2 * Performance events core code:
4 * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
5 * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
6 * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
7 * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 * For licensing details see kernel-base/COPYING
14 #include <linux/cpu.h>
15 #include <linux/smp.h>
16 #include <linux/idr.h>
17 #include <linux/file.h>
18 #include <linux/poll.h>
19 #include <linux/slab.h>
20 #include <linux/hash.h>
21 #include <linux/tick.h>
22 #include <linux/sysfs.h>
23 #include <linux/dcache.h>
24 #include <linux/percpu.h>
25 #include <linux/ptrace.h>
26 #include <linux/reboot.h>
27 #include <linux/vmstat.h>
28 #include <linux/device.h>
29 #include <linux/export.h>
30 #include <linux/vmalloc.h>
31 #include <linux/hardirq.h>
32 #include <linux/rculist.h>
33 #include <linux/uaccess.h>
34 #include <linux/syscalls.h>
35 #include <linux/anon_inodes.h>
36 #include <linux/kernel_stat.h>
37 #include <linux/cgroup.h>
38 #include <linux/perf_event.h>
39 #include <linux/trace_events.h>
40 #include <linux/hw_breakpoint.h>
41 #include <linux/mm_types.h>
42 #include <linux/module.h>
43 #include <linux/mman.h>
44 #include <linux/compat.h>
45 #include <linux/bpf.h>
46 #include <linux/filter.h>
47 #include <linux/namei.h>
48 #include <linux/parser.h>
49 #include <linux/sched/clock.h>
50 #include <linux/sched/mm.h>
51 #include <linux/proc_ns.h>
52 #include <linux/mount.h>
56 #include <asm/irq_regs.h>
58 typedef int (*remote_function_f)(void *);
60 struct remote_function_call {
61 struct task_struct *p;
62 remote_function_f func;
67 static void remote_function(void *data)
69 struct remote_function_call *tfc = data;
70 struct task_struct *p = tfc->p;
74 if (task_cpu(p) != smp_processor_id())
78 * Now that we're on right CPU with IRQs disabled, we can test
79 * if we hit the right task without races.
82 tfc->ret = -ESRCH; /* No such (running) process */
87 tfc->ret = tfc->func(tfc->info);
91 * task_function_call - call a function on the cpu on which a task runs
92 * @p: the task to evaluate
93 * @func: the function to be called
94 * @info: the function call argument
96 * Calls the function @func when the task is currently running. This might
97 * be on the current CPU, which just calls the function directly. This will
98 * retry due to any failures in smp_call_function_single(), such as if the
99 * task_cpu() goes offline concurrently.
101 * returns @func return value or -ESRCH or -ENXIO when the process isn't running
104 task_function_call(struct task_struct *p, remote_function_f func, void *info)
106 struct remote_function_call data = {
115 ret = smp_call_function_single(task_cpu(p), remote_function,
130 * cpu_function_call - call a function on the cpu
131 * @func: the function to be called
132 * @info: the function call argument
134 * Calls the function @func on the remote cpu.
136 * returns: @func return value or -ENXIO when the cpu is offline
138 static int cpu_function_call(int cpu, remote_function_f func, void *info)
140 struct remote_function_call data = {
144 .ret = -ENXIO, /* No such CPU */
147 smp_call_function_single(cpu, remote_function, &data, 1);
152 static inline struct perf_cpu_context *
153 __get_cpu_context(struct perf_event_context *ctx)
155 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
158 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
159 struct perf_event_context *ctx)
161 raw_spin_lock(&cpuctx->ctx.lock);
163 raw_spin_lock(&ctx->lock);
166 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
167 struct perf_event_context *ctx)
170 raw_spin_unlock(&ctx->lock);
171 raw_spin_unlock(&cpuctx->ctx.lock);
174 #define TASK_TOMBSTONE ((void *)-1L)
176 static bool is_kernel_event(struct perf_event *event)
178 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
182 * On task ctx scheduling...
184 * When !ctx->nr_events a task context will not be scheduled. This means
185 * we can disable the scheduler hooks (for performance) without leaving
186 * pending task ctx state.
188 * This however results in two special cases:
190 * - removing the last event from a task ctx; this is relatively straight
191 * forward and is done in __perf_remove_from_context.
193 * - adding the first event to a task ctx; this is tricky because we cannot
194 * rely on ctx->is_active and therefore cannot use event_function_call().
195 * See perf_install_in_context().
197 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
200 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
201 struct perf_event_context *, void *);
203 struct event_function_struct {
204 struct perf_event *event;
209 static int event_function(void *info)
211 struct event_function_struct *efs = info;
212 struct perf_event *event = efs->event;
213 struct perf_event_context *ctx = event->ctx;
214 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
215 struct perf_event_context *task_ctx = cpuctx->task_ctx;
218 lockdep_assert_irqs_disabled();
220 perf_ctx_lock(cpuctx, task_ctx);
222 * Since we do the IPI call without holding ctx->lock things can have
223 * changed, double check we hit the task we set out to hit.
226 if (ctx->task != current) {
232 * We only use event_function_call() on established contexts,
233 * and event_function() is only ever called when active (or
234 * rather, we'll have bailed in task_function_call() or the
235 * above ctx->task != current test), therefore we must have
236 * ctx->is_active here.
238 WARN_ON_ONCE(!ctx->is_active);
240 * And since we have ctx->is_active, cpuctx->task_ctx must
243 WARN_ON_ONCE(task_ctx != ctx);
245 WARN_ON_ONCE(&cpuctx->ctx != ctx);
248 efs->func(event, cpuctx, ctx, efs->data);
250 perf_ctx_unlock(cpuctx, task_ctx);
255 static void event_function_call(struct perf_event *event, event_f func, void *data)
257 struct perf_event_context *ctx = event->ctx;
258 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
259 struct event_function_struct efs = {
265 if (!event->parent) {
267 * If this is a !child event, we must hold ctx::mutex to
268 * stabilize the the event->ctx relation. See
269 * perf_event_ctx_lock().
271 lockdep_assert_held(&ctx->mutex);
275 cpu_function_call(event->cpu, event_function, &efs);
279 if (task == TASK_TOMBSTONE)
283 if (!task_function_call(task, event_function, &efs))
286 raw_spin_lock_irq(&ctx->lock);
288 * Reload the task pointer, it might have been changed by
289 * a concurrent perf_event_context_sched_out().
292 if (task == TASK_TOMBSTONE) {
293 raw_spin_unlock_irq(&ctx->lock);
296 if (ctx->is_active) {
297 raw_spin_unlock_irq(&ctx->lock);
300 func(event, NULL, ctx, data);
301 raw_spin_unlock_irq(&ctx->lock);
305 * Similar to event_function_call() + event_function(), but hard assumes IRQs
306 * are already disabled and we're on the right CPU.
308 static void event_function_local(struct perf_event *event, event_f func, void *data)
310 struct perf_event_context *ctx = event->ctx;
311 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
312 struct task_struct *task = READ_ONCE(ctx->task);
313 struct perf_event_context *task_ctx = NULL;
315 lockdep_assert_irqs_disabled();
318 if (task == TASK_TOMBSTONE)
324 perf_ctx_lock(cpuctx, task_ctx);
327 if (task == TASK_TOMBSTONE)
332 * We must be either inactive or active and the right task,
333 * otherwise we're screwed, since we cannot IPI to somewhere
336 if (ctx->is_active) {
337 if (WARN_ON_ONCE(task != current))
340 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
344 WARN_ON_ONCE(&cpuctx->ctx != ctx);
347 func(event, cpuctx, ctx, data);
349 perf_ctx_unlock(cpuctx, task_ctx);
352 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
353 PERF_FLAG_FD_OUTPUT |\
354 PERF_FLAG_PID_CGROUP |\
355 PERF_FLAG_FD_CLOEXEC)
358 * branch priv levels that need permission checks
360 #define PERF_SAMPLE_BRANCH_PERM_PLM \
361 (PERF_SAMPLE_BRANCH_KERNEL |\
362 PERF_SAMPLE_BRANCH_HV)
365 EVENT_FLEXIBLE = 0x1,
368 /* see ctx_resched() for details */
370 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
374 * perf_sched_events : >0 events exist
375 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
378 static void perf_sched_delayed(struct work_struct *work);
379 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
380 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
381 static DEFINE_MUTEX(perf_sched_mutex);
382 static atomic_t perf_sched_count;
384 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
385 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
386 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
388 static atomic_t nr_mmap_events __read_mostly;
389 static atomic_t nr_comm_events __read_mostly;
390 static atomic_t nr_namespaces_events __read_mostly;
391 static atomic_t nr_task_events __read_mostly;
392 static atomic_t nr_freq_events __read_mostly;
393 static atomic_t nr_switch_events __read_mostly;
395 static LIST_HEAD(pmus);
396 static DEFINE_MUTEX(pmus_lock);
397 static struct srcu_struct pmus_srcu;
398 static cpumask_var_t perf_online_mask;
401 * perf event paranoia level:
402 * -1 - not paranoid at all
403 * 0 - disallow raw tracepoint access for unpriv
404 * 1 - disallow cpu events for unpriv
405 * 2 - disallow kernel profiling for unpriv
407 int sysctl_perf_event_paranoid __read_mostly = 2;
409 /* Minimum for 512 kiB + 1 user control page */
410 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
413 * max perf event sample rate
415 #define DEFAULT_MAX_SAMPLE_RATE 100000
416 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
417 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
419 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
421 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
422 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
424 static int perf_sample_allowed_ns __read_mostly =
425 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
427 static void update_perf_cpu_limits(void)
429 u64 tmp = perf_sample_period_ns;
431 tmp *= sysctl_perf_cpu_time_max_percent;
432 tmp = div_u64(tmp, 100);
436 WRITE_ONCE(perf_sample_allowed_ns, tmp);
439 static bool perf_rotate_context(struct perf_cpu_context *cpuctx);
441 int perf_proc_update_handler(struct ctl_table *table, int write,
442 void __user *buffer, size_t *lenp,
446 int perf_cpu = sysctl_perf_cpu_time_max_percent;
448 * If throttling is disabled don't allow the write:
450 if (write && (perf_cpu == 100 || perf_cpu == 0))
453 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
457 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
458 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
459 update_perf_cpu_limits();
464 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
466 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
467 void __user *buffer, size_t *lenp,
470 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
475 if (sysctl_perf_cpu_time_max_percent == 100 ||
476 sysctl_perf_cpu_time_max_percent == 0) {
478 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
479 WRITE_ONCE(perf_sample_allowed_ns, 0);
481 update_perf_cpu_limits();
488 * perf samples are done in some very critical code paths (NMIs).
489 * If they take too much CPU time, the system can lock up and not
490 * get any real work done. This will drop the sample rate when
491 * we detect that events are taking too long.
493 #define NR_ACCUMULATED_SAMPLES 128
494 static DEFINE_PER_CPU(u64, running_sample_length);
496 static u64 __report_avg;
497 static u64 __report_allowed;
499 static void perf_duration_warn(struct irq_work *w)
501 printk_ratelimited(KERN_INFO
502 "perf: interrupt took too long (%lld > %lld), lowering "
503 "kernel.perf_event_max_sample_rate to %d\n",
504 __report_avg, __report_allowed,
505 sysctl_perf_event_sample_rate);
508 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
510 void perf_sample_event_took(u64 sample_len_ns)
512 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
520 /* Decay the counter by 1 average sample. */
521 running_len = __this_cpu_read(running_sample_length);
522 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
523 running_len += sample_len_ns;
524 __this_cpu_write(running_sample_length, running_len);
527 * Note: this will be biased artifically low until we have
528 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
529 * from having to maintain a count.
531 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
532 if (avg_len <= max_len)
535 __report_avg = avg_len;
536 __report_allowed = max_len;
539 * Compute a throttle threshold 25% below the current duration.
541 avg_len += avg_len / 4;
542 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
548 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
549 WRITE_ONCE(max_samples_per_tick, max);
551 sysctl_perf_event_sample_rate = max * HZ;
552 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
554 if (!irq_work_queue(&perf_duration_work)) {
555 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
556 "kernel.perf_event_max_sample_rate to %d\n",
557 __report_avg, __report_allowed,
558 sysctl_perf_event_sample_rate);
562 static atomic64_t perf_event_id;
564 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
565 enum event_type_t event_type);
567 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
568 enum event_type_t event_type,
569 struct task_struct *task);
571 static void update_context_time(struct perf_event_context *ctx);
572 static u64 perf_event_time(struct perf_event *event);
574 void __weak perf_event_print_debug(void) { }
576 extern __weak const char *perf_pmu_name(void)
581 static inline u64 perf_clock(void)
583 return local_clock();
586 static inline u64 perf_event_clock(struct perf_event *event)
588 return event->clock();
592 * State based event timekeeping...
594 * The basic idea is to use event->state to determine which (if any) time
595 * fields to increment with the current delta. This means we only need to
596 * update timestamps when we change state or when they are explicitly requested
599 * Event groups make things a little more complicated, but not terribly so. The
600 * rules for a group are that if the group leader is OFF the entire group is
601 * OFF, irrespecive of what the group member states are. This results in
602 * __perf_effective_state().
604 * A futher ramification is that when a group leader flips between OFF and
605 * !OFF, we need to update all group member times.
608 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
609 * need to make sure the relevant context time is updated before we try and
610 * update our timestamps.
613 static __always_inline enum perf_event_state
614 __perf_effective_state(struct perf_event *event)
616 struct perf_event *leader = event->group_leader;
618 if (leader->state <= PERF_EVENT_STATE_OFF)
619 return leader->state;
624 static __always_inline void
625 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
627 enum perf_event_state state = __perf_effective_state(event);
628 u64 delta = now - event->tstamp;
630 *enabled = event->total_time_enabled;
631 if (state >= PERF_EVENT_STATE_INACTIVE)
634 *running = event->total_time_running;
635 if (state >= PERF_EVENT_STATE_ACTIVE)
639 static void perf_event_update_time(struct perf_event *event)
641 u64 now = perf_event_time(event);
643 __perf_update_times(event, now, &event->total_time_enabled,
644 &event->total_time_running);
648 static void perf_event_update_sibling_time(struct perf_event *leader)
650 struct perf_event *sibling;
652 for_each_sibling_event(sibling, leader)
653 perf_event_update_time(sibling);
657 perf_event_set_state(struct perf_event *event, enum perf_event_state state)
659 if (event->state == state)
662 perf_event_update_time(event);
664 * If a group leader gets enabled/disabled all its siblings
667 if ((event->state < 0) ^ (state < 0))
668 perf_event_update_sibling_time(event);
670 WRITE_ONCE(event->state, state);
673 #ifdef CONFIG_CGROUP_PERF
676 perf_cgroup_match(struct perf_event *event)
678 struct perf_event_context *ctx = event->ctx;
679 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
681 /* @event doesn't care about cgroup */
685 /* wants specific cgroup scope but @cpuctx isn't associated with any */
690 * Cgroup scoping is recursive. An event enabled for a cgroup is
691 * also enabled for all its descendant cgroups. If @cpuctx's
692 * cgroup is a descendant of @event's (the test covers identity
693 * case), it's a match.
695 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
696 event->cgrp->css.cgroup);
699 static inline void perf_detach_cgroup(struct perf_event *event)
701 css_put(&event->cgrp->css);
705 static inline int is_cgroup_event(struct perf_event *event)
707 return event->cgrp != NULL;
710 static inline u64 perf_cgroup_event_time(struct perf_event *event)
712 struct perf_cgroup_info *t;
714 t = per_cpu_ptr(event->cgrp->info, event->cpu);
718 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
720 struct perf_cgroup_info *info;
725 info = this_cpu_ptr(cgrp->info);
727 info->time += now - info->timestamp;
728 info->timestamp = now;
731 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
733 struct perf_cgroup *cgrp = cpuctx->cgrp;
734 struct cgroup_subsys_state *css;
737 for (css = &cgrp->css; css; css = css->parent) {
738 cgrp = container_of(css, struct perf_cgroup, css);
739 __update_cgrp_time(cgrp);
744 static inline void update_cgrp_time_from_event(struct perf_event *event)
746 struct perf_cgroup *cgrp;
749 * ensure we access cgroup data only when needed and
750 * when we know the cgroup is pinned (css_get)
752 if (!is_cgroup_event(event))
755 cgrp = perf_cgroup_from_task(current, event->ctx);
757 * Do not update time when cgroup is not active
759 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
760 __update_cgrp_time(event->cgrp);
764 perf_cgroup_set_timestamp(struct task_struct *task,
765 struct perf_event_context *ctx)
767 struct perf_cgroup *cgrp;
768 struct perf_cgroup_info *info;
769 struct cgroup_subsys_state *css;
772 * ctx->lock held by caller
773 * ensure we do not access cgroup data
774 * unless we have the cgroup pinned (css_get)
776 if (!task || !ctx->nr_cgroups)
779 cgrp = perf_cgroup_from_task(task, ctx);
781 for (css = &cgrp->css; css; css = css->parent) {
782 cgrp = container_of(css, struct perf_cgroup, css);
783 info = this_cpu_ptr(cgrp->info);
784 info->timestamp = ctx->timestamp;
788 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
790 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
791 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
794 * reschedule events based on the cgroup constraint of task.
796 * mode SWOUT : schedule out everything
797 * mode SWIN : schedule in based on cgroup for next
799 static void perf_cgroup_switch(struct task_struct *task, int mode)
801 struct perf_cpu_context *cpuctx, *tmp;
802 struct list_head *list;
806 * Disable interrupts and preemption to avoid this CPU's
807 * cgrp_cpuctx_entry to change under us.
809 local_irq_save(flags);
811 list = this_cpu_ptr(&cgrp_cpuctx_list);
812 list_for_each_entry_safe(cpuctx, tmp, list, cgrp_cpuctx_entry) {
813 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
815 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
816 perf_pmu_disable(cpuctx->ctx.pmu);
818 if (mode & PERF_CGROUP_SWOUT) {
819 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
821 * must not be done before ctxswout due
822 * to event_filter_match() in event_sched_out()
827 if (mode & PERF_CGROUP_SWIN) {
828 WARN_ON_ONCE(cpuctx->cgrp);
830 * set cgrp before ctxsw in to allow
831 * event_filter_match() to not have to pass
833 * we pass the cpuctx->ctx to perf_cgroup_from_task()
834 * because cgorup events are only per-cpu
836 cpuctx->cgrp = perf_cgroup_from_task(task,
838 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
840 perf_pmu_enable(cpuctx->ctx.pmu);
841 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
844 local_irq_restore(flags);
847 static inline void perf_cgroup_sched_out(struct task_struct *task,
848 struct task_struct *next)
850 struct perf_cgroup *cgrp1;
851 struct perf_cgroup *cgrp2 = NULL;
855 * we come here when we know perf_cgroup_events > 0
856 * we do not need to pass the ctx here because we know
857 * we are holding the rcu lock
859 cgrp1 = perf_cgroup_from_task(task, NULL);
860 cgrp2 = perf_cgroup_from_task(next, NULL);
863 * only schedule out current cgroup events if we know
864 * that we are switching to a different cgroup. Otherwise,
865 * do no touch the cgroup events.
868 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
873 static inline void perf_cgroup_sched_in(struct task_struct *prev,
874 struct task_struct *task)
876 struct perf_cgroup *cgrp1;
877 struct perf_cgroup *cgrp2 = NULL;
881 * we come here when we know perf_cgroup_events > 0
882 * we do not need to pass the ctx here because we know
883 * we are holding the rcu lock
885 cgrp1 = perf_cgroup_from_task(task, NULL);
886 cgrp2 = perf_cgroup_from_task(prev, NULL);
889 * only need to schedule in cgroup events if we are changing
890 * cgroup during ctxsw. Cgroup events were not scheduled
891 * out of ctxsw out if that was not the case.
894 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
899 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
900 struct perf_event_attr *attr,
901 struct perf_event *group_leader)
903 struct perf_cgroup *cgrp;
904 struct cgroup_subsys_state *css;
905 struct fd f = fdget(fd);
911 css = css_tryget_online_from_dir(f.file->f_path.dentry,
912 &perf_event_cgrp_subsys);
918 cgrp = container_of(css, struct perf_cgroup, css);
922 * all events in a group must monitor
923 * the same cgroup because a task belongs
924 * to only one perf cgroup at a time
926 if (group_leader && group_leader->cgrp != cgrp) {
927 perf_detach_cgroup(event);
936 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
938 struct perf_cgroup_info *t;
939 t = per_cpu_ptr(event->cgrp->info, event->cpu);
940 event->shadow_ctx_time = now - t->timestamp;
944 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
945 * cleared when last cgroup event is removed.
948 list_update_cgroup_event(struct perf_event *event,
949 struct perf_event_context *ctx, bool add)
951 struct perf_cpu_context *cpuctx;
952 struct list_head *cpuctx_entry;
954 if (!is_cgroup_event(event))
958 * Because cgroup events are always per-cpu events,
959 * this will always be called from the right CPU.
961 cpuctx = __get_cpu_context(ctx);
964 * Since setting cpuctx->cgrp is conditional on the current @cgrp
965 * matching the event's cgroup, we must do this for every new event,
966 * because if the first would mismatch, the second would not try again
967 * and we would leave cpuctx->cgrp unset.
969 if (add && !cpuctx->cgrp) {
970 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
972 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
976 if (add && ctx->nr_cgroups++)
978 else if (!add && --ctx->nr_cgroups)
981 /* no cgroup running */
985 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
987 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
989 list_del(cpuctx_entry);
992 #else /* !CONFIG_CGROUP_PERF */
995 perf_cgroup_match(struct perf_event *event)
1000 static inline void perf_detach_cgroup(struct perf_event *event)
1003 static inline int is_cgroup_event(struct perf_event *event)
1008 static inline void update_cgrp_time_from_event(struct perf_event *event)
1012 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
1016 static inline void perf_cgroup_sched_out(struct task_struct *task,
1017 struct task_struct *next)
1021 static inline void perf_cgroup_sched_in(struct task_struct *prev,
1022 struct task_struct *task)
1026 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1027 struct perf_event_attr *attr,
1028 struct perf_event *group_leader)
1034 perf_cgroup_set_timestamp(struct task_struct *task,
1035 struct perf_event_context *ctx)
1040 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1045 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1049 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1055 list_update_cgroup_event(struct perf_event *event,
1056 struct perf_event_context *ctx, bool add)
1063 * set default to be dependent on timer tick just
1064 * like original code
1066 #define PERF_CPU_HRTIMER (1000 / HZ)
1068 * function must be called with interrupts disabled
1070 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1072 struct perf_cpu_context *cpuctx;
1075 lockdep_assert_irqs_disabled();
1077 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1078 rotations = perf_rotate_context(cpuctx);
1080 raw_spin_lock(&cpuctx->hrtimer_lock);
1082 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1084 cpuctx->hrtimer_active = 0;
1085 raw_spin_unlock(&cpuctx->hrtimer_lock);
1087 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1090 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1092 struct hrtimer *timer = &cpuctx->hrtimer;
1093 struct pmu *pmu = cpuctx->ctx.pmu;
1096 /* no multiplexing needed for SW PMU */
1097 if (pmu->task_ctx_nr == perf_sw_context)
1101 * check default is sane, if not set then force to
1102 * default interval (1/tick)
1104 interval = pmu->hrtimer_interval_ms;
1106 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1108 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1110 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1111 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1112 timer->function = perf_mux_hrtimer_handler;
1115 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1117 struct hrtimer *timer = &cpuctx->hrtimer;
1118 struct pmu *pmu = cpuctx->ctx.pmu;
1119 unsigned long flags;
1121 /* not for SW PMU */
1122 if (pmu->task_ctx_nr == perf_sw_context)
1125 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1126 if (!cpuctx->hrtimer_active) {
1127 cpuctx->hrtimer_active = 1;
1128 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1129 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
1131 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1136 static int perf_mux_hrtimer_restart_ipi(void *arg)
1138 return perf_mux_hrtimer_restart(arg);
1141 void perf_pmu_disable(struct pmu *pmu)
1143 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1145 pmu->pmu_disable(pmu);
1148 void perf_pmu_enable(struct pmu *pmu)
1150 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1152 pmu->pmu_enable(pmu);
1155 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1158 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1159 * perf_event_task_tick() are fully serialized because they're strictly cpu
1160 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1161 * disabled, while perf_event_task_tick is called from IRQ context.
1163 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1165 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1167 lockdep_assert_irqs_disabled();
1169 WARN_ON(!list_empty(&ctx->active_ctx_list));
1171 list_add(&ctx->active_ctx_list, head);
1174 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1176 lockdep_assert_irqs_disabled();
1178 WARN_ON(list_empty(&ctx->active_ctx_list));
1180 list_del_init(&ctx->active_ctx_list);
1183 static void get_ctx(struct perf_event_context *ctx)
1185 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1188 static void free_ctx(struct rcu_head *head)
1190 struct perf_event_context *ctx;
1192 ctx = container_of(head, struct perf_event_context, rcu_head);
1193 kfree(ctx->task_ctx_data);
1197 static void put_ctx(struct perf_event_context *ctx)
1199 if (atomic_dec_and_test(&ctx->refcount)) {
1200 if (ctx->parent_ctx)
1201 put_ctx(ctx->parent_ctx);
1202 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1203 put_task_struct(ctx->task);
1204 call_rcu(&ctx->rcu_head, free_ctx);
1209 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1210 * perf_pmu_migrate_context() we need some magic.
1212 * Those places that change perf_event::ctx will hold both
1213 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1215 * Lock ordering is by mutex address. There are two other sites where
1216 * perf_event_context::mutex nests and those are:
1218 * - perf_event_exit_task_context() [ child , 0 ]
1219 * perf_event_exit_event()
1220 * put_event() [ parent, 1 ]
1222 * - perf_event_init_context() [ parent, 0 ]
1223 * inherit_task_group()
1226 * perf_event_alloc()
1228 * perf_try_init_event() [ child , 1 ]
1230 * While it appears there is an obvious deadlock here -- the parent and child
1231 * nesting levels are inverted between the two. This is in fact safe because
1232 * life-time rules separate them. That is an exiting task cannot fork, and a
1233 * spawning task cannot (yet) exit.
1235 * But remember that that these are parent<->child context relations, and
1236 * migration does not affect children, therefore these two orderings should not
1239 * The change in perf_event::ctx does not affect children (as claimed above)
1240 * because the sys_perf_event_open() case will install a new event and break
1241 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1242 * concerned with cpuctx and that doesn't have children.
1244 * The places that change perf_event::ctx will issue:
1246 * perf_remove_from_context();
1247 * synchronize_rcu();
1248 * perf_install_in_context();
1250 * to affect the change. The remove_from_context() + synchronize_rcu() should
1251 * quiesce the event, after which we can install it in the new location. This
1252 * means that only external vectors (perf_fops, prctl) can perturb the event
1253 * while in transit. Therefore all such accessors should also acquire
1254 * perf_event_context::mutex to serialize against this.
1256 * However; because event->ctx can change while we're waiting to acquire
1257 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1262 * task_struct::perf_event_mutex
1263 * perf_event_context::mutex
1264 * perf_event::child_mutex;
1265 * perf_event_context::lock
1266 * perf_event::mmap_mutex
1268 * perf_addr_filters_head::lock
1272 * cpuctx->mutex / perf_event_context::mutex
1274 static struct perf_event_context *
1275 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1277 struct perf_event_context *ctx;
1281 ctx = READ_ONCE(event->ctx);
1282 if (!atomic_inc_not_zero(&ctx->refcount)) {
1288 mutex_lock_nested(&ctx->mutex, nesting);
1289 if (event->ctx != ctx) {
1290 mutex_unlock(&ctx->mutex);
1298 static inline struct perf_event_context *
1299 perf_event_ctx_lock(struct perf_event *event)
1301 return perf_event_ctx_lock_nested(event, 0);
1304 static void perf_event_ctx_unlock(struct perf_event *event,
1305 struct perf_event_context *ctx)
1307 mutex_unlock(&ctx->mutex);
1312 * This must be done under the ctx->lock, such as to serialize against
1313 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1314 * calling scheduler related locks and ctx->lock nests inside those.
1316 static __must_check struct perf_event_context *
1317 unclone_ctx(struct perf_event_context *ctx)
1319 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1321 lockdep_assert_held(&ctx->lock);
1324 ctx->parent_ctx = NULL;
1330 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1335 * only top level events have the pid namespace they were created in
1338 event = event->parent;
1340 nr = __task_pid_nr_ns(p, type, event->ns);
1341 /* avoid -1 if it is idle thread or runs in another ns */
1342 if (!nr && !pid_alive(p))
1347 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1349 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1352 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1354 return perf_event_pid_type(event, p, PIDTYPE_PID);
1358 * If we inherit events we want to return the parent event id
1361 static u64 primary_event_id(struct perf_event *event)
1366 id = event->parent->id;
1372 * Get the perf_event_context for a task and lock it.
1374 * This has to cope with with the fact that until it is locked,
1375 * the context could get moved to another task.
1377 static struct perf_event_context *
1378 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1380 struct perf_event_context *ctx;
1384 * One of the few rules of preemptible RCU is that one cannot do
1385 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1386 * part of the read side critical section was irqs-enabled -- see
1387 * rcu_read_unlock_special().
1389 * Since ctx->lock nests under rq->lock we must ensure the entire read
1390 * side critical section has interrupts disabled.
1392 local_irq_save(*flags);
1394 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1397 * If this context is a clone of another, it might
1398 * get swapped for another underneath us by
1399 * perf_event_task_sched_out, though the
1400 * rcu_read_lock() protects us from any context
1401 * getting freed. Lock the context and check if it
1402 * got swapped before we could get the lock, and retry
1403 * if so. If we locked the right context, then it
1404 * can't get swapped on us any more.
1406 raw_spin_lock(&ctx->lock);
1407 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1408 raw_spin_unlock(&ctx->lock);
1410 local_irq_restore(*flags);
1414 if (ctx->task == TASK_TOMBSTONE ||
1415 !atomic_inc_not_zero(&ctx->refcount)) {
1416 raw_spin_unlock(&ctx->lock);
1419 WARN_ON_ONCE(ctx->task != task);
1424 local_irq_restore(*flags);
1429 * Get the context for a task and increment its pin_count so it
1430 * can't get swapped to another task. This also increments its
1431 * reference count so that the context can't get freed.
1433 static struct perf_event_context *
1434 perf_pin_task_context(struct task_struct *task, int ctxn)
1436 struct perf_event_context *ctx;
1437 unsigned long flags;
1439 ctx = perf_lock_task_context(task, ctxn, &flags);
1442 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1447 static void perf_unpin_context(struct perf_event_context *ctx)
1449 unsigned long flags;
1451 raw_spin_lock_irqsave(&ctx->lock, flags);
1453 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1457 * Update the record of the current time in a context.
1459 static void update_context_time(struct perf_event_context *ctx)
1461 u64 now = perf_clock();
1463 ctx->time += now - ctx->timestamp;
1464 ctx->timestamp = now;
1467 static u64 perf_event_time(struct perf_event *event)
1469 struct perf_event_context *ctx = event->ctx;
1471 if (is_cgroup_event(event))
1472 return perf_cgroup_event_time(event);
1474 return ctx ? ctx->time : 0;
1477 static enum event_type_t get_event_type(struct perf_event *event)
1479 struct perf_event_context *ctx = event->ctx;
1480 enum event_type_t event_type;
1482 lockdep_assert_held(&ctx->lock);
1485 * It's 'group type', really, because if our group leader is
1486 * pinned, so are we.
1488 if (event->group_leader != event)
1489 event = event->group_leader;
1491 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1493 event_type |= EVENT_CPU;
1499 * Helper function to initialize event group nodes.
1501 static void init_event_group(struct perf_event *event)
1503 RB_CLEAR_NODE(&event->group_node);
1504 event->group_index = 0;
1508 * Extract pinned or flexible groups from the context
1509 * based on event attrs bits.
1511 static struct perf_event_groups *
1512 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1514 if (event->attr.pinned)
1515 return &ctx->pinned_groups;
1517 return &ctx->flexible_groups;
1521 * Helper function to initializes perf_event_group trees.
1523 static void perf_event_groups_init(struct perf_event_groups *groups)
1525 groups->tree = RB_ROOT;
1530 * Compare function for event groups;
1532 * Implements complex key that first sorts by CPU and then by virtual index
1533 * which provides ordering when rotating groups for the same CPU.
1536 perf_event_groups_less(struct perf_event *left, struct perf_event *right)
1538 if (left->cpu < right->cpu)
1540 if (left->cpu > right->cpu)
1543 if (left->group_index < right->group_index)
1545 if (left->group_index > right->group_index)
1552 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1553 * key (see perf_event_groups_less). This places it last inside the CPU
1557 perf_event_groups_insert(struct perf_event_groups *groups,
1558 struct perf_event *event)
1560 struct perf_event *node_event;
1561 struct rb_node *parent;
1562 struct rb_node **node;
1564 event->group_index = ++groups->index;
1566 node = &groups->tree.rb_node;
1571 node_event = container_of(*node, struct perf_event, group_node);
1573 if (perf_event_groups_less(event, node_event))
1574 node = &parent->rb_left;
1576 node = &parent->rb_right;
1579 rb_link_node(&event->group_node, parent, node);
1580 rb_insert_color(&event->group_node, &groups->tree);
1584 * Helper function to insert event into the pinned or flexible groups.
