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) {
2089 ctx->rotate_necessary = 0;
2091 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2092 cpuctx->task_ctx = NULL;
2098 * Remove the event from a task's (or a CPU's) list of events.
2100 * If event->ctx is a cloned context, callers must make sure that
2101 * every task struct that event->ctx->task could possibly point to
2102 * remains valid. This is OK when called from perf_release since
2103 * that only calls us on the top-level context, which can't be a clone.
2104 * When called from perf_event_exit_task, it's OK because the
2105 * context has been detached from its task.
2107 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2109 struct perf_event_context *ctx = event->ctx;
2111 lockdep_assert_held(&ctx->mutex);
2113 event_function_call(event, __perf_remove_from_context, (void *)flags);
2116 * The above event_function_call() can NO-OP when it hits
2117 * TASK_TOMBSTONE. In that case we must already have been detached
2118 * from the context (by perf_event_exit_event()) but the grouping
2119 * might still be in-tact.
2121 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
2122 if ((flags & DETACH_GROUP) &&
2123 (event->attach_state & PERF_ATTACH_GROUP)) {
2125 * Since in that case we cannot possibly be scheduled, simply
2128 raw_spin_lock_irq(&ctx->lock);
2129 perf_group_detach(event);
2130 raw_spin_unlock_irq(&ctx->lock);
2135 * Cross CPU call to disable a performance event
2137 static void __perf_event_disable(struct perf_event *event,
2138 struct perf_cpu_context *cpuctx,
2139 struct perf_event_context *ctx,
2142 if (event->state < PERF_EVENT_STATE_INACTIVE)
2145 if (ctx->is_active & EVENT_TIME) {
2146 update_context_time(ctx);
2147 update_cgrp_time_from_event(event);
2150 if (event == event->group_leader)
2151 group_sched_out(event, cpuctx, ctx);
2153 event_sched_out(event, cpuctx, ctx);
2155 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2161 * If event->ctx is a cloned context, callers must make sure that
2162 * every task struct that event->ctx->task could possibly point to
2163 * remains valid. This condition is satisifed when called through
2164 * perf_event_for_each_child or perf_event_for_each because they
2165 * hold the top-level event's child_mutex, so any descendant that
2166 * goes to exit will block in perf_event_exit_event().
2168 * When called from perf_pending_event it's OK because event->ctx
2169 * is the current context on this CPU and preemption is disabled,
2170 * hence we can't get into perf_event_task_sched_out for this context.
2172 static void _perf_event_disable(struct perf_event *event)
2174 struct perf_event_context *ctx = event->ctx;
2176 raw_spin_lock_irq(&ctx->lock);
2177 if (event->state <= PERF_EVENT_STATE_OFF) {
2178 raw_spin_unlock_irq(&ctx->lock);
2181 raw_spin_unlock_irq(&ctx->lock);
2183 event_function_call(event, __perf_event_disable, NULL);
2186 void perf_event_disable_local(struct perf_event *event)
2188 event_function_local(event, __perf_event_disable, NULL);
2192 * Strictly speaking kernel users cannot create groups and therefore this
2193 * interface does not need the perf_event_ctx_lock() magic.
2195 void perf_event_disable(struct perf_event *event)
2197 struct perf_event_context *ctx;
2199 ctx = perf_event_ctx_lock(event);
2200 _perf_event_disable(event);
2201 perf_event_ctx_unlock(event, ctx);
2203 EXPORT_SYMBOL_GPL(perf_event_disable);
2205 void perf_event_disable_inatomic(struct perf_event *event)
2207 WRITE_ONCE(event->pending_disable, smp_processor_id());
2208 /* can fail, see perf_pending_event_disable() */
2209 irq_work_queue(&event->pending);
2212 static void perf_set_shadow_time(struct perf_event *event,
2213 struct perf_event_context *ctx)
2216 * use the correct time source for the time snapshot
2218 * We could get by without this by leveraging the
2219 * fact that to get to this function, the caller
2220 * has most likely already called update_context_time()
2221 * and update_cgrp_time_xx() and thus both timestamp
2222 * are identical (or very close). Given that tstamp is,
2223 * already adjusted for cgroup, we could say that:
2224 * tstamp - ctx->timestamp
2226 * tstamp - cgrp->timestamp.
2228 * Then, in perf_output_read(), the calculation would
2229 * work with no changes because:
2230 * - event is guaranteed scheduled in
2231 * - no scheduled out in between
2232 * - thus the timestamp would be the same
2234 * But this is a bit hairy.
2236 * So instead, we have an explicit cgroup call to remain
2237 * within the time time source all along. We believe it
2238 * is cleaner and simpler to understand.
2240 if (is_cgroup_event(event))
2241 perf_cgroup_set_shadow_time(event, event->tstamp);
2243 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2246 #define MAX_INTERRUPTS (~0ULL)
2248 static void perf_log_throttle(struct perf_event *event, int enable);
2249 static void perf_log_itrace_start(struct perf_event *event);
2252 event_sched_in(struct perf_event *event,
2253 struct perf_cpu_context *cpuctx,
2254 struct perf_event_context *ctx)
2258 lockdep_assert_held(&ctx->lock);
2260 if (event->state <= PERF_EVENT_STATE_OFF)
2263 WRITE_ONCE(event->oncpu, smp_processor_id());
2265 * Order event::oncpu write to happen before the ACTIVE state is
2266 * visible. This allows perf_event_{stop,read}() to observe the correct
2267 * ->oncpu if it sees ACTIVE.
2270 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2273 * Unthrottle events, since we scheduled we might have missed several
2274 * ticks already, also for a heavily scheduling task there is little
2275 * guarantee it'll get a tick in a timely manner.
2277 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2278 perf_log_throttle(event, 1);
2279 event->hw.interrupts = 0;
2282 perf_pmu_disable(event->pmu);
2284 perf_set_shadow_time(event, ctx);
2286 perf_log_itrace_start(event);
2288 if (event->pmu->add(event, PERF_EF_START)) {
2289 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2295 if (!is_software_event(event))
2296 cpuctx->active_oncpu++;
2297 if (!ctx->nr_active++)
2298 perf_event_ctx_activate(ctx);
2299 if (event->attr.freq && event->attr.sample_freq)
2302 if (event->attr.exclusive)
2303 cpuctx->exclusive = 1;
2306 perf_pmu_enable(event->pmu);
2312 group_sched_in(struct perf_event *group_event,
2313 struct perf_cpu_context *cpuctx,
2314 struct perf_event_context *ctx)
2316 struct perf_event *event, *partial_group = NULL;
2317 struct pmu *pmu = ctx->pmu;
2319 if (group_event->state == PERF_EVENT_STATE_OFF)
2322 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2324 if (event_sched_in(group_event, cpuctx, ctx)) {
2325 pmu->cancel_txn(pmu);
2326 perf_mux_hrtimer_restart(cpuctx);
2331 * Schedule in siblings as one group (if any):
2333 for_each_sibling_event(event, group_event) {
2334 if (event_sched_in(event, cpuctx, ctx)) {
2335 partial_group = event;
2340 if (!pmu->commit_txn(pmu))
2345 * Groups can be scheduled in as one unit only, so undo any
2346 * partial group before returning:
2347 * The events up to the failed event are scheduled out normally.
2349 for_each_sibling_event(event, group_event) {
2350 if (event == partial_group)
2353 event_sched_out(event, cpuctx, ctx);
2355 event_sched_out(group_event, cpuctx, ctx);
2357 pmu->cancel_txn(pmu);
2359 perf_mux_hrtimer_restart(cpuctx);
2365 * Work out whether we can put this event group on the CPU now.
2367 static int group_can_go_on(struct perf_event *event,
2368 struct perf_cpu_context *cpuctx,
2372 * Groups consisting entirely of software events can always go on.
2374 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2377 * If an exclusive group is already on, no other hardware
2380 if (cpuctx->exclusive)
2383 * If this group is exclusive and there are already
2384 * events on the CPU, it can't go on.
2386 if (event->attr.exclusive && cpuctx->active_oncpu)
2389 * Otherwise, try to add it if all previous groups were able
2395 static void add_event_to_ctx(struct perf_event *event,
2396 struct perf_event_context *ctx)
2398 list_add_event(event, ctx);
2399 perf_group_attach(event);
2402 static void ctx_sched_out(struct perf_event_context *ctx,
2403 struct perf_cpu_context *cpuctx,
2404 enum event_type_t event_type);
2406 ctx_sched_in(struct perf_event_context *ctx,
2407 struct perf_cpu_context *cpuctx,
2408 enum event_type_t event_type,
2409 struct task_struct *task);
2411 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2412 struct perf_event_context *ctx,
2413 enum event_type_t event_type)
2415 if (!cpuctx->task_ctx)
2418 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2421 ctx_sched_out(ctx, cpuctx, event_type);
2424 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2425 struct perf_event_context *ctx,
2426 struct task_struct *task)
2428 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2430 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2431 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2433 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2437 * We want to maintain the following priority of scheduling:
2438 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2439 * - task pinned (EVENT_PINNED)
2440 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2441 * - task flexible (EVENT_FLEXIBLE).
2443 * In order to avoid unscheduling and scheduling back in everything every
2444 * time an event is added, only do it for the groups of equal priority and
2447 * This can be called after a batch operation on task events, in which case
2448 * event_type is a bit mask of the types of events involved. For CPU events,
2449 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2451 static void ctx_resched(struct perf_cpu_context *cpuctx,
2452 struct perf_event_context *task_ctx,
2453 enum event_type_t event_type)
2455 enum event_type_t ctx_event_type;
2456 bool cpu_event = !!(event_type & EVENT_CPU);
2459 * If pinned groups are involved, flexible groups also need to be
2462 if (event_type & EVENT_PINNED)
2463 event_type |= EVENT_FLEXIBLE;
2465 ctx_event_type = event_type & EVENT_ALL;
2467 perf_pmu_disable(cpuctx->ctx.pmu);
2469 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2472 * Decide which cpu ctx groups to schedule out based on the types
2473 * of events that caused rescheduling:
2474 * - EVENT_CPU: schedule out corresponding groups;
2475 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2476 * - otherwise, do nothing more.
2479 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2480 else if (ctx_event_type & EVENT_PINNED)
2481 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2483 perf_event_sched_in(cpuctx, task_ctx, current);
2484 perf_pmu_enable(cpuctx->ctx.pmu);
2488 * Cross CPU call to install and enable a performance event
2490 * Very similar to remote_function() + event_function() but cannot assume that
2491 * things like ctx->is_active and cpuctx->task_ctx are set.
2493 static int __perf_install_in_context(void *info)
2495 struct perf_event *event = info;
2496 struct perf_event_context *ctx = event->ctx;
2497 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2498 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2499 bool reprogram = true;
2502 raw_spin_lock(&cpuctx->ctx.lock);
2504 raw_spin_lock(&ctx->lock);
2507 reprogram = (ctx->task == current);
2510 * If the task is running, it must be running on this CPU,
2511 * otherwise we cannot reprogram things.
2513 * If its not running, we don't care, ctx->lock will
2514 * serialize against it becoming runnable.
2516 if (task_curr(ctx->task) && !reprogram) {
2521 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2522 } else if (task_ctx) {
2523 raw_spin_lock(&task_ctx->lock);
2526 #ifdef CONFIG_CGROUP_PERF
2527 if (is_cgroup_event(event)) {
2529 * If the current cgroup doesn't match the event's
2530 * cgroup, we should not try to schedule it.
2532 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2533 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2534 event->cgrp->css.cgroup);
2539 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2540 add_event_to_ctx(event, ctx);
2541 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2543 add_event_to_ctx(event, ctx);
2547 perf_ctx_unlock(cpuctx, task_ctx);
2552 static bool exclusive_event_installable(struct perf_event *event,
2553 struct perf_event_context *ctx);
2556 * Attach a performance event to a context.
2558 * Very similar to event_function_call, see comment there.
2561 perf_install_in_context(struct perf_event_context *ctx,
2562 struct perf_event *event,
2565 struct task_struct *task = READ_ONCE(ctx->task);
2567 lockdep_assert_held(&ctx->mutex);
2569 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2571 if (event->cpu != -1)
2575 * Ensures that if we can observe event->ctx, both the event and ctx
2576 * will be 'complete'. See perf_iterate_sb_cpu().
2578 smp_store_release(&event->ctx, ctx);
2581 cpu_function_call(cpu, __perf_install_in_context, event);
2586 * Should not happen, we validate the ctx is still alive before calling.
2588 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2592 * Installing events is tricky because we cannot rely on ctx->is_active
2593 * to be set in case this is the nr_events 0 -> 1 transition.
2595 * Instead we use task_curr(), which tells us if the task is running.
2596 * However, since we use task_curr() outside of rq::lock, we can race
2597 * against the actual state. This means the result can be wrong.
2599 * If we get a false positive, we retry, this is harmless.
2601 * If we get a false negative, things are complicated. If we are after
2602 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2603 * value must be correct. If we're before, it doesn't matter since
2604 * perf_event_context_sched_in() will program the counter.
2606 * However, this hinges on the remote context switch having observed
2607 * our task->perf_event_ctxp[] store, such that it will in fact take
2608 * ctx::lock in perf_event_context_sched_in().
2610 * We do this by task_function_call(), if the IPI fails to hit the task
2611 * we know any future context switch of task must see the
2612 * perf_event_ctpx[] store.
2616 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2617 * task_cpu() load, such that if the IPI then does not find the task
2618 * running, a future context switch of that task must observe the
2623 if (!task_function_call(task, __perf_install_in_context, event))
2626 raw_spin_lock_irq(&ctx->lock);
2628 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2630 * Cannot happen because we already checked above (which also
2631 * cannot happen), and we hold ctx->mutex, which serializes us
2632 * against perf_event_exit_task_context().
2634 raw_spin_unlock_irq(&ctx->lock);
2638 * If the task is not running, ctx->lock will avoid it becoming so,
2639 * thus we can safely install the event.
2641 if (task_curr(task)) {
2642 raw_spin_unlock_irq(&ctx->lock);
2645 add_event_to_ctx(event, ctx);
2646 raw_spin_unlock_irq(&ctx->lock);
2650 * Cross CPU call to enable a performance event
2652 static void __perf_event_enable(struct perf_event *event,
2653 struct perf_cpu_context *cpuctx,
2654 struct perf_event_context *ctx,
2657 struct perf_event *leader = event->group_leader;
2658 struct perf_event_context *task_ctx;
2660 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2661 event->state <= PERF_EVENT_STATE_ERROR)
2665 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2667 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2669 if (!ctx->is_active)
2672 if (!event_filter_match(event)) {
2673 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2678 * If the event is in a group and isn't the group leader,
2679 * then don't put it on unless the group is on.
2681 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2682 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2686 task_ctx = cpuctx->task_ctx;
2688 WARN_ON_ONCE(task_ctx != ctx);
2690 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2696 * If event->ctx is a cloned context, callers must make sure that
2697 * every task struct that event->ctx->task could possibly point to
2698 * remains valid. This condition is satisfied when called through
2699 * perf_event_for_each_child or perf_event_for_each as described
2700 * for perf_event_disable.
2702 static void _perf_event_enable(struct perf_event *event)
2704 struct perf_event_context *ctx = event->ctx;
2706 raw_spin_lock_irq(&ctx->lock);
2707 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2708 event->state < PERF_EVENT_STATE_ERROR) {
2709 raw_spin_unlock_irq(&ctx->lock);
2714 * If the event is in error state, clear that first.
2716 * That way, if we see the event in error state below, we know that it
2717 * has gone back into error state, as distinct from the task having
2718 * been scheduled away before the cross-call arrived.
2720 if (event->state == PERF_EVENT_STATE_ERROR)
2721 event->state = PERF_EVENT_STATE_OFF;
2722 raw_spin_unlock_irq(&ctx->lock);
2724 event_function_call(event, __perf_event_enable, NULL);
2728 * See perf_event_disable();
2730 void perf_event_enable(struct perf_event *event)
2732 struct perf_event_context *ctx;
2734 ctx = perf_event_ctx_lock(event);
2735 _perf_event_enable(event);
2736 perf_event_ctx_unlock(event, ctx);
2738 EXPORT_SYMBOL_GPL(perf_event_enable);
2740 struct stop_event_data {
2741 struct perf_event *event;
2742 unsigned int restart;
2745 static int __perf_event_stop(void *info)
2747 struct stop_event_data *sd = info;
2748 struct perf_event *event = sd->event;
2750 /* if it's already INACTIVE, do nothing */
2751 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2754 /* matches smp_wmb() in event_sched_in() */
2758 * There is a window with interrupts enabled before we get here,
2759 * so we need to check again lest we try to stop another CPU's event.
2761 if (READ_ONCE(event->oncpu) != smp_processor_id())
2764 event->pmu->stop(event, PERF_EF_UPDATE);
2767 * May race with the actual stop (through perf_pmu_output_stop()),
2768 * but it is only used for events with AUX ring buffer, and such
2769 * events will refuse to restart because of rb::aux_mmap_count==0,
2770 * see comments in perf_aux_output_begin().
2772 * Since this is happening on an event-local CPU, no trace is lost
2776 event->pmu->start(event, 0);
2781 static int perf_event_stop(struct perf_event *event, int restart)
2783 struct stop_event_data sd = {
2790 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2793 /* matches smp_wmb() in event_sched_in() */
2797 * We only want to restart ACTIVE events, so if the event goes
2798 * inactive here (event->oncpu==-1), there's nothing more to do;
2799 * fall through with ret==-ENXIO.
2801 ret = cpu_function_call(READ_ONCE(event->oncpu),
2802 __perf_event_stop, &sd);
2803 } while (ret == -EAGAIN);
2809 * In order to contain the amount of racy and tricky in the address filter
2810 * configuration management, it is a two part process:
2812 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2813 * we update the addresses of corresponding vmas in
2814 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
2815 * (p2) when an event is scheduled in (pmu::add), it calls
2816 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2817 * if the generation has changed since the previous call.
2819 * If (p1) happens while the event is active, we restart it to force (p2).
2821 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2822 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2824 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2825 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2827 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2830 void perf_event_addr_filters_sync(struct perf_event *event)
2832 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2834 if (!has_addr_filter(event))
2837 raw_spin_lock(&ifh->lock);
2838 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2839 event->pmu->addr_filters_sync(event);
2840 event->hw.addr_filters_gen = event->addr_filters_gen;
2842 raw_spin_unlock(&ifh->lock);
2844 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2846 static int _perf_event_refresh(struct perf_event *event, int refresh)
2849 * not supported on inherited events
2851 if (event->attr.inherit || !is_sampling_event(event))
2854 atomic_add(refresh, &event->event_limit);
2855 _perf_event_enable(event);
2861 * See perf_event_disable()
2863 int perf_event_refresh(struct perf_event *event, int refresh)
2865 struct perf_event_context *ctx;
2868 ctx = perf_event_ctx_lock(event);
2869 ret = _perf_event_refresh(event, refresh);
2870 perf_event_ctx_unlock(event, ctx);
2874 EXPORT_SYMBOL_GPL(perf_event_refresh);
2876 static int perf_event_modify_breakpoint(struct perf_event *bp,
2877 struct perf_event_attr *attr)
2881 _perf_event_disable(bp);
2883 err = modify_user_hw_breakpoint_check(bp, attr, true);
2885 if (!bp->attr.disabled)
2886 _perf_event_enable(bp);
2891 static int perf_event_modify_attr(struct perf_event *event,
2892 struct perf_event_attr *attr)
2894 if (event->attr.type != attr->type)
2897 switch (event->attr.type) {
2898 case PERF_TYPE_BREAKPOINT:
2899 return perf_event_modify_breakpoint(event, attr);
2901 /* Place holder for future additions. */
2906 static void ctx_sched_out(struct perf_event_context *ctx,
2907 struct perf_cpu_context *cpuctx,
2908 enum event_type_t event_type)
2910 struct perf_event *event, *tmp;
2911 int is_active = ctx->is_active;
2913 lockdep_assert_held(&ctx->lock);
2915 if (likely(!ctx->nr_events)) {
2917 * See __perf_remove_from_context().
2919 WARN_ON_ONCE(ctx->is_active);
2921 WARN_ON_ONCE(cpuctx->task_ctx);
2925 ctx->is_active &= ~event_type;
2926 if (!(ctx->is_active & EVENT_ALL))
2930 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2931 if (!ctx->is_active)
2932 cpuctx->task_ctx = NULL;
2936 * Always update time if it was set; not only when it changes.
2937 * Otherwise we can 'forget' to update time for any but the last
2938 * context we sched out. For example:
2940 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2941 * ctx_sched_out(.event_type = EVENT_PINNED)
2943 * would only update time for the pinned events.
2945 if (is_active & EVENT_TIME) {
2946 /* update (and stop) ctx time */
2947 update_context_time(ctx);
2948 update_cgrp_time_from_cpuctx(cpuctx);
2951 is_active ^= ctx->is_active; /* changed bits */
2953 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2956 perf_pmu_disable(ctx->pmu);
2957 if (is_active & EVENT_PINNED) {
2958 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
2959 group_sched_out(event, cpuctx, ctx);
2962 if (is_active & EVENT_FLEXIBLE) {
2963 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
2964 group_sched_out(event, cpuctx, ctx);
2967 * Since we cleared EVENT_FLEXIBLE, also clear
2968 * rotate_necessary, is will be reset by
2969 * ctx_flexible_sched_in() when needed.
2971 ctx->rotate_necessary = 0;
2973 perf_pmu_enable(ctx->pmu);
2977 * Test whether two contexts are equivalent, i.e. whether they have both been
2978 * cloned from the same version of the same context.
2980 * Equivalence is measured using a generation number in the context that is
2981 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2982 * and list_del_event().
2984 static int context_equiv(struct perf_event_context *ctx1,
2985 struct perf_event_context *ctx2)
2987 lockdep_assert_held(&ctx1->lock);
2988 lockdep_assert_held(&ctx2->lock);
2990 /* Pinning disables the swap optimization */
2991 if (ctx1->pin_count || ctx2->pin_count)
2994 /* If ctx1 is the parent of ctx2 */
2995 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2998 /* If ctx2 is the parent of ctx1 */
2999 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3003 * If ctx1 and ctx2 have the same parent; we flatten the parent
3004 * hierarchy, see perf_event_init_context().
3006 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3007 ctx1->parent_gen == ctx2->parent_gen)
3014 static void __perf_event_sync_stat(struct perf_event *event,
3015 struct perf_event *next_event)
3019 if (!event->attr.inherit_stat)
3023 * Update the event value, we cannot use perf_event_read()
3024 * because we're in the middle of a context switch and have IRQs
3025 * disabled, which upsets smp_call_function_single(), however
3026 * we know the event must be on the current CPU, therefore we
3027 * don't need to use it.
3029 if (event->state == PERF_EVENT_STATE_ACTIVE)
3030 event->pmu->read(event);
3032 perf_event_update_time(event);
3035 * In order to keep per-task stats reliable we need to flip the event
3036 * values when we flip the contexts.
3038 value = local64_read(&next_event->count);
3039 value = local64_xchg(&event->count, value);
3040 local64_set(&next_event->count, value);
3042 swap(event->total_time_enabled, next_event->total_time_enabled);
3043 swap(event->total_time_running, next_event->total_time_running);
3046 * Since we swizzled the values, update the user visible data too.
3048 perf_event_update_userpage(event);
3049 perf_event_update_userpage(next_event);
3052 static void perf_event_sync_stat(struct perf_event_context *ctx,
3053 struct perf_event_context *next_ctx)
3055 struct perf_event *event, *next_event;
3060 update_context_time(ctx);
3062 event = list_first_entry(&ctx->event_list,
3063 struct perf_event, event_entry);
3065 next_event = list_first_entry(&next_ctx->event_list,
3066 struct perf_event, event_entry);
3068 while (&event->event_entry != &ctx->event_list &&
3069 &next_event->event_entry != &next_ctx->event_list) {
3071 __perf_event_sync_stat(event, next_event);
3073 event = list_next_entry(event, event_entry);
3074 next_event = list_next_entry(next_event, event_entry);
3078 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3079 struct task_struct *next)
3081 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3082 struct perf_event_context *next_ctx;
3083 struct perf_event_context *parent, *next_parent;
3084 struct perf_cpu_context *cpuctx;
3090 cpuctx = __get_cpu_context(ctx);
3091 if (!cpuctx->task_ctx)
3095 next_ctx = next->perf_event_ctxp[ctxn];
3099 parent = rcu_dereference(ctx->parent_ctx);
3100 next_parent = rcu_dereference(next_ctx->parent_ctx);
3102 /* If neither context have a parent context; they cannot be clones. */
3103 if (!parent && !next_parent)
3106 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3108 * Looks like the two contexts are clones, so we might be
3109 * able to optimize the context switch. We lock both
3110 * contexts and check that they are clones under the
3111 * lock (including re-checking that neither has been
3112 * uncloned in the meantime). It doesn't matter which
3113 * order we take the locks because no other cpu could
3114 * be trying to lock both of these tasks.
3116 raw_spin_lock(&ctx->lock);
3117 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3118 if (context_equiv(ctx, next_ctx)) {
3119 WRITE_ONCE(ctx->task, next);
3120 WRITE_ONCE(next_ctx->task, task);
3122 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3125 * RCU_INIT_POINTER here is safe because we've not
3126 * modified the ctx and the above modification of
3127 * ctx->task and ctx->task_ctx_data are immaterial
3128 * since those values are always verified under
3129 * ctx->lock which we're now holding.
3131 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3132 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3136 perf_event_sync_stat(ctx, next_ctx);
3138 raw_spin_unlock(&next_ctx->lock);
3139 raw_spin_unlock(&ctx->lock);
3145 raw_spin_lock(&ctx->lock);
3146 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3147 raw_spin_unlock(&ctx->lock);
3151 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3153 void perf_sched_cb_dec(struct pmu *pmu)
3155 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3157 this_cpu_dec(perf_sched_cb_usages);
3159 if (!--cpuctx->sched_cb_usage)
3160 list_del(&cpuctx->sched_cb_entry);
3164 void perf_sched_cb_inc(struct pmu *pmu)
3166 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3168 if (!cpuctx->sched_cb_usage++)
3169 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3171 this_cpu_inc(perf_sched_cb_usages);
3175 * This function provides the context switch callback to the lower code
3176 * layer. It is invoked ONLY when the context switch callback is enabled.
3178 * This callback is relevant even to per-cpu events; for example multi event
3179 * PEBS requires this to provide PID/TID information. This requires we flush
3180 * all queued PEBS records before we context switch to a new task.
