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;
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(cpuctx, 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) {
2090 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2091 cpuctx->task_ctx = NULL;
2097 * Remove the event from a task's (or a CPU's) list of events.
2099 * If event->ctx is a cloned context, callers must make sure that
2100 * every task struct that event->ctx->task could possibly point to
2101 * remains valid. This is OK when called from perf_release since
2102 * that only calls us on the top-level context, which can't be a clone.
2103 * When called from perf_event_exit_task, it's OK because the
2104 * context has been detached from its task.
2106 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2108 struct perf_event_context *ctx = event->ctx;
2110 lockdep_assert_held(&ctx->mutex);
2112 event_function_call(event, __perf_remove_from_context, (void *)flags);
2115 * The above event_function_call() can NO-OP when it hits
2116 * TASK_TOMBSTONE. In that case we must already have been detached
2117 * from the context (by perf_event_exit_event()) but the grouping
2118 * might still be in-tact.
2120 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
2121 if ((flags & DETACH_GROUP) &&
2122 (event->attach_state & PERF_ATTACH_GROUP)) {
2124 * Since in that case we cannot possibly be scheduled, simply
2127 raw_spin_lock_irq(&ctx->lock);
2128 perf_group_detach(event);
2129 raw_spin_unlock_irq(&ctx->lock);
2134 * Cross CPU call to disable a performance event
2136 static void __perf_event_disable(struct perf_event *event,
2137 struct perf_cpu_context *cpuctx,
2138 struct perf_event_context *ctx,
2141 if (event->state < PERF_EVENT_STATE_INACTIVE)
2144 if (ctx->is_active & EVENT_TIME) {
2145 update_context_time(ctx);
2146 update_cgrp_time_from_event(event);
2149 if (event == event->group_leader)
2150 group_sched_out(event, cpuctx, ctx);
2152 event_sched_out(event, cpuctx, ctx);
2154 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2160 * If event->ctx is a cloned context, callers must make sure that
2161 * every task struct that event->ctx->task could possibly point to
2162 * remains valid. This condition is satisifed when called through
2163 * perf_event_for_each_child or perf_event_for_each because they
2164 * hold the top-level event's child_mutex, so any descendant that
2165 * goes to exit will block in perf_event_exit_event().
2167 * When called from perf_pending_event it's OK because event->ctx
2168 * is the current context on this CPU and preemption is disabled,
2169 * hence we can't get into perf_event_task_sched_out for this context.
2171 static void _perf_event_disable(struct perf_event *event)
2173 struct perf_event_context *ctx = event->ctx;
2175 raw_spin_lock_irq(&ctx->lock);
2176 if (event->state <= PERF_EVENT_STATE_OFF) {
2177 raw_spin_unlock_irq(&ctx->lock);
2180 raw_spin_unlock_irq(&ctx->lock);
2182 event_function_call(event, __perf_event_disable, NULL);
2185 void perf_event_disable_local(struct perf_event *event)
2187 event_function_local(event, __perf_event_disable, NULL);
2191 * Strictly speaking kernel users cannot create groups and therefore this
2192 * interface does not need the perf_event_ctx_lock() magic.
2194 void perf_event_disable(struct perf_event *event)
2196 struct perf_event_context *ctx;
2198 ctx = perf_event_ctx_lock(event);
2199 _perf_event_disable(event);
2200 perf_event_ctx_unlock(event, ctx);
2202 EXPORT_SYMBOL_GPL(perf_event_disable);
2204 void perf_event_disable_inatomic(struct perf_event *event)
2206 WRITE_ONCE(event->pending_disable, smp_processor_id());
2207 /* can fail, see perf_pending_event_disable() */
2208 irq_work_queue(&event->pending);
2211 static void perf_set_shadow_time(struct perf_event *event,
2212 struct perf_event_context *ctx)
2215 * use the correct time source for the time snapshot
2217 * We could get by without this by leveraging the
2218 * fact that to get to this function, the caller
2219 * has most likely already called update_context_time()
2220 * and update_cgrp_time_xx() and thus both timestamp
2221 * are identical (or very close). Given that tstamp is,
2222 * already adjusted for cgroup, we could say that:
2223 * tstamp - ctx->timestamp
2225 * tstamp - cgrp->timestamp.
2227 * Then, in perf_output_read(), the calculation would
2228 * work with no changes because:
2229 * - event is guaranteed scheduled in
2230 * - no scheduled out in between
2231 * - thus the timestamp would be the same
2233 * But this is a bit hairy.
2235 * So instead, we have an explicit cgroup call to remain
2236 * within the time time source all along. We believe it
2237 * is cleaner and simpler to understand.
2239 if (is_cgroup_event(event))
2240 perf_cgroup_set_shadow_time(event, event->tstamp);
2242 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2245 #define MAX_INTERRUPTS (~0ULL)
2247 static void perf_log_throttle(struct perf_event *event, int enable);
2248 static void perf_log_itrace_start(struct perf_event *event);
2251 event_sched_in(struct perf_event *event,
2252 struct perf_cpu_context *cpuctx,
2253 struct perf_event_context *ctx)
2257 lockdep_assert_held(&ctx->lock);
2259 if (event->state <= PERF_EVENT_STATE_OFF)
2262 WRITE_ONCE(event->oncpu, smp_processor_id());
2264 * Order event::oncpu write to happen before the ACTIVE state is
2265 * visible. This allows perf_event_{stop,read}() to observe the correct
2266 * ->oncpu if it sees ACTIVE.
2269 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2272 * Unthrottle events, since we scheduled we might have missed several
2273 * ticks already, also for a heavily scheduling task there is little
2274 * guarantee it'll get a tick in a timely manner.
2276 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2277 perf_log_throttle(event, 1);
2278 event->hw.interrupts = 0;
2281 perf_pmu_disable(event->pmu);
2283 perf_set_shadow_time(event, ctx);
2285 perf_log_itrace_start(event);
2287 if (event->pmu->add(event, PERF_EF_START)) {
2288 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2294 if (!is_software_event(event))
2295 cpuctx->active_oncpu++;
2296 if (!ctx->nr_active++)
2297 perf_event_ctx_activate(ctx);
2298 if (event->attr.freq && event->attr.sample_freq)
2301 if (event->attr.exclusive)
2302 cpuctx->exclusive = 1;
2305 perf_pmu_enable(event->pmu);
2311 group_sched_in(struct perf_event *group_event,
2312 struct perf_cpu_context *cpuctx,
2313 struct perf_event_context *ctx)
2315 struct perf_event *event, *partial_group = NULL;
2316 struct pmu *pmu = ctx->pmu;
2318 if (group_event->state == PERF_EVENT_STATE_OFF)
2321 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2323 if (event_sched_in(group_event, cpuctx, ctx)) {
2324 pmu->cancel_txn(pmu);
2325 perf_mux_hrtimer_restart(cpuctx);
2330 * Schedule in siblings as one group (if any):
2332 for_each_sibling_event(event, group_event) {
2333 if (event_sched_in(event, cpuctx, ctx)) {
2334 partial_group = event;
2339 if (!pmu->commit_txn(pmu))
2344 * Groups can be scheduled in as one unit only, so undo any
2345 * partial group before returning:
2346 * The events up to the failed event are scheduled out normally.
2348 for_each_sibling_event(event, group_event) {
2349 if (event == partial_group)
2352 event_sched_out(event, cpuctx, ctx);
2354 event_sched_out(group_event, cpuctx, ctx);
2356 pmu->cancel_txn(pmu);
2358 perf_mux_hrtimer_restart(cpuctx);
2364 * Work out whether we can put this event group on the CPU now.
2366 static int group_can_go_on(struct perf_event *event,
2367 struct perf_cpu_context *cpuctx,
2371 * Groups consisting entirely of software events can always go on.
2373 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2376 * If an exclusive group is already on, no other hardware
2379 if (cpuctx->exclusive)
2382 * If this group is exclusive and there are already
2383 * events on the CPU, it can't go on.
2385 if (event->attr.exclusive && cpuctx->active_oncpu)
2388 * Otherwise, try to add it if all previous groups were able
2394 static void add_event_to_ctx(struct perf_event *event,
2395 struct perf_event_context *ctx)
2397 list_add_event(event, ctx);
2398 perf_group_attach(event);
2401 static void ctx_sched_out(struct perf_event_context *ctx,
2402 struct perf_cpu_context *cpuctx,
2403 enum event_type_t event_type);
2405 ctx_sched_in(struct perf_event_context *ctx,
2406 struct perf_cpu_context *cpuctx,
2407 enum event_type_t event_type,
2408 struct task_struct *task);
2410 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2411 struct perf_event_context *ctx,
2412 enum event_type_t event_type)
2414 if (!cpuctx->task_ctx)
2417 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2420 ctx_sched_out(ctx, cpuctx, event_type);
2423 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2424 struct perf_event_context *ctx,
2425 struct task_struct *task)
2427 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2429 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2430 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2432 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2436 * We want to maintain the following priority of scheduling:
2437 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2438 * - task pinned (EVENT_PINNED)
2439 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2440 * - task flexible (EVENT_FLEXIBLE).
2442 * In order to avoid unscheduling and scheduling back in everything every
2443 * time an event is added, only do it for the groups of equal priority and
2446 * This can be called after a batch operation on task events, in which case
2447 * event_type is a bit mask of the types of events involved. For CPU events,
2448 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2450 static void ctx_resched(struct perf_cpu_context *cpuctx,
2451 struct perf_event_context *task_ctx,
2452 enum event_type_t event_type)
2454 enum event_type_t ctx_event_type;
2455 bool cpu_event = !!(event_type & EVENT_CPU);
2458 * If pinned groups are involved, flexible groups also need to be
2461 if (event_type & EVENT_PINNED)
2462 event_type |= EVENT_FLEXIBLE;
2464 ctx_event_type = event_type & EVENT_ALL;
2466 perf_pmu_disable(cpuctx->ctx.pmu);
2468 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2471 * Decide which cpu ctx groups to schedule out based on the types
2472 * of events that caused rescheduling:
2473 * - EVENT_CPU: schedule out corresponding groups;
2474 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2475 * - otherwise, do nothing more.
2478 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2479 else if (ctx_event_type & EVENT_PINNED)
2480 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2482 perf_event_sched_in(cpuctx, task_ctx, current);
2483 perf_pmu_enable(cpuctx->ctx.pmu);
2487 * Cross CPU call to install and enable a performance event
2489 * Very similar to remote_function() + event_function() but cannot assume that
2490 * things like ctx->is_active and cpuctx->task_ctx are set.
2492 static int __perf_install_in_context(void *info)
2494 struct perf_event *event = info;
2495 struct perf_event_context *ctx = event->ctx;
2496 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2497 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2498 bool reprogram = true;
2501 raw_spin_lock(&cpuctx->ctx.lock);
2503 raw_spin_lock(&ctx->lock);
2506 reprogram = (ctx->task == current);
2509 * If the task is running, it must be running on this CPU,
2510 * otherwise we cannot reprogram things.
2512 * If its not running, we don't care, ctx->lock will
2513 * serialize against it becoming runnable.
2515 if (task_curr(ctx->task) && !reprogram) {
2520 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2521 } else if (task_ctx) {
2522 raw_spin_lock(&task_ctx->lock);
2525 #ifdef CONFIG_CGROUP_PERF
2526 if (is_cgroup_event(event)) {
2528 * If the current cgroup doesn't match the event's
2529 * cgroup, we should not try to schedule it.
2531 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2532 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2533 event->cgrp->css.cgroup);
2538 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2539 add_event_to_ctx(event, ctx);
2540 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2542 add_event_to_ctx(event, ctx);
2546 perf_ctx_unlock(cpuctx, task_ctx);
2551 static bool exclusive_event_installable(struct perf_event *event,
2552 struct perf_event_context *ctx);
2555 * Attach a performance event to a context.
2557 * Very similar to event_function_call, see comment there.
2560 perf_install_in_context(struct perf_event_context *ctx,
2561 struct perf_event *event,
2564 struct task_struct *task = READ_ONCE(ctx->task);
2566 lockdep_assert_held(&ctx->mutex);
2568 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2570 if (event->cpu != -1)
2574 * Ensures that if we can observe event->ctx, both the event and ctx
2575 * will be 'complete'. See perf_iterate_sb_cpu().
2577 smp_store_release(&event->ctx, ctx);
2580 cpu_function_call(cpu, __perf_install_in_context, event);
2585 * Should not happen, we validate the ctx is still alive before calling.
2587 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2591 * Installing events is tricky because we cannot rely on ctx->is_active
2592 * to be set in case this is the nr_events 0 -> 1 transition.
2594 * Instead we use task_curr(), which tells us if the task is running.
2595 * However, since we use task_curr() outside of rq::lock, we can race
2596 * against the actual state. This means the result can be wrong.
2598 * If we get a false positive, we retry, this is harmless.
2600 * If we get a false negative, things are complicated. If we are after
2601 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2602 * value must be correct. If we're before, it doesn't matter since
2603 * perf_event_context_sched_in() will program the counter.
2605 * However, this hinges on the remote context switch having observed
2606 * our task->perf_event_ctxp[] store, such that it will in fact take
2607 * ctx::lock in perf_event_context_sched_in().
2609 * We do this by task_function_call(), if the IPI fails to hit the task
2610 * we know any future context switch of task must see the
2611 * perf_event_ctpx[] store.
2615 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2616 * task_cpu() load, such that if the IPI then does not find the task
2617 * running, a future context switch of that task must observe the
2622 if (!task_function_call(task, __perf_install_in_context, event))
2625 raw_spin_lock_irq(&ctx->lock);
2627 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2629 * Cannot happen because we already checked above (which also
2630 * cannot happen), and we hold ctx->mutex, which serializes us
2631 * against perf_event_exit_task_context().
2633 raw_spin_unlock_irq(&ctx->lock);
2637 * If the task is not running, ctx->lock will avoid it becoming so,
2638 * thus we can safely install the event.
2640 if (task_curr(task)) {
2641 raw_spin_unlock_irq(&ctx->lock);
2644 add_event_to_ctx(event, ctx);
2645 raw_spin_unlock_irq(&ctx->lock);
2649 * Cross CPU call to enable a performance event
2651 static void __perf_event_enable(struct perf_event *event,
2652 struct perf_cpu_context *cpuctx,
2653 struct perf_event_context *ctx,
2656 struct perf_event *leader = event->group_leader;
2657 struct perf_event_context *task_ctx;
2659 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2660 event->state <= PERF_EVENT_STATE_ERROR)
2664 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2666 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2668 if (!ctx->is_active)
2671 if (!event_filter_match(event)) {
2672 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2677 * If the event is in a group and isn't the group leader,
2678 * then don't put it on unless the group is on.
2680 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2681 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2685 task_ctx = cpuctx->task_ctx;
2687 WARN_ON_ONCE(task_ctx != ctx);
2689 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2695 * If event->ctx is a cloned context, callers must make sure that
2696 * every task struct that event->ctx->task could possibly point to
2697 * remains valid. This condition is satisfied when called through
2698 * perf_event_for_each_child or perf_event_for_each as described
2699 * for perf_event_disable.
2701 static void _perf_event_enable(struct perf_event *event)
2703 struct perf_event_context *ctx = event->ctx;
2705 raw_spin_lock_irq(&ctx->lock);
2706 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2707 event->state < PERF_EVENT_STATE_ERROR) {
2708 raw_spin_unlock_irq(&ctx->lock);
2713 * If the event is in error state, clear that first.
2715 * That way, if we see the event in error state below, we know that it
2716 * has gone back into error state, as distinct from the task having
2717 * been scheduled away before the cross-call arrived.
2719 if (event->state == PERF_EVENT_STATE_ERROR)
2720 event->state = PERF_EVENT_STATE_OFF;
2721 raw_spin_unlock_irq(&ctx->lock);
2723 event_function_call(event, __perf_event_enable, NULL);
2727 * See perf_event_disable();
2729 void perf_event_enable(struct perf_event *event)
2731 struct perf_event_context *ctx;
2733 ctx = perf_event_ctx_lock(event);
2734 _perf_event_enable(event);
2735 perf_event_ctx_unlock(event, ctx);
2737 EXPORT_SYMBOL_GPL(perf_event_enable);
2739 struct stop_event_data {
2740 struct perf_event *event;
2741 unsigned int restart;
2744 static int __perf_event_stop(void *info)
2746 struct stop_event_data *sd = info;
2747 struct perf_event *event = sd->event;
2749 /* if it's already INACTIVE, do nothing */
2750 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2753 /* matches smp_wmb() in event_sched_in() */
2757 * There is a window with interrupts enabled before we get here,
2758 * so we need to check again lest we try to stop another CPU's event.
2760 if (READ_ONCE(event->oncpu) != smp_processor_id())
2763 event->pmu->stop(event, PERF_EF_UPDATE);
2766 * May race with the actual stop (through perf_pmu_output_stop()),
2767 * but it is only used for events with AUX ring buffer, and such
2768 * events will refuse to restart because of rb::aux_mmap_count==0,
2769 * see comments in perf_aux_output_begin().
2771 * Since this is happening on an event-local CPU, no trace is lost
2775 event->pmu->start(event, 0);
2780 static int perf_event_stop(struct perf_event *event, int restart)
2782 struct stop_event_data sd = {
2789 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2792 /* matches smp_wmb() in event_sched_in() */
2796 * We only want to restart ACTIVE events, so if the event goes
2797 * inactive here (event->oncpu==-1), there's nothing more to do;
2798 * fall through with ret==-ENXIO.
2800 ret = cpu_function_call(READ_ONCE(event->oncpu),
2801 __perf_event_stop, &sd);
2802 } while (ret == -EAGAIN);
2808 * In order to contain the amount of racy and tricky in the address filter
2809 * configuration management, it is a two part process:
2811 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2812 * we update the addresses of corresponding vmas in
2813 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
2814 * (p2) when an event is scheduled in (pmu::add), it calls
2815 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2816 * if the generation has changed since the previous call.
2818 * If (p1) happens while the event is active, we restart it to force (p2).
2820 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2821 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2823 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2824 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2826 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2829 void perf_event_addr_filters_sync(struct perf_event *event)
2831 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2833 if (!has_addr_filter(event))
2836 raw_spin_lock(&ifh->lock);
2837 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2838 event->pmu->addr_filters_sync(event);
2839 event->hw.addr_filters_gen = event->addr_filters_gen;
2841 raw_spin_unlock(&ifh->lock);
2843 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2845 static int _perf_event_refresh(struct perf_event *event, int refresh)
2848 * not supported on inherited events
2850 if (event->attr.inherit || !is_sampling_event(event))
2853 atomic_add(refresh, &event->event_limit);
2854 _perf_event_enable(event);
2860 * See perf_event_disable()
2862 int perf_event_refresh(struct perf_event *event, int refresh)
2864 struct perf_event_context *ctx;
2867 ctx = perf_event_ctx_lock(event);
2868 ret = _perf_event_refresh(event, refresh);
2869 perf_event_ctx_unlock(event, ctx);
2873 EXPORT_SYMBOL_GPL(perf_event_refresh);
2875 static int perf_event_modify_breakpoint(struct perf_event *bp,
2876 struct perf_event_attr *attr)
2880 _perf_event_disable(bp);
2882 err = modify_user_hw_breakpoint_check(bp, attr, true);
2884 if (!bp->attr.disabled)
2885 _perf_event_enable(bp);
2890 static int perf_event_modify_attr(struct perf_event *event,
2891 struct perf_event_attr *attr)
2893 if (event->attr.type != attr->type)
2896 switch (event->attr.type) {
2897 case PERF_TYPE_BREAKPOINT:
2898 return perf_event_modify_breakpoint(event, attr);
2900 /* Place holder for future additions. */
2905 static void ctx_sched_out(struct perf_event_context *ctx,
2906 struct perf_cpu_context *cpuctx,
2907 enum event_type_t event_type)
2909 struct perf_event *event, *tmp;
2910 int is_active = ctx->is_active;
2912 lockdep_assert_held(&ctx->lock);
2914 if (likely(!ctx->nr_events)) {
2916 * See __perf_remove_from_context().
2918 WARN_ON_ONCE(ctx->is_active);
2920 WARN_ON_ONCE(cpuctx->task_ctx);
2924 ctx->is_active &= ~event_type;
2925 if (!(ctx->is_active & EVENT_ALL))
2929 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2930 if (!ctx->is_active)
2931 cpuctx->task_ctx = NULL;
2935 * Always update time if it was set; not only when it changes.
2936 * Otherwise we can 'forget' to update time for any but the last
2937 * context we sched out. For example:
2939 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2940 * ctx_sched_out(.event_type = EVENT_PINNED)
2942 * would only update time for the pinned events.
2944 if (is_active & EVENT_TIME) {
2945 /* update (and stop) ctx time */
2946 update_context_time(ctx);
2947 update_cgrp_time_from_cpuctx(cpuctx);
2950 is_active ^= ctx->is_active; /* changed bits */
2952 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2956 * If we had been multiplexing, no rotations are necessary, now no events
2959 ctx->rotate_necessary = 0;
2961 perf_pmu_disable(ctx->pmu);
2962 if (is_active & EVENT_PINNED) {
2963 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
2964 group_sched_out(event, cpuctx, ctx);
2967 if (is_active & EVENT_FLEXIBLE) {
2968 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
2969 group_sched_out(event, cpuctx, ctx);
2971 perf_pmu_enable(ctx->pmu);
2975 * Test whether two contexts are equivalent, i.e. whether they have both been
2976 * cloned from the same version of the same context.
2978 * Equivalence is measured using a generation number in the context that is
2979 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2980 * and list_del_event().
2982 static int context_equiv(struct perf_event_context *ctx1,
2983 struct perf_event_context *ctx2)
2985 lockdep_assert_held(&ctx1->lock);
2986 lockdep_assert_held(&ctx2->lock);
2988 /* Pinning disables the swap optimization */
2989 if (ctx1->pin_count || ctx2->pin_count)
2992 /* If ctx1 is the parent of ctx2 */
2993 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2996 /* If ctx2 is the parent of ctx1 */
2997 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3001 * If ctx1 and ctx2 have the same parent; we flatten the parent
3002 * hierarchy, see perf_event_init_context().
3004 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3005 ctx1->parent_gen == ctx2->parent_gen)
3012 static void __perf_event_sync_stat(struct perf_event *event,
3013 struct perf_event *next_event)
3017 if (!event->attr.inherit_stat)
3021 * Update the event value, we cannot use perf_event_read()
3022 * because we're in the middle of a context switch and have IRQs
3023 * disabled, which upsets smp_call_function_single(), however
3024 * we know the event must be on the current CPU, therefore we
3025 * don't need to use it.
3027 if (event->state == PERF_EVENT_STATE_ACTIVE)
3028 event->pmu->read(event);
3030 perf_event_update_time(event);
3033 * In order to keep per-task stats reliable we need to flip the event
3034 * values when we flip the contexts.
3036 value = local64_read(&next_event->count);
3037 value = local64_xchg(&event->count, value);
3038 local64_set(&next_event->count, value);
3040 swap(event->total_time_enabled, next_event->total_time_enabled);
3041 swap(event->total_time_running, next_event->total_time_running);
3044 * Since we swizzled the values, update the user visible data too.
3046 perf_event_update_userpage(event);
3047 perf_event_update_userpage(next_event);
3050 static void perf_event_sync_stat(struct perf_event_context *ctx,
3051 struct perf_event_context *next_ctx)
3053 struct perf_event *event, *next_event;
3058 update_context_time(ctx);
3060 event = list_first_entry(&ctx->event_list,
3061 struct perf_event, event_entry);
3063 next_event = list_first_entry(&next_ctx->event_list,
3064 struct perf_event, event_entry);
3066 while (&event->event_entry != &ctx->event_list &&
3067 &next_event->event_entry != &next_ctx->event_list) {
3069 __perf_event_sync_stat(event, next_event);
3071 event = list_next_entry(event, event_entry);
3072 next_event = list_next_entry(next_event, event_entry);
3076 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3077 struct task_struct *next)
3079 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3080 struct perf_event_context *next_ctx;
3081 struct perf_event_context *parent, *next_parent;
3082 struct perf_cpu_context *cpuctx;
3088 cpuctx = __get_cpu_context(ctx);
3089 if (!cpuctx->task_ctx)
3093 next_ctx = next->perf_event_ctxp[ctxn];
3097 parent = rcu_dereference(ctx->parent_ctx);
3098 next_parent = rcu_dereference(next_ctx->parent_ctx);
3100 /* If neither context have a parent context; they cannot be clones. */
3101 if (!parent && !next_parent)
3104 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3106 * Looks like the two contexts are clones, so we might be
3107 * able to optimize the context switch. We lock both
3108 * contexts and check that they are clones under the
3109 * lock (including re-checking that neither has been
3110 * uncloned in the meantime). It doesn't matter which
3111 * order we take the locks because no other cpu could
3112 * be trying to lock both of these tasks.
3114 raw_spin_lock(&ctx->lock);
3115 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3116 if (context_equiv(ctx, next_ctx)) {
3117 WRITE_ONCE(ctx->task, next);
3118 WRITE_ONCE(next_ctx->task, task);
3120 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3123 * RCU_INIT_POINTER here is safe because we've not
3124 * modified the ctx and the above modification of
3125 * ctx->task and ctx->task_ctx_data are immaterial
3126 * since those values are always verified under
3127 * ctx->lock which we're now holding.
3129 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3130 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3134 perf_event_sync_stat(ctx, next_ctx);
3136 raw_spin_unlock(&next_ctx->lock);
3137 raw_spin_unlock(&ctx->lock);
3143 raw_spin_lock(&ctx->lock);
3144 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3145 raw_spin_unlock(&ctx->lock);
3149 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3151 void perf_sched_cb_dec(struct pmu *pmu)
3153 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3155 this_cpu_dec(perf_sched_cb_usages);
3157 if (!--cpuctx->sched_cb_usage)
3158 list_del(&cpuctx->sched_cb_entry);
3162 void perf_sched_cb_inc(struct pmu *pmu)
3164 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3166 if (!cpuctx->sched_cb_usage++)
3167 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3169 this_cpu_inc(perf_sched_cb_usages);
3173 * This function provides the context switch callback to the lower code
3174 * layer. It is invoked ONLY when the context switch callback is enabled.
3176 * This callback is relevant even to per-cpu events; for example multi event
3177 * PEBS requires this to provide PID/TID information. This requires we flush
3178 * all queued PEBS records before we context switch to a new task.