1587 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1589 struct perf_event_groups *groups;
1591 groups = get_event_groups(event, ctx);
1592 perf_event_groups_insert(groups, event);
1596 * Delete a group from a tree.
1599 perf_event_groups_delete(struct perf_event_groups *groups,
1600 struct perf_event *event)
1602 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1603 RB_EMPTY_ROOT(&groups->tree));
1605 rb_erase(&event->group_node, &groups->tree);
1606 init_event_group(event);
1610 * Helper function to delete event from its groups.
1613 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1615 struct perf_event_groups *groups;
1617 groups = get_event_groups(event, ctx);
1618 perf_event_groups_delete(groups, event);
1622 * Get the leftmost event in the @cpu subtree.
1624 static struct perf_event *
1625 perf_event_groups_first(struct perf_event_groups *groups, int cpu)
1627 struct perf_event *node_event = NULL, *match = NULL;
1628 struct rb_node *node = groups->tree.rb_node;
1631 node_event = container_of(node, struct perf_event, group_node);
1633 if (cpu < node_event->cpu) {
1634 node = node->rb_left;
1635 } else if (cpu > node_event->cpu) {
1636 node = node->rb_right;
1639 node = node->rb_left;
1647 * Like rb_entry_next_safe() for the @cpu subtree.
1649 static struct perf_event *
1650 perf_event_groups_next(struct perf_event *event)
1652 struct perf_event *next;
1654 next = rb_entry_safe(rb_next(&event->group_node), typeof(*event), group_node);
1655 if (next && next->cpu == event->cpu)
1662 * Iterate through the whole groups tree.
1664 #define perf_event_groups_for_each(event, groups) \
1665 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1666 typeof(*event), group_node); event; \
1667 event = rb_entry_safe(rb_next(&event->group_node), \
1668 typeof(*event), group_node))
1671 * Add an event from the lists for its context.
1672 * Must be called with ctx->mutex and ctx->lock held.
1675 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1677 lockdep_assert_held(&ctx->lock);
1679 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1680 event->attach_state |= PERF_ATTACH_CONTEXT;
1682 event->tstamp = perf_event_time(event);
1685 * If we're a stand alone event or group leader, we go to the context
1686 * list, group events are kept attached to the group so that
1687 * perf_group_detach can, at all times, locate all siblings.
1689 if (event->group_leader == event) {
1690 event->group_caps = event->event_caps;
1691 add_event_to_groups(event, ctx);
1694 list_update_cgroup_event(event, ctx, true);
1696 list_add_rcu(&event->event_entry, &ctx->event_list);
1698 if (event->attr.inherit_stat)
1705 * Initialize event state based on the perf_event_attr::disabled.
1707 static inline void perf_event__state_init(struct perf_event *event)
1709 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1710 PERF_EVENT_STATE_INACTIVE;
1713 static int __perf_event_read_size(u64 read_format, int nr_siblings)
1715 int entry = sizeof(u64); /* value */
1719 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1720 size += sizeof(u64);
1722 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1723 size += sizeof(u64);
1725 if (read_format & PERF_FORMAT_ID)
1726 entry += sizeof(u64);
1728 if (read_format & PERF_FORMAT_LOST)
1729 entry += sizeof(u64);
1731 if (read_format & PERF_FORMAT_GROUP) {
1733 size += sizeof(u64);
1737 * Since perf_event_validate_size() limits this to 16k and inhibits
1738 * adding more siblings, this will never overflow.
1740 return size + nr * entry;
1743 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1745 struct perf_sample_data *data;
1748 if (sample_type & PERF_SAMPLE_IP)
1749 size += sizeof(data->ip);
1751 if (sample_type & PERF_SAMPLE_ADDR)
1752 size += sizeof(data->addr);
1754 if (sample_type & PERF_SAMPLE_PERIOD)
1755 size += sizeof(data->period);
1757 if (sample_type & PERF_SAMPLE_WEIGHT)
1758 size += sizeof(data->weight);
1760 if (sample_type & PERF_SAMPLE_READ)
1761 size += event->read_size;
1763 if (sample_type & PERF_SAMPLE_DATA_SRC)
1764 size += sizeof(data->data_src.val);
1766 if (sample_type & PERF_SAMPLE_TRANSACTION)
1767 size += sizeof(data->txn);
1769 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1770 size += sizeof(data->phys_addr);
1772 event->header_size = size;
1776 * Called at perf_event creation and when events are attached/detached from a
1779 static void perf_event__header_size(struct perf_event *event)
1782 __perf_event_read_size(event->attr.read_format,
1783 event->group_leader->nr_siblings);
1784 __perf_event_header_size(event, event->attr.sample_type);
1787 static void perf_event__id_header_size(struct perf_event *event)
1789 struct perf_sample_data *data;
1790 u64 sample_type = event->attr.sample_type;
1793 if (sample_type & PERF_SAMPLE_TID)
1794 size += sizeof(data->tid_entry);
1796 if (sample_type & PERF_SAMPLE_TIME)
1797 size += sizeof(data->time);
1799 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1800 size += sizeof(data->id);
1802 if (sample_type & PERF_SAMPLE_ID)
1803 size += sizeof(data->id);
1805 if (sample_type & PERF_SAMPLE_STREAM_ID)
1806 size += sizeof(data->stream_id);
1808 if (sample_type & PERF_SAMPLE_CPU)
1809 size += sizeof(data->cpu_entry);
1811 event->id_header_size = size;
1815 * Check that adding an event to the group does not result in anybody
1816 * overflowing the 64k event limit imposed by the output buffer.
1818 * Specifically, check that the read_size for the event does not exceed 16k,
1819 * read_size being the one term that grows with groups size. Since read_size
1820 * depends on per-event read_format, also (re)check the existing events.
1822 * This leaves 48k for the constant size fields and things like callchains,
1823 * branch stacks and register sets.
1825 static bool perf_event_validate_size(struct perf_event *event)
1827 struct perf_event *sibling, *group_leader = event->group_leader;
1829 if (__perf_event_read_size(event->attr.read_format,
1830 group_leader->nr_siblings + 1) > 16*1024)
1833 if (__perf_event_read_size(group_leader->attr.read_format,
1834 group_leader->nr_siblings + 1) > 16*1024)
1838 * When creating a new group leader, group_leader->ctx is initialized
1839 * after the size has been validated, but we cannot safely use
1840 * for_each_sibling_event() until group_leader->ctx is set. A new group
1841 * leader cannot have any siblings yet, so we can safely skip checking
1842 * the non-existent siblings.
1844 if (event == group_leader)
1847 for_each_sibling_event(sibling, group_leader) {
1848 if (__perf_event_read_size(sibling->attr.read_format,
1849 group_leader->nr_siblings + 1) > 16*1024)
1856 static void perf_group_attach(struct perf_event *event)
1858 struct perf_event *group_leader = event->group_leader, *pos;
1860 lockdep_assert_held(&event->ctx->lock);
1863 * We can have double attach due to group movement in perf_event_open.
1865 if (event->attach_state & PERF_ATTACH_GROUP)
1868 event->attach_state |= PERF_ATTACH_GROUP;
1870 if (group_leader == event)
1873 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1875 group_leader->group_caps &= event->event_caps;
1877 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1878 group_leader->nr_siblings++;
1879 group_leader->group_generation++;
1881 perf_event__header_size(group_leader);
1883 for_each_sibling_event(pos, group_leader)
1884 perf_event__header_size(pos);
1888 * Remove an event from the lists for its context.
1889 * Must be called with ctx->mutex and ctx->lock held.
1892 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1894 WARN_ON_ONCE(event->ctx != ctx);
1895 lockdep_assert_held(&ctx->lock);
1898 * We can have double detach due to exit/hot-unplug + close.
1900 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1903 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1905 list_update_cgroup_event(event, ctx, false);
1908 if (event->attr.inherit_stat)
1911 list_del_rcu(&event->event_entry);
1913 if (event->group_leader == event)
1914 del_event_from_groups(event, ctx);
1917 * If event was in error state, then keep it
1918 * that way, otherwise bogus counts will be
1919 * returned on read(). The only way to get out
1920 * of error state is by explicit re-enabling
1923 if (event->state > PERF_EVENT_STATE_OFF)
1924 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1929 static void perf_group_detach(struct perf_event *event)
1931 struct perf_event *sibling, *tmp;
1932 struct perf_event_context *ctx = event->ctx;
1934 lockdep_assert_held(&ctx->lock);
1937 * We can have double detach due to exit/hot-unplug + close.
1939 if (!(event->attach_state & PERF_ATTACH_GROUP))
1942 event->attach_state &= ~PERF_ATTACH_GROUP;
1945 * If this is a sibling, remove it from its group.
1947 if (event->group_leader != event) {
1948 list_del_init(&event->sibling_list);
1949 event->group_leader->nr_siblings--;
1950 event->group_leader->group_generation++;
1955 * If this was a group event with sibling events then
1956 * upgrade the siblings to singleton events by adding them
1957 * to whatever list we are on.
1959 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
1961 sibling->group_leader = sibling;
1962 list_del_init(&sibling->sibling_list);
1964 /* Inherit group flags from the previous leader */
1965 sibling->group_caps = event->group_caps;
1967 if (!RB_EMPTY_NODE(&event->group_node)) {
1968 add_event_to_groups(sibling, event->ctx);
1970 if (sibling->state == PERF_EVENT_STATE_ACTIVE) {
1971 struct list_head *list = sibling->attr.pinned ?
1972 &ctx->pinned_active : &ctx->flexible_active;
1974 list_add_tail(&sibling->active_list, list);
1978 WARN_ON_ONCE(sibling->ctx != event->ctx);
1982 perf_event__header_size(event->group_leader);
1984 for_each_sibling_event(tmp, event->group_leader)
1985 perf_event__header_size(tmp);
1988 static bool is_orphaned_event(struct perf_event *event)
1990 return event->state == PERF_EVENT_STATE_DEAD;
1993 static inline int __pmu_filter_match(struct perf_event *event)
1995 struct pmu *pmu = event->pmu;
1996 return pmu->filter_match ? pmu->filter_match(event) : 1;
2000 * Check whether we should attempt to schedule an event group based on
2001 * PMU-specific filtering. An event group can consist of HW and SW events,
2002 * potentially with a SW leader, so we must check all the filters, to
2003 * determine whether a group is schedulable:
2005 static inline int pmu_filter_match(struct perf_event *event)
2007 struct perf_event *sibling;
2009 if (!__pmu_filter_match(event))
2012 for_each_sibling_event(sibling, event) {
2013 if (!__pmu_filter_match(sibling))
2021 event_filter_match(struct perf_event *event)
2023 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2024 perf_cgroup_match(event) && pmu_filter_match(event);
2028 event_sched_out(struct perf_event *event,
2029 struct perf_cpu_context *cpuctx,
2030 struct perf_event_context *ctx)
2032 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2034 WARN_ON_ONCE(event->ctx != ctx);
2035 lockdep_assert_held(&ctx->lock);
2037 if (event->state != PERF_EVENT_STATE_ACTIVE)
2041 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2042 * we can schedule events _OUT_ individually through things like
2043 * __perf_remove_from_context().
2045 list_del_init(&event->active_list);
2047 perf_pmu_disable(event->pmu);
2049 event->pmu->del(event, 0);
2052 if (READ_ONCE(event->pending_disable) >= 0) {
2053 WRITE_ONCE(event->pending_disable, -1);
2054 state = PERF_EVENT_STATE_OFF;
2056 perf_event_set_state(event, state);
2058 if (!is_software_event(event))
2059 cpuctx->active_oncpu--;
2060 if (!--ctx->nr_active)
2061 perf_event_ctx_deactivate(ctx);
2062 if (event->attr.freq && event->attr.sample_freq)
2064 if (event->attr.exclusive || !cpuctx->active_oncpu)
2065 cpuctx->exclusive = 0;
2067 perf_pmu_enable(event->pmu);
2071 group_sched_out(struct perf_event *group_event,
2072 struct perf_cpu_context *cpuctx,
2073 struct perf_event_context *ctx)
2075 struct perf_event *event;
2077 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2080 perf_pmu_disable(ctx->pmu);
2082 event_sched_out(group_event, cpuctx, ctx);
2085 * Schedule out siblings (if any):
2087 for_each_sibling_event(event, group_event)
2088 event_sched_out(event, cpuctx, ctx);
2090 perf_pmu_enable(ctx->pmu);
2092 if (group_event->attr.exclusive)
2093 cpuctx->exclusive = 0;
2096 #define DETACH_GROUP 0x01UL
2099 * Cross CPU call to remove a performance event
2101 * We disable the event on the hardware level first. After that we
2102 * remove it from the context list.
2105 __perf_remove_from_context(struct perf_event *event,
2106 struct perf_cpu_context *cpuctx,
2107 struct perf_event_context *ctx,
2110 unsigned long flags = (unsigned long)info;
2112 if (ctx->is_active & EVENT_TIME) {
2113 update_context_time(ctx);
2114 update_cgrp_time_from_cpuctx(cpuctx);
2117 event_sched_out(event, cpuctx, ctx);
2118 if (flags & DETACH_GROUP)
2119 perf_group_detach(event);
2120 list_del_event(event, ctx);
2122 if (!ctx->nr_events && ctx->is_active) {
2124 ctx->rotate_necessary = 0;
2126 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2127 cpuctx->task_ctx = NULL;
2133 * Remove the event from a task's (or a CPU's) list of events.
2135 * If event->ctx is a cloned context, callers must make sure that
2136 * every task struct that event->ctx->task could possibly point to
2137 * remains valid. This is OK when called from perf_release since
2138 * that only calls us on the top-level context, which can't be a clone.
2139 * When called from perf_event_exit_task, it's OK because the
2140 * context has been detached from its task.
2142 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2144 struct perf_event_context *ctx = event->ctx;
2146 lockdep_assert_held(&ctx->mutex);
2148 event_function_call(event, __perf_remove_from_context, (void *)flags);
2151 * The above event_function_call() can NO-OP when it hits
2152 * TASK_TOMBSTONE. In that case we must already have been detached
2153 * from the context (by perf_event_exit_event()) but the grouping
2154 * might still be in-tact.
2156 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
2157 if ((flags & DETACH_GROUP) &&
2158 (event->attach_state & PERF_ATTACH_GROUP)) {
2160 * Since in that case we cannot possibly be scheduled, simply
2163 raw_spin_lock_irq(&ctx->lock);
2164 perf_group_detach(event);
2165 raw_spin_unlock_irq(&ctx->lock);
2170 * Cross CPU call to disable a performance event
2172 static void __perf_event_disable(struct perf_event *event,
2173 struct perf_cpu_context *cpuctx,
2174 struct perf_event_context *ctx,
2177 if (event->state < PERF_EVENT_STATE_INACTIVE)
2180 if (ctx->is_active & EVENT_TIME) {
2181 update_context_time(ctx);
2182 update_cgrp_time_from_event(event);
2185 if (event == event->group_leader)
2186 group_sched_out(event, cpuctx, ctx);
2188 event_sched_out(event, cpuctx, ctx);
2190 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2196 * If event->ctx is a cloned context, callers must make sure that
2197 * every task struct that event->ctx->task could possibly point to
2198 * remains valid. This condition is satisifed when called through
2199 * perf_event_for_each_child or perf_event_for_each because they
2200 * hold the top-level event's child_mutex, so any descendant that
2201 * goes to exit will block in perf_event_exit_event().
2203 * When called from perf_pending_event it's OK because event->ctx
2204 * is the current context on this CPU and preemption is disabled,
2205 * hence we can't get into perf_event_task_sched_out for this context.
2207 static void _perf_event_disable(struct perf_event *event)
2209 struct perf_event_context *ctx = event->ctx;
2211 raw_spin_lock_irq(&ctx->lock);
2212 if (event->state <= PERF_EVENT_STATE_OFF) {
2213 raw_spin_unlock_irq(&ctx->lock);
2216 raw_spin_unlock_irq(&ctx->lock);
2218 event_function_call(event, __perf_event_disable, NULL);
2221 void perf_event_disable_local(struct perf_event *event)
2223 event_function_local(event, __perf_event_disable, NULL);
2227 * Strictly speaking kernel users cannot create groups and therefore this
2228 * interface does not need the perf_event_ctx_lock() magic.
2230 void perf_event_disable(struct perf_event *event)
2232 struct perf_event_context *ctx;
2234 ctx = perf_event_ctx_lock(event);
2235 _perf_event_disable(event);
2236 perf_event_ctx_unlock(event, ctx);
2238 EXPORT_SYMBOL_GPL(perf_event_disable);
2240 void perf_event_disable_inatomic(struct perf_event *event)
2242 WRITE_ONCE(event->pending_disable, smp_processor_id());
2243 /* can fail, see perf_pending_event_disable() */
2244 irq_work_queue(&event->pending);
2247 static void perf_set_shadow_time(struct perf_event *event,
2248 struct perf_event_context *ctx)
2251 * use the correct time source for the time snapshot
2253 * We could get by without this by leveraging the
2254 * fact that to get to this function, the caller
2255 * has most likely already called update_context_time()
2256 * and update_cgrp_time_xx() and thus both timestamp
2257 * are identical (or very close). Given that tstamp is,
2258 * already adjusted for cgroup, we could say that:
2259 * tstamp - ctx->timestamp
2261 * tstamp - cgrp->timestamp.
2263 * Then, in perf_output_read(), the calculation would
2264 * work with no changes because:
2265 * - event is guaranteed scheduled in
2266 * - no scheduled out in between
2267 * - thus the timestamp would be the same
2269 * But this is a bit hairy.
2271 * So instead, we have an explicit cgroup call to remain
2272 * within the time time source all along. We believe it
2273 * is cleaner and simpler to understand.
2275 if (is_cgroup_event(event))
2276 perf_cgroup_set_shadow_time(event, event->tstamp);
2278 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2281 #define MAX_INTERRUPTS (~0ULL)
2283 static void perf_log_throttle(struct perf_event *event, int enable);
2284 static void perf_log_itrace_start(struct perf_event *event);
2287 event_sched_in(struct perf_event *event,
2288 struct perf_cpu_context *cpuctx,
2289 struct perf_event_context *ctx)
2293 lockdep_assert_held(&ctx->lock);
2295 if (event->state <= PERF_EVENT_STATE_OFF)
2298 WRITE_ONCE(event->oncpu, smp_processor_id());
2300 * Order event::oncpu write to happen before the ACTIVE state is
2301 * visible. This allows perf_event_{stop,read}() to observe the correct
2302 * ->oncpu if it sees ACTIVE.
2305 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2308 * Unthrottle events, since we scheduled we might have missed several
2309 * ticks already, also for a heavily scheduling task there is little
2310 * guarantee it'll get a tick in a timely manner.
2312 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2313 perf_log_throttle(event, 1);
2314 event->hw.interrupts = 0;
2317 perf_pmu_disable(event->pmu);
2319 perf_set_shadow_time(event, ctx);
2321 perf_log_itrace_start(event);
2323 if (event->pmu->add(event, PERF_EF_START)) {
2324 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2330 if (!is_software_event(event))
2331 cpuctx->active_oncpu++;
2332 if (!ctx->nr_active++)
2333 perf_event_ctx_activate(ctx);
2334 if (event->attr.freq && event->attr.sample_freq)
2337 if (event->attr.exclusive)
2338 cpuctx->exclusive = 1;
2341 perf_pmu_enable(event->pmu);
2347 group_sched_in(struct perf_event *group_event,
2348 struct perf_cpu_context *cpuctx,
2349 struct perf_event_context *ctx)
2351 struct perf_event *event, *partial_group = NULL;
2352 struct pmu *pmu = ctx->pmu;
2354 if (group_event->state == PERF_EVENT_STATE_OFF)
2357 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2359 if (event_sched_in(group_event, cpuctx, ctx)) {
2360 pmu->cancel_txn(pmu);
2361 perf_mux_hrtimer_restart(cpuctx);
2366 * Schedule in siblings as one group (if any):
2368 for_each_sibling_event(event, group_event) {
2369 if (event_sched_in(event, cpuctx, ctx)) {
2370 partial_group = event;
2375 if (!pmu->commit_txn(pmu))
2380 * Groups can be scheduled in as one unit only, so undo any
2381 * partial group before returning:
2382 * The events up to the failed event are scheduled out normally.
2384 for_each_sibling_event(event, group_event) {
2385 if (event == partial_group)
2388 event_sched_out(event, cpuctx, ctx);
2390 event_sched_out(group_event, cpuctx, ctx);
2392 pmu->cancel_txn(pmu);
2394 perf_mux_hrtimer_restart(cpuctx);
2400 * Work out whether we can put this event group on the CPU now.
2402 static int group_can_go_on(struct perf_event *event,
2403 struct perf_cpu_context *cpuctx,
2407 * Groups consisting entirely of software events can always go on.
2409 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2412 * If an exclusive group is already on, no other hardware
2415 if (cpuctx->exclusive)
2418 * If this group is exclusive and there are already
2419 * events on the CPU, it can't go on.
2421 if (event->attr.exclusive && cpuctx->active_oncpu)
2424 * Otherwise, try to add it if all previous groups were able
2430 static void add_event_to_ctx(struct perf_event *event,
2431 struct perf_event_context *ctx)
2433 list_add_event(event, ctx);
2434 perf_group_attach(event);
2437 static void ctx_sched_out(struct perf_event_context *ctx,
2438 struct perf_cpu_context *cpuctx,
2439 enum event_type_t event_type);
2441 ctx_sched_in(struct perf_event_context *ctx,
2442 struct perf_cpu_context *cpuctx,
2443 enum event_type_t event_type,
2444 struct task_struct *task);
2446 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2447 struct perf_event_context *ctx,
2448 enum event_type_t event_type)
2450 if (!cpuctx->task_ctx)
2453 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2456 ctx_sched_out(ctx, cpuctx, event_type);
2459 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2460 struct perf_event_context *ctx,
2461 struct task_struct *task)
2463 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2465 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2466 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2468 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2472 * We want to maintain the following priority of scheduling:
2473 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2474 * - task pinned (EVENT_PINNED)
2475 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2476 * - task flexible (EVENT_FLEXIBLE).
2478 * In order to avoid unscheduling and scheduling back in everything every
2479 * time an event is added, only do it for the groups of equal priority and
2482 * This can be called after a batch operation on task events, in which case
2483 * event_type is a bit mask of the types of events involved. For CPU events,
2484 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2486 static void ctx_resched(struct perf_cpu_context *cpuctx,
2487 struct perf_event_context *task_ctx,
2488 enum event_type_t event_type)
2490 enum event_type_t ctx_event_type;
2491 bool cpu_event = !!(event_type & EVENT_CPU);
2494 * If pinned groups are involved, flexible groups also need to be
2497 if (event_type & EVENT_PINNED)
2498 event_type |= EVENT_FLEXIBLE;
2500 ctx_event_type = event_type & EVENT_ALL;
2502 perf_pmu_disable(cpuctx->ctx.pmu);
2504 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2507 * Decide which cpu ctx groups to schedule out based on the types
2508 * of events that caused rescheduling:
2509 * - EVENT_CPU: schedule out corresponding groups;
2510 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2511 * - otherwise, do nothing more.
2514 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2515 else if (ctx_event_type & EVENT_PINNED)
2516 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2518 perf_event_sched_in(cpuctx, task_ctx, current);
2519 perf_pmu_enable(cpuctx->ctx.pmu);
2523 * Cross CPU call to install and enable a performance event
2525 * Very similar to remote_function() + event_function() but cannot assume that
2526 * things like ctx->is_active and cpuctx->task_ctx are set.
2528 static int __perf_install_in_context(void *info)
2530 struct perf_event *event = info;
2531 struct perf_event_context *ctx = event->ctx;
2532 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2533 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2534 bool reprogram = true;
2537 raw_spin_lock(&cpuctx->ctx.lock);
2539 raw_spin_lock(&ctx->lock);
2542 reprogram = (ctx->task == current);
2545 * If the task is running, it must be running on this CPU,
2546 * otherwise we cannot reprogram things.
2548 * If its not running, we don't care, ctx->lock will
2549 * serialize against it becoming runnable.
2551 if (task_curr(ctx->task) && !reprogram) {
2556 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2557 } else if (task_ctx) {
2558 raw_spin_lock(&task_ctx->lock);
2561 #ifdef CONFIG_CGROUP_PERF
2562 if (is_cgroup_event(event)) {
2564 * If the current cgroup doesn't match the event's
2565 * cgroup, we should not try to schedule it.
2567 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2568 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2569 event->cgrp->css.cgroup);
2574 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2575 add_event_to_ctx(event, ctx);
2576 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2578 add_event_to_ctx(event, ctx);
2582 perf_ctx_unlock(cpuctx, task_ctx);
2587 static bool exclusive_event_installable(struct perf_event *event,
2588 struct perf_event_context *ctx);
2591 * Attach a performance event to a context.
2593 * Very similar to event_function_call, see comment there.
2596 perf_install_in_context(struct perf_event_context *ctx,
2597 struct perf_event *event,
2600 struct task_struct *task = READ_ONCE(ctx->task);
2602 lockdep_assert_held(&ctx->mutex);
2604 WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2606 if (event->cpu != -1)
2610 * Ensures that if we can observe event->ctx, both the event and ctx
2611 * will be 'complete'. See perf_iterate_sb_cpu().
2613 smp_store_release(&event->ctx, ctx);
2616 cpu_function_call(cpu, __perf_install_in_context, event);
2621 * Should not happen, we validate the ctx is still alive before calling.
2623 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2627 * Installing events is tricky because we cannot rely on ctx->is_active
2628 * to be set in case this is the nr_events 0 -> 1 transition.
2630 * Instead we use task_curr(), which tells us if the task is running.
2631 * However, since we use task_curr() outside of rq::lock, we can race
2632 * against the actual state. This means the result can be wrong.
2634 * If we get a false positive, we retry, this is harmless.
2636 * If we get a false negative, things are complicated. If we are after
2637 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2638 * value must be correct. If we're before, it doesn't matter since
2639 * perf_event_context_sched_in() will program the counter.
2641 * However, this hinges on the remote context switch having observed
2642 * our task->perf_event_ctxp[] store, such that it will in fact take
2643 * ctx::lock in perf_event_context_sched_in().
2645 * We do this by task_function_call(), if the IPI fails to hit the task
2646 * we know any future context switch of task must see the
2647 * perf_event_ctpx[] store.
2651 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2652 * task_cpu() load, such that if the IPI then does not find the task
2653 * running, a future context switch of that task must observe the
2658 if (!task_function_call(task, __perf_install_in_context, event))
2661 raw_spin_lock_irq(&ctx->lock);
2663 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2665 * Cannot happen because we already checked above (which also
2666 * cannot happen), and we hold ctx->mutex, which serializes us
2667 * against perf_event_exit_task_context().
2669 raw_spin_unlock_irq(&ctx->lock);
2673 * If the task is not running, ctx->lock will avoid it becoming so,
2674 * thus we can safely install the event.
2676 if (task_curr(task)) {
2677 raw_spin_unlock_irq(&ctx->lock);
2680 add_event_to_ctx(event, ctx);
2681 raw_spin_unlock_irq(&ctx->lock);
2685 * Cross CPU call to enable a performance event
2687 static void __perf_event_enable(struct perf_event *event,
2688 struct perf_cpu_context *cpuctx,
2689 struct perf_event_context *ctx,
2692 struct perf_event *leader = event->group_leader;
2693 struct perf_event_context *task_ctx;
2695 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2696 event->state <= PERF_EVENT_STATE_ERROR)
2700 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2702 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2704 if (!ctx->is_active)
2707 if (!event_filter_match(event)) {
2708 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2713 * If the event is in a group and isn't the group leader,
2714 * then don't put it on unless the group is on.
2716 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2717 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2721 task_ctx = cpuctx->task_ctx;
2723 WARN_ON_ONCE(task_ctx != ctx);
2725 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2731 * If event->ctx is a cloned context, callers must make sure that
2732 * every task struct that event->ctx->task could possibly point to
2733 * remains valid. This condition is satisfied when called through
2734 * perf_event_for_each_child or perf_event_for_each as described
2735 * for perf_event_disable.
2737 static void _perf_event_enable(struct perf_event *event)
2739 struct perf_event_context *ctx = event->ctx;
2741 raw_spin_lock_irq(&ctx->lock);
2742 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2743 event->state < PERF_EVENT_STATE_ERROR) {
2744 raw_spin_unlock_irq(&ctx->lock);
2749 * If the event is in error state, clear that first.
2751 * That way, if we see the event in error state below, we know that it
2752 * has gone back into error state, as distinct from the task having
2753 * been scheduled away before the cross-call arrived.
2755 if (event->state == PERF_EVENT_STATE_ERROR)
2756 event->state = PERF_EVENT_STATE_OFF;
2757 raw_spin_unlock_irq(&ctx->lock);
2759 event_function_call(event, __perf_event_enable, NULL);
2763 * See perf_event_disable();
2765 void perf_event_enable(struct perf_event *event)
2767 struct perf_event_context *ctx;
2769 ctx = perf_event_ctx_lock(event);
2770 _perf_event_enable(event);
2771 perf_event_ctx_unlock(event, ctx);
2773 EXPORT_SYMBOL_GPL(perf_event_enable);
2775 struct stop_event_data {
2776 struct perf_event *event;
2777 unsigned int restart;
2780 static int __perf_event_stop(void *info)
2782 struct stop_event_data *sd = info;
2783 struct perf_event *event = sd->event;
2785 /* if it's already INACTIVE, do nothing */
2786 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2789 /* matches smp_wmb() in event_sched_in() */
2793 * There is a window with interrupts enabled before we get here,
2794 * so we need to check again lest we try to stop another CPU's event.
2796 if (READ_ONCE(event->oncpu) != smp_processor_id())
2799 event->pmu->stop(event, PERF_EF_UPDATE);
2802 * May race with the actual stop (through perf_pmu_output_stop()),
2803 * but it is only used for events with AUX ring buffer, and such
2804 * events will refuse to restart because of rb::aux_mmap_count==0,
2805 * see comments in perf_aux_output_begin().
2807 * Since this is happening on an event-local CPU, no trace is lost
2811 event->pmu->start(event, 0);
2816 static int perf_event_stop(struct perf_event *event, int restart)
2818 struct stop_event_data sd = {
2825 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2828 /* matches smp_wmb() in event_sched_in() */
2832 * We only want to restart ACTIVE events, so if the event goes
2833 * inactive here (event->oncpu==-1), there's nothing more to do;
2834 * fall through with ret==-ENXIO.
2836 ret = cpu_function_call(READ_ONCE(event->oncpu),
2837 __perf_event_stop, &sd);
2838 } while (ret == -EAGAIN);
2844 * In order to contain the amount of racy and tricky in the address filter
2845 * configuration management, it is a two part process:
2847 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2848 * we update the addresses of corresponding vmas in
2849 * event::addr_filter_ranges array and bump the event::addr_filters_gen;
2850 * (p2) when an event is scheduled in (pmu::add), it calls
2851 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2852 * if the generation has changed since the previous call.
2854 * If (p1) happens while the event is active, we restart it to force (p2).
2856 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2857 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2859 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2860 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2862 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2865 void perf_event_addr_filters_sync(struct perf_event *event)
2867 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2869 if (!has_addr_filter(event))
2872 raw_spin_lock(&ifh->lock);
2873 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2874 event->pmu->addr_filters_sync(event);
2875 event->hw.addr_filters_gen = event->addr_filters_gen;
2877 raw_spin_unlock(&ifh->lock);
2879 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2881 static int _perf_event_refresh(struct perf_event *event, int refresh)
2884 * not supported on inherited events
2886 if (event->attr.inherit || !is_sampling_event(event))
2889 atomic_add(refresh, &event->event_limit);
2890 _perf_event_enable(event);
2896 * See perf_event_disable()
2898 int perf_event_refresh(struct perf_event *event, int refresh)
2900 struct perf_event_context *ctx;
2903 ctx = perf_event_ctx_lock(event);
2904 ret = _perf_event_refresh(event, refresh);
2905 perf_event_ctx_unlock(event, ctx);
2909 EXPORT_SYMBOL_GPL(perf_event_refresh);
2911 static int perf_event_modify_breakpoint(struct perf_event *bp,
2912 struct perf_event_attr *attr)
2916 _perf_event_disable(bp);
2918 err = modify_user_hw_breakpoint_check(bp, attr, true);
2920 if (!bp->attr.disabled)
2921 _perf_event_enable(bp);
2926 static int perf_event_modify_attr(struct perf_event *event,
2927 struct perf_event_attr *attr)
2929 if (event->attr.type != attr->type)
2932 switch (event->attr.type) {
2933 case PERF_TYPE_BREAKPOINT:
2934 return perf_event_modify_breakpoint(event, attr);
2936 /* Place holder for future additions. */
2941 static void ctx_sched_out(struct perf_event_context *ctx,
2942 struct perf_cpu_context *cpuctx,
2943 enum event_type_t event_type)
2945 struct perf_event *event, *tmp;
2946 int is_active = ctx->is_active;
2948 lockdep_assert_held(&ctx->lock);
2950 if (likely(!ctx->nr_events)) {
2952 * See __perf_remove_from_context().