3182 static void perf_pmu_sched_task(struct task_struct *prev,
3183 struct task_struct *next,
3186 struct perf_cpu_context *cpuctx;
3192 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3193 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3195 if (WARN_ON_ONCE(!pmu->sched_task))
3198 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3199 perf_pmu_disable(pmu);
3201 pmu->sched_task(cpuctx->task_ctx, sched_in);
3203 perf_pmu_enable(pmu);
3204 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3208 static void perf_event_switch(struct task_struct *task,
3209 struct task_struct *next_prev, bool sched_in);
3211 #define for_each_task_context_nr(ctxn) \
3212 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3215 * Called from scheduler to remove the events of the current task,
3216 * with interrupts disabled.
3218 * We stop each event and update the event value in event->count.
3220 * This does not protect us against NMI, but disable()
3221 * sets the disabled bit in the control field of event _before_
3222 * accessing the event control register. If a NMI hits, then it will
3223 * not restart the event.
3225 void __perf_event_task_sched_out(struct task_struct *task,
3226 struct task_struct *next)
3230 if (__this_cpu_read(perf_sched_cb_usages))
3231 perf_pmu_sched_task(task, next, false);
3233 if (atomic_read(&nr_switch_events))
3234 perf_event_switch(task, next, false);
3236 for_each_task_context_nr(ctxn)
3237 perf_event_context_sched_out(task, ctxn, next);
3240 * if cgroup events exist on this CPU, then we need
3241 * to check if we have to switch out PMU state.
3242 * cgroup event are system-wide mode only
3244 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3245 perf_cgroup_sched_out(task, next);
3249 * Called with IRQs disabled
3251 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3252 enum event_type_t event_type)
3254 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3257 static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
3258 int (*func)(struct perf_event *, void *), void *data)
3260 struct perf_event **evt, *evt1, *evt2;
3263 evt1 = perf_event_groups_first(groups, -1);
3264 evt2 = perf_event_groups_first(groups, cpu);
3266 while (evt1 || evt2) {
3268 if (evt1->group_index < evt2->group_index)
3278 ret = func(*evt, data);
3282 *evt = perf_event_groups_next(*evt);
3288 struct sched_in_data {
3289 struct perf_event_context *ctx;
3290 struct perf_cpu_context *cpuctx;
3294 static int pinned_sched_in(struct perf_event *event, void *data)
3296 struct sched_in_data *sid = data;
3298 if (event->state <= PERF_EVENT_STATE_OFF)
3301 if (!event_filter_match(event))
3304 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3305 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3306 list_add_tail(&event->active_list, &sid->ctx->pinned_active);
3310 * If this pinned group hasn't been scheduled,
3311 * put it in error state.
3313 if (event->state == PERF_EVENT_STATE_INACTIVE)
3314 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3319 static int flexible_sched_in(struct perf_event *event, void *data)
3321 struct sched_in_data *sid = data;
3323 if (event->state <= PERF_EVENT_STATE_OFF)
3326 if (!event_filter_match(event))
3329 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3330 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3331 list_add_tail(&event->active_list, &sid->ctx->flexible_active);
3333 sid->can_add_hw = 0;
3340 ctx_pinned_sched_in(struct perf_event_context *ctx,
3341 struct perf_cpu_context *cpuctx)
3343 struct sched_in_data sid = {
3349 visit_groups_merge(&ctx->pinned_groups,
3351 pinned_sched_in, &sid);
3355 ctx_flexible_sched_in(struct perf_event_context *ctx,
3356 struct perf_cpu_context *cpuctx)
3358 struct sched_in_data sid = {
3364 visit_groups_merge(&ctx->flexible_groups,
3366 flexible_sched_in, &sid);
3370 ctx_sched_in(struct perf_event_context *ctx,
3371 struct perf_cpu_context *cpuctx,
3372 enum event_type_t event_type,
3373 struct task_struct *task)
3375 int is_active = ctx->is_active;
3378 lockdep_assert_held(&ctx->lock);
3380 if (likely(!ctx->nr_events))
3383 ctx->is_active |= (event_type | EVENT_TIME);
3386 cpuctx->task_ctx = ctx;
3388 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3391 is_active ^= ctx->is_active; /* changed bits */
3393 if (is_active & EVENT_TIME) {
3394 /* start ctx time */
3396 ctx->timestamp = now;
3397 perf_cgroup_set_timestamp(task, ctx);
3401 * First go through the list and put on any pinned groups
3402 * in order to give them the best chance of going on.
3404 if (is_active & EVENT_PINNED)
3405 ctx_pinned_sched_in(ctx, cpuctx);
3407 /* Then walk through the lower prio flexible groups */
3408 if (is_active & EVENT_FLEXIBLE)
3409 ctx_flexible_sched_in(ctx, cpuctx);
3412 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3413 enum event_type_t event_type,
3414 struct task_struct *task)
3416 struct perf_event_context *ctx = &cpuctx->ctx;
3418 ctx_sched_in(ctx, cpuctx, event_type, task);
3421 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3422 struct task_struct *task)
3424 struct perf_cpu_context *cpuctx;
3426 cpuctx = __get_cpu_context(ctx);
3427 if (cpuctx->task_ctx == ctx)
3430 perf_ctx_lock(cpuctx, ctx);
3432 * We must check ctx->nr_events while holding ctx->lock, such
3433 * that we serialize against perf_install_in_context().
3435 if (!ctx->nr_events)
3438 perf_pmu_disable(ctx->pmu);
3440 * We want to keep the following priority order:
3441 * cpu pinned (that don't need to move), task pinned,
3442 * cpu flexible, task flexible.
3444 * However, if task's ctx is not carrying any pinned
3445 * events, no need to flip the cpuctx's events around.
3447 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3448 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3449 perf_event_sched_in(cpuctx, ctx, task);
3450 perf_pmu_enable(ctx->pmu);
3453 perf_ctx_unlock(cpuctx, ctx);
3457 * Called from scheduler to add the events of the current task
3458 * with interrupts disabled.
3460 * We restore the event value and then enable it.
3462 * This does not protect us against NMI, but enable()
3463 * sets the enabled bit in the control field of event _before_
3464 * accessing the event control register. If a NMI hits, then it will
3465 * keep the event running.
3467 void __perf_event_task_sched_in(struct task_struct *prev,
3468 struct task_struct *task)
3470 struct perf_event_context *ctx;
3474 * If cgroup events exist on this CPU, then we need to check if we have
3475 * to switch in PMU state; cgroup event are system-wide mode only.
3477 * Since cgroup events are CPU events, we must schedule these in before
3478 * we schedule in the task events.
3480 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3481 perf_cgroup_sched_in(prev, task);
3483 for_each_task_context_nr(ctxn) {
3484 ctx = task->perf_event_ctxp[ctxn];
3488 perf_event_context_sched_in(ctx, task);
3491 if (atomic_read(&nr_switch_events))
3492 perf_event_switch(task, prev, true);
3494 if (__this_cpu_read(perf_sched_cb_usages))
3495 perf_pmu_sched_task(prev, task, true);
3498 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3500 u64 frequency = event->attr.sample_freq;
3501 u64 sec = NSEC_PER_SEC;
3502 u64 divisor, dividend;
3504 int count_fls, nsec_fls, frequency_fls, sec_fls;
3506 count_fls = fls64(count);
3507 nsec_fls = fls64(nsec);
3508 frequency_fls = fls64(frequency);
3512 * We got @count in @nsec, with a target of sample_freq HZ
3513 * the target period becomes:
3516 * period = -------------------
3517 * @nsec * sample_freq
3522 * Reduce accuracy by one bit such that @a and @b converge
3523 * to a similar magnitude.
3525 #define REDUCE_FLS(a, b) \
3527 if (a##_fls > b##_fls) { \
3537 * Reduce accuracy until either term fits in a u64, then proceed with
3538 * the other, so that finally we can do a u64/u64 division.
3540 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3541 REDUCE_FLS(nsec, frequency);
3542 REDUCE_FLS(sec, count);
3545 if (count_fls + sec_fls > 64) {
3546 divisor = nsec * frequency;
3548 while (count_fls + sec_fls > 64) {
3549 REDUCE_FLS(count, sec);
3553 dividend = count * sec;
3555 dividend = count * sec;
3557 while (nsec_fls + frequency_fls > 64) {
3558 REDUCE_FLS(nsec, frequency);
3562 divisor = nsec * frequency;
3568 return div64_u64(dividend, divisor);
3571 static DEFINE_PER_CPU(int, perf_throttled_count);
3572 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3574 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3576 struct hw_perf_event *hwc = &event->hw;
3577 s64 period, sample_period;
3580 period = perf_calculate_period(event, nsec, count);
3582 delta = (s64)(period - hwc->sample_period);
3583 delta = (delta + 7) / 8; /* low pass filter */
3585 sample_period = hwc->sample_period + delta;
3590 hwc->sample_period = sample_period;
3592 if (local64_read(&hwc->period_left) > 8*sample_period) {
3594 event->pmu->stop(event, PERF_EF_UPDATE);
3596 local64_set(&hwc->period_left, 0);
3599 event->pmu->start(event, PERF_EF_RELOAD);
3604 * combine freq adjustment with unthrottling to avoid two passes over the
3605 * events. At the same time, make sure, having freq events does not change
3606 * the rate of unthrottling as that would introduce bias.
3608 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3611 struct perf_event *event;
3612 struct hw_perf_event *hwc;
3613 u64 now, period = TICK_NSEC;
3617 * only need to iterate over all events iff:
3618 * - context have events in frequency mode (needs freq adjust)
3619 * - there are events to unthrottle on this cpu
3621 if (!(ctx->nr_freq || needs_unthr))
3624 raw_spin_lock(&ctx->lock);
3625 perf_pmu_disable(ctx->pmu);
3627 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3628 if (event->state != PERF_EVENT_STATE_ACTIVE)
3631 if (!event_filter_match(event))
3634 perf_pmu_disable(event->pmu);
3638 if (hwc->interrupts == MAX_INTERRUPTS) {
3639 hwc->interrupts = 0;
3640 perf_log_throttle(event, 1);
3641 event->pmu->start(event, 0);
3644 if (!event->attr.freq || !event->attr.sample_freq)
3648 * stop the event and update event->count
3650 event->pmu->stop(event, PERF_EF_UPDATE);
3652 now = local64_read(&event->count);
3653 delta = now - hwc->freq_count_stamp;
3654 hwc->freq_count_stamp = now;
3658 * reload only if value has changed
3659 * we have stopped the event so tell that
3660 * to perf_adjust_period() to avoid stopping it
3664 perf_adjust_period(event, period, delta, false);
3666 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3668 perf_pmu_enable(event->pmu);
3671 perf_pmu_enable(ctx->pmu);
3672 raw_spin_unlock(&ctx->lock);
3676 * Move @event to the tail of the @ctx's elegible events.
3678 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
3681 * Rotate the first entry last of non-pinned groups. Rotation might be
3682 * disabled by the inheritance code.
3684 if (ctx->rotate_disable)
3687 perf_event_groups_delete(&ctx->flexible_groups, event);
3688 perf_event_groups_insert(&ctx->flexible_groups, event);
3691 static inline struct perf_event *
3692 ctx_first_active(struct perf_event_context *ctx)
3694 return list_first_entry_or_null(&ctx->flexible_active,
3695 struct perf_event, active_list);
3698 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
3700 struct perf_event *cpu_event = NULL, *task_event = NULL;
3701 bool cpu_rotate = false, task_rotate = false;
3702 struct perf_event_context *ctx = NULL;
3705 * Since we run this from IRQ context, nobody can install new
3706 * events, thus the event count values are stable.
3709 if (cpuctx->ctx.nr_events) {
3710 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3714 ctx = cpuctx->task_ctx;
3715 if (ctx && ctx->nr_events) {
3716 if (ctx->nr_events != ctx->nr_active)
3720 if (!(cpu_rotate || task_rotate))
3723 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3724 perf_pmu_disable(cpuctx->ctx.pmu);
3727 task_event = ctx_first_active(ctx);
3729 cpu_event = ctx_first_active(&cpuctx->ctx);
3732 * As per the order given at ctx_resched() first 'pop' task flexible
3733 * and then, if needed CPU flexible.
3735 if (task_event || (ctx && cpu_event))
3736 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3738 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3741 rotate_ctx(ctx, task_event);
3743 rotate_ctx(&cpuctx->ctx, cpu_event);
3745 perf_event_sched_in(cpuctx, ctx, current);
3747 perf_pmu_enable(cpuctx->ctx.pmu);
3748 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3753 void perf_event_task_tick(void)
3755 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3756 struct perf_event_context *ctx, *tmp;
3759 lockdep_assert_irqs_disabled();
3761 __this_cpu_inc(perf_throttled_seq);
3762 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3763 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3765 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3766 perf_adjust_freq_unthr_context(ctx, throttled);
3769 static int event_enable_on_exec(struct perf_event *event,
3770 struct perf_event_context *ctx)
3772 if (!event->attr.enable_on_exec)
3775 event->attr.enable_on_exec = 0;
3776 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3779 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3785 * Enable all of a task's events that have been marked enable-on-exec.
3786 * This expects task == current.
3788 static void perf_event_enable_on_exec(int ctxn)
3790 struct perf_event_context *ctx, *clone_ctx = NULL;
3791 enum event_type_t event_type = 0;
3792 struct perf_cpu_context *cpuctx;
3793 struct perf_event *event;
3794 unsigned long flags;
3797 local_irq_save(flags);
3798 ctx = current->perf_event_ctxp[ctxn];
3799 if (!ctx || !ctx->nr_events)
3802 cpuctx = __get_cpu_context(ctx);
3803 perf_ctx_lock(cpuctx, ctx);
3804 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3805 list_for_each_entry(event, &ctx->event_list, event_entry) {
3806 enabled |= event_enable_on_exec(event, ctx);
3807 event_type |= get_event_type(event);
3811 * Unclone and reschedule this context if we enabled any event.
3814 clone_ctx = unclone_ctx(ctx);
3815 ctx_resched(cpuctx, ctx, event_type);
3817 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3819 perf_ctx_unlock(cpuctx, ctx);
3822 local_irq_restore(flags);
3828 struct perf_read_data {
3829 struct perf_event *event;
3834 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3836 u16 local_pkg, event_pkg;
3838 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3839 int local_cpu = smp_processor_id();
3841 event_pkg = topology_physical_package_id(event_cpu);
3842 local_pkg = topology_physical_package_id(local_cpu);
3844 if (event_pkg == local_pkg)
3852 * Cross CPU call to read the hardware event
3854 static void __perf_event_read(void *info)
3856 struct perf_read_data *data = info;
3857 struct perf_event *sub, *event = data->event;
3858 struct perf_event_context *ctx = event->ctx;
3859 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3860 struct pmu *pmu = event->pmu;
3863 * If this is a task context, we need to check whether it is
3864 * the current task context of this cpu. If not it has been
3865 * scheduled out before the smp call arrived. In that case
3866 * event->count would have been updated to a recent sample
3867 * when the event was scheduled out.
3869 if (ctx->task && cpuctx->task_ctx != ctx)
3872 raw_spin_lock(&ctx->lock);
3873 if (ctx->is_active & EVENT_TIME) {
3874 update_context_time(ctx);
3875 update_cgrp_time_from_event(event);
3878 perf_event_update_time(event);
3880 perf_event_update_sibling_time(event);
3882 if (event->state != PERF_EVENT_STATE_ACTIVE)
3891 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3895 for_each_sibling_event(sub, event) {
3896 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3898 * Use sibling's PMU rather than @event's since
3899 * sibling could be on different (eg: software) PMU.
3901 sub->pmu->read(sub);
3905 data->ret = pmu->commit_txn(pmu);
3908 raw_spin_unlock(&ctx->lock);
3911 static inline u64 perf_event_count(struct perf_event *event)
3913 return local64_read(&event->count) + atomic64_read(&event->child_count);
3917 * NMI-safe method to read a local event, that is an event that
3919 * - either for the current task, or for this CPU
3920 * - does not have inherit set, for inherited task events
3921 * will not be local and we cannot read them atomically
3922 * - must not have a pmu::count method
3924 int perf_event_read_local(struct perf_event *event, u64 *value,
3925 u64 *enabled, u64 *running)
3927 unsigned long flags;
3931 * Disabling interrupts avoids all counter scheduling (context
3932 * switches, timer based rotation and IPIs).
3934 local_irq_save(flags);
3937 * It must not be an event with inherit set, we cannot read
3938 * all child counters from atomic context.
3940 if (event->attr.inherit) {
3945 /* If this is a per-task event, it must be for current */
3946 if ((event->attach_state & PERF_ATTACH_TASK) &&
3947 event->hw.target != current) {
3952 /* If this is a per-CPU event, it must be for this CPU */
3953 if (!(event->attach_state & PERF_ATTACH_TASK) &&
3954 event->cpu != smp_processor_id()) {
3959 /* If this is a pinned event it must be running on this CPU */
3960 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
3966 * If the event is currently on this CPU, its either a per-task event,
3967 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3970 if (event->oncpu == smp_processor_id())
3971 event->pmu->read(event);
3973 *value = local64_read(&event->count);
3974 if (enabled || running) {
3975 u64 now = event->shadow_ctx_time + perf_clock();
3976 u64 __enabled, __running;
3978 __perf_update_times(event, now, &__enabled, &__running);
3980 *enabled = __enabled;
3982 *running = __running;
3985 local_irq_restore(flags);
3990 static int perf_event_read(struct perf_event *event, bool group)
3992 enum perf_event_state state = READ_ONCE(event->state);
3993 int event_cpu, ret = 0;
3996 * If event is enabled and currently active on a CPU, update the
3997 * value in the event structure:
4000 if (state == PERF_EVENT_STATE_ACTIVE) {
4001 struct perf_read_data data;
4004 * Orders the ->state and ->oncpu loads such that if we see
4005 * ACTIVE we must also see the right ->oncpu.
4007 * Matches the smp_wmb() from event_sched_in().
4011 event_cpu = READ_ONCE(event->oncpu);
4012 if ((unsigned)event_cpu >= nr_cpu_ids)
4015 data = (struct perf_read_data){
4022 event_cpu = __perf_event_read_cpu(event, event_cpu);
4025 * Purposely ignore the smp_call_function_single() return
4028 * If event_cpu isn't a valid CPU it means the event got
4029 * scheduled out and that will have updated the event count.
4031 * Therefore, either way, we'll have an up-to-date event count
4034 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4038 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4039 struct perf_event_context *ctx = event->ctx;
4040 unsigned long flags;
4042 raw_spin_lock_irqsave(&ctx->lock, flags);
4043 state = event->state;
4044 if (state != PERF_EVENT_STATE_INACTIVE) {
4045 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4050 * May read while context is not active (e.g., thread is
4051 * blocked), in that case we cannot update context time
4053 if (ctx->is_active & EVENT_TIME) {
4054 update_context_time(ctx);
4055 update_cgrp_time_from_event(event);
4058 perf_event_update_time(event);
4060 perf_event_update_sibling_time(event);
4061 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4068 * Initialize the perf_event context in a task_struct:
4070 static void __perf_event_init_context(struct perf_event_context *ctx)
4072 raw_spin_lock_init(&ctx->lock);
4073 mutex_init(&ctx->mutex);
4074 INIT_LIST_HEAD(&ctx->active_ctx_list);
4075 perf_event_groups_init(&ctx->pinned_groups);
4076 perf_event_groups_init(&ctx->flexible_groups);
4077 INIT_LIST_HEAD(&ctx->event_list);
4078 INIT_LIST_HEAD(&ctx->pinned_active);
4079 INIT_LIST_HEAD(&ctx->flexible_active);
4080 atomic_set(&ctx->refcount, 1);
4083 static struct perf_event_context *
4084 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4086 struct perf_event_context *ctx;
4088 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4092 __perf_event_init_context(ctx);
4095 get_task_struct(task);
4102 static struct task_struct *
4103 find_lively_task_by_vpid(pid_t vpid)
4105 struct task_struct *task;
4111 task = find_task_by_vpid(vpid);
4113 get_task_struct(task);
4117 return ERR_PTR(-ESRCH);
4123 * Returns a matching context with refcount and pincount.
4125 static struct perf_event_context *
4126 find_get_context(struct pmu *pmu, struct task_struct *task,
4127 struct perf_event *event)
4129 struct perf_event_context *ctx, *clone_ctx = NULL;
4130 struct perf_cpu_context *cpuctx;
4131 void *task_ctx_data = NULL;
4132 unsigned long flags;
4134 int cpu = event->cpu;
4137 /* Must be root to operate on a CPU event: */
4138 err = perf_allow_cpu(&event->attr);
4140 return ERR_PTR(err);
4142 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4145 raw_spin_lock_irqsave(&ctx->lock, flags);
4147 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4153 ctxn = pmu->task_ctx_nr;
4157 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4158 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4159 if (!task_ctx_data) {
4166 ctx = perf_lock_task_context(task, ctxn, &flags);
4168 clone_ctx = unclone_ctx(ctx);
4171 if (task_ctx_data && !ctx->task_ctx_data) {
4172 ctx->task_ctx_data = task_ctx_data;
4173 task_ctx_data = NULL;
4175 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4180 ctx = alloc_perf_context(pmu, task);
4185 if (task_ctx_data) {
4186 ctx->task_ctx_data = task_ctx_data;
4187 task_ctx_data = NULL;
4191 mutex_lock(&task->perf_event_mutex);
4193 * If it has already passed perf_event_exit_task().
4194 * we must see PF_EXITING, it takes this mutex too.
4196 if (task->flags & PF_EXITING)
4198 else if (task->perf_event_ctxp[ctxn])
4203 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4205 mutex_unlock(&task->perf_event_mutex);
4207 if (unlikely(err)) {
4216 kfree(task_ctx_data);
4220 kfree(task_ctx_data);
4221 return ERR_PTR(err);
4224 static void perf_event_free_filter(struct perf_event *event);
4225 static void perf_event_free_bpf_prog(struct perf_event *event);
4227 static void free_event_rcu(struct rcu_head *head)
4229 struct perf_event *event;
4231 event = container_of(head, struct perf_event, rcu_head);
4233 put_pid_ns(event->ns);
4234 perf_event_free_filter(event);
4238 static void ring_buffer_attach(struct perf_event *event,
4239 struct ring_buffer *rb);
4241 static void detach_sb_event(struct perf_event *event)
4243 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4245 raw_spin_lock(&pel->lock);
4246 list_del_rcu(&event->sb_list);
4247 raw_spin_unlock(&pel->lock);
4250 static bool is_sb_event(struct perf_event *event)
4252 struct perf_event_attr *attr = &event->attr;
4257 if (event->attach_state & PERF_ATTACH_TASK)
4260 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4261 attr->comm || attr->comm_exec ||
4263 attr->context_switch)
4268 static void unaccount_pmu_sb_event(struct perf_event *event)
4270 if (is_sb_event(event))
4271 detach_sb_event(event);
4274 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4279 if (is_cgroup_event(event))
4280 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4283 #ifdef CONFIG_NO_HZ_FULL
4284 static DEFINE_SPINLOCK(nr_freq_lock);
4287 static void unaccount_freq_event_nohz(void)
4289 #ifdef CONFIG_NO_HZ_FULL
4290 spin_lock(&nr_freq_lock);
4291 if (atomic_dec_and_test(&nr_freq_events))
4292 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4293 spin_unlock(&nr_freq_lock);
4297 static void unaccount_freq_event(void)
4299 if (tick_nohz_full_enabled())
4300 unaccount_freq_event_nohz();
4302 atomic_dec(&nr_freq_events);
4305 static void unaccount_event(struct perf_event *event)
4312 if (event->attach_state & PERF_ATTACH_TASK)
4314 if (event->attr.mmap || event->attr.mmap_data)
4315 atomic_dec(&nr_mmap_events);
4316 if (event->attr.comm)
4317 atomic_dec(&nr_comm_events);
4318 if (event->attr.namespaces)
4319 atomic_dec(&nr_namespaces_events);
4320 if (event->attr.task)
4321 atomic_dec(&nr_task_events);
4322 if (event->attr.freq)
4323 unaccount_freq_event();
4324 if (event->attr.context_switch) {
4326 atomic_dec(&nr_switch_events);
4328 if (is_cgroup_event(event))
4330 if (has_branch_stack(event))
4334 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4335 schedule_delayed_work(&perf_sched_work, HZ);
4338 unaccount_event_cpu(event, event->cpu);
4340 unaccount_pmu_sb_event(event);
4343 static void perf_sched_delayed(struct work_struct *work)
4345 mutex_lock(&perf_sched_mutex);
4346 if (atomic_dec_and_test(&perf_sched_count))
4347 static_branch_disable(&perf_sched_events);
4348 mutex_unlock(&perf_sched_mutex);
4352 * The following implement mutual exclusion of events on "exclusive" pmus
4353 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4354 * at a time, so we disallow creating events that might conflict, namely:
4356 * 1) cpu-wide events in the presence of per-task events,
4357 * 2) per-task events in the presence of cpu-wide events,
4358 * 3) two matching events on the same context.
4360 * The former two cases are handled in the allocation path (perf_event_alloc(),
4361 * _free_event()), the latter -- before the first perf_install_in_context().
4363 static int exclusive_event_init(struct perf_event *event)
4365 struct pmu *pmu = event->pmu;
4367 if (!is_exclusive_pmu(pmu))
4371 * Prevent co-existence of per-task and cpu-wide events on the
4372 * same exclusive pmu.
4374 * Negative pmu::exclusive_cnt means there are cpu-wide
4375 * events on this "exclusive" pmu, positive means there are
4378 * Since this is called in perf_event_alloc() path, event::ctx
4379 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4380 * to mean "per-task event", because unlike other attach states it
4381 * never gets cleared.
4383 if (event->attach_state & PERF_ATTACH_TASK) {
4384 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4387 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4394 static void exclusive_event_destroy(struct perf_event *event)
4396 struct pmu *pmu = event->pmu;
4398 if (!is_exclusive_pmu(pmu))
4401 /* see comment in exclusive_event_init() */
4402 if (event->attach_state & PERF_ATTACH_TASK)
4403 atomic_dec(&pmu->exclusive_cnt);
4405 atomic_inc(&pmu->exclusive_cnt);
4408 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4410 if ((e1->pmu == e2->pmu) &&
4411 (e1->cpu == e2->cpu ||
4418 static bool exclusive_event_installable(struct perf_event *event,
4419 struct perf_event_context *ctx)
4421 struct perf_event *iter_event;
4422 struct pmu *pmu = event->pmu;
4424 lockdep_assert_held(&ctx->mutex);
4426 if (!is_exclusive_pmu(pmu))
4429 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4430 if (exclusive_event_match(iter_event, event))
4437 static void perf_addr_filters_splice(struct perf_event *event,
4438 struct list_head *head);
4440 static void _free_event(struct perf_event *event)
4442 irq_work_sync(&event->pending);
4444 unaccount_event(event);
4446 security_perf_event_free(event);
4450 * Can happen when we close an event with re-directed output.
4452 * Since we have a 0 refcount, perf_mmap_close() will skip
4453 * over us; possibly making our ring_buffer_put() the last.
