->aux_mmap_count);
6048 atomic_set(&rb->aux_mmap_count, 1);
6049 user_extra = nr_pages;
6055 * If we have rb pages ensure they're a power-of-two number, so we
6056 * can do bitmasks instead of modulo.
6058 if (nr_pages != 0 && !is_power_of_2(nr_pages))
6061 if (vma_size != PAGE_SIZE * (1 + nr_pages))
6064 WARN_ON_ONCE(event->ctx->parent_ctx);
6066 mutex_lock(&event->mmap_mutex);
6068 if (event->rb->nr_pages != nr_pages) {
6073 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
6075 * Raced against perf_mmap_close() through
6076 * perf_event_set_output(). Try again, hope for better
6079 mutex_unlock(&event->mmap_mutex);
6086 user_extra = nr_pages + 1;
6089 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
6092 * Increase the limit linearly with more CPUs:
6094 user_lock_limit *= num_online_cpus();
6096 user_locked = atomic_long_read(&user->locked_vm);
6099 * sysctl_perf_event_mlock may have changed, so that
6100 * user->locked_vm > user_lock_limit
6102 if (user_locked > user_lock_limit)
6103 user_locked = user_lock_limit;
6104 user_locked += user_extra;
6106 if (user_locked > user_lock_limit) {
6108 * charge locked_vm until it hits user_lock_limit;
6109 * charge the rest from pinned_vm
6111 extra = user_locked - user_lock_limit;
6112 user_extra -= extra;
6115 lock_limit = rlimit(RLIMIT_MEMLOCK);
6116 lock_limit >>= PAGE_SHIFT;
6117 locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
6119 if ((locked > lock_limit) && perf_is_paranoid() &&
6120 !capable(CAP_IPC_LOCK)) {
6125 WARN_ON(!rb && event->rb);
6127 if (vma->vm_flags & VM_WRITE)
6128 flags |= RING_BUFFER_WRITABLE;
6131 rb = rb_alloc(nr_pages,
6132 event->attr.watermark ? event->attr.wakeup_watermark : 0,
6140 atomic_set(&rb->mmap_count, 1);
6141 rb->mmap_user = get_current_user();
6142 rb->mmap_locked = extra;
6144 ring_buffer_attach(event, rb);
6146 perf_event_init_userpage(event);
6147 perf_event_update_userpage(event);
6149 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
6150 event->attr.aux_watermark, flags);
6152 rb->aux_mmap_locked = extra;
6157 atomic_long_add(user_extra, &user->locked_vm);
6158 atomic64_add(extra, &vma->vm_mm->pinned_vm);
6160 atomic_inc(&event->mmap_count);
6162 atomic_dec(&rb->mmap_count);
6165 mutex_unlock(&event->mmap_mutex);
6168 * Since pinned accounting is per vm we cannot allow fork() to copy our
6171 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
6172 vma->vm_ops = &perf_mmap_vmops;
6174 if (event->pmu->event_mapped)
6175 event->pmu->event_mapped(event, vma->vm_mm);
6180 static int perf_fasync(int fd, struct file *filp, int on)
6182 struct inode *inode = file_inode(filp);
6183 struct perf_event *event = filp->private_data;
6187 retval = fasync_helper(fd, filp, on, &event->fasync);
6188 inode_unlock(inode);
6196 static const struct file_operations perf_fops = {
6197 .llseek = no_llseek,
6198 .release = perf_release,
6201 .unlocked_ioctl = perf_ioctl,
6202 .compat_ioctl = perf_compat_ioctl,
6204 .fasync = perf_fasync,
6210 * If there's data, ensure we set the poll() state and publish everything
6211 * to user-space before waking everybody up.
6214 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
6216 /* only the parent has fasync state */
6218 event = event->parent;
6219 return &event->fasync;
6222 void perf_event_wakeup(struct perf_event *event)
6224 ring_buffer_wakeup(event);
6226 if (event->pending_kill) {
6227 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
6228 event->pending_kill = 0;
6232 static void perf_pending_event_disable(struct perf_event *event)
6234 int cpu = READ_ONCE(event->pending_disable);
6239 if (cpu == smp_processor_id()) {
6240 WRITE_ONCE(event->pending_disable, -1);
6241 perf_event_disable_local(event);
6248 * perf_event_disable_inatomic()
6249 * @pending_disable = CPU-A;
6253 * @pending_disable = -1;
6256 * perf_event_disable_inatomic()
6257 * @pending_disable = CPU-B;
6258 * irq_work_queue(); // FAILS
6261 * perf_pending_event()
6263 * But the event runs on CPU-B and wants disabling there.
6265 irq_work_queue_on(&event->pending, cpu);
6268 static void perf_pending_event(struct irq_work *entry)
6270 struct perf_event *event = container_of(entry, struct perf_event, pending);
6273 rctx = perf_swevent_get_recursion_context();
6275 * If we 'fail' here, that's OK, it means recursion is already disabled
6276 * and we won't recurse 'further'.
6279 perf_pending_event_disable(event);
6281 if (event->pending_wakeup) {
6282 event->pending_wakeup = 0;
6283 perf_event_wakeup(event);
6287 perf_swevent_put_recursion_context(rctx);
6291 * We assume there is only KVM supporting the callbacks.
6292 * Later on, we might change it to a list if there is
6293 * another virtualization implementation supporting the callbacks.
6295 struct perf_guest_info_callbacks *perf_guest_cbs;
6297 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6299 perf_guest_cbs = cbs;
6302 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6304 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6306 perf_guest_cbs = NULL;
6309 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6312 perf_output_sample_regs(struct perf_output_handle *handle,
6313 struct pt_regs *regs, u64 mask)
6316 DECLARE_BITMAP(_mask, 64);
6318 bitmap_from_u64(_mask, mask);
6319 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6322 val = perf_reg_value(regs, bit);
6323 perf_output_put(handle, val);
6327 static void perf_sample_regs_user(struct perf_regs *regs_user,
6328 struct pt_regs *regs,
6329 struct pt_regs *regs_user_copy)
6331 if (user_mode(regs)) {
6332 regs_user->abi = perf_reg_abi(current);
6333 regs_user->regs = regs;
6334 } else if (!(current->flags & PF_KTHREAD)) {
6335 perf_get_regs_user(regs_user, regs, regs_user_copy);
6337 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6338 regs_user->regs = NULL;
6342 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6343 struct pt_regs *regs)
6345 regs_intr->regs = regs;
6346 regs_intr->abi = perf_reg_abi(current);
6351 * Get remaining task size from user stack pointer.
6353 * It'd be better to take stack vma map and limit this more
6354 * precisely, but there's no way to get it safely under interrupt,
6355 * so using TASK_SIZE as limit.
6357 static u64 perf_ustack_task_size(struct pt_regs *regs)
6359 unsigned long addr = perf_user_stack_pointer(regs);
6361 if (!addr || addr >= TASK_SIZE)
6364 return TASK_SIZE - addr;
6368 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6369 struct pt_regs *regs)
6373 /* No regs, no stack pointer, no dump. */
6378 * Check if we fit in with the requested stack size into the:
6380 * If we don't, we limit the size to the TASK_SIZE.
6382 * - remaining sample size
6383 * If we don't, we customize the stack size to
6384 * fit in to the remaining sample size.
6387 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6388 stack_size = min(stack_size, (u16) task_size);
6390 /* Current header size plus static size and dynamic size. */
6391 header_size += 2 * sizeof(u64);
6393 /* Do we fit in with the current stack dump size? */
6394 if ((u16) (header_size + stack_size) < header_size) {
6396 * If we overflow the maximum size for the sample,
6397 * we customize the stack dump size to fit in.
6399 stack_size = USHRT_MAX - header_size - sizeof(u64);
6400 stack_size = round_up(stack_size, sizeof(u64));
6407 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6408 struct pt_regs *regs)
6410 /* Case of a kernel thread, nothing to dump */
6413 perf_output_put(handle, size);
6423 * - the size requested by user or the best one we can fit
6424 * in to the sample max size
6426 * - user stack dump data
6428 * - the actual dumped size
6432 perf_output_put(handle, dump_size);
6435 sp = perf_user_stack_pointer(regs);
6438 rem = __output_copy_user(handle, (void *) sp, dump_size);
6440 dyn_size = dump_size - rem;
6442 perf_output_skip(handle, rem);
6445 perf_output_put(handle, dyn_size);
6449 static unsigned long perf_prepare_sample_aux(struct perf_event *event,
6450 struct perf_sample_data *data,
6453 struct perf_event *sampler = event->aux_event;
6454 struct perf_buffer *rb;
6461 if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
6464 if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
6467 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6472 * If this is an NMI hit inside sampling code, don't take
6473 * the sample. See also perf_aux_sample_output().
6475 if (READ_ONCE(rb->aux_in_sampling)) {
6478 size = min_t(size_t, size, perf_aux_size(rb));
6479 data->aux_size = ALIGN(size, sizeof(u64));
6481 ring_buffer_put(rb);
6484 return data->aux_size;
6487 long perf_pmu_snapshot_aux(struct perf_buffer *rb,
6488 struct perf_event *event,
6489 struct perf_output_handle *handle,
6492 unsigned long flags;
6496 * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
6497 * paths. If we start calling them in NMI context, they may race with
6498 * the IRQ ones, that is, for example, re-starting an event that's just
6499 * been stopped, which is why we're using a separate callback that
6500 * doesn't change the event state.
6502 * IRQs need to be disabled to prevent IPIs from racing with us.
6504 local_irq_save(flags);
6506 * Guard against NMI hits inside the critical section;
6507 * see also perf_prepare_sample_aux().
6509 WRITE_ONCE(rb->aux_in_sampling, 1);
6512 ret = event->pmu->snapshot_aux(event, handle, size);
6515 WRITE_ONCE(rb->aux_in_sampling, 0);
6516 local_irq_restore(flags);
6521 static void perf_aux_sample_output(struct perf_event *event,
6522 struct perf_output_handle *handle,
6523 struct perf_sample_data *data)
6525 struct perf_event *sampler = event->aux_event;
6526 struct perf_buffer *rb;
6530 if (WARN_ON_ONCE(!sampler || !data->aux_size))
6533 rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6537 size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
6540 * An error here means that perf_output_copy() failed (returned a
6541 * non-zero surplus that it didn't copy), which in its current
6542 * enlightened implementation is not possible. If that changes, we'd
6545 if (WARN_ON_ONCE(size < 0))
6549 * The pad comes from ALIGN()ing data->aux_size up to u64 in
6550 * perf_prepare_sample_aux(), so should not be more than that.
6552 pad = data->aux_size - size;
6553 if (WARN_ON_ONCE(pad >= sizeof(u64)))
6558 perf_output_copy(handle, &zero, pad);
6562 ring_buffer_put(rb);
6565 static void __perf_event_header__init_id(struct perf_event_header *header,
6566 struct perf_sample_data *data,
6567 struct perf_event *event)
6569 u64 sample_type = event->attr.sample_type;
6571 data->type = sample_type;
6572 header->size += event->id_header_size;
6574 if (sample_type & PERF_SAMPLE_TID) {
6575 /* namespace issues */
6576 data->tid_entry.pid = perf_event_pid(event, current);
6577 data->tid_entry.tid = perf_event_tid(event, current);
6580 if (sample_type & PERF_SAMPLE_TIME)
6581 data->time = perf_event_clock(event);
6583 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6584 data->id = primary_event_id(event);
6586 if (sample_type & PERF_SAMPLE_STREAM_ID)
6587 data->stream_id = event->id;
6589 if (sample_type & PERF_SAMPLE_CPU) {
6590 data->cpu_entry.cpu = raw_smp_processor_id();
6591 data->cpu_entry.reserved = 0;
6595 void perf_event_header__init_id(struct perf_event_header *header,
6596 struct perf_sample_data *data,
6597 struct perf_event *event)
6599 if (event->attr.sample_id_all)
6600 __perf_event_header__init_id(header, data, event);
6603 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6604 struct perf_sample_data *data)
6606 u64 sample_type = data->type;
6608 if (sample_type & PERF_SAMPLE_TID)
6609 perf_output_put(handle, data->tid_entry);
6611 if (sample_type & PERF_SAMPLE_TIME)
6612 perf_output_put(handle, data->time);
6614 if (sample_type & PERF_SAMPLE_ID)
6615 perf_output_put(handle, data->id);
6617 if (sample_type & PERF_SAMPLE_STREAM_ID)
6618 perf_output_put(handle, data->stream_id);
6620 if (sample_type & PERF_SAMPLE_CPU)
6621 perf_output_put(handle, data->cpu_entry);
6623 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6624 perf_output_put(handle, data->id);
6627 void perf_event__output_id_sample(struct perf_event *event,
6628 struct perf_output_handle *handle,
6629 struct perf_sample_data *sample)
6631 if (event->attr.sample_id_all)
6632 __perf_event__output_id_sample(handle, sample);
6635 static void perf_output_read_one(struct perf_output_handle *handle,
6636 struct perf_event *event,
6637 u64 enabled, u64 running)
6639 u64 read_format = event->attr.read_format;
6643 values[n++] = perf_event_count(event);
6644 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6645 values[n++] = enabled +
6646 atomic64_read(&event->child_total_time_enabled);
6648 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6649 values[n++] = running +
6650 atomic64_read(&event->child_total_time_running);
6652 if (read_format & PERF_FORMAT_ID)
6653 values[n++] = primary_event_id(event);
6655 __output_copy(handle, values, n * sizeof(u64));
6658 static void perf_output_read_group(struct perf_output_handle *handle,
6659 struct perf_event *event,
6660 u64 enabled, u64 running)
6662 struct perf_event *leader = event->group_leader, *sub;
6663 u64 read_format = event->attr.read_format;
6667 values[n++] = 1 + leader->nr_siblings;
6669 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6670 values[n++] = enabled;
6672 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6673 values[n++] = running;
6675 if ((leader != event) &&
6676 (leader->state == PERF_EVENT_STATE_ACTIVE))
6677 leader->pmu->read(leader);
6679 values[n++] = perf_event_count(leader);
6680 if (read_format & PERF_FORMAT_ID)
6681 values[n++] = primary_event_id(leader);
6683 __output_copy(handle, values, n * sizeof(u64));
6685 for_each_sibling_event(sub, leader) {
6688 if ((sub != event) &&
6689 (sub->state == PERF_EVENT_STATE_ACTIVE))
6690 sub->pmu->read(sub);
6692 values[n++] = perf_event_count(sub);
6693 if (read_format & PERF_FORMAT_ID)
6694 values[n++] = primary_event_id(sub);
6696 __output_copy(handle, values, n * sizeof(u64));
6700 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6701 PERF_FORMAT_TOTAL_TIME_RUNNING)
6704 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6706 * The problem is that its both hard and excessively expensive to iterate the
6707 * child list, not to mention that its impossible to IPI the children running
6708 * on another CPU, from interrupt/NMI context.
6710 static void perf_output_read(struct perf_output_handle *handle,
6711 struct perf_event *event)
6713 u64 enabled = 0, running = 0, now;
6714 u64 read_format = event->attr.read_format;
6717 * compute total_time_enabled, total_time_running
6718 * based on snapshot values taken when the event
6719 * was last scheduled in.
6721 * we cannot simply called update_context_time()
6722 * because of locking issue as we are called in
6725 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6726 calc_timer_values(event, &now, &enabled, &running);
6728 if (event->attr.read_format & PERF_FORMAT_GROUP)
6729 perf_output_read_group(handle, event, enabled, running);
6731 perf_output_read_one(handle, event, enabled, running);
6734 static inline bool perf_sample_save_hw_index(struct perf_event *event)
6736 return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_HW_INDEX;
6739 void perf_output_sample(struct perf_output_handle *handle,
6740 struct perf_event_header *header,
6741 struct perf_sample_data *data,
6742 struct perf_event *event)
6744 u64 sample_type = data->type;
6746 perf_output_put(handle, *header);
6748 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6749 perf_output_put(handle, data->id);
6751 if (sample_type & PERF_SAMPLE_IP)
6752 perf_output_put(handle, data->ip);
6754 if (sample_type & PERF_SAMPLE_TID)
6755 perf_output_put(handle, data->tid_entry);
6757 if (sample_type & PERF_SAMPLE_TIME)
6758 perf_output_put(handle, data->time);
6760 if (sample_type & PERF_SAMPLE_ADDR)
6761 perf_output_put(handle, data->addr);
6763 if (sample_type & PERF_SAMPLE_ID)
6764 perf_output_put(handle, data->id);
6766 if (sample_type & PERF_SAMPLE_STREAM_ID)
6767 perf_output_put(handle, data->stream_id);
6769 if (sample_type & PERF_SAMPLE_CPU)
6770 perf_output_put(handle, data->cpu_entry);
6772 if (sample_type & PERF_SAMPLE_PERIOD)
6773 perf_output_put(handle, data->period);
6775 if (sample_type & PERF_SAMPLE_READ)
6776 perf_output_read(handle, event);
6778 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6781 size += data->callchain->nr;
6782 size *= sizeof(u64);
6783 __output_copy(handle, data->callchain, size);
6786 if (sample_type & PERF_SAMPLE_RAW) {
6787 struct perf_raw_record *raw = data->raw;
6790 struct perf_raw_frag *frag = &raw->frag;
6792 perf_output_put(handle, raw->size);
6795 __output_custom(handle, frag->copy,
6796 frag->data, frag->size);
6798 __output_copy(handle, frag->data,
6801 if (perf_raw_frag_last(frag))
6806 __output_skip(handle, NULL, frag->pad);
6812 .size = sizeof(u32),
6815 perf_output_put(handle, raw);
6819 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6820 if (data->br_stack) {
6823 size = data->br_stack->nr
6824 * sizeof(struct perf_branch_entry);
6826 perf_output_put(handle, data->br_stack->nr);
6827 if (perf_sample_save_hw_index(event))
6828 perf_output_put(handle, data->br_stack->hw_idx);
6829 perf_output_copy(handle, data->br_stack->entries, size);
6832 * we always store at least the value of nr
6835 perf_output_put(handle, nr);
6839 if (sample_type & PERF_SAMPLE_REGS_USER) {
6840 u64 abi = data->regs_user.abi;
6843 * If there are no regs to dump, notice it through
6844 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6846 perf_output_put(handle, abi);
6849 u64 mask = event->attr.sample_regs_user;
6850 perf_output_sample_regs(handle,
6851 data->regs_user.regs,
6856 if (sample_type & PERF_SAMPLE_STACK_USER) {
6857 perf_output_sample_ustack(handle,
6858 data->stack_user_size,
6859 data->regs_user.regs);
6862 if (sample_type & PERF_SAMPLE_WEIGHT)
6863 perf_output_put(handle, data->weight);
6865 if (sample_type & PERF_SAMPLE_DATA_SRC)
6866 perf_output_put(handle, data->data_src.val);
6868 if (sample_type & PERF_SAMPLE_TRANSACTION)
6869 perf_output_put(handle, data->txn);
6871 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6872 u64 abi = data->regs_intr.abi;
6874 * If there are no regs to dump, notice it through
6875 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6877 perf_output_put(handle, abi);
6880 u64 mask = event->attr.sample_regs_intr;
6882 perf_output_sample_regs(handle,
6883 data->regs_intr.regs,
6888 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6889 perf_output_put(handle, data->phys_addr);
6891 if (sample_type & PERF_SAMPLE_CGROUP)
6892 perf_output_put(handle, data->cgroup);
6894 if (sample_type & PERF_SAMPLE_AUX) {
6895 perf_output_put(handle, data->aux_size);
6898 perf_aux_sample_output(event, handle, data);
6901 if (!event->attr.watermark) {
6902 int wakeup_events = event->attr.wakeup_events;
6904 if (wakeup_events) {
6905 struct perf_buffer *rb = handle->rb;
6906 int events = local_inc_return(&rb->events);
6908 if (events >= wakeup_events) {
6909 local_sub(wakeup_events, &rb->events);
6910 local_inc(&rb->wakeup);
6916 static u64 perf_virt_to_phys(u64 virt)
6919 struct page *p = NULL;
6924 if (virt >= TASK_SIZE) {
6925 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6926 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6927 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6928 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6931 * Walking the pages tables for user address.