3180 static void perf_pmu_sched_task(struct task_struct *prev,
3181 struct task_struct *next,
3184 struct perf_cpu_context *cpuctx;
3190 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3191 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3193 if (WARN_ON_ONCE(!pmu->sched_task))
3196 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3197 perf_pmu_disable(pmu);
3199 pmu->sched_task(cpuctx->task_ctx, sched_in);
3201 perf_pmu_enable(pmu);
3202 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3206 static void perf_event_switch(struct task_struct *task,
3207 struct task_struct *next_prev, bool sched_in);
3209 #define for_each_task_context_nr(ctxn) \
3210 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3213 * Called from scheduler to remove the events of the current task,
3214 * with interrupts disabled.
3216 * We stop each event and update the event value in event->count.
3218 * This does not protect us against NMI, but disable()
3219 * sets the disabled bit in the control field of event _before_
3220 * accessing the event control register. If a NMI hits, then it will
3221 * not restart the event.
3223 void __perf_event_task_sched_out(struct task_struct *task,
3224 struct task_struct *next)
3228 if (__this_cpu_read(perf_sched_cb_usages))
3229 perf_pmu_sched_task(task, next, false);
3231 if (atomic_read(&nr_switch_events))
3232 perf_event_switch(task, next, false);
3234 for_each_task_context_nr(ctxn)
3235 perf_event_context_sched_out(task, ctxn, next);
3238 * if cgroup events exist on this CPU, then we need
3239 * to check if we have to switch out PMU state.
3240 * cgroup event are system-wide mode only
3242 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3243 perf_cgroup_sched_out(task, next);
3247 * Called with IRQs disabled
3249 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3250 enum event_type_t event_type)
3252 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3255 static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
3256 int (*func)(struct perf_event *, void *), void *data)
3258 struct perf_event **evt, *evt1, *evt2;
3261 evt1 = perf_event_groups_first(groups, -1);
3262 evt2 = perf_event_groups_first(groups, cpu);
3264 while (evt1 || evt2) {
3266 if (evt1->group_index < evt2->group_index)
3276 ret = func(*evt, data);
3280 *evt = perf_event_groups_next(*evt);
3286 struct sched_in_data {
3287 struct perf_event_context *ctx;
3288 struct perf_cpu_context *cpuctx;
3292 static int pinned_sched_in(struct perf_event *event, void *data)
3294 struct sched_in_data *sid = data;
3296 if (event->state <= PERF_EVENT_STATE_OFF)
3299 if (!event_filter_match(event))
3302 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3303 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3304 list_add_tail(&event->active_list, &sid->ctx->pinned_active);
3308 * If this pinned group hasn't been scheduled,
3309 * put it in error state.
3311 if (event->state == PERF_EVENT_STATE_INACTIVE)
3312 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3317 static int flexible_sched_in(struct perf_event *event, void *data)
3319 struct sched_in_data *sid = data;
3321 if (event->state <= PERF_EVENT_STATE_OFF)
3324 if (!event_filter_match(event))
3327 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3328 int ret = group_sched_in(event, sid->cpuctx, sid->ctx);
3330 sid->can_add_hw = 0;
3331 sid->ctx->rotate_necessary = 1;
3334 list_add_tail(&event->active_list, &sid->ctx->flexible_active);
3341 ctx_pinned_sched_in(struct perf_event_context *ctx,
3342 struct perf_cpu_context *cpuctx)
3344 struct sched_in_data sid = {
3350 visit_groups_merge(&ctx->pinned_groups,
3352 pinned_sched_in, &sid);
3356 ctx_flexible_sched_in(struct perf_event_context *ctx,
3357 struct perf_cpu_context *cpuctx)
3359 struct sched_in_data sid = {
3365 visit_groups_merge(&ctx->flexible_groups,
3367 flexible_sched_in, &sid);
3371 ctx_sched_in(struct perf_event_context *ctx,
3372 struct perf_cpu_context *cpuctx,
3373 enum event_type_t event_type,
3374 struct task_struct *task)
3376 int is_active = ctx->is_active;
3379 lockdep_assert_held(&ctx->lock);
3381 if (likely(!ctx->nr_events))
3384 ctx->is_active |= (event_type | EVENT_TIME);
3387 cpuctx->task_ctx = ctx;
3389 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3392 is_active ^= ctx->is_active; /* changed bits */
3394 if (is_active & EVENT_TIME) {
3395 /* start ctx time */
3397 ctx->timestamp = now;
3398 perf_cgroup_set_timestamp(task, ctx);
3402 * First go through the list and put on any pinned groups
3403 * in order to give them the best chance of going on.
3405 if (is_active & EVENT_PINNED)
3406 ctx_pinned_sched_in(ctx, cpuctx);
3408 /* Then walk through the lower prio flexible groups */
3409 if (is_active & EVENT_FLEXIBLE)
3410 ctx_flexible_sched_in(ctx, cpuctx);
3413 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3414 enum event_type_t event_type,
3415 struct task_struct *task)
3417 struct perf_event_context *ctx = &cpuctx->ctx;
3419 ctx_sched_in(ctx, cpuctx, event_type, task);
3422 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3423 struct task_struct *task)
3425 struct perf_cpu_context *cpuctx;
3427 cpuctx = __get_cpu_context(ctx);
3428 if (cpuctx->task_ctx == ctx)
3431 perf_ctx_lock(cpuctx, ctx);
3433 * We must check ctx->nr_events while holding ctx->lock, such
3434 * that we serialize against perf_install_in_context().
3436 if (!ctx->nr_events)
3439 perf_pmu_disable(ctx->pmu);
3441 * We want to keep the following priority order:
3442 * cpu pinned (that don't need to move), task pinned,
3443 * cpu flexible, task flexible.
3445 * However, if task's ctx is not carrying any pinned
3446 * events, no need to flip the cpuctx's events around.
3448 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3449 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3450 perf_event_sched_in(cpuctx, ctx, task);
3451 perf_pmu_enable(ctx->pmu);
3454 perf_ctx_unlock(cpuctx, ctx);
3458 * Called from scheduler to add the events of the current task
3459 * with interrupts disabled.
3461 * We restore the event value and then enable it.
3463 * This does not protect us against NMI, but enable()
3464 * sets the enabled bit in the control field of event _before_
3465 * accessing the event control register. If a NMI hits, then it will
3466 * keep the event running.
3468 void __perf_event_task_sched_in(struct task_struct *prev,
3469 struct task_struct *task)
3471 struct perf_event_context *ctx;
3475 * If cgroup events exist on this CPU, then we need to check if we have
3476 * to switch in PMU state; cgroup event are system-wide mode only.
3478 * Since cgroup events are CPU events, we must schedule these in before
3479 * we schedule in the task events.
3481 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3482 perf_cgroup_sched_in(prev, task);
3484 for_each_task_context_nr(ctxn) {
3485 ctx = task->perf_event_ctxp[ctxn];
3489 perf_event_context_sched_in(ctx, task);
3492 if (atomic_read(&nr_switch_events))
3493 perf_event_switch(task, prev, true);
3495 if (__this_cpu_read(perf_sched_cb_usages))
3496 perf_pmu_sched_task(prev, task, true);
3499 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3501 u64 frequency = event->attr.sample_freq;
3502 u64 sec = NSEC_PER_SEC;
3503 u64 divisor, dividend;
3505 int count_fls, nsec_fls, frequency_fls, sec_fls;
3507 count_fls = fls64(count);
3508 nsec_fls = fls64(nsec);
3509 frequency_fls = fls64(frequency);
3513 * We got @count in @nsec, with a target of sample_freq HZ
3514 * the target period becomes:
3517 * period = -------------------
3518 * @nsec * sample_freq
3523 * Reduce accuracy by one bit such that @a and @b converge
3524 * to a similar magnitude.
3526 #define REDUCE_FLS(a, b) \
3528 if (a##_fls > b##_fls) { \
3538 * Reduce accuracy until either term fits in a u64, then proceed with
3539 * the other, so that finally we can do a u64/u64 division.
3541 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3542 REDUCE_FLS(nsec, frequency);
3543 REDUCE_FLS(sec, count);
3546 if (count_fls + sec_fls > 64) {
3547 divisor = nsec * frequency;
3549 while (count_fls + sec_fls > 64) {
3550 REDUCE_FLS(count, sec);
3554 dividend = count * sec;
3556 dividend = count * sec;
3558 while (nsec_fls + frequency_fls > 64) {
3559 REDUCE_FLS(nsec, frequency);
3563 divisor = nsec * frequency;
3569 return div64_u64(dividend, divisor);
3572 static DEFINE_PER_CPU(int, perf_throttled_count);
3573 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3575 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3577 struct hw_perf_event *hwc = &event->hw;
3578 s64 period, sample_period;
3581 period = perf_calculate_period(event, nsec, count);
3583 delta = (s64)(period - hwc->sample_period);
3584 delta = (delta + 7) / 8; /* low pass filter */
3586 sample_period = hwc->sample_period + delta;
3591 hwc->sample_period = sample_period;
3593 if (local64_read(&hwc->period_left) > 8*sample_period) {
3595 event->pmu->stop(event, PERF_EF_UPDATE);
3597 local64_set(&hwc->period_left, 0);
3600 event->pmu->start(event, PERF_EF_RELOAD);
3605 * combine freq adjustment with unthrottling to avoid two passes over the
3606 * events. At the same time, make sure, having freq events does not change
3607 * the rate of unthrottling as that would introduce bias.
3609 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3612 struct perf_event *event;
3613 struct hw_perf_event *hwc;
3614 u64 now, period = TICK_NSEC;
3618 * only need to iterate over all events iff:
3619 * - context have events in frequency mode (needs freq adjust)
3620 * - there are events to unthrottle on this cpu
3622 if (!(ctx->nr_freq || needs_unthr))
3625 raw_spin_lock(&ctx->lock);
3626 perf_pmu_disable(ctx->pmu);
3628 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3629 if (event->state != PERF_EVENT_STATE_ACTIVE)
3632 if (!event_filter_match(event))
3635 perf_pmu_disable(event->pmu);
3639 if (hwc->interrupts == MAX_INTERRUPTS) {
3640 hwc->interrupts = 0;
3641 perf_log_throttle(event, 1);
3642 event->pmu->start(event, 0);
3645 if (!event->attr.freq || !event->attr.sample_freq)
3649 * stop the event and update event->count
3651 event->pmu->stop(event, PERF_EF_UPDATE);
3653 now = local64_read(&event->count);
3654 delta = now - hwc->freq_count_stamp;
3655 hwc->freq_count_stamp = now;
3659 * reload only if value has changed
3660 * we have stopped the event so tell that
3661 * to perf_adjust_period() to avoid stopping it
3665 perf_adjust_period(event, period, delta, false);
3667 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3669 perf_pmu_enable(event->pmu);
3672 perf_pmu_enable(ctx->pmu);
3673 raw_spin_unlock(&ctx->lock);
3677 * Move @event to the tail of the @ctx's elegible events.
3679 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
3682 * Rotate the first entry last of non-pinned groups. Rotation might be
3683 * disabled by the inheritance code.
3685 if (ctx->rotate_disable)
3688 perf_event_groups_delete(&ctx->flexible_groups, event);
3689 perf_event_groups_insert(&ctx->flexible_groups, event);
3692 /* pick an event from the flexible_groups to rotate */
3693 static inline struct perf_event *
3694 ctx_event_to_rotate(struct perf_event_context *ctx)
3696 struct perf_event *event;
3698 /* pick the first active flexible event */
3699 event = list_first_entry_or_null(&ctx->flexible_active,
3700 struct perf_event, active_list);
3702 /* if no active flexible event, pick the first event */
3704 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
3705 typeof(*event), group_node);
3711 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
3713 struct perf_event *cpu_event = NULL, *task_event = NULL;
3714 struct perf_event_context *task_ctx = NULL;
3715 int cpu_rotate, task_rotate;
3718 * Since we run this from IRQ context, nobody can install new
3719 * events, thus the event count values are stable.
3722 cpu_rotate = cpuctx->ctx.rotate_necessary;
3723 task_ctx = cpuctx->task_ctx;
3724 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
3726 if (!(cpu_rotate || task_rotate))
3729 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3730 perf_pmu_disable(cpuctx->ctx.pmu);
3733 task_event = ctx_event_to_rotate(task_ctx);
3735 cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
3738 * As per the order given at ctx_resched() first 'pop' task flexible
3739 * and then, if needed CPU flexible.
3741 if (task_event || (task_ctx && cpu_event))
3742 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
3744 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3747 rotate_ctx(task_ctx, task_event);
3749 rotate_ctx(&cpuctx->ctx, cpu_event);
3751 perf_event_sched_in(cpuctx, task_ctx, current);
3753 perf_pmu_enable(cpuctx->ctx.pmu);
3754 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3759 void perf_event_task_tick(void)
3761 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3762 struct perf_event_context *ctx, *tmp;
3765 lockdep_assert_irqs_disabled();
3767 __this_cpu_inc(perf_throttled_seq);
3768 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3769 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3771 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3772 perf_adjust_freq_unthr_context(ctx, throttled);
3775 static int event_enable_on_exec(struct perf_event *event,
3776 struct perf_event_context *ctx)
3778 if (!event->attr.enable_on_exec)
3781 event->attr.enable_on_exec = 0;
3782 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3785 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3791 * Enable all of a task's events that have been marked enable-on-exec.
3792 * This expects task == current.
3794 static void perf_event_enable_on_exec(int ctxn)
3796 struct perf_event_context *ctx, *clone_ctx = NULL;
3797 enum event_type_t event_type = 0;
3798 struct perf_cpu_context *cpuctx;
3799 struct perf_event *event;
3800 unsigned long flags;
3803 local_irq_save(flags);
3804 ctx = current->perf_event_ctxp[ctxn];
3805 if (!ctx || !ctx->nr_events)
3808 cpuctx = __get_cpu_context(ctx);
3809 perf_ctx_lock(cpuctx, ctx);
3810 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3811 list_for_each_entry(event, &ctx->event_list, event_entry) {
3812 enabled |= event_enable_on_exec(event, ctx);
3813 event_type |= get_event_type(event);
3817 * Unclone and reschedule this context if we enabled any event.
3820 clone_ctx = unclone_ctx(ctx);
3821 ctx_resched(cpuctx, ctx, event_type);
3823 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3825 perf_ctx_unlock(cpuctx, ctx);
3828 local_irq_restore(flags);
3834 struct perf_read_data {
3835 struct perf_event *event;
3840 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3842 u16 local_pkg, event_pkg;
3844 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3845 int local_cpu = smp_processor_id();
3847 event_pkg = topology_physical_package_id(event_cpu);
3848 local_pkg = topology_physical_package_id(local_cpu);
3850 if (event_pkg == local_pkg)
3858 * Cross CPU call to read the hardware event
3860 static void __perf_event_read(void *info)
3862 struct perf_read_data *data = info;
3863 struct perf_event *sub, *event = data->event;
3864 struct perf_event_context *ctx = event->ctx;
3865 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3866 struct pmu *pmu = event->pmu;
3869 * If this is a task context, we need to check whether it is
3870 * the current task context of this cpu. If not it has been
3871 * scheduled out before the smp call arrived. In that case
3872 * event->count would have been updated to a recent sample
3873 * when the event was scheduled out.
3875 if (ctx->task && cpuctx->task_ctx != ctx)
3878 raw_spin_lock(&ctx->lock);
3879 if (ctx->is_active & EVENT_TIME) {
3880 update_context_time(ctx);
3881 update_cgrp_time_from_event(event);
3884 perf_event_update_time(event);
3886 perf_event_update_sibling_time(event);
3888 if (event->state != PERF_EVENT_STATE_ACTIVE)
3897 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3901 for_each_sibling_event(sub, event) {
3902 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3904 * Use sibling's PMU rather than @event's since
3905 * sibling could be on different (eg: software) PMU.
3907 sub->pmu->read(sub);
3911 data->ret = pmu->commit_txn(pmu);
3914 raw_spin_unlock(&ctx->lock);
3917 static inline u64 perf_event_count(struct perf_event *event)
3919 return local64_read(&event->count) + atomic64_read(&event->child_count);
3923 * NMI-safe method to read a local event, that is an event that
3925 * - either for the current task, or for this CPU
3926 * - does not have inherit set, for inherited task events
3927 * will not be local and we cannot read them atomically
3928 * - must not have a pmu::count method
3930 int perf_event_read_local(struct perf_event *event, u64 *value,
3931 u64 *enabled, u64 *running)
3933 unsigned long flags;
3937 * Disabling interrupts avoids all counter scheduling (context
3938 * switches, timer based rotation and IPIs).
3940 local_irq_save(flags);
3943 * It must not be an event with inherit set, we cannot read
3944 * all child counters from atomic context.
3946 if (event->attr.inherit) {
3951 /* If this is a per-task event, it must be for current */
3952 if ((event->attach_state & PERF_ATTACH_TASK) &&
3953 event->hw.target != current) {
3958 /* If this is a per-CPU event, it must be for this CPU */
3959 if (!(event->attach_state & PERF_ATTACH_TASK) &&
3960 event->cpu != smp_processor_id()) {
3965 /* If this is a pinned event it must be running on this CPU */
3966 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
3972 * If the event is currently on this CPU, its either a per-task event,
3973 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3976 if (event->oncpu == smp_processor_id())
3977 event->pmu->read(event);
3979 *value = local64_read(&event->count);
3980 if (enabled || running) {
3981 u64 now = event->shadow_ctx_time + perf_clock();
3982 u64 __enabled, __running;
3984 __perf_update_times(event, now, &__enabled, &__running);
3986 *enabled = __enabled;
3988 *running = __running;
3991 local_irq_restore(flags);
3996 static int perf_event_read(struct perf_event *event, bool group)
3998 enum perf_event_state state = READ_ONCE(event->state);
3999 int event_cpu, ret = 0;
4002 * If event is enabled and currently active on a CPU, update the
4003 * value in the event structure:
4006 if (state == PERF_EVENT_STATE_ACTIVE) {
4007 struct perf_read_data data;
4010 * Orders the ->state and ->oncpu loads such that if we see
4011 * ACTIVE we must also see the right ->oncpu.
4013 * Matches the smp_wmb() from event_sched_in().
4017 event_cpu = READ_ONCE(event->oncpu);
4018 if ((unsigned)event_cpu >= nr_cpu_ids)
4021 data = (struct perf_read_data){
4028 event_cpu = __perf_event_read_cpu(event, event_cpu);
4031 * Purposely ignore the smp_call_function_single() return
4034 * If event_cpu isn't a valid CPU it means the event got
4035 * scheduled out and that will have updated the event count.
4037 * Therefore, either way, we'll have an up-to-date event count
4040 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4044 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4045 struct perf_event_context *ctx = event->ctx;
4046 unsigned long flags;
4048 raw_spin_lock_irqsave(&ctx->lock, flags);
4049 state = event->state;
4050 if (state != PERF_EVENT_STATE_INACTIVE) {
4051 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4056 * May read while context is not active (e.g., thread is
4057 * blocked), in that case we cannot update context time
4059 if (ctx->is_active & EVENT_TIME) {
4060 update_context_time(ctx);
4061 update_cgrp_time_from_event(event);
4064 perf_event_update_time(event);
4066 perf_event_update_sibling_time(event);
4067 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4074 * Initialize the perf_event context in a task_struct:
4076 static void __perf_event_init_context(struct perf_event_context *ctx)
4078 raw_spin_lock_init(&ctx->lock);
4079 mutex_init(&ctx->mutex);
4080 INIT_LIST_HEAD(&ctx->active_ctx_list);
4081 perf_event_groups_init(&ctx->pinned_groups);
4082 perf_event_groups_init(&ctx->flexible_groups);
4083 INIT_LIST_HEAD(&ctx->event_list);
4084 INIT_LIST_HEAD(&ctx->pinned_active);
4085 INIT_LIST_HEAD(&ctx->flexible_active);
4086 atomic_set(&ctx->refcount, 1);
4089 static struct perf_event_context *
4090 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4092 struct perf_event_context *ctx;
4094 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4098 __perf_event_init_context(ctx);
4101 get_task_struct(task);
4108 static struct task_struct *
4109 find_lively_task_by_vpid(pid_t vpid)
4111 struct task_struct *task;
4117 task = find_task_by_vpid(vpid);
4119 get_task_struct(task);
4123 return ERR_PTR(-ESRCH);
4129 * Returns a matching context with refcount and pincount.
4131 static struct perf_event_context *
4132 find_get_context(struct pmu *pmu, struct task_struct *task,
4133 struct perf_event *event)
4135 struct perf_event_context *ctx, *clone_ctx = NULL;
4136 struct perf_cpu_context *cpuctx;
4137 void *task_ctx_data = NULL;
4138 unsigned long flags;
4140 int cpu = event->cpu;
4143 /* Must be root to operate on a CPU event: */
4144 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
4145 return ERR_PTR(-EACCES);
4147 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4156 ctxn = pmu->task_ctx_nr;
4160 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4161 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4162 if (!task_ctx_data) {
4169 ctx = perf_lock_task_context(task, ctxn, &flags);
4171 clone_ctx = unclone_ctx(ctx);
4174 if (task_ctx_data && !ctx->task_ctx_data) {
4175 ctx->task_ctx_data = task_ctx_data;
4176 task_ctx_data = NULL;
4178 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4183 ctx = alloc_perf_context(pmu, task);
4188 if (task_ctx_data) {
4189 ctx->task_ctx_data = task_ctx_data;
4190 task_ctx_data = NULL;
4194 mutex_lock(&task->perf_event_mutex);
4196 * If it has already passed perf_event_exit_task().
4197 * we must see PF_EXITING, it takes this mutex too.
4199 if (task->flags & PF_EXITING)
4201 else if (task->perf_event_ctxp[ctxn])
4206 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4208 mutex_unlock(&task->perf_event_mutex);
4210 if (unlikely(err)) {
4219 kfree(task_ctx_data);
4223 kfree(task_ctx_data);
4224 return ERR_PTR(err);
4227 static void perf_event_free_filter(struct perf_event *event);
4228 static void perf_event_free_bpf_prog(struct perf_event *event);
4230 static void free_event_rcu(struct rcu_head *head)
4232 struct perf_event *event;
4234 event = container_of(head, struct perf_event, rcu_head);
4236 put_pid_ns(event->ns);
4237 perf_event_free_filter(event);
4241 static void ring_buffer_attach(struct perf_event *event,
4242 struct ring_buffer *rb);
4244 static void detach_sb_event(struct perf_event *event)
4246 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4248 raw_spin_lock(&pel->lock);
4249 list_del_rcu(&event->sb_list);
4250 raw_spin_unlock(&pel->lock);
4253 static bool is_sb_event(struct perf_event *event)
4255 struct perf_event_attr *attr = &event->attr;
4260 if (event->attach_state & PERF_ATTACH_TASK)
4263 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4264 attr->comm || attr->comm_exec ||
4266 attr->context_switch)
4271 static void unaccount_pmu_sb_event(struct perf_event *event)
4273 if (is_sb_event(event))
4274 detach_sb_event(event);
4277 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4282 if (is_cgroup_event(event))
4283 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4286 #ifdef CONFIG_NO_HZ_FULL
4287 static DEFINE_SPINLOCK(nr_freq_lock);
4290 static void unaccount_freq_event_nohz(void)
4292 #ifdef CONFIG_NO_HZ_FULL
4293 spin_lock(&nr_freq_lock);
4294 if (atomic_dec_and_test(&nr_freq_events))
4295 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4296 spin_unlock(&nr_freq_lock);
4300 static void unaccount_freq_event(void)
4302 if (tick_nohz_full_enabled())
4303 unaccount_freq_event_nohz();
4305 atomic_dec(&nr_freq_events);
4308 static void unaccount_event(struct perf_event *event)
4315 if (event->attach_state & PERF_ATTACH_TASK)
4317 if (event->attr.mmap || event->attr.mmap_data)
4318 atomic_dec(&nr_mmap_events);
4319 if (event->attr.comm)
4320 atomic_dec(&nr_comm_events);
4321 if (event->attr.namespaces)
4322 atomic_dec(&nr_namespaces_events);
4323 if (event->attr.task)
4324 atomic_dec(&nr_task_events);
4325 if (event->attr.freq)
4326 unaccount_freq_event();
4327 if (event->attr.context_switch) {
4329 atomic_dec(&nr_switch_events);
4331 if (is_cgroup_event(event))
4333 if (has_branch_stack(event))
4337 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4338 schedule_delayed_work(&perf_sched_work, HZ);
4341 unaccount_event_cpu(event, event->cpu);
4343 unaccount_pmu_sb_event(event);
4346 static void perf_sched_delayed(struct work_struct *work)
4348 mutex_lock(&perf_sched_mutex);
4349 if (atomic_dec_and_test(&perf_sched_count))
4350 static_branch_disable(&perf_sched_events);
4351 mutex_unlock(&perf_sched_mutex);
4355 * The following implement mutual exclusion of events on "exclusive" pmus
4356 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4357 * at a time, so we disallow creating events that might conflict, namely:
4359 * 1) cpu-wide events in the presence of per-task events,
4360 * 2) per-task events in the presence of cpu-wide events,
4361 * 3) two matching events on the same context.
4363 * The former two cases are handled in the allocation path (perf_event_alloc(),
4364 * _free_event()), the latter -- before the first perf_install_in_context().
4366 static int exclusive_event_init(struct perf_event *event)
4368 struct pmu *pmu = event->pmu;
4370 if (!is_exclusive_pmu(pmu))
4374 * Prevent co-existence of per-task and cpu-wide events on the
4375 * same exclusive pmu.
4377 * Negative pmu::exclusive_cnt means there are cpu-wide
4378 * events on this "exclusive" pmu, positive means there are
4381 * Since this is called in perf_event_alloc() path, event::ctx
4382 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4383 * to mean "per-task event", because unlike other attach states it
4384 * never gets cleared.
4386 if (event->attach_state & PERF_ATTACH_TASK) {
4387 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4390 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4397 static void exclusive_event_destroy(struct perf_event *event)
4399 struct pmu *pmu = event->pmu;
4401 if (!is_exclusive_pmu(pmu))
4404 /* see comment in exclusive_event_init() */
4405 if (event->attach_state & PERF_ATTACH_TASK)
4406 atomic_dec(&pmu->exclusive_cnt);
4408 atomic_inc(&pmu->exclusive_cnt);
4411 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4413 if ((e1->pmu == e2->pmu) &&
4414 (e1->cpu == e2->cpu ||
4421 static bool exclusive_event_installable(struct perf_event *event,
4422 struct perf_event_context *ctx)
4424 struct perf_event *iter_event;
4425 struct pmu *pmu = event->pmu;
4427 lockdep_assert_held(&ctx->mutex);
4429 if (!is_exclusive_pmu(pmu))
4432 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4433 if (exclusive_event_match(iter_event, event))
4440 static void perf_addr_filters_splice(struct perf_event *event,
4441 struct list_head *head);
4443 static void _free_event(struct perf_event *event)
4445 irq_work_sync(&event->pending);
4447 unaccount_event(event);
4451 * Can happen when we close an event with re-directed output.