4455 mutex_lock(&event->mmap_mutex);
4456 ring_buffer_attach(event, NULL);
4457 mutex_unlock(&event->mmap_mutex);
4460 if (is_cgroup_event(event))
4461 perf_detach_cgroup(event);
4463 if (!event->parent) {
4464 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4465 put_callchain_buffers();
4468 perf_event_free_bpf_prog(event);
4469 perf_addr_filters_splice(event, NULL);
4470 kfree(event->addr_filter_ranges);
4473 event->destroy(event);
4476 * Must be after ->destroy(), due to uprobe_perf_close() using
4479 if (event->hw.target)
4480 put_task_struct(event->hw.target);
4483 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4484 * all task references must be cleaned up.
4487 put_ctx(event->ctx);
4489 exclusive_event_destroy(event);
4490 module_put(event->pmu->module);
4492 call_rcu(&event->rcu_head, free_event_rcu);
4496 * Used to free events which have a known refcount of 1, such as in error paths
4497 * where the event isn't exposed yet and inherited events.
4499 static void free_event(struct perf_event *event)
4501 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4502 "unexpected event refcount: %ld; ptr=%p\n",
4503 atomic_long_read(&event->refcount), event)) {
4504 /* leak to avoid use-after-free */
4512 * Remove user event from the owner task.
4514 static void perf_remove_from_owner(struct perf_event *event)
4516 struct task_struct *owner;
4520 * Matches the smp_store_release() in perf_event_exit_task(). If we
4521 * observe !owner it means the list deletion is complete and we can
4522 * indeed free this event, otherwise we need to serialize on
4523 * owner->perf_event_mutex.
4525 owner = READ_ONCE(event->owner);
4528 * Since delayed_put_task_struct() also drops the last
4529 * task reference we can safely take a new reference
4530 * while holding the rcu_read_lock().
4532 get_task_struct(owner);
4538 * If we're here through perf_event_exit_task() we're already
4539 * holding ctx->mutex which would be an inversion wrt. the
4540 * normal lock order.
4542 * However we can safely take this lock because its the child
4545 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4548 * We have to re-check the event->owner field, if it is cleared
4549 * we raced with perf_event_exit_task(), acquiring the mutex
4550 * ensured they're done, and we can proceed with freeing the
4554 list_del_init(&event->owner_entry);
4555 smp_store_release(&event->owner, NULL);
4557 mutex_unlock(&owner->perf_event_mutex);
4558 put_task_struct(owner);
4562 static void put_event(struct perf_event *event)
4564 if (!atomic_long_dec_and_test(&event->refcount))
4571 * Kill an event dead; while event:refcount will preserve the event
4572 * object, it will not preserve its functionality. Once the last 'user'
4573 * gives up the object, we'll destroy the thing.
4575 int perf_event_release_kernel(struct perf_event *event)
4577 struct perf_event_context *ctx = event->ctx;
4578 struct perf_event *child, *tmp;
4579 LIST_HEAD(free_list);
4582 * If we got here through err_file: fput(event_file); we will not have
4583 * attached to a context yet.
4586 WARN_ON_ONCE(event->attach_state &
4587 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4591 if (!is_kernel_event(event))
4592 perf_remove_from_owner(event);
4594 ctx = perf_event_ctx_lock(event);
4595 WARN_ON_ONCE(ctx->parent_ctx);
4596 perf_remove_from_context(event, DETACH_GROUP);
4598 raw_spin_lock_irq(&ctx->lock);
4600 * Mark this event as STATE_DEAD, there is no external reference to it
4603 * Anybody acquiring event->child_mutex after the below loop _must_
4604 * also see this, most importantly inherit_event() which will avoid
4605 * placing more children on the list.
4607 * Thus this guarantees that we will in fact observe and kill _ALL_
4610 event->state = PERF_EVENT_STATE_DEAD;
4611 raw_spin_unlock_irq(&ctx->lock);
4613 perf_event_ctx_unlock(event, ctx);
4616 mutex_lock(&event->child_mutex);
4617 list_for_each_entry(child, &event->child_list, child_list) {
4620 * Cannot change, child events are not migrated, see the
4621 * comment with perf_event_ctx_lock_nested().
4623 ctx = READ_ONCE(child->ctx);
4625 * Since child_mutex nests inside ctx::mutex, we must jump
4626 * through hoops. We start by grabbing a reference on the ctx.
4628 * Since the event cannot get freed while we hold the
4629 * child_mutex, the context must also exist and have a !0
4635 * Now that we have a ctx ref, we can drop child_mutex, and
4636 * acquire ctx::mutex without fear of it going away. Then we
4637 * can re-acquire child_mutex.
4639 mutex_unlock(&event->child_mutex);
4640 mutex_lock(&ctx->mutex);
4641 mutex_lock(&event->child_mutex);
4644 * Now that we hold ctx::mutex and child_mutex, revalidate our
4645 * state, if child is still the first entry, it didn't get freed
4646 * and we can continue doing so.
4648 tmp = list_first_entry_or_null(&event->child_list,
4649 struct perf_event, child_list);
4651 perf_remove_from_context(child, DETACH_GROUP);
4652 list_move(&child->child_list, &free_list);
4654 * This matches the refcount bump in inherit_event();
4655 * this can't be the last reference.
4660 mutex_unlock(&event->child_mutex);
4661 mutex_unlock(&ctx->mutex);
4665 mutex_unlock(&event->child_mutex);
4667 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4668 void *var = &child->ctx->refcount;
4670 list_del(&child->child_list);
4674 * Wake any perf_event_free_task() waiting for this event to be
4677 smp_mb(); /* pairs with wait_var_event() */
4682 put_event(event); /* Must be the 'last' reference */
4685 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4688 * Called when the last reference to the file is gone.
4690 static int perf_release(struct inode *inode, struct file *file)
4692 perf_event_release_kernel(file->private_data);
4696 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4698 struct perf_event *child;
4704 mutex_lock(&event->child_mutex);
4706 (void)perf_event_read(event, false);
4707 total += perf_event_count(event);
4709 *enabled += event->total_time_enabled +
4710 atomic64_read(&event->child_total_time_enabled);
4711 *running += event->total_time_running +
4712 atomic64_read(&event->child_total_time_running);
4714 list_for_each_entry(child, &event->child_list, child_list) {
4715 (void)perf_event_read(child, false);
4716 total += perf_event_count(child);
4717 *enabled += child->total_time_enabled;
4718 *running += child->total_time_running;
4720 mutex_unlock(&event->child_mutex);
4725 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4727 struct perf_event_context *ctx;
4730 ctx = perf_event_ctx_lock(event);
4731 count = __perf_event_read_value(event, enabled, running);
4732 perf_event_ctx_unlock(event, ctx);
4736 EXPORT_SYMBOL_GPL(perf_event_read_value);
4738 static int __perf_read_group_add(struct perf_event *leader,
4739 u64 read_format, u64 *values)
4741 struct perf_event_context *ctx = leader->ctx;
4742 struct perf_event *sub;
4743 unsigned long flags;
4744 int n = 1; /* skip @nr */
4747 ret = perf_event_read(leader, true);
4751 raw_spin_lock_irqsave(&ctx->lock, flags);
4754 * Since we co-schedule groups, {enabled,running} times of siblings
4755 * will be identical to those of the leader, so we only publish one
4758 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4759 values[n++] += leader->total_time_enabled +
4760 atomic64_read(&leader->child_total_time_enabled);
4763 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4764 values[n++] += leader->total_time_running +
4765 atomic64_read(&leader->child_total_time_running);
4769 * Write {count,id} tuples for every sibling.
4771 values[n++] += perf_event_count(leader);
4772 if (read_format & PERF_FORMAT_ID)
4773 values[n++] = primary_event_id(leader);
4775 for_each_sibling_event(sub, leader) {
4776 values[n++] += perf_event_count(sub);
4777 if (read_format & PERF_FORMAT_ID)
4778 values[n++] = primary_event_id(sub);
4781 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4785 static int perf_read_group(struct perf_event *event,
4786 u64 read_format, char __user *buf)
4788 struct perf_event *leader = event->group_leader, *child;
4789 struct perf_event_context *ctx = leader->ctx;
4793 lockdep_assert_held(&ctx->mutex);
4795 values = kzalloc(event->read_size, GFP_KERNEL);
4799 values[0] = 1 + leader->nr_siblings;
4802 * By locking the child_mutex of the leader we effectively
4803 * lock the child list of all siblings.. XXX explain how.
4805 mutex_lock(&leader->child_mutex);
4807 ret = __perf_read_group_add(leader, read_format, values);
4811 list_for_each_entry(child, &leader->child_list, child_list) {
4812 ret = __perf_read_group_add(child, read_format, values);
4817 mutex_unlock(&leader->child_mutex);
4819 ret = event->read_size;
4820 if (copy_to_user(buf, values, event->read_size))
4825 mutex_unlock(&leader->child_mutex);
4831 static int perf_read_one(struct perf_event *event,
4832 u64 read_format, char __user *buf)
4834 u64 enabled, running;
4838 values[n++] = __perf_event_read_value(event, &enabled, &running);
4839 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4840 values[n++] = enabled;
4841 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4842 values[n++] = running;
4843 if (read_format & PERF_FORMAT_ID)
4844 values[n++] = primary_event_id(event);
4846 if (copy_to_user(buf, values, n * sizeof(u64)))
4849 return n * sizeof(u64);
4852 static bool is_event_hup(struct perf_event *event)
4856 if (event->state > PERF_EVENT_STATE_EXIT)
4859 mutex_lock(&event->child_mutex);
4860 no_children = list_empty(&event->child_list);
4861 mutex_unlock(&event->child_mutex);
4866 * Read the performance event - simple non blocking version for now
4869 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4871 u64 read_format = event->attr.read_format;
4875 * Return end-of-file for a read on an event that is in
4876 * error state (i.e. because it was pinned but it couldn't be
4877 * scheduled on to the CPU at some point).
4879 if (event->state == PERF_EVENT_STATE_ERROR)
4882 if (count < event->read_size)
4885 WARN_ON_ONCE(event->ctx->parent_ctx);
4886 if (read_format & PERF_FORMAT_GROUP)
4887 ret = perf_read_group(event, read_format, buf);
4889 ret = perf_read_one(event, read_format, buf);
4895 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4897 struct perf_event *event = file->private_data;
4898 struct perf_event_context *ctx;
4901 ret = security_perf_event_read(event);
4905 ctx = perf_event_ctx_lock(event);
4906 ret = __perf_read(event, buf, count);
4907 perf_event_ctx_unlock(event, ctx);
4912 static __poll_t perf_poll(struct file *file, poll_table *wait)
4914 struct perf_event *event = file->private_data;
4915 struct ring_buffer *rb;
4916 __poll_t events = EPOLLHUP;
4918 poll_wait(file, &event->waitq, wait);
4920 if (is_event_hup(event))
4924 * Pin the event->rb by taking event->mmap_mutex; otherwise
4925 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4927 mutex_lock(&event->mmap_mutex);
4930 events = atomic_xchg(&rb->poll, 0);
4931 mutex_unlock(&event->mmap_mutex);
4935 static void _perf_event_reset(struct perf_event *event)
4937 (void)perf_event_read(event, false);
4938 local64_set(&event->count, 0);
4939 perf_event_update_userpage(event);
4943 * Holding the top-level event's child_mutex means that any
4944 * descendant process that has inherited this event will block
4945 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4946 * task existence requirements of perf_event_enable/disable.
4948 static void perf_event_for_each_child(struct perf_event *event,
4949 void (*func)(struct perf_event *))
4951 struct perf_event *child;
4953 WARN_ON_ONCE(event->ctx->parent_ctx);
4955 mutex_lock(&event->child_mutex);
4957 list_for_each_entry(child, &event->child_list, child_list)
4959 mutex_unlock(&event->child_mutex);
4962 static void perf_event_for_each(struct perf_event *event,
4963 void (*func)(struct perf_event *))
4965 struct perf_event_context *ctx = event->ctx;
4966 struct perf_event *sibling;
4968 lockdep_assert_held(&ctx->mutex);
4970 event = event->group_leader;
4972 perf_event_for_each_child(event, func);
4973 for_each_sibling_event(sibling, event)
4974 perf_event_for_each_child(sibling, func);
4977 static void __perf_event_period(struct perf_event *event,
4978 struct perf_cpu_context *cpuctx,
4979 struct perf_event_context *ctx,
4982 u64 value = *((u64 *)info);
4985 if (event->attr.freq) {
4986 event->attr.sample_freq = value;
4988 event->attr.sample_period = value;
4989 event->hw.sample_period = value;
4992 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4994 perf_pmu_disable(ctx->pmu);
4996 * We could be throttled; unthrottle now to avoid the tick
4997 * trying to unthrottle while we already re-started the event.
4999 if (event->hw.interrupts == MAX_INTERRUPTS) {
5000 event->hw.interrupts = 0;
5001 perf_log_throttle(event, 1);
5003 event->pmu->stop(event, PERF_EF_UPDATE);
5006 local64_set(&event->hw.period_left, 0);
5009 event->pmu->start(event, PERF_EF_RELOAD);
5010 perf_pmu_enable(ctx->pmu);
5014 static int perf_event_check_period(struct perf_event *event, u64 value)
5016 return event->pmu->check_period(event, value);
5019 static int perf_event_period(struct perf_event *event, u64 __user *arg)
5023 if (!is_sampling_event(event))
5026 if (copy_from_user(&value, arg, sizeof(value)))
5032 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5035 if (perf_event_check_period(event, value))
5038 if (!event->attr.freq && (value & (1ULL << 63)))
5041 event_function_call(event, __perf_event_period, &value);
5046 static const struct file_operations perf_fops;
5048 static inline int perf_fget_light(int fd, struct fd *p)
5050 struct fd f = fdget(fd);
5054 if (f.file->f_op != &perf_fops) {
5062 static int perf_event_set_output(struct perf_event *event,
5063 struct perf_event *output_event);
5064 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5065 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5066 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5067 struct perf_event_attr *attr);
5069 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5071 void (*func)(struct perf_event *);
5075 case PERF_EVENT_IOC_ENABLE:
5076 func = _perf_event_enable;
5078 case PERF_EVENT_IOC_DISABLE:
5079 func = _perf_event_disable;
5081 case PERF_EVENT_IOC_RESET:
5082 func = _perf_event_reset;
5085 case PERF_EVENT_IOC_REFRESH:
5086 return _perf_event_refresh(event, arg);
5088 case PERF_EVENT_IOC_PERIOD:
5089 return perf_event_period(event, (u64 __user *)arg);
5091 case PERF_EVENT_IOC_ID:
5093 u64 id = primary_event_id(event);
5095 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5100 case PERF_EVENT_IOC_SET_OUTPUT:
5104 struct perf_event *output_event;
5106 ret = perf_fget_light(arg, &output);
5109 output_event = output.file->private_data;
5110 ret = perf_event_set_output(event, output_event);
5113 ret = perf_event_set_output(event, NULL);
5118 case PERF_EVENT_IOC_SET_FILTER:
5119 return perf_event_set_filter(event, (void __user *)arg);
5121 case PERF_EVENT_IOC_SET_BPF:
5122 return perf_event_set_bpf_prog(event, arg);
5124 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5125 struct ring_buffer *rb;
5128 rb = rcu_dereference(event->rb);
5129 if (!rb || !rb->nr_pages) {
5133 rb_toggle_paused(rb, !!arg);
5138 case PERF_EVENT_IOC_QUERY_BPF:
5139 return perf_event_query_prog_array(event, (void __user *)arg);
5141 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5142 struct perf_event_attr new_attr;
5143 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5149 return perf_event_modify_attr(event, &new_attr);
5155 if (flags & PERF_IOC_FLAG_GROUP)
5156 perf_event_for_each(event, func);
5158 perf_event_for_each_child(event, func);
5163 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5165 struct perf_event *event = file->private_data;
5166 struct perf_event_context *ctx;
5169 /* Treat ioctl like writes as it is likely a mutating operation. */
5170 ret = security_perf_event_write(event);
5174 ctx = perf_event_ctx_lock(event);
5175 ret = _perf_ioctl(event, cmd, arg);
5176 perf_event_ctx_unlock(event, ctx);
5181 #ifdef CONFIG_COMPAT
5182 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5185 switch (_IOC_NR(cmd)) {
5186 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5187 case _IOC_NR(PERF_EVENT_IOC_ID):
5188 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5189 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5190 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5191 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5192 cmd &= ~IOCSIZE_MASK;
5193 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5197 return perf_ioctl(file, cmd, arg);
5200 # define perf_compat_ioctl NULL
5203 int perf_event_task_enable(void)
5205 struct perf_event_context *ctx;
5206 struct perf_event *event;
5208 mutex_lock(¤t->perf_event_mutex);
5209 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5210 ctx = perf_event_ctx_lock(event);
5211 perf_event_for_each_child(event, _perf_event_enable);
5212 perf_event_ctx_unlock(event, ctx);
5214 mutex_unlock(¤t->perf_event_mutex);
5219 int perf_event_task_disable(void)
5221 struct perf_event_context *ctx;
5222 struct perf_event *event;
5224 mutex_lock(¤t->perf_event_mutex);
5225 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5226 ctx = perf_event_ctx_lock(event);
5227 perf_event_for_each_child(event, _perf_event_disable);
5228 perf_event_ctx_unlock(event, ctx);
5230 mutex_unlock(¤t->perf_event_mutex);
5235 static int perf_event_index(struct perf_event *event)
5237 if (event->hw.state & PERF_HES_STOPPED)
5240 if (event->state != PERF_EVENT_STATE_ACTIVE)
5243 return event->pmu->event_idx(event);
5246 static void calc_timer_values(struct perf_event *event,
5253 *now = perf_clock();
5254 ctx_time = event->shadow_ctx_time + *now;
5255 __perf_update_times(event, ctx_time, enabled, running);
5258 static void perf_event_init_userpage(struct perf_event *event)
5260 struct perf_event_mmap_page *userpg;
5261 struct ring_buffer *rb;
5264 rb = rcu_dereference(event->rb);
5268 userpg = rb->user_page;
5270 /* Allow new userspace to detect that bit 0 is deprecated */
5271 userpg->cap_bit0_is_deprecated = 1;
5272 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5273 userpg->data_offset = PAGE_SIZE;
5274 userpg->data_size = perf_data_size(rb);
5280 void __weak arch_perf_update_userpage(
5281 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5286 * Callers need to ensure there can be no nesting of this function, otherwise
5287 * the seqlock logic goes bad. We can not serialize this because the arch
5288 * code calls this from NMI context.
5290 void perf_event_update_userpage(struct perf_event *event)
5292 struct perf_event_mmap_page *userpg;
5293 struct ring_buffer *rb;
5294 u64 enabled, running, now;
5297 rb = rcu_dereference(event->rb);
5302 * compute total_time_enabled, total_time_running
5303 * based on snapshot values taken when the event
5304 * was last scheduled in.
5306 * we cannot simply called update_context_time()
5307 * because of locking issue as we can be called in
5310 calc_timer_values(event, &now, &enabled, &running);
5312 userpg = rb->user_page;
5314 * Disable preemption to guarantee consistent time stamps are stored to
5320 userpg->index = perf_event_index(event);
5321 userpg->offset = perf_event_count(event);
5323 userpg->offset -= local64_read(&event->hw.prev_count);
5325 userpg->time_enabled = enabled +
5326 atomic64_read(&event->child_total_time_enabled);
5328 userpg->time_running = running +
5329 atomic64_read(&event->child_total_time_running);
5331 arch_perf_update_userpage(event, userpg, now);
5339 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5341 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5343 struct perf_event *event = vmf->vma->vm_file->private_data;
5344 struct ring_buffer *rb;
5345 vm_fault_t ret = VM_FAULT_SIGBUS;
5347 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5348 if (vmf->pgoff == 0)
5354 rb = rcu_dereference(event->rb);
5358 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5361 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5365 get_page(vmf->page);
5366 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5367 vmf->page->index = vmf->pgoff;
5376 static void ring_buffer_attach(struct perf_event *event,
5377 struct ring_buffer *rb)
5379 struct ring_buffer *old_rb = NULL;
5380 unsigned long flags;
5384 * Should be impossible, we set this when removing
5385 * event->rb_entry and wait/clear when adding event->rb_entry.
5387 WARN_ON_ONCE(event->rcu_pending);
5390 spin_lock_irqsave(&old_rb->event_lock, flags);
5391 list_del_rcu(&event->rb_entry);
5392 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5394 event->rcu_batches = get_state_synchronize_rcu();
5395 event->rcu_pending = 1;
5399 if (event->rcu_pending) {
5400 cond_synchronize_rcu(event->rcu_batches);
5401 event->rcu_pending = 0;
5404 spin_lock_irqsave(&rb->event_lock, flags);
5405 list_add_rcu(&event->rb_entry, &rb->event_list);
5406 spin_unlock_irqrestore(&rb->event_lock, flags);
5410 * Avoid racing with perf_mmap_close(AUX): stop the event
5411 * before swizzling the event::rb pointer; if it's getting
5412 * unmapped, its aux_mmap_count will be 0 and it won't
5413 * restart. See the comment in __perf_pmu_output_stop().
5415 * Data will inevitably be lost when set_output is done in
5416 * mid-air, but then again, whoever does it like this is
5417 * not in for the data anyway.
5420 perf_event_stop(event, 0);
5422 rcu_assign_pointer(event->rb, rb);
5425 ring_buffer_put(old_rb);
5427 * Since we detached before setting the new rb, so that we
5428 * could attach the new rb, we could have missed a wakeup.
5431 wake_up_all(&event->waitq);
5435 static void ring_buffer_wakeup(struct perf_event *event)
5437 struct ring_buffer *rb;
5440 rb = rcu_dereference(event->rb);
5442 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5443 wake_up_all(&event->waitq);
5448 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5450 struct ring_buffer *rb;
5453 rb = rcu_dereference(event->rb);
5455 if (!atomic_inc_not_zero(&rb->refcount))
5463 void ring_buffer_put(struct ring_buffer *rb)
5465 if (!atomic_dec_and_test(&rb->refcount))
5468 WARN_ON_ONCE(!list_empty(&rb->event_list));
5470 call_rcu(&rb->rcu_head, rb_free_rcu);
5473 static void perf_mmap_open(struct vm_area_struct *vma)
5475 struct perf_event *event = vma->vm_file->private_data;
5477 atomic_inc(&event->mmap_count);
5478 atomic_inc(&event->rb->mmap_count);
5481 atomic_inc(&event->rb->aux_mmap_count);
5483 if (event->pmu->event_mapped)
5484 event->pmu->event_mapped(event, vma->vm_mm);
5487 static void perf_pmu_output_stop(struct perf_event *event);
5490 * A buffer can be mmap()ed multiple times; either directly through the same
5491 * event, or through other events by use of perf_event_set_output().
5493 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5494 * the buffer here, where we still have a VM context. This means we need
5495 * to detach all events redirecting to us.
5497 static void perf_mmap_close(struct vm_area_struct *vma)
5499 struct perf_event *event = vma->vm_file->private_data;
5500 struct ring_buffer *rb = ring_buffer_get(event);
5501 struct user_struct *mmap_user = rb->mmap_user;
5502 int mmap_locked = rb->mmap_locked;
5503 unsigned long size = perf_data_size(rb);
5504 bool detach_rest = false;
5506 if (event->pmu->event_unmapped)
5507 event->pmu->event_unmapped(event, vma->vm_mm);
5510 * rb->aux_mmap_count will always drop before rb->mmap_count and
5511 * event->mmap_count, so it is ok to use event->mmap_mutex to
5512 * serialize with perf_mmap here.
5514 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5515 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5517 * Stop all AUX events that are writing to this buffer,
5518 * so that we can free its AUX pages and corresponding PMU
5519 * data. Note that after rb::aux_mmap_count dropped to zero,
5520 * they won't start any more (see perf_aux_output_begin()).
5522 perf_pmu_output_stop(event);
5524 /* now it's safe to free the pages */
5525 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5526 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5528 /* this has to be the last one */
5530 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5532 mutex_unlock(&event->mmap_mutex);
5535 if (atomic_dec_and_test(&rb->mmap_count))
5538 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5541 ring_buffer_attach(event, NULL);
5542 mutex_unlock(&event->mmap_mutex);
5544 /* If there's still other mmap()s of this buffer, we're done. */
5549 * No other mmap()s, detach from all other events that might redirect
5550 * into the now unreachable buffer. Somewhat complicated by the
5551 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5555 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5556 if (!atomic_long_inc_not_zero(&event->refcount)) {
5558 * This event is en-route to free_event() which will
5559 * detach it and remove it from the list.
5565 mutex_lock(&event->mmap_mutex);
5567 * Check we didn't race with perf_event_set_output() which can
5568 * swizzle the rb from under us while we were waiting to
5569 * acquire mmap_mutex.
5571 * If we find a different rb; ignore this event, a next
5572 * iteration will no longer find it on the list. We have to
5573 * still restart the iteration to make sure we're not now
5574 * iterating the wrong list.
5576 if (event->rb == rb)
5577 ring_buffer_attach(event, NULL);
5579 mutex_unlock(&event->mmap_mutex);
5583 * Restart the iteration; either we're on the wrong list or
5584 * destroyed its integrity by doing a deletion.
5591 * It could be there's still a few 0-ref events on the list; they'll
5592 * get cleaned up by free_event() -- they'll also still have their
5593 * ref on the rb and will free it whenever they are done with it.
5595 * Aside from that, this buffer is 'fully' detached and unmapped,
5596 * undo the VM accounting.
5599 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5600 vma->vm_mm->pinned_vm -= mmap_locked;
5601 free_uid(mmap_user);
5604 ring_buffer_put(rb); /* could be last */
5607 static const struct vm_operations_struct perf_mmap_vmops = {
5608 .open = perf_mmap_open,
5609 .close = perf_mmap_close, /* non mergable */
5610 .fault = perf_mmap_fault,
5611 .page_mkwrite = perf_mmap_fault,
5614 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5616 struct perf_event *event = file->private_data;
5617 unsigned long user_locked, user_lock_limit;
5618 struct user_struct *user = current_user();
5619 unsigned long locked, lock_limit;
5620 struct ring_buffer *rb = NULL;
5621 unsigned long vma_size;
5622 unsigned long nr_pages;
5623 long user_extra = 0, extra = 0;
5624 int ret = 0, flags = 0;
5627 * Don't allow mmap() of inherited per-task counters. This would
5628 * create a performance issue due to all children writing to the
5631 if (event->cpu == -1 && event->attr.inherit)
5634 if (!(vma->vm_flags & VM_SHARED))
5637 ret = security_perf_event_read(event);
5641 vma_size = vma->vm_end - vma->vm_start;
5643 if (vma->vm_pgoff == 0) {
5644 nr_pages = (vma_size / PAGE_SIZE) - 1;
5647 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5648 * mapped, all subsequent mappings should have the same size
5649 * and offset. Must be above the normal perf buffer.