6932 * Interrupts are disabled, so it prevents any tear down
6933 * of the page tables.
6934 * Try IRQ-safe __get_user_pages_fast first.
6935 * If failed, leave phys_addr as 0.
6937 if (current->mm != NULL) {
6938 pagefault_disable();
6939 if (__get_user_pages_fast(virt, 1, 0, &p) == 1)
6940 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6951 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6953 struct perf_callchain_entry *
6954 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6956 bool kernel = !event->attr.exclude_callchain_kernel;
6957 bool user = !event->attr.exclude_callchain_user;
6958 /* Disallow cross-task user callchains. */
6959 bool crosstask = event->ctx->task && event->ctx->task != current;
6960 const u32 max_stack = event->attr.sample_max_stack;
6961 struct perf_callchain_entry *callchain;
6963 if (!kernel && !user)
6964 return &__empty_callchain;
6966 callchain = get_perf_callchain(regs, 0, kernel, user,
6967 max_stack, crosstask, true);
6968 return callchain ?: &__empty_callchain;
6971 void perf_prepare_sample(struct perf_event_header *header,
6972 struct perf_sample_data *data,
6973 struct perf_event *event,
6974 struct pt_regs *regs)
6976 u64 sample_type = event->attr.sample_type;
6978 header->type = PERF_RECORD_SAMPLE;
6979 header->size = sizeof(*header) + event->header_size;
6982 header->misc |= perf_misc_flags(regs);
6984 __perf_event_header__init_id(header, data, event);
6986 if (sample_type & PERF_SAMPLE_IP)
6987 data->ip = perf_instruction_pointer(regs);
6989 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6992 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6993 data->callchain = perf_callchain(event, regs);
6995 size += data->callchain->nr;
6997 header->size += size * sizeof(u64);
7000 if (sample_type & PERF_SAMPLE_RAW) {
7001 struct perf_raw_record *raw = data->raw;
7005 struct perf_raw_frag *frag = &raw->frag;
7010 if (perf_raw_frag_last(frag))
7015 size = round_up(sum + sizeof(u32), sizeof(u64));
7016 raw->size = size - sizeof(u32);
7017 frag->pad = raw->size - sum;
7022 header->size += size;
7025 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7026 int size = sizeof(u64); /* nr */
7027 if (data->br_stack) {
7028 if (perf_sample_save_hw_index(event))
7029 size += sizeof(u64);
7031 size += data->br_stack->nr
7032 * sizeof(struct perf_branch_entry);
7034 header->size += size;
7037 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
7038 perf_sample_regs_user(&data->regs_user, regs,
7039 &data->regs_user_copy);
7041 if (sample_type & PERF_SAMPLE_REGS_USER) {
7042 /* regs dump ABI info */
7043 int size = sizeof(u64);
7045 if (data->regs_user.regs) {
7046 u64 mask = event->attr.sample_regs_user;
7047 size += hweight64(mask) * sizeof(u64);
7050 header->size += size;
7053 if (sample_type & PERF_SAMPLE_STACK_USER) {
7055 * Either we need PERF_SAMPLE_STACK_USER bit to be always
7056 * processed as the last one or have additional check added
7057 * in case new sample type is added, because we could eat
7058 * up the rest of the sample size.
7060 u16 stack_size = event->attr.sample_stack_user;
7061 u16 size = sizeof(u64);
7063 stack_size = perf_sample_ustack_size(stack_size, header->size,
7064 data->regs_user.regs);
7067 * If there is something to dump, add space for the dump
7068 * itself and for the field that tells the dynamic size,
7069 * which is how many have been actually dumped.
7072 size += sizeof(u64) + stack_size;
7074 data->stack_user_size = stack_size;
7075 header->size += size;
7078 if (sample_type & PERF_SAMPLE_REGS_INTR) {
7079 /* regs dump ABI info */
7080 int size = sizeof(u64);
7082 perf_sample_regs_intr(&data->regs_intr, regs);
7084 if (data->regs_intr.regs) {
7085 u64 mask = event->attr.sample_regs_intr;
7087 size += hweight64(mask) * sizeof(u64);
7090 header->size += size;
7093 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7094 data->phys_addr = perf_virt_to_phys(data->addr);
7096 #ifdef CONFIG_CGROUP_PERF
7097 if (sample_type & PERF_SAMPLE_CGROUP) {
7098 struct cgroup *cgrp;
7100 /* protected by RCU */
7101 cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup;
7102 data->cgroup = cgroup_id(cgrp);
7106 if (sample_type & PERF_SAMPLE_AUX) {
7109 header->size += sizeof(u64); /* size */
7112 * Given the 16bit nature of header::size, an AUX sample can
7113 * easily overflow it, what with all the preceding sample bits.
7114 * Make sure this doesn't happen by using up to U16_MAX bytes
7115 * per sample in total (rounded down to 8 byte boundary).
7117 size = min_t(size_t, U16_MAX - header->size,
7118 event->attr.aux_sample_size);
7119 size = rounddown(size, 8);
7120 size = perf_prepare_sample_aux(event, data, size);
7122 WARN_ON_ONCE(size + header->size > U16_MAX);
7123 header->size += size;
7126 * If you're adding more sample types here, you likely need to do
7127 * something about the overflowing header::size, like repurpose the
7128 * lowest 3 bits of size, which should be always zero at the moment.
7129 * This raises a more important question, do we really need 512k sized
7130 * samples and why, so good argumentation is in order for whatever you
7133 WARN_ON_ONCE(header->size & 7);
7136 static __always_inline int
7137 __perf_event_output(struct perf_event *event,
7138 struct perf_sample_data *data,
7139 struct pt_regs *regs,
7140 int (*output_begin)(struct perf_output_handle *,
7141 struct perf_event *,
7144 struct perf_output_handle handle;
7145 struct perf_event_header header;
7148 /* protect the callchain buffers */
7151 perf_prepare_sample(&header, data, event, regs);
7153 err = output_begin(&handle, event, header.size);
7157 perf_output_sample(&handle, &header, data, event);
7159 perf_output_end(&handle);
7167 perf_event_output_forward(struct perf_event *event,
7168 struct perf_sample_data *data,
7169 struct pt_regs *regs)
7171 __perf_event_output(event, data, regs, perf_output_begin_forward);
7175 perf_event_output_backward(struct perf_event *event,
7176 struct perf_sample_data *data,
7177 struct pt_regs *regs)
7179 __perf_event_output(event, data, regs, perf_output_begin_backward);
7183 perf_event_output(struct perf_event *event,
7184 struct perf_sample_data *data,
7185 struct pt_regs *regs)
7187 return __perf_event_output(event, data, regs, perf_output_begin);
7194 struct perf_read_event {
7195 struct perf_event_header header;
7202 perf_event_read_event(struct perf_event *event,
7203 struct task_struct *task)
7205 struct perf_output_handle handle;
7206 struct perf_sample_data sample;
7207 struct perf_read_event read_event = {
7209 .type = PERF_RECORD_READ,
7211 .size = sizeof(read_event) + event->read_size,
7213 .pid = perf_event_pid(event, task),
7214 .tid = perf_event_tid(event, task),
7218 perf_event_header__init_id(&read_event.header, &sample, event);
7219 ret = perf_output_begin(&handle, event, read_event.header.size);
7223 perf_output_put(&handle, read_event);
7224 perf_output_read(&handle, event);
7225 perf_event__output_id_sample(event, &handle, &sample);
7227 perf_output_end(&handle);
7230 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
7233 perf_iterate_ctx(struct perf_event_context *ctx,
7234 perf_iterate_f output,
7235 void *data, bool all)
7237 struct perf_event *event;
7239 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7241 if (event->state < PERF_EVENT_STATE_INACTIVE)
7243 if (!event_filter_match(event))
7247 output(event, data);
7251 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
7253 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
7254 struct perf_event *event;
7256 list_for_each_entry_rcu(event, &pel->list, sb_list) {
7258 * Skip events that are not fully formed yet; ensure that
7259 * if we observe event->ctx, both event and ctx will be
7260 * complete enough. See perf_install_in_context().
7262 if (!smp_load_acquire(&event->ctx))
7265 if (event->state < PERF_EVENT_STATE_INACTIVE)
7267 if (!event_filter_match(event))
7269 output(event, data);
7274 * Iterate all events that need to receive side-band events.
7276 * For new callers; ensure that account_pmu_sb_event() includes
7277 * your event, otherwise it might not get delivered.
7280 perf_iterate_sb(perf_iterate_f output, void *data,
7281 struct perf_event_context *task_ctx)
7283 struct perf_event_context *ctx;
7290 * If we have task_ctx != NULL we only notify the task context itself.
7291 * The task_ctx is set only for EXIT events before releasing task
7295 perf_iterate_ctx(task_ctx, output, data, false);
7299 perf_iterate_sb_cpu(output, data);
7301 for_each_task_context_nr(ctxn) {
7302 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7304 perf_iterate_ctx(ctx, output, data, false);
7312 * Clear all file-based filters at exec, they'll have to be
7313 * re-instated when/if these objects are mmapped again.
7315 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
7317 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7318 struct perf_addr_filter *filter;
7319 unsigned int restart = 0, count = 0;
7320 unsigned long flags;
7322 if (!has_addr_filter(event))
7325 raw_spin_lock_irqsave(&ifh->lock, flags);
7326 list_for_each_entry(filter, &ifh->list, entry) {
7327 if (filter->path.dentry) {
7328 event->addr_filter_ranges[count].start = 0;
7329 event->addr_filter_ranges[count].size = 0;
7337 event->addr_filters_gen++;
7338 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7341 perf_event_stop(event, 1);
7344 void perf_event_exec(void)
7346 struct perf_event_context *ctx;
7350 for_each_task_context_nr(ctxn) {
7351 ctx = current->perf_event_ctxp[ctxn];
7355 perf_event_enable_on_exec(ctxn);
7357 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
7363 struct remote_output {
7364 struct perf_buffer *rb;
7368 static void __perf_event_output_stop(struct perf_event *event, void *data)
7370 struct perf_event *parent = event->parent;
7371 struct remote_output *ro = data;
7372 struct perf_buffer *rb = ro->rb;
7373 struct stop_event_data sd = {
7377 if (!has_aux(event))
7384 * In case of inheritance, it will be the parent that links to the
7385 * ring-buffer, but it will be the child that's actually using it.
7387 * We are using event::rb to determine if the event should be stopped,
7388 * however this may race with ring_buffer_attach() (through set_output),
7389 * which will make us skip the event that actually needs to be stopped.
7390 * So ring_buffer_attach() has to stop an aux event before re-assigning
7393 if (rcu_dereference(parent->rb) == rb)
7394 ro->err = __perf_event_stop(&sd);
7397 static int __perf_pmu_output_stop(void *info)
7399 struct perf_event *event = info;
7400 struct pmu *pmu = event->ctx->pmu;
7401 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
7402 struct remote_output ro = {
7407 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
7408 if (cpuctx->task_ctx)
7409 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
7416 static void perf_pmu_output_stop(struct perf_event *event)
7418 struct perf_event *iter;
7423 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
7425 * For per-CPU events, we need to make sure that neither they
7426 * nor their children are running; for cpu==-1 events it's
7427 * sufficient to stop the event itself if it's active, since
7428 * it can't have children.
7432 cpu = READ_ONCE(iter->oncpu);
7437 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
7438 if (err == -EAGAIN) {
7447 * task tracking -- fork/exit
7449 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
7452 struct perf_task_event {
7453 struct task_struct *task;
7454 struct perf_event_context *task_ctx;
7457 struct perf_event_header header;
7467 static int perf_event_task_match(struct perf_event *event)
7469 return event->attr.comm || event->attr.mmap ||
7470 event->attr.mmap2 || event->attr.mmap_data ||
7474 static void perf_event_task_output(struct perf_event *event,
7477 struct perf_task_event *task_event = data;
7478 struct perf_output_handle handle;
7479 struct perf_sample_data sample;
7480 struct task_struct *task = task_event->task;
7481 int ret, size = task_event->event_id.header.size;
7483 if (!perf_event_task_match(event))
7486 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
7488 ret = perf_output_begin(&handle, event,
7489 task_event->event_id.header.size);
7493 task_event->event_id.pid = perf_event_pid(event, task);
7494 task_event->event_id.tid = perf_event_tid(event, task);
7496 if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
7497 task_event->event_id.ppid = perf_event_pid(event,
7499 task_event->event_id.ptid = perf_event_pid(event,
7501 } else { /* PERF_RECORD_FORK */
7502 task_event->event_id.ppid = perf_event_pid(event, current);
7503 task_event->event_id.ptid = perf_event_tid(event, current);
7506 task_event->event_id.time = perf_event_clock(event);
7508 perf_output_put(&handle, task_event->event_id);
7510 perf_event__output_id_sample(event, &handle, &sample);
7512 perf_output_end(&handle);
7514 task_event->event_id.header.size = size;
7517 static void perf_event_task(struct task_struct *task,
7518 struct perf_event_context *task_ctx,
7521 struct perf_task_event task_event;
7523 if (!atomic_read(&nr_comm_events) &&
7524 !atomic_read(&nr_mmap_events) &&
7525 !atomic_read(&nr_task_events))
7528 task_event = (struct perf_task_event){
7530 .task_ctx = task_ctx,
7533 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7535 .size = sizeof(task_event.event_id),
7545 perf_iterate_sb(perf_event_task_output,
7550 void perf_event_fork(struct task_struct *task)
7552 perf_event_task(task, NULL, 1);
7553 perf_event_namespaces(task);
7560 struct perf_comm_event {
7561 struct task_struct *task;
7566 struct perf_event_header header;
7573 static int perf_event_comm_match(struct perf_event *event)
7575 return event->attr.comm;
7578 static void perf_event_comm_output(struct perf_event *event,
7581 struct perf_comm_event *comm_event = data;
7582 struct perf_output_handle handle;
7583 struct perf_sample_data sample;
7584 int size = comm_event->event_id.header.size;
7587 if (!perf_event_comm_match(event))
7590 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7591 ret = perf_output_begin(&handle, event,
7592 comm_event->event_id.header.size);
7597 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7598 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7600 perf_output_put(&handle, comm_event->event_id);
7601 __output_copy(&handle, comm_event->comm,
7602 comm_event->comm_size);
7604 perf_event__output_id_sample(event, &handle, &sample);
7606 perf_output_end(&handle);
7608 comm_event->event_id.header.size = size;
7611 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7613 char comm[TASK_COMM_LEN];
7616 memset(comm, 0, sizeof(comm));
7617 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7618 size = ALIGN(strlen(comm)+1, sizeof(u64));
7620 comm_event->comm = comm;
7621 comm_event->comm_size = size;
7623 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7625 perf_iterate_sb(perf_event_comm_output,
7630 void perf_event_comm(struct task_struct *task, bool exec)
7632 struct perf_comm_event comm_event;
7634 if (!atomic_read(&nr_comm_events))
7637 comm_event = (struct perf_comm_event){
7643 .type = PERF_RECORD_COMM,
7644 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7652 perf_event_comm_event(&comm_event);
7656 * namespaces tracking
7659 struct perf_namespaces_event {
7660 struct task_struct *task;
7663 struct perf_event_header header;
7668 struct perf_ns_link_info link_info[NR_NAMESPACES];
7672 static int perf_event_namespaces_match(struct perf_event *event)
7674 return event->attr.namespaces;
7677 static void perf_event_namespaces_output(struct perf_event *event,
7680 struct perf_namespaces_event *namespaces_event = data;
7681 struct perf_output_handle handle;
7682 struct perf_sample_data sample;
7683 u16 header_size = namespaces_event->event_id.header.size;
7686 if (!perf_event_namespaces_match(event))
7689 perf_event_header__init_id(&namespaces_event->event_id.header,
7691 ret = perf_output_begin(&handle, event,
7692 namespaces_event->event_id.header.size);
7696 namespaces_event->event_id.pid = perf_event_pid(event,
7697 namespaces_event->task);
7698 namespaces_event->event_id.tid = perf_event_tid(event,
7699 namespaces_event->task);
7701 perf_output_put(&handle, namespaces_event->event_id);
7703 perf_event__output_id_sample(event, &handle, &sample);
7705 perf_output_end(&handle);
7707 namespaces_event->event_id.header.size = header_size;
7710 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7711 struct task_struct *task,
7712 const struct proc_ns_operations *ns_ops)
7714 struct path ns_path;
7715 struct inode *ns_inode;
7718 error = ns_get_path(&ns_path, task, ns_ops);
7720 ns_inode = ns_path.dentry->d_inode;
7721 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7722 ns_link_info->ino = ns_inode->i_ino;
7727 void perf_event_namespaces(struct task_struct *task)
7729 struct perf_namespaces_event namespaces_event;
7730 struct perf_ns_link_info *ns_link_info;
7732 if (!atomic_read(&nr_namespaces_events))
7735 namespaces_event = (struct perf_namespaces_event){
7739 .type = PERF_RECORD_NAMESPACES,
7741 .size = sizeof(namespaces_event.event_id),
7745 .nr_namespaces = NR_NAMESPACES,
7746 /* .link_info[NR_NAMESPACES] */
7750 ns_link_info = namespaces_event.event_id.link_info;
7752 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7753 task, &mntns_operations);
7755 #ifdef CONFIG_USER_NS
7756 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7757 task, &userns_operations);
7759 #ifdef CONFIG_NET_NS
7760 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7761 task, &netns_operations);
7763 #ifdef CONFIG_UTS_NS
7764 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7765 task, &utsns_operations);
7767 #ifdef CONFIG_IPC_NS
7768 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7769 task, &ipcns_operations);
7771 #ifdef CONFIG_PID_NS
7772 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7773 task, &pidns_operations);
7775 #ifdef CONFIG_CGROUPS
7776 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7777 task, &cgroupns_operations);
7780 perf_iterate_sb(perf_event_namespaces_output,
7788 #ifdef CONFIG_CGROUP_PERF
7790 struct perf_cgroup_event {
7794 struct perf_event_header header;
7800 static int perf_event_cgroup_match(struct perf_event *event)
7802 return event->attr.cgroup;
7805 static void perf_event_cgroup_output(struct perf_event *event, void *data)
7807 struct perf_cgroup_event *cgroup_event = data;
7808 struct perf_output_handle handle;
7809 struct perf_sample_data sample;
7810 u16 header_size = cgroup_event->event_id.header.size;
7813 if (!perf_event_cgroup_match(event))
7816 perf_event_header__init_id(&cgroup_event->event_id.header,
7818 ret = perf_output_begin(&handle, event,
7819 cgroup_event->event_id.header.size);
7823 perf_output_put(&handle, cgroup_event->event_id);
7824 __output_copy(&handle, cgroup_event->path, cgroup_event->path_size);
7826 perf_event__output_id_sample(event, &handle, &sample);
7828 perf_output_end(&handle);
7830 cgroup_event->event_id.header.size = header_size;
7833 static void perf_event_cgroup(struct cgroup *cgrp)
7835 struct perf_cgroup_event cgroup_event;
7836 char path_enomem[16] = "//enomem";
7840 if (!atomic_read(&nr_cgroup_events))
7843 cgroup_event = (struct perf_cgroup_event){
7846 .type = PERF_RECORD_CGROUP,
7848 .size = sizeof(cgroup_event.event_id),
7850 .id = cgroup_id(cgrp),
7854 pathname = kmalloc(PATH_MAX, GFP_KERNEL);
7855 if (pathname == NULL) {
7856 cgroup_event.path = path_enomem;
7858 /* just to be sure to have enough space for alignment */
7859 cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64));
7860 cgroup_event.path = pathname;
7864 * Since our buffer works in 8 byte units we need to align our string
7865 * size to a multiple of 8. However, we must guarantee the tail end is
7866 * zero'd out to avoid leaking random bits to userspace.
