2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/idr.h>
17 #include <linux/file.h>
18 #include <linux/poll.h>
19 #include <linux/slab.h>
20 #include <linux/hash.h>
21 #include <linux/tick.h>
22 #include <linux/sysfs.h>
23 #include <linux/dcache.h>
24 #include <linux/percpu.h>
25 #include <linux/ptrace.h>
26 #include <linux/reboot.h>
27 #include <linux/vmstat.h>
28 #include <linux/device.h>
29 #include <linux/export.h>
30 #include <linux/vmalloc.h>
31 #include <linux/hardirq.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>
56 #include <asm/irq_regs.h>
58 typedef int (*remote_function_f)(void *);
60 struct remote_function_call {
61 struct task_struct *p;
62 remote_function_f func;
67 static void remote_function(void *data)
69 struct remote_function_call *tfc = data;
70 struct task_struct *p = tfc->p;
74 if (task_cpu(p) != smp_processor_id())
78 * Now that we're on right CPU with IRQs disabled, we can test
79 * if we hit the right task without races.
82 tfc->ret = -ESRCH; /* No such (running) process */
87 tfc->ret = tfc->func(tfc->info);
91 * task_function_call - call a function on the cpu on which a task runs
92 * @p: the task to evaluate
93 * @func: the function to be called
94 * @info: the function call argument
96 * Calls the function @func when the task is currently running. This might
97 * be on the current CPU, which just calls the function directly. This will
98 * retry due to any failures in smp_call_function_single(), such as if the
99 * task_cpu() goes offline concurrently.
101 * returns @func return value or -ESRCH or -ENXIO when the process isn't running
104 task_function_call(struct task_struct *p, remote_function_f func, void *info)
106 struct remote_function_call data = {
115 ret = smp_call_function_single(task_cpu(p), remote_function,
130 * cpu_function_call - call a function on the cpu
131 * @func: the function to be called
132 * @info: the function call argument
134 * Calls the function @func on the remote cpu.
136 * returns: @func return value or -ENXIO when the cpu is offline
138 static int cpu_function_call(int cpu, remote_function_f func, void *info)
140 struct remote_function_call data = {
144 .ret = -ENXIO, /* No such CPU */
147 smp_call_function_single(cpu, remote_function, &data, 1);
152 static inline struct perf_cpu_context *
153 __get_cpu_context(struct perf_event_context *ctx)
155 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
158 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
159 struct perf_event_context *ctx)
161 raw_spin_lock(&cpuctx->ctx.lock);
163 raw_spin_lock(&ctx->lock);
166 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
167 struct perf_event_context *ctx)
170 raw_spin_unlock(&ctx->lock);
171 raw_spin_unlock(&cpuctx->ctx.lock);
174 #define TASK_TOMBSTONE ((void *)-1L)
176 static bool is_kernel_event(struct perf_event *event)
178 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
182 * On task ctx scheduling...
184 * When !ctx->nr_events a task context will not be scheduled. This means
185 * we can disable the scheduler hooks (for performance) without leaving
186 * pending task ctx state.
188 * This however results in two special cases:
190 * - removing the last event from a task ctx; this is relatively straight
191 * forward and is done in __perf_remove_from_context.
193 * - adding the first event to a task ctx; this is tricky because we cannot
194 * rely on ctx->is_active and therefore cannot use event_function_call().
195 * See perf_install_in_context().
197 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
200 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
201 struct perf_event_context *, void *);
203 struct event_function_struct {
204 struct perf_event *event;
209 static int event_function(void *info)
211 struct event_function_struct *efs = info;
212 struct perf_event *event = efs->event;
213 struct perf_event_context *ctx = event->ctx;
214 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
215 struct perf_event_context *task_ctx = cpuctx->task_ctx;
218 lockdep_assert_irqs_disabled();
220 perf_ctx_lock(cpuctx, task_ctx);
222 * Since we do the IPI call without holding ctx->lock things can have
223 * changed, double check we hit the task we set out to hit.
226 if (ctx->task != current) {
232 * We only use event_function_call() on established contexts,
233 * and event_function() is only ever called when active (or
234 * rather, we'll have bailed in task_function_call() or the
235 * above ctx->task != current test), therefore we must have
236 * ctx->is_active here.
238 WARN_ON_ONCE(!ctx->is_active);
240 * And since we have ctx->is_active, cpuctx->task_ctx must
243 WARN_ON_ONCE(task_ctx != ctx);
245 WARN_ON_ONCE(&cpuctx->ctx != ctx);
248 efs->func(event, cpuctx, ctx, efs->data);
250 perf_ctx_unlock(cpuctx, task_ctx);
255 static void event_function_call(struct perf_event *event, event_f func, void *data)
257 struct perf_event_context *ctx = event->ctx;
258 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
259 struct event_function_struct efs = {
265 if (!event->parent) {
267 * If this is a !child event, we must hold ctx::mutex to
268 * stabilize the the event->ctx relation. See
269 * perf_event_ctx_lock().
271 lockdep_assert_held(&ctx->mutex);
275 cpu_function_call(event->cpu, event_function, &efs);
279 if (task == TASK_TOMBSTONE)
283 if (!task_function_call(task, event_function, &efs))
286 raw_spin_lock_irq(&ctx->lock);
288 * Reload the task pointer, it might have been changed by
289 * a concurrent perf_event_context_sched_out().
292 if (task == TASK_TOMBSTONE) {
293 raw_spin_unlock_irq(&ctx->lock);
296 if (ctx->is_active) {
297 raw_spin_unlock_irq(&ctx->lock);
300 func(event, NULL, ctx, data);
301 raw_spin_unlock_irq(&ctx->lock);
305 * Similar to event_function_call() + event_function(), but hard assumes IRQs
306 * are already disabled and we're on the right CPU.
308 static void event_function_local(struct perf_event *event, event_f func, void *data)
310 struct perf_event_context *ctx = event->ctx;
311 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
312 struct task_struct *task = READ_ONCE(ctx->task);
313 struct perf_event_context *task_ctx = NULL;
315 lockdep_assert_irqs_disabled();
318 if (task == TASK_TOMBSTONE)
324 perf_ctx_lock(cpuctx, task_ctx);
327 if (task == TASK_TOMBSTONE)
332 * We must be either inactive or active and the right task,
333 * otherwise we're screwed, since we cannot IPI to somewhere
336 if (ctx->is_active) {
337 if (WARN_ON_ONCE(task != current))
340 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
344 WARN_ON_ONCE(&cpuctx->ctx != ctx);
347 func(event, cpuctx, ctx, data);
349 perf_ctx_unlock(cpuctx, task_ctx);
352 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
353 PERF_FLAG_FD_OUTPUT |\
354 PERF_FLAG_PID_CGROUP |\
355 PERF_FLAG_FD_CLOEXEC)
358 * branch priv levels that need permission checks
360 #define PERF_SAMPLE_BRANCH_PERM_PLM \
361 (PERF_SAMPLE_BRANCH_KERNEL |\
362 PERF_SAMPLE_BRANCH_HV)
365 EVENT_FLEXIBLE = 0x1,
368 /* see ctx_resched() for details */
370 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
374 * perf_sched_events : >0 events exist
375 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
378 static void perf_sched_delayed(struct work_struct *work);
379 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
380 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
381 static DEFINE_MUTEX(perf_sched_mutex);
382 static atomic_t perf_sched_count;
384 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
385 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
386 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
388 static atomic_t nr_mmap_events __read_mostly;
389 static atomic_t nr_comm_events __read_mostly;
390 static atomic_t nr_namespaces_events __read_mostly;
391 static atomic_t nr_task_events __read_mostly;
392 static atomic_t nr_freq_events __read_mostly;
393 static atomic_t nr_switch_events __read_mostly;
395 static LIST_HEAD(pmus);
396 static DEFINE_MUTEX(pmus_lock);
397 static struct srcu_struct pmus_srcu;
398 static cpumask_var_t perf_online_mask;
401 * perf event paranoia level:
402 * -1 - not paranoid at all
403 * 0 - disallow raw tracepoint access for unpriv
404 * 1 - disallow cpu events for unpriv
405 * 2 - disallow kernel profiling for unpriv
407 int sysctl_perf_event_paranoid __read_mostly = 2;
409 /* Minimum for 512 kiB + 1 user control page */
410 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
413 * max perf event sample rate
415 #define DEFAULT_MAX_SAMPLE_RATE 100000
416 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
417 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
419 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
421 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
422 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
424 static int perf_sample_allowed_ns __read_mostly =
425 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
427 static void update_perf_cpu_limits(void)
429 u64 tmp = perf_sample_period_ns;
431 tmp *= sysctl_perf_cpu_time_max_percent;
432 tmp = div_u64(tmp, 100);
436 WRITE_ONCE(perf_sample_allowed_ns, tmp);
439 static bool perf_rotate_context(struct perf_cpu_context *cpuctx);
441 int perf_proc_update_handler(struct ctl_table *table, int write,
442 void __user *buffer, size_t *lenp,
446 int perf_cpu = sysctl_perf_cpu_time_max_percent;
448 * If throttling is disabled don't allow the write:
450 if (write && (perf_cpu == 100 || perf_cpu == 0))
453 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
457 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
458 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
459 update_perf_cpu_limits();
464 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
466 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
467 void __user *buffer, size_t *lenp,
470 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
475 if (sysctl_perf_cpu_time_max_percent == 100 ||
476 sysctl_perf_cpu_time_max_percent == 0) {
478 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
479 WRITE_ONCE(perf_sample_allowed_ns, 0);
481 update_perf_cpu_limits();
488 * perf samples are done in some very critical code paths (NMIs).
489 * If they take too much CPU time, the system can lock up and not
490 * get any real work done. This will drop the sample rate when
491 * we detect that events are taking too long.
493 #define NR_ACCUMULATED_SAMPLES 128
494 static DEFINE_PER_CPU(u64, running_sample_length);
496 static u64 __report_avg;
497 static u64 __report_allowed;
499 static void perf_duration_warn(struct irq_work *w)
501 printk_ratelimited(KERN_INFO
502 "perf: interrupt took too long (%lld > %lld), lowering "
503 "kernel.perf_event_max_sample_rate to %d\n",
504 __report_avg, __report_allowed,
505 sysctl_perf_event_sample_rate);
508 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
510 void perf_sample_event_took(u64 sample_len_ns)
512 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
520 /* Decay the counter by 1 average sample. */
521 running_len = __this_cpu_read(running_sample_length);
522 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
523 running_len += sample_len_ns;
524 __this_cpu_write(running_sample_length, running_len);
527 * Note: this will be biased artifically low until we have
528 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
529 * from having to maintain a count.
531 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
532 if (avg_len <= max_len)
535 __report_avg = avg_len;
536 __report_allowed = max_len;
539 * Compute a throttle threshold 25% below the current duration.
541 avg_len += avg_len / 4;
542 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
548 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
549 WRITE_ONCE(max_samples_per_tick, max);
551 sysctl_perf_event_sample_rate = max * HZ;
552 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
554 if (!irq_work_queue(&perf_duration_work)) {
555 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
556 "kernel.perf_event_max_sample_rate to %d\n",
557 __report_avg, __report_allowed,
558 sysctl_perf_event_sample_rate);
562 static atomic64_t perf_event_id;
564 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
565 enum event_type_t event_type);
567 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
568 enum event_type_t event_type,
569 struct task_struct *task);
571 static void update_context_time(struct perf_event_context *ctx);
572 static u64 perf_event_time(struct perf_event *event);
574 void __weak perf_event_print_debug(void) { }
576 extern __weak const char *perf_pmu_name(void)
581 static inline u64 perf_clock(void)
583 return local_clock();
586 static inline u64 perf_event_clock(struct perf_event *event)
588 return event->clock();
592 * State based event timekeeping...
594 * The basic idea is to use event->state to determine which (if any) time
595 * fields to increment with the current delta. This means we only need to
596 * update timestamps when we change state or when they are explicitly requested
599 * Event groups make things a little more complicated, but not terribly so. The
600 * rules for a group are that if the group leader is OFF the entire group is
601 * OFF, irrespecive of what the group member states are. This results in
602 * __perf_effective_state().
604 * A futher ramification is that when a group leader flips between OFF and
605 * !OFF, we need to update all group member times.
608 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
609 * need to make sure the relevant context time is updated before we try and
610 * update our timestamps.
613 static __always_inline enum perf_event_state
614 __perf_effective_state(struct perf_event *event)
616 struct perf_event *leader = event->group_leader;
618 if (leader->state <= PERF_EVENT_STATE_OFF)
619 return leader->state;
624 static __always_inline void
625 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
627 enum perf_event_state state = __perf_effective_state(event);
628 u64 delta = now - event->tstamp;
630 *enabled = event->total_time_enabled;
631 if (state >= PERF_EVENT_STATE_INACTIVE)
634 *running = event->total_time_running;
635 if (state >= PERF_EVENT_STATE_ACTIVE)
639 static void perf_event_update_time(struct perf_event *event)
641 u64 now = perf_event_time(event);
643 __perf_update_times(event, now, &event->total_time_enabled,
644 &event->total_time_running);
648 static void perf_event_update_sibling_time(struct perf_event *leader)
650 struct perf_event *sibling;
652 for_each_sibling_event(sibling, leader)
653 perf_event_update_time(sibling);
657 perf_event_set_state(struct perf_event *event, enum perf_event_state state)
659 if (event->state == state)
662 perf_event_update_time(event);
664 * If a group leader gets enabled/disabled all its siblings
667 if ((event->state < 0) ^ (state < 0))
668 perf_event_update_sibling_time(event);
670 WRITE_ONCE(event->state, state);
673 #ifdef CONFIG_CGROUP_PERF
676 perf_cgroup_match(struct perf_event *event)
678 struct perf_event_context *ctx = event->ctx;
679 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
681 /* @event doesn't care about cgroup */
685 /* wants specific cgroup scope but @cpuctx isn't associated with any */
690 * Cgroup scoping is recursive. An event enabled for a cgroup is
691 * also enabled for all its descendant cgroups. If @cpuctx's
692 * cgroup is a descendant of @event's (the test covers identity
693 * case), it's a match.
695 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
696 event->cgrp->css.cgroup);
699 static inline void perf_detach_cgroup(struct perf_event *event)
701 css_put(&event->cgrp->css);
705 static inline int is_cgroup_event(struct perf_event *event)
707 return event->cgrp != NULL;
710 static inline u64 perf_cgroup_event_time(struct perf_event *event)
712 struct perf_cgroup_info *t;
714 t = per_cpu_ptr(event->cgrp->info, event->cpu);
718 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
720 struct perf_cgroup_info *info;
725 info = this_cpu_ptr(cgrp->info);
727 info->time += now - info->timestamp;
728 info->timestamp = now;
731 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
733 struct perf_cgroup *cgrp = cpuctx->cgrp;
734 struct cgroup_subsys_state *css;
737 for (css = &cgrp->css; css; css = css->parent) {
738 cgrp = container_of(css, struct perf_cgroup, css);
739 __update_cgrp_time(cgrp);
744 static inline void update_cgrp_time_from_event(struct perf_event *event)
746 struct perf_cgroup *cgrp;
749 * ensure we access cgroup data only when needed and
750 * when we know the cgroup is pinned (css_get)
752 if (!is_cgroup_event(event))
755 cgrp = perf_cgroup_from_task(current, event->ctx);
757 * Do not update time when cgroup is not active
759 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
760 __update_cgrp_time(event->cgrp);
764 perf_cgroup_set_timestamp(struct task_struct *task,
765 struct perf_event_context *ctx)
767 struct perf_cgroup *cgrp;
768 struct perf_cgroup_info *info;
769 struct cgroup_subsys_state *css;
772 * ctx->lock held by caller
773 * ensure we do not access cgroup data
774 * unless we have the cgroup pinned (css_get)
776 if (!task || !ctx->nr_cgroups)
779 cgrp = perf_cgroup_from_task(task, ctx);
781 for (css = &cgrp->css; css; css = css->parent) {
782 cgrp = container_of(css, struct perf_cgroup, css);
783 info = this_cpu_ptr(cgrp->info);
784 info->timestamp = ctx->timestamp;
788 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
790 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
791 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
794 * reschedule events based on the cgroup constraint of task.
796 * mode SWOUT : schedule out everything
797 * mode SWIN : schedule in based on cgroup for next
799 static void perf_cgroup_switch(struct task_struct *task, int mode)
801 struct perf_cpu_context *cpuctx, *tmp;
802 struct list_head *list;
806 * Disable interrupts and preemption to avoid this CPU's
807 * cgrp_cpuctx_entry to change under us.
809 local_irq_save(flags);
811 list = this_cpu_ptr(&cgrp_cpuctx_list);
812 list_for_each_entry_safe(cpuctx, tmp, list, cgrp_cpuctx_entry) {
813 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
815 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
816 perf_pmu_disable(cpuctx->ctx.pmu);
818 if (mode & PERF_CGROUP_SWOUT) {
819 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
821 * must not be done before ctxswout due
822 * to event_filter_match() in event_sched_out()
827 if (mode & PERF_CGROUP_SWIN) {
828 WARN_ON_ONCE(cpuctx->cgrp);
830 * set cgrp before ctxsw in to allow
831 * event_filter_match() to not have to pass
833 * we pass the cpuctx->ctx to perf_cgroup_from_task()
834 * because cgorup events are only per-cpu
836 cpuctx->cgrp = perf_cgroup_from_task(task,
838 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
840 perf_pmu_enable(cpuctx->ctx.pmu);
841 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
844 local_irq_restore(flags);
847 static inline void perf_cgroup_sched_out(struct task_struct *task,
848 struct task_struct *next)
850 struct perf_cgroup *cgrp1;
851 struct perf_cgroup *cgrp2 = NULL;
855 * we come here when we know perf_cgroup_events > 0
856 * we do not need to pass the ctx here because we know
857 * we are holding the rcu lock
859 cgrp1 = perf_cgroup_from_task(task, NULL);
860 cgrp2 = perf_cgroup_from_task(next, NULL);
863 * only schedule out current cgroup events if we know
864 * that we are switching to a different cgroup. Otherwise,
865 * do no touch the cgroup events.
868 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
873 static inline void perf_cgroup_sched_in(struct task_struct *prev,
874 struct task_struct *task)
876 struct perf_cgroup *cgrp1;
877 struct perf_cgroup *cgrp2 = NULL;
881 * we come here when we know perf_cgroup_events > 0
882 * we do not need to pass the ctx here because we know
883 * we are holding the rcu lock
885 cgrp1 = perf_cgroup_from_task(task, NULL);
886 cgrp2 = perf_cgroup_from_task(prev, NULL);
889 * only need to schedule in cgroup events if we are changing
890 * cgroup during ctxsw. Cgroup events were not scheduled
891 * out of ctxsw out if that was not the case.
894 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
899 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
900 struct perf_event_attr *attr,
901 struct perf_event *group_leader)
903 struct perf_cgroup *cgrp;
904 struct cgroup_subsys_state *css;
905 struct fd f = fdget(fd);
911 css = css_tryget_online_from_dir(f.file->f_path.dentry,
912 &perf_event_cgrp_subsys);
918 cgrp = container_of(css, struct perf_cgroup, css);
922 * all events in a group must monitor
923 * the same cgroup because a task belongs
924 * to only one perf cgroup at a time
926 if (group_leader && group_leader->cgrp != cgrp) {
927 perf_detach_cgroup(event);
936 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
938 struct perf_cgroup_info *t;
939 t = per_cpu_ptr(event->cgrp->info, event->cpu);
940 event->shadow_ctx_time = now - t->timestamp;
944 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
945 * cleared when last cgroup event is removed.
948 list_update_cgroup_event(struct perf_event *event,
949 struct perf_event_context *ctx, bool add)
951 struct perf_cpu_context *cpuctx;
952 struct list_head *cpuctx_entry;
954 if (!is_cgroup_event(event))
958 * Because cgroup events are always per-cpu events,
959 * this will always be called from the right CPU.
961 cpuctx = __get_cpu_context(ctx);
964 * Since setting cpuctx->cgrp is conditional on the current @cgrp
965 * matching the event's cgroup, we must do this for every new event,
966 * because if the first would mismatch, the second would not try again
967 * and we would leave cpuctx->cgrp unset.
969 if (add && !cpuctx->cgrp) {
970 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
972 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
976 if (add && ctx->nr_cgroups++)
978 else if (!add && --ctx->nr_cgroups)
981 /* no cgroup running */
985 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
987 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
989 list_del(cpuctx_entry);
992 #else /* !CONFIG_CGROUP_PERF */
995 perf_cgroup_match(struct perf_event *event)
1000 static inline void perf_detach_cgroup(struct perf_event *event)
1003 static inline int is_cgroup_event(struct perf_event *event)
1008 static inline void update_cgrp_time_from_event(struct perf_event *event)
1012 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
1016 static inline void perf_cgroup_sched_out(struct task_struct *task,
1017 struct task_struct *next)
1021 static inline void perf_cgroup_sched_in(struct task_struct *prev,
1022 struct task_struct *task)
1026 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1027 struct perf_event_attr *attr,
1028 struct perf_event *group_leader)
1034 perf_cgroup_set_timestamp(struct task_struct *task,
1035 struct perf_event_context *ctx)
1040 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1045 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1049 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1055 list_update_cgroup_event(struct perf_event *event,
1056 struct perf_event_context *ctx, bool add)
1063 * set default to be dependent on timer tick just
1064 * like original code
1066 #define PERF_CPU_HRTIMER (1000 / HZ)
1068 * function must be called with interrupts disabled
1070 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1072 struct perf_cpu_context *cpuctx;
1075 lockdep_assert_irqs_disabled();
1077 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1078 rotations = perf_rotate_context(cpuctx);
1080 raw_spin_lock(&cpuctx->hrtimer_lock);
1082 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1084 cpuctx->hrtimer_active = 0;
1085 raw_spin_unlock(&cpuctx->hrtimer_lock);
1087 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1090 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1092 struct hrtimer *timer = &cpuctx->hrtimer;
1093 struct pmu *pmu = cpuctx->ctx.pmu;
1096 /* no multiplexing needed for SW PMU */
1097 if (pmu->task_ctx_nr == perf_sw_context)
1101 * check default is sane, if not set then force to
1102 * default interval (1/tick)
1104 interval = pmu->hrtimer_interval_ms;
1106 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1108 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1110 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1111 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1112 timer->function = perf_mux_hrtimer_handler;
1115 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1117 struct hrtimer *timer = &cpuctx->hrtimer;
1118 struct pmu *pmu = cpuctx->ctx.pmu;
1119 unsigned long flags;
1121 /* not for SW PMU */
1122 if (pmu->task_ctx_nr == perf_sw_context)
1125 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1126 if (!cpuctx->hrtimer_active) {
1127 cpuctx->hrtimer_active = 1;
1128 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1129 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
1131 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1136 void perf_pmu_disable(struct pmu *pmu)
1138 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1140 pmu->pmu_disable(pmu);
1143 void perf_pmu_enable(struct pmu *pmu)
1145 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1147 pmu->pmu_enable(pmu);
1150 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1153 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1154 * perf_event_task_tick() are fully serialized because they're strictly cpu
1155 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1156 * disabled, while perf_event_task_tick is called from IRQ context.
1158 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1160 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1162 lockdep_assert_irqs_disabled();
1164 WARN_ON(!list_empty(&ctx->active_ctx_list));
1166 list_add(&ctx->active_ctx_list, head);
1169 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1171 lockdep_assert_irqs_disabled();
1173 WARN_ON(list_empty(&ctx->active_ctx_list));
1175 list_del_init(&ctx->active_ctx_list);
1178 static void get_ctx(struct perf_event_context *ctx)
1180 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1183 static void free_ctx(struct rcu_head *head)
1185 struct perf_event_context *ctx;
1187 ctx = container_of(head, struct perf_event_context, rcu_head);
1188 kfree(ctx->task_ctx_data);
1192 static void put_ctx(struct perf_event_context *ctx)
1194 if (atomic_dec_and_test(&ctx->refcount)) {
1195 if (ctx->parent_ctx)
1196 put_ctx(ctx->parent_ctx);
1197 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1198 put_task_struct(ctx->task);
1199 call_rcu(&ctx->rcu_head, free_ctx);
1204 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1205 * perf_pmu_migrate_context() we need some magic.
1207 * Those places that change perf_event::ctx will hold both
1208 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1210 * Lock ordering is by mutex address. There are two other sites where
1211 * perf_event_context::mutex nests and those are:
1213 * - perf_event_exit_task_context() [ child , 0 ]
1214 * perf_event_exit_event()
1215 * put_event() [ parent, 1 ]
1217 * - perf_event_init_context() [ parent, 0 ]
1218 * inherit_task_group()
1221 * perf_event_alloc()
1223 * perf_try_init_event() [ child , 1 ]
1225 * While it appears there is an obvious deadlock here -- the parent and child
1226 * nesting levels are inverted between the two. This is in fact safe because
1227 * life-time rules separate them. That is an exiting task cannot fork, and a
1228 * spawning task cannot (yet) exit.
1230 * But remember that that these are parent<->child context relations, and
1231 * migration does not affect children, therefore these two orderings should not
1234 * The change in perf_event::ctx does not affect children (as claimed above)
1235 * because the sys_perf_event_open() case will install a new event and break
1236 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1237 * concerned with cpuctx and that doesn't have children.
1239 * The places that change perf_event::ctx will issue:
1241 * perf_remove_from_context();
1242 * synchronize_rcu();
1243 * perf_install_in_context();
1245 * to affect the change. The remove_from_context() + synchronize_rcu() should
1246 * quiesce the event, after which we can install it in the new location. This
1247 * means that only external vectors (perf_fops, prctl) can perturb the event
1248 * while in transit. Therefore all such accessors should also acquire
1249 * perf_event_context::mutex to serialize against this.
1251 * However; because event->ctx can change while we're waiting to acquire
1252 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1257 * task_struct::perf_event_mutex
1258 * perf_event_context::mutex
1259 * perf_event::child_mutex;
1260 * perf_event_context::lock
1261 * perf_event::mmap_mutex
1263 * perf_addr_filters_head::lock
1267 * cpuctx->mutex / perf_event_context::mutex
1269 static struct perf_event_context *
1270 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1272 struct perf_event_context *ctx;
1276 ctx = READ_ONCE(event->ctx);
1277 if (!atomic_inc_not_zero(&ctx->refcount)) {
1283 mutex_lock_nested(&ctx->mutex, nesting);
1284 if (event->ctx != ctx) {
1285 mutex_unlock(&ctx->mutex);
1293 static inline struct perf_event_context *
1294 perf_event_ctx_lock(struct perf_event *event)
1296 return perf_event_ctx_lock_nested(event, 0);
1299 static void perf_event_ctx_unlock(struct perf_event *event,
1300 struct perf_event_context *ctx)
1302 mutex_unlock(&ctx->mutex);
1307 * This must be done under the ctx->lock, such as to serialize against
1308 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1309 * calling scheduler related locks and ctx->lock nests inside those.
1311 static __must_check struct perf_event_context *
1312 unclone_ctx(struct perf_event_context *ctx)
1314 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1316 lockdep_assert_held(&ctx->lock);
1319 ctx->parent_ctx = NULL;
1325 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1330 * only top level events have the pid namespace they were created in
1333 event = event->parent;
1335 nr = __task_pid_nr_ns(p, type, event->ns);
1336 /* avoid -1 if it is idle thread or runs in another ns */
1337 if (!nr && !pid_alive(p))
1342 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1344 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1347 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1349 return perf_event_pid_type(event, p, PIDTYPE_PID);
1353 * If we inherit events we want to return the parent event id
1356 static u64 primary_event_id(struct perf_event *event)
1361 id = event->parent->id;
1367 * Get the perf_event_context for a task and lock it.
1369 * This has to cope with with the fact that until it is locked,
1370 * the context could get moved to another task.
1372 static struct perf_event_context *
1373 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1375 struct perf_event_context *ctx;
1379 * One of the few rules of preemptible RCU is that one cannot do
1380 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1381 * part of the read side critical section was irqs-enabled -- see
1382 * rcu_read_unlock_special().
1384 * Since ctx->lock nests under rq->lock we must ensure the entire read
1385 * side critical section has interrupts disabled.
1387 local_irq_save(*flags);
1389 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1392 * If this context is a clone of another, it might
1393 * get swapped for another underneath us by
1394 * perf_event_task_sched_out, though the
1395 * rcu_read_lock() protects us from any context
1396 * getting freed. Lock the context and check if it
1397 * got swapped before we could get the lock, and retry
1398 * if so. If we locked the right context, then it
1399 * can't get swapped on us any more.
1401 raw_spin_lock(&ctx->lock);
1402 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1403 raw_spin_unlock(&ctx->lock);
1405 local_irq_restore(*flags);
1409 if (ctx->task == TASK_TOMBSTONE ||
1410 !atomic_inc_not_zero(&ctx->refcount)) {
1411 raw_spin_unlock(&ctx->lock);
1414 WARN_ON_ONCE(ctx->task != task);
1419 local_irq_restore(*flags);
1424 * Get the context for a task and increment its pin_count so it
1425 * can't get swapped to another task. This also increments its
1426 * reference count so that the context can't get freed.
1428 static struct perf_event_context *
1429 perf_pin_task_context(struct task_struct *task, int ctxn)
1431 struct perf_event_context *ctx;
1432 unsigned long flags;
1434 ctx = perf_lock_task_context(task, ctxn, &flags);
1437 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1442 static void perf_unpin_context(struct perf_event_context *ctx)
1444 unsigned long flags;
1446 raw_spin_lock_irqsave(&ctx->lock, flags);
1448 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1452 * Update the record of the current time in a context.
1454 static void update_context_time(struct perf_event_context *ctx)
1456 u64 now = perf_clock();
1458 ctx->time += now - ctx->timestamp;
1459 ctx->timestamp = now;
1462 static u64 perf_event_time(struct perf_event *event)
1464 struct perf_event_context *ctx = event->ctx;
1466 if (is_cgroup_event(event))
1467 return perf_cgroup_event_time(event);
1469 return ctx ? ctx->time : 0;
1472 static enum event_type_t get_event_type(struct perf_event *event)
1474 struct perf_event_context *ctx = event->ctx;
1475 enum event_type_t event_type;
1477 lockdep_assert_held(&ctx->lock);
1480 * It's 'group type', really, because if our group leader is
1481 * pinned, so are we.
1483 if (event->group_leader != event)
1484 event = event->group_leader;
1486 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1488 event_type |= EVENT_CPU;
1494 * Helper function to initialize event group nodes.
1496 static void init_event_group(struct perf_event *event)
1498 RB_CLEAR_NODE(&event->group_node);
1499 event->group_index = 0;
1503 * Extract pinned or flexible groups from the context
1504 * based on event attrs bits.
1506 static struct perf_event_groups *
1507 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1509 if (event->attr.pinned)
1510 return &ctx->pinned_groups;
1512 return &ctx->flexible_groups;
1516 * Helper function to initializes perf_event_group trees.
1518 static void perf_event_groups_init(struct perf_event_groups *groups)
1520 groups->tree = RB_ROOT;
1525 * Compare function for event groups;
1527 * Implements complex key that first sorts by CPU and then by virtual index
1528 * which provides ordering when rotating groups for the same CPU.
1531 perf_event_groups_less(struct perf_event *left, struct perf_event *right)
1533 if (left->cpu < right->cpu)
1535 if (left->cpu > right->cpu)
1538 if (left->group_index < right->group_index)
1540 if (left->group_index > right->group_index)
1547 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1548 * key (see perf_event_groups_less). This places it last inside the CPU
1552 perf_event_groups_insert(struct perf_event_groups *groups,
1553 struct perf_event *event)
1555 struct perf_event *node_event;
1556 struct rb_node *parent;
1557 struct rb_node **node;
1559 event->group_index = ++groups->index;
1561 node = &groups->tree.rb_node;
1566 node_event = container_of(*node, struct perf_event, group_node);
1568 if (perf_event_groups_less(event, node_event))
1569 node = &parent->rb_left;
1571 node = &parent->rb_right;
1574 rb_link_node(&event->group_node, parent, node);
1575 rb_insert_color(&event->group_node, &groups->tree);
1579 * Helper function to insert event into the pinned or flexible groups.
