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
99 * returns: @func return value, or
100 * -ESRCH - when the process isn't running
101 * -EAGAIN - when the process moved away
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, &data, 1);
118 } while (ret == -EAGAIN);
124 * cpu_function_call - call a function on the cpu
125 * @func: the function to be called
126 * @info: the function call argument
128 * Calls the function @func on the remote cpu.
130 * returns: @func return value or -ENXIO when the cpu is offline
132 static int cpu_function_call(int cpu, remote_function_f func, void *info)
134 struct remote_function_call data = {
138 .ret = -ENXIO, /* No such CPU */
141 smp_call_function_single(cpu, remote_function, &data, 1);
146 static inline struct perf_cpu_context *
147 __get_cpu_context(struct perf_event_context *ctx)
149 return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
152 static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
153 struct perf_event_context *ctx)
155 raw_spin_lock(&cpuctx->ctx.lock);
157 raw_spin_lock(&ctx->lock);
160 static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
161 struct perf_event_context *ctx)
164 raw_spin_unlock(&ctx->lock);
165 raw_spin_unlock(&cpuctx->ctx.lock);
168 #define TASK_TOMBSTONE ((void *)-1L)
170 static bool is_kernel_event(struct perf_event *event)
172 return READ_ONCE(event->owner) == TASK_TOMBSTONE;
176 * On task ctx scheduling...
178 * When !ctx->nr_events a task context will not be scheduled. This means
179 * we can disable the scheduler hooks (for performance) without leaving
180 * pending task ctx state.
182 * This however results in two special cases:
184 * - removing the last event from a task ctx; this is relatively straight
185 * forward and is done in __perf_remove_from_context.
187 * - adding the first event to a task ctx; this is tricky because we cannot
188 * rely on ctx->is_active and therefore cannot use event_function_call().
189 * See perf_install_in_context().
191 * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
194 typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
195 struct perf_event_context *, void *);
197 struct event_function_struct {
198 struct perf_event *event;
203 static int event_function(void *info)
205 struct event_function_struct *efs = info;
206 struct perf_event *event = efs->event;
207 struct perf_event_context *ctx = event->ctx;
208 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
209 struct perf_event_context *task_ctx = cpuctx->task_ctx;
212 lockdep_assert_irqs_disabled();
214 perf_ctx_lock(cpuctx, task_ctx);
216 * Since we do the IPI call without holding ctx->lock things can have
217 * changed, double check we hit the task we set out to hit.
220 if (ctx->task != current) {
226 * We only use event_function_call() on established contexts,
227 * and event_function() is only ever called when active (or
228 * rather, we'll have bailed in task_function_call() or the
229 * above ctx->task != current test), therefore we must have
230 * ctx->is_active here.
232 WARN_ON_ONCE(!ctx->is_active);
234 * And since we have ctx->is_active, cpuctx->task_ctx must
237 WARN_ON_ONCE(task_ctx != ctx);
239 WARN_ON_ONCE(&cpuctx->ctx != ctx);
242 efs->func(event, cpuctx, ctx, efs->data);
244 perf_ctx_unlock(cpuctx, task_ctx);
249 static void event_function_call(struct perf_event *event, event_f func, void *data)
251 struct perf_event_context *ctx = event->ctx;
252 struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
253 struct event_function_struct efs = {
259 if (!event->parent) {
261 * If this is a !child event, we must hold ctx::mutex to
262 * stabilize the the event->ctx relation. See
263 * perf_event_ctx_lock().
265 lockdep_assert_held(&ctx->mutex);
269 cpu_function_call(event->cpu, event_function, &efs);
273 if (task == TASK_TOMBSTONE)
277 if (!task_function_call(task, event_function, &efs))
280 raw_spin_lock_irq(&ctx->lock);
282 * Reload the task pointer, it might have been changed by
283 * a concurrent perf_event_context_sched_out().
286 if (task == TASK_TOMBSTONE) {
287 raw_spin_unlock_irq(&ctx->lock);
290 if (ctx->is_active) {
291 raw_spin_unlock_irq(&ctx->lock);
294 func(event, NULL, ctx, data);
295 raw_spin_unlock_irq(&ctx->lock);
299 * Similar to event_function_call() + event_function(), but hard assumes IRQs
300 * are already disabled and we're on the right CPU.
302 static void event_function_local(struct perf_event *event, event_f func, void *data)
304 struct perf_event_context *ctx = event->ctx;
305 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
306 struct task_struct *task = READ_ONCE(ctx->task);
307 struct perf_event_context *task_ctx = NULL;
309 lockdep_assert_irqs_disabled();
312 if (task == TASK_TOMBSTONE)
318 perf_ctx_lock(cpuctx, task_ctx);
321 if (task == TASK_TOMBSTONE)
326 * We must be either inactive or active and the right task,
327 * otherwise we're screwed, since we cannot IPI to somewhere
330 if (ctx->is_active) {
331 if (WARN_ON_ONCE(task != current))
334 if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
338 WARN_ON_ONCE(&cpuctx->ctx != ctx);
341 func(event, cpuctx, ctx, data);
343 perf_ctx_unlock(cpuctx, task_ctx);
346 #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
347 PERF_FLAG_FD_OUTPUT |\
348 PERF_FLAG_PID_CGROUP |\
349 PERF_FLAG_FD_CLOEXEC)
352 * branch priv levels that need permission checks
354 #define PERF_SAMPLE_BRANCH_PERM_PLM \
355 (PERF_SAMPLE_BRANCH_KERNEL |\
356 PERF_SAMPLE_BRANCH_HV)
359 EVENT_FLEXIBLE = 0x1,
362 /* see ctx_resched() for details */
364 EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
368 * perf_sched_events : >0 events exist
369 * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
372 static void perf_sched_delayed(struct work_struct *work);
373 DEFINE_STATIC_KEY_FALSE(perf_sched_events);
374 static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
375 static DEFINE_MUTEX(perf_sched_mutex);
376 static atomic_t perf_sched_count;
378 static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
379 static DEFINE_PER_CPU(int, perf_sched_cb_usages);
380 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
382 static atomic_t nr_mmap_events __read_mostly;
383 static atomic_t nr_comm_events __read_mostly;
384 static atomic_t nr_namespaces_events __read_mostly;
385 static atomic_t nr_task_events __read_mostly;
386 static atomic_t nr_freq_events __read_mostly;
387 static atomic_t nr_switch_events __read_mostly;
389 static LIST_HEAD(pmus);
390 static DEFINE_MUTEX(pmus_lock);
391 static struct srcu_struct pmus_srcu;
392 static cpumask_var_t perf_online_mask;
395 * perf event paranoia level:
396 * -1 - not paranoid at all
397 * 0 - disallow raw tracepoint access for unpriv
398 * 1 - disallow cpu events for unpriv
399 * 2 - disallow kernel profiling for unpriv
401 int sysctl_perf_event_paranoid __read_mostly = 2;
403 /* Minimum for 512 kiB + 1 user control page */
404 int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
407 * max perf event sample rate
409 #define DEFAULT_MAX_SAMPLE_RATE 100000
410 #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
411 #define DEFAULT_CPU_TIME_MAX_PERCENT 25
413 int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
415 static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
416 static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
418 static int perf_sample_allowed_ns __read_mostly =
419 DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
421 static void update_perf_cpu_limits(void)
423 u64 tmp = perf_sample_period_ns;
425 tmp *= sysctl_perf_cpu_time_max_percent;
426 tmp = div_u64(tmp, 100);
430 WRITE_ONCE(perf_sample_allowed_ns, tmp);
433 static bool perf_rotate_context(struct perf_cpu_context *cpuctx);
435 int perf_proc_update_handler(struct ctl_table *table, int write,
436 void __user *buffer, size_t *lenp,
440 int perf_cpu = sysctl_perf_cpu_time_max_percent;
442 * If throttling is disabled don't allow the write:
444 if (write && (perf_cpu == 100 || perf_cpu == 0))
447 ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
451 max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
452 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
453 update_perf_cpu_limits();
458 int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
460 int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
461 void __user *buffer, size_t *lenp,
464 int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
469 if (sysctl_perf_cpu_time_max_percent == 100 ||
470 sysctl_perf_cpu_time_max_percent == 0) {
472 "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
473 WRITE_ONCE(perf_sample_allowed_ns, 0);
475 update_perf_cpu_limits();
482 * perf samples are done in some very critical code paths (NMIs).
483 * If they take too much CPU time, the system can lock up and not
484 * get any real work done. This will drop the sample rate when
485 * we detect that events are taking too long.
487 #define NR_ACCUMULATED_SAMPLES 128
488 static DEFINE_PER_CPU(u64, running_sample_length);
490 static u64 __report_avg;
491 static u64 __report_allowed;
493 static void perf_duration_warn(struct irq_work *w)
495 printk_ratelimited(KERN_INFO
496 "perf: interrupt took too long (%lld > %lld), lowering "
497 "kernel.perf_event_max_sample_rate to %d\n",
498 __report_avg, __report_allowed,
499 sysctl_perf_event_sample_rate);
502 static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
504 void perf_sample_event_took(u64 sample_len_ns)
506 u64 max_len = READ_ONCE(perf_sample_allowed_ns);
514 /* Decay the counter by 1 average sample. */
515 running_len = __this_cpu_read(running_sample_length);
516 running_len -= running_len/NR_ACCUMULATED_SAMPLES;
517 running_len += sample_len_ns;
518 __this_cpu_write(running_sample_length, running_len);
521 * Note: this will be biased artifically low until we have
522 * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
523 * from having to maintain a count.
525 avg_len = running_len/NR_ACCUMULATED_SAMPLES;
526 if (avg_len <= max_len)
529 __report_avg = avg_len;
530 __report_allowed = max_len;
533 * Compute a throttle threshold 25% below the current duration.
535 avg_len += avg_len / 4;
536 max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
542 WRITE_ONCE(perf_sample_allowed_ns, avg_len);
543 WRITE_ONCE(max_samples_per_tick, max);
545 sysctl_perf_event_sample_rate = max * HZ;
546 perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
548 if (!irq_work_queue(&perf_duration_work)) {
549 early_printk("perf: interrupt took too long (%lld > %lld), lowering "
550 "kernel.perf_event_max_sample_rate to %d\n",
551 __report_avg, __report_allowed,
552 sysctl_perf_event_sample_rate);
556 static atomic64_t perf_event_id;
558 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
559 enum event_type_t event_type);
561 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
562 enum event_type_t event_type,
563 struct task_struct *task);
565 static void update_context_time(struct perf_event_context *ctx);
566 static u64 perf_event_time(struct perf_event *event);
568 void __weak perf_event_print_debug(void) { }
570 extern __weak const char *perf_pmu_name(void)
575 static inline u64 perf_clock(void)
577 return local_clock();
580 static inline u64 perf_event_clock(struct perf_event *event)
582 return event->clock();
586 * State based event timekeeping...
588 * The basic idea is to use event->state to determine which (if any) time
589 * fields to increment with the current delta. This means we only need to
590 * update timestamps when we change state or when they are explicitly requested
593 * Event groups make things a little more complicated, but not terribly so. The
594 * rules for a group are that if the group leader is OFF the entire group is
595 * OFF, irrespecive of what the group member states are. This results in
596 * __perf_effective_state().
598 * A futher ramification is that when a group leader flips between OFF and
599 * !OFF, we need to update all group member times.
602 * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
603 * need to make sure the relevant context time is updated before we try and
604 * update our timestamps.
607 static __always_inline enum perf_event_state
608 __perf_effective_state(struct perf_event *event)
610 struct perf_event *leader = event->group_leader;
612 if (leader->state <= PERF_EVENT_STATE_OFF)
613 return leader->state;
618 static __always_inline void
619 __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
621 enum perf_event_state state = __perf_effective_state(event);
622 u64 delta = now - event->tstamp;
624 *enabled = event->total_time_enabled;
625 if (state >= PERF_EVENT_STATE_INACTIVE)
628 *running = event->total_time_running;
629 if (state >= PERF_EVENT_STATE_ACTIVE)
633 static void perf_event_update_time(struct perf_event *event)
635 u64 now = perf_event_time(event);
637 __perf_update_times(event, now, &event->total_time_enabled,
638 &event->total_time_running);
642 static void perf_event_update_sibling_time(struct perf_event *leader)
644 struct perf_event *sibling;
646 for_each_sibling_event(sibling, leader)
647 perf_event_update_time(sibling);
651 perf_event_set_state(struct perf_event *event, enum perf_event_state state)
653 if (event->state == state)
656 perf_event_update_time(event);
658 * If a group leader gets enabled/disabled all its siblings
661 if ((event->state < 0) ^ (state < 0))
662 perf_event_update_sibling_time(event);
664 WRITE_ONCE(event->state, state);
667 #ifdef CONFIG_CGROUP_PERF
670 perf_cgroup_match(struct perf_event *event)
672 struct perf_event_context *ctx = event->ctx;
673 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
675 /* @event doesn't care about cgroup */
679 /* wants specific cgroup scope but @cpuctx isn't associated with any */
684 * Cgroup scoping is recursive. An event enabled for a cgroup is
685 * also enabled for all its descendant cgroups. If @cpuctx's
686 * cgroup is a descendant of @event's (the test covers identity
687 * case), it's a match.
689 return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
690 event->cgrp->css.cgroup);
693 static inline void perf_detach_cgroup(struct perf_event *event)
695 css_put(&event->cgrp->css);
699 static inline int is_cgroup_event(struct perf_event *event)
701 return event->cgrp != NULL;
704 static inline u64 perf_cgroup_event_time(struct perf_event *event)
706 struct perf_cgroup_info *t;
708 t = per_cpu_ptr(event->cgrp->info, event->cpu);
712 static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
714 struct perf_cgroup_info *info;
719 info = this_cpu_ptr(cgrp->info);
721 info->time += now - info->timestamp;
722 info->timestamp = now;
725 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
727 struct perf_cgroup *cgrp = cpuctx->cgrp;
728 struct cgroup_subsys_state *css;
731 for (css = &cgrp->css; css; css = css->parent) {
732 cgrp = container_of(css, struct perf_cgroup, css);
733 __update_cgrp_time(cgrp);
738 static inline void update_cgrp_time_from_event(struct perf_event *event)
740 struct perf_cgroup *cgrp;
743 * ensure we access cgroup data only when needed and
744 * when we know the cgroup is pinned (css_get)
746 if (!is_cgroup_event(event))
749 cgrp = perf_cgroup_from_task(current, event->ctx);
751 * Do not update time when cgroup is not active
753 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
754 __update_cgrp_time(event->cgrp);
758 perf_cgroup_set_timestamp(struct task_struct *task,
759 struct perf_event_context *ctx)
761 struct perf_cgroup *cgrp;
762 struct perf_cgroup_info *info;
763 struct cgroup_subsys_state *css;
766 * ctx->lock held by caller
767 * ensure we do not access cgroup data
768 * unless we have the cgroup pinned (css_get)
770 if (!task || !ctx->nr_cgroups)
773 cgrp = perf_cgroup_from_task(task, ctx);
775 for (css = &cgrp->css; css; css = css->parent) {
776 cgrp = container_of(css, struct perf_cgroup, css);
777 info = this_cpu_ptr(cgrp->info);
778 info->timestamp = ctx->timestamp;
782 static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
784 #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
785 #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
788 * reschedule events based on the cgroup constraint of task.
790 * mode SWOUT : schedule out everything
791 * mode SWIN : schedule in based on cgroup for next
793 static void perf_cgroup_switch(struct task_struct *task, int mode)
795 struct perf_cpu_context *cpuctx;
796 struct list_head *list;
800 * Disable interrupts and preemption to avoid this CPU's
801 * cgrp_cpuctx_entry to change under us.
803 local_irq_save(flags);
805 list = this_cpu_ptr(&cgrp_cpuctx_list);
806 list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
807 WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
809 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
810 perf_pmu_disable(cpuctx->ctx.pmu);
812 if (mode & PERF_CGROUP_SWOUT) {
813 cpu_ctx_sched_out(cpuctx, EVENT_ALL);
815 * must not be done before ctxswout due
816 * to event_filter_match() in event_sched_out()
821 if (mode & PERF_CGROUP_SWIN) {
822 WARN_ON_ONCE(cpuctx->cgrp);
824 * set cgrp before ctxsw in to allow
825 * event_filter_match() to not have to pass
827 * we pass the cpuctx->ctx to perf_cgroup_from_task()
828 * because cgorup events are only per-cpu
830 cpuctx->cgrp = perf_cgroup_from_task(task,
832 cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
834 perf_pmu_enable(cpuctx->ctx.pmu);
835 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
838 local_irq_restore(flags);
841 static inline void perf_cgroup_sched_out(struct task_struct *task,
842 struct task_struct *next)
844 struct perf_cgroup *cgrp1;
845 struct perf_cgroup *cgrp2 = NULL;
849 * we come here when we know perf_cgroup_events > 0
850 * we do not need to pass the ctx here because we know
851 * we are holding the rcu lock
853 cgrp1 = perf_cgroup_from_task(task, NULL);
854 cgrp2 = perf_cgroup_from_task(next, NULL);
857 * only schedule out current cgroup events if we know
858 * that we are switching to a different cgroup. Otherwise,
859 * do no touch the cgroup events.
862 perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
867 static inline void perf_cgroup_sched_in(struct task_struct *prev,
868 struct task_struct *task)
870 struct perf_cgroup *cgrp1;
871 struct perf_cgroup *cgrp2 = NULL;
875 * we come here when we know perf_cgroup_events > 0
876 * we do not need to pass the ctx here because we know
877 * we are holding the rcu lock
879 cgrp1 = perf_cgroup_from_task(task, NULL);
880 cgrp2 = perf_cgroup_from_task(prev, NULL);
883 * only need to schedule in cgroup events if we are changing
884 * cgroup during ctxsw. Cgroup events were not scheduled
885 * out of ctxsw out if that was not the case.
888 perf_cgroup_switch(task, PERF_CGROUP_SWIN);
893 static inline int perf_cgroup_connect(int fd, struct perf_event *event,
894 struct perf_event_attr *attr,
895 struct perf_event *group_leader)
897 struct perf_cgroup *cgrp;
898 struct cgroup_subsys_state *css;
899 struct fd f = fdget(fd);
905 css = css_tryget_online_from_dir(f.file->f_path.dentry,
906 &perf_event_cgrp_subsys);
912 cgrp = container_of(css, struct perf_cgroup, css);
916 * all events in a group must monitor
917 * the same cgroup because a task belongs
918 * to only one perf cgroup at a time
920 if (group_leader && group_leader->cgrp != cgrp) {
921 perf_detach_cgroup(event);
930 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
932 struct perf_cgroup_info *t;
933 t = per_cpu_ptr(event->cgrp->info, event->cpu);
934 event->shadow_ctx_time = now - t->timestamp;
938 * Update cpuctx->cgrp so that it is set when first cgroup event is added and
939 * cleared when last cgroup event is removed.
942 list_update_cgroup_event(struct perf_event *event,
943 struct perf_event_context *ctx, bool add)
945 struct perf_cpu_context *cpuctx;
946 struct list_head *cpuctx_entry;
948 if (!is_cgroup_event(event))
952 * Because cgroup events are always per-cpu events,
953 * this will always be called from the right CPU.
955 cpuctx = __get_cpu_context(ctx);
958 * Since setting cpuctx->cgrp is conditional on the current @cgrp
959 * matching the event's cgroup, we must do this for every new event,
960 * because if the first would mismatch, the second would not try again
961 * and we would leave cpuctx->cgrp unset.
963 if (add && !cpuctx->cgrp) {
964 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
966 if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
970 if (add && ctx->nr_cgroups++)
972 else if (!add && --ctx->nr_cgroups)
975 /* no cgroup running */
979 cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
981 list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
983 list_del(cpuctx_entry);
986 #else /* !CONFIG_CGROUP_PERF */
989 perf_cgroup_match(struct perf_event *event)
994 static inline void perf_detach_cgroup(struct perf_event *event)
997 static inline int is_cgroup_event(struct perf_event *event)
1002 static inline void update_cgrp_time_from_event(struct perf_event *event)
1006 static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
1010 static inline void perf_cgroup_sched_out(struct task_struct *task,
1011 struct task_struct *next)
1015 static inline void perf_cgroup_sched_in(struct task_struct *prev,
1016 struct task_struct *task)
1020 static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1021 struct perf_event_attr *attr,
1022 struct perf_event *group_leader)
1028 perf_cgroup_set_timestamp(struct task_struct *task,
1029 struct perf_event_context *ctx)
1034 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1039 perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1043 static inline u64 perf_cgroup_event_time(struct perf_event *event)
1049 list_update_cgroup_event(struct perf_event *event,
1050 struct perf_event_context *ctx, bool add)
1057 * set default to be dependent on timer tick just
1058 * like original code
1060 #define PERF_CPU_HRTIMER (1000 / HZ)
1062 * function must be called with interrupts disabled
1064 static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1066 struct perf_cpu_context *cpuctx;
1069 lockdep_assert_irqs_disabled();
1071 cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1072 rotations = perf_rotate_context(cpuctx);
1074 raw_spin_lock(&cpuctx->hrtimer_lock);
1076 hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1078 cpuctx->hrtimer_active = 0;
1079 raw_spin_unlock(&cpuctx->hrtimer_lock);
1081 return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1084 static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1086 struct hrtimer *timer = &cpuctx->hrtimer;
1087 struct pmu *pmu = cpuctx->ctx.pmu;
1090 /* no multiplexing needed for SW PMU */
1091 if (pmu->task_ctx_nr == perf_sw_context)
1095 * check default is sane, if not set then force to
1096 * default interval (1/tick)
1098 interval = pmu->hrtimer_interval_ms;
1100 interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1102 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1104 raw_spin_lock_init(&cpuctx->hrtimer_lock);
1105 hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
1106 timer->function = perf_mux_hrtimer_handler;
1109 static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1111 struct hrtimer *timer = &cpuctx->hrtimer;
1112 struct pmu *pmu = cpuctx->ctx.pmu;
1113 unsigned long flags;
1115 /* not for SW PMU */
1116 if (pmu->task_ctx_nr == perf_sw_context)
1119 raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1120 if (!cpuctx->hrtimer_active) {
1121 cpuctx->hrtimer_active = 1;
1122 hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1123 hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
1125 raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1130 void perf_pmu_disable(struct pmu *pmu)
1132 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1134 pmu->pmu_disable(pmu);
1137 void perf_pmu_enable(struct pmu *pmu)
1139 int *count = this_cpu_ptr(pmu->pmu_disable_count);
1141 pmu->pmu_enable(pmu);
1144 static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1147 * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1148 * perf_event_task_tick() are fully serialized because they're strictly cpu
1149 * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1150 * disabled, while perf_event_task_tick is called from IRQ context.
1152 static void perf_event_ctx_activate(struct perf_event_context *ctx)
1154 struct list_head *head = this_cpu_ptr(&active_ctx_list);
1156 lockdep_assert_irqs_disabled();
1158 WARN_ON(!list_empty(&ctx->active_ctx_list));
1160 list_add(&ctx->active_ctx_list, head);
1163 static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1165 lockdep_assert_irqs_disabled();
1167 WARN_ON(list_empty(&ctx->active_ctx_list));
1169 list_del_init(&ctx->active_ctx_list);
1172 static void get_ctx(struct perf_event_context *ctx)
1174 WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
1177 static void free_ctx(struct rcu_head *head)
1179 struct perf_event_context *ctx;
1181 ctx = container_of(head, struct perf_event_context, rcu_head);
1182 kfree(ctx->task_ctx_data);
1186 static void put_ctx(struct perf_event_context *ctx)
1188 if (atomic_dec_and_test(&ctx->refcount)) {
1189 if (ctx->parent_ctx)
1190 put_ctx(ctx->parent_ctx);
1191 if (ctx->task && ctx->task != TASK_TOMBSTONE)
1192 put_task_struct(ctx->task);
1193 call_rcu(&ctx->rcu_head, free_ctx);
1198 * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1199 * perf_pmu_migrate_context() we need some magic.
1201 * Those places that change perf_event::ctx will hold both
1202 * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1204 * Lock ordering is by mutex address. There are two other sites where
1205 * perf_event_context::mutex nests and those are:
1207 * - perf_event_exit_task_context() [ child , 0 ]
1208 * perf_event_exit_event()
1209 * put_event() [ parent, 1 ]
1211 * - perf_event_init_context() [ parent, 0 ]
1212 * inherit_task_group()
1215 * perf_event_alloc()
1217 * perf_try_init_event() [ child , 1 ]
1219 * While it appears there is an obvious deadlock here -- the parent and child
1220 * nesting levels are inverted between the two. This is in fact safe because
1221 * life-time rules separate them. That is an exiting task cannot fork, and a
1222 * spawning task cannot (yet) exit.
1224 * But remember that that these are parent<->child context relations, and
1225 * migration does not affect children, therefore these two orderings should not
1228 * The change in perf_event::ctx does not affect children (as claimed above)
1229 * because the sys_perf_event_open() case will install a new event and break
1230 * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1231 * concerned with cpuctx and that doesn't have children.
1233 * The places that change perf_event::ctx will issue:
1235 * perf_remove_from_context();
1236 * synchronize_rcu();
1237 * perf_install_in_context();
1239 * to affect the change. The remove_from_context() + synchronize_rcu() should
1240 * quiesce the event, after which we can install it in the new location. This
1241 * means that only external vectors (perf_fops, prctl) can perturb the event
1242 * while in transit. Therefore all such accessors should also acquire
1243 * perf_event_context::mutex to serialize against this.
1245 * However; because event->ctx can change while we're waiting to acquire
1246 * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1251 * task_struct::perf_event_mutex
1252 * perf_event_context::mutex
1253 * perf_event::child_mutex;
1254 * perf_event_context::lock
1255 * perf_event::mmap_mutex
1260 * cpuctx->mutex / perf_event_context::mutex
1262 static struct perf_event_context *
1263 perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1265 struct perf_event_context *ctx;
1269 ctx = READ_ONCE(event->ctx);
1270 if (!atomic_inc_not_zero(&ctx->refcount)) {
1276 mutex_lock_nested(&ctx->mutex, nesting);
1277 if (event->ctx != ctx) {
1278 mutex_unlock(&ctx->mutex);
1286 static inline struct perf_event_context *
1287 perf_event_ctx_lock(struct perf_event *event)
1289 return perf_event_ctx_lock_nested(event, 0);
1292 static void perf_event_ctx_unlock(struct perf_event *event,
1293 struct perf_event_context *ctx)
1295 mutex_unlock(&ctx->mutex);
1300 * This must be done under the ctx->lock, such as to serialize against
1301 * context_equiv(), therefore we cannot call put_ctx() since that might end up
1302 * calling scheduler related locks and ctx->lock nests inside those.
1304 static __must_check struct perf_event_context *
1305 unclone_ctx(struct perf_event_context *ctx)
1307 struct perf_event_context *parent_ctx = ctx->parent_ctx;
1309 lockdep_assert_held(&ctx->lock);
1312 ctx->parent_ctx = NULL;
1318 static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1323 * only top level events have the pid namespace they were created in
1326 event = event->parent;
1328 nr = __task_pid_nr_ns(p, type, event->ns);
1329 /* avoid -1 if it is idle thread or runs in another ns */
1330 if (!nr && !pid_alive(p))
1335 static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1337 return perf_event_pid_type(event, p, PIDTYPE_TGID);
1340 static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1342 return perf_event_pid_type(event, p, PIDTYPE_PID);
1346 * If we inherit events we want to return the parent event id
1349 static u64 primary_event_id(struct perf_event *event)
1354 id = event->parent->id;
1360 * Get the perf_event_context for a task and lock it.
1362 * This has to cope with with the fact that until it is locked,
1363 * the context could get moved to another task.
1365 static struct perf_event_context *
1366 perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1368 struct perf_event_context *ctx;
1372 * One of the few rules of preemptible RCU is that one cannot do
1373 * rcu_read_unlock() while holding a scheduler (or nested) lock when
1374 * part of the read side critical section was irqs-enabled -- see
1375 * rcu_read_unlock_special().
1377 * Since ctx->lock nests under rq->lock we must ensure the entire read
1378 * side critical section has interrupts disabled.
1380 local_irq_save(*flags);
1382 ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1385 * If this context is a clone of another, it might
1386 * get swapped for another underneath us by
1387 * perf_event_task_sched_out, though the
1388 * rcu_read_lock() protects us from any context
1389 * getting freed. Lock the context and check if it
1390 * got swapped before we could get the lock, and retry
1391 * if so. If we locked the right context, then it
1392 * can't get swapped on us any more.
1394 raw_spin_lock(&ctx->lock);
1395 if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1396 raw_spin_unlock(&ctx->lock);
1398 local_irq_restore(*flags);
1402 if (ctx->task == TASK_TOMBSTONE ||
1403 !atomic_inc_not_zero(&ctx->refcount)) {
1404 raw_spin_unlock(&ctx->lock);
1407 WARN_ON_ONCE(ctx->task != task);
1412 local_irq_restore(*flags);
1417 * Get the context for a task and increment its pin_count so it
1418 * can't get swapped to another task. This also increments its
1419 * reference count so that the context can't get freed.
1421 static struct perf_event_context *
1422 perf_pin_task_context(struct task_struct *task, int ctxn)
1424 struct perf_event_context *ctx;
1425 unsigned long flags;
1427 ctx = perf_lock_task_context(task, ctxn, &flags);
1430 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1435 static void perf_unpin_context(struct perf_event_context *ctx)
1437 unsigned long flags;
1439 raw_spin_lock_irqsave(&ctx->lock, flags);
1441 raw_spin_unlock_irqrestore(&ctx->lock, flags);
1445 * Update the record of the current time in a context.
1447 static void update_context_time(struct perf_event_context *ctx)
1449 u64 now = perf_clock();
1451 ctx->time += now - ctx->timestamp;
1452 ctx->timestamp = now;
1455 static u64 perf_event_time(struct perf_event *event)
1457 struct perf_event_context *ctx = event->ctx;
1459 if (is_cgroup_event(event))
1460 return perf_cgroup_event_time(event);
1462 return ctx ? ctx->time : 0;
1465 static enum event_type_t get_event_type(struct perf_event *event)
1467 struct perf_event_context *ctx = event->ctx;
1468 enum event_type_t event_type;
1470 lockdep_assert_held(&ctx->lock);
1473 * It's 'group type', really, because if our group leader is
1474 * pinned, so are we.
1476 if (event->group_leader != event)
1477 event = event->group_leader;
1479 event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1481 event_type |= EVENT_CPU;
1487 * Helper function to initialize event group nodes.
1489 static void init_event_group(struct perf_event *event)
1491 RB_CLEAR_NODE(&event->group_node);
1492 event->group_index = 0;
1496 * Extract pinned or flexible groups from the context
1497 * based on event attrs bits.
1499 static struct perf_event_groups *
1500 get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1502 if (event->attr.pinned)
1503 return &ctx->pinned_groups;
1505 return &ctx->flexible_groups;
1509 * Helper function to initializes perf_event_group trees.
1511 static void perf_event_groups_init(struct perf_event_groups *groups)
1513 groups->tree = RB_ROOT;
1518 * Compare function for event groups;
1520 * Implements complex key that first sorts by CPU and then by virtual index
1521 * which provides ordering when rotating groups for the same CPU.
1524 perf_event_groups_less(struct perf_event *left, struct perf_event *right)
1526 if (left->cpu < right->cpu)
1528 if (left->cpu > right->cpu)
1531 if (left->group_index < right->group_index)
1533 if (left->group_index > right->group_index)
1540 * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1541 * key (see perf_event_groups_less). This places it last inside the CPU
1545 perf_event_groups_insert(struct perf_event_groups *groups,
1546 struct perf_event *event)
1548 struct perf_event *node_event;
1549 struct rb_node *parent;
1550 struct rb_node **node;
1552 event->group_index = ++groups->index;
1554 node = &groups->tree.rb_node;
1559 node_event = container_of(*node, struct perf_event, group_node);
1561 if (perf_event_groups_less(event, node_event))
1562 node = &parent->rb_left;
1564 node = &parent->rb_right;
1567 rb_link_node(&event->group_node, parent, node);
1568 rb_insert_color(&event->group_node, &groups->tree);
1572 * Helper function to insert event into the pinned or flexible groups.
1575 add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1577 struct perf_event_groups *groups;
1579 groups = get_event_groups(event, ctx);
1580 perf_event_groups_insert(groups, event);
1584 * Delete a group from a tree.
1587 perf_event_groups_delete(struct perf_event_groups *groups,
1588 struct perf_event *event)
1590 WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1591 RB_EMPTY_ROOT(&groups->tree));
1593 rb_erase(&event->group_node, &groups->tree);
1594 init_event_group(event);
1598 * Helper function to delete event from its groups.
1601 del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1603 struct perf_event_groups *groups;
1605 groups = get_event_groups(event, ctx);
1606 perf_event_groups_delete(groups, event);
1610 * Get the leftmost event in the @cpu subtree.