7868 size = strlen(cgroup_event.path) + 1;
7869 while (!IS_ALIGNED(size, sizeof(u64)))
7870 cgroup_event.path[size++] = '\0';
7872 cgroup_event.event_id.header.size += size;
7873 cgroup_event.path_size = size;
7875 perf_iterate_sb(perf_event_cgroup_output,
7888 struct perf_mmap_event {
7889 struct vm_area_struct *vma;
7891 const char *file_name;
7899 struct perf_event_header header;
7909 static int perf_event_mmap_match(struct perf_event *event,
7912 struct perf_mmap_event *mmap_event = data;
7913 struct vm_area_struct *vma = mmap_event->vma;
7914 int executable = vma->vm_flags & VM_EXEC;
7916 return (!executable && event->attr.mmap_data) ||
7917 (executable && (event->attr.mmap || event->attr.mmap2));
7920 static void perf_event_mmap_output(struct perf_event *event,
7923 struct perf_mmap_event *mmap_event = data;
7924 struct perf_output_handle handle;
7925 struct perf_sample_data sample;
7926 int size = mmap_event->event_id.header.size;
7927 u32 type = mmap_event->event_id.header.type;
7930 if (!perf_event_mmap_match(event, data))
7933 if (event->attr.mmap2) {
7934 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7935 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7936 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7937 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7938 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7939 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7940 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7943 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7944 ret = perf_output_begin(&handle, event,
7945 mmap_event->event_id.header.size);
7949 mmap_event->event_id.pid = perf_event_pid(event, current);
7950 mmap_event->event_id.tid = perf_event_tid(event, current);
7952 perf_output_put(&handle, mmap_event->event_id);
7954 if (event->attr.mmap2) {
7955 perf_output_put(&handle, mmap_event->maj);
7956 perf_output_put(&handle, mmap_event->min);
7957 perf_output_put(&handle, mmap_event->ino);
7958 perf_output_put(&handle, mmap_event->ino_generation);
7959 perf_output_put(&handle, mmap_event->prot);
7960 perf_output_put(&handle, mmap_event->flags);
7963 __output_copy(&handle, mmap_event->file_name,
7964 mmap_event->file_size);
7966 perf_event__output_id_sample(event, &handle, &sample);
7968 perf_output_end(&handle);
7970 mmap_event->event_id.header.size = size;
7971 mmap_event->event_id.header.type = type;
7974 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7976 struct vm_area_struct *vma = mmap_event->vma;
7977 struct file *file = vma->vm_file;
7978 int maj = 0, min = 0;
7979 u64 ino = 0, gen = 0;
7980 u32 prot = 0, flags = 0;
7986 if (vma->vm_flags & VM_READ)
7988 if (vma->vm_flags & VM_WRITE)
7990 if (vma->vm_flags & VM_EXEC)
7993 if (vma->vm_flags & VM_MAYSHARE)
7996 flags = MAP_PRIVATE;
7998 if (vma->vm_flags & VM_DENYWRITE)
7999 flags |= MAP_DENYWRITE;
8000 if (vma->vm_flags & VM_MAYEXEC)
8001 flags |= MAP_EXECUTABLE;
8002 if (vma->vm_flags & VM_LOCKED)
8003 flags |= MAP_LOCKED;
8004 if (is_vm_hugetlb_page(vma))
8005 flags |= MAP_HUGETLB;
8008 struct inode *inode;
8011 buf = kmalloc(PATH_MAX, GFP_KERNEL);
8017 * d_path() works from the end of the rb backwards, so we
8018 * need to add enough zero bytes after the string to handle
8019 * the 64bit alignment we do later.
8021 name = file_path(file, buf, PATH_MAX - sizeof(u64));
8026 inode = file_inode(vma->vm_file);
8027 dev = inode->i_sb->s_dev;
8029 gen = inode->i_generation;
8035 if (vma->vm_ops && vma->vm_ops->name) {
8036 name = (char *) vma->vm_ops->name(vma);
8041 name = (char *)arch_vma_name(vma);
8045 if (vma->vm_start <= vma->vm_mm->start_brk &&
8046 vma->vm_end >= vma->vm_mm->brk) {
8050 if (vma->vm_start <= vma->vm_mm->start_stack &&
8051 vma->vm_end >= vma->vm_mm->start_stack) {
8061 strlcpy(tmp, name, sizeof(tmp));
8065 * Since our buffer works in 8 byte units we need to align our string
8066 * size to a multiple of 8. However, we must guarantee the tail end is
8067 * zero'd out to avoid leaking random bits to userspace.
8069 size = strlen(name)+1;
8070 while (!IS_ALIGNED(size, sizeof(u64)))
8071 name[size++] = '\0';
8073 mmap_event->file_name = name;
8074 mmap_event->file_size = size;
8075 mmap_event->maj = maj;
8076 mmap_event->min = min;
8077 mmap_event->ino = ino;
8078 mmap_event->ino_generation = gen;
8079 mmap_event->prot = prot;
8080 mmap_event->flags = flags;
8082 if (!(vma->vm_flags & VM_EXEC))
8083 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
8085 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
8087 perf_iterate_sb(perf_event_mmap_output,
8095 * Check whether inode and address range match filter criteria.
8097 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
8098 struct file *file, unsigned long offset,
8101 /* d_inode(NULL) won't be equal to any mapped user-space file */
8102 if (!filter->path.dentry)
8105 if (d_inode(filter->path.dentry) != file_inode(file))
8108 if (filter->offset > offset + size)
8111 if (filter->offset + filter->size < offset)
8117 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
8118 struct vm_area_struct *vma,
8119 struct perf_addr_filter_range *fr)
8121 unsigned long vma_size = vma->vm_end - vma->vm_start;
8122 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8123 struct file *file = vma->vm_file;
8125 if (!perf_addr_filter_match(filter, file, off, vma_size))
8128 if (filter->offset < off) {
8129 fr->start = vma->vm_start;
8130 fr->size = min(vma_size, filter->size - (off - filter->offset));
8132 fr->start = vma->vm_start + filter->offset - off;
8133 fr->size = min(vma->vm_end - fr->start, filter->size);
8139 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
8141 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8142 struct vm_area_struct *vma = data;
8143 struct perf_addr_filter *filter;
8144 unsigned int restart = 0, count = 0;
8145 unsigned long flags;
8147 if (!has_addr_filter(event))
8153 raw_spin_lock_irqsave(&ifh->lock, flags);
8154 list_for_each_entry(filter, &ifh->list, entry) {
8155 if (perf_addr_filter_vma_adjust(filter, vma,
8156 &event->addr_filter_ranges[count]))
8163 event->addr_filters_gen++;
8164 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8167 perf_event_stop(event, 1);
8171 * Adjust all task's events' filters to the new vma
8173 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
8175 struct perf_event_context *ctx;
8179 * Data tracing isn't supported yet and as such there is no need
8180 * to keep track of anything that isn't related to executable code:
8182 if (!(vma->vm_flags & VM_EXEC))
8186 for_each_task_context_nr(ctxn) {
8187 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
8191 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
8196 void perf_event_mmap(struct vm_area_struct *vma)
8198 struct perf_mmap_event mmap_event;
8200 if (!atomic_read(&nr_mmap_events))
8203 mmap_event = (struct perf_mmap_event){
8209 .type = PERF_RECORD_MMAP,
8210 .misc = PERF_RECORD_MISC_USER,
8215 .start = vma->vm_start,
8216 .len = vma->vm_end - vma->vm_start,
8217 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
8219 /* .maj (attr_mmap2 only) */
8220 /* .min (attr_mmap2 only) */
8221 /* .ino (attr_mmap2 only) */
8222 /* .ino_generation (attr_mmap2 only) */
8223 /* .prot (attr_mmap2 only) */
8224 /* .flags (attr_mmap2 only) */
8227 perf_addr_filters_adjust(vma);
8228 perf_event_mmap_event(&mmap_event);
8231 void perf_event_aux_event(struct perf_event *event, unsigned long head,
8232 unsigned long size, u64 flags)
8234 struct perf_output_handle handle;
8235 struct perf_sample_data sample;
8236 struct perf_aux_event {
8237 struct perf_event_header header;
8243 .type = PERF_RECORD_AUX,
8245 .size = sizeof(rec),
8253 perf_event_header__init_id(&rec.header, &sample, event);
8254 ret = perf_output_begin(&handle, event, rec.header.size);
8259 perf_output_put(&handle, rec);
8260 perf_event__output_id_sample(event, &handle, &sample);
8262 perf_output_end(&handle);
8266 * Lost/dropped samples logging
8268 void perf_log_lost_samples(struct perf_event *event, u64 lost)
8270 struct perf_output_handle handle;
8271 struct perf_sample_data sample;
8275 struct perf_event_header header;
8277 } lost_samples_event = {
8279 .type = PERF_RECORD_LOST_SAMPLES,
8281 .size = sizeof(lost_samples_event),
8286 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
8288 ret = perf_output_begin(&handle, event,
8289 lost_samples_event.header.size);
8293 perf_output_put(&handle, lost_samples_event);
8294 perf_event__output_id_sample(event, &handle, &sample);
8295 perf_output_end(&handle);
8299 * context_switch tracking
8302 struct perf_switch_event {
8303 struct task_struct *task;
8304 struct task_struct *next_prev;
8307 struct perf_event_header header;
8313 static int perf_event_switch_match(struct perf_event *event)
8315 return event->attr.context_switch;
8318 static void perf_event_switch_output(struct perf_event *event, void *data)
8320 struct perf_switch_event *se = data;
8321 struct perf_output_handle handle;
8322 struct perf_sample_data sample;
8325 if (!perf_event_switch_match(event))
8328 /* Only CPU-wide events are allowed to see next/prev pid/tid */
8329 if (event->ctx->task) {
8330 se->event_id.header.type = PERF_RECORD_SWITCH;
8331 se->event_id.header.size = sizeof(se->event_id.header);
8333 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
8334 se->event_id.header.size = sizeof(se->event_id);
8335 se->event_id.next_prev_pid =
8336 perf_event_pid(event, se->next_prev);
8337 se->event_id.next_prev_tid =
8338 perf_event_tid(event, se->next_prev);
8341 perf_event_header__init_id(&se->event_id.header, &sample, event);
8343 ret = perf_output_begin(&handle, event, se->event_id.header.size);
8347 if (event->ctx->task)
8348 perf_output_put(&handle, se->event_id.header);
8350 perf_output_put(&handle, se->event_id);
8352 perf_event__output_id_sample(event, &handle, &sample);
8354 perf_output_end(&handle);
8357 static void perf_event_switch(struct task_struct *task,
8358 struct task_struct *next_prev, bool sched_in)
8360 struct perf_switch_event switch_event;
8362 /* N.B. caller checks nr_switch_events != 0 */
8364 switch_event = (struct perf_switch_event){
8366 .next_prev = next_prev,
8370 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
8373 /* .next_prev_pid */
8374 /* .next_prev_tid */
8378 if (!sched_in && task->state == TASK_RUNNING)
8379 switch_event.event_id.header.misc |=
8380 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
8382 perf_iterate_sb(perf_event_switch_output,
8388 * IRQ throttle logging
8391 static void perf_log_throttle(struct perf_event *event, int enable)
8393 struct perf_output_handle handle;
8394 struct perf_sample_data sample;
8398 struct perf_event_header header;
8402 } throttle_event = {
8404 .type = PERF_RECORD_THROTTLE,
8406 .size = sizeof(throttle_event),
8408 .time = perf_event_clock(event),
8409 .id = primary_event_id(event),
8410 .stream_id = event->id,
8414 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
8416 perf_event_header__init_id(&throttle_event.header, &sample, event);
8418 ret = perf_output_begin(&handle, event,
8419 throttle_event.header.size);
8423 perf_output_put(&handle, throttle_event);
8424 perf_event__output_id_sample(event, &handle, &sample);
8425 perf_output_end(&handle);
8429 * ksymbol register/unregister tracking
8432 struct perf_ksymbol_event {
8436 struct perf_event_header header;
8444 static int perf_event_ksymbol_match(struct perf_event *event)
8446 return event->attr.ksymbol;
8449 static void perf_event_ksymbol_output(struct perf_event *event, void *data)
8451 struct perf_ksymbol_event *ksymbol_event = data;
8452 struct perf_output_handle handle;
8453 struct perf_sample_data sample;
8456 if (!perf_event_ksymbol_match(event))
8459 perf_event_header__init_id(&ksymbol_event->event_id.header,
8461 ret = perf_output_begin(&handle, event,
8462 ksymbol_event->event_id.header.size);
8466 perf_output_put(&handle, ksymbol_event->event_id);
8467 __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
8468 perf_event__output_id_sample(event, &handle, &sample);
8470 perf_output_end(&handle);
8473 void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
8476 struct perf_ksymbol_event ksymbol_event;
8477 char name[KSYM_NAME_LEN];
8481 if (!atomic_read(&nr_ksymbol_events))
8484 if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
8485 ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
8488 strlcpy(name, sym, KSYM_NAME_LEN);
8489 name_len = strlen(name) + 1;
8490 while (!IS_ALIGNED(name_len, sizeof(u64)))
8491 name[name_len++] = '\0';
8492 BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
8495 flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
8497 ksymbol_event = (struct perf_ksymbol_event){
8499 .name_len = name_len,
8502 .type = PERF_RECORD_KSYMBOL,
8503 .size = sizeof(ksymbol_event.event_id) +
8508 .ksym_type = ksym_type,
8513 perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
8516 WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
8520 * bpf program load/unload tracking
8523 struct perf_bpf_event {
8524 struct bpf_prog *prog;
8526 struct perf_event_header header;
8530 u8 tag[BPF_TAG_SIZE];
8534 static int perf_event_bpf_match(struct perf_event *event)
8536 return event->attr.bpf_event;
8539 static void perf_event_bpf_output(struct perf_event *event, void *data)
8541 struct perf_bpf_event *bpf_event = data;
8542 struct perf_output_handle handle;
8543 struct perf_sample_data sample;
8546 if (!perf_event_bpf_match(event))
8549 perf_event_header__init_id(&bpf_event->event_id.header,
8551 ret = perf_output_begin(&handle, event,
8552 bpf_event->event_id.header.size);
8556 perf_output_put(&handle, bpf_event->event_id);
8557 perf_event__output_id_sample(event, &handle, &sample);
8559 perf_output_end(&handle);
8562 static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
8563 enum perf_bpf_event_type type)
8565 bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
8568 if (prog->aux->func_cnt == 0) {
8569 perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
8570 (u64)(unsigned long)prog->bpf_func,
8571 prog->jited_len, unregister,
8572 prog->aux->ksym.name);
8574 for (i = 0; i < prog->aux->func_cnt; i++) {
8575 struct bpf_prog *subprog = prog->aux->func[i];
8578 PERF_RECORD_KSYMBOL_TYPE_BPF,
8579 (u64)(unsigned long)subprog->bpf_func,
8580 subprog->jited_len, unregister,
8581 prog->aux->ksym.name);
8586 void perf_event_bpf_event(struct bpf_prog *prog,
8587 enum perf_bpf_event_type type,
8590 struct perf_bpf_event bpf_event;
8592 if (type <= PERF_BPF_EVENT_UNKNOWN ||
8593 type >= PERF_BPF_EVENT_MAX)
8597 case PERF_BPF_EVENT_PROG_LOAD:
8598 case PERF_BPF_EVENT_PROG_UNLOAD:
8599 if (atomic_read(&nr_ksymbol_events))
8600 perf_event_bpf_emit_ksymbols(prog, type);
8606 if (!atomic_read(&nr_bpf_events))
8609 bpf_event = (struct perf_bpf_event){
8613 .type = PERF_RECORD_BPF_EVENT,
8614 .size = sizeof(bpf_event.event_id),
8618 .id = prog->aux->id,
8622 BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
8624 memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
8625 perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
8628 void perf_event_itrace_started(struct perf_event *event)
8630 event->attach_state |= PERF_ATTACH_ITRACE;
8633 static void perf_log_itrace_start(struct perf_event *event)
8635 struct perf_output_handle handle;
8636 struct perf_sample_data sample;
8637 struct perf_aux_event {
8638 struct perf_event_header header;
8645 event = event->parent;
8647 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
8648 event->attach_state & PERF_ATTACH_ITRACE)
8651 rec.header.type = PERF_RECORD_ITRACE_START;
8652 rec.header.misc = 0;
8653 rec.header.size = sizeof(rec);
8654 rec.pid = perf_event_pid(event, current);
8655 rec.tid = perf_event_tid(event, current);
8657 perf_event_header__init_id(&rec.header, &sample, event);
8658 ret = perf_output_begin(&handle, event, rec.header.size);
8663 perf_output_put(&handle, rec);
8664 perf_event__output_id_sample(event, &handle, &sample);
8666 perf_output_end(&handle);
8670 __perf_event_account_interrupt(struct perf_event *event, int throttle)
8672 struct hw_perf_event *hwc = &event->hw;
8676 seq = __this_cpu_read(perf_throttled_seq);
8677 if (seq != hwc->interrupts_seq) {
8678 hwc->interrupts_seq = seq;
8679 hwc->interrupts = 1;
8682 if (unlikely(throttle
8683 && hwc->interrupts >= max_samples_per_tick)) {
8684 __this_cpu_inc(perf_throttled_count);
8685 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
8686 hwc->interrupts = MAX_INTERRUPTS;
8687 perf_log_throttle(event, 0);
8692 if (event->attr.freq) {
8693 u64 now = perf_clock();
8694 s64 delta = now - hwc->freq_time_stamp;
8696 hwc->freq_time_stamp = now;
8698 if (delta > 0 && delta < 2*TICK_NSEC)
8699 perf_adjust_period(event, delta, hwc->last_period, true);
8705 int perf_event_account_interrupt(struct perf_event *event)
8707 return __perf_event_account_interrupt(event, 1);
8711 * Generic event overflow handling, sampling.