1582 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1584 struct perf_event_groups *groups;
1586 groups = get_event_groups(event, ctx);
1587 perf_event_groups_insert(groups, event);
1591 * Delete a group from a tree.
1594 perf_event_groups_delete(struct perf_event_groups *groups,
1595 struct perf_event *event)
1597 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1598 RB_EMPTY_ROOT(&groups->tree));
1600 rb_erase(&event->group_node, &groups->tree);
1601 init_event_group(event);
1605 * Helper function to delete event from its groups.
1608 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1610 struct perf_event_groups *groups;
1612 groups = get_event_groups(event, ctx);
1613 perf_event_groups_delete(groups, event);
1617 * Get the leftmost event in the @cpu subtree.
1619 static struct perf_event *
1620 perf_event_groups_first(struct perf_event_groups *groups, int cpu)
1622 struct perf_event *node_event = NULL, *match = NULL;
1623 struct rb_node *node = groups->tree.rb_node;
1626 node_event = container_of(node, struct perf_event, group_node);
1628 if (cpu < node_event->cpu) {
1629 node = node->rb_left;
1630 } else if (cpu > node_event->cpu) {
1631 node = node->rb_right;
1634 node = node->rb_left;
1642 * Like rb_entry_next_safe() for the @cpu subtree.
1644 static struct perf_event *
1645 perf_event_groups_next(struct perf_event *event)
1647 struct perf_event *next;
1649 next = rb_entry_safe(rb_next(&event->group_node), typeof(*event), group_node);
1650 if (next && next->cpu == event->cpu)
1657 * Iterate through the whole groups tree.
1659 #define perf_event_groups_for_each(event, groups) \
1660 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1661 typeof(*event), group_node); event; \
1662 event = rb_entry_safe(rb_next(&event->group_node), \
1663 typeof(*event), group_node))
1666 * Add an event from the lists for its context.
1667 * Must be called with ctx->mutex and ctx->lock held.
1670 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1672 lockdep_assert_held(&ctx->lock);
1674 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1675 event->attach_state |= PERF_ATTACH_CONTEXT;
1677 event->tstamp = perf_event_time(event);
1680 * If we're a stand alone event or group leader, we go to the context
1681 * list, group events are kept attached to the group so that
1682 * perf_group_detach can, at all times, locate all siblings.
1684 if (event->group_leader == event) {
1685 event->group_caps = event->event_caps;
1686 add_event_to_groups(event, ctx);
1689 list_update_cgroup_event(event, ctx, true);
1691 list_add_rcu(&event->event_entry, &ctx->event_list);
1693 if (event->attr.inherit_stat)
1700 * Initialize event state based on the perf_event_attr::disabled.
1702 static inline void perf_event__state_init(struct perf_event *event)
1704 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1705 PERF_EVENT_STATE_INACTIVE;
1708 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1710 int entry = sizeof(u64); /* value */
1714 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1715 size += sizeof(u64);
1717 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1718 size += sizeof(u64);
1720 if (event->attr.read_format & PERF_FORMAT_ID)
1721 entry += sizeof(u64);
1723 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1725 size += sizeof(u64);
1729 event->read_size = size;
1732 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1734 struct perf_sample_data *data;
1737 if (sample_type & PERF_SAMPLE_IP)
1738 size += sizeof(data->ip);
1740 if (sample_type & PERF_SAMPLE_ADDR)
1741 size += sizeof(data->addr);
1743 if (sample_type & PERF_SAMPLE_PERIOD)
1744 size += sizeof(data->period);
1746 if (sample_type & PERF_SAMPLE_WEIGHT)
1747 size += sizeof(data->weight);
1749 if (sample_type & PERF_SAMPLE_READ)
1750 size += event->read_size;
1752 if (sample_type & PERF_SAMPLE_DATA_SRC)
1753 size += sizeof(data->data_src.val);
1755 if (sample_type & PERF_SAMPLE_TRANSACTION)
1756 size += sizeof(data->txn);
1758 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1759 size += sizeof(data->phys_addr);
1761 event->header_size = size;
1765 * Called at perf_event creation and when events are attached/detached from a
1768 static void perf_event__header_size(struct perf_event *event)
1770 __perf_event_read_size(event,
1771 event->group_leader->nr_siblings);
1772 __perf_event_header_size(event, event->attr.sample_type);
1775 static void perf_event__id_header_size(struct perf_event *event)
1777 struct perf_sample_data *data;
1778 u64 sample_type = event->attr.sample_type;
1781 if (sample_type & PERF_SAMPLE_TID)
1782 size += sizeof(data->tid_entry);
1784 if (sample_type & PERF_SAMPLE_TIME)
1785 size += sizeof(data->time);
1787 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1788 size += sizeof(data->id);
1790 if (sample_type & PERF_SAMPLE_ID)
1791 size += sizeof(data->id);
1793 if (sample_type & PERF_SAMPLE_STREAM_ID)
1794 size += sizeof(data->stream_id);
1796 if (sample_type & PERF_SAMPLE_CPU)
1797 size += sizeof(data->cpu_entry);
1799 event->id_header_size = size;
1802 static bool perf_event_validate_size(struct perf_event *event)
1805 * The values computed here will be over-written when we actually
1808 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1809 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1810 perf_event__id_header_size(event);
1813 * Sum the lot; should not exceed the 64k limit we have on records.
1814 * Conservative limit to allow for callchains and other variable fields.
1816 if (event->read_size + event->header_size +
1817 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1823 static void perf_group_attach(struct perf_event *event)
1825 struct perf_event *group_leader = event->group_leader, *pos;
1827 lockdep_assert_held(&event->ctx->lock);
1830 * We can have double attach due to group movement in perf_event_open.
1832 if (event->attach_state & PERF_ATTACH_GROUP)
1835 event->attach_state |= PERF_ATTACH_GROUP;
1837 if (group_leader == event)
1840 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1842 group_leader->group_caps &= event->event_caps;
1844 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1845 group_leader->nr_siblings++;
1847 perf_event__header_size(group_leader);
1849 for_each_sibling_event(pos, group_leader)
1850 perf_event__header_size(pos);
1854 * Remove an event from the lists for its context.
1855 * Must be called with ctx->mutex and ctx->lock held.
1858 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1860 WARN_ON_ONCE(event->ctx != ctx);
1861 lockdep_assert_held(&ctx->lock);
1864 * We can have double detach due to exit/hot-unplug + close.
1866 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1869 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1871 list_update_cgroup_event(event, ctx, false);
1874 if (event->attr.inherit_stat)
1877 list_del_rcu(&event->event_entry);
1879 if (event->group_leader == event)
1880 del_event_from_groups(event, ctx);
1883 * If event was in error state, then keep it
1884 * that way, otherwise bogus counts will be
1885 * returned on read(). The only way to get out
1886 * of error state is by explicit re-enabling
1889 if (event->state > PERF_EVENT_STATE_OFF)
1890 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1895 static void perf_group_detach(struct perf_event *event)
1897 struct perf_event *sibling, *tmp;
1898 struct perf_event_context *ctx = event->ctx;
1900 lockdep_assert_held(&ctx->lock);
1903 * We can have double detach due to exit/hot-unplug + close.
1905 if (!(event->attach_state & PERF_ATTACH_GROUP))
1908 event->attach_state &= ~PERF_ATTACH_GROUP;
1911 * If this is a sibling, remove it from its group.
1913 if (event->group_leader != event) {
1914 list_del_init(&event->sibling_list);
1915 event->group_leader->nr_siblings--;
1920 * If this was a group event with sibling events then
1921 * upgrade the siblings to singleton events by adding them
1922 * to whatever list we are on.
1924 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
1926 sibling->group_leader = sibling;
1927 list_del_init(&sibling->sibling_list);
1929 /* Inherit group flags from the previous leader */
1930 sibling->group_caps = event->group_caps;
1932 if (!RB_EMPTY_NODE(&event->group_node)) {
1933 add_event_to_groups(sibling, event->ctx);
1935 if (sibling->state == PERF_EVENT_STATE_ACTIVE) {
1936 struct list_head *list = sibling->attr.pinned ?
1937 &ctx->pinned_active : &ctx->flexible_active;
1939 list_add_tail(&sibling->active_list, list);
1943 WARN_ON_ONCE(sibling->ctx != event->ctx);
1947 perf_event__header_size(event->group_leader);
1949 for_each_sibling_event(tmp, event->group_leader)
1950 perf_event__header_size(tmp);
1953 static bool is_orphaned_event(struct perf_event *event)
1955 return event->state == PERF_EVENT_STATE_DEAD;
1958 static inline int __pmu_filter_match(struct perf_event *event)
1960 struct pmu *pmu = event->pmu;
1961 return pmu->filter_match ? pmu->filter_match(event) : 1;
1965 * Check whether we should attempt to schedule an event group based on
1966 * PMU-specific filtering. An event group can consist of HW and SW events,
1967 * potentially with a SW leader, so we must check all the filters, to
1968 * determine whether a group is schedulable:
1970 static inline int pmu_filter_match(struct perf_event *event)
1972 struct perf_event *sibling;
1974 if (!__pmu_filter_match(event))
1977 for_each_sibling_event(sibling, event) {
1978 if (!__pmu_filter_match(sibling))
1986 event_filter_match(struct perf_event *event)
1988 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1989 perf_cgroup_match(event) && pmu_filter_match(event);
1993 event_sched_out(struct perf_event *event,
1994 struct perf_cpu_context *cpuctx,
1995 struct perf_event_context *ctx)
1997 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
1999 WARN_ON_ONCE(event->ctx != ctx);
2000 lockdep_assert_held(&ctx->lock);
2002 if (event->state != PERF_EVENT_STATE_ACTIVE)
2006 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2007 * we can schedule events _OUT_ individually through things like
2008 * __perf_remove_from_context().
2010 list_del_init(&event->active_list);
2012 perf_pmu_disable(event->pmu);
2014 event->pmu->del(event, 0);
2017 if (READ_ONCE(event->pending_disable) >= 0) {
2018 WRITE_ONCE(event->pending_disable, -1);
2019 state = PERF_EVENT_STATE_OFF;
2021 perf_event_set_state(event, state);
2023 if (!is_software_event(event))
2024 cpuctx->active_oncpu--;
2025 if (!--ctx->nr_active)
2026 perf_event_ctx_deactivate(ctx);
2027 if (event->attr.freq && event->attr.sample_freq)
2029 if (event->attr.exclusive || !cpuctx->active_oncpu)
2030 cpuctx->exclusive = 0;
2032 perf_pmu_enable(event->pmu);
2036 group_sched_out(struct perf_event *group_event,
2037 struct perf_cpu_context *cpuctx,
2038 struct perf_event_context *ctx)
2040 struct perf_event *event;
2042 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2045 perf_pmu_disable(ctx->pmu);
2047 event_sched_out(group_event, cpuctx, ctx);
2050 * Schedule out siblings (if any):
2052 for_each_sibling_event(event, group_event)
2053 event_sched_out(event, cpuctx, ctx);
2055 perf_pmu_enable(ctx->pmu);
2057 if (group_event->attr.exclusive)
2058 cpuctx->exclusive = 0;
2061 #define DETACH_GROUP 0x01UL
2064 * Cross CPU call to remove a performance event
2066 * We disable the event on the hardware level first. After that we
2067 * remove it from the context list.
2070 __perf_remove_from_context(struct perf_event *event,
2071 struct perf_cpu_context *cpuctx,
2072 struct perf_event_context *ctx,
2075 unsigned long flags = (unsigned long)info;
2077 if (ctx->is_active & EVENT_TIME) {
2078 update_context_time(ctx);
2079 update_cgrp_time_from_cpuctx(cpuctx);
2082 event_sched_out(event, cpuctx, ctx);
2083 if (flags & DETACH_GROUP)
2084 perf_group_detach(event);
2085 list_del_event(event, ctx);
2087 if (!ctx->nr_events && ctx->is_active) {
2089 ctx->rotate_necessary = 0;
2091 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2092 cpuctx->task_ctx = NULL;
2098 * Remove the event from a task's (or a CPU's) list of events.
2100 * If event->ctx is a cloned context, callers must make sure that
2101 * every task struct that event->ctx->task could possibly point to
2102 * remains valid. This is OK when called from perf_release since
2103 * that only calls us on the top-level context, which can't be a clone.
2104 * When called from perf_event_exit_task, it's OK because the
2105 * context has been detached from its task.
2107 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2109 struct perf_event_context *ctx = event->ctx;
2111 lockdep_assert_held(&ctx->mutex);
2113 event_function_call(event, __perf_remove_from_context, (void *)flags);
2116 * The above event_function_call() can NO-OP when it hits
2117 * TASK_TOMBSTONE. In that case we must already have been detached
2118 * from the context (by perf_event_exit_event()) but the grouping
2119 * might still be in-tact.
2121 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
2122 if ((flags & DETACH_GROUP) &&
2123 (event->attach_state & PERF_ATTACH_GROUP)) {
2125 * Since in that case we cannot possibly be scheduled, simply
2128 raw_spin_lock_irq(&ctx->lock);
2129 perf_group_detach(event);
2130 raw_spin_unlock_irq(&ctx->lock);
2135 * Cross CPU call to disable a performance event
2137 static void __perf_event_disable(struct perf_event *event,
2138 struct perf_cpu_context *cpuctx,
2139 struct perf_event_context *ctx,
2142 if (event->state < PERF_EVENT_STATE_INACTIVE)
2145 if (ctx->is_active & EVENT_TIME) {
2146 update_context_time(ctx);
2147 update_cgrp_time_from_event(event);
2150 if (event == event->group_leader)
2151 group_sched_out(event, cpuctx, ctx);
2153 event_sched_out(event, cpuctx, ctx);
2155 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2161 * If event->ctx is a cloned context, callers must make sure that
2162 * every task struct that event->ctx->task could possibly point to
2163 * remains valid. This condition is satisifed when called through
2164 * perf_event_for_each_child or perf_event_for_each because they
2165 * hold the top-level event's child_mutex, so any descendant that
2166 * goes to exit will block in perf_event_exit_event().
2168 * When called from perf_pending_event it's OK because event->ctx
2169 * is the current context on this CPU and preemption is disabled,
2170 * hence we can't get into perf_event_task_sched_out for this context.
2172 static void _perf_event_disable(struct perf_event *event)
2174 struct perf_event_context *ctx = event->ctx;
2176 raw_spin_lock_irq(&ctx->lock);
2177 if (event->state <= PERF_EVENT_STATE_OFF) {
2178 raw_spin_unlock_irq(&ctx->lock);
2181 raw_spin_unlock_irq(&ctx->lock);
2183 event_function_call(event, __perf_event_disable, NULL);
2186 void perf_event_disable_local(struct perf_event *event)
2188 event_function_local(event, __perf_event_disable, NULL);
2192 * Strictly speaking kernel users cannot create groups and therefore this
2193 * interface does not need the perf_event_ctx_lock() magic.
2195 void perf_event_disable(struct perf_event *event)
2197 struct perf_event_context *ctx;
2199 ctx = perf_event_ctx_lock(event);
2200 _perf_event_disable(event);
2201 perf_event_ctx_unlock(event, ctx);
2203 EXPORT_SYMBOL_GPL(perf_event_disable);
2205 void perf_event_disable_inatomic(struct perf_event *event)
2207 WRITE_ONCE(event->pending_disable, smp_processor_id());
2208 /* can fail, see perf_pending_event_disable() */
2209 irq_work_queue(&event->pending);
2212 static void perf_set_shadow_time(struct perf_event *event,
2213 struct perf_event_context *ctx)
2216 * use the correct time source for the time snapshot
2218 * We could get by without this by leveraging the
2219 * fact that to get to this function, the caller
2220 * has most likely already called update_context_time()
2221 * and update_cgrp_time_xx() and thus both timestamp
2222 * are identical (or very close). Given that tstamp is,
2223 * already adjusted for cgroup, we could say that:
2224 * tstamp - ctx->timestamp
2226 * tstamp - cgrp->timestamp.
2228 * Then, in perf_output_read(), the calculation would
2229 * work with no changes because:
2230 * - event is guaranteed scheduled in
2231 * - no scheduled out in between
2232 * - thus the timestamp would be the same
2234 * But this is a bit hairy.
2236 * So instead, we have an explicit cgroup call to remain
2237 * within the time time source all along. We believe it
2238 * is cleaner and simpler to understand.
2240 if (is_cgroup_event(event))
2241 perf_cgroup_set_shadow_time(event, event->tstamp);
2243 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2246 #define MAX_INTERRUPTS (~0ULL)
2248 static void perf_log_throttle(struct perf_event *event, int enable);
2249 static void perf_log_itrace_start(struct perf_event *event);
2252 event_sched_in(struct perf_event *event,
2253 struct perf_cpu_context *cpuctx,
2254 struct perf_event_context *ctx)
2258 lockdep_assert_held(&ctx->lock);
2260 if (event->state <= PERF_EVENT_STATE_OFF)
2263 WRITE_ONCE(event->oncpu, smp_processor_id());
2265 * Order event::oncpu write to happen before the ACTIVE state is
2266 * visible. This allows perf_event_{stop,read}() to observe the correct
2267 * ->oncpu if it sees ACTIVE.
2270 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2273 * Unthrottle events, since we scheduled we might have missed several
2274 * ticks already, also for a heavily scheduling task there is little
2275 * guarantee it'll get a tick in a timely manner.
2277 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2278 perf_log_throttle(event, 1);
2279 event->hw.interrupts = 0;
2282 perf_pmu_disable(event->pmu);
2284 perf_set_shadow_time(event, ctx);
2286 perf_log_itrace_start(event);
2288 if (event->pmu->add(event, PERF_EF_START)) {
2289 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2295 if (!is_software_event(event))
2296 cpuctx->active_oncpu++;
2297 if (!ctx->nr_active++)
2298 perf_event_ctx_activate(ctx);
2299 if (event->attr.freq && event->attr.sample_freq)
2302 if (event->attr.exclusive)
2303 cpuctx->exclusive = 1;
2306 perf_pmu_enable(event->pmu);
2312 group_sched_in(struct perf_event *group_event,
2313 struct perf_cpu_context *cpuctx,
2314 struct perf_event_context *ctx)
2316 struct perf_event *event, *partial_group = NULL;
2317 struct pmu *pmu = ctx->pmu;
2319 if (group_event->state == PERF_EVENT_STATE_OFF)
2322 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2324 if (event_sched_in(group_event, cpuctx, ctx)) {
2325 pmu->cancel_txn(pmu);
2326 perf_mux_hrtimer_restart(cpuctx);
2331 * Schedule in siblings as one group (if any):
2333 for_each_sibling_event(event, group_event) {
2334 if (event_sched_in(event, cpuctx, ctx)) {
2335 partial_group = event;
2340 if (!pmu->commit_txn(pmu))
2345 * Groups can be scheduled in as one unit only, so undo any
2346 * partial group before returning:
2347 * The events up to the failed event are scheduled out normally.
2349 for_each_sibling_event(event, group_event) {
2350 if (event == partial_group)
2353 event_sched_out(event, cpuctx, ctx);
2355 event_sched_out(group_event, cpuctx, ctx);
2357 pmu->cancel_txn(pmu);
2359 perf_mux_hrtimer_restart(cpuctx);
2365 * Work out whether we can put this event group on the CPU now.
2367 static int group_can_go_on(struct perf_event *event,
2368 struct perf_cpu_context *cpuctx,
2372 * Groups consisting entirely of software events can always go on.
2374 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2377 * If an exclusive group is already on, no other hardware
2380 if (cpuctx->exclusive)
2383 * If this group is exclusive and there are already
2384 * events on the CPU, it can't go on.
2386 if (event->attr.exclusive && cpuctx->active_oncpu)
2389 * Otherwise, try to add it if all previous groups were able
2395 static void add_event_to_ctx(struct perf_event *event,
2396 struct perf_event_context *ctx)
2398 list_add_event(event, ctx);
2399 perf_group_attach(event);
2402 static void ctx_sched_out(struct perf_event_context *ctx,
2403 struct perf_cpu_context *cpuctx,
2404 enum event_type_t event_type);
2406 ctx_sched_in(struct perf_event_context *ctx,
2407 struct perf_cpu_context *cpuctx,
2408 enum event_type_t event_type,
2409 struct task_struct *task);
2411 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2412 struct perf_event_context *ctx,
2413 enum event_type_t event_type)
2415 if (!cpuctx->task_ctx)
2418 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2421 ctx_sched_out(ctx, cpuctx, event_type);
2424 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2425 struct perf_event_context *ctx,
2426 struct task_struct *task)
2428 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2430 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2431 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2433 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2437 * We want to maintain the following priority of scheduling:
2438 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2439 * - task pinned (EVENT_PINNED)
2440 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2441 * - task flexible (EVENT_FLEXIBLE).
2443 * In order to avoid unscheduling and scheduling back in everything every
2444 * time an event is added, only do it for the groups of equal priority and
2447 * This can be called after a batch operation on task events, in which case
2448 * event_type is a bit mask of the types of events involved. For CPU events,
2449 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2451 static void ctx_resched(struct perf_cpu_context *cpuctx,
2452 struct perf_event_context *task_ctx,
2453 enum event_type_t event_type)
2455 enum event_type_t ctx_event_type;
2456 bool cpu_event = !!(event_type & EVENT_CPU);
2459 * If pinned groups are involved, flexible groups also need to be
2462 if (event_type & EVENT_PINNED)
2463 event_type |= EVENT_FLEXIBLE;
2465 ctx_event_type = event_type & EVENT_ALL;
2467 perf_pmu_disable(cpuctx->ctx.pmu);
2469 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2472 * Decide which cpu ctx groups to schedule out based on the types
2473 * of events that caused rescheduling:
2474 * - EVENT_CPU: schedule out corresponding groups;
2475 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2476 * - otherwise, do nothing more.
2479 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2480 else if (ctx_event_type & EVENT_PINNED)
2481 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2483 perf_event_sched_in(cpuctx, task_ctx, current);
2484 perf_pmu_enable(cpuctx->ctx.pmu);
2488 * Cross CPU call to install and enable a performance event
2490 * Very similar to remote_function() + event_function() but cannot assume that
2491 * things like ctx->is_active and cpuctx->task_ctx are set.
2493 static int __perf_install_in_context(void *info)
2495 struct perf_event *event = info;
2496 struct perf_event_context *ctx = event->ctx;
2497 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2498 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2499 bool reprogram = true;
2502 raw_spin_lock(&cpuctx->ctx.lock);
2504 raw_spin_lock(&ctx->lock);
2507 reprogram = (ctx->task == current);
2510 * If the task is running, it must be running on this CPU,
2511 * otherwise we cannot reprogram things.
2513 * If its not running, we don't care, ctx->lock will
2514 * serialize against it becoming runnable.
2516 if (task_curr(ctx->task) && !reprogram) {
2521 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2522 } else if (task_ctx) {
2523 raw_spin_lock(&task_ctx->lock);
2526 #ifdef CONFIG_CGROUP_PERF
2527 if (is_cgroup_event(event)) {
2529 * If the current cgroup doesn't match the event's
2530 * cgroup, we should not try to schedule it.
2532 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2533 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2534 event->cgrp->css.cgroup);
2539 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2540 add_event_to_ctx(event, ctx);
2541 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2543 add_event_to_ctx(event, ctx);
2547 perf_ctx_unlock(cpuctx, task_ctx);
2552 static bool exclusive_event_installable(struct perf_event *event,
2553 struct perf_event_context *ctx);
2556 * Attach a performance event to a context.
2558 * Very similar to event_function_call, see comment there.
2561 perf_install_in_context(struct perf_event_context *ctx,
2562 struct perf_event *event,
2565 struct task_struct *task = READ_ONCE(ctx->task);
2567 lockdep_assert_held(&ctx->mutex);
2569 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2571 if (event->cpu != -1)
2575 * Ensures that if we can observe event->ctx, both the event and ctx
2576 * will be 'complete'. See perf_iterate_sb_cpu().
2578 smp_store_release(&event->ctx, ctx);
2581 cpu_function_call(cpu, __perf_install_in_context, event);
2586 * Should not happen, we validate the ctx is still alive before calling.
2588 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2592 * Installing events is tricky because we cannot rely on ctx->is_active
2593 * to be set in case this is the nr_events 0 -> 1 transition.
2595 * Instead we use task_curr(), which tells us if the task is running.
2596 * However, since we use task_curr() outside of rq::lock, we can race
2597 * against the actual state. This means the result can be wrong.
2599 * If we get a false positive, we retry, this is harmless.
2601 * If we get a false negative, things are complicated. If we are after
2602 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2603 * value must be correct. If we're before, it doesn't matter since
2604 * perf_event_context_sched_in() will program the counter.
2606 * However, this hinges on the remote context switch having observed
2607 * our task->perf_event_ctxp[] store, such that it will in fact take
2608 * ctx::lock in perf_event_context_sched_in().
2610 * We do this by task_function_call(), if the IPI fails to hit the task
2611 * we know any future context switch of task must see the
2612 * perf_event_ctpx[] store.
2616 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2617 * task_cpu() load, such that if the IPI then does not find the task
2618 * running, a future context switch of that task must observe the
2623 if (!task_function_call(task, __perf_install_in_context, event))
2626 raw_spin_lock_irq(&ctx->lock);
2628 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2630 * Cannot happen because we already checked above (which also
2631 * cannot happen), and we hold ctx->mutex, which serializes us
2632 * against perf_event_exit_task_context().
2634 raw_spin_unlock_irq(&ctx->lock);
2638 * If the task is not running, ctx->lock will avoid it becoming so,
2639 * thus we can safely install the event.
2641 if (task_curr(task)) {
2642 raw_spin_unlock_irq(&ctx->lock);
2645 add_event_to_ctx(event, ctx);
2646 raw_spin_unlock_irq(&ctx->lock);
2650 * Cross CPU call to enable a performance event
2652 static void __perf_event_enable(struct perf_event *event,
2653 struct perf_cpu_context *cpuctx,
2654 struct perf_event_context *ctx,
2657 struct perf_event *leader = event->group_leader;
2658 struct perf_event_context *task_ctx;
2660 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2661 event->state <= PERF_EVENT_STATE_ERROR)
2665 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2667 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2669 if (!ctx->is_active)
2672 if (!event_filter_match(event)) {
2673 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2678 * If the event is in a group and isn't the group leader,
2679 * then don't put it on unless the group is on.
2681 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2682 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2686 task_ctx = cpuctx->task_ctx;
2688 WARN_ON_ONCE(task_ctx != ctx);
2690 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2696 * If event->ctx is a cloned context, callers must make sure that
2697 * every task struct that event->ctx->task could possibly point to
2698 * remains valid. This condition is satisfied when called through
2699 * perf_event_for_each_child or perf_event_for_each as described
2700 * for perf_event_disable.
2702 static void _perf_event_enable(struct perf_event *event)
2704 struct perf_event_context *ctx = event->ctx;
2706 raw_spin_lock_irq(&ctx->lock);
2707 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2708 event->state < PERF_EVENT_STATE_ERROR) {
2709 raw_spin_unlock_irq(&ctx->lock);
2714 * If the event is in error state, clear that first.
2716 * That way, if we see the event in error state below, we know that it
2717 * has gone back into error state, as distinct from the task having
2718 * been scheduled away before the cross-call arrived.
2720 if (event->state == PERF_EVENT_STATE_ERROR)
2721 event->state = PERF_EVENT_STATE_OFF;
2722 raw_spin_unlock_irq(&ctx->lock);
2724 event_function_call(event, __perf_event_enable, NULL);
2728 * See perf_event_disable();
2730 void perf_event_enable(struct perf_event *event)
2732 struct perf_event_context *ctx;
2734 ctx = perf_event_ctx_lock(event);
2735 _perf_event_enable(event);
2736 perf_event_ctx_unlock(event, ctx);
2738 EXPORT_SYMBOL_GPL(perf_event_enable);
2740 struct stop_event_data {
2741 struct perf_event *event;
2742 unsigned int restart;
2745 static int __perf_event_stop(void *info)
2747 struct stop_event_data *sd = info;
2748 struct perf_event *event = sd->event;
2750 /* if it's already INACTIVE, do nothing */
2751 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2754 /* matches smp_wmb() in event_sched_in() */
2758 * There is a window with interrupts enabled before we get here,
2759 * so we need to check again lest we try to stop another CPU's event.
2761 if (READ_ONCE(event->oncpu) != smp_processor_id())
2764 event->pmu->stop(event, PERF_EF_UPDATE);
2767 * May race with the actual stop (through perf_pmu_output_stop()),
2768 * but it is only used for events with AUX ring buffer, and such
2769 * events will refuse to restart because of rb::aux_mmap_count==0,
2770 * see comments in perf_aux_output_begin().
2772 * Since this is happening on an event-local CPU, no trace is lost
2776 event->pmu->start(event, 0);
2781 static int perf_event_stop(struct perf_event *event, int restart)
2783 struct stop_event_data sd = {
2790 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2793 /* matches smp_wmb() in event_sched_in() */
2797 * We only want to restart ACTIVE events, so if the event goes
2798 * inactive here (event->oncpu==-1), there's nothing more to do;
2799 * fall through with ret==-ENXIO.
2801 ret = cpu_function_call(READ_ONCE(event->oncpu),
2802 __perf_event_stop, &sd);
2803 } while (ret == -EAGAIN);
2809 * In order to contain the amount of racy and tricky in the address filter
2810 * configuration management, it is a two part process:
2812 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2813 * we update the addresses of corresponding vmas in
2814 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
2815 * (p2) when an event is scheduled in (pmu::add), it calls
2816 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2817 * if the generation has changed since the previous call.
2819 * If (p1) happens while the event is active, we restart it to force (p2).
2821 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2822 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2824 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2825 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2827 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2830 void perf_event_addr_filters_sync(struct perf_event *event)
2832 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2834 if (!has_addr_filter(event))
2837 raw_spin_lock(&ifh->lock);
2838 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2839 event->pmu->addr_filters_sync(event);
2840 event->hw.addr_filters_gen = event->addr_filters_gen;
2842 raw_spin_unlock(&ifh->lock);
2844 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2846 static int _perf_event_refresh(struct perf_event *event, int refresh)
2849 * not supported on inherited events
2851 if (event->attr.inherit || !is_sampling_event(event))
2854 atomic_add(refresh, &event->event_limit);
2855 _perf_event_enable(event);
2861 * See perf_event_disable()
2863 int perf_event_refresh(struct perf_event *event, int refresh)
2865 struct perf_event_context *ctx;
2868 ctx = perf_event_ctx_lock(event);
2869 ret = _perf_event_refresh(event, refresh);
2870 perf_event_ctx_unlock(event, ctx);
2874 EXPORT_SYMBOL_GPL(perf_event_refresh);
2876 static int perf_event_modify_breakpoint(struct perf_event *bp,
2877 struct perf_event_attr *attr)
2881 _perf_event_disable(bp);
2883 err = modify_user_hw_breakpoint_check(bp, attr, true);
2885 if (!bp->attr.disabled)
2886 _perf_event_enable(bp);
2891 static int perf_event_modify_attr(struct perf_event *event,
2892 struct perf_event_attr *attr)
2894 if (event->attr.type != attr->type)
2897 switch (event->attr.type) {
2898 case PERF_TYPE_BREAKPOINT:
2899 return perf_event_modify_breakpoint(event, attr);
2901 /* Place holder for future additions. */
2906 static void ctx_sched_out(struct perf_event_context *ctx,
2907 struct perf_cpu_context *cpuctx,
2908 enum event_type_t event_type)
2910 struct perf_event *event, *tmp;
2911 int is_active = ctx->is_active;
2913 lockdep_assert_held(&ctx->lock);
2915 if (likely(!ctx->nr_events)) {
2917 * See __perf_remove_from_context().
2919 WARN_ON_ONCE(ctx->is_active);
2921 WARN_ON_ONCE(cpuctx->task_ctx);
2925 ctx->is_active &= ~event_type;
2926 if (!(ctx->is_active & EVENT_ALL))
2930 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2931 if (!ctx->is_active)
2932 cpuctx->task_ctx = NULL;
2936 * Always update time if it was set; not only when it changes.
2937 * Otherwise we can 'forget' to update time for any but the last
2938 * context we sched out. For example:
2940 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2941 * ctx_sched_out(.event_type = EVENT_PINNED)
2943 * would only update time for the pinned events.