2954 WARN_ON_ONCE(ctx->is_active);
2956 WARN_ON_ONCE(cpuctx->task_ctx);
2960 ctx->is_active &= ~event_type;
2961 if (!(ctx->is_active & EVENT_ALL))
2965 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2966 if (!ctx->is_active)
2967 cpuctx->task_ctx = NULL;
2971 * Always update time if it was set; not only when it changes.
2972 * Otherwise we can 'forget' to update time for any but the last
2973 * context we sched out. For example:
2975 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2976 * ctx_sched_out(.event_type = EVENT_PINNED)
2978 * would only update time for the pinned events.
2980 if (is_active & EVENT_TIME) {
2981 /* update (and stop) ctx time */
2982 update_context_time(ctx);
2983 update_cgrp_time_from_cpuctx(cpuctx);
2986 is_active ^= ctx->is_active; /* changed bits */
2988 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2991 perf_pmu_disable(ctx->pmu);
2992 if (is_active & EVENT_PINNED) {
2993 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
2994 group_sched_out(event, cpuctx, ctx);
2997 if (is_active & EVENT_FLEXIBLE) {
2998 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
2999 group_sched_out(event, cpuctx, ctx);
3002 * Since we cleared EVENT_FLEXIBLE, also clear
3003 * rotate_necessary, is will be reset by
3004 * ctx_flexible_sched_in() when needed.
3006 ctx->rotate_necessary = 0;
3008 perf_pmu_enable(ctx->pmu);
3012 * Test whether two contexts are equivalent, i.e. whether they have both been
3013 * cloned from the same version of the same context.
3015 * Equivalence is measured using a generation number in the context that is
3016 * incremented on each modification to it; see unclone_ctx(), list_add_event()
3017 * and list_del_event().
3019 static int context_equiv(struct perf_event_context *ctx1,
3020 struct perf_event_context *ctx2)
3022 lockdep_assert_held(&ctx1->lock);
3023 lockdep_assert_held(&ctx2->lock);
3025 /* Pinning disables the swap optimization */
3026 if (ctx1->pin_count || ctx2->pin_count)
3029 /* If ctx1 is the parent of ctx2 */
3030 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3033 /* If ctx2 is the parent of ctx1 */
3034 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3038 * If ctx1 and ctx2 have the same parent; we flatten the parent
3039 * hierarchy, see perf_event_init_context().
3041 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3042 ctx1->parent_gen == ctx2->parent_gen)
3049 static void __perf_event_sync_stat(struct perf_event *event,
3050 struct perf_event *next_event)
3054 if (!event->attr.inherit_stat)
3058 * Update the event value, we cannot use perf_event_read()
3059 * because we're in the middle of a context switch and have IRQs
3060 * disabled, which upsets smp_call_function_single(), however
3061 * we know the event must be on the current CPU, therefore we
3062 * don't need to use it.
3064 if (event->state == PERF_EVENT_STATE_ACTIVE)
3065 event->pmu->read(event);
3067 perf_event_update_time(event);
3070 * In order to keep per-task stats reliable we need to flip the event
3071 * values when we flip the contexts.
3073 value = local64_read(&next_event->count);
3074 value = local64_xchg(&event->count, value);
3075 local64_set(&next_event->count, value);
3077 swap(event->total_time_enabled, next_event->total_time_enabled);
3078 swap(event->total_time_running, next_event->total_time_running);
3081 * Since we swizzled the values, update the user visible data too.
3083 perf_event_update_userpage(event);
3084 perf_event_update_userpage(next_event);
3087 static void perf_event_sync_stat(struct perf_event_context *ctx,
3088 struct perf_event_context *next_ctx)
3090 struct perf_event *event, *next_event;
3095 update_context_time(ctx);
3097 event = list_first_entry(&ctx->event_list,
3098 struct perf_event, event_entry);
3100 next_event = list_first_entry(&next_ctx->event_list,
3101 struct perf_event, event_entry);
3103 while (&event->event_entry != &ctx->event_list &&
3104 &next_event->event_entry != &next_ctx->event_list) {
3106 __perf_event_sync_stat(event, next_event);
3108 event = list_next_entry(event, event_entry);
3109 next_event = list_next_entry(next_event, event_entry);
3113 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3114 struct task_struct *next)
3116 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3117 struct perf_event_context *next_ctx;
3118 struct perf_event_context *parent, *next_parent;
3119 struct perf_cpu_context *cpuctx;
3125 cpuctx = __get_cpu_context(ctx);
3126 if (!cpuctx->task_ctx)
3130 next_ctx = next->perf_event_ctxp[ctxn];
3134 parent = rcu_dereference(ctx->parent_ctx);
3135 next_parent = rcu_dereference(next_ctx->parent_ctx);
3137 /* If neither context have a parent context; they cannot be clones. */
3138 if (!parent && !next_parent)
3141 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3143 * Looks like the two contexts are clones, so we might be
3144 * able to optimize the context switch. We lock both
3145 * contexts and check that they are clones under the
3146 * lock (including re-checking that neither has been
3147 * uncloned in the meantime). It doesn't matter which
3148 * order we take the locks because no other cpu could
3149 * be trying to lock both of these tasks.
3151 raw_spin_lock(&ctx->lock);
3152 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3153 if (context_equiv(ctx, next_ctx)) {
3154 WRITE_ONCE(ctx->task, next);
3155 WRITE_ONCE(next_ctx->task, task);
3157 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3160 * RCU_INIT_POINTER here is safe because we've not
3161 * modified the ctx and the above modification of
3162 * ctx->task and ctx->task_ctx_data are immaterial
3163 * since those values are always verified under
3164 * ctx->lock which we're now holding.
3166 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3167 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3171 perf_event_sync_stat(ctx, next_ctx);
3173 raw_spin_unlock(&next_ctx->lock);
3174 raw_spin_unlock(&ctx->lock);
3180 raw_spin_lock(&ctx->lock);
3181 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3182 raw_spin_unlock(&ctx->lock);
3186 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3188 void perf_sched_cb_dec(struct pmu *pmu)
3190 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3192 this_cpu_dec(perf_sched_cb_usages);
3194 if (!--cpuctx->sched_cb_usage)
3195 list_del(&cpuctx->sched_cb_entry);
3199 void perf_sched_cb_inc(struct pmu *pmu)
3201 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3203 if (!cpuctx->sched_cb_usage++)
3204 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3206 this_cpu_inc(perf_sched_cb_usages);
3210 * This function provides the context switch callback to the lower code
3211 * layer. It is invoked ONLY when the context switch callback is enabled.
3213 * This callback is relevant even to per-cpu events; for example multi event
3214 * PEBS requires this to provide PID/TID information. This requires we flush
3215 * all queued PEBS records before we context switch to a new task.
3217 static void perf_pmu_sched_task(struct task_struct *prev,
3218 struct task_struct *next,
3221 struct perf_cpu_context *cpuctx;
3227 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3228 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3230 if (WARN_ON_ONCE(!pmu->sched_task))
3233 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3234 perf_pmu_disable(pmu);
3236 pmu->sched_task(cpuctx->task_ctx, sched_in);
3238 perf_pmu_enable(pmu);
3239 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3243 static void perf_event_switch(struct task_struct *task,
3244 struct task_struct *next_prev, bool sched_in);
3246 #define for_each_task_context_nr(ctxn) \
3247 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3250 * Called from scheduler to remove the events of the current task,
3251 * with interrupts disabled.
3253 * We stop each event and update the event value in event->count.
3255 * This does not protect us against NMI, but disable()
3256 * sets the disabled bit in the control field of event _before_
3257 * accessing the event control register. If a NMI hits, then it will
3258 * not restart the event.
3260 void __perf_event_task_sched_out(struct task_struct *task,
3261 struct task_struct *next)
3265 if (__this_cpu_read(perf_sched_cb_usages))
3266 perf_pmu_sched_task(task, next, false);
3268 if (atomic_read(&nr_switch_events))
3269 perf_event_switch(task, next, false);
3271 for_each_task_context_nr(ctxn)
3272 perf_event_context_sched_out(task, ctxn, next);
3275 * if cgroup events exist on this CPU, then we need
3276 * to check if we have to switch out PMU state.
3277 * cgroup event are system-wide mode only
3279 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3280 perf_cgroup_sched_out(task, next);
3284 * Called with IRQs disabled
3286 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3287 enum event_type_t event_type)
3289 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3292 static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
3293 int (*func)(struct perf_event *, void *), void *data)
3295 struct perf_event **evt, *evt1, *evt2;
3298 evt1 = perf_event_groups_first(groups, -1);
3299 evt2 = perf_event_groups_first(groups, cpu);
3301 while (evt1 || evt2) {
3303 if (evt1->group_index < evt2->group_index)
3313 ret = func(*evt, data);
3317 *evt = perf_event_groups_next(*evt);
3323 struct sched_in_data {
3324 struct perf_event_context *ctx;
3325 struct perf_cpu_context *cpuctx;
3329 static int pinned_sched_in(struct perf_event *event, void *data)
3331 struct sched_in_data *sid = data;
3333 if (event->state <= PERF_EVENT_STATE_OFF)
3336 if (!event_filter_match(event))
3339 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3340 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3341 list_add_tail(&event->active_list, &sid->ctx->pinned_active);
3345 * If this pinned group hasn't been scheduled,
3346 * put it in error state.
3348 if (event->state == PERF_EVENT_STATE_INACTIVE)
3349 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3354 static int flexible_sched_in(struct perf_event *event, void *data)
3356 struct sched_in_data *sid = data;
3358 if (event->state <= PERF_EVENT_STATE_OFF)
3361 if (!event_filter_match(event))
3364 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3365 int ret = group_sched_in(event, sid->cpuctx, sid->ctx);
3367 sid->can_add_hw = 0;
3368 sid->ctx->rotate_necessary = 1;
3371 list_add_tail(&event->active_list, &sid->ctx->flexible_active);
3378 ctx_pinned_sched_in(struct perf_event_context *ctx,
3379 struct perf_cpu_context *cpuctx)
3381 struct sched_in_data sid = {
3387 visit_groups_merge(&ctx->pinned_groups,
3389 pinned_sched_in, &sid);
3393 ctx_flexible_sched_in(struct perf_event_context *ctx,
3394 struct perf_cpu_context *cpuctx)
3396 struct sched_in_data sid = {
3402 visit_groups_merge(&ctx->flexible_groups,
3404 flexible_sched_in, &sid);
3408 ctx_sched_in(struct perf_event_context *ctx,
3409 struct perf_cpu_context *cpuctx,
3410 enum event_type_t event_type,
3411 struct task_struct *task)
3413 int is_active = ctx->is_active;
3416 lockdep_assert_held(&ctx->lock);
3418 if (likely(!ctx->nr_events))
3421 ctx->is_active |= (event_type | EVENT_TIME);
3424 cpuctx->task_ctx = ctx;
3426 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3429 is_active ^= ctx->is_active; /* changed bits */
3431 if (is_active & EVENT_TIME) {
3432 /* start ctx time */
3434 ctx->timestamp = now;
3435 perf_cgroup_set_timestamp(task, ctx);
3439 * First go through the list and put on any pinned groups
3440 * in order to give them the best chance of going on.
3442 if (is_active & EVENT_PINNED)
3443 ctx_pinned_sched_in(ctx, cpuctx);
3445 /* Then walk through the lower prio flexible groups */
3446 if (is_active & EVENT_FLEXIBLE)
3447 ctx_flexible_sched_in(ctx, cpuctx);
3450 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3451 enum event_type_t event_type,
3452 struct task_struct *task)
3454 struct perf_event_context *ctx = &cpuctx->ctx;
3456 ctx_sched_in(ctx, cpuctx, event_type, task);
3459 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3460 struct task_struct *task)
3462 struct perf_cpu_context *cpuctx;
3464 cpuctx = __get_cpu_context(ctx);
3465 if (cpuctx->task_ctx == ctx)
3468 perf_ctx_lock(cpuctx, ctx);
3470 * We must check ctx->nr_events while holding ctx->lock, such
3471 * that we serialize against perf_install_in_context().
3473 if (!ctx->nr_events)
3476 perf_pmu_disable(ctx->pmu);
3478 * We want to keep the following priority order:
3479 * cpu pinned (that don't need to move), task pinned,
3480 * cpu flexible, task flexible.
3482 * However, if task's ctx is not carrying any pinned
3483 * events, no need to flip the cpuctx's events around.
3485 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3486 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3487 perf_event_sched_in(cpuctx, ctx, task);
3488 perf_pmu_enable(ctx->pmu);
3491 perf_ctx_unlock(cpuctx, ctx);
3495 * Called from scheduler to add the events of the current task
3496 * with interrupts disabled.
3498 * We restore the event value and then enable it.
3500 * This does not protect us against NMI, but enable()
3501 * sets the enabled bit in the control field of event _before_
3502 * accessing the event control register. If a NMI hits, then it will
3503 * keep the event running.
3505 void __perf_event_task_sched_in(struct task_struct *prev,
3506 struct task_struct *task)
3508 struct perf_event_context *ctx;
3512 * If cgroup events exist on this CPU, then we need to check if we have
3513 * to switch in PMU state; cgroup event are system-wide mode only.
3515 * Since cgroup events are CPU events, we must schedule these in before
3516 * we schedule in the task events.
3518 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3519 perf_cgroup_sched_in(prev, task);
3521 for_each_task_context_nr(ctxn) {
3522 ctx = task->perf_event_ctxp[ctxn];
3526 perf_event_context_sched_in(ctx, task);
3529 if (atomic_read(&nr_switch_events))
3530 perf_event_switch(task, prev, true);
3532 if (__this_cpu_read(perf_sched_cb_usages))
3533 perf_pmu_sched_task(prev, task, true);
3536 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3538 u64 frequency = event->attr.sample_freq;
3539 u64 sec = NSEC_PER_SEC;
3540 u64 divisor, dividend;
3542 int count_fls, nsec_fls, frequency_fls, sec_fls;
3544 count_fls = fls64(count);
3545 nsec_fls = fls64(nsec);
3546 frequency_fls = fls64(frequency);
3550 * We got @count in @nsec, with a target of sample_freq HZ
3551 * the target period becomes:
3554 * period = -------------------
3555 * @nsec * sample_freq
3560 * Reduce accuracy by one bit such that @a and @b converge
3561 * to a similar magnitude.
3563 #define REDUCE_FLS(a, b) \
3565 if (a##_fls > b##_fls) { \
3575 * Reduce accuracy until either term fits in a u64, then proceed with
3576 * the other, so that finally we can do a u64/u64 division.
3578 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3579 REDUCE_FLS(nsec, frequency);
3580 REDUCE_FLS(sec, count);
3583 if (count_fls + sec_fls > 64) {
3584 divisor = nsec * frequency;
3586 while (count_fls + sec_fls > 64) {
3587 REDUCE_FLS(count, sec);
3591 dividend = count * sec;
3593 dividend = count * sec;
3595 while (nsec_fls + frequency_fls > 64) {
3596 REDUCE_FLS(nsec, frequency);
3600 divisor = nsec * frequency;
3606 return div64_u64(dividend, divisor);
3609 static DEFINE_PER_CPU(int, perf_throttled_count);
3610 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3612 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3614 struct hw_perf_event *hwc = &event->hw;
3615 s64 period, sample_period;
3618 period = perf_calculate_period(event, nsec, count);
3620 delta = (s64)(period - hwc->sample_period);
3621 delta = (delta + 7) / 8; /* low pass filter */
3623 sample_period = hwc->sample_period + delta;
3628 hwc->sample_period = sample_period;
3630 if (local64_read(&hwc->period_left) > 8*sample_period) {
3632 event->pmu->stop(event, PERF_EF_UPDATE);
3634 local64_set(&hwc->period_left, 0);
3637 event->pmu->start(event, PERF_EF_RELOAD);
3642 * combine freq adjustment with unthrottling to avoid two passes over the
3643 * events. At the same time, make sure, having freq events does not change
3644 * the rate of unthrottling as that would introduce bias.
3646 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3649 struct perf_event *event;
3650 struct hw_perf_event *hwc;
3651 u64 now, period = TICK_NSEC;
3655 * only need to iterate over all events iff:
3656 * - context have events in frequency mode (needs freq adjust)
3657 * - there are events to unthrottle on this cpu
3659 if (!(ctx->nr_freq || needs_unthr))
3662 raw_spin_lock(&ctx->lock);
3663 perf_pmu_disable(ctx->pmu);
3665 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3666 if (event->state != PERF_EVENT_STATE_ACTIVE)
3669 if (!event_filter_match(event))
3672 perf_pmu_disable(event->pmu);
3676 if (hwc->interrupts == MAX_INTERRUPTS) {
3677 hwc->interrupts = 0;
3678 perf_log_throttle(event, 1);
3679 event->pmu->start(event, 0);
3682 if (!event->attr.freq || !event->attr.sample_freq)
3686 * stop the event and update event->count
3688 event->pmu->stop(event, PERF_EF_UPDATE);
3690 now = local64_read(&event->count);
3691 delta = now - hwc->freq_count_stamp;
3692 hwc->freq_count_stamp = now;
3696 * reload only if value has changed
3697 * we have stopped the event so tell that
3698 * to perf_adjust_period() to avoid stopping it
3702 perf_adjust_period(event, period, delta, false);
3704 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3706 perf_pmu_enable(event->pmu);
3709 perf_pmu_enable(ctx->pmu);
3710 raw_spin_unlock(&ctx->lock);
3714 * Move @event to the tail of the @ctx's elegible events.
3716 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
3719 * Rotate the first entry last of non-pinned groups. Rotation might be
3720 * disabled by the inheritance code.
3722 if (ctx->rotate_disable)
3725 perf_event_groups_delete(&ctx->flexible_groups, event);
3726 perf_event_groups_insert(&ctx->flexible_groups, event);
3729 /* pick an event from the flexible_groups to rotate */
3730 static inline struct perf_event *
3731 ctx_event_to_rotate(struct perf_event_context *ctx)
3733 struct perf_event *event;
3735 /* pick the first active flexible event */
3736 event = list_first_entry_or_null(&ctx->flexible_active,
3737 struct perf_event, active_list);
3739 /* if no active flexible event, pick the first event */
3741 event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
3742 typeof(*event), group_node);
3746 * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
3747 * finds there are unschedulable events, it will set it again.
3749 ctx->rotate_necessary = 0;
3754 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
3756 struct perf_event *cpu_event = NULL, *task_event = NULL;
3757 struct perf_event_context *task_ctx = NULL;
3758 int cpu_rotate, task_rotate;
3761 * Since we run this from IRQ context, nobody can install new
3762 * events, thus the event count values are stable.
3765 cpu_rotate = cpuctx->ctx.rotate_necessary;
3766 task_ctx = cpuctx->task_ctx;
3767 task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
3769 if (!(cpu_rotate || task_rotate))
3772 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3773 perf_pmu_disable(cpuctx->ctx.pmu);
3776 task_event = ctx_event_to_rotate(task_ctx);
3778 cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
3781 * As per the order given at ctx_resched() first 'pop' task flexible
3782 * and then, if needed CPU flexible.
3784 if (task_event || (task_ctx && cpu_event))
3785 ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
3787 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3790 rotate_ctx(task_ctx, task_event);
3792 rotate_ctx(&cpuctx->ctx, cpu_event);
3794 perf_event_sched_in(cpuctx, task_ctx, current);
3796 perf_pmu_enable(cpuctx->ctx.pmu);
3797 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3802 void perf_event_task_tick(void)
3804 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3805 struct perf_event_context *ctx, *tmp;
3808 lockdep_assert_irqs_disabled();
3810 __this_cpu_inc(perf_throttled_seq);
3811 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3812 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3814 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3815 perf_adjust_freq_unthr_context(ctx, throttled);
3818 static int event_enable_on_exec(struct perf_event *event,
3819 struct perf_event_context *ctx)
3821 if (!event->attr.enable_on_exec)
3824 event->attr.enable_on_exec = 0;
3825 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3828 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3834 * Enable all of a task's events that have been marked enable-on-exec.
3835 * This expects task == current.
3837 static void perf_event_enable_on_exec(int ctxn)
3839 struct perf_event_context *ctx, *clone_ctx = NULL;
3840 enum event_type_t event_type = 0;
3841 struct perf_cpu_context *cpuctx;
3842 struct perf_event *event;
3843 unsigned long flags;
3846 local_irq_save(flags);
3847 ctx = current->perf_event_ctxp[ctxn];
3848 if (!ctx || !ctx->nr_events)
3851 cpuctx = __get_cpu_context(ctx);
3852 perf_ctx_lock(cpuctx, ctx);
3853 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3854 list_for_each_entry(event, &ctx->event_list, event_entry) {
3855 enabled |= event_enable_on_exec(event, ctx);
3856 event_type |= get_event_type(event);
3860 * Unclone and reschedule this context if we enabled any event.
3863 clone_ctx = unclone_ctx(ctx);
3864 ctx_resched(cpuctx, ctx, event_type);
3866 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3868 perf_ctx_unlock(cpuctx, ctx);
3871 local_irq_restore(flags);
3877 struct perf_read_data {
3878 struct perf_event *event;
3883 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3885 u16 local_pkg, event_pkg;
3887 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3888 int local_cpu = smp_processor_id();
3890 event_pkg = topology_physical_package_id(event_cpu);
3891 local_pkg = topology_physical_package_id(local_cpu);
3893 if (event_pkg == local_pkg)
3901 * Cross CPU call to read the hardware event
3903 static void __perf_event_read(void *info)
3905 struct perf_read_data *data = info;
3906 struct perf_event *sub, *event = data->event;
3907 struct perf_event_context *ctx = event->ctx;
3908 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3909 struct pmu *pmu = event->pmu;
3912 * If this is a task context, we need to check whether it is
3913 * the current task context of this cpu. If not it has been
3914 * scheduled out before the smp call arrived. In that case
3915 * event->count would have been updated to a recent sample
3916 * when the event was scheduled out.
3918 if (ctx->task && cpuctx->task_ctx != ctx)
3921 raw_spin_lock(&ctx->lock);
3922 if (ctx->is_active & EVENT_TIME) {
3923 update_context_time(ctx);
3924 update_cgrp_time_from_event(event);
3927 perf_event_update_time(event);
3929 perf_event_update_sibling_time(event);
3931 if (event->state != PERF_EVENT_STATE_ACTIVE)
3940 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3944 for_each_sibling_event(sub, event) {
3945 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3947 * Use sibling's PMU rather than @event's since
3948 * sibling could be on different (eg: software) PMU.
3950 sub->pmu->read(sub);
3954 data->ret = pmu->commit_txn(pmu);
3957 raw_spin_unlock(&ctx->lock);
3960 static inline u64 perf_event_count(struct perf_event *event)
3962 return local64_read(&event->count) + atomic64_read(&event->child_count);
3966 * NMI-safe method to read a local event, that is an event that
3968 * - either for the current task, or for this CPU
3969 * - does not have inherit set, for inherited task events
3970 * will not be local and we cannot read them atomically
3971 * - must not have a pmu::count method
3973 int perf_event_read_local(struct perf_event *event, u64 *value,
3974 u64 *enabled, u64 *running)
3976 unsigned long flags;
3980 * Disabling interrupts avoids all counter scheduling (context
3981 * switches, timer based rotation and IPIs).
3983 local_irq_save(flags);
3986 * It must not be an event with inherit set, we cannot read
3987 * all child counters from atomic context.
3989 if (event->attr.inherit) {
3994 /* If this is a per-task event, it must be for current */
3995 if ((event->attach_state & PERF_ATTACH_TASK) &&
3996 event->hw.target != current) {
4001 /* If this is a per-CPU event, it must be for this CPU */
4002 if (!(event->attach_state & PERF_ATTACH_TASK) &&
4003 event->cpu != smp_processor_id()) {
4008 /* If this is a pinned event it must be running on this CPU */
4009 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4015 * If the event is currently on this CPU, its either a per-task event,
4016 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4019 if (event->oncpu == smp_processor_id())
4020 event->pmu->read(event);
4022 *value = local64_read(&event->count);
4023 if (enabled || running) {
4024 u64 now = event->shadow_ctx_time + perf_clock();
4025 u64 __enabled, __running;
4027 __perf_update_times(event, now, &__enabled, &__running);
4029 *enabled = __enabled;
4031 *running = __running;
4034 local_irq_restore(flags);
4039 static int perf_event_read(struct perf_event *event, bool group)
4041 enum perf_event_state state = READ_ONCE(event->state);
4042 int event_cpu, ret = 0;
4045 * If event is enabled and currently active on a CPU, update the
4046 * value in the event structure:
4049 if (state == PERF_EVENT_STATE_ACTIVE) {
4050 struct perf_read_data data;
4053 * Orders the ->state and ->oncpu loads such that if we see
4054 * ACTIVE we must also see the right ->oncpu.
4056 * Matches the smp_wmb() from event_sched_in().
4060 event_cpu = READ_ONCE(event->oncpu);
4061 if ((unsigned)event_cpu >= nr_cpu_ids)
4064 data = (struct perf_read_data){
4071 event_cpu = __perf_event_read_cpu(event, event_cpu);
4074 * Purposely ignore the smp_call_function_single() return
4077 * If event_cpu isn't a valid CPU it means the event got
4078 * scheduled out and that will have updated the event count.
4080 * Therefore, either way, we'll have an up-to-date event count
4083 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4087 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4088 struct perf_event_context *ctx = event->ctx;
4089 unsigned long flags;
4091 raw_spin_lock_irqsave(&ctx->lock, flags);
4092 state = event->state;
4093 if (state != PERF_EVENT_STATE_INACTIVE) {
4094 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4099 * May read while context is not active (e.g., thread is
4100 * blocked), in that case we cannot update context time
4102 if (ctx->is_active & EVENT_TIME) {
4103 update_context_time(ctx);
4104 update_cgrp_time_from_event(event);
4107 perf_event_update_time(event);
4109 perf_event_update_sibling_time(event);
4110 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4117 * Initialize the perf_event context in a task_struct:
4119 static void __perf_event_init_context(struct perf_event_context *ctx)
4121 raw_spin_lock_init(&ctx->lock);
4122 mutex_init(&ctx->mutex);
4123 INIT_LIST_HEAD(&ctx->active_ctx_list);
4124 perf_event_groups_init(&ctx->pinned_groups);
4125 perf_event_groups_init(&ctx->flexible_groups);
4126 INIT_LIST_HEAD(&ctx->event_list);
4127 INIT_LIST_HEAD(&ctx->pinned_active);
4128 INIT_LIST_HEAD(&ctx->flexible_active);
4129 atomic_set(&ctx->refcount, 1);
4132 static struct perf_event_context *
4133 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4135 struct perf_event_context *ctx;
4137 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4141 __perf_event_init_context(ctx);
4144 get_task_struct(task);
4151 static struct task_struct *
4152 find_lively_task_by_vpid(pid_t vpid)
4154 struct task_struct *task;
4160 task = find_task_by_vpid(vpid);
4162 get_task_struct(task);
4166 return ERR_PTR(-ESRCH);
4172 * Returns a matching context with refcount and pincount.
4174 static struct perf_event_context *
4175 find_get_context(struct pmu *pmu, struct task_struct *task,
4176 struct perf_event *event)
4178 struct perf_event_context *ctx, *clone_ctx = NULL;
4179 struct perf_cpu_context *cpuctx;
4180 void *task_ctx_data = NULL;
4181 unsigned long flags;
4183 int cpu = event->cpu;
4186 /* Must be root to operate on a CPU event: */
4187 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
4188 return ERR_PTR(-EACCES);
4190 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4193 raw_spin_lock_irqsave(&ctx->lock, flags);
4195 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4201 ctxn = pmu->task_ctx_nr;
4205 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4206 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4207 if (!task_ctx_data) {
4214 ctx = perf_lock_task_context(task, ctxn, &flags);
4216 clone_ctx = unclone_ctx(ctx);
4219 if (task_ctx_data && !ctx->task_ctx_data) {
4220 ctx->task_ctx_data = task_ctx_data;
4221 task_ctx_data = NULL;
4223 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4228 ctx = alloc_perf_context(pmu, task);
4233 if (task_ctx_data) {
4234 ctx->task_ctx_data = task_ctx_data;
4235 task_ctx_data = NULL;
4239 mutex_lock(&task->perf_event_mutex);
4241 * If it has already passed perf_event_exit_task().
4242 * we must see PF_EXITING, it takes this mutex too.
4244 if (task->flags & PF_EXITING)
4246 else if (task->perf_event_ctxp[ctxn])
4251 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4253 mutex_unlock(&task->perf_event_mutex);
4255 if (unlikely(err)) {
4264 kfree(task_ctx_data);
4268 kfree(task_ctx_data);
4269 return ERR_PTR(err);
4272 static void perf_event_free_filter(struct perf_event *event);
4273 static void perf_event_free_bpf_prog(struct perf_event *event);
4275 static void free_event_rcu(struct rcu_head *head)
4277 struct perf_event *event;
4279 event = container_of(head, struct perf_event, rcu_head);
4281 put_pid_ns(event->ns);
4282 perf_event_free_filter(event);
4286 static void ring_buffer_attach(struct perf_event *event,
4287 struct ring_buffer *rb);
4289 static void detach_sb_event(struct perf_event *event)
4291 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4293 raw_spin_lock(&pel->lock);
4294 list_del_rcu(&event->sb_list);
4295 raw_spin_unlock(&pel->lock);
4298 static bool is_sb_event(struct perf_event *event)
4300 struct perf_event_attr *attr = &event->attr;
4305 if (event->attach_state & PERF_ATTACH_TASK)
4308 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4309 attr->comm || attr->comm_exec ||
4311 attr->context_switch)
4316 static void unaccount_pmu_sb_event(struct perf_event *event)
4318 if (is_sb_event(event))
4319 detach_sb_event(event);
4322 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4327 if (is_cgroup_event(event))
4328 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4331 #ifdef CONFIG_NO_HZ_FULL
4332 static DEFINE_SPINLOCK(nr_freq_lock);
4335 static void unaccount_freq_event_nohz(void)
4337 #ifdef CONFIG_NO_HZ_FULL
4338 spin_lock(&nr_freq_lock);
4339 if (atomic_dec_and_test(&nr_freq_events))
4340 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4341 spin_unlock(&nr_freq_lock);
4345 static void unaccount_freq_event(void)
4347 if (tick_nohz_full_enabled())
4348 unaccount_freq_event_nohz();
4350 atomic_dec(&nr_freq_events);
4353 static void unaccount_event(struct perf_event *event)
4360 if (event->attach_state & PERF_ATTACH_TASK)
4362 if (event->attr.mmap || event->attr.mmap_data)
4363 atomic_dec(&nr_mmap_events);
4364 if (event->attr.comm)
4365 atomic_dec(&nr_comm_events);
4366 if (event->attr.namespaces)
4367 atomic_dec(&nr_namespaces_events);
4368 if (event->attr.task)
4369 atomic_dec(&nr_task_events);
4370 if (event->attr.freq)
4371 unaccount_freq_event();
4372 if (event->attr.context_switch) {
4374 atomic_dec(&nr_switch_events);
4376 if (is_cgroup_event(event))
4378 if (has_branch_stack(event))
4382 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4383 schedule_delayed_work(&perf_sched_work, HZ);
4386 unaccount_event_cpu(event, event->cpu);
4388 unaccount_pmu_sb_event(event);
4391 static void perf_sched_delayed(struct work_struct *work)
4393 mutex_lock(&perf_sched_mutex);
4394 if (atomic_dec_and_test(&perf_sched_count))
4395 static_branch_disable(&perf_sched_events);
4396 mutex_unlock(&perf_sched_mutex);
4400 * The following implement mutual exclusion of events on "exclusive" pmus
4401 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4402 * at a time, so we disallow creating events that might conflict, namely:
4404 * 1) cpu-wide events in the presence of per-task events,
4405 * 2) per-task events in the presence of cpu-wide events,
4406 * 3) two matching events on the same context.
4408 * The former two cases are handled in the allocation path (perf_event_alloc(),
4409 * _free_event()), the latter -- before the first perf_install_in_context().
4411 static int exclusive_event_init(struct perf_event *event)
4413 struct pmu *pmu = event->pmu;
4415 if (!is_exclusive_pmu(pmu))
4419 * Prevent co-existence of per-task and cpu-wide events on the
4420 * same exclusive pmu.