5651 u64 aux_offset, aux_size;
5656 nr_pages = vma_size / PAGE_SIZE;
5658 mutex_lock(&event->mmap_mutex);
5665 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5666 aux_size = READ_ONCE(rb->user_page->aux_size);
5668 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5671 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5674 /* already mapped with a different offset */
5675 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5678 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5681 /* already mapped with a different size */
5682 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5685 if (!is_power_of_2(nr_pages))
5688 if (!atomic_inc_not_zero(&rb->mmap_count))
5691 if (rb_has_aux(rb)) {
5692 atomic_inc(&rb->aux_mmap_count);
5697 atomic_set(&rb->aux_mmap_count, 1);
5698 user_extra = nr_pages;
5704 * If we have rb pages ensure they're a power-of-two number, so we
5705 * can do bitmasks instead of modulo.
5707 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5710 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5713 WARN_ON_ONCE(event->ctx->parent_ctx);
5715 mutex_lock(&event->mmap_mutex);
5717 if (event->rb->nr_pages != nr_pages) {
5722 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5724 * Raced against perf_mmap_close() through
5725 * perf_event_set_output(). Try again, hope for better
5728 mutex_unlock(&event->mmap_mutex);
5735 user_extra = nr_pages + 1;
5738 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5741 * Increase the limit linearly with more CPUs:
5743 user_lock_limit *= num_online_cpus();
5745 user_locked = atomic_long_read(&user->locked_vm);
5748 * sysctl_perf_event_mlock may have changed, so that
5749 * user->locked_vm > user_lock_limit
5751 if (user_locked > user_lock_limit)
5752 user_locked = user_lock_limit;
5753 user_locked += user_extra;
5755 if (user_locked > user_lock_limit)
5756 extra = user_locked - user_lock_limit;
5758 lock_limit = rlimit(RLIMIT_MEMLOCK);
5759 lock_limit >>= PAGE_SHIFT;
5760 locked = vma->vm_mm->pinned_vm + extra;
5762 if ((locked > lock_limit) && perf_is_paranoid() &&
5763 !capable(CAP_IPC_LOCK)) {
5768 WARN_ON(!rb && event->rb);
5770 if (vma->vm_flags & VM_WRITE)
5771 flags |= RING_BUFFER_WRITABLE;
5774 rb = rb_alloc(nr_pages,
5775 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5783 atomic_set(&rb->mmap_count, 1);
5784 rb->mmap_user = get_current_user();
5785 rb->mmap_locked = extra;
5787 ring_buffer_attach(event, rb);
5789 perf_event_init_userpage(event);
5790 perf_event_update_userpage(event);
5792 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5793 event->attr.aux_watermark, flags);
5795 rb->aux_mmap_locked = extra;
5800 atomic_long_add(user_extra, &user->locked_vm);
5801 vma->vm_mm->pinned_vm += extra;
5803 atomic_inc(&event->mmap_count);
5805 atomic_dec(&rb->mmap_count);
5808 mutex_unlock(&event->mmap_mutex);
5811 * Since pinned accounting is per vm we cannot allow fork() to copy our
5814 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5815 vma->vm_ops = &perf_mmap_vmops;
5817 if (event->pmu->event_mapped)
5818 event->pmu->event_mapped(event, vma->vm_mm);
5823 static int perf_fasync(int fd, struct file *filp, int on)
5825 struct inode *inode = file_inode(filp);
5826 struct perf_event *event = filp->private_data;
5830 retval = fasync_helper(fd, filp, on, &event->fasync);
5831 inode_unlock(inode);
5839 static const struct file_operations perf_fops = {
5840 .llseek = no_llseek,
5841 .release = perf_release,
5844 .unlocked_ioctl = perf_ioctl,
5845 .compat_ioctl = perf_compat_ioctl,
5847 .fasync = perf_fasync,
5853 * If there's data, ensure we set the poll() state and publish everything
5854 * to user-space before waking everybody up.
5857 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5859 /* only the parent has fasync state */
5861 event = event->parent;
5862 return &event->fasync;
5865 void perf_event_wakeup(struct perf_event *event)
5867 ring_buffer_wakeup(event);
5869 if (event->pending_kill) {
5870 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5871 event->pending_kill = 0;
5875 static void perf_pending_event_disable(struct perf_event *event)
5877 int cpu = READ_ONCE(event->pending_disable);
5882 if (cpu == smp_processor_id()) {
5883 WRITE_ONCE(event->pending_disable, -1);
5884 perf_event_disable_local(event);
5891 * perf_event_disable_inatomic()
5892 * @pending_disable = CPU-A;
5896 * @pending_disable = -1;
5899 * perf_event_disable_inatomic()
5900 * @pending_disable = CPU-B;
5901 * irq_work_queue(); // FAILS
5904 * perf_pending_event()
5906 * But the event runs on CPU-B and wants disabling there.
5908 irq_work_queue_on(&event->pending, cpu);
5911 static void perf_pending_event(struct irq_work *entry)
5913 struct perf_event *event = container_of(entry, struct perf_event, pending);
5916 rctx = perf_swevent_get_recursion_context();
5918 * If we 'fail' here, that's OK, it means recursion is already disabled
5919 * and we won't recurse 'further'.
5922 perf_pending_event_disable(event);
5924 if (event->pending_wakeup) {
5925 event->pending_wakeup = 0;
5926 perf_event_wakeup(event);
5930 perf_swevent_put_recursion_context(rctx);
5934 * We assume there is only KVM supporting the callbacks.
5935 * Later on, we might change it to a list if there is
5936 * another virtualization implementation supporting the callbacks.
5938 struct perf_guest_info_callbacks *perf_guest_cbs;
5940 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5942 perf_guest_cbs = cbs;
5945 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5947 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5949 perf_guest_cbs = NULL;
5952 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5955 perf_output_sample_regs(struct perf_output_handle *handle,
5956 struct pt_regs *regs, u64 mask)
5959 DECLARE_BITMAP(_mask, 64);
5961 bitmap_from_u64(_mask, mask);
5962 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5965 val = perf_reg_value(regs, bit);
5966 perf_output_put(handle, val);
5970 static void perf_sample_regs_user(struct perf_regs *regs_user,
5971 struct pt_regs *regs,
5972 struct pt_regs *regs_user_copy)
5974 if (user_mode(regs)) {
5975 regs_user->abi = perf_reg_abi(current);
5976 regs_user->regs = regs;
5977 } else if (!(current->flags & PF_KTHREAD)) {
5978 perf_get_regs_user(regs_user, regs, regs_user_copy);
5980 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5981 regs_user->regs = NULL;
5985 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5986 struct pt_regs *regs)
5988 regs_intr->regs = regs;
5989 regs_intr->abi = perf_reg_abi(current);
5994 * Get remaining task size from user stack pointer.
5996 * It'd be better to take stack vma map and limit this more
5997 * precisly, but there's no way to get it safely under interrupt,
5998 * so using TASK_SIZE as limit.
6000 static u64 perf_ustack_task_size(struct pt_regs *regs)
6002 unsigned long addr = perf_user_stack_pointer(regs);
6004 if (!addr || addr >= TASK_SIZE)
6007 return TASK_SIZE - addr;
6011 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6012 struct pt_regs *regs)
6016 /* No regs, no stack pointer, no dump. */
6021 * Check if we fit in with the requested stack size into the:
6023 * If we don't, we limit the size to the TASK_SIZE.
6025 * - remaining sample size
6026 * If we don't, we customize the stack size to
6027 * fit in to the remaining sample size.
6030 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6031 stack_size = min(stack_size, (u16) task_size);
6033 /* Current header size plus static size and dynamic size. */
6034 header_size += 2 * sizeof(u64);
6036 /* Do we fit in with the current stack dump size? */
6037 if ((u16) (header_size + stack_size) < header_size) {
6039 * If we overflow the maximum size for the sample,
6040 * we customize the stack dump size to fit in.
6042 stack_size = USHRT_MAX - header_size - sizeof(u64);
6043 stack_size = round_up(stack_size, sizeof(u64));
6050 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6051 struct pt_regs *regs)
6053 /* Case of a kernel thread, nothing to dump */
6056 perf_output_put(handle, size);
6066 * - the size requested by user or the best one we can fit
6067 * in to the sample max size
6069 * - user stack dump data
6071 * - the actual dumped size
6075 perf_output_put(handle, dump_size);
6078 sp = perf_user_stack_pointer(regs);
6081 rem = __output_copy_user(handle, (void *) sp, dump_size);
6083 dyn_size = dump_size - rem;
6085 perf_output_skip(handle, rem);
6088 perf_output_put(handle, dyn_size);
6092 static void __perf_event_header__init_id(struct perf_event_header *header,
6093 struct perf_sample_data *data,
6094 struct perf_event *event)
6096 u64 sample_type = event->attr.sample_type;
6098 data->type = sample_type;
6099 header->size += event->id_header_size;
6101 if (sample_type & PERF_SAMPLE_TID) {
6102 /* namespace issues */
6103 data->tid_entry.pid = perf_event_pid(event, current);
6104 data->tid_entry.tid = perf_event_tid(event, current);
6107 if (sample_type & PERF_SAMPLE_TIME)
6108 data->time = perf_event_clock(event);
6110 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6111 data->id = primary_event_id(event);
6113 if (sample_type & PERF_SAMPLE_STREAM_ID)
6114 data->stream_id = event->id;
6116 if (sample_type & PERF_SAMPLE_CPU) {
6117 data->cpu_entry.cpu = raw_smp_processor_id();
6118 data->cpu_entry.reserved = 0;
6122 void perf_event_header__init_id(struct perf_event_header *header,
6123 struct perf_sample_data *data,
6124 struct perf_event *event)
6126 if (event->attr.sample_id_all)
6127 __perf_event_header__init_id(header, data, event);
6130 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6131 struct perf_sample_data *data)
6133 u64 sample_type = data->type;
6135 if (sample_type & PERF_SAMPLE_TID)
6136 perf_output_put(handle, data->tid_entry);
6138 if (sample_type & PERF_SAMPLE_TIME)
6139 perf_output_put(handle, data->time);
6141 if (sample_type & PERF_SAMPLE_ID)
6142 perf_output_put(handle, data->id);
6144 if (sample_type & PERF_SAMPLE_STREAM_ID)
6145 perf_output_put(handle, data->stream_id);
6147 if (sample_type & PERF_SAMPLE_CPU)
6148 perf_output_put(handle, data->cpu_entry);
6150 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6151 perf_output_put(handle, data->id);
6154 void perf_event__output_id_sample(struct perf_event *event,
6155 struct perf_output_handle *handle,
6156 struct perf_sample_data *sample)
6158 if (event->attr.sample_id_all)
6159 __perf_event__output_id_sample(handle, sample);
6162 static void perf_output_read_one(struct perf_output_handle *handle,
6163 struct perf_event *event,
6164 u64 enabled, u64 running)
6166 u64 read_format = event->attr.read_format;
6170 values[n++] = perf_event_count(event);
6171 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6172 values[n++] = enabled +
6173 atomic64_read(&event->child_total_time_enabled);
6175 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6176 values[n++] = running +
6177 atomic64_read(&event->child_total_time_running);
6179 if (read_format & PERF_FORMAT_ID)
6180 values[n++] = primary_event_id(event);
6182 __output_copy(handle, values, n * sizeof(u64));
6185 static void perf_output_read_group(struct perf_output_handle *handle,
6186 struct perf_event *event,
6187 u64 enabled, u64 running)
6189 struct perf_event *leader = event->group_leader, *sub;
6190 u64 read_format = event->attr.read_format;
6194 values[n++] = 1 + leader->nr_siblings;
6196 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6197 values[n++] = enabled;
6199 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6200 values[n++] = running;
6202 if ((leader != event) &&
6203 (leader->state == PERF_EVENT_STATE_ACTIVE))
6204 leader->pmu->read(leader);
6206 values[n++] = perf_event_count(leader);
6207 if (read_format & PERF_FORMAT_ID)
6208 values[n++] = primary_event_id(leader);
6210 __output_copy(handle, values, n * sizeof(u64));
6212 for_each_sibling_event(sub, leader) {
6215 if ((sub != event) &&
6216 (sub->state == PERF_EVENT_STATE_ACTIVE))
6217 sub->pmu->read(sub);
6219 values[n++] = perf_event_count(sub);
6220 if (read_format & PERF_FORMAT_ID)
6221 values[n++] = primary_event_id(sub);
6223 __output_copy(handle, values, n * sizeof(u64));
6227 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6228 PERF_FORMAT_TOTAL_TIME_RUNNING)
6231 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6233 * The problem is that its both hard and excessively expensive to iterate the
6234 * child list, not to mention that its impossible to IPI the children running
6235 * on another CPU, from interrupt/NMI context.
6237 static void perf_output_read(struct perf_output_handle *handle,
6238 struct perf_event *event)
6240 u64 enabled = 0, running = 0, now;
6241 u64 read_format = event->attr.read_format;
6244 * compute total_time_enabled, total_time_running
6245 * based on snapshot values taken when the event
6246 * was last scheduled in.
6248 * we cannot simply called update_context_time()
6249 * because of locking issue as we are called in
6252 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6253 calc_timer_values(event, &now, &enabled, &running);
6255 if (event->attr.read_format & PERF_FORMAT_GROUP)
6256 perf_output_read_group(handle, event, enabled, running);
6258 perf_output_read_one(handle, event, enabled, running);
6261 void perf_output_sample(struct perf_output_handle *handle,
6262 struct perf_event_header *header,
6263 struct perf_sample_data *data,
6264 struct perf_event *event)
6266 u64 sample_type = data->type;
6268 perf_output_put(handle, *header);
6270 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6271 perf_output_put(handle, data->id);
6273 if (sample_type & PERF_SAMPLE_IP)
6274 perf_output_put(handle, data->ip);
6276 if (sample_type & PERF_SAMPLE_TID)
6277 perf_output_put(handle, data->tid_entry);
6279 if (sample_type & PERF_SAMPLE_TIME)
6280 perf_output_put(handle, data->time);
6282 if (sample_type & PERF_SAMPLE_ADDR)
6283 perf_output_put(handle, data->addr);
6285 if (sample_type & PERF_SAMPLE_ID)
6286 perf_output_put(handle, data->id);
6288 if (sample_type & PERF_SAMPLE_STREAM_ID)
6289 perf_output_put(handle, data->stream_id);
6291 if (sample_type & PERF_SAMPLE_CPU)
6292 perf_output_put(handle, data->cpu_entry);
6294 if (sample_type & PERF_SAMPLE_PERIOD)
6295 perf_output_put(handle, data->period);
6297 if (sample_type & PERF_SAMPLE_READ)
6298 perf_output_read(handle, event);
6300 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6303 size += data->callchain->nr;
6304 size *= sizeof(u64);
6305 __output_copy(handle, data->callchain, size);
6308 if (sample_type & PERF_SAMPLE_RAW) {
6309 struct perf_raw_record *raw = data->raw;
6312 struct perf_raw_frag *frag = &raw->frag;
6314 perf_output_put(handle, raw->size);
6317 __output_custom(handle, frag->copy,
6318 frag->data, frag->size);
6320 __output_copy(handle, frag->data,
6323 if (perf_raw_frag_last(frag))
6328 __output_skip(handle, NULL, frag->pad);
6334 .size = sizeof(u32),
6337 perf_output_put(handle, raw);
6341 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6342 if (data->br_stack) {
6345 size = data->br_stack->nr
6346 * sizeof(struct perf_branch_entry);
6348 perf_output_put(handle, data->br_stack->nr);
6349 perf_output_copy(handle, data->br_stack->entries, size);
6352 * we always store at least the value of nr
6355 perf_output_put(handle, nr);
6359 if (sample_type & PERF_SAMPLE_REGS_USER) {
6360 u64 abi = data->regs_user.abi;
6363 * If there are no regs to dump, notice it through
6364 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6366 perf_output_put(handle, abi);
6369 u64 mask = event->attr.sample_regs_user;
6370 perf_output_sample_regs(handle,
6371 data->regs_user.regs,
6376 if (sample_type & PERF_SAMPLE_STACK_USER) {
6377 perf_output_sample_ustack(handle,
6378 data->stack_user_size,
6379 data->regs_user.regs);
6382 if (sample_type & PERF_SAMPLE_WEIGHT)
6383 perf_output_put(handle, data->weight);
6385 if (sample_type & PERF_SAMPLE_DATA_SRC)
6386 perf_output_put(handle, data->data_src.val);
6388 if (sample_type & PERF_SAMPLE_TRANSACTION)
6389 perf_output_put(handle, data->txn);
6391 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6392 u64 abi = data->regs_intr.abi;
6394 * If there are no regs to dump, notice it through
6395 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6397 perf_output_put(handle, abi);
6400 u64 mask = event->attr.sample_regs_intr;
6402 perf_output_sample_regs(handle,
6403 data->regs_intr.regs,
6408 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6409 perf_output_put(handle, data->phys_addr);
6411 if (!event->attr.watermark) {
6412 int wakeup_events = event->attr.wakeup_events;
6414 if (wakeup_events) {
6415 struct ring_buffer *rb = handle->rb;
6416 int events = local_inc_return(&rb->events);
6418 if (events >= wakeup_events) {
6419 local_sub(wakeup_events, &rb->events);
6420 local_inc(&rb->wakeup);
6426 static u64 perf_virt_to_phys(u64 virt)
6429 struct page *p = NULL;
6434 if (virt >= TASK_SIZE) {
6435 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6436 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6437 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6438 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6441 * Walking the pages tables for user address.
6442 * Interrupts are disabled, so it prevents any tear down
6443 * of the page tables.
6444 * Try IRQ-safe __get_user_pages_fast first.
6445 * If failed, leave phys_addr as 0.
6447 if (current->mm != NULL) {
6448 pagefault_disable();
6449 if (__get_user_pages_fast(virt, 1, 0, &p) == 1)
6450 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6461 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6463 struct perf_callchain_entry *
6464 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6466 bool kernel = !event->attr.exclude_callchain_kernel;
6467 bool user = !event->attr.exclude_callchain_user;
6468 /* Disallow cross-task user callchains. */
6469 bool crosstask = event->ctx->task && event->ctx->task != current;
6470 const u32 max_stack = event->attr.sample_max_stack;
6471 struct perf_callchain_entry *callchain;
6473 if (!kernel && !user)
6474 return &__empty_callchain;
6476 callchain = get_perf_callchain(regs, 0, kernel, user,
6477 max_stack, crosstask, true);
6478 return callchain ?: &__empty_callchain;
6481 void perf_prepare_sample(struct perf_event_header *header,
6482 struct perf_sample_data *data,
6483 struct perf_event *event,
6484 struct pt_regs *regs)
6486 u64 sample_type = event->attr.sample_type;
6488 header->type = PERF_RECORD_SAMPLE;
6489 header->size = sizeof(*header) + event->header_size;
6492 header->misc |= perf_misc_flags(regs);
6494 __perf_event_header__init_id(header, data, event);
6496 if (sample_type & PERF_SAMPLE_IP)
6497 data->ip = perf_instruction_pointer(regs);
6499 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6502 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6503 data->callchain = perf_callchain(event, regs);
6505 size += data->callchain->nr;
6507 header->size += size * sizeof(u64);
6510 if (sample_type & PERF_SAMPLE_RAW) {
6511 struct perf_raw_record *raw = data->raw;
6515 struct perf_raw_frag *frag = &raw->frag;
6520 if (perf_raw_frag_last(frag))
6525 size = round_up(sum + sizeof(u32), sizeof(u64));
6526 raw->size = size - sizeof(u32);
6527 frag->pad = raw->size - sum;
6532 header->size += size;
6535 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6536 int size = sizeof(u64); /* nr */
6537 if (data->br_stack) {
6538 size += data->br_stack->nr
6539 * sizeof(struct perf_branch_entry);
6541 header->size += size;
6544 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6545 perf_sample_regs_user(&data->regs_user, regs,
6546 &data->regs_user_copy);
6548 if (sample_type & PERF_SAMPLE_REGS_USER) {
6549 /* regs dump ABI info */
6550 int size = sizeof(u64);
6552 if (data->regs_user.regs) {
6553 u64 mask = event->attr.sample_regs_user;
6554 size += hweight64(mask) * sizeof(u64);
6557 header->size += size;
6560 if (sample_type & PERF_SAMPLE_STACK_USER) {
6562 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6563 * processed as the last one or have additional check added
6564 * in case new sample type is added, because we could eat
6565 * up the rest of the sample size.
6567 u16 stack_size = event->attr.sample_stack_user;
6568 u16 size = sizeof(u64);
6570 stack_size = perf_sample_ustack_size(stack_size, header->size,
6571 data->regs_user.regs);
6574 * If there is something to dump, add space for the dump
6575 * itself and for the field that tells the dynamic size,
6576 * which is how many have been actually dumped.
6579 size += sizeof(u64) + stack_size;
6581 data->stack_user_size = stack_size;
6582 header->size += size;
6585 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6586 /* regs dump ABI info */
6587 int size = sizeof(u64);
6589 perf_sample_regs_intr(&data->regs_intr, regs);
6591 if (data->regs_intr.regs) {
6592 u64 mask = event->attr.sample_regs_intr;
6594 size += hweight64(mask) * sizeof(u64);
6597 header->size += size;
6600 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6601 data->phys_addr = perf_virt_to_phys(data->addr);
6604 static __always_inline void
6605 __perf_event_output(struct perf_event *event,
6606 struct perf_sample_data *data,
6607 struct pt_regs *regs,
6608 int (*output_begin)(struct perf_output_handle *,
6609 struct perf_event *,
6612 struct perf_output_handle handle;
6613 struct perf_event_header header;
6615 /* protect the callchain buffers */
6618 perf_prepare_sample(&header, data, event, regs);
6620 if (output_begin(&handle, event, header.size))
6623 perf_output_sample(&handle, &header, data, event);
6625 perf_output_end(&handle);
6632 perf_event_output_forward(struct perf_event *event,
6633 struct perf_sample_data *data,
6634 struct pt_regs *regs)
6636 __perf_event_output(event, data, regs, perf_output_begin_forward);
6640 perf_event_output_backward(struct perf_event *event,
6641 struct perf_sample_data *data,
6642 struct pt_regs *regs)
6644 __perf_event_output(event, data, regs, perf_output_begin_backward);
6648 perf_event_output(struct perf_event *event,
6649 struct perf_sample_data *data,
6650 struct pt_regs *regs)
6652 __perf_event_output(event, data, regs, perf_output_begin);
6659 struct perf_read_event {
6660 struct perf_event_header header;
6667 perf_event_read_event(struct perf_event *event,
6668 struct task_struct *task)
6670 struct perf_output_handle handle;
6671 struct perf_sample_data sample;
6672 struct perf_read_event read_event = {
6674 .type = PERF_RECORD_READ,
6676 .size = sizeof(read_event) + event->read_size,
6678 .pid = perf_event_pid(event, task),
6679 .tid = perf_event_tid(event, task),
6683 perf_event_header__init_id(&read_event.header, &sample, event);
6684 ret = perf_output_begin(&handle, event, read_event.header.size);
6688 perf_output_put(&handle, read_event);
6689 perf_output_read(&handle, event);
6690 perf_event__output_id_sample(event, &handle, &sample);
6692 perf_output_end(&handle);
6695 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6698 perf_iterate_ctx(struct perf_event_context *ctx,
6699 perf_iterate_f output,
6700 void *data, bool all)
6702 struct perf_event *event;
6704 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6706 if (event->state < PERF_EVENT_STATE_INACTIVE)
6708 if (!event_filter_match(event))
6712 output(event, data);
6716 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6718 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6719 struct perf_event *event;
6721 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6723 * Skip events that are not fully formed yet; ensure that
6724 * if we observe event->ctx, both event and ctx will be
6725 * complete enough. See perf_install_in_context().
6727 if (!smp_load_acquire(&event->ctx))
6730 if (event->state < PERF_EVENT_STATE_INACTIVE)
6732 if (!event_filter_match(event))
6734 output(event, data);
6739 * Iterate all events that need to receive side-band events.
6741 * For new callers; ensure that account_pmu_sb_event() includes
6742 * your event, otherwise it might not get delivered.
6745 perf_iterate_sb(perf_iterate_f output, void *data,
6746 struct perf_event_context *task_ctx)
6748 struct perf_event_context *ctx;
6755 * If we have task_ctx != NULL we only notify the task context itself.
6756 * The task_ctx is set only for EXIT events before releasing task
6760 perf_iterate_ctx(task_ctx, output, data, false);
6764 perf_iterate_sb_cpu(output, data);
6766 for_each_task_context_nr(ctxn) {
6767 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6769 perf_iterate_ctx(ctx, output, data, false);
6777 * Clear all file-based filters at exec, they'll have to be
6778 * re-instated when/if these objects are mmapped again.
6780 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6782 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6783 struct perf_addr_filter *filter;
6784 unsigned int restart = 0, count = 0;
6785 unsigned long flags;
6787 if (!has_addr_filter(event))
6790 raw_spin_lock_irqsave(&ifh->lock, flags);
6791 list_for_each_entry(filter, &ifh->list, entry) {
6792 if (filter->path.dentry) {
6793 event->addr_filter_ranges[count].start = 0;
6794 event->addr_filter_ranges[count].size = 0;
6802 event->addr_filters_gen++;
6803 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6806 perf_event_stop(event, 1);
6809 void perf_event_exec(void)
6811 struct perf_event_context *ctx;
6815 for_each_task_context_nr(ctxn) {
6816 ctx = current->perf_event_ctxp[ctxn];
6820 perf_event_enable_on_exec(ctxn);
6822 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6828 struct remote_output {
6829 struct ring_buffer *rb;
6833 static void __perf_event_output_stop(struct perf_event *event, void *data)
6835 struct perf_event *parent = event->parent;
6836 struct remote_output *ro = data;
6837 struct ring_buffer *rb = ro->rb;
6838 struct stop_event_data sd = {
6842 if (!has_aux(event))
6849 * In case of inheritance, it will be the parent that links to the
6850 * ring-buffer, but it will be the child that's actually using it.
6852 * We are using event::rb to determine if the event should be stopped,
6853 * however this may race with ring_buffer_attach() (through set_output),
6854 * which will make us skip the event that actually needs to be stopped.
6855 * So ring_buffer_attach() has to stop an aux event before re-assigning
6858 if (rcu_dereference(parent->rb) == rb)
6859 ro->err = __perf_event_stop(&sd);
6862 static int __perf_pmu_output_stop(void *info)
6864 struct perf_event *event = info;
6865 struct pmu *pmu = event->ctx->pmu;
6866 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6867 struct remote_output ro = {
6872 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6873 if (cpuctx->task_ctx)
6874 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6881 static void perf_pmu_output_stop(struct perf_event *event)
6883 struct perf_event *iter;
6888 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6890 * For per-CPU events, we need to make sure that neither they
6891 * nor their children are running; for cpu==-1 events it's
6892 * sufficient to stop the event itself if it's active, since
6893 * it can't have children.