2945 if (is_active & EVENT_TIME) {
2946 /* update (and stop) ctx time */
2947 update_context_time(ctx);
2948 update_cgrp_time_from_cpuctx(cpuctx);
2951 is_active ^= ctx->is_active; /* changed bits */
2953 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2956 perf_pmu_disable(ctx->pmu);
2957 if (is_active & EVENT_PINNED) {
2958 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
2959 group_sched_out(event, cpuctx, ctx);
2962 if (is_active & EVENT_FLEXIBLE) {
2963 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
2964 group_sched_out(event, cpuctx, ctx);
2967 * Since we cleared EVENT_FLEXIBLE, also clear
2968 * rotate_necessary, is will be reset by
2969 * ctx_flexible_sched_in() when needed.
2971 ctx->rotate_necessary = 0;
2973 perf_pmu_enable(ctx->pmu);
2977 * Test whether two contexts are equivalent, i.e. whether they have both been
2978 * cloned from the same version of the same context.
2980 * Equivalence is measured using a generation number in the context that is
2981 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2982 * and list_del_event().
2984 static int context_equiv(struct perf_event_context *ctx1,
2985 struct perf_event_context *ctx2)
2987 lockdep_assert_held(&ctx1->lock);
2988 lockdep_assert_held(&ctx2->lock);
2990 /* Pinning disables the swap optimization */
2991 if (ctx1->pin_count || ctx2->pin_count)
2994 /* If ctx1 is the parent of ctx2 */
2995 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2998 /* If ctx2 is the parent of ctx1 */
2999 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3003 * If ctx1 and ctx2 have the same parent; we flatten the parent
3004 * hierarchy, see perf_event_init_context().
3006 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3007 ctx1->parent_gen == ctx2->parent_gen)
3014 static void __perf_event_sync_stat(struct perf_event *event,
3015 struct perf_event *next_event)
3019 if (!event->attr.inherit_stat)
3023 * Update the event value, we cannot use perf_event_read()
3024 * because we're in the middle of a context switch and have IRQs
3025 * disabled, which upsets smp_call_function_single(), however
3026 * we know the event must be on the current CPU, therefore we
3027 * don't need to use it.
3029 if (event->state == PERF_EVENT_STATE_ACTIVE)
3030 event->pmu->read(event);
3032 perf_event_update_time(event);
3035 * In order to keep per-task stats reliable we need to flip the event
3036 * values when we flip the contexts.
3038 value = local64_read(&next_event->count);
3039 value = local64_xchg(&event->count, value);
3040 local64_set(&next_event->count, value);
3042 swap(event->total_time_enabled, next_event->total_time_enabled);
3043 swap(event->total_time_running, next_event->total_time_running);
3046 * Since we swizzled the values, update the user visible data too.
3048 perf_event_update_userpage(event);
3049 perf_event_update_userpage(next_event);
3052 static void perf_event_sync_stat(struct perf_event_context *ctx,
3053 struct perf_event_context *next_ctx)
3055 struct perf_event *event, *next_event;
3060 update_context_time(ctx);
3062 event = list_first_entry(&ctx->event_list,
3063 struct perf_event, event_entry);
3065 next_event = list_first_entry(&next_ctx->event_list,
3066 struct perf_event, event_entry);
3068 while (&event->event_entry != &ctx->event_list &&
3069 &next_event->event_entry != &next_ctx->event_list) {
3071 __perf_event_sync_stat(event, next_event);
3073 event = list_next_entry(event, event_entry);
3074 next_event = list_next_entry(next_event, event_entry);
3078 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3079 struct task_struct *next)
3081 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3082 struct perf_event_context *next_ctx;
3083 struct perf_event_context *parent, *next_parent;
3084 struct perf_cpu_context *cpuctx;
3090 cpuctx = __get_cpu_context(ctx);
3091 if (!cpuctx->task_ctx)
3095 next_ctx = next->perf_event_ctxp[ctxn];
3099 parent = rcu_dereference(ctx->parent_ctx);
3100 next_parent = rcu_dereference(next_ctx->parent_ctx);
3102 /* If neither context have a parent context; they cannot be clones. */
3103 if (!parent && !next_parent)
3106 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3108 * Looks like the two contexts are clones, so we might be
3109 * able to optimize the context switch. We lock both
3110 * contexts and check that they are clones under the
3111 * lock (including re-checking that neither has been
3112 * uncloned in the meantime). It doesn't matter which
3113 * order we take the locks because no other cpu could
3114 * be trying to lock both of these tasks.
3116 raw_spin_lock(&ctx->lock);
3117 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3118 if (context_equiv(ctx, next_ctx)) {
3119 WRITE_ONCE(ctx->task, next);
3120 WRITE_ONCE(next_ctx->task, task);
3122 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3125 * RCU_INIT_POINTER here is safe because we've not
3126 * modified the ctx and the above modification of
3127 * ctx->task and ctx->task_ctx_data are immaterial
3128 * since those values are always verified under
3129 * ctx->lock which we're now holding.
3131 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3132 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3136 perf_event_sync_stat(ctx, next_ctx);
3138 raw_spin_unlock(&next_ctx->lock);
3139 raw_spin_unlock(&ctx->lock);
3145 raw_spin_lock(&ctx->lock);
3146 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3147 raw_spin_unlock(&ctx->lock);
3151 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3153 void perf_sched_cb_dec(struct pmu *pmu)
3155 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3157 this_cpu_dec(perf_sched_cb_usages);
3159 if (!--cpuctx->sched_cb_usage)
3160 list_del(&cpuctx->sched_cb_entry);
3164 void perf_sched_cb_inc(struct pmu *pmu)
3166 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3168 if (!cpuctx->sched_cb_usage++)
3169 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3171 this_cpu_inc(perf_sched_cb_usages);
3175 * This function provides the context switch callback to the lower code
3176 * layer. It is invoked ONLY when the context switch callback is enabled.
3178 * This callback is relevant even to per-cpu events; for example multi event
3179 * PEBS requires this to provide PID/TID information. This requires we flush
3180 * all queued PEBS records before we context switch to a new task.
3182 static void perf_pmu_sched_task(struct task_struct *prev,
3183 struct task_struct *next,
3186 struct perf_cpu_context *cpuctx;
3192 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3193 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3195 if (WARN_ON_ONCE(!pmu->sched_task))
3198 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3199 perf_pmu_disable(pmu);
3201 pmu->sched_task(cpuctx->task_ctx, sched_in);
3203 perf_pmu_enable(pmu);
3204 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3208 static void perf_event_switch(struct task_struct *task,
3209 struct task_struct *next_prev, bool sched_in);
3211 #define for_each_task_context_nr(ctxn) \
3212 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3215 * Called from scheduler to remove the events of the current task,
3216 * with interrupts disabled.
3218 * We stop each event and update the event value in event->count.
3220 * This does not protect us against NMI, but disable()
3221 * sets the disabled bit in the control field of event _before_
3222 * accessing the event control register. If a NMI hits, then it will
3223 * not restart the event.
3225 void __perf_event_task_sched_out(struct task_struct *task,
3226 struct task_struct *next)
3230 if (__this_cpu_read(perf_sched_cb_usages))
3231 perf_pmu_sched_task(task, next, false);
3233 if (atomic_read(&nr_switch_events))
3234 perf_event_switch(task, next, false);
3236 for_each_task_context_nr(ctxn)
3237 perf_event_context_sched_out(task, ctxn, next);
3240 * if cgroup events exist on this CPU, then we need
3241 * to check if we have to switch out PMU state.
3242 * cgroup event are system-wide mode only
3244 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3245 perf_cgroup_sched_out(task, next);
3249 * Called with IRQs disabled
3251 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3252 enum event_type_t event_type)
3254 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3257 static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
3258 int (*func)(struct perf_event *, void *), void *data)
3260 struct perf_event **evt, *evt1, *evt2;
3263 evt1 = perf_event_groups_first(groups, -1);
3264 evt2 = perf_event_groups_first(groups, cpu);
3266 while (evt1 || evt2) {
3268 if (evt1->group_index < evt2->group_index)
3278 ret = func(*evt, data);
3282 *evt = perf_event_groups_next(*evt);
3288 struct sched_in_data {
3289 struct perf_event_context *ctx;
3290 struct perf_cpu_context *cpuctx;
3294 static int pinned_sched_in(struct perf_event *event, void *data)
3296 struct sched_in_data *sid = data;
3298 if (event->state <= PERF_EVENT_STATE_OFF)
3301 if (!event_filter_match(event))
3304 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3305 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3306 list_add_tail(&event->active_list, &sid->ctx->pinned_active);
3310 * If this pinned group hasn't been scheduled,
3311 * put it in error state.
3313 if (event->state == PERF_EVENT_STATE_INACTIVE)
3314 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3319 static int flexible_sched_in(struct perf_event *event, void *data)
3321 struct sched_in_data *sid = data;
3323 if (event->state <= PERF_EVENT_STATE_OFF)
3326 if (!event_filter_match(event))
3329 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3330 int ret = group_sched_in(event, sid->cpuctx, sid->ctx);
3332 sid->can_add_hw = 0;
3333 sid->ctx->rotate_necessary = 1;
3336 list_add_tail(&event->active_list, &sid->ctx->flexible_active);
3343 ctx_pinned_sched_in(struct perf_event_context *ctx,
3344 struct perf_cpu_context *cpuctx)
3346 struct sched_in_data sid = {
3352 visit_groups_merge(&ctx->pinned_groups,
3354 pinned_sched_in, &sid);
3358 ctx_flexible_sched_in(struct perf_event_context *ctx,
3359 struct perf_cpu_context *cpuctx)
3361 struct sched_in_data sid = {
3367 visit_groups_merge(&ctx->flexible_groups,
3369 flexible_sched_in, &sid);
3373 ctx_sched_in(struct perf_event_context *ctx,
3374 struct perf_cpu_context *cpuctx,
3375 enum event_type_t event_type,
3376 struct task_struct *task)
3378 int is_active = ctx->is_active;
3381 lockdep_assert_held(&ctx->lock);
3383 if (likely(!ctx->nr_events))
3386 ctx->is_active |= (event_type | EVENT_TIME);
3389 cpuctx->task_ctx = ctx;
3391 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3394 is_active ^= ctx->is_active; /* changed bits */
3396 if (is_active & EVENT_TIME) {
3397 /* start ctx time */
3399 ctx->timestamp = now;
3400 perf_cgroup_set_timestamp(task, ctx);
3404 * First go through the list and put on any pinned groups
3405 * in order to give them the best chance of going on.
3407 if (is_active & EVENT_PINNED)
3408 ctx_pinned_sched_in(ctx, cpuctx);
3410 /* Then walk through the lower prio flexible groups */
3411 if (is_active & EVENT_FLEXIBLE)
3412 ctx_flexible_sched_in(ctx, cpuctx);
3415 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3416 enum event_type_t event_type,
3417 struct task_struct *task)
3419 struct perf_event_context *ctx = &cpuctx->ctx;
3421 ctx_sched_in(ctx, cpuctx, event_type, task);
3424 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3425 struct task_struct *task)
3427 struct perf_cpu_context *cpuctx;
3429 cpuctx = __get_cpu_context(ctx);
3430 if (cpuctx->task_ctx == ctx)
3433 perf_ctx_lock(cpuctx, ctx);
3435 * We must check ctx->nr_events while holding ctx->lock, such
3436 * that we serialize against perf_install_in_context().
3438 if (!ctx->nr_events)
3441 perf_pmu_disable(ctx->pmu);
3443 * We want to keep the following priority order:
3444 * cpu pinned (that don't need to move), task pinned,
3445 * cpu flexible, task flexible.
3447 * However, if task's ctx is not carrying any pinned
3448 * events, no need to flip the cpuctx's events around.
3450 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3451 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3452 perf_event_sched_in(cpuctx, ctx, task);
3453 perf_pmu_enable(ctx->pmu);
3456 perf_ctx_unlock(cpuctx, ctx);
3460 * Called from scheduler to add the events of the current task
3461 * with interrupts disabled.
3463 * We restore the event value and then enable it.
3465 * This does not protect us against NMI, but enable()
3466 * sets the enabled bit in the control field of event _before_
3467 * accessing the event control register. If a NMI hits, then it will
3468 * keep the event running.
3470 void __perf_event_task_sched_in(struct task_struct *prev,
3471 struct task_struct *task)
3473 struct perf_event_context *ctx;
3477 * If cgroup events exist on this CPU, then we need to check if we have
3478 * to switch in PMU state; cgroup event are system-wide mode only.
3480 * Since cgroup events are CPU events, we must schedule these in before
3481 * we schedule in the task events.
3483 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3484 perf_cgroup_sched_in(prev, task);
3486 for_each_task_context_nr(ctxn) {
3487 ctx = task->perf_event_ctxp[ctxn];
3491 perf_event_context_sched_in(ctx, task);
3494 if (atomic_read(&nr_switch_events))
3495 perf_event_switch(task, prev, true);
3497 if (__this_cpu_read(perf_sched_cb_usages))
3498 perf_pmu_sched_task(prev, task, true);
3501 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3503 u64 frequency = event->attr.sample_freq;
3504 u64 sec = NSEC_PER_SEC;
3505 u64 divisor, dividend;
3507 int count_fls, nsec_fls, frequency_fls, sec_fls;
3509 count_fls = fls64(count);
3510 nsec_fls = fls64(nsec);
3511 frequency_fls = fls64(frequency);
3515 * We got @count in @nsec, with a target of sample_freq HZ
3516 * the target period becomes:
3519 * period = -------------------
3520 * @nsec * sample_freq
3525 * Reduce accuracy by one bit such that @a and @b converge
3526 * to a similar magnitude.
3528 #define REDUCE_FLS(a, b) \
3530 if (a##_fls > b##_fls) { \
3540 * Reduce accuracy until either term fits in a u64, then proceed with
3541 * the other, so that finally we can do a u64/u64 division.
3543 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3544 REDUCE_FLS(nsec, frequency);
3545 REDUCE_FLS(sec, count);
3548 if (count_fls + sec_fls > 64) {
3549 divisor = nsec * frequency;
3551 while (count_fls + sec_fls > 64) {
3552 REDUCE_FLS(count, sec);
3556 dividend = count * sec;
3558 dividend = count * sec;
3560 while (nsec_fls + frequency_fls > 64) {
3561 REDUCE_FLS(nsec, frequency);
3565 divisor = nsec * frequency;
3571 return div64_u64(dividend, divisor);
3574 static DEFINE_PER_CPU(int, perf_throttled_count);
3575 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3577 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3579 struct hw_perf_event *hwc = &event->hw;
3580 s64 period, sample_period;
3583 period = perf_calculate_period(event, nsec, count);
3585 delta = (s64)(period - hwc->sample_period);
3586 delta = (delta + 7) / 8; /* low pass filter */
3588 sample_period = hwc->sample_period + delta;
3593 hwc->sample_period = sample_period;
3595 if (local64_read(&hwc->period_left) > 8*sample_period) {
3597 event->pmu->stop(event, PERF_EF_UPDATE);
3599 local64_set(&hwc->period_left, 0);
3602 event->pmu->start(event, PERF_EF_RELOAD);
3607 * combine freq adjustment with unthrottling to avoid two passes over the
3608 * events. At the same time, make sure, having freq events does not change
3609 * the rate of unthrottling as that would introduce bias.
3611 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3614 struct perf_event *event;
3615 struct hw_perf_event *hwc;
3616 u64 now, period = TICK_NSEC;
3620 * only need to iterate over all events iff:
3621 * - context have events in frequency mode (needs freq adjust)
3622 * - there are events to unthrottle on this cpu
3624 if (!(ctx->nr_freq || needs_unthr))
3627 raw_spin_lock(&ctx->lock);
3628 perf_pmu_disable(ctx->pmu);
3630 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3631 if (event->state != PERF_EVENT_STATE_ACTIVE)
3634 if (!event_filter_match(event))
3637 perf_pmu_disable(event->pmu);
3641 if (hwc->interrupts == MAX_INTERRUPTS) {
3642 hwc->interrupts = 0;
3643 perf_log_throttle(event, 1);
3644 event->pmu->start(event, 0);
3647 if (!event->attr.freq || !event->attr.sample_freq)
3651 * stop the event and update event->count
3653 event->pmu->stop(event, PERF_EF_UPDATE);
3655 now = local64_read(&event->count);
3656 delta = now - hwc->freq_count_stamp;
3657 hwc->freq_count_stamp = now;
3661 * reload only if value has changed
3662 * we have stopped the event so tell that
3663 * to perf_adjust_period() to avoid stopping it
3667 perf_adjust_period(event, period, delta, false);
3669 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3671 perf_pmu_enable(event->pmu);
3674 perf_pmu_enable(ctx->pmu);
3675 raw_spin_unlock(&ctx->lock);
3679 * Move @event to the tail of the @ctx's elegible events.
3681 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
3684 * Rotate the first entry last of non-pinned groups. Rotation might be
3685 * disabled by the inheritance code.
3687 if (ctx->rotate_disable)
3690 perf_event_groups_delete(&ctx->flexible_groups, event);
3691 perf_event_groups_insert(&ctx->flexible_groups, event);
3694 /* pick an event from the flexible_groups to rotate */
3695 static inline struct perf_event *
3696 ctx_event_to_rotate(struct perf_event_context *ctx)
3698 struct perf_event *event;
3700 /* pick the first active flexible event */
3701 event = list_first_entry_or_null(&ctx->flexible_active,
3702 struct perf_event, active_list);
3704 /* if no active flexible event, pick the first event */
3706 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
3707 typeof(*event), group_node);
3711 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
3712 * finds there are unschedulable events, it will set it again.
3714 ctx->rotate_necessary = 0;
3719 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
3721 struct perf_event *cpu_event = NULL, *task_event = NULL;
3722 struct perf_event_context *task_ctx = NULL;
3723 int cpu_rotate, task_rotate;
3726 * Since we run this from IRQ context, nobody can install new
3727 * events, thus the event count values are stable.
3730 cpu_rotate = cpuctx->ctx.rotate_necessary;
3731 task_ctx = cpuctx->task_ctx;
3732 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
3734 if (!(cpu_rotate || task_rotate))
3737 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3738 perf_pmu_disable(cpuctx->ctx.pmu);
3741 task_event = ctx_event_to_rotate(task_ctx);
3743 cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
3746 * As per the order given at ctx_resched() first 'pop' task flexible
3747 * and then, if needed CPU flexible.
3749 if (task_event || (task_ctx && cpu_event))
3750 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
3752 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3755 rotate_ctx(task_ctx, task_event);
3757 rotate_ctx(&cpuctx->ctx, cpu_event);
3759 perf_event_sched_in(cpuctx, task_ctx, current);
3761 perf_pmu_enable(cpuctx->ctx.pmu);
3762 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3767 void perf_event_task_tick(void)
3769 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3770 struct perf_event_context *ctx, *tmp;
3773 lockdep_assert_irqs_disabled();
3775 __this_cpu_inc(perf_throttled_seq);
3776 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3777 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3779 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3780 perf_adjust_freq_unthr_context(ctx, throttled);
3783 static int event_enable_on_exec(struct perf_event *event,
3784 struct perf_event_context *ctx)
3786 if (!event->attr.enable_on_exec)
3789 event->attr.enable_on_exec = 0;
3790 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3793 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3799 * Enable all of a task's events that have been marked enable-on-exec.
3800 * This expects task == current.
3802 static void perf_event_enable_on_exec(int ctxn)
3804 struct perf_event_context *ctx, *clone_ctx = NULL;
3805 enum event_type_t event_type = 0;
3806 struct perf_cpu_context *cpuctx;
3807 struct perf_event *event;
3808 unsigned long flags;
3811 local_irq_save(flags);
3812 ctx = current->perf_event_ctxp[ctxn];
3813 if (!ctx || !ctx->nr_events)
3816 cpuctx = __get_cpu_context(ctx);
3817 perf_ctx_lock(cpuctx, ctx);
3818 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3819 list_for_each_entry(event, &ctx->event_list, event_entry) {
3820 enabled |= event_enable_on_exec(event, ctx);
3821 event_type |= get_event_type(event);
3825 * Unclone and reschedule this context if we enabled any event.
3828 clone_ctx = unclone_ctx(ctx);
3829 ctx_resched(cpuctx, ctx, event_type);
3831 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3833 perf_ctx_unlock(cpuctx, ctx);
3836 local_irq_restore(flags);
3842 struct perf_read_data {
3843 struct perf_event *event;
3848 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3850 u16 local_pkg, event_pkg;
3852 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3853 int local_cpu = smp_processor_id();
3855 event_pkg = topology_physical_package_id(event_cpu);
3856 local_pkg = topology_physical_package_id(local_cpu);
3858 if (event_pkg == local_pkg)
3866 * Cross CPU call to read the hardware event
3868 static void __perf_event_read(void *info)
3870 struct perf_read_data *data = info;
3871 struct perf_event *sub, *event = data->event;
3872 struct perf_event_context *ctx = event->ctx;
3873 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3874 struct pmu *pmu = event->pmu;
3877 * If this is a task context, we need to check whether it is
3878 * the current task context of this cpu. If not it has been
3879 * scheduled out before the smp call arrived. In that case
3880 * event->count would have been updated to a recent sample
3881 * when the event was scheduled out.
3883 if (ctx->task && cpuctx->task_ctx != ctx)
3886 raw_spin_lock(&ctx->lock);
3887 if (ctx->is_active & EVENT_TIME) {
3888 update_context_time(ctx);
3889 update_cgrp_time_from_event(event);
3892 perf_event_update_time(event);
3894 perf_event_update_sibling_time(event);
3896 if (event->state != PERF_EVENT_STATE_ACTIVE)
3905 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3909 for_each_sibling_event(sub, event) {
3910 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3912 * Use sibling's PMU rather than @event's since
3913 * sibling could be on different (eg: software) PMU.
3915 sub->pmu->read(sub);
3919 data->ret = pmu->commit_txn(pmu);
3922 raw_spin_unlock(&ctx->lock);
3925 static inline u64 perf_event_count(struct perf_event *event)
3927 return local64_read(&event->count) + atomic64_read(&event->child_count);
3931 * NMI-safe method to read a local event, that is an event that
3933 * - either for the current task, or for this CPU
3934 * - does not have inherit set, for inherited task events
3935 * will not be local and we cannot read them atomically
3936 * - must not have a pmu::count method
3938 int perf_event_read_local(struct perf_event *event, u64 *value,
3939 u64 *enabled, u64 *running)
3941 unsigned long flags;
3945 * Disabling interrupts avoids all counter scheduling (context
3946 * switches, timer based rotation and IPIs).
3948 local_irq_save(flags);
3951 * It must not be an event with inherit set, we cannot read
3952 * all child counters from atomic context.
3954 if (event->attr.inherit) {
3959 /* If this is a per-task event, it must be for current */
3960 if ((event->attach_state & PERF_ATTACH_TASK) &&
3961 event->hw.target != current) {
3966 /* If this is a per-CPU event, it must be for this CPU */
3967 if (!(event->attach_state & PERF_ATTACH_TASK) &&
3968 event->cpu != smp_processor_id()) {
3973 /* If this is a pinned event it must be running on this CPU */
3974 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
3980 * If the event is currently on this CPU, its either a per-task event,
3981 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3984 if (event->oncpu == smp_processor_id())
3985 event->pmu->read(event);
3987 *value = local64_read(&event->count);
3988 if (enabled || running) {
3989 u64 now = event->shadow_ctx_time + perf_clock();
3990 u64 __enabled, __running;
3992 __perf_update_times(event, now, &__enabled, &__running);
3994 *enabled = __enabled;
3996 *running = __running;
3999 local_irq_restore(flags);
4004 static int perf_event_read(struct perf_event *event, bool group)
4006 enum perf_event_state state = READ_ONCE(event->state);
4007 int event_cpu, ret = 0;
4010 * If event is enabled and currently active on a CPU, update the
4011 * value in the event structure:
4014 if (state == PERF_EVENT_STATE_ACTIVE) {
4015 struct perf_read_data data;
4018 * Orders the ->state and ->oncpu loads such that if we see
4019 * ACTIVE we must also see the right ->oncpu.
4021 * Matches the smp_wmb() from event_sched_in().
4025 event_cpu = READ_ONCE(event->oncpu);
4026 if ((unsigned)event_cpu >= nr_cpu_ids)
4029 data = (struct perf_read_data){
4036 event_cpu = __perf_event_read_cpu(event, event_cpu);
4039 * Purposely ignore the smp_call_function_single() return
4042 * If event_cpu isn't a valid CPU it means the event got
4043 * scheduled out and that will have updated the event count.
4045 * Therefore, either way, we'll have an up-to-date event count
4048 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4052 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4053 struct perf_event_context *ctx = event->ctx;
4054 unsigned long flags;
4056 raw_spin_lock_irqsave(&ctx->lock, flags);
4057 state = event->state;
4058 if (state != PERF_EVENT_STATE_INACTIVE) {
4059 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4064 * May read while context is not active (e.g., thread is
4065 * blocked), in that case we cannot update context time
4067 if (ctx->is_active & EVENT_TIME) {
4068 update_context_time(ctx);
4069 update_cgrp_time_from_event(event);
4072 perf_event_update_time(event);
4074 perf_event_update_sibling_time(event);
4075 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4082 * Initialize the perf_event context in a task_struct:
4084 static void __perf_event_init_context(struct perf_event_context *ctx)
4086 raw_spin_lock_init(&ctx->lock);
4087 mutex_init(&ctx->mutex);
4088 INIT_LIST_HEAD(&ctx->active_ctx_list);
4089 perf_event_groups_init(&ctx->pinned_groups);
4090 perf_event_groups_init(&ctx->flexible_groups);
4091 INIT_LIST_HEAD(&ctx->event_list);
4092 INIT_LIST_HEAD(&ctx->pinned_active);
4093 INIT_LIST_HEAD(&ctx->flexible_active);
4094 atomic_set(&ctx->refcount, 1);
4097 static struct perf_event_context *
4098 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4100 struct perf_event_context *ctx;
4102 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4106 __perf_event_init_context(ctx);
4109 get_task_struct(task);
4116 static struct task_struct *
4117 find_lively_task_by_vpid(pid_t vpid)
4119 struct task_struct *task;
4125 task = find_task_by_vpid(vpid);
4127 get_task_struct(task);
4131 return ERR_PTR(-ESRCH);
4137 * Returns a matching context with refcount and pincount.
4139 static struct perf_event_context *
4140 find_get_context(struct pmu *pmu, struct task_struct *task,
4141 struct perf_event *event)
4143 struct perf_event_context *ctx, *clone_ctx = NULL;
4144 struct perf_cpu_context *cpuctx;
4145 void *task_ctx_data = NULL;
4146 unsigned long flags;
4148 int cpu = event->cpu;
4151 /* Must be root to operate on a CPU event: */
4152 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
4153 return ERR_PTR(-EACCES);
4155 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4158 raw_spin_lock_irqsave(&ctx->lock, flags);
4160 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4166 ctxn = pmu->task_ctx_nr;
4170 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4171 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4172 if (!task_ctx_data) {
4179 ctx = perf_lock_task_context(task, ctxn, &flags);
4181 clone_ctx = unclone_ctx(ctx);
4184 if (task_ctx_data && !ctx->task_ctx_data) {
4185 ctx->task_ctx_data = task_ctx_data;
4186 task_ctx_data = NULL;
4188 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4193 ctx = alloc_perf_context(pmu, task);
4198 if (task_ctx_data) {
4199 ctx->task_ctx_data = task_ctx_data;
4200 task_ctx_data = NULL;
4204 mutex_lock(&task->perf_event_mutex);
4206 * If it has already passed perf_event_exit_task().
4207 * we must see PF_EXITING, it takes this mutex too.
4209 if (task->flags & PF_EXITING)
4211 else if (task->perf_event_ctxp[ctxn])
4216 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4218 mutex_unlock(&task->perf_event_mutex);
4220 if (unlikely(err)) {
4229 kfree(task_ctx_data);
4233 kfree(task_ctx_data);
4234 return ERR_PTR(err);
4237 static void perf_event_free_filter(struct perf_event *event);
4238 static void perf_event_free_bpf_prog(struct perf_event *event);
4240 static void free_event_rcu(struct rcu_head *head)
4242 struct perf_event *event;
4244 event = container_of(head, struct perf_event, rcu_head);
4246 put_pid_ns(event->ns);
4247 perf_event_free_filter(event);
4251 static void ring_buffer_attach(struct perf_event *event,
4252 struct ring_buffer *rb);
4254 static void detach_sb_event(struct perf_event *event)
4256 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4258 raw_spin_lock(&pel->lock);
4259 list_del_rcu(&event->sb_list);
4260 raw_spin_unlock(&pel->lock);
4263 static bool is_sb_event(struct perf_event *event)
4265 struct perf_event_attr *attr = &event->attr;
4270 if (event->attach_state & PERF_ATTACH_TASK)
4273 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4274 attr->comm || attr->comm_exec ||
4276 attr->context_switch)
4281 static void unaccount_pmu_sb_event(struct perf_event *event)
4283 if (is_sb_event(event))
4284 detach_sb_event(event);
4287 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4292 if (is_cgroup_event(event))
4293 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4296 #ifdef CONFIG_NO_HZ_FULL
4297 static DEFINE_SPINLOCK(nr_freq_lock);
4300 static void unaccount_freq_event_nohz(void)
4302 #ifdef CONFIG_NO_HZ_FULL
4303 spin_lock(&nr_freq_lock);
4304 if (atomic_dec_and_test(&nr_freq_events))
4305 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4306 spin_unlock(&nr_freq_lock);
4310 static void unaccount_freq_event(void)
4312 if (tick_nohz_full_enabled())
4313 unaccount_freq_event_nohz();
4315 atomic_dec(&nr_freq_events);
4318 static void unaccount_event(struct perf_event *event)
4325 if (event->attach_state & PERF_ATTACH_TASK)
4327 if (event->attr.mmap || event->attr.mmap_data)
4328 atomic_dec(&nr_mmap_events);
4329 if (event->attr.comm)
4330 atomic_dec(&nr_comm_events);
4331 if (event->attr.namespaces)
4332 atomic_dec(&nr_namespaces_events);
4333 if (event->attr.task)
4334 atomic_dec(&nr_task_events);
4335 if (event->attr.freq)
4336 unaccount_freq_event();
4337 if (event->attr.context_switch) {
4339 atomic_dec(&nr_switch_events);
4341 if (is_cgroup_event(event))
4343 if (has_branch_stack(event))
4347 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4348 schedule_delayed_work(&perf_sched_work, HZ);
4351 unaccount_event_cpu(event, event->cpu);
4353 unaccount_pmu_sb_event(event);
4356 static void perf_sched_delayed(struct work_struct *work)
4358 mutex_lock(&perf_sched_mutex);
4359 if (atomic_dec_and_test(&perf_sched_count))
4360 static_branch_disable(&perf_sched_events);
4361 mutex_unlock(&perf_sched_mutex);
4365 * The following implement mutual exclusion of events on "exclusive" pmus
4366 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4367 * at a time, so we disallow creating events that might conflict, namely:
4369 * 1) cpu-wide events in the presence of per-task events,
4370 * 2) per-task events in the presence of cpu-wide events,
4371 * 3) two matching events on the same context.
4373 * The former two cases are handled in the allocation path (perf_event_alloc(),
4374 * _free_event()), the latter -- before the first perf_install_in_context().
4376 static int exclusive_event_init(struct perf_event *event)
4378 struct pmu *pmu = event->pmu;
4380 if (!is_exclusive_pmu(pmu))
4384 * Prevent co-existence of per-task and cpu-wide events on the
4385 * same exclusive pmu.
4387 * Negative pmu::exclusive_cnt means there are cpu-wide
4388 * events on this "exclusive" pmu, positive means there are
4391 * Since this is called in perf_event_alloc() path, event::ctx
4392 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4393 * to mean "per-task event", because unlike other attach states it
4394 * never gets cleared.