4453 * Since we have a 0 refcount, perf_mmap_close() will skip
4454 * over us; possibly making our ring_buffer_put() the last.
4456 mutex_lock(&event->mmap_mutex);
4457 ring_buffer_attach(event, NULL);
4458 mutex_unlock(&event->mmap_mutex);
4461 if (is_cgroup_event(event))
4462 perf_detach_cgroup(event);
4464 if (!event->parent) {
4465 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4466 put_callchain_buffers();
4469 perf_event_free_bpf_prog(event);
4470 perf_addr_filters_splice(event, NULL);
4471 kfree(event->addr_filter_ranges);
4474 event->destroy(event);
4477 * Must be after ->destroy(), due to uprobe_perf_close() using
4480 if (event->hw.target)
4481 put_task_struct(event->hw.target);
4484 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4485 * all task references must be cleaned up.
4488 put_ctx(event->ctx);
4490 exclusive_event_destroy(event);
4491 module_put(event->pmu->module);
4493 call_rcu(&event->rcu_head, free_event_rcu);
4497 * Used to free events which have a known refcount of 1, such as in error paths
4498 * where the event isn't exposed yet and inherited events.
4500 static void free_event(struct perf_event *event)
4502 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4503 "unexpected event refcount: %ld; ptr=%p\n",
4504 atomic_long_read(&event->refcount), event)) {
4505 /* leak to avoid use-after-free */
4513 * Remove user event from the owner task.
4515 static void perf_remove_from_owner(struct perf_event *event)
4517 struct task_struct *owner;
4521 * Matches the smp_store_release() in perf_event_exit_task(). If we
4522 * observe !owner it means the list deletion is complete and we can
4523 * indeed free this event, otherwise we need to serialize on
4524 * owner->perf_event_mutex.
4526 owner = READ_ONCE(event->owner);
4529 * Since delayed_put_task_struct() also drops the last
4530 * task reference we can safely take a new reference
4531 * while holding the rcu_read_lock().
4533 get_task_struct(owner);
4539 * If we're here through perf_event_exit_task() we're already
4540 * holding ctx->mutex which would be an inversion wrt. the
4541 * normal lock order.
4543 * However we can safely take this lock because its the child
4546 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4549 * We have to re-check the event->owner field, if it is cleared
4550 * we raced with perf_event_exit_task(), acquiring the mutex
4551 * ensured they're done, and we can proceed with freeing the
4555 list_del_init(&event->owner_entry);
4556 smp_store_release(&event->owner, NULL);
4558 mutex_unlock(&owner->perf_event_mutex);
4559 put_task_struct(owner);
4563 static void put_event(struct perf_event *event)
4565 if (!atomic_long_dec_and_test(&event->refcount))
4572 * Kill an event dead; while event:refcount will preserve the event
4573 * object, it will not preserve its functionality. Once the last 'user'
4574 * gives up the object, we'll destroy the thing.
4576 int perf_event_release_kernel(struct perf_event *event)
4578 struct perf_event_context *ctx = event->ctx;
4579 struct perf_event *child, *tmp;
4580 LIST_HEAD(free_list);
4583 * If we got here through err_file: fput(event_file); we will not have
4584 * attached to a context yet.
4587 WARN_ON_ONCE(event->attach_state &
4588 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4592 if (!is_kernel_event(event))
4593 perf_remove_from_owner(event);
4595 ctx = perf_event_ctx_lock(event);
4596 WARN_ON_ONCE(ctx->parent_ctx);
4597 perf_remove_from_context(event, DETACH_GROUP);
4599 raw_spin_lock_irq(&ctx->lock);
4601 * Mark this event as STATE_DEAD, there is no external reference to it
4604 * Anybody acquiring event->child_mutex after the below loop _must_
4605 * also see this, most importantly inherit_event() which will avoid
4606 * placing more children on the list.
4608 * Thus this guarantees that we will in fact observe and kill _ALL_
4611 event->state = PERF_EVENT_STATE_DEAD;
4612 raw_spin_unlock_irq(&ctx->lock);
4614 perf_event_ctx_unlock(event, ctx);
4617 mutex_lock(&event->child_mutex);
4618 list_for_each_entry(child, &event->child_list, child_list) {
4621 * Cannot change, child events are not migrated, see the
4622 * comment with perf_event_ctx_lock_nested().
4624 ctx = READ_ONCE(child->ctx);
4626 * Since child_mutex nests inside ctx::mutex, we must jump
4627 * through hoops. We start by grabbing a reference on the ctx.
4629 * Since the event cannot get freed while we hold the
4630 * child_mutex, the context must also exist and have a !0
4636 * Now that we have a ctx ref, we can drop child_mutex, and
4637 * acquire ctx::mutex without fear of it going away. Then we
4638 * can re-acquire child_mutex.
4640 mutex_unlock(&event->child_mutex);
4641 mutex_lock(&ctx->mutex);
4642 mutex_lock(&event->child_mutex);
4645 * Now that we hold ctx::mutex and child_mutex, revalidate our
4646 * state, if child is still the first entry, it didn't get freed
4647 * and we can continue doing so.
4649 tmp = list_first_entry_or_null(&event->child_list,
4650 struct perf_event, child_list);
4652 perf_remove_from_context(child, DETACH_GROUP);
4653 list_move(&child->child_list, &free_list);
4655 * This matches the refcount bump in inherit_event();
4656 * this can't be the last reference.
4661 mutex_unlock(&event->child_mutex);
4662 mutex_unlock(&ctx->mutex);
4666 mutex_unlock(&event->child_mutex);
4668 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4669 void *var = &child->ctx->refcount;
4671 list_del(&child->child_list);
4675 * Wake any perf_event_free_task() waiting for this event to be
4678 smp_mb(); /* pairs with wait_var_event() */
4683 put_event(event); /* Must be the 'last' reference */
4686 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4689 * Called when the last reference to the file is gone.
4691 static int perf_release(struct inode *inode, struct file *file)
4693 perf_event_release_kernel(file->private_data);
4697 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4699 struct perf_event *child;
4705 mutex_lock(&event->child_mutex);
4707 (void)perf_event_read(event, false);
4708 total += perf_event_count(event);
4710 *enabled += event->total_time_enabled +
4711 atomic64_read(&event->child_total_time_enabled);
4712 *running += event->total_time_running +
4713 atomic64_read(&event->child_total_time_running);
4715 list_for_each_entry(child, &event->child_list, child_list) {
4716 (void)perf_event_read(child, false);
4717 total += perf_event_count(child);
4718 *enabled += child->total_time_enabled;
4719 *running += child->total_time_running;
4721 mutex_unlock(&event->child_mutex);
4726 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4728 struct perf_event_context *ctx;
4731 ctx = perf_event_ctx_lock(event);
4732 count = __perf_event_read_value(event, enabled, running);
4733 perf_event_ctx_unlock(event, ctx);
4737 EXPORT_SYMBOL_GPL(perf_event_read_value);
4739 static int __perf_read_group_add(struct perf_event *leader,
4740 u64 read_format, u64 *values)
4742 struct perf_event_context *ctx = leader->ctx;
4743 struct perf_event *sub;
4744 unsigned long flags;
4745 int n = 1; /* skip @nr */
4748 ret = perf_event_read(leader, true);
4752 raw_spin_lock_irqsave(&ctx->lock, flags);
4755 * Since we co-schedule groups, {enabled,running} times of siblings
4756 * will be identical to those of the leader, so we only publish one
4759 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4760 values[n++] += leader->total_time_enabled +
4761 atomic64_read(&leader->child_total_time_enabled);
4764 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4765 values[n++] += leader->total_time_running +
4766 atomic64_read(&leader->child_total_time_running);
4770 * Write {count,id} tuples for every sibling.
4772 values[n++] += perf_event_count(leader);
4773 if (read_format & PERF_FORMAT_ID)
4774 values[n++] = primary_event_id(leader);
4776 for_each_sibling_event(sub, leader) {
4777 values[n++] += perf_event_count(sub);
4778 if (read_format & PERF_FORMAT_ID)
4779 values[n++] = primary_event_id(sub);
4782 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4786 static int perf_read_group(struct perf_event *event,
4787 u64 read_format, char __user *buf)
4789 struct perf_event *leader = event->group_leader, *child;
4790 struct perf_event_context *ctx = leader->ctx;
4794 lockdep_assert_held(&ctx->mutex);
4796 values = kzalloc(event->read_size, GFP_KERNEL);
4800 values[0] = 1 + leader->nr_siblings;
4803 * By locking the child_mutex of the leader we effectively
4804 * lock the child list of all siblings.. XXX explain how.
4806 mutex_lock(&leader->child_mutex);
4808 ret = __perf_read_group_add(leader, read_format, values);
4812 list_for_each_entry(child, &leader->child_list, child_list) {
4813 ret = __perf_read_group_add(child, read_format, values);
4818 mutex_unlock(&leader->child_mutex);
4820 ret = event->read_size;
4821 if (copy_to_user(buf, values, event->read_size))
4826 mutex_unlock(&leader->child_mutex);
4832 static int perf_read_one(struct perf_event *event,
4833 u64 read_format, char __user *buf)
4835 u64 enabled, running;
4839 values[n++] = __perf_event_read_value(event, &enabled, &running);
4840 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4841 values[n++] = enabled;
4842 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4843 values[n++] = running;
4844 if (read_format & PERF_FORMAT_ID)
4845 values[n++] = primary_event_id(event);
4847 if (copy_to_user(buf, values, n * sizeof(u64)))
4850 return n * sizeof(u64);
4853 static bool is_event_hup(struct perf_event *event)
4857 if (event->state > PERF_EVENT_STATE_EXIT)
4860 mutex_lock(&event->child_mutex);
4861 no_children = list_empty(&event->child_list);
4862 mutex_unlock(&event->child_mutex);
4867 * Read the performance event - simple non blocking version for now
4870 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4872 u64 read_format = event->attr.read_format;
4876 * Return end-of-file for a read on an event that is in
4877 * error state (i.e. because it was pinned but it couldn't be
4878 * scheduled on to the CPU at some point).
4880 if (event->state == PERF_EVENT_STATE_ERROR)
4883 if (count < event->read_size)
4886 WARN_ON_ONCE(event->ctx->parent_ctx);
4887 if (read_format & PERF_FORMAT_GROUP)
4888 ret = perf_read_group(event, read_format, buf);
4890 ret = perf_read_one(event, read_format, buf);
4896 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4898 struct perf_event *event = file->private_data;
4899 struct perf_event_context *ctx;
4902 ctx = perf_event_ctx_lock(event);
4903 ret = __perf_read(event, buf, count);
4904 perf_event_ctx_unlock(event, ctx);
4909 static __poll_t perf_poll(struct file *file, poll_table *wait)
4911 struct perf_event *event = file->private_data;
4912 struct ring_buffer *rb;
4913 __poll_t events = EPOLLHUP;
4915 poll_wait(file, &event->waitq, wait);
4917 if (is_event_hup(event))
4921 * Pin the event->rb by taking event->mmap_mutex; otherwise
4922 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4924 mutex_lock(&event->mmap_mutex);
4927 events = atomic_xchg(&rb->poll, 0);
4928 mutex_unlock(&event->mmap_mutex);
4932 static void _perf_event_reset(struct perf_event *event)
4934 (void)perf_event_read(event, false);
4935 local64_set(&event->count, 0);
4936 perf_event_update_userpage(event);
4940 * Holding the top-level event's child_mutex means that any
4941 * descendant process that has inherited this event will block
4942 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4943 * task existence requirements of perf_event_enable/disable.
4945 static void perf_event_for_each_child(struct perf_event *event,
4946 void (*func)(struct perf_event *))
4948 struct perf_event *child;
4950 WARN_ON_ONCE(event->ctx->parent_ctx);
4952 mutex_lock(&event->child_mutex);
4954 list_for_each_entry(child, &event->child_list, child_list)
4956 mutex_unlock(&event->child_mutex);
4959 static void perf_event_for_each(struct perf_event *event,
4960 void (*func)(struct perf_event *))
4962 struct perf_event_context *ctx = event->ctx;
4963 struct perf_event *sibling;
4965 lockdep_assert_held(&ctx->mutex);
4967 event = event->group_leader;
4969 perf_event_for_each_child(event, func);
4970 for_each_sibling_event(sibling, event)
4971 perf_event_for_each_child(sibling, func);
4974 static void __perf_event_period(struct perf_event *event,
4975 struct perf_cpu_context *cpuctx,
4976 struct perf_event_context *ctx,
4979 u64 value = *((u64 *)info);
4982 if (event->attr.freq) {
4983 event->attr.sample_freq = value;
4985 event->attr.sample_period = value;
4986 event->hw.sample_period = value;
4989 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4991 perf_pmu_disable(ctx->pmu);
4993 * We could be throttled; unthrottle now to avoid the tick
4994 * trying to unthrottle while we already re-started the event.
4996 if (event->hw.interrupts == MAX_INTERRUPTS) {
4997 event->hw.interrupts = 0;
4998 perf_log_throttle(event, 1);
5000 event->pmu->stop(event, PERF_EF_UPDATE);
5003 local64_set(&event->hw.period_left, 0);
5006 event->pmu->start(event, PERF_EF_RELOAD);
5007 perf_pmu_enable(ctx->pmu);
5011 static int perf_event_check_period(struct perf_event *event, u64 value)
5013 return event->pmu->check_period(event, value);
5016 static int perf_event_period(struct perf_event *event, u64 __user *arg)
5020 if (!is_sampling_event(event))
5023 if (copy_from_user(&value, arg, sizeof(value)))
5029 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5032 if (perf_event_check_period(event, value))
5035 if (!event->attr.freq && (value & (1ULL << 63)))
5038 event_function_call(event, __perf_event_period, &value);
5043 static const struct file_operations perf_fops;
5045 static inline int perf_fget_light(int fd, struct fd *p)
5047 struct fd f = fdget(fd);
5051 if (f.file->f_op != &perf_fops) {
5059 static int perf_event_set_output(struct perf_event *event,
5060 struct perf_event *output_event);
5061 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5062 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5063 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5064 struct perf_event_attr *attr);
5066 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5068 void (*func)(struct perf_event *);
5072 case PERF_EVENT_IOC_ENABLE:
5073 func = _perf_event_enable;
5075 case PERF_EVENT_IOC_DISABLE:
5076 func = _perf_event_disable;
5078 case PERF_EVENT_IOC_RESET:
5079 func = _perf_event_reset;
5082 case PERF_EVENT_IOC_REFRESH:
5083 return _perf_event_refresh(event, arg);
5085 case PERF_EVENT_IOC_PERIOD:
5086 return perf_event_period(event, (u64 __user *)arg);
5088 case PERF_EVENT_IOC_ID:
5090 u64 id = primary_event_id(event);
5092 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5097 case PERF_EVENT_IOC_SET_OUTPUT:
5101 struct perf_event *output_event;
5103 ret = perf_fget_light(arg, &output);
5106 output_event = output.file->private_data;
5107 ret = perf_event_set_output(event, output_event);
5110 ret = perf_event_set_output(event, NULL);
5115 case PERF_EVENT_IOC_SET_FILTER:
5116 return perf_event_set_filter(event, (void __user *)arg);
5118 case PERF_EVENT_IOC_SET_BPF:
5119 return perf_event_set_bpf_prog(event, arg);
5121 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5122 struct ring_buffer *rb;
5125 rb = rcu_dereference(event->rb);
5126 if (!rb || !rb->nr_pages) {
5130 rb_toggle_paused(rb, !!arg);
5135 case PERF_EVENT_IOC_QUERY_BPF:
5136 return perf_event_query_prog_array(event, (void __user *)arg);
5138 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5139 struct perf_event_attr new_attr;
5140 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5146 return perf_event_modify_attr(event, &new_attr);
5152 if (flags & PERF_IOC_FLAG_GROUP)
5153 perf_event_for_each(event, func);
5155 perf_event_for_each_child(event, func);
5160 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5162 struct perf_event *event = file->private_data;
5163 struct perf_event_context *ctx;
5166 ctx = perf_event_ctx_lock(event);
5167 ret = _perf_ioctl(event, cmd, arg);
5168 perf_event_ctx_unlock(event, ctx);
5173 #ifdef CONFIG_COMPAT
5174 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5177 switch (_IOC_NR(cmd)) {
5178 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5179 case _IOC_NR(PERF_EVENT_IOC_ID):
5180 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5181 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5182 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5183 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5184 cmd &= ~IOCSIZE_MASK;
5185 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5189 return perf_ioctl(file, cmd, arg);
5192 # define perf_compat_ioctl NULL
5195 int perf_event_task_enable(void)
5197 struct perf_event_context *ctx;
5198 struct perf_event *event;
5200 mutex_lock(¤t->perf_event_mutex);
5201 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5202 ctx = perf_event_ctx_lock(event);
5203 perf_event_for_each_child(event, _perf_event_enable);
5204 perf_event_ctx_unlock(event, ctx);
5206 mutex_unlock(¤t->perf_event_mutex);
5211 int perf_event_task_disable(void)
5213 struct perf_event_context *ctx;
5214 struct perf_event *event;
5216 mutex_lock(¤t->perf_event_mutex);
5217 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5218 ctx = perf_event_ctx_lock(event);
5219 perf_event_for_each_child(event, _perf_event_disable);
5220 perf_event_ctx_unlock(event, ctx);
5222 mutex_unlock(¤t->perf_event_mutex);
5227 static int perf_event_index(struct perf_event *event)
5229 if (event->hw.state & PERF_HES_STOPPED)
5232 if (event->state != PERF_EVENT_STATE_ACTIVE)
5235 return event->pmu->event_idx(event);
5238 static void calc_timer_values(struct perf_event *event,
5245 *now = perf_clock();
5246 ctx_time = event->shadow_ctx_time + *now;
5247 __perf_update_times(event, ctx_time, enabled, running);
5250 static void perf_event_init_userpage(struct perf_event *event)
5252 struct perf_event_mmap_page *userpg;
5253 struct ring_buffer *rb;
5256 rb = rcu_dereference(event->rb);
5260 userpg = rb->user_page;
5262 /* Allow new userspace to detect that bit 0 is deprecated */
5263 userpg->cap_bit0_is_deprecated = 1;
5264 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5265 userpg->data_offset = PAGE_SIZE;
5266 userpg->data_size = perf_data_size(rb);
5272 void __weak arch_perf_update_userpage(
5273 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5278 * Callers need to ensure there can be no nesting of this function, otherwise
5279 * the seqlock logic goes bad. We can not serialize this because the arch
5280 * code calls this from NMI context.
5282 void perf_event_update_userpage(struct perf_event *event)
5284 struct perf_event_mmap_page *userpg;
5285 struct ring_buffer *rb;
5286 u64 enabled, running, now;
5289 rb = rcu_dereference(event->rb);
5294 * compute total_time_enabled, total_time_running
5295 * based on snapshot values taken when the event
5296 * was last scheduled in.
5298 * we cannot simply called update_context_time()
5299 * because of locking issue as we can be called in
5302 calc_timer_values(event, &now, &enabled, &running);
5304 userpg = rb->user_page;
5306 * Disable preemption to guarantee consistent time stamps are stored to
5312 userpg->index = perf_event_index(event);
5313 userpg->offset = perf_event_count(event);
5315 userpg->offset -= local64_read(&event->hw.prev_count);
5317 userpg->time_enabled = enabled +
5318 atomic64_read(&event->child_total_time_enabled);
5320 userpg->time_running = running +
5321 atomic64_read(&event->child_total_time_running);
5323 arch_perf_update_userpage(event, userpg, now);
5331 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5333 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5335 struct perf_event *event = vmf->vma->vm_file->private_data;
5336 struct ring_buffer *rb;
5337 vm_fault_t ret = VM_FAULT_SIGBUS;
5339 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5340 if (vmf->pgoff == 0)
5346 rb = rcu_dereference(event->rb);
5350 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5353 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5357 get_page(vmf->page);
5358 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5359 vmf->page->index = vmf->pgoff;
5368 static void ring_buffer_attach(struct perf_event *event,
5369 struct ring_buffer *rb)
5371 struct ring_buffer *old_rb = NULL;
5372 unsigned long flags;
5376 * Should be impossible, we set this when removing
5377 * event->rb_entry and wait/clear when adding event->rb_entry.
5379 WARN_ON_ONCE(event->rcu_pending);
5382 spin_lock_irqsave(&old_rb->event_lock, flags);
5383 list_del_rcu(&event->rb_entry);
5384 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5386 event->rcu_batches = get_state_synchronize_rcu();
5387 event->rcu_pending = 1;
5391 if (event->rcu_pending) {
5392 cond_synchronize_rcu(event->rcu_batches);
5393 event->rcu_pending = 0;
5396 spin_lock_irqsave(&rb->event_lock, flags);
5397 list_add_rcu(&event->rb_entry, &rb->event_list);
5398 spin_unlock_irqrestore(&rb->event_lock, flags);
5402 * Avoid racing with perf_mmap_close(AUX): stop the event
5403 * before swizzling the event::rb pointer; if it's getting
5404 * unmapped, its aux_mmap_count will be 0 and it won't
5405 * restart. See the comment in __perf_pmu_output_stop().
5407 * Data will inevitably be lost when set_output is done in
5408 * mid-air, but then again, whoever does it like this is
5409 * not in for the data anyway.
5412 perf_event_stop(event, 0);
5414 rcu_assign_pointer(event->rb, rb);
5417 ring_buffer_put(old_rb);
5419 * Since we detached before setting the new rb, so that we
5420 * could attach the new rb, we could have missed a wakeup.
5423 wake_up_all(&event->waitq);
5427 static void ring_buffer_wakeup(struct perf_event *event)
5429 struct ring_buffer *rb;
5432 rb = rcu_dereference(event->rb);
5434 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5435 wake_up_all(&event->waitq);
5440 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5442 struct ring_buffer *rb;
5445 rb = rcu_dereference(event->rb);
5447 if (!atomic_inc_not_zero(&rb->refcount))
5455 void ring_buffer_put(struct ring_buffer *rb)
5457 if (!atomic_dec_and_test(&rb->refcount))
5460 WARN_ON_ONCE(!list_empty(&rb->event_list));
5462 call_rcu(&rb->rcu_head, rb_free_rcu);
5465 static void perf_mmap_open(struct vm_area_struct *vma)
5467 struct perf_event *event = vma->vm_file->private_data;
5469 atomic_inc(&event->mmap_count);
5470 atomic_inc(&event->rb->mmap_count);
5473 atomic_inc(&event->rb->aux_mmap_count);
5475 if (event->pmu->event_mapped)
5476 event->pmu->event_mapped(event, vma->vm_mm);
5479 static void perf_pmu_output_stop(struct perf_event *event);
5482 * A buffer can be mmap()ed multiple times; either directly through the same
5483 * event, or through other events by use of perf_event_set_output().
5485 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5486 * the buffer here, where we still have a VM context. This means we need
5487 * to detach all events redirecting to us.
5489 static void perf_mmap_close(struct vm_area_struct *vma)
5491 struct perf_event *event = vma->vm_file->private_data;
5492 struct ring_buffer *rb = ring_buffer_get(event);
5493 struct user_struct *mmap_user = rb->mmap_user;
5494 int mmap_locked = rb->mmap_locked;
5495 unsigned long size = perf_data_size(rb);
5496 bool detach_rest = false;
5498 if (event->pmu->event_unmapped)
5499 event->pmu->event_unmapped(event, vma->vm_mm);
5502 * rb->aux_mmap_count will always drop before rb->mmap_count and
5503 * event->mmap_count, so it is ok to use event->mmap_mutex to
5504 * serialize with perf_mmap here.
5506 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5507 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5509 * Stop all AUX events that are writing to this buffer,
5510 * so that we can free its AUX pages and corresponding PMU
5511 * data. Note that after rb::aux_mmap_count dropped to zero,
5512 * they won't start any more (see perf_aux_output_begin()).
5514 perf_pmu_output_stop(event);
5516 /* now it's safe to free the pages */
5517 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5518 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5520 /* this has to be the last one */
5522 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5524 mutex_unlock(&event->mmap_mutex);
5527 if (atomic_dec_and_test(&rb->mmap_count))
5530 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5533 ring_buffer_attach(event, NULL);
5534 mutex_unlock(&event->mmap_mutex);
5536 /* If there's still other mmap()s of this buffer, we're done. */
5541 * No other mmap()s, detach from all other events that might redirect
5542 * into the now unreachable buffer. Somewhat complicated by the
5543 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5547 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5548 if (!atomic_long_inc_not_zero(&event->refcount)) {
5550 * This event is en-route to free_event() which will
5551 * detach it and remove it from the list.
5557 mutex_lock(&event->mmap_mutex);
5559 * Check we didn't race with perf_event_set_output() which can
5560 * swizzle the rb from under us while we were waiting to
5561 * acquire mmap_mutex.
5563 * If we find a different rb; ignore this event, a next
5564 * iteration will no longer find it on the list. We have to
5565 * still restart the iteration to make sure we're not now
5566 * iterating the wrong list.
5568 if (event->rb == rb)
5569 ring_buffer_attach(event, NULL);
5571 mutex_unlock(&event->mmap_mutex);
5575 * Restart the iteration; either we're on the wrong list or
5576 * destroyed its integrity by doing a deletion.
5583 * It could be there's still a few 0-ref events on the list; they'll
5584 * get cleaned up by free_event() -- they'll also still have their
5585 * ref on the rb and will free it whenever they are done with it.
5587 * Aside from that, this buffer is 'fully' detached and unmapped,
5588 * undo the VM accounting.
5591 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5592 vma->vm_mm->pinned_vm -= mmap_locked;
5593 free_uid(mmap_user);
5596 ring_buffer_put(rb); /* could be last */
5599 static const struct vm_operations_struct perf_mmap_vmops = {
5600 .open = perf_mmap_open,
5601 .close = perf_mmap_close, /* non mergable */
5602 .fault = perf_mmap_fault,
5603 .page_mkwrite = perf_mmap_fault,
5606 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5608 struct perf_event *event = file->private_data;
5609 unsigned long user_locked, user_lock_limit;
5610 struct user_struct *user = current_user();
5611 unsigned long locked, lock_limit;
5612 struct ring_buffer *rb = NULL;
5613 unsigned long vma_size;
5614 unsigned long nr_pages;
5615 long user_extra = 0, extra = 0;
5616 int ret = 0, flags = 0;
5619 * Don't allow mmap() of inherited per-task counters. This would
5620 * create a performance issue due to all children writing to the
5623 if (event->cpu == -1 && event->attr.inherit)
5626 if (!(vma->vm_flags & VM_SHARED))
5629 vma_size = vma->vm_end - vma->vm_start;
5631 if (vma->vm_pgoff == 0) {
5632 nr_pages = (vma_size / PAGE_SIZE) - 1;
5635 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5636 * mapped, all subsequent mappings should have the same size
5637 * and offset. Must be above the normal perf buffer.