8714 static int __perf_event_overflow(struct perf_event *event,
8715 int throttle, struct perf_sample_data *data,
8716 struct pt_regs *regs)
8718 int events = atomic_read(&event->event_limit);
8722 * Non-sampling counters might still use the PMI to fold short
8723 * hardware counters, ignore those.
8725 if (unlikely(!is_sampling_event(event)))
8728 ret = __perf_event_account_interrupt(event, throttle);
8731 * XXX event_limit might not quite work as expected on inherited
8735 event->pending_kill = POLL_IN;
8736 if (events && atomic_dec_and_test(&event->event_limit)) {
8738 event->pending_kill = POLL_HUP;
8740 perf_event_disable_inatomic(event);
8743 READ_ONCE(event->overflow_handler)(event, data, regs);
8745 if (*perf_event_fasync(event) && event->pending_kill) {
8746 event->pending_wakeup = 1;
8747 irq_work_queue(&event->pending);
8753 int perf_event_overflow(struct perf_event *event,
8754 struct perf_sample_data *data,
8755 struct pt_regs *regs)
8757 return __perf_event_overflow(event, 1, data, regs);
8761 * Generic software event infrastructure
8764 struct swevent_htable {
8765 struct swevent_hlist *swevent_hlist;
8766 struct mutex hlist_mutex;
8769 /* Recursion avoidance in each contexts */
8770 int recursion[PERF_NR_CONTEXTS];
8773 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
8776 * We directly increment event->count and keep a second value in
8777 * event->hw.period_left to count intervals. This period event
8778 * is kept in the range [-sample_period, 0] so that we can use the
8782 u64 perf_swevent_set_period(struct perf_event *event)
8784 struct hw_perf_event *hwc = &event->hw;
8785 u64 period = hwc->last_period;
8789 hwc->last_period = hwc->sample_period;
8792 old = val = local64_read(&hwc->period_left);
8796 nr = div64_u64(period + val, period);
8797 offset = nr * period;
8799 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
8805 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
8806 struct perf_sample_data *data,
8807 struct pt_regs *regs)
8809 struct hw_perf_event *hwc = &event->hw;
8813 overflow = perf_swevent_set_period(event);
8815 if (hwc->interrupts == MAX_INTERRUPTS)
8818 for (; overflow; overflow--) {
8819 if (__perf_event_overflow(event, throttle,
8822 * We inhibit the overflow from happening when
8823 * hwc->interrupts == MAX_INTERRUPTS.
8831 static void perf_swevent_event(struct perf_event *event, u64 nr,
8832 struct perf_sample_data *data,
8833 struct pt_regs *regs)
8835 struct hw_perf_event *hwc = &event->hw;
8837 local64_add(nr, &event->count);
8842 if (!is_sampling_event(event))
8845 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
8847 return perf_swevent_overflow(event, 1, data, regs);
8849 data->period = event->hw.last_period;
8851 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
8852 return perf_swevent_overflow(event, 1, data, regs);
8854 if (local64_add_negative(nr, &hwc->period_left))
8857 perf_swevent_overflow(event, 0, data, regs);
8860 static int perf_exclude_event(struct perf_event *event,
8861 struct pt_regs *regs)
8863 if (event->hw.state & PERF_HES_STOPPED)
8867 if (event->attr.exclude_user && user_mode(regs))
8870 if (event->attr.exclude_kernel && !user_mode(regs))
8877 static int perf_swevent_match(struct perf_event *event,
8878 enum perf_type_id type,
8880 struct perf_sample_data *data,
8881 struct pt_regs *regs)
8883 if (event->attr.type != type)
8886 if (event->attr.config != event_id)
8889 if (perf_exclude_event(event, regs))
8895 static inline u64 swevent_hash(u64 type, u32 event_id)
8897 u64 val = event_id | (type << 32);
8899 return hash_64(val, SWEVENT_HLIST_BITS);
8902 static inline struct hlist_head *
8903 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
8905 u64 hash = swevent_hash(type, event_id);
8907 return &hlist->heads[hash];
8910 /* For the read side: events when they trigger */
8911 static inline struct hlist_head *
8912 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8914 struct swevent_hlist *hlist;
8916 hlist = rcu_dereference(swhash->swevent_hlist);
8920 return __find_swevent_head(hlist, type, event_id);
8923 /* For the event head insertion and removal in the hlist */
8924 static inline struct hlist_head *
8925 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8927 struct swevent_hlist *hlist;
8928 u32 event_id = event->attr.config;
8929 u64 type = event->attr.type;
8932 * Event scheduling is always serialized against hlist allocation
8933 * and release. Which makes the protected version suitable here.
8934 * The context lock guarantees that.
8936 hlist = rcu_dereference_protected(swhash->swevent_hlist,
8937 lockdep_is_held(&event->ctx->lock));
8941 return __find_swevent_head(hlist, type, event_id);
8944 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8946 struct perf_sample_data *data,
8947 struct pt_regs *regs)
8949 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8950 struct perf_event *event;
8951 struct hlist_head *head;
8954 head = find_swevent_head_rcu(swhash, type, event_id);
8958 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8959 if (perf_swevent_match(event, type, event_id, data, regs))
8960 perf_swevent_event(event, nr, data, regs);
8966 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8968 int perf_swevent_get_recursion_context(void)
8970 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8972 return get_recursion_context(swhash->recursion);
8974 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8976 void perf_swevent_put_recursion_context(int rctx)
8978 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8980 put_recursion_context(swhash->recursion, rctx);
8983 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8985 struct perf_sample_data data;
8987 if (WARN_ON_ONCE(!regs))
8990 perf_sample_data_init(&data, addr, 0);
8991 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8994 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8998 preempt_disable_notrace();
8999 rctx = perf_swevent_get_recursion_context();
9000 if (unlikely(rctx < 0))
9003 ___perf_sw_event(event_id, nr, regs, addr);
9005 perf_swevent_put_recursion_context(rctx);
9007 preempt_enable_notrace();
9010 static void perf_swevent_read(struct perf_event *event)
9014 static int perf_swevent_add(struct perf_event *event, int flags)
9016 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9017 struct hw_perf_event *hwc = &event->hw;
9018 struct hlist_head *head;
9020 if (is_sampling_event(event)) {
9021 hwc->last_period = hwc->sample_period;
9022 perf_swevent_set_period(event);
9025 hwc->state = !(flags & PERF_EF_START);
9027 head = find_swevent_head(swhash, event);
9028 if (WARN_ON_ONCE(!head))
9031 hlist_add_head_rcu(&event->hlist_entry, head);
9032 perf_event_update_userpage(event);
9037 static void perf_swevent_del(struct perf_event *event, int flags)
9039 hlist_del_rcu(&event->hlist_entry);
9042 static void perf_swevent_start(struct perf_event *event, int flags)
9044 event->hw.state = 0;
9047 static void perf_swevent_stop(struct perf_event *event, int flags)
9049 event->hw.state = PERF_HES_STOPPED;
9052 /* Deref the hlist from the update side */
9053 static inline struct swevent_hlist *
9054 swevent_hlist_deref(struct swevent_htable *swhash)
9056 return rcu_dereference_protected(swhash->swevent_hlist,
9057 lockdep_is_held(&swhash->hlist_mutex));
9060 static void swevent_hlist_release(struct swevent_htable *swhash)
9062 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
9067 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
9068 kfree_rcu(hlist, rcu_head);
9071 static void swevent_hlist_put_cpu(int cpu)
9073 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9075 mutex_lock(&swhash->hlist_mutex);
9077 if (!--swhash->hlist_refcount)
9078 swevent_hlist_release(swhash);
9080 mutex_unlock(&swhash->hlist_mutex);
9083 static void swevent_hlist_put(void)
9087 for_each_possible_cpu(cpu)
9088 swevent_hlist_put_cpu(cpu);
9091 static int swevent_hlist_get_cpu(int cpu)
9093 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9096 mutex_lock(&swhash->hlist_mutex);
9097 if (!swevent_hlist_deref(swhash) &&
9098 cpumask_test_cpu(cpu, perf_online_mask)) {
9099 struct swevent_hlist *hlist;
9101 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
9106 rcu_assign_pointer(swhash->swevent_hlist, hlist);
9108 swhash->hlist_refcount++;
9110 mutex_unlock(&swhash->hlist_mutex);
9115 static int swevent_hlist_get(void)
9117 int err, cpu, failed_cpu;
9119 mutex_lock(&pmus_lock);
9120 for_each_possible_cpu(cpu) {
9121 err = swevent_hlist_get_cpu(cpu);
9127 mutex_unlock(&pmus_lock);
9130 for_each_possible_cpu(cpu) {
9131 if (cpu == failed_cpu)
9133 swevent_hlist_put_cpu(cpu);
9135 mutex_unlock(&pmus_lock);
9139 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
9141 static void sw_perf_event_destroy(struct perf_event *event)
9143 u64 event_id = event->attr.config;
9145 WARN_ON(event->parent);
9147 static_key_slow_dec(&perf_swevent_enabled[event_id]);
9148 swevent_hlist_put();
9151 static int perf_swevent_init(struct perf_event *event)
9153 u64 event_id = event->attr.config;
9155 if (event->attr.type != PERF_TYPE_SOFTWARE)
9159 * no branch sampling for software events
9161 if (has_branch_stack(event))
9165 case PERF_COUNT_SW_CPU_CLOCK:
9166 case PERF_COUNT_SW_TASK_CLOCK:
9173 if (event_id >= PERF_COUNT_SW_MAX)
9176 if (!event->parent) {
9179 err = swevent_hlist_get();
9183 static_key_slow_inc(&perf_swevent_enabled[event_id]);
9184 event->destroy = sw_perf_event_destroy;
9190 static struct pmu perf_swevent = {
9191 .task_ctx_nr = perf_sw_context,
9193 .capabilities = PERF_PMU_CAP_NO_NMI,
9195 .event_init = perf_swevent_init,
9196 .add = perf_swevent_add,
9197 .del = perf_swevent_del,
9198 .start = perf_swevent_start,
9199 .stop = perf_swevent_stop,
9200 .read = perf_swevent_read,
9203 #ifdef CONFIG_EVENT_TRACING
9205 static int perf_tp_filter_match(struct perf_event *event,
9206 struct perf_sample_data *data)
9208 void *record = data->raw->frag.data;
9210 /* only top level events have filters set */
9212 event = event->parent;
9214 if (likely(!event->filter) || filter_match_preds(event->filter, record))
9219 static int perf_tp_event_match(struct perf_event *event,
9220 struct perf_sample_data *data,
9221 struct pt_regs *regs)
9223 if (event->hw.state & PERF_HES_STOPPED)
9226 * If exclude_kernel, only trace user-space tracepoints (uprobes)
9228 if (event->attr.exclude_kernel && !user_mode(regs))
9231 if (!perf_tp_filter_match(event, data))
9237 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
9238 struct trace_event_call *call, u64 count,
9239 struct pt_regs *regs, struct hlist_head *head,
9240 struct task_struct *task)
9242 if (bpf_prog_array_valid(call)) {
9243 *(struct pt_regs **)raw_data = regs;
9244 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
9245 perf_swevent_put_recursion_context(rctx);
9249 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
9252 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
9254 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
9255 struct pt_regs *regs, struct hlist_head *head, int rctx,
9256 struct task_struct *task)
9258 struct perf_sample_data data;
9259 struct perf_event *event;
9261 struct perf_raw_record raw = {
9268 perf_sample_data_init(&data, 0, 0);
9271 perf_trace_buf_update(record, event_type);
9273 hlist_for_each_entry_rcu(event, head, hlist_entry) {
9274 if (perf_tp_event_match(event, &data, regs))
9275 perf_swevent_event(event, count, &data, regs);
9279 * If we got specified a target task, also iterate its context and
9280 * deliver this event there too.
9282 if (task && task != current) {
9283 struct perf_event_context *ctx;
9284 struct trace_entry *entry = record;
9287 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
9291 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
9292 if (event->cpu != smp_processor_id())
9294 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9296 if (event->attr.config != entry->type)
9298 if (perf_tp_event_match(event, &data, regs))
9299 perf_swevent_event(event, count, &data, regs);
9305 perf_swevent_put_recursion_context(rctx);
9307 EXPORT_SYMBOL_GPL(perf_tp_event);
9309 static void tp_perf_event_destroy(struct perf_event *event)
9311 perf_trace_destroy(event);
9314 static int perf_tp_event_init(struct perf_event *event)
9318 if (event->attr.type != PERF_TYPE_TRACEPOINT)
9322 * no branch sampling for tracepoint events
9324 if (has_branch_stack(event))
9327 err = perf_trace_init(event);
9331 event->destroy = tp_perf_event_destroy;
9336 static struct pmu perf_tracepoint = {
9337 .task_ctx_nr = perf_sw_context,
9339 .event_init = perf_tp_event_init,
9340 .add = perf_trace_add,
9341 .del = perf_trace_del,
9342 .start = perf_swevent_start,
9343 .stop = perf_swevent_stop,
9344 .read = perf_swevent_read,
9347 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
9349 * Flags in config, used by dynamic PMU kprobe and uprobe
9350 * The flags should match following PMU_FORMAT_ATTR().