1612 static struct perf_event *
1613 perf_event_groups_first(struct perf_event_groups *groups, int cpu)
1615 struct perf_event *node_event = NULL, *match = NULL;
1616 struct rb_node *node = groups->tree.rb_node;
1619 node_event = container_of(node, struct perf_event, group_node);
1621 if (cpu < node_event->cpu) {
1622 node = node->rb_left;
1623 } else if (cpu > node_event->cpu) {
1624 node = node->rb_right;
1627 node = node->rb_left;
1635 * Like rb_entry_next_safe() for the @cpu subtree.
1637 static struct perf_event *
1638 perf_event_groups_next(struct perf_event *event)
1640 struct perf_event *next;
1642 next = rb_entry_safe(rb_next(&event->group_node), typeof(*event), group_node);
1643 if (next && next->cpu == event->cpu)
1650 * Iterate through the whole groups tree.
1652 #define perf_event_groups_for_each(event, groups) \
1653 for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1654 typeof(*event), group_node); event; \
1655 event = rb_entry_safe(rb_next(&event->group_node), \
1656 typeof(*event), group_node))
1659 * Add an event from the lists for its context.
1660 * Must be called with ctx->mutex and ctx->lock held.
1663 list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1665 lockdep_assert_held(&ctx->lock);
1667 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1668 event->attach_state |= PERF_ATTACH_CONTEXT;
1670 event->tstamp = perf_event_time(event);
1673 * If we're a stand alone event or group leader, we go to the context
1674 * list, group events are kept attached to the group so that
1675 * perf_group_detach can, at all times, locate all siblings.
1677 if (event->group_leader == event) {
1678 event->group_caps = event->event_caps;
1679 add_event_to_groups(event, ctx);
1682 list_update_cgroup_event(event, ctx, true);
1684 list_add_rcu(&event->event_entry, &ctx->event_list);
1686 if (event->attr.inherit_stat)
1693 * Initialize event state based on the perf_event_attr::disabled.
1695 static inline void perf_event__state_init(struct perf_event *event)
1697 event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1698 PERF_EVENT_STATE_INACTIVE;
1701 static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1703 int entry = sizeof(u64); /* value */
1707 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1708 size += sizeof(u64);
1710 if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1711 size += sizeof(u64);
1713 if (event->attr.read_format & PERF_FORMAT_ID)
1714 entry += sizeof(u64);
1716 if (event->attr.read_format & PERF_FORMAT_GROUP) {
1718 size += sizeof(u64);
1722 event->read_size = size;
1725 static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1727 struct perf_sample_data *data;
1730 if (sample_type & PERF_SAMPLE_IP)
1731 size += sizeof(data->ip);
1733 if (sample_type & PERF_SAMPLE_ADDR)
1734 size += sizeof(data->addr);
1736 if (sample_type & PERF_SAMPLE_PERIOD)
1737 size += sizeof(data->period);
1739 if (sample_type & PERF_SAMPLE_WEIGHT)
1740 size += sizeof(data->weight);
1742 if (sample_type & PERF_SAMPLE_READ)
1743 size += event->read_size;
1745 if (sample_type & PERF_SAMPLE_DATA_SRC)
1746 size += sizeof(data->data_src.val);
1748 if (sample_type & PERF_SAMPLE_TRANSACTION)
1749 size += sizeof(data->txn);
1751 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1752 size += sizeof(data->phys_addr);
1754 event->header_size = size;
1758 * Called at perf_event creation and when events are attached/detached from a
1761 static void perf_event__header_size(struct perf_event *event)
1763 __perf_event_read_size(event,
1764 event->group_leader->nr_siblings);
1765 __perf_event_header_size(event, event->attr.sample_type);
1768 static void perf_event__id_header_size(struct perf_event *event)
1770 struct perf_sample_data *data;
1771 u64 sample_type = event->attr.sample_type;
1774 if (sample_type & PERF_SAMPLE_TID)
1775 size += sizeof(data->tid_entry);
1777 if (sample_type & PERF_SAMPLE_TIME)
1778 size += sizeof(data->time);
1780 if (sample_type & PERF_SAMPLE_IDENTIFIER)
1781 size += sizeof(data->id);
1783 if (sample_type & PERF_SAMPLE_ID)
1784 size += sizeof(data->id);
1786 if (sample_type & PERF_SAMPLE_STREAM_ID)
1787 size += sizeof(data->stream_id);
1789 if (sample_type & PERF_SAMPLE_CPU)
1790 size += sizeof(data->cpu_entry);
1792 event->id_header_size = size;
1795 static bool perf_event_validate_size(struct perf_event *event)
1798 * The values computed here will be over-written when we actually
1801 __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1802 __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1803 perf_event__id_header_size(event);
1806 * Sum the lot; should not exceed the 64k limit we have on records.
1807 * Conservative limit to allow for callchains and other variable fields.
1809 if (event->read_size + event->header_size +
1810 event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1816 static void perf_group_attach(struct perf_event *event)
1818 struct perf_event *group_leader = event->group_leader, *pos;
1820 lockdep_assert_held(&event->ctx->lock);
1823 * We can have double attach due to group movement in perf_event_open.
1825 if (event->attach_state & PERF_ATTACH_GROUP)
1828 event->attach_state |= PERF_ATTACH_GROUP;
1830 if (group_leader == event)
1833 WARN_ON_ONCE(group_leader->ctx != event->ctx);
1835 group_leader->group_caps &= event->event_caps;
1837 list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1838 group_leader->nr_siblings++;
1840 perf_event__header_size(group_leader);
1842 for_each_sibling_event(pos, group_leader)
1843 perf_event__header_size(pos);
1847 * Remove an event from the lists for its context.
1848 * Must be called with ctx->mutex and ctx->lock held.
1851 list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1853 WARN_ON_ONCE(event->ctx != ctx);
1854 lockdep_assert_held(&ctx->lock);
1857 * We can have double detach due to exit/hot-unplug + close.
1859 if (!(event->attach_state & PERF_ATTACH_CONTEXT))
1862 event->attach_state &= ~PERF_ATTACH_CONTEXT;
1864 list_update_cgroup_event(event, ctx, false);
1867 if (event->attr.inherit_stat)
1870 list_del_rcu(&event->event_entry);
1872 if (event->group_leader == event)
1873 del_event_from_groups(event, ctx);
1876 * If event was in error state, then keep it
1877 * that way, otherwise bogus counts will be
1878 * returned on read(). The only way to get out
1879 * of error state is by explicit re-enabling
1882 if (event->state > PERF_EVENT_STATE_OFF)
1883 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
1888 static void perf_group_detach(struct perf_event *event)
1890 struct perf_event *sibling, *tmp;
1891 struct perf_event_context *ctx = event->ctx;
1893 lockdep_assert_held(&ctx->lock);
1896 * We can have double detach due to exit/hot-unplug + close.
1898 if (!(event->attach_state & PERF_ATTACH_GROUP))
1901 event->attach_state &= ~PERF_ATTACH_GROUP;
1904 * If this is a sibling, remove it from its group.
1906 if (event->group_leader != event) {
1907 list_del_init(&event->sibling_list);
1908 event->group_leader->nr_siblings--;
1913 * If this was a group event with sibling events then
1914 * upgrade the siblings to singleton events by adding them
1915 * to whatever list we are on.
1917 list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
1919 sibling->group_leader = sibling;
1920 list_del_init(&sibling->sibling_list);
1922 /* Inherit group flags from the previous leader */
1923 sibling->group_caps = event->group_caps;
1925 if (!RB_EMPTY_NODE(&event->group_node)) {
1926 add_event_to_groups(sibling, event->ctx);
1928 if (sibling->state == PERF_EVENT_STATE_ACTIVE) {
1929 struct list_head *list = sibling->attr.pinned ?
1930 &ctx->pinned_active : &ctx->flexible_active;
1932 list_add_tail(&sibling->active_list, list);
1936 WARN_ON_ONCE(sibling->ctx != event->ctx);
1940 perf_event__header_size(event->group_leader);
1942 for_each_sibling_event(tmp, event->group_leader)
1943 perf_event__header_size(tmp);
1946 static bool is_orphaned_event(struct perf_event *event)
1948 return event->state == PERF_EVENT_STATE_DEAD;
1951 static inline int __pmu_filter_match(struct perf_event *event)
1953 struct pmu *pmu = event->pmu;
1954 return pmu->filter_match ? pmu->filter_match(event) : 1;
1958 * Check whether we should attempt to schedule an event group based on
1959 * PMU-specific filtering. An event group can consist of HW and SW events,
1960 * potentially with a SW leader, so we must check all the filters, to
1961 * determine whether a group is schedulable:
1963 static inline int pmu_filter_match(struct perf_event *event)
1965 struct perf_event *sibling;
1967 if (!__pmu_filter_match(event))
1970 for_each_sibling_event(sibling, event) {
1971 if (!__pmu_filter_match(sibling))
1979 event_filter_match(struct perf_event *event)
1981 return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
1982 perf_cgroup_match(event) && pmu_filter_match(event);
1986 event_sched_out(struct perf_event *event,
1987 struct perf_cpu_context *cpuctx,
1988 struct perf_event_context *ctx)
1990 enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
1992 WARN_ON_ONCE(event->ctx != ctx);
1993 lockdep_assert_held(&ctx->lock);
1995 if (event->state != PERF_EVENT_STATE_ACTIVE)
1999 * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2000 * we can schedule events _OUT_ individually through things like
2001 * __perf_remove_from_context().
2003 list_del_init(&event->active_list);
2005 perf_pmu_disable(event->pmu);
2007 event->pmu->del(event, 0);
2010 if (event->pending_disable) {
2011 event->pending_disable = 0;
2012 state = PERF_EVENT_STATE_OFF;
2014 perf_event_set_state(event, state);
2016 if (!is_software_event(event))
2017 cpuctx->active_oncpu--;
2018 if (!--ctx->nr_active)
2019 perf_event_ctx_deactivate(ctx);
2020 if (event->attr.freq && event->attr.sample_freq)
2022 if (event->attr.exclusive || !cpuctx->active_oncpu)
2023 cpuctx->exclusive = 0;
2025 perf_pmu_enable(event->pmu);
2029 group_sched_out(struct perf_event *group_event,
2030 struct perf_cpu_context *cpuctx,
2031 struct perf_event_context *ctx)
2033 struct perf_event *event;
2035 if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2038 perf_pmu_disable(ctx->pmu);
2040 event_sched_out(group_event, cpuctx, ctx);
2043 * Schedule out siblings (if any):
2045 for_each_sibling_event(event, group_event)
2046 event_sched_out(event, cpuctx, ctx);
2048 perf_pmu_enable(ctx->pmu);
2050 if (group_event->attr.exclusive)
2051 cpuctx->exclusive = 0;
2054 #define DETACH_GROUP 0x01UL
2057 * Cross CPU call to remove a performance event
2059 * We disable the event on the hardware level first. After that we
2060 * remove it from the context list.
2063 __perf_remove_from_context(struct perf_event *event,
2064 struct perf_cpu_context *cpuctx,
2065 struct perf_event_context *ctx,
2068 unsigned long flags = (unsigned long)info;
2070 if (ctx->is_active & EVENT_TIME) {
2071 update_context_time(ctx);
2072 update_cgrp_time_from_cpuctx(cpuctx);
2075 event_sched_out(event, cpuctx, ctx);
2076 if (flags & DETACH_GROUP)
2077 perf_group_detach(event);
2078 list_del_event(event, ctx);
2080 if (!ctx->nr_events && ctx->is_active) {
2083 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2084 cpuctx->task_ctx = NULL;
2090 * Remove the event from a task's (or a CPU's) list of events.
2092 * If event->ctx is a cloned context, callers must make sure that
2093 * every task struct that event->ctx->task could possibly point to
2094 * remains valid. This is OK when called from perf_release since
2095 * that only calls us on the top-level context, which can't be a clone.
2096 * When called from perf_event_exit_task, it's OK because the
2097 * context has been detached from its task.
2099 static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2101 struct perf_event_context *ctx = event->ctx;
2103 lockdep_assert_held(&ctx->mutex);
2105 event_function_call(event, __perf_remove_from_context, (void *)flags);
2108 * The above event_function_call() can NO-OP when it hits
2109 * TASK_TOMBSTONE. In that case we must already have been detached
2110 * from the context (by perf_event_exit_event()) but the grouping
2111 * might still be in-tact.
2113 WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
2114 if ((flags & DETACH_GROUP) &&
2115 (event->attach_state & PERF_ATTACH_GROUP)) {
2117 * Since in that case we cannot possibly be scheduled, simply
2120 raw_spin_lock_irq(&ctx->lock);
2121 perf_group_detach(event);
2122 raw_spin_unlock_irq(&ctx->lock);
2127 * Cross CPU call to disable a performance event
2129 static void __perf_event_disable(struct perf_event *event,
2130 struct perf_cpu_context *cpuctx,
2131 struct perf_event_context *ctx,
2134 if (event->state < PERF_EVENT_STATE_INACTIVE)
2137 if (ctx->is_active & EVENT_TIME) {
2138 update_context_time(ctx);
2139 update_cgrp_time_from_event(event);
2142 if (event == event->group_leader)
2143 group_sched_out(event, cpuctx, ctx);
2145 event_sched_out(event, cpuctx, ctx);
2147 perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2153 * If event->ctx is a cloned context, callers must make sure that
2154 * every task struct that event->ctx->task could possibly point to
2155 * remains valid. This condition is satisifed when called through
2156 * perf_event_for_each_child or perf_event_for_each because they
2157 * hold the top-level event's child_mutex, so any descendant that
2158 * goes to exit will block in perf_event_exit_event().
2160 * When called from perf_pending_event it's OK because event->ctx
2161 * is the current context on this CPU and preemption is disabled,
2162 * hence we can't get into perf_event_task_sched_out for this context.
2164 static void _perf_event_disable(struct perf_event *event)
2166 struct perf_event_context *ctx = event->ctx;
2168 raw_spin_lock_irq(&ctx->lock);
2169 if (event->state <= PERF_EVENT_STATE_OFF) {
2170 raw_spin_unlock_irq(&ctx->lock);
2173 raw_spin_unlock_irq(&ctx->lock);
2175 event_function_call(event, __perf_event_disable, NULL);
2178 void perf_event_disable_local(struct perf_event *event)
2180 event_function_local(event, __perf_event_disable, NULL);
2184 * Strictly speaking kernel users cannot create groups and therefore this
2185 * interface does not need the perf_event_ctx_lock() magic.
2187 void perf_event_disable(struct perf_event *event)
2189 struct perf_event_context *ctx;
2191 ctx = perf_event_ctx_lock(event);
2192 _perf_event_disable(event);
2193 perf_event_ctx_unlock(event, ctx);
2195 EXPORT_SYMBOL_GPL(perf_event_disable);
2197 void perf_event_disable_inatomic(struct perf_event *event)
2199 event->pending_disable = 1;
2200 irq_work_queue(&event->pending);
2203 static void perf_set_shadow_time(struct perf_event *event,
2204 struct perf_event_context *ctx)
2207 * use the correct time source for the time snapshot
2209 * We could get by without this by leveraging the
2210 * fact that to get to this function, the caller
2211 * has most likely already called update_context_time()
2212 * and update_cgrp_time_xx() and thus both timestamp
2213 * are identical (or very close). Given that tstamp is,
2214 * already adjusted for cgroup, we could say that:
2215 * tstamp - ctx->timestamp
2217 * tstamp - cgrp->timestamp.
2219 * Then, in perf_output_read(), the calculation would
2220 * work with no changes because:
2221 * - event is guaranteed scheduled in
2222 * - no scheduled out in between
2223 * - thus the timestamp would be the same
2225 * But this is a bit hairy.
2227 * So instead, we have an explicit cgroup call to remain
2228 * within the time time source all along. We believe it
2229 * is cleaner and simpler to understand.
2231 if (is_cgroup_event(event))
2232 perf_cgroup_set_shadow_time(event, event->tstamp);
2234 event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2237 #define MAX_INTERRUPTS (~0ULL)
2239 static void perf_log_throttle(struct perf_event *event, int enable);
2240 static void perf_log_itrace_start(struct perf_event *event);
2243 event_sched_in(struct perf_event *event,
2244 struct perf_cpu_context *cpuctx,
2245 struct perf_event_context *ctx)
2249 lockdep_assert_held(&ctx->lock);
2251 if (event->state <= PERF_EVENT_STATE_OFF)
2254 WRITE_ONCE(event->oncpu, smp_processor_id());
2256 * Order event::oncpu write to happen before the ACTIVE state is
2257 * visible. This allows perf_event_{stop,read}() to observe the correct
2258 * ->oncpu if it sees ACTIVE.
2261 perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2264 * Unthrottle events, since we scheduled we might have missed several
2265 * ticks already, also for a heavily scheduling task there is little
2266 * guarantee it'll get a tick in a timely manner.
2268 if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2269 perf_log_throttle(event, 1);
2270 event->hw.interrupts = 0;
2273 perf_pmu_disable(event->pmu);
2275 perf_set_shadow_time(event, ctx);
2277 perf_log_itrace_start(event);
2279 if (event->pmu->add(event, PERF_EF_START)) {
2280 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2286 if (!is_software_event(event))
2287 cpuctx->active_oncpu++;
2288 if (!ctx->nr_active++)
2289 perf_event_ctx_activate(ctx);
2290 if (event->attr.freq && event->attr.sample_freq)
2293 if (event->attr.exclusive)
2294 cpuctx->exclusive = 1;
2297 perf_pmu_enable(event->pmu);
2303 group_sched_in(struct perf_event *group_event,
2304 struct perf_cpu_context *cpuctx,
2305 struct perf_event_context *ctx)
2307 struct perf_event *event, *partial_group = NULL;
2308 struct pmu *pmu = ctx->pmu;
2310 if (group_event->state == PERF_EVENT_STATE_OFF)
2313 pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2315 if (event_sched_in(group_event, cpuctx, ctx)) {
2316 pmu->cancel_txn(pmu);
2317 perf_mux_hrtimer_restart(cpuctx);
2322 * Schedule in siblings as one group (if any):
2324 for_each_sibling_event(event, group_event) {
2325 if (event_sched_in(event, cpuctx, ctx)) {
2326 partial_group = event;
2331 if (!pmu->commit_txn(pmu))
2336 * Groups can be scheduled in as one unit only, so undo any
2337 * partial group before returning:
2338 * The events up to the failed event are scheduled out normally.
2340 for_each_sibling_event(event, group_event) {
2341 if (event == partial_group)
2344 event_sched_out(event, cpuctx, ctx);
2346 event_sched_out(group_event, cpuctx, ctx);
2348 pmu->cancel_txn(pmu);
2350 perf_mux_hrtimer_restart(cpuctx);
2356 * Work out whether we can put this event group on the CPU now.
2358 static int group_can_go_on(struct perf_event *event,
2359 struct perf_cpu_context *cpuctx,
2363 * Groups consisting entirely of software events can always go on.
2365 if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2368 * If an exclusive group is already on, no other hardware
2371 if (cpuctx->exclusive)
2374 * If this group is exclusive and there are already
2375 * events on the CPU, it can't go on.
2377 if (event->attr.exclusive && cpuctx->active_oncpu)
2380 * Otherwise, try to add it if all previous groups were able
2386 static void add_event_to_ctx(struct perf_event *event,
2387 struct perf_event_context *ctx)
2389 list_add_event(event, ctx);
2390 perf_group_attach(event);
2393 static void ctx_sched_out(struct perf_event_context *ctx,
2394 struct perf_cpu_context *cpuctx,
2395 enum event_type_t event_type);
2397 ctx_sched_in(struct perf_event_context *ctx,
2398 struct perf_cpu_context *cpuctx,
2399 enum event_type_t event_type,
2400 struct task_struct *task);
2402 static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2403 struct perf_event_context *ctx,
2404 enum event_type_t event_type)
2406 if (!cpuctx->task_ctx)
2409 if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2412 ctx_sched_out(ctx, cpuctx, event_type);
2415 static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2416 struct perf_event_context *ctx,
2417 struct task_struct *task)
2419 cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2421 ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2422 cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2424 ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2428 * We want to maintain the following priority of scheduling:
2429 * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2430 * - task pinned (EVENT_PINNED)
2431 * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2432 * - task flexible (EVENT_FLEXIBLE).
2434 * In order to avoid unscheduling and scheduling back in everything every
2435 * time an event is added, only do it for the groups of equal priority and
2438 * This can be called after a batch operation on task events, in which case
2439 * event_type is a bit mask of the types of events involved. For CPU events,
2440 * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2442 static void ctx_resched(struct perf_cpu_context *cpuctx,
2443 struct perf_event_context *task_ctx,
2444 enum event_type_t event_type)
2446 enum event_type_t ctx_event_type;
2447 bool cpu_event = !!(event_type & EVENT_CPU);
2450 * If pinned groups are involved, flexible groups also need to be
2453 if (event_type & EVENT_PINNED)
2454 event_type |= EVENT_FLEXIBLE;
2456 ctx_event_type = event_type & EVENT_ALL;
2458 perf_pmu_disable(cpuctx->ctx.pmu);
2460 task_ctx_sched_out(cpuctx, task_ctx, event_type);
2463 * Decide which cpu ctx groups to schedule out based on the types
2464 * of events that caused rescheduling:
2465 * - EVENT_CPU: schedule out corresponding groups;
2466 * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2467 * - otherwise, do nothing more.
2470 cpu_ctx_sched_out(cpuctx, ctx_event_type);
2471 else if (ctx_event_type & EVENT_PINNED)
2472 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2474 perf_event_sched_in(cpuctx, task_ctx, current);
2475 perf_pmu_enable(cpuctx->ctx.pmu);
2479 * Cross CPU call to install and enable a performance event
2481 * Very similar to remote_function() + event_function() but cannot assume that
2482 * things like ctx->is_active and cpuctx->task_ctx are set.
2484 static int __perf_install_in_context(void *info)
2486 struct perf_event *event = info;
2487 struct perf_event_context *ctx = event->ctx;
2488 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2489 struct perf_event_context *task_ctx = cpuctx->task_ctx;
2490 bool reprogram = true;
2493 raw_spin_lock(&cpuctx->ctx.lock);
2495 raw_spin_lock(&ctx->lock);
2498 reprogram = (ctx->task == current);
2501 * If the task is running, it must be running on this CPU,
2502 * otherwise we cannot reprogram things.
2504 * If its not running, we don't care, ctx->lock will
2505 * serialize against it becoming runnable.
2507 if (task_curr(ctx->task) && !reprogram) {
2512 WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2513 } else if (task_ctx) {
2514 raw_spin_lock(&task_ctx->lock);
2517 #ifdef CONFIG_CGROUP_PERF
2518 if (is_cgroup_event(event)) {
2520 * If the current cgroup doesn't match the event's
2521 * cgroup, we should not try to schedule it.
2523 struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2524 reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2525 event->cgrp->css.cgroup);
2530 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2531 add_event_to_ctx(event, ctx);
2532 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2534 add_event_to_ctx(event, ctx);
2538 perf_ctx_unlock(cpuctx, task_ctx);
2544 * Attach a performance event to a context.
2546 * Very similar to event_function_call, see comment there.
2549 perf_install_in_context(struct perf_event_context *ctx,
2550 struct perf_event *event,
2553 struct task_struct *task = READ_ONCE(ctx->task);
2555 lockdep_assert_held(&ctx->mutex);
2557 if (event->cpu != -1)
2561 * Ensures that if we can observe event->ctx, both the event and ctx
2562 * will be 'complete'. See perf_iterate_sb_cpu().
2564 smp_store_release(&event->ctx, ctx);
2567 cpu_function_call(cpu, __perf_install_in_context, event);
2572 * Should not happen, we validate the ctx is still alive before calling.
2574 if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2578 * Installing events is tricky because we cannot rely on ctx->is_active
2579 * to be set in case this is the nr_events 0 -> 1 transition.
2581 * Instead we use task_curr(), which tells us if the task is running.
2582 * However, since we use task_curr() outside of rq::lock, we can race
2583 * against the actual state. This means the result can be wrong.
2585 * If we get a false positive, we retry, this is harmless.
2587 * If we get a false negative, things are complicated. If we are after
2588 * perf_event_context_sched_in() ctx::lock will serialize us, and the
2589 * value must be correct. If we're before, it doesn't matter since
2590 * perf_event_context_sched_in() will program the counter.
2592 * However, this hinges on the remote context switch having observed
2593 * our task->perf_event_ctxp[] store, such that it will in fact take
2594 * ctx::lock in perf_event_context_sched_in().
2596 * We do this by task_function_call(), if the IPI fails to hit the task
2597 * we know any future context switch of task must see the
2598 * perf_event_ctpx[] store.
2602 * This smp_mb() orders the task->perf_event_ctxp[] store with the
2603 * task_cpu() load, such that if the IPI then does not find the task
2604 * running, a future context switch of that task must observe the
2609 if (!task_function_call(task, __perf_install_in_context, event))
2612 raw_spin_lock_irq(&ctx->lock);
2614 if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2616 * Cannot happen because we already checked above (which also
2617 * cannot happen), and we hold ctx->mutex, which serializes us
2618 * against perf_event_exit_task_context().
2620 raw_spin_unlock_irq(&ctx->lock);
2624 * If the task is not running, ctx->lock will avoid it becoming so,
2625 * thus we can safely install the event.
2627 if (task_curr(task)) {
2628 raw_spin_unlock_irq(&ctx->lock);
2631 add_event_to_ctx(event, ctx);
2632 raw_spin_unlock_irq(&ctx->lock);
2636 * Cross CPU call to enable a performance event
2638 static void __perf_event_enable(struct perf_event *event,
2639 struct perf_cpu_context *cpuctx,
2640 struct perf_event_context *ctx,
2643 struct perf_event *leader = event->group_leader;
2644 struct perf_event_context *task_ctx;
2646 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2647 event->state <= PERF_EVENT_STATE_ERROR)
2651 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2653 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2655 if (!ctx->is_active)
2658 if (!event_filter_match(event)) {
2659 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2664 * If the event is in a group and isn't the group leader,
2665 * then don't put it on unless the group is on.
2667 if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2668 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2672 task_ctx = cpuctx->task_ctx;
2674 WARN_ON_ONCE(task_ctx != ctx);
2676 ctx_resched(cpuctx, task_ctx, get_event_type(event));
2682 * If event->ctx is a cloned context, callers must make sure that
2683 * every task struct that event->ctx->task could possibly point to
2684 * remains valid. This condition is satisfied when called through
2685 * perf_event_for_each_child or perf_event_for_each as described
2686 * for perf_event_disable.
2688 static void _perf_event_enable(struct perf_event *event)
2690 struct perf_event_context *ctx = event->ctx;
2692 raw_spin_lock_irq(&ctx->lock);
2693 if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2694 event->state < PERF_EVENT_STATE_ERROR) {
2695 raw_spin_unlock_irq(&ctx->lock);
2700 * If the event is in error state, clear that first.
2702 * That way, if we see the event in error state below, we know that it
2703 * has gone back into error state, as distinct from the task having
2704 * been scheduled away before the cross-call arrived.
2706 if (event->state == PERF_EVENT_STATE_ERROR)
2707 event->state = PERF_EVENT_STATE_OFF;
2708 raw_spin_unlock_irq(&ctx->lock);
2710 event_function_call(event, __perf_event_enable, NULL);
2714 * See perf_event_disable();
2716 void perf_event_enable(struct perf_event *event)
2718 struct perf_event_context *ctx;
2720 ctx = perf_event_ctx_lock(event);
2721 _perf_event_enable(event);
2722 perf_event_ctx_unlock(event, ctx);
2724 EXPORT_SYMBOL_GPL(perf_event_enable);
2726 struct stop_event_data {
2727 struct perf_event *event;
2728 unsigned int restart;
2731 static int __perf_event_stop(void *info)
2733 struct stop_event_data *sd = info;
2734 struct perf_event *event = sd->event;
2736 /* if it's already INACTIVE, do nothing */
2737 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2740 /* matches smp_wmb() in event_sched_in() */
2744 * There is a window with interrupts enabled before we get here,
2745 * so we need to check again lest we try to stop another CPU's event.
2747 if (READ_ONCE(event->oncpu) != smp_processor_id())
2750 event->pmu->stop(event, PERF_EF_UPDATE);
2753 * May race with the actual stop (through perf_pmu_output_stop()),
2754 * but it is only used for events with AUX ring buffer, and such
2755 * events will refuse to restart because of rb::aux_mmap_count==0,
2756 * see comments in perf_aux_output_begin().
2758 * Since this is happening on an event-local CPU, no trace is lost
2762 event->pmu->start(event, 0);
2767 static int perf_event_stop(struct perf_event *event, int restart)
2769 struct stop_event_data sd = {
2776 if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
2779 /* matches smp_wmb() in event_sched_in() */
2783 * We only want to restart ACTIVE events, so if the event goes
2784 * inactive here (event->oncpu==-1), there's nothing more to do;
2785 * fall through with ret==-ENXIO.
2787 ret = cpu_function_call(READ_ONCE(event->oncpu),
2788 __perf_event_stop, &sd);
2789 } while (ret == -EAGAIN);
2795 * In order to contain the amount of racy and tricky in the address filter
2796 * configuration management, it is a two part process:
2798 * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
2799 * we update the addresses of corresponding vmas in
2800 * event::addr_filters_offs array and bump the event::addr_filters_gen;
2801 * (p2) when an event is scheduled in (pmu::add), it calls
2802 * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
2803 * if the generation has changed since the previous call.
2805 * If (p1) happens while the event is active, we restart it to force (p2).
2807 * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
2808 * pre-existing mappings, called once when new filters arrive via SET_FILTER
2810 * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
2811 * registered mapping, called for every new mmap(), with mm::mmap_sem down
2813 * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
2816 void perf_event_addr_filters_sync(struct perf_event *event)
2818 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
2820 if (!has_addr_filter(event))
2823 raw_spin_lock(&ifh->lock);
2824 if (event->addr_filters_gen != event->hw.addr_filters_gen) {
2825 event->pmu->addr_filters_sync(event);
2826 event->hw.addr_filters_gen = event->addr_filters_gen;
2828 raw_spin_unlock(&ifh->lock);
2830 EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
2832 static int _perf_event_refresh(struct perf_event *event, int refresh)
2835 * not supported on inherited events
2837 if (event->attr.inherit || !is_sampling_event(event))
2840 atomic_add(refresh, &event->event_limit);
2841 _perf_event_enable(event);
2847 * See perf_event_disable()
2849 int perf_event_refresh(struct perf_event *event, int refresh)
2851 struct perf_event_context *ctx;
2854 ctx = perf_event_ctx_lock(event);
2855 ret = _perf_event_refresh(event, refresh);
2856 perf_event_ctx_unlock(event, ctx);
2860 EXPORT_SYMBOL_GPL(perf_event_refresh);
2862 static int perf_event_modify_breakpoint(struct perf_event *bp,
2863 struct perf_event_attr *attr)
2867 _perf_event_disable(bp);
2869 err = modify_user_hw_breakpoint_check(bp, attr, true);
2871 if (!bp->attr.disabled)
2872 _perf_event_enable(bp);
2877 static int perf_event_modify_attr(struct perf_event *event,
2878 struct perf_event_attr *attr)
2880 if (event->attr.type != attr->type)
2883 switch (event->attr.type) {
2884 case PERF_TYPE_BREAKPOINT:
2885 return perf_event_modify_breakpoint(event, attr);
2887 /* Place holder for future additions. */
2892 static void ctx_sched_out(struct perf_event_context *ctx,
2893 struct perf_cpu_context *cpuctx,
2894 enum event_type_t event_type)
2896 struct perf_event *event, *tmp;
2897 int is_active = ctx->is_active;
2899 lockdep_assert_held(&ctx->lock);
2901 if (likely(!ctx->nr_events)) {
2903 * See __perf_remove_from_context().
2905 WARN_ON_ONCE(ctx->is_active);
2907 WARN_ON_ONCE(cpuctx->task_ctx);
2911 ctx->is_active &= ~event_type;
2912 if (!(ctx->is_active & EVENT_ALL))
2916 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2917 if (!ctx->is_active)
2918 cpuctx->task_ctx = NULL;
2922 * Always update time if it was set; not only when it changes.
2923 * Otherwise we can 'forget' to update time for any but the last
2924 * context we sched out. For example:
2926 * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
2927 * ctx_sched_out(.event_type = EVENT_PINNED)
2929 * would only update time for the pinned events.
2931 if (is_active & EVENT_TIME) {
2932 /* update (and stop) ctx time */
2933 update_context_time(ctx);
2934 update_cgrp_time_from_cpuctx(cpuctx);
2937 is_active ^= ctx->is_active; /* changed bits */
2939 if (!ctx->nr_active || !(is_active & EVENT_ALL))
2942 perf_pmu_disable(ctx->pmu);
2943 if (is_active & EVENT_PINNED) {
2944 list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
2945 group_sched_out(event, cpuctx, ctx);
2948 if (is_active & EVENT_FLEXIBLE) {
2949 list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
2950 group_sched_out(event, cpuctx, ctx);
2952 perf_pmu_enable(ctx->pmu);
2956 * Test whether two contexts are equivalent, i.e. whether they have both been
2957 * cloned from the same version of the same context.