4422 * Negative pmu::exclusive_cnt means there are cpu-wide
4423 * events on this "exclusive" pmu, positive means there are
4426 * Since this is called in perf_event_alloc() path, event::ctx
4427 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4428 * to mean "per-task event", because unlike other attach states it
4429 * never gets cleared.
4431 if (event->attach_state & PERF_ATTACH_TASK) {
4432 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4435 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4442 static void exclusive_event_destroy(struct perf_event *event)
4444 struct pmu *pmu = event->pmu;
4446 if (!is_exclusive_pmu(pmu))
4449 /* see comment in exclusive_event_init() */
4450 if (event->attach_state & PERF_ATTACH_TASK)
4451 atomic_dec(&pmu->exclusive_cnt);
4453 atomic_inc(&pmu->exclusive_cnt);
4456 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4458 if ((e1->pmu == e2->pmu) &&
4459 (e1->cpu == e2->cpu ||
4466 static bool exclusive_event_installable(struct perf_event *event,
4467 struct perf_event_context *ctx)
4469 struct perf_event *iter_event;
4470 struct pmu *pmu = event->pmu;
4472 lockdep_assert_held(&ctx->mutex);
4474 if (!is_exclusive_pmu(pmu))
4477 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4478 if (exclusive_event_match(iter_event, event))
4485 static void perf_addr_filters_splice(struct perf_event *event,
4486 struct list_head *head);
4488 static void _free_event(struct perf_event *event)
4490 irq_work_sync(&event->pending);
4492 unaccount_event(event);
4496 * Can happen when we close an event with re-directed output.
4498 * Since we have a 0 refcount, perf_mmap_close() will skip
4499 * over us; possibly making our ring_buffer_put() the last.
4501 mutex_lock(&event->mmap_mutex);
4502 ring_buffer_attach(event, NULL);
4503 mutex_unlock(&event->mmap_mutex);
4506 if (is_cgroup_event(event))
4507 perf_detach_cgroup(event);
4509 if (!event->parent) {
4510 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4511 put_callchain_buffers();
4514 perf_event_free_bpf_prog(event);
4515 perf_addr_filters_splice(event, NULL);
4516 kfree(event->addr_filter_ranges);
4519 event->destroy(event);
4522 * Must be after ->destroy(), due to uprobe_perf_close() using
4525 if (event->hw.target)
4526 put_task_struct(event->hw.target);
4529 * perf_event_free_task() relies on put_ctx() being 'last', in particular
4530 * all task references must be cleaned up.
4533 put_ctx(event->ctx);
4535 exclusive_event_destroy(event);
4536 module_put(event->pmu->module);
4538 call_rcu(&event->rcu_head, free_event_rcu);
4542 * Used to free events which have a known refcount of 1, such as in error paths
4543 * where the event isn't exposed yet and inherited events.
4545 static void free_event(struct perf_event *event)
4547 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4548 "unexpected event refcount: %ld; ptr=%p\n",
4549 atomic_long_read(&event->refcount), event)) {
4550 /* leak to avoid use-after-free */
4558 * Remove user event from the owner task.
4560 static void perf_remove_from_owner(struct perf_event *event)
4562 struct task_struct *owner;
4566 * Matches the smp_store_release() in perf_event_exit_task(). If we
4567 * observe !owner it means the list deletion is complete and we can
4568 * indeed free this event, otherwise we need to serialize on
4569 * owner->perf_event_mutex.
4571 owner = READ_ONCE(event->owner);
4574 * Since delayed_put_task_struct() also drops the last
4575 * task reference we can safely take a new reference
4576 * while holding the rcu_read_lock().
4578 get_task_struct(owner);
4584 * If we're here through perf_event_exit_task() we're already
4585 * holding ctx->mutex which would be an inversion wrt. the
4586 * normal lock order.
4588 * However we can safely take this lock because its the child
4591 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4594 * We have to re-check the event->owner field, if it is cleared
4595 * we raced with perf_event_exit_task(), acquiring the mutex
4596 * ensured they're done, and we can proceed with freeing the
4600 list_del_init(&event->owner_entry);
4601 smp_store_release(&event->owner, NULL);
4603 mutex_unlock(&owner->perf_event_mutex);
4604 put_task_struct(owner);
4608 static void put_event(struct perf_event *event)
4610 if (!atomic_long_dec_and_test(&event->refcount))
4617 * Kill an event dead; while event:refcount will preserve the event
4618 * object, it will not preserve its functionality. Once the last 'user'
4619 * gives up the object, we'll destroy the thing.
4621 int perf_event_release_kernel(struct perf_event *event)
4623 struct perf_event_context *ctx = event->ctx;
4624 struct perf_event *child, *tmp;
4625 LIST_HEAD(free_list);
4628 * If we got here through err_file: fput(event_file); we will not have
4629 * attached to a context yet.
4632 WARN_ON_ONCE(event->attach_state &
4633 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4637 if (!is_kernel_event(event))
4638 perf_remove_from_owner(event);
4640 ctx = perf_event_ctx_lock(event);
4641 WARN_ON_ONCE(ctx->parent_ctx);
4642 perf_remove_from_context(event, DETACH_GROUP);
4644 raw_spin_lock_irq(&ctx->lock);
4646 * Mark this event as STATE_DEAD, there is no external reference to it
4649 * Anybody acquiring event->child_mutex after the below loop _must_
4650 * also see this, most importantly inherit_event() which will avoid
4651 * placing more children on the list.
4653 * Thus this guarantees that we will in fact observe and kill _ALL_
4656 event->state = PERF_EVENT_STATE_DEAD;
4657 raw_spin_unlock_irq(&ctx->lock);
4659 perf_event_ctx_unlock(event, ctx);
4662 mutex_lock(&event->child_mutex);
4663 list_for_each_entry(child, &event->child_list, child_list) {
4666 * Cannot change, child events are not migrated, see the
4667 * comment with perf_event_ctx_lock_nested().
4669 ctx = READ_ONCE(child->ctx);
4671 * Since child_mutex nests inside ctx::mutex, we must jump
4672 * through hoops. We start by grabbing a reference on the ctx.
4674 * Since the event cannot get freed while we hold the
4675 * child_mutex, the context must also exist and have a !0
4681 * Now that we have a ctx ref, we can drop child_mutex, and
4682 * acquire ctx::mutex without fear of it going away. Then we
4683 * can re-acquire child_mutex.
4685 mutex_unlock(&event->child_mutex);
4686 mutex_lock(&ctx->mutex);
4687 mutex_lock(&event->child_mutex);
4690 * Now that we hold ctx::mutex and child_mutex, revalidate our
4691 * state, if child is still the first entry, it didn't get freed
4692 * and we can continue doing so.
4694 tmp = list_first_entry_or_null(&event->child_list,
4695 struct perf_event, child_list);
4697 perf_remove_from_context(child, DETACH_GROUP);
4698 list_move(&child->child_list, &free_list);
4700 * This matches the refcount bump in inherit_event();
4701 * this can't be the last reference.
4706 mutex_unlock(&event->child_mutex);
4707 mutex_unlock(&ctx->mutex);
4711 mutex_unlock(&event->child_mutex);
4713 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4714 void *var = &child->ctx->refcount;
4716 list_del(&child->child_list);
4720 * Wake any perf_event_free_task() waiting for this event to be
4723 smp_mb(); /* pairs with wait_var_event() */
4728 put_event(event); /* Must be the 'last' reference */
4731 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4734 * Called when the last reference to the file is gone.
4736 static int perf_release(struct inode *inode, struct file *file)
4738 perf_event_release_kernel(file->private_data);
4742 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4744 struct perf_event *child;
4750 mutex_lock(&event->child_mutex);
4752 (void)perf_event_read(event, false);
4753 total += perf_event_count(event);
4755 *enabled += event->total_time_enabled +
4756 atomic64_read(&event->child_total_time_enabled);
4757 *running += event->total_time_running +
4758 atomic64_read(&event->child_total_time_running);
4760 list_for_each_entry(child, &event->child_list, child_list) {
4761 (void)perf_event_read(child, false);
4762 total += perf_event_count(child);
4763 *enabled += child->total_time_enabled;
4764 *running += child->total_time_running;
4766 mutex_unlock(&event->child_mutex);
4771 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4773 struct perf_event_context *ctx;
4776 ctx = perf_event_ctx_lock(event);
4777 count = __perf_event_read_value(event, enabled, running);
4778 perf_event_ctx_unlock(event, ctx);
4782 EXPORT_SYMBOL_GPL(perf_event_read_value);
4784 static int __perf_read_group_add(struct perf_event *leader,
4785 u64 read_format, u64 *values)
4787 struct perf_event_context *ctx = leader->ctx;
4788 struct perf_event *sub, *parent;
4789 unsigned long flags;
4790 int n = 1; /* skip @nr */
4793 ret = perf_event_read(leader, true);
4797 raw_spin_lock_irqsave(&ctx->lock, flags);
4799 * Verify the grouping between the parent and child (inherited)
4800 * events is still in tact.
4803 * - leader->ctx->lock pins leader->sibling_list
4804 * - parent->child_mutex pins parent->child_list
4805 * - parent->ctx->mutex pins parent->sibling_list
4807 * Because parent->ctx != leader->ctx (and child_list nests inside
4808 * ctx->mutex), group destruction is not atomic between children, also
4809 * see perf_event_release_kernel(). Additionally, parent can grow the
4812 * Therefore it is possible to have parent and child groups in a
4813 * different configuration and summing over such a beast makes no sense
4818 parent = leader->parent;
4820 (parent->group_generation != leader->group_generation ||
4821 parent->nr_siblings != leader->nr_siblings)) {
4827 * Since we co-schedule groups, {enabled,running} times of siblings
4828 * will be identical to those of the leader, so we only publish one
4831 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4832 values[n++] += leader->total_time_enabled +
4833 atomic64_read(&leader->child_total_time_enabled);
4836 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4837 values[n++] += leader->total_time_running +
4838 atomic64_read(&leader->child_total_time_running);
4842 * Write {count,id} tuples for every sibling.
4844 values[n++] += perf_event_count(leader);
4845 if (read_format & PERF_FORMAT_ID)
4846 values[n++] = primary_event_id(leader);
4847 if (read_format & PERF_FORMAT_LOST)
4848 values[n++] = atomic64_read(&leader->lost_samples);
4850 for_each_sibling_event(sub, leader) {
4851 values[n++] += perf_event_count(sub);
4852 if (read_format & PERF_FORMAT_ID)
4853 values[n++] = primary_event_id(sub);
4854 if (read_format & PERF_FORMAT_LOST)
4855 values[n++] = atomic64_read(&sub->lost_samples);
4859 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4863 static int perf_read_group(struct perf_event *event,
4864 u64 read_format, char __user *buf)
4866 struct perf_event *leader = event->group_leader, *child;
4867 struct perf_event_context *ctx = leader->ctx;
4871 lockdep_assert_held(&ctx->mutex);
4873 values = kzalloc(event->read_size, GFP_KERNEL);
4877 values[0] = 1 + leader->nr_siblings;
4879 mutex_lock(&leader->child_mutex);
4881 ret = __perf_read_group_add(leader, read_format, values);
4885 list_for_each_entry(child, &leader->child_list, child_list) {
4886 ret = __perf_read_group_add(child, read_format, values);
4891 mutex_unlock(&leader->child_mutex);
4893 ret = event->read_size;
4894 if (copy_to_user(buf, values, event->read_size))
4899 mutex_unlock(&leader->child_mutex);
4905 static int perf_read_one(struct perf_event *event,
4906 u64 read_format, char __user *buf)
4908 u64 enabled, running;
4912 values[n++] = __perf_event_read_value(event, &enabled, &running);
4913 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4914 values[n++] = enabled;
4915 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4916 values[n++] = running;
4917 if (read_format & PERF_FORMAT_ID)
4918 values[n++] = primary_event_id(event);
4919 if (read_format & PERF_FORMAT_LOST)
4920 values[n++] = atomic64_read(&event->lost_samples);
4922 if (copy_to_user(buf, values, n * sizeof(u64)))
4925 return n * sizeof(u64);
4928 static bool is_event_hup(struct perf_event *event)
4932 if (event->state > PERF_EVENT_STATE_EXIT)
4935 mutex_lock(&event->child_mutex);
4936 no_children = list_empty(&event->child_list);
4937 mutex_unlock(&event->child_mutex);
4942 * Read the performance event - simple non blocking version for now
4945 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4947 u64 read_format = event->attr.read_format;
4951 * Return end-of-file for a read on an event that is in
4952 * error state (i.e. because it was pinned but it couldn't be
4953 * scheduled on to the CPU at some point).
4955 if (event->state == PERF_EVENT_STATE_ERROR)
4958 if (count < event->read_size)
4961 WARN_ON_ONCE(event->ctx->parent_ctx);
4962 if (read_format & PERF_FORMAT_GROUP)
4963 ret = perf_read_group(event, read_format, buf);
4965 ret = perf_read_one(event, read_format, buf);
4971 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4973 struct perf_event *event = file->private_data;
4974 struct perf_event_context *ctx;
4977 ctx = perf_event_ctx_lock(event);
4978 ret = __perf_read(event, buf, count);
4979 perf_event_ctx_unlock(event, ctx);
4984 static __poll_t perf_poll(struct file *file, poll_table *wait)
4986 struct perf_event *event = file->private_data;
4987 struct ring_buffer *rb;
4988 __poll_t events = EPOLLHUP;
4990 poll_wait(file, &event->waitq, wait);
4992 if (is_event_hup(event))
4996 * Pin the event->rb by taking event->mmap_mutex; otherwise
4997 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4999 mutex_lock(&event->mmap_mutex);
5002 events = atomic_xchg(&rb->poll, 0);
5003 mutex_unlock(&event->mmap_mutex);
5007 static void _perf_event_reset(struct perf_event *event)
5009 (void)perf_event_read(event, false);
5010 local64_set(&event->count, 0);
5011 perf_event_update_userpage(event);
5015 * Holding the top-level event's child_mutex means that any
5016 * descendant process that has inherited this event will block
5017 * in perf_event_exit_event() if it goes to exit, thus satisfying the
5018 * task existence requirements of perf_event_enable/disable.
5020 static void perf_event_for_each_child(struct perf_event *event,
5021 void (*func)(struct perf_event *))
5023 struct perf_event *child;
5025 WARN_ON_ONCE(event->ctx->parent_ctx);
5027 mutex_lock(&event->child_mutex);
5029 list_for_each_entry(child, &event->child_list, child_list)
5031 mutex_unlock(&event->child_mutex);
5034 static void perf_event_for_each(struct perf_event *event,
5035 void (*func)(struct perf_event *))
5037 struct perf_event_context *ctx = event->ctx;
5038 struct perf_event *sibling;
5040 lockdep_assert_held(&ctx->mutex);
5042 event = event->group_leader;
5044 perf_event_for_each_child(event, func);
5045 for_each_sibling_event(sibling, event)
5046 perf_event_for_each_child(sibling, func);
5049 static void __perf_event_period(struct perf_event *event,
5050 struct perf_cpu_context *cpuctx,
5051 struct perf_event_context *ctx,
5054 u64 value = *((u64 *)info);
5057 if (event->attr.freq) {
5058 event->attr.sample_freq = value;
5060 event->attr.sample_period = value;
5061 event->hw.sample_period = value;
5064 active = (event->state == PERF_EVENT_STATE_ACTIVE);
5066 perf_pmu_disable(ctx->pmu);
5068 * We could be throttled; unthrottle now to avoid the tick
5069 * trying to unthrottle while we already re-started the event.
5071 if (event->hw.interrupts == MAX_INTERRUPTS) {
5072 event->hw.interrupts = 0;
5073 perf_log_throttle(event, 1);
5075 event->pmu->stop(event, PERF_EF_UPDATE);
5078 local64_set(&event->hw.period_left, 0);
5081 event->pmu->start(event, PERF_EF_RELOAD);
5082 perf_pmu_enable(ctx->pmu);
5086 static int perf_event_check_period(struct perf_event *event, u64 value)
5088 return event->pmu->check_period(event, value);
5091 static int perf_event_period(struct perf_event *event, u64 __user *arg)
5095 if (!is_sampling_event(event))
5098 if (copy_from_user(&value, arg, sizeof(value)))
5104 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5107 if (perf_event_check_period(event, value))
5110 if (!event->attr.freq && (value & (1ULL << 63)))
5113 event_function_call(event, __perf_event_period, &value);
5118 static const struct file_operations perf_fops;
5120 static inline int perf_fget_light(int fd, struct fd *p)
5122 struct fd f = fdget(fd);
5126 if (f.file->f_op != &perf_fops) {
5134 static int perf_event_set_output(struct perf_event *event,
5135 struct perf_event *output_event);
5136 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5137 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5138 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5139 struct perf_event_attr *attr);
5141 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5143 void (*func)(struct perf_event *);
5147 case PERF_EVENT_IOC_ENABLE:
5148 func = _perf_event_enable;
5150 case PERF_EVENT_IOC_DISABLE:
5151 func = _perf_event_disable;
5153 case PERF_EVENT_IOC_RESET:
5154 func = _perf_event_reset;
5157 case PERF_EVENT_IOC_REFRESH:
5158 return _perf_event_refresh(event, arg);
5160 case PERF_EVENT_IOC_PERIOD:
5161 return perf_event_period(event, (u64 __user *)arg);
5163 case PERF_EVENT_IOC_ID:
5165 u64 id = primary_event_id(event);
5167 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5172 case PERF_EVENT_IOC_SET_OUTPUT:
5176 struct perf_event *output_event;
5178 ret = perf_fget_light(arg, &output);
5181 output_event = output.file->private_data;
5182 ret = perf_event_set_output(event, output_event);
5185 ret = perf_event_set_output(event, NULL);
5190 case PERF_EVENT_IOC_SET_FILTER:
5191 return perf_event_set_filter(event, (void __user *)arg);
5193 case PERF_EVENT_IOC_SET_BPF:
5194 return perf_event_set_bpf_prog(event, arg);
5196 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5197 struct ring_buffer *rb;
5200 rb = rcu_dereference(event->rb);
5201 if (!rb || !rb->nr_pages) {
5205 rb_toggle_paused(rb, !!arg);
5210 case PERF_EVENT_IOC_QUERY_BPF:
5211 return perf_event_query_prog_array(event, (void __user *)arg);
5213 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5214 struct perf_event_attr new_attr;
5215 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5221 return perf_event_modify_attr(event, &new_attr);
5227 if (flags & PERF_IOC_FLAG_GROUP)
5228 perf_event_for_each(event, func);
5230 perf_event_for_each_child(event, func);
5235 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5237 struct perf_event *event = file->private_data;
5238 struct perf_event_context *ctx;
5241 ctx = perf_event_ctx_lock(event);
5242 ret = _perf_ioctl(event, cmd, arg);
5243 perf_event_ctx_unlock(event, ctx);
5248 #ifdef CONFIG_COMPAT
5249 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5252 switch (_IOC_NR(cmd)) {
5253 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5254 case _IOC_NR(PERF_EVENT_IOC_ID):
5255 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5256 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5257 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5258 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5259 cmd &= ~IOCSIZE_MASK;
5260 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5264 return perf_ioctl(file, cmd, arg);
5267 # define perf_compat_ioctl NULL
5270 int perf_event_task_enable(void)
5272 struct perf_event_context *ctx;
5273 struct perf_event *event;
5275 mutex_lock(¤t->perf_event_mutex);
5276 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5277 ctx = perf_event_ctx_lock(event);
5278 perf_event_for_each_child(event, _perf_event_enable);
5279 perf_event_ctx_unlock(event, ctx);
5281 mutex_unlock(¤t->perf_event_mutex);
5286 int perf_event_task_disable(void)
5288 struct perf_event_context *ctx;
5289 struct perf_event *event;
5291 mutex_lock(¤t->perf_event_mutex);
5292 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5293 ctx = perf_event_ctx_lock(event);
5294 perf_event_for_each_child(event, _perf_event_disable);
5295 perf_event_ctx_unlock(event, ctx);
5297 mutex_unlock(¤t->perf_event_mutex);
5302 static int perf_event_index(struct perf_event *event)
5304 if (event->hw.state & PERF_HES_STOPPED)
5307 if (event->state != PERF_EVENT_STATE_ACTIVE)
5310 return event->pmu->event_idx(event);
5313 static void calc_timer_values(struct perf_event *event,
5320 *now = perf_clock();
5321 ctx_time = event->shadow_ctx_time + *now;
5322 __perf_update_times(event, ctx_time, enabled, running);
5325 static void perf_event_init_userpage(struct perf_event *event)
5327 struct perf_event_mmap_page *userpg;
5328 struct ring_buffer *rb;
5331 rb = rcu_dereference(event->rb);
5335 userpg = rb->user_page;
5337 /* Allow new userspace to detect that bit 0 is deprecated */
5338 userpg->cap_bit0_is_deprecated = 1;
5339 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5340 userpg->data_offset = PAGE_SIZE;
5341 userpg->data_size = perf_data_size(rb);
5347 void __weak arch_perf_update_userpage(
5348 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5353 * Callers need to ensure there can be no nesting of this function, otherwise
5354 * the seqlock logic goes bad. We can not serialize this because the arch
5355 * code calls this from NMI context.
5357 void perf_event_update_userpage(struct perf_event *event)
5359 struct perf_event_mmap_page *userpg;
5360 struct ring_buffer *rb;
5361 u64 enabled, running, now;
5364 rb = rcu_dereference(event->rb);
5369 * compute total_time_enabled, total_time_running
5370 * based on snapshot values taken when the event
5371 * was last scheduled in.
5373 * we cannot simply called update_context_time()
5374 * because of locking issue as we can be called in
5377 calc_timer_values(event, &now, &enabled, &running);
5379 userpg = rb->user_page;
5381 * Disable preemption to guarantee consistent time stamps are stored to
5387 userpg->index = perf_event_index(event);
5388 userpg->offset = perf_event_count(event);
5390 userpg->offset -= local64_read(&event->hw.prev_count);
5392 userpg->time_enabled = enabled +
5393 atomic64_read(&event->child_total_time_enabled);
5395 userpg->time_running = running +
5396 atomic64_read(&event->child_total_time_running);
5398 arch_perf_update_userpage(event, userpg, now);
5406 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5408 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5410 struct perf_event *event = vmf->vma->vm_file->private_data;
5411 struct ring_buffer *rb;
5412 vm_fault_t ret = VM_FAULT_SIGBUS;
5414 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5415 if (vmf->pgoff == 0)
5421 rb = rcu_dereference(event->rb);
5425 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5428 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5432 get_page(vmf->page);
5433 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5434 vmf->page->index = vmf->pgoff;
5443 static void ring_buffer_attach(struct perf_event *event,
5444 struct ring_buffer *rb)
5446 struct ring_buffer *old_rb = NULL;
5447 unsigned long flags;
5451 * Should be impossible, we set this when removing
5452 * event->rb_entry and wait/clear when adding event->rb_entry.
5454 WARN_ON_ONCE(event->rcu_pending);
5457 spin_lock_irqsave(&old_rb->event_lock, flags);
5458 list_del_rcu(&event->rb_entry);
5459 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5461 event->rcu_batches = get_state_synchronize_rcu();
5462 event->rcu_pending = 1;
5466 if (event->rcu_pending) {
5467 cond_synchronize_rcu(event->rcu_batches);
5468 event->rcu_pending = 0;
5471 spin_lock_irqsave(&rb->event_lock, flags);
5472 list_add_rcu(&event->rb_entry, &rb->event_list);
5473 spin_unlock_irqrestore(&rb->event_lock, flags);
5477 * Avoid racing with perf_mmap_close(AUX): stop the event
5478 * before swizzling the event::rb pointer; if it's getting
5479 * unmapped, its aux_mmap_count will be 0 and it won't
5480 * restart. See the comment in __perf_pmu_output_stop().
5482 * Data will inevitably be lost when set_output is done in
5483 * mid-air, but then again, whoever does it like this is
5484 * not in for the data anyway.
5487 perf_event_stop(event, 0);
5489 rcu_assign_pointer(event->rb, rb);
5492 ring_buffer_put(old_rb);
5494 * Since we detached before setting the new rb, so that we
5495 * could attach the new rb, we could have missed a wakeup.
5498 wake_up_all(&event->waitq);
5502 static void ring_buffer_wakeup(struct perf_event *event)
5504 struct ring_buffer *rb;
5507 rb = rcu_dereference(event->rb);
5509 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5510 wake_up_all(&event->waitq);
5515 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5517 struct ring_buffer *rb;
5520 rb = rcu_dereference(event->rb);
5522 if (!atomic_inc_not_zero(&rb->refcount))
5530 void ring_buffer_put(struct ring_buffer *rb)
5532 if (!atomic_dec_and_test(&rb->refcount))
5535 WARN_ON_ONCE(!list_empty(&rb->event_list));
5537 call_rcu(&rb->rcu_head, rb_free_rcu);
5540 static void perf_mmap_open(struct vm_area_struct *vma)
5542 struct perf_event *event = vma->vm_file->private_data;
5544 atomic_inc(&event->mmap_count);
5545 atomic_inc(&event->rb->mmap_count);
5548 atomic_inc(&event->rb->aux_mmap_count);
5550 if (event->pmu->event_mapped)
5551 event->pmu->event_mapped(event, vma->vm_mm);
5554 static void perf_pmu_output_stop(struct perf_event *event);
5557 * A buffer can be mmap()ed multiple times; either directly through the same
5558 * event, or through other events by use of perf_event_set_output().
5560 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5561 * the buffer here, where we still have a VM context. This means we need
5562 * to detach all events redirecting to us.
5564 static void perf_mmap_close(struct vm_area_struct *vma)
5566 struct perf_event *event = vma->vm_file->private_data;
5567 struct ring_buffer *rb = ring_buffer_get(event);
5568 struct user_struct *mmap_user = rb->mmap_user;
5569 int mmap_locked = rb->mmap_locked;
5570 unsigned long size = perf_data_size(rb);
5571 bool detach_rest = false;
5573 if (event->pmu->event_unmapped)
5574 event->pmu->event_unmapped(event, vma->vm_mm);
5577 * rb->aux_mmap_count will always drop before rb->mmap_count and
5578 * event->mmap_count, so it is ok to use event->mmap_mutex to
5579 * serialize with perf_mmap here.
5581 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5582 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5584 * Stop all AUX events that are writing to this buffer,
5585 * so that we can free its AUX pages and corresponding PMU
5586 * data. Note that after rb::aux_mmap_count dropped to zero,
5587 * they won't start any more (see perf_aux_output_begin()).
5589 perf_pmu_output_stop(event);
5591 /* now it's safe to free the pages */
5592 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5593 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5595 /* this has to be the last one */
5597 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5599 mutex_unlock(&event->mmap_mutex);
5602 if (atomic_dec_and_test(&rb->mmap_count))
5605 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5608 ring_buffer_attach(event, NULL);
5609 mutex_unlock(&event->mmap_mutex);
5611 /* If there's still other mmap()s of this buffer, we're done. */
5616 * No other mmap()s, detach from all other events that might redirect
5617 * into the now unreachable buffer. Somewhat complicated by the
5618 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5622 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5623 if (!atomic_long_inc_not_zero(&event->refcount)) {
5625 * This event is en-route to free_event() which will
5626 * detach it and remove it from the list.
5632 mutex_lock(&event->mmap_mutex);
5634 * Check we didn't race with perf_event_set_output() which can
5635 * swizzle the rb from under us while we were waiting to
5636 * acquire mmap_mutex.
5638 * If we find a different rb; ignore this event, a next
5639 * iteration will no longer find it on the list. We have to
5640 * still restart the iteration to make sure we're not now
5641 * iterating the wrong list.
5643 if (event->rb == rb)
5644 ring_buffer_attach(event, NULL);
5646 mutex_unlock(&event->mmap_mutex);
5650 * Restart the iteration; either we're on the wrong list or
5651 * destroyed its integrity by doing a deletion.
5658 * It could be there's still a few 0-ref events on the list; they'll
5659 * get cleaned up by free_event() -- they'll also still have their
5660 * ref on the rb and will free it whenever they are done with it.
5662 * Aside from that, this buffer is 'fully' detached and unmapped,
5663 * undo the VM accounting.
5666 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5667 vma->vm_mm->pinned_vm -= mmap_locked;
5668 free_uid(mmap_user);
5671 ring_buffer_put(rb); /* could be last */
5674 static const struct vm_operations_struct perf_mmap_vmops = {
5675 .open = perf_mmap_open,
5676 .close = perf_mmap_close, /* non mergable */
5677 .fault = perf_mmap_fault,
5678 .page_mkwrite = perf_mmap_fault,
5681 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5683 struct perf_event *event = file->private_data;
5684 unsigned long user_locked, user_lock_limit;
5685 struct user_struct *user = current_user();
5686 unsigned long locked, lock_limit;
5687 struct ring_buffer *rb = NULL;
5688 unsigned long vma_size;
5689 unsigned long nr_pages;
5690 long user_extra = 0, extra = 0;
5691 int ret = 0, flags = 0;
5694 * Don't allow mmap() of inherited per-task counters. This would
5695 * create a performance issue due to all children writing to the
5698 if (event->cpu == -1 && event->attr.inherit)
5701 if (!(vma->vm_flags & VM_SHARED))
5704 vma_size = vma->vm_end - vma->vm_start;
5706 if (vma->vm_pgoff == 0) {
5707 nr_pages = (vma_size / PAGE_SIZE) - 1;
5710 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5711 * mapped, all subsequent mappings should have the same size
5712 * and offset. Must be above the normal perf buffer.
5714 u64 aux_offset, aux_size;
5719 nr_pages = vma_size / PAGE_SIZE;
5721 mutex_lock(&event->mmap_mutex);
5728 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5729 aux_size = READ_ONCE(rb->user_page->aux_size);
5731 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5734 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5737 /* already mapped with a different offset */
5738 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5741 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5744 /* already mapped with a different size */
5745 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5748 if (!is_power_of_2(nr_pages))
5751 if (!atomic_inc_not_zero(&rb->mmap_count))
5754 if (rb_has_aux(rb)) {
5755 atomic_inc(&rb->aux_mmap_count);
5760 atomic_set(&rb->aux_mmap_count, 1);
5761 user_extra = nr_pages;
5767 * If we have rb pages ensure they're a power-of-two number, so we
5768 * can do bitmasks instead of modulo.
5770 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5773 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5776 WARN_ON_ONCE(event->ctx->parent_ctx);
5778 mutex_lock(&event->mmap_mutex);
5780 if (event->rb->nr_pages != nr_pages) {
5785 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5787 * Raced against perf_mmap_close(); remove the
5788 * event and try again.
5790 ring_buffer_attach(event, NULL);
5791 mutex_unlock(&event->mmap_mutex);
5798 user_extra = nr_pages + 1;
5801 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5804 * Increase the limit linearly with more CPUs:
5806 user_lock_limit *= num_online_cpus();
5808 user_locked = atomic_long_read(&user->locked_vm);
5811 * sysctl_perf_event_mlock may have changed, so that
5812 * user->locked_vm > user_lock_limit
5814 if (user_locked > user_lock_limit)
5815 user_locked = user_lock_limit;
5816 user_locked += user_extra;
5818 if (user_locked > user_lock_limit)
5819 extra = user_locked - user_lock_limit;
5821 lock_limit = rlimit(RLIMIT_MEMLOCK);
5822 lock_limit >>= PAGE_SHIFT;
5823 locked = vma->vm_mm->pinned_vm + extra;
5825 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5826 !capable(CAP_IPC_LOCK)) {
5831 WARN_ON(!rb && event->rb);
5833 if (vma->vm_flags & VM_WRITE)
5834 flags |= RING_BUFFER_WRITABLE;
5837 rb = rb_alloc(nr_pages,
5838 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5846 atomic_set(&rb->mmap_count, 1);
5847 rb->mmap_user = get_current_user();
5848 rb->mmap_locked = extra;
5850 ring_buffer_attach(event, rb);
5852 perf_event_init_userpage(event);
5853 perf_event_update_userpage(event);
5855 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5856 event->attr.aux_watermark, flags);
5858 rb->aux_mmap_locked = extra;
5863 atomic_long_add(user_extra, &user->locked_vm);
5864 vma->vm_mm->pinned_vm += extra;
5866 atomic_inc(&event->mmap_count);
5868 atomic_dec(&rb->mmap_count);
5871 mutex_unlock(&event->mmap_mutex);
5874 * Since pinned accounting is per vm we cannot allow fork() to copy our
5877 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5878 vma->vm_ops = &perf_mmap_vmops;
5880 if (event->pmu->event_mapped)
5881 event->pmu->event_mapped(event, vma->vm_mm);
5886 static int perf_fasync(int fd, struct file *filp, int on)
5888 struct inode *inode = file_inode(filp);
5889 struct perf_event *event = filp->private_data;
5893 retval = fasync_helper(fd, filp, on, &event->fasync);
5894 inode_unlock(inode);
5902 static const struct file_operations perf_fops = {
5903 .llseek = no_llseek,
5904 .release = perf_release,
5907 .unlocked_ioctl = perf_ioctl,
5908 .compat_ioctl = perf_compat_ioctl,
5910 .fasync = perf_fasync,
5916 * If there's data, ensure we set the poll() state and publish everything
5917 * to user-space before waking everybody up.