4396 if (event->attach_state & PERF_ATTACH_TASK) {
4397 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4400 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4407 static void exclusive_event_destroy(struct perf_event *event)
4409 struct pmu *pmu = event->pmu;
4411 if (!is_exclusive_pmu(pmu))
4414 /* see comment in exclusive_event_init() */
4415 if (event->attach_state & PERF_ATTACH_TASK)
4416 atomic_dec(&pmu->exclusive_cnt);
4418 atomic_inc(&pmu->exclusive_cnt);
4421 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4423 if ((e1->pmu == e2->pmu) &&
4424 (e1->cpu == e2->cpu ||
4431 static bool exclusive_event_installable(struct perf_event *event,
4432 struct perf_event_context *ctx)
4434 struct perf_event *iter_event;
4435 struct pmu *pmu = event->pmu;
4437 lockdep_assert_held(&ctx->mutex);
4439 if (!is_exclusive_pmu(pmu))
4442 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4443 if (exclusive_event_match(iter_event, event))
4450 static void perf_addr_filters_splice(struct perf_event *event,
4451 struct list_head *head);
4453 static void _free_event(struct perf_event *event)
4455 irq_work_sync(&event->pending);
4457 unaccount_event(event);
4461 * Can happen when we close an event with re-directed output.
4463 * Since we have a 0 refcount, perf_mmap_close() will skip
4464 * over us; possibly making our ring_buffer_put() the last.
4466 mutex_lock(&event->mmap_mutex);
4467 ring_buffer_attach(event, NULL);
4468 mutex_unlock(&event->mmap_mutex);
4471 if (is_cgroup_event(event))
4472 perf_detach_cgroup(event);
4474 if (!event->parent) {
4475 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4476 put_callchain_buffers();
4479 perf_event_free_bpf_prog(event);
4480 perf_addr_filters_splice(event, NULL);
4481 kfree(event->addr_filter_ranges);
4484 event->destroy(event);
4487 * Must be after ->destroy(), due to uprobe_perf_close() using
4490 if (event->hw.target)
4491 put_task_struct(event->hw.target);
4494 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4495 * all task references must be cleaned up.
4498 put_ctx(event->ctx);
4500 exclusive_event_destroy(event);
4501 module_put(event->pmu->module);
4503 call_rcu(&event->rcu_head, free_event_rcu);
4507 * Used to free events which have a known refcount of 1, such as in error paths
4508 * where the event isn't exposed yet and inherited events.
4510 static void free_event(struct perf_event *event)
4512 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4513 "unexpected event refcount: %ld; ptr=%p\n",
4514 atomic_long_read(&event->refcount), event)) {
4515 /* leak to avoid use-after-free */
4523 * Remove user event from the owner task.
4525 static void perf_remove_from_owner(struct perf_event *event)
4527 struct task_struct *owner;
4531 * Matches the smp_store_release() in perf_event_exit_task(). If we
4532 * observe !owner it means the list deletion is complete and we can
4533 * indeed free this event, otherwise we need to serialize on
4534 * owner->perf_event_mutex.
4536 owner = READ_ONCE(event->owner);
4539 * Since delayed_put_task_struct() also drops the last
4540 * task reference we can safely take a new reference
4541 * while holding the rcu_read_lock().
4543 get_task_struct(owner);
4549 * If we're here through perf_event_exit_task() we're already
4550 * holding ctx->mutex which would be an inversion wrt. the
4551 * normal lock order.
4553 * However we can safely take this lock because its the child
4556 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4559 * We have to re-check the event->owner field, if it is cleared
4560 * we raced with perf_event_exit_task(), acquiring the mutex
4561 * ensured they're done, and we can proceed with freeing the
4565 list_del_init(&event->owner_entry);
4566 smp_store_release(&event->owner, NULL);
4568 mutex_unlock(&owner->perf_event_mutex);
4569 put_task_struct(owner);
4573 static void put_event(struct perf_event *event)
4575 if (!atomic_long_dec_and_test(&event->refcount))
4582 * Kill an event dead; while event:refcount will preserve the event
4583 * object, it will not preserve its functionality. Once the last 'user'
4584 * gives up the object, we'll destroy the thing.
4586 int perf_event_release_kernel(struct perf_event *event)
4588 struct perf_event_context *ctx = event->ctx;
4589 struct perf_event *child, *tmp;
4590 LIST_HEAD(free_list);
4593 * If we got here through err_file: fput(event_file); we will not have
4594 * attached to a context yet.
4597 WARN_ON_ONCE(event->attach_state &
4598 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4602 if (!is_kernel_event(event))
4603 perf_remove_from_owner(event);
4605 ctx = perf_event_ctx_lock(event);
4606 WARN_ON_ONCE(ctx->parent_ctx);
4607 perf_remove_from_context(event, DETACH_GROUP);
4609 raw_spin_lock_irq(&ctx->lock);
4611 * Mark this event as STATE_DEAD, there is no external reference to it
4614 * Anybody acquiring event->child_mutex after the below loop _must_
4615 * also see this, most importantly inherit_event() which will avoid
4616 * placing more children on the list.
4618 * Thus this guarantees that we will in fact observe and kill _ALL_
4621 event->state = PERF_EVENT_STATE_DEAD;
4622 raw_spin_unlock_irq(&ctx->lock);
4624 perf_event_ctx_unlock(event, ctx);
4627 mutex_lock(&event->child_mutex);
4628 list_for_each_entry(child, &event->child_list, child_list) {
4631 * Cannot change, child events are not migrated, see the
4632 * comment with perf_event_ctx_lock_nested().
4634 ctx = READ_ONCE(child->ctx);
4636 * Since child_mutex nests inside ctx::mutex, we must jump
4637 * through hoops. We start by grabbing a reference on the ctx.
4639 * Since the event cannot get freed while we hold the
4640 * child_mutex, the context must also exist and have a !0
4646 * Now that we have a ctx ref, we can drop child_mutex, and
4647 * acquire ctx::mutex without fear of it going away. Then we
4648 * can re-acquire child_mutex.
4650 mutex_unlock(&event->child_mutex);
4651 mutex_lock(&ctx->mutex);
4652 mutex_lock(&event->child_mutex);
4655 * Now that we hold ctx::mutex and child_mutex, revalidate our
4656 * state, if child is still the first entry, it didn't get freed
4657 * and we can continue doing so.
4659 tmp = list_first_entry_or_null(&event->child_list,
4660 struct perf_event, child_list);
4662 perf_remove_from_context(child, DETACH_GROUP);
4663 list_move(&child->child_list, &free_list);
4665 * This matches the refcount bump in inherit_event();
4666 * this can't be the last reference.
4671 mutex_unlock(&event->child_mutex);
4672 mutex_unlock(&ctx->mutex);
4676 mutex_unlock(&event->child_mutex);
4678 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4679 void *var = &child->ctx->refcount;
4681 list_del(&child->child_list);
4685 * Wake any perf_event_free_task() waiting for this event to be
4688 smp_mb(); /* pairs with wait_var_event() */
4693 put_event(event); /* Must be the 'last' reference */
4696 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4699 * Called when the last reference to the file is gone.
4701 static int perf_release(struct inode *inode, struct file *file)
4703 perf_event_release_kernel(file->private_data);
4707 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4709 struct perf_event *child;
4715 mutex_lock(&event->child_mutex);
4717 (void)perf_event_read(event, false);
4718 total += perf_event_count(event);
4720 *enabled += event->total_time_enabled +
4721 atomic64_read(&event->child_total_time_enabled);
4722 *running += event->total_time_running +
4723 atomic64_read(&event->child_total_time_running);
4725 list_for_each_entry(child, &event->child_list, child_list) {
4726 (void)perf_event_read(child, false);
4727 total += perf_event_count(child);
4728 *enabled += child->total_time_enabled;
4729 *running += child->total_time_running;
4731 mutex_unlock(&event->child_mutex);
4736 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4738 struct perf_event_context *ctx;
4741 ctx = perf_event_ctx_lock(event);
4742 count = __perf_event_read_value(event, enabled, running);
4743 perf_event_ctx_unlock(event, ctx);
4747 EXPORT_SYMBOL_GPL(perf_event_read_value);
4749 static int __perf_read_group_add(struct perf_event *leader,
4750 u64 read_format, u64 *values)
4752 struct perf_event_context *ctx = leader->ctx;
4753 struct perf_event *sub;
4754 unsigned long flags;
4755 int n = 1; /* skip @nr */
4758 ret = perf_event_read(leader, true);
4762 raw_spin_lock_irqsave(&ctx->lock, flags);
4765 * Since we co-schedule groups, {enabled,running} times of siblings
4766 * will be identical to those of the leader, so we only publish one
4769 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4770 values[n++] += leader->total_time_enabled +
4771 atomic64_read(&leader->child_total_time_enabled);
4774 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4775 values[n++] += leader->total_time_running +
4776 atomic64_read(&leader->child_total_time_running);
4780 * Write {count,id} tuples for every sibling.
4782 values[n++] += perf_event_count(leader);
4783 if (read_format & PERF_FORMAT_ID)
4784 values[n++] = primary_event_id(leader);
4786 for_each_sibling_event(sub, leader) {
4787 values[n++] += perf_event_count(sub);
4788 if (read_format & PERF_FORMAT_ID)
4789 values[n++] = primary_event_id(sub);
4792 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4796 static int perf_read_group(struct perf_event *event,
4797 u64 read_format, char __user *buf)
4799 struct perf_event *leader = event->group_leader, *child;
4800 struct perf_event_context *ctx = leader->ctx;
4804 lockdep_assert_held(&ctx->mutex);
4806 values = kzalloc(event->read_size, GFP_KERNEL);
4810 values[0] = 1 + leader->nr_siblings;
4813 * By locking the child_mutex of the leader we effectively
4814 * lock the child list of all siblings.. XXX explain how.
4816 mutex_lock(&leader->child_mutex);
4818 ret = __perf_read_group_add(leader, read_format, values);
4822 list_for_each_entry(child, &leader->child_list, child_list) {
4823 ret = __perf_read_group_add(child, read_format, values);
4828 mutex_unlock(&leader->child_mutex);
4830 ret = event->read_size;
4831 if (copy_to_user(buf, values, event->read_size))
4836 mutex_unlock(&leader->child_mutex);
4842 static int perf_read_one(struct perf_event *event,
4843 u64 read_format, char __user *buf)
4845 u64 enabled, running;
4849 values[n++] = __perf_event_read_value(event, &enabled, &running);
4850 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4851 values[n++] = enabled;
4852 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4853 values[n++] = running;
4854 if (read_format & PERF_FORMAT_ID)
4855 values[n++] = primary_event_id(event);
4857 if (copy_to_user(buf, values, n * sizeof(u64)))
4860 return n * sizeof(u64);
4863 static bool is_event_hup(struct perf_event *event)
4867 if (event->state > PERF_EVENT_STATE_EXIT)
4870 mutex_lock(&event->child_mutex);
4871 no_children = list_empty(&event->child_list);
4872 mutex_unlock(&event->child_mutex);
4877 * Read the performance event - simple non blocking version for now
4880 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4882 u64 read_format = event->attr.read_format;
4886 * Return end-of-file for a read on an event that is in
4887 * error state (i.e. because it was pinned but it couldn't be
4888 * scheduled on to the CPU at some point).
4890 if (event->state == PERF_EVENT_STATE_ERROR)
4893 if (count < event->read_size)
4896 WARN_ON_ONCE(event->ctx->parent_ctx);
4897 if (read_format & PERF_FORMAT_GROUP)
4898 ret = perf_read_group(event, read_format, buf);
4900 ret = perf_read_one(event, read_format, buf);
4906 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4908 struct perf_event *event = file->private_data;
4909 struct perf_event_context *ctx;
4912 ctx = perf_event_ctx_lock(event);
4913 ret = __perf_read(event, buf, count);
4914 perf_event_ctx_unlock(event, ctx);
4919 static __poll_t perf_poll(struct file *file, poll_table *wait)
4921 struct perf_event *event = file->private_data;
4922 struct ring_buffer *rb;
4923 __poll_t events = EPOLLHUP;
4925 poll_wait(file, &event->waitq, wait);
4927 if (is_event_hup(event))
4931 * Pin the event->rb by taking event->mmap_mutex; otherwise
4932 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4934 mutex_lock(&event->mmap_mutex);
4937 events = atomic_xchg(&rb->poll, 0);
4938 mutex_unlock(&event->mmap_mutex);
4942 static void _perf_event_reset(struct perf_event *event)
4944 (void)perf_event_read(event, false);
4945 local64_set(&event->count, 0);
4946 perf_event_update_userpage(event);
4950 * Holding the top-level event's child_mutex means that any
4951 * descendant process that has inherited this event will block
4952 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4953 * task existence requirements of perf_event_enable/disable.
4955 static void perf_event_for_each_child(struct perf_event *event,
4956 void (*func)(struct perf_event *))
4958 struct perf_event *child;
4960 WARN_ON_ONCE(event->ctx->parent_ctx);
4962 mutex_lock(&event->child_mutex);
4964 list_for_each_entry(child, &event->child_list, child_list)
4966 mutex_unlock(&event->child_mutex);
4969 static void perf_event_for_each(struct perf_event *event,
4970 void (*func)(struct perf_event *))
4972 struct perf_event_context *ctx = event->ctx;
4973 struct perf_event *sibling;
4975 lockdep_assert_held(&ctx->mutex);
4977 event = event->group_leader;
4979 perf_event_for_each_child(event, func);
4980 for_each_sibling_event(sibling, event)
4981 perf_event_for_each_child(sibling, func);
4984 static void __perf_event_period(struct perf_event *event,
4985 struct perf_cpu_context *cpuctx,
4986 struct perf_event_context *ctx,
4989 u64 value = *((u64 *)info);
4992 if (event->attr.freq) {
4993 event->attr.sample_freq = value;
4995 event->attr.sample_period = value;
4996 event->hw.sample_period = value;
4999 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5001 perf_pmu_disable(ctx->pmu);
5003 * We could be throttled; unthrottle now to avoid the tick
5004 * trying to unthrottle while we already re-started the event.
5006 if (event->hw.interrupts == MAX_INTERRUPTS) {
5007 event->hw.interrupts = 0;
5008 perf_log_throttle(event, 1);
5010 event->pmu->stop(event, PERF_EF_UPDATE);
5013 local64_set(&event->hw.period_left, 0);
5016 event->pmu->start(event, PERF_EF_RELOAD);
5017 perf_pmu_enable(ctx->pmu);
5021 static int perf_event_check_period(struct perf_event *event, u64 value)
5023 return event->pmu->check_period(event, value);
5026 static int perf_event_period(struct perf_event *event, u64 __user *arg)
5030 if (!is_sampling_event(event))
5033 if (copy_from_user(&value, arg, sizeof(value)))
5039 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5042 if (perf_event_check_period(event, value))
5045 if (!event->attr.freq && (value & (1ULL << 63)))
5048 event_function_call(event, __perf_event_period, &value);
5053 static const struct file_operations perf_fops;
5055 static inline int perf_fget_light(int fd, struct fd *p)
5057 struct fd f = fdget(fd);
5061 if (f.file->f_op != &perf_fops) {
5069 static int perf_event_set_output(struct perf_event *event,
5070 struct perf_event *output_event);
5071 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5072 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5073 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5074 struct perf_event_attr *attr);
5076 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5078 void (*func)(struct perf_event *);
5082 case PERF_EVENT_IOC_ENABLE:
5083 func = _perf_event_enable;
5085 case PERF_EVENT_IOC_DISABLE:
5086 func = _perf_event_disable;
5088 case PERF_EVENT_IOC_RESET:
5089 func = _perf_event_reset;
5092 case PERF_EVENT_IOC_REFRESH:
5093 return _perf_event_refresh(event, arg);
5095 case PERF_EVENT_IOC_PERIOD:
5096 return perf_event_period(event, (u64 __user *)arg);
5098 case PERF_EVENT_IOC_ID:
5100 u64 id = primary_event_id(event);
5102 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5107 case PERF_EVENT_IOC_SET_OUTPUT:
5111 struct perf_event *output_event;
5113 ret = perf_fget_light(arg, &output);
5116 output_event = output.file->private_data;
5117 ret = perf_event_set_output(event, output_event);
5120 ret = perf_event_set_output(event, NULL);
5125 case PERF_EVENT_IOC_SET_FILTER:
5126 return perf_event_set_filter(event, (void __user *)arg);
5128 case PERF_EVENT_IOC_SET_BPF:
5129 return perf_event_set_bpf_prog(event, arg);
5131 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5132 struct ring_buffer *rb;
5135 rb = rcu_dereference(event->rb);
5136 if (!rb || !rb->nr_pages) {
5140 rb_toggle_paused(rb, !!arg);
5145 case PERF_EVENT_IOC_QUERY_BPF:
5146 return perf_event_query_prog_array(event, (void __user *)arg);
5148 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5149 struct perf_event_attr new_attr;
5150 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5156 return perf_event_modify_attr(event, &new_attr);
5162 if (flags & PERF_IOC_FLAG_GROUP)
5163 perf_event_for_each(event, func);
5165 perf_event_for_each_child(event, func);
5170 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5172 struct perf_event *event = file->private_data;
5173 struct perf_event_context *ctx;
5176 ctx = perf_event_ctx_lock(event);
5177 ret = _perf_ioctl(event, cmd, arg);
5178 perf_event_ctx_unlock(event, ctx);
5183 #ifdef CONFIG_COMPAT
5184 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5187 switch (_IOC_NR(cmd)) {
5188 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5189 case _IOC_NR(PERF_EVENT_IOC_ID):
5190 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5191 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5192 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5193 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5194 cmd &= ~IOCSIZE_MASK;
5195 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5199 return perf_ioctl(file, cmd, arg);
5202 # define perf_compat_ioctl NULL
5205 int perf_event_task_enable(void)
5207 struct perf_event_context *ctx;
5208 struct perf_event *event;
5210 mutex_lock(¤t->perf_event_mutex);
5211 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5212 ctx = perf_event_ctx_lock(event);
5213 perf_event_for_each_child(event, _perf_event_enable);
5214 perf_event_ctx_unlock(event, ctx);
5216 mutex_unlock(¤t->perf_event_mutex);
5221 int perf_event_task_disable(void)
5223 struct perf_event_context *ctx;
5224 struct perf_event *event;
5226 mutex_lock(¤t->perf_event_mutex);
5227 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5228 ctx = perf_event_ctx_lock(event);
5229 perf_event_for_each_child(event, _perf_event_disable);
5230 perf_event_ctx_unlock(event, ctx);
5232 mutex_unlock(¤t->perf_event_mutex);
5237 static int perf_event_index(struct perf_event *event)
5239 if (event->hw.state & PERF_HES_STOPPED)
5242 if (event->state != PERF_EVENT_STATE_ACTIVE)
5245 return event->pmu->event_idx(event);
5248 static void calc_timer_values(struct perf_event *event,
5255 *now = perf_clock();
5256 ctx_time = event->shadow_ctx_time + *now;
5257 __perf_update_times(event, ctx_time, enabled, running);
5260 static void perf_event_init_userpage(struct perf_event *event)
5262 struct perf_event_mmap_page *userpg;
5263 struct ring_buffer *rb;
5266 rb = rcu_dereference(event->rb);
5270 userpg = rb->user_page;
5272 /* Allow new userspace to detect that bit 0 is deprecated */
5273 userpg->cap_bit0_is_deprecated = 1;
5274 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5275 userpg->data_offset = PAGE_SIZE;
5276 userpg->data_size = perf_data_size(rb);
5282 void __weak arch_perf_update_userpage(
5283 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5288 * Callers need to ensure there can be no nesting of this function, otherwise
5289 * the seqlock logic goes bad. We can not serialize this because the arch
5290 * code calls this from NMI context.
5292 void perf_event_update_userpage(struct perf_event *event)
5294 struct perf_event_mmap_page *userpg;
5295 struct ring_buffer *rb;
5296 u64 enabled, running, now;
5299 rb = rcu_dereference(event->rb);
5304 * compute total_time_enabled, total_time_running
5305 * based on snapshot values taken when the event
5306 * was last scheduled in.
5308 * we cannot simply called update_context_time()
5309 * because of locking issue as we can be called in
5312 calc_timer_values(event, &now, &enabled, &running);
5314 userpg = rb->user_page;
5316 * Disable preemption to guarantee consistent time stamps are stored to
5322 userpg->index = perf_event_index(event);
5323 userpg->offset = perf_event_count(event);
5325 userpg->offset -= local64_read(&event->hw.prev_count);
5327 userpg->time_enabled = enabled +
5328 atomic64_read(&event->child_total_time_enabled);
5330 userpg->time_running = running +
5331 atomic64_read(&event->child_total_time_running);
5333 arch_perf_update_userpage(event, userpg, now);
5341 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5343 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5345 struct perf_event *event = vmf->vma->vm_file->private_data;
5346 struct ring_buffer *rb;
5347 vm_fault_t ret = VM_FAULT_SIGBUS;
5349 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5350 if (vmf->pgoff == 0)
5356 rb = rcu_dereference(event->rb);
5360 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5363 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5367 get_page(vmf->page);
5368 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5369 vmf->page->index = vmf->pgoff;
5378 static void ring_buffer_attach(struct perf_event *event,
5379 struct ring_buffer *rb)
5381 struct ring_buffer *old_rb = NULL;
5382 unsigned long flags;
5386 * Should be impossible, we set this when removing
5387 * event->rb_entry and wait/clear when adding event->rb_entry.
5389 WARN_ON_ONCE(event->rcu_pending);
5392 spin_lock_irqsave(&old_rb->event_lock, flags);
5393 list_del_rcu(&event->rb_entry);
5394 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5396 event->rcu_batches = get_state_synchronize_rcu();
5397 event->rcu_pending = 1;
5401 if (event->rcu_pending) {
5402 cond_synchronize_rcu(event->rcu_batches);
5403 event->rcu_pending = 0;
5406 spin_lock_irqsave(&rb->event_lock, flags);
5407 list_add_rcu(&event->rb_entry, &rb->event_list);
5408 spin_unlock_irqrestore(&rb->event_lock, flags);
5412 * Avoid racing with perf_mmap_close(AUX): stop the event
5413 * before swizzling the event::rb pointer; if it's getting
5414 * unmapped, its aux_mmap_count will be 0 and it won't
5415 * restart. See the comment in __perf_pmu_output_stop().
5417 * Data will inevitably be lost when set_output is done in
5418 * mid-air, but then again, whoever does it like this is
5419 * not in for the data anyway.
5422 perf_event_stop(event, 0);
5424 rcu_assign_pointer(event->rb, rb);
5427 ring_buffer_put(old_rb);
5429 * Since we detached before setting the new rb, so that we
5430 * could attach the new rb, we could have missed a wakeup.
5433 wake_up_all(&event->waitq);
5437 static void ring_buffer_wakeup(struct perf_event *event)
5439 struct ring_buffer *rb;
5442 rb = rcu_dereference(event->rb);
5444 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5445 wake_up_all(&event->waitq);
5450 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5452 struct ring_buffer *rb;
5455 rb = rcu_dereference(event->rb);
5457 if (!atomic_inc_not_zero(&rb->refcount))
5465 void ring_buffer_put(struct ring_buffer *rb)
5467 if (!atomic_dec_and_test(&rb->refcount))
5470 WARN_ON_ONCE(!list_empty(&rb->event_list));
5472 call_rcu(&rb->rcu_head, rb_free_rcu);
5475 static void perf_mmap_open(struct vm_area_struct *vma)
5477 struct perf_event *event = vma->vm_file->private_data;
5479 atomic_inc(&event->mmap_count);
5480 atomic_inc(&event->rb->mmap_count);
5483 atomic_inc(&event->rb->aux_mmap_count);
5485 if (event->pmu->event_mapped)
5486 event->pmu->event_mapped(event, vma->vm_mm);
5489 static void perf_pmu_output_stop(struct perf_event *event);
5492 * A buffer can be mmap()ed multiple times; either directly through the same
5493 * event, or through other events by use of perf_event_set_output().
5495 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5496 * the buffer here, where we still have a VM context. This means we need
5497 * to detach all events redirecting to us.
5499 static void perf_mmap_close(struct vm_area_struct *vma)
5501 struct perf_event *event = vma->vm_file->private_data;
5502 struct ring_buffer *rb = ring_buffer_get(event);
5503 struct user_struct *mmap_user = rb->mmap_user;
5504 int mmap_locked = rb->mmap_locked;
5505 unsigned long size = perf_data_size(rb);
5506 bool detach_rest = false;
5508 if (event->pmu->event_unmapped)
5509 event->pmu->event_unmapped(event, vma->vm_mm);
5512 * rb->aux_mmap_count will always drop before rb->mmap_count and
5513 * event->mmap_count, so it is ok to use event->mmap_mutex to
5514 * serialize with perf_mmap here.
5516 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5517 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5519 * Stop all AUX events that are writing to this buffer,
5520 * so that we can free its AUX pages and corresponding PMU
5521 * data. Note that after rb::aux_mmap_count dropped to zero,
5522 * they won't start any more (see perf_aux_output_begin()).
5524 perf_pmu_output_stop(event);
5526 /* now it's safe to free the pages */
5527 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5528 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5530 /* this has to be the last one */
5532 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5534 mutex_unlock(&event->mmap_mutex);
5537 if (atomic_dec_and_test(&rb->mmap_count))
5540 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5543 ring_buffer_attach(event, NULL);
5544 mutex_unlock(&event->mmap_mutex);
5546 /* If there's still other mmap()s of this buffer, we're done. */
5551 * No other mmap()s, detach from all other events that might redirect
5552 * into the now unreachable buffer. Somewhat complicated by the
5553 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5557 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5558 if (!atomic_long_inc_not_zero(&event->refcount)) {
5560 * This event is en-route to free_event() which will
5561 * detach it and remove it from the list.
5567 mutex_lock(&event->mmap_mutex);
5569 * Check we didn't race with perf_event_set_output() which can
5570 * swizzle the rb from under us while we were waiting to
5571 * acquire mmap_mutex.
5573 * If we find a different rb; ignore this event, a next
5574 * iteration will no longer find it on the list. We have to
5575 * still restart the iteration to make sure we're not now
5576 * iterating the wrong list.
5578 if (event->rb == rb)
5579 ring_buffer_attach(event, NULL);
5581 mutex_unlock(&event->mmap_mutex);
5585 * Restart the iteration; either we're on the wrong list or
5586 * destroyed its integrity by doing a deletion.
5593 * It could be there's still a few 0-ref events on the list; they'll
5594 * get cleaned up by free_event() -- they'll also still have their
5595 * ref on the rb and will free it whenever they are done with it.
5597 * Aside from that, this buffer is 'fully' detached and unmapped,
5598 * undo the VM accounting.
5601 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5602 vma->vm_mm->pinned_vm -= mmap_locked;
5603 free_uid(mmap_user);
5606 ring_buffer_put(rb); /* could be last */
5609 static const struct vm_operations_struct perf_mmap_vmops = {
5610 .open = perf_mmap_open,
5611 .close = perf_mmap_close, /* non mergable */
5612 .fault = perf_mmap_fault,
5613 .page_mkwrite = perf_mmap_fault,
5616 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5618 struct perf_event *event = file->private_data;
5619 unsigned long user_locked, user_lock_limit;
5620 struct user_struct *user = current_user();
5621 unsigned long locked, lock_limit;
5622 struct ring_buffer *rb = NULL;
5623 unsigned long vma_size;
5624 unsigned long nr_pages;
5625 long user_extra = 0, extra = 0;
5626 int ret = 0, flags = 0;
5629 * Don't allow mmap() of inherited per-task counters. This would
5630 * create a performance issue due to all children writing to the
5633 if (event->cpu == -1 && event->attr.inherit)
5636 if (!(vma->vm_flags & VM_SHARED))
5639 vma_size = vma->vm_end - vma->vm_start;
5641 if (vma->vm_pgoff == 0) {
5642 nr_pages = (vma_size / PAGE_SIZE) - 1;
5645 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5646 * mapped, all subsequent mappings should have the same size
5647 * and offset. Must be above the normal perf buffer.
5649 u64 aux_offset, aux_size;
5654 nr_pages = vma_size / PAGE_SIZE;
5656 mutex_lock(&event->mmap_mutex);
5663 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5664 aux_size = READ_ONCE(rb->user_page->aux_size);
5666 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5669 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5672 /* already mapped with a different offset */
5673 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5676 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5679 /* already mapped with a different size */
5680 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5683 if (!is_power_of_2(nr_pages))
5686 if (!atomic_inc_not_zero(&rb->mmap_count))
5689 if (rb_has_aux(rb)) {
5690 atomic_inc(&rb->aux_mmap_count);
5695 atomic_set(&rb->aux_mmap_count, 1);
5696 user_extra = nr_pages;
5702 * If we have rb pages ensure they're a power-of-two number, so we
5703 * can do bitmasks instead of modulo.
5705 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5708 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5711 WARN_ON_ONCE(event->ctx->parent_ctx);
5713 mutex_lock(&event->mmap_mutex);
5715 if (event->rb->nr_pages != nr_pages) {
5720 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5722 * Raced against perf_mmap_close() through
5723 * perf_event_set_output(). Try again, hope for better
5726 mutex_unlock(&event->mmap_mutex);
5733 user_extra = nr_pages + 1;
5736 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5739 * Increase the limit linearly with more CPUs:
5741 user_lock_limit *= num_online_cpus();
5743 user_locked = atomic_long_read(&user->locked_vm);
5746 * sysctl_perf_event_mlock may have changed, so that
5747 * user->locked_vm > user_lock_limit
5749 if (user_locked > user_lock_limit)
5750 user_locked = user_lock_limit;
5751 user_locked += user_extra;
5753 if (user_locked > user_lock_limit)
5754 extra = user_locked - user_lock_limit;
5756 lock_limit = rlimit(RLIMIT_MEMLOCK);
5757 lock_limit >>= PAGE_SHIFT;
5758 locked = vma->vm_mm->pinned_vm + extra;
5760 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5761 !capable(CAP_IPC_LOCK)) {
5766 WARN_ON(!rb && event->rb);
5768 if (vma->vm_flags & VM_WRITE)
5769 flags |= RING_BUFFER_WRITABLE;
5772 rb = rb_alloc(nr_pages,
5773 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5781 atomic_set(&rb->mmap_count, 1);
5782 rb->mmap_user = get_current_user();
5783 rb->mmap_locked = extra;
5785 ring_buffer_attach(event, rb);
5787 perf_event_init_userpage(event);
5788 perf_event_update_userpage(event);
5790 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5791 event->attr.aux_watermark, flags);
5793 rb->aux_mmap_locked = extra;
5798 atomic_long_add(user_extra, &user->locked_vm);
5799 vma->vm_mm->pinned_vm += extra;
5801 atomic_inc(&event->mmap_count);
5803 atomic_dec(&rb->mmap_count);
5806 mutex_unlock(&event->mmap_mutex);
5809 * Since pinned accounting is per vm we cannot allow fork() to copy our
5812 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5813 vma->vm_ops = &perf_mmap_vmops;
5815 if (event->pmu->event_mapped)
5816 event->pmu->event_mapped(event, vma->vm_mm);
5821 static int perf_fasync(int fd, struct file *filp, int on)
5823 struct inode *inode = file_inode(filp);
5824 struct perf_event *event = filp->private_data;
5828 retval = fasync_helper(fd, filp, on, &event->fasync);
5829 inode_unlock(inode);
5837 static const struct file_operations perf_fops = {
5838 .llseek = no_llseek,
5839 .release = perf_release,
5842 .unlocked_ioctl = perf_ioctl,
5843 .compat_ioctl = perf_compat_ioctl,
5845 .fasync = perf_fasync,
5851 * If there's data, ensure we set the poll() state and publish everything
5852 * to user-space before waking everybody up.
5855 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5857 /* only the parent has fasync state */
5859 event = event->parent;
5860 return &event->fasync;
5863 void perf_event_wakeup(struct perf_event *event)
5865 ring_buffer_wakeup(event);
5867 if (event->pending_kill) {
5868 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5869 event->pending_kill = 0;
5873 static void perf_pending_event_disable(struct perf_event *event)
5875 int cpu = READ_ONCE(event->pending_disable);
5880 if (cpu == smp_processor_id()) {
5881 WRITE_ONCE(event->pending_disable, -1);
5882 perf_event_disable_local(event);
5889 * perf_event_disable_inatomic()
5890 * @pending_disable = CPU-A;
5894 * @pending_disable = -1;
5897 * perf_event_disable_inatomic()
5898 * @pending_disable = CPU-B;
5899 * irq_work_queue(); // FAILS
5902 * perf_pending_event()
5904 * But the event runs on CPU-B and wants disabling there.