6897 cpu = READ_ONCE(iter->oncpu);
6902 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6903 if (err == -EAGAIN) {
6912 * task tracking -- fork/exit
6914 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6917 struct perf_task_event {
6918 struct task_struct *task;
6919 struct perf_event_context *task_ctx;
6922 struct perf_event_header header;
6932 static int perf_event_task_match(struct perf_event *event)
6934 return event->attr.comm || event->attr.mmap ||
6935 event->attr.mmap2 || event->attr.mmap_data ||
6939 static void perf_event_task_output(struct perf_event *event,
6942 struct perf_task_event *task_event = data;
6943 struct perf_output_handle handle;
6944 struct perf_sample_data sample;
6945 struct task_struct *task = task_event->task;
6946 int ret, size = task_event->event_id.header.size;
6948 if (!perf_event_task_match(event))
6951 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6953 ret = perf_output_begin(&handle, event,
6954 task_event->event_id.header.size);
6958 task_event->event_id.pid = perf_event_pid(event, task);
6959 task_event->event_id.tid = perf_event_tid(event, task);
6961 if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
6962 task_event->event_id.ppid = perf_event_pid(event,
6964 task_event->event_id.ptid = perf_event_pid(event,
6966 } else { /* PERF_RECORD_FORK */
6967 task_event->event_id.ppid = perf_event_pid(event, current);
6968 task_event->event_id.ptid = perf_event_tid(event, current);
6971 task_event->event_id.time = perf_event_clock(event);
6973 perf_output_put(&handle, task_event->event_id);
6975 perf_event__output_id_sample(event, &handle, &sample);
6977 perf_output_end(&handle);
6979 task_event->event_id.header.size = size;
6982 static void perf_event_task(struct task_struct *task,
6983 struct perf_event_context *task_ctx,
6986 struct perf_task_event task_event;
6988 if (!atomic_read(&nr_comm_events) &&
6989 !atomic_read(&nr_mmap_events) &&
6990 !atomic_read(&nr_task_events))
6993 task_event = (struct perf_task_event){
6995 .task_ctx = task_ctx,
6998 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7000 .size = sizeof(task_event.event_id),
7010 perf_iterate_sb(perf_event_task_output,
7015 void perf_event_fork(struct task_struct *task)
7017 perf_event_task(task, NULL, 1);
7018 perf_event_namespaces(task);
7025 struct perf_comm_event {
7026 struct task_struct *task;
7031 struct perf_event_header header;
7038 static int perf_event_comm_match(struct perf_event *event)
7040 return event->attr.comm;
7043 static void perf_event_comm_output(struct perf_event *event,
7046 struct perf_comm_event *comm_event = data;
7047 struct perf_output_handle handle;
7048 struct perf_sample_data sample;
7049 int size = comm_event->event_id.header.size;
7052 if (!perf_event_comm_match(event))
7055 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7056 ret = perf_output_begin(&handle, event,
7057 comm_event->event_id.header.size);
7062 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7063 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7065 perf_output_put(&handle, comm_event->event_id);
7066 __output_copy(&handle, comm_event->comm,
7067 comm_event->comm_size);
7069 perf_event__output_id_sample(event, &handle, &sample);
7071 perf_output_end(&handle);
7073 comm_event->event_id.header.size = size;
7076 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7078 char comm[TASK_COMM_LEN];
7081 memset(comm, 0, sizeof(comm));
7082 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7083 size = ALIGN(strlen(comm)+1, sizeof(u64));
7085 comm_event->comm = comm;
7086 comm_event->comm_size = size;
7088 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7090 perf_iterate_sb(perf_event_comm_output,
7095 void perf_event_comm(struct task_struct *task, bool exec)
7097 struct perf_comm_event comm_event;
7099 if (!atomic_read(&nr_comm_events))
7102 comm_event = (struct perf_comm_event){
7108 .type = PERF_RECORD_COMM,
7109 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7117 perf_event_comm_event(&comm_event);
7121 * namespaces tracking
7124 struct perf_namespaces_event {
7125 struct task_struct *task;
7128 struct perf_event_header header;
7133 struct perf_ns_link_info link_info[NR_NAMESPACES];
7137 static int perf_event_namespaces_match(struct perf_event *event)
7139 return event->attr.namespaces;
7142 static void perf_event_namespaces_output(struct perf_event *event,
7145 struct perf_namespaces_event *namespaces_event = data;
7146 struct perf_output_handle handle;
7147 struct perf_sample_data sample;
7148 u16 header_size = namespaces_event->event_id.header.size;
7151 if (!perf_event_namespaces_match(event))
7154 perf_event_header__init_id(&namespaces_event->event_id.header,
7156 ret = perf_output_begin(&handle, event,
7157 namespaces_event->event_id.header.size);
7161 namespaces_event->event_id.pid = perf_event_pid(event,
7162 namespaces_event->task);
7163 namespaces_event->event_id.tid = perf_event_tid(event,
7164 namespaces_event->task);
7166 perf_output_put(&handle, namespaces_event->event_id);
7168 perf_event__output_id_sample(event, &handle, &sample);
7170 perf_output_end(&handle);
7172 namespaces_event->event_id.header.size = header_size;
7175 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7176 struct task_struct *task,
7177 const struct proc_ns_operations *ns_ops)
7179 struct path ns_path;
7180 struct inode *ns_inode;
7183 error = ns_get_path(&ns_path, task, ns_ops);
7185 ns_inode = ns_path.dentry->d_inode;
7186 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7187 ns_link_info->ino = ns_inode->i_ino;
7192 void perf_event_namespaces(struct task_struct *task)
7194 struct perf_namespaces_event namespaces_event;
7195 struct perf_ns_link_info *ns_link_info;
7197 if (!atomic_read(&nr_namespaces_events))
7200 namespaces_event = (struct perf_namespaces_event){
7204 .type = PERF_RECORD_NAMESPACES,
7206 .size = sizeof(namespaces_event.event_id),
7210 .nr_namespaces = NR_NAMESPACES,
7211 /* .link_info[NR_NAMESPACES] */
7215 ns_link_info = namespaces_event.event_id.link_info;
7217 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7218 task, &mntns_operations);
7220 #ifdef CONFIG_USER_NS
7221 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7222 task, &userns_operations);
7224 #ifdef CONFIG_NET_NS
7225 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7226 task, &netns_operations);
7228 #ifdef CONFIG_UTS_NS
7229 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7230 task, &utsns_operations);
7232 #ifdef CONFIG_IPC_NS
7233 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7234 task, &ipcns_operations);
7236 #ifdef CONFIG_PID_NS
7237 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7238 task, &pidns_operations);
7240 #ifdef CONFIG_CGROUPS
7241 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7242 task, &cgroupns_operations);
7245 perf_iterate_sb(perf_event_namespaces_output,
7254 struct perf_mmap_event {
7255 struct vm_area_struct *vma;
7257 const char *file_name;
7265 struct perf_event_header header;
7275 static int perf_event_mmap_match(struct perf_event *event,
7278 struct perf_mmap_event *mmap_event = data;
7279 struct vm_area_struct *vma = mmap_event->vma;
7280 int executable = vma->vm_flags & VM_EXEC;
7282 return (!executable && event->attr.mmap_data) ||
7283 (executable && (event->attr.mmap || event->attr.mmap2));
7286 static void perf_event_mmap_output(struct perf_event *event,
7289 struct perf_mmap_event *mmap_event = data;
7290 struct perf_output_handle handle;
7291 struct perf_sample_data sample;
7292 int size = mmap_event->event_id.header.size;
7293 u32 type = mmap_event->event_id.header.type;
7296 if (!perf_event_mmap_match(event, data))
7299 if (event->attr.mmap2) {
7300 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7301 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7302 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7303 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7304 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7305 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7306 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7309 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7310 ret = perf_output_begin(&handle, event,
7311 mmap_event->event_id.header.size);
7315 mmap_event->event_id.pid = perf_event_pid(event, current);
7316 mmap_event->event_id.tid = perf_event_tid(event, current);
7318 perf_output_put(&handle, mmap_event->event_id);
7320 if (event->attr.mmap2) {
7321 perf_output_put(&handle, mmap_event->maj);
7322 perf_output_put(&handle, mmap_event->min);
7323 perf_output_put(&handle, mmap_event->ino);
7324 perf_output_put(&handle, mmap_event->ino_generation);
7325 perf_output_put(&handle, mmap_event->prot);
7326 perf_output_put(&handle, mmap_event->flags);
7329 __output_copy(&handle, mmap_event->file_name,
7330 mmap_event->file_size);
7332 perf_event__output_id_sample(event, &handle, &sample);
7334 perf_output_end(&handle);
7336 mmap_event->event_id.header.size = size;
7337 mmap_event->event_id.header.type = type;
7340 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7342 struct vm_area_struct *vma = mmap_event->vma;
7343 struct file *file = vma->vm_file;
7344 int maj = 0, min = 0;
7345 u64 ino = 0, gen = 0;
7346 u32 prot = 0, flags = 0;
7352 if (vma->vm_flags & VM_READ)
7354 if (vma->vm_flags & VM_WRITE)
7356 if (vma->vm_flags & VM_EXEC)
7359 if (vma->vm_flags & VM_MAYSHARE)
7362 flags = MAP_PRIVATE;
7364 if (vma->vm_flags & VM_DENYWRITE)
7365 flags |= MAP_DENYWRITE;
7366 if (vma->vm_flags & VM_MAYEXEC)
7367 flags |= MAP_EXECUTABLE;
7368 if (vma->vm_flags & VM_LOCKED)
7369 flags |= MAP_LOCKED;
7370 if (vma->vm_flags & VM_HUGETLB)
7371 flags |= MAP_HUGETLB;
7374 struct inode *inode;
7377 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7383 * d_path() works from the end of the rb backwards, so we
7384 * need to add enough zero bytes after the string to handle
7385 * the 64bit alignment we do later.
7387 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7392 inode = file_inode(vma->vm_file);
7393 dev = inode->i_sb->s_dev;
7395 gen = inode->i_generation;
7401 if (vma->vm_ops && vma->vm_ops->name) {
7402 name = (char *) vma->vm_ops->name(vma);
7407 name = (char *)arch_vma_name(vma);
7411 if (vma->vm_start <= vma->vm_mm->start_brk &&
7412 vma->vm_end >= vma->vm_mm->brk) {
7416 if (vma->vm_start <= vma->vm_mm->start_stack &&
7417 vma->vm_end >= vma->vm_mm->start_stack) {
7427 strlcpy(tmp, name, sizeof(tmp));
7431 * Since our buffer works in 8 byte units we need to align our string
7432 * size to a multiple of 8. However, we must guarantee the tail end is
7433 * zero'd out to avoid leaking random bits to userspace.
7435 size = strlen(name)+1;
7436 while (!IS_ALIGNED(size, sizeof(u64)))
7437 name[size++] = '\0';
7439 mmap_event->file_name = name;
7440 mmap_event->file_size = size;
7441 mmap_event->maj = maj;
7442 mmap_event->min = min;
7443 mmap_event->ino = ino;
7444 mmap_event->ino_generation = gen;
7445 mmap_event->prot = prot;
7446 mmap_event->flags = flags;
7448 if (!(vma->vm_flags & VM_EXEC))
7449 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7451 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7453 perf_iterate_sb(perf_event_mmap_output,
7461 * Check whether inode and address range match filter criteria.
7463 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7464 struct file *file, unsigned long offset,
7467 /* d_inode(NULL) won't be equal to any mapped user-space file */
7468 if (!filter->path.dentry)
7471 if (d_inode(filter->path.dentry) != file_inode(file))
7474 if (filter->offset > offset + size)
7477 if (filter->offset + filter->size < offset)
7483 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
7484 struct vm_area_struct *vma,
7485 struct perf_addr_filter_range *fr)
7487 unsigned long vma_size = vma->vm_end - vma->vm_start;
7488 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7489 struct file *file = vma->vm_file;
7491 if (!perf_addr_filter_match(filter, file, off, vma_size))
7494 if (filter->offset < off) {
7495 fr->start = vma->vm_start;
7496 fr->size = min(vma_size, filter->size - (off - filter->offset));
7498 fr->start = vma->vm_start + filter->offset - off;
7499 fr->size = min(vma->vm_end - fr->start, filter->size);
7505 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7507 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7508 struct vm_area_struct *vma = data;
7509 struct perf_addr_filter *filter;
7510 unsigned int restart = 0, count = 0;
7511 unsigned long flags;
7513 if (!has_addr_filter(event))
7519 raw_spin_lock_irqsave(&ifh->lock, flags);
7520 list_for_each_entry(filter, &ifh->list, entry) {
7521 if (perf_addr_filter_vma_adjust(filter, vma,
7522 &event->addr_filter_ranges[count]))
7529 event->addr_filters_gen++;
7530 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7533 perf_event_stop(event, 1);
7537 * Adjust all task's events' filters to the new vma
7539 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7541 struct perf_event_context *ctx;
7545 * Data tracing isn't supported yet and as such there is no need
7546 * to keep track of anything that isn't related to executable code:
7548 if (!(vma->vm_flags & VM_EXEC))
7552 for_each_task_context_nr(ctxn) {
7553 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7557 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7562 void perf_event_mmap(struct vm_area_struct *vma)
7564 struct perf_mmap_event mmap_event;
7566 if (!atomic_read(&nr_mmap_events))
7569 mmap_event = (struct perf_mmap_event){
7575 .type = PERF_RECORD_MMAP,
7576 .misc = PERF_RECORD_MISC_USER,
7581 .start = vma->vm_start,
7582 .len = vma->vm_end - vma->vm_start,
7583 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7585 /* .maj (attr_mmap2 only) */
7586 /* .min (attr_mmap2 only) */
7587 /* .ino (attr_mmap2 only) */
7588 /* .ino_generation (attr_mmap2 only) */
7589 /* .prot (attr_mmap2 only) */
7590 /* .flags (attr_mmap2 only) */
7593 perf_addr_filters_adjust(vma);
7594 perf_event_mmap_event(&mmap_event);
7597 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7598 unsigned long size, u64 flags)
7600 struct perf_output_handle handle;
7601 struct perf_sample_data sample;
7602 struct perf_aux_event {
7603 struct perf_event_header header;
7609 .type = PERF_RECORD_AUX,
7611 .size = sizeof(rec),
7619 perf_event_header__init_id(&rec.header, &sample, event);
7620 ret = perf_output_begin(&handle, event, rec.header.size);
7625 perf_output_put(&handle, rec);
7626 perf_event__output_id_sample(event, &handle, &sample);
7628 perf_output_end(&handle);
7632 * Lost/dropped samples logging
7634 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7636 struct perf_output_handle handle;
7637 struct perf_sample_data sample;
7641 struct perf_event_header header;
7643 } lost_samples_event = {
7645 .type = PERF_RECORD_LOST_SAMPLES,
7647 .size = sizeof(lost_samples_event),
7652 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7654 ret = perf_output_begin(&handle, event,
7655 lost_samples_event.header.size);
7659 perf_output_put(&handle, lost_samples_event);
7660 perf_event__output_id_sample(event, &handle, &sample);
7661 perf_output_end(&handle);
7665 * context_switch tracking
7668 struct perf_switch_event {
7669 struct task_struct *task;
7670 struct task_struct *next_prev;
7673 struct perf_event_header header;
7679 static int perf_event_switch_match(struct perf_event *event)
7681 return event->attr.context_switch;
7684 static void perf_event_switch_output(struct perf_event *event, void *data)
7686 struct perf_switch_event *se = data;
7687 struct perf_output_handle handle;
7688 struct perf_sample_data sample;
7691 if (!perf_event_switch_match(event))
7694 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7695 if (event->ctx->task) {
7696 se->event_id.header.type = PERF_RECORD_SWITCH;
7697 se->event_id.header.size = sizeof(se->event_id.header);
7699 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7700 se->event_id.header.size = sizeof(se->event_id);
7701 se->event_id.next_prev_pid =
7702 perf_event_pid(event, se->next_prev);
7703 se->event_id.next_prev_tid =
7704 perf_event_tid(event, se->next_prev);
7707 perf_event_header__init_id(&se->event_id.header, &sample, event);
7709 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7713 if (event->ctx->task)
7714 perf_output_put(&handle, se->event_id.header);
7716 perf_output_put(&handle, se->event_id);
7718 perf_event__output_id_sample(event, &handle, &sample);
7720 perf_output_end(&handle);
7723 static void perf_event_switch(struct task_struct *task,
7724 struct task_struct *next_prev, bool sched_in)
7726 struct perf_switch_event switch_event;
7728 /* N.B. caller checks nr_switch_events != 0 */
7730 switch_event = (struct perf_switch_event){
7732 .next_prev = next_prev,
7736 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7739 /* .next_prev_pid */
7740 /* .next_prev_tid */
7744 if (!sched_in && task->state == TASK_RUNNING)
7745 switch_event.event_id.header.misc |=
7746 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
7748 perf_iterate_sb(perf_event_switch_output,
7754 * IRQ throttle logging
7757 static void perf_log_throttle(struct perf_event *event, int enable)
7759 struct perf_output_handle handle;
7760 struct perf_sample_data sample;
7764 struct perf_event_header header;
7768 } throttle_event = {
7770 .type = PERF_RECORD_THROTTLE,
7772 .size = sizeof(throttle_event),
7774 .time = perf_event_clock(event),
7775 .id = primary_event_id(event),
7776 .stream_id = event->id,
7780 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7782 perf_event_header__init_id(&throttle_event.header, &sample, event);
7784 ret = perf_output_begin(&handle, event,
7785 throttle_event.header.size);
7789 perf_output_put(&handle, throttle_event);
7790 perf_event__output_id_sample(event, &handle, &sample);
7791 perf_output_end(&handle);
7794 void perf_event_itrace_started(struct perf_event *event)
7796 event->attach_state |= PERF_ATTACH_ITRACE;
7799 static void perf_log_itrace_start(struct perf_event *event)
7801 struct perf_output_handle handle;
7802 struct perf_sample_data sample;
7803 struct perf_aux_event {
7804 struct perf_event_header header;
7811 event = event->parent;
7813 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7814 event->attach_state & PERF_ATTACH_ITRACE)
7817 rec.header.type = PERF_RECORD_ITRACE_START;
7818 rec.header.misc = 0;
7819 rec.header.size = sizeof(rec);
7820 rec.pid = perf_event_pid(event, current);
7821 rec.tid = perf_event_tid(event, current);
7823 perf_event_header__init_id(&rec.header, &sample, event);
7824 ret = perf_output_begin(&handle, event, rec.header.size);
7829 perf_output_put(&handle, rec);
7830 perf_event__output_id_sample(event, &handle, &sample);
7832 perf_output_end(&handle);
7836 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7838 struct hw_perf_event *hwc = &event->hw;
7842 seq = __this_cpu_read(perf_throttled_seq);
7843 if (seq != hwc->interrupts_seq) {
7844 hwc->interrupts_seq = seq;
7845 hwc->interrupts = 1;
7848 if (unlikely(throttle
7849 && hwc->interrupts >= max_samples_per_tick)) {
7850 __this_cpu_inc(perf_throttled_count);
7851 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7852 hwc->interrupts = MAX_INTERRUPTS;
7853 perf_log_throttle(event, 0);
7858 if (event->attr.freq) {
7859 u64 now = perf_clock();
7860 s64 delta = now - hwc->freq_time_stamp;
7862 hwc->freq_time_stamp = now;
7864 if (delta > 0 && delta < 2*TICK_NSEC)
7865 perf_adjust_period(event, delta, hwc->last_period, true);
7871 int perf_event_account_interrupt(struct perf_event *event)
7873 return __perf_event_account_interrupt(event, 1);
7877 * Generic event overflow handling, sampling.
7880 static int __perf_event_overflow(struct perf_event *event,
7881 int throttle, struct perf_sample_data *data,
7882 struct pt_regs *regs)
7884 int events = atomic_read(&event->event_limit);
7888 * Non-sampling counters might still use the PMI to fold short
7889 * hardware counters, ignore those.
7891 if (unlikely(!is_sampling_event(event)))
7894 ret = __perf_event_account_interrupt(event, throttle);
7897 * XXX event_limit might not quite work as expected on inherited
7901 event->pending_kill = POLL_IN;
7902 if (events && atomic_dec_and_test(&event->event_limit)) {
7904 event->pending_kill = POLL_HUP;
7906 perf_event_disable_inatomic(event);
7909 READ_ONCE(event->overflow_handler)(event, data, regs);
7911 if (*perf_event_fasync(event) && event->pending_kill) {
7912 event->pending_wakeup = 1;
7913 irq_work_queue(&event->pending);
7919 int perf_event_overflow(struct perf_event *event,
7920 struct perf_sample_data *data,
7921 struct pt_regs *regs)
7923 return __perf_event_overflow(event, 1, data, regs);
7927 * Generic software event infrastructure
7930 struct swevent_htable {
7931 struct swevent_hlist *swevent_hlist;
7932 struct mutex hlist_mutex;
7935 /* Recursion avoidance in each contexts */
7936 int recursion[PERF_NR_CONTEXTS];
7939 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7942 * We directly increment event->count and keep a second value in
7943 * event->hw.period_left to count intervals. This period event
7944 * is kept in the range [-sample_period, 0] so that we can use the
7948 u64 perf_swevent_set_period(struct perf_event *event)
7950 struct hw_perf_event *hwc = &event->hw;
7951 u64 period = hwc->last_period;
7955 hwc->last_period = hwc->sample_period;
7958 old = val = local64_read(&hwc->period_left);
7962 nr = div64_u64(period + val, period);
7963 offset = nr * period;
7965 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7971 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7972 struct perf_sample_data *data,
7973 struct pt_regs *regs)
7975 struct hw_perf_event *hwc = &event->hw;
7979 overflow = perf_swevent_set_period(event);
7981 if (hwc->interrupts == MAX_INTERRUPTS)
7984 for (; overflow; overflow--) {
7985 if (__perf_event_overflow(event, throttle,
7988 * We inhibit the overflow from happening when
7989 * hwc->interrupts == MAX_INTERRUPTS.
7997 static void perf_swevent_event(struct perf_event *event, u64 nr,
7998 struct perf_sample_data *data,
7999 struct pt_regs *regs)
8001 struct hw_perf_event *hwc = &event->hw;
8003 local64_add(nr, &event->count);
8008 if (!is_sampling_event(event))
8011 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
8013 return perf_swevent_overflow(event, 1, data, regs);
8015 data->period = event->hw.last_period;
8017 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
8018 return perf_swevent_overflow(event, 1, data, regs);
8020 if (local64_add_negative(nr, &hwc->period_left))
8023 perf_swevent_overflow(event, 0, data, regs);
8026 static int perf_exclude_event(struct perf_event *event,
8027 struct pt_regs *regs)
8029 if (event->hw.state & PERF_HES_STOPPED)
8033 if (event->attr.exclude_user && user_mode(regs))
8036 if (event->attr.exclude_kernel && !user_mode(regs))
8043 static int perf_swevent_match(struct perf_event *event,
8044 enum perf_type_id type,
8046 struct perf_sample_data *data,
8047 struct pt_regs *regs)
8049 if (event->attr.type != type)
8052 if (event->attr.config != event_id)
8055 if (perf_exclude_event(event, regs))
8061 static inline u64 swevent_hash(u64 type, u32 event_id)
8063 u64 val = event_id | (type << 32);
8065 return hash_64(val, SWEVENT_HLIST_BITS);
8068 static inline struct hlist_head *
8069 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
8071 u64 hash = swevent_hash(type, event_id);
8073 return &hlist->heads[hash];
8076 /* For the read side: events when they trigger */
8077 static inline struct hlist_head *
8078 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8080 struct swevent_hlist *hlist;
8082 hlist = rcu_dereference(swhash->swevent_hlist);
8086 return __find_swevent_head(hlist, type, event_id);
8089 /* For the event head insertion and removal in the hlist */
8090 static inline struct hlist_head *
8091 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8093 struct swevent_hlist *hlist;
8094 u32 event_id = event->attr.config;
8095 u64 type = event->attr.type;
8098 * Event scheduling is always serialized against hlist allocation
8099 * and release. Which makes the protected version suitable here.
8100 * The context lock guarantees that.