2959 * Equivalence is measured using a generation number in the context that is
2960 * incremented on each modification to it; see unclone_ctx(), list_add_event()
2961 * and list_del_event().
2963 static int context_equiv(struct perf_event_context *ctx1,
2964 struct perf_event_context *ctx2)
2966 lockdep_assert_held(&ctx1->lock);
2967 lockdep_assert_held(&ctx2->lock);
2969 /* Pinning disables the swap optimization */
2970 if (ctx1->pin_count || ctx2->pin_count)
2973 /* If ctx1 is the parent of ctx2 */
2974 if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
2977 /* If ctx2 is the parent of ctx1 */
2978 if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
2982 * If ctx1 and ctx2 have the same parent; we flatten the parent
2983 * hierarchy, see perf_event_init_context().
2985 if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
2986 ctx1->parent_gen == ctx2->parent_gen)
2993 static void __perf_event_sync_stat(struct perf_event *event,
2994 struct perf_event *next_event)
2998 if (!event->attr.inherit_stat)
3002 * Update the event value, we cannot use perf_event_read()
3003 * because we're in the middle of a context switch and have IRQs
3004 * disabled, which upsets smp_call_function_single(), however
3005 * we know the event must be on the current CPU, therefore we
3006 * don't need to use it.
3008 if (event->state == PERF_EVENT_STATE_ACTIVE)
3009 event->pmu->read(event);
3011 perf_event_update_time(event);
3014 * In order to keep per-task stats reliable we need to flip the event
3015 * values when we flip the contexts.
3017 value = local64_read(&next_event->count);
3018 value = local64_xchg(&event->count, value);
3019 local64_set(&next_event->count, value);
3021 swap(event->total_time_enabled, next_event->total_time_enabled);
3022 swap(event->total_time_running, next_event->total_time_running);
3025 * Since we swizzled the values, update the user visible data too.
3027 perf_event_update_userpage(event);
3028 perf_event_update_userpage(next_event);
3031 static void perf_event_sync_stat(struct perf_event_context *ctx,
3032 struct perf_event_context *next_ctx)
3034 struct perf_event *event, *next_event;
3039 update_context_time(ctx);
3041 event = list_first_entry(&ctx->event_list,
3042 struct perf_event, event_entry);
3044 next_event = list_first_entry(&next_ctx->event_list,
3045 struct perf_event, event_entry);
3047 while (&event->event_entry != &ctx->event_list &&
3048 &next_event->event_entry != &next_ctx->event_list) {
3050 __perf_event_sync_stat(event, next_event);
3052 event = list_next_entry(event, event_entry);
3053 next_event = list_next_entry(next_event, event_entry);
3057 static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3058 struct task_struct *next)
3060 struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3061 struct perf_event_context *next_ctx;
3062 struct perf_event_context *parent, *next_parent;
3063 struct perf_cpu_context *cpuctx;
3069 cpuctx = __get_cpu_context(ctx);
3070 if (!cpuctx->task_ctx)
3074 next_ctx = next->perf_event_ctxp[ctxn];
3078 parent = rcu_dereference(ctx->parent_ctx);
3079 next_parent = rcu_dereference(next_ctx->parent_ctx);
3081 /* If neither context have a parent context; they cannot be clones. */
3082 if (!parent && !next_parent)
3085 if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3087 * Looks like the two contexts are clones, so we might be
3088 * able to optimize the context switch. We lock both
3089 * contexts and check that they are clones under the
3090 * lock (including re-checking that neither has been
3091 * uncloned in the meantime). It doesn't matter which
3092 * order we take the locks because no other cpu could
3093 * be trying to lock both of these tasks.
3095 raw_spin_lock(&ctx->lock);
3096 raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3097 if (context_equiv(ctx, next_ctx)) {
3098 WRITE_ONCE(ctx->task, next);
3099 WRITE_ONCE(next_ctx->task, task);
3101 swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3104 * RCU_INIT_POINTER here is safe because we've not
3105 * modified the ctx and the above modification of
3106 * ctx->task and ctx->task_ctx_data are immaterial
3107 * since those values are always verified under
3108 * ctx->lock which we're now holding.
3110 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3111 RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3115 perf_event_sync_stat(ctx, next_ctx);
3117 raw_spin_unlock(&next_ctx->lock);
3118 raw_spin_unlock(&ctx->lock);
3124 raw_spin_lock(&ctx->lock);
3125 task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3126 raw_spin_unlock(&ctx->lock);
3130 static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3132 void perf_sched_cb_dec(struct pmu *pmu)
3134 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3136 this_cpu_dec(perf_sched_cb_usages);
3138 if (!--cpuctx->sched_cb_usage)
3139 list_del(&cpuctx->sched_cb_entry);
3143 void perf_sched_cb_inc(struct pmu *pmu)
3145 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3147 if (!cpuctx->sched_cb_usage++)
3148 list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3150 this_cpu_inc(perf_sched_cb_usages);
3154 * This function provides the context switch callback to the lower code
3155 * layer. It is invoked ONLY when the context switch callback is enabled.
3157 * This callback is relevant even to per-cpu events; for example multi event
3158 * PEBS requires this to provide PID/TID information. This requires we flush
3159 * all queued PEBS records before we context switch to a new task.
3161 static void perf_pmu_sched_task(struct task_struct *prev,
3162 struct task_struct *next,
3165 struct perf_cpu_context *cpuctx;
3171 list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3172 pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3174 if (WARN_ON_ONCE(!pmu->sched_task))
3177 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3178 perf_pmu_disable(pmu);
3180 pmu->sched_task(cpuctx->task_ctx, sched_in);
3182 perf_pmu_enable(pmu);
3183 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3187 static void perf_event_switch(struct task_struct *task,
3188 struct task_struct *next_prev, bool sched_in);
3190 #define for_each_task_context_nr(ctxn) \
3191 for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3194 * Called from scheduler to remove the events of the current task,
3195 * with interrupts disabled.
3197 * We stop each event and update the event value in event->count.
3199 * This does not protect us against NMI, but disable()
3200 * sets the disabled bit in the control field of event _before_
3201 * accessing the event control register. If a NMI hits, then it will
3202 * not restart the event.
3204 void __perf_event_task_sched_out(struct task_struct *task,
3205 struct task_struct *next)
3209 if (__this_cpu_read(perf_sched_cb_usages))
3210 perf_pmu_sched_task(task, next, false);
3212 if (atomic_read(&nr_switch_events))
3213 perf_event_switch(task, next, false);
3215 for_each_task_context_nr(ctxn)
3216 perf_event_context_sched_out(task, ctxn, next);
3219 * if cgroup events exist on this CPU, then we need
3220 * to check if we have to switch out PMU state.
3221 * cgroup event are system-wide mode only
3223 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3224 perf_cgroup_sched_out(task, next);
3228 * Called with IRQs disabled
3230 static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3231 enum event_type_t event_type)
3233 ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3236 static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
3237 int (*func)(struct perf_event *, void *), void *data)
3239 struct perf_event **evt, *evt1, *evt2;
3242 evt1 = perf_event_groups_first(groups, -1);
3243 evt2 = perf_event_groups_first(groups, cpu);
3245 while (evt1 || evt2) {
3247 if (evt1->group_index < evt2->group_index)
3257 ret = func(*evt, data);
3261 *evt = perf_event_groups_next(*evt);
3267 struct sched_in_data {
3268 struct perf_event_context *ctx;
3269 struct perf_cpu_context *cpuctx;
3273 static int pinned_sched_in(struct perf_event *event, void *data)
3275 struct sched_in_data *sid = data;
3277 if (event->state <= PERF_EVENT_STATE_OFF)
3280 if (!event_filter_match(event))
3283 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3284 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3285 list_add_tail(&event->active_list, &sid->ctx->pinned_active);
3289 * If this pinned group hasn't been scheduled,
3290 * put it in error state.
3292 if (event->state == PERF_EVENT_STATE_INACTIVE)
3293 perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3298 static int flexible_sched_in(struct perf_event *event, void *data)
3300 struct sched_in_data *sid = data;
3302 if (event->state <= PERF_EVENT_STATE_OFF)
3305 if (!event_filter_match(event))
3308 if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
3309 if (!group_sched_in(event, sid->cpuctx, sid->ctx))
3310 list_add_tail(&event->active_list, &sid->ctx->flexible_active);
3312 sid->can_add_hw = 0;
3319 ctx_pinned_sched_in(struct perf_event_context *ctx,
3320 struct perf_cpu_context *cpuctx)
3322 struct sched_in_data sid = {
3328 visit_groups_merge(&ctx->pinned_groups,
3330 pinned_sched_in, &sid);
3334 ctx_flexible_sched_in(struct perf_event_context *ctx,
3335 struct perf_cpu_context *cpuctx)
3337 struct sched_in_data sid = {
3343 visit_groups_merge(&ctx->flexible_groups,
3345 flexible_sched_in, &sid);
3349 ctx_sched_in(struct perf_event_context *ctx,
3350 struct perf_cpu_context *cpuctx,
3351 enum event_type_t event_type,
3352 struct task_struct *task)
3354 int is_active = ctx->is_active;
3357 lockdep_assert_held(&ctx->lock);
3359 if (likely(!ctx->nr_events))
3362 ctx->is_active |= (event_type | EVENT_TIME);
3365 cpuctx->task_ctx = ctx;
3367 WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3370 is_active ^= ctx->is_active; /* changed bits */
3372 if (is_active & EVENT_TIME) {
3373 /* start ctx time */
3375 ctx->timestamp = now;
3376 perf_cgroup_set_timestamp(task, ctx);
3380 * First go through the list and put on any pinned groups
3381 * in order to give them the best chance of going on.
3383 if (is_active & EVENT_PINNED)
3384 ctx_pinned_sched_in(ctx, cpuctx);
3386 /* Then walk through the lower prio flexible groups */
3387 if (is_active & EVENT_FLEXIBLE)
3388 ctx_flexible_sched_in(ctx, cpuctx);
3391 static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3392 enum event_type_t event_type,
3393 struct task_struct *task)
3395 struct perf_event_context *ctx = &cpuctx->ctx;
3397 ctx_sched_in(ctx, cpuctx, event_type, task);
3400 static void perf_event_context_sched_in(struct perf_event_context *ctx,
3401 struct task_struct *task)
3403 struct perf_cpu_context *cpuctx;
3405 cpuctx = __get_cpu_context(ctx);
3406 if (cpuctx->task_ctx == ctx)
3409 perf_ctx_lock(cpuctx, ctx);
3411 * We must check ctx->nr_events while holding ctx->lock, such
3412 * that we serialize against perf_install_in_context().
3414 if (!ctx->nr_events)
3417 perf_pmu_disable(ctx->pmu);
3419 * We want to keep the following priority order:
3420 * cpu pinned (that don't need to move), task pinned,
3421 * cpu flexible, task flexible.
3423 * However, if task's ctx is not carrying any pinned
3424 * events, no need to flip the cpuctx's events around.
3426 if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3427 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3428 perf_event_sched_in(cpuctx, ctx, task);
3429 perf_pmu_enable(ctx->pmu);
3432 perf_ctx_unlock(cpuctx, ctx);
3436 * Called from scheduler to add the events of the current task
3437 * with interrupts disabled.
3439 * We restore the event value and then enable it.
3441 * This does not protect us against NMI, but enable()
3442 * sets the enabled bit in the control field of event _before_
3443 * accessing the event control register. If a NMI hits, then it will
3444 * keep the event running.
3446 void __perf_event_task_sched_in(struct task_struct *prev,
3447 struct task_struct *task)
3449 struct perf_event_context *ctx;
3453 * If cgroup events exist on this CPU, then we need to check if we have
3454 * to switch in PMU state; cgroup event are system-wide mode only.
3456 * Since cgroup events are CPU events, we must schedule these in before
3457 * we schedule in the task events.
3459 if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3460 perf_cgroup_sched_in(prev, task);
3462 for_each_task_context_nr(ctxn) {
3463 ctx = task->perf_event_ctxp[ctxn];
3467 perf_event_context_sched_in(ctx, task);
3470 if (atomic_read(&nr_switch_events))
3471 perf_event_switch(task, prev, true);
3473 if (__this_cpu_read(perf_sched_cb_usages))
3474 perf_pmu_sched_task(prev, task, true);
3477 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3479 u64 frequency = event->attr.sample_freq;
3480 u64 sec = NSEC_PER_SEC;
3481 u64 divisor, dividend;
3483 int count_fls, nsec_fls, frequency_fls, sec_fls;
3485 count_fls = fls64(count);
3486 nsec_fls = fls64(nsec);
3487 frequency_fls = fls64(frequency);
3491 * We got @count in @nsec, with a target of sample_freq HZ
3492 * the target period becomes:
3495 * period = -------------------
3496 * @nsec * sample_freq
3501 * Reduce accuracy by one bit such that @a and @b converge
3502 * to a similar magnitude.
3504 #define REDUCE_FLS(a, b) \
3506 if (a##_fls > b##_fls) { \
3516 * Reduce accuracy until either term fits in a u64, then proceed with
3517 * the other, so that finally we can do a u64/u64 division.
3519 while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3520 REDUCE_FLS(nsec, frequency);
3521 REDUCE_FLS(sec, count);
3524 if (count_fls + sec_fls > 64) {
3525 divisor = nsec * frequency;
3527 while (count_fls + sec_fls > 64) {
3528 REDUCE_FLS(count, sec);
3532 dividend = count * sec;
3534 dividend = count * sec;
3536 while (nsec_fls + frequency_fls > 64) {
3537 REDUCE_FLS(nsec, frequency);
3541 divisor = nsec * frequency;
3547 return div64_u64(dividend, divisor);
3550 static DEFINE_PER_CPU(int, perf_throttled_count);
3551 static DEFINE_PER_CPU(u64, perf_throttled_seq);
3553 static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3555 struct hw_perf_event *hwc = &event->hw;
3556 s64 period, sample_period;
3559 period = perf_calculate_period(event, nsec, count);
3561 delta = (s64)(period - hwc->sample_period);
3562 delta = (delta + 7) / 8; /* low pass filter */
3564 sample_period = hwc->sample_period + delta;
3569 hwc->sample_period = sample_period;
3571 if (local64_read(&hwc->period_left) > 8*sample_period) {
3573 event->pmu->stop(event, PERF_EF_UPDATE);
3575 local64_set(&hwc->period_left, 0);
3578 event->pmu->start(event, PERF_EF_RELOAD);
3583 * combine freq adjustment with unthrottling to avoid two passes over the
3584 * events. At the same time, make sure, having freq events does not change
3585 * the rate of unthrottling as that would introduce bias.
3587 static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3590 struct perf_event *event;
3591 struct hw_perf_event *hwc;
3592 u64 now, period = TICK_NSEC;
3596 * only need to iterate over all events iff:
3597 * - context have events in frequency mode (needs freq adjust)
3598 * - there are events to unthrottle on this cpu
3600 if (!(ctx->nr_freq || needs_unthr))
3603 raw_spin_lock(&ctx->lock);
3604 perf_pmu_disable(ctx->pmu);
3606 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
3607 if (event->state != PERF_EVENT_STATE_ACTIVE)
3610 if (!event_filter_match(event))
3613 perf_pmu_disable(event->pmu);
3617 if (hwc->interrupts == MAX_INTERRUPTS) {
3618 hwc->interrupts = 0;
3619 perf_log_throttle(event, 1);
3620 event->pmu->start(event, 0);
3623 if (!event->attr.freq || !event->attr.sample_freq)
3627 * stop the event and update event->count
3629 event->pmu->stop(event, PERF_EF_UPDATE);
3631 now = local64_read(&event->count);
3632 delta = now - hwc->freq_count_stamp;
3633 hwc->freq_count_stamp = now;
3637 * reload only if value has changed
3638 * we have stopped the event so tell that
3639 * to perf_adjust_period() to avoid stopping it
3643 perf_adjust_period(event, period, delta, false);
3645 event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
3647 perf_pmu_enable(event->pmu);
3650 perf_pmu_enable(ctx->pmu);
3651 raw_spin_unlock(&ctx->lock);
3655 * Move @event to the tail of the @ctx's elegible events.
3657 static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
3660 * Rotate the first entry last of non-pinned groups. Rotation might be
3661 * disabled by the inheritance code.
3663 if (ctx->rotate_disable)
3666 perf_event_groups_delete(&ctx->flexible_groups, event);
3667 perf_event_groups_insert(&ctx->flexible_groups, event);
3670 static inline struct perf_event *
3671 ctx_first_active(struct perf_event_context *ctx)
3673 return list_first_entry_or_null(&ctx->flexible_active,
3674 struct perf_event, active_list);
3677 static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
3679 struct perf_event *cpu_event = NULL, *task_event = NULL;
3680 bool cpu_rotate = false, task_rotate = false;
3681 struct perf_event_context *ctx = NULL;
3684 * Since we run this from IRQ context, nobody can install new
3685 * events, thus the event count values are stable.
3688 if (cpuctx->ctx.nr_events) {
3689 if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
3693 ctx = cpuctx->task_ctx;
3694 if (ctx && ctx->nr_events) {
3695 if (ctx->nr_events != ctx->nr_active)
3699 if (!(cpu_rotate || task_rotate))
3702 perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3703 perf_pmu_disable(cpuctx->ctx.pmu);
3706 task_event = ctx_first_active(ctx);
3708 cpu_event = ctx_first_active(&cpuctx->ctx);
3711 * As per the order given at ctx_resched() first 'pop' task flexible
3712 * and then, if needed CPU flexible.
3714 if (task_event || (ctx && cpu_event))
3715 ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
3717 cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3720 rotate_ctx(ctx, task_event);
3722 rotate_ctx(&cpuctx->ctx, cpu_event);
3724 perf_event_sched_in(cpuctx, ctx, current);
3726 perf_pmu_enable(cpuctx->ctx.pmu);
3727 perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3732 void perf_event_task_tick(void)
3734 struct list_head *head = this_cpu_ptr(&active_ctx_list);
3735 struct perf_event_context *ctx, *tmp;
3738 lockdep_assert_irqs_disabled();
3740 __this_cpu_inc(perf_throttled_seq);
3741 throttled = __this_cpu_xchg(perf_throttled_count, 0);
3742 tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
3744 list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
3745 perf_adjust_freq_unthr_context(ctx, throttled);
3748 static int event_enable_on_exec(struct perf_event *event,
3749 struct perf_event_context *ctx)
3751 if (!event->attr.enable_on_exec)
3754 event->attr.enable_on_exec = 0;
3755 if (event->state >= PERF_EVENT_STATE_INACTIVE)
3758 perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
3764 * Enable all of a task's events that have been marked enable-on-exec.
3765 * This expects task == current.
3767 static void perf_event_enable_on_exec(int ctxn)
3769 struct perf_event_context *ctx, *clone_ctx = NULL;
3770 enum event_type_t event_type = 0;
3771 struct perf_cpu_context *cpuctx;
3772 struct perf_event *event;
3773 unsigned long flags;
3776 local_irq_save(flags);
3777 ctx = current->perf_event_ctxp[ctxn];
3778 if (!ctx || !ctx->nr_events)
3781 cpuctx = __get_cpu_context(ctx);
3782 perf_ctx_lock(cpuctx, ctx);
3783 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
3784 list_for_each_entry(event, &ctx->event_list, event_entry) {
3785 enabled |= event_enable_on_exec(event, ctx);
3786 event_type |= get_event_type(event);
3790 * Unclone and reschedule this context if we enabled any event.
3793 clone_ctx = unclone_ctx(ctx);
3794 ctx_resched(cpuctx, ctx, event_type);
3796 ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
3798 perf_ctx_unlock(cpuctx, ctx);
3801 local_irq_restore(flags);
3807 struct perf_read_data {
3808 struct perf_event *event;
3813 static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
3815 u16 local_pkg, event_pkg;
3817 if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
3818 int local_cpu = smp_processor_id();
3820 event_pkg = topology_physical_package_id(event_cpu);
3821 local_pkg = topology_physical_package_id(local_cpu);
3823 if (event_pkg == local_pkg)
3831 * Cross CPU call to read the hardware event
3833 static void __perf_event_read(void *info)
3835 struct perf_read_data *data = info;
3836 struct perf_event *sub, *event = data->event;
3837 struct perf_event_context *ctx = event->ctx;
3838 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3839 struct pmu *pmu = event->pmu;
3842 * If this is a task context, we need to check whether it is
3843 * the current task context of this cpu. If not it has been
3844 * scheduled out before the smp call arrived. In that case
3845 * event->count would have been updated to a recent sample
3846 * when the event was scheduled out.
3848 if (ctx->task && cpuctx->task_ctx != ctx)
3851 raw_spin_lock(&ctx->lock);
3852 if (ctx->is_active & EVENT_TIME) {
3853 update_context_time(ctx);
3854 update_cgrp_time_from_event(event);
3857 perf_event_update_time(event);
3859 perf_event_update_sibling_time(event);
3861 if (event->state != PERF_EVENT_STATE_ACTIVE)
3870 pmu->start_txn(pmu, PERF_PMU_TXN_READ);
3874 for_each_sibling_event(sub, event) {
3875 if (sub->state == PERF_EVENT_STATE_ACTIVE) {
3877 * Use sibling's PMU rather than @event's since
3878 * sibling could be on different (eg: software) PMU.
3880 sub->pmu->read(sub);
3884 data->ret = pmu->commit_txn(pmu);
3887 raw_spin_unlock(&ctx->lock);
3890 static inline u64 perf_event_count(struct perf_event *event)
3892 return local64_read(&event->count) + atomic64_read(&event->child_count);
3896 * NMI-safe method to read a local event, that is an event that
3898 * - either for the current task, or for this CPU
3899 * - does not have inherit set, for inherited task events
3900 * will not be local and we cannot read them atomically
3901 * - must not have a pmu::count method
3903 int perf_event_read_local(struct perf_event *event, u64 *value,
3904 u64 *enabled, u64 *running)
3906 unsigned long flags;
3910 * Disabling interrupts avoids all counter scheduling (context
3911 * switches, timer based rotation and IPIs).
3913 local_irq_save(flags);
3916 * It must not be an event with inherit set, we cannot read
3917 * all child counters from atomic context.
3919 if (event->attr.inherit) {
3924 /* If this is a per-task event, it must be for current */
3925 if ((event->attach_state & PERF_ATTACH_TASK) &&
3926 event->hw.target != current) {
3931 /* If this is a per-CPU event, it must be for this CPU */
3932 if (!(event->attach_state & PERF_ATTACH_TASK) &&
3933 event->cpu != smp_processor_id()) {
3938 /* If this is a pinned event it must be running on this CPU */
3939 if (event->attr.pinned && event->oncpu != smp_processor_id()) {
3945 * If the event is currently on this CPU, its either a per-task event,
3946 * or local to this CPU. Furthermore it means its ACTIVE (otherwise
3949 if (event->oncpu == smp_processor_id())
3950 event->pmu->read(event);
3952 *value = local64_read(&event->count);
3953 if (enabled || running) {
3954 u64 now = event->shadow_ctx_time + perf_clock();
3955 u64 __enabled, __running;
3957 __perf_update_times(event, now, &__enabled, &__running);
3959 *enabled = __enabled;
3961 *running = __running;
3964 local_irq_restore(flags);
3969 static int perf_event_read(struct perf_event *event, bool group)
3971 enum perf_event_state state = READ_ONCE(event->state);
3972 int event_cpu, ret = 0;
3975 * If event is enabled and currently active on a CPU, update the
3976 * value in the event structure:
3979 if (state == PERF_EVENT_STATE_ACTIVE) {
3980 struct perf_read_data data;
3983 * Orders the ->state and ->oncpu loads such that if we see
3984 * ACTIVE we must also see the right ->oncpu.
3986 * Matches the smp_wmb() from event_sched_in().
3990 event_cpu = READ_ONCE(event->oncpu);
3991 if ((unsigned)event_cpu >= nr_cpu_ids)
3994 data = (struct perf_read_data){
4001 event_cpu = __perf_event_read_cpu(event, event_cpu);
4004 * Purposely ignore the smp_call_function_single() return
4007 * If event_cpu isn't a valid CPU it means the event got
4008 * scheduled out and that will have updated the event count.
4010 * Therefore, either way, we'll have an up-to-date event count
4013 (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4017 } else if (state == PERF_EVENT_STATE_INACTIVE) {
4018 struct perf_event_context *ctx = event->ctx;
4019 unsigned long flags;
4021 raw_spin_lock_irqsave(&ctx->lock, flags);
4022 state = event->state;
4023 if (state != PERF_EVENT_STATE_INACTIVE) {
4024 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4029 * May read while context is not active (e.g., thread is
4030 * blocked), in that case we cannot update context time
4032 if (ctx->is_active & EVENT_TIME) {
4033 update_context_time(ctx);
4034 update_cgrp_time_from_event(event);
4037 perf_event_update_time(event);
4039 perf_event_update_sibling_time(event);
4040 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4047 * Initialize the perf_event context in a task_struct:
4049 static void __perf_event_init_context(struct perf_event_context *ctx)
4051 raw_spin_lock_init(&ctx->lock);
4052 mutex_init(&ctx->mutex);
4053 INIT_LIST_HEAD(&ctx->active_ctx_list);
4054 perf_event_groups_init(&ctx->pinned_groups);
4055 perf_event_groups_init(&ctx->flexible_groups);
4056 INIT_LIST_HEAD(&ctx->event_list);
4057 INIT_LIST_HEAD(&ctx->pinned_active);
4058 INIT_LIST_HEAD(&ctx->flexible_active);
4059 atomic_set(&ctx->refcount, 1);
4062 static struct perf_event_context *
4063 alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4065 struct perf_event_context *ctx;
4067 ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4071 __perf_event_init_context(ctx);
4074 get_task_struct(task);
4081 static struct task_struct *
4082 find_lively_task_by_vpid(pid_t vpid)
4084 struct task_struct *task;
4090 task = find_task_by_vpid(vpid);
4092 get_task_struct(task);
4096 return ERR_PTR(-ESRCH);
4102 * Returns a matching context with refcount and pincount.
4104 static struct perf_event_context *
4105 find_get_context(struct pmu *pmu, struct task_struct *task,
4106 struct perf_event *event)
4108 struct perf_event_context *ctx, *clone_ctx = NULL;
4109 struct perf_cpu_context *cpuctx;
4110 void *task_ctx_data = NULL;
4111 unsigned long flags;
4113 int cpu = event->cpu;
4116 /* Must be root to operate on a CPU event: */
4117 if (perf_paranoid_cpu() && !capable(CAP_SYS_ADMIN))
4118 return ERR_PTR(-EACCES);
4120 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4129 ctxn = pmu->task_ctx_nr;
4133 if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4134 task_ctx_data = kzalloc(pmu->task_ctx_size, GFP_KERNEL);
4135 if (!task_ctx_data) {
4142 ctx = perf_lock_task_context(task, ctxn, &flags);
4144 clone_ctx = unclone_ctx(ctx);
4147 if (task_ctx_data && !ctx->task_ctx_data) {
4148 ctx->task_ctx_data = task_ctx_data;
4149 task_ctx_data = NULL;
4151 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4156 ctx = alloc_perf_context(pmu, task);
4161 if (task_ctx_data) {
4162 ctx->task_ctx_data = task_ctx_data;
4163 task_ctx_data = NULL;
4167 mutex_lock(&task->perf_event_mutex);
4169 * If it has already passed perf_event_exit_task().
4170 * we must see PF_EXITING, it takes this mutex too.
4172 if (task->flags & PF_EXITING)
4174 else if (task->perf_event_ctxp[ctxn])
4179 rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4181 mutex_unlock(&task->perf_event_mutex);
4183 if (unlikely(err)) {
4192 kfree(task_ctx_data);
4196 kfree(task_ctx_data);
4197 return ERR_PTR(err);
4200 static void perf_event_free_filter(struct perf_event *event);
4201 static void perf_event_free_bpf_prog(struct perf_event *event);
4203 static void free_event_rcu(struct rcu_head *head)
4205 struct perf_event *event;
4207 event = container_of(head, struct perf_event, rcu_head);
4209 put_pid_ns(event->ns);
4210 perf_event_free_filter(event);
4214 static void ring_buffer_attach(struct perf_event *event,
4215 struct ring_buffer *rb);
4217 static void detach_sb_event(struct perf_event *event)
4219 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4221 raw_spin_lock(&pel->lock);
4222 list_del_rcu(&event->sb_list);
4223 raw_spin_unlock(&pel->lock);
4226 static bool is_sb_event(struct perf_event *event)
4228 struct perf_event_attr *attr = &event->attr;
4233 if (event->attach_state & PERF_ATTACH_TASK)
4236 if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4237 attr->comm || attr->comm_exec ||
4239 attr->context_switch)
4244 static void unaccount_pmu_sb_event(struct perf_event *event)
4246 if (is_sb_event(event))
4247 detach_sb_event(event);
4250 static void unaccount_event_cpu(struct perf_event *event, int cpu)
4255 if (is_cgroup_event(event))
4256 atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4259 #ifdef CONFIG_NO_HZ_FULL
4260 static DEFINE_SPINLOCK(nr_freq_lock);
4263 static void unaccount_freq_event_nohz(void)
4265 #ifdef CONFIG_NO_HZ_FULL
4266 spin_lock(&nr_freq_lock);
4267 if (atomic_dec_and_test(&nr_freq_events))
4268 tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4269 spin_unlock(&nr_freq_lock);
4273 static void unaccount_freq_event(void)
4275 if (tick_nohz_full_enabled())
4276 unaccount_freq_event_nohz();
4278 atomic_dec(&nr_freq_events);
4281 static void unaccount_event(struct perf_event *event)
4288 if (event->attach_state & PERF_ATTACH_TASK)
4290 if (event->attr.mmap || event->attr.mmap_data)
4291 atomic_dec(&nr_mmap_events);
4292 if (event->attr.comm)
4293 atomic_dec(&nr_comm_events);
4294 if (event->attr.namespaces)
4295 atomic_dec(&nr_namespaces_events);
4296 if (event->attr.task)
4297 atomic_dec(&nr_task_events);
4298 if (event->attr.freq)
4299 unaccount_freq_event();
4300 if (event->attr.context_switch) {
4302 atomic_dec(&nr_switch_events);
4304 if (is_cgroup_event(event))
4306 if (has_branch_stack(event))
4310 if (!atomic_add_unless(&perf_sched_count, -1, 1))
4311 schedule_delayed_work(&perf_sched_work, HZ);
4314 unaccount_event_cpu(event, event->cpu);
4316 unaccount_pmu_sb_event(event);
4319 static void perf_sched_delayed(struct work_struct *work)
4321 mutex_lock(&perf_sched_mutex);
4322 if (atomic_dec_and_test(&perf_sched_count))
4323 static_branch_disable(&perf_sched_events);
4324 mutex_unlock(&perf_sched_mutex);
4328 * The following implement mutual exclusion of events on "exclusive" pmus
4329 * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4330 * at a time, so we disallow creating events that might conflict, namely:
4332 * 1) cpu-wide events in the presence of per-task events,
4333 * 2) per-task events in the presence of cpu-wide events,
4334 * 3) two matching events on the same context.
4336 * The former two cases are handled in the allocation path (perf_event_alloc(),
4337 * _free_event()), the latter -- before the first perf_install_in_context().
4339 static int exclusive_event_init(struct perf_event *event)
4341 struct pmu *pmu = event->pmu;
4343 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4347 * Prevent co-existence of per-task and cpu-wide events on the
4348 * same exclusive pmu.
4350 * Negative pmu::exclusive_cnt means there are cpu-wide
4351 * events on this "exclusive" pmu, positive means there are
4354 * Since this is called in perf_event_alloc() path, event::ctx
4355 * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4356 * to mean "per-task event", because unlike other attach states it
4357 * never gets cleared.
4359 if (event->attach_state & PERF_ATTACH_TASK) {
4360 if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4363 if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4370 static void exclusive_event_destroy(struct perf_event *event)
4372 struct pmu *pmu = event->pmu;
4374 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4377 /* see comment in exclusive_event_init() */
4378 if (event->attach_state & PERF_ATTACH_TASK)
4379 atomic_dec(&pmu->exclusive_cnt);
4381 atomic_inc(&pmu->exclusive_cnt);
4384 static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4386 if ((e1->pmu == e2->pmu) &&
4387 (e1->cpu == e2->cpu ||
4394 /* Called under the same ctx::mutex as perf_install_in_context() */
4395 static bool exclusive_event_installable(struct perf_event *event,
4396 struct perf_event_context *ctx)
4398 struct perf_event *iter_event;
4399 struct pmu *pmu = event->pmu;
4401 if (!(pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE))
4404 list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4405 if (exclusive_event_match(iter_event, event))
4412 static void perf_addr_filters_splice(struct perf_event *event,
4413 struct list_head *head);
4415 static void _free_event(struct perf_event *event)
4417 irq_work_sync(&event->pending);
4419 unaccount_event(event);
4423 * Can happen when we close an event with re-directed output.