5920 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5922 /* only the parent has fasync state */
5924 event = event->parent;
5925 return &event->fasync;
5928 void perf_event_wakeup(struct perf_event *event)
5930 ring_buffer_wakeup(event);
5932 if (event->pending_kill) {
5933 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5934 event->pending_kill = 0;
5938 static void perf_pending_event_disable(struct perf_event *event)
5940 int cpu = READ_ONCE(event->pending_disable);
5945 if (cpu == smp_processor_id()) {
5946 WRITE_ONCE(event->pending_disable, -1);
5947 perf_event_disable_local(event);
5954 * perf_event_disable_inatomic()
5955 * @pending_disable = CPU-A;
5959 * @pending_disable = -1;
5962 * perf_event_disable_inatomic()
5963 * @pending_disable = CPU-B;
5964 * irq_work_queue(); // FAILS
5967 * perf_pending_event()
5969 * But the event runs on CPU-B and wants disabling there.
5971 irq_work_queue_on(&event->pending, cpu);
5974 static void perf_pending_event(struct irq_work *entry)
5976 struct perf_event *event = container_of(entry, struct perf_event, pending);
5979 rctx = perf_swevent_get_recursion_context();
5981 * If we 'fail' here, that's OK, it means recursion is already disabled
5982 * and we won't recurse 'further'.
5985 perf_pending_event_disable(event);
5987 if (event->pending_wakeup) {
5988 event->pending_wakeup = 0;
5989 perf_event_wakeup(event);
5993 perf_swevent_put_recursion_context(rctx);
5997 * We assume there is only KVM supporting the callbacks.
5998 * Later on, we might change it to a list if there is
5999 * another virtualization implementation supporting the callbacks.
6001 struct perf_guest_info_callbacks *perf_guest_cbs;
6003 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6005 perf_guest_cbs = cbs;
6008 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6010 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6012 perf_guest_cbs = NULL;
6015 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6018 perf_output_sample_regs(struct perf_output_handle *handle,
6019 struct pt_regs *regs, u64 mask)
6022 DECLARE_BITMAP(_mask, 64);
6024 bitmap_from_u64(_mask, mask);
6025 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6028 val = perf_reg_value(regs, bit);
6029 perf_output_put(handle, val);
6033 static void perf_sample_regs_user(struct perf_regs *regs_user,
6034 struct pt_regs *regs,
6035 struct pt_regs *regs_user_copy)
6037 if (user_mode(regs)) {
6038 regs_user->abi = perf_reg_abi(current);
6039 regs_user->regs = regs;
6040 } else if (!(current->flags & PF_KTHREAD)) {
6041 perf_get_regs_user(regs_user, regs, regs_user_copy);
6043 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6044 regs_user->regs = NULL;
6048 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6049 struct pt_regs *regs)
6051 regs_intr->regs = regs;
6052 regs_intr->abi = perf_reg_abi(current);
6057 * Get remaining task size from user stack pointer.
6059 * It'd be better to take stack vma map and limit this more
6060 * precisly, but there's no way to get it safely under interrupt,
6061 * so using TASK_SIZE as limit.
6063 static u64 perf_ustack_task_size(struct pt_regs *regs)
6065 unsigned long addr = perf_user_stack_pointer(regs);
6067 if (!addr || addr >= TASK_SIZE)
6070 return TASK_SIZE - addr;
6074 perf_sample_ustack_size(u16 stack_size, u16 header_size,
6075 struct pt_regs *regs)
6079 /* No regs, no stack pointer, no dump. */
6084 * Check if we fit in with the requested stack size into the:
6086 * If we don't, we limit the size to the TASK_SIZE.
6088 * - remaining sample size
6089 * If we don't, we customize the stack size to
6090 * fit in to the remaining sample size.
6093 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6094 stack_size = min(stack_size, (u16) task_size);
6096 /* Current header size plus static size and dynamic size. */
6097 header_size += 2 * sizeof(u64);
6099 /* Do we fit in with the current stack dump size? */
6100 if ((u16) (header_size + stack_size) < header_size) {
6102 * If we overflow the maximum size for the sample,
6103 * we customize the stack dump size to fit in.
6105 stack_size = USHRT_MAX - header_size - sizeof(u64);
6106 stack_size = round_up(stack_size, sizeof(u64));
6113 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6114 struct pt_regs *regs)
6116 /* Case of a kernel thread, nothing to dump */
6119 perf_output_put(handle, size);
6129 * - the size requested by user or the best one we can fit
6130 * in to the sample max size
6132 * - user stack dump data
6134 * - the actual dumped size
6138 perf_output_put(handle, dump_size);
6141 sp = perf_user_stack_pointer(regs);
6144 rem = __output_copy_user(handle, (void *) sp, dump_size);
6146 dyn_size = dump_size - rem;
6148 perf_output_skip(handle, rem);
6151 perf_output_put(handle, dyn_size);
6155 static void __perf_event_header__init_id(struct perf_event_header *header,
6156 struct perf_sample_data *data,
6157 struct perf_event *event)
6159 u64 sample_type = event->attr.sample_type;
6161 data->type = sample_type;
6162 header->size += event->id_header_size;
6164 if (sample_type & PERF_SAMPLE_TID) {
6165 /* namespace issues */
6166 data->tid_entry.pid = perf_event_pid(event, current);
6167 data->tid_entry.tid = perf_event_tid(event, current);
6170 if (sample_type & PERF_SAMPLE_TIME)
6171 data->time = perf_event_clock(event);
6173 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6174 data->id = primary_event_id(event);
6176 if (sample_type & PERF_SAMPLE_STREAM_ID)
6177 data->stream_id = event->id;
6179 if (sample_type & PERF_SAMPLE_CPU) {
6180 data->cpu_entry.cpu = raw_smp_processor_id();
6181 data->cpu_entry.reserved = 0;
6185 void perf_event_header__init_id(struct perf_event_header *header,
6186 struct perf_sample_data *data,
6187 struct perf_event *event)
6189 if (event->attr.sample_id_all)
6190 __perf_event_header__init_id(header, data, event);
6193 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6194 struct perf_sample_data *data)
6196 u64 sample_type = data->type;
6198 if (sample_type & PERF_SAMPLE_TID)
6199 perf_output_put(handle, data->tid_entry);
6201 if (sample_type & PERF_SAMPLE_TIME)
6202 perf_output_put(handle, data->time);
6204 if (sample_type & PERF_SAMPLE_ID)
6205 perf_output_put(handle, data->id);
6207 if (sample_type & PERF_SAMPLE_STREAM_ID)
6208 perf_output_put(handle, data->stream_id);
6210 if (sample_type & PERF_SAMPLE_CPU)
6211 perf_output_put(handle, data->cpu_entry);
6213 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6214 perf_output_put(handle, data->id);
6217 void perf_event__output_id_sample(struct perf_event *event,
6218 struct perf_output_handle *handle,
6219 struct perf_sample_data *sample)
6221 if (event->attr.sample_id_all)
6222 __perf_event__output_id_sample(handle, sample);
6225 static void perf_output_read_one(struct perf_output_handle *handle,
6226 struct perf_event *event,
6227 u64 enabled, u64 running)
6229 u64 read_format = event->attr.read_format;
6233 values[n++] = perf_event_count(event);
6234 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6235 values[n++] = enabled +
6236 atomic64_read(&event->child_total_time_enabled);
6238 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6239 values[n++] = running +
6240 atomic64_read(&event->child_total_time_running);
6242 if (read_format & PERF_FORMAT_ID)
6243 values[n++] = primary_event_id(event);
6244 if (read_format & PERF_FORMAT_LOST)
6245 values[n++] = atomic64_read(&event->lost_samples);
6247 __output_copy(handle, values, n * sizeof(u64));
6250 static void perf_output_read_group(struct perf_output_handle *handle,
6251 struct perf_event *event,
6252 u64 enabled, u64 running)
6254 struct perf_event *leader = event->group_leader, *sub;
6255 u64 read_format = event->attr.read_format;
6259 values[n++] = 1 + leader->nr_siblings;
6261 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6262 values[n++] = enabled;
6264 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6265 values[n++] = running;
6267 if ((leader != event) &&
6268 (leader->state == PERF_EVENT_STATE_ACTIVE))
6269 leader->pmu->read(leader);
6271 values[n++] = perf_event_count(leader);
6272 if (read_format & PERF_FORMAT_ID)
6273 values[n++] = primary_event_id(leader);
6274 if (read_format & PERF_FORMAT_LOST)
6275 values[n++] = atomic64_read(&leader->lost_samples);
6277 __output_copy(handle, values, n * sizeof(u64));
6279 for_each_sibling_event(sub, leader) {
6282 if ((sub != event) &&
6283 (sub->state == PERF_EVENT_STATE_ACTIVE))
6284 sub->pmu->read(sub);
6286 values[n++] = perf_event_count(sub);
6287 if (read_format & PERF_FORMAT_ID)
6288 values[n++] = primary_event_id(sub);
6289 if (read_format & PERF_FORMAT_LOST)
6290 values[n++] = atomic64_read(&sub->lost_samples);
6292 __output_copy(handle, values, n * sizeof(u64));
6296 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6297 PERF_FORMAT_TOTAL_TIME_RUNNING)
6300 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6302 * The problem is that its both hard and excessively expensive to iterate the
6303 * child list, not to mention that its impossible to IPI the children running
6304 * on another CPU, from interrupt/NMI context.
6306 static void perf_output_read(struct perf_output_handle *handle,
6307 struct perf_event *event)
6309 u64 enabled = 0, running = 0, now;
6310 u64 read_format = event->attr.read_format;
6313 * compute total_time_enabled, total_time_running
6314 * based on snapshot values taken when the event
6315 * was last scheduled in.
6317 * we cannot simply called update_context_time()
6318 * because of locking issue as we are called in
6321 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6322 calc_timer_values(event, &now, &enabled, &running);
6324 if (event->attr.read_format & PERF_FORMAT_GROUP)
6325 perf_output_read_group(handle, event, enabled, running);
6327 perf_output_read_one(handle, event, enabled, running);
6330 void perf_output_sample(struct perf_output_handle *handle,
6331 struct perf_event_header *header,
6332 struct perf_sample_data *data,
6333 struct perf_event *event)
6335 u64 sample_type = data->type;
6337 perf_output_put(handle, *header);
6339 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6340 perf_output_put(handle, data->id);
6342 if (sample_type & PERF_SAMPLE_IP)
6343 perf_output_put(handle, data->ip);
6345 if (sample_type & PERF_SAMPLE_TID)
6346 perf_output_put(handle, data->tid_entry);
6348 if (sample_type & PERF_SAMPLE_TIME)
6349 perf_output_put(handle, data->time);
6351 if (sample_type & PERF_SAMPLE_ADDR)
6352 perf_output_put(handle, data->addr);
6354 if (sample_type & PERF_SAMPLE_ID)
6355 perf_output_put(handle, data->id);
6357 if (sample_type & PERF_SAMPLE_STREAM_ID)
6358 perf_output_put(handle, data->stream_id);
6360 if (sample_type & PERF_SAMPLE_CPU)
6361 perf_output_put(handle, data->cpu_entry);
6363 if (sample_type & PERF_SAMPLE_PERIOD)
6364 perf_output_put(handle, data->period);
6366 if (sample_type & PERF_SAMPLE_READ)
6367 perf_output_read(handle, event);
6369 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6372 size += data->callchain->nr;
6373 size *= sizeof(u64);
6374 __output_copy(handle, data->callchain, size);
6377 if (sample_type & PERF_SAMPLE_RAW) {
6378 struct perf_raw_record *raw = data->raw;
6381 struct perf_raw_frag *frag = &raw->frag;
6383 perf_output_put(handle, raw->size);
6386 __output_custom(handle, frag->copy,
6387 frag->data, frag->size);
6389 __output_copy(handle, frag->data,
6392 if (perf_raw_frag_last(frag))
6397 __output_skip(handle, NULL, frag->pad);
6403 .size = sizeof(u32),
6406 perf_output_put(handle, raw);
6410 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6411 if (data->br_stack) {
6414 size = data->br_stack->nr
6415 * sizeof(struct perf_branch_entry);
6417 perf_output_put(handle, data->br_stack->nr);
6418 perf_output_copy(handle, data->br_stack->entries, size);
6421 * we always store at least the value of nr
6424 perf_output_put(handle, nr);
6428 if (sample_type & PERF_SAMPLE_REGS_USER) {
6429 u64 abi = data->regs_user.abi;
6432 * If there are no regs to dump, notice it through
6433 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6435 perf_output_put(handle, abi);
6438 u64 mask = event->attr.sample_regs_user;
6439 perf_output_sample_regs(handle,
6440 data->regs_user.regs,
6445 if (sample_type & PERF_SAMPLE_STACK_USER) {
6446 perf_output_sample_ustack(handle,
6447 data->stack_user_size,
6448 data->regs_user.regs);
6451 if (sample_type & PERF_SAMPLE_WEIGHT)
6452 perf_output_put(handle, data->weight);
6454 if (sample_type & PERF_SAMPLE_DATA_SRC)
6455 perf_output_put(handle, data->data_src.val);
6457 if (sample_type & PERF_SAMPLE_TRANSACTION)
6458 perf_output_put(handle, data->txn);
6460 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6461 u64 abi = data->regs_intr.abi;
6463 * If there are no regs to dump, notice it through
6464 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6466 perf_output_put(handle, abi);
6469 u64 mask = event->attr.sample_regs_intr;
6471 perf_output_sample_regs(handle,
6472 data->regs_intr.regs,
6477 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6478 perf_output_put(handle, data->phys_addr);
6480 if (!event->attr.watermark) {
6481 int wakeup_events = event->attr.wakeup_events;
6483 if (wakeup_events) {
6484 struct ring_buffer *rb = handle->rb;
6485 int events = local_inc_return(&rb->events);
6487 if (events >= wakeup_events) {
6488 local_sub(wakeup_events, &rb->events);
6489 local_inc(&rb->wakeup);
6495 static u64 perf_virt_to_phys(u64 virt)
6502 if (virt >= TASK_SIZE) {
6503 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6504 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6505 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6506 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6509 * Walking the pages tables for user address.
6510 * Interrupts are disabled, so it prevents any tear down
6511 * of the page tables.
6512 * Try IRQ-safe __get_user_pages_fast first.
6513 * If failed, leave phys_addr as 0.
6515 if (current->mm != NULL) {
6518 pagefault_disable();
6519 if (__get_user_pages_fast(virt, 1, 0, &p) == 1) {
6520 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6530 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6532 struct perf_callchain_entry *
6533 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6535 bool kernel = !event->attr.exclude_callchain_kernel;
6536 bool user = !event->attr.exclude_callchain_user;
6537 /* Disallow cross-task user callchains. */
6538 bool crosstask = event->ctx->task && event->ctx->task != current;
6539 const u32 max_stack = event->attr.sample_max_stack;
6540 struct perf_callchain_entry *callchain;
6542 if (!kernel && !user)
6543 return &__empty_callchain;
6545 callchain = get_perf_callchain(regs, 0, kernel, user,
6546 max_stack, crosstask, true);
6547 return callchain ?: &__empty_callchain;
6550 void perf_prepare_sample(struct perf_event_header *header,
6551 struct perf_sample_data *data,
6552 struct perf_event *event,
6553 struct pt_regs *regs)
6555 u64 sample_type = event->attr.sample_type;
6557 header->type = PERF_RECORD_SAMPLE;
6558 header->size = sizeof(*header) + event->header_size;
6561 header->misc |= perf_misc_flags(regs);
6563 __perf_event_header__init_id(header, data, event);
6565 if (sample_type & PERF_SAMPLE_IP)
6566 data->ip = perf_instruction_pointer(regs);
6568 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6571 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6572 data->callchain = perf_callchain(event, regs);
6574 size += data->callchain->nr;
6576 header->size += size * sizeof(u64);
6579 if (sample_type & PERF_SAMPLE_RAW) {
6580 struct perf_raw_record *raw = data->raw;
6584 struct perf_raw_frag *frag = &raw->frag;
6589 if (perf_raw_frag_last(frag))
6594 size = round_up(sum + sizeof(u32), sizeof(u64));
6595 raw->size = size - sizeof(u32);
6596 frag->pad = raw->size - sum;
6601 header->size += size;
6604 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6605 int size = sizeof(u64); /* nr */
6606 if (data->br_stack) {
6607 size += data->br_stack->nr
6608 * sizeof(struct perf_branch_entry);
6610 header->size += size;
6613 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6614 perf_sample_regs_user(&data->regs_user, regs,
6615 &data->regs_user_copy);
6617 if (sample_type & PERF_SAMPLE_REGS_USER) {
6618 /* regs dump ABI info */
6619 int size = sizeof(u64);
6621 if (data->regs_user.regs) {
6622 u64 mask = event->attr.sample_regs_user;
6623 size += hweight64(mask) * sizeof(u64);
6626 header->size += size;
6629 if (sample_type & PERF_SAMPLE_STACK_USER) {
6631 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6632 * processed as the last one or have additional check added
6633 * in case new sample type is added, because we could eat
6634 * up the rest of the sample size.
6636 u16 stack_size = event->attr.sample_stack_user;
6637 u16 size = sizeof(u64);
6639 stack_size = perf_sample_ustack_size(stack_size, header->size,
6640 data->regs_user.regs);
6643 * If there is something to dump, add space for the dump
6644 * itself and for the field that tells the dynamic size,
6645 * which is how many have been actually dumped.
6648 size += sizeof(u64) + stack_size;
6650 data->stack_user_size = stack_size;
6651 header->size += size;
6654 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6655 /* regs dump ABI info */
6656 int size = sizeof(u64);
6658 perf_sample_regs_intr(&data->regs_intr, regs);
6660 if (data->regs_intr.regs) {
6661 u64 mask = event->attr.sample_regs_intr;
6663 size += hweight64(mask) * sizeof(u64);
6666 header->size += size;
6669 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6670 data->phys_addr = perf_virt_to_phys(data->addr);
6673 static __always_inline void
6674 __perf_event_output(struct perf_event *event,
6675 struct perf_sample_data *data,
6676 struct pt_regs *regs,
6677 int (*output_begin)(struct perf_output_handle *,
6678 struct perf_event *,
6681 struct perf_output_handle handle;
6682 struct perf_event_header header;
6684 /* protect the callchain buffers */
6687 perf_prepare_sample(&header, data, event, regs);
6689 if (output_begin(&handle, event, header.size))
6692 perf_output_sample(&handle, &header, data, event);
6694 perf_output_end(&handle);
6701 perf_event_output_forward(struct perf_event *event,
6702 struct perf_sample_data *data,
6703 struct pt_regs *regs)
6705 __perf_event_output(event, data, regs, perf_output_begin_forward);
6709 perf_event_output_backward(struct perf_event *event,
6710 struct perf_sample_data *data,
6711 struct pt_regs *regs)
6713 __perf_event_output(event, data, regs, perf_output_begin_backward);
6717 perf_event_output(struct perf_event *event,
6718 struct perf_sample_data *data,
6719 struct pt_regs *regs)
6721 __perf_event_output(event, data, regs, perf_output_begin);
6728 struct perf_read_event {
6729 struct perf_event_header header;
6736 perf_event_read_event(struct perf_event *event,
6737 struct task_struct *task)
6739 struct perf_output_handle handle;
6740 struct perf_sample_data sample;
6741 struct perf_read_event read_event = {
6743 .type = PERF_RECORD_READ,
6745 .size = sizeof(read_event) + event->read_size,
6747 .pid = perf_event_pid(event, task),
6748 .tid = perf_event_tid(event, task),
6752 perf_event_header__init_id(&read_event.header, &sample, event);
6753 ret = perf_output_begin(&handle, event, read_event.header.size);
6757 perf_output_put(&handle, read_event);
6758 perf_output_read(&handle, event);
6759 perf_event__output_id_sample(event, &handle, &sample);
6761 perf_output_end(&handle);
6764 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6767 perf_iterate_ctx(struct perf_event_context *ctx,
6768 perf_iterate_f output,
6769 void *data, bool all)
6771 struct perf_event *event;
6773 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6775 if (event->state < PERF_EVENT_STATE_INACTIVE)
6777 if (!event_filter_match(event))
6781 output(event, data);
6785 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6787 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6788 struct perf_event *event;
6790 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6792 * Skip events that are not fully formed yet; ensure that
6793 * if we observe event->ctx, both event and ctx will be
6794 * complete enough. See perf_install_in_context().
6796 if (!smp_load_acquire(&event->ctx))
6799 if (event->state < PERF_EVENT_STATE_INACTIVE)
6801 if (!event_filter_match(event))
6803 output(event, data);
6808 * Iterate all events that need to receive side-band events.
6810 * For new callers; ensure that account_pmu_sb_event() includes
6811 * your event, otherwise it might not get delivered.
6814 perf_iterate_sb(perf_iterate_f output, void *data,
6815 struct perf_event_context *task_ctx)
6817 struct perf_event_context *ctx;
6824 * If we have task_ctx != NULL we only notify the task context itself.
6825 * The task_ctx is set only for EXIT events before releasing task
6829 perf_iterate_ctx(task_ctx, output, data, false);
6833 perf_iterate_sb_cpu(output, data);
6835 for_each_task_context_nr(ctxn) {
6836 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6838 perf_iterate_ctx(ctx, output, data, false);
6846 * Clear all file-based filters at exec, they'll have to be
6847 * re-instated when/if these objects are mmapped again.
6849 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6851 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6852 struct perf_addr_filter *filter;
6853 unsigned int restart = 0, count = 0;
6854 unsigned long flags;
6856 if (!has_addr_filter(event))
6859 raw_spin_lock_irqsave(&ifh->lock, flags);
6860 list_for_each_entry(filter, &ifh->list, entry) {
6861 if (filter->path.dentry) {
6862 event->addr_filter_ranges[count].start = 0;
6863 event->addr_filter_ranges[count].size = 0;
6871 event->addr_filters_gen++;
6872 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6875 perf_event_stop(event, 1);
6878 void perf_event_exec(void)
6880 struct perf_event_context *ctx;
6884 for_each_task_context_nr(ctxn) {
6885 ctx = current->perf_event_ctxp[ctxn];
6889 perf_event_enable_on_exec(ctxn);
6891 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6897 struct remote_output {
6898 struct ring_buffer *rb;
6902 static void __perf_event_output_stop(struct perf_event *event, void *data)
6904 struct perf_event *parent = event->parent;
6905 struct remote_output *ro = data;
6906 struct ring_buffer *rb = ro->rb;
6907 struct stop_event_data sd = {
6911 if (!has_aux(event))
6918 * In case of inheritance, it will be the parent that links to the
6919 * ring-buffer, but it will be the child that's actually using it.
6921 * We are using event::rb to determine if the event should be stopped,
6922 * however this may race with ring_buffer_attach() (through set_output),
6923 * which will make us skip the event that actually needs to be stopped.
6924 * So ring_buffer_attach() has to stop an aux event before re-assigning
6927 if (rcu_dereference(parent->rb) == rb)
6928 ro->err = __perf_event_stop(&sd);
6931 static int __perf_pmu_output_stop(void *info)
6933 struct perf_event *event = info;
6934 struct pmu *pmu = event->ctx->pmu;
6935 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6936 struct remote_output ro = {
6941 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6942 if (cpuctx->task_ctx)
6943 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6950 static void perf_pmu_output_stop(struct perf_event *event)
6952 struct perf_event *iter;
6957 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6959 * For per-CPU events, we need to make sure that neither they
6960 * nor their children are running; for cpu==-1 events it's
6961 * sufficient to stop the event itself if it's active, since
6962 * it can't have children.
6966 cpu = READ_ONCE(iter->oncpu);
6971 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6972 if (err == -EAGAIN) {
6981 * task tracking -- fork/exit
6983 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6986 struct perf_task_event {
6987 struct task_struct *task;
6988 struct perf_event_context *task_ctx;
6991 struct perf_event_header header;
7001 static int perf_event_task_match(struct perf_event *event)
7003 return event->attr.comm || event->attr.mmap ||
7004 event->attr.mmap2 || event->attr.mmap_data ||
7008 static void perf_event_task_output(struct perf_event *event,
7011 struct perf_task_event *task_event = data;
7012 struct perf_output_handle handle;
7013 struct perf_sample_data sample;
7014 struct task_struct *task = task_event->task;
7015 int ret, size = task_event->event_id.header.size;
7017 if (!perf_event_task_match(event))
7020 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
7022 ret = perf_output_begin(&handle, event,
7023 task_event->event_id.header.size);
7027 task_event->event_id.pid = perf_event_pid(event, task);
7028 task_event->event_id.tid = perf_event_tid(event, task);
7030 if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
7031 task_event->event_id.ppid = perf_event_pid(event,
7033 task_event->event_id.ptid = perf_event_pid(event,
7035 } else { /* PERF_RECORD_FORK */
7036 task_event->event_id.ppid = perf_event_pid(event, current);
7037 task_event->event_id.ptid = perf_event_tid(event, current);
7040 task_event->event_id.time = perf_event_clock(event);
7042 perf_output_put(&handle, task_event->event_id);
7044 perf_event__output_id_sample(event, &handle, &sample);
7046 perf_output_end(&handle);
7048 task_event->event_id.header.size = size;
7051 static void perf_event_task(struct task_struct *task,
7052 struct perf_event_context *task_ctx,
7055 struct perf_task_event task_event;
7057 if (!atomic_read(&nr_comm_events) &&
7058 !atomic_read(&nr_mmap_events) &&
7059 !atomic_read(&nr_task_events))
7062 task_event = (struct perf_task_event){
7064 .task_ctx = task_ctx,
7067 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7069 .size = sizeof(task_event.event_id),
7079 perf_iterate_sb(perf_event_task_output,
7084 void perf_event_fork(struct task_struct *task)
7086 perf_event_task(task, NULL, 1);
7087 perf_event_namespaces(task);
7094 struct perf_comm_event {
7095 struct task_struct *task;
7100 struct perf_event_header header;
7107 static int perf_event_comm_match(struct perf_event *event)
7109 return event->attr.comm;
7112 static void perf_event_comm_output(struct perf_event *event,
7115 struct perf_comm_event *comm_event = data;
7116 struct perf_output_handle handle;
7117 struct perf_sample_data sample;
7118 int size = comm_event->event_id.header.size;
7121 if (!perf_event_comm_match(event))
7124 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7125 ret = perf_output_begin(&handle, event,
7126 comm_event->event_id.header.size);
7131 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7132 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7134 perf_output_put(&handle, comm_event->event_id);
7135 __output_copy(&handle, comm_event->comm,
7136 comm_event->comm_size);
7138 perf_event__output_id_sample(event, &handle, &sample);
7140 perf_output_end(&handle);
7142 comm_event->event_id.header.size = size;
7145 static void perf_event_comm_event(struct perf_comm_event *comm_event)
7147 char comm[TASK_COMM_LEN];
7150 memset(comm, 0, sizeof(comm));
7151 strlcpy(comm, comm_event->task->comm, sizeof(comm));
7152 size = ALIGN(strlen(comm)+1, sizeof(u64));
7154 comm_event->comm = comm;
7155 comm_event->comm_size = size;
7157 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7159 perf_iterate_sb(perf_event_comm_output,
7164 void perf_event_comm(struct task_struct *task, bool exec)
7166 struct perf_comm_event comm_event;
7168 if (!atomic_read(&nr_comm_events))
7171 comm_event = (struct perf_comm_event){
7177 .type = PERF_RECORD_COMM,
7178 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7186 perf_event_comm_event(&comm_event);
7190 * namespaces tracking
7193 struct perf_namespaces_event {
7194 struct task_struct *task;
7197 struct perf_event_header header;
7202 struct perf_ns_link_info link_info[NR_NAMESPACES];
7206 static int perf_event_namespaces_match(struct perf_event *event)
7208 return event->attr.namespaces;
7211 static void perf_event_namespaces_output(struct perf_event *event,
7214 struct perf_namespaces_event *namespaces_event = data;
7215 struct perf_output_handle handle;
7216 struct perf_sample_data sample;
7217 u16 header_size = namespaces_event->event_id.header.size;
7220 if (!perf_event_namespaces_match(event))
7223 perf_event_header__init_id(&namespaces_event->event_id.header,
7225 ret = perf_output_begin(&handle, event,
7226 namespaces_event->event_id.header.size);
7230 namespaces_event->event_id.pid = perf_event_pid(event,
7231 namespaces_event->task);
7232 namespaces_event->event_id.tid = perf_event_tid(event,
7233 namespaces_event->task);
7235 perf_output_put(&handle, namespaces_event->event_id);
7237 perf_event__output_id_sample(event, &handle, &sample);
7239 perf_output_end(&handle);
7241 namespaces_event->event_id.header.size = header_size;
7244 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7245 struct task_struct *task,
7246 const struct proc_ns_operations *ns_ops)
7248 struct path ns_path;
7249 struct inode *ns_inode;
7252 error = ns_get_path(&ns_path, task, ns_ops);
7254 ns_inode = ns_path.dentry->d_inode;
7255 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7256 ns_link_info->ino = ns_inode->i_ino;
7261 void perf_event_namespaces(struct task_struct *task)
7263 struct perf_namespaces_event namespaces_event;
7264 struct perf_ns_link_info *ns_link_info;
7266 if (!atomic_read(&nr_namespaces_events))
7269 namespaces_event = (struct perf_namespaces_event){
7273 .type = PERF_RECORD_NAMESPACES,
7275 .size = sizeof(namespaces_event.event_id),
7279 .nr_namespaces = NR_NAMESPACES,
7280 /* .link_info[NR_NAMESPACES] */
7284 ns_link_info = namespaces_event.event_id.link_info;
7286 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7287 task, &mntns_operations);
7289 #ifdef CONFIG_USER_NS
7290 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7291 task, &userns_operations);
7293 #ifdef CONFIG_NET_NS
7294 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7295 task, &netns_operations);
7297 #ifdef CONFIG_UTS_NS
7298 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7299 task, &utsns_operations);
7301 #ifdef CONFIG_IPC_NS
7302 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7303 task, &ipcns_operations);
7305 #ifdef CONFIG_PID_NS
7306 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7307 task, &pidns_operations);
7309 #ifdef CONFIG_CGROUPS
7310 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7311 task, &cgroupns_operations);
7314 perf_iterate_sb(perf_event_namespaces_output,
7323 struct perf_mmap_event {
7324 struct vm_area_struct *vma;
7326 const char *file_name;
7334 struct perf_event_header header;
7344 static int perf_event_mmap_match(struct perf_event *event,
7347 struct perf_mmap_event *mmap_event = data;
7348 struct vm_area_struct *vma = mmap_event->vma;
7349 int executable = vma->vm_flags & VM_EXEC;
7351 return (!executable && event->attr.mmap_data) ||
7352 (executable && (event->attr.mmap || event->attr.mmap2));
7355 static void perf_event_mmap_output(struct perf_event *event,
7358 struct perf_mmap_event *mmap_event = data;
7359 struct perf_output_handle handle;
7360 struct perf_sample_data sample;
7361 int size = mmap_event->event_id.header.size;
7362 u32 type = mmap_event->event_id.header.type;
7365 if (!perf_event_mmap_match(event, data))
7368 if (event->attr.mmap2) {
7369 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7370 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7371 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7372 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7373 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7374 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7375 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7378 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7379 ret = perf_output_begin(&handle, event,
7380 mmap_event->event_id.header.size);
7384 mmap_event->event_id.pid = perf_event_pid(event, current);
7385 mmap_event->event_id.tid = perf_event_tid(event, current);
7387 perf_output_put(&handle, mmap_event->event_id);
7389 if (event->attr.mmap2) {
7390 perf_output_put(&handle, mmap_event->maj);
7391 perf_output_put(&handle, mmap_event->min);
7392 perf_output_put(&handle, mmap_event->ino);
7393 perf_output_put(&handle, mmap_event->ino_generation);
7394 perf_output_put(&handle, mmap_event->prot);
7395 perf_output_put(&handle, mmap_event->flags);
7398 __output_copy(&handle, mmap_event->file_name,
7399 mmap_event->file_size);
7401 perf_event__output_id_sample(event, &handle, &sample);
7403 perf_output_end(&handle);
7405 mmap_event->event_id.header.size = size;
7406 mmap_event->event_id.header.type = type;
7409 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7411 struct vm_area_struct *vma = mmap_event->vma;
7412 struct file *file = vma->vm_file;
7413 int maj = 0, min = 0;
7414 u64 ino = 0, gen = 0;
7415 u32 prot = 0, flags = 0;
7421 if (vma->vm_flags & VM_READ)
7423 if (vma->vm_flags & VM_WRITE)
7425 if (vma->vm_flags & VM_EXEC)
7428 if (vma->vm_flags & VM_MAYSHARE)
7431 flags = MAP_PRIVATE;
7433 if (vma->vm_flags & VM_DENYWRITE)
7434 flags |= MAP_DENYWRITE;
7435 if (vma->vm_flags & VM_MAYEXEC)
7436 flags |= MAP_EXECUTABLE;
7437 if (vma->vm_flags & VM_LOCKED)
7438 flags |= MAP_LOCKED;
7439 if (vma->vm_flags & VM_HUGETLB)
7440 flags |= MAP_HUGETLB;
7443 struct inode *inode;
7446 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7452 * d_path() works from the end of the rb backwards, so we
7453 * need to add enough zero bytes after the string to handle
7454 * the 64bit alignment we do later.