8102 hlist = rcu_dereference_protected(swhash->swevent_hlist,
8103 lockdep_is_held(&event->ctx->lock));
8107 return __find_swevent_head(hlist, type, event_id);
8110 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8112 struct perf_sample_data *data,
8113 struct pt_regs *regs)
8115 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8116 struct perf_event *event;
8117 struct hlist_head *head;
8120 head = find_swevent_head_rcu(swhash, type, event_id);
8124 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8125 if (perf_swevent_match(event, type, event_id, data, regs))
8126 perf_swevent_event(event, nr, data, regs);
8132 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8134 int perf_swevent_get_recursion_context(void)
8136 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8138 return get_recursion_context(swhash->recursion);
8140 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8142 void perf_swevent_put_recursion_context(int rctx)
8144 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8146 put_recursion_context(swhash->recursion, rctx);
8149 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8151 struct perf_sample_data data;
8153 if (WARN_ON_ONCE(!regs))
8156 perf_sample_data_init(&data, addr, 0);
8157 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8160 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8164 preempt_disable_notrace();
8165 rctx = perf_swevent_get_recursion_context();
8166 if (unlikely(rctx < 0))
8169 ___perf_sw_event(event_id, nr, regs, addr);
8171 perf_swevent_put_recursion_context(rctx);
8173 preempt_enable_notrace();
8176 static void perf_swevent_read(struct perf_event *event)
8180 static int perf_swevent_add(struct perf_event *event, int flags)
8182 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8183 struct hw_perf_event *hwc = &event->hw;
8184 struct hlist_head *head;
8186 if (is_sampling_event(event)) {
8187 hwc->last_period = hwc->sample_period;
8188 perf_swevent_set_period(event);
8191 hwc->state = !(flags & PERF_EF_START);
8193 head = find_swevent_head(swhash, event);
8194 if (WARN_ON_ONCE(!head))
8197 hlist_add_head_rcu(&event->hlist_entry, head);
8198 perf_event_update_userpage(event);
8203 static void perf_swevent_del(struct perf_event *event, int flags)
8205 hlist_del_rcu(&event->hlist_entry);
8208 static void perf_swevent_start(struct perf_event *event, int flags)
8210 event->hw.state = 0;
8213 static void perf_swevent_stop(struct perf_event *event, int flags)
8215 event->hw.state = PERF_HES_STOPPED;
8218 /* Deref the hlist from the update side */
8219 static inline struct swevent_hlist *
8220 swevent_hlist_deref(struct swevent_htable *swhash)
8222 return rcu_dereference_protected(swhash->swevent_hlist,
8223 lockdep_is_held(&swhash->hlist_mutex));
8226 static void swevent_hlist_release(struct swevent_htable *swhash)
8228 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
8233 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
8234 kfree_rcu(hlist, rcu_head);
8237 static void swevent_hlist_put_cpu(int cpu)
8239 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8241 mutex_lock(&swhash->hlist_mutex);
8243 if (!--swhash->hlist_refcount)
8244 swevent_hlist_release(swhash);
8246 mutex_unlock(&swhash->hlist_mutex);
8249 static void swevent_hlist_put(void)
8253 for_each_possible_cpu(cpu)
8254 swevent_hlist_put_cpu(cpu);
8257 static int swevent_hlist_get_cpu(int cpu)
8259 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8262 mutex_lock(&swhash->hlist_mutex);
8263 if (!swevent_hlist_deref(swhash) &&
8264 cpumask_test_cpu(cpu, perf_online_mask)) {
8265 struct swevent_hlist *hlist;
8267 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
8272 rcu_assign_pointer(swhash->swevent_hlist, hlist);
8274 swhash->hlist_refcount++;
8276 mutex_unlock(&swhash->hlist_mutex);
8281 static int swevent_hlist_get(void)
8283 int err, cpu, failed_cpu;
8285 mutex_lock(&pmus_lock);
8286 for_each_possible_cpu(cpu) {
8287 err = swevent_hlist_get_cpu(cpu);
8293 mutex_unlock(&pmus_lock);
8296 for_each_possible_cpu(cpu) {
8297 if (cpu == failed_cpu)
8299 swevent_hlist_put_cpu(cpu);
8301 mutex_unlock(&pmus_lock);
8305 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
8307 static void sw_perf_event_destroy(struct perf_event *event)
8309 u64 event_id = event->attr.config;
8311 WARN_ON(event->parent);
8313 static_key_slow_dec(&perf_swevent_enabled[event_id]);
8314 swevent_hlist_put();
8317 static int perf_swevent_init(struct perf_event *event)
8319 u64 event_id = event->attr.config;
8321 if (event->attr.type != PERF_TYPE_SOFTWARE)
8325 * no branch sampling for software events
8327 if (has_branch_stack(event))
8331 case PERF_COUNT_SW_CPU_CLOCK:
8332 case PERF_COUNT_SW_TASK_CLOCK:
8339 if (event_id >= PERF_COUNT_SW_MAX)
8342 if (!event->parent) {
8345 err = swevent_hlist_get();
8349 static_key_slow_inc(&perf_swevent_enabled[event_id]);
8350 event->destroy = sw_perf_event_destroy;
8356 static struct pmu perf_swevent = {
8357 .task_ctx_nr = perf_sw_context,
8359 .capabilities = PERF_PMU_CAP_NO_NMI,
8361 .event_init = perf_swevent_init,
8362 .add = perf_swevent_add,
8363 .del = perf_swevent_del,
8364 .start = perf_swevent_start,
8365 .stop = perf_swevent_stop,
8366 .read = perf_swevent_read,
8369 #ifdef CONFIG_EVENT_TRACING
8371 static int perf_tp_filter_match(struct perf_event *event,
8372 struct perf_sample_data *data)
8374 void *record = data->raw->frag.data;
8376 /* only top level events have filters set */
8378 event = event->parent;
8380 if (likely(!event->filter) || filter_match_preds(event->filter, record))
8385 static int perf_tp_event_match(struct perf_event *event,
8386 struct perf_sample_data *data,
8387 struct pt_regs *regs)
8389 if (event->hw.state & PERF_HES_STOPPED)
8392 * All tracepoints are from kernel-space.
8394 if (event->attr.exclude_kernel)
8397 if (!perf_tp_filter_match(event, data))
8403 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8404 struct trace_event_call *call, u64 count,
8405 struct pt_regs *regs, struct hlist_head *head,
8406 struct task_struct *task)
8408 if (bpf_prog_array_valid(call)) {
8409 *(struct pt_regs **)raw_data = regs;
8410 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
8411 perf_swevent_put_recursion_context(rctx);
8415 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8418 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8420 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8421 struct pt_regs *regs, struct hlist_head *head, int rctx,
8422 struct task_struct *task)
8424 struct perf_sample_data data;
8425 struct perf_event *event;
8427 struct perf_raw_record raw = {
8434 perf_sample_data_init(&data, 0, 0);
8437 perf_trace_buf_update(record, event_type);
8439 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8440 if (perf_tp_event_match(event, &data, regs))
8441 perf_swevent_event(event, count, &data, regs);
8445 * If we got specified a target task, also iterate its context and
8446 * deliver this event there too.
8448 if (task && task != current) {
8449 struct perf_event_context *ctx;
8450 struct trace_entry *entry = record;
8453 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8457 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8458 if (event->cpu != smp_processor_id())
8460 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8462 if (event->attr.config != entry->type)
8464 if (perf_tp_event_match(event, &data, regs))
8465 perf_swevent_event(event, count, &data, regs);
8471 perf_swevent_put_recursion_context(rctx);
8473 EXPORT_SYMBOL_GPL(perf_tp_event);
8475 static void tp_perf_event_destroy(struct perf_event *event)
8477 perf_trace_destroy(event);
8480 static int perf_tp_event_init(struct perf_event *event)
8484 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8488 * no branch sampling for tracepoint events
8490 if (has_branch_stack(event))
8493 err = perf_trace_init(event);
8497 event->destroy = tp_perf_event_destroy;
8502 static struct pmu perf_tracepoint = {
8503 .task_ctx_nr = perf_sw_context,
8505 .event_init = perf_tp_event_init,
8506 .add = perf_trace_add,
8507 .del = perf_trace_del,
8508 .start = perf_swevent_start,
8509 .stop = perf_swevent_stop,
8510 .read = perf_swevent_read,
8513 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
8515 * Flags in config, used by dynamic PMU kprobe and uprobe
8516 * The flags should match following PMU_FORMAT_ATTR().
8518 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
8519 * if not set, create kprobe/uprobe
8521 enum perf_probe_config {
8522 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
8525 PMU_FORMAT_ATTR(retprobe, "config:0");
8527 static struct attribute *probe_attrs[] = {
8528 &format_attr_retprobe.attr,
8532 static struct attribute_group probe_format_group = {
8534 .attrs = probe_attrs,
8537 static const struct attribute_group *probe_attr_groups[] = {
8538 &probe_format_group,
8543 #ifdef CONFIG_KPROBE_EVENTS
8544 static int perf_kprobe_event_init(struct perf_event *event);
8545 static struct pmu perf_kprobe = {
8546 .task_ctx_nr = perf_sw_context,
8547 .event_init = perf_kprobe_event_init,
8548 .add = perf_trace_add,
8549 .del = perf_trace_del,
8550 .start = perf_swevent_start,
8551 .stop = perf_swevent_stop,
8552 .read = perf_swevent_read,
8553 .attr_groups = probe_attr_groups,
8556 static int perf_kprobe_event_init(struct perf_event *event)
8561 if (event->attr.type != perf_kprobe.type)
8564 if (!capable(CAP_SYS_ADMIN))
8568 * no branch sampling for probe events
8570 if (has_branch_stack(event))
8573 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8574 err = perf_kprobe_init(event, is_retprobe);
8578 event->destroy = perf_kprobe_destroy;
8582 #endif /* CONFIG_KPROBE_EVENTS */
8584 #ifdef CONFIG_UPROBE_EVENTS
8585 static int perf_uprobe_event_init(struct perf_event *event);
8586 static struct pmu perf_uprobe = {
8587 .task_ctx_nr = perf_sw_context,
8588 .event_init = perf_uprobe_event_init,
8589 .add = perf_trace_add,
8590 .del = perf_trace_del,
8591 .start = perf_swevent_start,
8592 .stop = perf_swevent_stop,
8593 .read = perf_swevent_read,
8594 .attr_groups = probe_attr_groups,
8597 static int perf_uprobe_event_init(struct perf_event *event)
8602 if (event->attr.type != perf_uprobe.type)
8605 if (!capable(CAP_SYS_ADMIN))
8609 * no branch sampling for probe events
8611 if (has_branch_stack(event))
8614 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8615 err = perf_uprobe_init(event, is_retprobe);
8619 event->destroy = perf_uprobe_destroy;
8623 #endif /* CONFIG_UPROBE_EVENTS */
8625 static inline void perf_tp_register(void)
8627 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8628 #ifdef CONFIG_KPROBE_EVENTS
8629 perf_pmu_register(&perf_kprobe, "kprobe", -1);
8631 #ifdef CONFIG_UPROBE_EVENTS
8632 perf_pmu_register(&perf_uprobe, "uprobe", -1);
8636 static void perf_event_free_filter(struct perf_event *event)
8638 ftrace_profile_free_filter(event);
8641 #ifdef CONFIG_BPF_SYSCALL
8642 static void bpf_overflow_handler(struct perf_event *event,
8643 struct perf_sample_data *data,
8644 struct pt_regs *regs)
8646 struct bpf_perf_event_data_kern ctx = {
8652 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
8654 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8657 ret = BPF_PROG_RUN(event->prog, &ctx);
8660 __this_cpu_dec(bpf_prog_active);
8665 event->orig_overflow_handler(event, data, regs);
8668 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8670 struct bpf_prog *prog;
8672 if (event->overflow_handler_context)
8673 /* hw breakpoint or kernel counter */
8679 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8681 return PTR_ERR(prog);
8684 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8685 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8689 static void perf_event_free_bpf_handler(struct perf_event *event)
8691 struct bpf_prog *prog = event->prog;
8696 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8701 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8705 static void perf_event_free_bpf_handler(struct perf_event *event)
8711 * returns true if the event is a tracepoint, or a kprobe/upprobe created
8712 * with perf_event_open()
8714 static inline bool perf_event_is_tracing(struct perf_event *event)
8716 if (event->pmu == &perf_tracepoint)
8718 #ifdef CONFIG_KPROBE_EVENTS
8719 if (event->pmu == &perf_kprobe)
8722 #ifdef CONFIG_UPROBE_EVENTS
8723 if (event->pmu == &perf_uprobe)
8729 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8731 bool is_kprobe, is_tracepoint, is_syscall_tp;
8732 struct bpf_prog *prog;
8735 if (!perf_event_is_tracing(event))
8736 return perf_event_set_bpf_handler(event, prog_fd);
8738 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8739 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8740 is_syscall_tp = is_syscall_trace_event(event->tp_event);
8741 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
8742 /* bpf programs can only be attached to u/kprobe or tracepoint */
8745 prog = bpf_prog_get(prog_fd);
8747 return PTR_ERR(prog);
8749 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8750 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
8751 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8752 /* valid fd, but invalid bpf program type */
8757 /* Kprobe override only works for kprobes, not uprobes. */
8758 if (prog->kprobe_override &&
8759 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
8764 if (is_tracepoint || is_syscall_tp) {
8765 int off = trace_event_get_offsets(event->tp_event);
8767 if (prog->aux->max_ctx_offset > off) {
8773 ret = perf_event_attach_bpf_prog(event, prog);
8779 static void perf_event_free_bpf_prog(struct perf_event *event)
8781 if (!perf_event_is_tracing(event)) {
8782 perf_event_free_bpf_handler(event);
8785 perf_event_detach_bpf_prog(event);
8790 static inline void perf_tp_register(void)
8794 static void perf_event_free_filter(struct perf_event *event)
8798 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8803 static void perf_event_free_bpf_prog(struct perf_event *event)
8806 #endif /* CONFIG_EVENT_TRACING */
8808 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8809 void perf_bp_event(struct perf_event *bp, void *data)
8811 struct perf_sample_data sample;
8812 struct pt_regs *regs = data;
8814 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8816 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8817 perf_swevent_event(bp, 1, &sample, regs);
8822 * Allocate a new address filter
8824 static struct perf_addr_filter *
8825 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8827 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8828 struct perf_addr_filter *filter;
8830 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8834 INIT_LIST_HEAD(&filter->entry);
8835 list_add_tail(&filter->entry, filters);
8840 static void free_filters_list(struct list_head *filters)
8842 struct perf_addr_filter *filter, *iter;
8844 list_for_each_entry_safe(filter, iter, filters, entry) {
8845 path_put(&filter->path);
8846 list_del(&filter->entry);
8852 * Free existing address filters and optionally install new ones
8854 static void perf_addr_filters_splice(struct perf_event *event,
8855 struct list_head *head)
8857 unsigned long flags;
8860 if (!has_addr_filter(event))
8863 /* don't bother with children, they don't have their own filters */
8867 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8869 list_splice_init(&event->addr_filters.list, &list);
8871 list_splice(head, &event->addr_filters.list);
8873 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8875 free_filters_list(&list);
8879 * Scan through mm's vmas and see if one of them matches the
8880 * @filter; if so, adjust filter's address range.
8881 * Called with mm::mmap_sem down for reading.
8883 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
8884 struct mm_struct *mm,
8885 struct perf_addr_filter_range *fr)
8887 struct vm_area_struct *vma;
8889 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8893 if (perf_addr_filter_vma_adjust(filter, vma, fr))
8899 * Update event's address range filters based on the
8900 * task's existing mappings, if any.
8902 static void perf_event_addr_filters_apply(struct perf_event *event)
8904 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8905 struct task_struct *task = READ_ONCE(event->ctx->task);
8906 struct perf_addr_filter *filter;
8907 struct mm_struct *mm = NULL;
8908 unsigned int count = 0;
8909 unsigned long flags;
8912 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8913 * will stop on the parent's child_mutex that our caller is also holding
8915 if (task == TASK_TOMBSTONE)
8918 if (ifh->nr_file_filters) {
8919 mm = get_task_mm(event->ctx->task);
8923 down_read(&mm->mmap_sem);
8926 raw_spin_lock_irqsave(&ifh->lock, flags);
8927 list_for_each_entry(filter, &ifh->list, entry) {
8928 if (filter->path.dentry) {
8930 * Adjust base offset if the filter is associated to a
8931 * binary that needs to be mapped:
8933 event->addr_filter_ranges[count].start = 0;
8934 event->addr_filter_ranges[count].size = 0;
8936 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
8938 event->addr_filter_ranges[count].start = filter->offset;
8939 event->addr_filter_ranges[count].size = filter->size;
8945 event->addr_filters_gen++;
8946 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8948 if (ifh->nr_file_filters) {
8949 up_read(&mm->mmap_sem);
8955 perf_event_stop(event, 1);
8959 * Address range filtering: limiting the data to certain
8960 * instruction address ranges. Filters are ioctl()ed to us from
8961 * userspace as ascii strings.
8963 * Filter string format:
8966 * where ACTION is one of the
8967 * * "filter": limit the trace to this region
8968 * * "start": start tracing from this address
8969 * * "stop": stop tracing at this address/region;
8971 * * for kernel addresses: <start address>[/<size>]
8972 * * for object files: <start address>[/<size>]@</path/to/object/file>
8974 * if <size> is not specified or is zero, the range is treated as a single
8975 * address; not valid for ACTION=="filter".
8989 IF_STATE_ACTION = 0,
8994 static const match_table_t if_tokens = {
8995 { IF_ACT_FILTER, "filter" },
8996 { IF_ACT_START, "start" },
8997 { IF_ACT_STOP, "stop" },
8998 { IF_SRC_FILE, "%u/%u@%s" },
8999 { IF_SRC_KERNEL, "%u/%u" },
9000 { IF_SRC_FILEADDR, "%u@%s" },
9001 { IF_SRC_KERNELADDR, "%u" },
9002 { IF_ACT_NONE, NULL },
9006 * Address filter string parser
9009 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
9010 struct list_head *filters)
9012 struct perf_addr_filter *filter = NULL;
9013 char *start, *orig, *filename = NULL;
9014 substring_t args[MAX_OPT_ARGS];
9015 int state = IF_STATE_ACTION, token;
9016 unsigned int kernel = 0;
9019 orig = fstr = kstrdup(fstr, GFP_KERNEL);
9023 while ((start = strsep(&fstr, " ,\n")) != NULL) {
9024 static const enum perf_addr_filter_action_t actions[] = {
9025 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
9026 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
9027 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
9034 /* filter definition begins */
9035 if (state == IF_STATE_ACTION) {
9036 filter = perf_addr_filter_new(event, filters);
9041 token = match_token(start, if_tokens, args);
9046 if (state != IF_STATE_ACTION)
9049 filter->action = actions[token];
9050 state = IF_STATE_SOURCE;
9053 case IF_SRC_KERNELADDR:
9057 case IF_SRC_FILEADDR:
9059 if (state != IF_STATE_SOURCE)
9063 ret = kstrtoul(args[0].from, 0, &filter->offset);
9067 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
9069 ret = kstrtoul(args[1].from, 0, &filter->size);
9074 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9075 int fpos = token == IF_SRC_FILE ? 2 : 1;
9078 filename = match_strdup(&args[fpos]);
9085 state = IF_STATE_END;
9093 * Filter definition is fully parsed, validate and install it.
9094 * Make sure that it doesn't contradict itself or the event's
9097 if (state == IF_STATE_END) {
9099 if (kernel && event->attr.exclude_kernel)
9103 * ACTION "filter" must have a non-zero length region
9106 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9115 * For now, we only support file-based filters
9116 * in per-task events; doing so for CPU-wide
9117 * events requires additional context switching
9118 * trickery, since same object code will be
9119 * mapped at different virtual addresses in
9120 * different processes.
9123 if (!event->ctx->task)
9126 /* look up the path and grab its inode */
9127 ret = kern_path(filename, LOOKUP_FOLLOW,
9133 if (!filter->path.dentry ||
9134 !S_ISREG(d_inode(filter->path.dentry)
9138 event->addr_filters.nr_file_filters++;
9141 /* ready to consume more filters */
9142 state = IF_STATE_ACTION;
9147 if (state != IF_STATE_ACTION)
9157 free_filters_list(filters);
9164 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
9170 * Since this is called in perf_ioctl() path, we're already holding
9173 lockdep_assert_held(&event->ctx->mutex);
9175 if (WARN_ON_ONCE(event->parent))
9178 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
9180 goto fail_clear_files;
9182 ret = event->pmu->addr_filters_validate(&filters);
9184 goto fail_free_filters;
9186 /* remove existing filters, if any */
9187 perf_addr_filters_splice(event, &filters);
9189 /* install new filters */
9190 perf_event_for_each_child(event, perf_event_addr_filters_apply);
9195 free_filters_list(&filters);
9198 event->addr_filters.nr_file_filters = 0;
9203 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
9208 filter_str = strndup_user(arg, PAGE_SIZE);
9209 if (IS_ERR(filter_str))
9210 return PTR_ERR(filter_str);
9212 #ifdef CONFIG_EVENT_TRACING
9213 if (perf_event_is_tracing(event)) {
9214 struct perf_event_context *ctx = event->ctx;
9217 * Beware, here be dragons!!
9219 * the tracepoint muck will deadlock against ctx->mutex, but
9220 * the tracepoint stuff does not actually need it. So
9221 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
9222 * already have a reference on ctx.
9224 * This can result in event getting moved to a different ctx,
9225 * but that does not affect the tracepoint state.
9227 mutex_unlock(&ctx->mutex);
9228 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
9229 mutex_lock(&ctx->mutex);
9232 if (has_addr_filter(event))
9233 ret = perf_event_set_addr_filter(event, filter_str);
9240 * hrtimer based swevent callback
9243 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
9245 enum hrtimer_restart ret = HRTIMER_RESTART;
9246 struct perf_sample_data data;
9247 struct pt_regs *regs;
9248 struct perf_event *event;
9251 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
9253 if (event->state != PERF_EVENT_STATE_ACTIVE)
9254 return HRTIMER_NORESTART;
9256 event->pmu->read(event);
9258 perf_sample_data_init(&data, 0, event->hw.last_period);
9259 regs = get_irq_regs();
9261 if (regs && !perf_exclude_event(event, regs)) {
9262 if (!(event->attr.exclude_idle && is_idle_task(current)))
9263 if (__perf_event_overflow(event, 1, &data, regs))
9264 ret = HRTIMER_NORESTART;
9267 period = max_t(u64, 10000, event->hw.sample_period);
9268 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
9273 static void perf_swevent_start_hrtimer(struct perf_event *event)
9275 struct hw_perf_event *hwc = &event->hw;
9278 if (!is_sampling_event(event))
9281 period = local64_read(&hwc->period_left);
9286 local64_set(&hwc->period_left, 0);
9288 period = max_t(u64, 10000, hwc->sample_period);
9290 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
9291 HRTIMER_MODE_REL_PINNED);
9294 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
9296 struct hw_perf_event *hwc = &event->hw;
9298 if (is_sampling_event(event)) {
9299 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
9300 local64_set(&hwc->period_left, ktime_to_ns(remaining));
9302 hrtimer_cancel(&hwc->hrtimer);
9306 static void perf_swevent_init_hrtimer(struct perf_event *event)
9308 struct hw_perf_event *hwc = &event->hw;
9310 if (!is_sampling_event(event))
9313 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
9314 hwc->hrtimer.function = perf_swevent_hrtimer;
9317 * Since hrtimers have a fixed rate, we can do a static freq->period
9318 * mapping and avoid the whole period adjust feedback stuff.
9320 if (event->attr.freq) {
9321 long freq = event->attr.sample_freq;
9323 event->attr.sample_period = NSEC_PER_SEC / freq;
9324 hwc->sample_period = event->attr.sample_period;
9325 local64_set(&hwc->period_left, hwc->sample_period);
9326 hwc->last_period = hwc->sample_period;
9327 event->attr.freq = 0;
9332 * Software event: cpu wall time clock
9335 static void cpu_clock_event_update(struct perf_event *event)
9340 now = local_clock();
9341 prev = local64_xchg(&event->hw.prev_count, now);
9342 local64_add(now - prev, &event->count);
9345 static void cpu_clock_event_start(struct perf_event *event, int flags)
9347 local64_set(&event->hw.prev_count, local_clock());
9348 perf_swevent_start_hrtimer(event);
9351 static void cpu_clock_event_stop(struct perf_event *event, int flags)
9353 perf_swevent_cancel_hrtimer(event);
9354 cpu_clock_event_update(event);
9357 static int cpu_clock_event_add(struct perf_event *event, int flags)
9359 if (flags & PERF_EF_START)
9360 cpu_clock_event_start(event, flags);
9361 perf_event_update_userpage(event);
9366 static void cpu_clock_event_del(struct perf_event *event, int flags)
9368 cpu_clock_event_stop(event, flags);
9371 static void cpu_clock_event_read(struct perf_event *event)
9373 cpu_clock_event_update(event);
9376 static int cpu_clock_event_init(struct perf_event *event)
9378 if (event->attr.type != PERF_TYPE_SOFTWARE)
9381 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
9385 * no branch sampling for software events
9387 if (has_branch_stack(event))
9390 perf_swevent_init_hrtimer(event);
9395 static struct pmu perf_cpu_clock = {
9396 .task_ctx_nr = perf_sw_context,
9398 .capabilities = PERF_PMU_CAP_NO_NMI,
9400 .event_init = cpu_clock_event_init,
9401 .add = cpu_clock_event_add,
9402 .del = cpu_clock_event_del,
9403 .start = cpu_clock_event_start,
9404 .stop = cpu_clock_event_stop,
9405 .read = cpu_clock_event_read,
9409 * Software event: task time clock
9412 static void task_clock_event_update(struct perf_event *event, u64 now)
9417 prev = local64_xchg(&event->hw.prev_count, now);
9419 local64_add(delta, &event->count);
9422 static void task_clock_event_start(struct perf_event *event, int flags)
9424 local64_set(&event->hw.prev_count, event->ctx->time);
9425 perf_swevent_start_hrtimer(event);
9428 static void task_clock_event_stop(struct perf_event *event, int flags)
9430 perf_swevent_cancel_hrtimer(event);
9431 task_clock_event_update(event, event->ctx->time);
9434 static int task_clock_event_add(struct perf_event *event, int flags)
9436 if (flags & PERF_EF_START)
9437 task_clock_event_start(event, flags);
9438 perf_event_update_userpage(event);
9443 static void task_clock_event_del(struct perf_event *event, int flags)
9445 task_clock_event_stop(event, PERF_EF_UPDATE);
9448 static void task_clock_event_read(struct perf_event *event)
9450 u64 now = perf_clock();
9451 u64 delta = now - event->ctx->timestamp;
9452 u64 time = event->ctx->time + delta;
9454 task_clock_event_update(event, time);
9457 static int task_clock_event_init(struct perf_event *event)
9459 if (event->attr.type != PERF_TYPE_SOFTWARE)
9462 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
9466 * no branch sampling for software events
9468 if (has_branch_stack(event))
9471 perf_swevent_init_hrtimer(event);
9476 static struct pmu perf_task_clock = {
9477 .task_ctx_nr = perf_sw_context,
9479 .capabilities = PERF_PMU_CAP_NO_NMI,
9481 .event_init = task_clock_event_init,
9482 .add = task_clock_event_add,
9483 .del = task_clock_event_del,
9484 .start = task_clock_event_start,
9485 .stop = task_clock_event_stop,
9486 .read = task_clock_event_read,
9489 static void perf_pmu_nop_void(struct pmu *pmu)
9493 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
9497 static int perf_pmu_nop_int(struct pmu *pmu)
9502 static int perf_event_nop_int(struct perf_event *event, u64 value)
9507 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
9509 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
9511 __this_cpu_write(nop_txn_flags, flags);
9513 if (flags & ~PERF_PMU_TXN_ADD)
9516 perf_pmu_disable(pmu);
9519 static int perf_pmu_commit_txn(struct pmu *pmu)
9521 unsigned int flags = __this_cpu_read(nop_txn_flags);
9523 __this_cpu_write(nop_txn_flags, 0);
9525 if (flags & ~PERF_PMU_TXN_ADD)
9528 perf_pmu_enable(pmu);
9532 static void perf_pmu_cancel_txn(struct pmu *pmu)
9534 unsigned int flags = __this_cpu_read(nop_txn_flags);
9536 __this_cpu_write(nop_txn_flags, 0);
9538 if (flags & ~PERF_PMU_TXN_ADD)
9541 perf_pmu_enable(pmu);
9544 static int perf_event_idx_default(struct perf_event *event)
9550 * Ensures all contexts with the same task_ctx_nr have the same
9551 * pmu_cpu_context too.
9553 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
9560 list_for_each_entry(pmu, &pmus, entry) {
9561 if (pmu->task_ctx_nr == ctxn)
9562 return pmu->pmu_cpu_context;
9568 static void free_pmu_context(struct pmu *pmu)
9571 * Static contexts such as perf_sw_context have a global lifetime
9572 * and may be shared between different PMUs. Avoid freeing them
9573 * when a single PMU is going away.