4425 * Since we have a 0 refcount, perf_mmap_close() will skip
4426 * over us; possibly making our ring_buffer_put() the last.
4428 mutex_lock(&event->mmap_mutex);
4429 ring_buffer_attach(event, NULL);
4430 mutex_unlock(&event->mmap_mutex);
4433 if (is_cgroup_event(event))
4434 perf_detach_cgroup(event);
4436 if (!event->parent) {
4437 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4438 put_callchain_buffers();
4441 perf_event_free_bpf_prog(event);
4442 perf_addr_filters_splice(event, NULL);
4443 kfree(event->addr_filters_offs);
4446 event->destroy(event);
4449 put_ctx(event->ctx);
4451 if (event->hw.target)
4452 put_task_struct(event->hw.target);
4454 exclusive_event_destroy(event);
4455 module_put(event->pmu->module);
4457 call_rcu(&event->rcu_head, free_event_rcu);
4461 * Used to free events which have a known refcount of 1, such as in error paths
4462 * where the event isn't exposed yet and inherited events.
4464 static void free_event(struct perf_event *event)
4466 if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4467 "unexpected event refcount: %ld; ptr=%p\n",
4468 atomic_long_read(&event->refcount), event)) {
4469 /* leak to avoid use-after-free */
4477 * Remove user event from the owner task.
4479 static void perf_remove_from_owner(struct perf_event *event)
4481 struct task_struct *owner;
4485 * Matches the smp_store_release() in perf_event_exit_task(). If we
4486 * observe !owner it means the list deletion is complete and we can
4487 * indeed free this event, otherwise we need to serialize on
4488 * owner->perf_event_mutex.
4490 owner = READ_ONCE(event->owner);
4493 * Since delayed_put_task_struct() also drops the last
4494 * task reference we can safely take a new reference
4495 * while holding the rcu_read_lock().
4497 get_task_struct(owner);
4503 * If we're here through perf_event_exit_task() we're already
4504 * holding ctx->mutex which would be an inversion wrt. the
4505 * normal lock order.
4507 * However we can safely take this lock because its the child
4510 mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4513 * We have to re-check the event->owner field, if it is cleared
4514 * we raced with perf_event_exit_task(), acquiring the mutex
4515 * ensured they're done, and we can proceed with freeing the
4519 list_del_init(&event->owner_entry);
4520 smp_store_release(&event->owner, NULL);
4522 mutex_unlock(&owner->perf_event_mutex);
4523 put_task_struct(owner);
4527 static void put_event(struct perf_event *event)
4529 if (!atomic_long_dec_and_test(&event->refcount))
4536 * Kill an event dead; while event:refcount will preserve the event
4537 * object, it will not preserve its functionality. Once the last 'user'
4538 * gives up the object, we'll destroy the thing.
4540 int perf_event_release_kernel(struct perf_event *event)
4542 struct perf_event_context *ctx = event->ctx;
4543 struct perf_event *child, *tmp;
4544 LIST_HEAD(free_list);
4547 * If we got here through err_file: fput(event_file); we will not have
4548 * attached to a context yet.
4551 WARN_ON_ONCE(event->attach_state &
4552 (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4556 if (!is_kernel_event(event))
4557 perf_remove_from_owner(event);
4559 ctx = perf_event_ctx_lock(event);
4560 WARN_ON_ONCE(ctx->parent_ctx);
4561 perf_remove_from_context(event, DETACH_GROUP);
4563 raw_spin_lock_irq(&ctx->lock);
4565 * Mark this event as STATE_DEAD, there is no external reference to it
4568 * Anybody acquiring event->child_mutex after the below loop _must_
4569 * also see this, most importantly inherit_event() which will avoid
4570 * placing more children on the list.
4572 * Thus this guarantees that we will in fact observe and kill _ALL_
4575 event->state = PERF_EVENT_STATE_DEAD;
4576 raw_spin_unlock_irq(&ctx->lock);
4578 perf_event_ctx_unlock(event, ctx);
4581 mutex_lock(&event->child_mutex);
4582 list_for_each_entry(child, &event->child_list, child_list) {
4585 * Cannot change, child events are not migrated, see the
4586 * comment with perf_event_ctx_lock_nested().
4588 ctx = READ_ONCE(child->ctx);
4590 * Since child_mutex nests inside ctx::mutex, we must jump
4591 * through hoops. We start by grabbing a reference on the ctx.
4593 * Since the event cannot get freed while we hold the
4594 * child_mutex, the context must also exist and have a !0
4600 * Now that we have a ctx ref, we can drop child_mutex, and
4601 * acquire ctx::mutex without fear of it going away. Then we
4602 * can re-acquire child_mutex.
4604 mutex_unlock(&event->child_mutex);
4605 mutex_lock(&ctx->mutex);
4606 mutex_lock(&event->child_mutex);
4609 * Now that we hold ctx::mutex and child_mutex, revalidate our
4610 * state, if child is still the first entry, it didn't get freed
4611 * and we can continue doing so.
4613 tmp = list_first_entry_or_null(&event->child_list,
4614 struct perf_event, child_list);
4616 perf_remove_from_context(child, DETACH_GROUP);
4617 list_move(&child->child_list, &free_list);
4619 * This matches the refcount bump in inherit_event();
4620 * this can't be the last reference.
4625 mutex_unlock(&event->child_mutex);
4626 mutex_unlock(&ctx->mutex);
4630 mutex_unlock(&event->child_mutex);
4632 list_for_each_entry_safe(child, tmp, &free_list, child_list) {
4633 list_del(&child->child_list);
4638 put_event(event); /* Must be the 'last' reference */
4641 EXPORT_SYMBOL_GPL(perf_event_release_kernel);
4644 * Called when the last reference to the file is gone.
4646 static int perf_release(struct inode *inode, struct file *file)
4648 perf_event_release_kernel(file->private_data);
4652 static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4654 struct perf_event *child;
4660 mutex_lock(&event->child_mutex);
4662 (void)perf_event_read(event, false);
4663 total += perf_event_count(event);
4665 *enabled += event->total_time_enabled +
4666 atomic64_read(&event->child_total_time_enabled);
4667 *running += event->total_time_running +
4668 atomic64_read(&event->child_total_time_running);
4670 list_for_each_entry(child, &event->child_list, child_list) {
4671 (void)perf_event_read(child, false);
4672 total += perf_event_count(child);
4673 *enabled += child->total_time_enabled;
4674 *running += child->total_time_running;
4676 mutex_unlock(&event->child_mutex);
4681 u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
4683 struct perf_event_context *ctx;
4686 ctx = perf_event_ctx_lock(event);
4687 count = __perf_event_read_value(event, enabled, running);
4688 perf_event_ctx_unlock(event, ctx);
4692 EXPORT_SYMBOL_GPL(perf_event_read_value);
4694 static int __perf_read_group_add(struct perf_event *leader,
4695 u64 read_format, u64 *values)
4697 struct perf_event_context *ctx = leader->ctx;
4698 struct perf_event *sub;
4699 unsigned long flags;
4700 int n = 1; /* skip @nr */
4703 ret = perf_event_read(leader, true);
4707 raw_spin_lock_irqsave(&ctx->lock, flags);
4710 * Since we co-schedule groups, {enabled,running} times of siblings
4711 * will be identical to those of the leader, so we only publish one
4714 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
4715 values[n++] += leader->total_time_enabled +
4716 atomic64_read(&leader->child_total_time_enabled);
4719 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
4720 values[n++] += leader->total_time_running +
4721 atomic64_read(&leader->child_total_time_running);
4725 * Write {count,id} tuples for every sibling.
4727 values[n++] += perf_event_count(leader);
4728 if (read_format & PERF_FORMAT_ID)
4729 values[n++] = primary_event_id(leader);
4731 for_each_sibling_event(sub, leader) {
4732 values[n++] += perf_event_count(sub);
4733 if (read_format & PERF_FORMAT_ID)
4734 values[n++] = primary_event_id(sub);
4737 raw_spin_unlock_irqrestore(&ctx->lock, flags);
4741 static int perf_read_group(struct perf_event *event,
4742 u64 read_format, char __user *buf)
4744 struct perf_event *leader = event->group_leader, *child;
4745 struct perf_event_context *ctx = leader->ctx;
4749 lockdep_assert_held(&ctx->mutex);
4751 values = kzalloc(event->read_size, GFP_KERNEL);
4755 values[0] = 1 + leader->nr_siblings;
4758 * By locking the child_mutex of the leader we effectively
4759 * lock the child list of all siblings.. XXX explain how.
4761 mutex_lock(&leader->child_mutex);
4763 ret = __perf_read_group_add(leader, read_format, values);
4767 list_for_each_entry(child, &leader->child_list, child_list) {
4768 ret = __perf_read_group_add(child, read_format, values);
4773 mutex_unlock(&leader->child_mutex);
4775 ret = event->read_size;
4776 if (copy_to_user(buf, values, event->read_size))
4781 mutex_unlock(&leader->child_mutex);
4787 static int perf_read_one(struct perf_event *event,
4788 u64 read_format, char __user *buf)
4790 u64 enabled, running;
4794 values[n++] = __perf_event_read_value(event, &enabled, &running);
4795 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
4796 values[n++] = enabled;
4797 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
4798 values[n++] = running;
4799 if (read_format & PERF_FORMAT_ID)
4800 values[n++] = primary_event_id(event);
4802 if (copy_to_user(buf, values, n * sizeof(u64)))
4805 return n * sizeof(u64);
4808 static bool is_event_hup(struct perf_event *event)
4812 if (event->state > PERF_EVENT_STATE_EXIT)
4815 mutex_lock(&event->child_mutex);
4816 no_children = list_empty(&event->child_list);
4817 mutex_unlock(&event->child_mutex);
4822 * Read the performance event - simple non blocking version for now
4825 __perf_read(struct perf_event *event, char __user *buf, size_t count)
4827 u64 read_format = event->attr.read_format;
4831 * Return end-of-file for a read on an event that is in
4832 * error state (i.e. because it was pinned but it couldn't be
4833 * scheduled on to the CPU at some point).
4835 if (event->state == PERF_EVENT_STATE_ERROR)
4838 if (count < event->read_size)
4841 WARN_ON_ONCE(event->ctx->parent_ctx);
4842 if (read_format & PERF_FORMAT_GROUP)
4843 ret = perf_read_group(event, read_format, buf);
4845 ret = perf_read_one(event, read_format, buf);
4851 perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
4853 struct perf_event *event = file->private_data;
4854 struct perf_event_context *ctx;
4857 ctx = perf_event_ctx_lock(event);
4858 ret = __perf_read(event, buf, count);
4859 perf_event_ctx_unlock(event, ctx);
4864 static __poll_t perf_poll(struct file *file, poll_table *wait)
4866 struct perf_event *event = file->private_data;
4867 struct ring_buffer *rb;
4868 __poll_t events = EPOLLHUP;
4870 poll_wait(file, &event->waitq, wait);
4872 if (is_event_hup(event))
4876 * Pin the event->rb by taking event->mmap_mutex; otherwise
4877 * perf_event_set_output() can swizzle our rb and make us miss wakeups.
4879 mutex_lock(&event->mmap_mutex);
4882 events = atomic_xchg(&rb->poll, 0);
4883 mutex_unlock(&event->mmap_mutex);
4887 static void _perf_event_reset(struct perf_event *event)
4889 (void)perf_event_read(event, false);
4890 local64_set(&event->count, 0);
4891 perf_event_update_userpage(event);
4895 * Holding the top-level event's child_mutex means that any
4896 * descendant process that has inherited this event will block
4897 * in perf_event_exit_event() if it goes to exit, thus satisfying the
4898 * task existence requirements of perf_event_enable/disable.
4900 static void perf_event_for_each_child(struct perf_event *event,
4901 void (*func)(struct perf_event *))
4903 struct perf_event *child;
4905 WARN_ON_ONCE(event->ctx->parent_ctx);
4907 mutex_lock(&event->child_mutex);
4909 list_for_each_entry(child, &event->child_list, child_list)
4911 mutex_unlock(&event->child_mutex);
4914 static void perf_event_for_each(struct perf_event *event,
4915 void (*func)(struct perf_event *))
4917 struct perf_event_context *ctx = event->ctx;
4918 struct perf_event *sibling;
4920 lockdep_assert_held(&ctx->mutex);
4922 event = event->group_leader;
4924 perf_event_for_each_child(event, func);
4925 for_each_sibling_event(sibling, event)
4926 perf_event_for_each_child(sibling, func);
4929 static void __perf_event_period(struct perf_event *event,
4930 struct perf_cpu_context *cpuctx,
4931 struct perf_event_context *ctx,
4934 u64 value = *((u64 *)info);
4937 if (event->attr.freq) {
4938 event->attr.sample_freq = value;
4940 event->attr.sample_period = value;
4941 event->hw.sample_period = value;
4944 active = (event->state == PERF_EVENT_STATE_ACTIVE);
4946 perf_pmu_disable(ctx->pmu);
4948 * We could be throttled; unthrottle now to avoid the tick
4949 * trying to unthrottle while we already re-started the event.
4951 if (event->hw.interrupts == MAX_INTERRUPTS) {
4952 event->hw.interrupts = 0;
4953 perf_log_throttle(event, 1);
4955 event->pmu->stop(event, PERF_EF_UPDATE);
4958 local64_set(&event->hw.period_left, 0);
4961 event->pmu->start(event, PERF_EF_RELOAD);
4962 perf_pmu_enable(ctx->pmu);
4966 static int perf_event_check_period(struct perf_event *event, u64 value)
4968 return event->pmu->check_period(event, value);
4971 static int perf_event_period(struct perf_event *event, u64 __user *arg)
4975 if (!is_sampling_event(event))
4978 if (copy_from_user(&value, arg, sizeof(value)))
4984 if (event->attr.freq && value > sysctl_perf_event_sample_rate)
4987 if (perf_event_check_period(event, value))
4990 event_function_call(event, __perf_event_period, &value);
4995 static const struct file_operations perf_fops;
4997 static inline int perf_fget_light(int fd, struct fd *p)
4999 struct fd f = fdget(fd);
5003 if (f.file->f_op != &perf_fops) {
5011 static int perf_event_set_output(struct perf_event *event,
5012 struct perf_event *output_event);
5013 static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5014 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5015 static int perf_copy_attr(struct perf_event_attr __user *uattr,
5016 struct perf_event_attr *attr);
5018 static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5020 void (*func)(struct perf_event *);
5024 case PERF_EVENT_IOC_ENABLE:
5025 func = _perf_event_enable;
5027 case PERF_EVENT_IOC_DISABLE:
5028 func = _perf_event_disable;
5030 case PERF_EVENT_IOC_RESET:
5031 func = _perf_event_reset;
5034 case PERF_EVENT_IOC_REFRESH:
5035 return _perf_event_refresh(event, arg);
5037 case PERF_EVENT_IOC_PERIOD:
5038 return perf_event_period(event, (u64 __user *)arg);
5040 case PERF_EVENT_IOC_ID:
5042 u64 id = primary_event_id(event);
5044 if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5049 case PERF_EVENT_IOC_SET_OUTPUT:
5053 struct perf_event *output_event;
5055 ret = perf_fget_light(arg, &output);
5058 output_event = output.file->private_data;
5059 ret = perf_event_set_output(event, output_event);
5062 ret = perf_event_set_output(event, NULL);
5067 case PERF_EVENT_IOC_SET_FILTER:
5068 return perf_event_set_filter(event, (void __user *)arg);
5070 case PERF_EVENT_IOC_SET_BPF:
5071 return perf_event_set_bpf_prog(event, arg);
5073 case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5074 struct ring_buffer *rb;
5077 rb = rcu_dereference(event->rb);
5078 if (!rb || !rb->nr_pages) {
5082 rb_toggle_paused(rb, !!arg);
5087 case PERF_EVENT_IOC_QUERY_BPF:
5088 return perf_event_query_prog_array(event, (void __user *)arg);
5090 case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5091 struct perf_event_attr new_attr;
5092 int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5098 return perf_event_modify_attr(event, &new_attr);
5104 if (flags & PERF_IOC_FLAG_GROUP)
5105 perf_event_for_each(event, func);
5107 perf_event_for_each_child(event, func);
5112 static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5114 struct perf_event *event = file->private_data;
5115 struct perf_event_context *ctx;
5118 ctx = perf_event_ctx_lock(event);
5119 ret = _perf_ioctl(event, cmd, arg);
5120 perf_event_ctx_unlock(event, ctx);
5125 #ifdef CONFIG_COMPAT
5126 static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5129 switch (_IOC_NR(cmd)) {
5130 case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5131 case _IOC_NR(PERF_EVENT_IOC_ID):
5132 case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5133 case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5134 /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5135 if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5136 cmd &= ~IOCSIZE_MASK;
5137 cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5141 return perf_ioctl(file, cmd, arg);
5144 # define perf_compat_ioctl NULL
5147 int perf_event_task_enable(void)
5149 struct perf_event_context *ctx;
5150 struct perf_event *event;
5152 mutex_lock(¤t->perf_event_mutex);
5153 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5154 ctx = perf_event_ctx_lock(event);
5155 perf_event_for_each_child(event, _perf_event_enable);
5156 perf_event_ctx_unlock(event, ctx);
5158 mutex_unlock(¤t->perf_event_mutex);
5163 int perf_event_task_disable(void)
5165 struct perf_event_context *ctx;
5166 struct perf_event *event;
5168 mutex_lock(¤t->perf_event_mutex);
5169 list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5170 ctx = perf_event_ctx_lock(event);
5171 perf_event_for_each_child(event, _perf_event_disable);
5172 perf_event_ctx_unlock(event, ctx);
5174 mutex_unlock(¤t->perf_event_mutex);
5179 static int perf_event_index(struct perf_event *event)
5181 if (event->hw.state & PERF_HES_STOPPED)
5184 if (event->state != PERF_EVENT_STATE_ACTIVE)
5187 return event->pmu->event_idx(event);
5190 static void calc_timer_values(struct perf_event *event,
5197 *now = perf_clock();
5198 ctx_time = event->shadow_ctx_time + *now;
5199 __perf_update_times(event, ctx_time, enabled, running);
5202 static void perf_event_init_userpage(struct perf_event *event)
5204 struct perf_event_mmap_page *userpg;
5205 struct ring_buffer *rb;
5208 rb = rcu_dereference(event->rb);
5212 userpg = rb->user_page;
5214 /* Allow new userspace to detect that bit 0 is deprecated */
5215 userpg->cap_bit0_is_deprecated = 1;
5216 userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5217 userpg->data_offset = PAGE_SIZE;
5218 userpg->data_size = perf_data_size(rb);
5224 void __weak arch_perf_update_userpage(
5225 struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5230 * Callers need to ensure there can be no nesting of this function, otherwise
5231 * the seqlock logic goes bad. We can not serialize this because the arch
5232 * code calls this from NMI context.
5234 void perf_event_update_userpage(struct perf_event *event)
5236 struct perf_event_mmap_page *userpg;
5237 struct ring_buffer *rb;
5238 u64 enabled, running, now;
5241 rb = rcu_dereference(event->rb);
5246 * compute total_time_enabled, total_time_running
5247 * based on snapshot values taken when the event
5248 * was last scheduled in.
5250 * we cannot simply called update_context_time()
5251 * because of locking issue as we can be called in
5254 calc_timer_values(event, &now, &enabled, &running);
5256 userpg = rb->user_page;
5258 * Disable preemption to guarantee consistent time stamps are stored to
5264 userpg->index = perf_event_index(event);
5265 userpg->offset = perf_event_count(event);
5267 userpg->offset -= local64_read(&event->hw.prev_count);
5269 userpg->time_enabled = enabled +
5270 atomic64_read(&event->child_total_time_enabled);
5272 userpg->time_running = running +
5273 atomic64_read(&event->child_total_time_running);
5275 arch_perf_update_userpage(event, userpg, now);
5283 EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5285 static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5287 struct perf_event *event = vmf->vma->vm_file->private_data;
5288 struct ring_buffer *rb;
5289 vm_fault_t ret = VM_FAULT_SIGBUS;
5291 if (vmf->flags & FAULT_FLAG_MKWRITE) {
5292 if (vmf->pgoff == 0)
5298 rb = rcu_dereference(event->rb);
5302 if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5305 vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5309 get_page(vmf->page);
5310 vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5311 vmf->page->index = vmf->pgoff;
5320 static void ring_buffer_attach(struct perf_event *event,
5321 struct ring_buffer *rb)
5323 struct ring_buffer *old_rb = NULL;
5324 unsigned long flags;
5328 * Should be impossible, we set this when removing
5329 * event->rb_entry and wait/clear when adding event->rb_entry.
5331 WARN_ON_ONCE(event->rcu_pending);
5334 spin_lock_irqsave(&old_rb->event_lock, flags);
5335 list_del_rcu(&event->rb_entry);
5336 spin_unlock_irqrestore(&old_rb->event_lock, flags);
5338 event->rcu_batches = get_state_synchronize_rcu();
5339 event->rcu_pending = 1;
5343 if (event->rcu_pending) {
5344 cond_synchronize_rcu(event->rcu_batches);
5345 event->rcu_pending = 0;
5348 spin_lock_irqsave(&rb->event_lock, flags);
5349 list_add_rcu(&event->rb_entry, &rb->event_list);
5350 spin_unlock_irqrestore(&rb->event_lock, flags);
5354 * Avoid racing with perf_mmap_close(AUX): stop the event
5355 * before swizzling the event::rb pointer; if it's getting
5356 * unmapped, its aux_mmap_count will be 0 and it won't
5357 * restart. See the comment in __perf_pmu_output_stop().
5359 * Data will inevitably be lost when set_output is done in
5360 * mid-air, but then again, whoever does it like this is
5361 * not in for the data anyway.
5364 perf_event_stop(event, 0);
5366 rcu_assign_pointer(event->rb, rb);
5369 ring_buffer_put(old_rb);
5371 * Since we detached before setting the new rb, so that we
5372 * could attach the new rb, we could have missed a wakeup.
5375 wake_up_all(&event->waitq);
5379 static void ring_buffer_wakeup(struct perf_event *event)
5381 struct ring_buffer *rb;
5384 rb = rcu_dereference(event->rb);
5386 list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5387 wake_up_all(&event->waitq);
5392 struct ring_buffer *ring_buffer_get(struct perf_event *event)
5394 struct ring_buffer *rb;
5397 rb = rcu_dereference(event->rb);
5399 if (!atomic_inc_not_zero(&rb->refcount))
5407 void ring_buffer_put(struct ring_buffer *rb)
5409 if (!atomic_dec_and_test(&rb->refcount))
5412 WARN_ON_ONCE(!list_empty(&rb->event_list));
5414 call_rcu(&rb->rcu_head, rb_free_rcu);
5417 static void perf_mmap_open(struct vm_area_struct *vma)
5419 struct perf_event *event = vma->vm_file->private_data;
5421 atomic_inc(&event->mmap_count);
5422 atomic_inc(&event->rb->mmap_count);
5425 atomic_inc(&event->rb->aux_mmap_count);
5427 if (event->pmu->event_mapped)
5428 event->pmu->event_mapped(event, vma->vm_mm);
5431 static void perf_pmu_output_stop(struct perf_event *event);
5434 * A buffer can be mmap()ed multiple times; either directly through the same
5435 * event, or through other events by use of perf_event_set_output().
5437 * In order to undo the VM accounting done by perf_mmap() we need to destroy
5438 * the buffer here, where we still have a VM context. This means we need
5439 * to detach all events redirecting to us.
5441 static void perf_mmap_close(struct vm_area_struct *vma)
5443 struct perf_event *event = vma->vm_file->private_data;
5445 struct ring_buffer *rb = ring_buffer_get(event);
5446 struct user_struct *mmap_user = rb->mmap_user;
5447 int mmap_locked = rb->mmap_locked;
5448 unsigned long size = perf_data_size(rb);
5450 if (event->pmu->event_unmapped)
5451 event->pmu->event_unmapped(event, vma->vm_mm);
5454 * rb->aux_mmap_count will always drop before rb->mmap_count and
5455 * event->mmap_count, so it is ok to use event->mmap_mutex to
5456 * serialize with perf_mmap here.
5458 if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5459 atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5461 * Stop all AUX events that are writing to this buffer,
5462 * so that we can free its AUX pages and corresponding PMU
5463 * data. Note that after rb::aux_mmap_count dropped to zero,
5464 * they won't start any more (see perf_aux_output_begin()).
5466 perf_pmu_output_stop(event);
5468 /* now it's safe to free the pages */
5469 atomic_long_sub(rb->aux_nr_pages, &mmap_user->locked_vm);
5470 vma->vm_mm->pinned_vm -= rb->aux_mmap_locked;
5472 /* this has to be the last one */
5474 WARN_ON_ONCE(atomic_read(&rb->aux_refcount));
5476 mutex_unlock(&event->mmap_mutex);
5479 atomic_dec(&rb->mmap_count);
5481 if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5484 ring_buffer_attach(event, NULL);
5485 mutex_unlock(&event->mmap_mutex);
5487 /* If there's still other mmap()s of this buffer, we're done. */
5488 if (atomic_read(&rb->mmap_count))
5492 * No other mmap()s, detach from all other events that might redirect
5493 * into the now unreachable buffer. Somewhat complicated by the
5494 * fact that rb::event_lock otherwise nests inside mmap_mutex.
5498 list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5499 if (!atomic_long_inc_not_zero(&event->refcount)) {
5501 * This event is en-route to free_event() which will
5502 * detach it and remove it from the list.
5508 mutex_lock(&event->mmap_mutex);
5510 * Check we didn't race with perf_event_set_output() which can
5511 * swizzle the rb from under us while we were waiting to
5512 * acquire mmap_mutex.
5514 * If we find a different rb; ignore this event, a next
5515 * iteration will no longer find it on the list. We have to
5516 * still restart the iteration to make sure we're not now
5517 * iterating the wrong list.
5519 if (event->rb == rb)
5520 ring_buffer_attach(event, NULL);
5522 mutex_unlock(&event->mmap_mutex);
5526 * Restart the iteration; either we're on the wrong list or
5527 * destroyed its integrity by doing a deletion.
5534 * It could be there's still a few 0-ref events on the list; they'll
5535 * get cleaned up by free_event() -- they'll also still have their
5536 * ref on the rb and will free it whenever they are done with it.
5538 * Aside from that, this buffer is 'fully' detached and unmapped,
5539 * undo the VM accounting.
5542 atomic_long_sub((size >> PAGE_SHIFT) + 1, &mmap_user->locked_vm);
5543 vma->vm_mm->pinned_vm -= mmap_locked;
5544 free_uid(mmap_user);
5547 ring_buffer_put(rb); /* could be last */
5550 static const struct vm_operations_struct perf_mmap_vmops = {
5551 .open = perf_mmap_open,
5552 .close = perf_mmap_close, /* non mergeable */
5553 .fault = perf_mmap_fault,
5554 .page_mkwrite = perf_mmap_fault,
5557 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
5559 struct perf_event *event = file->private_data;
5560 unsigned long user_locked, user_lock_limit;
5561 struct user_struct *user = current_user();
5562 unsigned long locked, lock_limit;
5563 struct ring_buffer *rb = NULL;
5564 unsigned long vma_size;
5565 unsigned long nr_pages;
5566 long user_extra = 0, extra = 0;
5567 int ret = 0, flags = 0;
5570 * Don't allow mmap() of inherited per-task counters. This would
5571 * create a performance issue due to all children writing to the
5574 if (event->cpu == -1 && event->attr.inherit)
5577 if (!(vma->vm_flags & VM_SHARED))
5580 vma_size = vma->vm_end - vma->vm_start;
5582 if (vma->vm_pgoff == 0) {
5583 nr_pages = (vma_size / PAGE_SIZE) - 1;
5586 * AUX area mapping: if rb->aux_nr_pages != 0, it's already
5587 * mapped, all subsequent mappings should have the same size
5588 * and offset. Must be above the normal perf buffer.
5590 u64 aux_offset, aux_size;
5595 nr_pages = vma_size / PAGE_SIZE;
5597 mutex_lock(&event->mmap_mutex);
5604 aux_offset = READ_ONCE(rb->user_page->aux_offset);
5605 aux_size = READ_ONCE(rb->user_page->aux_size);
5607 if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
5610 if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
5613 /* already mapped with a different offset */
5614 if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
5617 if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
5620 /* already mapped with a different size */
5621 if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
5624 if (!is_power_of_2(nr_pages))
5627 if (!atomic_inc_not_zero(&rb->mmap_count))
5630 if (rb_has_aux(rb)) {
5631 atomic_inc(&rb->aux_mmap_count);
5636 atomic_set(&rb->aux_mmap_count, 1);
5637 user_extra = nr_pages;
5643 * If we have rb pages ensure they're a power-of-two number, so we
5644 * can do bitmasks instead of modulo.
5646 if (nr_pages != 0 && !is_power_of_2(nr_pages))
5649 if (vma_size != PAGE_SIZE * (1 + nr_pages))
5652 WARN_ON_ONCE(event->ctx->parent_ctx);
5654 mutex_lock(&event->mmap_mutex);
5656 if (event->rb->nr_pages != nr_pages) {
5661 if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
5663 * Raced against perf_mmap_close() through
5664 * perf_event_set_output(). Try again, hope for better
5667 mutex_unlock(&event->mmap_mutex);
5674 user_extra = nr_pages + 1;
5677 user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
5680 * Increase the limit linearly with more CPUs:
5682 user_lock_limit *= num_online_cpus();
5684 user_locked = atomic_long_read(&user->locked_vm) + user_extra;
5686 if (user_locked > user_lock_limit)
5687 extra = user_locked - user_lock_limit;
5689 lock_limit = rlimit(RLIMIT_MEMLOCK);
5690 lock_limit >>= PAGE_SHIFT;
5691 locked = vma->vm_mm->pinned_vm + extra;
5693 if ((locked > lock_limit) && perf_paranoid_tracepoint_raw() &&
5694 !capable(CAP_IPC_LOCK)) {
5699 WARN_ON(!rb && event->rb);
5701 if (vma->vm_flags & VM_WRITE)
5702 flags |= RING_BUFFER_WRITABLE;
5705 rb = rb_alloc(nr_pages,
5706 event->attr.watermark ? event->attr.wakeup_watermark : 0,
5714 atomic_set(&rb->mmap_count, 1);
5715 rb->mmap_user = get_current_user();
5716 rb->mmap_locked = extra;
5718 ring_buffer_attach(event, rb);
5720 perf_event_init_userpage(event);
5721 perf_event_update_userpage(event);
5723 ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
5724 event->attr.aux_watermark, flags);
5726 rb->aux_mmap_locked = extra;
5731 atomic_long_add(user_extra, &user->locked_vm);
5732 vma->vm_mm->pinned_vm += extra;
5734 atomic_inc(&event->mmap_count);
5736 atomic_dec(&rb->mmap_count);
5739 mutex_unlock(&event->mmap_mutex);
5742 * Since pinned accounting is per vm we cannot allow fork() to copy our
5745 vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
5746 vma->vm_ops = &perf_mmap_vmops;
5748 if (event->pmu->event_mapped)
5749 event->pmu->event_mapped(event, vma->vm_mm);
5754 static int perf_fasync(int fd, struct file *filp, int on)
5756 struct inode *inode = file_inode(filp);
5757 struct perf_event *event = filp->private_data;
5761 retval = fasync_helper(fd, filp, on, &event->fasync);
5762 inode_unlock(inode);
5770 static const struct file_operations perf_fops = {
5771 .llseek = no_llseek,
5772 .release = perf_release,
5775 .unlocked_ioctl = perf_ioctl,
5776 .compat_ioctl = perf_compat_ioctl,
5778 .fasync = perf_fasync,
5784 * If there's data, ensure we set the poll() state and publish everything
5785 * to user-space before waking everybody up.
5788 static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
5790 /* only the parent has fasync state */
5792 event = event->parent;
5793 return &event->fasync;
5796 void perf_event_wakeup(struct perf_event *event)
5798 ring_buffer_wakeup(event);
5800 if (event->pending_kill) {
5801 kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
5802 event->pending_kill = 0;
5806 static void perf_pending_event(struct irq_work *entry)
5808 struct perf_event *event = container_of(entry,
5809 struct perf_event, pending);
5812 rctx = perf_swevent_get_recursion_context();
5814 * If we 'fail' here, that's OK, it means recursion is already disabled
5815 * and we won't recurse 'further'.
5818 if (event->pending_disable) {
5819 event->pending_disable = 0;
5820 perf_event_disable_local(event);
5823 if (event->pending_wakeup) {
5824 event->pending_wakeup = 0;
5825 perf_event_wakeup(event);
5829 perf_swevent_put_recursion_context(rctx);
5833 * We assume there is only KVM supporting the callbacks.
5834 * Later on, we might change it to a list if there is
5835 * another virtualization implementation supporting the callbacks.