7456 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7461 inode = file_inode(vma->vm_file);
7462 dev = inode->i_sb->s_dev;
7464 gen = inode->i_generation;
7470 if (vma->vm_ops && vma->vm_ops->name) {
7471 name = (char *) vma->vm_ops->name(vma);
7476 name = (char *)arch_vma_name(vma);
7480 if (vma->vm_start <= vma->vm_mm->start_brk &&
7481 vma->vm_end >= vma->vm_mm->brk) {
7485 if (vma->vm_start <= vma->vm_mm->start_stack &&
7486 vma->vm_end >= vma->vm_mm->start_stack) {
7496 strlcpy(tmp, name, sizeof(tmp));
7500 * Since our buffer works in 8 byte units we need to align our string
7501 * size to a multiple of 8. However, we must guarantee the tail end is
7502 * zero'd out to avoid leaking random bits to userspace.
7504 size = strlen(name)+1;
7505 while (!IS_ALIGNED(size, sizeof(u64)))
7506 name[size++] = '\0';
7508 mmap_event->file_name = name;
7509 mmap_event->file_size = size;
7510 mmap_event->maj = maj;
7511 mmap_event->min = min;
7512 mmap_event->ino = ino;
7513 mmap_event->ino_generation = gen;
7514 mmap_event->prot = prot;
7515 mmap_event->flags = flags;
7517 if (!(vma->vm_flags & VM_EXEC))
7518 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7520 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7522 perf_iterate_sb(perf_event_mmap_output,
7530 * Check whether inode and address range match filter criteria.
7532 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7533 struct file *file, unsigned long offset,
7536 /* d_inode(NULL) won't be equal to any mapped user-space file */
7537 if (!filter->path.dentry)
7540 if (d_inode(filter->path.dentry) != file_inode(file))
7543 if (filter->offset > offset + size)
7546 if (filter->offset + filter->size < offset)
7552 static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
7553 struct vm_area_struct *vma,
7554 struct perf_addr_filter_range *fr)
7556 unsigned long vma_size = vma->vm_end - vma->vm_start;
7557 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
7558 struct file *file = vma->vm_file;
7560 if (!perf_addr_filter_match(filter, file, off, vma_size))
7563 if (filter->offset < off) {
7564 fr->start = vma->vm_start;
7565 fr->size = min(vma_size, filter->size - (off - filter->offset));
7567 fr->start = vma->vm_start + filter->offset - off;
7568 fr->size = min(vma->vm_end - fr->start, filter->size);
7574 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7576 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7577 struct vm_area_struct *vma = data;
7578 struct perf_addr_filter *filter;
7579 unsigned int restart = 0, count = 0;
7580 unsigned long flags;
7582 if (!has_addr_filter(event))
7588 raw_spin_lock_irqsave(&ifh->lock, flags);
7589 list_for_each_entry(filter, &ifh->list, entry) {
7590 if (perf_addr_filter_vma_adjust(filter, vma,
7591 &event->addr_filter_ranges[count]))
7598 event->addr_filters_gen++;
7599 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7602 perf_event_stop(event, 1);
7606 * Adjust all task's events' filters to the new vma
7608 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7610 struct perf_event_context *ctx;
7614 * Data tracing isn't supported yet and as such there is no need
7615 * to keep track of anything that isn't related to executable code:
7617 if (!(vma->vm_flags & VM_EXEC))
7621 for_each_task_context_nr(ctxn) {
7622 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7626 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7631 void perf_event_mmap(struct vm_area_struct *vma)
7633 struct perf_mmap_event mmap_event;
7635 if (!atomic_read(&nr_mmap_events))
7638 mmap_event = (struct perf_mmap_event){
7644 .type = PERF_RECORD_MMAP,
7645 .misc = PERF_RECORD_MISC_USER,
7650 .start = vma->vm_start,
7651 .len = vma->vm_end - vma->vm_start,
7652 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7654 /* .maj (attr_mmap2 only) */
7655 /* .min (attr_mmap2 only) */
7656 /* .ino (attr_mmap2 only) */
7657 /* .ino_generation (attr_mmap2 only) */
7658 /* .prot (attr_mmap2 only) */
7659 /* .flags (attr_mmap2 only) */
7662 perf_addr_filters_adjust(vma);
7663 perf_event_mmap_event(&mmap_event);
7666 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7667 unsigned long size, u64 flags)
7669 struct perf_output_handle handle;
7670 struct perf_sample_data sample;
7671 struct perf_aux_event {
7672 struct perf_event_header header;
7678 .type = PERF_RECORD_AUX,
7680 .size = sizeof(rec),
7688 perf_event_header__init_id(&rec.header, &sample, event);
7689 ret = perf_output_begin(&handle, event, rec.header.size);
7694 perf_output_put(&handle, rec);
7695 perf_event__output_id_sample(event, &handle, &sample);
7697 perf_output_end(&handle);
7701 * Lost/dropped samples logging
7703 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7705 struct perf_output_handle handle;
7706 struct perf_sample_data sample;
7710 struct perf_event_header header;
7712 } lost_samples_event = {
7714 .type = PERF_RECORD_LOST_SAMPLES,
7716 .size = sizeof(lost_samples_event),
7721 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7723 ret = perf_output_begin(&handle, event,
7724 lost_samples_event.header.size);
7728 perf_output_put(&handle, lost_samples_event);
7729 perf_event__output_id_sample(event, &handle, &sample);
7730 perf_output_end(&handle);
7734 * context_switch tracking
7737 struct perf_switch_event {
7738 struct task_struct *task;
7739 struct task_struct *next_prev;
7742 struct perf_event_header header;
7748 static int perf_event_switch_match(struct perf_event *event)
7750 return event->attr.context_switch;
7753 static void perf_event_switch_output(struct perf_event *event, void *data)
7755 struct perf_switch_event *se = data;
7756 struct perf_output_handle handle;
7757 struct perf_sample_data sample;
7760 if (!perf_event_switch_match(event))
7763 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7764 if (event->ctx->task) {
7765 se->event_id.header.type = PERF_RECORD_SWITCH;
7766 se->event_id.header.size = sizeof(se->event_id.header);
7768 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7769 se->event_id.header.size = sizeof(se->event_id);
7770 se->event_id.next_prev_pid =
7771 perf_event_pid(event, se->next_prev);
7772 se->event_id.next_prev_tid =
7773 perf_event_tid(event, se->next_prev);
7776 perf_event_header__init_id(&se->event_id.header, &sample, event);
7778 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7782 if (event->ctx->task)
7783 perf_output_put(&handle, se->event_id.header);
7785 perf_output_put(&handle, se->event_id);
7787 perf_event__output_id_sample(event, &handle, &sample);
7789 perf_output_end(&handle);
7792 static void perf_event_switch(struct task_struct *task,
7793 struct task_struct *next_prev, bool sched_in)
7795 struct perf_switch_event switch_event;
7797 /* N.B. caller checks nr_switch_events != 0 */
7799 switch_event = (struct perf_switch_event){
7801 .next_prev = next_prev,
7805 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7808 /* .next_prev_pid */
7809 /* .next_prev_tid */
7813 if (!sched_in && task->state == TASK_RUNNING)
7814 switch_event.event_id.header.misc |=
7815 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
7817 perf_iterate_sb(perf_event_switch_output,
7823 * IRQ throttle logging
7826 static void perf_log_throttle(struct perf_event *event, int enable)
7828 struct perf_output_handle handle;
7829 struct perf_sample_data sample;
7833 struct perf_event_header header;
7837 } throttle_event = {
7839 .type = PERF_RECORD_THROTTLE,
7841 .size = sizeof(throttle_event),
7843 .time = perf_event_clock(event),
7844 .id = primary_event_id(event),
7845 .stream_id = event->id,
7849 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7851 perf_event_header__init_id(&throttle_event.header, &sample, event);
7853 ret = perf_output_begin(&handle, event,
7854 throttle_event.header.size);
7858 perf_output_put(&handle, throttle_event);
7859 perf_event__output_id_sample(event, &handle, &sample);
7860 perf_output_end(&handle);
7863 void perf_event_itrace_started(struct perf_event *event)
7865 event->attach_state |= PERF_ATTACH_ITRACE;
7868 static void perf_log_itrace_start(struct perf_event *event)
7870 struct perf_output_handle handle;
7871 struct perf_sample_data sample;
7872 struct perf_aux_event {
7873 struct perf_event_header header;
7880 event = event->parent;
7882 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7883 event->attach_state & PERF_ATTACH_ITRACE)
7886 rec.header.type = PERF_RECORD_ITRACE_START;
7887 rec.header.misc = 0;
7888 rec.header.size = sizeof(rec);
7889 rec.pid = perf_event_pid(event, current);
7890 rec.tid = perf_event_tid(event, current);
7892 perf_event_header__init_id(&rec.header, &sample, event);
7893 ret = perf_output_begin(&handle, event, rec.header.size);
7898 perf_output_put(&handle, rec);
7899 perf_event__output_id_sample(event, &handle, &sample);
7901 perf_output_end(&handle);
7905 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7907 struct hw_perf_event *hwc = &event->hw;
7911 seq = __this_cpu_read(perf_throttled_seq);
7912 if (seq != hwc->interrupts_seq) {
7913 hwc->interrupts_seq = seq;
7914 hwc->interrupts = 1;
7917 if (unlikely(throttle &&
7918 hwc->interrupts > max_samples_per_tick)) {
7919 __this_cpu_inc(perf_throttled_count);
7920 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7921 hwc->interrupts = MAX_INTERRUPTS;
7922 perf_log_throttle(event, 0);
7927 if (event->attr.freq) {
7928 u64 now = perf_clock();
7929 s64 delta = now - hwc->freq_time_stamp;
7931 hwc->freq_time_stamp = now;
7933 if (delta > 0 && delta < 2*TICK_NSEC)
7934 perf_adjust_period(event, delta, hwc->last_period, true);
7940 int perf_event_account_interrupt(struct perf_event *event)
7942 return __perf_event_account_interrupt(event, 1);
7946 * Generic event overflow handling, sampling.
7949 static int __perf_event_overflow(struct perf_event *event,
7950 int throttle, struct perf_sample_data *data,
7951 struct pt_regs *regs)
7953 int events = atomic_read(&event->event_limit);
7957 * Non-sampling counters might still use the PMI to fold short
7958 * hardware counters, ignore those.
7960 if (unlikely(!is_sampling_event(event)))
7963 ret = __perf_event_account_interrupt(event, throttle);
7966 * XXX event_limit might not quite work as expected on inherited
7970 event->pending_kill = POLL_IN;
7971 if (events && atomic_dec_and_test(&event->event_limit)) {
7973 event->pending_kill = POLL_HUP;
7975 perf_event_disable_inatomic(event);
7978 READ_ONCE(event->overflow_handler)(event, data, regs);
7980 if (*perf_event_fasync(event) && event->pending_kill) {
7981 event->pending_wakeup = 1;
7982 irq_work_queue(&event->pending);
7988 int perf_event_overflow(struct perf_event *event,
7989 struct perf_sample_data *data,
7990 struct pt_regs *regs)
7992 return __perf_event_overflow(event, 1, data, regs);
7996 * Generic software event infrastructure
7999 struct swevent_htable {
8000 struct swevent_hlist *swevent_hlist;
8001 struct mutex hlist_mutex;
8004 /* Recursion avoidance in each contexts */
8005 int recursion[PERF_NR_CONTEXTS];
8008 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
8011 * We directly increment event->count and keep a second value in
8012 * event->hw.period_left to count intervals. This period event
8013 * is kept in the range [-sample_period, 0] so that we can use the
8017 u64 perf_swevent_set_period(struct perf_event *event)
8019 struct hw_perf_event *hwc = &event->hw;
8020 u64 period = hwc->last_period;
8024 hwc->last_period = hwc->sample_period;
8027 old = val = local64_read(&hwc->period_left);
8031 nr = div64_u64(period + val, period);
8032 offset = nr * period;
8034 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
8040 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
8041 struct perf_sample_data *data,
8042 struct pt_regs *regs)
8044 struct hw_perf_event *hwc = &event->hw;
8048 overflow = perf_swevent_set_period(event);
8050 if (hwc->interrupts == MAX_INTERRUPTS)
8053 for (; overflow; overflow--) {
8054 if (__perf_event_overflow(event, throttle,
8057 * We inhibit the overflow from happening when
8058 * hwc->interrupts == MAX_INTERRUPTS.
8066 static void perf_swevent_event(struct perf_event *event, u64 nr,
8067 struct perf_sample_data *data,
8068 struct pt_regs *regs)
8070 struct hw_perf_event *hwc = &event->hw;
8072 local64_add(nr, &event->count);
8077 if (!is_sampling_event(event))
8080 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
8082 return perf_swevent_overflow(event, 1, data, regs);
8084 data->period = event->hw.last_period;
8086 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
8087 return perf_swevent_overflow(event, 1, data, regs);
8089 if (local64_add_negative(nr, &hwc->period_left))
8092 perf_swevent_overflow(event, 0, data, regs);
8095 static int perf_exclude_event(struct perf_event *event,
8096 struct pt_regs *regs)
8098 if (event->hw.state & PERF_HES_STOPPED)
8102 if (event->attr.exclude_user && user_mode(regs))
8105 if (event->attr.exclude_kernel && !user_mode(regs))
8112 static int perf_swevent_match(struct perf_event *event,
8113 enum perf_type_id type,
8115 struct perf_sample_data *data,
8116 struct pt_regs *regs)
8118 if (event->attr.type != type)
8121 if (event->attr.config != event_id)
8124 if (perf_exclude_event(event, regs))
8130 static inline u64 swevent_hash(u64 type, u32 event_id)
8132 u64 val = event_id | (type << 32);
8134 return hash_64(val, SWEVENT_HLIST_BITS);
8137 static inline struct hlist_head *
8138 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
8140 u64 hash = swevent_hash(type, event_id);
8142 return &hlist->heads[hash];
8145 /* For the read side: events when they trigger */
8146 static inline struct hlist_head *
8147 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
8149 struct swevent_hlist *hlist;
8151 hlist = rcu_dereference(swhash->swevent_hlist);
8155 return __find_swevent_head(hlist, type, event_id);
8158 /* For the event head insertion and removal in the hlist */
8159 static inline struct hlist_head *
8160 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
8162 struct swevent_hlist *hlist;
8163 u32 event_id = event->attr.config;
8164 u64 type = event->attr.type;
8167 * Event scheduling is always serialized against hlist allocation
8168 * and release. Which makes the protected version suitable here.
8169 * The context lock guarantees that.
8171 hlist = rcu_dereference_protected(swhash->swevent_hlist,
8172 lockdep_is_held(&event->ctx->lock));
8176 return __find_swevent_head(hlist, type, event_id);
8179 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
8181 struct perf_sample_data *data,
8182 struct pt_regs *regs)
8184 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8185 struct perf_event *event;
8186 struct hlist_head *head;
8189 head = find_swevent_head_rcu(swhash, type, event_id);
8193 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8194 if (perf_swevent_match(event, type, event_id, data, regs))
8195 perf_swevent_event(event, nr, data, regs);
8201 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8203 int perf_swevent_get_recursion_context(void)
8205 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8207 return get_recursion_context(swhash->recursion);
8209 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8211 void perf_swevent_put_recursion_context(int rctx)
8213 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8215 put_recursion_context(swhash->recursion, rctx);
8218 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8220 struct perf_sample_data data;
8222 if (WARN_ON_ONCE(!regs))
8225 perf_sample_data_init(&data, addr, 0);
8226 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8229 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8233 preempt_disable_notrace();
8234 rctx = perf_swevent_get_recursion_context();
8235 if (unlikely(rctx < 0))
8238 ___perf_sw_event(event_id, nr, regs, addr);
8240 perf_swevent_put_recursion_context(rctx);
8242 preempt_enable_notrace();
8245 static void perf_swevent_read(struct perf_event *event)
8249 static int perf_swevent_add(struct perf_event *event, int flags)
8251 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8252 struct hw_perf_event *hwc = &event->hw;
8253 struct hlist_head *head;
8255 if (is_sampling_event(event)) {
8256 hwc->last_period = hwc->sample_period;
8257 perf_swevent_set_period(event);
8260 hwc->state = !(flags & PERF_EF_START);
8262 head = find_swevent_head(swhash, event);
8263 if (WARN_ON_ONCE(!head))
8266 hlist_add_head_rcu(&event->hlist_entry, head);
8267 perf_event_update_userpage(event);
8272 static void perf_swevent_del(struct perf_event *event, int flags)
8274 hlist_del_rcu(&event->hlist_entry);
8277 static void perf_swevent_start(struct perf_event *event, int flags)
8279 event->hw.state = 0;
8282 static void perf_swevent_stop(struct perf_event *event, int flags)
8284 event->hw.state = PERF_HES_STOPPED;
8287 /* Deref the hlist from the update side */
8288 static inline struct swevent_hlist *
8289 swevent_hlist_deref(struct swevent_htable *swhash)
8291 return rcu_dereference_protected(swhash->swevent_hlist,
8292 lockdep_is_held(&swhash->hlist_mutex));
8295 static void swevent_hlist_release(struct swevent_htable *swhash)
8297 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
8302 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
8303 kfree_rcu(hlist, rcu_head);
8306 static void swevent_hlist_put_cpu(int cpu)
8308 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8310 mutex_lock(&swhash->hlist_mutex);
8312 if (!--swhash->hlist_refcount)
8313 swevent_hlist_release(swhash);
8315 mutex_unlock(&swhash->hlist_mutex);
8318 static void swevent_hlist_put(void)
8322 for_each_possible_cpu(cpu)
8323 swevent_hlist_put_cpu(cpu);
8326 static int swevent_hlist_get_cpu(int cpu)
8328 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8331 mutex_lock(&swhash->hlist_mutex);
8332 if (!swevent_hlist_deref(swhash) &&
8333 cpumask_test_cpu(cpu, perf_online_mask)) {
8334 struct swevent_hlist *hlist;
8336 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
8341 rcu_assign_pointer(swhash->swevent_hlist, hlist);
8343 swhash->hlist_refcount++;
8345 mutex_unlock(&swhash->hlist_mutex);
8350 static int swevent_hlist_get(void)
8352 int err, cpu, failed_cpu;
8354 mutex_lock(&pmus_lock);
8355 for_each_possible_cpu(cpu) {
8356 err = swevent_hlist_get_cpu(cpu);
8362 mutex_unlock(&pmus_lock);
8365 for_each_possible_cpu(cpu) {
8366 if (cpu == failed_cpu)
8368 swevent_hlist_put_cpu(cpu);
8370 mutex_unlock(&pmus_lock);
8374 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
8376 static void sw_perf_event_destroy(struct perf_event *event)
8378 u64 event_id = event->attr.config;
8380 WARN_ON(event->parent);
8382 static_key_slow_dec(&perf_swevent_enabled[event_id]);
8383 swevent_hlist_put();
8386 static int perf_swevent_init(struct perf_event *event)
8388 u64 event_id = event->attr.config;
8390 if (event->attr.type != PERF_TYPE_SOFTWARE)
8394 * no branch sampling for software events
8396 if (has_branch_stack(event))
8400 case PERF_COUNT_SW_CPU_CLOCK:
8401 case PERF_COUNT_SW_TASK_CLOCK:
8408 if (event_id >= PERF_COUNT_SW_MAX)
8411 if (!event->parent) {
8414 err = swevent_hlist_get();
8418 static_key_slow_inc(&perf_swevent_enabled[event_id]);
8419 event->destroy = sw_perf_event_destroy;
8425 static struct pmu perf_swevent = {
8426 .task_ctx_nr = perf_sw_context,
8428 .capabilities = PERF_PMU_CAP_NO_NMI,
8430 .event_init = perf_swevent_init,
8431 .add = perf_swevent_add,
8432 .del = perf_swevent_del,
8433 .start = perf_swevent_start,
8434 .stop = perf_swevent_stop,
8435 .read = perf_swevent_read,
8438 #ifdef CONFIG_EVENT_TRACING
8440 static int perf_tp_filter_match(struct perf_event *event,
8441 struct perf_sample_data *data)
8443 void *record = data->raw->frag.data;
8445 /* only top level events have filters set */
8447 event = event->parent;
8449 if (likely(!event->filter) || filter_match_preds(event->filter, record))
8454 static int perf_tp_event_match(struct perf_event *event,
8455 struct perf_sample_data *data,
8456 struct pt_regs *regs)
8458 if (event->hw.state & PERF_HES_STOPPED)
8461 * All tracepoints are from kernel-space.
8463 if (event->attr.exclude_kernel)
8466 if (!perf_tp_filter_match(event, data))
8472 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8473 struct trace_event_call *call, u64 count,
8474 struct pt_regs *regs, struct hlist_head *head,
8475 struct task_struct *task)
8477 if (bpf_prog_array_valid(call)) {
8478 *(struct pt_regs **)raw_data = regs;
8479 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
8480 perf_swevent_put_recursion_context(rctx);
8484 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8487 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8489 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8490 struct pt_regs *regs, struct hlist_head *head, int rctx,
8491 struct task_struct *task)
8493 struct perf_sample_data data;
8494 struct perf_event *event;
8496 struct perf_raw_record raw = {
8503 perf_sample_data_init(&data, 0, 0);
8506 perf_trace_buf_update(record, event_type);
8508 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8509 if (perf_tp_event_match(event, &data, regs))
8510 perf_swevent_event(event, count, &data, regs);
8514 * If we got specified a target task, also iterate its context and
8515 * deliver this event there too.
8517 if (task && task != current) {
8518 struct perf_event_context *ctx;
8519 struct trace_entry *entry = record;
8522 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8526 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8527 if (event->cpu != smp_processor_id())
8529 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8531 if (event->attr.config != entry->type)
8533 if (perf_tp_event_match(event, &data, regs))
8534 perf_swevent_event(event, count, &data, regs);
8540 perf_swevent_put_recursion_context(rctx);
8542 EXPORT_SYMBOL_GPL(perf_tp_event);
8544 static void tp_perf_event_destroy(struct perf_event *event)
8546 perf_trace_destroy(event);
8549 static int perf_tp_event_init(struct perf_event *event)
8553 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8557 * no branch sampling for tracepoint events
8559 if (has_branch_stack(event))
8562 err = perf_trace_init(event);
8566 event->destroy = tp_perf_event_destroy;
8571 static struct pmu perf_tracepoint = {
8572 .task_ctx_nr = perf_sw_context,
8574 .event_init = perf_tp_event_init,
8575 .add = perf_trace_add,
8576 .del = perf_trace_del,
8577 .start = perf_swevent_start,
8578 .stop = perf_swevent_stop,
8579 .read = perf_swevent_read,
8582 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
8584 * Flags in config, used by dynamic PMU kprobe and uprobe
8585 * The flags should match following PMU_FORMAT_ATTR().
8587 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
8588 * if not set, create kprobe/uprobe
8590 enum perf_probe_config {
8591 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
8594 PMU_FORMAT_ATTR(retprobe, "config:0");
8596 static struct attribute *probe_attrs[] = {
8597 &format_attr_retprobe.attr,
8601 static struct attribute_group probe_format_group = {
8603 .attrs = probe_attrs,
8606 static const struct attribute_group *probe_attr_groups[] = {
8607 &probe_format_group,
8612 #ifdef CONFIG_KPROBE_EVENTS
8613 static int perf_kprobe_event_init(struct perf_event *event);
8614 static struct pmu perf_kprobe = {
8615 .task_ctx_nr = perf_sw_context,
8616 .event_init = perf_kprobe_event_init,
8617 .add = perf_trace_add,
8618 .del = perf_trace_del,
8619 .start = perf_swevent_start,
8620 .stop = perf_swevent_stop,
8621 .read = perf_swevent_read,
8622 .attr_groups = probe_attr_groups,
8625 static int perf_kprobe_event_init(struct perf_event *event)
8630 if (event->attr.type != perf_kprobe.type)
8633 if (!capable(CAP_SYS_ADMIN))
8637 * no branch sampling for probe events
8639 if (has_branch_stack(event))
8642 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8643 err = perf_kprobe_init(event, is_retprobe);
8647 event->destroy = perf_kprobe_destroy;
8651 #endif /* CONFIG_KPROBE_EVENTS */
8653 #ifdef CONFIG_UPROBE_EVENTS
8654 static int perf_uprobe_event_init(struct perf_event *event);
8655 static struct pmu perf_uprobe = {
8656 .task_ctx_nr = perf_sw_context,
8657 .event_init = perf_uprobe_event_init,
8658 .add = perf_trace_add,
8659 .del = perf_trace_del,
8660 .start = perf_swevent_start,
8661 .stop = perf_swevent_stop,
8662 .read = perf_swevent_read,
8663 .attr_groups = probe_attr_groups,
8666 static int perf_uprobe_event_init(struct perf_event *event)
8671 if (event->attr.type != perf_uprobe.type)
8674 if (!capable(CAP_SYS_ADMIN))
8678 * no branch sampling for probe events
8680 if (has_branch_stack(event))
8683 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8684 err = perf_uprobe_init(event, is_retprobe);
8688 event->destroy = perf_uprobe_destroy;
8692 #endif /* CONFIG_UPROBE_EVENTS */
8694 static inline void perf_tp_register(void)
8696 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8697 #ifdef CONFIG_KPROBE_EVENTS
8698 perf_pmu_register(&perf_kprobe, "kprobe", -1);
8700 #ifdef CONFIG_UPROBE_EVENTS
8701 perf_pmu_register(&perf_uprobe, "uprobe", -1);
8705 static void perf_event_free_filter(struct perf_event *event)
8707 ftrace_profile_free_filter(event);
8710 #ifdef CONFIG_BPF_SYSCALL
8711 static void bpf_overflow_handler(struct perf_event *event,
8712 struct perf_sample_data *data,
8713 struct pt_regs *regs)
8715 struct bpf_perf_event_data_kern ctx = {
8721 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
8723 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8726 ret = BPF_PROG_RUN(event->prog, &ctx);
8729 __this_cpu_dec(bpf_prog_active);
8734 event->orig_overflow_handler(event, data, regs);
8737 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8739 struct bpf_prog *prog;
8741 if (event->overflow_handler_context)
8742 /* hw breakpoint or kernel counter */
8748 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8750 return PTR_ERR(prog);
8753 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8754 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8758 static void perf_event_free_bpf_handler(struct perf_event *event)
8760 struct bpf_prog *prog = event->prog;
8765 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8770 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8774 static void perf_event_free_bpf_handler(struct perf_event *event)
8780 * returns true if the event is a tracepoint, or a kprobe/upprobe created
8781 * with perf_event_open()
8783 static inline bool perf_event_is_tracing(struct perf_event *event)
8785 if (event->pmu == &perf_tracepoint)
8787 #ifdef CONFIG_KPROBE_EVENTS
8788 if (event->pmu == &perf_kprobe)
8791 #ifdef CONFIG_UPROBE_EVENTS
8792 if (event->pmu == &perf_uprobe)
8798 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8800 bool is_kprobe, is_tracepoint, is_syscall_tp;
8801 struct bpf_prog *prog;
8804 if (!perf_event_is_tracing(event))
8805 return perf_event_set_bpf_handler(event, prog_fd);
8807 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8808 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8809 is_syscall_tp = is_syscall_trace_event(event->tp_event);
8810 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
8811 /* bpf programs can only be attached to u/kprobe or tracepoint */
8814 prog = bpf_prog_get(prog_fd);
8816 return PTR_ERR(prog);
8818 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8819 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
8820 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8821 /* valid fd, but invalid bpf program type */
8826 /* Kprobe override only works for kprobes, not uprobes. */
8827 if (prog->kprobe_override &&
8828 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
8833 if (is_tracepoint || is_syscall_tp) {
8834 int off = trace_event_get_offsets(event->tp_event);
8836 if (prog->aux->max_ctx_offset > off) {
8842 ret = perf_event_attach_bpf_prog(event, prog);
8848 static void perf_event_free_bpf_prog(struct perf_event *event)
8850 if (!perf_event_is_tracing(event)) {
8851 perf_event_free_bpf_handler(event);
8854 perf_event_detach_bpf_prog(event);
8859 static inline void perf_tp_register(void)
8863 static void perf_event_free_filter(struct perf_event *event)
8867 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8872 static void perf_event_free_bpf_prog(struct perf_event *event)
8875 #endif /* CONFIG_EVENT_TRACING */
8877 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8878 void perf_bp_event(struct perf_event *bp, void *data)
8880 struct perf_sample_data sample;
8881 struct pt_regs *regs = data;
8883 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8885 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8886 perf_swevent_event(bp, 1, &sample, regs);
8891 * Allocate a new address filter
8893 static struct perf_addr_filter *
8894 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8896 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8897 struct perf_addr_filter *filter;
8899 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8903 INIT_LIST_HEAD(&filter->entry);
8904 list_add_tail(&filter->entry, filters);
8909 static void free_filters_list(struct list_head *filters)
8911 struct perf_addr_filter *filter, *iter;
8913 list_for_each_entry_safe(filter, iter, filters, entry) {
8914 path_put(&filter->path);
8915 list_del(&filter->entry);
8921 * Free existing address filters and optionally install new ones
8923 static void perf_addr_filters_splice(struct perf_event *event,
8924 struct list_head *head)
8926 unsigned long flags;
8929 if (!has_addr_filter(event))
8932 /* don't bother with children, they don't have their own filters */
8936 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8938 list_splice_init(&event->addr_filters.list, &list);
8940 list_splice(head, &event->addr_filters.list);
8942 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8944 free_filters_list(&list);
8948 * Scan through mm's vmas and see if one of them matches the
8949 * @filter; if so, adjust filter's address range.
8950 * Called with mm::mmap_sem down for reading.
8952 static void perf_addr_filter_apply(struct perf_addr_filter *filter,
8953 struct mm_struct *mm,
8954 struct perf_addr_filter_range *fr)
8956 struct vm_area_struct *vma;
8958 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8962 if (perf_addr_filter_vma_adjust(filter, vma, fr))
8968 * Update event's address range filters based on the
8969 * task's existing mappings, if any.
8971 static void perf_event_addr_filters_apply(struct perf_event *event)
8973 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8974 struct task_struct *task = READ_ONCE(event->ctx->task);
8975 struct perf_addr_filter *filter;
8976 struct mm_struct *mm = NULL;
8977 unsigned int count = 0;
8978 unsigned long flags;
8981 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8982 * will stop on the parent's child_mutex that our caller is also holding
8984 if (task == TASK_TOMBSTONE)
8987 if (ifh->nr_file_filters) {
8988 mm = get_task_mm(task);
8992 down_read(&mm->mmap_sem);
8995 raw_spin_lock_irqsave(&ifh->lock, flags);
8996 list_for_each_entry(filter, &ifh->list, entry) {
8997 if (filter->path.dentry) {
8999 * Adjust base offset if the filter is associated to a
9000 * binary that needs to be mapped:
9002 event->addr_filter_ranges[count].start = 0;
9003 event->addr_filter_ranges[count].size = 0;
9005 perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
9007 event->addr_filter_ranges[count].start = filter->offset;
9008 event->addr_filter_ranges[count].size = filter->size;
9014 event->addr_filters_gen++;
9015 raw_spin_unlock_irqrestore(&ifh->lock, flags);
9017 if (ifh->nr_file_filters) {
9018 up_read(&mm->mmap_sem);
9024 perf_event_stop(event, 1);
9028 * Address range filtering: limiting the data to certain
9029 * instruction address ranges. Filters are ioctl()ed to us from
9030 * userspace as ascii strings.
9032 * Filter string format:
9035 * where ACTION is one of the
9036 * * "filter": limit the trace to this region
9037 * * "start": start tracing from this address
9038 * * "stop": stop tracing at this address/region;
9040 * * for kernel addresses: <start address>[/<size>]
9041 * * for object files: <start address>[/<size>]@</path/to/object/file>
9043 * if <size> is not specified or is zero, the range is treated as a single
9044 * address; not valid for ACTION=="filter".