9575 if (pmu->task_ctx_nr > perf_invalid_context)
9578 free_percpu(pmu->pmu_cpu_context);
9582 * Let userspace know that this PMU supports address range filtering:
9584 static ssize_t nr_addr_filters_show(struct device *dev,
9585 struct device_attribute *attr,
9588 struct pmu *pmu = dev_get_drvdata(dev);
9590 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
9592 DEVICE_ATTR_RO(nr_addr_filters);
9594 static struct idr pmu_idr;
9597 type_show(struct device *dev, struct device_attribute *attr, char *page)
9599 struct pmu *pmu = dev_get_drvdata(dev);
9601 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
9603 static DEVICE_ATTR_RO(type);
9606 perf_event_mux_interval_ms_show(struct device *dev,
9607 struct device_attribute *attr,
9610 struct pmu *pmu = dev_get_drvdata(dev);
9612 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9615 static DEFINE_MUTEX(mux_interval_mutex);
9618 perf_event_mux_interval_ms_store(struct device *dev,
9619 struct device_attribute *attr,
9620 const char *buf, size_t count)
9622 struct pmu *pmu = dev_get_drvdata(dev);
9623 int timer, cpu, ret;
9625 ret = kstrtoint(buf, 0, &timer);
9632 /* same value, noting to do */
9633 if (timer == pmu->hrtimer_interval_ms)
9636 mutex_lock(&mux_interval_mutex);
9637 pmu->hrtimer_interval_ms = timer;
9639 /* update all cpuctx for this PMU */
9641 for_each_online_cpu(cpu) {
9642 struct perf_cpu_context *cpuctx;
9643 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9644 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9646 cpu_function_call(cpu,
9647 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
9650 mutex_unlock(&mux_interval_mutex);
9654 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9656 static struct attribute *pmu_dev_attrs[] = {
9657 &dev_attr_type.attr,
9658 &dev_attr_perf_event_mux_interval_ms.attr,
9661 ATTRIBUTE_GROUPS(pmu_dev);
9663 static int pmu_bus_running;
9664 static struct bus_type pmu_bus = {
9665 .name = "event_source",
9666 .dev_groups = pmu_dev_groups,
9669 static void pmu_dev_release(struct device *dev)
9674 static int pmu_dev_alloc(struct pmu *pmu)
9678 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9682 pmu->dev->groups = pmu->attr_groups;
9683 device_initialize(pmu->dev);
9684 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9688 dev_set_drvdata(pmu->dev, pmu);
9689 pmu->dev->bus = &pmu_bus;
9690 pmu->dev->release = pmu_dev_release;
9691 ret = device_add(pmu->dev);
9695 /* For PMUs with address filters, throw in an extra attribute: */
9696 if (pmu->nr_addr_filters)
9697 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9706 device_del(pmu->dev);
9709 put_device(pmu->dev);
9713 static struct lock_class_key cpuctx_mutex;
9714 static struct lock_class_key cpuctx_lock;
9716 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9720 mutex_lock(&pmus_lock);
9722 pmu->pmu_disable_count = alloc_percpu(int);
9723 if (!pmu->pmu_disable_count)
9732 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9740 if (pmu_bus_running) {
9741 ret = pmu_dev_alloc(pmu);
9747 if (pmu->task_ctx_nr == perf_hw_context) {
9748 static int hw_context_taken = 0;
9751 * Other than systems with heterogeneous CPUs, it never makes
9752 * sense for two PMUs to share perf_hw_context. PMUs which are
9753 * uncore must use perf_invalid_context.
9755 if (WARN_ON_ONCE(hw_context_taken &&
9756 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9757 pmu->task_ctx_nr = perf_invalid_context;
9759 hw_context_taken = 1;
9762 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9763 if (pmu->pmu_cpu_context)
9764 goto got_cpu_context;
9767 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9768 if (!pmu->pmu_cpu_context)
9771 for_each_possible_cpu(cpu) {
9772 struct perf_cpu_context *cpuctx;
9774 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9775 __perf_event_init_context(&cpuctx->ctx);
9776 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9777 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9778 cpuctx->ctx.pmu = pmu;
9779 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9781 __perf_mux_hrtimer_init(cpuctx, cpu);
9785 if (!pmu->start_txn) {
9786 if (pmu->pmu_enable) {
9788 * If we have pmu_enable/pmu_disable calls, install
9789 * transaction stubs that use that to try and batch
9790 * hardware accesses.
9792 pmu->start_txn = perf_pmu_start_txn;
9793 pmu->commit_txn = perf_pmu_commit_txn;
9794 pmu->cancel_txn = perf_pmu_cancel_txn;
9796 pmu->start_txn = perf_pmu_nop_txn;
9797 pmu->commit_txn = perf_pmu_nop_int;
9798 pmu->cancel_txn = perf_pmu_nop_void;
9802 if (!pmu->pmu_enable) {
9803 pmu->pmu_enable = perf_pmu_nop_void;
9804 pmu->pmu_disable = perf_pmu_nop_void;
9807 if (!pmu->check_period)
9808 pmu->check_period = perf_event_nop_int;
9810 if (!pmu->event_idx)
9811 pmu->event_idx = perf_event_idx_default;
9813 list_add_rcu(&pmu->entry, &pmus);
9814 atomic_set(&pmu->exclusive_cnt, 0);
9817 mutex_unlock(&pmus_lock);
9822 device_del(pmu->dev);
9823 put_device(pmu->dev);
9826 if (pmu->type >= PERF_TYPE_MAX)
9827 idr_remove(&pmu_idr, pmu->type);
9830 free_percpu(pmu->pmu_disable_count);
9833 EXPORT_SYMBOL_GPL(perf_pmu_register);
9835 void perf_pmu_unregister(struct pmu *pmu)
9837 mutex_lock(&pmus_lock);
9838 list_del_rcu(&pmu->entry);
9841 * We dereference the pmu list under both SRCU and regular RCU, so
9842 * synchronize against both of those.
9844 synchronize_srcu(&pmus_srcu);
9847 free_percpu(pmu->pmu_disable_count);
9848 if (pmu->type >= PERF_TYPE_MAX)
9849 idr_remove(&pmu_idr, pmu->type);
9850 if (pmu_bus_running) {
9851 if (pmu->nr_addr_filters)
9852 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9853 device_del(pmu->dev);
9854 put_device(pmu->dev);
9856 free_pmu_context(pmu);
9857 mutex_unlock(&pmus_lock);
9859 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9861 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9863 struct perf_event_context *ctx = NULL;
9866 if (!try_module_get(pmu->module))
9870 * A number of pmu->event_init() methods iterate the sibling_list to,
9871 * for example, validate if the group fits on the PMU. Therefore,
9872 * if this is a sibling event, acquire the ctx->mutex to protect
9875 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
9877 * This ctx->mutex can nest when we're called through
9878 * inheritance. See the perf_event_ctx_lock_nested() comment.
9880 ctx = perf_event_ctx_lock_nested(event->group_leader,
9881 SINGLE_DEPTH_NESTING);
9886 ret = pmu->event_init(event);
9889 perf_event_ctx_unlock(event->group_leader, ctx);
9892 module_put(pmu->module);
9897 static struct pmu *perf_init_event(struct perf_event *event)
9903 idx = srcu_read_lock(&pmus_srcu);
9905 /* Try parent's PMU first: */
9906 if (event->parent && event->parent->pmu) {
9907 pmu = event->parent->pmu;
9908 ret = perf_try_init_event(pmu, event);
9914 pmu = idr_find(&pmu_idr, event->attr.type);
9917 ret = perf_try_init_event(pmu, event);
9923 list_for_each_entry_rcu(pmu, &pmus, entry) {
9924 ret = perf_try_init_event(pmu, event);
9928 if (ret != -ENOENT) {
9933 pmu = ERR_PTR(-ENOENT);
9935 srcu_read_unlock(&pmus_srcu, idx);
9940 static void attach_sb_event(struct perf_event *event)
9942 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9944 raw_spin_lock(&pel->lock);
9945 list_add_rcu(&event->sb_list, &pel->list);
9946 raw_spin_unlock(&pel->lock);
9950 * We keep a list of all !task (and therefore per-cpu) events
9951 * that need to receive side-band records.
9953 * This avoids having to scan all the various PMU per-cpu contexts
9956 static void account_pmu_sb_event(struct perf_event *event)
9958 if (is_sb_event(event))
9959 attach_sb_event(event);
9962 static void account_event_cpu(struct perf_event *event, int cpu)
9967 if (is_cgroup_event(event))
9968 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9971 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9972 static void account_freq_event_nohz(void)
9974 #ifdef CONFIG_NO_HZ_FULL
9975 /* Lock so we don't race with concurrent unaccount */
9976 spin_lock(&nr_freq_lock);
9977 if (atomic_inc_return(&nr_freq_events) == 1)
9978 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9979 spin_unlock(&nr_freq_lock);
9983 static void account_freq_event(void)
9985 if (tick_nohz_full_enabled())
9986 account_freq_event_nohz();
9988 atomic_inc(&nr_freq_events);
9992 static void account_event(struct perf_event *event)
9999 if (event->attach_state & PERF_ATTACH_TASK)
10001 if (event->attr.mmap || event->attr.mmap_data)
10002 atomic_inc(&nr_mmap_events);
10003 if (event->attr.comm)
10004 atomic_inc(&nr_comm_events);
10005 if (event->attr.namespaces)
10006 atomic_inc(&nr_namespaces_events);
10007 if (event->attr.task)
10008 atomic_inc(&nr_task_events);
10009 if (event->attr.freq)
10010 account_freq_event();
10011 if (event->attr.context_switch) {
10012 atomic_inc(&nr_switch_events);
10015 if (has_branch_stack(event))
10017 if (is_cgroup_event(event))
10022 * We need the mutex here because static_branch_enable()
10023 * must complete *before* the perf_sched_count increment
10026 if (atomic_inc_not_zero(&perf_sched_count))
10029 mutex_lock(&perf_sched_mutex);
10030 if (!atomic_read(&perf_sched_count)) {
10031 static_branch_enable(&perf_sched_events);
10033 * Guarantee that all CPUs observe they key change and
10034 * call the perf scheduling hooks before proceeding to
10035 * install events that need them.
10037 synchronize_sched();
10040 * Now that we have waited for the sync_sched(), allow further
10041 * increments to by-pass the mutex.
10043 atomic_inc(&perf_sched_count);
10044 mutex_unlock(&perf_sched_mutex);
10048 account_event_cpu(event, event->cpu);
10050 account_pmu_sb_event(event);
10054 * Allocate and initialize an event structure
10056 static struct perf_event *
10057 perf_event_alloc(struct perf_event_attr *attr, int cpu,
10058 struct task_struct *task,
10059 struct perf_event *group_leader,
10060 struct perf_event *parent_event,
10061 perf_overflow_handler_t overflow_handler,
10062 void *context, int cgroup_fd)
10065 struct perf_event *event;
10066 struct hw_perf_event *hwc;
10067 long err = -EINVAL;
10069 if ((unsigned)cpu >= nr_cpu_ids) {
10070 if (!task || cpu != -1)
10071 return ERR_PTR(-EINVAL);
10074 event = kzalloc(sizeof(*event), GFP_KERNEL);
10076 return ERR_PTR(-ENOMEM);
10079 * Single events are their own group leaders, with an
10080 * empty sibling list:
10083 group_leader = event;
10085 mutex_init(&event->child_mutex);
10086 INIT_LIST_HEAD(&event->child_list);
10088 INIT_LIST_HEAD(&event->event_entry);
10089 INIT_LIST_HEAD(&event->sibling_list);
10090 INIT_LIST_HEAD(&event->active_list);
10091 init_event_group(event);
10092 INIT_LIST_HEAD(&event->rb_entry);
10093 INIT_LIST_HEAD(&event->active_entry);
10094 INIT_LIST_HEAD(&event->addr_filters.list);
10095 INIT_HLIST_NODE(&event->hlist_entry);
10098 init_waitqueue_head(&event->waitq);
10099 event->pending_disable = -1;
10100 init_irq_work(&event->pending, perf_pending_event);
10102 mutex_init(&event->mmap_mutex);
10103 raw_spin_lock_init(&event->addr_filters.lock);
10105 atomic_long_set(&event->refcount, 1);
10107 event->attr = *attr;
10108 event->group_leader = group_leader;
10112 event->parent = parent_event;
10114 event->ns = get_pid_ns(task_active_pid_ns(current));
10115 event->id = atomic64_inc_return(&perf_event_id);
10117 event->state = PERF_EVENT_STATE_INACTIVE;
10120 event->attach_state = PERF_ATTACH_TASK;
10122 * XXX pmu::event_init needs to know what task to account to
10123 * and we cannot use the ctx information because we need the
10124 * pmu before we get a ctx.
10126 get_task_struct(task);
10127 event->hw.target = task;
10130 event->clock = &local_clock;
10132 event->clock = parent_event->clock;
10134 if (!overflow_handler && parent_event) {
10135 overflow_handler = parent_event->overflow_handler;
10136 context = parent_event->overflow_handler_context;
10137 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
10138 if (overflow_handler == bpf_overflow_handler) {
10139 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
10141 if (IS_ERR(prog)) {
10142 err = PTR_ERR(prog);
10145 event->prog = prog;
10146 event->orig_overflow_handler =
10147 parent_event->orig_overflow_handler;
10152 if (overflow_handler) {
10153 event->overflow_handler = overflow_handler;
10154 event->overflow_handler_context = context;
10155 } else if (is_write_backward(event)){
10156 event->overflow_handler = perf_event_output_backward;
10157 event->overflow_handler_context = NULL;
10159 event->overflow_handler = perf_event_output_forward;
10160 event->overflow_handler_context = NULL;
10163 perf_event__state_init(event);
10168 hwc->sample_period = attr->sample_period;
10169 if (attr->freq && attr->sample_freq)
10170 hwc->sample_period = 1;
10171 hwc->last_period = hwc->sample_period;
10173 local64_set(&hwc->period_left, hwc->sample_period);
10176 * We currently do not support PERF_SAMPLE_READ on inherited events.
10177 * See perf_output_read().
10179 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
10182 if (!has_branch_stack(event))
10183 event->attr.branch_sample_type = 0;
10185 if (cgroup_fd != -1) {
10186 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
10191 pmu = perf_init_event(event);
10193 err = PTR_ERR(pmu);
10197 err = exclusive_event_init(event);
10201 if (has_addr_filter(event)) {
10202 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
10203 sizeof(struct perf_addr_filter_range),
10205 if (!event->addr_filter_ranges) {
10211 * Clone the parent's vma offsets: they are valid until exec()
10212 * even if the mm is not shared with the parent.
10214 if (event->parent) {
10215 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10217 raw_spin_lock_irq(&ifh->lock);
10218 memcpy(event->addr_filter_ranges,
10219 event->parent->addr_filter_ranges,
10220 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
10221 raw_spin_unlock_irq(&ifh->lock);
10224 /* force hw sync on the address filters */
10225 event->addr_filters_gen = 1;
10228 if (!event->parent) {
10229 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
10230 err = get_callchain_buffers(attr->sample_max_stack);
10232 goto err_addr_filters;
10236 err = security_perf_event_alloc(event);
10238 goto err_callchain_buffer;
10240 /* symmetric to unaccount_event() in _free_event() */
10241 account_event(event);
10245 err_callchain_buffer:
10246 if (!event->parent) {
10247 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
10248 put_callchain_buffers();
10251 kfree(event->addr_filter_ranges);
10254 exclusive_event_destroy(event);
10257 if (event->destroy)
10258 event->destroy(event);
10259 module_put(pmu->module);
10261 if (is_cgroup_event(event))
10262 perf_detach_cgroup(event);
10264 put_pid_ns(event->ns);
10265 if (event->hw.target)
10266 put_task_struct(event->hw.target);
10269 return ERR_PTR(err);
10272 static int perf_copy_attr(struct perf_event_attr __user *uattr,
10273 struct perf_event_attr *attr)
10278 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
10282 * zero the full structure, so that a short copy will be nice.
10284 memset(attr, 0, sizeof(*attr));
10286 ret = get_user(size, &uattr->size);
10290 if (size > PAGE_SIZE) /* silly large */
10293 if (!size) /* abi compat */
10294 size = PERF_ATTR_SIZE_VER0;
10296 if (size < PERF_ATTR_SIZE_VER0)
10300 * If we're handed a bigger struct than we know of,
10301 * ensure all the unknown bits are 0 - i.e. new
10302 * user-space does not rely on any kernel feature
10303 * extensions we dont know about yet.
10305 if (size > sizeof(*attr)) {
10306 unsigned char __user *addr;
10307 unsigned char __user *end;
10310 addr = (void __user *)uattr + sizeof(*attr);
10311 end = (void __user *)uattr + size;
10313 for (; addr < end; addr++) {
10314 ret = get_user(val, addr);
10320 size = sizeof(*attr);
10323 ret = copy_from_user(attr, uattr, size);
10329 if (attr->__reserved_1)
10332 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
10335 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
10338 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
10339 u64 mask = attr->branch_sample_type;
10341 /* only using defined bits */
10342 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
10345 /* at least one branch bit must be set */
10346 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
10349 /* propagate priv level, when not set for branch */
10350 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
10352 /* exclude_kernel checked on syscall entry */
10353 if (!attr->exclude_kernel)
10354 mask |= PERF_SAMPLE_BRANCH_KERNEL;
10356 if (!attr->exclude_user)
10357 mask |= PERF_SAMPLE_BRANCH_USER;
10359 if (!attr->exclude_hv)
10360 mask |= PERF_SAMPLE_BRANCH_HV;
10362 * adjust user setting (for HW filter setup)
10364 attr->branch_sample_type = mask;
10366 /* privileged levels capture (kernel, hv): check permissions */
10367 if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
10368 ret = perf_allow_kernel(attr);
10374 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
10375 ret = perf_reg_validate(attr->sample_regs_user);
10380 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
10381 if (!arch_perf_have_user_stack_dump())
10385 * We have __u32 type for the size, but so far
10386 * we can only use __u16 as maximum due to the
10387 * __u16 sample size limit.
10389 if (attr->sample_stack_user >= USHRT_MAX)
10391 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
10395 if (!attr->sample_max_stack)
10396 attr->sample_max_stack = sysctl_perf_event_max_stack;
10398 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
10399 ret = perf_reg_validate(attr->sample_regs_intr);
10404 put_user(sizeof(*attr), &uattr->size);
10410 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
10412 struct ring_buffer *rb = NULL;
10418 /* don't allow circular references */
10419 if (event == output_event)
10423 * Don't allow cross-cpu buffers
10425 if (output_event->cpu != event->cpu)
10429 * If its not a per-cpu rb, it must be the same task.
10431 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
10435 * Mixing clocks in the same buffer is trouble you don't need.
10437 if (output_event->clock != event->clock)
10441 * Either writing ring buffer from beginning or from end.
10442 * Mixing is not allowed.
10444 if (is_write_backward(output_event) != is_write_backward(event))
10448 * If both events generate aux data, they must be on the same PMU
10450 if (has_aux(event) && has_aux(output_event) &&
10451 event->pmu != output_event->pmu)
10455 mutex_lock(&event->mmap_mutex);
10456 /* Can't redirect output if we've got an active mmap() */
10457 if (atomic_read(&event->mmap_count))
10460 if (output_event) {
10461 /* get the rb we want to redirect to */
10462 rb = ring_buffer_get(output_event);
10467 ring_buffer_attach(event, rb);
10471 mutex_unlock(&event->mmap_mutex);
10477 static void mutex_lock_double(struct mutex *a, struct mutex *b)
10483 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
10486 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
10488 bool nmi_safe = false;
10491 case CLOCK_MONOTONIC:
10492 event->clock = &ktime_get_mono_fast_ns;
10496 case CLOCK_MONOTONIC_RAW:
10497 event->clock = &ktime_get_raw_fast_ns;
10501 case CLOCK_REALTIME:
10502 event->clock = &ktime_get_real_ns;
10505 case CLOCK_BOOTTIME:
10506 event->clock = &ktime_get_boot_ns;
10510 event->clock = &ktime_get_tai_ns;
10517 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
10524 * Variation on perf_event_ctx_lock_nested(), except we take two context
10527 static struct perf_event_context *
10528 __perf_event_ctx_lock_double(struct perf_event *group_leader,
10529 struct perf_event_context *ctx)
10531 struct perf_event_context *gctx;
10535 gctx = READ_ONCE(group_leader->ctx);
10536 if (!atomic_inc_not_zero(&gctx->refcount)) {
10542 mutex_lock_double(&gctx->mutex, &ctx->mutex);
10544 if (group_leader->ctx != gctx) {
10545 mutex_unlock(&ctx->mutex);
10546 mutex_unlock(&gctx->mutex);
10555 * sys_perf_event_open - open a performance event, associate it to a task/cpu
10557 * @attr_uptr: event_id type attributes for monitoring/sampling
10560 * @group_fd: group leader event fd
10562 SYSCALL_DEFINE5(perf_event_open,
10563 struct perf_event_attr __user *, attr_uptr,
10564 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
10566 struct perf_event *group_leader = NULL, *output_event = NULL;
10567 struct perf_event *event, *sibling;
10568 struct perf_event_attr attr;
10569 struct perf_event_context *ctx, *uninitialized_var(gctx);
10570 struct file *event_file = NULL;
10571 struct fd group = {NULL, 0};
10572 struct task_struct *task = NULL;
10575 int move_group = 0;
10577 int f_flags = O_RDWR;
10578 int cgroup_fd = -1;
10580 /* for future expandability... */
10581 if (flags & ~PERF_FLAG_ALL)
10584 /* Do we allow access to perf_event_open(2) ? */
10585 err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
10589 err = perf_copy_attr(attr_uptr, &attr);
10593 if (!attr.exclude_kernel) {
10594 err = perf_allow_kernel(&attr);
10599 if (attr.namespaces) {
10600 if (!capable(CAP_SYS_ADMIN))
10605 if (attr.sample_freq > sysctl_perf_event_sample_rate)
10608 if (attr.sample_period & (1ULL << 63))
10612 /* Only privileged users can get physical addresses */
10613 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
10614 err = perf_allow_kernel(&attr);
10620 * In cgroup mode, the pid argument is used to pass the fd
10621 * opened to the cgroup directory in cgroupfs. The cpu argument
10622 * designates the cpu on which to monitor threads from that
10625 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
10628 if (flags & PERF_FLAG_FD_CLOEXEC)
10629 f_flags |= O_CLOEXEC;
10631 event_fd = get_unused_fd_flags(f_flags);
10635 if (group_fd != -1) {
10636 err = perf_fget_light(group_fd, &group);
10639 group_leader = group.file->private_data;
10640 if (flags & PERF_FLAG_FD_OUTPUT)
10641 output_event = group_leader;
10642 if (flags & PERF_FLAG_FD_NO_GROUP)
10643 group_leader = NULL;
10646 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
10647 task = find_lively_task_by_vpid(pid);
10648 if (IS_ERR(task)) {
10649 err = PTR_ERR(task);
10654 if (task && group_leader &&
10655 group_leader->attr.inherit != attr.inherit) {
10661 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
10666 * Reuse ptrace permission checks for now.
10668 * We must hold cred_guard_mutex across this and any potential
10669 * perf_install_in_context() call for this new event to
10670 * serialize against exec() altering our credentials (and the
10671 * perf_event_exit_task() that could imply).
10674 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
10678 if (flags & PERF_FLAG_PID_CGROUP)
10681 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10682 NULL, NULL, cgroup_fd);
10683 if (IS_ERR(event)) {
10684 err = PTR_ERR(event);
10688 if (is_sampling_event(event)) {
10689 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
10696 * Special case software events and allow them to be part of
10697 * any hardware group.
10701 if (attr.use_clockid) {
10702 err = perf_event_set_clock(event, attr.clockid);
10707 if (pmu->task_ctx_nr == perf_sw_context)
10708 event->event_caps |= PERF_EV_CAP_SOFTWARE;
10710 if (group_leader) {
10711 if (is_software_event(event) &&
10712 !in_software_context(group_leader)) {
10714 * If the event is a sw event, but the group_leader
10715 * is on hw context.
10717 * Allow the addition of software events to hw
10718 * groups, this is safe because software events
10719 * never fail to schedule.
10721 pmu = group_leader->ctx->pmu;
10722 } else if (!is_software_event(event) &&
10723 is_software_event(group_leader) &&
10724 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10726 * In case the group is a pure software group, and we
10727 * try to add a hardware event, move the whole group to
10728 * the hardware context.
10735 * Get the target context (task or percpu):
10737 ctx = find_get_context(pmu, task, event);
10739 err = PTR_ERR(ctx);
10744 * Look up the group leader (we will attach this event to it):
10746 if (group_leader) {
10750 * Do not allow a recursive hierarchy (this new sibling
10751 * becoming part of another group-sibling):
10753 if (group_leader->group_leader != group_leader)
10756 /* All events in a group should have the same clock */
10757 if (group_leader->clock != event->clock)
10761 * Make sure we're both events for the same CPU;
10762 * grouping events for different CPUs is broken; since
10763 * you can never concurrently schedule them anyhow.
10765 if (group_leader->cpu != event->cpu)
10769 * Make sure we're both on the same task, or both
10772 if (group_leader->ctx->task != ctx->task)
10776 * Do not allow to attach to a group in a different task
10777 * or CPU context. If we're moving SW events, we'll fix
10778 * this up later, so allow that.
10780 if (!move_group && group_leader->ctx != ctx)
10784 * Only a group leader can be exclusive or pinned
10786 if (attr.exclusive || attr.pinned)
10790 if (output_event) {
10791 err = perf_event_set_output(event, output_event);
10796 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10798 if (IS_ERR(event_file)) {
10799 err = PTR_ERR(event_file);
10805 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10807 if (gctx->task == TASK_TOMBSTONE) {
10813 * Check if we raced against another sys_perf_event_open() call
10814 * moving the software group underneath us.
10816 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10818 * If someone moved the group out from under us, check
10819 * if this new event wound up on the same ctx, if so
10820 * its the regular !move_group case, otherwise fail.
10826 perf_event_ctx_unlock(group_leader, gctx);
10832 * Failure to create exclusive events returns -EBUSY.
10835 if (!exclusive_event_installable(group_leader, ctx))
10838 for_each_sibling_event(sibling, group_leader) {
10839 if (!exclusive_event_installable(sibling, ctx))
10843 mutex_lock(&ctx->mutex);
10846 if (ctx->task == TASK_TOMBSTONE) {
10851 if (!perf_event_validate_size(event)) {
10858 * Check if the @cpu we're creating an event for is online.