9352 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
9353 * if not set, create kprobe/uprobe
9355 * The following values specify a reference counter (or semaphore in the
9356 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
9357 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
9359 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
9360 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
9362 enum perf_probe_config {
9363 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
9364 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
9365 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
9368 PMU_FORMAT_ATTR(retprobe, "config:0");
9371 #ifdef CONFIG_KPROBE_EVENTS
9372 static struct attribute *kprobe_attrs[] = {
9373 &format_attr_retprobe.attr,
9377 static struct attribute_group kprobe_format_group = {
9379 .attrs = kprobe_attrs,
9382 static const struct attribute_group *kprobe_attr_groups[] = {
9383 &kprobe_format_group,
9387 static int perf_kprobe_event_init(struct perf_event *event);
9388 static struct pmu perf_kprobe = {
9389 .task_ctx_nr = perf_sw_context,
9390 .event_init = perf_kprobe_event_init,
9391 .add = perf_trace_add,
9392 .del = perf_trace_del,
9393 .start = perf_swevent_start,
9394 .stop = perf_swevent_stop,
9395 .read = perf_swevent_read,
9396 .attr_groups = kprobe_attr_groups,
9399 static int perf_kprobe_event_init(struct perf_event *event)
9404 if (event->attr.type != perf_kprobe.type)
9407 if (!capable(CAP_SYS_ADMIN))
9411 * no branch sampling for probe events
9413 if (has_branch_stack(event))
9416 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9417 err = perf_kprobe_init(event, is_retprobe);
9421 event->destroy = perf_kprobe_destroy;
9425 #endif /* CONFIG_KPROBE_EVENTS */
9427 #ifdef CONFIG_UPROBE_EVENTS
9428 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
9430 static struct attribute *uprobe_attrs[] = {
9431 &format_attr_retprobe.attr,
9432 &format_attr_ref_ctr_offset.attr,
9436 static struct attribute_group uprobe_format_group = {
9438 .attrs = uprobe_attrs,
9441 static const struct attribute_group *uprobe_attr_groups[] = {
9442 &uprobe_format_group,
9446 static int perf_uprobe_event_init(struct perf_event *event);
9447 static struct pmu perf_uprobe = {
9448 .task_ctx_nr = perf_sw_context,
9449 .event_init = perf_uprobe_event_init,
9450 .add = perf_trace_add,
9451 .del = perf_trace_del,
9452 .start = perf_swevent_start,
9453 .stop = perf_swevent_stop,
9454 .read = perf_swevent_read,
9455 .attr_groups = uprobe_attr_groups,
9458 static int perf_uprobe_event_init(struct perf_event *event)
9461 unsigned long ref_ctr_offset;
9464 if (event->attr.type != perf_uprobe.type)
9467 if (!capable(CAP_SYS_ADMIN))
9471 * no branch sampling for probe events
9473 if (has_branch_stack(event))
9476 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9477 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
9478 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
9482 event->destroy = perf_uprobe_destroy;
9486 #endif /* CONFIG_UPROBE_EVENTS */
9488 static inline void perf_tp_register(void)
9490 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
9491 #ifdef CONFIG_KPROBE_EVENTS
9492 perf_pmu_register(&perf_kprobe, "kprobe", -1);
9494 #ifdef CONFIG_UPROBE_EVENTS
9495 perf_pmu_register(&perf_uprobe, "uprobe", -1);
9499 static void perf_event_free_filter(struct perf_event *event)
9501 ftrace_profile_free_filter(event);
9504 #ifdef CONFIG_BPF_SYSCALL
9505 static void bpf_overflow_handler(struct perf_event *event,
9506 struct perf_sample_data *data,
9507 struct pt_regs *regs)
9509 struct bpf_perf_event_data_kern ctx = {
9515 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
9516 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
9519 ret = BPF_PROG_RUN(event->prog, &ctx);
9522 __this_cpu_dec(bpf_prog_active);
9526 event->orig_overflow_handler(event, data, regs);
9529 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9531 struct bpf_prog *prog;
9533 if (event->overflow_handler_context)
9534 /* hw breakpoint or kernel counter */
9540 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
9542 return PTR_ERR(prog);
9545 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
9546 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
9550 static void perf_event_free_bpf_handler(struct perf_event *event)
9552 struct bpf_prog *prog = event->prog;
9557 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
9562 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9566 static void perf_event_free_bpf_handler(struct perf_event *event)
9572 * returns true if the event is a tracepoint, or a kprobe/upprobe created
9573 * with perf_event_open()
9575 static inline bool perf_event_is_tracing(struct perf_event *event)
9577 if (event->pmu == &perf_tracepoint)
9579 #ifdef CONFIG_KPROBE_EVENTS
9580 if (event->pmu == &perf_kprobe)
9583 #ifdef CONFIG_UPROBE_EVENTS
9584 if (event->pmu == &perf_uprobe)
9590 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9592 bool is_kprobe, is_tracepoint, is_syscall_tp;
9593 struct bpf_prog *prog;
9596 if (!perf_event_is_tracing(event))
9597 return perf_event_set_bpf_handler(event, prog_fd);
9599 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
9600 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
9601 is_syscall_tp = is_syscall_trace_event(event->tp_event);
9602 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
9603 /* bpf programs can only be attached to u/kprobe or tracepoint */
9606 prog = bpf_prog_get(prog_fd);
9608 return PTR_ERR(prog);
9610 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
9611 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
9612 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
9613 /* valid fd, but invalid bpf program type */
9618 /* Kprobe override only works for kprobes, not uprobes. */
9619 if (prog->kprobe_override &&
9620 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
9625 if (is_tracepoint || is_syscall_tp) {
9626 int off = trace_event_get_offsets(event->tp_event);
9628 if (prog->aux->max_ctx_offset > off) {
9634 ret = perf_event_attach_bpf_prog(event, prog);
9640 static void perf_event_free_bpf_prog(struct perf_event *event)
9642 if (!perf_event_is_tracing(event)) {
9643 perf_event_free_bpf_handler(event);
9646 perf_event_detach_bpf_prog(event);
9651 static inline void perf_tp_register(void)
9655 static void perf_event_free_filter(struct perf_event *event)
9659 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9664 static void perf_event_free_bpf_prog(struct perf_event *event)
9667 #endif /* CONFIG_EVENT_TRACING */
9669 #ifdef CONFIG_HAVE_HW_BREAKPOINT
9670 void perf_bp_event(struct perf_event *bp, void *data)
9672 struct perf_sample_data sample;
9673 struct pt_regs *regs = data;
9675 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
9677 if (!bp->hw.state && !perf_exclude_event(bp, regs))
9678 perf_swevent_event(bp, 1, &sample, regs);
9683 * Allocate a new address filter
9685 static struct perf_addr_filter *
9686 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
9688 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
9689 struct perf_addr_filter *filter;
9691 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
9695 INIT_LIST_HEAD(&filter->entry);
9696 list_add_tail(&filter->entry, filters);
9701 static void free_filters_list(struct list_head *filters)
9703 struct perf_addr_filter *filter, *iter;
9705 list_for_each_entry_safe(filter, iter, filters, entry) {
9706 path_put(&filter->path);
9707 list_del(&filter->entry);
9713 * Free existing address filters and optionally install new ones
9715 static void perf_addr_filters_splice(struct perf_event *event,
9716 struct list_head *head)
9718 unsigned long flags;
9721 if (!has_addr_filter(event))
9724 /* don't bother with children, they don't have their own filters */
9728 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
9730 list_splice_init(&event->addr_filters.list, &list);
9732 list_splice(head, &event->addr_filters.list);
9734 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
9736 free_filters_list(&list);
9740 * Scan through mm's vmas and see if one of them matches the
9741 * @filter; if so, adjust filter's address range.
9742 * Called with mm::mmap_sem down for reading.
9744 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
9745 struct mm_struct *mm,
9746 struct perf_addr_filter_range *fr)
9748 struct vm_area_struct *vma;
9750 for (vma = mm->mmap; vma; vma = vma->vm_next) {
9754 if (perf_addr_filter_vma_adjust(filter, vma, fr))
9760 * Update event's address range filters based on the
9761 * task's existing mappings, if any.
9763 static void perf_event_addr_filters_apply(struct perf_event *event)
9765 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
9766 struct task_struct *task = READ_ONCE(event->ctx->task);
9767 struct perf_addr_filter *filter;
9768 struct mm_struct *mm = NULL;
9769 unsigned int count = 0;
9770 unsigned long flags;
9773 * We may observe TASK_TOMBSTONE, which means that the event tear-down
9774 * will stop on the parent's child_mutex that our caller is also holding
9776 if (task == TASK_TOMBSTONE)
9779 if (ifh->nr_file_filters) {
9780 mm = get_task_mm(event->ctx->task);
9784 down_read(&mm->mmap_sem);
9787 raw_spin_lock_irqsave(&ifh->lock, flags);
9788 list_for_each_entry(filter, &ifh->list, entry) {
9789 if (filter->path.dentry) {
9791 * Adjust base offset if the filter is associated to a
9792 * binary that needs to be mapped:
9794 event->addr_filter_ranges[count].start = 0;
9795 event->addr_filter_ranges[count].size = 0;
9797 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
9799 event->addr_filter_ranges[count].start = filter->offset;
9800 event->addr_filter_ranges[count].size = filter->size;
9806 event->addr_filters_gen++;
9807 raw_spin_unlock_irqrestore(&ifh->lock, flags);
9809 if (ifh->nr_file_filters) {
9810 up_read(&mm->mmap_sem);
9816 perf_event_stop(event, 1);
9820 * Address range filtering: limiting the data to certain
9821 * instruction address ranges. Filters are ioctl()ed to us from
9822 * userspace as ascii strings.
9824 * Filter string format:
9827 * where ACTION is one of the
9828 * * "filter": limit the trace to this region
9829 * * "start": start tracing from this address
9830 * * "stop": stop tracing at this address/region;
9832 * * for kernel addresses: <start address>[/<size>]
9833 * * for object files: <start address>[/<size>]@</path/to/object/file>
9835 * if <size> is not specified or is zero, the range is treated as a single
9836 * address; not valid for ACTION=="filter".
9850 IF_STATE_ACTION = 0,
9855 static const match_table_t if_tokens = {
9856 { IF_ACT_FILTER, "filter" },
9857 { IF_ACT_START, "start" },
9858 { IF_ACT_STOP, "stop" },
9859 { IF_SRC_FILE, "%u/%u@%s" },
9860 { IF_SRC_KERNEL, "%u/%u" },
9861 { IF_SRC_FILEADDR, "%u@%s" },
9862 { IF_SRC_KERNELADDR, "%u" },
9863 { IF_ACT_NONE, NULL },
9867 * Address filter string parser
9870 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
9871 struct list_head *filters)
9873 struct perf_addr_filter *filter = NULL;
9874 char *start, *orig, *filename = NULL;
9875 substring_t args[MAX_OPT_ARGS];
9876 int state = IF_STATE_ACTION, token;
9877 unsigned int kernel = 0;
9880 orig = fstr = kstrdup(fstr, GFP_KERNEL);
9884 while ((start = strsep(&fstr, " ,\n")) != NULL) {
9885 static const enum perf_addr_filter_action_t actions[] = {
9886 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
9887 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
9888 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
9895 /* filter definition begins */
9896 if (state == IF_STATE_ACTION) {
9897 filter = perf_addr_filter_new(event, filters);
9902 token = match_token(start, if_tokens, args);
9907 if (state != IF_STATE_ACTION)
9910 filter->action = actions[token];
9911 state = IF_STATE_SOURCE;
9914 case IF_SRC_KERNELADDR:
9919 case IF_SRC_FILEADDR:
9921 if (state != IF_STATE_SOURCE)
9925 ret = kstrtoul(args[0].from, 0, &filter->offset);
9929 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
9931 ret = kstrtoul(args[1].from, 0, &filter->size);
9936 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9937 int fpos = token == IF_SRC_FILE ? 2 : 1;
9939 filename = match_strdup(&args[fpos]);
9946 state = IF_STATE_END;
9954 * Filter definition is fully parsed, validate and install it.
9955 * Make sure that it doesn't contradict itself or the event's
9958 if (state == IF_STATE_END) {
9960 if (kernel && event->attr.exclude_kernel)
9964 * ACTION "filter" must have a non-zero length region
9967 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9976 * For now, we only support file-based filters
9977 * in per-task events; doing so for CPU-wide
9978 * events requires additional context switching
9979 * trickery, since same object code will be
9980 * mapped at different virtual addresses in
9981 * different processes.
9984 if (!event->ctx->task)
9985 goto fail_free_name;
9987 /* look up the path and grab its inode */
9988 ret = kern_path(filename, LOOKUP_FOLLOW,
9991 goto fail_free_name;
9997 if (!filter->path.dentry ||
9998 !S_ISREG(d_inode(filter->path.dentry)
10002 event->addr_filters.nr_file_filters++;
10005 /* ready to consume more filters */
10006 state = IF_STATE_ACTION;
10011 if (state != IF_STATE_ACTION)
10021 free_filters_list(filters);
10028 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
10030 LIST_HEAD(filters);
10034 * Since this is called in perf_ioctl() path, we're already holding
10037 lockdep_assert_held(&event->ctx->mutex);
10039 if (WARN_ON_ONCE(event->parent))
10042 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
10044 goto fail_clear_files;
10046 ret = event->pmu->addr_filters_validate(&filters);
10048 goto fail_free_filters;
10050 /* remove existing filters, if any */
10051 perf_addr_filters_splice(event, &filters);
10053 /* install new filters */
10054 perf_event_for_each_child(event, perf_event_addr_filters_apply);
10059 free_filters_list(&filters);
10062 event->addr_filters.nr_file_filters = 0;
10067 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
10072 filter_str = strndup_user(arg, PAGE_SIZE);
10073 if (IS_ERR(filter_str))
10074 return PTR_ERR(filter_str);
10076 #ifdef CONFIG_EVENT_TRACING
10077 if (perf_event_is_tracing(event)) {
10078 struct perf_event_context *ctx = event->ctx;
10081 * Beware, here be dragons!!
10083 * the tracepoint muck will deadlock against ctx->mutex, but
10084 * the tracepoint stuff does not actually need it. So
10085 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
10086 * already have a reference on ctx.
10088 * This can result in event getting moved to a different ctx,
10089 * but that does not affect the tracepoint state.
10091 mutex_unlock(&ctx->mutex);
10092 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
10093 mutex_lock(&ctx->mutex);
10096 if (has_addr_filter(event))
10097 ret = perf_event_set_addr_filter(event, filter_str);
10104 * hrtimer based swevent callback
10107 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
10109 enum hrtimer_restart ret = HRTIMER_RESTART;
10110 struct perf_sample_data data;
10111 struct pt_regs *regs;
10112 struct perf_event *event;
10115 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
10117 if (event->state != PERF_EVENT_STATE_ACTIVE)
10118 return HRTIMER_NORESTART;
10120 event->pmu->read(event);
10122 perf_sample_data_init(&data, 0, event->hw.last_period);
10123 regs = get_irq_regs();
10125 if (regs && !perf_exclude_event(event, regs)) {
10126 if (!(event->attr.exclude_idle && is_idle_task(current)))
10127 if (__perf_event_overflow(event, 1, &data, regs))
10128 ret = HRTIMER_NORESTART;
10131 period = max_t(u64, 10000, event->hw.sample_period);
10132 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
10137 static void perf_swevent_start_hrtimer(struct perf_event *event)
10139 struct hw_perf_event *hwc = &event->hw;
10142 if (!is_sampling_event(event))
10145 period = local64_read(&hwc->period_left);
10150 local64_set(&hwc->period_left, 0);
10152 period = max_t(u64, 10000, hwc->sample_period);
10154 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
10155 HRTIMER_MODE_REL_PINNED_HARD);
10158 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
10160 struct hw_perf_event *hwc = &event->hw;
10162 if (is_sampling_event(event)) {
10163 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
10164 local64_set(&hwc->period_left, ktime_to_ns(remaining));
10166 hrtimer_cancel(&hwc->hrtimer);
10170 static void perf_swevent_init_hrtimer(struct perf_event *event)
10172 struct hw_perf_event *hwc = &event->hw;
10174 if (!is_sampling_event(event))
10177 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
10178 hwc->hrtimer.function = perf_swevent_hrtimer;
10181 * Since hrtimers have a fixed rate, we can do a static freq->period
10182 * mapping and avoid the whole period adjust feedback stuff.
10184 if (event->attr.freq) {
10185 long freq = event->attr.sample_freq;
10187 event->attr.sample_period = NSEC_PER_SEC / freq;
10188 hwc->sample_period = event->attr.sample_period;
10189 local64_set(&hwc->period_left, hwc->sample_period);
10190 hwc->last_period = hwc->sample_period;
10191 event->attr.freq = 0;
10196 * Software event: cpu wall time clock
10199 static void cpu_clock_event_update(struct perf_event *event)
10204 now = local_clock();
10205 prev = local64_xchg(&event->hw.prev_count, now);
10206 local64_add(now - prev, &event->count);
10209 static void cpu_clock_event_start(struct perf_event *event, int flags)
10211 local64_set(&event->hw.prev_count, local_clock());
10212 perf_swevent_start_hrtimer(event);
10215 static void cpu_clock_event_stop(struct perf_event *event, int flags)
10217 perf_swevent_cancel_hrtimer(event);
10218 cpu_clock_event_update(event);
10221 static int cpu_clock_event_add(struct perf_event *event, int flags)
10223 if (flags & PERF_EF_START)
10224 cpu_clock_event_start(event, flags);
10225 perf_event_update_userpage(event);
10230 static void cpu_clock_event_del(struct perf_event *event, int flags)
10232 cpu_clock_event_stop(event, flags);
10235 static void cpu_clock_event_read(struct perf_event *event)
10237 cpu_clock_event_update(event);
10240 static int cpu_clock_event_init(struct perf_event *event)
10242 if (event->attr.type != PERF_TYPE_SOFTWARE)
10245 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
10249 * no branch sampling for software events
10251 if (has_branch_stack(event))
10252 return -EOPNOTSUPP;
10254 perf_swevent_init_hrtimer(event);
10259 static struct pmu perf_cpu_clock = {
10260 .task_ctx_nr = perf_sw_context,
10262 .capabilities = PERF_PMU_CAP_NO_NMI,
10264 .event_init = cpu_clock_event_init,
10265 .add = cpu_clock_event_add,
10266 .del = cpu_clock_event_del,
10267 .start = cpu_clock_event_start,
10268 .stop = cpu_clock_event_stop,
10269 .read = cpu_clock_event_read,
10273 * Software event: task time clock
10276 static void task_clock_event_update(struct perf_event *event, u64 now)
10281 prev = local64_xchg(&event->hw.prev_count, now);
10282 delta = now - prev;
10283 local64_add(delta, &event->count);
10286 static void task_clock_event_start(struct perf_event *event, int flags)
10288 local64_set(&event->hw.prev_count, event->ctx->time);
10289 perf_swevent_start_hrtimer(event);
10292 static void task_clock_event_stop(struct perf_event *event, int flags)
10294 perf_swevent_cancel_hrtimer(event);
10295 task_clock_event_update(event, event->ctx->time);
10298 static int task_clock_event_add(struct perf_event *event, int flags)
10300 if (flags & PERF_EF_START)
10301 task_clock_event_start(event, flags);
10302 perf_event_update_userpage(event);
10307 static void task_clock_event_del(struct perf_event *event, int flags)
10309 task_clock_event_stop(event, PERF_EF_UPDATE);
10312 static void task_clock_event_read(struct perf_event *event)
10314 u64 now = perf_clock();
10315 u64 delta = now - event->ctx->timestamp;
10316 u64 time = event->ctx->time + delta;
10318 task_clock_event_update(event, time);
10321 static int task_clock_event_init(struct perf_event *event)
10323 if (event->attr.type != PERF_TYPE_SOFTWARE)
10326 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
10330 * no branch sampling for software events
10332 if (has_branch_stack(event))
10333 return -EOPNOTSUPP;
10335 perf_swevent_init_hrtimer(event);
10340 static struct pmu perf_task_clock = {
10341 .task_ctx_nr = perf_sw_context,
10343 .capabilities = PERF_PMU_CAP_NO_NMI,
10345 .event_init = task_clock_event_init,
10346 .add = task_clock_event_add,
10347 .del = task_clock_event_del,
10348 .start = task_clock_event_start,
10349 .stop = task_clock_event_stop,
10350 .read = task_clock_event_read,
10353 static void perf_pmu_nop_void(struct pmu *pmu)
10357 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
10361 static int perf_pmu_nop_int(struct pmu *pmu)
10366 static int perf_event_nop_int(struct perf_event *event, u64 value)
10371 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
10373 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
10375 __this_cpu_write(nop_txn_flags, flags);
10377 if (flags & ~PERF_PMU_TXN_ADD)
10380 perf_pmu_disable(pmu);
10383 static int perf_pmu_commit_txn(struct pmu *pmu)
10385 unsigned int flags = __this_cpu_read(nop_txn_flags);
10387 __this_cpu_write(nop_txn_flags, 0);
10389 if (flags & ~PERF_PMU_TXN_ADD)
10392 perf_pmu_enable(pmu);
10396 static void perf_pmu_cancel_txn(struct pmu *pmu)
10398 unsigned int flags = __this_cpu_read(nop_txn_flags);
10400 __this_cpu_write(nop_txn_flags, 0);
10402 if (flags & ~PERF_PMU_TXN_ADD)
10405 perf_pmu_enable(pmu);
10408 static int perf_event_idx_default(struct perf_event *event)
10414 * Ensures all contexts with the same task_ctx_nr have the same
10415 * pmu_cpu_context too.
10417 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
10424 list_for_each_entry(pmu, &pmus, entry) {
10425 if (pmu->task_ctx_nr == ctxn)
10426 return pmu->pmu_cpu_context;
10432 static void free_pmu_context(struct pmu *pmu)
10435 * Static contexts such as perf_sw_context have a global lifetime
10436 * and may be shared between different PMUs. Avoid freeing them
10437 * when a single PMU is going away.