5837 struct perf_guest_info_callbacks *perf_guest_cbs;
5839 int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5841 perf_guest_cbs = cbs;
5844 EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
5846 int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
5848 perf_guest_cbs = NULL;
5851 EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
5854 perf_output_sample_regs(struct perf_output_handle *handle,
5855 struct pt_regs *regs, u64 mask)
5858 DECLARE_BITMAP(_mask, 64);
5860 bitmap_from_u64(_mask, mask);
5861 for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
5864 val = perf_reg_value(regs, bit);
5865 perf_output_put(handle, val);
5869 static void perf_sample_regs_user(struct perf_regs *regs_user,
5870 struct pt_regs *regs,
5871 struct pt_regs *regs_user_copy)
5873 if (user_mode(regs)) {
5874 regs_user->abi = perf_reg_abi(current);
5875 regs_user->regs = regs;
5876 } else if (current->mm) {
5877 perf_get_regs_user(regs_user, regs, regs_user_copy);
5879 regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
5880 regs_user->regs = NULL;
5884 static void perf_sample_regs_intr(struct perf_regs *regs_intr,
5885 struct pt_regs *regs)
5887 regs_intr->regs = regs;
5888 regs_intr->abi = perf_reg_abi(current);
5893 * Get remaining task size from user stack pointer.
5895 * It'd be better to take stack vma map and limit this more
5896 * precisly, but there's no way to get it safely under interrupt,
5897 * so using TASK_SIZE as limit.
5899 static u64 perf_ustack_task_size(struct pt_regs *regs)
5901 unsigned long addr = perf_user_stack_pointer(regs);
5903 if (!addr || addr >= TASK_SIZE)
5906 return TASK_SIZE - addr;
5910 perf_sample_ustack_size(u16 stack_size, u16 header_size,
5911 struct pt_regs *regs)
5915 /* No regs, no stack pointer, no dump. */
5920 * Check if we fit in with the requested stack size into the:
5922 * If we don't, we limit the size to the TASK_SIZE.
5924 * - remaining sample size
5925 * If we don't, we customize the stack size to
5926 * fit in to the remaining sample size.
5929 task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
5930 stack_size = min(stack_size, (u16) task_size);
5932 /* Current header size plus static size and dynamic size. */
5933 header_size += 2 * sizeof(u64);
5935 /* Do we fit in with the current stack dump size? */
5936 if ((u16) (header_size + stack_size) < header_size) {
5938 * If we overflow the maximum size for the sample,
5939 * we customize the stack dump size to fit in.
5941 stack_size = USHRT_MAX - header_size - sizeof(u64);
5942 stack_size = round_up(stack_size, sizeof(u64));
5949 perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
5950 struct pt_regs *regs)
5952 /* Case of a kernel thread, nothing to dump */
5955 perf_output_put(handle, size);
5965 * - the size requested by user or the best one we can fit
5966 * in to the sample max size
5968 * - user stack dump data
5970 * - the actual dumped size
5974 perf_output_put(handle, dump_size);
5977 sp = perf_user_stack_pointer(regs);
5980 rem = __output_copy_user(handle, (void *) sp, dump_size);
5982 dyn_size = dump_size - rem;
5984 perf_output_skip(handle, rem);
5987 perf_output_put(handle, dyn_size);
5991 static void __perf_event_header__init_id(struct perf_event_header *header,
5992 struct perf_sample_data *data,
5993 struct perf_event *event)
5995 u64 sample_type = event->attr.sample_type;
5997 data->type = sample_type;
5998 header->size += event->id_header_size;
6000 if (sample_type & PERF_SAMPLE_TID) {
6001 /* namespace issues */
6002 data->tid_entry.pid = perf_event_pid(event, current);
6003 data->tid_entry.tid = perf_event_tid(event, current);
6006 if (sample_type & PERF_SAMPLE_TIME)
6007 data->time = perf_event_clock(event);
6009 if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6010 data->id = primary_event_id(event);
6012 if (sample_type & PERF_SAMPLE_STREAM_ID)
6013 data->stream_id = event->id;
6015 if (sample_type & PERF_SAMPLE_CPU) {
6016 data->cpu_entry.cpu = raw_smp_processor_id();
6017 data->cpu_entry.reserved = 0;
6021 void perf_event_header__init_id(struct perf_event_header *header,
6022 struct perf_sample_data *data,
6023 struct perf_event *event)
6025 if (event->attr.sample_id_all)
6026 __perf_event_header__init_id(header, data, event);
6029 static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6030 struct perf_sample_data *data)
6032 u64 sample_type = data->type;
6034 if (sample_type & PERF_SAMPLE_TID)
6035 perf_output_put(handle, data->tid_entry);
6037 if (sample_type & PERF_SAMPLE_TIME)
6038 perf_output_put(handle, data->time);
6040 if (sample_type & PERF_SAMPLE_ID)
6041 perf_output_put(handle, data->id);
6043 if (sample_type & PERF_SAMPLE_STREAM_ID)
6044 perf_output_put(handle, data->stream_id);
6046 if (sample_type & PERF_SAMPLE_CPU)
6047 perf_output_put(handle, data->cpu_entry);
6049 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6050 perf_output_put(handle, data->id);
6053 void perf_event__output_id_sample(struct perf_event *event,
6054 struct perf_output_handle *handle,
6055 struct perf_sample_data *sample)
6057 if (event->attr.sample_id_all)
6058 __perf_event__output_id_sample(handle, sample);
6061 static void perf_output_read_one(struct perf_output_handle *handle,
6062 struct perf_event *event,
6063 u64 enabled, u64 running)
6065 u64 read_format = event->attr.read_format;
6069 values[n++] = perf_event_count(event);
6070 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6071 values[n++] = enabled +
6072 atomic64_read(&event->child_total_time_enabled);
6074 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6075 values[n++] = running +
6076 atomic64_read(&event->child_total_time_running);
6078 if (read_format & PERF_FORMAT_ID)
6079 values[n++] = primary_event_id(event);
6081 __output_copy(handle, values, n * sizeof(u64));
6084 static void perf_output_read_group(struct perf_output_handle *handle,
6085 struct perf_event *event,
6086 u64 enabled, u64 running)
6088 struct perf_event *leader = event->group_leader, *sub;
6089 u64 read_format = event->attr.read_format;
6093 values[n++] = 1 + leader->nr_siblings;
6095 if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6096 values[n++] = enabled;
6098 if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6099 values[n++] = running;
6101 if ((leader != event) &&
6102 (leader->state == PERF_EVENT_STATE_ACTIVE))
6103 leader->pmu->read(leader);
6105 values[n++] = perf_event_count(leader);
6106 if (read_format & PERF_FORMAT_ID)
6107 values[n++] = primary_event_id(leader);
6109 __output_copy(handle, values, n * sizeof(u64));
6111 for_each_sibling_event(sub, leader) {
6114 if ((sub != event) &&
6115 (sub->state == PERF_EVENT_STATE_ACTIVE))
6116 sub->pmu->read(sub);
6118 values[n++] = perf_event_count(sub);
6119 if (read_format & PERF_FORMAT_ID)
6120 values[n++] = primary_event_id(sub);
6122 __output_copy(handle, values, n * sizeof(u64));
6126 #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6127 PERF_FORMAT_TOTAL_TIME_RUNNING)
6130 * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6132 * The problem is that its both hard and excessively expensive to iterate the
6133 * child list, not to mention that its impossible to IPI the children running
6134 * on another CPU, from interrupt/NMI context.
6136 static void perf_output_read(struct perf_output_handle *handle,
6137 struct perf_event *event)
6139 u64 enabled = 0, running = 0, now;
6140 u64 read_format = event->attr.read_format;
6143 * compute total_time_enabled, total_time_running
6144 * based on snapshot values taken when the event
6145 * was last scheduled in.
6147 * we cannot simply called update_context_time()
6148 * because of locking issue as we are called in
6151 if (read_format & PERF_FORMAT_TOTAL_TIMES)
6152 calc_timer_values(event, &now, &enabled, &running);
6154 if (event->attr.read_format & PERF_FORMAT_GROUP)
6155 perf_output_read_group(handle, event, enabled, running);
6157 perf_output_read_one(handle, event, enabled, running);
6160 void perf_output_sample(struct perf_output_handle *handle,
6161 struct perf_event_header *header,
6162 struct perf_sample_data *data,
6163 struct perf_event *event)
6165 u64 sample_type = data->type;
6167 perf_output_put(handle, *header);
6169 if (sample_type & PERF_SAMPLE_IDENTIFIER)
6170 perf_output_put(handle, data->id);
6172 if (sample_type & PERF_SAMPLE_IP)
6173 perf_output_put(handle, data->ip);
6175 if (sample_type & PERF_SAMPLE_TID)
6176 perf_output_put(handle, data->tid_entry);
6178 if (sample_type & PERF_SAMPLE_TIME)
6179 perf_output_put(handle, data->time);
6181 if (sample_type & PERF_SAMPLE_ADDR)
6182 perf_output_put(handle, data->addr);
6184 if (sample_type & PERF_SAMPLE_ID)
6185 perf_output_put(handle, data->id);
6187 if (sample_type & PERF_SAMPLE_STREAM_ID)
6188 perf_output_put(handle, data->stream_id);
6190 if (sample_type & PERF_SAMPLE_CPU)
6191 perf_output_put(handle, data->cpu_entry);
6193 if (sample_type & PERF_SAMPLE_PERIOD)
6194 perf_output_put(handle, data->period);
6196 if (sample_type & PERF_SAMPLE_READ)
6197 perf_output_read(handle, event);
6199 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6202 size += data->callchain->nr;
6203 size *= sizeof(u64);
6204 __output_copy(handle, data->callchain, size);
6207 if (sample_type & PERF_SAMPLE_RAW) {
6208 struct perf_raw_record *raw = data->raw;
6211 struct perf_raw_frag *frag = &raw->frag;
6213 perf_output_put(handle, raw->size);
6216 __output_custom(handle, frag->copy,
6217 frag->data, frag->size);
6219 __output_copy(handle, frag->data,
6222 if (perf_raw_frag_last(frag))
6227 __output_skip(handle, NULL, frag->pad);
6233 .size = sizeof(u32),
6236 perf_output_put(handle, raw);
6240 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6241 if (data->br_stack) {
6244 size = data->br_stack->nr
6245 * sizeof(struct perf_branch_entry);
6247 perf_output_put(handle, data->br_stack->nr);
6248 perf_output_copy(handle, data->br_stack->entries, size);
6251 * we always store at least the value of nr
6254 perf_output_put(handle, nr);
6258 if (sample_type & PERF_SAMPLE_REGS_USER) {
6259 u64 abi = data->regs_user.abi;
6262 * If there are no regs to dump, notice it through
6263 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6265 perf_output_put(handle, abi);
6268 u64 mask = event->attr.sample_regs_user;
6269 perf_output_sample_regs(handle,
6270 data->regs_user.regs,
6275 if (sample_type & PERF_SAMPLE_STACK_USER) {
6276 perf_output_sample_ustack(handle,
6277 data->stack_user_size,
6278 data->regs_user.regs);
6281 if (sample_type & PERF_SAMPLE_WEIGHT)
6282 perf_output_put(handle, data->weight);
6284 if (sample_type & PERF_SAMPLE_DATA_SRC)
6285 perf_output_put(handle, data->data_src.val);
6287 if (sample_type & PERF_SAMPLE_TRANSACTION)
6288 perf_output_put(handle, data->txn);
6290 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6291 u64 abi = data->regs_intr.abi;
6293 * If there are no regs to dump, notice it through
6294 * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6296 perf_output_put(handle, abi);
6299 u64 mask = event->attr.sample_regs_intr;
6301 perf_output_sample_regs(handle,
6302 data->regs_intr.regs,
6307 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6308 perf_output_put(handle, data->phys_addr);
6310 if (!event->attr.watermark) {
6311 int wakeup_events = event->attr.wakeup_events;
6313 if (wakeup_events) {
6314 struct ring_buffer *rb = handle->rb;
6315 int events = local_inc_return(&rb->events);
6317 if (events >= wakeup_events) {
6318 local_sub(wakeup_events, &rb->events);
6319 local_inc(&rb->wakeup);
6325 static u64 perf_virt_to_phys(u64 virt)
6328 struct page *p = NULL;
6333 if (virt >= TASK_SIZE) {
6334 /* If it's vmalloc()d memory, leave phys_addr as 0 */
6335 if (virt_addr_valid((void *)(uintptr_t)virt) &&
6336 !(virt >= VMALLOC_START && virt < VMALLOC_END))
6337 phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
6340 * Walking the pages tables for user address.
6341 * Interrupts are disabled, so it prevents any tear down
6342 * of the page tables.
6343 * Try IRQ-safe __get_user_pages_fast first.
6344 * If failed, leave phys_addr as 0.
6346 if ((current->mm != NULL) &&
6347 (__get_user_pages_fast(virt, 1, 0, &p) == 1))
6348 phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
6357 static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
6359 struct perf_callchain_entry *
6360 perf_callchain(struct perf_event *event, struct pt_regs *regs)
6362 bool kernel = !event->attr.exclude_callchain_kernel;
6363 bool user = !event->attr.exclude_callchain_user;
6364 /* Disallow cross-task user callchains. */
6365 bool crosstask = event->ctx->task && event->ctx->task != current;
6366 const u32 max_stack = event->attr.sample_max_stack;
6367 struct perf_callchain_entry *callchain;
6369 if (!kernel && !user)
6370 return &__empty_callchain;
6372 callchain = get_perf_callchain(regs, 0, kernel, user,
6373 max_stack, crosstask, true);
6374 return callchain ?: &__empty_callchain;
6377 void perf_prepare_sample(struct perf_event_header *header,
6378 struct perf_sample_data *data,
6379 struct perf_event *event,
6380 struct pt_regs *regs)
6382 u64 sample_type = event->attr.sample_type;
6384 header->type = PERF_RECORD_SAMPLE;
6385 header->size = sizeof(*header) + event->header_size;
6388 header->misc |= perf_misc_flags(regs);
6390 __perf_event_header__init_id(header, data, event);
6392 if (sample_type & PERF_SAMPLE_IP)
6393 data->ip = perf_instruction_pointer(regs);
6395 if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6398 if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
6399 data->callchain = perf_callchain(event, regs);
6401 size += data->callchain->nr;
6403 header->size += size * sizeof(u64);
6406 if (sample_type & PERF_SAMPLE_RAW) {
6407 struct perf_raw_record *raw = data->raw;
6411 struct perf_raw_frag *frag = &raw->frag;
6416 if (perf_raw_frag_last(frag))
6421 size = round_up(sum + sizeof(u32), sizeof(u64));
6422 raw->size = size - sizeof(u32);
6423 frag->pad = raw->size - sum;
6428 header->size += size;
6431 if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6432 int size = sizeof(u64); /* nr */
6433 if (data->br_stack) {
6434 size += data->br_stack->nr
6435 * sizeof(struct perf_branch_entry);
6437 header->size += size;
6440 if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
6441 perf_sample_regs_user(&data->regs_user, regs,
6442 &data->regs_user_copy);
6444 if (sample_type & PERF_SAMPLE_REGS_USER) {
6445 /* regs dump ABI info */
6446 int size = sizeof(u64);
6448 if (data->regs_user.regs) {
6449 u64 mask = event->attr.sample_regs_user;
6450 size += hweight64(mask) * sizeof(u64);
6453 header->size += size;
6456 if (sample_type & PERF_SAMPLE_STACK_USER) {
6458 * Either we need PERF_SAMPLE_STACK_USER bit to be allways
6459 * processed as the last one or have additional check added
6460 * in case new sample type is added, because we could eat
6461 * up the rest of the sample size.
6463 u16 stack_size = event->attr.sample_stack_user;
6464 u16 size = sizeof(u64);
6466 stack_size = perf_sample_ustack_size(stack_size, header->size,
6467 data->regs_user.regs);
6470 * If there is something to dump, add space for the dump
6471 * itself and for the field that tells the dynamic size,
6472 * which is how many have been actually dumped.
6475 size += sizeof(u64) + stack_size;
6477 data->stack_user_size = stack_size;
6478 header->size += size;
6481 if (sample_type & PERF_SAMPLE_REGS_INTR) {
6482 /* regs dump ABI info */
6483 int size = sizeof(u64);
6485 perf_sample_regs_intr(&data->regs_intr, regs);
6487 if (data->regs_intr.regs) {
6488 u64 mask = event->attr.sample_regs_intr;
6490 size += hweight64(mask) * sizeof(u64);
6493 header->size += size;
6496 if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6497 data->phys_addr = perf_virt_to_phys(data->addr);
6500 static __always_inline void
6501 __perf_event_output(struct perf_event *event,
6502 struct perf_sample_data *data,
6503 struct pt_regs *regs,
6504 int (*output_begin)(struct perf_output_handle *,
6505 struct perf_event *,
6508 struct perf_output_handle handle;
6509 struct perf_event_header header;
6511 /* protect the callchain buffers */
6514 perf_prepare_sample(&header, data, event, regs);
6516 if (output_begin(&handle, event, header.size))
6519 perf_output_sample(&handle, &header, data, event);
6521 perf_output_end(&handle);
6528 perf_event_output_forward(struct perf_event *event,
6529 struct perf_sample_data *data,
6530 struct pt_regs *regs)
6532 __perf_event_output(event, data, regs, perf_output_begin_forward);
6536 perf_event_output_backward(struct perf_event *event,
6537 struct perf_sample_data *data,
6538 struct pt_regs *regs)
6540 __perf_event_output(event, data, regs, perf_output_begin_backward);
6544 perf_event_output(struct perf_event *event,
6545 struct perf_sample_data *data,
6546 struct pt_regs *regs)
6548 __perf_event_output(event, data, regs, perf_output_begin);
6555 struct perf_read_event {
6556 struct perf_event_header header;
6563 perf_event_read_event(struct perf_event *event,
6564 struct task_struct *task)
6566 struct perf_output_handle handle;
6567 struct perf_sample_data sample;
6568 struct perf_read_event read_event = {
6570 .type = PERF_RECORD_READ,
6572 .size = sizeof(read_event) + event->read_size,
6574 .pid = perf_event_pid(event, task),
6575 .tid = perf_event_tid(event, task),
6579 perf_event_header__init_id(&read_event.header, &sample, event);
6580 ret = perf_output_begin(&handle, event, read_event.header.size);
6584 perf_output_put(&handle, read_event);
6585 perf_output_read(&handle, event);
6586 perf_event__output_id_sample(event, &handle, &sample);
6588 perf_output_end(&handle);
6591 typedef void (perf_iterate_f)(struct perf_event *event, void *data);
6594 perf_iterate_ctx(struct perf_event_context *ctx,
6595 perf_iterate_f output,
6596 void *data, bool all)
6598 struct perf_event *event;
6600 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
6602 if (event->state < PERF_EVENT_STATE_INACTIVE)
6604 if (!event_filter_match(event))
6608 output(event, data);
6612 static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
6614 struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
6615 struct perf_event *event;
6617 list_for_each_entry_rcu(event, &pel->list, sb_list) {
6619 * Skip events that are not fully formed yet; ensure that
6620 * if we observe event->ctx, both event and ctx will be
6621 * complete enough. See perf_install_in_context().
6623 if (!smp_load_acquire(&event->ctx))
6626 if (event->state < PERF_EVENT_STATE_INACTIVE)
6628 if (!event_filter_match(event))
6630 output(event, data);
6635 * Iterate all events that need to receive side-band events.
6637 * For new callers; ensure that account_pmu_sb_event() includes
6638 * your event, otherwise it might not get delivered.
6641 perf_iterate_sb(perf_iterate_f output, void *data,
6642 struct perf_event_context *task_ctx)
6644 struct perf_event_context *ctx;
6651 * If we have task_ctx != NULL we only notify the task context itself.
6652 * The task_ctx is set only for EXIT events before releasing task
6656 perf_iterate_ctx(task_ctx, output, data, false);
6660 perf_iterate_sb_cpu(output, data);
6662 for_each_task_context_nr(ctxn) {
6663 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
6665 perf_iterate_ctx(ctx, output, data, false);
6673 * Clear all file-based filters at exec, they'll have to be
6674 * re-instated when/if these objects are mmapped again.
6676 static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
6678 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
6679 struct perf_addr_filter *filter;
6680 unsigned int restart = 0, count = 0;
6681 unsigned long flags;
6683 if (!has_addr_filter(event))
6686 raw_spin_lock_irqsave(&ifh->lock, flags);
6687 list_for_each_entry(filter, &ifh->list, entry) {
6688 if (filter->path.dentry) {
6689 event->addr_filters_offs[count] = 0;
6697 event->addr_filters_gen++;
6698 raw_spin_unlock_irqrestore(&ifh->lock, flags);
6701 perf_event_stop(event, 1);
6704 void perf_event_exec(void)
6706 struct perf_event_context *ctx;
6710 for_each_task_context_nr(ctxn) {
6711 ctx = current->perf_event_ctxp[ctxn];
6715 perf_event_enable_on_exec(ctxn);
6717 perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
6723 struct remote_output {
6724 struct ring_buffer *rb;
6728 static void __perf_event_output_stop(struct perf_event *event, void *data)
6730 struct perf_event *parent = event->parent;
6731 struct remote_output *ro = data;
6732 struct ring_buffer *rb = ro->rb;
6733 struct stop_event_data sd = {
6737 if (!has_aux(event))
6744 * In case of inheritance, it will be the parent that links to the
6745 * ring-buffer, but it will be the child that's actually using it.
6747 * We are using event::rb to determine if the event should be stopped,
6748 * however this may race with ring_buffer_attach() (through set_output),
6749 * which will make us skip the event that actually needs to be stopped.
6750 * So ring_buffer_attach() has to stop an aux event before re-assigning
6753 if (rcu_dereference(parent->rb) == rb)
6754 ro->err = __perf_event_stop(&sd);
6757 static int __perf_pmu_output_stop(void *info)
6759 struct perf_event *event = info;
6760 struct pmu *pmu = event->pmu;
6761 struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
6762 struct remote_output ro = {
6767 perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
6768 if (cpuctx->task_ctx)
6769 perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
6776 static void perf_pmu_output_stop(struct perf_event *event)
6778 struct perf_event *iter;
6783 list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
6785 * For per-CPU events, we need to make sure that neither they
6786 * nor their children are running; for cpu==-1 events it's
6787 * sufficient to stop the event itself if it's active, since
6788 * it can't have children.
6792 cpu = READ_ONCE(iter->oncpu);
6797 err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
6798 if (err == -EAGAIN) {
6807 * task tracking -- fork/exit
6809 * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
6812 struct perf_task_event {
6813 struct task_struct *task;
6814 struct perf_event_context *task_ctx;
6817 struct perf_event_header header;
6827 static int perf_event_task_match(struct perf_event *event)
6829 return event->attr.comm || event->attr.mmap ||
6830 event->attr.mmap2 || event->attr.mmap_data ||
6834 static void perf_event_task_output(struct perf_event *event,
6837 struct perf_task_event *task_event = data;
6838 struct perf_output_handle handle;
6839 struct perf_sample_data sample;
6840 struct task_struct *task = task_event->task;
6841 int ret, size = task_event->event_id.header.size;
6843 if (!perf_event_task_match(event))
6846 perf_event_header__init_id(&task_event->event_id.header, &sample, event);
6848 ret = perf_output_begin(&handle, event,
6849 task_event->event_id.header.size);
6853 task_event->event_id.pid = perf_event_pid(event, task);
6854 task_event->event_id.ppid = perf_event_pid(event, current);
6856 task_event->event_id.tid = perf_event_tid(event, task);
6857 task_event->event_id.ptid = perf_event_tid(event, current);
6859 task_event->event_id.time = perf_event_clock(event);
6861 perf_output_put(&handle, task_event->event_id);
6863 perf_event__output_id_sample(event, &handle, &sample);
6865 perf_output_end(&handle);
6867 task_event->event_id.header.size = size;
6870 static void perf_event_task(struct task_struct *task,
6871 struct perf_event_context *task_ctx,
6874 struct perf_task_event task_event;
6876 if (!atomic_read(&nr_comm_events) &&
6877 !atomic_read(&nr_mmap_events) &&
6878 !atomic_read(&nr_task_events))
6881 task_event = (struct perf_task_event){
6883 .task_ctx = task_ctx,
6886 .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
6888 .size = sizeof(task_event.event_id),
6898 perf_iterate_sb(perf_event_task_output,
6903 void perf_event_fork(struct task_struct *task)
6905 perf_event_task(task, NULL, 1);
6906 perf_event_namespaces(task);
6913 struct perf_comm_event {
6914 struct task_struct *task;
6919 struct perf_event_header header;
6926 static int perf_event_comm_match(struct perf_event *event)
6928 return event->attr.comm;
6931 static void perf_event_comm_output(struct perf_event *event,
6934 struct perf_comm_event *comm_event = data;
6935 struct perf_output_handle handle;
6936 struct perf_sample_data sample;
6937 int size = comm_event->event_id.header.size;
6940 if (!perf_event_comm_match(event))
6943 perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
6944 ret = perf_output_begin(&handle, event,
6945 comm_event->event_id.header.size);
6950 comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
6951 comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
6953 perf_output_put(&handle, comm_event->event_id);
6954 __output_copy(&handle, comm_event->comm,
6955 comm_event->comm_size);
6957 perf_event__output_id_sample(event, &handle, &sample);
6959 perf_output_end(&handle);
6961 comm_event->event_id.header.size = size;
6964 static void perf_event_comm_event(struct perf_comm_event *comm_event)
6966 char comm[TASK_COMM_LEN];
6969 memset(comm, 0, sizeof(comm));
6970 strlcpy(comm, comm_event->task->comm, sizeof(comm));
6971 size = ALIGN(strlen(comm)+1, sizeof(u64));
6973 comm_event->comm = comm;
6974 comm_event->comm_size = size;
6976 comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
6978 perf_iterate_sb(perf_event_comm_output,
6983 void perf_event_comm(struct task_struct *task, bool exec)
6985 struct perf_comm_event comm_event;
6987 if (!atomic_read(&nr_comm_events))
6990 comm_event = (struct perf_comm_event){
6996 .type = PERF_RECORD_COMM,
6997 .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7005 perf_event_comm_event(&comm_event);
7009 * namespaces tracking
7012 struct perf_namespaces_event {
7013 struct task_struct *task;
7016 struct perf_event_header header;
7021 struct perf_ns_link_info link_info[NR_NAMESPACES];
7025 static int perf_event_namespaces_match(struct perf_event *event)
7027 return event->attr.namespaces;
7030 static void perf_event_namespaces_output(struct perf_event *event,
7033 struct perf_namespaces_event *namespaces_event = data;
7034 struct perf_output_handle handle;
7035 struct perf_sample_data sample;
7036 u16 header_size = namespaces_event->event_id.header.size;
7039 if (!perf_event_namespaces_match(event))
7042 perf_event_header__init_id(&namespaces_event->event_id.header,
7044 ret = perf_output_begin(&handle, event,
7045 namespaces_event->event_id.header.size);
7049 namespaces_event->event_id.pid = perf_event_pid(event,
7050 namespaces_event->task);
7051 namespaces_event->event_id.tid = perf_event_tid(event,
7052 namespaces_event->task);
7054 perf_output_put(&handle, namespaces_event->event_id);
7056 perf_event__output_id_sample(event, &handle, &sample);
7058 perf_output_end(&handle);
7060 namespaces_event->event_id.header.size = header_size;
7063 static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7064 struct task_struct *task,
7065 const struct proc_ns_operations *ns_ops)
7067 struct path ns_path;
7068 struct inode *ns_inode;
7071 error = ns_get_path(&ns_path, task, ns_ops);
7073 ns_inode = ns_path.dentry->d_inode;
7074 ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7075 ns_link_info->ino = ns_inode->i_ino;
7080 void perf_event_namespaces(struct task_struct *task)
7082 struct perf_namespaces_event namespaces_event;
7083 struct perf_ns_link_info *ns_link_info;
7085 if (!atomic_read(&nr_namespaces_events))
7088 namespaces_event = (struct perf_namespaces_event){
7092 .type = PERF_RECORD_NAMESPACES,
7094 .size = sizeof(namespaces_event.event_id),
7098 .nr_namespaces = NR_NAMESPACES,
7099 /* .link_info[NR_NAMESPACES] */
7103 ns_link_info = namespaces_event.event_id.link_info;
7105 perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7106 task, &mntns_operations);
7108 #ifdef CONFIG_USER_NS
7109 perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7110 task, &userns_operations);
7112 #ifdef CONFIG_NET_NS
7113 perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7114 task, &netns_operations);
7116 #ifdef CONFIG_UTS_NS
7117 perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7118 task, &utsns_operations);
7120 #ifdef CONFIG_IPC_NS
7121 perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7122 task, &ipcns_operations);
7124 #ifdef CONFIG_PID_NS
7125 perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7126 task, &pidns_operations);
7128 #ifdef CONFIG_CGROUPS
7129 perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7130 task, &cgroupns_operations);
7133 perf_iterate_sb(perf_event_namespaces_output,
7142 struct perf_mmap_event {
7143 struct vm_area_struct *vma;
7145 const char *file_name;
7153 struct perf_event_header header;
7163 static int perf_event_mmap_match(struct perf_event *event,
7166 struct perf_mmap_event *mmap_event = data;
7167 struct vm_area_struct *vma = mmap_event->vma;
7168 int executable = vma->vm_flags & VM_EXEC;
7170 return (!executable && event->attr.mmap_data) ||
7171 (executable && (event->attr.mmap || event->attr.mmap2));
7174 static void perf_event_mmap_output(struct perf_event *event,
7177 struct perf_mmap_event *mmap_event = data;
7178 struct perf_output_handle handle;
7179 struct perf_sample_data sample;
7180 int size = mmap_event->event_id.header.size;
7183 if (!perf_event_mmap_match(event, data))
7186 if (event->attr.mmap2) {
7187 mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
7188 mmap_event->event_id.header.size += sizeof(mmap_event->maj);
7189 mmap_event->event_id.header.size += sizeof(mmap_event->min);
7190 mmap_event->event_id.header.size += sizeof(mmap_event->ino);
7191 mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
7192 mmap_event->event_id.header.size += sizeof(mmap_event->prot);
7193 mmap_event->event_id.header.size += sizeof(mmap_event->flags);
7196 perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
7197 ret = perf_output_begin(&handle, event,
7198 mmap_event->event_id.header.size);
7202 mmap_event->event_id.pid = perf_event_pid(event, current);
7203 mmap_event->event_id.tid = perf_event_tid(event, current);
7205 perf_output_put(&handle, mmap_event->event_id);
7207 if (event->attr.mmap2) {
7208 perf_output_put(&handle, mmap_event->maj);
7209 perf_output_put(&handle, mmap_event->min);
7210 perf_output_put(&handle, mmap_event->ino);
7211 perf_output_put(&handle, mmap_event->ino_generation);
7212 perf_output_put(&handle, mmap_event->prot);
7213 perf_output_put(&handle, mmap_event->flags);
7216 __output_copy(&handle, mmap_event->file_name,
7217 mmap_event->file_size);
7219 perf_event__output_id_sample(event, &handle, &sample);
7221 perf_output_end(&handle);
7223 mmap_event->event_id.header.size = size;
7226 static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
7228 struct vm_area_struct *vma = mmap_event->vma;
7229 struct file *file = vma->vm_file;
7230 int maj = 0, min = 0;
7231 u64 ino = 0, gen = 0;
7232 u32 prot = 0, flags = 0;
7238 if (vma->vm_flags & VM_READ)
7240 if (vma->vm_flags & VM_WRITE)
7242 if (vma->vm_flags & VM_EXEC)
7245 if (vma->vm_flags & VM_MAYSHARE)
7248 flags = MAP_PRIVATE;
7250 if (vma->vm_flags & VM_DENYWRITE)
7251 flags |= MAP_DENYWRITE;
7252 if (vma->vm_flags & VM_MAYEXEC)
7253 flags |= MAP_EXECUTABLE;
7254 if (vma->vm_flags & VM_LOCKED)
7255 flags |= MAP_LOCKED;
7256 if (vma->vm_flags & VM_HUGETLB)
7257 flags |= MAP_HUGETLB;
7260 struct inode *inode;
7263 buf = kmalloc(PATH_MAX, GFP_KERNEL);
7269 * d_path() works from the end of the rb backwards, so we
7270 * need to add enough zero bytes after the string to handle
7271 * the 64bit alignment we do later.
7273 name = file_path(file, buf, PATH_MAX - sizeof(u64));
7278 inode = file_inode(vma->vm_file);
7279 dev = inode->i_sb->s_dev;
7281 gen = inode->i_generation;
7287 if (vma->vm_ops && vma->vm_ops->name) {
7288 name = (char *) vma->vm_ops->name(vma);
7293 name = (char *)arch_vma_name(vma);
7297 if (vma->vm_start <= vma->vm_mm->start_brk &&
7298 vma->vm_end >= vma->vm_mm->brk) {
7302 if (vma->vm_start <= vma->vm_mm->start_stack &&
7303 vma->vm_end >= vma->vm_mm->start_stack) {
7313 strlcpy(tmp, name, sizeof(tmp));
7317 * Since our buffer works in 8 byte units we need to align our string
7318 * size to a multiple of 8. However, we must guarantee the tail end is
7319 * zero'd out to avoid leaking random bits to userspace.