5906 irq_work_queue_on(&event->pending, cpu);
5909 static void perf_pending_event(struct irq_work *entry)
5911 struct perf_event *event = container_of(entry, struct perf_event, pending);
5914 rctx = perf_swevent_get_recursion_context();
5916 * If we 'fail' here, that's OK, it means recursion is already disabled
5917 * and we won't recurse 'further'.
5920 perf_pending_event_disable(event);
5922 if (event->pending_wakeup) {
5923 event->pending_wakeup = 0;
5924 perf_event_wakeup(event);
5928 perf_swevent_put_recursion_context(rctx);
5932 * We assume there is only KVM supporting the callbacks.
5933 * Later on, we might change it to a list if there is
5934 * another virtualization implementation supporting the callbacks.
5936 struct perf_guest_info_callbacks *perf_guest_cbs;
5938 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5940 perf_guest_cbs = cbs;
5943 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5945 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5947 perf_guest_cbs = NULL;
5950 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5953 perf_output_sample_regs(struct perf_output_handle *handle,
5954 struct pt_regs *regs, u64 mask)
5957 DECLARE_BITMAP(_mask, 64);
5959 bitmap_from_u64(_mask, mask);
5960 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5963 val = perf_reg_value(regs, bit);
5964 perf_output_put(handle, val);
5968 static void perf_sample_regs_user(struct perf_regs *regs_user,
5969 struct pt_regs *regs,
5970 struct pt_regs *regs_user_copy)
5972 if (user_mode(regs)) {
5973 regs_user->abi = perf_reg_abi(current);
5974 regs_user->regs = regs;
5975 } else if (!(current->flags & PF_KTHREAD)) {
5976 perf_get_regs_user(regs_user, regs, regs_user_copy);
5978 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5979 regs_user->regs = NULL;
5983 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5984 struct pt_regs *regs)
5986 regs_intr->regs = regs;
5987 regs_intr->abi = perf_reg_abi(current);
5992 * Get remaining task size from user stack pointer.
5994 * It'd be better to take stack vma map and limit this more
5995 * precisly, but there's no way to get it safely under interrupt,
5996 * so using TASK_SIZE as limit.
5998 static u64 perf_ustack_task_size(struct pt_regs *regs)
6000 unsigned long addr = perf_user_stack_pointer(regs);
6002 if (!addr || addr >= TASK_SIZE)
6005 return TASK_SIZE - addr;
6009 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6010 struct pt_regs *regs)
6014 /* No regs, no stack pointer, no dump. */
6019 * Check if we fit in with the requested stack size into the:
6021 * If we don't, we limit the size to the TASK_SIZE.
6023 * - remaining sample size
6024 * If we don't, we customize the stack size to
6025 * fit in to the remaining sample size.
6028 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6029 stack_size = min(stack_size, (u16) task_size);
6031 /* Current header size plus static size and dynamic size. */
6032 header_size += 2 * sizeof(u64);
6034 /* Do we fit in with the current stack dump size? */
6035 if ((u16) (header_size + stack_size) < header_size) {
6037 * If we overflow the maximum size for the sample,
6038 * we customize the stack dump size to fit in.
6040 stack_size = USHRT_MAX - header_size - sizeof(u64);
6041 stack_size = round_up(stack_size, sizeof(u64));
6048 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6049 struct pt_regs *regs)
6051 /* Case of a kernel thread, nothing to dump */
6054 perf_output_put(handle, size);
6064 * - the size requested by user or the best one we can fit
6065 * in to the sample max size
6067 * - user stack dump data
6069 * - the actual dumped size
6073 perf_output_put(handle, dump_size);
6076 sp = perf_user_stack_pointer(regs);
6079 rem = __output_copy_user(handle, (void *) sp, dump_size);
6081 dyn_size = dump_size - rem;
6083 perf_output_skip(handle, rem);
6086 perf_output_put(handle, dyn_size);
6090 static void __perf_event_header__init_id(struct perf_event_header *header,
6091 struct perf_sample_data *data,
6092 struct perf_event *event)
6094 u64 sample_type = event->attr.sample_type;
6096 data->type = sample_type;
6097 header->size += event->id_header_size;
6099 if (sample_type & PERF_SAMPLE_TID) {
6100 /* namespace issues */
6101 data->tid_entry.pid = perf_event_pid(event, current);
6102 data->tid_entry.tid = perf_event_tid(event, current);
6105 if (sample_type & PERF_SAMPLE_TIME)
6106 data->time = perf_event_clock(event);
6108 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6109 data->id = primary_event_id(event);
6111 if (sample_type & PERF_SAMPLE_STREAM_ID)
6112 data->stream_id = event->id;
6114 if (sample_type & PERF_SAMPLE_CPU) {
6115 data->cpu_entry.cpu = raw_smp_processor_id();
6116 data->cpu_entry.reserved = 0;
6120 void perf_event_header__init_id(struct perf_event_header *header,
6121 struct perf_sample_data *data,
6122 struct perf_event *event)
6124 if (event->attr.sample_id_all)
6125 __perf_event_header__init_id(header, data, event);
6128 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6129 struct perf_sample_data *data)
6131 u64 sample_type = data->type;
6133 if (sample_type & PERF_SAMPLE_TID)
6134 perf_output_put(handle, data->tid_entry);
6136 if (sample_type & PERF_SAMPLE_TIME)
6137 perf_output_put(handle, data->time);
6139 if (sample_type & PERF_SAMPLE_ID)
6140 perf_output_put(handle, data->id);
6142 if (sample_type & PERF_SAMPLE_STREAM_ID)
6143 perf_output_put(handle, data->stream_id);
6145 if (sample_type & PERF_SAMPLE_CPU)
6146 perf_output_put(handle, data->cpu_entry);
6148 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6149 perf_output_put(handle, data->id);
6152 void perf_event__output_id_sample(struct perf_event *event,
6153 struct perf_output_handle *handle,
6154 struct perf_sample_data *sample)
6156 if (event->attr.sample_id_all)
6157 __perf_event__output_id_sample(handle, sample);
6160 static void perf_output_read_one(struct perf_output_handle *handle,
6161 struct perf_event *event,
6162 u64 enabled, u64 running)
6164 u64 read_format = event->attr.read_format;
6168 values[n++] = perf_event_count(event);
6169 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6170 values[n++] = enabled +
6171 atomic64_read(&event->child_total_time_enabled);
6173 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6174 values[n++] = running +
6175 atomic64_read(&event->child_total_time_running);
6177 if (read_format & PERF_FORMAT_ID)
6178 values[n++] = primary_event_id(event);
6180 __output_copy(handle, values, n * sizeof(u64));
6183 static void perf_output_read_group(struct perf_output_handle *handle,
6184 struct perf_event *event,
6185 u64 enabled, u64 running)
6187 struct perf_event *leader = event->group_leader, *sub;
6188 u64 read_format = event->attr.read_format;
6192 values[n++] = 1 + leader->nr_siblings;
6194 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6195 values[n++] = enabled;
6197 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6198 values[n++] = running;
6200 if ((leader != event) &&
6201 (leader->state == PERF_EVENT_STATE_ACTIVE))
6202 leader->pmu->read(leader);
6204 values[n++] = perf_event_count(leader);
6205 if (read_format & PERF_FORMAT_ID)
6206 values[n++] = primary_event_id(leader);
6208 __output_copy(handle, values, n * sizeof(u64));
6210 for_each_sibling_event(sub, leader) {
6213 if ((sub != event) &&
6214 (sub->state == PERF_EVENT_STATE_ACTIVE))
6215 sub->pmu->read(sub);
6217 values[n++] = perf_event_count(sub);
6218 if (read_format & PERF_FORMAT_ID)
6219 values[n++] = primary_event_id(sub);
6221 __output_copy(handle, values, n * sizeof(u64));
6225 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6226 PERF_FORMAT_TOTAL_TIME_RUNNING)
6229 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6231 * The problem is that its both hard and excessively expensive to iterate the
6232 * child list, not to mention that its impossible to IPI the children running
6233 * on another CPU, from interrupt/NMI context.
6235 static void perf_output_read(struct perf_output_handle *handle,
6236 struct perf_event *event)
6238 u64 enabled = 0, running = 0, now;
6239 u64 read_format = event->attr.read_format;
6242 * compute total_time_enabled, total_time_running
6243 * based on snapshot values taken when the event
6244 * was last scheduled in.
6246 * we cannot simply called update_context_time()
6247 * because of locking issue as we are called in
6250 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6251 calc_timer_values(event, &now, &enabled, &running);
6253 if (event->attr.read_format & PERF_FORMAT_GROUP)
6254 perf_output_read_group(handle, event, enabled, running);
6256 perf_output_read_one(handle, event, enabled, running);
6259 void perf_output_sample(struct perf_output_handle *handle,
6260 struct perf_event_header *header,
6261 struct perf_sample_data *data,
6262 struct perf_event *event)
6264 u64 sample_type = data->type;
6266 perf_output_put(handle, *header);
6268 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6269 perf_output_put(handle, data->id);
6271 if (sample_type & PERF_SAMPLE_IP)
6272 perf_output_put(handle, data->ip);
6274 if (sample_type & PERF_SAMPLE_TID)
6275 perf_output_put(handle, data->tid_entry);
6277 if (sample_type & PERF_SAMPLE_TIME)
6278 perf_output_put(handle, data->time);
6280 if (sample_type & PERF_SAMPLE_ADDR)
6281 perf_output_put(handle, data->addr);
6283 if (sample_type & PERF_SAMPLE_ID)
6284 perf_output_put(handle, data->id);
6286 if (sample_type & PERF_SAMPLE_STREAM_ID)
6287 perf_output_put(handle, data->stream_id);
6289 if (sample_type & PERF_SAMPLE_CPU)
6290 perf_output_put(handle, data->cpu_entry);
6292 if (sample_type & PERF_SAMPLE_PERIOD)
6293 perf_output_put(handle, data->period);
6295 if (sample_type & PERF_SAMPLE_READ)
6296 perf_output_read(handle, event);
6298 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6301 size += data->callchain->nr;
6302 size *= sizeof(u64);
6303 __output_copy(handle, data->callchain, size);
6306 if (sample_type & PERF_SAMPLE_RAW) {
6307 struct perf_raw_record *raw = data->raw;
6310 struct perf_raw_frag *frag = &raw->frag;
6312 perf_output_put(handle, raw->size);
6315 __output_custom(handle, frag->copy,
6316 frag->data, frag->size);
6318 __output_copy(handle, frag->data,
6321 if (perf_raw_frag_last(frag))
6326 __output_skip(handle, NULL, frag->pad);
6332 .size = sizeof(u32),
6335 perf_output_put(handle, raw);
6339 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6340 if (data->br_stack) {
6343 size = data->br_stack->nr
6344 * sizeof(struct perf_branch_entry);
6346 perf_output_put(handle, data->br_stack->nr);
6347 perf_output_copy(handle, data->br_stack->entries, size);
6350 * we always store at least the value of nr
6353 perf_output_put(handle, nr);
6357 if (sample_type & PERF_SAMPLE_REGS_USER) {
6358 u64 abi = data->regs_user.abi;
6361 * If there are no regs to dump, notice it through
6362 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6364 perf_output_put(handle, abi);
6367 u64 mask = event->attr.sample_regs_user;
6368 perf_output_sample_regs(handle,
6369 data->regs_user.regs,
6374 if (sample_type & PERF_SAMPLE_STACK_USER) {
6375 perf_output_sample_ustack(handle,
6376 data->stack_user_size,
6377 data->regs_user.regs);
6380 if (sample_type & PERF_SAMPLE_WEIGHT)
6381 perf_output_put(handle, data->weight);
6383 if (sample_type & PERF_SAMPLE_DATA_SRC)
6384 perf_output_put(handle, data->data_src.val);
6386 if (sample_type & PERF_SAMPLE_TRANSACTION)
6387 perf_output_put(handle, data->txn);
6389 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6390 u64 abi = data->regs_intr.abi;
6392 * If there are no regs to dump, notice it through
6393 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6395 perf_output_put(handle, abi);
6398 u64 mask = event->attr.sample_regs_intr;
6400 perf_output_sample_regs(handle,
6401 data->regs_intr.regs,
6406 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6407 perf_output_put(handle, data->phys_addr);
6409 if (!event->attr.watermark) {
6410 int wakeup_events = event->attr.wakeup_events;
6412 if (wakeup_events) {
6413 struct ring_buffer *rb = handle->rb;
6414 int events = local_inc_return(&rb->events);
6416 if (events >= wakeup_events) {
6417 local_sub(wakeup_events, &rb->events);
6418 local_inc(&rb->wakeup);
6424 static u64 perf_virt_to_phys(u64 virt)
6431 if (virt >= TASK_SIZE) {
6432 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6433 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6434 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6435 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6438 * Walking the pages tables for user address.
6439 * Interrupts are disabled, so it prevents any tear down
6440 * of the page tables.
6441 * Try IRQ-safe __get_user_pages_fast first.
6442 * If failed, leave phys_addr as 0.
6444 if (current->mm != NULL) {
6447 pagefault_disable();
6448 if (__get_user_pages_fast(virt, 1, 0, &p) == 1) {
6449 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6459 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6461 struct perf_callchain_entry *
6462 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6464 bool kernel = !event->attr.exclude_callchain_kernel;
6465 bool user = !event->attr.exclude_callchain_user;
6466 /* Disallow cross-task user callchains. */
6467 bool crosstask = event->ctx->task && event->ctx->task != current;
6468 const u32 max_stack = event->attr.sample_max_stack;
6469 struct perf_callchain_entry *callchain;
6471 if (!kernel && !user)
6472 return &__empty_callchain;
6474 callchain = get_perf_callchain(regs, 0, kernel, user,
6475 max_stack, crosstask, true);
6476 return callchain ?: &__empty_callchain;
6479 void perf_prepare_sample(struct perf_event_header *header,
6480 struct perf_sample_data *data,
6481 struct perf_event *event,
6482 struct pt_regs *regs)
6484 u64 sample_type = event->attr.sample_type;
6486 header->type = PERF_RECORD_SAMPLE;
6487 header->size = sizeof(*header) + event->header_size;
6490 header->misc |= perf_misc_flags(regs);
6492 __perf_event_header__init_id(header, data, event);
6494 if (sample_type & PERF_SAMPLE_IP)
6495 data->ip = perf_instruction_pointer(regs);
6497 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6500 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6501 data->callchain = perf_callchain(event, regs);
6503 size += data->callchain->nr;
6505 header->size += size * sizeof(u64);
6508 if (sample_type & PERF_SAMPLE_RAW) {
6509 struct perf_raw_record *raw = data->raw;
6513 struct perf_raw_frag *frag = &raw->frag;
6518 if (perf_raw_frag_last(frag))
6523 size = round_up(sum + sizeof(u32), sizeof(u64));
6524 raw->size = size - sizeof(u32);
6525 frag->pad = raw->size - sum;
6530 header->size += size;
6533 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6534 int size = sizeof(u64); /* nr */
6535 if (data->br_stack) {
6536 size += data->br_stack->nr
6537 * sizeof(struct perf_branch_entry);
6539 header->size += size;
6542 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6543 perf_sample_regs_user(&data->regs_user, regs,
6544 &data->regs_user_copy);
6546 if (sample_type & PERF_SAMPLE_REGS_USER) {
6547 /* regs dump ABI info */
6548 int size = sizeof(u64);
6550 if (data->regs_user.regs) {
6551 u64 mask = event->attr.sample_regs_user;
6552 size += hweight64(mask) * sizeof(u64);
6555 header->size += size;
6558 if (sample_type & PERF_SAMPLE_STACK_USER) {
6560 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6561 * processed as the last one or have additional check added
6562 * in case new sample type is added, because we could eat
6563 * up the rest of the sample size.
6565 u16 stack_size = event->attr.sample_stack_user;
6566 u16 size = sizeof(u64);
6568 stack_size = perf_sample_ustack_size(stack_size, header->size,
6569 data->regs_user.regs);
6572 * If there is something to dump, add space for the dump
6573 * itself and for the field that tells the dynamic size,
6574 * which is how many have been actually dumped.
6577 size += sizeof(u64) + stack_size;
6579 data->stack_user_size = stack_size;
6580 header->size += size;
6583 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6584 /* regs dump ABI info */
6585 int size = sizeof(u64);
6587 perf_sample_regs_intr(&data->regs_intr, regs);
6589 if (data->regs_intr.regs) {
6590 u64 mask = event->attr.sample_regs_intr;
6592 size += hweight64(mask) * sizeof(u64);
6595 header->size += size;
6598 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6599 data->phys_addr = perf_virt_to_phys(data->addr);
6602 static __always_inline void
6603 __perf_event_output(struct perf_event *event,
6604 struct perf_sample_data *data,
6605 struct pt_regs *regs,
6606 int (*output_begin)(struct perf_output_handle *,
6607 struct perf_event *,
6610 struct perf_output_handle handle;
6611 struct perf_event_header header;
6613 /* protect the callchain buffers */
6616 perf_prepare_sample(&header, data, event, regs);
6618 if (output_begin(&handle, event, header.size))
6621 perf_output_sample(&handle, &header, data, event);
6623 perf_output_end(&handle);
6630 perf_event_output_forward(struct perf_event *event,
6631 struct perf_sample_data *data,
6632 struct pt_regs *regs)
6634 __perf_event_output(event, data, regs, perf_output_begin_forward);
6638 perf_event_output_backward(struct perf_event *event,
6639 struct perf_sample_data *data,
6640 struct pt_regs *regs)
6642 __perf_event_output(event, data, regs, perf_output_begin_backward);
6646 perf_event_output(struct perf_event *event,
6647 struct perf_sample_data *data,
6648 struct pt_regs *regs)
6650 __perf_event_output(event, data, regs, perf_output_begin);
6657 struct perf_read_event {
6658 struct perf_event_header header;
6665 perf_event_read_event(struct perf_event *event,
6666 struct task_struct *task)
6668 struct perf_output_handle handle;
6669 struct perf_sample_data sample;
6670 struct perf_read_event read_event = {
6672 .type = PERF_RECORD_READ,
6674 .size = sizeof(read_event) + event->read_size,
6676 .pid = perf_event_pid(event, task),
6677 .tid = perf_event_tid(event, task),
6681 perf_event_header__init_id(&read_event.header, &sample, event);
6682 ret = perf_output_begin(&handle, event, read_event.header.size);
6686 perf_output_put(&handle, read_event);
6687 perf_output_read(&handle, event);
6688 perf_event__output_id_sample(event, &handle, &sample);
6690 perf_output_end(&handle);
6693 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6696 perf_iterate_ctx(struct perf_event_context *ctx,
6697 perf_iterate_f output,
6698 void *data, bool all)
6700 struct perf_event *event;
6702 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6704 if (event->state < PERF_EVENT_STATE_INACTIVE)
6706 if (!event_filter_match(event))
6710 output(event, data);
6714 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6716 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6717 struct perf_event *event;
6719 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6721 * Skip events that are not fully formed yet; ensure that
6722 * if we observe event->ctx, both event and ctx will be
6723 * complete enough. See perf_install_in_context().
6725 if (!smp_load_acquire(&event->ctx))
6728 if (event->state < PERF_EVENT_STATE_INACTIVE)
6730 if (!event_filter_match(event))
6732 output(event, data);
6737 * Iterate all events that need to receive side-band events.
6739 * For new callers; ensure that account_pmu_sb_event() includes
6740 * your event, otherwise it might not get delivered.
6743 perf_iterate_sb(perf_iterate_f output, void *data,
6744 struct perf_event_context *task_ctx)
6746 struct perf_event_context *ctx;
6753 * If we have task_ctx != NULL we only notify the task context itself.
6754 * The task_ctx is set only for EXIT events before releasing task
6758 perf_iterate_ctx(task_ctx, output, data, false);
6762 perf_iterate_sb_cpu(output, data);
6764 for_each_task_context_nr(ctxn) {
6765 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6767 perf_iterate_ctx(ctx, output, data, false);
6775 * Clear all file-based filters at exec, they'll have to be
6776 * re-instated when/if these objects are mmapped again.
6778 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6780 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6781 struct perf_addr_filter *filter;
6782 unsigned int restart = 0, count = 0;
6783 unsigned long flags;
6785 if (!has_addr_filter(event))
6788 raw_spin_lock_irqsave(&ifh->lock, flags);
6789 list_for_each_entry(filter, &ifh->list, entry) {
6790 if (filter->path.dentry) {
6791 event->addr_filter_ranges[count].start = 0;
6792 event->addr_filter_ranges[count].size = 0;
6800 event->addr_filters_gen++;
6801 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6804 perf_event_stop(event, 1);
6807 void perf_event_exec(void)
6809 struct perf_event_context *ctx;
6813 for_each_task_context_nr(ctxn) {
6814 ctx = current->perf_event_ctxp[ctxn];
6818 perf_event_enable_on_exec(ctxn);
6820 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6826 struct remote_output {
6827 struct ring_buffer *rb;
6831 static void __perf_event_output_stop(struct perf_event *event, void *data)
6833 struct perf_event *parent = event->parent;
6834 struct remote_output *ro = data;
6835 struct ring_buffer *rb = ro->rb;
6836 struct stop_event_data sd = {
6840 if (!has_aux(event))
6847 * In case of inheritance, it will be the parent that links to the
6848 * ring-buffer, but it will be the child that's actually using it.
6850 * We are using event::rb to determine if the event should be stopped,
6851 * however this may race with ring_buffer_attach() (through set_output),
6852 * which will make us skip the event that actually needs to be stopped.
6853 * So ring_buffer_attach() has to stop an aux event before re-assigning
6856 if (rcu_dereference(parent->rb) == rb)
6857 ro->err = __perf_event_stop(&sd);
6860 static int __perf_pmu_output_stop(void *info)
6862 struct perf_event *event = info;
6863 struct pmu *pmu = event->ctx->pmu;
6864 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6865 struct remote_output ro = {
6870 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6871 if (cpuctx->task_ctx)
6872 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6879 static void perf_pmu_output_stop(struct perf_event *event)
6881 struct perf_event *iter;
6886 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6888 * For per-CPU events, we need to make sure that neither they
6889 * nor their children are running; for cpu==-1 events it's
6890 * sufficient to stop the event itself if it's active, since
6891 * it can't have children.
6895 cpu = READ_ONCE(iter->oncpu);
6900 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6901 if (err == -EAGAIN) {
6910 * task tracking -- fork/exit
6912 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6915 struct perf_task_event {
6916 struct task_struct *task;
6917 struct perf_event_context *task_ctx;
6920 struct perf_event_header header;
6930 static int perf_event_task_match(struct perf_event *event)
6932 return event->attr.comm || event->attr.mmap ||
6933 event->attr.mmap2 || event->attr.mmap_data ||
6937 static void perf_event_task_output(struct perf_event *event,
6940 struct perf_task_event *task_event = data;
6941 struct perf_output_handle handle;
6942 struct perf_sample_data sample;
6943 struct task_struct *task = task_event->task;
6944 int ret, size = task_event->event_id.header.size;
6946 if (!perf_event_task_match(event))
6949 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6951 ret = perf_output_begin(&handle, event,
6952 task_event->event_id.header.size);
6956 task_event->event_id.pid = perf_event_pid(event, task);
6957 task_event->event_id.tid = perf_event_tid(event, task);
6959 if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
6960 task_event->event_id.ppid = perf_event_pid(event,
6962 task_event->event_id.ptid = perf_event_pid(event,
6964 } else { /* PERF_RECORD_FORK */
6965 task_event->event_id.ppid = perf_event_pid(event, current);
6966 task_event->event_id.ptid = perf_event_tid(event, current);
6969 task_event->event_id.time = perf_event_clock(event);
6971 perf_output_put(&handle, task_event->event_id);
6973 perf_event__output_id_sample(event, &handle, &sample);
6975 perf_output_end(&handle);
6977 task_event->event_id.header.size = size;
6980 static void perf_event_task(struct task_struct *task,
6981 struct perf_event_context *task_ctx,
6984 struct perf_task_event task_event;
6986 if (!atomic_read(&nr_comm_events) &&
6987 !atomic_read(&nr_mmap_events) &&
6988 !atomic_read(&nr_task_events))
6991 task_event = (struct perf_task_event){
6993 .task_ctx = task_ctx,
6996 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6998 .size = sizeof(task_event.event_id),
7008 perf_iterate_sb(perf_event_task_output,
7013 void perf_event_fork(struct task_struct *task)
7015 perf_event_task(task, NULL, 1);
7016 perf_event_namespaces(task);
7023 struct perf_comm_event {
7024 struct task_struct *task;
7029 struct perf_event_header header;
7036 static int perf_event_comm_match(struct perf_event *event)
7038 return event->attr.comm;
7041 static void perf_event_comm_output(struct perf_event *event,
7044 struct perf_comm_event *comm_event = data;
7045 struct perf_output_handle handle;
7046 struct perf_sample_data sample;
7047 int size = comm_event->event_id.header.size;
7050 if (!perf_event_comm_match(event))
7053 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7054 ret = perf_output_begin(&handle, event,
7055 comm_event->event_id.header.size);
7060 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7061 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7063 perf_output_put(&handle, comm_event->event_id);
7064 __output_copy(&handle, comm_event->comm,
7065 comm_event->comm_size);
7067 perf_event__output_id_sample(event, &handle, &sample);
7069 perf_output_end(&handle);
7071 comm_event->event_id.header.size = size;
7074 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7076 char comm[TASK_COMM_LEN];
7079 memset(comm, 0, sizeof(comm));
7080 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7081 size = ALIGN(strlen(comm)+1, sizeof(u64));
7083 comm_event->comm = comm;
7084 comm_event->comm_size = size;
7086 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7088 perf_iterate_sb(perf_event_comm_output,
7093 void perf_event_comm(struct task_struct *task, bool exec)
7095 struct perf_comm_event comm_event;
7097 if (!atomic_read(&nr_comm_events))
7100 comm_event = (struct perf_comm_event){
7106 .type = PERF_RECORD_COMM,
7107 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7115 perf_event_comm_event(&comm_event);
7119 * namespaces tracking
7122 struct perf_namespaces_event {
7123 struct task_struct *task;
7126 struct perf_event_header header;
7131 struct perf_ns_link_info link_info[NR_NAMESPACES];
7135 static int perf_event_namespaces_match(struct perf_event *event)
7137 return event->attr.namespaces;
7140 static void perf_event_namespaces_output(struct perf_event *event,
7143 struct perf_namespaces_event *namespaces_event = data;
7144 struct perf_output_handle handle;
7145 struct perf_sample_data sample;
7146 u16 header_size = namespaces_event->event_id.header.size;
7149 if (!perf_event_namespaces_match(event))
7152 perf_event_header__init_id(&namespaces_event->event_id.header,
7154 ret = perf_output_begin(&handle, event,
7155 namespaces_event->event_id.header.size);
7159 namespaces_event->event_id.pid = perf_event_pid(event,
7160 namespaces_event->task);
7161 namespaces_event->event_id.tid = perf_event_tid(event,
7162 namespaces_event->task);
7164 perf_output_put(&handle, namespaces_event->event_id);
7166 perf_event__output_id_sample(event, &handle, &sample);
7168 perf_output_end(&handle);
7170 namespaces_event->event_id.header.size = header_size;
7173 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7174 struct task_struct *task,
7175 const struct proc_ns_operations *ns_ops)
7177 struct path ns_path;
7178 struct inode *ns_inode;
7181 error = ns_get_path(&ns_path, task, ns_ops);
7183 ns_inode = ns_path.dentry->d_inode;
7184 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7185 ns_link_info->ino = ns_inode->i_ino;
7190 void perf_event_namespaces(struct task_struct *task)
7192 struct perf_namespaces_event namespaces_event;
7193 struct perf_ns_link_info *ns_link_info;
7195 if (!atomic_read(&nr_namespaces_events))
7198 namespaces_event = (struct perf_namespaces_event){
7202 .type = PERF_RECORD_NAMESPACES,
7204 .size = sizeof(namespaces_event.event_id),
7208 .nr_namespaces = NR_NAMESPACES,
7209 /* .link_info[NR_NAMESPACES] */
7213 ns_link_info = namespaces_event.event_id.link_info;
7215 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7216 task, &mntns_operations);
7218 #ifdef CONFIG_USER_NS
7219 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7220 task, &userns_operations);
7222 #ifdef CONFIG_NET_NS
7223 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7224 task, &netns_operations);
7226 #ifdef CONFIG_UTS_NS
7227 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7228 task, &utsns_operations);
7230 #ifdef CONFIG_IPC_NS
7231 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7232 task, &ipcns_operations);
7234 #ifdef CONFIG_PID_NS
7235 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7236 task, &pidns_operations);
7238 #ifdef CONFIG_CGROUPS
7239 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7240 task, &cgroupns_operations);
7243 perf_iterate_sb(perf_event_namespaces_output,
7252 struct perf_mmap_event {
7253 struct vm_area_struct *vma;
7255 const char *file_name;
7263 struct perf_event_header header;
7273 static int perf_event_mmap_match(struct perf_event *event,
7276 struct perf_mmap_event *mmap_event = data;
7277 struct vm_area_struct *vma = mmap_event->vma;
7278 int executable = vma->vm_flags & VM_EXEC;
7280 return (!executable && event->attr.mmap_data) ||
7281 (executable && (event->attr.mmap || event->attr.mmap2));
7284 static void perf_event_mmap_output(struct perf_event *event,
7287 struct perf_mmap_event *mmap_event = data;
7288 struct perf_output_handle handle;
7289 struct perf_sample_data sample;
7290 int size = mmap_event->event_id.header.size;
7291 u32 type = mmap_event->event_id.header.type;
7294 if (!perf_event_mmap_match(event, data))
7297 if (event->attr.mmap2) {
7298 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7299 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7300 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7301 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7302 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7303 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7304 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7307 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7308 ret = perf_output_begin(&handle, event,
7309 mmap_event->event_id.header.size);
7313 mmap_event->event_id.pid = perf_event_pid(event, current);
7314 mmap_event->event_id.tid = perf_event_tid(event, current);
7316 perf_output_put(&handle, mmap_event->event_id);
7318 if (event->attr.mmap2) {
7319 perf_output_put(&handle, mmap_event->maj);
7320 perf_output_put(&handle, mmap_event->min);
7321 perf_output_put(&handle, mmap_event->ino);
7322 perf_output_put(&handle, mmap_event->ino_generation);
7323 perf_output_put(&handle, mmap_event->prot);
7324 perf_output_put(&handle, mmap_event->flags);
7327 __output_copy(&handle, mmap_event->file_name,
7328 mmap_event->file_size);
7330 perf_event__output_id_sample(event, &handle, &sample);
7332 perf_output_end(&handle);
7334 mmap_event->event_id.header.size = size;
7335 mmap_event->event_id.header.type = type;
7338 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7340 struct vm_area_struct *vma = mmap_event->vma;
7341 struct file *file = vma->vm_file;
7342 int maj = 0, min = 0;
7343 u64 ino = 0, gen = 0;
7344 u32 prot = 0, flags = 0;
7350 if (vma->vm_flags & VM_READ)
7352 if (vma->vm_flags & VM_WRITE)
7354 if (vma->vm_flags & VM_EXEC)
7357 if (vma->vm_flags & VM_MAYSHARE)
7360 flags = MAP_PRIVATE;
7362 if (vma->vm_flags & VM_DENYWRITE)
7363 flags |= MAP_DENYWRITE;
7364 if (vma->vm_flags & VM_MAYEXEC)
7365 flags |= MAP_EXECUTABLE;
7366 if (vma->vm_flags & VM_LOCKED)
7367 flags |= MAP_LOCKED;
7368 if (vma->vm_flags & VM_HUGETLB)
7369 flags |= MAP_HUGETLB;
7372 struct inode *inode;
7375 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7381 * d_path() works from the end of the rb backwards, so we
7382 * need to add enough zero bytes after the string to handle
7383 * the 64bit alignment we do later.