10860 * We use the perf_cpu_context::ctx::mutex to serialize against
10861 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10863 struct perf_cpu_context *cpuctx =
10864 container_of(ctx, struct perf_cpu_context, ctx);
10866 if (!cpuctx->online) {
10874 * Must be under the same ctx::mutex as perf_install_in_context(),
10875 * because we need to serialize with concurrent event creation.
10877 if (!exclusive_event_installable(event, ctx)) {
10882 WARN_ON_ONCE(ctx->parent_ctx);
10885 * This is the point on no return; we cannot fail hereafter. This is
10886 * where we start modifying current state.
10891 * See perf_event_ctx_lock() for comments on the details
10892 * of swizzling perf_event::ctx.
10894 perf_remove_from_context(group_leader, 0);
10897 for_each_sibling_event(sibling, group_leader) {
10898 perf_remove_from_context(sibling, 0);
10903 * Wait for everybody to stop referencing the events through
10904 * the old lists, before installing it on new lists.
10909 * Install the group siblings before the group leader.
10911 * Because a group leader will try and install the entire group
10912 * (through the sibling list, which is still in-tact), we can
10913 * end up with siblings installed in the wrong context.
10915 * By installing siblings first we NO-OP because they're not
10916 * reachable through the group lists.
10918 for_each_sibling_event(sibling, group_leader) {
10919 perf_event__state_init(sibling);
10920 perf_install_in_context(ctx, sibling, sibling->cpu);
10925 * Removing from the context ends up with disabled
10926 * event. What we want here is event in the initial
10927 * startup state, ready to be add into new context.
10929 perf_event__state_init(group_leader);
10930 perf_install_in_context(ctx, group_leader, group_leader->cpu);
10935 * Precalculate sample_data sizes; do while holding ctx::mutex such
10936 * that we're serialized against further additions and before
10937 * perf_install_in_context() which is the point the event is active and
10938 * can use these values.
10940 perf_event__header_size(event);
10941 perf_event__id_header_size(event);
10943 event->owner = current;
10945 perf_install_in_context(ctx, event, event->cpu);
10946 perf_unpin_context(ctx);
10949 perf_event_ctx_unlock(group_leader, gctx);
10950 mutex_unlock(&ctx->mutex);
10953 mutex_unlock(&task->signal->cred_guard_mutex);
10954 put_task_struct(task);
10957 mutex_lock(¤t->perf_event_mutex);
10958 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10959 mutex_unlock(¤t->perf_event_mutex);
10962 * Drop the reference on the group_event after placing the
10963 * new event on the sibling_list. This ensures destruction
10964 * of the group leader will find the pointer to itself in
10965 * perf_group_detach().
10968 fd_install(event_fd, event_file);
10973 perf_event_ctx_unlock(group_leader, gctx);
10974 mutex_unlock(&ctx->mutex);
10978 perf_unpin_context(ctx);
10982 * If event_file is set, the fput() above will have called ->release()
10983 * and that will take care of freeing the event.
10989 mutex_unlock(&task->signal->cred_guard_mutex);
10992 put_task_struct(task);
10996 put_unused_fd(event_fd);
11001 * perf_event_create_kernel_counter
11003 * @attr: attributes of the counter to create
11004 * @cpu: cpu in which the counter is bound
11005 * @task: task to profile (NULL for percpu)
11007 struct perf_event *
11008 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
11009 struct task_struct *task,
11010 perf_overflow_handler_t overflow_handler,
11013 struct perf_event_context *ctx;
11014 struct perf_event *event;
11018 * Get the target context (task or percpu):
11021 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
11022 overflow_handler, context, -1);
11023 if (IS_ERR(event)) {
11024 err = PTR_ERR(event);
11028 /* Mark owner so we could distinguish it from user events. */
11029 event->owner = TASK_TOMBSTONE;
11031 ctx = find_get_context(event->pmu, task, event);
11033 err = PTR_ERR(ctx);
11037 WARN_ON_ONCE(ctx->parent_ctx);
11038 mutex_lock(&ctx->mutex);
11039 if (ctx->task == TASK_TOMBSTONE) {
11046 * Check if the @cpu we're creating an event for is online.
11048 * We use the perf_cpu_context::ctx::mutex to serialize against
11049 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11051 struct perf_cpu_context *cpuctx =
11052 container_of(ctx, struct perf_cpu_context, ctx);
11053 if (!cpuctx->online) {
11059 if (!exclusive_event_installable(event, ctx)) {
11064 perf_install_in_context(ctx, event, event->cpu);
11065 perf_unpin_context(ctx);
11066 mutex_unlock(&ctx->mutex);
11071 mutex_unlock(&ctx->mutex);
11072 perf_unpin_context(ctx);
11077 return ERR_PTR(err);
11079 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
11081 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
11083 struct perf_event_context *src_ctx;
11084 struct perf_event_context *dst_ctx;
11085 struct perf_event *event, *tmp;
11088 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
11089 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
11092 * See perf_event_ctx_lock() for comments on the details
11093 * of swizzling perf_event::ctx.
11095 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
11096 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
11098 perf_remove_from_context(event, 0);
11099 unaccount_event_cpu(event, src_cpu);
11101 list_add(&event->migrate_entry, &events);
11105 * Wait for the events to quiesce before re-instating them.
11110 * Re-instate events in 2 passes.
11112 * Skip over group leaders and only install siblings on this first
11113 * pass, siblings will not get enabled without a leader, however a
11114 * leader will enable its siblings, even if those are still on the old
11117 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11118 if (event->group_leader == event)
11121 list_del(&event->migrate_entry);
11122 if (event->state >= PERF_EVENT_STATE_OFF)
11123 event->state = PERF_EVENT_STATE_INACTIVE;
11124 account_event_cpu(event, dst_cpu);
11125 perf_install_in_context(dst_ctx, event, dst_cpu);
11130 * Once all the siblings are setup properly, install the group leaders
11133 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11134 list_del(&event->migrate_entry);
11135 if (event->state >= PERF_EVENT_STATE_OFF)
11136 event->state = PERF_EVENT_STATE_INACTIVE;
11137 account_event_cpu(event, dst_cpu);
11138 perf_install_in_context(dst_ctx, event, dst_cpu);
11141 mutex_unlock(&dst_ctx->mutex);
11142 mutex_unlock(&src_ctx->mutex);
11144 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
11146 static void sync_child_event(struct perf_event *child_event,
11147 struct task_struct *child)
11149 struct perf_event *parent_event = child_event->parent;
11152 if (child_event->attr.inherit_stat)
11153 perf_event_read_event(child_event, child);
11155 child_val = perf_event_count(child_event);
11158 * Add back the child's count to the parent's count:
11160 atomic64_add(child_val, &parent_event->child_count);
11161 atomic64_add(child_event->total_time_enabled,
11162 &parent_event->child_total_time_enabled);
11163 atomic64_add(child_event->total_time_running,
11164 &parent_event->child_total_time_running);
11168 perf_event_exit_event(struct perf_event *child_event,
11169 struct perf_event_context *child_ctx,
11170 struct task_struct *child)
11172 struct perf_event *parent_event = child_event->parent;
11175 * Do not destroy the 'original' grouping; because of the context
11176 * switch optimization the original events could've ended up in a
11177 * random child task.
11179 * If we were to destroy the original group, all group related
11180 * operations would cease to function properly after this random
11183 * Do destroy all inherited groups, we don't care about those
11184 * and being thorough is better.
11186 raw_spin_lock_irq(&child_ctx->lock);
11187 WARN_ON_ONCE(child_ctx->is_active);
11190 perf_group_detach(child_event);
11191 list_del_event(child_event, child_ctx);
11192 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
11193 raw_spin_unlock_irq(&child_ctx->lock);
11196 * Parent events are governed by their filedesc, retain them.
11198 if (!parent_event) {
11199 perf_event_wakeup(child_event);
11203 * Child events can be cleaned up.
11206 sync_child_event(child_event, child);
11209 * Remove this event from the parent's list
11211 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
11212 mutex_lock(&parent_event->child_mutex);
11213 list_del_init(&child_event->child_list);
11214 mutex_unlock(&parent_event->child_mutex);
11217 * Kick perf_poll() for is_event_hup().
11219 perf_event_wakeup(parent_event);
11220 free_event(child_event);
11221 put_event(parent_event);
11224 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
11226 struct perf_event_context *child_ctx, *clone_ctx = NULL;
11227 struct perf_event *child_event, *next;
11229 WARN_ON_ONCE(child != current);
11231 child_ctx = perf_pin_task_context(child, ctxn);
11236 * In order to reduce the amount of tricky in ctx tear-down, we hold
11237 * ctx::mutex over the entire thing. This serializes against almost
11238 * everything that wants to access the ctx.
11240 * The exception is sys_perf_event_open() /
11241 * perf_event_create_kernel_count() which does find_get_context()
11242 * without ctx::mutex (it cannot because of the move_group double mutex
11243 * lock thing). See the comments in perf_install_in_context().
11245 mutex_lock(&child_ctx->mutex);
11248 * In a single ctx::lock section, de-schedule the events and detach the
11249 * context from the task such that we cannot ever get it scheduled back
11252 raw_spin_lock_irq(&child_ctx->lock);
11253 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
11256 * Now that the context is inactive, destroy the task <-> ctx relation
11257 * and mark the context dead.
11259 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
11260 put_ctx(child_ctx); /* cannot be last */
11261 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
11262 put_task_struct(current); /* cannot be last */
11264 clone_ctx = unclone_ctx(child_ctx);
11265 raw_spin_unlock_irq(&child_ctx->lock);
11268 put_ctx(clone_ctx);
11271 * Report the task dead after unscheduling the events so that we
11272 * won't get any samples after PERF_RECORD_EXIT. We can however still
11273 * get a few PERF_RECORD_READ events.
11275 perf_event_task(child, child_ctx, 0);
11277 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
11278 perf_event_exit_event(child_event, child_ctx, child);
11280 mutex_unlock(&child_ctx->mutex);
11282 put_ctx(child_ctx);
11286 * When a child task exits, feed back event values to parent events.
11288 * Can be called with cred_guard_mutex held when called from
11289 * install_exec_creds().
11291 void perf_event_exit_task(struct task_struct *child)
11293 struct perf_event *event, *tmp;
11296 mutex_lock(&child->perf_event_mutex);
11297 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
11299 list_del_init(&event->owner_entry);
11302 * Ensure the list deletion is visible before we clear
11303 * the owner, closes a race against perf_release() where
11304 * we need to serialize on the owner->perf_event_mutex.
11306 smp_store_release(&event->owner, NULL);
11308 mutex_unlock(&child->perf_event_mutex);
11310 for_each_task_context_nr(ctxn)
11311 perf_event_exit_task_context(child, ctxn);
11314 * The perf_event_exit_task_context calls perf_event_task
11315 * with child's task_ctx, which generates EXIT events for
11316 * child contexts and sets child->perf_event_ctxp[] to NULL.
11317 * At this point we need to send EXIT events to cpu contexts.
11319 perf_event_task(child, NULL, 0);
11322 static void perf_free_event(struct perf_event *event,
11323 struct perf_event_context *ctx)
11325 struct perf_event *parent = event->parent;
11327 if (WARN_ON_ONCE(!parent))
11330 mutex_lock(&parent->child_mutex);
11331 list_del_init(&event->child_list);
11332 mutex_unlock(&parent->child_mutex);
11336 raw_spin_lock_irq(&ctx->lock);
11337 perf_group_detach(event);
11338 list_del_event(event, ctx);
11339 raw_spin_unlock_irq(&ctx->lock);
11344 * Free a context as created by inheritance by perf_event_init_task() below,
11345 * used by fork() in case of fail.
11347 * Even though the task has never lived, the context and events have been
11348 * exposed through the child_list, so we must take care tearing it all down.
11350 void perf_event_free_task(struct task_struct *task)
11352 struct perf_event_context *ctx;
11353 struct perf_event *event, *tmp;
11356 for_each_task_context_nr(ctxn) {
11357 ctx = task->perf_event_ctxp[ctxn];
11361 mutex_lock(&ctx->mutex);
11362 raw_spin_lock_irq(&ctx->lock);
11364 * Destroy the task <-> ctx relation and mark the context dead.
11366 * This is important because even though the task hasn't been
11367 * exposed yet the context has been (through child_list).
11369 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
11370 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
11371 put_task_struct(task); /* cannot be last */
11372 raw_spin_unlock_irq(&ctx->lock);
11374 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
11375 perf_free_event(event, ctx);
11377 mutex_unlock(&ctx->mutex);
11380 * perf_event_release_kernel() could've stolen some of our
11381 * child events and still have them on its free_list. In that
11382 * case we must wait for these events to have been freed (in
11383 * particular all their references to this task must've been
11386 * Without this copy_process() will unconditionally free this
11387 * task (irrespective of its reference count) and
11388 * _free_event()'s put_task_struct(event->hw.target) will be a
11391 * Wait for all events to drop their context reference.
11393 wait_var_event(&ctx->refcount, atomic_read(&ctx->refcount) == 1);
11394 put_ctx(ctx); /* must be last */
11398 void perf_event_delayed_put(struct task_struct *task)
11402 for_each_task_context_nr(ctxn)
11403 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
11406 struct file *perf_event_get(unsigned int fd)
11410 file = fget_raw(fd);
11412 return ERR_PTR(-EBADF);
11414 if (file->f_op != &perf_fops) {
11416 return ERR_PTR(-EBADF);
11422 const struct perf_event *perf_get_event(struct file *file)
11424 if (file->f_op != &perf_fops)
11425 return ERR_PTR(-EINVAL);
11427 return file->private_data;
11430 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
11433 return ERR_PTR(-EINVAL);
11435 return &event->attr;
11439 * Inherit an event from parent task to child task.
11442 * - valid pointer on success
11443 * - NULL for orphaned events
11444 * - IS_ERR() on error
11446 static struct perf_event *
11447 inherit_event(struct perf_event *parent_event,
11448 struct task_struct *parent,
11449 struct perf_event_context *parent_ctx,
11450 struct task_struct *child,
11451 struct perf_event *group_leader,
11452 struct perf_event_context *child_ctx)
11454 enum perf_event_state parent_state = parent_event->state;
11455 struct perf_event *child_event;
11456 unsigned long flags;
11459 * Instead of creating recursive hierarchies of events,
11460 * we link inherited events back to the original parent,
11461 * which has a filp for sure, which we use as the reference
11464 if (parent_event->parent)
11465 parent_event = parent_event->parent;
11467 child_event = perf_event_alloc(&parent_event->attr,
11470 group_leader, parent_event,
11472 if (IS_ERR(child_event))
11473 return child_event;
11476 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
11477 !child_ctx->task_ctx_data) {
11478 struct pmu *pmu = child_event->pmu;
11480 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
11482 if (!child_ctx->task_ctx_data) {
11483 free_event(child_event);
11484 return ERR_PTR(-ENOMEM);
11489 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
11490 * must be under the same lock in order to serialize against
11491 * perf_event_release_kernel(), such that either we must observe
11492 * is_orphaned_event() or they will observe us on the child_list.
11494 mutex_lock(&parent_event->child_mutex);
11495 if (is_orphaned_event(parent_event) ||
11496 !atomic_long_inc_not_zero(&parent_event->refcount)) {
11497 mutex_unlock(&parent_event->child_mutex);
11498 /* task_ctx_data is freed with child_ctx */
11499 free_event(child_event);
11503 get_ctx(child_ctx);
11506 * Make the child state follow the state of the parent event,
11507 * not its attr.disabled bit. We hold the parent's mutex,
11508 * so we won't race with perf_event_{en, dis}able_family.
11510 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
11511 child_event->state = PERF_EVENT_STATE_INACTIVE;
11513 child_event->state = PERF_EVENT_STATE_OFF;
11515 if (parent_event->attr.freq) {
11516 u64 sample_period = parent_event->hw.sample_period;
11517 struct hw_perf_event *hwc = &child_event->hw;
11519 hwc->sample_period = sample_period;
11520 hwc->last_period = sample_period;
11522 local64_set(&hwc->period_left, sample_period);
11525 child_event->ctx = child_ctx;
11526 child_event->overflow_handler = parent_event->overflow_handler;
11527 child_event->overflow_handler_context
11528 = parent_event->overflow_handler_context;
11531 * Precalculate sample_data sizes
11533 perf_event__header_size(child_event);
11534 perf_event__id_header_size(child_event);
11537 * Link it up in the child's context:
11539 raw_spin_lock_irqsave(&child_ctx->lock, flags);
11540 add_event_to_ctx(child_event, child_ctx);
11541 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
11544 * Link this into the parent event's child list
11546 list_add_tail(&child_event->child_list, &parent_event->child_list);
11547 mutex_unlock(&parent_event->child_mutex);
11549 return child_event;
11553 * Inherits an event group.
11555 * This will quietly suppress orphaned events; !inherit_event() is not an error.
11556 * This matches with perf_event_release_kernel() removing all child events.
11562 static int inherit_group(struct perf_event *parent_event,
11563 struct task_struct *parent,
11564 struct perf_event_context *parent_ctx,
11565 struct task_struct *child,
11566 struct perf_event_context *child_ctx)
11568 struct perf_event *leader;
11569 struct perf_event *sub;
11570 struct perf_event *child_ctr;
11572 leader = inherit_event(parent_event, parent, parent_ctx,
11573 child, NULL, child_ctx);
11574 if (IS_ERR(leader))
11575 return PTR_ERR(leader);
11577 * @leader can be NULL here because of is_orphaned_event(). In this
11578 * case inherit_event() will create individual events, similar to what
11579 * perf_group_detach() would do anyway.
11581 for_each_sibling_event(sub, parent_event) {
11582 child_ctr = inherit_event(sub, parent, parent_ctx,
11583 child, leader, child_ctx);
11584 if (IS_ERR(child_ctr))
11585 return PTR_ERR(child_ctr);
11591 * Creates the child task context and tries to inherit the event-group.
11593 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
11594 * inherited_all set when we 'fail' to inherit an orphaned event; this is
11595 * consistent with perf_event_release_kernel() removing all child events.
11602 inherit_task_group(struct perf_event *event, struct task_struct *parent,
11603 struct perf_event_context *parent_ctx,
11604 struct task_struct *child, int ctxn,
11605 int *inherited_all)
11608 struct perf_event_context *child_ctx;
11610 if (!event->attr.inherit) {
11611 *inherited_all = 0;
11615 child_ctx = child->perf_event_ctxp[ctxn];
11618 * This is executed from the parent task context, so
11619 * inherit events that have been marked for cloning.
11620 * First allocate and initialize a context for the
11623 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
11627 child->perf_event_ctxp[ctxn] = child_ctx;
11630 ret = inherit_group(event, parent, parent_ctx,
11634 *inherited_all = 0;
11640 * Initialize the perf_event context in task_struct
11642 static int perf_event_init_context(struct task_struct *child, int ctxn)
11644 struct perf_event_context *child_ctx, *parent_ctx;
11645 struct perf_event_context *cloned_ctx;
11646 struct perf_event *event;
11647 struct task_struct *parent = current;
11648 int inherited_all = 1;
11649 unsigned long flags;
11652 if (likely(!parent->perf_event_ctxp[ctxn]))
11656 * If the parent's context is a clone, pin it so it won't get
11657 * swapped under us.
11659 parent_ctx = perf_pin_task_context(parent, ctxn);
11664 * No need to check if parent_ctx != NULL here; since we saw
11665 * it non-NULL earlier, the only reason for it to become NULL
11666 * is if we exit, and since we're currently in the middle of
11667 * a fork we can't be exiting at the same time.
11671 * Lock the parent list. No need to lock the child - not PID
11672 * hashed yet and not running, so nobody can access it.
11674 mutex_lock(&parent_ctx->mutex);
11677 * We dont have to disable NMIs - we are only looking at
11678 * the list, not manipulating it:
11680 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
11681 ret = inherit_task_group(event, parent, parent_ctx,
11682 child, ctxn, &inherited_all);
11688 * We can't hold ctx->lock when iterating the ->flexible_group list due
11689 * to allocations, but we need to prevent rotation because
11690 * rotate_ctx() will change the list from interrupt context.
11692 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11693 parent_ctx->rotate_disable = 1;
11694 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11696 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
11697 ret = inherit_task_group(event, parent, parent_ctx,
11698 child, ctxn, &inherited_all);
11703 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11704 parent_ctx->rotate_disable = 0;
11706 child_ctx = child->perf_event_ctxp[ctxn];
11708 if (child_ctx && inherited_all) {
11710 * Mark the child context as a clone of the parent
11711 * context, or of whatever the parent is a clone of.
11713 * Note that if the parent is a clone, the holding of
11714 * parent_ctx->lock avoids it from being uncloned.
11716 cloned_ctx = parent_ctx->parent_ctx;
11718 child_ctx->parent_ctx = cloned_ctx;
11719 child_ctx->parent_gen = parent_ctx->parent_gen;
11721 child_ctx->parent_ctx = parent_ctx;
11722 child_ctx->parent_gen = parent_ctx->generation;
11724 get_ctx(child_ctx->parent_ctx);
11727 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11729 mutex_unlock(&parent_ctx->mutex);
11731 perf_unpin_context(parent_ctx);
11732 put_ctx(parent_ctx);
11738 * Initialize the perf_event context in task_struct
11740 int perf_event_init_task(struct task_struct *child)
11744 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
11745 mutex_init(&child->perf_event_mutex);
11746 INIT_LIST_HEAD(&child->perf_event_list);
11748 for_each_task_context_nr(ctxn) {
11749 ret = perf_event_init_context(child, ctxn);
11751 perf_event_free_task(child);
11759 static void __init perf_event_init_all_cpus(void)
11761 struct swevent_htable *swhash;
11764 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
11766 for_each_possible_cpu(cpu) {
11767 swhash = &per_cpu(swevent_htable, cpu);
11768 mutex_init(&swhash->hlist_mutex);
11769 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
11771 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
11772 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
11774 #ifdef CONFIG_CGROUP_PERF
11775 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
11777 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
11781 void perf_swevent_init_cpu(unsigned int cpu)
11783 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
11785 mutex_lock(&swhash->hlist_mutex);
11786 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11787 struct swevent_hlist *hlist;
11789 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11791 rcu_assign_pointer(swhash->swevent_hlist, hlist);
11793 mutex_unlock(&swhash->hlist_mutex);
11796 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11797 static void __perf_event_exit_context(void *__info)
11799 struct perf_event_context *ctx = __info;
11800 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11801 struct perf_event *event;
11803 raw_spin_lock(&ctx->lock);
11804 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
11805 list_for_each_entry(event, &ctx->event_list, event_entry)
11806 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11807 raw_spin_unlock(&ctx->lock);
11810 static void perf_event_exit_cpu_context(int cpu)
11812 struct perf_cpu_context *cpuctx;
11813 struct perf_event_context *ctx;
11816 mutex_lock(&pmus_lock);
11817 list_for_each_entry(pmu, &pmus, entry) {
11818 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11819 ctx = &cpuctx->ctx;
11821 mutex_lock(&ctx->mutex);
11822 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11823 cpuctx->online = 0;
11824 mutex_unlock(&ctx->mutex);
11826 cpumask_clear_cpu(cpu, perf_online_mask);
11827 mutex_unlock(&pmus_lock);
11831 static void perf_event_exit_cpu_context(int cpu) { }
11835 int perf_event_init_cpu(unsigned int cpu)
11837 struct perf_cpu_context *cpuctx;
11838 struct perf_event_context *ctx;
11841 perf_swevent_init_cpu(cpu);
11843 mutex_lock(&pmus_lock);
11844 cpumask_set_cpu(cpu, perf_online_mask);
11845 list_for_each_entry(pmu, &pmus, entry) {
11846 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11847 ctx = &cpuctx->ctx;
11849 mutex_lock(&ctx->mutex);
11850 cpuctx->online = 1;
11851 mutex_unlock(&ctx->mutex);
11853 mutex_unlock(&pmus_lock);
11858 int perf_event_exit_cpu(unsigned int cpu)
11860 perf_event_exit_cpu_context(cpu);
11865 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11869 for_each_online_cpu(cpu)
11870 perf_event_exit_cpu(cpu);
11876 * Run the perf reboot notifier at the very last possible moment so that
11877 * the generic watchdog code runs as long as possible.
11879 static struct notifier_block perf_reboot_notifier = {
11880 .notifier_call = perf_reboot,
11881 .priority = INT_MIN,
11884 void __init perf_event_init(void)
11888 idr_init(&pmu_idr);
11890 perf_event_init_all_cpus();
11891 init_srcu_struct(&pmus_srcu);
11892 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11893 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11894 perf_pmu_register(&perf_task_clock, NULL, -1);
11895 perf_tp_register();
11896 perf_event_init_cpu(smp_processor_id());
11897 register_reboot_notifier(&perf_reboot_notifier);
11899 ret = init_hw_breakpoint();
11900 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11903 * Build time assertion that we keep the data_head at the intended
11904 * location. IOW, validation we got the __reserved[] size right.
11906 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11910 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
11913 struct perf_pmu_events_attr *pmu_attr =
11914 container_of(attr, struct perf_pmu_events_attr, attr);
11916 if (pmu_attr->event_str)
11917 return sprintf(page, "%s\n", pmu_attr->event_str);
11921 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
11923 static int __init perf_event_sysfs_init(void)
11928 mutex_lock(&pmus_lock);
11930 ret = bus_register(&pmu_bus);
11934 list_for_each_entry(pmu, &pmus, entry) {
11935 if (!pmu->name || pmu->type < 0)
11938 ret = pmu_dev_alloc(pmu);
11939 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
11941 pmu_bus_running = 1;
11945 mutex_unlock(&pmus_lock);
11949 device_initcall(perf_event_sysfs_init);
11951 #ifdef CONFIG_CGROUP_PERF
11952 static struct cgroup_subsys_state *
11953 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
11955 struct perf_cgroup *jc;
11957 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
11959 return ERR_PTR(-ENOMEM);
11961 jc->info = alloc_percpu(struct perf_cgroup_info);
11964 return ERR_PTR(-ENOMEM);
11970 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
11972 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
11974 free_percpu(jc->info);
11978 static int __perf_cgroup_move(void *info)
11980 struct task_struct *task = info;
11982 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
11987 static void perf_cgroup_attach(struct cgroup_taskset *tset)
11989 struct task_struct *task;
11990 struct cgroup_subsys_state *css;
11992 cgroup_taskset_for_each(task, css, tset)
11993 task_function_call(task, __perf_cgroup_move, task);
11996 struct cgroup_subsys perf_event_cgrp_subsys = {
11997 .css_alloc = perf_cgroup_css_alloc,
11998 .css_free = perf_cgroup_css_free,
11999 .attach = perf_cgroup_attach,
12001 * Implicitly enable on dfl hierarchy so that perf events can
12002 * always be filtered by cgroup2 path as long as perf_event
12003 * controller is not mounted on a legacy hierarchy.
12005 .implicit_on_dfl = true,
12008 #endif /* CONFIG_CGROUP_PERF */