7321 size = strlen(name)+1;
7322 while (!IS_ALIGNED(size, sizeof(u64)))
7323 name[size++] = '\0';
7325 mmap_event->file_name = name;
7326 mmap_event->file_size = size;
7327 mmap_event->maj = maj;
7328 mmap_event->min = min;
7329 mmap_event->ino = ino;
7330 mmap_event->ino_generation = gen;
7331 mmap_event->prot = prot;
7332 mmap_event->flags = flags;
7334 if (!(vma->vm_flags & VM_EXEC))
7335 mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
7337 mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
7339 perf_iterate_sb(perf_event_mmap_output,
7347 * Check whether inode and address range match filter criteria.
7349 static bool perf_addr_filter_match(struct perf_addr_filter *filter,
7350 struct file *file, unsigned long offset,
7353 /* d_inode(NULL) won't be equal to any mapped user-space file */
7354 if (!filter->path.dentry)
7357 if (d_inode(filter->path.dentry) != file_inode(file))
7360 if (filter->offset > offset + size)
7363 if (filter->offset + filter->size < offset)
7369 static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
7371 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7372 struct vm_area_struct *vma = data;
7373 unsigned long off = vma->vm_pgoff << PAGE_SHIFT, flags;
7374 struct file *file = vma->vm_file;
7375 struct perf_addr_filter *filter;
7376 unsigned int restart = 0, count = 0;
7378 if (!has_addr_filter(event))
7384 raw_spin_lock_irqsave(&ifh->lock, flags);
7385 list_for_each_entry(filter, &ifh->list, entry) {
7386 if (perf_addr_filter_match(filter, file, off,
7387 vma->vm_end - vma->vm_start)) {
7388 event->addr_filters_offs[count] = vma->vm_start;
7396 event->addr_filters_gen++;
7397 raw_spin_unlock_irqrestore(&ifh->lock, flags);
7400 perf_event_stop(event, 1);
7404 * Adjust all task's events' filters to the new vma
7406 static void perf_addr_filters_adjust(struct vm_area_struct *vma)
7408 struct perf_event_context *ctx;
7412 * Data tracing isn't supported yet and as such there is no need
7413 * to keep track of anything that isn't related to executable code:
7415 if (!(vma->vm_flags & VM_EXEC))
7419 for_each_task_context_nr(ctxn) {
7420 ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7424 perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
7429 void perf_event_mmap(struct vm_area_struct *vma)
7431 struct perf_mmap_event mmap_event;
7433 if (!atomic_read(&nr_mmap_events))
7436 mmap_event = (struct perf_mmap_event){
7442 .type = PERF_RECORD_MMAP,
7443 .misc = PERF_RECORD_MISC_USER,
7448 .start = vma->vm_start,
7449 .len = vma->vm_end - vma->vm_start,
7450 .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
7452 /* .maj (attr_mmap2 only) */
7453 /* .min (attr_mmap2 only) */
7454 /* .ino (attr_mmap2 only) */
7455 /* .ino_generation (attr_mmap2 only) */
7456 /* .prot (attr_mmap2 only) */
7457 /* .flags (attr_mmap2 only) */
7460 perf_addr_filters_adjust(vma);
7461 perf_event_mmap_event(&mmap_event);
7464 void perf_event_aux_event(struct perf_event *event, unsigned long head,
7465 unsigned long size, u64 flags)
7467 struct perf_output_handle handle;
7468 struct perf_sample_data sample;
7469 struct perf_aux_event {
7470 struct perf_event_header header;
7476 .type = PERF_RECORD_AUX,
7478 .size = sizeof(rec),
7486 perf_event_header__init_id(&rec.header, &sample, event);
7487 ret = perf_output_begin(&handle, event, rec.header.size);
7492 perf_output_put(&handle, rec);
7493 perf_event__output_id_sample(event, &handle, &sample);
7495 perf_output_end(&handle);
7499 * Lost/dropped samples logging
7501 void perf_log_lost_samples(struct perf_event *event, u64 lost)
7503 struct perf_output_handle handle;
7504 struct perf_sample_data sample;
7508 struct perf_event_header header;
7510 } lost_samples_event = {
7512 .type = PERF_RECORD_LOST_SAMPLES,
7514 .size = sizeof(lost_samples_event),
7519 perf_event_header__init_id(&lost_samples_event.header, &sample, event);
7521 ret = perf_output_begin(&handle, event,
7522 lost_samples_event.header.size);
7526 perf_output_put(&handle, lost_samples_event);
7527 perf_event__output_id_sample(event, &handle, &sample);
7528 perf_output_end(&handle);
7532 * context_switch tracking
7535 struct perf_switch_event {
7536 struct task_struct *task;
7537 struct task_struct *next_prev;
7540 struct perf_event_header header;
7546 static int perf_event_switch_match(struct perf_event *event)
7548 return event->attr.context_switch;
7551 static void perf_event_switch_output(struct perf_event *event, void *data)
7553 struct perf_switch_event *se = data;
7554 struct perf_output_handle handle;
7555 struct perf_sample_data sample;
7558 if (!perf_event_switch_match(event))
7561 /* Only CPU-wide events are allowed to see next/prev pid/tid */
7562 if (event->ctx->task) {
7563 se->event_id.header.type = PERF_RECORD_SWITCH;
7564 se->event_id.header.size = sizeof(se->event_id.header);
7566 se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
7567 se->event_id.header.size = sizeof(se->event_id);
7568 se->event_id.next_prev_pid =
7569 perf_event_pid(event, se->next_prev);
7570 se->event_id.next_prev_tid =
7571 perf_event_tid(event, se->next_prev);
7574 perf_event_header__init_id(&se->event_id.header, &sample, event);
7576 ret = perf_output_begin(&handle, event, se->event_id.header.size);
7580 if (event->ctx->task)
7581 perf_output_put(&handle, se->event_id.header);
7583 perf_output_put(&handle, se->event_id);
7585 perf_event__output_id_sample(event, &handle, &sample);
7587 perf_output_end(&handle);
7590 static void perf_event_switch(struct task_struct *task,
7591 struct task_struct *next_prev, bool sched_in)
7593 struct perf_switch_event switch_event;
7595 /* N.B. caller checks nr_switch_events != 0 */
7597 switch_event = (struct perf_switch_event){
7599 .next_prev = next_prev,
7603 .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
7606 /* .next_prev_pid */
7607 /* .next_prev_tid */
7611 if (!sched_in && task->state == TASK_RUNNING)
7612 switch_event.event_id.header.misc |=
7613 PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
7615 perf_iterate_sb(perf_event_switch_output,
7621 * IRQ throttle logging
7624 static void perf_log_throttle(struct perf_event *event, int enable)
7626 struct perf_output_handle handle;
7627 struct perf_sample_data sample;
7631 struct perf_event_header header;
7635 } throttle_event = {
7637 .type = PERF_RECORD_THROTTLE,
7639 .size = sizeof(throttle_event),
7641 .time = perf_event_clock(event),
7642 .id = primary_event_id(event),
7643 .stream_id = event->id,
7647 throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
7649 perf_event_header__init_id(&throttle_event.header, &sample, event);
7651 ret = perf_output_begin(&handle, event,
7652 throttle_event.header.size);
7656 perf_output_put(&handle, throttle_event);
7657 perf_event__output_id_sample(event, &handle, &sample);
7658 perf_output_end(&handle);
7661 void perf_event_itrace_started(struct perf_event *event)
7663 event->attach_state |= PERF_ATTACH_ITRACE;
7666 static void perf_log_itrace_start(struct perf_event *event)
7668 struct perf_output_handle handle;
7669 struct perf_sample_data sample;
7670 struct perf_aux_event {
7671 struct perf_event_header header;
7678 event = event->parent;
7680 if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
7681 event->attach_state & PERF_ATTACH_ITRACE)
7684 rec.header.type = PERF_RECORD_ITRACE_START;
7685 rec.header.misc = 0;
7686 rec.header.size = sizeof(rec);
7687 rec.pid = perf_event_pid(event, current);
7688 rec.tid = perf_event_tid(event, current);
7690 perf_event_header__init_id(&rec.header, &sample, event);
7691 ret = perf_output_begin(&handle, event, rec.header.size);
7696 perf_output_put(&handle, rec);
7697 perf_event__output_id_sample(event, &handle, &sample);
7699 perf_output_end(&handle);
7703 __perf_event_account_interrupt(struct perf_event *event, int throttle)
7705 struct hw_perf_event *hwc = &event->hw;
7709 seq = __this_cpu_read(perf_throttled_seq);
7710 if (seq != hwc->interrupts_seq) {
7711 hwc->interrupts_seq = seq;
7712 hwc->interrupts = 1;
7715 if (unlikely(throttle
7716 && hwc->interrupts >= max_samples_per_tick)) {
7717 __this_cpu_inc(perf_throttled_count);
7718 tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
7719 hwc->interrupts = MAX_INTERRUPTS;
7720 perf_log_throttle(event, 0);
7725 if (event->attr.freq) {
7726 u64 now = perf_clock();
7727 s64 delta = now - hwc->freq_time_stamp;
7729 hwc->freq_time_stamp = now;
7731 if (delta > 0 && delta < 2*TICK_NSEC)
7732 perf_adjust_period(event, delta, hwc->last_period, true);
7738 int perf_event_account_interrupt(struct perf_event *event)
7740 return __perf_event_account_interrupt(event, 1);
7744 * Generic event overflow handling, sampling.
7747 static int __perf_event_overflow(struct perf_event *event,
7748 int throttle, struct perf_sample_data *data,
7749 struct pt_regs *regs)
7751 int events = atomic_read(&event->event_limit);
7755 * Non-sampling counters might still use the PMI to fold short
7756 * hardware counters, ignore those.
7758 if (unlikely(!is_sampling_event(event)))
7761 ret = __perf_event_account_interrupt(event, throttle);
7764 * XXX event_limit might not quite work as expected on inherited
7768 event->pending_kill = POLL_IN;
7769 if (events && atomic_dec_and_test(&event->event_limit)) {
7771 event->pending_kill = POLL_HUP;
7773 perf_event_disable_inatomic(event);
7776 READ_ONCE(event->overflow_handler)(event, data, regs);
7778 if (*perf_event_fasync(event) && event->pending_kill) {
7779 event->pending_wakeup = 1;
7780 irq_work_queue(&event->pending);
7786 int perf_event_overflow(struct perf_event *event,
7787 struct perf_sample_data *data,
7788 struct pt_regs *regs)
7790 return __perf_event_overflow(event, 1, data, regs);
7794 * Generic software event infrastructure
7797 struct swevent_htable {
7798 struct swevent_hlist *swevent_hlist;
7799 struct mutex hlist_mutex;
7802 /* Recursion avoidance in each contexts */
7803 int recursion[PERF_NR_CONTEXTS];
7806 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
7809 * We directly increment event->count and keep a second value in
7810 * event->hw.period_left to count intervals. This period event
7811 * is kept in the range [-sample_period, 0] so that we can use the
7815 u64 perf_swevent_set_period(struct perf_event *event)
7817 struct hw_perf_event *hwc = &event->hw;
7818 u64 period = hwc->last_period;
7822 hwc->last_period = hwc->sample_period;
7825 old = val = local64_read(&hwc->period_left);
7829 nr = div64_u64(period + val, period);
7830 offset = nr * period;
7832 if (local64_cmpxchg(&hwc->period_left, old, val) != old)
7838 static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
7839 struct perf_sample_data *data,
7840 struct pt_regs *regs)
7842 struct hw_perf_event *hwc = &event->hw;
7846 overflow = perf_swevent_set_period(event);
7848 if (hwc->interrupts == MAX_INTERRUPTS)
7851 for (; overflow; overflow--) {
7852 if (__perf_event_overflow(event, throttle,
7855 * We inhibit the overflow from happening when
7856 * hwc->interrupts == MAX_INTERRUPTS.
7864 static void perf_swevent_event(struct perf_event *event, u64 nr,
7865 struct perf_sample_data *data,
7866 struct pt_regs *regs)
7868 struct hw_perf_event *hwc = &event->hw;
7870 local64_add(nr, &event->count);
7875 if (!is_sampling_event(event))
7878 if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
7880 return perf_swevent_overflow(event, 1, data, regs);
7882 data->period = event->hw.last_period;
7884 if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
7885 return perf_swevent_overflow(event, 1, data, regs);
7887 if (local64_add_negative(nr, &hwc->period_left))
7890 perf_swevent_overflow(event, 0, data, regs);
7893 static int perf_exclude_event(struct perf_event *event,
7894 struct pt_regs *regs)
7896 if (event->hw.state & PERF_HES_STOPPED)
7900 if (event->attr.exclude_user && user_mode(regs))
7903 if (event->attr.exclude_kernel && !user_mode(regs))
7910 static int perf_swevent_match(struct perf_event *event,
7911 enum perf_type_id type,
7913 struct perf_sample_data *data,
7914 struct pt_regs *regs)
7916 if (event->attr.type != type)
7919 if (event->attr.config != event_id)
7922 if (perf_exclude_event(event, regs))
7928 static inline u64 swevent_hash(u64 type, u32 event_id)
7930 u64 val = event_id | (type << 32);
7932 return hash_64(val, SWEVENT_HLIST_BITS);
7935 static inline struct hlist_head *
7936 __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
7938 u64 hash = swevent_hash(type, event_id);
7940 return &hlist->heads[hash];
7943 /* For the read side: events when they trigger */
7944 static inline struct hlist_head *
7945 find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
7947 struct swevent_hlist *hlist;
7949 hlist = rcu_dereference(swhash->swevent_hlist);
7953 return __find_swevent_head(hlist, type, event_id);
7956 /* For the event head insertion and removal in the hlist */
7957 static inline struct hlist_head *
7958 find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
7960 struct swevent_hlist *hlist;
7961 u32 event_id = event->attr.config;
7962 u64 type = event->attr.type;
7965 * Event scheduling is always serialized against hlist allocation
7966 * and release. Which makes the protected version suitable here.
7967 * The context lock guarantees that.
7969 hlist = rcu_dereference_protected(swhash->swevent_hlist,
7970 lockdep_is_held(&event->ctx->lock));
7974 return __find_swevent_head(hlist, type, event_id);
7977 static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
7979 struct perf_sample_data *data,
7980 struct pt_regs *regs)
7982 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
7983 struct perf_event *event;
7984 struct hlist_head *head;
7987 head = find_swevent_head_rcu(swhash, type, event_id);
7991 hlist_for_each_entry_rcu(event, head, hlist_entry) {
7992 if (perf_swevent_match(event, type, event_id, data, regs))
7993 perf_swevent_event(event, nr, data, regs);
7999 DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
8001 int perf_swevent_get_recursion_context(void)
8003 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8005 return get_recursion_context(swhash->recursion);
8007 EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
8009 void perf_swevent_put_recursion_context(int rctx)
8011 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8013 put_recursion_context(swhash->recursion, rctx);
8016 void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8018 struct perf_sample_data data;
8020 if (WARN_ON_ONCE(!regs))
8023 perf_sample_data_init(&data, addr, 0);
8024 do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
8027 void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
8031 preempt_disable_notrace();
8032 rctx = perf_swevent_get_recursion_context();
8033 if (unlikely(rctx < 0))
8036 ___perf_sw_event(event_id, nr, regs, addr);
8038 perf_swevent_put_recursion_context(rctx);
8040 preempt_enable_notrace();
8043 static void perf_swevent_read(struct perf_event *event)
8047 static int perf_swevent_add(struct perf_event *event, int flags)
8049 struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
8050 struct hw_perf_event *hwc = &event->hw;
8051 struct hlist_head *head;
8053 if (is_sampling_event(event)) {
8054 hwc->last_period = hwc->sample_period;
8055 perf_swevent_set_period(event);
8058 hwc->state = !(flags & PERF_EF_START);
8060 head = find_swevent_head(swhash, event);
8061 if (WARN_ON_ONCE(!head))
8064 hlist_add_head_rcu(&event->hlist_entry, head);
8065 perf_event_update_userpage(event);
8070 static void perf_swevent_del(struct perf_event *event, int flags)
8072 hlist_del_rcu(&event->hlist_entry);
8075 static void perf_swevent_start(struct perf_event *event, int flags)
8077 event->hw.state = 0;
8080 static void perf_swevent_stop(struct perf_event *event, int flags)
8082 event->hw.state = PERF_HES_STOPPED;
8085 /* Deref the hlist from the update side */
8086 static inline struct swevent_hlist *
8087 swevent_hlist_deref(struct swevent_htable *swhash)
8089 return rcu_dereference_protected(swhash->swevent_hlist,
8090 lockdep_is_held(&swhash->hlist_mutex));
8093 static void swevent_hlist_release(struct swevent_htable *swhash)
8095 struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
8100 RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
8101 kfree_rcu(hlist, rcu_head);
8104 static void swevent_hlist_put_cpu(int cpu)
8106 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8108 mutex_lock(&swhash->hlist_mutex);
8110 if (!--swhash->hlist_refcount)
8111 swevent_hlist_release(swhash);
8113 mutex_unlock(&swhash->hlist_mutex);
8116 static void swevent_hlist_put(void)
8120 for_each_possible_cpu(cpu)
8121 swevent_hlist_put_cpu(cpu);
8124 static int swevent_hlist_get_cpu(int cpu)
8126 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
8129 mutex_lock(&swhash->hlist_mutex);
8130 if (!swevent_hlist_deref(swhash) &&
8131 cpumask_test_cpu(cpu, perf_online_mask)) {
8132 struct swevent_hlist *hlist;
8134 hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
8139 rcu_assign_pointer(swhash->swevent_hlist, hlist);
8141 swhash->hlist_refcount++;
8143 mutex_unlock(&swhash->hlist_mutex);
8148 static int swevent_hlist_get(void)
8150 int err, cpu, failed_cpu;
8152 mutex_lock(&pmus_lock);
8153 for_each_possible_cpu(cpu) {
8154 err = swevent_hlist_get_cpu(cpu);
8160 mutex_unlock(&pmus_lock);
8163 for_each_possible_cpu(cpu) {
8164 if (cpu == failed_cpu)
8166 swevent_hlist_put_cpu(cpu);
8168 mutex_unlock(&pmus_lock);
8172 struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
8174 static void sw_perf_event_destroy(struct perf_event *event)
8176 u64 event_id = event->attr.config;
8178 WARN_ON(event->parent);
8180 static_key_slow_dec(&perf_swevent_enabled[event_id]);
8181 swevent_hlist_put();
8184 static int perf_swevent_init(struct perf_event *event)
8186 u64 event_id = event->attr.config;
8188 if (event->attr.type != PERF_TYPE_SOFTWARE)
8192 * no branch sampling for software events
8194 if (has_branch_stack(event))
8198 case PERF_COUNT_SW_CPU_CLOCK:
8199 case PERF_COUNT_SW_TASK_CLOCK:
8206 if (event_id >= PERF_COUNT_SW_MAX)
8209 if (!event->parent) {
8212 err = swevent_hlist_get();
8216 static_key_slow_inc(&perf_swevent_enabled[event_id]);
8217 event->destroy = sw_perf_event_destroy;
8223 static struct pmu perf_swevent = {
8224 .task_ctx_nr = perf_sw_context,
8226 .capabilities = PERF_PMU_CAP_NO_NMI,
8228 .event_init = perf_swevent_init,
8229 .add = perf_swevent_add,
8230 .del = perf_swevent_del,
8231 .start = perf_swevent_start,
8232 .stop = perf_swevent_stop,
8233 .read = perf_swevent_read,
8236 #ifdef CONFIG_EVENT_TRACING
8238 static int perf_tp_filter_match(struct perf_event *event,
8239 struct perf_sample_data *data)
8241 void *record = data->raw->frag.data;
8243 /* only top level events have filters set */
8245 event = event->parent;
8247 if (likely(!event->filter) || filter_match_preds(event->filter, record))
8252 static int perf_tp_event_match(struct perf_event *event,
8253 struct perf_sample_data *data,
8254 struct pt_regs *regs)
8256 if (event->hw.state & PERF_HES_STOPPED)
8259 * All tracepoints are from kernel-space.
8261 if (event->attr.exclude_kernel)
8264 if (!perf_tp_filter_match(event, data))
8270 void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
8271 struct trace_event_call *call, u64 count,
8272 struct pt_regs *regs, struct hlist_head *head,
8273 struct task_struct *task)
8275 if (bpf_prog_array_valid(call)) {
8276 *(struct pt_regs **)raw_data = regs;
8277 if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
8278 perf_swevent_put_recursion_context(rctx);
8282 perf_tp_event(call->event.type, count, raw_data, size, regs, head,
8285 EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
8287 void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
8288 struct pt_regs *regs, struct hlist_head *head, int rctx,
8289 struct task_struct *task)
8291 struct perf_sample_data data;
8292 struct perf_event *event;
8294 struct perf_raw_record raw = {
8301 perf_sample_data_init(&data, 0, 0);
8304 perf_trace_buf_update(record, event_type);
8306 hlist_for_each_entry_rcu(event, head, hlist_entry) {
8307 if (perf_tp_event_match(event, &data, regs))
8308 perf_swevent_event(event, count, &data, regs);
8312 * If we got specified a target task, also iterate its context and
8313 * deliver this event there too.
8315 if (task && task != current) {
8316 struct perf_event_context *ctx;
8317 struct trace_entry *entry = record;
8320 ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
8324 list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
8325 if (event->cpu != smp_processor_id())
8327 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8329 if (event->attr.config != entry->type)
8331 if (perf_tp_event_match(event, &data, regs))
8332 perf_swevent_event(event, count, &data, regs);
8338 perf_swevent_put_recursion_context(rctx);
8340 EXPORT_SYMBOL_GPL(perf_tp_event);
8342 static void tp_perf_event_destroy(struct perf_event *event)
8344 perf_trace_destroy(event);
8347 static int perf_tp_event_init(struct perf_event *event)
8351 if (event->attr.type != PERF_TYPE_TRACEPOINT)
8355 * no branch sampling for tracepoint events
8357 if (has_branch_stack(event))
8360 err = perf_trace_init(event);
8364 event->destroy = tp_perf_event_destroy;
8369 static struct pmu perf_tracepoint = {
8370 .task_ctx_nr = perf_sw_context,
8372 .event_init = perf_tp_event_init,
8373 .add = perf_trace_add,
8374 .del = perf_trace_del,
8375 .start = perf_swevent_start,
8376 .stop = perf_swevent_stop,
8377 .read = perf_swevent_read,
8380 #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
8382 * Flags in config, used by dynamic PMU kprobe and uprobe
8383 * The flags should match following PMU_FORMAT_ATTR().
8385 * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
8386 * if not set, create kprobe/uprobe
8388 * The following values specify a reference counter (or semaphore in the
8389 * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
8390 * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
8392 * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
8393 * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
8395 enum perf_probe_config {
8396 PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
8397 PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
8398 PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
8401 PMU_FORMAT_ATTR(retprobe, "config:0");
8404 #ifdef CONFIG_KPROBE_EVENTS
8405 static struct attribute *kprobe_attrs[] = {
8406 &format_attr_retprobe.attr,
8410 static struct attribute_group kprobe_format_group = {
8412 .attrs = kprobe_attrs,
8415 static const struct attribute_group *kprobe_attr_groups[] = {
8416 &kprobe_format_group,
8420 static int perf_kprobe_event_init(struct perf_event *event);
8421 static struct pmu perf_kprobe = {
8422 .task_ctx_nr = perf_sw_context,
8423 .event_init = perf_kprobe_event_init,
8424 .add = perf_trace_add,
8425 .del = perf_trace_del,
8426 .start = perf_swevent_start,
8427 .stop = perf_swevent_stop,
8428 .read = perf_swevent_read,
8429 .attr_groups = kprobe_attr_groups,
8432 static int perf_kprobe_event_init(struct perf_event *event)
8437 if (event->attr.type != perf_kprobe.type)
8440 if (!capable(CAP_SYS_ADMIN))
8444 * no branch sampling for probe events
8446 if (has_branch_stack(event))
8449 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8450 err = perf_kprobe_init(event, is_retprobe);
8454 event->destroy = perf_kprobe_destroy;
8458 #endif /* CONFIG_KPROBE_EVENTS */
8460 #ifdef CONFIG_UPROBE_EVENTS
8461 PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
8463 static struct attribute *uprobe_attrs[] = {
8464 &format_attr_retprobe.attr,
8465 &format_attr_ref_ctr_offset.attr,
8469 static struct attribute_group uprobe_format_group = {
8471 .attrs = uprobe_attrs,
8474 static const struct attribute_group *uprobe_attr_groups[] = {
8475 &uprobe_format_group,
8479 static int perf_uprobe_event_init(struct perf_event *event);
8480 static struct pmu perf_uprobe = {
8481 .task_ctx_nr = perf_sw_context,
8482 .event_init = perf_uprobe_event_init,
8483 .add = perf_trace_add,
8484 .del = perf_trace_del,
8485 .start = perf_swevent_start,
8486 .stop = perf_swevent_stop,
8487 .read = perf_swevent_read,
8488 .attr_groups = uprobe_attr_groups,
8491 static int perf_uprobe_event_init(struct perf_event *event)
8494 unsigned long ref_ctr_offset;
8497 if (event->attr.type != perf_uprobe.type)
8500 if (!capable(CAP_SYS_ADMIN))
8504 * no branch sampling for probe events
8506 if (has_branch_stack(event))
8509 is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
8510 ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
8511 err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
8515 event->destroy = perf_uprobe_destroy;
8519 #endif /* CONFIG_UPROBE_EVENTS */
8521 static inline void perf_tp_register(void)
8523 perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
8524 #ifdef CONFIG_KPROBE_EVENTS
8525 perf_pmu_register(&perf_kprobe, "kprobe", -1);
8527 #ifdef CONFIG_UPROBE_EVENTS
8528 perf_pmu_register(&perf_uprobe, "uprobe", -1);
8532 static void perf_event_free_filter(struct perf_event *event)
8534 ftrace_profile_free_filter(event);
8537 #ifdef CONFIG_BPF_SYSCALL
8538 static void bpf_overflow_handler(struct perf_event *event,
8539 struct perf_sample_data *data,
8540 struct pt_regs *regs)
8542 struct bpf_perf_event_data_kern ctx = {
8548 ctx.regs = perf_arch_bpf_user_pt_regs(regs);
8550 if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
8553 ret = BPF_PROG_RUN(event->prog, &ctx);
8556 __this_cpu_dec(bpf_prog_active);
8561 event->orig_overflow_handler(event, data, regs);
8564 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8566 struct bpf_prog *prog;
8568 if (event->overflow_handler_context)
8569 /* hw breakpoint or kernel counter */
8575 prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
8577 return PTR_ERR(prog);
8580 event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
8581 WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
8585 static void perf_event_free_bpf_handler(struct perf_event *event)
8587 struct bpf_prog *prog = event->prog;
8592 WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
8597 static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
8601 static void perf_event_free_bpf_handler(struct perf_event *event)
8607 * returns true if the event is a tracepoint, or a kprobe/upprobe created
8608 * with perf_event_open()
8610 static inline bool perf_event_is_tracing(struct perf_event *event)
8612 if (event->pmu == &perf_tracepoint)
8614 #ifdef CONFIG_KPROBE_EVENTS
8615 if (event->pmu == &perf_kprobe)
8618 #ifdef CONFIG_UPROBE_EVENTS
8619 if (event->pmu == &perf_uprobe)
8625 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8627 bool is_kprobe, is_tracepoint, is_syscall_tp;
8628 struct bpf_prog *prog;
8631 if (!perf_event_is_tracing(event))
8632 return perf_event_set_bpf_handler(event, prog_fd);
8634 is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
8635 is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
8636 is_syscall_tp = is_syscall_trace_event(event->tp_event);
8637 if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
8638 /* bpf programs can only be attached to u/kprobe or tracepoint */
8641 prog = bpf_prog_get(prog_fd);
8643 return PTR_ERR(prog);
8645 if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
8646 (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
8647 (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
8648 /* valid fd, but invalid bpf program type */
8653 /* Kprobe override only works for kprobes, not uprobes. */
8654 if (prog->kprobe_override &&
8655 !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
8660 if (is_tracepoint || is_syscall_tp) {
8661 int off = trace_event_get_offsets(event->tp_event);
8663 if (prog->aux->max_ctx_offset > off) {
8669 ret = perf_event_attach_bpf_prog(event, prog);
8675 static void perf_event_free_bpf_prog(struct perf_event *event)
8677 if (!perf_event_is_tracing(event)) {
8678 perf_event_free_bpf_handler(event);
8681 perf_event_detach_bpf_prog(event);
8686 static inline void perf_tp_register(void)
8690 static void perf_event_free_filter(struct perf_event *event)
8694 static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
8699 static void perf_event_free_bpf_prog(struct perf_event *event)
8702 #endif /* CONFIG_EVENT_TRACING */
8704 #ifdef CONFIG_HAVE_HW_BREAKPOINT
8705 void perf_bp_event(struct perf_event *bp, void *data)
8707 struct perf_sample_data sample;
8708 struct pt_regs *regs = data;
8710 perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
8712 if (!bp->hw.state && !perf_exclude_event(bp, regs))
8713 perf_swevent_event(bp, 1, &sample, regs);
8718 * Allocate a new address filter
8720 static struct perf_addr_filter *
8721 perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
8723 int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
8724 struct perf_addr_filter *filter;
8726 filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
8730 INIT_LIST_HEAD(&filter->entry);
8731 list_add_tail(&filter->entry, filters);
8736 static void free_filters_list(struct list_head *filters)
8738 struct perf_addr_filter *filter, *iter;
8740 list_for_each_entry_safe(filter, iter, filters, entry) {
8741 path_put(&filter->path);
8742 list_del(&filter->entry);
8748 * Free existing address filters and optionally install new ones
8750 static void perf_addr_filters_splice(struct perf_event *event,
8751 struct list_head *head)
8753 unsigned long flags;
8756 if (!has_addr_filter(event))
8759 /* don't bother with children, they don't have their own filters */
8763 raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
8765 list_splice_init(&event->addr_filters.list, &list);
8767 list_splice(head, &event->addr_filters.list);
8769 raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
8771 free_filters_list(&list);
8775 * Scan through mm's vmas and see if one of them matches the
8776 * @filter; if so, adjust filter's address range.
8777 * Called with mm::mmap_sem down for reading.
8779 static unsigned long perf_addr_filter_apply(struct perf_addr_filter *filter,
8780 struct mm_struct *mm)
8782 struct vm_area_struct *vma;
8784 for (vma = mm->mmap; vma; vma = vma->vm_next) {
8785 struct file *file = vma->vm_file;
8786 unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8787 unsigned long vma_size = vma->vm_end - vma->vm_start;
8792 if (!perf_addr_filter_match(filter, file, off, vma_size))
8795 return vma->vm_start;
8802 * Update event's address range filters based on the
8803 * task's existing mappings, if any.
8805 static void perf_event_addr_filters_apply(struct perf_event *event)
8807 struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8808 struct task_struct *task = READ_ONCE(event->ctx->task);
8809 struct perf_addr_filter *filter;
8810 struct mm_struct *mm = NULL;
8811 unsigned int count = 0;
8812 unsigned long flags;
8815 * We may observe TASK_TOMBSTONE, which means that the event tear-down
8816 * will stop on the parent's child_mutex that our caller is also holding
8818 if (task == TASK_TOMBSTONE)
8821 if (!ifh->nr_file_filters)
8824 mm = get_task_mm(event->ctx->task);
8828 down_read(&mm->mmap_sem);
8830 raw_spin_lock_irqsave(&ifh->lock, flags);
8831 list_for_each_entry(filter, &ifh->list, entry) {
8832 event->addr_filters_offs[count] = 0;
8835 * Adjust base offset if the filter is associated to a binary
8836 * that needs to be mapped:
8838 if (filter->path.dentry)
8839 event->addr_filters_offs[count] =
8840 perf_addr_filter_apply(filter, mm);
8845 event->addr_filters_gen++;
8846 raw_spin_unlock_irqrestore(&ifh->lock, flags);
8848 up_read(&mm->mmap_sem);
8853 perf_event_stop(event, 1);
8857 * Address range filtering: limiting the data to certain
8858 * instruction address ranges. Filters are ioctl()ed to us from
8859 * userspace as ascii strings.
8861 * Filter string format:
8864 * where ACTION is one of the
8865 * * "filter": limit the trace to this region
8866 * * "start": start tracing from this address
8867 * * "stop": stop tracing at this address/region;
8869 * * for kernel addresses: <start address>[/<size>]
8870 * * for object files: <start address>[/<size>]@</path/to/object/file>
8872 * if <size> is not specified or is zero, the range is treated as a single
8873 * address; not valid for ACTION=="filter".