5639 u64 aux_offset, aux_size;
5644 nr_pages = vma_size / PAGE_SIZE;
5646 mutex_lock(&event->mmap_mutex);
5653 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5654 aux_size = READ_ONCE(rb->user_page->aux_size);
5656 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5659 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5662 /* already mapped with a different offset */
5663 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5666 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5669 /* already mapped with a different size */
5670 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5673 if (!is_power_of_2(nr_pages))
5676 if (!atomic_inc_not_zero(&rb->mmap_count))
5679 if (rb_has_aux(rb)) {
5680 atomic_inc(&rb->aux_mmap_count);
5685 atomic_set(&rb->aux_mmap_count, 1);
5686 user_extra = nr_pages;
5692 * If we have rb pages ensure they're a power-of-two number, so we
5693 * can do bitmasks instead of modulo.
5695 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5698 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5701 WARN_ON_ONCE(event->ctx->parent_ctx);
5703 mutex_lock(&event->mmap_mutex);
5705 if (event->rb->nr_pages != nr_pages) {
5710 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5712 * Raced against perf_mmap_close() through
5713 * perf_event_set_output(). Try again, hope for better
5716 mutex_unlock(&event->mmap_mutex);
5723 user_extra = nr_pages + 1;
5726 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5729 * Increase the limit linearly with more CPUs:
5731 user_lock_limit *= num_online_cpus();
5733 user_locked = atomic_long_read(&user->locked_vm);
5736 * sysctl_perf_event_mlock may have changed, so that
5737 * user->locked_vm > user_lock_limit
5739 if (user_locked > user_lock_limit)
5740 user_locked = user_lock_limit;
5741 user_locked += user_extra;
5743 if (user_locked > user_lock_limit)
5744 extra = user_locked - user_lock_limit;
5746 lock_limit = rlimit(RLIMIT_MEMLOCK);
5747 lock_limit >>= PAGE_SHIFT;
5748 locked = vma->vm_mm->pinned_vm + extra;
5750 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5751 !capable(CAP_IPC_LOCK)) {
5756 WARN_ON(!rb && event->rb);
5758 if (vma->vm_flags & VM_WRITE)
5759 flags |= RING_BUFFER_WRITABLE;
5762 rb = rb_alloc(nr_pages,
5763 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5771 atomic_set(&rb->mmap_count, 1);
5772 rb->mmap_user = get_current_user();
5773 rb->mmap_locked = extra;
5775 ring_buffer_attach(event, rb);
5777 perf_event_init_userpage(event);
5778 perf_event_update_userpage(event);
5780 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5781 event->attr.aux_watermark, flags);
5783 rb->aux_mmap_locked = extra;
5788 atomic_long_add(user_extra, &user->locked_vm);
5789 vma->vm_mm->pinned_vm += extra;
5791 atomic_inc(&event->mmap_count);
5793 atomic_dec(&rb->mmap_count);
5796 mutex_unlock(&event->mmap_mutex);
5799 * Since pinned accounting is per vm we cannot allow fork() to copy our
5802 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5803 vma->vm_ops = &perf_mmap_vmops;
5805 if (event->pmu->event_mapped)
5806 event->pmu->event_mapped(event, vma->vm_mm);
5811 static int perf_fasync(int fd, struct file *filp, int on)
5813 struct inode *inode = file_inode(filp);
5814 struct perf_event *event = filp->private_data;
5818 retval = fasync_helper(fd, filp, on, &event->fasync);
5819 inode_unlock(inode);
5827 static const struct file_operations perf_fops = {
5828 .llseek = no_llseek,
5829 .release = perf_release,
5832 .unlocked_ioctl = perf_ioctl,
5833 .compat_ioctl = perf_compat_ioctl,
5835 .fasync = perf_fasync,
5841 * If there's data, ensure we set the poll() state and publish everything
5842 * to user-space before waking everybody up.
5845 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5847 /* only the parent has fasync state */
5849 event = event->parent;
5850 return &event->fasync;
5853 void perf_event_wakeup(struct perf_event *event)
5855 ring_buffer_wakeup(event);
5857 if (event->pending_kill) {
5858 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5859 event->pending_kill = 0;
5863 static void perf_pending_event_disable(struct perf_event *event)
5865 int cpu = READ_ONCE(event->pending_disable);
5870 if (cpu == smp_processor_id()) {
5871 WRITE_ONCE(event->pending_disable, -1);
5872 perf_event_disable_local(event);
5879 * perf_event_disable_inatomic()
5880 * @pending_disable = CPU-A;
5884 * @pending_disable = -1;
5887 * perf_event_disable_inatomic()
5888 * @pending_disable = CPU-B;
5889 * irq_work_queue(); // FAILS
5892 * perf_pending_event()
5894 * But the event runs on CPU-B and wants disabling there.
5896 irq_work_queue_on(&event->pending, cpu);
5899 static void perf_pending_event(struct irq_work *entry)
5901 struct perf_event *event = container_of(entry, struct perf_event, pending);
5904 rctx = perf_swevent_get_recursion_context();
5906 * If we 'fail' here, that's OK, it means recursion is already disabled
5907 * and we won't recurse 'further'.
5910 perf_pending_event_disable(event);
5912 if (event->pending_wakeup) {
5913 event->pending_wakeup = 0;
5914 perf_event_wakeup(event);
5918 perf_swevent_put_recursion_context(rctx);
5922 * We assume there is only KVM supporting the callbacks.
5923 * Later on, we might change it to a list if there is
5924 * another virtualization implementation supporting the callbacks.
5926 struct perf_guest_info_callbacks *perf_guest_cbs;
5928 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5930 perf_guest_cbs = cbs;
5933 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5935 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5937 perf_guest_cbs = NULL;
5940 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5943 perf_output_sample_regs(struct perf_output_handle *handle,
5944 struct pt_regs *regs, u64 mask)
5947 DECLARE_BITMAP(_mask, 64);
5949 bitmap_from_u64(_mask, mask);
5950 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5953 val = perf_reg_value(regs, bit);
5954 perf_output_put(handle, val);
5958 static void perf_sample_regs_user(struct perf_regs *regs_user,
5959 struct pt_regs *regs,
5960 struct pt_regs *regs_user_copy)
5962 if (user_mode(regs)) {
5963 regs_user->abi = perf_reg_abi(current);
5964 regs_user->regs = regs;
5965 } else if (!(current->flags & PF_KTHREAD)) {
5966 perf_get_regs_user(regs_user, regs, regs_user_copy);
5968 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5969 regs_user->regs = NULL;
5973 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5974 struct pt_regs *regs)
5976 regs_intr->regs = regs;
5977 regs_intr->abi = perf_reg_abi(current);
5982 * Get remaining task size from user stack pointer.
5984 * It'd be better to take stack vma map and limit this more
5985 * precisly, but there's no way to get it safely under interrupt,
5986 * so using TASK_SIZE as limit.
5988 static u64 perf_ustack_task_size(struct pt_regs *regs)
5990 unsigned long addr = perf_user_stack_pointer(regs);
5992 if (!addr || addr >= TASK_SIZE)
5995 return TASK_SIZE - addr;
5999 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6000 struct pt_regs *regs)
6004 /* No regs, no stack pointer, no dump. */
6009 * Check if we fit in with the requested stack size into the:
6011 * If we don't, we limit the size to the TASK_SIZE.
6013 * - remaining sample size
6014 * If we don't, we customize the stack size to
6015 * fit in to the remaining sample size.
6018 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6019 stack_size = min(stack_size, (u16) task_size);
6021 /* Current header size plus static size and dynamic size. */
6022 header_size += 2 * sizeof(u64);
6024 /* Do we fit in with the current stack dump size? */
6025 if ((u16) (header_size + stack_size) < header_size) {
6027 * If we overflow the maximum size for the sample,
6028 * we customize the stack dump size to fit in.
6030 stack_size = USHRT_MAX - header_size - sizeof(u64);
6031 stack_size = round_up(stack_size, sizeof(u64));
6038 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6039 struct pt_regs *regs)
6041 /* Case of a kernel thread, nothing to dump */
6044 perf_output_put(handle, size);
6054 * - the size requested by user or the best one we can fit
6055 * in to the sample max size
6057 * - user stack dump data
6059 * - the actual dumped size
6063 perf_output_put(handle, dump_size);
6066 sp = perf_user_stack_pointer(regs);
6069 rem = __output_copy_user(handle, (void *) sp, dump_size);
6071 dyn_size = dump_size - rem;
6073 perf_output_skip(handle, rem);
6076 perf_output_put(handle, dyn_size);
6080 static void __perf_event_header__init_id(struct perf_event_header *header,
6081 struct perf_sample_data *data,
6082 struct perf_event *event)
6084 u64 sample_type = event->attr.sample_type;
6086 data->type = sample_type;
6087 header->size += event->id_header_size;
6089 if (sample_type & PERF_SAMPLE_TID) {
6090 /* namespace issues */
6091 data->tid_entry.pid = perf_event_pid(event, current);
6092 data->tid_entry.tid = perf_event_tid(event, current);
6095 if (sample_type & PERF_SAMPLE_TIME)
6096 data->time = perf_event_clock(event);
6098 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6099 data->id = primary_event_id(event);
6101 if (sample_type & PERF_SAMPLE_STREAM_ID)
6102 data->stream_id = event->id;
6104 if (sample_type & PERF_SAMPLE_CPU) {
6105 data->cpu_entry.cpu = raw_smp_processor_id();
6106 data->cpu_entry.reserved = 0;
6110 void perf_event_header__init_id(struct perf_event_header *header,
6111 struct perf_sample_data *data,
6112 struct perf_event *event)
6114 if (event->attr.sample_id_all)
6115 __perf_event_header__init_id(header, data, event);
6118 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6119 struct perf_sample_data *data)
6121 u64 sample_type = data->type;
6123 if (sample_type & PERF_SAMPLE_TID)
6124 perf_output_put(handle, data->tid_entry);
6126 if (sample_type & PERF_SAMPLE_TIME)
6127 perf_output_put(handle, data->time);
6129 if (sample_type & PERF_SAMPLE_ID)
6130 perf_output_put(handle, data->id);
6132 if (sample_type & PERF_SAMPLE_STREAM_ID)
6133 perf_output_put(handle, data->stream_id);
6135 if (sample_type & PERF_SAMPLE_CPU)
6136 perf_output_put(handle, data->cpu_entry);
6138 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6139 perf_output_put(handle, data->id);
6142 void perf_event__output_id_sample(struct perf_event *event,
6143 struct perf_output_handle *handle,
6144 struct perf_sample_data *sample)
6146 if (event->attr.sample_id_all)
6147 __perf_event__output_id_sample(handle, sample);
6150 static void perf_output_read_one(struct perf_output_handle *handle,
6151 struct perf_event *event,
6152 u64 enabled, u64 running)
6154 u64 read_format = event->attr.read_format;
6158 values[n++] = perf_event_count(event);
6159 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6160 values[n++] = enabled +
6161 atomic64_read(&event->child_total_time_enabled);
6163 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6164 values[n++] = running +
6165 atomic64_read(&event->child_total_time_running);
6167 if (read_format & PERF_FORMAT_ID)
6168 values[n++] = primary_event_id(event);
6170 __output_copy(handle, values, n * sizeof(u64));
6173 static void perf_output_read_group(struct perf_output_handle *handle,
6174 struct perf_event *event,
6175 u64 enabled, u64 running)
6177 struct perf_event *leader = event->group_leader, *sub;
6178 u64 read_format = event->attr.read_format;
6182 values[n++] = 1 + leader->nr_siblings;
6184 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6185 values[n++] = enabled;
6187 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6188 values[n++] = running;
6190 if ((leader != event) &&
6191 (leader->state == PERF_EVENT_STATE_ACTIVE))
6192 leader->pmu->read(leader);
6194 values[n++] = perf_event_count(leader);
6195 if (read_format & PERF_FORMAT_ID)
6196 values[n++] = primary_event_id(leader);
6198 __output_copy(handle, values, n * sizeof(u64));
6200 for_each_sibling_event(sub, leader) {
6203 if ((sub != event) &&
6204 (sub->state == PERF_EVENT_STATE_ACTIVE))
6205 sub->pmu->read(sub);
6207 values[n++] = perf_event_count(sub);
6208 if (read_format & PERF_FORMAT_ID)
6209 values[n++] = primary_event_id(sub);
6211 __output_copy(handle, values, n * sizeof(u64));
6215 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6216 PERF_FORMAT_TOTAL_TIME_RUNNING)
6219 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6221 * The problem is that its both hard and excessively expensive to iterate the
6222 * child list, not to mention that its impossible to IPI the children running
6223 * on another CPU, from interrupt/NMI context.
6225 static void perf_output_read(struct perf_output_handle *handle,
6226 struct perf_event *event)
6228 u64 enabled = 0, running = 0, now;
6229 u64 read_format = event->attr.read_format;
6232 * compute total_time_enabled, total_time_running
6233 * based on snapshot values taken when the event
6234 * was last scheduled in.
6236 * we cannot simply called update_context_time()
6237 * because of locking issue as we are called in
6240 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6241 calc_timer_values(event, &now, &enabled, &running);
6243 if (event->attr.read_format & PERF_FORMAT_GROUP)
6244 perf_output_read_group(handle, event, enabled, running);
6246 perf_output_read_one(handle, event, enabled, running);
6249 void perf_output_sample(struct perf_output_handle *handle,
6250 struct perf_event_header *header,
6251 struct perf_sample_data *data,
6252 struct perf_event *event)
6254 u64 sample_type = data->type;
6256 perf_output_put(handle, *header);
6258 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6259 perf_output_put(handle, data->id);
6261 if (sample_type & PERF_SAMPLE_IP)
6262 perf_output_put(handle, data->ip);
6264 if (sample_type & PERF_SAMPLE_TID)
6265 perf_output_put(handle, data->tid_entry);
6267 if (sample_type & PERF_SAMPLE_TIME)
6268 perf_output_put(handle, data->time);
6270 if (sample_type & PERF_SAMPLE_ADDR)
6271 perf_output_put(handle, data->addr);
6273 if (sample_type & PERF_SAMPLE_ID)
6274 perf_output_put(handle, data->id);
6276 if (sample_type & PERF_SAMPLE_STREAM_ID)
6277 perf_output_put(handle, data->stream_id);
6279 if (sample_type & PERF_SAMPLE_CPU)
6280 perf_output_put(handle, data->cpu_entry);
6282 if (sample_type & PERF_SAMPLE_PERIOD)
6283 perf_output_put(handle, data->period);
6285 if (sample_type & PERF_SAMPLE_READ)
6286 perf_output_read(handle, event);
6288 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6291 size += data->callchain->nr;
6292 size *= sizeof(u64);
6293 __output_copy(handle, data->callchain, size);
6296 if (sample_type & PERF_SAMPLE_RAW) {
6297 struct perf_raw_record *raw = data->raw;
6300 struct perf_raw_frag *frag = &raw->frag;
6302 perf_output_put(handle, raw->size);
6305 __output_custom(handle, frag->copy,
6306 frag->data, frag->size);
6308 __output_copy(handle, frag->data,
6311 if (perf_raw_frag_last(frag))
6316 __output_skip(handle, NULL, frag->pad);
6322 .size = sizeof(u32),
6325 perf_output_put(handle, raw);
6329 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6330 if (data->br_stack) {
6333 size = data->br_stack->nr
6334 * sizeof(struct perf_branch_entry);
6336 perf_output_put(handle, data->br_stack->nr);
6337 perf_output_copy(handle, data->br_stack->entries, size);
6340 * we always store at least the value of nr
6343 perf_output_put(handle, nr);
6347 if (sample_type & PERF_SAMPLE_REGS_USER) {
6348 u64 abi = data->regs_user.abi;
6351 * If there are no regs to dump, notice it through
6352 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6354 perf_output_put(handle, abi);
6357 u64 mask = event->attr.sample_regs_user;
6358 perf_output_sample_regs(handle,
6359 data->regs_user.regs,
6364 if (sample_type & PERF_SAMPLE_STACK_USER) {
6365 perf_output_sample_ustack(handle,
6366 data->stack_user_size,
6367 data->regs_user.regs);
6370 if (sample_type & PERF_SAMPLE_WEIGHT)
6371 perf_output_put(handle, data->weight);
6373 if (sample_type & PERF_SAMPLE_DATA_SRC)
6374 perf_output_put(handle, data->data_src.val);
6376 if (sample_type & PERF_SAMPLE_TRANSACTION)
6377 perf_output_put(handle, data->txn);
6379 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6380 u64 abi = data->regs_intr.abi;
6382 * If there are no regs to dump, notice it through
6383 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6385 perf_output_put(handle, abi);
6388 u64 mask = event->attr.sample_regs_intr;
6390 perf_output_sample_regs(handle,
6391 data->regs_intr.regs,
6396 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6397 perf_output_put(handle, data->phys_addr);
6399 if (!event->attr.watermark) {
6400 int wakeup_events = event->attr.wakeup_events;
6402 if (wakeup_events) {
6403 struct ring_buffer *rb = handle->rb;
6404 int events = local_inc_return(&rb->events);
6406 if (events >= wakeup_events) {
6407 local_sub(wakeup_events, &rb->events);
6408 local_inc(&rb->wakeup);
6414 static u64 perf_virt_to_phys(u64 virt)
6417 struct page *p = NULL;
6422 if (virt >= TASK_SIZE) {
6423 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6424 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6425 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6426 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6429 * Walking the pages tables for user address.
6430 * Interrupts are disabled, so it prevents any tear down
6431 * of the page tables.
6432 * Try IRQ-safe __get_user_pages_fast first.
6433 * If failed, leave phys_addr as 0.
6435 if (current->mm != NULL) {
6436 pagefault_disable();
6437 if (__get_user_pages_fast(virt, 1, 0, &p) == 1)
6438 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6449 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6451 struct perf_callchain_entry *
6452 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6454 bool kernel = !event->attr.exclude_callchain_kernel;
6455 bool user = !event->attr.exclude_callchain_user;
6456 /* Disallow cross-task user callchains. */
6457 bool crosstask = event->ctx->task && event->ctx->task != current;
6458 const u32 max_stack = event->attr.sample_max_stack;
6459 struct perf_callchain_entry *callchain;
6461 if (!kernel && !user)
6462 return &__empty_callchain;
6464 callchain = get_perf_callchain(regs, 0, kernel, user,
6465 max_stack, crosstask, true);
6466 return callchain ?: &__empty_callchain;
6469 void perf_prepare_sample(struct perf_event_header *header,
6470 struct perf_sample_data *data,
6471 struct perf_event *event,
6472 struct pt_regs *regs)
6474 u64 sample_type = event->attr.sample_type;
6476 header->type = PERF_RECORD_SAMPLE;
6477 header->size = sizeof(*header) + event->header_size;
6480 header->misc |= perf_misc_flags(regs);
6482 __perf_event_header__init_id(header, data, event);
6484 if (sample_type & PERF_SAMPLE_IP)
6485 data->ip = perf_instruction_pointer(regs);
6487 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6490 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6491 data->callchain = perf_callchain(event, regs);
6493 size += data->callchain->nr;
6495 header->size += size * sizeof(u64);
6498 if (sample_type & PERF_SAMPLE_RAW) {
6499 struct perf_raw_record *raw = data->raw;
6503 struct perf_raw_frag *frag = &raw->frag;
6508 if (perf_raw_frag_last(frag))
6513 size = round_up(sum + sizeof(u32), sizeof(u64));
6514 raw->size = size - sizeof(u32);
6515 frag->pad = raw->size - sum;
6520 header->size += size;
6523 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6524 int size = sizeof(u64); /* nr */
6525 if (data->br_stack) {
6526 size += data->br_stack->nr
6527 * sizeof(struct perf_branch_entry);
6529 header->size += size;
6532 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6533 perf_sample_regs_user(&data->regs_user, regs,
6534 &data->regs_user_copy);
6536 if (sample_type & PERF_SAMPLE_REGS_USER) {
6537 /* regs dump ABI info */
6538 int size = sizeof(u64);
6540 if (data->regs_user.regs) {
6541 u64 mask = event->attr.sample_regs_user;
6542 size += hweight64(mask) * sizeof(u64);
6545 header->size += size;
6548 if (sample_type & PERF_SAMPLE_STACK_USER) {
6550 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6551 * processed as the last one or have additional check added
6552 * in case new sample type is added, because we could eat
6553 * up the rest of the sample size.
6555 u16 stack_size = event->attr.sample_stack_user;
6556 u16 size = sizeof(u64);
6558 stack_size = perf_sample_ustack_size(stack_size, header->size,
6559 data->regs_user.regs);
6562 * If there is something to dump, add space for the dump
6563 * itself and for the field that tells the dynamic size,
6564 * which is how many have been actually dumped.
6567 size += sizeof(u64) + stack_size;
6569 data->stack_user_size = stack_size;
6570 header->size += size;
6573 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6574 /* regs dump ABI info */
6575 int size = sizeof(u64);
6577 perf_sample_regs_intr(&data->regs_intr, regs);
6579 if (data->regs_intr.regs) {
6580 u64 mask = event->attr.sample_regs_intr;
6582 size += hweight64(mask) * sizeof(u64);
6585 header->size += size;
6588 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6589 data->phys_addr = perf_virt_to_phys(data->addr);
6592 static __always_inline void
6593 __perf_event_output(struct perf_event *event,
6594 struct perf_sample_data *data,
6595 struct pt_regs *regs,
6596 int (*output_begin)(struct perf_output_handle *,
6597 struct perf_event *,
6600 struct perf_output_handle handle;
6601 struct perf_event_header header;
6603 /* protect the callchain buffers */
6606 perf_prepare_sample(&header, data, event, regs);
6608 if (output_begin(&handle, event, header.size))
6611 perf_output_sample(&handle, &header, data, event);
6613 perf_output_end(&handle);
6620 perf_event_output_forward(struct perf_event *event,
6621 struct perf_sample_data *data,
6622 struct pt_regs *regs)
6624 __perf_event_output(event, data, regs, perf_output_begin_forward);
6628 perf_event_output_backward(struct perf_event *event,
6629 struct perf_sample_data *data,
6630 struct pt_regs *regs)
6632 __perf_event_output(event, data, regs, perf_output_begin_backward);
6636 perf_event_output(struct perf_event *event,
6637 struct perf_sample_data *data,
6638 struct pt_regs *regs)
6640 __perf_event_output(event, data, regs, perf_output_begin);
6647 struct perf_read_event {
6648 struct perf_event_header header;
6655 perf_event_read_event(struct perf_event *event,
6656 struct task_struct *task)
6658 struct perf_output_handle handle;
6659 struct perf_sample_data sample;
6660 struct perf_read_event read_event = {
6662 .type = PERF_RECORD_READ,
6664 .size = sizeof(read_event) + event->read_size,
6666 .pid = perf_event_pid(event, task),
6667 .tid = perf_event_tid(event, task),
6671 perf_event_header__init_id(&read_event.header, &sample, event);
6672 ret = perf_output_begin(&handle, event, read_event.header.size);
6676 perf_output_put(&handle, read_event);
6677 perf_output_read(&handle, event);
6678 perf_event__output_id_sample(event, &handle, &sample);
6680 perf_output_end(&handle);
6683 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6686 perf_iterate_ctx(struct perf_event_context *ctx,
6687 perf_iterate_f output,
6688 void *data, bool all)
6690 struct perf_event *event;
6692 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6694 if (event->state < PERF_EVENT_STATE_INACTIVE)
6696 if (!event_filter_match(event))
6700 output(event, data);
6704 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6706 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6707 struct perf_event *event;
6709 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6711 * Skip events that are not fully formed yet; ensure that
6712 * if we observe event->ctx, both event and ctx will be
6713 * complete enough. See perf_install_in_context().
6715 if (!smp_load_acquire(&event->ctx))
6718 if (event->state < PERF_EVENT_STATE_INACTIVE)
6720 if (!event_filter_match(event))
6722 output(event, data);
6727 * Iterate all events that need to receive side-band events.
6729 * For new callers; ensure that account_pmu_sb_event() includes
6730 * your event, otherwise it might not get delivered.
6733 perf_iterate_sb(perf_iterate_f output, void *data,
6734 struct perf_event_context *task_ctx)
6736 struct perf_event_context *ctx;
6743 * If we have task_ctx != NULL we only notify the task context itself.
6744 * The task_ctx is set only for EXIT events before releasing task
6748 perf_iterate_ctx(task_ctx, output, data, false);
6752 perf_iterate_sb_cpu(output, data);
6754 for_each_task_context_nr(ctxn) {
6755 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6757 perf_iterate_ctx(ctx, output, data, false);
6765 * Clear all file-based filters at exec, they'll have to be
6766 * re-instated when/if these objects are mmapped again.
6768 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6770 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6771 struct perf_addr_filter *filter;
6772 unsigned int restart = 0, count = 0;
6773 unsigned long flags;
6775 if (!has_addr_filter(event))
6778 raw_spin_lock_irqsave(&ifh->lock, flags);
6779 list_for_each_entry(filter, &ifh->list, entry) {
6780 if (filter->path.dentry) {
6781 event->addr_filter_ranges[count].start = 0;
6782 event->addr_filter_ranges[count].size = 0;
6790 event->addr_filters_gen++;
6791 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6794 perf_event_stop(event, 1);
6797 void perf_event_exec(void)
6799 struct perf_event_context *ctx;
6803 for_each_task_context_nr(ctxn) {
6804 ctx = current->perf_event_ctxp[ctxn];
6808 perf_event_enable_on_exec(ctxn);
6810 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6816 struct remote_output {
6817 struct ring_buffer *rb;
6821 static void __perf_event_output_stop(struct perf_event *event, void *data)
6823 struct perf_event *parent = event->parent;
6824 struct remote_output *ro = data;
6825 struct ring_buffer *rb = ro->rb;
6826 struct stop_event_data sd = {
6830 if (!has_aux(event))
6837 * In case of inheritance, it will be the parent that links to the
6838 * ring-buffer, but it will be the child that's actually using it.
6840 * We are using event::rb to determine if the event should be stopped,
6841 * however this may race with ring_buffer_attach() (through set_output),
6842 * which will make us skip the event that actually needs to be stopped.