10439 if (pmu->task_ctx_nr > perf_invalid_context)
10442 free_percpu(pmu->pmu_cpu_context);
10446 * Let userspace know that this PMU supports address range filtering:
10448 static ssize_t nr_addr_filters_show(struct device *dev,
10449 struct device_attribute *attr,
10452 struct pmu *pmu = dev_get_drvdata(dev);
10454 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
10456 DEVICE_ATTR_RO(nr_addr_filters);
10458 static struct idr pmu_idr;
10461 type_show(struct device *dev, struct device_attribute *attr, char *page)
10463 struct pmu *pmu = dev_get_drvdata(dev);
10465 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
10467 static DEVICE_ATTR_RO(type);
10470 perf_event_mux_interval_ms_show(struct device *dev,
10471 struct device_attribute *attr,
10474 struct pmu *pmu = dev_get_drvdata(dev);
10476 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
10479 static DEFINE_MUTEX(mux_interval_mutex);
10482 perf_event_mux_interval_ms_store(struct device *dev,
10483 struct device_attribute *attr,
10484 const char *buf, size_t count)
10486 struct pmu *pmu = dev_get_drvdata(dev);
10487 int timer, cpu, ret;
10489 ret = kstrtoint(buf, 0, &timer);
10496 /* same value, noting to do */
10497 if (timer == pmu->hrtimer_interval_ms)
10500 mutex_lock(&mux_interval_mutex);
10501 pmu->hrtimer_interval_ms = timer;
10503 /* update all cpuctx for this PMU */
10505 for_each_online_cpu(cpu) {
10506 struct perf_cpu_context *cpuctx;
10507 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10508 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
10510 cpu_function_call(cpu,
10511 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
10513 cpus_read_unlock();
10514 mutex_unlock(&mux_interval_mutex);
10518 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
10520 static struct attribute *pmu_dev_attrs[] = {
10521 &dev_attr_type.attr,
10522 &dev_attr_perf_event_mux_interval_ms.attr,
10525 ATTRIBUTE_GROUPS(pmu_dev);
10527 static int pmu_bus_running;
10528 static struct bus_type pmu_bus = {
10529 .name = "event_source",
10530 .dev_groups = pmu_dev_groups,
10533 static void pmu_dev_release(struct device *dev)
10538 static int pmu_dev_alloc(struct pmu *pmu)
10542 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
10546 pmu->dev->groups = pmu->attr_groups;
10547 device_initialize(pmu->dev);
10548 ret = dev_set_name(pmu->dev, "%s", pmu->name);
10552 dev_set_drvdata(pmu->dev, pmu);
10553 pmu->dev->bus = &pmu_bus;
10554 pmu->dev->release = pmu_dev_release;
10555 ret = device_add(pmu->dev);
10559 /* For PMUs with address filters, throw in an extra attribute: */
10560 if (pmu->nr_addr_filters)
10561 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
10566 if (pmu->attr_update)
10567 ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
10576 device_del(pmu->dev);
10579 put_device(pmu->dev);
10583 static struct lock_class_key cpuctx_mutex;
10584 static struct lock_class_key cpuctx_lock;
10586 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
10588 int cpu, ret, max = PERF_TYPE_MAX;
10590 mutex_lock(&pmus_lock);
10592 pmu->pmu_disable_count = alloc_percpu(int);
10593 if (!pmu->pmu_disable_count)
10601 if (type != PERF_TYPE_SOFTWARE) {
10605 ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
10609 WARN_ON(type >= 0 && ret != type);
10615 if (pmu_bus_running) {
10616 ret = pmu_dev_alloc(pmu);
10622 if (pmu->task_ctx_nr == perf_hw_context) {
10623 static int hw_context_taken = 0;
10626 * Other than systems with heterogeneous CPUs, it never makes
10627 * sense for two PMUs to share perf_hw_context. PMUs which are
10628 * uncore must use perf_invalid_context.
10630 if (WARN_ON_ONCE(hw_context_taken &&
10631 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
10632 pmu->task_ctx_nr = perf_invalid_context;
10634 hw_context_taken = 1;
10637 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
10638 if (pmu->pmu_cpu_context)
10639 goto got_cpu_context;
10642 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
10643 if (!pmu->pmu_cpu_context)
10646 for_each_possible_cpu(cpu) {
10647 struct perf_cpu_context *cpuctx;
10649 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10650 __perf_event_init_context(&cpuctx->ctx);
10651 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
10652 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
10653 cpuctx->ctx.pmu = pmu;
10654 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
10656 __perf_mux_hrtimer_init(cpuctx, cpu);
10658 cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default);
10659 cpuctx->heap = cpuctx->heap_default;
10663 if (!pmu->start_txn) {
10664 if (pmu->pmu_enable) {
10666 * If we have pmu_enable/pmu_disable calls, install
10667 * transaction stubs that use that to try and batch
10668 * hardware accesses.
10670 pmu->start_txn = perf_pmu_start_txn;
10671 pmu->commit_txn = perf_pmu_commit_txn;
10672 pmu->cancel_txn = perf_pmu_cancel_txn;
10674 pmu->start_txn = perf_pmu_nop_txn;
10675 pmu->commit_txn = perf_pmu_nop_int;
10676 pmu->cancel_txn = perf_pmu_nop_void;
10680 if (!pmu->pmu_enable) {
10681 pmu->pmu_enable = perf_pmu_nop_void;
10682 pmu->pmu_disable = perf_pmu_nop_void;
10685 if (!pmu->check_period)
10686 pmu->check_period = perf_event_nop_int;
10688 if (!pmu->event_idx)
10689 pmu->event_idx = perf_event_idx_default;
10692 * Ensure the TYPE_SOFTWARE PMUs are at the head of the list,
10693 * since these cannot be in the IDR. This way the linear search
10694 * is fast, provided a valid software event is provided.
10696 if (type == PERF_TYPE_SOFTWARE || !name)
10697 list_add_rcu(&pmu->entry, &pmus);
10699 list_add_tail_rcu(&pmu->entry, &pmus);
10701 atomic_set(&pmu->exclusive_cnt, 0);
10704 mutex_unlock(&pmus_lock);
10709 device_del(pmu->dev);
10710 put_device(pmu->dev);
10713 if (pmu->type != PERF_TYPE_SOFTWARE)
10714 idr_remove(&pmu_idr, pmu->type);
10717 free_percpu(pmu->pmu_disable_count);
10720 EXPORT_SYMBOL_GPL(perf_pmu_register);
10722 void perf_pmu_unregister(struct pmu *pmu)
10724 mutex_lock(&pmus_lock);
10725 list_del_rcu(&pmu->entry);
10728 * We dereference the pmu list under both SRCU and regular RCU, so
10729 * synchronize against both of those.
10731 synchronize_srcu(&pmus_srcu);
10734 free_percpu(pmu->pmu_disable_count);
10735 if (pmu->type != PERF_TYPE_SOFTWARE)
10736 idr_remove(&pmu_idr, pmu->type);
10737 if (pmu_bus_running) {
10738 if (pmu->nr_addr_filters)
10739 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
10740 device_del(pmu->dev);
10741 put_device(pmu->dev);
10743 free_pmu_context(pmu);
10744 mutex_unlock(&pmus_lock);
10746 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
10748 static inline bool has_extended_regs(struct perf_event *event)
10750 return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
10751 (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
10754 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
10756 struct perf_event_context *ctx = NULL;
10759 if (!try_module_get(pmu->module))
10763 * A number of pmu->event_init() methods iterate the sibling_list to,
10764 * for example, validate if the group fits on the PMU. Therefore,
10765 * if this is a sibling event, acquire the ctx->mutex to protect
10766 * the sibling_list.
10768 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
10770 * This ctx->mutex can nest when we're called through
10771 * inheritance. See the perf_event_ctx_lock_nested() comment.
10773 ctx = perf_event_ctx_lock_nested(event->group_leader,
10774 SINGLE_DEPTH_NESTING);
10779 ret = pmu->event_init(event);
10782 perf_event_ctx_unlock(event->group_leader, ctx);
10785 if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
10786 has_extended_regs(event))
10789 if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
10790 event_has_any_exclude_flag(event))
10793 if (ret && event->destroy)
10794 event->destroy(event);
10798 module_put(pmu->module);
10803 static struct pmu *perf_init_event(struct perf_event *event)
10805 int idx, type, ret;
10808 idx = srcu_read_lock(&pmus_srcu);
10810 /* Try parent's PMU first: */
10811 if (event->parent && event->parent->pmu) {
10812 pmu = event->parent->pmu;
10813 ret = perf_try_init_event(pmu, event);
10819 * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
10820 * are often aliases for PERF_TYPE_RAW.
10822 type = event->attr.type;
10823 if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE)
10824 type = PERF_TYPE_RAW;
10828 pmu = idr_find(&pmu_idr, type);
10831 ret = perf_try_init_event(pmu, event);
10832 if (ret == -ENOENT && event->attr.type != type) {
10833 type = event->attr.type;
10838 pmu = ERR_PTR(ret);
10843 list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
10844 ret = perf_try_init_event(pmu, event);
10848 if (ret != -ENOENT) {
10849 pmu = ERR_PTR(ret);
10853 pmu = ERR_PTR(-ENOENT);
10855 srcu_read_unlock(&pmus_srcu, idx);
10860 static void attach_sb_event(struct perf_event *event)
10862 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
10864 raw_spin_lock(&pel->lock);
10865 list_add_rcu(&event->sb_list, &pel->list);
10866 raw_spin_unlock(&pel->lock);
10870 * We keep a list of all !task (and therefore per-cpu) events
10871 * that need to receive side-band records.
10873 * This avoids having to scan all the various PMU per-cpu contexts
10874 * looking for them.
10876 static void account_pmu_sb_event(struct perf_event *event)
10878 if (is_sb_event(event))
10879 attach_sb_event(event);
10882 static void account_event_cpu(struct perf_event *event, int cpu)
10887 if (is_cgroup_event(event))
10888 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
10891 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
10892 static void account_freq_event_nohz(void)
10894 #ifdef CONFIG_NO_HZ_FULL
10895 /* Lock so we don't race with concurrent unaccount */
10896 spin_lock(&nr_freq_lock);
10897 if (atomic_inc_return(&nr_freq_events) == 1)
10898 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
10899 spin_unlock(&nr_freq_lock);
10903 static void account_freq_event(void)
10905 if (tick_nohz_full_enabled())
10906 account_freq_event_nohz();
10908 atomic_inc(&nr_freq_events);
10912 static void account_event(struct perf_event *event)
10919 if (event->attach_state & PERF_ATTACH_TASK)
10921 if (event->attr.mmap || event->attr.mmap_data)
10922 atomic_inc(&nr_mmap_events);
10923 if (event->attr.comm)
10924 atomic_inc(&nr_comm_events);
10925 if (event->attr.namespaces)
10926 atomic_inc(&nr_namespaces_events);
10927 if (event->attr.cgroup)
10928 atomic_inc(&nr_cgroup_events);
10929 if (event->attr.task)
10930 atomic_inc(&nr_task_events);
10931 if (event->attr.freq)
10932 account_freq_event();
10933 if (event->attr.context_switch) {
10934 atomic_inc(&nr_switch_events);
10937 if (has_branch_stack(event))
10939 if (is_cgroup_event(event))
10941 if (event->attr.ksymbol)
10942 atomic_inc(&nr_ksymbol_events);
10943 if (event->attr.bpf_event)
10944 atomic_inc(&nr_bpf_events);
10948 * We need the mutex here because static_branch_enable()
10949 * must complete *before* the perf_sched_count increment
10952 if (atomic_inc_not_zero(&perf_sched_count))
10955 mutex_lock(&perf_sched_mutex);
10956 if (!atomic_read(&perf_sched_count)) {
10957 static_branch_enable(&perf_sched_events);
10959 * Guarantee that all CPUs observe they key change and
10960 * call the perf scheduling hooks before proceeding to
10961 * install events that need them.
10966 * Now that we have waited for the sync_sched(), allow further
10967 * increments to by-pass the mutex.
10969 atomic_inc(&perf_sched_count);
10970 mutex_unlock(&perf_sched_mutex);
10974 account_event_cpu(event, event->cpu);
10976 account_pmu_sb_event(event);
10980 * Allocate and initialize an event structure
10982 static struct perf_event *
10983 perf_event_alloc(struct perf_event_attr *attr, int cpu,
10984 struct task_struct *task,
10985 struct perf_event *group_leader,
10986 struct perf_event *parent_event,
10987 perf_overflow_handler_t overflow_handler,
10988 void *context, int cgroup_fd)
10991 struct perf_event *event;
10992 struct hw_perf_event *hwc;
10993 long err = -EINVAL;
10995 if ((unsigned)cpu >= nr_cpu_ids) {
10996 if (!task || cpu != -1)
10997 return ERR_PTR(-EINVAL);
11000 event = kzalloc(sizeof(*event), GFP_KERNEL);
11002 return ERR_PTR(-ENOMEM);
11005 * Single events are their own group leaders, with an
11006 * empty sibling list:
11009 group_leader = event;
11011 mutex_init(&event->child_mutex);
11012 INIT_LIST_HEAD(&event->child_list);
11014 INIT_LIST_HEAD(&event->event_entry);
11015 INIT_LIST_HEAD(&event->sibling_list);
11016 INIT_LIST_HEAD(&event->active_list);
11017 init_event_group(event);
11018 INIT_LIST_HEAD(&event->rb_entry);
11019 INIT_LIST_HEAD(&event->active_entry);
11020 INIT_LIST_HEAD(&event->addr_filters.list);
11021 INIT_HLIST_NODE(&event->hlist_entry);
11024 init_waitqueue_head(&event->waitq);
11025 event->pending_disable = -1;
11026 init_irq_work(&event->pending, perf_pending_event);
11028 mutex_init(&event->mmap_mutex);
11029 raw_spin_lock_init(&event->addr_filters.lock);
11031 atomic_long_set(&event->refcount, 1);
11033 event->attr = *attr;
11034 event->group_leader = group_leader;
11038 event->parent = parent_event;
11040 event->ns = get_pid_ns(task_active_pid_ns(current));
11041 event->id = atomic64_inc_return(&perf_event_id);
11043 event->state = PERF_EVENT_STATE_INACTIVE;
11046 event->attach_state = PERF_ATTACH_TASK;
11048 * XXX pmu::event_init needs to know what task to account to
11049 * and we cannot use the ctx information because we need the
11050 * pmu before we get a ctx.
11052 event->hw.target = get_task_struct(task);
11055 event->clock = &local_clock;
11057 event->clock = parent_event->clock;
11059 if (!overflow_handler && parent_event) {
11060 overflow_handler = parent_event->overflow_handler;
11061 context = parent_event->overflow_handler_context;
11062 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
11063 if (overflow_handler == bpf_overflow_handler) {
11064 struct bpf_prog *prog = parent_event->prog;
11066 bpf_prog_inc(prog);
11067 event->prog = prog;
11068 event->orig_overflow_handler =
11069 parent_event->orig_overflow_handler;
11074 if (overflow_handler) {
11075 event->overflow_handler = overflow_handler;
11076 event->overflow_handler_context = context;
11077 } else if (is_write_backward(event)){
11078 event->overflow_handler = perf_event_output_backward;
11079 event->overflow_handler_context = NULL;
11081 event->overflow_handler = perf_event_output_forward;
11082 event->overflow_handler_context = NULL;
11085 perf_event__state_init(event);
11090 hwc->sample_period = attr->sample_period;
11091 if (attr->freq && attr->sample_freq)
11092 hwc->sample_period = 1;
11093 hwc->last_period = hwc->sample_period;
11095 local64_set(&hwc->period_left, hwc->sample_period);
11098 * We currently do not support PERF_SAMPLE_READ on inherited events.
11099 * See perf_output_read().
11101 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
11104 if (!has_branch_stack(event))
11105 event->attr.branch_sample_type = 0;
11107 pmu = perf_init_event(event);
11109 err = PTR_ERR(pmu);
11114 * Disallow uncore-cgroup events, they don't make sense as the cgroup will
11115 * be different on other CPUs in the uncore mask.
11117 if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) {
11122 if (event->attr.aux_output &&
11123 !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
11128 if (cgroup_fd != -1) {
11129 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
11134 err = exclusive_event_init(event);
11138 if (has_addr_filter(event)) {
11139 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
11140 sizeof(struct perf_addr_filter_range),
11142 if (!event->addr_filter_ranges) {
11148 * Clone the parent's vma offsets: they are valid until exec()
11149 * even if the mm is not shared with the parent.
11151 if (event->parent) {
11152 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
11154 raw_spin_lock_irq(&ifh->lock);
11155 memcpy(event->addr_filter_ranges,
11156 event->parent->addr_filter_ranges,
11157 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
11158 raw_spin_unlock_irq(&ifh->lock);
11161 /* force hw sync on the address filters */
11162 event->addr_filters_gen = 1;
11165 if (!event->parent) {
11166 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
11167 err = get_callchain_buffers(attr->sample_max_stack);
11169 goto err_addr_filters;
11173 err = security_perf_event_alloc(event);
11175 goto err_callchain_buffer;
11177 /* symmetric to unaccount_event() in _free_event() */
11178 account_event(event);
11182 err_callchain_buffer:
11183 if (!event->parent) {
11184 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
11185 put_callchain_buffers();
11188 kfree(event->addr_filter_ranges);
11191 exclusive_event_destroy(event);
11194 if (is_cgroup_event(event))
11195 perf_detach_cgroup(event);
11196 if (event->destroy)
11197 event->destroy(event);
11198 module_put(pmu->module);
11201 put_pid_ns(event->ns);
11202 if (event->hw.target)
11203 put_task_struct(event->hw.target);
11206 return ERR_PTR(err);
11209 static int perf_copy_attr(struct perf_event_attr __user *uattr,
11210 struct perf_event_attr *attr)
11215 /* Zero the full structure, so that a short copy will be nice. */
11216 memset(attr, 0, sizeof(*attr));
11218 ret = get_user(size, &uattr->size);
11222 /* ABI compatibility quirk: */
11224 size = PERF_ATTR_SIZE_VER0;
11225 if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
11228 ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
11237 if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
11240 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
11243 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
11246 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
11247 u64 mask = attr->branch_sample_type;
11249 /* only using defined bits */
11250 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
11253 /* at least one branch bit must be set */
11254 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
11257 /* propagate priv level, when not set for branch */
11258 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
11260 /* exclude_kernel checked on syscall entry */
11261 if (!attr->exclude_kernel)
11262 mask |= PERF_SAMPLE_BRANCH_KERNEL;
11264 if (!attr->exclude_user)
11265 mask |= PERF_SAMPLE_BRANCH_USER;
11267 if (!attr->exclude_hv)
11268 mask |= PERF_SAMPLE_BRANCH_HV;
11270 * adjust user setting (for HW filter setup)
11272 attr->branch_sample_type = mask;
11274 /* privileged levels capture (kernel, hv): check permissions */
11275 if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
11276 ret = perf_allow_kernel(attr);
11282 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
11283 ret = perf_reg_validate(attr->sample_regs_user);
11288 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
11289 if (!arch_perf_have_user_stack_dump())
11293 * We have __u32 type for the size, but so far
11294 * we can only use __u16 as maximum due to the
11295 * __u16 sample size limit.