8887 IF_STATE_ACTION = 0,
8892 static const match_table_t if_tokens = {
8893 { IF_ACT_FILTER, "filter" },
8894 { IF_ACT_START, "start" },
8895 { IF_ACT_STOP, "stop" },
8896 { IF_SRC_FILE, "%u/%u@%s" },
8897 { IF_SRC_KERNEL, "%u/%u" },
8898 { IF_SRC_FILEADDR, "%u@%s" },
8899 { IF_SRC_KERNELADDR, "%u" },
8900 { IF_ACT_NONE, NULL },
8904 * Address filter string parser
8907 perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
8908 struct list_head *filters)
8910 struct perf_addr_filter *filter = NULL;
8911 char *start, *orig, *filename = NULL;
8912 substring_t args[MAX_OPT_ARGS];
8913 int state = IF_STATE_ACTION, token;
8914 unsigned int kernel = 0;
8917 orig = fstr = kstrdup(fstr, GFP_KERNEL);
8921 while ((start = strsep(&fstr, " ,\n")) != NULL) {
8922 static const enum perf_addr_filter_action_t actions[] = {
8923 [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
8924 [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
8925 [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
8932 /* filter definition begins */
8933 if (state == IF_STATE_ACTION) {
8934 filter = perf_addr_filter_new(event, filters);
8939 token = match_token(start, if_tokens, args);
8944 if (state != IF_STATE_ACTION)
8947 filter->action = actions[token];
8948 state = IF_STATE_SOURCE;
8951 case IF_SRC_KERNELADDR:
8955 case IF_SRC_FILEADDR:
8957 if (state != IF_STATE_SOURCE)
8961 ret = kstrtoul(args[0].from, 0, &filter->offset);
8965 if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
8967 ret = kstrtoul(args[1].from, 0, &filter->size);
8972 if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
8973 int fpos = token == IF_SRC_FILE ? 2 : 1;
8975 filename = match_strdup(&args[fpos]);
8982 state = IF_STATE_END;
8990 * Filter definition is fully parsed, validate and install it.
8991 * Make sure that it doesn't contradict itself or the event's
8994 if (state == IF_STATE_END) {
8996 if (kernel && event->attr.exclude_kernel)
9000 * ACTION "filter" must have a non-zero length region
9003 if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
9012 * For now, we only support file-based filters
9013 * in per-task events; doing so for CPU-wide
9014 * events requires additional context switching
9015 * trickery, since same object code will be
9016 * mapped at different virtual addresses in
9017 * different processes.
9020 if (!event->ctx->task)
9021 goto fail_free_name;
9023 /* look up the path and grab its inode */
9024 ret = kern_path(filename, LOOKUP_FOLLOW,
9027 goto fail_free_name;
9033 if (!filter->path.dentry ||
9034 !S_ISREG(d_inode(filter->path.dentry)
9038 event->addr_filters.nr_file_filters++;
9041 /* ready to consume more filters */
9042 state = IF_STATE_ACTION;
9047 if (state != IF_STATE_ACTION)
9057 free_filters_list(filters);
9064 perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
9070 * Since this is called in perf_ioctl() path, we're already holding
9073 lockdep_assert_held(&event->ctx->mutex);
9075 if (WARN_ON_ONCE(event->parent))
9078 ret = perf_event_parse_addr_filter(event, filter_str, &filters);
9080 goto fail_clear_files;
9082 ret = event->pmu->addr_filters_validate(&filters);
9084 goto fail_free_filters;
9086 /* remove existing filters, if any */
9087 perf_addr_filters_splice(event, &filters);
9089 /* install new filters */
9090 perf_event_for_each_child(event, perf_event_addr_filters_apply);
9095 free_filters_list(&filters);
9098 event->addr_filters.nr_file_filters = 0;
9103 static int perf_event_set_filter(struct perf_event *event, void __user *arg)
9108 filter_str = strndup_user(arg, PAGE_SIZE);
9109 if (IS_ERR(filter_str))
9110 return PTR_ERR(filter_str);
9112 #ifdef CONFIG_EVENT_TRACING
9113 if (perf_event_is_tracing(event)) {
9114 struct perf_event_context *ctx = event->ctx;
9117 * Beware, here be dragons!!
9119 * the tracepoint muck will deadlock against ctx->mutex, but
9120 * the tracepoint stuff does not actually need it. So
9121 * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
9122 * already have a reference on ctx.
9124 * This can result in event getting moved to a different ctx,
9125 * but that does not affect the tracepoint state.
9127 mutex_unlock(&ctx->mutex);
9128 ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
9129 mutex_lock(&ctx->mutex);
9132 if (has_addr_filter(event))
9133 ret = perf_event_set_addr_filter(event, filter_str);
9140 * hrtimer based swevent callback
9143 static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
9145 enum hrtimer_restart ret = HRTIMER_RESTART;
9146 struct perf_sample_data data;
9147 struct pt_regs *regs;
9148 struct perf_event *event;
9151 event = container_of(hrtimer, struct perf_event, hw.hrtimer);
9153 if (event->state != PERF_EVENT_STATE_ACTIVE)
9154 return HRTIMER_NORESTART;
9156 event->pmu->read(event);
9158 perf_sample_data_init(&data, 0, event->hw.last_period);
9159 regs = get_irq_regs();
9161 if (regs && !perf_exclude_event(event, regs)) {
9162 if (!(event->attr.exclude_idle && is_idle_task(current)))
9163 if (__perf_event_overflow(event, 1, &data, regs))
9164 ret = HRTIMER_NORESTART;
9167 period = max_t(u64, 10000, event->hw.sample_period);
9168 hrtimer_forward_now(hrtimer, ns_to_ktime(period));
9173 static void perf_swevent_start_hrtimer(struct perf_event *event)
9175 struct hw_perf_event *hwc = &event->hw;
9178 if (!is_sampling_event(event))
9181 period = local64_read(&hwc->period_left);
9186 local64_set(&hwc->period_left, 0);
9188 period = max_t(u64, 10000, hwc->sample_period);
9190 hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
9191 HRTIMER_MODE_REL_PINNED);
9194 static void perf_swevent_cancel_hrtimer(struct perf_event *event)
9196 struct hw_perf_event *hwc = &event->hw;
9198 if (is_sampling_event(event)) {
9199 ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
9200 local64_set(&hwc->period_left, ktime_to_ns(remaining));
9202 hrtimer_cancel(&hwc->hrtimer);
9206 static void perf_swevent_init_hrtimer(struct perf_event *event)
9208 struct hw_perf_event *hwc = &event->hw;
9210 if (!is_sampling_event(event))
9213 hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
9214 hwc->hrtimer.function = perf_swevent_hrtimer;
9217 * Since hrtimers have a fixed rate, we can do a static freq->period
9218 * mapping and avoid the whole period adjust feedback stuff.
9220 if (event->attr.freq) {
9221 long freq = event->attr.sample_freq;
9223 event->attr.sample_period = NSEC_PER_SEC / freq;
9224 hwc->sample_period = event->attr.sample_period;
9225 local64_set(&hwc->period_left, hwc->sample_period);
9226 hwc->last_period = hwc->sample_period;
9227 event->attr.freq = 0;
9232 * Software event: cpu wall time clock
9235 static void cpu_clock_event_update(struct perf_event *event)
9240 now = local_clock();
9241 prev = local64_xchg(&event->hw.prev_count, now);
9242 local64_add(now - prev, &event->count);
9245 static void cpu_clock_event_start(struct perf_event *event, int flags)
9247 local64_set(&event->hw.prev_count, local_clock());
9248 perf_swevent_start_hrtimer(event);
9251 static void cpu_clock_event_stop(struct perf_event *event, int flags)
9253 perf_swevent_cancel_hrtimer(event);
9254 cpu_clock_event_update(event);
9257 static int cpu_clock_event_add(struct perf_event *event, int flags)
9259 if (flags & PERF_EF_START)
9260 cpu_clock_event_start(event, flags);
9261 perf_event_update_userpage(event);
9266 static void cpu_clock_event_del(struct perf_event *event, int flags)
9268 cpu_clock_event_stop(event, flags);
9271 static void cpu_clock_event_read(struct perf_event *event)
9273 cpu_clock_event_update(event);
9276 static int cpu_clock_event_init(struct perf_event *event)
9278 if (event->attr.type != PERF_TYPE_SOFTWARE)
9281 if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
9285 * no branch sampling for software events
9287 if (has_branch_stack(event))
9290 perf_swevent_init_hrtimer(event);
9295 static struct pmu perf_cpu_clock = {
9296 .task_ctx_nr = perf_sw_context,
9298 .capabilities = PERF_PMU_CAP_NO_NMI,
9300 .event_init = cpu_clock_event_init,
9301 .add = cpu_clock_event_add,
9302 .del = cpu_clock_event_del,
9303 .start = cpu_clock_event_start,
9304 .stop = cpu_clock_event_stop,
9305 .read = cpu_clock_event_read,
9309 * Software event: task time clock
9312 static void task_clock_event_update(struct perf_event *event, u64 now)
9317 prev = local64_xchg(&event->hw.prev_count, now);
9319 local64_add(delta, &event->count);
9322 static void task_clock_event_start(struct perf_event *event, int flags)
9324 local64_set(&event->hw.prev_count, event->ctx->time);
9325 perf_swevent_start_hrtimer(event);
9328 static void task_clock_event_stop(struct perf_event *event, int flags)
9330 perf_swevent_cancel_hrtimer(event);
9331 task_clock_event_update(event, event->ctx->time);
9334 static int task_clock_event_add(struct perf_event *event, int flags)
9336 if (flags & PERF_EF_START)
9337 task_clock_event_start(event, flags);
9338 perf_event_update_userpage(event);
9343 static void task_clock_event_del(struct perf_event *event, int flags)
9345 task_clock_event_stop(event, PERF_EF_UPDATE);
9348 static void task_clock_event_read(struct perf_event *event)
9350 u64 now = perf_clock();
9351 u64 delta = now - event->ctx->timestamp;
9352 u64 time = event->ctx->time + delta;
9354 task_clock_event_update(event, time);
9357 static int task_clock_event_init(struct perf_event *event)
9359 if (event->attr.type != PERF_TYPE_SOFTWARE)
9362 if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
9366 * no branch sampling for software events
9368 if (has_branch_stack(event))
9371 perf_swevent_init_hrtimer(event);
9376 static struct pmu perf_task_clock = {
9377 .task_ctx_nr = perf_sw_context,
9379 .capabilities = PERF_PMU_CAP_NO_NMI,
9381 .event_init = task_clock_event_init,
9382 .add = task_clock_event_add,
9383 .del = task_clock_event_del,
9384 .start = task_clock_event_start,
9385 .stop = task_clock_event_stop,
9386 .read = task_clock_event_read,
9389 static void perf_pmu_nop_void(struct pmu *pmu)
9393 static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
9397 static int perf_pmu_nop_int(struct pmu *pmu)
9402 static int perf_event_nop_int(struct perf_event *event, u64 value)
9407 static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
9409 static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
9411 __this_cpu_write(nop_txn_flags, flags);
9413 if (flags & ~PERF_PMU_TXN_ADD)
9416 perf_pmu_disable(pmu);
9419 static int perf_pmu_commit_txn(struct pmu *pmu)
9421 unsigned int flags = __this_cpu_read(nop_txn_flags);
9423 __this_cpu_write(nop_txn_flags, 0);
9425 if (flags & ~PERF_PMU_TXN_ADD)
9428 perf_pmu_enable(pmu);
9432 static void perf_pmu_cancel_txn(struct pmu *pmu)
9434 unsigned int flags = __this_cpu_read(nop_txn_flags);
9436 __this_cpu_write(nop_txn_flags, 0);
9438 if (flags & ~PERF_PMU_TXN_ADD)
9441 perf_pmu_enable(pmu);
9444 static int perf_event_idx_default(struct perf_event *event)
9450 * Ensures all contexts with the same task_ctx_nr have the same
9451 * pmu_cpu_context too.
9453 static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
9460 list_for_each_entry(pmu, &pmus, entry) {
9461 if (pmu->task_ctx_nr == ctxn)
9462 return pmu->pmu_cpu_context;
9468 static void free_pmu_context(struct pmu *pmu)
9471 * Static contexts such as perf_sw_context have a global lifetime
9472 * and may be shared between different PMUs. Avoid freeing them
9473 * when a single PMU is going away.
9475 if (pmu->task_ctx_nr > perf_invalid_context)
9478 free_percpu(pmu->pmu_cpu_context);
9482 * Let userspace know that this PMU supports address range filtering:
9484 static ssize_t nr_addr_filters_show(struct device *dev,
9485 struct device_attribute *attr,
9488 struct pmu *pmu = dev_get_drvdata(dev);
9490 return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
9492 DEVICE_ATTR_RO(nr_addr_filters);
9494 static struct idr pmu_idr;
9497 type_show(struct device *dev, struct device_attribute *attr, char *page)
9499 struct pmu *pmu = dev_get_drvdata(dev);
9501 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
9503 static DEVICE_ATTR_RO(type);
9506 perf_event_mux_interval_ms_show(struct device *dev,
9507 struct device_attribute *attr,
9510 struct pmu *pmu = dev_get_drvdata(dev);
9512 return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
9515 static DEFINE_MUTEX(mux_interval_mutex);
9518 perf_event_mux_interval_ms_store(struct device *dev,
9519 struct device_attribute *attr,
9520 const char *buf, size_t count)
9522 struct pmu *pmu = dev_get_drvdata(dev);
9523 int timer, cpu, ret;
9525 ret = kstrtoint(buf, 0, &timer);
9532 /* same value, noting to do */
9533 if (timer == pmu->hrtimer_interval_ms)
9536 mutex_lock(&mux_interval_mutex);
9537 pmu->hrtimer_interval_ms = timer;
9539 /* update all cpuctx for this PMU */
9541 for_each_online_cpu(cpu) {
9542 struct perf_cpu_context *cpuctx;
9543 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9544 cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
9546 cpu_function_call(cpu,
9547 (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
9550 mutex_unlock(&mux_interval_mutex);
9554 static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
9556 static struct attribute *pmu_dev_attrs[] = {
9557 &dev_attr_type.attr,
9558 &dev_attr_perf_event_mux_interval_ms.attr,
9561 ATTRIBUTE_GROUPS(pmu_dev);
9563 static int pmu_bus_running;
9564 static struct bus_type pmu_bus = {
9565 .name = "event_source",
9566 .dev_groups = pmu_dev_groups,
9569 static void pmu_dev_release(struct device *dev)
9574 static int pmu_dev_alloc(struct pmu *pmu)
9578 pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
9582 pmu->dev->groups = pmu->attr_groups;
9583 device_initialize(pmu->dev);
9584 ret = dev_set_name(pmu->dev, "%s", pmu->name);
9588 dev_set_drvdata(pmu->dev, pmu);
9589 pmu->dev->bus = &pmu_bus;
9590 pmu->dev->release = pmu_dev_release;
9591 ret = device_add(pmu->dev);
9595 /* For PMUs with address filters, throw in an extra attribute: */
9596 if (pmu->nr_addr_filters)
9597 ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
9606 device_del(pmu->dev);
9609 put_device(pmu->dev);
9613 static struct lock_class_key cpuctx_mutex;
9614 static struct lock_class_key cpuctx_lock;
9616 int perf_pmu_register(struct pmu *pmu, const char *name, int type)
9620 mutex_lock(&pmus_lock);
9622 pmu->pmu_disable_count = alloc_percpu(int);
9623 if (!pmu->pmu_disable_count)
9632 type = idr_alloc(&pmu_idr, pmu, PERF_TYPE_MAX, 0, GFP_KERNEL);
9640 if (pmu_bus_running) {
9641 ret = pmu_dev_alloc(pmu);
9647 if (pmu->task_ctx_nr == perf_hw_context) {
9648 static int hw_context_taken = 0;
9651 * Other than systems with heterogeneous CPUs, it never makes
9652 * sense for two PMUs to share perf_hw_context. PMUs which are
9653 * uncore must use perf_invalid_context.
9655 if (WARN_ON_ONCE(hw_context_taken &&
9656 !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
9657 pmu->task_ctx_nr = perf_invalid_context;
9659 hw_context_taken = 1;
9662 pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
9663 if (pmu->pmu_cpu_context)
9664 goto got_cpu_context;
9667 pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
9668 if (!pmu->pmu_cpu_context)
9671 for_each_possible_cpu(cpu) {
9672 struct perf_cpu_context *cpuctx;
9674 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
9675 __perf_event_init_context(&cpuctx->ctx);
9676 lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
9677 lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
9678 cpuctx->ctx.pmu = pmu;
9679 cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
9681 __perf_mux_hrtimer_init(cpuctx, cpu);
9685 if (!pmu->start_txn) {
9686 if (pmu->pmu_enable) {
9688 * If we have pmu_enable/pmu_disable calls, install
9689 * transaction stubs that use that to try and batch
9690 * hardware accesses.
9692 pmu->start_txn = perf_pmu_start_txn;
9693 pmu->commit_txn = perf_pmu_commit_txn;
9694 pmu->cancel_txn = perf_pmu_cancel_txn;
9696 pmu->start_txn = perf_pmu_nop_txn;
9697 pmu->commit_txn = perf_pmu_nop_int;
9698 pmu->cancel_txn = perf_pmu_nop_void;
9702 if (!pmu->pmu_enable) {
9703 pmu->pmu_enable = perf_pmu_nop_void;
9704 pmu->pmu_disable = perf_pmu_nop_void;
9707 if (!pmu->check_period)
9708 pmu->check_period = perf_event_nop_int;
9710 if (!pmu->event_idx)
9711 pmu->event_idx = perf_event_idx_default;
9713 list_add_rcu(&pmu->entry, &pmus);
9714 atomic_set(&pmu->exclusive_cnt, 0);
9717 mutex_unlock(&pmus_lock);
9722 device_del(pmu->dev);
9723 put_device(pmu->dev);
9726 if (pmu->type >= PERF_TYPE_MAX)
9727 idr_remove(&pmu_idr, pmu->type);
9730 free_percpu(pmu->pmu_disable_count);
9733 EXPORT_SYMBOL_GPL(perf_pmu_register);
9735 void perf_pmu_unregister(struct pmu *pmu)
9737 mutex_lock(&pmus_lock);
9738 list_del_rcu(&pmu->entry);
9741 * We dereference the pmu list under both SRCU and regular RCU, so
9742 * synchronize against both of those.
9744 synchronize_srcu(&pmus_srcu);
9747 free_percpu(pmu->pmu_disable_count);
9748 if (pmu->type >= PERF_TYPE_MAX)
9749 idr_remove(&pmu_idr, pmu->type);
9750 if (pmu_bus_running) {
9751 if (pmu->nr_addr_filters)
9752 device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
9753 device_del(pmu->dev);
9754 put_device(pmu->dev);
9756 free_pmu_context(pmu);
9757 mutex_unlock(&pmus_lock);
9759 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
9761 static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
9763 struct perf_event_context *ctx = NULL;
9766 if (!try_module_get(pmu->module))
9770 * A number of pmu->event_init() methods iterate the sibling_list to,
9771 * for example, validate if the group fits on the PMU. Therefore,
9772 * if this is a sibling event, acquire the ctx->mutex to protect
9775 if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
9777 * This ctx->mutex can nest when we're called through
9778 * inheritance. See the perf_event_ctx_lock_nested() comment.
9780 ctx = perf_event_ctx_lock_nested(event->group_leader,
9781 SINGLE_DEPTH_NESTING);
9786 ret = pmu->event_init(event);
9789 perf_event_ctx_unlock(event->group_leader, ctx);
9792 module_put(pmu->module);
9797 static struct pmu *perf_init_event(struct perf_event *event)
9803 idx = srcu_read_lock(&pmus_srcu);
9805 /* Try parent's PMU first: */
9806 if (event->parent && event->parent->pmu) {
9807 pmu = event->parent->pmu;
9808 ret = perf_try_init_event(pmu, event);
9814 pmu = idr_find(&pmu_idr, event->attr.type);
9817 ret = perf_try_init_event(pmu, event);
9823 list_for_each_entry_rcu(pmu, &pmus, entry) {
9824 ret = perf_try_init_event(pmu, event);
9828 if (ret != -ENOENT) {
9833 pmu = ERR_PTR(-ENOENT);
9835 srcu_read_unlock(&pmus_srcu, idx);
9840 static void attach_sb_event(struct perf_event *event)
9842 struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
9844 raw_spin_lock(&pel->lock);
9845 list_add_rcu(&event->sb_list, &pel->list);
9846 raw_spin_unlock(&pel->lock);
9850 * We keep a list of all !task (and therefore per-cpu) events
9851 * that need to receive side-band records.
9853 * This avoids having to scan all the various PMU per-cpu contexts
9856 static void account_pmu_sb_event(struct perf_event *event)
9858 if (is_sb_event(event))
9859 attach_sb_event(event);
9862 static void account_event_cpu(struct perf_event *event, int cpu)
9867 if (is_cgroup_event(event))
9868 atomic_inc(&per_cpu(perf_cgroup_events, cpu));
9871 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
9872 static void account_freq_event_nohz(void)
9874 #ifdef CONFIG_NO_HZ_FULL
9875 /* Lock so we don't race with concurrent unaccount */
9876 spin_lock(&nr_freq_lock);
9877 if (atomic_inc_return(&nr_freq_events) == 1)
9878 tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
9879 spin_unlock(&nr_freq_lock);
9883 static void account_freq_event(void)
9885 if (tick_nohz_full_enabled())
9886 account_freq_event_nohz();
9888 atomic_inc(&nr_freq_events);
9892 static void account_event(struct perf_event *event)
9899 if (event->attach_state & PERF_ATTACH_TASK)
9901 if (event->attr.mmap || event->attr.mmap_data)
9902 atomic_inc(&nr_mmap_events);
9903 if (event->attr.comm)
9904 atomic_inc(&nr_comm_events);
9905 if (event->attr.namespaces)
9906 atomic_inc(&nr_namespaces_events);
9907 if (event->attr.task)
9908 atomic_inc(&nr_task_events);
9909 if (event->attr.freq)
9910 account_freq_event();
9911 if (event->attr.context_switch) {
9912 atomic_inc(&nr_switch_events);
9915 if (has_branch_stack(event))
9917 if (is_cgroup_event(event))
9922 * We need the mutex here because static_branch_enable()
9923 * must complete *before* the perf_sched_count increment
9926 if (atomic_inc_not_zero(&perf_sched_count))
9929 mutex_lock(&perf_sched_mutex);
9930 if (!atomic_read(&perf_sched_count)) {
9931 static_branch_enable(&perf_sched_events);
9933 * Guarantee that all CPUs observe they key change and
9934 * call the perf scheduling hooks before proceeding to
9935 * install events that need them.
9940 * Now that we have waited for the sync_sched(), allow further
9941 * increments to by-pass the mutex.
9943 atomic_inc(&perf_sched_count);
9944 mutex_unlock(&perf_sched_mutex);
9948 account_event_cpu(event, event->cpu);
9950 account_pmu_sb_event(event);
9954 * Allocate and initialize an event structure
9956 static struct perf_event *
9957 perf_event_alloc(struct perf_event_attr *attr, int cpu,
9958 struct task_struct *task,
9959 struct perf_event *group_leader,
9960 struct perf_event *parent_event,
9961 perf_overflow_handler_t overflow_handler,
9962 void *context, int cgroup_fd)
9965 struct perf_event *event;
9966 struct hw_perf_event *hwc;
9969 if ((unsigned)cpu >= nr_cpu_ids) {
9970 if (!task || cpu != -1)
9971 return ERR_PTR(-EINVAL);
9974 event = kzalloc(sizeof(*event), GFP_KERNEL);
9976 return ERR_PTR(-ENOMEM);
9979 * Single events are their own group leaders, with an
9980 * empty sibling list:
9983 group_leader = event;
9985 mutex_init(&event->child_mutex);
9986 INIT_LIST_HEAD(&event->child_list);
9988 INIT_LIST_HEAD(&event->event_entry);
9989 INIT_LIST_HEAD(&event->sibling_list);
9990 INIT_LIST_HEAD(&event->active_list);
9991 init_event_group(event);
9992 INIT_LIST_HEAD(&event->rb_entry);
9993 INIT_LIST_HEAD(&event->active_entry);
9994 INIT_LIST_HEAD(&event->addr_filters.list);
9995 INIT_HLIST_NODE(&event->hlist_entry);
9998 init_waitqueue_head(&event->waitq);
9999 init_irq_work(&event->pending, perf_pending_event);
10001 mutex_init(&event->mmap_mutex);
10002 raw_spin_lock_init(&event->addr_filters.lock);
10004 atomic_long_set(&event->refcount, 1);
10006 event->attr = *attr;
10007 event->group_leader = group_leader;
10011 event->parent = parent_event;
10013 event->ns = get_pid_ns(task_active_pid_ns(current));
10014 event->id = atomic64_inc_return(&perf_event_id);
10016 event->state = PERF_EVENT_STATE_INACTIVE;
10019 event->attach_state = PERF_ATTACH_TASK;
10021 * XXX pmu::event_init needs to know what task to account to
10022 * and we cannot use the ctx information because we need the
10023 * pmu before we get a ctx.
10025 get_task_struct(task);
10026 event->hw.target = task;
10029 event->clock = &local_clock;
10031 event->clock = parent_event->clock;
10033 if (!overflow_handler && parent_event) {
10034 overflow_handler = parent_event->overflow_handler;
10035 context = parent_event->overflow_handler_context;
10036 #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
10037 if (overflow_handler == bpf_overflow_handler) {
10038 struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
10040 if (IS_ERR(prog)) {
10041 err = PTR_ERR(prog);
10044 event->prog = prog;
10045 event->orig_overflow_handler =
10046 parent_event->orig_overflow_handler;
10051 if (overflow_handler) {
10052 event->overflow_handler = overflow_handler;
10053 event->overflow_handler_context = context;
10054 } else if (is_write_backward(event)){
10055 event->overflow_handler = perf_event_output_backward;
10056 event->overflow_handler_context = NULL;
10058 event->overflow_handler = perf_event_output_forward;
10059 event->overflow_handler_context = NULL;
10062 perf_event__state_init(event);
10067 hwc->sample_period = attr->sample_period;
10068 if (attr->freq && attr->sample_freq)
10069 hwc->sample_period = 1;
10070 hwc->last_period = hwc->sample_period;
10072 local64_set(&hwc->period_left, hwc->sample_period);
10075 * We currently do not support PERF_SAMPLE_READ on inherited events.
10076 * See perf_output_read().
10078 if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
10081 if (!has_branch_stack(event))
10082 event->attr.branch_sample_type = 0;
10084 if (cgroup_fd != -1) {
10085 err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
10090 pmu = perf_init_event(event);
10092 err = PTR_ERR(pmu);
10096 err = exclusive_event_init(event);
10100 if (has_addr_filter(event)) {
10101 event->addr_filters_offs = kcalloc(pmu->nr_addr_filters,
10102 sizeof(unsigned long),
10104 if (!event->addr_filters_offs) {
10109 /* force hw sync on the address filters */
10110 event->addr_filters_gen = 1;
10113 if (!event->parent) {
10114 if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
10115 err = get_callchain_buffers(attr->sample_max_stack);
10117 goto err_addr_filters;
10121 /* symmetric to unaccount_event() in _free_event() */
10122 account_event(event);
10127 kfree(event->addr_filters_offs);
10130 exclusive_event_destroy(event);
10133 if (event->destroy)
10134 event->destroy(event);
10135 module_put(pmu->module);
10137 if (is_cgroup_event(event))
10138 perf_detach_cgroup(event);
10140 put_pid_ns(event->ns);
10141 if (event->hw.target)
10142 put_task_struct(event->hw.target);
10145 return ERR_PTR(err);
10148 static int perf_copy_attr(struct perf_event_attr __user *uattr,
10149 struct perf_event_attr *attr)
10154 if (!access_ok(uattr, PERF_ATTR_SIZE_VER0))
10158 * zero the full structure, so that a short copy will be nice.
10160 memset(attr, 0, sizeof(*attr));
10162 ret = get_user(size, &uattr->size);
10166 if (size > PAGE_SIZE) /* silly large */
10169 if (!size) /* abi compat */
10170 size = PERF_ATTR_SIZE_VER0;
10172 if (size < PERF_ATTR_SIZE_VER0)
10176 * If we're handed a bigger struct than we know of,
10177 * ensure all the unknown bits are 0 - i.e. new
10178 * user-space does not rely on any kernel feature
10179 * extensions we dont know about yet.
10181 if (size > sizeof(*attr)) {
10182 unsigned char __user *addr;
10183 unsigned char __user *end;
10186 addr = (void __user *)uattr + sizeof(*attr);
10187 end = (void __user *)uattr + size;
10189 for (; addr < end; addr++) {
10190 ret = get_user(val, addr);
10196 size = sizeof(*attr);
10199 ret = copy_from_user(attr, uattr, size);
10205 if (attr->__reserved_1)
10208 if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
10211 if (attr->read_format & ~(PERF_FORMAT_MAX-1))
10214 if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
10215 u64 mask = attr->branch_sample_type;
10217 /* only using defined bits */
10218 if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
10221 /* at least one branch bit must be set */
10222 if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
10225 /* propagate priv level, when not set for branch */
10226 if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
10228 /* exclude_kernel checked on syscall entry */
10229 if (!attr->exclude_kernel)
10230 mask |= PERF_SAMPLE_BRANCH_KERNEL;
10232 if (!attr->exclude_user)
10233 mask |= PERF_SAMPLE_BRANCH_USER;
10235 if (!attr->exclude_hv)
10236 mask |= PERF_SAMPLE_BRANCH_HV;
10238 * adjust user setting (for HW filter setup)
10240 attr->branch_sample_type = mask;
10242 /* privileged levels capture (kernel, hv): check permissions */
10243 if ((mask & PERF_SAMPLE_BRANCH_PERM_PLM)
10244 && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10248 if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
10249 ret = perf_reg_validate(attr->sample_regs_user);
10254 if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
10255 if (!arch_perf_have_user_stack_dump())
10259 * We have __u32 type for the size, but so far
10260 * we can only use __u16 as maximum due to the
10261 * __u16 sample size limit.
10263 if (attr->sample_stack_user >= USHRT_MAX)
10265 else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
10269 if (!attr->sample_max_stack)
10270 attr->sample_max_stack = sysctl_perf_event_max_stack;
10272 if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
10273 ret = perf_reg_validate(attr->sample_regs_intr);
10278 put_user(sizeof(*attr), &uattr->size);
10284 perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
10286 struct ring_buffer *rb = NULL;
10292 /* don't allow circular references */
10293 if (event == output_event)
10297 * Don't allow cross-cpu buffers
10299 if (output_event->cpu != event->cpu)
10303 * If its not a per-cpu rb, it must be the same task.
10305 if (output_event->cpu == -1 && output_event->ctx != event->ctx)
10309 * Mixing clocks in the same buffer is trouble you don't need.
10311 if (output_event->clock != event->clock)
10315 * Either writing ring buffer from beginning or from end.
10316 * Mixing is not allowed.