6843 * So ring_buffer_attach() has to stop an aux event before re-assigning
6846 if (rcu_dereference(parent->rb) == rb)
6847 ro->err = __perf_event_stop(&sd);
6850 static int __perf_pmu_output_stop(void *info)
6852 struct perf_event *event = info;
6853 struct pmu *pmu = event->ctx->pmu;
6854 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6855 struct remote_output ro = {
6860 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6861 if (cpuctx->task_ctx)
6862 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6869 static void perf_pmu_output_stop(struct perf_event *event)
6871 struct perf_event *iter;
6876 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6878 * For per-CPU events, we need to make sure that neither they
6879 * nor their children are running; for cpu==-1 events it's
6880 * sufficient to stop the event itself if it's active, since
6881 * it can't have children.
6885 cpu = READ_ONCE(iter->oncpu);
6890 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6891 if (err == -EAGAIN) {
6900 * task tracking -- fork/exit
6902 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6905 struct perf_task_event {
6906 struct task_struct *task;
6907 struct perf_event_context *task_ctx;
6910 struct perf_event_header header;
6920 static int perf_event_task_match(struct perf_event *event)
6922 return event->attr.comm || event->attr.mmap ||
6923 event->attr.mmap2 || event->attr.mmap_data ||
6927 static void perf_event_task_output(struct perf_event *event,
6930 struct perf_task_event *task_event = data;
6931 struct perf_output_handle handle;
6932 struct perf_sample_data sample;
6933 struct task_struct *task = task_event->task;
6934 int ret, size = task_event->event_id.header.size;
6936 if (!perf_event_task_match(event))
6939 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6941 ret = perf_output_begin(&handle, event,
6942 task_event->event_id.header.size);
6946 task_event->event_id.pid = perf_event_pid(event, task);
6947 task_event->event_id.tid = perf_event_tid(event, task);
6949 if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
6950 task_event->event_id.ppid = perf_event_pid(event,
6952 task_event->event_id.ptid = perf_event_pid(event,
6954 } else { /* PERF_RECORD_FORK */
6955 task_event->event_id.ppid = perf_event_pid(event, current);
6956 task_event->event_id.ptid = perf_event_tid(event, current);
6959 task_event->event_id.time = perf_event_clock(event);
6961 perf_output_put(&handle, task_event->event_id);
6963 perf_event__output_id_sample(event, &handle, &sample);
6965 perf_output_end(&handle);
6967 task_event->event_id.header.size = size;
6970 static void perf_event_task(struct task_struct *task,
6971 struct perf_event_context *task_ctx,
6974 struct perf_task_event task_event;
6976 if (!atomic_read(&nr_comm_events) &&
6977 !atomic_read(&nr_mmap_events) &&
6978 !atomic_read(&nr_task_events))
6981 task_event = (struct perf_task_event){
6983 .task_ctx = task_ctx,
6986 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6988 .size = sizeof(task_event.event_id),
6998 perf_iterate_sb(perf_event_task_output,
7003 void perf_event_fork(struct task_struct *task)
7005 perf_event_task(task, NULL, 1);
7006 perf_event_namespaces(task);
7013 struct perf_comm_event {
7014 struct task_struct *task;
7019 struct perf_event_header header;
7026 static int perf_event_comm_match(struct perf_event *event)
7028 return event->attr.comm;
7031 static void perf_event_comm_output(struct perf_event *event,
7034 struct perf_comm_event *comm_event = data;
7035 struct perf_output_handle handle;
7036 struct perf_sample_data sample;
7037 int size = comm_event->event_id.header.size;
7040 if (!perf_event_comm_match(event))
7043 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7044 ret = perf_output_begin(&handle, event,
7045 comm_event->event_id.header.size);
7050 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7051 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7053 perf_output_put(&handle, comm_event->event_id);
7054 __output_copy(&handle, comm_event->comm,
7055 comm_event->comm_size);
7057 perf_event__output_id_sample(event, &handle, &sample);
7059 perf_output_end(&handle);
7061 comm_event->event_id.header.size = size;
7064 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7066 char comm[TASK_COMM_LEN];
7069 memset(comm, 0, sizeof(comm));
7070 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7071 size = ALIGN(strlen(comm)+1, sizeof(u64));
7073 comm_event->comm = comm;
7074 comm_event->comm_size = size;
7076 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7078 perf_iterate_sb(perf_event_comm_output,
7083 void perf_event_comm(struct task_struct *task, bool exec)
7085 struct perf_comm_event comm_event;
7087 if (!atomic_read(&nr_comm_events))
7090 comm_event = (struct perf_comm_event){
7096 .type = PERF_RECORD_COMM,
7097 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7105 perf_event_comm_event(&comm_event);
7109 * namespaces tracking
7112 struct perf_namespaces_event {
7113 struct task_struct *task;
7116 struct perf_event_header header;
7121 struct perf_ns_link_info link_info[NR_NAMESPACES];
7125 static int perf_event_namespaces_match(struct perf_event *event)
7127 return event->attr.namespaces;
7130 static void perf_event_namespaces_output(struct perf_event *event,
7133 struct perf_namespaces_event *namespaces_event = data;
7134 struct perf_output_handle handle;
7135 struct perf_sample_data sample;
7136 u16 header_size = namespaces_event->event_id.header.size;
7139 if (!perf_event_namespaces_match(event))
7142 perf_event_header__init_id(&namespaces_event->event_id.header,
7144 ret = perf_output_begin(&handle, event,
7145 namespaces_event->event_id.header.size);
7149 namespaces_event->event_id.pid = perf_event_pid(event,
7150 namespaces_event->task);
7151 namespaces_event->event_id.tid = perf_event_tid(event,
7152 namespaces_event->task);
7154 perf_output_put(&handle, namespaces_event->event_id);
7156 perf_event__output_id_sample(event, &handle, &sample);
7158 perf_output_end(&handle);
7160 namespaces_event->event_id.header.size = header_size;
7163 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7164 struct task_struct *task,
7165 const struct proc_ns_operations *ns_ops)
7167 struct path ns_path;
7168 struct inode *ns_inode;
7171 error = ns_get_path(&ns_path, task, ns_ops);
7173 ns_inode = ns_path.dentry->d_inode;
7174 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7175 ns_link_info->ino = ns_inode->i_ino;
7180 void perf_event_namespaces(struct task_struct *task)
7182 struct perf_namespaces_event namespaces_event;
7183 struct perf_ns_link_info *ns_link_info;
7185 if (!atomic_read(&nr_namespaces_events))
7188 namespaces_event = (struct perf_namespaces_event){
7192 .type = PERF_RECORD_NAMESPACES,
7194 .size = sizeof(namespaces_event.event_id),
7198 .nr_namespaces = NR_NAMESPACES,
7199 /* .link_info[NR_NAMESPACES] */
7203 ns_link_info = namespaces_event.event_id.link_info;
7205 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7206 task, &mntns_operations);
7208 #ifdef CONFIG_USER_NS
7209 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7210 task, &userns_operations);
7212 #ifdef CONFIG_NET_NS
7213 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7214 task, &netns_operations);
7216 #ifdef CONFIG_UTS_NS
7217 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7218 task, &utsns_operations);
7220 #ifdef CONFIG_IPC_NS
7221 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7222 task, &ipcns_operations);
7224 #ifdef CONFIG_PID_NS
7225 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7226 task, &pidns_operations);
7228 #ifdef CONFIG_CGROUPS
7229 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7230 task, &cgroupns_operations);
7233 perf_iterate_sb(perf_event_namespaces_output,
7242 struct perf_mmap_event {
7243 struct vm_area_struct *vma;
7245 const char *file_name;
7253 struct perf_event_header header;
7263 static int perf_event_mmap_match(struct perf_event *event,
7266 struct perf_mmap_event *mmap_event = data;
7267 struct vm_area_struct *vma = mmap_event->vma;
7268 int executable = vma->vm_flags & VM_EXEC;
7270 return (!executable && event->attr.mmap_data) ||
7271 (executable && (event->attr.mmap || event->attr.mmap2));
7274 static void perf_event_mmap_output(struct perf_event *event,
7277 struct perf_mmap_event *mmap_event = data;
7278 struct perf_output_handle handle;
7279 struct perf_sample_data sample;
7280 int size = mmap_event->event_id.header.size;
7281 u32 type = mmap_event->event_id.header.type;
7284 if (!perf_event_mmap_match(event, data))
7287 if (event->attr.mmap2) {
7288 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7289 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7290 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7291 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7292 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7293 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7294 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7297 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7298 ret = perf_output_begin(&handle, event,
7299 mmap_event->event_id.header.size);
7303 mmap_event->event_id.pid = perf_event_pid(event, current);
7304 mmap_event->event_id.tid = perf_event_tid(event, current);
7306 perf_output_put(&handle, mmap_event->event_id);
7308 if (event->attr.mmap2) {
7309 perf_output_put(&handle, mmap_event->maj);
7310 perf_output_put(&handle, mmap_event->min);
7311 perf_output_put(&handle, mmap_event->ino);
7312 perf_output_put(&handle, mmap_event->ino_generation);
7313 perf_output_put(&handle, mmap_event->prot);
7314 perf_output_put(&handle, mmap_event->flags);
7317 __output_copy(&handle, mmap_event->file_name,
7318 mmap_event->file_size);
7320 perf_event__output_id_sample(event, &handle, &sample);
7322 perf_output_end(&handle);
7324 mmap_event->event_id.header.size = size;
7325 mmap_event->event_id.header.type = type;
7328 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7330 struct vm_area_struct *vma = mmap_event->vma;
7331 struct file *file = vma->vm_file;
7332 int maj = 0, min = 0;
7333 u64 ino = 0, gen = 0;
7334 u32 prot = 0, flags = 0;
7340 if (vma->vm_flags & VM_READ)
7342 if (vma->vm_flags & VM_WRITE)
7344 if (vma->vm_flags & VM_EXEC)
7347 if (vma->vm_flags & VM_MAYSHARE)
7350 flags = MAP_PRIVATE;
7352 if (vma->vm_flags & VM_DENYWRITE)
7353 flags |= MAP_DENYWRITE;
7354 if (vma->vm_flags & VM_MAYEXEC)
7355 flags |= MAP_EXECUTABLE;
7356 if (vma->vm_flags & VM_LOCKED)
7357 flags |= MAP_LOCKED;
7358 if (vma->vm_flags & VM_HUGETLB)
7359 flags |= MAP_HUGETLB;
7362 struct inode *inode;
7365 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7371 * d_path() works from the end of the rb backwards, so we
7372 * need to add enough zero bytes after the string to handle
7373 * the 64bit alignment we do later.
7375 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7380 inode = file_inode(vma->vm_file);
7381 dev = inode->i_sb->s_dev;
7383 gen = inode->i_generation;
7389 if (vma->vm_ops && vma->vm_ops->name) {
7390 name = (char *) vma->vm_ops->name(vma);
7395 name = (char *)arch_vma_name(vma);
7399 if (vma->vm_start <= vma->vm_mm->start_brk &&
7400 vma->vm_end >= vma->vm_mm->brk) {
7404 if (vma->vm_start <= vma->vm_mm->start_stack &&
7405 vma->vm_end >= vma->vm_mm->start_stack) {
7415 strlcpy(tmp, name, sizeof(tmp));
7419 * Since our buffer works in 8 byte units we need to align our string
7420 * size to a multiple of 8. However, we must guarantee the tail end is
7421 * zero'd out to avoid leaking random bits to userspace.
7423 size = strlen(name)+1;
7424 while (!IS_ALIGNED(size, sizeof(u64)))
7425 name[size++] = '\0';
7427 mmap_event->file_name = name;
7428 mmap_event->file_size = size;
7429 mmap_event->maj = maj;
7430 mmap_event->min = min;
7431 mmap_event->ino = ino;
7432 mmap_event->ino_generation = gen;
7433 mmap_event->prot = prot;
7434 mmap_event->flags = flags;
7436 if (!(vma->vm_flags & VM_EXEC))
7437 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7439 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7441 perf_iterate_sb(perf_event_mmap_output,
7449 * Check whether inode and address range match filter criteria.
7451 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7452 struct file *file, unsigned long offset,
7455 /* d_inode(NULL) won't be equal to any mapped user-space file */
7456 if (!filter->path.dentry)
7459 if (d_inode(filter->path.dentry) != file_inode(file))
7462 if (filter->offset > offset + size)
7465 if (filter->offset + filter->size < offset)
7471 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
7472 struct vm_area_struct *vma,
7473 struct perf_addr_filter_range *fr)
7475 unsigned long vma_size = vma->vm_end - vma->vm_start;
7476 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7477 struct file *file = vma->vm_file;
7479 if (!perf_addr_filter_match(filter, file, off, vma_size))
7482 if (filter->offset < off) {
7483 fr->start = vma->vm_start;
7484 fr->size = min(vma_size, filter->size - (off - filter->offset));
7486 fr->start = vma->vm_start + filter->offset - off;
7487 fr->size = min(vma->vm_end - fr->start, filter->size);
7493 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7495 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7496 struct vm_area_struct *vma = data;
7497 struct perf_addr_filter *filter;
7498 unsigned int restart = 0, count = 0;
7499 unsigned long flags;
7501 if (!has_addr_filter(event))
7507 raw_spin_lock_irqsave(&ifh->lock, flags);
7508 list_for_each_entry(filter, &ifh->list, entry) {
7509 if (perf_addr_filter_vma_adjust(filter, vma,
7510 &event->addr_filter_ranges[count]))
7517 event->addr_filters_gen++;
7518 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7521 perf_event_stop(event, 1);
7525 * Adjust all task's events' filters to the new vma
7527 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7529 struct perf_event_context *ctx;
7533 * Data tracing isn't supported yet and as such there is no need
7534 * to keep track of anything that isn't related to executable code:
7536 if (!(vma->vm_flags & VM_EXEC))
7540 for_each_task_context_nr(ctxn) {
7541 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7545 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7550 void perf_event_mmap(struct vm_area_struct *vma)
7552 struct perf_mmap_event mmap_event;
7554 if (!atomic_read(&nr_mmap_events))
7557 mmap_event = (struct perf_mmap_event){
7563 .type = PERF_RECORD_MMAP,
7564 .misc = PERF_RECORD_MISC_USER,
7569 .start = vma->vm_start,
7570 .len = vma->vm_end - vma->vm_start,
7571 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7573 /* .maj (attr_mmap2 only) */
7574 /* .min (attr_mmap2 only) */
7575 /* .ino (attr_mmap2 only) */
7576 /* .ino_generation (attr_mmap2 only) */
7577 /* .prot (attr_mmap2 only) */
7578 /* .flags (attr_mmap2 only) */
7581 perf_addr_filters_adjust(vma);
7582 perf_event_mmap_event(&mmap_event);
7585 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7586 unsigned long size, u64 flags)
7588 struct perf_output_handle handle;
7589 struct perf_sample_data sample;
7590 struct perf_aux_event {
7591 struct perf_event_header header;
7597 .type = PERF_RECORD_AUX,
7599 .size = sizeof(rec),
7607 perf_event_header__init_id(&rec.header, &sample, event);
7608 ret = perf_output_begin(&handle, event, rec.header.size);
7613 perf_output_put(&handle, rec);
7614 perf_event__output_id_sample(event, &handle, &sample);
7616 perf_output_end(&handle);
7620 * Lost/dropped samples logging
7622 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7624 struct perf_output_handle handle;
7625 struct perf_sample_data sample;
7629 struct perf_event_header header;
7631 } lost_samples_event = {
7633 .type = PERF_RECORD_LOST_SAMPLES,
7635 .size = sizeof(lost_samples_event),
7640 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7642 ret = perf_output_begin(&handle, event,
7643 lost_samples_event.header.size);
7647 perf_output_put(&handle, lost_samples_event);
7648 perf_event__output_id_sample(event, &handle, &sample);
7649 perf_output_end(&handle);
7653 * context_switch tracking
7656 struct perf_switch_event {
7657 struct task_struct *task;
7658 struct task_struct *next_prev;
7661 struct perf_event_header header;
7667 static int perf_event_switch_match(struct perf_event *event)
7669 return event->attr.context_switch;
7672 static void perf_event_switch_output(struct perf_event *event, void *data)
7674 struct perf_switch_event *se = data;
7675 struct perf_output_handle handle;
7676 struct perf_sample_data sample;
7679 if (!perf_event_switch_match(event))
7682 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7683 if (event->ctx->task) {
7684 se->event_id.header.type = PERF_RECORD_SWITCH;
7685 se->event_id.header.size = sizeof(se->event_id.header);
7687 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7688 se->event_id.header.size = sizeof(se->event_id);
7689 se->event_id.next_prev_pid =
7690 perf_event_pid(event, se->next_prev);
7691 se->event_id.next_prev_tid =
7692 perf_event_tid(event, se->next_prev);
7695 perf_event_header__init_id(&se->event_id.header, &sample, event);
7697 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7701 if (event->ctx->task)
7702 perf_output_put(&handle, se->event_id.header);
7704 perf_output_put(&handle, se->event_id);
7706 perf_event__output_id_sample(event, &handle, &sample);
7708 perf_output_end(&handle);
7711 static void perf_event_switch(struct task_struct *task,
7712 struct task_struct *next_prev, bool sched_in)
7714 struct perf_switch_event switch_event;
7716 /* N.B. caller checks nr_switch_events != 0 */
7718 switch_event = (struct perf_switch_event){
7720 .next_prev = next_prev,
7724 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7727 /* .next_prev_pid */
7728 /* .next_prev_tid */
7732 if (!sched_in && task->state == TASK_RUNNING)
7733 switch_event.event_id.header.misc |=
7734 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
7736 perf_iterate_sb(perf_event_switch_output,
7742 * IRQ throttle logging
7745 static void perf_log_throttle(struct perf_event *event, int enable)
7747 struct perf_output_handle handle;
7748 struct perf_sample_data sample;
7752 struct perf_event_header header;
7756 } throttle_event = {
7758 .type = PERF_RECORD_THROTTLE,
7760 .size = sizeof(throttle_event),
7762 .time = perf_event_clock(event),
7763 .id = primary_event_id(event),
7764 .stream_id = event->id,
7768 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7770 perf_event_header__init_id(&throttle_event.header, &sample, event);
7772 ret = perf_output_begin(&handle, event,
7773 throttle_event.header.size);
7777 perf_output_put(&handle, throttle_event);
7778 perf_event__output_id_sample(event, &handle, &sample);
7779 perf_output_end(&handle);
7782 void perf_event_itrace_started(struct perf_event *event)
7784 event->attach_state |= PERF_ATTACH_ITRACE;
7787 static void perf_log_itrace_start(struct perf_event *event)
7789 struct perf_output_handle handle;
7790 struct perf_sample_data sample;
7791 struct perf_aux_event {
7792 struct perf_event_header header;
7799 event = event->parent;
7801 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7802 event->attach_state & PERF_ATTACH_ITRACE)
7805 rec.header.type = PERF_RECORD_ITRACE_START;
7806 rec.header.misc = 0;
7807 rec.header.size = sizeof(rec);
7808 rec.pid = perf_event_pid(event, current);
7809 rec.tid = perf_event_tid(event, current);
7811 perf_event_header__init_id(&rec.header, &sample, event);
7812 ret = perf_output_begin(&handle, event, rec.header.size);
7817 perf_output_put(&handle, rec);
7818 perf_event__output_id_sample(event, &handle, &sample);
7820 perf_output_end(&handle);
7824 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7826 struct hw_perf_event *hwc = &event->hw;
7830 seq = __this_cpu_read(perf_throttled_seq);
7831 if (seq != hwc->interrupts_seq) {
7832 hwc->interrupts_seq = seq;
7833 hwc->interrupts = 1;
7836 if (unlikely(throttle
7837 && hwc->interrupts >= max_samples_per_tick)) {
7838 __this_cpu_inc(perf_throttled_count);
7839 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7840 hwc->interrupts = MAX_INTERRUPTS;
7841 perf_log_throttle(event, 0);
7846 if (event->attr.freq) {
7847 u64 now = perf_clock();
7848 s64 delta = now - hwc->freq_time_stamp;
7850 hwc->freq_time_stamp = now;
7852 if (delta > 0 && delta < 2*TICK_NSEC)
7853 perf_adjust_period(event, delta, hwc->last_period, true);
7859 int perf_event_account_interrupt(struct perf_event *event)
7861 return __perf_event_account_interrupt(event, 1);
7865 * Generic event overflow handling, sampling.
7868 static int __perf_event_overflow(struct perf_event *event,
7869 int throttle, struct perf_sample_data *data,
7870 struct pt_regs *regs)
7872 int events = atomic_read(&event->event_limit);
7876 * Non-sampling counters might still use the PMI to fold short
7877 * hardware counters, ignore those.
7879 if (unlikely(!is_sampling_event(event)))
7882 ret = __perf_event_account_interrupt(event, throttle);
7885 * XXX event_limit might not quite work as expected on inherited
7889 event->pending_kill = POLL_IN;
7890 if (events && atomic_dec_and_test(&event->event_limit)) {
7892 event->pending_kill = POLL_HUP;
7894 perf_event_disable_inatomic(event);
7897 READ_ONCE(event->overflow_handler)(event, data, regs);
7899 if (*perf_event_fasync(event) && event->pending_kill) {
7900 event->pending_wakeup = 1;
7901 irq_work_queue(&event->pending);
7907 int perf_event_overflow(struct perf_event *event,
7908 struct perf_sample_data *data,
7909 struct pt_regs *regs)
7911 return __perf_event_overflow(event, 1, data, regs);
7915 * Generic software event infrastructure
7918 struct swevent_htable {
7919 struct swevent_hlist *swevent_hlist;
7920 struct mutex hlist_mutex;
7923 /* Recursion avoidance in each contexts */
7924 int recursion[PERF_NR_CONTEXTS];
7927 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7930 * We directly increment event->count and keep a second value in
7931 * event->hw.period_left to count intervals. This period event
7932 * is kept in the range [-sample_period, 0] so that we can use the
7936 u64 perf_swevent_set_period(struct perf_event *event)
7938 struct hw_perf_event *hwc = &event->hw;
7939 u64 period = hwc->last_period;
7943 hwc->last_period = hwc->sample_period;
7946 old = val = local64_read(&hwc->period_left);
7950 nr = div64_u64(period + val, period);
7951 offset = nr * period;
7953 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7959 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7960 struct perf_sample_data *data,
7961 struct pt_regs *regs)
7963 struct hw_perf_event *hwc = &event->hw;
7967 overflow = perf_swevent_set_period(event);
7969 if (hwc->interrupts == MAX_INTERRUPTS)
7972 for (; overflow; overflow--) {
7973 if (__perf_event_overflow(event, throttle,
7976 * We inhibit the overflow from happening when
7977 * hwc->interrupts == MAX_INTERRUPTS.
7985 static void perf_swevent_event(struct perf_event *event, u64 nr,
7986 struct perf_sample_data *data,
7987 struct pt_regs *regs)
7989 struct hw_perf_event *hwc = &event->hw;
7991 local64_add(nr, &event->count);
7996 if (!is_sampling_event(event))
7999 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
8001 return perf_swevent_overflow(event, 1, data, regs);
8003 data->period = event->hw.last_period;
8005 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
8006 return perf_swevent_overflow(event, 1, data, regs);
8008 if (local64_add_negative(nr, &hwc->period_left))
8011 perf_swevent_overflow(event, 0, data, regs);
8014 static int perf_exclude_event(struct perf_event *event,
8015 struct pt_regs *regs)
8017 if (event->hw.state & PERF_HES_STOPPED)
8021 if (event->attr.exclude_user && user_mode(regs))
8024 if (event->attr.exclude_kernel && !user_mode(regs))
8031 static int perf_swevent_match(struct perf_event *event,
8032 enum perf_type_id type,
8034 struct perf_sample_data *data,
8035 struct pt_regs *regs)
8037 if (event->attr.type != type)
8040 if (event->attr.config != event_id)
8043 if (perf_exclude_event(event, regs))
8049 static inline u64 swevent_hash(u64 type, u32 event_id)
8051 u64 val = event_id | (type << 32);
8053 return hash_64(val, SWEVENT_HLIST_BITS);
8056 static inline struct hlist_head *
8057 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
8059 u64 hash = swevent_hash(type, event_id);
8061 return &hlist->heads[hash];
8064 /* For the read side: events when they trigger */
8065 static inline struct hlist_head *
8066 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8068 struct swevent_hlist *hlist;
8070 hlist = rcu_dereference(swhash->swevent_hlist);
8074 return __find_swevent_head(hlist, type, event_id);
8077 /* For the event head insertion and removal in the hlist */
8078 static inline struct hlist_head *
8079 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8081 struct swevent_hlist *hlist;
8082 u32 event_id = event->attr.config;
8083 u64 type = event->attr.type;
8086 * Event scheduling is always serialized against hlist allocation
8087 * and release. Which makes the protected version suitable here.
8088 * The context lock guarantees that.