7385 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7390 inode = file_inode(vma->vm_file);
7391 dev = inode->i_sb->s_dev;
7393 gen = inode->i_generation;
7399 if (vma->vm_ops && vma->vm_ops->name) {
7400 name = (char *) vma->vm_ops->name(vma);
7405 name = (char *)arch_vma_name(vma);
7409 if (vma->vm_start <= vma->vm_mm->start_brk &&
7410 vma->vm_end >= vma->vm_mm->brk) {
7414 if (vma->vm_start <= vma->vm_mm->start_stack &&
7415 vma->vm_end >= vma->vm_mm->start_stack) {
7425 strlcpy(tmp, name, sizeof(tmp));
7429 * Since our buffer works in 8 byte units we need to align our string
7430 * size to a multiple of 8. However, we must guarantee the tail end is
7431 * zero'd out to avoid leaking random bits to userspace.
7433 size = strlen(name)+1;
7434 while (!IS_ALIGNED(size, sizeof(u64)))
7435 name[size++] = '\0';
7437 mmap_event->file_name = name;
7438 mmap_event->file_size = size;
7439 mmap_event->maj = maj;
7440 mmap_event->min = min;
7441 mmap_event->ino = ino;
7442 mmap_event->ino_generation = gen;
7443 mmap_event->prot = prot;
7444 mmap_event->flags = flags;
7446 if (!(vma->vm_flags & VM_EXEC))
7447 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7449 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7451 perf_iterate_sb(perf_event_mmap_output,
7459 * Check whether inode and address range match filter criteria.
7461 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7462 struct file *file, unsigned long offset,
7465 /* d_inode(NULL) won't be equal to any mapped user-space file */
7466 if (!filter->path.dentry)
7469 if (d_inode(filter->path.dentry) != file_inode(file))
7472 if (filter->offset > offset + size)
7475 if (filter->offset + filter->size < offset)
7481 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
7482 struct vm_area_struct *vma,
7483 struct perf_addr_filter_range *fr)
7485 unsigned long vma_size = vma->vm_end - vma->vm_start;
7486 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7487 struct file *file = vma->vm_file;
7489 if (!perf_addr_filter_match(filter, file, off, vma_size))
7492 if (filter->offset < off) {
7493 fr->start = vma->vm_start;
7494 fr->size = min(vma_size, filter->size - (off - filter->offset));
7496 fr->start = vma->vm_start + filter->offset - off;
7497 fr->size = min(vma->vm_end - fr->start, filter->size);
7503 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7505 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7506 struct vm_area_struct *vma = data;
7507 struct perf_addr_filter *filter;
7508 unsigned int restart = 0, count = 0;
7509 unsigned long flags;
7511 if (!has_addr_filter(event))
7517 raw_spin_lock_irqsave(&ifh->lock, flags);
7518 list_for_each_entry(filter, &ifh->list, entry) {
7519 if (perf_addr_filter_vma_adjust(filter, vma,
7520 &event->addr_filter_ranges[count]))
7527 event->addr_filters_gen++;
7528 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7531 perf_event_stop(event, 1);
7535 * Adjust all task's events' filters to the new vma
7537 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7539 struct perf_event_context *ctx;
7543 * Data tracing isn't supported yet and as such there is no need
7544 * to keep track of anything that isn't related to executable code:
7546 if (!(vma->vm_flags & VM_EXEC))
7550 for_each_task_context_nr(ctxn) {
7551 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7555 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7560 void perf_event_mmap(struct vm_area_struct *vma)
7562 struct perf_mmap_event mmap_event;
7564 if (!atomic_read(&nr_mmap_events))
7567 mmap_event = (struct perf_mmap_event){
7573 .type = PERF_RECORD_MMAP,
7574 .misc = PERF_RECORD_MISC_USER,
7579 .start = vma->vm_start,
7580 .len = vma->vm_end - vma->vm_start,
7581 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7583 /* .maj (attr_mmap2 only) */
7584 /* .min (attr_mmap2 only) */
7585 /* .ino (attr_mmap2 only) */
7586 /* .ino_generation (attr_mmap2 only) */
7587 /* .prot (attr_mmap2 only) */
7588 /* .flags (attr_mmap2 only) */
7591 perf_addr_filters_adjust(vma);
7592 perf_event_mmap_event(&mmap_event);
7595 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7596 unsigned long size, u64 flags)
7598 struct perf_output_handle handle;
7599 struct perf_sample_data sample;
7600 struct perf_aux_event {
7601 struct perf_event_header header;
7607 .type = PERF_RECORD_AUX,
7609 .size = sizeof(rec),
7617 perf_event_header__init_id(&rec.header, &sample, event);
7618 ret = perf_output_begin(&handle, event, rec.header.size);
7623 perf_output_put(&handle, rec);
7624 perf_event__output_id_sample(event, &handle, &sample);
7626 perf_output_end(&handle);
7630 * Lost/dropped samples logging
7632 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7634 struct perf_output_handle handle;
7635 struct perf_sample_data sample;
7639 struct perf_event_header header;
7641 } lost_samples_event = {
7643 .type = PERF_RECORD_LOST_SAMPLES,
7645 .size = sizeof(lost_samples_event),
7650 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7652 ret = perf_output_begin(&handle, event,
7653 lost_samples_event.header.size);
7657 perf_output_put(&handle, lost_samples_event);
7658 perf_event__output_id_sample(event, &handle, &sample);
7659 perf_output_end(&handle);
7663 * context_switch tracking
7666 struct perf_switch_event {
7667 struct task_struct *task;
7668 struct task_struct *next_prev;
7671 struct perf_event_header header;
7677 static int perf_event_switch_match(struct perf_event *event)
7679 return event->attr.context_switch;
7682 static void perf_event_switch_output(struct perf_event *event, void *data)
7684 struct perf_switch_event *se = data;
7685 struct perf_output_handle handle;
7686 struct perf_sample_data sample;
7689 if (!perf_event_switch_match(event))
7692 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7693 if (event->ctx->task) {
7694 se->event_id.header.type = PERF_RECORD_SWITCH;
7695 se->event_id.header.size = sizeof(se->event_id.header);
7697 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7698 se->event_id.header.size = sizeof(se->event_id);
7699 se->event_id.next_prev_pid =
7700 perf_event_pid(event, se->next_prev);
7701 se->event_id.next_prev_tid =
7702 perf_event_tid(event, se->next_prev);
7705 perf_event_header__init_id(&se->event_id.header, &sample, event);
7707 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7711 if (event->ctx->task)
7712 perf_output_put(&handle, se->event_id.header);
7714 perf_output_put(&handle, se->event_id);
7716 perf_event__output_id_sample(event, &handle, &sample);
7718 perf_output_end(&handle);
7721 static void perf_event_switch(struct task_struct *task,
7722 struct task_struct *next_prev, bool sched_in)
7724 struct perf_switch_event switch_event;
7726 /* N.B. caller checks nr_switch_events != 0 */
7728 switch_event = (struct perf_switch_event){
7730 .next_prev = next_prev,
7734 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7737 /* .next_prev_pid */
7738 /* .next_prev_tid */
7742 if (!sched_in && task->state == TASK_RUNNING)
7743 switch_event.event_id.header.misc |=
7744 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
7746 perf_iterate_sb(perf_event_switch_output,
7752 * IRQ throttle logging
7755 static void perf_log_throttle(struct perf_event *event, int enable)
7757 struct perf_output_handle handle;
7758 struct perf_sample_data sample;
7762 struct perf_event_header header;
7766 } throttle_event = {
7768 .type = PERF_RECORD_THROTTLE,
7770 .size = sizeof(throttle_event),
7772 .time = perf_event_clock(event),
7773 .id = primary_event_id(event),
7774 .stream_id = event->id,
7778 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7780 perf_event_header__init_id(&throttle_event.header, &sample, event);
7782 ret = perf_output_begin(&handle, event,
7783 throttle_event.header.size);
7787 perf_output_put(&handle, throttle_event);
7788 perf_event__output_id_sample(event, &handle, &sample);
7789 perf_output_end(&handle);
7792 void perf_event_itrace_started(struct perf_event *event)
7794 event->attach_state |= PERF_ATTACH_ITRACE;
7797 static void perf_log_itrace_start(struct perf_event *event)
7799 struct perf_output_handle handle;
7800 struct perf_sample_data sample;
7801 struct perf_aux_event {
7802 struct perf_event_header header;
7809 event = event->parent;
7811 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7812 event->attach_state & PERF_ATTACH_ITRACE)
7815 rec.header.type = PERF_RECORD_ITRACE_START;
7816 rec.header.misc = 0;
7817 rec.header.size = sizeof(rec);
7818 rec.pid = perf_event_pid(event, current);
7819 rec.tid = perf_event_tid(event, current);
7821 perf_event_header__init_id(&rec.header, &sample, event);
7822 ret = perf_output_begin(&handle, event, rec.header.size);
7827 perf_output_put(&handle, rec);
7828 perf_event__output_id_sample(event, &handle, &sample);
7830 perf_output_end(&handle);
7834 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7836 struct hw_perf_event *hwc = &event->hw;
7840 seq = __this_cpu_read(perf_throttled_seq);
7841 if (seq != hwc->interrupts_seq) {
7842 hwc->interrupts_seq = seq;
7843 hwc->interrupts = 1;
7846 if (unlikely(throttle
7847 && hwc->interrupts >= max_samples_per_tick)) {
7848 __this_cpu_inc(perf_throttled_count);
7849 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7850 hwc->interrupts = MAX_INTERRUPTS;
7851 perf_log_throttle(event, 0);
7856 if (event->attr.freq) {
7857 u64 now = perf_clock();
7858 s64 delta = now - hwc->freq_time_stamp;
7860 hwc->freq_time_stamp = now;
7862 if (delta > 0 && delta < 2*TICK_NSEC)
7863 perf_adjust_period(event, delta, hwc->last_period, true);
7869 int perf_event_account_interrupt(struct perf_event *event)
7871 return __perf_event_account_interrupt(event, 1);
7875 * Generic event overflow handling, sampling.
7878 static int __perf_event_overflow(struct perf_event *event,
7879 int throttle, struct perf_sample_data *data,
7880 struct pt_regs *regs)
7882 int events = atomic_read(&event->event_limit);
7886 * Non-sampling counters might still use the PMI to fold short
7887 * hardware counters, ignore those.
7889 if (unlikely(!is_sampling_event(event)))
7892 ret = __perf_event_account_interrupt(event, throttle);
7895 * XXX event_limit might not quite work as expected on inherited
7899 event->pending_kill = POLL_IN;
7900 if (events && atomic_dec_and_test(&event->event_limit)) {
7902 event->pending_kill = POLL_HUP;
7904 perf_event_disable_inatomic(event);
7907 READ_ONCE(event->overflow_handler)(event, data, regs);
7909 if (*perf_event_fasync(event) && event->pending_kill) {
7910 event->pending_wakeup = 1;
7911 irq_work_queue(&event->pending);
7917 int perf_event_overflow(struct perf_event *event,
7918 struct perf_sample_data *data,
7919 struct pt_regs *regs)
7921 return __perf_event_overflow(event, 1, data, regs);
7925 * Generic software event infrastructure
7928 struct swevent_htable {
7929 struct swevent_hlist *swevent_hlist;
7930 struct mutex hlist_mutex;
7933 /* Recursion avoidance in each contexts */
7934 int recursion[PERF_NR_CONTEXTS];
7937 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7940 * We directly increment event->count and keep a second value in
7941 * event->hw.period_left to count intervals. This period event
7942 * is kept in the range [-sample_period, 0] so that we can use the
7946 u64 perf_swevent_set_period(struct perf_event *event)
7948 struct hw_perf_event *hwc = &event->hw;
7949 u64 period = hwc->last_period;
7953 hwc->last_period = hwc->sample_period;
7956 old = val = local64_read(&hwc->period_left);
7960 nr = div64_u64(period + val, period);
7961 offset = nr * period;
7963 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7969 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7970 struct perf_sample_data *data,
7971 struct pt_regs *regs)
7973 struct hw_perf_event *hwc = &event->hw;
7977 overflow = perf_swevent_set_period(event);
7979 if (hwc->interrupts == MAX_INTERRUPTS)
7982 for (; overflow; overflow--) {
7983 if (__perf_event_overflow(event, throttle,
7986 * We inhibit the overflow from happening when
7987 * hwc->interrupts == MAX_INTERRUPTS.
7995 static void perf_swevent_event(struct perf_event *event, u64 nr,
7996 struct perf_sample_data *data,
7997 struct pt_regs *regs)
7999 struct hw_perf_event *hwc = &event->hw;
8001 local64_add(nr, &event->count);
8006 if (!is_sampling_event(event))
8009 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
8011 return perf_swevent_overflow(event, 1, data, regs);
8013 data->period = event->hw.last_period;
8015 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
8016 return perf_swevent_overflow(event, 1, data, regs);
8018 if (local64_add_negative(nr, &hwc->period_left))
8021 perf_swevent_overflow(event, 0, data, regs);
8024 static int perf_exclude_event(struct perf_event *event,
8025 struct pt_regs *regs)
8027 if (event->hw.state & PERF_HES_STOPPED)
8031 if (event->attr.exclude_user && user_mode(regs))
8034 if (event->attr.exclude_kernel && !user_mode(regs))
8041 static int perf_swevent_match(struct perf_event *event,
8042 enum perf_type_id type,
8044 struct perf_sample_data *data,
8045 struct pt_regs *regs)
8047 if (event->attr.type != type)
8050 if (event->attr.config != event_id)
8053 if (perf_exclude_event(event, regs))
8059 static inline u64 swevent_hash(u64 type, u32 event_id)
8061 u64 val = event_id | (type << 32);
8063 return hash_64(val, SWEVENT_HLIST_BITS);
8066 static inline struct hlist_head *
8067 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
8069 u64 hash = swevent_hash(type, event_id);
8071 return &hlist->heads[hash];
8074 /* For the read side: events when they trigger */
8075 static inline struct hlist_head *
8076 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8078 struct swevent_hlist *hlist;
8080 hlist = rcu_dereference(swhash->swevent_hlist);
8084 return __find_swevent_head(hlist, type, event_id);
8087 /* For the event head insertion and removal in the hlist */
8088 static inline struct hlist_head *
8089 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8091 struct swevent_hlist *hlist;
8092 u32 event_id = event->attr.config;
8093 u64 type = event->attr.type;
8096 * Event scheduling is always serialized against hlist allocation
8097 * and release. Which makes the protected version suitable here.
8098 * The context lock guarantees that.
8100 hlist = rcu_dereference_protected(swhash->swevent_hlist,
8101 lockdep_is_held(&event->ctx->lock));
8105 return __find_swevent_head(hlist, type, event_id);
8108 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8110 struct perf_sample_data *data,
8111 struct pt_regs *regs)
8113 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8114 struct perf_event *event;
8115 struct hlist_head *head;
8118 head = find_swevent_head_rcu(swhash, type, event_id);
8122 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8123 if (perf_swevent_match(event, type, event_id, data, regs))
8124 perf_swevent_event(event, nr, data, regs);
8130 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8132 int perf_swevent_get_recursion_context(void)
8134 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8136 return get_recursion_context(swhash->recursion);
8138 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8140 void perf_swevent_put_recursion_context(int rctx)
8142 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8144 put_recursion_context(swhash->recursion, rctx);
8147 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8149 struct perf_sample_data data;
8151 if (WARN_ON_ONCE(!regs))
8154 perf_sample_data_init(&data, addr, 0);
8155 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8158 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8162 preempt_disable_notrace();
8163 rctx = perf_swevent_get_recursion_context();
8164 if (unlikely(rctx < 0))
8167 ___perf_sw_event(event_id, nr, regs, addr);
8169 perf_swevent_put_recursion_context(rctx);
8171 preempt_enable_notrace();
8174 static void perf_swevent_read(struct perf_event *event)
8178 static int perf_swevent_add(struct perf_event *event, int flags)
8180 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8181 struct hw_perf_event *hwc = &event->hw;
8182 struct hlist_head *head;
8184 if (is_sampling_event(event)) {
8185 hwc->last_period = hwc->sample_period;
8186 perf_swevent_set_period(event);
8189 hwc->state = !(flags & PERF_EF_START);
8191 head = find_swevent_head(swhash, event);
8192 if (WARN_ON_ONCE(!head))
8195 hlist_add_head_rcu(&event->hlist_entry, head);
8196 perf_event_update_userpage(event);
8201 static void perf_swevent_del(struct perf_event *event, int flags)
8203 hlist_del_rcu(&event->hlist_entry);
8206 static void perf_swevent_start(struct perf_event *event, int flags)
8208 event->hw.state = 0;
8211 static void perf_swevent_stop(struct perf_event *event, int flags)
8213 event->hw.state = PERF_HES_STOPPED;
8216 /* Deref the hlist from the update side */
8217 static inline struct swevent_hlist *
8218 swevent_hlist_deref(struct swevent_htable *swhash)
8220 return rcu_dereference_protected(swhash->swevent_hlist,
8221 lockdep_is_held(&swhash->hlist_mutex));
8224 static void swevent_hlist_release(struct swevent_htable *swhash)
8226 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
8231 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
8232 kfree_rcu(hlist, rcu_head);
8235 static void swevent_hlist_put_cpu(int cpu)
8237 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8239 mutex_lock(&swhash->hlist_mutex);
8241 if (!--swhash->hlist_refcount)
8242 swevent_hlist_release(swhash);
8244 mutex_unlock(&swhash->hlist_mutex);
8247 static void swevent_hlist_put(void)
8251 for_each_possible_cpu(cpu)
8252 swevent_hlist_put_cpu(cpu);
8255 static int swevent_hlist_get_cpu(int cpu)
8257 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8260 mutex_lock(&swhash->hlist_mutex);
8261 if (!swevent_hlist_deref(swhash) &&
8262 cpumask_test_cpu(cpu, perf_online_mask)) {
8263 struct swevent_hlist *hlist;
8265 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
8270 rcu_assign_pointer(swhash->swevent_hlist, hlist);
8272 swhash->hlist_refcount++;
8274 mutex_unlock(&swhash->hlist_mutex);
8279 static int swevent_hlist_get(void)
8281 int err, cpu, failed_cpu;
8283 mutex_lock(&pmus_lock);
8284 for_each_possible_cpu(cpu) {
8285 err = swevent_hlist_get_cpu(cpu);
8291 mutex_unlock(&pmus_lock);
8294 for_each_possible_cpu(cpu) {
8295 if (cpu == failed_cpu)
8297 swevent_hlist_put_cpu(cpu);
8299 mutex_unlock(&pmus_lock);
8303 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
8305 static void sw_perf_event_destroy(struct perf_event *event)
8307 u64 event_id = event->attr.config;
8309 WARN_ON(event->parent);
8311 static_key_slow_dec(&perf_swevent_enabled[event_id]);
8312 swevent_hlist_put();
8315 static int perf_swevent_init(struct perf_event *event)
8317 u64 event_id = event->attr.config;
8319 if (event->attr.type != PERF_TYPE_SOFTWARE)
8323 * no branch sampling for software events
8325 if (has_branch_stack(event))
8329 case PERF_COUNT_SW_CPU_CLOCK:
8330 case PERF_COUNT_SW_TASK_CLOCK:
8337 if (event_id >= PERF_COUNT_SW_MAX)
8340 if (!event->parent) {
8343 err = swevent_hlist_get();
8347 static_key_slow_inc(&perf_swevent_enabled[event_id]);
8348 event->destroy = sw_perf_event_destroy;
8354 static struct pmu perf_swevent = {
8355 .task_ctx_nr = perf_sw_context,
8357 .capabilities = PERF_PMU_CAP_NO_NMI,
8359 .event_init = perf_swevent_init,
8360 .add = perf_swevent_add,
8361 .del = perf_swevent_del,
8362 .start = perf_swevent_start,
8363 .stop = perf_swevent_stop,
8364 .read = perf_swevent_read,
8367 #ifdef CONFIG_EVENT_TRACING
8369 static int perf_tp_filter_match(struct perf_event *event,
8370 struct perf_sample_data *data)
8372 void *record = data->raw->frag.data;
8374 /* only top level events have filters set */
8376 event = event->parent;
8378 if (likely(!event->filter) || filter_match_preds(event->filter, record))
8383 static int perf_tp_event_match(struct perf_event *event,
8384 struct perf_sample_data *data,
8385 struct pt_regs *regs)
8387 if (event->hw.state & PERF_HES_STOPPED)
8390 * All tracepoints are from kernel-space.
8392 if (event->attr.exclude_kernel)
8395 if (!perf_tp_filter_match(event, data))
8401 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8402 struct trace_event_call *call, u64 count,
8403 struct pt_regs *regs, struct hlist_head *head,
8404 struct task_struct *task)
8406 if (bpf_prog_array_valid(call)) {
8407 *(struct pt_regs **)raw_data = regs;
8408 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
8409 perf_swevent_put_recursion_context(rctx);
8413 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8416 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8418 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8419 struct pt_regs *regs, struct hlist_head *head, int rctx,
8420 struct task_struct *task)
8422 struct perf_sample_data data;
8423 struct perf_event *event;
8425 struct perf_raw_record raw = {
8432 perf_sample_data_init(&data, 0, 0);
8435 perf_trace_buf_update(record, event_type);
8437 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8438 if (perf_tp_event_match(event, &data, regs))
8439 perf_swevent_event(event, count, &data, regs);
8443 * If we got specified a target task, also iterate its context and
8444 * deliver this event there too.
8446 if (task && task != current) {
8447 struct perf_event_context *ctx;
8448 struct trace_entry *entry = record;
8451 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8455 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8456 if (event->cpu != smp_processor_id())
8458 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8460 if (event->attr.config != entry->type)
8462 if (perf_tp_event_match(event, &data, regs))
8463 perf_swevent_event(event, count, &data, regs);
8469 perf_swevent_put_recursion_context(rctx);
8471 EXPORT_SYMBOL_GPL(perf_tp_event);
8473 static void tp_perf_event_destroy(struct perf_event *event)
8475 perf_trace_destroy(event);
8478 static int perf_tp_event_init(struct perf_event *event)
8482 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8486 * no branch sampling for tracepoint events
8488 if (has_branch_stack(event))
8491 err = perf_trace_init(event);
8495 event->destroy = tp_perf_event_destroy;
8500 static struct pmu perf_tracepoint = {
8501 .task_ctx_nr = perf_sw_context,
8503 .event_init = perf_tp_event_init,
8504 .add = perf_trace_add,
8505 .del = perf_trace_del,
8506 .start = perf_swevent_start,
8507 .stop = perf_swevent_stop,
8508 .read = perf_swevent_read,
8511 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
8513 * Flags in config, used by dynamic PMU kprobe and uprobe
8514 * The flags should match following PMU_FORMAT_ATTR().
8516 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
8517 * if not set, create kprobe/uprobe
8519 enum perf_probe_config {
8520 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
8523 PMU_FORMAT_ATTR(retprobe, "config:0");
8525 static struct attribute *probe_attrs[] = {
8526 &format_attr_retprobe.attr,
8530 static struct attribute_group probe_format_group = {
8532 .attrs = probe_attrs,
8535 static const struct attribute_group *probe_attr_groups[] = {
8536 &probe_format_group,
8541 #ifdef CONFIG_KPROBE_EVENTS
8542 static int perf_kprobe_event_init(struct perf_event *event);
8543 static struct pmu perf_kprobe = {
8544 .task_ctx_nr = perf_sw_context,
8545 .event_init = perf_kprobe_event_init,
8546 .add = perf_trace_add,
8547 .del = perf_trace_del,
8548 .start = perf_swevent_start,
8549 .stop = perf_swevent_stop,
8550 .read = perf_swevent_read,
8551 .attr_groups = probe_attr_groups,
8554 static int perf_kprobe_event_init(struct perf_event *event)
8559 if (event->attr.type != perf_kprobe.type)
8562 if (!capable(CAP_SYS_ADMIN))
8566 * no branch sampling for probe events
8568 if (has_branch_stack(event))
8571 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8572 err = perf_kprobe_init(event, is_retprobe);
8576 event->destroy = perf_kprobe_destroy;
8580 #endif /* CONFIG_KPROBE_EVENTS */
8582 #ifdef CONFIG_UPROBE_EVENTS
8583 static int perf_uprobe_event_init(struct perf_event *event);
8584 static struct pmu perf_uprobe = {
8585 .task_ctx_nr = perf_sw_context,
8586 .event_init = perf_uprobe_event_init,
8587 .add = perf_trace_add,
8588 .del = perf_trace_del,
8589 .start = perf_swevent_start,
8590 .stop = perf_swevent_stop,
8591 .read = perf_swevent_read,
8592 .attr_groups = probe_attr_groups,
8595 static int perf_uprobe_event_init(struct perf_event *event)
8600 if (event->attr.type != perf_uprobe.type)
8603 if (!capable(CAP_SYS_ADMIN))
8607 * no branch sampling for probe events
8609 if (has_branch_stack(event))
8612 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8613 err = perf_uprobe_init(event, is_retprobe);
8617 event->destroy = perf_uprobe_destroy;
8621 #endif /* CONFIG_UPROBE_EVENTS */
8623 static inline void perf_tp_register(void)
8625 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8626 #ifdef CONFIG_KPROBE_EVENTS
8627 perf_pmu_register(&perf_kprobe, "kprobe", -1);
8629 #ifdef CONFIG_UPROBE_EVENTS
8630 perf_pmu_register(&perf_uprobe, "uprobe", -1);
8634 static void perf_event_free_filter(struct perf_event *event)
8636 ftrace_profile_free_filter(event);
8639 #ifdef CONFIG_BPF_SYSCALL
8640 static void bpf_overflow_handler(struct perf_event *event,
8641 struct perf_sample_data *data,
8642 struct pt_regs *regs)
8644 struct bpf_perf_event_data_kern ctx = {
8650 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
8652 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8655 ret = BPF_PROG_RUN(event->prog, &ctx);
8658 __this_cpu_dec(bpf_prog_active);
8663 event->orig_overflow_handler(event, data, regs);
8666 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8668 struct bpf_prog *prog;
8670 if (event->overflow_handler_context)
8671 /* hw breakpoint or kernel counter */
8677 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8679 return PTR_ERR(prog);
8682 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8683 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8687 static void perf_event_free_bpf_handler(struct perf_event *event)
8689 struct bpf_prog *prog = event->prog;
8694 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8699 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8703 static void perf_event_free_bpf_handler(struct perf_event *event)
8709 * returns true if the event is a tracepoint, or a kprobe/upprobe created
8710 * with perf_event_open()
8712 static inline bool perf_event_is_tracing(struct perf_event *event)
8714 if (event->pmu == &perf_tracepoint)
8716 #ifdef CONFIG_KPROBE_EVENTS
8717 if (event->pmu == &perf_kprobe)
8720 #ifdef CONFIG_UPROBE_EVENTS
8721 if (event->pmu == &perf_uprobe)
8727 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8729 bool is_kprobe, is_tracepoint, is_syscall_tp;
8730 struct bpf_prog *prog;
8733 if (!perf_event_is_tracing(event))
8734 return perf_event_set_bpf_handler(event, prog_fd);
8736 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8737 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8738 is_syscall_tp = is_syscall_trace_event(event->tp_event);
8739 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
8740 /* bpf programs can only be attached to u/kprobe or tracepoint */
8743 prog = bpf_prog_get(prog_fd);
8745 return PTR_ERR(prog);
8747 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8748 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
8749 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8750 /* valid fd, but invalid bpf program type */
8755 /* Kprobe override only works for kprobes, not uprobes. */
8756 if (prog->kprobe_override &&
8757 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
8762 if (is_tracepoint || is_syscall_tp) {
8763 int off = trace_event_get_offsets(event->tp_event);
8765 if (prog->aux->max_ctx_offset > off) {
8771 ret = perf_event_attach_bpf_prog(event, prog);
8777 static void perf_event_free_bpf_prog(struct perf_event *event)
8779 if (!perf_event_is_tracing(event)) {
8780 perf_event_free_bpf_handler(event);
8783 perf_event_detach_bpf_prog(event);
8788 static inline void perf_tp_register(void)
8792 static void perf_event_free_filter(struct perf_event *event)
8796 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8801 static void perf_event_free_bpf_prog(struct perf_event *event)
8804 #endif /* CONFIG_EVENT_TRACING */
8806 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8807 void perf_bp_event(struct perf_event *bp, void *data)
8809 struct perf_sample_data sample;
8810 struct pt_regs *regs = data;
8812 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8814 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8815 perf_swevent_event(bp, 1, &sample, regs);
8820 * Allocate a new address filter
8822 static struct perf_addr_filter *
8823 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8825 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8826 struct perf_addr_filter *filter;
8828 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8832 INIT_LIST_HEAD(&filter->entry);
8833 list_add_tail(&filter->entry, filters);
8838 static void free_filters_list(struct list_head *filters)
8840 struct perf_addr_filter *filter, *iter;
8842 list_for_each_entry_safe(filter, iter, filters, entry) {
8843 path_put(&filter->path);
8844 list_del(&filter->entry);
8850 * Free existing address filters and optionally install new ones
8852 static void perf_addr_filters_splice(struct perf_event *event,
8853 struct list_head *head)
8855 unsigned long flags;
8858 if (!has_addr_filter(event))
8861 /* don't bother with children, they don't have their own filters */
8865 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8867 list_splice_init(&event->addr_filters.list, &list);
8869 list_splice(head, &event->addr_filters.list);
8871 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8873 free_filters_list(&list);
8877 * Scan through mm's vmas and see if one of them matches the
8878 * @filter; if so, adjust filter's address range.
8879 * Called with mm::mmap_sem down for reading.
8881 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
8882 struct mm_struct *mm,
8883 struct perf_addr_filter_range *fr)
8885 struct vm_area_struct *vma;
8887 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8891 if (perf_addr_filter_vma_adjust(filter, vma, fr))
8897 * Update event's address range filters based on the
8898 * task's existing mappings, if any.
8900 static void perf_event_addr_filters_apply(struct perf_event *event)
8902 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8903 struct task_struct *task = READ_ONCE(event->ctx->task);
8904 struct perf_addr_filter *filter;
8905 struct mm_struct *mm = NULL;
8906 unsigned int count = 0;
8907 unsigned long flags;
8910 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8911 * will stop on the parent's child_mutex that our caller is also holding
8913 if (task == TASK_TOMBSTONE)
8916 if (ifh->nr_file_filters) {
8917 mm = get_task_mm(task);
8921 down_read(&mm->mmap_sem);
8924 raw_spin_lock_irqsave(&ifh->lock, flags);
8925 list_for_each_entry(filter, &ifh->list, entry) {
8926 if (filter->path.dentry) {
8928 * Adjust base offset if the filter is associated to a
8929 * binary that needs to be mapped:
8931 event->addr_filter_ranges[count].start = 0;
8932 event->addr_filter_ranges[count].size = 0;
8934 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
8936 event->addr_filter_ranges[count].start = filter->offset;
8937 event->addr_filter_ranges[count].size = filter->size;
8943 event->addr_filters_gen++;
8944 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8946 if (ifh->nr_file_filters) {
8947 up_read(&mm->mmap_sem);
8953 perf_event_stop(event, 1);
8957 * Address range filtering: limiting the data to certain
8958 * instruction address ranges. Filters are ioctl()ed to us from
8959 * userspace as ascii strings.
8961 * Filter string format:
8964 * where ACTION is one of the
8965 * * "filter": limit the trace to this region
8966 * * "start": start tracing from this address
8967 * * "stop": stop tracing at this address/region;
8969 * * for kernel addresses: <start address>[/<size>]
8970 * * for object files: <start address>[/<size>]@</path/to/object/file>
8972 * if <size> is not specified or is zero, the range is treated as a single
8973 * address; not valid for ACTION=="filter".