10318 if (is_write_backward(output_event) != is_write_backward(event))
10322 * If both events generate aux data, they must be on the same PMU
10324 if (has_aux(event) && has_aux(output_event) &&
10325 event->pmu != output_event->pmu)
10329 mutex_lock(&event->mmap_mutex);
10330 /* Can't redirect output if we've got an active mmap() */
10331 if (atomic_read(&event->mmap_count))
10334 if (output_event) {
10335 /* get the rb we want to redirect to */
10336 rb = ring_buffer_get(output_event);
10341 ring_buffer_attach(event, rb);
10345 mutex_unlock(&event->mmap_mutex);
10351 static void mutex_lock_double(struct mutex *a, struct mutex *b)
10357 mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
10360 static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
10362 bool nmi_safe = false;
10365 case CLOCK_MONOTONIC:
10366 event->clock = &ktime_get_mono_fast_ns;
10370 case CLOCK_MONOTONIC_RAW:
10371 event->clock = &ktime_get_raw_fast_ns;
10375 case CLOCK_REALTIME:
10376 event->clock = &ktime_get_real_ns;
10379 case CLOCK_BOOTTIME:
10380 event->clock = &ktime_get_boot_ns;
10384 event->clock = &ktime_get_tai_ns;
10391 if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
10398 * Variation on perf_event_ctx_lock_nested(), except we take two context
10401 static struct perf_event_context *
10402 __perf_event_ctx_lock_double(struct perf_event *group_leader,
10403 struct perf_event_context *ctx)
10405 struct perf_event_context *gctx;
10409 gctx = READ_ONCE(group_leader->ctx);
10410 if (!atomic_inc_not_zero(&gctx->refcount)) {
10416 mutex_lock_double(&gctx->mutex, &ctx->mutex);
10418 if (group_leader->ctx != gctx) {
10419 mutex_unlock(&ctx->mutex);
10420 mutex_unlock(&gctx->mutex);
10429 * sys_perf_event_open - open a performance event, associate it to a task/cpu
10431 * @attr_uptr: event_id type attributes for monitoring/sampling
10434 * @group_fd: group leader event fd
10436 SYSCALL_DEFINE5(perf_event_open,
10437 struct perf_event_attr __user *, attr_uptr,
10438 pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
10440 struct perf_event *group_leader = NULL, *output_event = NULL;
10441 struct perf_event *event, *sibling;
10442 struct perf_event_attr attr;
10443 struct perf_event_context *ctx, *uninitialized_var(gctx);
10444 struct file *event_file = NULL;
10445 struct fd group = {NULL, 0};
10446 struct task_struct *task = NULL;
10449 int move_group = 0;
10451 int f_flags = O_RDWR;
10452 int cgroup_fd = -1;
10454 /* for future expandability... */
10455 if (flags & ~PERF_FLAG_ALL)
10458 err = perf_copy_attr(attr_uptr, &attr);
10462 if (!attr.exclude_kernel) {
10463 if (perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10467 if (attr.namespaces) {
10468 if (!capable(CAP_SYS_ADMIN))
10473 if (attr.sample_freq > sysctl_perf_event_sample_rate)
10476 if (attr.sample_period & (1ULL << 63))
10480 /* Only privileged users can get physical addresses */
10481 if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) &&
10482 perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN))
10486 * In cgroup mode, the pid argument is used to pass the fd
10487 * opened to the cgroup directory in cgroupfs. The cpu argument
10488 * designates the cpu on which to monitor threads from that
10491 if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
10494 if (flags & PERF_FLAG_FD_CLOEXEC)
10495 f_flags |= O_CLOEXEC;
10497 event_fd = get_unused_fd_flags(f_flags);
10501 if (group_fd != -1) {
10502 err = perf_fget_light(group_fd, &group);
10505 group_leader = group.file->private_data;
10506 if (flags & PERF_FLAG_FD_OUTPUT)
10507 output_event = group_leader;
10508 if (flags & PERF_FLAG_FD_NO_GROUP)
10509 group_leader = NULL;
10512 if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
10513 task = find_lively_task_by_vpid(pid);
10514 if (IS_ERR(task)) {
10515 err = PTR_ERR(task);
10520 if (task && group_leader &&
10521 group_leader->attr.inherit != attr.inherit) {
10527 err = mutex_lock_interruptible(&task->signal->cred_guard_mutex);
10532 * Reuse ptrace permission checks for now.
10534 * We must hold cred_guard_mutex across this and any potential
10535 * perf_install_in_context() call for this new event to
10536 * serialize against exec() altering our credentials (and the
10537 * perf_event_exit_task() that could imply).
10540 if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
10544 if (flags & PERF_FLAG_PID_CGROUP)
10547 event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
10548 NULL, NULL, cgroup_fd);
10549 if (IS_ERR(event)) {
10550 err = PTR_ERR(event);
10554 if (is_sampling_event(event)) {
10555 if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
10562 * Special case software events and allow them to be part of
10563 * any hardware group.
10567 if (attr.use_clockid) {
10568 err = perf_event_set_clock(event, attr.clockid);
10573 if (pmu->task_ctx_nr == perf_sw_context)
10574 event->event_caps |= PERF_EV_CAP_SOFTWARE;
10576 if (group_leader) {
10577 if (is_software_event(event) &&
10578 !in_software_context(group_leader)) {
10580 * If the event is a sw event, but the group_leader
10581 * is on hw context.
10583 * Allow the addition of software events to hw
10584 * groups, this is safe because software events
10585 * never fail to schedule.
10587 pmu = group_leader->ctx->pmu;
10588 } else if (!is_software_event(event) &&
10589 is_software_event(group_leader) &&
10590 (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10592 * In case the group is a pure software group, and we
10593 * try to add a hardware event, move the whole group to
10594 * the hardware context.
10601 * Get the target context (task or percpu):
10603 ctx = find_get_context(pmu, task, event);
10605 err = PTR_ERR(ctx);
10609 if ((pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE) && group_leader) {
10615 * Look up the group leader (we will attach this event to it):
10617 if (group_leader) {
10621 * Do not allow a recursive hierarchy (this new sibling
10622 * becoming part of another group-sibling):
10624 if (group_leader->group_leader != group_leader)
10627 /* All events in a group should have the same clock */
10628 if (group_leader->clock != event->clock)
10632 * Make sure we're both events for the same CPU;
10633 * grouping events for different CPUs is broken; since
10634 * you can never concurrently schedule them anyhow.
10636 if (group_leader->cpu != event->cpu)
10640 * Make sure we're both on the same task, or both
10643 if (group_leader->ctx->task != ctx->task)
10647 * Do not allow to attach to a group in a different task
10648 * or CPU context. If we're moving SW events, we'll fix
10649 * this up later, so allow that.
10651 if (!move_group && group_leader->ctx != ctx)
10655 * Only a group leader can be exclusive or pinned
10657 if (attr.exclusive || attr.pinned)
10661 if (output_event) {
10662 err = perf_event_set_output(event, output_event);
10667 event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
10669 if (IS_ERR(event_file)) {
10670 err = PTR_ERR(event_file);
10676 gctx = __perf_event_ctx_lock_double(group_leader, ctx);
10678 if (gctx->task == TASK_TOMBSTONE) {
10684 * Check if we raced against another sys_perf_event_open() call
10685 * moving the software group underneath us.
10687 if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
10689 * If someone moved the group out from under us, check
10690 * if this new event wound up on the same ctx, if so
10691 * its the regular !move_group case, otherwise fail.
10697 perf_event_ctx_unlock(group_leader, gctx);
10702 mutex_lock(&ctx->mutex);
10705 if (ctx->task == TASK_TOMBSTONE) {
10710 if (!perf_event_validate_size(event)) {
10717 * Check if the @cpu we're creating an event for is online.
10719 * We use the perf_cpu_context::ctx::mutex to serialize against
10720 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10722 struct perf_cpu_context *cpuctx =
10723 container_of(ctx, struct perf_cpu_context, ctx);
10725 if (!cpuctx->online) {
10733 * Must be under the same ctx::mutex as perf_install_in_context(),
10734 * because we need to serialize with concurrent event creation.
10736 if (!exclusive_event_installable(event, ctx)) {
10737 /* exclusive and group stuff are assumed mutually exclusive */
10738 WARN_ON_ONCE(move_group);
10744 WARN_ON_ONCE(ctx->parent_ctx);
10747 * This is the point on no return; we cannot fail hereafter. This is
10748 * where we start modifying current state.
10753 * See perf_event_ctx_lock() for comments on the details
10754 * of swizzling perf_event::ctx.
10756 perf_remove_from_context(group_leader, 0);
10759 for_each_sibling_event(sibling, group_leader) {
10760 perf_remove_from_context(sibling, 0);
10765 * Wait for everybody to stop referencing the events through
10766 * the old lists, before installing it on new lists.
10771 * Install the group siblings before the group leader.
10773 * Because a group leader will try and install the entire group
10774 * (through the sibling list, which is still in-tact), we can
10775 * end up with siblings installed in the wrong context.
10777 * By installing siblings first we NO-OP because they're not
10778 * reachable through the group lists.
10780 for_each_sibling_event(sibling, group_leader) {
10781 perf_event__state_init(sibling);
10782 perf_install_in_context(ctx, sibling, sibling->cpu);
10787 * Removing from the context ends up with disabled
10788 * event. What we want here is event in the initial
10789 * startup state, ready to be add into new context.
10791 perf_event__state_init(group_leader);
10792 perf_install_in_context(ctx, group_leader, group_leader->cpu);
10797 * Precalculate sample_data sizes; do while holding ctx::mutex such
10798 * that we're serialized against further additions and before
10799 * perf_install_in_context() which is the point the event is active and
10800 * can use these values.
10802 perf_event__header_size(event);
10803 perf_event__id_header_size(event);
10805 event->owner = current;
10807 perf_install_in_context(ctx, event, event->cpu);
10808 perf_unpin_context(ctx);
10811 perf_event_ctx_unlock(group_leader, gctx);
10812 mutex_unlock(&ctx->mutex);
10815 mutex_unlock(&task->signal->cred_guard_mutex);
10816 put_task_struct(task);
10819 mutex_lock(¤t->perf_event_mutex);
10820 list_add_tail(&event->owner_entry, ¤t->perf_event_list);
10821 mutex_unlock(¤t->perf_event_mutex);
10824 * Drop the reference on the group_event after placing the
10825 * new event on the sibling_list. This ensures destruction
10826 * of the group leader will find the pointer to itself in
10827 * perf_group_detach().
10830 fd_install(event_fd, event_file);
10835 perf_event_ctx_unlock(group_leader, gctx);
10836 mutex_unlock(&ctx->mutex);
10840 perf_unpin_context(ctx);
10844 * If event_file is set, the fput() above will have called ->release()
10845 * and that will take care of freeing the event.
10851 mutex_unlock(&task->signal->cred_guard_mutex);
10854 put_task_struct(task);
10858 put_unused_fd(event_fd);
10863 * perf_event_create_kernel_counter
10865 * @attr: attributes of the counter to create
10866 * @cpu: cpu in which the counter is bound
10867 * @task: task to profile (NULL for percpu)
10869 struct perf_event *
10870 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
10871 struct task_struct *task,
10872 perf_overflow_handler_t overflow_handler,
10875 struct perf_event_context *ctx;
10876 struct perf_event *event;
10880 * Get the target context (task or percpu):
10883 event = perf_event_alloc(attr, cpu, task, NULL, NULL,
10884 overflow_handler, context, -1);
10885 if (IS_ERR(event)) {
10886 err = PTR_ERR(event);
10890 /* Mark owner so we could distinguish it from user events. */
10891 event->owner = TASK_TOMBSTONE;
10893 ctx = find_get_context(event->pmu, task, event);
10895 err = PTR_ERR(ctx);
10899 WARN_ON_ONCE(ctx->parent_ctx);
10900 mutex_lock(&ctx->mutex);
10901 if (ctx->task == TASK_TOMBSTONE) {
10908 * Check if the @cpu we're creating an event for is online.
10910 * We use the perf_cpu_context::ctx::mutex to serialize against
10911 * the hotplug notifiers. See perf_event_{init,exit}_cpu().
10913 struct perf_cpu_context *cpuctx =
10914 container_of(ctx, struct perf_cpu_context, ctx);
10915 if (!cpuctx->online) {
10921 if (!exclusive_event_installable(event, ctx)) {
10926 perf_install_in_context(ctx, event, cpu);
10927 perf_unpin_context(ctx);
10928 mutex_unlock(&ctx->mutex);
10933 mutex_unlock(&ctx->mutex);
10934 perf_unpin_context(ctx);
10939 return ERR_PTR(err);
10941 EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
10943 void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
10945 struct perf_event_context *src_ctx;
10946 struct perf_event_context *dst_ctx;
10947 struct perf_event *event, *tmp;
10950 src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
10951 dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
10954 * See perf_event_ctx_lock() for comments on the details
10955 * of swizzling perf_event::ctx.
10957 mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
10958 list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
10960 perf_remove_from_context(event, 0);
10961 unaccount_event_cpu(event, src_cpu);
10963 list_add(&event->migrate_entry, &events);
10967 * Wait for the events to quiesce before re-instating them.
10972 * Re-instate events in 2 passes.
10974 * Skip over group leaders and only install siblings on this first
10975 * pass, siblings will not get enabled without a leader, however a
10976 * leader will enable its siblings, even if those are still on the old
10979 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10980 if (event->group_leader == event)
10983 list_del(&event->migrate_entry);
10984 if (event->state >= PERF_EVENT_STATE_OFF)
10985 event->state = PERF_EVENT_STATE_INACTIVE;
10986 account_event_cpu(event, dst_cpu);
10987 perf_install_in_context(dst_ctx, event, dst_cpu);
10992 * Once all the siblings are setup properly, install the group leaders
10995 list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
10996 list_del(&event->migrate_entry);
10997 if (event->state >= PERF_EVENT_STATE_OFF)
10998 event->state = PERF_EVENT_STATE_INACTIVE;
10999 account_event_cpu(event, dst_cpu);
11000 perf_install_in_context(dst_ctx, event, dst_cpu);
11003 mutex_unlock(&dst_ctx->mutex);
11004 mutex_unlock(&src_ctx->mutex);
11006 EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
11008 static void sync_child_event(struct perf_event *child_event,
11009 struct task_struct *child)
11011 struct perf_event *parent_event = child_event->parent;
11014 if (child_event->attr.inherit_stat)
11015 perf_event_read_event(child_event, child);
11017 child_val = perf_event_count(child_event);
11020 * Add back the child's count to the parent's count:
11022 atomic64_add(child_val, &parent_event->child_count);
11023 atomic64_add(child_event->total_time_enabled,
11024 &parent_event->child_total_time_enabled);
11025 atomic64_add(child_event->total_time_running,
11026 &parent_event->child_total_time_running);
11030 perf_event_exit_event(struct perf_event *child_event,
11031 struct perf_event_context *child_ctx,
11032 struct task_struct *child)
11034 struct perf_event *parent_event = child_event->parent;
11037 * Do not destroy the 'original' grouping; because of the context
11038 * switch optimization the original events could've ended up in a
11039 * random child task.
11041 * If we were to destroy the original group, all group related
11042 * operations would cease to function properly after this random
11045 * Do destroy all inherited groups, we don't care about those
11046 * and being thorough is better.
11048 raw_spin_lock_irq(&child_ctx->lock);
11049 WARN_ON_ONCE(child_ctx->is_active);
11052 perf_group_detach(child_event);
11053 list_del_event(child_event, child_ctx);
11054 perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
11055 raw_spin_unlock_irq(&child_ctx->lock);
11058 * Parent events are governed by their filedesc, retain them.
11060 if (!parent_event) {
11061 perf_event_wakeup(child_event);
11065 * Child events can be cleaned up.
11068 sync_child_event(child_event, child);
11071 * Remove this event from the parent's list
11073 WARN_ON_ONCE(parent_event->ctx->parent_ctx);
11074 mutex_lock(&parent_event->child_mutex);
11075 list_del_init(&child_event->child_list);
11076 mutex_unlock(&parent_event->child_mutex);
11079 * Kick perf_poll() for is_event_hup().
11081 perf_event_wakeup(parent_event);
11082 free_event(child_event);
11083 put_event(parent_event);
11086 static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
11088 struct perf_event_context *child_ctx, *clone_ctx = NULL;
11089 struct perf_event *child_event, *next;
11091 WARN_ON_ONCE(child != current);
11093 child_ctx = perf_pin_task_context(child, ctxn);
11098 * In order to reduce the amount of tricky in ctx tear-down, we hold
11099 * ctx::mutex over the entire thing. This serializes against almost
11100 * everything that wants to access the ctx.
11102 * The exception is sys_perf_event_open() /
11103 * perf_event_create_kernel_count() which does find_get_context()
11104 * without ctx::mutex (it cannot because of the move_group double mutex
11105 * lock thing). See the comments in perf_install_in_context().
11107 mutex_lock(&child_ctx->mutex);
11110 * In a single ctx::lock section, de-schedule the events and detach the
11111 * context from the task such that we cannot ever get it scheduled back
11114 raw_spin_lock_irq(&child_ctx->lock);
11115 task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
11118 * Now that the context is inactive, destroy the task <-> ctx relation
11119 * and mark the context dead.
11121 RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
11122 put_ctx(child_ctx); /* cannot be last */
11123 WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
11124 put_task_struct(current); /* cannot be last */
11126 clone_ctx = unclone_ctx(child_ctx);
11127 raw_spin_unlock_irq(&child_ctx->lock);
11130 put_ctx(clone_ctx);
11133 * Report the task dead after unscheduling the events so that we
11134 * won't get any samples after PERF_RECORD_EXIT. We can however still
11135 * get a few PERF_RECORD_READ events.
11137 perf_event_task(child, child_ctx, 0);
11139 list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
11140 perf_event_exit_event(child_event, child_ctx, child);
11142 mutex_unlock(&child_ctx->mutex);
11144 put_ctx(child_ctx);
11148 * When a child task exits, feed back event values to parent events.
11150 * Can be called with cred_guard_mutex held when called from
11151 * install_exec_creds().
11153 void perf_event_exit_task(struct task_struct *child)
11155 struct perf_event *event, *tmp;
11158 mutex_lock(&child->perf_event_mutex);
11159 list_for_each_entry_safe(event, tmp, &child->perf_event_list,
11161 list_del_init(&event->owner_entry);
11164 * Ensure the list deletion is visible before we clear
11165 * the owner, closes a race against perf_release() where
11166 * we need to serialize on the owner->perf_event_mutex.
11168 smp_store_release(&event->owner, NULL);
11170 mutex_unlock(&child->perf_event_mutex);
11172 for_each_task_context_nr(ctxn)
11173 perf_event_exit_task_context(child, ctxn);
11176 * The perf_event_exit_task_context calls perf_event_task
11177 * with child's task_ctx, which generates EXIT events for
11178 * child contexts and sets child->perf_event_ctxp[] to NULL.
11179 * At this point we need to send EXIT events to cpu contexts.
11181 perf_event_task(child, NULL, 0);
11184 static void perf_free_event(struct perf_event *event,
11185 struct perf_event_context *ctx)
11187 struct perf_event *parent = event->parent;
11189 if (WARN_ON_ONCE(!parent))
11192 mutex_lock(&parent->child_mutex);
11193 list_del_init(&event->child_list);
11194 mutex_unlock(&parent->child_mutex);
11198 raw_spin_lock_irq(&ctx->lock);
11199 perf_group_detach(event);
11200 list_del_event(event, ctx);
11201 raw_spin_unlock_irq(&ctx->lock);
11206 * Free an unexposed, unused context as created by inheritance by
11207 * perf_event_init_task below, used by fork() in case of fail.
11209 * Not all locks are strictly required, but take them anyway to be nice and
11210 * help out with the lockdep assertions.
11212 void perf_event_free_task(struct task_struct *task)
11214 struct perf_event_context *ctx;
11215 struct perf_event *event, *tmp;
11218 for_each_task_context_nr(ctxn) {
11219 ctx = task->perf_event_ctxp[ctxn];
11223 mutex_lock(&ctx->mutex);
11224 raw_spin_lock_irq(&ctx->lock);
11226 * Destroy the task <-> ctx relation and mark the context dead.
11228 * This is important because even though the task hasn't been
11229 * exposed yet the context has been (through child_list).
11231 RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
11232 WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
11233 put_task_struct(task); /* cannot be last */
11234 raw_spin_unlock_irq(&ctx->lock);
11236 list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
11237 perf_free_event(event, ctx);
11239 mutex_unlock(&ctx->mutex);
11244 void perf_event_delayed_put(struct task_struct *task)
11248 for_each_task_context_nr(ctxn)
11249 WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
11252 struct file *perf_event_get(unsigned int fd)
11256 file = fget_raw(fd);
11258 return ERR_PTR(-EBADF);
11260 if (file->f_op != &perf_fops) {
11262 return ERR_PTR(-EBADF);
11268 const struct perf_event *perf_get_event(struct file *file)
11270 if (file->f_op != &perf_fops)
11271 return ERR_PTR(-EINVAL);
11273 return file->private_data;
11276 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
11279 return ERR_PTR(-EINVAL);
11281 return &event->attr;
11285 * Inherit an event from parent task to child task.
11288 * - valid pointer on success
11289 * - NULL for orphaned events
11290 * - IS_ERR() on error
11292 static struct perf_event *
11293 inherit_event(struct perf_event *parent_event,
11294 struct task_struct *parent,
11295 struct perf_event_context *parent_ctx,
11296 struct task_struct *child,
11297 struct perf_event *group_leader,
11298 struct perf_event_context *child_ctx)
11300 enum perf_event_state parent_state = parent_event->state;
11301 struct perf_event *child_event;
11302 unsigned long flags;
11305 * Instead of creating recursive hierarchies of events,
11306 * we link inherited events back to the original parent,
11307 * which has a filp for sure, which we use as the reference
11310 if (parent_event->parent)
11311 parent_event = parent_event->parent;
11313 child_event = perf_event_alloc(&parent_event->attr,
11316 group_leader, parent_event,
11318 if (IS_ERR(child_event))
11319 return child_event;
11322 if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
11323 !child_ctx->task_ctx_data) {
11324 struct pmu *pmu = child_event->pmu;
11326 child_ctx->task_ctx_data = kzalloc(pmu->task_ctx_size,
11328 if (!child_ctx->task_ctx_data) {
11329 free_event(child_event);
11335 * is_orphaned_event() and list_add_tail(&parent_event->child_list)
11336 * must be under the same lock in order to serialize against
11337 * perf_event_release_kernel(), such that either we must observe
11338 * is_orphaned_event() or they will observe us on the child_list.
11340 mutex_lock(&parent_event->child_mutex);
11341 if (is_orphaned_event(parent_event) ||
11342 !atomic_long_inc_not_zero(&parent_event->refcount)) {
11343 mutex_unlock(&parent_event->child_mutex);
11344 /* task_ctx_data is freed with child_ctx */
11345 free_event(child_event);
11349 get_ctx(child_ctx);
11352 * Make the child state follow the state of the parent event,
11353 * not its attr.disabled bit. We hold the parent's mutex,
11354 * so we won't race with perf_event_{en, dis}able_family.
11356 if (parent_state >= PERF_EVENT_STATE_INACTIVE)
11357 child_event->state = PERF_EVENT_STATE_INACTIVE;
11359 child_event->state = PERF_EVENT_STATE_OFF;
11361 if (parent_event->attr.freq) {
11362 u64 sample_period = parent_event->hw.sample_period;
11363 struct hw_perf_event *hwc = &child_event->hw;
11365 hwc->sample_period = sample_period;
11366 hwc->last_period = sample_period;
11368 local64_set(&hwc->period_left, sample_period);
11371 child_event->ctx = child_ctx;
11372 child_event->overflow_handler = parent_event->overflow_handler;
11373 child_event->overflow_handler_context
11374 = parent_event->overflow_handler_context;
11377 * Precalculate sample_data sizes
11379 perf_event__header_size(child_event);
11380 perf_event__id_header_size(child_event);
11383 * Link it up in the child's context:
11385 raw_spin_lock_irqsave(&child_ctx->lock, flags);
11386 add_event_to_ctx(child_event, child_ctx);
11387 raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
11390 * Link this into the parent event's child list
11392 list_add_tail(&child_event->child_list, &parent_event->child_list);
11393 mutex_unlock(&parent_event->child_mutex);
11395 return child_event;
11399 * Inherits an event group.
11401 * This will quietly suppress orphaned events; !inherit_event() is not an error.
11402 * This matches with perf_event_release_kernel() removing all child events.
11408 static int inherit_group(struct perf_event *parent_event,
11409 struct task_struct *parent,
11410 struct perf_event_context *parent_ctx,
11411 struct task_struct *child,
11412 struct perf_event_context *child_ctx)
11414 struct perf_event *leader;
11415 struct perf_event *sub;
11416 struct perf_event *child_ctr;
11418 leader = inherit_event(parent_event, parent, parent_ctx,
11419 child, NULL, child_ctx);
11420 if (IS_ERR(leader))
11421 return PTR_ERR(leader);
11423 * @leader can be NULL here because of is_orphaned_event(). In this
11424 * case inherit_event() will create individual events, similar to what
11425 * perf_group_detach() would do anyway.
11427 for_each_sibling_event(sub, parent_event) {
11428 child_ctr = inherit_event(sub, parent, parent_ctx,
11429 child, leader, child_ctx);
11430 if (IS_ERR(child_ctr))
11431 return PTR_ERR(child_ctr);
11437 * Creates the child task context and tries to inherit the event-group.
11439 * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
11440 * inherited_all set when we 'fail' to inherit an orphaned event; this is
11441 * consistent with perf_event_release_kernel() removing all child events.
11448 inherit_task_group(struct perf_event *event, struct task_struct *parent,
11449 struct perf_event_context *parent_ctx,
11450 struct task_struct *child, int ctxn,
11451 int *inherited_all)
11454 struct perf_event_context *child_ctx;
11456 if (!event->attr.inherit) {
11457 *inherited_all = 0;
11461 child_ctx = child->perf_event_ctxp[ctxn];
11464 * This is executed from the parent task context, so
11465 * inherit events that have been marked for cloning.
11466 * First allocate and initialize a context for the
11469 child_ctx = alloc_perf_context(parent_ctx->pmu, child);
11473 child->perf_event_ctxp[ctxn] = child_ctx;
11476 ret = inherit_group(event, parent, parent_ctx,
11480 *inherited_all = 0;
11486 * Initialize the perf_event context in task_struct
11488 static int perf_event_init_context(struct task_struct *child, int ctxn)
11490 struct perf_event_context *child_ctx, *parent_ctx;
11491 struct perf_event_context *cloned_ctx;
11492 struct perf_event *event;
11493 struct task_struct *parent = current;
11494 int inherited_all = 1;
11495 unsigned long flags;
11498 if (likely(!parent->perf_event_ctxp[ctxn]))
11502 * If the parent's context is a clone, pin it so it won't get
11503 * swapped under us.
11505 parent_ctx = perf_pin_task_context(parent, ctxn);
11510 * No need to check if parent_ctx != NULL here; since we saw
11511 * it non-NULL earlier, the only reason for it to become NULL
11512 * is if we exit, and since we're currently in the middle of
11513 * a fork we can't be exiting at the same time.
11517 * Lock the parent list. No need to lock the child - not PID
11518 * hashed yet and not running, so nobody can access it.
11520 mutex_lock(&parent_ctx->mutex);
11523 * We dont have to disable NMIs - we are only looking at
11524 * the list, not manipulating it:
11526 perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
11527 ret = inherit_task_group(event, parent, parent_ctx,
11528 child, ctxn, &inherited_all);
11534 * We can't hold ctx->lock when iterating the ->flexible_group list due
11535 * to allocations, but we need to prevent rotation because
11536 * rotate_ctx() will change the list from interrupt context.
11538 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11539 parent_ctx->rotate_disable = 1;
11540 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11542 perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
11543 ret = inherit_task_group(event, parent, parent_ctx,
11544 child, ctxn, &inherited_all);
11549 raw_spin_lock_irqsave(&parent_ctx->lock, flags);
11550 parent_ctx->rotate_disable = 0;
11552 child_ctx = child->perf_event_ctxp[ctxn];
11554 if (child_ctx && inherited_all) {
11556 * Mark the child context as a clone of the parent
11557 * context, or of whatever the parent is a clone of.
11559 * Note that if the parent is a clone, the holding of
11560 * parent_ctx->lock avoids it from being uncloned.
11562 cloned_ctx = parent_ctx->parent_ctx;
11564 child_ctx->parent_ctx = cloned_ctx;
11565 child_ctx->parent_gen = parent_ctx->parent_gen;
11567 child_ctx->parent_ctx = parent_ctx;
11568 child_ctx->parent_gen = parent_ctx->generation;
11570 get_ctx(child_ctx->parent_ctx);
11573 raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
11575 mutex_unlock(&parent_ctx->mutex);
11577 perf_unpin_context(parent_ctx);
11578 put_ctx(parent_ctx);
11584 * Initialize the perf_event context in task_struct
11586 int perf_event_init_task(struct task_struct *child)
11590 memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
11591 mutex_init(&child->perf_event_mutex);
11592 INIT_LIST_HEAD(&child->perf_event_list);
11594 for_each_task_context_nr(ctxn) {
11595 ret = perf_event_init_context(child, ctxn);
11597 perf_event_free_task(child);
11605 static void __init perf_event_init_all_cpus(void)
11607 struct swevent_htable *swhash;
11610 zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
11612 for_each_possible_cpu(cpu) {
11613 swhash = &per_cpu(swevent_htable, cpu);
11614 mutex_init(&swhash->hlist_mutex);
11615 INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
11617 INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
11618 raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
11620 #ifdef CONFIG_CGROUP_PERF
11621 INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
11623 INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
11627 void perf_swevent_init_cpu(unsigned int cpu)
11629 struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
11631 mutex_lock(&swhash->hlist_mutex);
11632 if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
11633 struct swevent_hlist *hlist;
11635 hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
11637 rcu_assign_pointer(swhash->swevent_hlist, hlist);
11639 mutex_unlock(&swhash->hlist_mutex);
11642 #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
11643 static void __perf_event_exit_context(void *__info)
11645 struct perf_event_context *ctx = __info;
11646 struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
11647 struct perf_event *event;
11649 raw_spin_lock(&ctx->lock);
11650 ctx_sched_out(ctx, cpuctx, EVENT_TIME);
11651 list_for_each_entry(event, &ctx->event_list, event_entry)
11652 __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
11653 raw_spin_unlock(&ctx->lock);
11656 static void perf_event_exit_cpu_context(int cpu)
11658 struct perf_cpu_context *cpuctx;
11659 struct perf_event_context *ctx;
11662 mutex_lock(&pmus_lock);
11663 list_for_each_entry(pmu, &pmus, entry) {
11664 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11665 ctx = &cpuctx->ctx;
11667 mutex_lock(&ctx->mutex);
11668 smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
11669 cpuctx->online = 0;
11670 mutex_unlock(&ctx->mutex);
11672 cpumask_clear_cpu(cpu, perf_online_mask);
11673 mutex_unlock(&pmus_lock);
11677 static void perf_event_exit_cpu_context(int cpu) { }
11681 int perf_event_init_cpu(unsigned int cpu)
11683 struct perf_cpu_context *cpuctx;
11684 struct perf_event_context *ctx;
11687 perf_swevent_init_cpu(cpu);
11689 mutex_lock(&pmus_lock);
11690 cpumask_set_cpu(cpu, perf_online_mask);
11691 list_for_each_entry(pmu, &pmus, entry) {
11692 cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
11693 ctx = &cpuctx->ctx;
11695 mutex_lock(&ctx->mutex);
11696 cpuctx->online = 1;
11697 mutex_unlock(&ctx->mutex);
11699 mutex_unlock(&pmus_lock);
11704 int perf_event_exit_cpu(unsigned int cpu)
11706 perf_event_exit_cpu_context(cpu);
11711 perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
11715 for_each_online_cpu(cpu)
11716 perf_event_exit_cpu(cpu);
11722 * Run the perf reboot notifier at the very last possible moment so that
11723 * the generic watchdog code runs as long as possible.
11725 static struct notifier_block perf_reboot_notifier = {
11726 .notifier_call = perf_reboot,
11727 .priority = INT_MIN,
11730 void __init perf_event_init(void)
11734 idr_init(&pmu_idr);
11736 perf_event_init_all_cpus();
11737 init_srcu_struct(&pmus_srcu);
11738 perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
11739 perf_pmu_register(&perf_cpu_clock, NULL, -1);
11740 perf_pmu_register(&perf_task_clock, NULL, -1);
11741 perf_tp_register();
11742 perf_event_init_cpu(smp_processor_id());
11743 register_reboot_notifier(&perf_reboot_notifier);
11745 ret = init_hw_breakpoint();
11746 WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
11749 * Build time assertion that we keep the data_head at the intended
11750 * location. IOW, validation we got the __reserved[] size right.
11752 BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
11756 ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
11759 struct perf_pmu_events_attr *pmu_attr =
11760 container_of(attr, struct perf_pmu_events_attr, attr);
11762 if (pmu_attr->event_str)
11763 return sprintf(page, "%s\n", pmu_attr->event_str);
11767 EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
11769 static int __init perf_event_sysfs_init(void)
11774 mutex_lock(&pmus_lock);
11776 ret = bus_register(&pmu_bus);
11780 list_for_each_entry(pmu, &pmus, entry) {
11781 if (!pmu->name || pmu->type < 0)
11784 ret = pmu_dev_alloc(pmu);
11785 WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
11787 pmu_bus_running = 1;
11791 mutex_unlock(&pmus_lock);
11795 device_initcall(perf_event_sysfs_init);
11797 #ifdef CONFIG_CGROUP_PERF
11798 static struct cgroup_subsys_state *
11799 perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
11801 struct perf_cgroup *jc;
11803 jc = kzalloc(sizeof(*jc), GFP_KERNEL);
11805 return ERR_PTR(-ENOMEM);
11807 jc->info = alloc_percpu(struct perf_cgroup_info);
11810 return ERR_PTR(-ENOMEM);
11816 static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
11818 struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
11820 free_percpu(jc->info);
11824 static int __perf_cgroup_move(void *info)
11826 struct task_struct *task = info;
11828 perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
11833 static void perf_cgroup_attach(struct cgroup_taskset *tset)
11835 struct task_struct *task;
11836 struct cgroup_subsys_state *css;
11838 cgroup_taskset_for_each(task, css, tset)
11839 task_function_call(task, __perf_cgroup_move, task);
11842 struct cgroup_subsys perf_event_cgrp_subsys = {
11843 .css_alloc = perf_cgroup_css_alloc,
11844 .css_free = perf_cgroup_css_free,
11845 .attach = perf_cgroup_attach,
11847 * Implicitly enable on dfl hierarchy so that perf events can
11848 * always be filtered by cgroup2 path as long as perf_event
11849 * controller is not mounted on a legacy hierarchy.
11851 .implicit_on_dfl = true,
11854 #endif /* CONFIG_CGROUP_PERF */