11297 if (attr->sample_stack_user >= USHRT_MAX)
11299 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
11303 if (!attr->sample_max_stack)
11304 attr->sample_max_stack = sysctl_perf_event_max_stack;
11306 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
11307 ret = perf_reg_validate(attr->sample_regs_intr);
11309 #ifndef CONFIG_CGROUP_PERF
11310 if (attr->sample_type & PERF_SAMPLE_CGROUP)
11318 put_user(sizeof(*attr), &uattr->size);
11324 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
11326 struct perf_buffer *rb = NULL;
11332 /* don't allow circular references */
11333 if (event == output_event)
11337 * Don't allow cross-cpu buffers
11339 if (output_event->cpu != event->cpu)
11343 * If its not a per-cpu rb, it must be the same task.
11345 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
11349 * Mixing clocks in the same buffer is trouble you don't need.
11351 if (output_event->clock != event->clock)
11355 * Either writing ring buffer from beginning or from end.
11356 * Mixing is not allowed.
11358 if (is_write_backward(output_event) != is_write_backward(event))
11362 * If both events generate aux data, they must be on the same PMU
11364 if (has_aux(event) && has_aux(output_event) &&
11365 event->pmu != output_event->pmu)
11369 mutex_lock(&event->mmap_mutex);
11370 /* Can't redirect output if we've got an active mmap() */
11371 if (atomic_read(&event->mmap_count))
11374 if (output_event) {
11375 /* get the rb we want to redirect to */
11376 rb = ring_buffer_get(output_event);
11381 ring_buffer_attach(event, rb);
11385 mutex_unlock(&event->mmap_mutex);
11391 static void mutex_lock_double(struct mutex *a, struct mutex *b)
11397 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
11400 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
11402 bool nmi_safe = false;
11405 case CLOCK_MONOTONIC:
11406 event->clock = &ktime_get_mono_fast_ns;
11410 case CLOCK_MONOTONIC_RAW:
11411 event->clock = &ktime_get_raw_fast_ns;
11415 case CLOCK_REALTIME:
11416 event->clock = &ktime_get_real_ns;
11419 case CLOCK_BOOTTIME:
11420 event->clock = &ktime_get_boottime_ns;
11424 event->clock = &ktime_get_clocktai_ns;
11431 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
11438 * Variation on perf_event_ctx_lock_nested(), except we take two context
11441 static struct perf_event_context *
11442 __perf_event_ctx_lock_double(struct perf_event *group_leader,
11443 struct perf_event_context *ctx)
11445 struct perf_event_context *gctx;
11449 gctx = READ_ONCE(group_leader->ctx);
11450 if (!refcount_inc_not_zero(&gctx->refcount)) {
11456 mutex_lock_double(&gctx->mutex, &ctx->mutex);
11458 if (group_leader->ctx != gctx) {
11459 mutex_unlock(&ctx->mutex);
11460 mutex_unlock(&gctx->mutex);
11469 * sys_perf_event_open - open a performance event, associate it to a task/cpu
11471 * @attr_uptr: event_id type attributes for monitoring/sampling
11474 * @group_fd: group leader event fd
11476 SYSCALL_DEFINE5(perf_event_open,
11477 struct perf_event_attr __user *, attr_uptr,
11478 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
11480 struct perf_event *group_leader = NULL, *output_event = NULL;
11481 struct perf_event *event, *sibling;
11482 struct perf_event_attr attr;
11483 struct perf_event_context *ctx, *uninitialized_var(gctx);
11484 struct file *event_file = NULL;
11485 struct fd group = {NULL, 0};
11486 struct task_struct *task = NULL;
11489 int move_group = 0;
11491 int f_flags = O_RDWR;
11492 int cgroup_fd = -1;
11494 /* for future expandability... */
11495 if (flags & ~PERF_FLAG_ALL)
11498 /* Do we allow access to perf_event_open(2) ? */
11499 err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
11503 err = perf_copy_attr(attr_uptr, &attr);
11507 if (!attr.exclude_kernel) {
11508 err = perf_allow_kernel(&attr);
11513 if (attr.namespaces) {
11514 if (!capable(CAP_SYS_ADMIN))
11519 if (attr.sample_freq > sysctl_perf_event_sample_rate)
11522 if (attr.sample_period & (1ULL << 63))
11526 /* Only privileged users can get physical addresses */
11527 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
11528 err = perf_allow_kernel(&attr);
11533 err = security_locked_down(LOCKDOWN_PERF);
11534 if (err && (attr.sample_type & PERF_SAMPLE_REGS_INTR))
11535 /* REGS_INTR can leak data, lockdown must prevent this */
11541 * In cgroup mode, the pid argument is used to pass the fd
11542 * opened to the cgroup directory in cgroupfs. The cpu argument
11543 * designates the cpu on which to monitor threads from that
11546 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
11549 if (flags & PERF_FLAG_FD_CLOEXEC)
11550 f_flags |= O_CLOEXEC;
11552 event_fd = get_unused_fd_flags(f_flags);
11556 if (group_fd != -1) {
11557 err = perf_fget_light(group_fd, &group);
11560 group_leader = group.file->private_data;
11561 if (flags & PERF_FLAG_FD_OUTPUT)
11562 output_event = group_leader;
11563 if (flags & PERF_FLAG_FD_NO_GROUP)
11564 group_leader = NULL;
11567 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
11568 task = find_lively_task_by_vpid(pid);
11569 if (IS_ERR(task)) {
11570 err = PTR_ERR(task);
11575 if (task && group_leader &&
11576 group_leader->attr.inherit != attr.inherit) {
11582 err = mutex_lock_interruptible(&task->signal->exec_update_mutex);
11587 * Reuse ptrace permission checks for now.
11589 * We must hold exec_update_mutex across this and any potential
11590 * perf_install_in_context() call for this new event to
11591 * serialize against exec() altering our credentials (and the
11592 * perf_event_exit_task() that could imply).
11595 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
11599 if (flags & PERF_FLAG_PID_CGROUP)
11602 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
11603 NULL, NULL, cgroup_fd);
11604 if (IS_ERR(event)) {
11605 err = PTR_ERR(event);
11609 if (is_sampling_event(event)) {
11610 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
11617 * Special case software events and allow them to be part of
11618 * any hardware group.
11622 if (attr.use_clockid) {
11623 err = perf_event_set_clock(event, attr.clockid);
11628 if (pmu->task_ctx_nr == perf_sw_context)
11629 event->event_caps |= PERF_EV_CAP_SOFTWARE;
11631 if (group_leader) {
11632 if (is_software_event(event) &&
11633 !in_software_context(group_leader)) {
11635 * If the event is a sw event, but the group_leader
11636 * is on hw context.
11638 * Allow the addition of software events to hw
11639 * groups, this is safe because software events
11640 * never fail to schedule.
11642 pmu = group_leader->ctx->pmu;
11643 } else if (!is_software_event(event) &&
11644 is_software_event(group_leader) &&
11645 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11647 * In case the group is a pure software group, and we
11648 * try to add a hardware event, move the whole group to
11649 * the hardware context.
11656 * Get the target context (task or percpu):
11658 ctx = find_get_context(pmu, task, event);
11660 err = PTR_ERR(ctx);
11665 * Look up the group leader (we will attach this event to it):
11667 if (group_leader) {
11671 * Do not allow a recursive hierarchy (this new sibling
11672 * becoming part of another group-sibling):
11674 if (group_leader->group_leader != group_leader)
11677 /* All events in a group should have the same clock */
11678 if (group_leader->clock != event->clock)
11682 * Make sure we're both events for the same CPU;
11683 * grouping events for different CPUs is broken; since
11684 * you can never concurrently schedule them anyhow.
11686 if (group_leader->cpu != event->cpu)
11690 * Make sure we're both on the same task, or both
11693 if (group_leader->ctx->task != ctx->task)
11697 * Do not allow to attach to a group in a different task
11698 * or CPU context. If we're moving SW events, we'll fix
11699 * this up later, so allow that.
11701 if (!move_group && group_leader->ctx != ctx)
11705 * Only a group leader can be exclusive or pinned
11707 if (attr.exclusive || attr.pinned)
11711 if (output_event) {
11712 err = perf_event_set_output(event, output_event);
11717 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
11719 if (IS_ERR(event_file)) {
11720 err = PTR_ERR(event_file);
11726 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
11728 if (gctx->task == TASK_TOMBSTONE) {
11734 * Check if we raced against another sys_perf_event_open() call
11735 * moving the software group underneath us.
11737 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11739 * If someone moved the group out from under us, check
11740 * if this new event wound up on the same ctx, if so
11741 * its the regular !move_group case, otherwise fail.
11747 perf_event_ctx_unlock(group_leader, gctx);
11753 * Failure to create exclusive events returns -EBUSY.
11756 if (!exclusive_event_installable(group_leader, ctx))
11759 for_each_sibling_event(sibling, group_leader) {
11760 if (!exclusive_event_installable(sibling, ctx))
11764 mutex_lock(&ctx->mutex);
11767 if (ctx->task == TASK_TOMBSTONE) {
11772 if (!perf_event_validate_size(event)) {
11779 * Check if the @cpu we're creating an event for is online.
11781 * We use the perf_cpu_context::ctx::mutex to serialize against
11782 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11784 struct perf_cpu_context *cpuctx =
11785 container_of(ctx, struct perf_cpu_context, ctx);
11787 if (!cpuctx->online) {
11793 if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
11799 * Must be under the same ctx::mutex as perf_install_in_context(),
11800 * because we need to serialize with concurrent event creation.
11802 if (!exclusive_event_installable(event, ctx)) {
11807 WARN_ON_ONCE(ctx->parent_ctx);
11810 * This is the point on no return; we cannot fail hereafter. This is
11811 * where we start modifying current state.
11816 * See perf_event_ctx_lock() for comments on the details
11817 * of swizzling perf_event::ctx.
11819 perf_remove_from_context(group_leader, 0);
11822 for_each_sibling_event(sibling, group_leader) {
11823 perf_remove_from_context(sibling, 0);
11828 * Wait for everybody to stop referencing the events through
11829 * the old lists, before installing it on new lists.
11834 * Install the group siblings before the group leader.
11836 * Because a group leader will try and install the entire group
11837 * (through the sibling list, which is still in-tact), we can
11838 * end up with siblings installed in the wrong context.
11840 * By installing siblings first we NO-OP because they're not
11841 * reachable through the group lists.
11843 for_each_sibling_event(sibling, group_leader) {
11844 perf_event__state_init(sibling);
11845 perf_install_in_context(ctx, sibling, sibling->cpu);
11850 * Removing from the context ends up with disabled
11851 * event. What we want here is event in the initial
11852 * startup state, ready to be add into new context.
11854 perf_event__state_init(group_leader);
11855 perf_install_in_context(ctx, group_leader, group_leader->cpu);
11860 * Precalculate sample_data sizes; do while holding ctx::mutex such
11861 * that we're serialized against further additions and before
11862 * perf_install_in_context() which is the point the event is active and
11863 * can use these values.
11865 perf_event__header_size(event);
11866 perf_event__id_header_size(event);
11868 event->owner = current;
11870 perf_install_in_context(ctx, event, event->cpu);
11871 perf_unpin_context(ctx);
11874 perf_event_ctx_unlock(group_leader, gctx);
11875 mutex_unlock(&ctx->mutex);
11878 mutex_unlock(&task->signal->exec_update_mutex);
11879 put_task_struct(task);
11882 mutex_lock(¤t->perf_event_mutex);
11883 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
11884 mutex_unlock(¤t->perf_event_mutex);
11887 * Drop the reference on the group_event after placing the
11888 * new event on the sibling_list. This ensures destruction
11889 * of the group leader will find the pointer to itself in
11890 * perf_group_detach().
11893 fd_install(event_fd, event_file);
11898 perf_event_ctx_unlock(group_leader, gctx);
11899 mutex_unlock(&ctx->mutex);
11903 perf_unpin_context(ctx);
11907 * If event_file is set, the fput() above will have called ->release()
11908 * and that will take care of freeing the event.
11914 mutex_unlock(&task->signal->exec_update_mutex);
11917 put_task_struct(task);
11921 put_unused_fd(event_fd);
11926 * perf_event_create_kernel_counter
11928 * @attr: attributes of the counter to create
11929 * @cpu: cpu in which the counter is bound
11930 * @task: task to profile (NULL for percpu)
11932 struct perf_event *
11933 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
11934 struct task_struct *task,
11935 perf_overflow_handler_t overflow_handler,
11938 struct perf_event_context *ctx;
11939 struct perf_event *event;
11943 * Grouping is not supported for kernel events, neither is 'AUX',
11944 * make sure the caller's intentions are adjusted.
11946 if (attr->aux_output)
11947 return ERR_PTR(-EINVAL);
11949 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
11950 overflow_handler, context, -1);
11951 if (IS_ERR(event)) {
11952 err = PTR_ERR(event);
11956 /* Mark owner so we could distinguish it from user events. */
11957 event->owner = TASK_TOMBSTONE;
11960 * Get the target context (task or percpu):
11962 ctx = find_get_context(event->pmu, task, event);
11964 err = PTR_ERR(ctx);
11968 WARN_ON_ONCE(ctx->parent_ctx);
11969 mutex_lock(&ctx->mutex);
11970 if (ctx->task == TASK_TOMBSTONE) {
11977 * Check if the @cpu we're creating an event for is online.
11979 * We use the perf_cpu_context::ctx::mutex to serialize against
11980 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11982 struct perf_cpu_context *cpuctx =
11983 container_of(ctx, struct perf_cpu_context, ctx);
11984 if (!cpuctx->online) {
11990 if (!exclusive_event_installable(event, ctx)) {
11995 perf_install_in_context(ctx, event, event->cpu);
11996 perf_unpin_context(ctx);
11997 mutex_unlock(&ctx->mutex);
12002 mutex_unlock(&ctx->mutex);
12003 perf_unpin_context(ctx);
12008 return ERR_PTR(err);
12010 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
12012 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
12014 struct perf_event_context *src_ctx;
12015 struct perf_event_context *dst_ctx;
12016 struct perf_event *event, *tmp;
12019 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
12020 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
12023 * See perf_event_ctx_lock() for comments on the details
12024 * of swizzling perf_event::ctx.
12026 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
12027 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
12029 perf_remove_from_context(event, 0);
12030 unaccount_event_cpu(event, src_cpu);
12032 list_add(&event->migrate_entry, &events);
12036 * Wait for the events to quiesce before re-instating them.
12041 * Re-instate events in 2 passes.
12043 * Skip over group leaders and only install siblings on this first
12044 * pass, siblings will not get enabled without a leader, however a
12045 * leader will enable its siblings, even if those are still on the old
12048 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12049 if (event->group_leader == event)
12052 list_del(&event->migrate_entry);
12053 if (event->state >= PERF_EVENT_STATE_OFF)
12054 event->state = PERF_EVENT_STATE_INACTIVE;
12055 account_event_cpu(event, dst_cpu);
12056 perf_install_in_context(dst_ctx, event, dst_cpu);
12061 * Once all the siblings are setup properly, install the group leaders
12064 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12065 list_del(&event->migrate_entry);
12066 if (event->state >= PERF_EVENT_STATE_OFF)
12067 event->state = PERF_EVENT_STATE_INACTIVE;
12068 account_event_cpu(event, dst_cpu);
12069 perf_install_in_context(dst_ctx, event, dst_cpu);
12072 mutex_unlock(&dst_ctx->mutex);
12073 mutex_unlock(&src_ctx->mutex);
12075 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
12077 static void sync_child_event(struct perf_event *child_event,
12078 struct task_struct *child)
12080 struct perf_event *parent_event = child_event->parent;
12083 if (child_event->attr.inherit_stat)
12084 perf_event_read_event(child_event, child);
12086 child_val = perf_event_count(child_event);
12089 * Add back the child's count to the parent's count:
12091 atomic64_add(child_val, &parent_event->child_count);
12092 atomic64_add(child_event->total_time_enabled,
12093 &parent_event->child_total_time_enabled);
12094 atomic64_add(child_event->total_time_running,
12095 &parent_event->child_total_time_running);
12099 perf_event_exit_event(struct perf_event *child_event,
12100 struct perf_event_context *child_ctx,
12101 struct task_struct *child)
12103 struct perf_event *parent_event = child_event->parent;
12106 * Do not destroy the 'original' grouping; because of the context
12107 * switch optimization the original events could've ended up in a
12108 * random child task.
12110 * If we were to destroy the original group, all group related
12111 * operations would cease to function properly after this random
12114 * Do destroy all inherited groups, we don't care about those
12115 * and being thorough is better.
12117 raw_spin_lock_irq(&child_ctx->lock);
12118 WARN_ON_ONCE(child_ctx->is_active);
12121 perf_group_detach(child_event);
12122 list_del_event(child_event, child_ctx);
12123 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
12124 raw_spin_unlock_irq(&child_ctx->lock);
12127 * Parent events are governed by their filedesc, retain them.
12129 if (!parent_event) {
12130 perf_event_wakeup(child_event);
12134 * Child events can be cleaned up.
12137 sync_child_event(child_event, child);
12140 * Remove this event from the parent's list
12142 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
12143 mutex_lock(&parent_event->child_mutex);
12144 list_del_init(&child_event->child_list);
12145 mutex_unlock(&parent_event->child_mutex);
12148 * Kick perf_poll() for is_event_hup().
12150 perf_event_wakeup(parent_event);
12151 free_event(child_event);
12152 put_event(parent_event);
12155 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
12157 struct perf_event_context *child_ctx, *clone_ctx = NULL;
12158 struct perf_event *child_event, *next;
12160 WARN_ON_ONCE(child != current);
12162 child_ctx = perf_pin_task_context(child, ctxn);
12167 * In order to reduce the amount of tricky in ctx tear-down, we hold
12168 * ctx::mutex over the entire thing. This serializes against almost
12169 * everything that wants to access the ctx.
12171 * The exception is sys_perf_event_open() /
12172 * perf_event_create_kernel_count() which does find_get_context()
12173 * without ctx::mutex (it cannot because of the move_group double mutex
12174 * lock thing). See the comments in perf_install_in_context().