8987 IF_STATE_ACTION = 0,
8992 static const match_table_t if_tokens = {
8993 { IF_ACT_FILTER, "filter" },
8994 { IF_ACT_START, "start" },
8995 { IF_ACT_STOP, "stop" },
8996 { IF_SRC_FILE, "%u/%u@%s" },
8997 { IF_SRC_KERNEL, "%u/%u" },
8998 { IF_SRC_FILEADDR, "%u@%s" },
8999 { IF_SRC_KERNELADDR, "%u" },
9000 { IF_ACT_NONE, NULL },
9004 * Address filter string parser
9007 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
9008 struct list_head *filters)
9010 struct perf_addr_filter *filter = NULL;
9011 char *start, *orig, *filename = NULL;
9012 substring_t args[MAX_OPT_ARGS];
9013 int state = IF_STATE_ACTION, token;
9014 unsigned int kernel = 0;
9017 orig = fstr = kstrdup(fstr, GFP_KERNEL);
9021 while ((start = strsep(&fstr, " ,\n")) != NULL) {
9022 static const enum perf_addr_filter_action_t actions[] = {
9023 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
9024 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
9025 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
9032 /* filter definition begins */
9033 if (state == IF_STATE_ACTION) {
9034 filter = perf_addr_filter_new(event, filters);
9039 token = match_token(start, if_tokens, args);
9044 if (state != IF_STATE_ACTION)
9047 filter->action = actions[token];
9048 state = IF_STATE_SOURCE;
9051 case IF_SRC_KERNELADDR:
9055 case IF_SRC_FILEADDR:
9057 if (state != IF_STATE_SOURCE)
9061 ret = kstrtoul(args[0].from, 0, &filter->offset);
9065 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
9067 ret = kstrtoul(args[1].from, 0, &filter->size);
9072 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9073 int fpos = token == IF_SRC_FILE ? 2 : 1;
9076 filename = match_strdup(&args[fpos]);
9083 state = IF_STATE_END;
9091 * Filter definition is fully parsed, validate and install it.
9092 * Make sure that it doesn't contradict itself or the event's
9095 if (state == IF_STATE_END) {
9097 if (kernel && event->attr.exclude_kernel)
9101 * ACTION "filter" must have a non-zero length region
9104 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9113 * For now, we only support file-based filters
9114 * in per-task events; doing so for CPU-wide
9115 * events requires additional context switching
9116 * trickery, since same object code will be
9117 * mapped at different virtual addresses in
9118 * different processes.
9121 if (!event->ctx->task)
9124 /* look up the path and grab its inode */
9125 ret = kern_path(filename, LOOKUP_FOLLOW,
9131 if (!filter->path.dentry ||
9132 !S_ISREG(d_inode(filter->path.dentry)
9136 event->addr_filters.nr_file_filters++;
9139 /* ready to consume more filters */
9142 state = IF_STATE_ACTION;
9148 if (state != IF_STATE_ACTION)
9158 free_filters_list(filters);
9165 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
9171 * Since this is called in perf_ioctl() path, we're already holding
9174 lockdep_assert_held(&event->ctx->mutex);
9176 if (WARN_ON_ONCE(event->parent))
9179 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
9181 goto fail_clear_files;
9183 ret = event->pmu->addr_filters_validate(&filters);
9185 goto fail_free_filters;
9187 /* remove existing filters, if any */
9188 perf_addr_filters_splice(event, &filters);
9190 /* install new filters */
9191 perf_event_for_each_child(event, perf_event_addr_filters_apply);
9196 free_filters_list(&filters);
9199 event->addr_filters.nr_file_filters = 0;
9204 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
9209 filter_str = strndup_user(arg, PAGE_SIZE);
9210 if (IS_ERR(filter_str))
9211 return PTR_ERR(filter_str);
9213 #ifdef CONFIG_EVENT_TRACING
9214 if (perf_event_is_tracing(event)) {
9215 struct perf_event_context *ctx = event->ctx;
9218 * Beware, here be dragons!!
9220 * the tracepoint muck will deadlock against ctx->mutex, but
9221 * the tracepoint stuff does not actually need it. So
9222 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
9223 * already have a reference on ctx.
9225 * This can result in event getting moved to a different ctx,
9226 * but that does not affect the tracepoint state.
9228 mutex_unlock(&ctx->mutex);
9229 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
9230 mutex_lock(&ctx->mutex);
9233 if (has_addr_filter(event))
9234 ret = perf_event_set_addr_filter(event, filter_str);
9241 * hrtimer based swevent callback
9244 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
9246 enum hrtimer_restart ret = HRTIMER_RESTART;
9247 struct perf_sample_data data;
9248 struct pt_regs *regs;
9249 struct perf_event *event;
9252 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
9254 if (event->state != PERF_EVENT_STATE_ACTIVE)
9255 return HRTIMER_NORESTART;
9257 event->pmu->read(event);
9259 perf_sample_data_init(&data, 0, event->hw.last_period);
9260 regs = get_irq_regs();
9262 if (regs && !perf_exclude_event(event, regs)) {
9263 if (!(event->attr.exclude_idle && is_idle_task(current)))
9264 if (__perf_event_overflow(event, 1, &data, regs))
9265 ret = HRTIMER_NORESTART;
9268 period = max_t(u64, 10000, event->hw.sample_period);
9269 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
9274 static void perf_swevent_start_hrtimer(struct perf_event *event)
9276 struct hw_perf_event *hwc = &event->hw;
9279 if (!is_sampling_event(event))
9282 period = local64_read(&hwc->period_left);
9287 local64_set(&hwc->period_left, 0);
9289 period = max_t(u64, 10000, hwc->sample_period);
9291 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
9292 HRTIMER_MODE_REL_PINNED);
9295 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
9297 struct hw_perf_event *hwc = &event->hw;
9299 if (is_sampling_event(event)) {
9300 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
9301 local64_set(&hwc->period_left, ktime_to_ns(remaining));
9303 hrtimer_cancel(&hwc->hrtimer);
9307 static void perf_swevent_init_hrtimer(struct perf_event *event)
9309 struct hw_perf_event *hwc = &event->hw;
9311 if (!is_sampling_event(event))
9314 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
9315 hwc->hrtimer.function = perf_swevent_hrtimer;
9318 * Since hrtimers have a fixed rate, we can do a static freq->period
9319 * mapping and avoid the whole period adjust feedback stuff.
9321 if (event->attr.freq) {
9322 long freq = event->attr.sample_freq;
9324 event->attr.sample_period = NSEC_PER_SEC / freq;
9325 hwc->sample_period = event->attr.sample_period;
9326 local64_set(&hwc->period_left, hwc->sample_period);
9327 hwc->last_period = hwc->sample_period;
9328 event->attr.freq = 0;
9333 * Software event: cpu wall time clock
9336 static void cpu_clock_event_update(struct perf_event *event)
9341 now = local_clock();
9342 prev = local64_xchg(&event->hw.prev_count, now);
9343 local64_add(now - prev, &event->count);
9346 static void cpu_clock_event_start(struct perf_event *event, int flags)
9348 local64_set(&event->hw.prev_count, local_clock());
9349 perf_swevent_start_hrtimer(event);
9352 static void cpu_clock_event_stop(struct perf_event *event, int flags)
9354 perf_swevent_cancel_hrtimer(event);
9355 cpu_clock_event_update(event);
9358 static int cpu_clock_event_add(struct perf_event *event, int flags)
9360 if (flags & PERF_EF_START)
9361 cpu_clock_event_start(event, flags);
9362 perf_event_update_userpage(event);
9367 static void cpu_clock_event_del(struct perf_event *event, int flags)
9369 cpu_clock_event_stop(event, flags);
9372 static void cpu_clock_event_read(struct perf_event *event)
9374 cpu_clock_event_update(event);
9377 static int cpu_clock_event_init(struct perf_event *event)
9379 if (event->attr.type != PERF_TYPE_SOFTWARE)
9382 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
9386 * no branch sampling for software events
9388 if (has_branch_stack(event))
9391 perf_swevent_init_hrtimer(event);
9396 static struct pmu perf_cpu_clock = {
9397 .task_ctx_nr = perf_sw_context,
9399 .capabilities = PERF_PMU_CAP_NO_NMI,
9401 .event_init = cpu_clock_event_init,
9402 .add = cpu_clock_event_add,
9403 .del = cpu_clock_event_del,
9404 .start = cpu_clock_event_start,
9405 .stop = cpu_clock_event_stop,
9406 .read = cpu_clock_event_read,
9410 * Software event: task time clock
9413 static void task_clock_event_update(struct perf_event *event, u64 now)
9418 prev = local64_xchg(&event->hw.prev_count, now);
9420 local64_add(delta, &event->count);
9423 static void task_clock_event_start(struct perf_event *event, int flags)
9425 local64_set(&event->hw.prev_count, event->ctx->time);
9426 perf_swevent_start_hrtimer(event);
9429 static void task_clock_event_stop(struct perf_event *event, int flags)
9431 perf_swevent_cancel_hrtimer(event);
9432 task_clock_event_update(event, event->ctx->time);
9435 static int task_clock_event_add(struct perf_event *event, int flags)
9437 if (flags & PERF_EF_START)
9438 task_clock_event_start(event, flags);
9439 perf_event_update_userpage(event);
9444 static void task_clock_event_del(struct perf_event *event, int flags)
9446 task_clock_event_stop(event, PERF_EF_UPDATE);
9449 static void task_clock_event_read(struct perf_event *event)
9451 u64 now = perf_clock();
9452 u64 delta = now - event->ctx->timestamp;
9453 u64 time = event->ctx->time + delta;
9455 task_clock_event_update(event, time);
9458 static int task_clock_event_init(struct perf_event *event)
9460 if (event->attr.type != PERF_TYPE_SOFTWARE)
9463 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
9467 * no branch sampling for software events
9469 if (has_branch_stack(event))
9472 perf_swevent_init_hrtimer(event);
9477 static struct pmu perf_task_clock = {
9478 .task_ctx_nr = perf_sw_context,
9480 .capabilities = PERF_PMU_CAP_NO_NMI,
9482 .event_init = task_clock_event_init,
9483 .add = task_clock_event_add,
9484 .del = task_clock_event_del,
9485 .start = task_clock_event_start,
9486 .stop = task_clock_event_stop,
9487 .read = task_clock_event_read,
9490 static void perf_pmu_nop_void(struct pmu *pmu)
9494 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
9498 static int perf_pmu_nop_int(struct pmu *pmu)
9503 static int perf_event_nop_int(struct perf_event *event, u64 value)
9508 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
9510 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
9512 __this_cpu_write(nop_txn_flags, flags);
9514 if (flags & ~PERF_PMU_TXN_ADD)
9517 perf_pmu_disable(pmu);
9520 static int perf_pmu_commit_txn(struct pmu *pmu)
9522 unsigned int flags = __this_cpu_read(nop_txn_flags);
9524 __this_cpu_write(nop_txn_flags, 0);
9526 if (flags & ~PERF_PMU_TXN_ADD)
9529 perf_pmu_enable(pmu);
9533 static void perf_pmu_cancel_txn(struct pmu *pmu)
9535 unsigned int flags = __this_cpu_read(nop_txn_flags);
9537 __this_cpu_write(nop_txn_flags, 0);
9539 if (flags & ~PERF_PMU_TXN_ADD)
9542 perf_pmu_enable(pmu);
9545 static int perf_event_idx_default(struct perf_event *event)
9551 * Ensures all contexts with the same task_ctx_nr have the same
9552 * pmu_cpu_context too.
9554 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
9561 list_for_each_entry(pmu, &pmus, entry) {
9562 if (pmu->task_ctx_nr == ctxn)
9563 return pmu->pmu_cpu_context;
9569 static void free_pmu_context(struct pmu *pmu)
9572 * Static contexts such as perf_sw_context have a global lifetime
9573 * and may be shared between different PMUs. Avoid freeing them
9574 * when a single PMU is going away.
9576 if (pmu->task_ctx_nr > perf_invalid_context)
9579 free_percpu(pmu->pmu_cpu_context);
9583 * Let userspace know that this PMU supports address range filtering:
9585 static ssize_t nr_addr_filters_show(struct device *dev,
9586 struct device_attribute *attr,
9589 struct pmu *pmu = dev_get_drvdata(dev);
9591 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
9593 DEVICE_ATTR_RO(nr_addr_filters);
9595 static struct idr pmu_idr;
9598 type_show(struct device *dev, struct device_attribute *attr, char *page)
9600 struct pmu *pmu = dev_get_drvdata(dev);
9602 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
9604 static DEVICE_ATTR_RO(type);
9607 perf_event_mux_interval_ms_show(struct device *dev,
9608 struct device_attribute *attr,
9611 struct pmu *pmu = dev_get_drvdata(dev);
9613 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9616 static DEFINE_MUTEX(mux_interval_mutex);
9619 perf_event_mux_interval_ms_store(struct device *dev,
9620 struct device_attribute *attr,
9621 const char *buf, size_t count)
9623 struct pmu *pmu = dev_get_drvdata(dev);
9624 int timer, cpu, ret;
9626 ret = kstrtoint(buf, 0, &timer);
9633 /* same value, noting to do */
9634 if (timer == pmu->hrtimer_interval_ms)
9637 mutex_lock(&mux_interval_mutex);
9638 pmu->hrtimer_interval_ms = timer;
9640 /* update all cpuctx for this PMU */
9642 for_each_online_cpu(cpu) {
9643 struct perf_cpu_context *cpuctx;
9644 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9645 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9647 cpu_function_call(cpu,
9648 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
9651 mutex_unlock(&mux_interval_mutex);
9655 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9657 static struct attribute *pmu_dev_attrs[] = {
9658 &dev_attr_type.attr,
9659 &dev_attr_perf_event_mux_interval_ms.attr,
9662 ATTRIBUTE_GROUPS(pmu_dev);
9664 static int pmu_bus_running;
9665 static struct bus_type pmu_bus = {
9666 .name = "event_source",
9667 .dev_groups = pmu_dev_groups,
9670 static void pmu_dev_release(struct device *dev)
9675 static int pmu_dev_alloc(struct pmu *pmu)
9679 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9683 pmu->dev->groups = pmu->attr_groups;
9684 device_initialize(pmu->dev);
9685 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9689 dev_set_drvdata(pmu->dev, pmu);
9690 pmu->dev->bus = &pmu_bus;
9691 pmu->dev->release = pmu_dev_release;
9692 ret = device_add(pmu->dev);
9696 /* For PMUs with address filters, throw in an extra attribute: */
9697 if (pmu->nr_addr_filters)
9698 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9707 device_del(pmu->dev);
9710 put_device(pmu->dev);
9714 static struct lock_class_key cpuctx_mutex;
9715 static struct lock_class_key cpuctx_lock;
9717 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9721 mutex_lock(&pmus_lock);
9723 pmu->pmu_disable_count = alloc_percpu(int);
9724 if (!pmu->pmu_disable_count)
9733 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9741 if (pmu_bus_running) {
9742 ret = pmu_dev_alloc(pmu);
9748 if (pmu->task_ctx_nr == perf_hw_context) {
9749 static int hw_context_taken = 0;
9752 * Other than systems with heterogeneous CPUs, it never makes
9753 * sense for two PMUs to share perf_hw_context. PMUs which are
9754 * uncore must use perf_invalid_context.
9756 if (WARN_ON_ONCE(hw_context_taken &&
9757 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9758 pmu->task_ctx_nr = perf_invalid_context;
9760 hw_context_taken = 1;
9763 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9764 if (pmu->pmu_cpu_context)
9765 goto got_cpu_context;
9768 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9769 if (!pmu->pmu_cpu_context)
9772 for_each_possible_cpu(cpu) {
9773 struct perf_cpu_context *cpuctx;
9775 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9776 __perf_event_init_context(&cpuctx->ctx);
9777 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9778 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9779 cpuctx->ctx.pmu = pmu;
9780 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9782 __perf_mux_hrtimer_init(cpuctx, cpu);
9786 if (!pmu->start_txn) {
9787 if (pmu->pmu_enable) {
9789 * If we have pmu_enable/pmu_disable calls, install
9790 * transaction stubs that use that to try and batch
9791 * hardware accesses.
9793 pmu->start_txn = perf_pmu_start_txn;
9794 pmu->commit_txn = perf_pmu_commit_txn;
9795 pmu->cancel_txn = perf_pmu_cancel_txn;
9797 pmu->start_txn = perf_pmu_nop_txn;
9798 pmu->commit_txn = perf_pmu_nop_int;
9799 pmu->cancel_txn = perf_pmu_nop_void;
9803 if (!pmu->pmu_enable) {
9804 pmu->pmu_enable = perf_pmu_nop_void;
9805 pmu->pmu_disable = perf_pmu_nop_void;
9808 if (!pmu->check_period)
9809 pmu->check_period = perf_event_nop_int;
9811 if (!pmu->event_idx)
9812 pmu->event_idx = perf_event_idx_default;
9814 list_add_rcu(&pmu->entry, &pmus);
9815 atomic_set(&pmu->exclusive_cnt, 0);
9818 mutex_unlock(&pmus_lock);
9823 device_del(pmu->dev);
9824 put_device(pmu->dev);
9827 if (pmu->type >= PERF_TYPE_MAX)
9828 idr_remove(&pmu_idr, pmu->type);
9831 free_percpu(pmu->pmu_disable_count);
9834 EXPORT_SYMBOL_GPL(perf_pmu_register);
9836 void perf_pmu_unregister(struct pmu *pmu)
9838 mutex_lock(&pmus_lock);
9839 list_del_rcu(&pmu->entry);
9842 * We dereference the pmu list under both SRCU and regular RCU, so
9843 * synchronize against both of those.
9845 synchronize_srcu(&pmus_srcu);
9848 free_percpu(pmu->pmu_disable_count);
9849 if (pmu->type >= PERF_TYPE_MAX)
9850 idr_remove(&pmu_idr, pmu->type);
9851 if (pmu_bus_running) {
9852 if (pmu->nr_addr_filters)
9853 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9854 device_del(pmu->dev);
9855 put_device(pmu->dev);
9857 free_pmu_context(pmu);
9858 mutex_unlock(&pmus_lock);
9860 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9862 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9864 struct perf_event_context *ctx = NULL;
9867 if (!try_module_get(pmu->module))
9871 * A number of pmu->event_init() methods iterate the sibling_list to,
9872 * for example, validate if the group fits on the PMU. Therefore,
9873 * if this is a sibling event, acquire the ctx->mutex to protect
9876 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
9878 * This ctx->mutex can nest when we're called through
9879 * inheritance. See the perf_event_ctx_lock_nested() comment.
9881 ctx = perf_event_ctx_lock_nested(event->group_leader,
9882 SINGLE_DEPTH_NESTING);
9887 ret = pmu->event_init(event);
9890 perf_event_ctx_unlock(event->group_leader, ctx);
9893 module_put(pmu->module);
9898 static struct pmu *perf_init_event(struct perf_event *event)
9904 idx = srcu_read_lock(&pmus_srcu);
9906 /* Try parent's PMU first: */
9907 if (event->parent && event->parent->pmu) {
9908 pmu = event->parent->pmu;
9909 ret = perf_try_init_event(pmu, event);
9915 pmu = idr_find(&pmu_idr, event->attr.type);
9918 ret = perf_try_init_event(pmu, event);
9924 list_for_each_entry_rcu(pmu, &pmus, entry) {
9925 ret = perf_try_init_event(pmu, event);
9929 if (ret != -ENOENT) {
9934 pmu = ERR_PTR(-ENOENT);
9936 srcu_read_unlock(&pmus_srcu, idx);
9941 static void attach_sb_event(struct perf_event *event)
9943 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9945 raw_spin_lock(&pel->lock);
9946 list_add_rcu(&event->sb_list, &pel->list);
9947 raw_spin_unlock(&pel->lock);
9951 * We keep a list of all !task (and therefore per-cpu) events
9952 * that need to receive side-band records.
9954 * This avoids having to scan all the various PMU per-cpu contexts
9957 static void account_pmu_sb_event(struct perf_event *event)
9959 if (is_sb_event(event))
9960 attach_sb_event(event);
9963 static void account_event_cpu(struct perf_event *event, int cpu)
9968 if (is_cgroup_event(event))
9969 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9972 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9973 static void account_freq_event_nohz(void)
9975 #ifdef CONFIG_NO_HZ_FULL
9976 /* Lock so we don't race with concurrent unaccount */
9977 spin_lock(&nr_freq_lock);
9978 if (atomic_inc_return(&nr_freq_events) == 1)
9979 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9980 spin_unlock(&nr_freq_lock);
9984 static void account_freq_event(void)
9986 if (tick_nohz_full_enabled())
9987 account_freq_event_nohz();
9989 atomic_inc(&nr_freq_events);
9993 static void account_event(struct perf_event *event)
10000 if (event->attach_state & PERF_ATTACH_TASK)
10002 if (event->attr.mmap || event->attr.mmap_data)
10003 atomic_inc(&nr_mmap_events);
10004 if (event->attr.comm)
10005 atomic_inc(&nr_comm_events);
10006 if (event->attr.namespaces)
10007 atomic_inc(&nr_namespaces_events);
10008 if (event->attr.task)
10009 atomic_inc(&nr_task_events);
10010 if (event->attr.freq)
10011 account_freq_event();
10012 if (event->attr.context_switch) {
10013 atomic_inc(&nr_switch_events);
10016 if (has_branch_stack(event))
10018 if (is_cgroup_event(event))
10023 * We need the mutex here because static_branch_enable()
10024 * must complete *before* the perf_sched_count increment
10027 if (atomic_inc_not_zero(&perf_sched_count))
10030 mutex_lock(&perf_sched_mutex);
10031 if (!atomic_read(&perf_sched_count)) {
10032 static_branch_enable(&perf_sched_events);
10034 * Guarantee that all CPUs observe they key change and
10035 * call the perf scheduling hooks before proceeding to
10036 * install events that need them.
10038 synchronize_sched();
10041 * Now that we have waited for the sync_sched(), allow further
10042 * increments to by-pass the mutex.
10044 atomic_inc(&perf_sched_count);
10045 mutex_unlock(&perf_sched_mutex);
10049 account_event_cpu(event, event->cpu);
10051 account_pmu_sb_event(event);
10055 * Allocate and initialize an event structure
10057 static struct perf_event *
10058 perf_event_alloc(struct perf_event_attr *attr, int cpu,
10059 struct task_struct *task,
10060 struct perf_event *group_leader,
10061 struct perf_event *parent_event,
10062 perf_overflow_handler_t overflow_handler,
10063 void *context, int cgroup_fd)
10066 struct perf_event *event;
10067 struct hw_perf_event *hwc;
10068 long err = -EINVAL;
10070 if ((unsigned)cpu >= nr_cpu_ids) {
10071 if (!task || cpu != -1)
10072 return ERR_PTR(-EINVAL);
10075 event = kzalloc(sizeof(*event), GFP_KERNEL);
10077 return ERR_PTR(-ENOMEM);
10080 * Single events are their own group leaders, with an
10081 * empty sibling list:
10084 group_leader = event;
10086 mutex_init(&event->child_mutex);
10087 INIT_LIST_HEAD(&event->child_list);
10089 INIT_LIST_HEAD(&event->event_entry);
10090 INIT_LIST_HEAD(&event->sibling_list);
10091 INIT_LIST_HEAD(&event->active_list);
10092 init_event_group(event);
10093 INIT_LIST_HEAD(&event->rb_entry);
10094 INIT_LIST_HEAD(&event->active_entry);
10095 INIT_LIST_HEAD(&event->addr_filters.list);
10096 INIT_HLIST_NODE(&event->hlist_entry);
10099 init_waitqueue_head(&event->waitq);
10100 event->pending_disable = -1;
10101 init_irq_work(&event->pending, perf_pending_event);
10103 mutex_init(&event->mmap_mutex);
10104 raw_spin_lock_init(&event->addr_filters.lock);
10106 atomic_long_set(&event->refcount, 1);
10108 event->attr = *attr;
10109 event->group_leader = group_leader;
10113 event->parent = parent_event;
10115 event->ns = get_pid_ns(task_active_pid_ns(current));
10116 event->id = atomic64_inc_return(&perf_event_id);
10118 event->state = PERF_EVENT_STATE_INACTIVE;
10121 event->attach_state = PERF_ATTACH_TASK;
10123 * XXX pmu::event_init needs to know what task to account to
10124 * and we cannot use the ctx information because we need the
10125 * pmu before we get a ctx.
10127 get_task_struct(task);
10128 event->hw.target = task;
10131 event->clock = &local_clock;
10133 event->clock = parent_event->clock;
10135 if (!overflow_handler && parent_event) {
10136 overflow_handler = parent_event->overflow_handler;
10137 context = parent_event->overflow_handler_context;
10138 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
10139 if (overflow_handler == bpf_overflow_handler) {
10140 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
10142 if (IS_ERR(prog)) {
10143 err = PTR_ERR(prog);
10146 event->prog = prog;
10147 event->orig_overflow_handler =
10148 parent_event->orig_overflow_handler;
10153 if (overflow_handler) {
10154 event->overflow_handler = overflow_handler;
10155 event->overflow_handler_context = context;
10156 } else if (is_write_backward(event)){
10157 event->overflow_handler = perf_event_output_backward;
10158 event->overflow_handler_context = NULL;
10160 event->overflow_handler = perf_event_output_forward;
10161 event->overflow_handler_context = NULL;
10164 perf_event__state_init(event);
10169 hwc->sample_period = attr->sample_period;
10170 if (attr->freq && attr->sample_freq)
10171 hwc->sample_period = 1;
10172 hwc->last_period = hwc->sample_period;
10174 local64_set(&hwc->period_left, hwc->sample_period);
10177 * We currently do not support PERF_SAMPLE_READ on inherited events.
10178 * See perf_output_read().
10180 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
10183 if (!has_branch_stack(event))
10184 event->attr.branch_sample_type = 0;
10186 if (cgroup_fd != -1) {
10187 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
10192 pmu = perf_init_event(event);
10194 err = PTR_ERR(pmu);
10198 err = exclusive_event_init(event);
10202 if (has_addr_filter(event)) {
10203 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
10204 sizeof(struct perf_addr_filter_range),
10206 if (!event->addr_filter_ranges) {
10212 * Clone the parent's vma offsets: they are valid until exec()
10213 * even if the mm is not shared with the parent.
10215 if (event->parent) {
10216 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10218 raw_spin_lock_irq(&ifh->lock);
10219 memcpy(event->addr_filter_ranges,
10220 event->parent->addr_filter_ranges,
10221 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
10222 raw_spin_unlock_irq(&ifh->lock);
10225 /* force hw sync on the address filters */
10226 event->addr_filters_gen = 1;
10229 if (!event->parent) {
10230 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
10231 err = get_callchain_buffers(attr->sample_max_stack);
10233 goto err_addr_filters;
10237 /* symmetric to unaccount_event() in _free_event() */
10238 account_event(event);
10243 kfree(event->addr_filter_ranges);
10246 exclusive_event_destroy(event);
10249 if (event->destroy)
10250 event->destroy(event);
10251 module_put(pmu->module);
10253 if (is_cgroup_event(event))
10254 perf_detach_cgroup(event);
10256 put_pid_ns(event->ns);
10257 if (event->hw.target)
10258 put_task_struct(event->hw.target);
10261 return ERR_PTR(err);
10264 static int perf_copy_attr(struct perf_event_attr __user *uattr,
10265 struct perf_event_attr *attr)
10270 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
10274 * zero the full structure, so that a short copy will be nice.
10276 memset(attr, 0, sizeof(*attr));
10278 ret = get_user(size, &uattr->size);
10282 if (size > PAGE_SIZE) /* silly large */
10285 if (!size) /* abi compat */
10286 size = PERF_ATTR_SIZE_VER0;
10288 if (size < PERF_ATTR_SIZE_VER0)
10292 * If we're handed a bigger struct than we know of,
10293 * ensure all the unknown bits are 0 - i.e. new
10294 * user-space does not rely on any kernel feature
10295 * extensions we dont know about yet.
10297 if (size > sizeof(*attr)) {
10298 unsigned char __user *addr;
10299 unsigned char __user *end;
10302 addr = (void __user *)uattr + sizeof(*attr);
10303 end = (void __user *)uattr + size;
10305 for (; addr < end; addr++) {
10306 ret = get_user(val, addr);
10312 size = sizeof(*attr);
10315 ret = copy_from_user(attr, uattr, size);
10321 if (attr->__reserved_1)
10324 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
10327 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
10330 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
10331 u64 mask = attr->branch_sample_type;
10333 /* only using defined bits */
10334 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
10337 /* at least one branch bit must be set */
10338 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
10341 /* propagate priv level, when not set for branch */
10342 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
10344 /* exclude_kernel checked on syscall entry */
10345 if (!attr->exclude_kernel)
10346 mask |= PERF_SAMPLE_BRANCH_KERNEL;
10348 if (!attr->exclude_user)
10349 mask |= PERF_SAMPLE_BRANCH_USER;
10351 if (!attr->exclude_hv)
10352 mask |= PERF_SAMPLE_BRANCH_HV;
10354 * adjust user setting (for HW filter setup)
10356 attr->branch_sample_type = mask;
10358 /* privileged levels capture (kernel, hv): check permissions */
10359 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
10360 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10364 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
10365 ret = perf_reg_validate(attr->sample_regs_user);
10370 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
10371 if (!arch_perf_have_user_stack_dump())
10375 * We have __u32 type for the size, but so far
10376 * we can only use __u16 as maximum due to the
10377 * __u16 sample size limit.
10379 if (attr->sample_stack_user >= USHRT_MAX)
10381 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
10385 if (!attr->sample_max_stack)
10386 attr->sample_max_stack = sysctl_perf_event_max_stack;
10388 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
10389 ret = perf_reg_validate(attr->sample_regs_intr);
10394 put_user(sizeof(*attr), &uattr->size);
10400 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
10402 struct ring_buffer *rb = NULL;
10408 /* don't allow circular references */
10409 if (event == output_event)
10413 * Don't allow cross-cpu buffers
10415 if (output_event->cpu != event->cpu)
10419 * If its not a per-cpu rb, it must be the same task.
10421 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
10425 * Mixing clocks in the same buffer is trouble you don't need.
10427 if (output_event->clock != event->clock)
10431 * Either writing ring buffer from beginning or from end.
10432 * Mixing is not allowed.
10434 if (is_write_backward(output_event) != is_write_backward(event))
10438 * If both events generate aux data, they must be on the same PMU
10440 if (has_aux(event) && has_aux(output_event) &&
10441 event->pmu != output_event->pmu)
10445 mutex_lock(&event->mmap_mutex);
10446 /* Can't redirect output if we've got an active mmap() */
10447 if (atomic_read(&event->mmap_count))
10450 if (output_event) {
10451 /* get the rb we want to redirect to */
10452 rb = ring_buffer_get(output_event);
10457 ring_buffer_attach(event, rb);
10461 mutex_unlock(&event->mmap_mutex);
10467 static void mutex_lock_double(struct mutex *a, struct mutex *b)
10473 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
10476 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
10478 bool nmi_safe = false;
10481 case CLOCK_MONOTONIC:
10482 event->clock = &ktime_get_mono_fast_ns;
10486 case CLOCK_MONOTONIC_RAW:
10487 event->clock = &ktime_get_raw_fast_ns;
10491 case CLOCK_REALTIME:
10492 event->clock = &ktime_get_real_ns;
10495 case CLOCK_BOOTTIME:
10496 event->clock = &ktime_get_boot_ns;
10500 event->clock = &ktime_get_tai_ns;
10507 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
10514 * Variation on perf_event_ctx_lock_nested(), except we take two context
10517 static struct perf_event_context *
10518 __perf_event_ctx_lock_double(struct perf_event *group_leader,
10519 struct perf_event_context *ctx)
10521 struct perf_event_context *gctx;
10525 gctx = READ_ONCE(group_leader->ctx);
10526 if (!atomic_inc_not_zero(&gctx->refcount)) {
10532 mutex_lock_double(&gctx->mutex, &ctx->mutex);
10534 if (group_leader->ctx != gctx) {
10535 mutex_unlock(&ctx->mutex);
10536 mutex_unlock(&gctx->mutex);
10545 * sys_perf_event_open - open a performance event, associate it to a task/cpu
10547 * @attr_uptr: event_id type attributes for monitoring/sampling
10550 * @group_fd: group leader event fd
10552 SYSCALL_DEFINE5(perf_event_open,
10553 struct perf_event_attr __user *, attr_uptr,
10554 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
10556 struct perf_event *group_leader = NULL, *output_event = NULL;
10557 struct perf_event *event, *sibling;
10558 struct perf_event_attr attr;
10559 struct perf_event_context *ctx, *uninitialized_var(gctx);
10560 struct file *event_file = NULL;
10561 struct fd group = {NULL, 0};
10562 struct task_struct *task = NULL;
10565 int move_group = 0;
10567 int f_flags = O_RDWR;
10568 int cgroup_fd = -1;
10570 /* for future expandability... */
10571 if (flags & ~PERF_FLAG_ALL)
10574 err = perf_copy_attr(attr_uptr, &attr);
10578 if (!attr.exclude_kernel) {
10579 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10583 if (attr.namespaces) {
10584 if (!capable(CAP_SYS_ADMIN))
10589 if (attr.sample_freq > sysctl_perf_event_sample_rate)
10592 if (attr.sample_period & (1ULL << 63))
10596 /* Only privileged users can get physical addresses */
10597 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
10598 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10602 * In cgroup mode, the pid argument is used to pass the fd
10603 * opened to the cgroup directory in cgroupfs. The cpu argument
10604 * designates the cpu on which to monitor threads from that
10607 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
10610 if (flags & PERF_FLAG_FD_CLOEXEC)
10611 f_flags |= O_CLOEXEC;
10613 event_fd = get_unused_fd_flags(f_flags);
10617 if (group_fd != -1) {
10618 err = perf_fget_light(group_fd, &group);
10621 group_leader = group.file->private_data;
10622 if (flags & PERF_FLAG_FD_OUTPUT)
10623 output_event = group_leader;
10624 if (flags & PERF_FLAG_FD_NO_GROUP)
10625 group_leader = NULL;
10628 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
10629 task = find_lively_task_by_vpid(pid);
10630 if (IS_ERR(task)) {
10631 err = PTR_ERR(task);
10636 if (task && group_leader &&
10637 group_leader->attr.inherit != attr.inherit) {
10643 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
10648 * Reuse ptrace permission checks for now.