8090 hlist = rcu_dereference_protected(swhash->swevent_hlist,
8091 lockdep_is_held(&event->ctx->lock));
8095 return __find_swevent_head(hlist, type, event_id);
8098 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8100 struct perf_sample_data *data,
8101 struct pt_regs *regs)
8103 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8104 struct perf_event *event;
8105 struct hlist_head *head;
8108 head = find_swevent_head_rcu(swhash, type, event_id);
8112 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8113 if (perf_swevent_match(event, type, event_id, data, regs))
8114 perf_swevent_event(event, nr, data, regs);
8120 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8122 int perf_swevent_get_recursion_context(void)
8124 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8126 return get_recursion_context(swhash->recursion);
8128 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8130 void perf_swevent_put_recursion_context(int rctx)
8132 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8134 put_recursion_context(swhash->recursion, rctx);
8137 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8139 struct perf_sample_data data;
8141 if (WARN_ON_ONCE(!regs))
8144 perf_sample_data_init(&data, addr, 0);
8145 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8148 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8152 preempt_disable_notrace();
8153 rctx = perf_swevent_get_recursion_context();
8154 if (unlikely(rctx < 0))
8157 ___perf_sw_event(event_id, nr, regs, addr);
8159 perf_swevent_put_recursion_context(rctx);
8161 preempt_enable_notrace();
8164 static void perf_swevent_read(struct perf_event *event)
8168 static int perf_swevent_add(struct perf_event *event, int flags)
8170 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8171 struct hw_perf_event *hwc = &event->hw;
8172 struct hlist_head *head;
8174 if (is_sampling_event(event)) {
8175 hwc->last_period = hwc->sample_period;
8176 perf_swevent_set_period(event);
8179 hwc->state = !(flags & PERF_EF_START);
8181 head = find_swevent_head(swhash, event);
8182 if (WARN_ON_ONCE(!head))
8185 hlist_add_head_rcu(&event->hlist_entry, head);
8186 perf_event_update_userpage(event);
8191 static void perf_swevent_del(struct perf_event *event, int flags)
8193 hlist_del_rcu(&event->hlist_entry);
8196 static void perf_swevent_start(struct perf_event *event, int flags)
8198 event->hw.state = 0;
8201 static void perf_swevent_stop(struct perf_event *event, int flags)
8203 event->hw.state = PERF_HES_STOPPED;
8206 /* Deref the hlist from the update side */
8207 static inline struct swevent_hlist *
8208 swevent_hlist_deref(struct swevent_htable *swhash)
8210 return rcu_dereference_protected(swhash->swevent_hlist,
8211 lockdep_is_held(&swhash->hlist_mutex));
8214 static void swevent_hlist_release(struct swevent_htable *swhash)
8216 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
8221 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
8222 kfree_rcu(hlist, rcu_head);
8225 static void swevent_hlist_put_cpu(int cpu)
8227 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8229 mutex_lock(&swhash->hlist_mutex);
8231 if (!--swhash->hlist_refcount)
8232 swevent_hlist_release(swhash);
8234 mutex_unlock(&swhash->hlist_mutex);
8237 static void swevent_hlist_put(void)
8241 for_each_possible_cpu(cpu)
8242 swevent_hlist_put_cpu(cpu);
8245 static int swevent_hlist_get_cpu(int cpu)
8247 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8250 mutex_lock(&swhash->hlist_mutex);
8251 if (!swevent_hlist_deref(swhash) &&
8252 cpumask_test_cpu(cpu, perf_online_mask)) {
8253 struct swevent_hlist *hlist;
8255 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
8260 rcu_assign_pointer(swhash->swevent_hlist, hlist);
8262 swhash->hlist_refcount++;
8264 mutex_unlock(&swhash->hlist_mutex);
8269 static int swevent_hlist_get(void)
8271 int err, cpu, failed_cpu;
8273 mutex_lock(&pmus_lock);
8274 for_each_possible_cpu(cpu) {
8275 err = swevent_hlist_get_cpu(cpu);
8281 mutex_unlock(&pmus_lock);
8284 for_each_possible_cpu(cpu) {
8285 if (cpu == failed_cpu)
8287 swevent_hlist_put_cpu(cpu);
8289 mutex_unlock(&pmus_lock);
8293 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
8295 static void sw_perf_event_destroy(struct perf_event *event)
8297 u64 event_id = event->attr.config;
8299 WARN_ON(event->parent);
8301 static_key_slow_dec(&perf_swevent_enabled[event_id]);
8302 swevent_hlist_put();
8305 static int perf_swevent_init(struct perf_event *event)
8307 u64 event_id = event->attr.config;
8309 if (event->attr.type != PERF_TYPE_SOFTWARE)
8313 * no branch sampling for software events
8315 if (has_branch_stack(event))
8319 case PERF_COUNT_SW_CPU_CLOCK:
8320 case PERF_COUNT_SW_TASK_CLOCK:
8327 if (event_id >= PERF_COUNT_SW_MAX)
8330 if (!event->parent) {
8333 err = swevent_hlist_get();
8337 static_key_slow_inc(&perf_swevent_enabled[event_id]);
8338 event->destroy = sw_perf_event_destroy;
8344 static struct pmu perf_swevent = {
8345 .task_ctx_nr = perf_sw_context,
8347 .capabilities = PERF_PMU_CAP_NO_NMI,
8349 .event_init = perf_swevent_init,
8350 .add = perf_swevent_add,
8351 .del = perf_swevent_del,
8352 .start = perf_swevent_start,
8353 .stop = perf_swevent_stop,
8354 .read = perf_swevent_read,
8357 #ifdef CONFIG_EVENT_TRACING
8359 static int perf_tp_filter_match(struct perf_event *event,
8360 struct perf_sample_data *data)
8362 void *record = data->raw->frag.data;
8364 /* only top level events have filters set */
8366 event = event->parent;
8368 if (likely(!event->filter) || filter_match_preds(event->filter, record))
8373 static int perf_tp_event_match(struct perf_event *event,
8374 struct perf_sample_data *data,
8375 struct pt_regs *regs)
8377 if (event->hw.state & PERF_HES_STOPPED)
8380 * All tracepoints are from kernel-space.
8382 if (event->attr.exclude_kernel)
8385 if (!perf_tp_filter_match(event, data))
8391 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8392 struct trace_event_call *call, u64 count,
8393 struct pt_regs *regs, struct hlist_head *head,
8394 struct task_struct *task)
8396 if (bpf_prog_array_valid(call)) {
8397 *(struct pt_regs **)raw_data = regs;
8398 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
8399 perf_swevent_put_recursion_context(rctx);
8403 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8406 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8408 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8409 struct pt_regs *regs, struct hlist_head *head, int rctx,
8410 struct task_struct *task)
8412 struct perf_sample_data data;
8413 struct perf_event *event;
8415 struct perf_raw_record raw = {
8422 perf_sample_data_init(&data, 0, 0);
8425 perf_trace_buf_update(record, event_type);
8427 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8428 if (perf_tp_event_match(event, &data, regs))
8429 perf_swevent_event(event, count, &data, regs);
8433 * If we got specified a target task, also iterate its context and
8434 * deliver this event there too.
8436 if (task && task != current) {
8437 struct perf_event_context *ctx;
8438 struct trace_entry *entry = record;
8441 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8445 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8446 if (event->cpu != smp_processor_id())
8448 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8450 if (event->attr.config != entry->type)
8452 if (perf_tp_event_match(event, &data, regs))
8453 perf_swevent_event(event, count, &data, regs);
8459 perf_swevent_put_recursion_context(rctx);
8461 EXPORT_SYMBOL_GPL(perf_tp_event);
8463 static void tp_perf_event_destroy(struct perf_event *event)
8465 perf_trace_destroy(event);
8468 static int perf_tp_event_init(struct perf_event *event)
8472 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8476 * no branch sampling for tracepoint events
8478 if (has_branch_stack(event))
8481 err = perf_trace_init(event);
8485 event->destroy = tp_perf_event_destroy;
8490 static struct pmu perf_tracepoint = {
8491 .task_ctx_nr = perf_sw_context,
8493 .event_init = perf_tp_event_init,
8494 .add = perf_trace_add,
8495 .del = perf_trace_del,
8496 .start = perf_swevent_start,
8497 .stop = perf_swevent_stop,
8498 .read = perf_swevent_read,
8501 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
8503 * Flags in config, used by dynamic PMU kprobe and uprobe
8504 * The flags should match following PMU_FORMAT_ATTR().
8506 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
8507 * if not set, create kprobe/uprobe
8509 enum perf_probe_config {
8510 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
8513 PMU_FORMAT_ATTR(retprobe, "config:0");
8515 static struct attribute *probe_attrs[] = {
8516 &format_attr_retprobe.attr,
8520 static struct attribute_group probe_format_group = {
8522 .attrs = probe_attrs,
8525 static const struct attribute_group *probe_attr_groups[] = {
8526 &probe_format_group,
8531 #ifdef CONFIG_KPROBE_EVENTS
8532 static int perf_kprobe_event_init(struct perf_event *event);
8533 static struct pmu perf_kprobe = {
8534 .task_ctx_nr = perf_sw_context,
8535 .event_init = perf_kprobe_event_init,
8536 .add = perf_trace_add,
8537 .del = perf_trace_del,
8538 .start = perf_swevent_start,
8539 .stop = perf_swevent_stop,
8540 .read = perf_swevent_read,
8541 .attr_groups = probe_attr_groups,
8544 static int perf_kprobe_event_init(struct perf_event *event)
8549 if (event->attr.type != perf_kprobe.type)
8552 if (!capable(CAP_SYS_ADMIN))
8556 * no branch sampling for probe events
8558 if (has_branch_stack(event))
8561 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8562 err = perf_kprobe_init(event, is_retprobe);
8566 event->destroy = perf_kprobe_destroy;
8570 #endif /* CONFIG_KPROBE_EVENTS */
8572 #ifdef CONFIG_UPROBE_EVENTS
8573 static int perf_uprobe_event_init(struct perf_event *event);
8574 static struct pmu perf_uprobe = {
8575 .task_ctx_nr = perf_sw_context,
8576 .event_init = perf_uprobe_event_init,
8577 .add = perf_trace_add,
8578 .del = perf_trace_del,
8579 .start = perf_swevent_start,
8580 .stop = perf_swevent_stop,
8581 .read = perf_swevent_read,
8582 .attr_groups = probe_attr_groups,
8585 static int perf_uprobe_event_init(struct perf_event *event)
8590 if (event->attr.type != perf_uprobe.type)
8593 if (!capable(CAP_SYS_ADMIN))
8597 * no branch sampling for probe events
8599 if (has_branch_stack(event))
8602 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8603 err = perf_uprobe_init(event, is_retprobe);
8607 event->destroy = perf_uprobe_destroy;
8611 #endif /* CONFIG_UPROBE_EVENTS */
8613 static inline void perf_tp_register(void)
8615 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8616 #ifdef CONFIG_KPROBE_EVENTS
8617 perf_pmu_register(&perf_kprobe, "kprobe", -1);
8619 #ifdef CONFIG_UPROBE_EVENTS
8620 perf_pmu_register(&perf_uprobe, "uprobe", -1);
8624 static void perf_event_free_filter(struct perf_event *event)
8626 ftrace_profile_free_filter(event);
8629 #ifdef CONFIG_BPF_SYSCALL
8630 static void bpf_overflow_handler(struct perf_event *event,
8631 struct perf_sample_data *data,
8632 struct pt_regs *regs)
8634 struct bpf_perf_event_data_kern ctx = {
8640 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
8642 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8645 ret = BPF_PROG_RUN(event->prog, &ctx);
8648 __this_cpu_dec(bpf_prog_active);
8653 event->orig_overflow_handler(event, data, regs);
8656 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8658 struct bpf_prog *prog;
8660 if (event->overflow_handler_context)
8661 /* hw breakpoint or kernel counter */
8667 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8669 return PTR_ERR(prog);
8672 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8673 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8677 static void perf_event_free_bpf_handler(struct perf_event *event)
8679 struct bpf_prog *prog = event->prog;
8684 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8689 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8693 static void perf_event_free_bpf_handler(struct perf_event *event)
8699 * returns true if the event is a tracepoint, or a kprobe/upprobe created
8700 * with perf_event_open()
8702 static inline bool perf_event_is_tracing(struct perf_event *event)
8704 if (event->pmu == &perf_tracepoint)
8706 #ifdef CONFIG_KPROBE_EVENTS
8707 if (event->pmu == &perf_kprobe)
8710 #ifdef CONFIG_UPROBE_EVENTS
8711 if (event->pmu == &perf_uprobe)
8717 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8719 bool is_kprobe, is_tracepoint, is_syscall_tp;
8720 struct bpf_prog *prog;
8723 if (!perf_event_is_tracing(event))
8724 return perf_event_set_bpf_handler(event, prog_fd);
8726 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8727 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8728 is_syscall_tp = is_syscall_trace_event(event->tp_event);
8729 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
8730 /* bpf programs can only be attached to u/kprobe or tracepoint */
8733 prog = bpf_prog_get(prog_fd);
8735 return PTR_ERR(prog);
8737 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8738 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
8739 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8740 /* valid fd, but invalid bpf program type */
8745 /* Kprobe override only works for kprobes, not uprobes. */
8746 if (prog->kprobe_override &&
8747 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
8752 if (is_tracepoint || is_syscall_tp) {
8753 int off = trace_event_get_offsets(event->tp_event);
8755 if (prog->aux->max_ctx_offset > off) {
8761 ret = perf_event_attach_bpf_prog(event, prog);
8767 static void perf_event_free_bpf_prog(struct perf_event *event)
8769 if (!perf_event_is_tracing(event)) {
8770 perf_event_free_bpf_handler(event);
8773 perf_event_detach_bpf_prog(event);
8778 static inline void perf_tp_register(void)
8782 static void perf_event_free_filter(struct perf_event *event)
8786 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8791 static void perf_event_free_bpf_prog(struct perf_event *event)
8794 #endif /* CONFIG_EVENT_TRACING */
8796 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8797 void perf_bp_event(struct perf_event *bp, void *data)
8799 struct perf_sample_data sample;
8800 struct pt_regs *regs = data;
8802 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8804 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8805 perf_swevent_event(bp, 1, &sample, regs);
8810 * Allocate a new address filter
8812 static struct perf_addr_filter *
8813 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8815 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8816 struct perf_addr_filter *filter;
8818 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8822 INIT_LIST_HEAD(&filter->entry);
8823 list_add_tail(&filter->entry, filters);
8828 static void free_filters_list(struct list_head *filters)
8830 struct perf_addr_filter *filter, *iter;
8832 list_for_each_entry_safe(filter, iter, filters, entry) {
8833 path_put(&filter->path);
8834 list_del(&filter->entry);
8840 * Free existing address filters and optionally install new ones
8842 static void perf_addr_filters_splice(struct perf_event *event,
8843 struct list_head *head)
8845 unsigned long flags;
8848 if (!has_addr_filter(event))
8851 /* don't bother with children, they don't have their own filters */
8855 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8857 list_splice_init(&event->addr_filters.list, &list);
8859 list_splice(head, &event->addr_filters.list);
8861 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8863 free_filters_list(&list);
8867 * Scan through mm's vmas and see if one of them matches the
8868 * @filter; if so, adjust filter's address range.
8869 * Called with mm::mmap_sem down for reading.
8871 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
8872 struct mm_struct *mm,
8873 struct perf_addr_filter_range *fr)
8875 struct vm_area_struct *vma;
8877 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8881 if (perf_addr_filter_vma_adjust(filter, vma, fr))
8887 * Update event's address range filters based on the
8888 * task's existing mappings, if any.
8890 static void perf_event_addr_filters_apply(struct perf_event *event)
8892 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8893 struct task_struct *task = READ_ONCE(event->ctx->task);
8894 struct perf_addr_filter *filter;
8895 struct mm_struct *mm = NULL;
8896 unsigned int count = 0;
8897 unsigned long flags;
8900 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8901 * will stop on the parent's child_mutex that our caller is also holding
8903 if (task == TASK_TOMBSTONE)
8906 if (ifh->nr_file_filters) {
8907 mm = get_task_mm(event->ctx->task);
8911 down_read(&mm->mmap_sem);
8914 raw_spin_lock_irqsave(&ifh->lock, flags);
8915 list_for_each_entry(filter, &ifh->list, entry) {
8916 if (filter->path.dentry) {
8918 * Adjust base offset if the filter is associated to a
8919 * binary that needs to be mapped:
8921 event->addr_filter_ranges[count].start = 0;
8922 event->addr_filter_ranges[count].size = 0;
8924 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
8926 event->addr_filter_ranges[count].start = filter->offset;
8927 event->addr_filter_ranges[count].size = filter->size;
8933 event->addr_filters_gen++;
8934 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8936 if (ifh->nr_file_filters) {
8937 up_read(&mm->mmap_sem);
8943 perf_event_stop(event, 1);
8947 * Address range filtering: limiting the data to certain
8948 * instruction address ranges. Filters are ioctl()ed to us from
8949 * userspace as ascii strings.
8951 * Filter string format:
8954 * where ACTION is one of the
8955 * * "filter": limit the trace to this region
8956 * * "start": start tracing from this address
8957 * * "stop": stop tracing at this address/region;
8959 * * for kernel addresses: <start address>[/<size>]
8960 * * for object files: <start address>[/<size>]@</path/to/object/file>
8962 * if <size> is not specified or is zero, the range is treated as a single
8963 * address; not valid for ACTION=="filter".
8977 IF_STATE_ACTION = 0,
8982 static const match_table_t if_tokens = {
8983 { IF_ACT_FILTER, "filter" },
8984 { IF_ACT_START, "start" },
8985 { IF_ACT_STOP, "stop" },
8986 { IF_SRC_FILE, "%u/%u@%s" },
8987 { IF_SRC_KERNEL, "%u/%u" },
8988 { IF_SRC_FILEADDR, "%u@%s" },
8989 { IF_SRC_KERNELADDR, "%u" },
8990 { IF_ACT_NONE, NULL },
8994 * Address filter string parser
8997 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8998 struct list_head *filters)
9000 struct perf_addr_filter *filter = NULL;
9001 char *start, *orig, *filename = NULL;
9002 substring_t args[MAX_OPT_ARGS];
9003 int state = IF_STATE_ACTION, token;
9004 unsigned int kernel = 0;
9007 orig = fstr = kstrdup(fstr, GFP_KERNEL);
9011 while ((start = strsep(&fstr, " ,\n")) != NULL) {
9012 static const enum perf_addr_filter_action_t actions[] = {
9013 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
9014 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
9015 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
9022 /* filter definition begins */
9023 if (state == IF_STATE_ACTION) {
9024 filter = perf_addr_filter_new(event, filters);
9029 token = match_token(start, if_tokens, args);
9034 if (state != IF_STATE_ACTION)
9037 filter->action = actions[token];
9038 state = IF_STATE_SOURCE;
9041 case IF_SRC_KERNELADDR:
9045 case IF_SRC_FILEADDR:
9047 if (state != IF_STATE_SOURCE)
9051 ret = kstrtoul(args[0].from, 0, &filter->offset);
9055 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
9057 ret = kstrtoul(args[1].from, 0, &filter->size);
9062 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9063 int fpos = token == IF_SRC_FILE ? 2 : 1;
9066 filename = match_strdup(&args[fpos]);
9073 state = IF_STATE_END;
9081 * Filter definition is fully parsed, validate and install it.
9082 * Make sure that it doesn't contradict itself or the event's
9085 if (state == IF_STATE_END) {
9087 if (kernel && event->attr.exclude_kernel)
9091 * ACTION "filter" must have a non-zero length region
9094 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9103 * For now, we only support file-based filters
9104 * in per-task events; doing so for CPU-wide
9105 * events requires additional context switching
9106 * trickery, since same object code will be
9107 * mapped at different virtual addresses in
9108 * different processes.
9111 if (!event->ctx->task)
9114 /* look up the path and grab its inode */
9115 ret = kern_path(filename, LOOKUP_FOLLOW,
9121 if (!filter->path.dentry ||
9122 !S_ISREG(d_inode(filter->path.dentry)
9126 event->addr_filters.nr_file_filters++;
9129 /* ready to consume more filters */
9130 state = IF_STATE_ACTION;
9135 if (state != IF_STATE_ACTION)
9145 free_filters_list(filters);
9152 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
9158 * Since this is called in perf_ioctl() path, we're already holding
9161 lockdep_assert_held(&event->ctx->mutex);
9163 if (WARN_ON_ONCE(event->parent))
9166 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
9168 goto fail_clear_files;
9170 ret = event->pmu->addr_filters_validate(&filters);
9172 goto fail_free_filters;
9174 /* remove existing filters, if any */
9175 perf_addr_filters_splice(event, &filters);
9177 /* install new filters */
9178 perf_event_for_each_child(event, perf_event_addr_filters_apply);
9183 free_filters_list(&filters);
9186 event->addr_filters.nr_file_filters = 0;
9191 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
9196 filter_str = strndup_user(arg, PAGE_SIZE);
9197 if (IS_ERR(filter_str))
9198 return PTR_ERR(filter_str);
9200 #ifdef CONFIG_EVENT_TRACING
9201 if (perf_event_is_tracing(event)) {
9202 struct perf_event_context *ctx = event->ctx;
9205 * Beware, here be dragons!!
9207 * the tracepoint muck will deadlock against ctx->mutex, but
9208 * the tracepoint stuff does not actually need it. So
9209 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
9210 * already have a reference on ctx.
9212 * This can result in event getting moved to a different ctx,
9213 * but that does not affect the tracepoint state.
9215 mutex_unlock(&ctx->mutex);
9216 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
9217 mutex_lock(&ctx->mutex);
9220 if (has_addr_filter(event))
9221 ret = perf_event_set_addr_filter(event, filter_str);
9228 * hrtimer based swevent callback
9231 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
9233 enum hrtimer_restart ret = HRTIMER_RESTART;
9234 struct perf_sample_data data;
9235 struct pt_regs *regs;
9236 struct perf_event *event;
9239 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
9241 if (event->state != PERF_EVENT_STATE_ACTIVE)
9242 return HRTIMER_NORESTART;
9244 event->pmu->read(event);
9246 perf_sample_data_init(&data, 0, event->hw.last_period);
9247 regs = get_irq_regs();
9249 if (regs && !perf_exclude_event(event, regs)) {
9250 if (!(event->attr.exclude_idle && is_idle_task(current)))
9251 if (__perf_event_overflow(event, 1, &data, regs))
9252 ret = HRTIMER_NORESTART;
9255 period = max_t(u64, 10000, event->hw.sample_period);
9256 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
9261 static void perf_swevent_start_hrtimer(struct perf_event *event)
9263 struct hw_perf_event *hwc = &event->hw;
9266 if (!is_sampling_event(event))
9269 period = local64_read(&hwc->period_left);
9274 local64_set(&hwc->period_left, 0);
9276 period = max_t(u64, 10000, hwc->sample_period);
9278 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
9279 HRTIMER_MODE_REL_PINNED);
9282 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
9284 struct hw_perf_event *hwc = &event->hw;
9286 if (is_sampling_event(event)) {
9287 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
9288 local64_set(&hwc->period_left, ktime_to_ns(remaining));
9290 hrtimer_cancel(&hwc->hrtimer);
9294 static void perf_swevent_init_hrtimer(struct perf_event *event)
9296 struct hw_perf_event *hwc = &event->hw;
9298 if (!is_sampling_event(event))
9301 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
9302 hwc->hrtimer.function = perf_swevent_hrtimer;
9305 * Since hrtimers have a fixed rate, we can do a static freq->period
9306 * mapping and avoid the whole period adjust feedback stuff.
9308 if (event->attr.freq) {
9309 long freq = event->attr.sample_freq;
9311 event->attr.sample_period = NSEC_PER_SEC / freq;
9312 hwc->sample_period = event->attr.sample_period;
9313 local64_set(&hwc->period_left, hwc->sample_period);
9314 hwc->last_period = hwc->sample_period;
9315 event->attr.freq = 0;
9320 * Software event: cpu wall time clock
9323 static void cpu_clock_event_update(struct perf_event *event)
9328 now = local_clock();
9329 prev = local64_xchg(&event->hw.prev_count, now);
9330 local64_add(now - prev, &event->count);
9333 static void cpu_clock_event_start(struct perf_event *event, int flags)
9335 local64_set(&event->hw.prev_count, local_clock());
9336 perf_swevent_start_hrtimer(event);
9339 static void cpu_clock_event_stop(struct perf_event *event, int flags)
9341 perf_swevent_cancel_hrtimer(event);
9342 cpu_clock_event_update(event);
9345 static int cpu_clock_event_add(struct perf_event *event, int flags)
9347 if (flags & PERF_EF_START)
9348 cpu_clock_event_start(event, flags);
9349 perf_event_update_userpage(event);
9354 static void cpu_clock_event_del(struct perf_event *event, int flags)
9356 cpu_clock_event_stop(event, flags);
9359 static void cpu_clock_event_read(struct perf_event *event)
9361 cpu_clock_event_update(event);
9364 static int cpu_clock_event_init(struct perf_event *event)
9366 if (event->attr.type != PERF_TYPE_SOFTWARE)
9369 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
9373 * no branch sampling for software events
9375 if (has_branch_stack(event))
9378 perf_swevent_init_hrtimer(event);
9383 static struct pmu perf_cpu_clock = {
9384 .task_ctx_nr = perf_sw_context,
9386 .capabilities = PERF_PMU_CAP_NO_NMI,
9388 .event_init = cpu_clock_event_init,
9389 .add = cpu_clock_event_add,
9390 .del = cpu_clock_event_del,
9391 .start = cpu_clock_event_start,
9392 .stop = cpu_clock_event_stop,
9393 .read = cpu_clock_event_read,
9397 * Software event: task time clock
9400 static void task_clock_event_update(struct perf_event *event, u64 now)
9405 prev = local64_xchg(&event->hw.prev_count, now);
9407 local64_add(delta, &event->count);
9410 static void task_clock_event_start(struct perf_event *event, int flags)
9412 local64_set(&event->hw.prev_count, event->ctx->time);
9413 perf_swevent_start_hrtimer(event);
9416 static void task_clock_event_stop(struct perf_event *event, int flags)
9418 perf_swevent_cancel_hrtimer(event);
9419 task_clock_event_update(event, event->ctx->time);
9422 static int task_clock_event_add(struct perf_event *event, int flags)
9424 if (flags & PERF_EF_START)
9425 task_clock_event_start(event, flags);
9426 perf_event_update_userpage(event);
9431 static void task_clock_event_del(struct perf_event *event, int flags)
9433 task_clock_event_stop(event, PERF_EF_UPDATE);
9436 static void task_clock_event_read(struct perf_event *event)
9438 u64 now = perf_clock();
9439 u64 delta = now - event->ctx->timestamp;
9440 u64 time = event->ctx->time + delta;
9442 task_clock_event_update(event, time);
9445 static int task_clock_event_init(struct perf_event *event)
9447 if (event->attr.type != PERF_TYPE_SOFTWARE)
9450 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
9454 * no branch sampling for software events
9456 if (has_branch_stack(event))
9459 perf_swevent_init_hrtimer(event);
9464 static struct pmu perf_task_clock = {
9465 .task_ctx_nr = perf_sw_context,
9467 .capabilities = PERF_PMU_CAP_NO_NMI,
9469 .event_init = task_clock_event_init,
9470 .add = task_clock_event_add,
9471 .del = task_clock_event_del,
9472 .start = task_clock_event_start,
9473 .stop = task_clock_event_stop,
9474 .read = task_clock_event_read,
9477 static void perf_pmu_nop_void(struct pmu *pmu)
9481 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
9485 static int perf_pmu_nop_int(struct pmu *pmu)
9490 static int perf_event_nop_int(struct perf_event *event, u64 value)
9495 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
9497 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
9499 __this_cpu_write(nop_txn_flags, flags);
9501 if (flags & ~PERF_PMU_TXN_ADD)
9504 perf_pmu_disable(pmu);
9507 static int perf_pmu_commit_txn(struct pmu *pmu)
9509 unsigned int flags = __this_cpu_read(nop_txn_flags);
9511 __this_cpu_write(nop_txn_flags, 0);
9513 if (flags & ~PERF_PMU_TXN_ADD)
9516 perf_pmu_enable(pmu);
9520 static void perf_pmu_cancel_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);
9532 static int perf_event_idx_default(struct perf_event *event)
9538 * Ensures all contexts with the same task_ctx_nr have the same
9539 * pmu_cpu_context too.