9058 IF_STATE_ACTION = 0,
9063 static const match_table_t if_tokens = {
9064 { IF_ACT_FILTER, "filter" },
9065 { IF_ACT_START, "start" },
9066 { IF_ACT_STOP, "stop" },
9067 { IF_SRC_FILE, "%u/%u@%s" },
9068 { IF_SRC_KERNEL, "%u/%u" },
9069 { IF_SRC_FILEADDR, "%u@%s" },
9070 { IF_SRC_KERNELADDR, "%u" },
9071 { IF_ACT_NONE, NULL },
9075 * Address filter string parser
9078 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
9079 struct list_head *filters)
9081 struct perf_addr_filter *filter = NULL;
9082 char *start, *orig, *filename = NULL;
9083 substring_t args[MAX_OPT_ARGS];
9084 int state = IF_STATE_ACTION, token;
9085 unsigned int kernel = 0;
9088 orig = fstr = kstrdup(fstr, GFP_KERNEL);
9092 while ((start = strsep(&fstr, " ,\n")) != NULL) {
9093 static const enum perf_addr_filter_action_t actions[] = {
9094 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
9095 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
9096 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
9103 /* filter definition begins */
9104 if (state == IF_STATE_ACTION) {
9105 filter = perf_addr_filter_new(event, filters);
9110 token = match_token(start, if_tokens, args);
9115 if (state != IF_STATE_ACTION)
9118 filter->action = actions[token];
9119 state = IF_STATE_SOURCE;
9122 case IF_SRC_KERNELADDR:
9126 case IF_SRC_FILEADDR:
9128 if (state != IF_STATE_SOURCE)
9132 ret = kstrtoul(args[0].from, 0, &filter->offset);
9136 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
9138 ret = kstrtoul(args[1].from, 0, &filter->size);
9143 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
9144 int fpos = token == IF_SRC_FILE ? 2 : 1;
9147 filename = match_strdup(&args[fpos]);
9154 state = IF_STATE_END;
9162 * Filter definition is fully parsed, validate and install it.
9163 * Make sure that it doesn't contradict itself or the event's
9166 if (state == IF_STATE_END) {
9168 if (kernel && event->attr.exclude_kernel)
9172 * ACTION "filter" must have a non-zero length region
9175 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9184 * For now, we only support file-based filters
9185 * in per-task events; doing so for CPU-wide
9186 * events requires additional context switching
9187 * trickery, since same object code will be
9188 * mapped at different virtual addresses in
9189 * different processes.
9192 if (!event->ctx->task)
9195 /* look up the path and grab its inode */
9196 ret = kern_path(filename, LOOKUP_FOLLOW,
9202 if (!filter->path.dentry ||
9203 !S_ISREG(d_inode(filter->path.dentry)
9207 event->addr_filters.nr_file_filters++;
9210 /* ready to consume more filters */
9213 state = IF_STATE_ACTION;
9219 if (state != IF_STATE_ACTION)
9229 free_filters_list(filters);
9236 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
9242 * Since this is called in perf_ioctl() path, we're already holding
9245 lockdep_assert_held(&event->ctx->mutex);
9247 if (WARN_ON_ONCE(event->parent))
9250 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
9252 goto fail_clear_files;
9254 ret = event->pmu->addr_filters_validate(&filters);
9256 goto fail_free_filters;
9258 /* remove existing filters, if any */
9259 perf_addr_filters_splice(event, &filters);
9261 /* install new filters */
9262 perf_event_for_each_child(event, perf_event_addr_filters_apply);
9267 free_filters_list(&filters);
9270 event->addr_filters.nr_file_filters = 0;
9275 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
9280 filter_str = strndup_user(arg, PAGE_SIZE);
9281 if (IS_ERR(filter_str))
9282 return PTR_ERR(filter_str);
9284 #ifdef CONFIG_EVENT_TRACING
9285 if (perf_event_is_tracing(event)) {
9286 struct perf_event_context *ctx = event->ctx;
9289 * Beware, here be dragons!!
9291 * the tracepoint muck will deadlock against ctx->mutex, but
9292 * the tracepoint stuff does not actually need it. So
9293 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
9294 * already have a reference on ctx.
9296 * This can result in event getting moved to a different ctx,
9297 * but that does not affect the tracepoint state.
9299 mutex_unlock(&ctx->mutex);
9300 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
9301 mutex_lock(&ctx->mutex);
9304 if (has_addr_filter(event))
9305 ret = perf_event_set_addr_filter(event, filter_str);
9312 * hrtimer based swevent callback
9315 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
9317 enum hrtimer_restart ret = HRTIMER_RESTART;
9318 struct perf_sample_data data;
9319 struct pt_regs *regs;
9320 struct perf_event *event;
9323 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
9325 if (event->state != PERF_EVENT_STATE_ACTIVE)
9326 return HRTIMER_NORESTART;
9328 event->pmu->read(event);
9330 perf_sample_data_init(&data, 0, event->hw.last_period);
9331 regs = get_irq_regs();
9333 if (regs && !perf_exclude_event(event, regs)) {
9334 if (!(event->attr.exclude_idle && is_idle_task(current)))
9335 if (__perf_event_overflow(event, 1, &data, regs))
9336 ret = HRTIMER_NORESTART;
9339 period = max_t(u64, 10000, event->hw.sample_period);
9340 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
9345 static void perf_swevent_start_hrtimer(struct perf_event *event)
9347 struct hw_perf_event *hwc = &event->hw;
9350 if (!is_sampling_event(event))
9353 period = local64_read(&hwc->period_left);
9358 local64_set(&hwc->period_left, 0);
9360 period = max_t(u64, 10000, hwc->sample_period);
9362 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
9363 HRTIMER_MODE_REL_PINNED);
9366 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
9368 struct hw_perf_event *hwc = &event->hw;
9370 if (is_sampling_event(event)) {
9371 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
9372 local64_set(&hwc->period_left, ktime_to_ns(remaining));
9374 hrtimer_cancel(&hwc->hrtimer);
9378 static void perf_swevent_init_hrtimer(struct perf_event *event)
9380 struct hw_perf_event *hwc = &event->hw;
9382 if (!is_sampling_event(event))
9385 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
9386 hwc->hrtimer.function = perf_swevent_hrtimer;
9389 * Since hrtimers have a fixed rate, we can do a static freq->period
9390 * mapping and avoid the whole period adjust feedback stuff.
9392 if (event->attr.freq) {
9393 long freq = event->attr.sample_freq;
9395 event->attr.sample_period = NSEC_PER_SEC / freq;
9396 hwc->sample_period = event->attr.sample_period;
9397 local64_set(&hwc->period_left, hwc->sample_period);
9398 hwc->last_period = hwc->sample_period;
9399 event->attr.freq = 0;
9404 * Software event: cpu wall time clock
9407 static void cpu_clock_event_update(struct perf_event *event)
9412 now = local_clock();
9413 prev = local64_xchg(&event->hw.prev_count, now);
9414 local64_add(now - prev, &event->count);
9417 static void cpu_clock_event_start(struct perf_event *event, int flags)
9419 local64_set(&event->hw.prev_count, local_clock());
9420 perf_swevent_start_hrtimer(event);
9423 static void cpu_clock_event_stop(struct perf_event *event, int flags)
9425 perf_swevent_cancel_hrtimer(event);
9426 cpu_clock_event_update(event);
9429 static int cpu_clock_event_add(struct perf_event *event, int flags)
9431 if (flags & PERF_EF_START)
9432 cpu_clock_event_start(event, flags);
9433 perf_event_update_userpage(event);
9438 static void cpu_clock_event_del(struct perf_event *event, int flags)
9440 cpu_clock_event_stop(event, flags);
9443 static void cpu_clock_event_read(struct perf_event *event)
9445 cpu_clock_event_update(event);
9448 static int cpu_clock_event_init(struct perf_event *event)
9450 if (event->attr.type != PERF_TYPE_SOFTWARE)
9453 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
9457 * no branch sampling for software events
9459 if (has_branch_stack(event))
9462 perf_swevent_init_hrtimer(event);
9467 static struct pmu perf_cpu_clock = {
9468 .task_ctx_nr = perf_sw_context,
9470 .capabilities = PERF_PMU_CAP_NO_NMI,
9472 .event_init = cpu_clock_event_init,
9473 .add = cpu_clock_event_add,
9474 .del = cpu_clock_event_del,
9475 .start = cpu_clock_event_start,
9476 .stop = cpu_clock_event_stop,
9477 .read = cpu_clock_event_read,
9481 * Software event: task time clock
9484 static void task_clock_event_update(struct perf_event *event, u64 now)
9489 prev = local64_xchg(&event->hw.prev_count, now);
9491 local64_add(delta, &event->count);
9494 static void task_clock_event_start(struct perf_event *event, int flags)
9496 local64_set(&event->hw.prev_count, event->ctx->time);
9497 perf_swevent_start_hrtimer(event);
9500 static void task_clock_event_stop(struct perf_event *event, int flags)
9502 perf_swevent_cancel_hrtimer(event);
9503 task_clock_event_update(event, event->ctx->time);
9506 static int task_clock_event_add(struct perf_event *event, int flags)
9508 if (flags & PERF_EF_START)
9509 task_clock_event_start(event, flags);
9510 perf_event_update_userpage(event);
9515 static void task_clock_event_del(struct perf_event *event, int flags)
9517 task_clock_event_stop(event, PERF_EF_UPDATE);
9520 static void task_clock_event_read(struct perf_event *event)
9522 u64 now = perf_clock();
9523 u64 delta = now - event->ctx->timestamp;
9524 u64 time = event->ctx->time + delta;
9526 task_clock_event_update(event, time);
9529 static int task_clock_event_init(struct perf_event *event)
9531 if (event->attr.type != PERF_TYPE_SOFTWARE)
9534 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
9538 * no branch sampling for software events
9540 if (has_branch_stack(event))
9543 perf_swevent_init_hrtimer(event);
9548 static struct pmu perf_task_clock = {
9549 .task_ctx_nr = perf_sw_context,
9551 .capabilities = PERF_PMU_CAP_NO_NMI,
9553 .event_init = task_clock_event_init,
9554 .add = task_clock_event_add,
9555 .del = task_clock_event_del,
9556 .start = task_clock_event_start,
9557 .stop = task_clock_event_stop,
9558 .read = task_clock_event_read,
9561 static void perf_pmu_nop_void(struct pmu *pmu)
9565 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
9569 static int perf_pmu_nop_int(struct pmu *pmu)
9574 static int perf_event_nop_int(struct perf_event *event, u64 value)
9579 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
9581 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
9583 __this_cpu_write(nop_txn_flags, flags);
9585 if (flags & ~PERF_PMU_TXN_ADD)
9588 perf_pmu_disable(pmu);
9591 static int perf_pmu_commit_txn(struct pmu *pmu)
9593 unsigned int flags = __this_cpu_read(nop_txn_flags);
9595 __this_cpu_write(nop_txn_flags, 0);
9597 if (flags & ~PERF_PMU_TXN_ADD)
9600 perf_pmu_enable(pmu);
9604 static void perf_pmu_cancel_txn(struct pmu *pmu)
9606 unsigned int flags = __this_cpu_read(nop_txn_flags);
9608 __this_cpu_write(nop_txn_flags, 0);
9610 if (flags & ~PERF_PMU_TXN_ADD)
9613 perf_pmu_enable(pmu);
9616 static int perf_event_idx_default(struct perf_event *event)
9622 * Ensures all contexts with the same task_ctx_nr have the same
9623 * pmu_cpu_context too.
9625 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
9632 list_for_each_entry(pmu, &pmus, entry) {
9633 if (pmu->task_ctx_nr == ctxn)
9634 return pmu->pmu_cpu_context;
9640 static void free_pmu_context(struct pmu *pmu)
9643 * Static contexts such as perf_sw_context have a global lifetime
9644 * and may be shared between different PMUs. Avoid freeing them
9645 * when a single PMU is going away.
9647 if (pmu->task_ctx_nr > perf_invalid_context)
9650 free_percpu(pmu->pmu_cpu_context);
9654 * Let userspace know that this PMU supports address range filtering:
9656 static ssize_t nr_addr_filters_show(struct device *dev,
9657 struct device_attribute *attr,
9660 struct pmu *pmu = dev_get_drvdata(dev);
9662 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
9664 DEVICE_ATTR_RO(nr_addr_filters);
9666 static struct idr pmu_idr;
9669 type_show(struct device *dev, struct device_attribute *attr, char *page)
9671 struct pmu *pmu = dev_get_drvdata(dev);
9673 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
9675 static DEVICE_ATTR_RO(type);
9678 perf_event_mux_interval_ms_show(struct device *dev,
9679 struct device_attribute *attr,
9682 struct pmu *pmu = dev_get_drvdata(dev);
9684 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9687 static DEFINE_MUTEX(mux_interval_mutex);
9690 perf_event_mux_interval_ms_store(struct device *dev,
9691 struct device_attribute *attr,
9692 const char *buf, size_t count)
9694 struct pmu *pmu = dev_get_drvdata(dev);
9695 int timer, cpu, ret;
9697 ret = kstrtoint(buf, 0, &timer);
9704 /* same value, noting to do */
9705 if (timer == pmu->hrtimer_interval_ms)
9708 mutex_lock(&mux_interval_mutex);
9709 pmu->hrtimer_interval_ms = timer;
9711 /* update all cpuctx for this PMU */
9713 for_each_online_cpu(cpu) {
9714 struct perf_cpu_context *cpuctx;
9715 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9716 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9718 cpu_function_call(cpu, perf_mux_hrtimer_restart_ipi, cpuctx);
9721 mutex_unlock(&mux_interval_mutex);
9725 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9727 static struct attribute *pmu_dev_attrs[] = {
9728 &dev_attr_type.attr,
9729 &dev_attr_perf_event_mux_interval_ms.attr,
9732 ATTRIBUTE_GROUPS(pmu_dev);
9734 static int pmu_bus_running;
9735 static struct bus_type pmu_bus = {
9736 .name = "event_source",
9737 .dev_groups = pmu_dev_groups,
9740 static void pmu_dev_release(struct device *dev)
9745 static int pmu_dev_alloc(struct pmu *pmu)
9749 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9753 pmu->dev->groups = pmu->attr_groups;
9754 device_initialize(pmu->dev);
9756 dev_set_drvdata(pmu->dev, pmu);
9757 pmu->dev->bus = &pmu_bus;
9758 pmu->dev->release = pmu_dev_release;
9760 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9764 ret = device_add(pmu->dev);
9768 /* For PMUs with address filters, throw in an extra attribute: */
9769 if (pmu->nr_addr_filters)
9770 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9779 device_del(pmu->dev);
9782 put_device(pmu->dev);
9786 static struct lock_class_key cpuctx_mutex;
9787 static struct lock_class_key cpuctx_lock;
9789 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9793 mutex_lock(&pmus_lock);
9795 pmu->pmu_disable_count = alloc_percpu(int);
9796 if (!pmu->pmu_disable_count)
9805 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9813 if (pmu_bus_running) {
9814 ret = pmu_dev_alloc(pmu);
9820 if (pmu->task_ctx_nr == perf_hw_context) {
9821 static int hw_context_taken = 0;
9824 * Other than systems with heterogeneous CPUs, it never makes
9825 * sense for two PMUs to share perf_hw_context. PMUs which are
9826 * uncore must use perf_invalid_context.
9828 if (WARN_ON_ONCE(hw_context_taken &&
9829 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9830 pmu->task_ctx_nr = perf_invalid_context;
9832 hw_context_taken = 1;
9835 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9836 if (pmu->pmu_cpu_context)
9837 goto got_cpu_context;
9840 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9841 if (!pmu->pmu_cpu_context)
9844 for_each_possible_cpu(cpu) {
9845 struct perf_cpu_context *cpuctx;
9847 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9848 __perf_event_init_context(&cpuctx->ctx);
9849 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9850 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9851 cpuctx->ctx.pmu = pmu;
9852 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9854 __perf_mux_hrtimer_init(cpuctx, cpu);
9858 if (!pmu->start_txn) {
9859 if (pmu->pmu_enable) {
9861 * If we have pmu_enable/pmu_disable calls, install
9862 * transaction stubs that use that to try and batch
9863 * hardware accesses.
9865 pmu->start_txn = perf_pmu_start_txn;
9866 pmu->commit_txn = perf_pmu_commit_txn;
9867 pmu->cancel_txn = perf_pmu_cancel_txn;
9869 pmu->start_txn = perf_pmu_nop_txn;
9870 pmu->commit_txn = perf_pmu_nop_int;
9871 pmu->cancel_txn = perf_pmu_nop_void;
9875 if (!pmu->pmu_enable) {
9876 pmu->pmu_enable = perf_pmu_nop_void;
9877 pmu->pmu_disable = perf_pmu_nop_void;
9880 if (!pmu->check_period)
9881 pmu->check_period = perf_event_nop_int;
9883 if (!pmu->event_idx)
9884 pmu->event_idx = perf_event_idx_default;
9886 list_add_rcu(&pmu->entry, &pmus);
9887 atomic_set(&pmu->exclusive_cnt, 0);
9890 mutex_unlock(&pmus_lock);
9895 device_del(pmu->dev);
9896 put_device(pmu->dev);
9899 if (pmu->type >= PERF_TYPE_MAX)
9900 idr_remove(&pmu_idr, pmu->type);
9903 free_percpu(pmu->pmu_disable_count);
9906 EXPORT_SYMBOL_GPL(perf_pmu_register);
9908 void perf_pmu_unregister(struct pmu *pmu)
9910 mutex_lock(&pmus_lock);
9911 list_del_rcu(&pmu->entry);
9914 * We dereference the pmu list under both SRCU and regular RCU, so
9915 * synchronize against both of those.
9917 synchronize_srcu(&pmus_srcu);
9920 free_percpu(pmu->pmu_disable_count);
9921 if (pmu->type >= PERF_TYPE_MAX)
9922 idr_remove(&pmu_idr, pmu->type);
9923 if (pmu_bus_running) {
9924 if (pmu->nr_addr_filters)
9925 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9926 device_del(pmu->dev);
9927 put_device(pmu->dev);
9929 free_pmu_context(pmu);
9930 mutex_unlock(&pmus_lock);
9932 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9934 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9936 struct perf_event_context *ctx = NULL;
9939 if (!try_module_get(pmu->module))
9943 * A number of pmu->event_init() methods iterate the sibling_list to,
9944 * for example, validate if the group fits on the PMU. Therefore,
9945 * if this is a sibling event, acquire the ctx->mutex to protect
9948 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
9950 * This ctx->mutex can nest when we're called through
9951 * inheritance. See the perf_event_ctx_lock_nested() comment.
9953 ctx = perf_event_ctx_lock_nested(event->group_leader,
9954 SINGLE_DEPTH_NESTING);
9959 ret = pmu->event_init(event);
9962 perf_event_ctx_unlock(event->group_leader, ctx);
9965 module_put(pmu->module);
9970 static struct pmu *perf_init_event(struct perf_event *event)
9976 idx = srcu_read_lock(&pmus_srcu);
9978 /* Try parent's PMU first: */
9979 if (event->parent && event->parent->pmu) {
9980 pmu = event->parent->pmu;
9981 ret = perf_try_init_event(pmu, event);
9987 pmu = idr_find(&pmu_idr, event->attr.type);
9990 ret = perf_try_init_event(pmu, event);
9996 list_for_each_entry_rcu(pmu, &pmus, entry) {
9997 ret = perf_try_init_event(pmu, event);
10001 if (ret != -ENOENT) {
10002 pmu = ERR_PTR(ret);
10006 pmu = ERR_PTR(-ENOENT);
10008 srcu_read_unlock(&pmus_srcu, idx);
10013 static void attach_sb_event(struct perf_event *event)
10015 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
10017 raw_spin_lock(&pel->lock);
10018 list_add_rcu(&event->sb_list, &pel->list);
10019 raw_spin_unlock(&pel->lock);
10023 * We keep a list of all !task (and therefore per-cpu) events
10024 * that need to receive side-band records.
10026 * This avoids having to scan all the various PMU per-cpu contexts
10027 * looking for them.
10029 static void account_pmu_sb_event(struct perf_event *event)
10031 if (is_sb_event(event))
10032 attach_sb_event(event);
10035 static void account_event_cpu(struct perf_event *event, int cpu)
10040 if (is_cgroup_event(event))
10041 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
10044 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
10045 static void account_freq_event_nohz(void)
10047 #ifdef CONFIG_NO_HZ_FULL
10048 /* Lock so we don't race with concurrent unaccount */
10049 spin_lock(&nr_freq_lock);
10050 if (atomic_inc_return(&nr_freq_events) == 1)
10051 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
10052 spin_unlock(&nr_freq_lock);
10056 static void account_freq_event(void)
10058 if (tick_nohz_full_enabled())
10059 account_freq_event_nohz();
10061 atomic_inc(&nr_freq_events);
10065 static void account_event(struct perf_event *event)
10072 if (event->attach_state & PERF_ATTACH_TASK)
10074 if (event->attr.mmap || event->attr.mmap_data)
10075 atomic_inc(&nr_mmap_events);
10076 if (event->attr.comm)
10077 atomic_inc(&nr_comm_events);
10078 if (event->attr.namespaces)
10079 atomic_inc(&nr_namespaces_events);
10080 if (event->attr.task)
10081 atomic_inc(&nr_task_events);
10082 if (event->attr.freq)
10083 account_freq_event();
10084 if (event->attr.context_switch) {
10085 atomic_inc(&nr_switch_events);
10088 if (has_branch_stack(event))
10090 if (is_cgroup_event(event))
10095 * We need the mutex here because static_branch_enable()
10096 * must complete *before* the perf_sched_count increment
10099 if (atomic_inc_not_zero(&perf_sched_count))
10102 mutex_lock(&perf_sched_mutex);
10103 if (!atomic_read(&perf_sched_count)) {
10104 static_branch_enable(&perf_sched_events);
10106 * Guarantee that all CPUs observe they key change and
10107 * call the perf scheduling hooks before proceeding to
10108 * install events that need them.
10110 synchronize_sched();
10113 * Now that we have waited for the sync_sched(), allow further
10114 * increments to by-pass the mutex.
10116 atomic_inc(&perf_sched_count);
10117 mutex_unlock(&perf_sched_mutex);
10121 account_event_cpu(event, event->cpu);
10123 account_pmu_sb_event(event);
10127 * Allocate and initialize an event structure
10129 static struct perf_event *
10130 perf_event_alloc(struct perf_event_attr *attr, int cpu,
10131 struct task_struct *task,
10132 struct perf_event *group_leader,
10133 struct perf_event *parent_event,
10134 perf_overflow_handler_t overflow_handler,
10135 void *context, int cgroup_fd)
10138 struct perf_event *event;
10139 struct hw_perf_event *hwc;
10140 long err = -EINVAL;
10142 if ((unsigned)cpu >= nr_cpu_ids) {
10143 if (!task || cpu != -1)
10144 return ERR_PTR(-EINVAL);
10147 event = kzalloc(sizeof(*event), GFP_KERNEL);
10149 return ERR_PTR(-ENOMEM);
10152 * Single events are their own group leaders, with an
10153 * empty sibling list:
10156 group_leader = event;
10158 mutex_init(&event->child_mutex);
10159 INIT_LIST_HEAD(&event->child_list);
10161 INIT_LIST_HEAD(&event->event_entry);
10162 INIT_LIST_HEAD(&event->sibling_list);
10163 INIT_LIST_HEAD(&event->active_list);
10164 init_event_group(event);
10165 INIT_LIST_HEAD(&event->rb_entry);
10166 INIT_LIST_HEAD(&event->active_entry);
10167 INIT_LIST_HEAD(&event->addr_filters.list);
10168 INIT_HLIST_NODE(&event->hlist_entry);
10171 init_waitqueue_head(&event->waitq);
10172 event->pending_disable = -1;
10173 init_irq_work(&event->pending, perf_pending_event);
10175 mutex_init(&event->mmap_mutex);
10176 raw_spin_lock_init(&event->addr_filters.lock);
10178 atomic_long_set(&event->refcount, 1);
10180 event->attr = *attr;
10181 event->group_leader = group_leader;
10185 event->parent = parent_event;
10187 event->ns = get_pid_ns(task_active_pid_ns(current));
10188 event->id = atomic64_inc_return(&perf_event_id);
10190 event->state = PERF_EVENT_STATE_INACTIVE;
10193 event->attach_state = PERF_ATTACH_TASK;
10195 * XXX pmu::event_init needs to know what task to account to
10196 * and we cannot use the ctx information because we need the
10197 * pmu before we get a ctx.
10199 get_task_struct(task);
10200 event->hw.target = task;
10203 event->clock = &local_clock;
10205 event->clock = parent_event->clock;
10207 if (!overflow_handler && parent_event) {
10208 overflow_handler = parent_event->overflow_handler;
10209 context = parent_event->overflow_handler_context;
10210 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
10211 if (overflow_handler == bpf_overflow_handler) {
10212 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
10214 if (IS_ERR(prog)) {
10215 err = PTR_ERR(prog);
10218 event->prog = prog;
10219 event->orig_overflow_handler =
10220 parent_event->orig_overflow_handler;
10225 if (overflow_handler) {
10226 event->overflow_handler = overflow_handler;
10227 event->overflow_handler_context = context;
10228 } else if (is_write_backward(event)){
10229 event->overflow_handler = perf_event_output_backward;
10230 event->overflow_handler_context = NULL;
10232 event->overflow_handler = perf_event_output_forward;
10233 event->overflow_handler_context = NULL;
10236 perf_event__state_init(event);
10241 hwc->sample_period = attr->sample_period;
10242 if (attr->freq && attr->sample_freq)
10243 hwc->sample_period = 1;
10244 hwc->last_period = hwc->sample_period;
10246 local64_set(&hwc->period_left, hwc->sample_period);
10249 * We currently do not support PERF_SAMPLE_READ on inherited events.
10250 * See perf_output_read().
10252 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
10255 if (!has_branch_stack(event))
10256 event->attr.branch_sample_type = 0;
10258 if (cgroup_fd != -1) {
10259 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
10264 pmu = perf_init_event(event);
10266 err = PTR_ERR(pmu);
10270 err = exclusive_event_init(event);
10274 if (has_addr_filter(event)) {
10275 event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
10276 sizeof(struct perf_addr_filter_range),
10278 if (!event->addr_filter_ranges) {
10284 * Clone the parent's vma offsets: they are valid until exec()
10285 * even if the mm is not shared with the parent.
10287 if (event->parent) {
10288 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10290 raw_spin_lock_irq(&ifh->lock);
10291 memcpy(event->addr_filter_ranges,
10292 event->parent->addr_filter_ranges,
10293 pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
10294 raw_spin_unlock_irq(&ifh->lock);
10297 /* force hw sync on the address filters */
10298 event->addr_filters_gen = 1;
10301 if (!event->parent) {
10302 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
10303 err = get_callchain_buffers(attr->sample_max_stack);
10305 goto err_addr_filters;
10309 /* symmetric to unaccount_event() in _free_event() */
10310 account_event(event);
10315 kfree(event->addr_filter_ranges);
10318 exclusive_event_destroy(event);
10321 if (event->destroy)
10322 event->destroy(event);
10323 module_put(pmu->module);
10325 if (is_cgroup_event(event))
10326 perf_detach_cgroup(event);
10328 put_pid_ns(event->ns);
10329 if (event->hw.target)
10330 put_task_struct(event->hw.target);
10333 return ERR_PTR(err);
10336 static int perf_copy_attr(struct perf_event_attr __user *uattr,
10337 struct perf_event_attr *attr)
10342 if (!access_ok(VERIFY_WRITE, uattr, PERF_ATTR_SIZE_VER0))
10346 * zero the full structure, so that a short copy will be nice.
10348 memset(attr, 0, sizeof(*attr));
10350 ret = get_user(size, &uattr->size);
10354 if (size > PAGE_SIZE) /* silly large */
10357 if (!size) /* abi compat */
10358 size = PERF_ATTR_SIZE_VER0;
10360 if (size < PERF_ATTR_SIZE_VER0)
10364 * If we're handed a bigger struct than we know of,
10365 * ensure all the unknown bits are 0 - i.e. new
10366 * user-space does not rely on any kernel feature
10367 * extensions we dont know about yet.
10369 if (size > sizeof(*attr)) {
10370 unsigned char __user *addr;
10371 unsigned char __user *end;
10374 addr = (void __user *)uattr + sizeof(*attr);
10375 end = (void __user *)uattr + size;
10377 for (; addr < end; addr++) {
10378 ret = get_user(val, addr);
10384 size = sizeof(*attr);
10387 ret = copy_from_user(attr, uattr, size);
10393 if (attr->__reserved_1)
10396 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
10399 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
10402 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
10403 u64 mask = attr->branch_sample_type;
10405 /* only using defined bits */
10406 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
10409 /* at least one branch bit must be set */
10410 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
10413 /* propagate priv level, when not set for branch */
10414 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
10416 /* exclude_kernel checked on syscall entry */
10417 if (!attr->exclude_kernel)
10418 mask |= PERF_SAMPLE_BRANCH_KERNEL;
10420 if (!attr->exclude_user)
10421 mask |= PERF_SAMPLE_BRANCH_USER;
10423 if (!attr->exclude_hv)
10424 mask |= PERF_SAMPLE_BRANCH_HV;
10426 * adjust user setting (for HW filter setup)
10428 attr->branch_sample_type = mask;
10430 /* privileged levels capture (kernel, hv): check permissions */
10431 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
10432 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10436 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
10437 ret = perf_reg_validate(attr->sample_regs_user);
10442 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
10443 if (!arch_perf_have_user_stack_dump())
10447 * We have __u32 type for the size, but so far
10448 * we can only use __u16 as maximum due to the
10449 * __u16 sample size limit.
10451 if (attr->sample_stack_user >= USHRT_MAX)
10453 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
10457 if (!attr->sample_max_stack)
10458 attr->sample_max_stack = sysctl_perf_event_max_stack;
10460 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
10461 ret = perf_reg_validate(attr->sample_regs_intr);
10466 put_user(sizeof(*attr), &uattr->size);
10471 static void mutex_lock_double(struct mutex *a, struct mutex *b)
10477 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
10481 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
10483 struct ring_buffer *rb = NULL;
10486 if (!output_event) {
10487 mutex_lock(&event->mmap_mutex);
10491 /* don't allow circular references */
10492 if (event == output_event)
10496 * Don't allow cross-cpu buffers
10498 if (output_event->cpu != event->cpu)
10502 * If its not a per-cpu rb, it must be the same task.
10504 if (output_event->cpu == -1 && output_event->hw.target != event->hw.target)
10508 * Mixing clocks in the same buffer is trouble you don't need.
10510 if (output_event->clock != event->clock)
10514 * Either writing ring buffer from beginning or from end.
10515 * Mixing is not allowed.
10517 if (is_write_backward(output_event) != is_write_backward(event))
10521 * If both events generate aux data, they must be on the same PMU
10523 if (has_aux(event) && has_aux(output_event) &&
10524 event->pmu != output_event->pmu)
10528 * Hold both mmap_mutex to serialize against perf_mmap_close(). Since
10529 * output_event is already on rb->event_list, and the list iteration
10530 * restarts after every removal, it is guaranteed this new event is
10531 * observed *OR* if output_event is already removed, it's guaranteed we
10532 * observe !rb->mmap_count.