10650 * We must hold cred_guard_mutex across this and any potential
10651 * perf_install_in_context() call for this new event to
10652 * serialize against exec() altering our credentials (and the
10653 * perf_event_exit_task() that could imply).
10656 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
10660 if (flags & PERF_FLAG_PID_CGROUP)
10663 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10664 NULL, NULL, cgroup_fd);
10665 if (IS_ERR(event)) {
10666 err = PTR_ERR(event);
10670 if (is_sampling_event(event)) {
10671 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
10678 * Special case software events and allow them to be part of
10679 * any hardware group.
10683 if (attr.use_clockid) {
10684 err = perf_event_set_clock(event, attr.clockid);
10689 if (pmu->task_ctx_nr == perf_sw_context)
10690 event->event_caps |= PERF_EV_CAP_SOFTWARE;
10692 if (group_leader) {
10693 if (is_software_event(event) &&
10694 !in_software_context(group_leader)) {
10696 * If the event is a sw event, but the group_leader
10697 * is on hw context.
10699 * Allow the addition of software events to hw
10700 * groups, this is safe because software events
10701 * never fail to schedule.
10703 pmu = group_leader->ctx->pmu;
10704 } else if (!is_software_event(event) &&
10705 is_software_event(group_leader) &&
10706 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10708 * In case the group is a pure software group, and we
10709 * try to add a hardware event, move the whole group to
10710 * the hardware context.
10717 * Get the target context (task or percpu):
10719 ctx = find_get_context(pmu, task, event);
10721 err = PTR_ERR(ctx);
10726 * Look up the group leader (we will attach this event to it):
10728 if (group_leader) {
10732 * Do not allow a recursive hierarchy (this new sibling
10733 * becoming part of another group-sibling):
10735 if (group_leader->group_leader != group_leader)
10738 /* All events in a group should have the same clock */
10739 if (group_leader->clock != event->clock)
10743 * Make sure we're both events for the same CPU;
10744 * grouping events for different CPUs is broken; since
10745 * you can never concurrently schedule them anyhow.
10747 if (group_leader->cpu != event->cpu)
10751 * Make sure we're both on the same task, or both
10754 if (group_leader->ctx->task != ctx->task)
10758 * Do not allow to attach to a group in a different task
10759 * or CPU context. If we're moving SW events, we'll fix
10760 * this up later, so allow that.
10762 if (!move_group && group_leader->ctx != ctx)
10766 * Only a group leader can be exclusive or pinned
10768 if (attr.exclusive || attr.pinned)
10772 if (output_event) {
10773 err = perf_event_set_output(event, output_event);
10778 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10780 if (IS_ERR(event_file)) {
10781 err = PTR_ERR(event_file);
10787 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10789 if (gctx->task == TASK_TOMBSTONE) {
10795 * Check if we raced against another sys_perf_event_open() call
10796 * moving the software group underneath us.
10798 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10800 * If someone moved the group out from under us, check
10801 * if this new event wound up on the same ctx, if so
10802 * its the regular !move_group case, otherwise fail.
10808 perf_event_ctx_unlock(group_leader, gctx);
10814 * Failure to create exclusive events returns -EBUSY.
10817 if (!exclusive_event_installable(group_leader, ctx))
10820 for_each_sibling_event(sibling, group_leader) {
10821 if (!exclusive_event_installable(sibling, ctx))
10825 mutex_lock(&ctx->mutex);
10828 if (ctx->task == TASK_TOMBSTONE) {
10833 if (!perf_event_validate_size(event)) {
10840 * Check if the @cpu we're creating an event for is online.
10842 * We use the perf_cpu_context::ctx::mutex to serialize against
10843 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10845 struct perf_cpu_context *cpuctx =
10846 container_of(ctx, struct perf_cpu_context, ctx);
10848 if (!cpuctx->online) {
10856 * Must be under the same ctx::mutex as perf_install_in_context(),
10857 * because we need to serialize with concurrent event creation.
10859 if (!exclusive_event_installable(event, ctx)) {
10864 WARN_ON_ONCE(ctx->parent_ctx);
10867 * This is the point on no return; we cannot fail hereafter. This is
10868 * where we start modifying current state.
10873 * See perf_event_ctx_lock() for comments on the details
10874 * of swizzling perf_event::ctx.
10876 perf_remove_from_context(group_leader, 0);
10879 for_each_sibling_event(sibling, group_leader) {
10880 perf_remove_from_context(sibling, 0);
10885 * Wait for everybody to stop referencing the events through
10886 * the old lists, before installing it on new lists.
10891 * Install the group siblings before the group leader.
10893 * Because a group leader will try and install the entire group
10894 * (through the sibling list, which is still in-tact), we can
10895 * end up with siblings installed in the wrong context.
10897 * By installing siblings first we NO-OP because they're not
10898 * reachable through the group lists.
10900 for_each_sibling_event(sibling, group_leader) {
10901 perf_event__state_init(sibling);
10902 perf_install_in_context(ctx, sibling, sibling->cpu);
10907 * Removing from the context ends up with disabled
10908 * event. What we want here is event in the initial
10909 * startup state, ready to be add into new context.
10911 perf_event__state_init(group_leader);
10912 perf_install_in_context(ctx, group_leader, group_leader->cpu);
10917 * Precalculate sample_data sizes; do while holding ctx::mutex such
10918 * that we're serialized against further additions and before
10919 * perf_install_in_context() which is the point the event is active and
10920 * can use these values.
10922 perf_event__header_size(event);
10923 perf_event__id_header_size(event);
10925 event->owner = current;
10927 perf_install_in_context(ctx, event, event->cpu);
10928 perf_unpin_context(ctx);
10931 perf_event_ctx_unlock(group_leader, gctx);
10932 mutex_unlock(&ctx->mutex);
10935 mutex_unlock(&task->signal->cred_guard_mutex);
10936 put_task_struct(task);
10939 mutex_lock(¤t->perf_event_mutex);
10940 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10941 mutex_unlock(¤t->perf_event_mutex);
10944 * Drop the reference on the group_event after placing the
10945 * new event on the sibling_list. This ensures destruction
10946 * of the group leader will find the pointer to itself in
10947 * perf_group_detach().
10950 fd_install(event_fd, event_file);
10955 perf_event_ctx_unlock(group_leader, gctx);
10956 mutex_unlock(&ctx->mutex);
10960 perf_unpin_context(ctx);
10964 * If event_file is set, the fput() above will have called ->release()
10965 * and that will take care of freeing the event.
10971 mutex_unlock(&task->signal->cred_guard_mutex);
10974 put_task_struct(task);
10978 put_unused_fd(event_fd);
10983 * perf_event_create_kernel_counter
10985 * @attr: attributes of the counter to create
10986 * @cpu: cpu in which the counter is bound
10987 * @task: task to profile (NULL for percpu)
10989 struct perf_event *
10990 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10991 struct task_struct *task,
10992 perf_overflow_handler_t overflow_handler,
10995 struct perf_event_context *ctx;
10996 struct perf_event *event;
11000 * Get the target context (task or percpu):
11003 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
11004 overflow_handler, context, -1);
11005 if (IS_ERR(event)) {
11006 err = PTR_ERR(event);
11010 /* Mark owner so we could distinguish it from user events. */
11011 event->owner = TASK_TOMBSTONE;
11013 ctx = find_get_context(event->pmu, task, event);
11015 err = PTR_ERR(ctx);
11019 WARN_ON_ONCE(ctx->parent_ctx);
11020 mutex_lock(&ctx->mutex);
11021 if (ctx->task == TASK_TOMBSTONE) {
11028 * Check if the @cpu we're creating an event for is online.
11030 * We use the perf_cpu_context::ctx::mutex to serialize against
11031 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11033 struct perf_cpu_context *cpuctx =
11034 container_of(ctx, struct perf_cpu_context, ctx);
11035 if (!cpuctx->online) {
11041 if (!exclusive_event_installable(event, ctx)) {
11046 perf_install_in_context(ctx, event, event->cpu);
11047 perf_unpin_context(ctx);
11048 mutex_unlock(&ctx->mutex);
11053 mutex_unlock(&ctx->mutex);
11054 perf_unpin_context(ctx);
11059 return ERR_PTR(err);
11061 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
11063 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
11065 struct perf_event_context *src_ctx;
11066 struct perf_event_context *dst_ctx;
11067 struct perf_event *event, *tmp;
11070 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
11071 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
11074 * See perf_event_ctx_lock() for comments on the details
11075 * of swizzling perf_event::ctx.
11077 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
11078 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
11080 perf_remove_from_context(event, 0);
11081 unaccount_event_cpu(event, src_cpu);
11083 list_add(&event->migrate_entry, &events);
11087 * Wait for the events to quiesce before re-instating them.
11092 * Re-instate events in 2 passes.
11094 * Skip over group leaders and only install siblings on this first
11095 * pass, siblings will not get enabled without a leader, however a
11096 * leader will enable its siblings, even if those are still on the old
11099 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11100 if (event->group_leader == event)
11103 list_del(&event->migrate_entry);
11104 if (event->state >= PERF_EVENT_STATE_OFF)
11105 event->state = PERF_EVENT_STATE_INACTIVE;
11106 account_event_cpu(event, dst_cpu);
11107 perf_install_in_context(dst_ctx, event, dst_cpu);
11112 * Once all the siblings are setup properly, install the group leaders
11115 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11116 list_del(&event->migrate_entry);
11117 if (event->state >= PERF_EVENT_STATE_OFF)
11118 event->state = PERF_EVENT_STATE_INACTIVE;
11119 account_event_cpu(event, dst_cpu);
11120 perf_install_in_context(dst_ctx, event, dst_cpu);
11123 mutex_unlock(&dst_ctx->mutex);
11124 mutex_unlock(&src_ctx->mutex);
11126 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
11128 static void sync_child_event(struct perf_event *child_event,
11129 struct task_struct *child)
11131 struct perf_event *parent_event = child_event->parent;
11134 if (child_event->attr.inherit_stat)
11135 perf_event_read_event(child_event, child);
11137 child_val = perf_event_count(child_event);
11140 * Add back the child's count to the parent's count:
11142 atomic64_add(child_val, &parent_event->child_count);
11143 atomic64_add(child_event->total_time_enabled,
11144 &parent_event->child_total_time_enabled);
11145 atomic64_add(child_event->total_time_running,
11146 &parent_event->child_total_time_running);
11150 perf_event_exit_event(struct perf_event *child_event,
11151 struct perf_event_context *child_ctx,
11152 struct task_struct *child)
11154 struct perf_event *parent_event = child_event->parent;
11157 * Do not destroy the 'original' grouping; because of the context
11158 * switch optimization the original events could've ended up in a
11159 * random child task.
11161 * If we were to destroy the original group, all group related
11162 * operations would cease to function properly after this random
11165 * Do destroy all inherited groups, we don't care about those
11166 * and being thorough is better.
11168 raw_spin_lock_irq(&child_ctx->lock);
11169 WARN_ON_ONCE(child_ctx->is_active);
11172 perf_group_detach(child_event);
11173 list_del_event(child_event, child_ctx);
11174 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
11175 raw_spin_unlock_irq(&child_ctx->lock);
11178 * Parent events are governed by their filedesc, retain them.
11180 if (!parent_event) {
11181 perf_event_wakeup(child_event);
11185 * Child events can be cleaned up.
11188 sync_child_event(child_event, child);
11191 * Remove this event from the parent's list
11193 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
11194 mutex_lock(&parent_event->child_mutex);
11195 list_del_init(&child_event->child_list);
11196 mutex_unlock(&parent_event->child_mutex);
11199 * Kick perf_poll() for is_event_hup().
11201 perf_event_wakeup(parent_event);
11202 free_event(child_event);
11203 put_event(parent_event);
11206 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
11208 struct perf_event_context *child_ctx, *clone_ctx = NULL;
11209 struct perf_event *child_event, *next;
11211 WARN_ON_ONCE(child != current);
11213 child_ctx = perf_pin_task_context(child, ctxn);
11218 * In order to reduce the amount of tricky in ctx tear-down, we hold
11219 * ctx::mutex over the entire thing. This serializes against almost
11220 * everything that wants to access the ctx.
11222 * The exception is sys_perf_event_open() /
11223 * perf_event_create_kernel_count() which does find_get_context()
11224 * without ctx::mutex (it cannot because of the move_group double mutex
11225 * lock thing). See the comments in perf_install_in_context().
11227 mutex_lock(&child_ctx->mutex);
11230 * In a single ctx::lock section, de-schedule the events and detach the
11231 * context from the task such that we cannot ever get it scheduled back
11234 raw_spin_lock_irq(&child_ctx->lock);
11235 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
11238 * Now that the context is inactive, destroy the task <-> ctx relation
11239 * and mark the context dead.
11241 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
11242 put_ctx(child_ctx); /* cannot be last */
11243 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
11244 put_task_struct(current); /* cannot be last */
11246 clone_ctx = unclone_ctx(child_ctx);
11247 raw_spin_unlock_irq(&child_ctx->lock);
11250 put_ctx(clone_ctx);
11253 * Report the task dead after unscheduling the events so that we
11254 * won't get any samples after PERF_RECORD_EXIT. We can however still
11255 * get a few PERF_RECORD_READ events.
11257 perf_event_task(child, child_ctx, 0);
11259 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
11260 perf_event_exit_event(child_event, child_ctx, child);
11262 mutex_unlock(&child_ctx->mutex);
11264 put_ctx(child_ctx);
11268 * When a child task exits, feed back event values to parent events.
11270 * Can be called with cred_guard_mutex held when called from
11271 * install_exec_creds().
11273 void perf_event_exit_task(struct task_struct *child)
11275 struct perf_event *event, *tmp;
11278 mutex_lock(&child->perf_event_mutex);
11279 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
11281 list_del_init(&event->owner_entry);
11284 * Ensure the list deletion is visible before we clear
11285 * the owner, closes a race against perf_release() where
11286 * we need to serialize on the owner->perf_event_mutex.
11288 smp_store_release(&event->owner, NULL);
11290 mutex_unlock(&child->perf_event_mutex);
11292 for_each_task_context_nr(ctxn)
11293 perf_event_exit_task_context(child, ctxn);
11296 * The perf_event_exit_task_context calls perf_event_task
11297 * with child's task_ctx, which generates EXIT events for
11298 * child contexts and sets child->perf_event_ctxp[] to NULL.
11299 * At this point we need to send EXIT events to cpu contexts.
11301 perf_event_task(child, NULL, 0);
11304 static void perf_free_event(struct perf_event *event,
11305 struct perf_event_context *ctx)
11307 struct perf_event *parent = event->parent;
11309 if (WARN_ON_ONCE(!parent))
11312 mutex_lock(&parent->child_mutex);
11313 list_del_init(&event->child_list);
11314 mutex_unlock(&parent->child_mutex);
11318 raw_spin_lock_irq(&ctx->lock);
11319 perf_group_detach(event);
11320 list_del_event(event, ctx);
11321 raw_spin_unlock_irq(&ctx->lock);
11326 * Free a context as created by inheritance by perf_event_init_task() below,
11327 * used by fork() in case of fail.
11329 * Even though the task has never lived, the context and events have been
11330 * exposed through the child_list, so we must take care tearing it all down.
11332 void perf_event_free_task(struct task_struct *task)
11334 struct perf_event_context *ctx;
11335 struct perf_event *event, *tmp;
11338 for_each_task_context_nr(ctxn) {
11339 ctx = task->perf_event_ctxp[ctxn];
11343 mutex_lock(&ctx->mutex);
11344 raw_spin_lock_irq(&ctx->lock);
11346 * Destroy the task <-> ctx relation and mark the context dead.
11348 * This is important because even though the task hasn't been
11349 * exposed yet the context has been (through child_list).
11351 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
11352 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
11353 put_task_struct(task); /* cannot be last */
11354 raw_spin_unlock_irq(&ctx->lock);
11356 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
11357 perf_free_event(event, ctx);
11359 mutex_unlock(&ctx->mutex);
11362 * perf_event_release_kernel() could've stolen some of our
11363 * child events and still have them on its free_list. In that
11364 * case we must wait for these events to have been freed (in
11365 * particular all their references to this task must've been
11368 * Without this copy_process() will unconditionally free this
11369 * task (irrespective of its reference count) and
11370 * _free_event()'s put_task_struct(event->hw.target) will be a
11373 * Wait for all events to drop their context reference.
11375 wait_var_event(&ctx->refcount, atomic_read(&ctx->refcount) == 1);
11376 put_ctx(ctx); /* must be last */
11380 void perf_event_delayed_put(struct task_struct *task)
11384 for_each_task_context_nr(ctxn)
11385 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
11388 struct file *perf_event_get(unsigned int fd)
11392 file = fget_raw(fd);
11394 return ERR_PTR(-EBADF);
11396 if (file->f_op != &perf_fops) {
11398 return ERR_PTR(-EBADF);
11404 const struct perf_event *perf_get_event(struct file *file)
11406 if (file->f_op != &perf_fops)
11407 return ERR_PTR(-EINVAL);
11409 return file->private_data;
11412 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
11415 return ERR_PTR(-EINVAL);
11417 return &event->attr;
11421 * Inherit an event from parent task to child task.
11424 * - valid pointer on success
11425 * - NULL for orphaned events
11426 * - IS_ERR() on error
11428 static struct perf_event *
11429 inherit_event(struct perf_event *parent_event,
11430 struct task_struct *parent,
11431 struct perf_event_context *parent_ctx,
11432 struct task_struct *child,
11433 struct perf_event *group_leader,
11434 struct perf_event_context *child_ctx)
11436 enum perf_event_state parent_state = parent_event->state;
11437 struct perf_event *child_event;
11438 unsigned long flags;
11441 * Instead of creating recursive hierarchies of events,
11442 * we link inherited events back to the original parent,
11443 * which has a filp for sure, which we use as the reference
11446 if (parent_event->parent)
11447 parent_event = parent_event->parent;
11449 child_event = perf_event_alloc(&parent_event->attr,
11452 group_leader, parent_event,
11454 if (IS_ERR(child_event))
11455 return child_event;
11458 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
11459 !child_ctx->task_ctx_data) {
11460 struct pmu *pmu = child_event->pmu;
11462 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
11464 if (!child_ctx->task_ctx_data) {
11465 free_event(child_event);
11466 return ERR_PTR(-ENOMEM);
11471 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
11472 * must be under the same lock in order to serialize against
11473 * perf_event_release_kernel(), such that either we must observe
11474 * is_orphaned_event() or they will observe us on the child_list.
11476 mutex_lock(&parent_event->child_mutex);
11477 if (is_orphaned_event(parent_event) ||
11478 !atomic_long_inc_not_zero(&parent_event->refcount)) {
11479 mutex_unlock(&parent_event->child_mutex);
11480 /* task_ctx_data is freed with child_ctx */
11481 free_event(child_event);
11485 get_ctx(child_ctx);
11488 * Make the child state follow the state of the parent event,
11489 * not its attr.disabled bit. We hold the parent's mutex,
11490 * so we won't race with perf_event_{en, dis}able_family.
11492 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
11493 child_event->state = PERF_EVENT_STATE_INACTIVE;
11495 child_event->state = PERF_EVENT_STATE_OFF;
11497 if (parent_event->attr.freq) {
11498 u64 sample_period = parent_event->hw.sample_period;
11499 struct hw_perf_event *hwc = &child_event->hw;
11501 hwc->sample_period = sample_period;
11502 hwc->last_period = sample_period;
11504 local64_set(&hwc->period_left, sample_period);
11507 child_event->ctx = child_ctx;
11508 child_event->overflow_handler = parent_event->overflow_handler;
11509 child_event->overflow_handler_context
11510 = parent_event->overflow_handler_context;
11513 * Precalculate sample_data sizes
11515 perf_event__header_size(child_event);
11516 perf_event__id_header_size(child_event);
11519 * Link it up in the child's context:
11521 raw_spin_lock_irqsave(&child_ctx->lock, flags);
11522 add_event_to_ctx(child_event, child_ctx);
11523 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
11526 * Link this into the parent event's child list
11528 list_add_tail(&child_event->child_list, &parent_event->child_list);
11529 mutex_unlock(&parent_event->child_mutex);
11531 return child_event;
11535 * Inherits an event group.
11537 * This will quietly suppress orphaned events; !inherit_event() is not an error.
11538 * This matches with perf_event_release_kernel() removing all child events.
11544 static int inherit_group(struct perf_event *parent_event,
11545 struct task_struct *parent,
11546 struct perf_event_context *parent_ctx,
11547 struct task_struct *child,
11548 struct perf_event_context *child_ctx)
11550 struct perf_event *leader;
11551 struct perf_event *sub;
11552 struct perf_event *child_ctr;
11554 leader = inherit_event(parent_event, parent, parent_ctx,
11555 child, NULL, child_ctx);
11556 if (IS_ERR(leader))
11557 return PTR_ERR(leader);
11559 * @leader can be NULL here because of is_orphaned_event(). In this
11560 * case inherit_event() will create individual events, similar to what
11561 * perf_group_detach() would do anyway.
11563 for_each_sibling_event(sub, parent_event) {
11564 child_ctr = inherit_event(sub, parent, parent_ctx,
11565 child, leader, child_ctx);
11566 if (IS_ERR(child_ctr))
11567 return PTR_ERR(child_ctr);
11573 * Creates the child task context and tries to inherit the event-group.
11575 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
11576 * inherited_all set when we 'fail' to inherit an orphaned event; this is
11577 * consistent with perf_event_release_kernel() removing all child events.
11584 inherit_task_group(struct perf_event *event, struct task_struct *parent,
11585 struct perf_event_context *parent_ctx,
11586 struct task_struct *child, int ctxn,
11587 int *inherited_all)
11590 struct perf_event_context *child_ctx;
11592 if (!event->attr.inherit) {
11593 *inherited_all = 0;
11597 child_ctx = child->perf_event_ctxp[ctxn];
11600 * This is executed from the parent task context, so
11601 * inherit events that have been marked for cloning.
11602 * First allocate and initialize a context for the
11605 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
11609 child->perf_event_ctxp[ctxn] = child_ctx;
11612 ret = inherit_group(event, parent, parent_ctx,
11616 *inherited_all = 0;
11622 * Initialize the perf_event context in task_struct
11624 static int perf_event_init_context(struct task_struct *child, int ctxn)
11626 struct perf_event_context *child_ctx, *parent_ctx;
11627 struct perf_event_context *cloned_ctx;
11628 struct perf_event *event;
11629 struct task_struct *parent = current;
11630 int inherited_all = 1;
11631 unsigned long flags;
11634 if (likely(!parent->perf_event_ctxp[ctxn]))
11638 * If the parent's context is a clone, pin it so it won't get
11639 * swapped under us.
11641 parent_ctx = perf_pin_task_context(parent, ctxn);
11646 * No need to check if parent_ctx != NULL here; since we saw
11647 * it non-NULL earlier, the only reason for it to become NULL
11648 * is if we exit, and since we're currently in the middle of
11649 * a fork we can't be exiting at the same time.
11653 * Lock the parent list. No need to lock the child - not PID
11654 * hashed yet and not running, so nobody can access it.
11656 mutex_lock(&parent_ctx->mutex);
11659 * We dont have to disable NMIs - we are only looking at
11660 * the list, not manipulating it:
11662 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
11663 ret = inherit_task_group(event, parent, parent_ctx,
11664 child, ctxn, &inherited_all);
11670 * We can't hold ctx->lock when iterating the ->flexible_group list due
11671 * to allocations, but we need to prevent rotation because
11672 * rotate_ctx() will change the list from interrupt context.
11674 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11675 parent_ctx->rotate_disable = 1;
11676 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11678 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
11679 ret = inherit_task_group(event, parent, parent_ctx,
11680 child, ctxn, &inherited_all);
11685 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11686 parent_ctx->rotate_disable = 0;
11688 child_ctx = child->perf_event_ctxp[ctxn];
11690 if (child_ctx && inherited_all) {
11692 * Mark the child context as a clone of the parent
11693 * context, or of whatever the parent is a clone of.
11695 * Note that if the parent is a clone, the holding of
11696 * parent_ctx->lock avoids it from being uncloned.
11698 cloned_ctx = parent_ctx->parent_ctx;
11700 child_ctx->parent_ctx = cloned_ctx;
11701 child_ctx->parent_gen = parent_ctx->parent_gen;
11703 child_ctx->parent_ctx = parent_ctx;
11704 child_ctx->parent_gen = parent_ctx->generation;
11706 get_ctx(child_ctx->parent_ctx);
11709 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11711 mutex_unlock(&parent_ctx->mutex);
11713 perf_unpin_context(parent_ctx);
11714 put_ctx(parent_ctx);
11720 * Initialize the perf_event context in task_struct
11722 int perf_event_init_task(struct task_struct *child)
11726 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
11727 mutex_init(&child->perf_event_mutex);
11728 INIT_LIST_HEAD(&child->perf_event_list);
11730 for_each_task_context_nr(ctxn) {
11731 ret = perf_event_init_context(child, ctxn);
11733 perf_event_free_task(child);
11741 static void __init perf_event_init_all_cpus(void)
11743 struct swevent_htable *swhash;
11746 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
11748 for_each_possible_cpu(cpu) {
11749 swhash = &per_cpu(swevent_htable, cpu);
11750 mutex_init(&swhash->hlist_mutex);
11751 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
11753 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
11754 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
11756 #ifdef CONFIG_CGROUP_PERF
11757 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
11759 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
11763 void perf_swevent_init_cpu(unsigned int cpu)
11765 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
11767 mutex_lock(&swhash->hlist_mutex);
11768 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11769 struct swevent_hlist *hlist;
11771 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11773 rcu_assign_pointer(swhash->swevent_hlist, hlist);
11775 mutex_unlock(&swhash->hlist_mutex);
11778 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11779 static void __perf_event_exit_context(void *__info)
11781 struct perf_event_context *ctx = __info;
11782 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11783 struct perf_event *event;
11785 raw_spin_lock(&ctx->lock);
11786 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
11787 list_for_each_entry(event, &ctx->event_list, event_entry)
11788 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11789 raw_spin_unlock(&ctx->lock);
11792 static void perf_event_exit_cpu_context(int cpu)
11794 struct perf_cpu_context *cpuctx;
11795 struct perf_event_context *ctx;
11798 mutex_lock(&pmus_lock);
11799 list_for_each_entry(pmu, &pmus, entry) {
11800 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11801 ctx = &cpuctx->ctx;
11803 mutex_lock(&ctx->mutex);
11804 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11805 cpuctx->online = 0;
11806 mutex_unlock(&ctx->mutex);
11808 cpumask_clear_cpu(cpu, perf_online_mask);
11809 mutex_unlock(&pmus_lock);
11813 static void perf_event_exit_cpu_context(int cpu) { }
11817 int perf_event_init_cpu(unsigned int cpu)
11819 struct perf_cpu_context *cpuctx;
11820 struct perf_event_context *ctx;
11823 perf_swevent_init_cpu(cpu);
11825 mutex_lock(&pmus_lock);
11826 cpumask_set_cpu(cpu, perf_online_mask);
11827 list_for_each_entry(pmu, &pmus, entry) {
11828 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11829 ctx = &cpuctx->ctx;
11831 mutex_lock(&ctx->mutex);
11832 cpuctx->online = 1;
11833 mutex_unlock(&ctx->mutex);
11835 mutex_unlock(&pmus_lock);
11840 int perf_event_exit_cpu(unsigned int cpu)
11842 perf_event_exit_cpu_context(cpu);
11847 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11851 for_each_online_cpu(cpu)
11852 perf_event_exit_cpu(cpu);
11858 * Run the perf reboot notifier at the very last possible moment so that
11859 * the generic watchdog code runs as long as possible.
11861 static struct notifier_block perf_reboot_notifier = {
11862 .notifier_call = perf_reboot,
11863 .priority = INT_MIN,
11866 void __init perf_event_init(void)
11870 idr_init(&pmu_idr);
11872 perf_event_init_all_cpus();
11873 init_srcu_struct(&pmus_srcu);
11874 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11875 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11876 perf_pmu_register(&perf_task_clock, NULL, -1);
11877 perf_tp_register();
11878 perf_event_init_cpu(smp_processor_id());
11879 register_reboot_notifier(&perf_reboot_notifier);
11881 ret = init_hw_breakpoint();
11882 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11885 * Build time assertion that we keep the data_head at the intended
11886 * location. IOW, validation we got the __reserved[] size right.
11888 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11892 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
11895 struct perf_pmu_events_attr *pmu_attr =
11896 container_of(attr, struct perf_pmu_events_attr, attr);
11898 if (pmu_attr->event_str)
11899 return sprintf(page, "%s\n", pmu_attr->event_str);
11903 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
11905 static int __init perf_event_sysfs_init(void)
11910 mutex_lock(&pmus_lock);
11912 ret = bus_register(&pmu_bus);
11916 list_for_each_entry(pmu, &pmus, entry) {
11917 if (!pmu->name || pmu->type < 0)
11920 ret = pmu_dev_alloc(pmu);
11921 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
11923 pmu_bus_running = 1;
11927 mutex_unlock(&pmus_lock);
11931 device_initcall(perf_event_sysfs_init);
11933 #ifdef CONFIG_CGROUP_PERF
11934 static struct cgroup_subsys_state *
11935 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
11937 struct perf_cgroup *jc;
11939 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
11941 return ERR_PTR(-ENOMEM);
11943 jc->info = alloc_percpu(struct perf_cgroup_info);
11946 return ERR_PTR(-ENOMEM);
11952 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
11954 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
11956 free_percpu(jc->info);
11960 static int __perf_cgroup_move(void *info)
11962 struct task_struct *task = info;
11964 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
11969 static void perf_cgroup_attach(struct cgroup_taskset *tset)
11971 struct task_struct *task;
11972 struct cgroup_subsys_state *css;
11974 cgroup_taskset_for_each(task, css, tset)
11975 task_function_call(task, __perf_cgroup_move, task);
11978 struct cgroup_subsys perf_event_cgrp_subsys = {
11979 .css_alloc = perf_cgroup_css_alloc,
11980 .css_free = perf_cgroup_css_free,
11981 .attach = perf_cgroup_attach,
11983 * Implicitly enable on dfl hierarchy so that perf events can
11984 * always be filtered by cgroup2 path as long as perf_event
11985 * controller is not mounted on a legacy hierarchy.
11987 .implicit_on_dfl = true,
11990 #endif /* CONFIG_CGROUP_PERF */