9541 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
9548 list_for_each_entry(pmu, &pmus, entry) {
9549 if (pmu->task_ctx_nr == ctxn)
9550 return pmu->pmu_cpu_context;
9556 static void free_pmu_context(struct pmu *pmu)
9559 * Static contexts such as perf_sw_context have a global lifetime
9560 * and may be shared between different PMUs. Avoid freeing them
9561 * when a single PMU is going away.
9563 if (pmu->task_ctx_nr > perf_invalid_context)
9566 free_percpu(pmu->pmu_cpu_context);
9570 * Let userspace know that this PMU supports address range filtering:
9572 static ssize_t nr_addr_filters_show(struct device *dev,
9573 struct device_attribute *attr,
9576 struct pmu *pmu = dev_get_drvdata(dev);
9578 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
9580 DEVICE_ATTR_RO(nr_addr_filters);
9582 static struct idr pmu_idr;
9585 type_show(struct device *dev, struct device_attribute *attr, char *page)
9587 struct pmu *pmu = dev_get_drvdata(dev);
9589 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
9591 static DEVICE_ATTR_RO(type);
9594 perf_event_mux_interval_ms_show(struct device *dev,
9595 struct device_attribute *attr,
9598 struct pmu *pmu = dev_get_drvdata(dev);
9600 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9603 static DEFINE_MUTEX(mux_interval_mutex);
9606 perf_event_mux_interval_ms_store(struct device *dev,
9607 struct device_attribute *attr,
9608 const char *buf, size_t count)
9610 struct pmu *pmu = dev_get_drvdata(dev);
9611 int timer, cpu, ret;
9613 ret = kstrtoint(buf, 0, &timer);
9620 /* same value, noting to do */
9621 if (timer == pmu->hrtimer_interval_ms)
9624 mutex_lock(&mux_interval_mutex);
9625 pmu->hrtimer_interval_ms = timer;
9627 /* update all cpuctx for this PMU */
9629 for_each_online_cpu(cpu) {
9630 struct perf_cpu_context *cpuctx;
9631 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9632 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9634 cpu_function_call(cpu,
9635 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
9638 mutex_unlock(&mux_interval_mutex);
9642 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9644 static struct attribute *pmu_dev_attrs[] = {
9645 &dev_attr_type.attr,
9646 &dev_attr_perf_event_mux_interval_ms.attr,
9649 ATTRIBUTE_GROUPS(pmu_dev);
9651 static int pmu_bus_running;
9652 static struct bus_type pmu_bus = {
9653 .name = "event_source",
9654 .dev_groups = pmu_dev_groups,
9657 static void pmu_dev_release(struct device *dev)
9662 static int pmu_dev_alloc(struct pmu *pmu)
9666 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9670 pmu->dev->groups = pmu->attr_groups;
9671 device_initialize(pmu->dev);
9672 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9676 dev_set_drvdata(pmu->dev, pmu);
9677 pmu->dev->bus = &pmu_bus;
9678 pmu->dev->release = pmu_dev_release;
9679 ret = device_add(pmu->dev);
9683 /* For PMUs with address filters, throw in an extra attribute: */
9684 if (pmu->nr_addr_filters)
9685 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9694 device_del(pmu->dev);
9697 put_device(pmu->dev);
9701 static struct lock_class_key cpuctx_mutex;
9702 static struct lock_class_key cpuctx_lock;
9704 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9708 mutex_lock(&pmus_lock);
9710 pmu->pmu_disable_count = alloc_percpu(int);
9711 if (!pmu->pmu_disable_count)
9720 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9728 if (pmu_bus_running) {
9729 ret = pmu_dev_alloc(pmu);
9735 if (pmu->task_ctx_nr == perf_hw_context) {
9736 static int hw_context_taken = 0;
9739 * Other than systems with heterogeneous CPUs, it never makes
9740 * sense for two PMUs to share perf_hw_context. PMUs which are
9741 * uncore must use perf_invalid_context.
9743 if (WARN_ON_ONCE(hw_context_taken &&
9744 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9745 pmu->task_ctx_nr = perf_invalid_context;
9747 hw_context_taken = 1;
9750 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9751 if (pmu->pmu_cpu_context)
9752 goto got_cpu_context;
9755 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9756 if (!pmu->pmu_cpu_context)
9759 for_each_possible_cpu(cpu) {
9760 struct perf_cpu_context *cpuctx;
9762 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9763 __perf_event_init_context(&cpuctx->ctx);
9764 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9765 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9766 cpuctx->ctx.pmu = pmu;
9767 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9769 __perf_mux_hrtimer_init(cpuctx, cpu);
9773 if (!pmu->start_txn) {
9774 if (pmu->pmu_enable) {
9776 * If we have pmu_enable/pmu_disable calls, install
9777 * transaction stubs that use that to try and batch
9778 * hardware accesses.
9780 pmu->start_txn = perf_pmu_start_txn;
9781 pmu->commit_txn = perf_pmu_commit_txn;
9782 pmu->cancel_txn = perf_pmu_cancel_txn;
9784 pmu->start_txn = perf_pmu_nop_txn;
9785 pmu->commit_txn = perf_pmu_nop_int;
9786 pmu->cancel_txn = perf_pmu_nop_void;
9790 if (!pmu->pmu_enable) {
9791 pmu->pmu_enable = perf_pmu_nop_void;
9792 pmu->pmu_disable = perf_pmu_nop_void;
9795 if (!pmu->check_period)
9796 pmu->check_period = perf_event_nop_int;
9798 if (!pmu->event_idx)
9799 pmu->event_idx = perf_event_idx_default;
9801 list_add_rcu(&pmu->entry, &pmus);
9802 atomic_set(&pmu->exclusive_cnt, 0);
9805 mutex_unlock(&pmus_lock);
9810 device_del(pmu->dev);
9811 put_device(pmu->dev);
9814 if (pmu->type >= PERF_TYPE_MAX)
9815 idr_remove(&pmu_idr, pmu->type);
9818 free_percpu(pmu->pmu_disable_count);
9821 EXPORT_SYMBOL_GPL(perf_pmu_register);
9823 void perf_pmu_unregister(struct pmu *pmu)
9825 mutex_lock(&pmus_lock);
9826 list_del_rcu(&pmu->entry);
9829 * We dereference the pmu list under both SRCU and regular RCU, so
9830 * synchronize against both of those.
9832 synchronize_srcu(&pmus_srcu);
9835 free_percpu(pmu->pmu_disable_count);
9836 if (pmu->type >= PERF_TYPE_MAX)
9837 idr_remove(&pmu_idr, pmu->type);
9838 if (pmu_bus_running) {
9839 if (pmu->nr_addr_filters)
9840 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9841 device_del(pmu->dev);
9842 put_device(pmu->dev);
9844 free_pmu_context(pmu);
9845 mutex_unlock(&pmus_lock);
9847 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9849 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9851 struct perf_event_context *ctx = NULL;
9854 if (!try_module_get(pmu->module))
9858 * A number of pmu->event_init() methods iterate the sibling_list to,
9859 * for example, validate if the group fits on the PMU. Therefore,
9860 * if this is a sibling event, acquire the ctx->mutex to protect
9863 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
9865 * This ctx->mutex can nest when we're called through
9866 * inheritance. See the perf_event_ctx_lock_nested() comment.
9868 ctx = perf_event_ctx_lock_nested(event->group_leader,
9869 SINGLE_DEPTH_NESTING);
9874 ret = pmu->event_init(event);
9877 perf_event_ctx_unlock(event->group_leader, ctx);
9880 module_put(pmu->module);
9885 static struct pmu *perf_init_event(struct perf_event *event)
9891 idx = srcu_read_lock(&pmus_srcu);
9893 /* Try parent's PMU first: */
9894 if (event->parent && event->parent->pmu) {
9895 pmu = event->parent->pmu;
9896 ret = perf_try_init_event(pmu, event);
9902 pmu = idr_find(&pmu_idr, event->attr.type);
9905 ret = perf_try_init_event(pmu, event);
9911 list_for_each_entry_rcu(pmu, &pmus, entry) {
9912 ret = perf_try_init_event(pmu, event);
9916 if (ret != -ENOENT) {
9921 pmu = ERR_PTR(-ENOENT);
9923 srcu_read_unlock(&pmus_srcu, idx);
9928 static void attach_sb_event(struct perf_event *event)
9930 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9932 raw_spin_lock(&pel->lock);
9933 list_add_rcu(&event->sb_list, &pel->list);
9934 raw_spin_unlock(&pel->lock);
9938 * We keep a list of all !task (and therefore per-cpu) events
9939 * that need to receive side-band records.
9941 * This avoids having to scan all the various PMU per-cpu contexts
9944 static void account_pmu_sb_event(struct perf_event *event)
9946 if (is_sb_event(event))
9947 attach_sb_event(event);
9950 static void account_event_cpu(struct perf_event *event, int cpu)
9955 if (is_cgroup_event(event))
9956 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9959 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9960 static void account_freq_event_nohz(void)
9962 #ifdef CONFIG_NO_HZ_FULL
9963 /* Lock so we don't race with concurrent unaccount */
9964 spin_lock(&nr_freq_lock);
9965 if (atomic_inc_return(&nr_freq_events) == 1)
9966 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9967 spin_unlock(&nr_freq_lock);
9971 static void account_freq_event(void)
9973 if (tick_nohz_full_enabled())
9974 account_freq_event_nohz();
9976 atomic_inc(&nr_freq_events);
9980 static void account_event(struct perf_event *event)
9987 if (event->attach_state & PERF_ATTACH_TASK)
9989 if (event->attr.mmap || event->attr.mmap_data)
9990 atomic_inc(&nr_mmap_events);
9991 if (event->attr.comm)
9992 atomic_inc(&nr_comm_events);
9993 if (event->attr.namespaces)
9994 atomic_inc(&nr_namespaces_events);
9995 if (event->attr.task)
9996 atomic_inc(&nr_task_events);
9997 if (event->attr.freq)
9998 account_freq_event();
9999 if (event->attr.context_switch) {
10000 atomic_inc(&nr_switch_events);
10003 if (has_branch_stack(event))
10005 if (is_cgroup_event(event))
10010 * We need the mutex here because static_branch_enable()
10011 * must complete *before* the perf_sched_count increment
10014 if (atomic_inc_not_zero(&perf_sched_count))
10017 mutex_lock(&perf_sched_mutex);
10018 if (!atomic_read(&perf_sched_count)) {
10019 static_branch_enable(&perf_sched_events);
10021 * Guarantee that all CPUs observe they key change and
10022 * call the perf scheduling hooks before proceeding to
10023 * install events that need them.
10025 synchronize_sched();
10028 * Now that we have waited for the sync_sched(), allow further
10029 * increments to by-pass the mutex.
10031 atomic_inc(&perf_sched_count);
10032 mutex_unlock(&perf_sched_mutex);
10036 account_event_cpu(event, event->cpu);
10038 account_pmu_sb_event(event);
10042 * Allocate and initialize an event structure
10044 static struct perf_event *
10045 perf_event_alloc(struct perf_event_attr *attr, int cpu,
10046 struct task_struct *task,
10047 struct perf_event *group_leader,
10048 struct perf_event *parent_event,
10049 perf_overflow_handler_t overflow_handler,
10050 void *context, int cgroup_fd)
10053 struct perf_event *event;
10054 struct hw_perf_event *hwc;
10055 long err = -EINVAL;
10057 if ((unsigned)cpu >= nr_cpu_ids) {
10058 if (!task || cpu != -1)
10059 return ERR_PTR(-EINVAL);
10062 event = kzalloc(sizeof(*event), GFP_KERNEL);
10064 return ERR_PTR(-ENOMEM);
10067 * Single events are their own group leaders, with an
10068 * empty sibling list:
10071 group_leader = event;
10073 mutex_init(&event->child_mutex);
10074 INIT_LIST_HEAD(&event->child_list);
10076 INIT_LIST_HEAD(&event->event_entry);
10077 INIT_LIST_HEAD(&event->sibling_list);
10078 INIT_LIST_HEAD(&event->active_list);
10079 init_event_group(event);
10080 INIT_LIST_HEAD(&event->rb_entry);
10081 INIT_LIST_HEAD(&event->active_entry);
10082 INIT_LIST_HEAD(&event->addr_filters.list);
10083 INIT_HLIST_NODE(&event->hlist_entry);
10086 init_waitqueue_head(&event->waitq);
10087 event->pending_disable = -1;
10088 init_irq_work(&event->pending, perf_pending_event);
10090 mutex_init(&event->mmap_mutex);
10091 raw_spin_lock_init(&event->addr_filters.lock);
10093 atomic_long_set(&event->refcount, 1);
10095 event->attr = *attr;
10096 event->group_leader = group_leader;
10100 event->parent = parent_event;
10102 event->ns = get_pid_ns(task_active_pid_ns(current));
10103 event->id = atomic64_inc_return(&perf_event_id);
10105 event->state = PERF_EVENT_STATE_INACTIVE;
10108 event->attach_state = PERF_ATTACH_TASK;
10110 * XXX pmu::event_init needs to know what task to account to
10111 * and we cannot use the ctx information because we need the
10112 * pmu before we get a ctx.
10114 get_task_struct(task);
10115 event->hw.target = task;
10118 event->clock = &local_clock;
10120 event->clock = parent_event->clock;
10122 if (!overflow_handler && parent_event) {
10123 overflow_handler = parent_event->overflow_handler;
10124 context = parent_event->overflow_handler_context;
10125 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
10126 if (overflow_handler == bpf_overflow_handler) {
10127 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
10129 if (IS_ERR(prog)) {
10130 err = PTR_ERR(prog);
10133 event->prog = prog;
10134 event->orig_overflow_handler =
10135 parent_event->orig_overflow_handler;
10140 if (overflow_handler) {
10141 event->overflow_handler = overflow_handler;
10142 event->overflow_handler_context = context;
10143 } else if (is_write_backward(event)){
10144 event->overflow_handler = perf_event_output_backward;
10145 event->overflow_handler_context = NULL;
10147 event->overflow_handler = perf_event_output_forward;
10148 event->overflow_handler_context = NULL;
10151 perf_event__state_init(event);
10156 hwc->sample_period = attr->sample_period;
10157 if (attr->freq && attr->sample_freq)
10158 hwc->sample_period = 1;
10159 hwc->last_period = hwc->sample_period;
10161 local64_set(&hwc->period_left, hwc->sample_period);
10164 * We currently do not support PERF_SAMPLE_READ on inherited events.
10165 * See perf_output_read().
10167 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
10170 if (!has_branch_stack(event))
10171 event->attr.branch_sample_type = 0;
10173 if (cgroup_fd != -1) {
10174 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
10179 pmu = perf_init_event(event);
10181 err = PTR_ERR(pmu);
10185 err = exclusive_event_init(event);
10189 if (has_addr_filter(event)) {
10190 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
10191 sizeof(struct perf_addr_filter_range),
10193 if (!event->addr_filter_ranges) {
10199 * Clone the parent's vma offsets: they are valid until exec()
10200 * even if the mm is not shared with the parent.
10202 if (event->parent) {
10203 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10205 raw_spin_lock_irq(&ifh->lock);
10206 memcpy(event->addr_filter_ranges,
10207 event->parent->addr_filter_ranges,
10208 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
10209 raw_spin_unlock_irq(&ifh->lock);
10212 /* force hw sync on the address filters */
10213 event->addr_filters_gen = 1;
10216 if (!event->parent) {
10217 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
10218 err = get_callchain_buffers(attr->sample_max_stack);
10220 goto err_addr_filters;
10224 /* symmetric to unaccount_event() in _free_event() */
10225 account_event(event);
10230 kfree(event->addr_filter_ranges);
10233 exclusive_event_destroy(event);
10236 if (event->destroy)
10237 event->destroy(event);
10238 module_put(pmu->module);
10240 if (is_cgroup_event(event))
10241 perf_detach_cgroup(event);
10243 put_pid_ns(event->ns);
10244 if (event->hw.target)
10245 put_task_struct(event->hw.target);
10248 return ERR_PTR(err);
10251 static int perf_copy_attr(struct perf_event_attr __user *uattr,
10252 struct perf_event_attr *attr)
10257 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
10261 * zero the full structure, so that a short copy will be nice.
10263 memset(attr, 0, sizeof(*attr));
10265 ret = get_user(size, &uattr->size);
10269 if (size > PAGE_SIZE) /* silly large */
10272 if (!size) /* abi compat */
10273 size = PERF_ATTR_SIZE_VER0;
10275 if (size < PERF_ATTR_SIZE_VER0)
10279 * If we're handed a bigger struct than we know of,
10280 * ensure all the unknown bits are 0 - i.e. new
10281 * user-space does not rely on any kernel feature
10282 * extensions we dont know about yet.
10284 if (size > sizeof(*attr)) {
10285 unsigned char __user *addr;
10286 unsigned char __user *end;
10289 addr = (void __user *)uattr + sizeof(*attr);
10290 end = (void __user *)uattr + size;
10292 for (; addr < end; addr++) {
10293 ret = get_user(val, addr);
10299 size = sizeof(*attr);
10302 ret = copy_from_user(attr, uattr, size);
10308 if (attr->__reserved_1)
10311 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
10314 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
10317 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
10318 u64 mask = attr->branch_sample_type;
10320 /* only using defined bits */
10321 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
10324 /* at least one branch bit must be set */
10325 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
10328 /* propagate priv level, when not set for branch */
10329 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
10331 /* exclude_kernel checked on syscall entry */
10332 if (!attr->exclude_kernel)
10333 mask |= PERF_SAMPLE_BRANCH_KERNEL;
10335 if (!attr->exclude_user)
10336 mask |= PERF_SAMPLE_BRANCH_USER;
10338 if (!attr->exclude_hv)
10339 mask |= PERF_SAMPLE_BRANCH_HV;
10341 * adjust user setting (for HW filter setup)
10343 attr->branch_sample_type = mask;
10345 /* privileged levels capture (kernel, hv): check permissions */
10346 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
10347 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10351 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
10352 ret = perf_reg_validate(attr->sample_regs_user);
10357 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
10358 if (!arch_perf_have_user_stack_dump())
10362 * We have __u32 type for the size, but so far
10363 * we can only use __u16 as maximum due to the
10364 * __u16 sample size limit.
10366 if (attr->sample_stack_user >= USHRT_MAX)
10368 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
10372 if (!attr->sample_max_stack)
10373 attr->sample_max_stack = sysctl_perf_event_max_stack;
10375 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
10376 ret = perf_reg_validate(attr->sample_regs_intr);
10381 put_user(sizeof(*attr), &uattr->size);
10387 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
10389 struct ring_buffer *rb = NULL;
10395 /* don't allow circular references */
10396 if (event == output_event)
10400 * Don't allow cross-cpu buffers
10402 if (output_event->cpu != event->cpu)
10406 * If its not a per-cpu rb, it must be the same task.
10408 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
10412 * Mixing clocks in the same buffer is trouble you don't need.
10414 if (output_event->clock != event->clock)
10418 * Either writing ring buffer from beginning or from end.
10419 * Mixing is not allowed.
10421 if (is_write_backward(output_event) != is_write_backward(event))
10425 * If both events generate aux data, they must be on the same PMU
10427 if (has_aux(event) && has_aux(output_event) &&
10428 event->pmu != output_event->pmu)
10432 mutex_lock(&event->mmap_mutex);
10433 /* Can't redirect output if we've got an active mmap() */
10434 if (atomic_read(&event->mmap_count))
10437 if (output_event) {
10438 /* get the rb we want to redirect to */
10439 rb = ring_buffer_get(output_event);
10444 ring_buffer_attach(event, rb);
10448 mutex_unlock(&event->mmap_mutex);
10454 static void mutex_lock_double(struct mutex *a, struct mutex *b)
10460 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
10463 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
10465 bool nmi_safe = false;
10468 case CLOCK_MONOTONIC:
10469 event->clock = &ktime_get_mono_fast_ns;
10473 case CLOCK_MONOTONIC_RAW:
10474 event->clock = &ktime_get_raw_fast_ns;
10478 case CLOCK_REALTIME:
10479 event->clock = &ktime_get_real_ns;
10482 case CLOCK_BOOTTIME:
10483 event->clock = &ktime_get_boot_ns;
10487 event->clock = &ktime_get_tai_ns;
10494 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
10501 * Variation on perf_event_ctx_lock_nested(), except we take two context
10504 static struct perf_event_context *
10505 __perf_event_ctx_lock_double(struct perf_event *group_leader,
10506 struct perf_event_context *ctx)
10508 struct perf_event_context *gctx;
10512 gctx = READ_ONCE(group_leader->ctx);
10513 if (!atomic_inc_not_zero(&gctx->refcount)) {
10519 mutex_lock_double(&gctx->mutex, &ctx->mutex);
10521 if (group_leader->ctx != gctx) {
10522 mutex_unlock(&ctx->mutex);
10523 mutex_unlock(&gctx->mutex);
10532 * sys_perf_event_open - open a performance event, associate it to a task/cpu
10534 * @attr_uptr: event_id type attributes for monitoring/sampling
10537 * @group_fd: group leader event fd
10539 SYSCALL_DEFINE5(perf_event_open,
10540 struct perf_event_attr __user *, attr_uptr,
10541 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
10543 struct perf_event *group_leader = NULL, *output_event = NULL;
10544 struct perf_event *event, *sibling;
10545 struct perf_event_attr attr;
10546 struct perf_event_context *ctx, *uninitialized_var(gctx);
10547 struct file *event_file = NULL;
10548 struct fd group = {NULL, 0};
10549 struct task_struct *task = NULL;
10552 int move_group = 0;
10554 int f_flags = O_RDWR;
10555 int cgroup_fd = -1;
10557 /* for future expandability... */
10558 if (flags & ~PERF_FLAG_ALL)
10561 err = perf_copy_attr(attr_uptr, &attr);
10565 if (!attr.exclude_kernel) {
10566 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10570 if (attr.namespaces) {
10571 if (!capable(CAP_SYS_ADMIN))
10576 if (attr.sample_freq > sysctl_perf_event_sample_rate)
10579 if (attr.sample_period & (1ULL << 63))
10583 /* Only privileged users can get physical addresses */
10584 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
10585 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10589 * In cgroup mode, the pid argument is used to pass the fd
10590 * opened to the cgroup directory in cgroupfs. The cpu argument
10591 * designates the cpu on which to monitor threads from that
10594 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
10597 if (flags & PERF_FLAG_FD_CLOEXEC)
10598 f_flags |= O_CLOEXEC;
10600 event_fd = get_unused_fd_flags(f_flags);
10604 if (group_fd != -1) {
10605 err = perf_fget_light(group_fd, &group);
10608 group_leader = group.file->private_data;
10609 if (flags & PERF_FLAG_FD_OUTPUT)
10610 output_event = group_leader;
10611 if (flags & PERF_FLAG_FD_NO_GROUP)
10612 group_leader = NULL;
10615 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
10616 task = find_lively_task_by_vpid(pid);
10617 if (IS_ERR(task)) {
10618 err = PTR_ERR(task);
10623 if (task && group_leader &&
10624 group_leader->attr.inherit != attr.inherit) {
10630 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
10635 * Reuse ptrace permission checks for now.
10637 * We must hold cred_guard_mutex across this and any potential
10638 * perf_install_in_context() call for this new event to
10639 * serialize against exec() altering our credentials (and the
10640 * perf_event_exit_task() that could imply).
10643 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
10647 if (flags & PERF_FLAG_PID_CGROUP)
10650 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10651 NULL, NULL, cgroup_fd);
10652 if (IS_ERR(event)) {
10653 err = PTR_ERR(event);
10657 if (is_sampling_event(event)) {
10658 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
10665 * Special case software events and allow them to be part of
10666 * any hardware group.
10670 if (attr.use_clockid) {
10671 err = perf_event_set_clock(event, attr.clockid);
10676 if (pmu->task_ctx_nr == perf_sw_context)
10677 event->event_caps |= PERF_EV_CAP_SOFTWARE;
10679 if (group_leader) {
10680 if (is_software_event(event) &&
10681 !in_software_context(group_leader)) {
10683 * If the event is a sw event, but the group_leader
10684 * is on hw context.
10686 * Allow the addition of software events to hw
10687 * groups, this is safe because software events
10688 * never fail to schedule.
10690 pmu = group_leader->ctx->pmu;
10691 } else if (!is_software_event(event) &&
10692 is_software_event(group_leader) &&
10693 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10695 * In case the group is a pure software group, and we
10696 * try to add a hardware event, move the whole group to
10697 * the hardware context.
10704 * Get the target context (task or percpu):
10706 ctx = find_get_context(pmu, task, event);
10708 err = PTR_ERR(ctx);
10713 * Look up the group leader (we will attach this event to it):
10715 if (group_leader) {
10719 * Do not allow a recursive hierarchy (this new sibling
10720 * becoming part of another group-sibling):
10722 if (group_leader->group_leader != group_leader)
10725 /* All events in a group should have the same clock */
10726 if (group_leader->clock != event->clock)
10730 * Make sure we're both events for the same CPU;
10731 * grouping events for different CPUs is broken; since
10732 * you can never concurrently schedule them anyhow.
10734 if (group_leader->cpu != event->cpu)
10738 * Make sure we're both on the same task, or both
10741 if (group_leader->ctx->task != ctx->task)
10745 * Do not allow to attach to a group in a different task
10746 * or CPU context. If we're moving SW events, we'll fix
10747 * this up later, so allow that.
10749 if (!move_group && group_leader->ctx != ctx)
10753 * Only a group leader can be exclusive or pinned
10755 if (attr.exclusive || attr.pinned)
10759 if (output_event) {
10760 err = perf_event_set_output(event, output_event);
10765 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10767 if (IS_ERR(event_file)) {
10768 err = PTR_ERR(event_file);
10774 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10776 if (gctx->task == TASK_TOMBSTONE) {
10782 * Check if we raced against another sys_perf_event_open() call
10783 * moving the software group underneath us.
10785 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10787 * If someone moved the group out from under us, check
10788 * if this new event wound up on the same ctx, if so
10789 * its the regular !move_group case, otherwise fail.
10795 perf_event_ctx_unlock(group_leader, gctx);
10801 * Failure to create exclusive events returns -EBUSY.
10804 if (!exclusive_event_installable(group_leader, ctx))
10807 for_each_sibling_event(sibling, group_leader) {
10808 if (!exclusive_event_installable(sibling, ctx))
10812 mutex_lock(&ctx->mutex);
10815 if (ctx->task == TASK_TOMBSTONE) {
10820 if (!perf_event_validate_size(event)) {
10827 * Check if the @cpu we're creating an event for is online.