10534 mutex_lock_double(&event->mmap_mutex, &output_event->mmap_mutex);
10536 /* Can't redirect output if we've got an active mmap() */
10537 if (atomic_read(&event->mmap_count))
10540 if (output_event) {
10541 /* get the rb we want to redirect to */
10542 rb = ring_buffer_get(output_event);
10546 /* did we race against perf_mmap_close() */
10547 if (!atomic_read(&rb->mmap_count)) {
10548 ring_buffer_put(rb);
10553 ring_buffer_attach(event, rb);
10557 mutex_unlock(&event->mmap_mutex);
10559 mutex_unlock(&output_event->mmap_mutex);
10565 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
10567 bool nmi_safe = false;
10570 case CLOCK_MONOTONIC:
10571 event->clock = &ktime_get_mono_fast_ns;
10575 case CLOCK_MONOTONIC_RAW:
10576 event->clock = &ktime_get_raw_fast_ns;
10580 case CLOCK_REALTIME:
10581 event->clock = &ktime_get_real_ns;
10584 case CLOCK_BOOTTIME:
10585 event->clock = &ktime_get_boot_ns;
10589 event->clock = &ktime_get_tai_ns;
10596 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
10603 * Variation on perf_event_ctx_lock_nested(), except we take two context
10606 static struct perf_event_context *
10607 __perf_event_ctx_lock_double(struct perf_event *group_leader,
10608 struct perf_event_context *ctx)
10610 struct perf_event_context *gctx;
10614 gctx = READ_ONCE(group_leader->ctx);
10615 if (!atomic_inc_not_zero(&gctx->refcount)) {
10621 mutex_lock_double(&gctx->mutex, &ctx->mutex);
10623 if (group_leader->ctx != gctx) {
10624 mutex_unlock(&ctx->mutex);
10625 mutex_unlock(&gctx->mutex);
10634 * sys_perf_event_open - open a performance event, associate it to a task/cpu
10636 * @attr_uptr: event_id type attributes for monitoring/sampling
10639 * @group_fd: group leader event fd
10641 SYSCALL_DEFINE5(perf_event_open,
10642 struct perf_event_attr __user *, attr_uptr,
10643 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
10645 struct perf_event *group_leader = NULL, *output_event = NULL;
10646 struct perf_event *event, *sibling;
10647 struct perf_event_attr attr;
10648 struct perf_event_context *ctx, *gctx;
10649 struct file *event_file = NULL;
10650 struct fd group = {NULL, 0};
10651 struct task_struct *task = NULL;
10654 int move_group = 0;
10656 int f_flags = O_RDWR;
10657 int cgroup_fd = -1;
10659 /* for future expandability... */
10660 if (flags & ~PERF_FLAG_ALL)
10663 err = perf_copy_attr(attr_uptr, &attr);
10667 if (!attr.exclude_kernel) {
10668 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10672 if (attr.namespaces) {
10673 if (!capable(CAP_SYS_ADMIN))
10678 if (attr.sample_freq > sysctl_perf_event_sample_rate)
10681 if (attr.sample_period & (1ULL << 63))
10685 /* Only privileged users can get physical addresses */
10686 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
10687 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10691 * In cgroup mode, the pid argument is used to pass the fd
10692 * opened to the cgroup directory in cgroupfs. The cpu argument
10693 * designates the cpu on which to monitor threads from that
10696 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
10699 if (flags & PERF_FLAG_FD_CLOEXEC)
10700 f_flags |= O_CLOEXEC;
10702 event_fd = get_unused_fd_flags(f_flags);
10706 if (group_fd != -1) {
10707 err = perf_fget_light(group_fd, &group);
10710 group_leader = group.file->private_data;
10711 if (flags & PERF_FLAG_FD_OUTPUT)
10712 output_event = group_leader;
10713 if (flags & PERF_FLAG_FD_NO_GROUP)
10714 group_leader = NULL;
10717 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
10718 task = find_lively_task_by_vpid(pid);
10719 if (IS_ERR(task)) {
10720 err = PTR_ERR(task);
10725 if (task && group_leader &&
10726 group_leader->attr.inherit != attr.inherit) {
10732 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
10737 * Reuse ptrace permission checks for now.
10739 * We must hold cred_guard_mutex across this and any potential
10740 * perf_install_in_context() call for this new event to
10741 * serialize against exec() altering our credentials (and the
10742 * perf_event_exit_task() that could imply).
10745 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
10749 if (flags & PERF_FLAG_PID_CGROUP)
10752 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10753 NULL, NULL, cgroup_fd);
10754 if (IS_ERR(event)) {
10755 err = PTR_ERR(event);
10759 if (is_sampling_event(event)) {
10760 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
10767 * Special case software events and allow them to be part of
10768 * any hardware group.
10772 if (attr.use_clockid) {
10773 err = perf_event_set_clock(event, attr.clockid);
10778 if (pmu->task_ctx_nr == perf_sw_context)
10779 event->event_caps |= PERF_EV_CAP_SOFTWARE;
10781 if (group_leader) {
10782 if (is_software_event(event) &&
10783 !in_software_context(group_leader)) {
10785 * If the event is a sw event, but the group_leader
10786 * is on hw context.
10788 * Allow the addition of software events to hw
10789 * groups, this is safe because software events
10790 * never fail to schedule.
10792 pmu = group_leader->ctx->pmu;
10793 } else if (!is_software_event(event) &&
10794 is_software_event(group_leader) &&
10795 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10797 * In case the group is a pure software group, and we
10798 * try to add a hardware event, move the whole group to
10799 * the hardware context.
10806 * Get the target context (task or percpu):
10808 ctx = find_get_context(pmu, task, event);
10810 err = PTR_ERR(ctx);
10815 * Look up the group leader (we will attach this event to it):
10817 if (group_leader) {
10821 * Do not allow a recursive hierarchy (this new sibling
10822 * becoming part of another group-sibling):
10824 if (group_leader->group_leader != group_leader)
10827 /* All events in a group should have the same clock */
10828 if (group_leader->clock != event->clock)
10832 * Make sure we're both events for the same CPU;
10833 * grouping events for different CPUs is broken; since
10834 * you can never concurrently schedule them anyhow.
10836 if (group_leader->cpu != event->cpu)
10840 * Make sure we're both on the same task, or both
10843 if (group_leader->ctx->task != ctx->task)
10847 * Do not allow to attach to a group in a different task
10848 * or CPU context. If we're moving SW events, we'll fix
10849 * this up later, so allow that.
10851 * Racy, not holding group_leader->ctx->mutex, see comment with
10852 * perf_event_ctx_lock().
10854 if (!move_group && group_leader->ctx != ctx)
10858 * Only a group leader can be exclusive or pinned
10860 if (attr.exclusive || attr.pinned)
10864 if (output_event) {
10865 err = perf_event_set_output(event, output_event);
10870 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10872 if (IS_ERR(event_file)) {
10873 err = PTR_ERR(event_file);
10879 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10881 if (gctx->task == TASK_TOMBSTONE) {
10887 * Check if we raced against another sys_perf_event_open() call
10888 * moving the software group underneath us.
10890 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10892 * If someone moved the group out from under us, check
10893 * if this new event wound up on the same ctx, if so
10894 * its the regular !move_group case, otherwise fail.
10900 perf_event_ctx_unlock(group_leader, gctx);
10902 goto not_move_group;
10907 * Failure to create exclusive events returns -EBUSY.
10910 if (!exclusive_event_installable(group_leader, ctx))
10913 for_each_sibling_event(sibling, group_leader) {
10914 if (!exclusive_event_installable(sibling, ctx))
10918 mutex_lock(&ctx->mutex);
10921 * Now that we hold ctx->lock, (re)validate group_leader->ctx == ctx,
10922 * see the group_leader && !move_group test earlier.
10924 if (group_leader && group_leader->ctx != ctx) {
10931 if (ctx->task == TASK_TOMBSTONE) {
10936 if (!perf_event_validate_size(event)) {
10943 * Check if the @cpu we're creating an event for is online.
10945 * We use the perf_cpu_context::ctx::mutex to serialize against
10946 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10948 struct perf_cpu_context *cpuctx =
10949 container_of(ctx, struct perf_cpu_context, ctx);
10951 if (!cpuctx->online) {
10959 * Must be under the same ctx::mutex as perf_install_in_context(),
10960 * because we need to serialize with concurrent event creation.
10962 if (!exclusive_event_installable(event, ctx)) {
10967 WARN_ON_ONCE(ctx->parent_ctx);
10970 * This is the point on no return; we cannot fail hereafter. This is
10971 * where we start modifying current state.
10976 * See perf_event_ctx_lock() for comments on the details
10977 * of swizzling perf_event::ctx.
10979 perf_remove_from_context(group_leader, 0);
10982 for_each_sibling_event(sibling, group_leader) {
10983 perf_remove_from_context(sibling, 0);
10988 * Wait for everybody to stop referencing the events through
10989 * the old lists, before installing it on new lists.
10994 * Install the group siblings before the group leader.
10996 * Because a group leader will try and install the entire group
10997 * (through the sibling list, which is still in-tact), we can
10998 * end up with siblings installed in the wrong context.
11000 * By installing siblings first we NO-OP because they're not
11001 * reachable through the group lists.
11003 for_each_sibling_event(sibling, group_leader) {
11004 perf_event__state_init(sibling);
11005 perf_install_in_context(ctx, sibling, sibling->cpu);
11010 * Removing from the context ends up with disabled
11011 * event. What we want here is event in the initial
11012 * startup state, ready to be add into new context.
11014 perf_event__state_init(group_leader);
11015 perf_install_in_context(ctx, group_leader, group_leader->cpu);
11020 * Precalculate sample_data sizes; do while holding ctx::mutex such
11021 * that we're serialized against further additions and before
11022 * perf_install_in_context() which is the point the event is active and
11023 * can use these values.
11025 perf_event__header_size(event);
11026 perf_event__id_header_size(event);
11028 event->owner = current;
11030 perf_install_in_context(ctx, event, event->cpu);
11031 perf_unpin_context(ctx);
11034 perf_event_ctx_unlock(group_leader, gctx);
11035 mutex_unlock(&ctx->mutex);
11038 mutex_unlock(&task->signal->cred_guard_mutex);
11039 put_task_struct(task);
11042 mutex_lock(¤t->perf_event_mutex);
11043 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
11044 mutex_unlock(¤t->perf_event_mutex);
11047 * Drop the reference on the group_event after placing the
11048 * new event on the sibling_list. This ensures destruction
11049 * of the group leader will find the pointer to itself in
11050 * perf_group_detach().
11053 fd_install(event_fd, event_file);
11058 perf_event_ctx_unlock(group_leader, gctx);
11059 mutex_unlock(&ctx->mutex);
11063 perf_unpin_context(ctx);
11067 * If event_file is set, the fput() above will have called ->release()
11068 * and that will take care of freeing the event.
11074 mutex_unlock(&task->signal->cred_guard_mutex);
11077 put_task_struct(task);
11081 put_unused_fd(event_fd);
11086 * perf_event_create_kernel_counter
11088 * @attr: attributes of the counter to create
11089 * @cpu: cpu in which the counter is bound
11090 * @task: task to profile (NULL for percpu)
11092 struct perf_event *
11093 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
11094 struct task_struct *task,
11095 perf_overflow_handler_t overflow_handler,
11098 struct perf_event_context *ctx;
11099 struct perf_event *event;
11103 * Get the target context (task or percpu):
11106 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
11107 overflow_handler, context, -1);
11108 if (IS_ERR(event)) {
11109 err = PTR_ERR(event);
11113 /* Mark owner so we could distinguish it from user events. */
11114 event->owner = TASK_TOMBSTONE;
11116 ctx = find_get_context(event->pmu, task, event);
11118 err = PTR_ERR(ctx);
11122 WARN_ON_ONCE(ctx->parent_ctx);
11123 mutex_lock(&ctx->mutex);
11124 if (ctx->task == TASK_TOMBSTONE) {
11131 * Check if the @cpu we're creating an event for is online.
11133 * We use the perf_cpu_context::ctx::mutex to serialize against
11134 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
11136 struct perf_cpu_context *cpuctx =
11137 container_of(ctx, struct perf_cpu_context, ctx);
11138 if (!cpuctx->online) {
11144 if (!exclusive_event_installable(event, ctx)) {
11149 perf_install_in_context(ctx, event, event->cpu);
11150 perf_unpin_context(ctx);
11151 mutex_unlock(&ctx->mutex);
11156 mutex_unlock(&ctx->mutex);
11157 perf_unpin_context(ctx);
11162 return ERR_PTR(err);
11164 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
11166 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
11168 struct perf_event_context *src_ctx;
11169 struct perf_event_context *dst_ctx;
11170 struct perf_event *event, *tmp;
11173 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
11174 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
11177 * See perf_event_ctx_lock() for comments on the details
11178 * of swizzling perf_event::ctx.
11180 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
11181 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
11183 perf_remove_from_context(event, 0);
11184 unaccount_event_cpu(event, src_cpu);
11186 list_add(&event->migrate_entry, &events);
11190 * Wait for the events to quiesce before re-instating them.
11195 * Re-instate events in 2 passes.
11197 * Skip over group leaders and only install siblings on this first
11198 * pass, siblings will not get enabled without a leader, however a
11199 * leader will enable its siblings, even if those are still on the old
11202 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11203 if (event->group_leader == event)
11206 list_del(&event->migrate_entry);
11207 if (event->state >= PERF_EVENT_STATE_OFF)
11208 event->state = PERF_EVENT_STATE_INACTIVE;
11209 account_event_cpu(event, dst_cpu);
11210 perf_install_in_context(dst_ctx, event, dst_cpu);
11215 * Once all the siblings are setup properly, install the group leaders
11218 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
11219 list_del(&event->migrate_entry);
11220 if (event->state >= PERF_EVENT_STATE_OFF)
11221 event->state = PERF_EVENT_STATE_INACTIVE;
11222 account_event_cpu(event, dst_cpu);
11223 perf_install_in_context(dst_ctx, event, dst_cpu);
11226 mutex_unlock(&dst_ctx->mutex);
11227 mutex_unlock(&src_ctx->mutex);
11229 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
11231 static void sync_child_event(struct perf_event *child_event,
11232 struct task_struct *child)
11234 struct perf_event *parent_event = child_event->parent;
11237 if (child_event->attr.inherit_stat)
11238 perf_event_read_event(child_event, child);
11240 child_val = perf_event_count(child_event);
11243 * Add back the child's count to the parent's count:
11245 atomic64_add(child_val, &parent_event->child_count);
11246 atomic64_add(child_event->total_time_enabled,
11247 &parent_event->child_total_time_enabled);
11248 atomic64_add(child_event->total_time_running,
11249 &parent_event->child_total_time_running);
11253 perf_event_exit_event(struct perf_event *child_event,
11254 struct perf_event_context *child_ctx,
11255 struct task_struct *child)
11257 struct perf_event *parent_event = child_event->parent;
11260 * Do not destroy the 'original' grouping; because of the context
11261 * switch optimization the original events could've ended up in a
11262 * random child task.
11264 * If we were to destroy the original group, all group related
11265 * operations would cease to function properly after this random
11268 * Do destroy all inherited groups, we don't care about those
11269 * and being thorough is better.
11271 raw_spin_lock_irq(&child_ctx->lock);
11272 WARN_ON_ONCE(child_ctx->is_active);
11275 perf_group_detach(child_event);
11276 list_del_event(child_event, child_ctx);
11277 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
11278 raw_spin_unlock_irq(&child_ctx->lock);
11281 * Parent events are governed by their filedesc, retain them.
11283 if (!parent_event) {
11284 perf_event_wakeup(child_event);
11288 * Child events can be cleaned up.
11291 sync_child_event(child_event, child);
11294 * Remove this event from the parent's list
11296 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
11297 mutex_lock(&parent_event->child_mutex);
11298 list_del_init(&child_event->child_list);
11299 mutex_unlock(&parent_event->child_mutex);
11302 * Kick perf_poll() for is_event_hup().
11304 perf_event_wakeup(parent_event);
11305 free_event(child_event);
11306 put_event(parent_event);
11309 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
11311 struct perf_event_context *child_ctx, *clone_ctx = NULL;
11312 struct perf_event *child_event, *next;
11314 WARN_ON_ONCE(child != current);
11316 child_ctx = perf_pin_task_context(child, ctxn);
11321 * In order to reduce the amount of tricky in ctx tear-down, we hold
11322 * ctx::mutex over the entire thing. This serializes against almost
11323 * everything that wants to access the ctx.
11325 * The exception is sys_perf_event_open() /
11326 * perf_event_create_kernel_count() which does find_get_context()
11327 * without ctx::mutex (it cannot because of the move_group double mutex
11328 * lock thing). See the comments in perf_install_in_context().
11330 mutex_lock(&child_ctx->mutex);
11333 * In a single ctx::lock section, de-schedule the events and detach the
11334 * context from the task such that we cannot ever get it scheduled back
11337 raw_spin_lock_irq(&child_ctx->lock);
11338 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
11341 * Now that the context is inactive, destroy the task <-> ctx relation
11342 * and mark the context dead.
11344 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
11345 put_ctx(child_ctx); /* cannot be last */
11346 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
11347 put_task_struct(current); /* cannot be last */
11349 clone_ctx = unclone_ctx(child_ctx);
11350 raw_spin_unlock_irq(&child_ctx->lock);
11353 put_ctx(clone_ctx);
11356 * Report the task dead after unscheduling the events so that we
11357 * won't get any samples after PERF_RECORD_EXIT. We can however still
11358 * get a few PERF_RECORD_READ events.
11360 perf_event_task(child, child_ctx, 0);
11362 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
11363 perf_event_exit_event(child_event, child_ctx, child);
11365 mutex_unlock(&child_ctx->mutex);
11367 put_ctx(child_ctx);
11371 * When a child task exits, feed back event values to parent events.
11373 * Can be called with cred_guard_mutex held when called from
11374 * install_exec_creds().
11376 void perf_event_exit_task(struct task_struct *child)
11378 struct perf_event *event, *tmp;
11381 mutex_lock(&child->perf_event_mutex);
11382 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
11384 list_del_init(&event->owner_entry);
11387 * Ensure the list deletion is visible before we clear
11388 * the owner, closes a race against perf_release() where
11389 * we need to serialize on the owner->perf_event_mutex.
11391 smp_store_release(&event->owner, NULL);
11393 mutex_unlock(&child->perf_event_mutex);
11395 for_each_task_context_nr(ctxn)
11396 perf_event_exit_task_context(child, ctxn);
11399 * The perf_event_exit_task_context calls perf_event_task
11400 * with child's task_ctx, which generates EXIT events for
11401 * child contexts and sets child->perf_event_ctxp[] to NULL.
11402 * At this point we need to send EXIT events to cpu contexts.
11404 perf_event_task(child, NULL, 0);
11407 static void perf_free_event(struct perf_event *event,
11408 struct perf_event_context *ctx)
11410 struct perf_event *parent = event->parent;
11412 if (WARN_ON_ONCE(!parent))
11415 mutex_lock(&parent->child_mutex);
11416 list_del_init(&event->child_list);
11417 mutex_unlock(&parent->child_mutex);
11421 raw_spin_lock_irq(&ctx->lock);
11422 perf_group_detach(event);
11423 list_del_event(event, ctx);
11424 raw_spin_unlock_irq(&ctx->lock);
11429 * Free a context as created by inheritance by perf_event_init_task() below,
11430 * used by fork() in case of fail.
11432 * Even though the task has never lived, the context and events have been
11433 * exposed through the child_list, so we must take care tearing it all down.
11435 void perf_event_free_task(struct task_struct *task)
11437 struct perf_event_context *ctx;
11438 struct perf_event *event, *tmp;
11441 for_each_task_context_nr(ctxn) {
11442 ctx = task->perf_event_ctxp[ctxn];
11446 mutex_lock(&ctx->mutex);
11447 raw_spin_lock_irq(&ctx->lock);
11449 * Destroy the task <-> ctx relation and mark the context dead.
11451 * This is important because even though the task hasn't been
11452 * exposed yet the context has been (through child_list).
11454 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
11455 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
11456 put_task_struct(task); /* cannot be last */
11457 raw_spin_unlock_irq(&ctx->lock);
11459 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
11460 perf_free_event(event, ctx);
11462 mutex_unlock(&ctx->mutex);
11465 * perf_event_release_kernel() could've stolen some of our
11466 * child events and still have them on its free_list. In that
11467 * case we must wait for these events to have been freed (in
11468 * particular all their references to this task must've been
11471 * Without this copy_process() will unconditionally free this
11472 * task (irrespective of its reference count) and
11473 * _free_event()'s put_task_struct(event->hw.target) will be a
11476 * Wait for all events to drop their context reference.
11478 wait_var_event(&ctx->refcount, atomic_read(&ctx->refcount) == 1);
11479 put_ctx(ctx); /* must be last */
11483 void perf_event_delayed_put(struct task_struct *task)
11487 for_each_task_context_nr(ctxn)
11488 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
11491 struct file *perf_event_get(unsigned int fd)
11495 file = fget_raw(fd);
11497 return ERR_PTR(-EBADF);
11499 if (file->f_op != &perf_fops) {
11501 return ERR_PTR(-EBADF);
11507 const struct perf_event *perf_get_event(struct file *file)
11509 if (file->f_op != &perf_fops)
11510 return ERR_PTR(-EINVAL);
11512 return file->private_data;
11515 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
11518 return ERR_PTR(-EINVAL);
11520 return &event->attr;
11524 * Inherit an event from parent task to child task.
11527 * - valid pointer on success
11528 * - NULL for orphaned events
11529 * - IS_ERR() on error
11531 static struct perf_event *
11532 inherit_event(struct perf_event *parent_event,
11533 struct task_struct *parent,
11534 struct perf_event_context *parent_ctx,
11535 struct task_struct *child,
11536 struct perf_event *group_leader,
11537 struct perf_event_context *child_ctx)
11539 enum perf_event_state parent_state = parent_event->state;
11540 struct perf_event *child_event;
11541 unsigned long flags;
11544 * Instead of creating recursive hierarchies of events,
11545 * we link inherited events back to the original parent,
11546 * which has a filp for sure, which we use as the reference
11549 if (parent_event->parent)
11550 parent_event = parent_event->parent;
11552 child_event = perf_event_alloc(&parent_event->attr,
11555 group_leader, parent_event,
11557 if (IS_ERR(child_event))
11558 return child_event;
11561 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
11562 !child_ctx->task_ctx_data) {
11563 struct pmu *pmu = child_event->pmu;
11565 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
11567 if (!child_ctx->task_ctx_data) {
11568 free_event(child_event);
11569 return ERR_PTR(-ENOMEM);
11574 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
11575 * must be under the same lock in order to serialize against
11576 * perf_event_release_kernel(), such that either we must observe
11577 * is_orphaned_event() or they will observe us on the child_list.
11579 mutex_lock(&parent_event->child_mutex);
11580 if (is_orphaned_event(parent_event) ||
11581 !atomic_long_inc_not_zero(&parent_event->refcount)) {
11582 mutex_unlock(&parent_event->child_mutex);
11583 /* task_ctx_data is freed with child_ctx */
11584 free_event(child_event);
11588 get_ctx(child_ctx);
11591 * Make the child state follow the state of the parent event,
11592 * not its attr.disabled bit. We hold the parent's mutex,
11593 * so we won't race with perf_event_{en, dis}able_family.
11595 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
11596 child_event->state = PERF_EVENT_STATE_INACTIVE;
11598 child_event->state = PERF_EVENT_STATE_OFF;
11600 if (parent_event->attr.freq) {
11601 u64 sample_period = parent_event->hw.sample_period;
11602 struct hw_perf_event *hwc = &child_event->hw;
11604 hwc->sample_period = sample_period;
11605 hwc->last_period = sample_period;
11607 local64_set(&hwc->period_left, sample_period);
11610 child_event->ctx = child_ctx;
11611 child_event->overflow_handler = parent_event->overflow_handler;
11612 child_event->overflow_handler_context
11613 = parent_event->overflow_handler_context;
11616 * Precalculate sample_data sizes
11618 perf_event__header_size(child_event);
11619 perf_event__id_header_size(child_event);
11622 * Link it up in the child's context:
11624 raw_spin_lock_irqsave(&child_ctx->lock, flags);
11625 add_event_to_ctx(child_event, child_ctx);
11626 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
11629 * Link this into the parent event's child list
11631 list_add_tail(&child_event->child_list, &parent_event->child_list);
11632 mutex_unlock(&parent_event->child_mutex);
11634 return child_event;
11638 * Inherits an event group.
11640 * This will quietly suppress orphaned events; !inherit_event() is not an error.
11641 * This matches with perf_event_release_kernel() removing all child events.
11647 static int inherit_group(struct perf_event *parent_event,
11648 struct task_struct *parent,
11649 struct perf_event_context *parent_ctx,
11650 struct task_struct *child,
11651 struct perf_event_context *child_ctx)
11653 struct perf_event *leader;
11654 struct perf_event *sub;
11655 struct perf_event *child_ctr;
11657 leader = inherit_event(parent_event, parent, parent_ctx,
11658 child, NULL, child_ctx);
11659 if (IS_ERR(leader))
11660 return PTR_ERR(leader);
11662 * @leader can be NULL here because of is_orphaned_event(). In this
11663 * case inherit_event() will create individual events, similar to what
11664 * perf_group_detach() would do anyway.
11666 for_each_sibling_event(sub, parent_event) {
11667 child_ctr = inherit_event(sub, parent, parent_ctx,
11668 child, leader, child_ctx);
11669 if (IS_ERR(child_ctr))
11670 return PTR_ERR(child_ctr);
11673 leader->group_generation = parent_event->group_generation;
11678 * Creates the child task context and tries to inherit the event-group.
11680 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
11681 * inherited_all set when we 'fail' to inherit an orphaned event; this is
11682 * consistent with perf_event_release_kernel() removing all child events.
11689 inherit_task_group(struct perf_event *event, struct task_struct *parent,
11690 struct perf_event_context *parent_ctx,
11691 struct task_struct *child, int ctxn,
11692 int *inherited_all)
11695 struct perf_event_context *child_ctx;
11697 if (!event->attr.inherit) {
11698 *inherited_all = 0;
11702 child_ctx = child->perf_event_ctxp[ctxn];
11705 * This is executed from the parent task context, so
11706 * inherit events that have been marked for cloning.
11707 * First allocate and initialize a context for the
11710 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
11714 child->perf_event_ctxp[ctxn] = child_ctx;
11717 ret = inherit_group(event, parent, parent_ctx,
11721 *inherited_all = 0;
11727 * Initialize the perf_event context in task_struct
11729 static int perf_event_init_context(struct task_struct *child, int ctxn)
11731 struct perf_event_context *child_ctx, *parent_ctx;
11732 struct perf_event_context *cloned_ctx;
11733 struct perf_event *event;
11734 struct task_struct *parent = current;
11735 int inherited_all = 1;
11736 unsigned long flags;
11739 if (likely(!parent->perf_event_ctxp[ctxn]))
11743 * If the parent's context is a clone, pin it so it won't get
11744 * swapped under us.
11746 parent_ctx = perf_pin_task_context(parent, ctxn);
11751 * No need to check if parent_ctx != NULL here; since we saw
11752 * it non-NULL earlier, the only reason for it to become NULL
11753 * is if we exit, and since we're currently in the middle of
11754 * a fork we can't be exiting at the same time.
11758 * Lock the parent list. No need to lock the child - not PID
11759 * hashed yet and not running, so nobody can access it.
11761 mutex_lock(&parent_ctx->mutex);
11764 * We dont have to disable NMIs - we are only looking at
11765 * the list, not manipulating it:
11767 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
11768 ret = inherit_task_group(event, parent, parent_ctx,
11769 child, ctxn, &inherited_all);
11775 * We can't hold ctx->lock when iterating the ->flexible_group list due
11776 * to allocations, but we need to prevent rotation because
11777 * rotate_ctx() will change the list from interrupt context.
11779 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11780 parent_ctx->rotate_disable = 1;
11781 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11783 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
11784 ret = inherit_task_group(event, parent, parent_ctx,
11785 child, ctxn, &inherited_all);
11790 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11791 parent_ctx->rotate_disable = 0;
11793 child_ctx = child->perf_event_ctxp[ctxn];
11795 if (child_ctx && inherited_all) {
11797 * Mark the child context as a clone of the parent
11798 * context, or of whatever the parent is a clone of.
11800 * Note that if the parent is a clone, the holding of
11801 * parent_ctx->lock avoids it from being uncloned.
11803 cloned_ctx = parent_ctx->parent_ctx;
11805 child_ctx->parent_ctx = cloned_ctx;
11806 child_ctx->parent_gen = parent_ctx->parent_gen;
11808 child_ctx->parent_ctx = parent_ctx;
11809 child_ctx->parent_gen = parent_ctx->generation;
11811 get_ctx(child_ctx->parent_ctx);
11814 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11816 mutex_unlock(&parent_ctx->mutex);
11818 perf_unpin_context(parent_ctx);
11819 put_ctx(parent_ctx);
11825 * Initialize the perf_event context in task_struct
11827 int perf_event_init_task(struct task_struct *child)
11831 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
11832 mutex_init(&child->perf_event_mutex);
11833 INIT_LIST_HEAD(&child->perf_event_list);
11835 for_each_task_context_nr(ctxn) {
11836 ret = perf_event_init_context(child, ctxn);
11838 perf_event_free_task(child);
11846 static void __init perf_event_init_all_cpus(void)
11848 struct swevent_htable *swhash;
11851 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
11853 for_each_possible_cpu(cpu) {
11854 swhash = &per_cpu(swevent_htable, cpu);
11855 mutex_init(&swhash->hlist_mutex);
11856 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
11858 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
11859 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
11861 #ifdef CONFIG_CGROUP_PERF
11862 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
11864 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
11868 void perf_swevent_init_cpu(unsigned int cpu)
11870 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
11872 mutex_lock(&swhash->hlist_mutex);
11873 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11874 struct swevent_hlist *hlist;
11876 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11878 rcu_assign_pointer(swhash->swevent_hlist, hlist);
11880 mutex_unlock(&swhash->hlist_mutex);
11883 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11884 static void __perf_event_exit_context(void *__info)
11886 struct perf_event_context *ctx = __info;
11887 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11888 struct perf_event *event;
11890 raw_spin_lock(&ctx->lock);
11891 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
11892 list_for_each_entry(event, &ctx->event_list, event_entry)
11893 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11894 raw_spin_unlock(&ctx->lock);
11897 static void perf_event_exit_cpu_context(int cpu)
11899 struct perf_cpu_context *cpuctx;
11900 struct perf_event_context *ctx;
11903 mutex_lock(&pmus_lock);
11904 list_for_each_entry(pmu, &pmus, entry) {
11905 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11906 ctx = &cpuctx->ctx;
11908 mutex_lock(&ctx->mutex);
11909 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11910 cpuctx->online = 0;
11911 mutex_unlock(&ctx->mutex);
11913 cpumask_clear_cpu(cpu, perf_online_mask);
11914 mutex_unlock(&pmus_lock);
11918 static void perf_event_exit_cpu_context(int cpu) { }
11922 int perf_event_init_cpu(unsigned int cpu)
11924 struct perf_cpu_context *cpuctx;
11925 struct perf_event_context *ctx;
11928 perf_swevent_init_cpu(cpu);
11930 mutex_lock(&pmus_lock);
11931 cpumask_set_cpu(cpu, perf_online_mask);
11932 list_for_each_entry(pmu, &pmus, entry) {
11933 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11934 ctx = &cpuctx->ctx;
11936 mutex_lock(&ctx->mutex);
11937 cpuctx->online = 1;
11938 mutex_unlock(&ctx->mutex);
11940 mutex_unlock(&pmus_lock);
11945 int perf_event_exit_cpu(unsigned int cpu)
11947 perf_event_exit_cpu_context(cpu);
11952 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11956 for_each_online_cpu(cpu)
11957 perf_event_exit_cpu(cpu);
11963 * Run the perf reboot notifier at the very last possible moment so that
11964 * the generic watchdog code runs as long as possible.
11966 static struct notifier_block perf_reboot_notifier = {
11967 .notifier_call = perf_reboot,
11968 .priority = INT_MIN,
11971 void __init perf_event_init(void)
11975 idr_init(&pmu_idr);
11977 perf_event_init_all_cpus();
11978 init_srcu_struct(&pmus_srcu);
11979 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11980 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11981 perf_pmu_register(&perf_task_clock, NULL, -1);
11982 perf_tp_register();
11983 perf_event_init_cpu(smp_processor_id());
11984 register_reboot_notifier(&perf_reboot_notifier);
11986 ret = init_hw_breakpoint();
11987 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11990 * Build time assertion that we keep the data_head at the intended
11991 * location. IOW, validation we got the __reserved[] size right.
11993 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11997 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
12000 struct perf_pmu_events_attr *pmu_attr =
12001 container_of(attr, struct perf_pmu_events_attr, attr);
12003 if (pmu_attr->event_str)
12004 return sprintf(page, "%s\n", pmu_attr->event_str);
12008 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
12010 static int __init perf_event_sysfs_init(void)
12015 mutex_lock(&pmus_lock);
12017 ret = bus_register(&pmu_bus);
12021 list_for_each_entry(pmu, &pmus, entry) {
12022 if (!pmu->name || pmu->type < 0)
12025 ret = pmu_dev_alloc(pmu);
12026 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
12028 pmu_bus_running = 1;
12032 mutex_unlock(&pmus_lock);
12036 device_initcall(perf_event_sysfs_init);
12038 #ifdef CONFIG_CGROUP_PERF
12039 static struct cgroup_subsys_state *
12040 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
12042 struct perf_cgroup *jc;
12044 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
12046 return ERR_PTR(-ENOMEM);
12048 jc->info = alloc_percpu(struct perf_cgroup_info);
12051 return ERR_PTR(-ENOMEM);
12057 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
12059 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
12061 free_percpu(jc->info);
12065 static int __perf_cgroup_move(void *info)
12067 struct task_struct *task = info;
12069 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
12074 static void perf_cgroup_attach(struct cgroup_taskset *tset)
12076 struct task_struct *task;
12077 struct cgroup_subsys_state *css;
12079 cgroup_taskset_for_each(task, css, tset)
12080 task_function_call(task, __perf_cgroup_move, task);
12083 struct cgroup_subsys perf_event_cgrp_subsys = {
12084 .css_alloc = perf_cgroup_css_alloc,
12085 .css_free = perf_cgroup_css_free,
12086 .attach = perf_cgroup_attach,
12088 * Implicitly enable on dfl hierarchy so that perf events can
12089 * always be filtered by cgroup2 path as long as perf_event
12090 * controller is not mounted on a legacy hierarchy.
12092 .implicit_on_dfl = true,
12095 #endif /* CONFIG_CGROUP_PERF */