12176 mutex_lock(&child_ctx->mutex);
12179 * In a single ctx::lock section, de-schedule the events and detach the
12180 * context from the task such that we cannot ever get it scheduled back
12183 raw_spin_lock_irq(&child_ctx->lock);
12184 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
12187 * Now that the context is inactive, destroy the task <-> ctx relation
12188 * and mark the context dead.
12190 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
12191 put_ctx(child_ctx); /* cannot be last */
12192 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
12193 put_task_struct(current); /* cannot be last */
12195 clone_ctx = unclone_ctx(child_ctx);
12196 raw_spin_unlock_irq(&child_ctx->lock);
12199 put_ctx(clone_ctx);
12202 * Report the task dead after unscheduling the events so that we
12203 * won't get any samples after PERF_RECORD_EXIT. We can however still
12204 * get a few PERF_RECORD_READ events.
12206 perf_event_task(child, child_ctx, 0);
12208 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
12209 perf_event_exit_event(child_event, child_ctx, child);
12211 mutex_unlock(&child_ctx->mutex);
12213 put_ctx(child_ctx);
12217 * When a child task exits, feed back event values to parent events.
12219 * Can be called with exec_update_mutex held when called from
12220 * install_exec_creds().
12222 void perf_event_exit_task(struct task_struct *child)
12224 struct perf_event *event, *tmp;
12227 mutex_lock(&child->perf_event_mutex);
12228 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
12230 list_del_init(&event->owner_entry);
12233 * Ensure the list deletion is visible before we clear
12234 * the owner, closes a race against perf_release() where
12235 * we need to serialize on the owner->perf_event_mutex.
12237 smp_store_release(&event->owner, NULL);
12239 mutex_unlock(&child->perf_event_mutex);
12241 for_each_task_context_nr(ctxn)
12242 perf_event_exit_task_context(child, ctxn);
12245 * The perf_event_exit_task_context calls perf_event_task
12246 * with child's task_ctx, which generates EXIT events for
12247 * child contexts and sets child->perf_event_ctxp[] to NULL.
12248 * At this point we need to send EXIT events to cpu contexts.
12250 perf_event_task(child, NULL, 0);
12253 static void perf_free_event(struct perf_event *event,
12254 struct perf_event_context *ctx)
12256 struct perf_event *parent = event->parent;
12258 if (WARN_ON_ONCE(!parent))
12261 mutex_lock(&parent->child_mutex);
12262 list_del_init(&event->child_list);
12263 mutex_unlock(&parent->child_mutex);
12267 raw_spin_lock_irq(&ctx->lock);
12268 perf_group_detach(event);
12269 list_del_event(event, ctx);
12270 raw_spin_unlock_irq(&ctx->lock);
12275 * Free a context as created by inheritance by perf_event_init_task() below,
12276 * used by fork() in case of fail.
12278 * Even though the task has never lived, the context and events have been
12279 * exposed through the child_list, so we must take care tearing it all down.
12281 void perf_event_free_task(struct task_struct *task)
12283 struct perf_event_context *ctx;
12284 struct perf_event *event, *tmp;
12287 for_each_task_context_nr(ctxn) {
12288 ctx = task->perf_event_ctxp[ctxn];
12292 mutex_lock(&ctx->mutex);
12293 raw_spin_lock_irq(&ctx->lock);
12295 * Destroy the task <-> ctx relation and mark the context dead.
12297 * This is important because even though the task hasn't been
12298 * exposed yet the context has been (through child_list).
12300 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
12301 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
12302 put_task_struct(task); /* cannot be last */
12303 raw_spin_unlock_irq(&ctx->lock);
12305 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
12306 perf_free_event(event, ctx);
12308 mutex_unlock(&ctx->mutex);
12311 * perf_event_release_kernel() could've stolen some of our
12312 * child events and still have them on its free_list. In that
12313 * case we must wait for these events to have been freed (in
12314 * particular all their references to this task must've been
12317 * Without this copy_process() will unconditionally free this
12318 * task (irrespective of its reference count) and
12319 * _free_event()'s put_task_struct(event->hw.target) will be a
12322 * Wait for all events to drop their context reference.
12324 wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
12325 put_ctx(ctx); /* must be last */
12329 void perf_event_delayed_put(struct task_struct *task)
12333 for_each_task_context_nr(ctxn)
12334 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
12337 struct file *perf_event_get(unsigned int fd)
12339 struct file *file = fget(fd);
12341 return ERR_PTR(-EBADF);
12343 if (file->f_op != &perf_fops) {
12345 return ERR_PTR(-EBADF);
12351 const struct perf_event *perf_get_event(struct file *file)
12353 if (file->f_op != &perf_fops)
12354 return ERR_PTR(-EINVAL);
12356 return file->private_data;
12359 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
12362 return ERR_PTR(-EINVAL);
12364 return &event->attr;
12368 * Inherit an event from parent task to child task.
12371 * - valid pointer on success
12372 * - NULL for orphaned events
12373 * - IS_ERR() on error
12375 static struct perf_event *
12376 inherit_event(struct perf_event *parent_event,
12377 struct task_struct *parent,
12378 struct perf_event_context *parent_ctx,
12379 struct task_struct *child,
12380 struct perf_event *group_leader,
12381 struct perf_event_context *child_ctx)
12383 enum perf_event_state parent_state = parent_event->state;
12384 struct perf_event *child_event;
12385 unsigned long flags;
12388 * Instead of creating recursive hierarchies of events,
12389 * we link inherited events back to the original parent,
12390 * which has a filp for sure, which we use as the reference
12393 if (parent_event->parent)
12394 parent_event = parent_event->parent;
12396 child_event = perf_event_alloc(&parent_event->attr,
12399 group_leader, parent_event,
12401 if (IS_ERR(child_event))
12402 return child_event;
12405 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
12406 !child_ctx->task_ctx_data) {
12407 struct pmu *pmu = child_event->pmu;
12409 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
12411 if (!child_ctx->task_ctx_data) {
12412 free_event(child_event);
12413 return ERR_PTR(-ENOMEM);
12418 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
12419 * must be under the same lock in order to serialize against
12420 * perf_event_release_kernel(), such that either we must observe
12421 * is_orphaned_event() or they will observe us on the child_list.
12423 mutex_lock(&parent_event->child_mutex);
12424 if (is_orphaned_event(parent_event) ||
12425 !atomic_long_inc_not_zero(&parent_event->refcount)) {
12426 mutex_unlock(&parent_event->child_mutex);
12427 /* task_ctx_data is freed with child_ctx */
12428 free_event(child_event);
12432 get_ctx(child_ctx);
12435 * Make the child state follow the state of the parent event,
12436 * not its attr.disabled bit. We hold the parent's mutex,
12437 * so we won't race with perf_event_{en, dis}able_family.
12439 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
12440 child_event->state = PERF_EVENT_STATE_INACTIVE;
12442 child_event->state = PERF_EVENT_STATE_OFF;
12444 if (parent_event->attr.freq) {
12445 u64 sample_period = parent_event->hw.sample_period;
12446 struct hw_perf_event *hwc = &child_event->hw;
12448 hwc->sample_period = sample_period;
12449 hwc->last_period = sample_period;
12451 local64_set(&hwc->period_left, sample_period);
12454 child_event->ctx = child_ctx;
12455 child_event->overflow_handler = parent_event->overflow_handler;
12456 child_event->overflow_handler_context
12457 = parent_event->overflow_handler_context;
12460 * Precalculate sample_data sizes
12462 perf_event__header_size(child_event);
12463 perf_event__id_header_size(child_event);
12466 * Link it up in the child's context:
12468 raw_spin_lock_irqsave(&child_ctx->lock, flags);
12469 add_event_to_ctx(child_event, child_ctx);
12470 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
12473 * Link this into the parent event's child list
12475 list_add_tail(&child_event->child_list, &parent_event->child_list);
12476 mutex_unlock(&parent_event->child_mutex);
12478 return child_event;
12482 * Inherits an event group.
12484 * This will quietly suppress orphaned events; !inherit_event() is not an error.
12485 * This matches with perf_event_release_kernel() removing all child events.
12491 static int inherit_group(struct perf_event *parent_event,
12492 struct task_struct *parent,
12493 struct perf_event_context *parent_ctx,
12494 struct task_struct *child,
12495 struct perf_event_context *child_ctx)
12497 struct perf_event *leader;
12498 struct perf_event *sub;
12499 struct perf_event *child_ctr;
12501 leader = inherit_event(parent_event, parent, parent_ctx,
12502 child, NULL, child_ctx);
12503 if (IS_ERR(leader))
12504 return PTR_ERR(leader);
12506 * @leader can be NULL here because of is_orphaned_event(). In this
12507 * case inherit_event() will create individual events, similar to what
12508 * perf_group_detach() would do anyway.
12510 for_each_sibling_event(sub, parent_event) {
12511 child_ctr = inherit_event(sub, parent, parent_ctx,
12512 child, leader, child_ctx);
12513 if (IS_ERR(child_ctr))
12514 return PTR_ERR(child_ctr);
12516 if (sub->aux_event == parent_event && child_ctr &&
12517 !perf_get_aux_event(child_ctr, leader))
12524 * Creates the child task context and tries to inherit the event-group.
12526 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
12527 * inherited_all set when we 'fail' to inherit an orphaned event; this is
12528 * consistent with perf_event_release_kernel() removing all child events.
12535 inherit_task_group(struct perf_event *event, struct task_struct *parent,
12536 struct perf_event_context *parent_ctx,
12537 struct task_struct *child, int ctxn,
12538 int *inherited_all)
12541 struct perf_event_context *child_ctx;
12543 if (!event->attr.inherit) {
12544 *inherited_all = 0;
12548 child_ctx = child->perf_event_ctxp[ctxn];
12551 * This is executed from the parent task context, so
12552 * inherit events that have been marked for cloning.
12553 * First allocate and initialize a context for the
12556 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
12560 child->perf_event_ctxp[ctxn] = child_ctx;
12563 ret = inherit_group(event, parent, parent_ctx,
12567 *inherited_all = 0;
12573 * Initialize the perf_event context in task_struct
12575 static int perf_event_init_context(struct task_struct *child, int ctxn)
12577 struct perf_event_context *child_ctx, *parent_ctx;
12578 struct perf_event_context *cloned_ctx;
12579 struct perf_event *event;
12580 struct task_struct *parent = current;
12581 int inherited_all = 1;
12582 unsigned long flags;
12585 if (likely(!parent->perf_event_ctxp[ctxn]))
12589 * If the parent's context is a clone, pin it so it won't get
12590 * swapped under us.
12592 parent_ctx = perf_pin_task_context(parent, ctxn);
12597 * No need to check if parent_ctx != NULL here; since we saw
12598 * it non-NULL earlier, the only reason for it to become NULL
12599 * is if we exit, and since we're currently in the middle of
12600 * a fork we can't be exiting at the same time.
12604 * Lock the parent list. No need to lock the child - not PID
12605 * hashed yet and not running, so nobody can access it.
12607 mutex_lock(&parent_ctx->mutex);
12610 * We dont have to disable NMIs - we are only looking at
12611 * the list, not manipulating it:
12613 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
12614 ret = inherit_task_group(event, parent, parent_ctx,
12615 child, ctxn, &inherited_all);
12621 * We can't hold ctx->lock when iterating the ->flexible_group list due
12622 * to allocations, but we need to prevent rotation because
12623 * rotate_ctx() will change the list from interrupt context.
12625 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12626 parent_ctx->rotate_disable = 1;
12627 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12629 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
12630 ret = inherit_task_group(event, parent, parent_ctx,
12631 child, ctxn, &inherited_all);
12636 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12637 parent_ctx->rotate_disable = 0;
12639 child_ctx = child->perf_event_ctxp[ctxn];
12641 if (child_ctx && inherited_all) {
12643 * Mark the child context as a clone of the parent
12644 * context, or of whatever the parent is a clone of.
12646 * Note that if the parent is a clone, the holding of
12647 * parent_ctx->lock avoids it from being uncloned.
12649 cloned_ctx = parent_ctx->parent_ctx;
12651 child_ctx->parent_ctx = cloned_ctx;
12652 child_ctx->parent_gen = parent_ctx->parent_gen;
12654 child_ctx->parent_ctx = parent_ctx;
12655 child_ctx->parent_gen = parent_ctx->generation;
12657 get_ctx(child_ctx->parent_ctx);
12660 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12662 mutex_unlock(&parent_ctx->mutex);
12664 perf_unpin_context(parent_ctx);
12665 put_ctx(parent_ctx);
12671 * Initialize the perf_event context in task_struct
12673 int perf_event_init_task(struct task_struct *child)
12677 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
12678 mutex_init(&child->perf_event_mutex);
12679 INIT_LIST_HEAD(&child->perf_event_list);
12681 for_each_task_context_nr(ctxn) {
12682 ret = perf_event_init_context(child, ctxn);
12684 perf_event_free_task(child);
12692 static void __init perf_event_init_all_cpus(void)
12694 struct swevent_htable *swhash;
12697 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
12699 for_each_possible_cpu(cpu) {
12700 swhash = &per_cpu(swevent_htable, cpu);
12701 mutex_init(&swhash->hlist_mutex);
12702 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
12704 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
12705 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
12707 #ifdef CONFIG_CGROUP_PERF
12708 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
12710 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
12714 static void perf_swevent_init_cpu(unsigned int cpu)
12716 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
12718 mutex_lock(&swhash->hlist_mutex);
12719 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
12720 struct swevent_hlist *hlist;
12722 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
12724 rcu_assign_pointer(swhash->swevent_hlist, hlist);
12726 mutex_unlock(&swhash->hlist_mutex);
12729 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
12730 static void __perf_event_exit_context(void *__info)
12732 struct perf_event_context *ctx = __info;
12733 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
12734 struct perf_event *event;
12736 raw_spin_lock(&ctx->lock);
12737 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
12738 list_for_each_entry(event, &ctx->event_list, event_entry)
12739 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
12740 raw_spin_unlock(&ctx->lock);
12743 static void perf_event_exit_cpu_context(int cpu)
12745 struct perf_cpu_context *cpuctx;
12746 struct perf_event_context *ctx;
12749 mutex_lock(&pmus_lock);
12750 list_for_each_entry(pmu, &pmus, entry) {
12751 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12752 ctx = &cpuctx->ctx;
12754 mutex_lock(&ctx->mutex);
12755 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
12756 cpuctx->online = 0;
12757 mutex_unlock(&ctx->mutex);
12759 cpumask_clear_cpu(cpu, perf_online_mask);
12760 mutex_unlock(&pmus_lock);
12764 static void perf_event_exit_cpu_context(int cpu) { }
12768 int perf_event_init_cpu(unsigned int cpu)
12770 struct perf_cpu_context *cpuctx;
12771 struct perf_event_context *ctx;
12774 perf_swevent_init_cpu(cpu);
12776 mutex_lock(&pmus_lock);
12777 cpumask_set_cpu(cpu, perf_online_mask);
12778 list_for_each_entry(pmu, &pmus, entry) {
12779 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
12780 ctx = &cpuctx->ctx;
12782 mutex_lock(&ctx->mutex);
12783 cpuctx->online = 1;
12784 mutex_unlock(&ctx->mutex);
12786 mutex_unlock(&pmus_lock);
12791 int perf_event_exit_cpu(unsigned int cpu)
12793 perf_event_exit_cpu_context(cpu);
12798 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
12802 for_each_online_cpu(cpu)
12803 perf_event_exit_cpu(cpu);
12809 * Run the perf reboot notifier at the very last possible moment so that
12810 * the generic watchdog code runs as long as possible.
12812 static struct notifier_block perf_reboot_notifier = {
12813 .notifier_call = perf_reboot,
12814 .priority = INT_MIN,
12817 void __init perf_event_init(void)
12821 idr_init(&pmu_idr);
12823 perf_event_init_all_cpus();
12824 init_srcu_struct(&pmus_srcu);
12825 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
12826 perf_pmu_register(&perf_cpu_clock, NULL, -1);
12827 perf_pmu_register(&perf_task_clock, NULL, -1);
12828 perf_tp_register();
12829 perf_event_init_cpu(smp_processor_id());
12830 register_reboot_notifier(&perf_reboot_notifier);
12832 ret = init_hw_breakpoint();
12833 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
12836 * Build time assertion that we keep the data_head at the intended
12837 * location. IOW, validation we got the __reserved[] size right.
12839 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
12843 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
12846 struct perf_pmu_events_attr *pmu_attr =
12847 container_of(attr, struct perf_pmu_events_attr, attr);
12849 if (pmu_attr->event_str)
12850 return sprintf(page, "%s\n", pmu_attr->event_str);
12854 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
12856 static int __init perf_event_sysfs_init(void)
12861 mutex_lock(&pmus_lock);
12863 ret = bus_register(&pmu_bus);
12867 list_for_each_entry(pmu, &pmus, entry) {
12868 if (!pmu->name || pmu->type < 0)
12871 ret = pmu_dev_alloc(pmu);
12872 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
12874 pmu_bus_running = 1;
12878 mutex_unlock(&pmus_lock);
12882 device_initcall(perf_event_sysfs_init);
12884 #ifdef CONFIG_CGROUP_PERF
12885 static struct cgroup_subsys_state *
12886 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
12888 struct perf_cgroup *jc;
12890 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
12892 return ERR_PTR(-ENOMEM);
12894 jc->info = alloc_percpu(struct perf_cgroup_info);
12897 return ERR_PTR(-ENOMEM);
12903 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
12905 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
12907 free_percpu(jc->info);
12911 static int perf_cgroup_css_online(struct cgroup_subsys_state *css)
12913 perf_event_cgroup(css->cgroup);
12917 static int __perf_cgroup_move(void *info)
12919 struct task_struct *task = info;
12921 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
12926 static void perf_cgroup_attach(struct cgroup_taskset *tset)
12928 struct task_struct *task;
12929 struct cgroup_subsys_state *css;
12931 cgroup_taskset_for_each(task, css, tset)
12932 task_function_call(task, __perf_cgroup_move, task);
12935 struct cgroup_subsys perf_event_cgrp_subsys = {
12936 .css_alloc = perf_cgroup_css_alloc,
12937 .css_free = perf_cgroup_css_free,
12938 .css_online = perf_cgroup_css_online,
12939 .attach = perf_cgroup_attach,
12941 * Implicitly enable on dfl hierarchy so that perf events can
12942 * always be filtered by cgroup2 path as long as perf_event
12943 * controller is not mounted on a legacy hierarchy.
12945 .implicit_on_dfl = true,
12948 #endif /* CONFIG_CGROUP_PERF */