10829 * We use the perf_cpu_context::ctx::mutex to serialize against
10830 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10832 struct perf_cpu_context *cpuctx =
10833 container_of(ctx, struct perf_cpu_context, ctx);
10835 if (!cpuctx->online) {
10843 * Must be under the same ctx::mutex as perf_install_in_context(),
10844 * because we need to serialize with concurrent event creation.
10846 if (!exclusive_event_installable(event, ctx)) {
10851 WARN_ON_ONCE(ctx->parent_ctx);
10854 * This is the point on no return; we cannot fail hereafter. This is
10855 * where we start modifying current state.
10860 * See perf_event_ctx_lock() for comments on the details
10861 * of swizzling perf_event::ctx.
10863 perf_remove_from_context(group_leader, 0);
10866 for_each_sibling_event(sibling, group_leader) {
10867 perf_remove_from_context(sibling, 0);
10872 * Wait for everybody to stop referencing the events through
10873 * the old lists, before installing it on new lists.
10878 * Install the group siblings before the group leader.
10880 * Because a group leader will try and install the entire group
10881 * (through the sibling list, which is still in-tact), we can
10882 * end up with siblings installed in the wrong context.
10884 * By installing siblings first we NO-OP because they're not
10885 * reachable through the group lists.
10887 for_each_sibling_event(sibling, group_leader) {
10888 perf_event__state_init(sibling);
10889 perf_install_in_context(ctx, sibling, sibling->cpu);
10894 * Removing from the context ends up with disabled
10895 * event. What we want here is event in the initial
10896 * startup state, ready to be add into new context.
10898 perf_event__state_init(group_leader);
10899 perf_install_in_context(ctx, group_leader, group_leader->cpu);
10904 * Precalculate sample_data sizes; do while holding ctx::mutex such
10905 * that we're serialized against further additions and before
10906 * perf_install_in_context() which is the point the event is active and
10907 * can use these values.
10909 perf_event__header_size(event);
10910 perf_event__id_header_size(event);
10912 event->owner = current;
10914 perf_install_in_context(ctx, event, event->cpu);
10915 perf_unpin_context(ctx);
10918 perf_event_ctx_unlock(group_leader, gctx);
10919 mutex_unlock(&ctx->mutex);
10922 mutex_unlock(&task->signal->cred_guard_mutex);
10923 put_task_struct(task);
10926 mutex_lock(¤t->perf_event_mutex);
10927 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10928 mutex_unlock(¤t->perf_event_mutex);
10931 * Drop the reference on the group_event after placing the
10932 * new event on the sibling_list. This ensures destruction
10933 * of the group leader will find the pointer to itself in
10934 * perf_group_detach().
10937 fd_install(event_fd, event_file);
10942 perf_event_ctx_unlock(group_leader, gctx);
10943 mutex_unlock(&ctx->mutex);
10947 perf_unpin_context(ctx);
10951 * If event_file is set, the fput() above will have called ->release()
10952 * and that will take care of freeing the event.
10958 mutex_unlock(&task->signal->cred_guard_mutex);
10961 put_task_struct(task);
10965 put_unused_fd(event_fd);
10970 * perf_event_create_kernel_counter
10972 * @attr: attributes of the counter to create
10973 * @cpu: cpu in which the counter is bound
10974 * @task: task to profile (NULL for percpu)
10976 struct perf_event *
10977 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10978 struct task_struct *task,
10979 perf_overflow_handler_t overflow_handler,
10982 struct perf_event_context *ctx;
10983 struct perf_event *event;
10987 * Get the target context (task or percpu):
10990 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10991 overflow_handler, context, -1);
10992 if (IS_ERR(event)) {
10993 err = PTR_ERR(event);
10997 /* Mark owner so we could distinguish it from user events. */
10998 event->owner = TASK_TOMBSTONE;
11000 ctx = find_get_context(event->pmu, task, event);
11002 err = PTR_ERR(ctx);
11006 WARN_ON_ONCE(ctx->parent_ctx);
11007 mutex_lock(&ctx->mutex);
11008 if (ctx->task == TASK_TOMBSTONE) {
11015 * Check if the @cpu we're creating an event for is online.
11017 * We use the perf_cpu_context::ctx::mutex to serialize against
11018 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11020 struct perf_cpu_context *cpuctx =
11021 container_of(ctx, struct perf_cpu_context, ctx);
11022 if (!cpuctx->online) {
11028 if (!exclusive_event_installable(event, ctx)) {
11033 perf_install_in_context(ctx, event, event->cpu);
11034 perf_unpin_context(ctx);
11035 mutex_unlock(&ctx->mutex);
11040 mutex_unlock(&ctx->mutex);
11041 perf_unpin_context(ctx);
11046 return ERR_PTR(err);
11048 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
11050 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
11052 struct perf_event_context *src_ctx;
11053 struct perf_event_context *dst_ctx;
11054 struct perf_event *event, *tmp;
11057 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
11058 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
11061 * See perf_event_ctx_lock() for comments on the details
11062 * of swizzling perf_event::ctx.
11064 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
11065 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
11067 perf_remove_from_context(event, 0);
11068 unaccount_event_cpu(event, src_cpu);
11070 list_add(&event->migrate_entry, &events);
11074 * Wait for the events to quiesce before re-instating them.
11079 * Re-instate events in 2 passes.
11081 * Skip over group leaders and only install siblings on this first
11082 * pass, siblings will not get enabled without a leader, however a
11083 * leader will enable its siblings, even if those are still on the old
11086 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11087 if (event->group_leader == event)
11090 list_del(&event->migrate_entry);
11091 if (event->state >= PERF_EVENT_STATE_OFF)
11092 event->state = PERF_EVENT_STATE_INACTIVE;
11093 account_event_cpu(event, dst_cpu);
11094 perf_install_in_context(dst_ctx, event, dst_cpu);
11099 * Once all the siblings are setup properly, install the group leaders
11102 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
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);
11110 mutex_unlock(&dst_ctx->mutex);
11111 mutex_unlock(&src_ctx->mutex);
11113 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
11115 static void sync_child_event(struct perf_event *child_event,
11116 struct task_struct *child)
11118 struct perf_event *parent_event = child_event->parent;
11121 if (child_event->attr.inherit_stat)
11122 perf_event_read_event(child_event, child);
11124 child_val = perf_event_count(child_event);
11127 * Add back the child's count to the parent's count:
11129 atomic64_add(child_val, &parent_event->child_count);
11130 atomic64_add(child_event->total_time_enabled,
11131 &parent_event->child_total_time_enabled);
11132 atomic64_add(child_event->total_time_running,
11133 &parent_event->child_total_time_running);
11137 perf_event_exit_event(struct perf_event *child_event,
11138 struct perf_event_context *child_ctx,
11139 struct task_struct *child)
11141 struct perf_event *parent_event = child_event->parent;
11144 * Do not destroy the 'original' grouping; because of the context
11145 * switch optimization the original events could've ended up in a
11146 * random child task.
11148 * If we were to destroy the original group, all group related
11149 * operations would cease to function properly after this random
11152 * Do destroy all inherited groups, we don't care about those
11153 * and being thorough is better.
11155 raw_spin_lock_irq(&child_ctx->lock);
11156 WARN_ON_ONCE(child_ctx->is_active);
11159 perf_group_detach(child_event);
11160 list_del_event(child_event, child_ctx);
11161 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
11162 raw_spin_unlock_irq(&child_ctx->lock);
11165 * Parent events are governed by their filedesc, retain them.
11167 if (!parent_event) {
11168 perf_event_wakeup(child_event);
11172 * Child events can be cleaned up.
11175 sync_child_event(child_event, child);
11178 * Remove this event from the parent's list
11180 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
11181 mutex_lock(&parent_event->child_mutex);
11182 list_del_init(&child_event->child_list);
11183 mutex_unlock(&parent_event->child_mutex);
11186 * Kick perf_poll() for is_event_hup().
11188 perf_event_wakeup(parent_event);
11189 free_event(child_event);
11190 put_event(parent_event);
11193 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
11195 struct perf_event_context *child_ctx, *clone_ctx = NULL;
11196 struct perf_event *child_event, *next;
11198 WARN_ON_ONCE(child != current);
11200 child_ctx = perf_pin_task_context(child, ctxn);
11205 * In order to reduce the amount of tricky in ctx tear-down, we hold
11206 * ctx::mutex over the entire thing. This serializes against almost
11207 * everything that wants to access the ctx.
11209 * The exception is sys_perf_event_open() /
11210 * perf_event_create_kernel_count() which does find_get_context()
11211 * without ctx::mutex (it cannot because of the move_group double mutex
11212 * lock thing). See the comments in perf_install_in_context().
11214 mutex_lock(&child_ctx->mutex);
11217 * In a single ctx::lock section, de-schedule the events and detach the
11218 * context from the task such that we cannot ever get it scheduled back
11221 raw_spin_lock_irq(&child_ctx->lock);
11222 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
11225 * Now that the context is inactive, destroy the task <-> ctx relation
11226 * and mark the context dead.
11228 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
11229 put_ctx(child_ctx); /* cannot be last */
11230 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
11231 put_task_struct(current); /* cannot be last */
11233 clone_ctx = unclone_ctx(child_ctx);
11234 raw_spin_unlock_irq(&child_ctx->lock);
11237 put_ctx(clone_ctx);
11240 * Report the task dead after unscheduling the events so that we
11241 * won't get any samples after PERF_RECORD_EXIT. We can however still
11242 * get a few PERF_RECORD_READ events.
11244 perf_event_task(child, child_ctx, 0);
11246 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
11247 perf_event_exit_event(child_event, child_ctx, child);
11249 mutex_unlock(&child_ctx->mutex);
11251 put_ctx(child_ctx);
11255 * When a child task exits, feed back event values to parent events.
11257 * Can be called with cred_guard_mutex held when called from
11258 * install_exec_creds().
11260 void perf_event_exit_task(struct task_struct *child)
11262 struct perf_event *event, *tmp;
11265 mutex_lock(&child->perf_event_mutex);
11266 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
11268 list_del_init(&event->owner_entry);
11271 * Ensure the list deletion is visible before we clear
11272 * the owner, closes a race against perf_release() where
11273 * we need to serialize on the owner->perf_event_mutex.
11275 smp_store_release(&event->owner, NULL);
11277 mutex_unlock(&child->perf_event_mutex);
11279 for_each_task_context_nr(ctxn)
11280 perf_event_exit_task_context(child, ctxn);
11283 * The perf_event_exit_task_context calls perf_event_task
11284 * with child's task_ctx, which generates EXIT events for
11285 * child contexts and sets child->perf_event_ctxp[] to NULL.
11286 * At this point we need to send EXIT events to cpu contexts.
11288 perf_event_task(child, NULL, 0);
11291 static void perf_free_event(struct perf_event *event,
11292 struct perf_event_context *ctx)
11294 struct perf_event *parent = event->parent;
11296 if (WARN_ON_ONCE(!parent))
11299 mutex_lock(&parent->child_mutex);
11300 list_del_init(&event->child_list);
11301 mutex_unlock(&parent->child_mutex);
11305 raw_spin_lock_irq(&ctx->lock);
11306 perf_group_detach(event);
11307 list_del_event(event, ctx);
11308 raw_spin_unlock_irq(&ctx->lock);
11313 * Free a context as created by inheritance by perf_event_init_task() below,
11314 * used by fork() in case of fail.
11316 * Even though the task has never lived, the context and events have been
11317 * exposed through the child_list, so we must take care tearing it all down.
11319 void perf_event_free_task(struct task_struct *task)
11321 struct perf_event_context *ctx;
11322 struct perf_event *event, *tmp;
11325 for_each_task_context_nr(ctxn) {
11326 ctx = task->perf_event_ctxp[ctxn];
11330 mutex_lock(&ctx->mutex);
11331 raw_spin_lock_irq(&ctx->lock);
11333 * Destroy the task <-> ctx relation and mark the context dead.
11335 * This is important because even though the task hasn't been
11336 * exposed yet the context has been (through child_list).
11338 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
11339 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
11340 put_task_struct(task); /* cannot be last */
11341 raw_spin_unlock_irq(&ctx->lock);
11343 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
11344 perf_free_event(event, ctx);
11346 mutex_unlock(&ctx->mutex);
11349 * perf_event_release_kernel() could've stolen some of our
11350 * child events and still have them on its free_list. In that
11351 * case we must wait for these events to have been freed (in
11352 * particular all their references to this task must've been
11355 * Without this copy_process() will unconditionally free this
11356 * task (irrespective of its reference count) and
11357 * _free_event()'s put_task_struct(event->hw.target) will be a
11360 * Wait for all events to drop their context reference.
11362 wait_var_event(&ctx->refcount, atomic_read(&ctx->refcount) == 1);
11363 put_ctx(ctx); /* must be last */
11367 void perf_event_delayed_put(struct task_struct *task)
11371 for_each_task_context_nr(ctxn)
11372 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
11375 struct file *perf_event_get(unsigned int fd)
11379 file = fget_raw(fd);
11381 return ERR_PTR(-EBADF);
11383 if (file->f_op != &perf_fops) {
11385 return ERR_PTR(-EBADF);
11391 const struct perf_event *perf_get_event(struct file *file)
11393 if (file->f_op != &perf_fops)
11394 return ERR_PTR(-EINVAL);
11396 return file->private_data;
11399 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
11402 return ERR_PTR(-EINVAL);
11404 return &event->attr;
11408 * Inherit an event from parent task to child task.
11411 * - valid pointer on success
11412 * - NULL for orphaned events
11413 * - IS_ERR() on error
11415 static struct perf_event *
11416 inherit_event(struct perf_event *parent_event,
11417 struct task_struct *parent,
11418 struct perf_event_context *parent_ctx,
11419 struct task_struct *child,
11420 struct perf_event *group_leader,
11421 struct perf_event_context *child_ctx)
11423 enum perf_event_state parent_state = parent_event->state;
11424 struct perf_event *child_event;
11425 unsigned long flags;
11428 * Instead of creating recursive hierarchies of events,
11429 * we link inherited events back to the original parent,
11430 * which has a filp for sure, which we use as the reference
11433 if (parent_event->parent)
11434 parent_event = parent_event->parent;
11436 child_event = perf_event_alloc(&parent_event->attr,
11439 group_leader, parent_event,
11441 if (IS_ERR(child_event))
11442 return child_event;
11445 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
11446 !child_ctx->task_ctx_data) {
11447 struct pmu *pmu = child_event->pmu;
11449 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
11451 if (!child_ctx->task_ctx_data) {
11452 free_event(child_event);
11453 return ERR_PTR(-ENOMEM);
11458 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
11459 * must be under the same lock in order to serialize against
11460 * perf_event_release_kernel(), such that either we must observe
11461 * is_orphaned_event() or they will observe us on the child_list.
11463 mutex_lock(&parent_event->child_mutex);
11464 if (is_orphaned_event(parent_event) ||
11465 !atomic_long_inc_not_zero(&parent_event->refcount)) {
11466 mutex_unlock(&parent_event->child_mutex);
11467 /* task_ctx_data is freed with child_ctx */
11468 free_event(child_event);
11472 get_ctx(child_ctx);
11475 * Make the child state follow the state of the parent event,
11476 * not its attr.disabled bit. We hold the parent's mutex,
11477 * so we won't race with perf_event_{en, dis}able_family.
11479 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
11480 child_event->state = PERF_EVENT_STATE_INACTIVE;
11482 child_event->state = PERF_EVENT_STATE_OFF;
11484 if (parent_event->attr.freq) {
11485 u64 sample_period = parent_event->hw.sample_period;
11486 struct hw_perf_event *hwc = &child_event->hw;
11488 hwc->sample_period = sample_period;
11489 hwc->last_period = sample_period;
11491 local64_set(&hwc->period_left, sample_period);
11494 child_event->ctx = child_ctx;
11495 child_event->overflow_handler = parent_event->overflow_handler;
11496 child_event->overflow_handler_context
11497 = parent_event->overflow_handler_context;
11500 * Precalculate sample_data sizes
11502 perf_event__header_size(child_event);
11503 perf_event__id_header_size(child_event);
11506 * Link it up in the child's context:
11508 raw_spin_lock_irqsave(&child_ctx->lock, flags);
11509 add_event_to_ctx(child_event, child_ctx);
11510 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
11513 * Link this into the parent event's child list
11515 list_add_tail(&child_event->child_list, &parent_event->child_list);
11516 mutex_unlock(&parent_event->child_mutex);
11518 return child_event;
11522 * Inherits an event group.
11524 * This will quietly suppress orphaned events; !inherit_event() is not an error.
11525 * This matches with perf_event_release_kernel() removing all child events.
11531 static int inherit_group(struct perf_event *parent_event,
11532 struct task_struct *parent,
11533 struct perf_event_context *parent_ctx,
11534 struct task_struct *child,
11535 struct perf_event_context *child_ctx)
11537 struct perf_event *leader;
11538 struct perf_event *sub;
11539 struct perf_event *child_ctr;
11541 leader = inherit_event(parent_event, parent, parent_ctx,
11542 child, NULL, child_ctx);
11543 if (IS_ERR(leader))
11544 return PTR_ERR(leader);
11546 * @leader can be NULL here because of is_orphaned_event(). In this
11547 * case inherit_event() will create individual events, similar to what
11548 * perf_group_detach() would do anyway.
11550 for_each_sibling_event(sub, parent_event) {
11551 child_ctr = inherit_event(sub, parent, parent_ctx,
11552 child, leader, child_ctx);
11553 if (IS_ERR(child_ctr))
11554 return PTR_ERR(child_ctr);
11560 * Creates the child task context and tries to inherit the event-group.
11562 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
11563 * inherited_all set when we 'fail' to inherit an orphaned event; this is
11564 * consistent with perf_event_release_kernel() removing all child events.
11571 inherit_task_group(struct perf_event *event, struct task_struct *parent,
11572 struct perf_event_context *parent_ctx,
11573 struct task_struct *child, int ctxn,
11574 int *inherited_all)
11577 struct perf_event_context *child_ctx;
11579 if (!event->attr.inherit) {
11580 *inherited_all = 0;
11584 child_ctx = child->perf_event_ctxp[ctxn];
11587 * This is executed from the parent task context, so
11588 * inherit events that have been marked for cloning.
11589 * First allocate and initialize a context for the
11592 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
11596 child->perf_event_ctxp[ctxn] = child_ctx;
11599 ret = inherit_group(event, parent, parent_ctx,
11603 *inherited_all = 0;
11609 * Initialize the perf_event context in task_struct
11611 static int perf_event_init_context(struct task_struct *child, int ctxn)
11613 struct perf_event_context *child_ctx, *parent_ctx;
11614 struct perf_event_context *cloned_ctx;
11615 struct perf_event *event;
11616 struct task_struct *parent = current;
11617 int inherited_all = 1;
11618 unsigned long flags;
11621 if (likely(!parent->perf_event_ctxp[ctxn]))
11625 * If the parent's context is a clone, pin it so it won't get
11626 * swapped under us.
11628 parent_ctx = perf_pin_task_context(parent, ctxn);
11633 * No need to check if parent_ctx != NULL here; since we saw
11634 * it non-NULL earlier, the only reason for it to become NULL
11635 * is if we exit, and since we're currently in the middle of
11636 * a fork we can't be exiting at the same time.
11640 * Lock the parent list. No need to lock the child - not PID
11641 * hashed yet and not running, so nobody can access it.
11643 mutex_lock(&parent_ctx->mutex);
11646 * We dont have to disable NMIs - we are only looking at
11647 * the list, not manipulating it:
11649 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
11650 ret = inherit_task_group(event, parent, parent_ctx,
11651 child, ctxn, &inherited_all);
11657 * We can't hold ctx->lock when iterating the ->flexible_group list due
11658 * to allocations, but we need to prevent rotation because
11659 * rotate_ctx() will change the list from interrupt context.
11661 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11662 parent_ctx->rotate_disable = 1;
11663 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11665 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
11666 ret = inherit_task_group(event, parent, parent_ctx,
11667 child, ctxn, &inherited_all);
11672 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11673 parent_ctx->rotate_disable = 0;
11675 child_ctx = child->perf_event_ctxp[ctxn];
11677 if (child_ctx && inherited_all) {
11679 * Mark the child context as a clone of the parent
11680 * context, or of whatever the parent is a clone of.
11682 * Note that if the parent is a clone, the holding of
11683 * parent_ctx->lock avoids it from being uncloned.
11685 cloned_ctx = parent_ctx->parent_ctx;
11687 child_ctx->parent_ctx = cloned_ctx;
11688 child_ctx->parent_gen = parent_ctx->parent_gen;
11690 child_ctx->parent_ctx = parent_ctx;
11691 child_ctx->parent_gen = parent_ctx->generation;
11693 get_ctx(child_ctx->parent_ctx);
11696 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11698 mutex_unlock(&parent_ctx->mutex);
11700 perf_unpin_context(parent_ctx);
11701 put_ctx(parent_ctx);
11707 * Initialize the perf_event context in task_struct
11709 int perf_event_init_task(struct task_struct *child)
11713 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
11714 mutex_init(&child->perf_event_mutex);
11715 INIT_LIST_HEAD(&child->perf_event_list);
11717 for_each_task_context_nr(ctxn) {
11718 ret = perf_event_init_context(child, ctxn);
11720 perf_event_free_task(child);
11728 static void __init perf_event_init_all_cpus(void)
11730 struct swevent_htable *swhash;
11733 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
11735 for_each_possible_cpu(cpu) {
11736 swhash = &per_cpu(swevent_htable, cpu);
11737 mutex_init(&swhash->hlist_mutex);
11738 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
11740 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
11741 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
11743 #ifdef CONFIG_CGROUP_PERF
11744 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
11746 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
11750 void perf_swevent_init_cpu(unsigned int cpu)
11752 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
11754 mutex_lock(&swhash->hlist_mutex);
11755 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11756 struct swevent_hlist *hlist;
11758 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11760 rcu_assign_pointer(swhash->swevent_hlist, hlist);
11762 mutex_unlock(&swhash->hlist_mutex);
11765 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11766 static void __perf_event_exit_context(void *__info)
11768 struct perf_event_context *ctx = __info;
11769 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11770 struct perf_event *event;
11772 raw_spin_lock(&ctx->lock);
11773 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
11774 list_for_each_entry(event, &ctx->event_list, event_entry)
11775 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11776 raw_spin_unlock(&ctx->lock);
11779 static void perf_event_exit_cpu_context(int cpu)
11781 struct perf_cpu_context *cpuctx;
11782 struct perf_event_context *ctx;
11785 mutex_lock(&pmus_lock);
11786 list_for_each_entry(pmu, &pmus, entry) {
11787 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11788 ctx = &cpuctx->ctx;
11790 mutex_lock(&ctx->mutex);
11791 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11792 cpuctx->online = 0;
11793 mutex_unlock(&ctx->mutex);
11795 cpumask_clear_cpu(cpu, perf_online_mask);
11796 mutex_unlock(&pmus_lock);
11800 static void perf_event_exit_cpu_context(int cpu) { }
11804 int perf_event_init_cpu(unsigned int cpu)
11806 struct perf_cpu_context *cpuctx;
11807 struct perf_event_context *ctx;
11810 perf_swevent_init_cpu(cpu);
11812 mutex_lock(&pmus_lock);
11813 cpumask_set_cpu(cpu, perf_online_mask);
11814 list_for_each_entry(pmu, &pmus, entry) {
11815 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11816 ctx = &cpuctx->ctx;
11818 mutex_lock(&ctx->mutex);
11819 cpuctx->online = 1;
11820 mutex_unlock(&ctx->mutex);
11822 mutex_unlock(&pmus_lock);
11827 int perf_event_exit_cpu(unsigned int cpu)
11829 perf_event_exit_cpu_context(cpu);
11834 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11838 for_each_online_cpu(cpu)
11839 perf_event_exit_cpu(cpu);
11845 * Run the perf reboot notifier at the very last possible moment so that
11846 * the generic watchdog code runs as long as possible.
11848 static struct notifier_block perf_reboot_notifier = {
11849 .notifier_call = perf_reboot,
11850 .priority = INT_MIN,
11853 void __init perf_event_init(void)
11857 idr_init(&pmu_idr);
11859 perf_event_init_all_cpus();
11860 init_srcu_struct(&pmus_srcu);
11861 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11862 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11863 perf_pmu_register(&perf_task_clock, NULL, -1);
11864 perf_tp_register();
11865 perf_event_init_cpu(smp_processor_id());
11866 register_reboot_notifier(&perf_reboot_notifier);
11868 ret = init_hw_breakpoint();
11869 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11872 * Build time assertion that we keep the data_head at the intended
11873 * location. IOW, validation we got the __reserved[] size right.
11875 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11879 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
11882 struct perf_pmu_events_attr *pmu_attr =
11883 container_of(attr, struct perf_pmu_events_attr, attr);
11885 if (pmu_attr->event_str)
11886 return sprintf(page, "%s\n", pmu_attr->event_str);
11890 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
11892 static int __init perf_event_sysfs_init(void)
11897 mutex_lock(&pmus_lock);
11899 ret = bus_register(&pmu_bus);
11903 list_for_each_entry(pmu, &pmus, entry) {
11904 if (!pmu->name || pmu->type < 0)
11907 ret = pmu_dev_alloc(pmu);
11908 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
11910 pmu_bus_running = 1;
11914 mutex_unlock(&pmus_lock);
11918 device_initcall(perf_event_sysfs_init);
11920 #ifdef CONFIG_CGROUP_PERF
11921 static struct cgroup_subsys_state *
11922 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
11924 struct perf_cgroup *jc;
11926 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
11928 return ERR_PTR(-ENOMEM);
11930 jc->info = alloc_percpu(struct perf_cgroup_info);
11933 return ERR_PTR(-ENOMEM);
11939 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
11941 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
11943 free_percpu(jc->info);
11947 static int __perf_cgroup_move(void *info)
11949 struct task_struct *task = info;
11951 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
11956 static void perf_cgroup_attach(struct cgroup_taskset *tset)
11958 struct task_struct *task;
11959 struct cgroup_subsys_state *css;
11961 cgroup_taskset_for_each(task, css, tset)
11962 task_function_call(task, __perf_cgroup_move, task);
11965 struct cgroup_subsys perf_event_cgrp_subsys = {
11966 .css_alloc = perf_cgroup_css_alloc,
11967 .css_free = perf_cgroup_css_free,
11968 .attach = perf_cgroup_attach,
11970 * Implicitly enable on dfl hierarchy so that perf events can
11971 * always be filtered by cgroup2 path as long as perf_event
11972 * controller is not mounted on a legacy hierarchy.
11974 .implicit_on_dfl = true,
11977 #endif /* CONFIG_CGROUP_PERF */